15 research outputs found

    Coude-feed stellar spectral library - atmospheric parameters

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    Context: Empirical libraries of stellar spectra play an important role in different fields. For example, they are used as reference for the automatic determination of atmospheric parameters, or for building synthetic stellar populations to study galaxies. The CFLIB (Coude-feed library, Indo-US) database is at present one of the most complete libraries, in terms of its coverage of the atmospheric parameters space (Teff, log g and [Fe/H]) and wavelength coverage 3460 - 9464 A at a resolution of 1 A FWHM. Although the atmospheric parameters of most of the stars were determined from detailed analyses of high-resolution spectra, for nearly 300 of the 1273 stars of the library at least one of the three parameters is missing. For the others, the measurements, compiled from the literature, are inhomogeneous. Aims: In this paper, we re-determine the atmospheric parameters, directly using the CFLIB spectra, and compare them to the previous studies. Methods: We use the ULySS program to derive the atmospheric parameters, using the ELODIE library as a reference. Results: Based on comparisons with several previous studies we conclude that our determinations are unbiased. For the 958 F,G, and K type stars the precision on Teff, log g, and [Fe/H] is respectively 43 K, 0.13 dex and 0.05 dex. For the 53 M stars they are 82 K, 0.22 dex and 0.28 dex. And, for the 260 OBA type stars the relative precision on Teff is 5.1%, and on log g, and [Fe/H] the precision is respectively 0.19 dex and 0.16 dex. These parameters will be used to re-calibrate the CFLIB fluxes and to produce synthetic spectra of stellar populations.Comment: 51 pages, accepted for publication in Astronomy and Astrophysic

    Barium and iron abundances in red giants

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    The role of complexity for digital twins of cities

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    We argue that theories and methods drawn from complexity science are urgently needed to guide the development and use of digital twins for cities. The theoretical framework from complexity science takes into account both the short-term and the long-term dynamics of cities and their interactions. This is the foundation for a new approach that treats cities not as large machines or logistic systems but as mutually interwoven self-organizing phenomena, which evolve, to an extent, like living systems

    Proceedings of the 26th Annual Philippine Biodiversity Symposium

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    The Philippine Biodiversity Symposium is an annual gathering of researchers and practitioners working in the fields of wildlife studies and biodiversity conservation in the Philippines. The 26th Annual Philippine Biodiversity Symposium was held on July 18-22, 2017 at the Ateneo de Manila University. Under the topic “New and Emerging Trends in Biodiversity Research and Conservation”, 16 plenary and 46 session presentations along with numerous posters from more than 300 participants focused on current research results and conservation efforts on Philippine biodiversity. The symposium was co-organized by the Biodiversity Conservation Society of the Philippines (BCSP) and the Ateneo de Manila University Department of Biology, and presented in cooperation with Biodiversity Management Bureau of DENR, Foundation for the Philippine Environment, GIZ, Team Energy Foundation and Pensoft Publishers. The event was sponsored by Pensoft, the Center for Conservation Innovation, Crocodylus porosus Philippines Inc., Energy Development Cooperation, roots.asia, Center for Outdoor Recreation and Expedition, Quezon City Government and Ateneo de Manila University Press, among others. The event draws over 250 participants from the academic and research institutions, government agencies, non-government organizations, independent researchers, and high school, undergraduate and graduate students. Selected studies that have been presented during the symposium are published in here

    MAO Inhibitory Activity of 2-Arylbenzofurans versus 3-Arylcoumarins: Synthesis, invitro Study, and Docking Calculations

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    Monoamine oxidase (MAO) is an important drug target for the treatment of neurological disorders. Several 3-arylcoumarin derivatives were previously described as interesting selective MAO-B inhibitors. Preserving the trans-stilbene structure, a series of 2-arylbenzofuran and corresponding 3-arylcoumarin derivatives were synthesized and evaluated as inhibitors of both MAO isoforms, MAO-A and MAO-B. In general, both types of derivatives were found to be selective MAO-B inhibitors, with IC50 values in the nano- to micromolar range. 5-Nitro-2-(4- methoxyphenyl)benzofuran (8) is the most active compound of the benzofuran series, presenting MAO-B selectivity and reversible inhibition (IC50=140 nm). 3-(4’-Methoxyphenyl)-6-nitrocoumarin (15), with the same substitution pattern as that of compound 8, was found to be the most active MAO-B inhibitor of the coumarin series (IC50=3 nm). However, 3-phenylcoumarin 14 showed activity in the same range (IC50=6 nm), is reversible, and also severalfold more selective than compound 15. Docking experiments for the most active compounds into the MAO-B and MAO-A binding pockets highlighted different interactions between the derivative classes (2-arylbenzofurans and 3-arylcoumarins), and provided new information about the enzyme–inhibitor interaction and the potential therapeutic application of these scaffolds
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