5,808 research outputs found

    NGC 6705 a young α\alpha-enhanced Open Cluster from OCCASO data

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    The stellar [α\alpha/Fe] abundance is sometimes used as a proxy for stellar age, following standard chemical evolution models for the Galaxy, as seen by different observational results. In this work we show that the Open Cluster NGC6705/M11 has a significant α\alpha-enhancement [α\alpha/Fe]>0.1>0.1 dex, despite its young age (∌\sim300 Myr), challenging the current paradigm. We use high resolution (R>65,000>65,000) high signal-to-noise (∌\sim70) spectra of 8 Red Clump stars, acquired within the OCCASO survey. We determine very accurate chemical abundances of several α\alpha elements, using an equivalent width methodology (Si, Ca and Ti), and spectral synthesis fits (Mg and O). We obtain [Si/Fe]=0.13±0.050.13\pm0.05, [Mg/Fe]=0.14±0.070.14\pm0.07, [O/Fe]=0.17±0.070.17\pm0.07, [Ca/Fe]=0.06±0.050.06\pm0.05 and [Ti/Fe]=0.03±0.030.03\pm0.03. Our results place these cluster within the group of young [α\alpha/Fe]-enhanced field stars recently found by several authors in the literature. The ages of our stars have an uncertainty of around 50 Myr, much more precise than for field stars. By integrating the cluster's orbit in several non-axisymmetric Galactic potentials, we establish the M11's most likely birth radius to lie between 6.8-7.5 kpc from the Galactic center, not far from its current position. With the robust Open Cluster age scale, our results prove that a moderate [α\alpha/Fe]-enhancement is no guarantee for a star to be old, and that not all α\alpha-enhanced stars can be explained with an evolved blue straggler scenario. Based on our orbit calculations, we further argue against a Galactic bar origin of M11.Comment: 10 pages, 6 figures, accepted in A&

    Lepton Number Violation from Colored States at the LHC

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    The possibility to search for lepton number violating signals at the Large Hadron Collider (LHC) in the colored seesaw scenario is investigated. In this context the fields that generate neutrino masses at the one-loop level are scalar and Majorana fermionic color-octets of SU(3). Due to the QCD strong interaction these states may be produced at the LHC with a favorable rate. We study the production mechanisms and decays relevant to search for lepton number violation signals in the channels with same-sign dileptons. In the simplest case when the two fermionic color-octets are degenerate in mass, one could use their decays to distinguish between the neutrino spectra. We find that for fermionic octets with mass up to about 1 TeV the number of same-sign dilepton events is larger than the standard model background indicating a promising signal for new physics.Comment: minor corrections, added reference

    Marcadores de la calidad y la genuinidad de aceites de sacha inchi extra virgen comerciales

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    This work tackles the study of the quality and authenticity of oils labeled and commercialized as extra virgin sacha inchi oil. Major and minor components as triglycerides, fatty acid methyl esters, tocopherols, sterols and hydrocarbons are determined as well as other physicochemical parameters (density, viscosity, acidity and peroxide value). The results showed that some of the commercialized oils do not fulfill the basic requirement established in the regulation such as the content of α-linolenic acid, higher than 44.7 or 55.0% in the cases of P. volubilis and P. huayllabambana, respectively. The calculated stigmasterol/campesterol ratio for genuine sacha inchi oils should be around 4, however not all commercial oils analyzed comply with this requirement. The presence of the flavons sesamin and sesamolin indicates the addition of compounds from sesame oils. Finally, some of the commercial oils showed to contain trans fatty acids although this was not accompanied by the sterene hydrocarbon presence.En este trabajo se aborda el estudio de la calidad y la genuinidad de los aceites etiquetados y comercializados como sacha inchi extra virgen. Se estudian los componentes mayoritarios como los triglicĂ©ridos y los Ă©steres metĂ­licos de ĂĄcidos grasos, componentes menores insaponificables (tocoferoles, esteroles e hidrocarburos) asĂ­ como otros parĂĄmetros fisicoquĂ­micos (densidad, viscosidad, acidez, perĂłxidos y estabilidad). Los resultados mostraron que algunos de los aceites comercializados no cumplĂ­an con el requisito bĂĄsico establecido en la normativa de tener un contenido en α-linolĂ©nico superior a 44,7 o 55,0% determinado para P. volubilis o P. huayllabambana respectivamente. La relaciĂłn estigmasterol/campesterol medida en aceites de sacha inchi genuinos es de alrededor de 4, y no todos los aceites comerciales analizados cumplĂ­an con este requisito. La presencia de las flavonas sesamina y sesamolina indica la adiciĂłn de compuestos procedentes de aceites de sĂ©samo. Por Ășltimo, algunos de los aceites comerciales estudiados, contenĂ­an ĂĄcidos grasos trans aunque no se detectĂł en ellos la presencia de hidrocarburos esteroideos

