3,301 research outputs found

    Deslizamiento de leintz gatzaga: instrumentación geotécnica y monitorización del movimiento con técnicas terrestres y espaciales.

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    La inestabilidad de ladera que afecta a la villa de Leintz Gatzaga (Gipuzkoa) y su entorno ha producido desde hace siglos daños estructurales en viviendas, muros y viales, que van desde moderados a intensos. Esto ha obligado a ejecutar diferentes actuaciones de reparación y consolidación. Se realiza en este trabajo una discusión geológico/geotécnica de los datos disponibles sobre el deslizamiento que afecta a la ladera, así como de los resultados obtenidos a partir de su monitorización con inclinómetros, piezómetros y ?surómetros en lo

    High-velocity collimated outflows in planetary nebulae: NGC 6337, He 2-186, and K 4-47

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    We have obtained narrow-band images and high-resolution spectra of the planetary nebulae NGC 6337, He 2-186, and K 4-47, with the aim of investigating the relation between their main morphological components and several low-ionization features present in these nebulae. The data suggest that NGC 6337 is a bipolar PN seen almost pole on, with polar velocities higher than 200 km/s. The bright inner ring of the nebula is interpreted to be the "equatorial" density enhancement. It contains a number of low-ionization knots and outward tails that we ascribe to dynamical instabilities leading to fragmentation of the ring or transient density enhancements due to the interaction of the ionization front with previous density fluctuations in the ISM. The lobes show a pronounced point-symmetric morphology and two peculiar low-ionization filaments whose nature remains unclear. The most notable characteristic of He 2-186 is the presence of two high-velocity (higher than 135 km/s) knots from which an S-shaped lane of emission departs toward the central star. K 4-47 is composed of a compact core and two high-velocity, low-ionization blobs. We interpret the substantial broadening of line emission from the blobs as a signature of bow shocks, and using the modeling of Hartigan, Raymond, & Hartman (1987), we derive a shock velocity of 150 km/s and a mild inclination of the outflow on the plane of the sky. We discuss possible scenarios for the formation of these nebulae and their low-ionization features. In particular, the morphology of K 4-47 hardly fits into any of the usually adopted mass-loss geometries for single AGB stars. Finally, we discuss the possibility that point-symmetric morphologies in the lobes of NGC 6337 and the knots of He 2-186 are the result of precessing outflows from the central stars.Comment: 16 pages plus 7 figures, ApJ accepted. Also available at http://www.iac.es/publicaciones/preprints.htm

    Synthesis of Selenium-Quinone Hybrid Compounds with Potential Antitumor Activity via Rh-Catalyzed C-H Bond Activation and Click Reactions

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    In continuation of our quest for new redox-modulating catalytic antitumor molecules, selenium-containing quinone-based 1,2,3-triazoles were synthesized using rhodium-catalyzed C-H bond activation and click reactions. All compounds were evaluated against five types of cancer cell lines: HL-60 (human promyelocytic leukemia cells), HCT-116 (human colon carcinoma cells), SF295 (human glioblastoma cells), NCIH-460 (human lung cells) and PC3 (human prostate cancer cells). Some compounds showed good activity with IC50 values below 1 µM. The cytotoxic potential of the naphthoquinoidal derivatives was also evaluated in non-tumor cells, exemplified by L929 cells. Overall, these compounds represent promising new lead derivatives and stand for a new class of chalcogenium-containing derivatives with potential antitumor activity

    Dark Matter Candidates: A Ten-Point Test

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    An extraordinarily rich zoo of non-baryonic Dark Matter candidates has been proposed over the last three decades. Here we present a 10-point test that a new particle has to pass, in order to be considered a viable DM candidate: I.) Does it match the appropriate relic density? II.) Is it {\it cold}? III.) Is it neutral? IV.) Is it consistent with BBN? V.) Does it leave stellar evolution unchanged? VI.) Is it compatible with constraints on self-interactions? VII.) Is it consistent with {\it direct} DM searches? VIII.) Is it compatible with gamma-ray constraints? IX.) Is it compatible with other astrophysical bounds? X.) Can it be probed experimentally?Comment: 29 pages, 12 figure

