1,720,962 research outputs found
High performance adaptive optics system with fine tip/tilt control
No full textAdaptive optics is a technique that uses the measurements of a wave front sensor to flatten distorted wave fronts with a deformable mirror in a feedback loop in order to provide diffraction-limited performance with ground-based telescopes. In order to achieve the highest possible Strehl, a measure of performance, the measurement and the control of the most important disturbances (tip and tilt) have to be optimized. These modes, in spite of being the first modes to be controlled, have the biggest impact on the final performance of the system. This paper concentrates on the estimation and control of the atmospheric tip/tilt leaving out for the moment other sources of error that originate inside the telescope in form of vibrations. It will be shown that the proposed control strategy can reduce the residual variance of the controlled modes by a factor 2 and that, if applied to all modes, can achieve a significantly better Strehl
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
The pollicization of the index finger in the aplasia of the thumb
No full textWe have examined 11 patients with aplasia of the thumb and we have treated by pollicization of the index finger. We have conducted a follow up of 5 years. The total absence of the thumb may be an isolated anomaly, but it is often associated with some other congenital malformation. The absent thumb is as an autosomal dominant pathology or may be sporadic. It is frequently observed in the Holt-Oram syndrome, Fanconi's anemia, and ring D chromosome abnormalities. It is occasionally observed in the Rothmund syndrome, trisomy, thalidomide embryopathology and other congenital syndromes. An absent radius is almost always associated with an absent thumb, except in thrombocytopenia radial aplasia (Fanconi's syndrome), where the thumb is present even when the radius is absent. The treatment in most cases of the absent thumb is to perform a pollicization of the index finger. Our isolated congenital absence of the thumb patients have been treated with pollicization as described by Buck-Gramcko works well. It is a beautiful operation for the congenitally deformed, aplastic, or missing thumb. Pollicization of the index finger gives good functional and cosmetic results which are maintained. Conclusions: The total absence of the thumb in the congenitally pathology gives the hand of the patient insufficient in the functional movement and no cosmetic. So the pollicization with the second index fined gives a good reconstruction for the neo-thumb. In our five years follow-up, the 11 young patients that were treated with the pollicization, they are satisfy and use the neo-thumb like normal thumb. In congenitally absent thumbs clearly support the fact that the pollicized digit is used by most patients and is not ignored or bypassed
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
- …
