Biodiversity loss in the genus Artemia in the Western Mediterranean Region

Local populations extinctions depend on intrinsic factors related to the biology of species, as well as on direct threats of stochastic and/or deterministic type. The species of the genus Artemia (Branchiopoda, Anostraca), conspicuous inhabitants of hypersaline ecosystems, are suffering an important biodiversity loss. Their persistence is dramatically affected by deterministic factors threatening their biotopes. Among these deterministic factors the loss of habitats and the introduction of exotic invasive species are the most relevant. This paper aims to summarize the information available on: a) the abandonment of solar salterns in theWestern Mediterranean region; b) the present distribution of the exotic invasive species Artemia franciscana populations in Spain, Portugal, Italy and France; c) several reproductive parameters obtained from the study of life tables, performed for several autochthonous species and strains and the invasive species. These traits, linked to the quantitative and qualitative offspring output, allow an experimental approach to the understanding of the fitness superiority of the invasive species, as well as to the competitive displacement of the autochthonous Artemia species in the Western Mediterranean region.La extinción de poblaciones locales depende de factores intrínsecos que tienen que ver con la biología de las especies, así como de amenazas directas de tipo estocástico o determinístico. Las especies del género Artemia (Branchiopoda, Anostraca), conspicuos pobladores de humedales hipersalinos, están sufriendo una importante pérdida en biodiversidad. Su persistencia se ve dramáticamente afectada por factores determinísticos que amenazan a sus biotopos. De entre estos factores, la pérdida de hábitats y la introducción de especies exóticas invasoras son los más relevantes. Este trabajo pretende resumir la información disponible sobre: a) el abandono de salinas solares en la región del Mediterráneo Occidental; b) la distribución actual de poblaciones de la especie exótica invasora Artemia franciscana en España, Portugal, Italia y Francia; c) varios parámetros reproductivos obtenidos del estudio de tablas de vida, llevadas a cabo para varias especies y estirpes autóctonas y la especie invasora. Estos aspectos cuantitativos y cualitativos de la descendencia permiten una aproximación experimental a la comprensión de la superior eficacia biológica de la especie invasora, así como del desplazamiento por competencia de las especies autóctonas de Artemia en la región del Mediterráneo Occidental

Modelización de empresas financieras mediante series temporales

En este trabajo se realiza un estudio del mercado de acciones a partir de los datos de las cotizaciones de cinco empresas del IBEX 35. El trabajo consiste en realizar un análisis de series temporales con el fin de encontrar un modelo para cada una de las empresas que pueda reflejar el comportamiento de las acciones y nos permita hacer predicciones fiables para hacer buenas inversiones. Según la naturaleza de cada serie, dividiremos este trabajo en dos partes: - Una primera parte donde las cotizaciones de algunas de las empresas siguen modelos lineales, para lo que emplearemos modelos ARIMA. - Una segunda parte para las cotizaciones de las otras empresas que siguen modelos no lineales, para lo que emplearemos los modelos GARCH.Grado en Estadístic

Studies on the characterisation of biomarkers of nutritionally-derived stress in paralarval cultures of the common octopus (Octopus vulgaris)

Comunicación presentada en las CephsInAction MC & WGs meetings, celebradas en Barcelona, España, del 14 al 16 de marzo de 2014 Nowadays, due to the high mortality within the first 30 days of life, octopus paralarvae culture represents the main obstacle for commercial production of this species. The causes of such mortality are not yet well defined and understood. As a part of a broader project aimed at characterising the causes of such massive mortality, we envisaged the study of nutritionally-derived stress, through the selection of biomarkers capable of its detection and quantification.This research was supported by “Ministerio de Ciencia e Innovación” through the OCTOPHYS Project (AGL-2010-22120-C03-02), and by a Marie Curie R.G. (PERG08-GA-2010-276916, LONGFA). The study was also carried out under the scope of a PROMETEO Project (2010/006) from Generalitat Valenciana.Peer Reviewe

A MCDM methodology to determine the most critical variables in the pressure drop and heat transfer in minichannels

