4,459 research outputs found

    The structure and kinematics of the the Galaxy thin gaseous disc outside the solar orbit

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    The rotation curve of the Galaxy is generally thought to be flat. However, using radial velocities from interstellar molecular clouds, which is common in rotation curve determination, seems to be incorrect and may lead to incorrectly inferring that the rotation curve is flat indeed. Tests basing on photometric and spectral observations of bright stars may be misleading. The rotation tracers (OB stars) are affected by motions around local gravity centers and pulsation effects seen in such early type objects. To get rid of the latter a lot of observing work must be involved. We introduce a method of studying the kinematics of the thin disc of our Galaxy outside the solar orbit in a way that avoids these problems. We propose a test based on observations of interstellar CaII H and K lines that determines both radial velocities and distances. We implemented the test using stellar spectra of thin disc stars at galactic longitudes of 135{\degr} and 180{\degr}. Using this method, we constructed the rotation curve of the thin disc of the Galaxy. The test leads to the obvious conclusion that the rotation curve of the thin gaseous galactic disk, represented by the CaII lines, is Keplerian outside the solar orbit rather than flat.Comment: 33 pages, 18 figures, accepted for publication in Publications of the Astronomical Society of the Pacific, 2015. February

    Macroscopic Anisotropy and Symmetry Breaking in the Pyrochlore Antiferromagnet Gd2_{2}Ti2_{2}O7_{7}}

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    In the Heisenberg antiferromagnet Gd2Ti2O7Gd_2Ti_2O_7, the exchange interactions are geometrically frustrated by the pyrochlore lattice structure. This ESR study reveals a strong temperature dependent anisotropy with respect to a [111] body diagonal below a temperature TA=80T_A=80 K, despite the spin only nature of the Gd3+Gd^{3+} ion. Anisotropy and symmetry breaking can nevertheless appear through the superexchange interaction. The presence of short range planar correlation restricted to specific Kagom\'{e} planes is sufficient to explain the two ESR modes studied in this work.Comment: 4 pages, 5 figure

    Economic Analysis of Cellulase Production by Clostridium thermocellum in Solid State and Submerged Fermentation

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    Replaced with revised version of paper 09/24/04.Resource /Energy Economics and Policy,

    How to Make City Traffic Adaptive on an Algorithm for the Adaptive Automatic Control of the Main Vehicular Traffic Streams in an Urban Area

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    The aim of this paper is to point out that the same basic ideas that have appeared useful for data network systems could also be useful in solving street traffic control problems

    The PASTEL catalogue of stellar parameters

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    The PASTEL catalogue is an update of the [Fe/H] catalogue, published in 1997 and 2001. It is a bibliographical compilation of stellar atmospheric parameters providing (Teff,logg,[Fe/H]) determinations obtained from the analysis of high resolution, high signal-to-noise spectra, carried out with model atmospheres. PASTEL also provides determinations of the one parameter Teff based on various methods. It is aimed in the future to provide also homogenized atmospheric parameters and elemental abundances, radial and rotational velocities. A web interface has been created to query the catalogue on elaborated criteria. PASTEL is also distributed through the CDS database and VizieR. To make it as complete as possible, the main journals have been surveyed, as well as the CDS database, to find relevant publications. The catalogue is regularly updated with new determinations found in the literature. As of Febuary 2010, PASTEL includes 30151 determinations of either Teff or (Teff,logg,[Fe/H]) for 16649 different stars corresponding to 865 bibliographical references. Nearly 6000 stars have a determination of the three parameters (Teff,logg,[Fe/H]) with a high quality spectroscopic metallicity.Comment: 5 pages, accepted for publication in A&A. The PASTEL catalogue can be queried at http://pastel.obs.u-bordeaux1.fr/ or http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=B/paste

    Thinking in action: Need for cognition predicts self-control together with action orientation

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    Need for Cognition describes relatively stable interindividual differences in cognitive motivation. Previous research has shown relations of Need for Cognition to Self-Control–a capacity that can be broadly defined as resistance to temptation–yet, the processes underlying this relation remain unclear. One explanation for the prediction of Self-Control by Need for Cognition can be an increased motivation to invest cognitive effort with higher levels of Need for Cognition. Another possible link could be that individual differences in the implementation of Self-Control intentions may play a moderating or mediating role for the predictive value of Need for Cognition. Such individual differences in the self-motivated initiation and maintenance of intentions are described by dispositional Action Orientation. Therefore, in the present study, Action Orientation was examined with regard to its possible role in explaining the relation of Need for Cognition to Self-Control. In a sample of 1209 young adults, Self-Control was assessed with two different self-report instruments and moderation and mediation models of the relationship between Need for Cognition, Action Orientation, and Self-Control were tested. While there was no evidence for a moderating role of Action Orientation in explaining the relation of Need for Cognition and Self-Control, Action Orientation was found to partly mediate this relation with a remaining direct effect of Need for Cognition on Self-Control. These results add to the conceptual understanding of Need for Cognition and demonstrate the relevance of trait variables to predict Self-Control
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