1,720,964 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
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 role of Fas in pathological giardiasis
No full textM.S.Diarrheal disease presents a debilitating burden on many people and economies around the world. Many of these cases are caused by the protozoan parasite Giardia sp., which colonizes the small intestine of a wide range of hosts and disrupts normal digestive and absorptive processes within the gut. Malnutrition caused by giardiasis is largely immune-dependent; the pathology commonly observed within the infected small intestine is likely triggered by activated CD8+ T cells. Understanding the dynamic immune response to Giardia infection is paramount for eventually identifying therapeutic targets and improving preventative measures. We report an influx of FasL+ cells into the duodenum following infection in C57BL/6 mice. Ex vivo restimulation of splenic and mesenteric lymph node (MLN) lymphocytes revealed an IFN- dominant cytokine response, which is conducive for the expansion of activated, FasL expressing CD8+ T cell. This observation prompted us to explore the role of Fas as a potential mediator of Giardia-induced intestinal injury. We observed defective parasite clearance in mice lacking functional Fas (Faslpr). Despite a high parasite burden, Faslpr mice did not exhibit the hallmark signs of a Giardia-injured small intestine, such as reduced disaccharidase activity. Increased ezrin phosphorylation was observed to correlate with reduced disaccharidase in infected C57BL/6 but not Faslpr mice. Faslpr mice exhibited similar levels of enterocyte apoptosis compared to C57BL/6 mice throughout infection. Activated CD8+ T cells within the spleens of infected Faslpr mice were detected, which was likely a consequence of their lympho-proliferative phenotype as this phenomenon was absent in C57BL/6 mice
Host and parasite factors contributing to variation in immunity and pathology in giardiasis.
No full textPh.D.Infection with the flagellated protozoan Giardia duodenalis is a major cause of parasitic diarrheal disease worldwide. G. duodenalis is grouped into 8 assemblages (A through H) but only assemblage A and B parasites infect humans. Infection with G. duodenalis is typically self-limiting although chronic infections do develop in malnourished and immunocompromised hosts. Most cases of giardiasis are asymptomatic, but patients typically present with diarrhea, vomiting, nutrient malabsorption and cramps and these symptoms collectively amount to malnutrition. Giardiasis is estimated to affect 2% of adults and 6% to 8% of children in the developed world nearly 33% of the underdeveloped world. Pediatric cases can lead to growth stunting and this has global health and economic implications for impoverished endemic regions of the world. Attempts to correlate disease severity to a particular assemblage have been contradictory, likely due to variable host and parasite factors. A hallmark of immunopathology in the mouse model of giardiasis is the reduction of intestinal digestive enzymes which is due to CD8+ T cells. We report that the pathological reduction of intestinal sucrase and increased intestinal T cell presence is parasite strain-specific and is associated with assemblage B infection. A comparison of infections in C57BL/6 and BALB/c mouse strains revealed host-dependent variation in immunity against G. duodenalis. C57BL/6, but not BALB/c mice exhibited increased duodenal CD4+ T cell presence following infection with G. duodenalis. Both mouse strains exhibited activated CD4+ and CD8+ T cells within the duodenum but C57BL/6 mice also mounted responses in other immune compartments such as the intestinal epithelium and Peyer's patches. We found that the intestinal microbiota is an important host factor that plays a central role in determining disease severity in the mouse model. Antibiotic treatment ablated intestinal CD8+ T cell activation and alleviated sucrase deficiency in G. duodenalis infected mice. G. duodenalis-activated CD8+ T cells exhibit cytotoxic potential by expressing granzyme A and IFN-&gamma. These cells, however, differentiate into an unconventional phenotype as they lack the surface expression of death receptor ligands FasL and TRAIL and do not express the canonical cytotoxic molecule granzyme B. An in depth understanding of the biology of Giardia-activated CD8+ T cells will lead to the development of novel therapeutic techniques aimed at alleviating diarrheal disease caused by Giardia. Further, identifying key host and parasite factors that contribute to clinical outcomes is imperative for effective control strategies
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
Investigating the Role of Myeloid Cells in Giardia Immunity
No full textPh.D.Human infections with Giardia duodenalis (giardiasis) is regarded as one of the most common human diarrheal disease worldwide with 280 million cases estimated to occur worldwide each year. This parasite lives a biphasic lifestyle either as a dormant cyst or vegetative trophozoite. Previous work has demonstrated that the cells and mechanisms of the adaptive immune system are critical for clearance of Giardia parasites. However, the innate system has not been as well studied in the context of Giardia infection, including what innate recognition mechanisms the immune system uses to initiate protective or pathologic immune responses during a Giardia infection. This dissertation explores a role for the Mannose Receptor and Macrophage Galactose Lectin receptor in protective immunity and also builds upon past studies that have examined the role of macrophages during Giardia infection. We report a mechanism for macrophage accumulation during Giardia infection that does not correlate with other intestinal diseases in which tissue resident macrophages proliferate in response to infection; however, these resident cells are dispensable for protection. This work also identifies three C-type lectin receptors - MR, MGL1, and MGL2 - that appear to be involved in the signaling of immune responses leading to protection from this parasite. We report that mast cell recruitment appears to be inhibited in MR-deficient mice, suggesting that parasite clearance may be defective due to the loss of mast cells during infection. We also show that MGL2 receptor is required for protective Giardia immunity as depletion of MGL2+ cells lead to a defect in parasite clearance. These cells also may be sources of IL-6, which is known to induce development of Th17 responses. Lastly, our preliminary data suggest that MGL1 found on Macrophages mediate production of IL-10. However, MGL1 engagement must occur with simultaneous co-stimulation by LPS that results in enhanced IL-10 production. This study contributes to a greater understanding of the interaction between Giardia and the immune system. Future studies delving into this host-pathogen interaction is certainly deserved as better therapies and treatments can be developed that can improve the health and well-being of those affected by giardiasis
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