359 research outputs found

    Analysis of NPF and NRT transporter families regarding the nitrate nutrition in maritime pine (Pinus pinaster)

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    Nitrogen is an essential element for life and the main limiting nutrient for plant growth and development1. The main forms of inorganic nitrogen in soils are nitrate and ammonium, which relative abundances depend on environmental conditions such as temperature. In agricultural soils the most abundant nitrogen form is nitrate because the use of chemical fertilizers however in natural ecosystems nitrogen soil composition can be more complex. Conifers are tree gymnosperms with a wide distribution although their large forests dominate the boreal ecosystems where nitrification is limited and ammonium is the main nitrogen soil source2. In this context, conifers have an appreciable tolerance to ammonium. Maritime pine (Pinus pinaster Aiton) is a conifer from the western Mediterranean region of high economic and ecological interest in Spain, France and Portugal. This pine is also a research model tree with different genomic resources such as a reference transcriptome and a gene expression atlas3. Taking advantage of these resources the members of the NPF and NRT transporter families involved in nitrate uptake and transport have been identified and analyzed in maritime pine4. Among the transporter families, the NRT3 one is expanded and composed by six members. The capacity of maritime pine to use nitrate or ammonium has been analyzed in seedlings. The development and growth responses to nitrate nutrition are comparable to ammonium supply. At molecular level, there are strong gene expressions for genes involved in nitrate uptake and assimilation such as Nitrate Reductase, Nitrite Reductase, Glutamine Synthetase 1a, three NRT3 genes and different NPF family members in the different organs. Since the NPF proteins can transport different metabolites, peptides and hormones, the NPF transporters involved in nitrate transport are being identified.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This project was supported by the grant MicroNUpE, BIO2015-73512-JIN; MINECO/AEI/FEDER, UE. JMVM was supported by a grant from the Spanish Ministerio de Educación y Formación Profesional (FPU17/03517) and FO by a grant from the Universidad de Málaga (Programa Operativo de Empleo Juvenil vía SNJG, UMAJI11, FEDER, FSE, Junta de Andalucía)

    An unexpected actor in ammonium assimilation in conifer trees

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    Conifers are tree species with enormous environmental and economic interests but with several characteristics that complicate their investigation (big size, secondary compounds, large long-life cycles, megagenomes…). However, they are well adapted to ammonium-rich soils being a good model to study ammonium assimilation in plants. Although they have a special feature, only two glutamine synthetase (GS, EC 6.3.1.2) genes, GS1a and GS1b, coding for cytosolic proteins, have been identified. In angiosperms and in the gymnosperm Ginkgo biloba there are two types of this enzyme responsible of the ammonium assimilation: GS1 expressed in the cytosol and GS2 in the plastids. Until the date, the searches of new GS1 and GS2 genes in conifers have been made with classical biochemical and molecular biology techniques without satisfactory results. In the present context, the emergence of the next generation sequencing (NGS) techniques has open new opportunities in the resolution of old problems. They have allowed the whole sequencing of the massive conifer genomes and the analysis of their transcriptomes. Thus, in the framework of the European project ProCoGen, a gene expression atlas of the tissues of one-month seedlings was carried out using laser capture microdissection (LCM) and massive sequencing in maritime pine (Pinus pinaster), which is a conifer tree from the Southwestern Mediterranean region1. From the analysis of this work, a new gene coding for a new putative cytosolic GS has been identified, PpGS1c. 1Cañas, RA et al. (2017). Plant J, 91. 1064-1087Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Project funding by Ministerio de Economía y Competitividad BIO2015-69285-R and MicroNUpE (BIO2015-73512-JIN; MINECO/AEI/FEDER, UE

