The long Galactic bar as seen by UKIDSS Galactic Plane Survey

Over the last decade there have been a series of results supporting the hypothesis of the existence of a long thin bar in the Milky Way with a half-length of 4.5 kpc and a position angle of around 45 deg. This is apparently a very different structure from the triaxial bulge of the Galaxy, which is thicker and shorter and dominates the star counts at |l|<10 deg. In this paper, we analyse the stellar distribution in the inner Galaxy to see if there is clear evidence for two triaxial or bar-like structures in the Milky Way. By using the red-clump population as a tracer of Galactic structure, we determine the apparent morphology of the inner Galaxy. Deeper and higher spatial resolution NIR photometry from the UKIDSS Galactic Plane Survey allows us to use in-plane data even at the innermost Galactic longitudes, a region where the source confusion is a dominant effect that makes it impossible to use other NIR databases such as 2MASS or TCS-CAIN. We show that results previously obtained with using the red-clump giants are confirmed with the in-plane data from UKIDSS GPS. There are two different structures coexisting in the inner Galactic plane: one with a position angle of 23.60+-2.19 deg that can be traced from the Galactic Centre up to l=10 deg (the Galactic bulge), and other with a larger position angle of 42.44+-2.14 deg, that ends around l=28 deg (the long Galactic bar).Comment: (8 pages, 14 figures, accepted for publication in A&A

A boxy bulge in the Milky Way. Inversion of the stellar statistics equation with 2MASS data

Inverting the stellar statistics equation from 2MASS star counts, we obtain the 3D density distribution of the Galactic bulge as well as its luminosity function in the K-band. This results in a boxy bulge with axial ratios 1:0.5:0.4 and a major axis angle with respect to the Sun-galactic center of $20^\circ-35^\circ$.Comment: 5 pages, accepted to be published in A&

Tracing the long bar with red-clump giants

Over the last decade a series of results have lent support to the hypothesis of the existence of a long thin bar in the Milky Way with a half-length of 4.5 kpc and a position angle of around 45 deg. This is apparently a very different structure from the triaxial bulge of the Galaxy. In this paper, we analyse the stellar distribution in the inner 4 kpc of the Galaxy to see if there is clear evidence for two triaxial or barlike structures, or whether there is only one. By using the red-clump population as a tracer of the structure of the inner Galaxy we determine the apparent morphology of the inner Galaxy. Star counts from 2MASS are used to provide additional support for this analysis. We show that there are two very different large-scale triaxial structures coexisting in the inner Galaxy: a long thin stellar bar constrained to the Galactic plane (|b|<2 deg) with a position angle of 43.1 +- 1.8 deg, and a distinct triaxial bulge that extends to at least |b|<7.5 deg with a position angle of 12.6 +- 3.2 deg. The scale height of the bar source distribution is around 100 pc, whereas for the bulge the value of this parameter is five times larger.Comment: 16 pages, 35 figures, accepted for publication in A&

Composición química y acidez de la lluvia: doce años de observaciones en Cuba

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Reaffirming the connection between the Galactic stellar warp and the Canis Major overdensity

We perform a critical re-analysis and discussion of recent results presented in the literature which interpret the CMa overdensity as the signature of an accreting dwarf galaxy or a new substructure within the Galaxy. Several issues are addressed. We show that arguments against the ``warp'' interpretation are based on an erroneous perception of the Milky Way. There is nothing anomalous with colour--magnitude diagrams on opposite sides of the average warp mid-plane being different. We witnessed the rise and fall of the blue plume population, first attributed to young stars in a disrupting dwarf galaxy and now discarded as a normal disc population. Similarly, there is nothing anomalous in the outer thin+thick disc metallicities being low (-1<[Fe/H]<-0.5), and spiral arms (as part of the thin disc) should, and do, warp. Most importantly, we show unambiguously that, contrary to previous claims, the warp produces a stellar overdensity that is distance-compatible with that observed in CMa.The CMa over-density remains fully accounted for in a first order approach by Galactic models without new substructures. Given the intrinsic uncertainties (concerning the properties of the warp, flare and disc cutoff, the role of extinction and degeneracy), minor deviations with respect to these models are not enough to support the hypothesis of an accreted dwarf galaxy or new substructure within the Milky Way disc.Comment: A&A Letter, accepted, 4 pages, 3 figure

El papel del voluntariado universitario en la creación de una comunidad de aprendizaje.

