1,553 research outputs found

    La biblioteca de formació del professorat d'Elx

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    S'explica una breu història de la B-CD de Formació del Professorat d'Elx des del seu naixement, fa 30 anys, com a Biblioteca del CEP d'Elx, fins a la actualitat com a extensió del CEFIRE d'Alacant. Mantenint una missió invariable al llarg de tots aquests anys, que és satisfer les necessitats formatives i in formatives de tota persona relacionada amb el món educatiu. És una biblioteca especialitzada en educació i didàctica pel contingut dels seus fons i pública perquè està oberta a totes les persones que sol·liciten aquest tipus d'informació. S'expliquen de forma detallada tot elsserveis que ofereix als seus usuaris tant presencials com virtual

    Extended stellar populations in Ultra-Faint Dwarf galaxies

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    The possible existence of stellar halos in low-mass galaxies is being intensely discussed nowadays after some recent discoveries of stars located in the outskirts of dwarf galaxies of the Local Group. RR Lyrae stars can be used to identify the extent of these structures, taking advantage of the minimization of foreground contamination they provide. In this work we use RR Lyrae stars obtained from Gaia DR3, DES, ZTF, and Pan-STARRS1 to explore the outskirts of 4545 ultra-faint dwarf galaxies. We associate the stars with a host galaxy based on their angular separations, magnitudes and proper motions. We find a total of 120120 RR Lyrae stars that belong to 2121 different galaxies in our sample. We report seven new RR Lyrae stars in six ultra-faint dwarf galaxies (Hydrus I, Ursa Major I, Ursa Major II, Grus II, Eridanus II and Tucana II). We found a large number of new possible members in Bootes I and Bootes III as well, but some of them may actually belong to the nearby Sagittarius stream. Adding to our list of 120120 RR Lyrae stars the observations of other ultra-faint dwarf galaxies that were out of the reach of our search, we find that at least 1010 of these galaxies have RR Lyrae stars located at farther distances than 44 times their respective half-light radius, which implies that at least 33%33\% of the 30 ultra-faint dwarfs with RR Lyrae star population have extended stellar populations.Comment: 22 pages. Accepted for publication in A

    Mutational Patterns Associated with the 69 Insertion Complex in Multi-drug-resistant HIV-1 Reverse Transcriptase that Confer Increased Excision Activity and High-level Resistance to Zidovudine

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    Human immunodeficiency virus type 1 (HIV-1) strains having dipeptide insertions in the fingers subdomain and other drug resistance-related mutations scattered throughout their reverse transcriptase (RT)-coding region show high-level resistance to zidovudine (AZT) and other nucleoside analogues. Those phenotypic effects have been correlated with their increased ATP-dependent phosphorolytic activity on chain-terminated primers. Mutations T69S and T215Y and a dipeptide insertion (i.e. Ser-Ser) between positions 69 and 70 are required to achieve low-level resistance to thymidine analogues. However, additional amino acid substitutions are necessary to achieve the high-level phenotypic resistance to AZT shown by clinical HIV isolates carrying a dipeptide insertion in their RT-coding region. In order to identify those mutations that contribute to resistance in the sequence context of an insertion-containing RT derived from an HIV clinical isolate (designated as SS RT), we expressed and purified a series of chimeric enzymes containing portions of the wild-type or SS RT sequences. ATP-mediated excision activity measurements using AZT- and stavudine (d4T)-terminated primers and phenotypic assays showed that molecular determinants of high-level resistance to AZT were located in the fingers subdomain of the polymerase. Further studies, using recombinant RTs obtained by site-directed mutagenesis, revealed that M41L, A62V and in a lesser extent K70R, were the key mutations that together with T69S, T215Y and the dipeptide insertion conferred high levels of ATP-dependent phosphorolytic activity on AZT and d4T-terminated primers. Excision activity correlated well with AZT susceptibility measurements, and was consistent with phenotypic resistance to d4T. Structural analysis of the location of the implicated amino acid substitutions revealed a coordinated effect of M41L and A62V on the positioning of the β3–β4 hairpin loop, which plays a key role in the resistance mechanismThis work was supported in part by FIPSE (grant 36523/05) and Fondo de Investigación Sanitaria (through “Red Temática Cooperativa de Investigación en SIDA” G03/173). In addition, work in Madrid was supported by grant BIO2003/01175 (Ministerio de Educación y Ciencia) and an institutional grant from Fundación Ramón Areces. Grant BMC2003/2148 (Ministerio de Educación y Ciencia) (to M. A.M.) is also acknowledgedPeer reviewe