    Transcriptomics of ammonium nutrition in the conifer Pinus pinaster Aiton

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    Nitrogen is an important element for all living beings because it is part of macromolecules as significant as nucleic acids or amino acids. For plants, it constitutes a limiting factor in their growth and development1 due to their low natural availability in soils thus limiting primary production in ecosystems2. Conifers are a group of gymnosperm plants that form large forest extensions of vegetation, being the main constituents of forests in boreal ecosystems3 where ammonium is the main source of inorganic nitrogen4. Due to the characteristics of the soils in which conifers usually grow, these plants have developed a high tolerance to the presence of ammonium, which may constitute their main source of inorganic nitrogen5. The maritime pine (Pinus pinaster Aiton) is a conifer that has a wide distribution in the western Mediterranean area and has been widely used in reforestation, soil stabilization tasks and industrially. In recent years, maritime pine has been the subject of multiple omic studies that have resulted in the acquisition of important tools and resources6,7. The present work is focused on the analysis of the ammonium uptake and management efficiency, and its relationship with the biomass accumulation in maritime pine. For this purpose, several experiments have been developed in which pine seedlings have undergone different levels of ammonium nutrition, both in the short and long term. As a result of short-term experiments, the characterization of transcriptomic response to the process of ammonium nutrition (uptake and assimilation) is being studied at mRNA, lncRNA and miRNA level in roots. In relation to long-term experiments, ten different provenances of maritime pine seedlings were treated with different ammonium levels and the biomass changes were measured. The results obtained suggest the existence a certain phenotypic plasticity grade for this conifer.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This project was supported by a grant form the Spanish Ministerio de Ciencia, Innovación y Universidades (MicroNUpE, BIO2015-73512-JIN; MINECO/AEI/FEDER, UE). FO was supported by a grant from the Universidad de Málaga (Programa Operativo de Empleo Juvenil vía SNJG, UMAJI11, FEDER, FSE, Junta de Andalucía) and JMVM by a grant from the Spanish Ministerio de Educación y Formación Profesional (FPU17/03517

    Energy-momentum scheme for nonlinear thermo-electro-elastodynamics

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    The present contribution aims at the consistent discretisation of nonlinear, coupled thermoelectro-elastodynamics. In that regard, a new one-step implicit and thermodynamically consistent energymomentum integration scheme for the simulation of thermo-electro-elastic processes undergoing large deformations will be presented. The consideration is based upon polyconvexity inspired, constitutive models and a new tensor cross product algebra, which facilitate the design of the so-called discrete derivatives. The discrete derivatives are fundamental for the algorithmic evaluation of stresses and other derived variables like entropy density or the absolute temperature leading to a structure preserving integration scheme. In particular, recently published works of the authors concerning consistent time integration of large deformation thermo-elastodynamics and electro-elastodynamics are combined to a unified integration scheme. Numerical computations demonstrate the stability and conservation properties of the proposed energy-momentum scheme

    A polyconvex transversely-isotropic invariant-based formulation for electro-mechanics: stability, minimisers and computational implementation

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    The fabrication of evermore sophisticated miniaturised soft robotic components made up of Electro-Active Polymers (EAPs) is constantly demanding parallel development from the in-silico simulation point of view. The incorporation of crystallographic anisotropic micro-architectures, within an otherwise nearly uniform isotropic soft polymer matrix, has shown great potential in terms of advanced three-dimensional actuation (i.e. stretching, bending, twisting), especially at large strains, that is, beyond the onset of geometrical pull-in instabilities. To accommodate for this in-silico response, this paper presents a phenomenological invariant-based polyconvex transversely isotropic framework for the simulation of EAPs at large strains. This research expands previous work developed by Gil and Ortigosa for isotropic EAPs with the help of the pioneering work by Schr\"{o}eder and Neff in the context of polyconvexity for materials endowed with crystallographic architectures in single physics mechanics. The paper also summarises key important results both in terms of the existence of minimisers and material stability. In addition, a series of numerical examples is presented in order to demonstrate the effect that the anisotropic orientation and the contrast of material properties, as well as the level of deformation and electric field, have upon the response of the EAP when subjected to large three-dimensional stretching, bending and torsion, including the possible development of wrinkling

    An energy-momentum consistent time integration scheme based on a mixed framework for non-linear electro-elastodynamics

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    The objective of the present work is the introduction of new mixed variational principles for EM time integrators in electromechanics, hence bridging the gap between the previous work presented by the authors in References [11] and [1], opening up the possibility to a variety of new Finite Element implementations

    A first order hyperbolic framework for large strain computational solid dynamics. Part I: Total Lagrangian isothermal elasticity

