4,840 research outputs found

    Abundances of metal-weak thick-disc candidates

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    High resolution spectra of 5 candidate metal-weak thick-disc stars suggested by Beers & Sommer-Larsen (1995) are analyzed to determine their chemical abundances. The low abundance of all the objects has been confirmed with metallicity reaching [Fe/H]=-2.9. However, for three objects, the astrometric data from the Hipparcos catalogue suggests they are true halo members. The remaining two, for which proper-motion data are not available, may have disc-like kinematics. It is therefore clear that it is useful to address properties of putative metal-weak thick-disc stars only if they possess full kinematic data. For CS 22894-19 the abundance pattern similar to those of typical halo stars is found, suggesting that chemical composition is not a useful discriminant between thick-disc and halo stars. CS 29529-12 is found to be C enhanced with [C/Fe]=+1.0; other chemical peculiarities involve the s process elements: [Sr/Fe]=-0.65 and [Ba/Fe]=+0.62, leading to a high [Ba/Sr] considerably larger than what is found in more metal-rich carbon-rich stars, but similar to LP 706-7 and LP 625-44 discussed by Norris et al (1997a). Hipparcos data have been used to calculate the space velocities of 25 candidate metal-weak thick-disc stars, thus allowing us to identify 3 bona fide members, which support the existence of a metal-poor tail of the thick-disc, at variance with a claim to the contrary by Ryan & Lambert (1995).Comment: to be published in MNRA

    The Century Survey Galactic Halo Project III: A Complete 4300 deg^2 Survey of Blue Horizontal Branch Stars in the Metal-Weak Thick Disk and Inner Halo

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    We present a complete spectroscopic survey of 2414 2MASS-selected blue horizontal branch (BHB) candidates selected over 4300 deg^2 of the sky. We identify 655 BHB stars in this non-kinematically selected sample. We calculate the luminosity function of field BHB stars and find evidence for very few hot BHB stars in the field. The BHB stars located at a distance from the Galactic plane |Z|<4 kpc trace what is clearly a metal-weak thick disk population, with a mean metallicity of [Fe/H]= -1.7, a rotation velocity gradient of dv_{rot}/d|Z|= -28+-3.4 km/s in the region |Z|<6 kpc, and a density scale height of h_Z= 1.26+-0.1 kpc. The BHB stars located at 5<|Z|<9 kpc are a predominantly inner-halo population, with a mean metallicity of [Fe/H]= -2.0 and a mean Galactic rotation of -4+-31 km/s. We infer the density of halo and thick disk BHB stars is 104+-37 kpc^-3 near the Sun, and the relative normalization of halo to thick-disk BHB stars is 4+-1% near the Sun.Comment: 12 pages in emulateapj format, accepted for publication in February A

    Minimum variance estimates of signal derivatives - A problem in instrument landing systems

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    Minimum variance estimates of signal derivatives with application to case of aircraft descent rate in instrument landing system

    Flash Spectroscopy: Emission Lines from the Ionized Circumstellar Material Around &lt;10-Day-Old Type II Supernovae

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    The American Astronomical Society. All rights reserved.Supernovae (SNe) embedded in dense circumstellar material (CSM) may show prominent emission lines in their early-time spectra (≤10 days after the explosion), owing to recombination of the CSM ionized by the shock-breakout flash. From such spectra ("flash spectroscopy"), we can measure various physical properties of the CSM, as well as the mass-loss rate of the progenitor during the year prior to its explosion. Searching through the Palomar Transient Factory (PTF and iPTF) SN spectroscopy databases from 2009 through 2014, we found 12 SNe II showing flash-ionized (FI) signatures in their first spectra. All are younger than 10 days. These events constitute 14% of all 84 SNe in our sample having a spectrum within 10 days from explosion, and 18% of SNe II observed at ages <5 days, thereby setting lower limits on the fraction of FI events. We classified as "blue/featureless" (BF) those events having a first spectrum that is similar to that of a blackbody, without any emission or absorption signatures. It is possible that some BF events had FI signatures at an earlier phase than observed, or that they lack dense CSM around the progenitor. Within 2 days after explosion, 8 out of 11 SNe in our sample are either BF events or show FI signatures. Interestingly, we found that 19 out of 21 SNe brighter than an absolute magnitude MR = -18.2 belong to the FI or BF groups, and that all FI events peaked above MR = -17.6 mag, significantly brighter than average SNe II