    Vimentin filament organization and stress sensing depend on its single cysteine residue and zinc binding

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    17 pág., 10 figs.The vimentin filament network plays a key role in cell architecture and signalling, as well as in epithelial–mesenchymal transition. Vimentin C328 is targeted by various oxidative modifications, but its role in vimentin organization is not known. Here we show that C328 is essential for vimentin network reorganization in response to oxidants and electrophiles, and is required for optimal vimentin performance in network expansion, lysosomal distribution and aggresome formation. C328 may fulfil these roles through interaction with zinc. In vitro, micromolar zinc protects vimentin from iodoacetamide modification and elicits vimentin polymerization into optically detectable structures; in cells, zinc closely associates with vimentin and its depletion causes reversible filament disassembly. Finally, zinc transportdeficient human fibroblasts show increased vimentin solubility and susceptibility to disruption, which are restored by zinc supplementation. These results unveil a critical role of C328 in vimentin organization and open new perspectives for the regulation of intermediate filaments by zinc. DOI: 10.1038/ncomms8287 OPEN 1This work was supported by grants SAF2012–36519, MINECO, Spain and RD12/0013/0008, ISCIII to D.P.-S., and CTQ2012–32025, MINECO, y CAM MHIT S2010/BMD-2353 to F.J.C. C.L.O. and B.G. have been recipients of fellowships BES-2010–033718 and BES-2007–15806, respectively (FPI, MINECO). We acknowledge support from COST Action CM1001.Peer reviewe

    The ISLANDS project I: Andromeda XVI, An Extremely Low Mass Galaxy not Quenched by Reionization

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    Based on data aquired in 13 orbits of HST time, we present a detailed evolutionary history of the M31 dSph satellite Andromeda XVI, including its life-time star formation history, the spatial distribution of its stellar populations, and the properties of its variable stars. And XVI is characterized by prolonged star formation activity from the oldest epochs until star formation was quenched ~6 Gyr ago, and, notably, only half of the mass in stars of And XVI was in place 10 Gyr ago. And XVI appears to be a low mass galaxy for which the early quenching by either reionization or starburst feedback seems highly unlikely, and thus, is most likely due to an environmental effect (e.g., an interaction), possibly connected to a late infall in the densest regions of the Local Group. Studying the star formation history as a function of galactocentric radius, we detect a mild gradient in the star formation history: the star formation activity between 6 and 8 Gyr ago is significantly stronger in the central regions than in the external regions, although the quenching age appears to be the same, within 1 Gyr. We also report the discovery of 9 RR Lyrae stars, 8 of which belong to And XVI. The RR Lyrae stars allow a new estimate of the distance, (m-M)0= 23.72+/-0.09 mag, which is marginally larger than previous estimates based on the tip of the red giant branch.Comment: Accepted for publication on Ap

    The Diachronic Spanish Sonnet Corpus (DISCO): TEI and Linked Open Data Encoding, Data Distribution and Metrical Findings

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    We present a corpus covering 4094 sonnets in Spanish by 1204 authors, from the 15th to the 19th centuries, extracted from HTML sources. The corpus was encoded in TEI. Author metadata not available in a standardized format in the sources were systematically retrieved or inferred from the sources and added to the corpus, e.g. author gender or VIAF IDs. RDFa was used to render TEI semantics in the Linked Open Data paradigm. Scansion was annotated automatically with the ADSO Scansion System. Enjambment was annotated automatically with our enjambment detection tool (ANJA). Stanza types were also annotated. The corpus covers both canonical and non-canonical authors, from Europe and Latin America. The range of authors and periods, the use of both TEI and RDFa for interoperability, and the combination of metrical and enjambment annotations goes beyond previously available digital resources for the study of poetry in Spanish. This corpus is a contribution within an area where digital resources are scarce. We also present some literary analysis results that illustrate the type of research questions that can be answered with the corpus

    The O-mannosylation and production of recombinant APA (45/47 KDa) protein from Mycobacterium tuberculosis in Streptomyces lividans is affected by culture conditions in shake flasks