La comunicación que presentamos describe el proceso de participación del voluntariado universitario en la comunidad de aprendizaje CEIP Albolafia de Córdoba. Dado que el papel del voluntariado en este tipo de experiencias es clave para la puesta en práctica de las actuaciones transformadoras, nuestra tarea ha estado centrada en articular la presencia de un grupo de alumnos y alumnas en el centro educativo. Por ello consideramos de interés valorar sus conocimientos previos sobre el tema, sus deseos de transformación social y sus motivaciones para participar en este proyecto. La información obtenida ha permitido reformular las actuaciones en relación a la formación, el compromiso y la participación en la comunidad de aprendizaje

Mimicking the extracellular matrix – a biomaterials approach to inhibit tissue fibrosis

Epithelial tissue is marked by the presence of a specialized, highly cross-linked, sheet-like extracellular matrix, the basement membrane. Tissue-invasive events, such as the epithelial-to-mesenchymal transition (EMT) - a key event in gastrulation, tissue fibrosis and cancer metastasis – are characterized by irreversible structural changes of the basement membrane through proteolytic processing by matrix metalloproteinases (MMPs). We have recently reported a previously unidentified laminin fragment that is released during EMT by MMP2 and that modulates key EMT-signalling pathways. Specifically, interaction of the laminin fragment with α3β1-integrin triggers the down-regulation of MMP2 expression, thereby constituting a cell-basement membrane-cell feedback mechanism. Inhibiting MMPs has been proposed as a strategy to prevent pathological cell migration and basement membrane breakdown in the course of EMT. Here, we explore this cell-matrix-cell feedback mechanism to target pathological EMT in the course of tissue fibrosis. We present an electrospun biomaterial that is functionalized with the recombinant laminin fragment and that can be directly interfaced with epithelial tissue to interfere with EMT pathways and inhibit MMP2 expression and activity in vitro and in vivo. We demonstrate how interaction of the functionalized synthetic membrane with peritoneal tissue inhibits mesothelial EMT in a mouse model of TGFβ-induced peritoneal fibrosis by decreasing active MMP2 levels, and propose a mechanism of how the laminin fragment acts downstream of α3β1-integrin in epithelial cells, after it is released from the basement membrane

Submarine landslide morphometrics and slope failure dynamics along a mixed carbonate-siliciclastic margin, north-eastern Australia

Comparatively little work has been carried out on the morphology and distribution of submarine landslides on mixed carbonate-siliciclastic margins. The morphometric analysis of 84 open slope submarine landslides on the Great Barrier Reef (GBR) margin of north-eastern Australia provides useful insights into slope failure dynamics and frequency distribution of landslides on mixed margins. Our analysis has revealed that the slope area affected by failures (12.6% of the margin) is similar to siliciclastic-dominated passive margins, although the total volume of remobilized sediment (73 km3) is comparatively small. Landslide scars lie at shallower depths to the south of the margin (mean of 576 m vs 1517 m to the north) and there is good correlation between the depth at origin and depth at termination for the GBR landslides. The cumulative frequency distribution of volume, area and total length of the GBR landslides does not fit to common distributions (e.g., power law, logarithmic or exponential) for the entire dataset. Still, the cumulative frequency distribution of landslide dimensions can be statistically explained either by a power law similar to other passive margins, or by a lognormal distribution similar to some siliciclastic margins. Morphometric characteristics, such as the volume of sediment released per unit width and the probability function of volume distribution suggest that slope failures mainly involved relatively unconsolidated sediments. We find that the disintegration by debris flows was the dominant process along the entire GBR margin and that their spreading efficiency and mobility was relatively low. Margin stratigraphy, fluid overpressure at the base of the slope, and detachment surfaces at the boundary between different lithologies that separate sedimentary cycles may have preconditioned the slope to fail. This compilation provides a robust morphometric framework that allows comparison with existing and future slope failure databases, and lays the foundation for performing numerical simulations to assess the landslide-generated tsunamigenic hazards along the GBR margin