3,594 research outputs found

    The bivariate gas-stellar mass distributions and the mass functions of early- and late-type galaxies at z∼0z\sim0

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    We report the bivariate HI- and H2_2-stellar mass distributions of local galaxies in addition of an inventory of galaxy mass functions, MFs, for HI, H2_2, cold gas, and baryonic mass, separately into early- and late-type galaxies. The MFs are determined using the HI and H2_2 conditional distributions and the galaxy stellar mass function, GSMF. For the conditional distributions we use the compilation presented in Calette et al. 2018. For determining the GSMF from M∗∼3×107M_{\ast}\sim3\times10^{7} to 3×10123\times10^{12} M⊙M_{\odot}, we combine two spectroscopic samples from the SDSS at the redshift range 0.0033<z<0.20.0033<z<0.2. We find that the low-mass end slope of the GSMF, after correcting from surface brightness incompleteness, is α≈−1.4\alpha\approx-1.4, consistent with previous determinations. The obtained HI MFs agree with radio blind surveys. Similarly, the H2_2 MFs are consistent with CO follow-up optically-selected samples. We estimate the impact of systematics due to mass-to-light ratios and find that our MFs are robust against systematic errors. We deconvolve our MFs from random errors to obtain the intrinsic MFs. Using the MFs, we calculate cosmic density parameters of all the baryonic components. Baryons locked inside galaxies represent 5.4% of the universal baryon content, while ∼96\sim96% of the HI and H2_2 mass inside galaxies reside in late-type morphologies. Our results imply cosmic depletion times of H2_2 and total neutral H in late-type galaxies of ∼1.3\sim 1.3 and 7.2 Gyr, respectively, which shows that late type galaxies are on average inefficient in converting H2_2 into stars and in transforming HI gas into H2_2. Our results provide a fully self-consistent empirical description of galaxy demographics in terms of the bivariate gas--stellar mass distribution and their projections, the MFs. This description is ideal to compare and/or to constrain galaxy formation models.Comment: 37 pages, 17 figures. Accepted for publication in PASA. A code that displays tables and figures with all the relevant statistical distributions and correlations discussed in this paper is available here https://github.com/arcalette/Python-code-to-generate-Rodriguez-Puebla-2020-result

    On the heating of source of the Orion KL hot core

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    We present images of the J=10-9 rotational lines of HC3N in the vibrationally excited levels 1v7, 1v6 and 1v5 of the hot core (HC) in Orion KL. The images show that the spatial distribution and the size emission from the 1v7 and 1v5 levels are different. While the J=10-9 1v7 line has a size of 4''x 6'' and peaks 1.1'' NE of the 3 mm continuum peak, the J=10--9 1v5 line emission is unresolved (<3'') and peaks 1.3'' south of the 3 mm peak. This is a clear indication that the HC is composed of condensations with very different temperatures (170 K for the 1v7 peak and >230>230 K for the 1v5 peak). The temperature derived from the 1v7 and 1v5 lines increases with the projected distance to the suspected main heating source I. Projection effects along the line of sight could explain the temperature gradient as produced by source I. However, the large luminosity required for source I, >5 10^5 Lsolar, to explain the 1v5 line suggests that external heating by this source may not dominate the heating of the HC. Simple model calculations of the vibrationally excited emission indicate that the HC can be internally heated by a source with a luminosity of 10^5 Lsolar, located 1.2'' SW of the 1v5 line peak (1.8'' south of source I). We also report the first detection of high-velocity gas from vibrationally excited HC3N emission. Based on excitation arguments we conclude that the main heating source is also driving the molecular outflow. We speculate that all the data presented in this letter and the IR images are consistent with a young massive protostar embedded in an edge-on disk.Comment: 13 pages, 3 figures, To be published in Ap.J. Letter