    Ultrastructure of the Interlamellar Membranes of the Nacre of the Bivalve Pteria hirundo, Determined by Immunolabelling

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    The current model for the ultrastructure of the interlamellar membranes of molluscan nacre imply that they consist of a core of aligned chitin fibers surrounded on both sides by acidic proteins. This model was based on observations taken on previously demineralized shells, where the original structure had disappeared. Despite other earlier claims, no direct observations exist in which the different components can be unequivocally discriminated. We have applied different labeling protocols on non-demineralized nacreous shells of the bivalve Pteria. With this method, we have revealed the disposition and nature of the different fibers of the interlamellar membranes that can be observed on the surface of the nacreous shell of the bivalve Pteria hirundo by high resolution scanning electron microscopy (SEM). The minor chitin component consists of very thin fibers with a high aspect ratio and which are seemingly disoriented. Each fiber has a protein coat, which probably forms a complex with the chitin. The chitin-protein-complex fibers are embedded in an additional proteinaceous matrix. This is the first time in which the sizes, positions and distribution of the chitin fibers have been observed in situ.AJOM was financed by a PhD Grant of the FPI program from the Spanish Ministerio de Ciencia e Innovación; TCB's PhD Grant belonged to the FPU Program of the same Ministry. AJOM and AGC were supported by Projects CGL2010-20748-C02-01 and CGL2013-48247-P of the mentioned Ministry, and RNM6433 of the Consejería de Economía, Innovación y Ciencia of the Junta de Andalucía. The European COST Action TD0903 contributed via two Short Term Scientific Missions to AJOM in FM's lab in Dijon

    Scattering of 8He on 208Pb at 22 MeV

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    The skin nucleus 8He is investigated by measuring the angular distribution of the elasticly scattered 8He and the 6,4He fragments produced in the collision with a 208Pb target at 22 MeV, just above the Coulomb barrier. The experiment was carried out at SPIRAL/GANIL in 2010. Here we present preliminary results for the elastic scattering

    Charged-Higgs phenomenology in the Aligned two-Higgs-doublet model

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    The alignment in flavour space of the Yukawa matrices of a general two-Higgs-doublet model results in the absence of tree-level flavour-changing neutral currents. In addition to the usual fermion masses and mixings, the aligned Yukawa structure only contains three complex parameters, which are potential new sources of CP violation. For particular values of these three parameters all known specific implementations of the model based on discrete Z_2 symmetries are recovered. One of the most distinctive features of the two-Higgs-doublet model is the presence of a charged scalar. In this work, we discuss its main phenomenological consequences in flavour-changing processes at low energies and derive the corresponding constraints on the parameters of the aligned two-Higgs-doublet model.Comment: 46 pages, 19 figures. Version accepted for publication in JHEP. References added. Discussion slightly extended. Conclusions unchange

    Animal housing in hot climates : a multidisciplinary view

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    Since energy balance, thermoregulation and environmental aspects of "high producingdairy cows" were thoroughly studied (Brody, 1945; Flatt et al., 1969; Berman et al., 1985),the high producing dairy cow more than doubled production with a body weight increase of about 10-20% which imposed a three fold increase of heat increment (Kadzer et al., 2002).There is an apparent world wide lack of realization that changes in the physical and geneticconstitution of cows may have affected their thermoregulatory capability in hot climate forexample, blood plasma fluctuation in volume and constituents (Maltz et al, 1994); as wellas how they cope with heat stress (Kadzer et al., 2002). As a result, research inthermoregulation in relation to housing facilities and cooling management falls behind(except for few exceptions seen below) the aggressive selection for increased productionthat livestock undergoes as well as changes in technology and housing materials. Therefore,most of the improvements in this area are farmers and designers initiatives based oncommon sense and experience.peer-reviewe

    Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

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    Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson
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