    Chiral Anomaly and CPT invariance in an implicit momentum space regularization framework

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    This is the second in a series of two contributions in which we set out to establish a novel momentum space framework to treat field theoretical infinities in perturbative calculations when parity-violating objects occur. Since no analytic continuation on the space-time dimension is effected, this framework can be particularly useful to treat dimension-specific theories. Moreover arbitrary local terms stemming from the underlying infinities of the model can be properly parametrized. We (re)analyse the undeterminacy of the radiatively generated CPT violating Chern-Simons term within an extended version of QED4QED_4 and calculate the Adler-Bardeen-Bell-Jackiw triangle anomaly to show that our framework is consistent and general to handle the subtleties involved when a radiative corretion is finite.Comment: 16 pages, LaTeX, version to appear in PR

    Experimental transition probabilities in NII lines

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    ProducciĂłn CientĂ­ficaThis work reports an extensive collection of 108 transition probabilities of NII lines in the visible spectral region, all of them measured in an emission experiment. Relative intensity measurements have been made on a pulsed discharge lamp and the absolute Aki values have been obtained by using the literature available data. Electron density and temperature range in this experiment from 0.2 to and from 17000 to 29000 K respectively. The first one has been simultaneously determined from two-wavelength interferometry and from the Stark broadening of HeI 471.3 nm, the second from Boltzmann-plot of NII lines and from NII/NI intensities ratios. The results are compared with the recent available literature.

Ministerio de EducaciĂłn y FormaciĂłn Profesional (grant PB-98-0356)Junta de Castilla y LeĂłn (grant VA23-99

    Controlling the size of two-dimensional polymer platelets for water-in-water emulsifiers

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    A wide range of biorelevant applications, partic- ularly in pharmaceutical formulations and the food and cosmetic industries, require the stabilization of two water-soluble blended components which would otherwise form incompatible biphasic mixtures. Such water-in-water emulsions can be achieved using Pickering stabilization, where two-dimensional (2D) nanomateri- als are particularly effective due to their high surface area. However, control over the shape and size of the 2D nanomaterials is challenging, where it has not yet been possible to examine chemically identical nanostructures with the same thickness but different surface areas to probe the size-effect on emulsion stabilization ability. Hence, the rationale design and realization of the full potential of Pickering water-in-water emulsion stabilization have not yet been achieved. Herein, we report for the first time 2D poly(lactide) platelets with tunable sizes (with varying coronal chemistry) and of uniform shape using a crystallization-driven self-assembly methodology. We have used this series of nanostructures to explore the effect of 2D platelet size and chemistry on the stabilization of a water-in-water emulsion of a poly(ethylene glycol) (PEG)/dextran mixture. We have demonstrated that cationic, zwitterionic, and neutral large platelets (ca. 3.7 × 10 6 nm 2 ) all attain smaller droplet sizes and more stable emulsions than their respective smaller platelets (ca. 1.2 × 105 nm 2 ). This series of 2D platelets of controlled dimensions provides an excellent exemplar system for the investigation of the effect of just the surface area on the potential effectiveness in a particular applicationPostprint (published version

    The Effective Lagrangian for Bulk Fermions in Models with Extra Dimensions

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    We compute the dimension 6 effective Lagrangian arising from the tree level integration of an arbitrary number of bulk fermions in models with warped extra dimensions. The coefficients of the effective operators are written in terms of simple integrals of the metric and are valid for arbitrary warp factors, with or without an infrared brane, and for a general Higgs profile. All relevant tree level fermion effects in electroweak and flavor observables can be computed using this effective Lagrangian.Comment: 22 pages. V2: typos corrected, matches published versio

    Multiple high-risk HPV genotypes are grouped by type and are associated with viral load and risk factors

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    Investigating whether high-risk human papillomavirus (HR-HPV) types tend to become grouped in a particular way and whether factors are associated with such grouping is important for measuring the real impact of vaccination. In total, 219 women proving positive for HPV as detected by real-time PCR were included in the study. Each sample was analysed for detecting and quantifying six viral types and the hydroxymethylbilane synthase gene. Multiple correspondence analysis led to determining grouping patterns for six HR-HPV types and simultaneous association with multiple variables and whether viral load was related to the coexistence of other viral types. Two grouping profiles were identified: the first included HPV-16 and HPV-45 and the second profile was represented by HPV-31, HPV-33 and HPV-58. Variables such as origin, contraceptive method, births and pregnancies, educational level, healthcare affiliation regime, atypical squamous cells of undetermined significance and viral load were associated with these grouping profiles. Different socio-demographic characteristics were found when coinfection occurred by phylogenetically related HPV types and when coinfection was due to non-related types. Biological characteristics, the number of viral copies, temporality regarding acquiring infection and competition between viral types could influence the configuration of grouping patterns. Characteristics related to women and HPV, influence such interactions between coexisting HPV types reflecting the importance of their evaluation. Copyright © Cambridge University Press 2017
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