1,720,965 research outputs found
Double photoionization of N2O molecules in the 28-40 eV energy range
No full textThe double photoionization of N2O molecules, in the 28–40 eV energy range, has been studied by synchrotron radiation. In the whole
energy range, dissociative ionization producing N++NO+ or Nþ
2 þ Oþ has been observed. Below 35.5 eV, these two processes involve
the formation of some autoionizing states. In the range between 35.5 and 38.5 eV the two processes occur instead by a direct coulomb
explosion of the N2O2+ dication. Above 38.5 eV the dissociation leading to NO++N+ is also promoted by the formation of a dication
metastable state which decays by fluorescence to the ground state and then dissociates
Dissociative double photoionization of CO2 molecules in the 36-49 eV energy range: angular and energy distribution of ion products
No full textDissociative double photoionization of CO2, producing CO+ and O+ ions, has been studied in the 36–49 eV energy range using synchrotron radiation and ion–ion coincidence imaging
detection. At low energy, the reaction appears to occur by an indirect mechanism through the formation of CO+ and an autoionizing state of the oxygen atom. In this energy range the reaction leads to an isotropic distribution of products with respect to the polarization vector of the light. When the photon energy increases, the distribution of products becomes anisotropic, with the two ions preferentially emitted along the direction of the light polarization vector. This
implies that the molecule photoionizes when oriented parallel to that direction and also that the CO2 2+ dication just formed dissociates in a time shorter than its typical rotational period. At low photon energy, the CO+ and O+ product ions separate predominantly with a total kinetic energy between 3 and 4 eV. This mechanism becomes gradually less important when the photon energy
increases and, at 49 eV, a process where the two products separate with a kinetic energy between 5 and 6 eV is dominant
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
The double photoionization of HCl: An ion-electron coincidence study
No full textThe double photoionization of HCl molecules by synchrotron radiation has been studied in the
energy range between 30 and 50 eV. The HCl21 and Cl21 product ions have been detected by a
photoelectron–photoion-coincidence technique, while the H11Cl1 formation, which follows the
double ionization of HCl, has been studied by photoelectron–photoion–photoion coincidence. The
photon energy threshold for the production of HCl21 ions has been found to be 35.460.6 eV, while
for the dissociative channel leading to H11Cl1, it has been measured a threshold at 36.460.6 eV
and a change in the slope of the cross-section energy dependence at 38.760.7 eV. The production
of H1Cl21 occurs with a threshold photon energy of 42.861.1 eV. These results appear to be in a
good agreement with previous data by different experimental techniques and recent theoretical
calculations performed by our laboratory
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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