1,729 research outputs found

    Development and characterization of 13 SSR markers for an endangered insular juniper (Juniperus cedrus Webb & Berth.)

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    We report the development of 13 microsatellite markers (SSR) for the Canarian endemic juniper, Juniperus cedrus. Evaluated in a set of 28 individuals sampled on the island of Tenerife, all markers showed polymorphism and displayed 56 alleles. The number of alleles ranged from 2 to 8, with an average of 4.31 alleles per locus. This set of SSR markers will be very useful in further studies on the population genetics or phylogeography of this endangered species, leading to more appropriate and successful management

    Outer Regions of the Milky Way

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    With the start of the Gaia era, the time has come to address the major challenge of deriving the star formation history and evolution of the disk of our MilkyWay. Here we review our present knowledge of the outer regions of the Milky Way disk population. Its stellar content, its structure and its dynamical and chemical evolution are summarized, focussing on our lack of understanding both from an observational and a theoretical viewpoint. We describe the unprecedented data that Gaia and the upcoming ground-based spectroscopic surveys will provide in the next decade. More in detail, we quantify the expect accuracy in position, velocity and astrophysical parameters of some of the key tracers of the stellar populations in the outer Galactic disk. Some insights on the future capability of these surveys to answer crucial and fundamental issues are discussed, such as the mechanisms driving the spiral arms and the warp formation. Our Galaxy, theMilkyWay, is our cosmological laboratory for understanding the process of formation and evolution of disk galaxies. What we learn in the next decades will be naturally transferred to the extragalactic domain.Comment: 22 pages, 10 figures, Invited review, Book chapter in "Outskirts of Galaxies", Eds. J. H. Knapen, J. C. Lee and A. Gil de Paz, Astrophysics and Space Science Library, Springer, in pres

    Darboux points and integrability of homogeneous Hamiltonian systems with three and more degrees of freedom

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    We consider natural complex Hamiltonian systems with nn degrees of freedom given by a Hamiltonian function which is a sum of the standard kinetic energy and a homogeneous polynomial potential VV of degree k>2k>2. The well known Morales-Ramis theorem gives the strongest known necessary conditions for the Liouville integrability of such systems. It states that for each kk there exists an explicitly known infinite set \scM_k\subset\Q such that if the system is integrable, then all eigenvalues of the Hessian matrix V''(\vd) calculated at a non-zero \vd\in\C^n satisfying V'(\vd)=\vd, belong to \scM_k. The aim of this paper is, among others, to sharpen this result. Under certain genericity assumption concerning VV we prove the following fact. For each kk and nn there exists a finite set \scI_{n,k}\subset\scM_k such that if the system is integrable, then all eigenvalues of the Hessian matrix V''(\vd) belong to \scI_{n,k}. We give an algorithm which allows to find sets \scI_{n,k}. We applied this results for the case n=k=3n=k=3 and we found all integrable potentials satisfying the genericity assumption. Among them several are new and they are integrable in a highly non-trivial way. We found three potentials for which the additional first integrals are of degree 4 and 6 with respect to the momenta.Comment: 54 pages, 1 figur

    Nuevo mĂ©todo de preparaciĂłn de soforosa y kojibiosa a partir de 1,6-anhidro-β-D-glucopiranosa

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    A new method for the preparation of the dissaccharides sophorose and kojibiose by theatment of the 1,6-anhydro-β-D-glucopyranose in DMFHCl 0,03 N under mild conditions is reported.Se describe un nuevo método para la preparación de los disacáridos soforosa y kojibiosa por tratamiento en condiciones suaves de 1,6-anhidro-β-D-glucopiranosa en DMF-HCl 0,03 N

    Oligomerización dé aldohexosas en DMF-HCl. Estudio del mecanismo

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    On the basis of the obtained data for acid catalysed oligomerization reactions of D-glucose, D-galactose, D-manose and L-rhamnose in DMFHCl, mechanistic schemes are proposed.Basándose en los datos obtenidos en reacciones de oligomerización catalizadas por ácidos de D-glucosa, D-galactosa, D-manosa y L-rhamnosa en DMF-HGl se proponen esquemas mecanísticos para cada caso

    The Proteome of Biologically Active Membrane Vesicles from Piscirickettsia salmonis LF-89 Type Strain Identifies Plasmid-Encoded Putative Toxins

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    Indexación: Scopus.Piscirickettsia salmonis is the predominant bacterial pathogen affecting the Chilean salmonid industry. This bacterium is the etiological agent of piscirickettsiosis, a significant fish disease. Membrane vesicles (MVs) released by P. salmonis deliver several virulence factors to host cells. To improve on existing knowledge for the pathogenicity-associated functions of P. salmonis MVs, we studied the proteome of purified MVs from the P. salmonis LF-89 type strain using multidimensional protein identification technology. Initially, the cytotoxicity of different MV concentration purified from P. salmonis LF-89 was confirmed in an in vivo adult zebrafish infection model. The cumulative mortality of zebrafish injected with MVs showed a dose-dependent pattern. Analyses identified 452 proteins of different subcellular origins; most of them were associated with the cytoplasmic compartment and were mainly related to key functions for pathogen survival. Interestingly, previously unidentified putative virulence-related proteins were identified in P. salmonis MVs, such as outer membrane porin F and hemolysin. Additionally, five amino acid sequences corresponding to the Bordetella pertussis toxin subunit 1 and two amino acid sequences corresponding to the heat-labile enterotoxin alpha chain of Escherichia coli were located in the P. salmonis MV proteome. Curiously, these putative toxins were located in a plasmid region of P. salmonis LF-89. Based on the identified proteins, we propose that the protein composition of P. salmonis LF-89 MVs could reflect total protein characteristics of this P. salmonis type strain. © 2017 Oliver, Hernández, Tandberg, Valenzuela, Lagos, Haro, Sánchez, Ruiz, Sanhueza-Oyarzún, Cortés, Villar, Artigues, Winther-Larsen, Avendaño-Herrera and Yáñez.https://www.frontiersin.org/articles/10.3389/fcimb.2017.00420/ful

    Modelling the hydrodynamic conditions associated with Dinophysis blooms in Galicia (NW Spain)

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    The northwestern Iberian coast (Galician RĂ­as and shelf) is frequently affected by toxic harmful algal blooms (HABs) (mainly Dinophysis spp.), leading to lengthy harvesting closures in a region where aquaculture has a strong socioeconomic impact. The project ASIMUTH (http://www.asimuth.eu) aimed to develop forecasting capabilities to warn of impending HABs along the European Atlantic coast. Simulations with the ROMS model (hydrodynamical and ecological simulations complemented with Lagrangian particle tracking simulations) of the Galician coastal circulation have been performed in the framework of the ASIMUTH project to characterize and forecast oceanographic conditions before and during HAB periods. In this work, we present the Galician ASIMUTH forecast system and demonstrate its skill in predicting HAB transport and its usefulness to provide assessment for the management of the areas affected by toxic outbreaks. Experience gained during DSP events in 2005 and 2013 is shown. We also describe the Galician pilot HAB bulletins, aimed at distributing forecasts of HAB events that might induce closures of harvesting areas or, when the areas are already closed, at giving information on forthcoming oceanographic conditions that could favour or hamper the opening of an area. Our results show that the model forecasts and the bulletins can provide early warning of the risk of Dinophysis spp. events and the risk of closures linked to the presence of DSP toxins above regulatory levels in harvesting areas.VersiĂłn del editor3,083
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