1,721,014 research outputs found
X-ray structure of the cyclomaltohexaicosaose triiodide inclusion complex provides a model for amylose-iodine at atomic resolution
No full textCyclomaltohexaicosaose (CA26) is folded into two 1 2/3 turns long V-helices that are oriented antiparallel. Crystals of complexes of CA26 with NH 4I 3 and Ba(I 3) 2 are brown and X-ray analyses show that I 3 - units are located in the ∼5 A wide central channels of the V-helices. In the complex with NH 4I 3, two CA26 molecules are stacked to form 2×1 2/3 turns long channels harbouring 3 I 3 - at 3.66-3.85 A inter I 3 - distance (shorter than van der Waals distance, 4.3 A), whereas in the Ba(I 3) 2 complex, CA26 are not stacked and only one I 3 - each fills the V-helices. Glucose I contacts are formed with C5-H, C3-H, C6-H and (at the ends of the V-helices) with O6 in (+) gauche orientation. By contrast, O2, O3, O4 and O6 in the preferred (-) gauche orientation do not interact with I because these distances are ≥4.01 A and exceed the van der Waals I⋯O sum of radii by about 0.5 A except for one O2⋯I distance of 3.68 A near the end of one V-helix. Raman spectra indicate that the complexes share the presence of I 3 - with blue amylose-iodine
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
The C-terminal subdomain (IF2 C-2) contains the entire fMet-tRNA binding site of initiation factor IF2.
No full textPrevious protein unfolding studies had suggested that
IF2 C, the 24.5-kDa fMet-tRNA binding domain of Bacillus
stearothermophilus translation initiation factor IF2,
may consist of two subdomains. In the present work, the
four Phe residues of IF2 C (positions 531, 599, 657, and
721) were replaced with Trp, yielding four variant proteins
having intrinsic fluorescence markers in different
positions of the molecule. Comparison of the circular
dichroism and Trp fluorescence changes induced by increasing
concentrations of guanidine hydrochloride
demonstrated that IF2 C indeed consists of two subdomains:
the more stable N-terminal (IF2 C-1) subdomain
containing Trp-599, and the less stable C-terminal (IF2
C-2) subdomain containing Trp-721. Isolated subdomain
IF2 C-2, which consists of just 110 amino acids (from
Glu-632 to Ala-741), was found to bind fMet-tRNA with
the same specificity and affinity as native IF2 or IF2
C-domain. Trimming IF2 C-2 from both N and C termini
demonstrated that the minimal fragment still capable of
fMet-binding consists of 90 amino acids. IF2 C-2 was
further characterized by circular dichroism; by urea-,
guanidine hydrochloride-, and temperature-induced unfolding;
and by differential scanning calorimetry. The results indicate that IF2 C-2 is a globular molecule containing
predominantly b structures (25% antiparallel
and 8% parallel b strands) and turns (19%) whose structural
properties are not grossly affected by the presence
or absence of the N-terminal subdomain IF2 C-1
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