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    This paper introduces a new computational framework for the analysis of large strain fast solid dynamics. The paper builds upon previous work published by the authors (Gil etal., 2014) [48], where a first order system of hyperbolic equations is introduced for the simulation of isothermal elastic materials in terms of the linear momentum, the deformation gradient and its Jacobian as unknown variables. In this work, the formulation is further enhanced with four key novelties. First, the use of a new geometric conservation law for the co-factor of the deformation leads to an enhanced mixed formulation, advantageous in those scenarios where the co-factor plays a dominant role. Second, the use of polyconvex strain energy functionals enables the definition of generalised convex entropy functions and associated entropy fluxes for solid dynamics problems. Moreover, the introduction of suitable conjugate entropy variables enables the derivation of a symmetric system of hyperbolic equations, dual of that expressed in terms of conservation variables. Third, the new use of a tensor cross product [61] greatly facilitates the algebraic manipulations of expressions involving the co-factor of the deformation. Fourth, the development of a stabilised Petrov-Galerkin framework is presented for both systems of hyperbolic equations, that is, when expressed in terms of either conservation or entropy variables. As an example, a polyconvex Mooney-Rivlin material is used and, for completeness, the eigen-structure of the resulting system of equations is studied to guarantee the existence of real wave speeds. Finally, a series of numerical examples is presented in order to assess the robustness and accuracy of the new mixed methodology, benchmarking it against an ample spectrum of alternative numerical strategies, including implicit multi-field Fraeijs de Veubeke-Hu-Washizu variational type approaches and explicit cell and vertex centred Finite Volume schemes

    Relative age effect on national selection process in triathlon

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    El objetivo de este estudio fue analizar el efecto de la edad relativa (RAE) en el proceso de selección nacional de triatletas (n = 1321) durante las temporadas 2013-2015. La muestra fue divida por categorías y sexo. Cada una fue subdividida en 4 cuartiles según la fecha de nacimiento. Las diferencias fueron analizadas mediante la prueba no paramétrica Krustal-Wallis. Para la comparación múltiple se utilizó U de Mann Whitney. Los resultados mostraron que el rendimiento en las pruebas analizadas presentaba una mejor tendencia en aquellos deportistas nacidos en el primer cuartil del año para el sexo masculino. En esta línea, los atletas nacidos en la última parte mostraron un peor rendimiento general. Estos resultados fueron menos consistentes para el sexo femenino. Este trabajo ha puesto de manifiesto la influencia del RAE en los procesos de identificación de talentos y la estructura competitiva, sugiriendo su consideración en los procesos de selecciónThe aim of this study was to analyze the influence of relative age effect on the selection process in triathlon (n = 1321). The sample was divided by category and gender. Each category was allocated into four quartiles - based on date of birth according to the selection year. The Krustal-Wallis and Mann-Whitney test were used to analyze the intra-categorical and intra-gender differences. The results showed a better performance trend in those athletes that were born in the first quartile. In contrast, athletes that were born in the latter part of the year showed poorer overall performance and a lower score in the point scale. However, these results were less consistent for females. This work has shown a significant loss of potential triathlon talent due to the influence of RAE in the selection process and competitive structureEste trabajo ha sido financiado por la Secretaría de Investigación, Desarrollo e Innovación del Ministerio de Economía [DEP2012-32124

    Wavelength-codified fiber laser hydrogen detector

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    We report a scheme for an optical hydrogen detector that codifies the information in wavelength. The system is based on an erbium-doped fiber laser with two coupled cavities and a Palladium-coated tapered fiber within one of the laser cavities. The tapered fiber acts as the hydrogen-sensing element. When the sensing element is exposed to a hydrogen atmosphere, its attenuation decreases changing the cavity losses. This change leads the system to switch lasing from the wavelength of the auxiliary cavity to the characteristic wavelength of the cavity which contains the sensing element. The detection level can be shifted by adjusting the reflective elements of the cavity containing the sensing element

    Predicting the spread of epidemiological diseases by using a multi-objective algorithm

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    The epidemiological models are able to predict the spread of diseases, but a previous work on calibrating some involved parameters must be done. In this work, we propose a methodology to adjust those parameters based on solving a multi-objective optimization problem whose objective functions measure the accuracy of the model. More precisely, we have considered the Between-Countries Disease Spread model because it involves a set of countries taking into account the migratory movements among them. As a result, using some real data about the number of detected cases and the number of deaths for the Ebola virus disease, we have shown that the methodology is able to find a set of values for the parameters so that the model fits the outbreak spread for a set of countries
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