1,721,013 research outputs found
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
Recombinant Expression of a Tick Saliva Serine Protease Inhibitor
No full textThe Ixodes scapularis tick is a medically important vector of five out of the 15 reportable human tick borne disease agents, making it a great concern to public health. In order to develop vaccines against tick borne disease agents, it is imperative to understand the mechanisms of tick feeding. During feeding, ticks inject saliva containing several proteins into host, including serpins (serine protease inhibitors). Serpins are the largest superfamily of protease inhibitors and are believed to aid the successful transmission of disease agents into a host by allowing ticks to evade host defenses during feeding. Tick serpins inhibit host proteolytic defense pathways like coagulation, inflammation, hemostasis, and much more. In this study, yeast recombinant protein expression constructs of Serpin 1B, was prepared using Pichia pastoris expression system. Large-scale expression of Serpin 1B, purification, and substrate hydrolysis experiments were subsequently performed. This project successfully cloned and expressed Serpin1B using Pichia pastoris expression system. In this study, biochemical characterization showed that rSerpin1B inhibits chymotrypsin by at least 33% and trypsin by 99%
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
Characterization of an Ixodes Scapularis Serine Proteinase Inhibitor
Get PDFThe blacklegged tick, Ixodes scapularis is a medically important tick species that transmits six of the fifteen human tick-borne disease agents in the United States. Without successful feeding, ticks cannot cause damage to the host nor transmit any disease agents. Thus, a deeper understanding of how ticks accomplish feeding could lead to the identification of proteins to target for development of innovative tick control methods. Members of the serpin superfamily (serine protease inhibitors) are among proteins thought to facilitate tick feeding. In order to complete feeding, ticks have to overcome serine protease mediated pathways that are controlled by serpins. This honors thesis describes the characterization process of I. scapularis tick Serpin 1A. In addition to providing qualitative and semi-quantitative RT-PCR analysis of Serpin 1A in the nymph and female adult development stages at different feeding intervals (unfed, 24h, 48h, 72h, 96h, and 120h). The Serpin 1A mature open reading frame (ORF1A) was successfully subcloned into the yeast recombinant protein expression plasmid, pPICZ��C, which was effectively used to transfect Pichia pastoris strain X-33, yeast cells. Efforts to induce recombinant Serpin 1A protein failed, therefore halting the biochemical characterization of this protein. Further research into the expression of recombinant Serpin 1A is needed for follow-up experiments to characterize the role(s) of Serpin 1A in tick feeding. Even though, characterization of the protein was halted, the qualitative and semi-quantitative data revealed that Serpin 1A mRNA was expressed at different feeding intervals and highly expressed during the first day and second day of feeding in the salivary gland. These findings suggest that Serpin 1A is associated with the I. scapularis tick feeding physiology. Moreover, it implies that this serpin is mostly associated with the early stages of tick feeding in nymph and female adult tick organs. Furthermore, these results propose that Serpin 1A may play a role in pathogen development, since the salivary gland is considered to be the site for pathogen development in tick anatomy. Most tick borne pathogens spread by this species are transmitted after the tick has for more than one day by the early life states and female adult stage. Thus, this information on Serpin 1A could be utilized to target this serpin in an anti-tick vaccine that is aimed at preventing tick borne disease transmission
Functional Analysis of a Cross-tick Species Conserved Amblyomma americanum Serine Protease Inhibitor 39
Get PDFHard ticks such as Amblyomma americanum are pool feeders that accomplish feeders by lacerating host tissue and then sucking host blood that bleeds into the wounded area. Host defense mechanisms to tick feeding activity are serine protease mediated pathways, blood clotting and inflammation that are controlled by serpins. It���s hypothesized that ticks utilize serpins to evade host defense mechanisms to successfully feed and transmit disease agents. As part of a long-term goal to understand role(s) of A. americanum serpins in tick feeding regulation, the goal of this research was to produce a recombinant (r) of a highly cross-tick species conserved A. americanum serpin, AAS39 in yeast and insect cells. The mature protein open reading frame was amplified and successfully cloned into the yeast expression plasmid, but the not insect cell plasmid. The yeast plasmid was used to transform Pichia pastoris yeast cells and rAAS39 was successfully expressed and affinity purified. Results from this research sets up the stage for follow up experiments to characterize the role(s) of rAAS39 in tick feeding regulation
Designing and Expressing a Recombinant Tick Saliva Chimera
Get PDFWhen ticks feed, they inject numerous proteins into the host that modulate the host���s defense mechanism to tick feeding activity. When animals are repeatedly infested with ticks, they develop an immune response to tick saliva proteins. On these animals ticks have difficulties to complete feeding, acquire, and transmit disease agents, and reproduce. Thus immunization of animals with recombinant tick saliva proteins has been proposed. The strategy of this research is to deliver chimeric tick saliva protein antigens. Three cross-tick species conserved genes that encode for Lone Star tick, Amblyomma americanum tick saliva proteins were identified. cDNA regions that code for putative immunogenic regions were spliced together to make a chimeric tick saliva protein. The recombinant tick saliva protein chimera will be expressed and used to immunize rabbits against tick feeding
Expression and Functional Characterization of Amblyomma americanum tick saliva protein, BP6contig8.
Get PDFIn an attempt to feed on their hosts, ticks secrete saliva proteins to disrupt host defense mechanisms to tick feeding such as blood coagulation and inflammation. To discover tick proteins that are injected into the vertebrate host during tick feeding, a 24h Amblyomma americanum phage display expression library was immuno-screened using antibodies to 24h A. americanum tick saliva proteins. While there are some tick saliva proteins that have known functions, there are many that have yet to be characterized. The goal of this undergraduate thesis research is to gain insight into the function(s) of BP6contig8 (BP6C8) in tick feeding physiology. Data in this research suggest that BP6C8 is likely associated tick feeding events during the first five days of tick feeding as revealed by qualitative RT-PCR analysis of 24-120h fed tick cDNA. The major goal of this thesis research has been achieved: recombinant (r) BP6C8 was expressed in insect cells. The remaining experiments will be to optimize large scale production of rBP6C8 and gauging insight into role(s) of this protein in tick feeding physiology
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
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