1,720,968 research outputs found
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
A Structural Study on the Specificity of F1 Protease
Full text linkSpecificity studies of a thermostable alkaline serine protease F1 with its
substrates were carried out through computational docking method.
Structures of a series of synthetic peptide substrates were docked to the active
site of the homology modelled F1 protease using AutoDock 3.0.5. The
resulting clusters of the substrates that were docked were analysed by
inspecting the energetic results and the orientation of each cluster to
determine the arrangement of productive binding. The amino acids of the
binding site that participated in the hydrophobic and hydrogen-bond
interactions were also determined. Docking results showed that all substrates
tested bound near the catalytic residues with SucAAPFpNA, the biggest
substrate, showing the most negative docked energy value @docked = -18.75
kcal/mol). Smaller substrates such as GpNA and AApNA showed higher
docked energy (Edocked = -7.77 kcal/mol and -8.77 kcal/mol, respectively). The
best docked structure of each substrate was determined from the clusters. It
was found that most of the lowest Edocked conformations display the best
docked orientations with respect to the least distance calculated between the
carbonyl carbon of the substrate PI residue and y-oxygen of the Ser226
catalytic triad. From the results, it also demonstrated that S1, S2 and S4
subsites of the enzyme play a critical role in determining the substrate
specificity of F1 protease from the point of view that bigger-sized substrates
such as SucAAPFpNA and SucAAPLpNA showed more favourable Edocked.
This work also support the hypothesis that the catalytic serine and histidine
residues were essential in catalysis as well as in stabilizing the enzymesubstrate
complex for binding.
Validation of computational study was carried out through biochemical
assay. It was found that SucAAPFpNA was the most preferred substrate for
the enzyme with specific activity of 3.079 U/mg followed by SucAAPLpNA
at 1.016 U/mg. SucAAPFpNA was also observed to show the highest binding
affinity towards the protease (Km = 1.26mM) and the highest catalytic ratio
(1.226 min-l.rnM-1) compared to the other substrates tested. Similar to
computational observations, smaller peptides showed lower specific activity
and binding affinity towards the protease. Rank-order of the substrates tested
for the docking and experimental methods were found to be similar for the
top two substrates, with lesser agreement for the other substrates
Nuclear magnetic resonance spectroscopic studies of the structure and interactions between hepatitis B virus core and surface antigens with peptides
Full text linkHepatitis B virus (HBV) infection remains a health problem globally despite the availability of effective vaccines. There are several approaches in designing an antiviral drug based on the virus life cycle. This study focuses on two antiviral approaches. The first approach is to discover a peptide that can block the virus from entering hepatocyte cells. Previous studies have implicated HBV surface antigen (HBsAg) to be involved in the virus entry into the host cells. Thus, a specific ligand targeting the immunodominant region of HBsAg is desired in neutralizing the infectivity of the virus. In a previous study, a disulfide constrained cyclic peptide cyclo S1,S9 Cys-Glu-Thr-Gly-Ala-Lys-Pro-His-Cys (S1, S9-cyclo-CETGAKPHC) was isolated from a phage displayed cyclic peptide library using an affinity selection method against HBsAg. The cyclic peptide binds tightly to the immunodominant region on HBsAg. Consequently, this study was aimed to elucidate the threedimensional structure of the cyclic peptide and its interaction with HBsAg in silico. The solution structure of this cyclic peptide was solved using 1H, 13C,and 15N NMR spectroscopy and molecular dynamics simulations with NMRderived distance and torsion angle restraints. The cyclic peptide adopted two distinct conformations due to the isomerization of the Pro residue with one structured region in the ETGA sequence. Docking studies of the peptide ensemble with a model structure of HBSAg revealed that the cyclic peptide can potentially be developed as a therapeutic drug that inhibits the virus–host interactions. The second approach is to design a peptide based on the viral surface antigen as an inhibitor to block the viral assembly. This strategy involves interaction studies between HBV core antigen (HBcAg) and HBsAg. It is of important to understand the interactions between the two viral proteins because of their involvement in the assembly of the virus. In this study, two peptides of 25 residues long were chosen from different regions of HBsAg. The peptides, designated preS and S were ligated into pGEX-2T vector and expressed in Escherichia coli. The peptides were purified using the GSTrap FF column and the recombinant peptides were chopped off from the GST tag using thrombin. The peptides each at 2.9 kDa were detected by silver staining. However, the yield obtained after cleavage was too little to carry out further studies. As such, these peptides were synthesized chemically using Fmoc chemistry and were analyzed using NMR. The solution structures of both peptides were solved using 1H, 13C, and 15N NMR spectroscopy. Peptide preS has several structured region of β-turns at Ser7- Pro8-Pro9, Arg11-Thr12-Thr13 and Ser22-Thr23-Thr24 sequences whereas peptide S has only one structured region observed at Ser3-Asn4-His5. Both peptides contain bend-like structures surrounding the turn structures. Saturation Transfer Difference (STD) NMR experiments were performed to study the interaction of the preS and S to HBcAg. Several aromatic residues of preS and S were involved in the interaction with HBcAg, indicating their potential as antiviral agents that inhibit the virus morphogenesis. The experiments carried out on the peptides were fundamental methods in designing new antiviral agents for HBV. Promising results were obtained for each peptide, paving the way for future studies on the potential HBV peptide inhibitors
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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