    Impact of Spiritual Well-Being, Spiritual Perspective, and Religiosity on the Self-Rated Health of Jordanian Arab Christians

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    The purpose of this study was to explore associations of spiritual well-being, spiritual perspective, and religiosity with self-rated health in a convenience sample of 340 adult Jordanian Arab Christians. Data were collected through church and community groups. Results indicated that spiritual well-being and religiosity were positively associated with self-rated health, but in the final regression model only spiritual well-being retained a significant association after controlling for the other spiritual and religious measures. In conclusion, spirituality and religiosity are important to Jordanian Arab Christians’ health and well-being, and the implications for nursing practice are explored

    Conceptual Frameworks for Multimodal Social Signal Processing

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    This special issue is about a research area which is developing rapidly. Pentland gave it a name which has become widely used, ‘Social Signal Processing’ (SSP for short), and his phrase provides the title of a European project, SSPnet, which has a brief to consolidate the area. The challenge that Pentland highlighted was understanding the nonlinguistic signals that serve as the basis for “subconscious discussions between humans about relationships, resources, risks, and rewards”. He identified it as an area where computational research had made interesting progress, and could usefully make more

    An Arabic Version of the Spiritual Well-Being Scale

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    This article reports on two studies to develop and validate an Arabic language version of the Spiritual Well-Being Scale (SWBS). The first study was a pilot study at a major government university in Jordan (N = 75, students). The second and main study was conducted in 5 large regional hospitals in Jordan (N = 63, patients). The SWBS was translated from English to Arabic and reviewed by an expert panel for language, cultural, and spiritual consistency. The Arabic version of the SWBS was revised after the results of the pilot study and further reviewed by an expert panel. The resulting data were subjected to descriptive and factor analysis. Results showed that the final version of the SWBS used in the main study had a two-factor structure consistent with previous studies. Descriptive data for a range of demographic variables are presented. Issues of inadequate translation and lack of variation in responses for some items are identified and the results discussed in light of dominant Islamic theological frameworks. © 2012 Taylor and Francis Group, LLC

    Linking Conversation Analysis and Motion Capturing: How to robustly track multiple participants?

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    Pitsch K, Brüning B-A, Schnier C, Dierker H, Wachsmuth S. Linking Conversation Analysis and Motion Capturing: How to robustly track multiple participants? In: Kipp M, Martin J-C, Paggio P, Heylen D, eds. Proceedings of the LREC Workshop on Multimodal Corpora: Advances in Capturing, Coding and Analyzing Multimodality (MMC 2010). 2010: 63-69.If we want to model the dynamic and contingent nature of human social interaction (e.g. for the design of human robot interaction), analysis and description of natural interaction is required that combines different methodologies and research tools (qualitative/quantitative; manual/automated). In this paper, we pinpoint the requirements and technical challenges for constituting and managing multimodal corpora that arise when linking Conversation Analysis with novel 3D motion capture technologies: i.e. to robustly track multiple participants over an extended period of time. We present and evaluate a solution to by-pass the limits of the current standard Vicon system (using rigid bodies) and ways of mapping the obtained coordinates to a human skeleton model (inverse kinematics) and to export the data into a format that is supported by standard annotation tools (such as ANVIL)

    Airport mobile internet an innovation

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    This paper studies the adoption of mobile Internet by airports. Using a new theoretical model, the study tests whether early adopters of mobile Internet for airports can be considered real innovators. Seventy-five international airports from four different geographical areas and of three different sizes are analyzed. The paper complements the analysis with an additional innovation adoption, the PC-Website, and two dimensions are analyzed: the time of adoption and the degree of maturation. Our findings show that there are four real innovator airports: London Heathrow, London Stansted, Amsterdam Schiphol and Copenhagen. Airport innovation is found to be related to geographical location and commercial revenue rather than to airport size. The four real innovator airports iPhone apps are used as case studies to identity best practices for the delivery of airport mobile services
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