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    <p>Abstract</p> <p>Background</p> <p>The Ala-Pro-rich <it>O</it>-glycoprotein known as the 45/47 kDa or APA antigen from <it>Mycobacterium tuberculosis </it>is an immunodominant adhesin restricted to mycobacterium genus and has been proposed as an alternative candidate to generate a new vaccine against tuberculosis or for diagnosis kits. In this work, the recombinant <it>O</it>-glycoprotein APA was produced by the non-pathogenic filamentous bacteria <it>Streptomyces lividans</it>, evaluating three different culture conditions. This strain is known for its ability to produce heterologous proteins in a shorter time compared to <it>M. tuberculosis</it>.</p> <p>Results</p> <p>Three different shake flask geometries were used to provide different shear and oxygenation conditions; and the impact of those conditions on the morphology of <it>S. lividans </it>and the production of rAPA was characterized and evaluated. Small unbranched free filaments and mycelial clumps were found in baffled and coiled shake flasks, but one order of magnitude larger pellets were found in conventional shake flasks. The production of rAPA is around 3 times higher in small mycelia than in larger pellets, most probably due to difficulties in mass transfer inside pellets. Moreover, there are four putative sites of <it>O</it>-mannosylation in native APA, one of which is located at the carboxy-terminal region. The carbohydrate composition of this site was determined for rAPA by mass spectrometry analysis, and was found to contain different glycoforms depending on culture conditions. Up to two mannoses residues were found in cultures carried out in conventional shake flasks, and up to five mannoses residues were determined in coiled and baffled shake flasks.</p> <p>Conclusions</p> <p>The shear and/or oxygenation parameters determine the bacterial morphology, the productivity, and the <it>O</it>-mannosylation of rAPA in <it>S. lividans</it>. As demonstrated here, culture conditions have to be carefully controlled in order to obtain recombinant <it>O</it>-glycosylated proteins with similar "quality" in bacteria, particularly, if the protein activity depends on the glycosylation pattern. Furthermore, it will be an interesting exercise to determine the effect of shear and oxygen in shake flasks, to obtain evidences that may be useful in scaling-up these processes to bioreactors. Another approach will be using lab-scale bioreactors under well-controlled conditions, and study the impact of those on rAPA productivity and quality.</p

    RR Lyrae mid-infrared Period-Luminosity-Metallicity and Period-Wesenheit-Metallicity relations based on Gaia DR3 parallaxes

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    We present new empirical infrared Period-Luminosity-Metallicity (PLZ) and Period-Wesenheit-Metallicity (PWZ) relations for RR Lyrae based on the latest Gaia EDR3 parallaxes. The relations are provided in the WISE W1W1 and W2W2 bands, as well as in the W(W1,VW1)W(W1, V - W1) and W(W2,VW2)W(W2, V - W2) Wesenheit magnitudes. The relations are calibrated using a very large sample of Galactic halo field RR Lyrae stars with homogeneous spectroscopic [Fe/H] abundances (over 1,000 stars in the W1W1 band), covering a broad range of metallicities (2.5[Fe/H]0.0-2.5 \lesssim \textrm{[Fe/H]} \lesssim 0.0). We test the performance of our PLZ and PWZ relations by determining the distance moduli of both galactic and extragalactic stellar associations: the Sculptor dwarf spheroidal galaxy in the Local Group (finding μˉ0=19.47±0.06\bar{\mu}_{0}=19.47 \pm 0.06), the Galactic globular clusters M4 (μˉ0=11.16±0.05\bar{\mu}_{0}=11.16 \pm 0.05) and the Reticulum globular cluster in the Large Magellanic Cloud (μˉ0=18.23±0.06\bar{\mu}_{0}=18.23 \pm 0.06). The distance moduli determined through all our relations are internally self-consistent (within \lesssim 0.05 mag) but are systematically smaller (by \sim 2-3σ\sigma) than previous literature measurements taken from a variety of methods/anchors. However, a comparison with similar recent RR Lyrae empirical relations anchored with EDR3 likewise shows to varying extents a systematically smaller distance modulus for PLZ/PWZ RR Lyrae relations.Comment: Accepted by ApJ, 14 pages, 5 Figures, 2 Table
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