This paper proposes a methodology aiming at determining the most influent working variables and geometrical parameters over the pressure drop and heat transfer during the condensation process of several refrigerant gases using heat exchangers with pipes mini channels technology. A multi-criteria decision making (MCDM) methodology was used; this MCDM includes a mathematical method called SIMUS (Sequential Interactive Modelling for Urban Systems) that was applied to the results of 2543 tests obtained by using a designed refrigeration rig in which five different refrigerants (R32, R134a, R290, R410A and R1234yf) and two different tube geometries were tested. This methodology allows us to reduce the computational cost compared to the use of neural networks or other model development systems. This research shows six variables out of 39 that better define simultaneously the minimum pressure drop, as well as the maximum heat transfer, saturation pressure fluid entering the condenser being the most important one. Another aim of this research was to highlight a new methodology based on operation research for their application to improve the heat transfer energy efficiency and reduce the CO2 footprint derived of the use of heat exchangers with minichannels.Eloy Hontoria is grateful to Project RTI2018-099139-B-C21 financed by FEDER/ Ministerio de Ciencia e Innovación-Agencia Estatal de Investigación

Biosynthesis of essential fatty acids in Octopus vulgaris (Cuvier, 1797): Molecular cloning, functional characterisation and tissue distribution of a fatty acyl elongase

Polyunsaturated fatty acids (PUFA) have been identified as key nutrients for the common octopus (Octopus vulgaris), particularly for its early life-cycle stages (paralarvae). Our overarching aim is to establish the essential fatty acid (FA) requirements for octopus paralarvae through determination of the enzymes of endogenous PUFA biosynthetic pathways. We here report on the molecular cloning and functional characterisation of a cDNA encoding a putative elongase of very long-chain fatty acids (Elovl), a critical enzyme that mediate the elongation of FA including PUFA. Our results suggested that the octopus Elovl is phylogenetically related to Elovl5 and Elovl2, two elongases with demonstrated roles in PUFA biosynthesis in vertebrates. Further evidence supporting a role of the octopus Elovl in PUFA biosynthesis was provided through functional characterisation of its activity in yeast. It was confirmed that expression of the octopus Elovl conferred on yeast the ability to elongate some C18 and C20 PUFA, while C22 PUFA substrates remained unmodified. The substrate specificities exhibited by the octopus elongase were consistent with those of vertebrate Elovl5. Interestingly, the octopus Elovl elongated n-6 PUFA substrates more efficiently than their analogous n-3 substrates, suggesting that n-6 PUFA may have particular biological significance in O. vulgaris. Finally, we investigated the potential role of the newly cloned Elovl in the biosynthesis of non-methylene-interrupted FA, compounds typically found in marine invertebrates and confirmed to be also present in the common octopus

Investigating the essential fatty acids in the common cuttlefish Sepia officinalis (Mollusca, Cephalopoda): Molecular cloning and functional characterisation of fatty acyl desaturase and elongase

Some polyunsaturated fatty acids (PUFA) play critical roles in physiology and are essential for normal growth and development of aquatic animals including cephalopods like the common cuttlefish Sepia officinalis. This is particularly true for early life stages when neuronal tissues are rapidly developing and accumulating PUFA. The specific fatty acids (FAs) that can satisfy the essential requirements of any animal species depend upon the enzymatic capability to convert dietary FA into those physiologically important FAs required for normal function. In order to identify the dietary essential FA for the common cuttlefish, we have performed the molecular cloning and functional characterisation of two key enzymes involved in PUFA biosynthesis in this species, namely a fatty acyl desaturase (Fad) and an elongation of very long-chain fatty acid (Elovl) protein. The gene product of the cuttlefish Fad exhibited ∆5-desaturase activity, enabling this species to potentially biosynthesise the physiologically essential FAs eicosapentaenoic (20:5n-3, EPA) and arachidonic (20:4n-3, ARA) acids from 20:4n-3 and 20:3n-6, respectively. However, the cuttlefish Fad did not show ∆6 or ∆8 activity and therefore the biosynthesis of EPA and ARA from C18 PUFA precursors could be limited, suggesting that both may be essential FAs for cuttlefish. Moreover, the cuttlefish Fad also lacked ∆4-desaturase activity suggesting that DHA biosynthesis was not possible and thus DHA is also an essential FA for this species. The cuttlefish ∆5 Fad was able to produce non-methylene-interrupted (NMI) FA, a group of PUFAs typically found in marine invertebrates. The cuttlefish Elovl was able to elongate C18 and C20 PUFA substrates, but showed no activity towards C22 PUFA. Overall the results obtained in the present study allowed the prediction of the biosynthetic pathways of PUFA, including NMI FA, in the common cuttlefish. It was concluded that EPA, ARA and DHA were likely to be essential dietary FA for this species as endogenous production from precursor FA appears to be limited

