1,721,088 research outputs found
SiO J = 5-4 in the HH 211 Protostellar Jet Imaged with the Submillimeter Array
No full text[[abstract]]We have mapped the SiO J = 5-4 line at 217 GHz from the HH 211 molecular outflow with the Submillimeter Array (SMA). The high-resolution map (1.6" × 0.9") shows that the SiO J = 5-4 emission comes from the central narrow jet along the outflow axis with a width of ~0.8" (~250 AU) FWHM. The SiO jet consists of a chain of knots separated by 3"-4" (~1000 AU), and most of the SiO knots have counterparts in shocked H2 emission seen in a new, deep VLT near-infrared image of the outflow. A new, innermost pair of knots have been discovered at just +/-2" from the central star. The line ratio between the SiO J = 5-4 data and the upper limits from the SiO J = 1-0 data of Chandler & Richer suggests that these knots have a temperature in excess of 300-500 K and a density of (0.5-1) × 107 cm-3. The radial velocity measured for these knots is ~30 km s-1, comparable to the maximum velocity seen in the entire jet. The high temperature, high density, and velocity structure observed in this pair of SiO knots suggest that they are closely related to the primary jet launched close to the protostar.[[fileno]]2010504010041[[department]]天文
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
POLARIZATION OF THE EMISSION IN ORION IRc2
No full text M.C.H. Wright, R.L. Plamheck, L.G. Mundy and L.W. Looney Astrophys. J. 455, L185 (1995).Author Institution: Department of Astronomy, University of Illinois; Radio Astronomy Laboratory, University of CaliforniaWe mapped the polarization structure of emission in Orion IRc2 in both the ground state and the vibrationally excited state . The data were obtained using the Berkeley-Illinois-Maryland-Association (BIMA) array at a frequency of 86 GHz. The angular resolution that was achieved was 0.4''. Both the ground state and the vibrationally exited state are associated with maser emission from a disk around a young stellar object (YSO) in . The emission has 3\% linear polarization which rotates across the spectral line. The fractional linear polarization and the position angle of the plane of polarization vary with time. The v=0 polarized emission seems to arise from a highly compact source but the data show that the polarization angle is constant across the spectrum. In addition, there is no time variability. The data are consistent with a rotating, expanding disk between 40 and 80 AU from a young stellar object (YSO) associated with a radio source (I). The magnetic field is entrained in the disk's motion. At larger radii from source I, the traces a flared disk structure on a scale of 1000 AU. The magnetic field on these scales is not strongly influenced by the star formation, or the outflow which is centered on source I. This work was partially funded by NSF grants AST 96-13998, AST96-13999 and by the University of Illinois and the University of California
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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A SiO J = 5 → 4 Survey Toward Massive Star Formation Regions
No full textWe performed a survey in the SiO J = 5 → 4 line toward a sample of 199 Galactic massive star-forming regions at different evolutionary stages with the Submillimeter Telescope (SMT) 10 m and Caltech Submillimeter Observatory (CSO) 10.4 m telescopes. The sample consists of 44 infrared dark clouds (IRDCs), 86 protostellar candidates, and 69 young H ii regions. We detected SiO J = 5 → 4 line emission in 102 sources, with a detection rate of 57%, 37%, and 65% for IRDCs, protostellar candidates, and young H ii regions, respectively. We find both broad line emissions with full widths at zero power >20 km s−1 and narrow line emissions of SiO in objects at various evolutionary stages, likely associated with high-velocity shocks and low-velocity shocks, respectively. The SiO luminosities do not show apparent differences among various evolutionary stages in our sample. We find no correlation between the SiO abundance and the luminosity-to-mass ratio, indicating that the SiO abundance does not vary significantly in regions at different evolutionary stages of star formation.National Key R&D Program of China [2017YFA0402704]; Natural Science Foundation of China [11590783]; CfA predoctoral fellowship; Chinese Scholarship Council; National Natural Science Foundation of China [11629302, U1731237]This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
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