    REDE SOCIAL INFORMAL E TRANSFERÊNCIA DE CONHECIMENTO TÉCNICO EM P&D

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    No mundo corporativo há um crescente interesse em Gestão de Conhecimento (CG). A capacidade das empresas de compilar o conhecimento acumulado, organizá-lo e torná-lo uma vantagem competitiva, é hoje o grande desafio das empresas modernas. Cada vez mais, as organizações são valoradas por aquilo que sabem. Conhecer a organização, sua cultura e como seus funcionários se relacionam formal ou informalmente, torna-se fundamental para a elaboração de estratégias para implantação de uma GC eficiente. O relacionamento formal é facilmente identificado nos organogramas de qualquer tipo de organização já os relacionamentos informais, que geram grande sinergia, são pouco explorados como forma de compartilhamento de conhecimento.O presente artigo tem como objetivo apresentar como ocorre o relacionamento interpessoal numa gerência geral do CENPES (Centro de Pesquisas Leopoldo Américo Miguez de Mello) que desenvolve projetos de engenharia básica para a indústria do petróleo e gás, identificando seus principais atores através da técnica da Análise das Redes Sociais (ARS). Buscou-se revelar como a amostra de funcionários está organizada, levando-se em consideração quatro fatores de análise, a saber: informação, conhecimento, amizade e confiança. Para obtenção dos dados foi realizada uma pesquisa através de questionários aplicados aos funcionários da unidade estudada. Para as análises foram utilizadas as ferramentas UCINET e NETDRAW. Como resultados foram identificados os principais atores dos quatro fatores de análise e qual o relacionamento entre o grupo. Verificou-se gargalo na transferência de informação e conhecimento bem como pouca interação entre as gerências estudadas

    Visible light assisted organosilane assembly on mesoporous silicon films and particles

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    Porous silicon (PSi) is a versatile matrix with tailorable surface reactivity, which allows the processing of a range of multifunctional films and particles. The biomedical applications of PSi often require a surface capping with organic functionalities. This work shows that visible light can be used to catalyze the assembly of organosilanes on the PSi, as demonstrated with two organosilanes: aminopropyl-triethoxy-silane and perfluorodecyl-triethoxy-silane. We studied the process related to PSi films (PSiFs), which were characterized by X-ray photoelectron spectroscopy (XPS), time of flight secondary ion mass spectroscopy (ToF-SIMS) and field emission scanning electron microscopy (FESEM) before and after a plasma patterning process. The analyses confirmed the surface oxidation and the anchorage of the organosilane backbone. We further highlighted the surface analytical potential of 13 C, 19 F and 29 Si solid-state NMR (SS-NMR) as compared to Fourier transformed infrared spectroscopy (FTIR) in the characterization of functionalized PSi particles (PSiPs). The reduced invasiveness of the organosilanization regarding the PSiPs morphology was confirmed using transmission electron microscopy (TEM) and FESEM. Relevantly, the results obtained on PSiPs complemented those obtained on PSiFs. SS-NMR suggests a number of siloxane bonds between the organosilane and the PSiPs, which does not reach levels of maximum heterogeneous condensation, while ToF-SIMS suggested a certain degree of organosilane polymerization. Additionally, differences among the carbons in the organic (non-hydrolyzable) functionalizing groups are identified, especially in the case of the perfluorodecyl group. The spectroscopic characterization was used to propose a mechanism for the visible light activation of the organosilane assembly, which is based on the initial photoactivated oxidation of the PSi matrixWe acknowledge MSC funding provided by the European Commission through FP7 grant THINFACE (ITN GA 607232) and by Ministerio de Economía y Competitividad through grant NANOPROST (RTC-2016-4776-1

    Food Safety Management in a Global Environment: The Role of Risk Assessment Models

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    Quantitative risk assessment models are playing a minor role in the development of the new EU legal framework for food safety. There is a tendency of the EU institutions to apply the precautionary principle versus the predisposition of the USA institutions to rely on risk analysis. This paper provides a comparison of the role played by quantitative risk assessment models in the development of new policies on food safety in the EU and in the USA, focusing on a study case: the supply chain of shell eggs. We suggest that EU regulatory bodies should reconsider the role that quantitative risk assessment models have to play in order to design more effective food safety management systems.Food safety policy, food safety assurance, risk analysis, risk assessment, precautionary principle, Food Consumption/Nutrition/Food Safety,
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