Modelling and real-data validation of a logistic centre using TRNSYS®: Influences of the envelope, infiltrations and stored goods

In this paper, the authors aim to support users when modelling scenarios with complex processes entailing thermal loads and infiltrations. The large building analysed is a logistics centre for the replenishment and distribution of perishable foodstuffs where cold chains must be maintained. The logistics centre, with 96 loading/unloading docks, handles large turnovers of different goods. This produces heat inside the facility. Due to continuous loading/unloading, the infiltrations in the building, and the fixed and variable thermal loads, this facility consumes a large amount of energy. Aiming to optimise the centre and contribute to sustainable development goal SDG7, this building has been modelled with a classical non-D envelope using TRNBuild® and also with the more sophisticated 3D software, SketchUp®, to compare and validate their results over a year with real consumption, as well as to assess the main sources of energy consumption. To obtain reliable results, the authors provide some methodology models to identify the sources of the building's thermal losses and quantify the different sources of consumption. These models are useful tools to support decision-makers (to improve insulation and arrange loads, among other things) when trying to reduce energy use in large buildings with intense operating processes. The results indicate that by modelling the entire facility with 3D software, the model estimation differs from real consumption by around 7.22%, while using a non-D model increases the difference to 26%. Additionally, the results show that around 47% of the energy consumption in the building is due to air infiltrations during loading/unloading, 18% is due to perishable products, and around 30% is due to building insulation. The methodology and models presented here, including the possibility of modifying the thermal load profiles, have demonstrated their capacity to reduce and optimise the load demand of refrigeration for warehouses if reliable data records are available.This research was funded by RTI2018-099139-B-C21 from Ministry of Science and Innovation - National Research Agency (MCIN/AEI) 10.13039/501100011033 and by ‘‘ERDF A way of making Europe” of the ‘‘European Union”

Functionally diverse front-end desaturases are widespread in the phylum Annelida

Funding: This study was funded through the project IMPROMEGA Agencia Española de Investigación, Spain, grant no. RTI2018-095119-B-100, MCIN/AEI/ FEDER/UE / MCIN/AEI/10.13039/501100011033/ and FEDER "A way to make Europe". Additionally, this study forms part of the ThinkInAzul programme and was supported by MCIN with funding from European Union NextGenerationEU (PRTR-C17.I1) and by Generalitat Valenciana (THINKINAZUL/2021/26).Aquatic single-cell organisms have long been believed to be unique primary producers of omega-3 long-chain (≥C20) polyunsaturated fatty acids (ω3 LC-PUFA). Multiple invertebrates including annelids have been discovered to possess methyl-end desaturases enabling key steps in the de novo synthesis of ω3 LC-PUFA, and thus potentially contributing to their production in the ocean. Along methyl-end desaturases, the repertoire and function of further LC-PUFA biosynthesising enzymes is largely missing in Annelida. In this study we examined the front-end desaturase gene repertoire across the phylum Annelida, from Polychaeta and Clitellata, major classes of annelids comprising most annelid diversity. We further characterised the functions of the encoded enzymes in selected representative species by using a heterologous expression system based in yeast, demonstrating that functions of Annelida front-end desaturases have highly diversified during their expansion in both terrestrial and aquatic ecosystems. We concluded that annelids possess at least two front-end desaturases with Δ5 and Δ6Δ8 desaturase regioselectivities, enabling all the desaturation reactions required to convert the C18 precursors into the physiologically relevant LC-PUFA such as eicosapentaenoic and arachidonic acids, but not docosahexaenoic acid. Such a gene complement is conserved across the different taxonomic groups within Annelida.Publisher PDFPeer reviewe