1,720,983 research outputs found
Model validation of the polar clouds at Saturn as inferred by Cassini/VIMS data in the visual range
No full textABSTRACT In this preliminary study the goal of the work is to extend the analysis of a set of clouds observed in the South Polar atmosphere of Saturn by VIMS on Cassini, from the infrared range (previously done) to the visual range. As a starting point we considered the best fit values (least square method) of the parameters for the same set of clouds, calculated through a line-by-line radiative transfer model applied to the spectral information from the infrared channel of VIMS in the range 1-5 μm. Those same parameters like composition, particle concentrations and sizes have been used with a different radiative transfer code suitable for working in the range of wavelengths 0.3-1.0 μm (LibRadtran).
As our first simulations do not well agree with the observed spectra, an improvement is suggested to reduce the relative difference between the model and the measurement. Possible sources of the observed discrepancies and the procedure to reduce them, are discussed
Cloud-tops and vertical structure of Saturn’s 2011-2012 giant vortex by means of Cassini/VIMS-V data analysis
No full textIn this work, selected regions of the giant vortex observed at Saturn’s North hemisphere since January 2011 have been investigated using observations from VIMS-V, the visual channel of the Visual and Infrared Mapping Spectrometer on board the Cassini spacecraft. Its wavelength range is 0.4-1.0 μm. By studying the 2D images acquired by VIMS-V, especially comparing those relative to the transmission windows wavelengths to those relative to the strongest CH4 absorption bands in this range, we can postulate how the vortex can be vertically structured. A forward radiative transfer model has been developed based on the LibRadtran code, and adapted to Saturn’s atmosphere. Then an inverse code, that takes advantage of the optimal estimation technique, has been implemented to retrieve the microphysical and geometrical properties of the clouds. Best fits of the radiance spectra relative to the different selected regions are produced by means of a least square analysis and then the cloud top pressures are estimated along with other microphysical properties. Different vertical structures have been tested to define the most probable one. This work is the first step in the direction of monitoring the characteristics of the vortex’s clouds versus time
Spectral ultraviolet measurements by a multichannel monitor and a Brewer spectroradiometer: A field study
No full textTwo different instruments for measuring, the spectral UV irradiance were used in a field comparison study in July 2000 in Rome, Italy: a Brewer spectrophotometer and a moderate-bandwidth idler radiometer (GUV-511C). The Brewer is designed to measure file solar spectral irradiances in the region from 290 nm to 325 nm with a spectral resolution of 0.5 nm. The GUV-511C measures band-averaged spectral irradiance at four wavelengths: 305. 320. 340 and 380 nm with a bandwidth depending oil the filter type for each channel (about 10 nm full width half maximum, FWHM). Comparisons between the two instruments Were made for 5 days for the two wavelengths 305 and 320 nm under different meteorological conditions with the Brewer taken as the reference
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
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
- …
