1,721,008 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
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
SPOROZOITE METAMORPHOSIS IN THE LIVER: INVESTIGATION OF THE ROLE OF PLASMODIUM GRASP AND VPS4 IN MICRONEME ELIMINATION
No full textThe Plasmodium metamorphosis during liver stage requires morphologic and metabolic changes including clearance of micronemes, previously required for hepatocyte penetration. Experimental evidence indicates that Plasmodium utilizes machinery associated with unconventional protein secretion (UPS) pathway for micronemal clearance from liver stage. The UPS-related pathway is involved in sequestering and eliminating damaged organelles in double-membrane vesicles from endoplasmic reticulum to plasma membrane, bypassing the Golgi, instead requiring autophagy related genes 8 (ATG8), Golgi reassembly and stacking protein (GRASP) and vacuolar protein sorting-associated protein 4 (VPS4), in a process called exophagy. In exophagy, GRASP has been identified to localize autophagosomes or multivesicular bodies (MVB) and mediate their tethering to the plasma membrane for cargo expulsion. To investigate the role of GRASP during liver stage development and autophagy, the laboratory engineered a Plasmodium mutant, named PbGRASP-KO (Plasmodium berghei GRASP knockout). Analysis of the parasite size between the PbGRASP-KO and WT, as the sporozoite develops into its exoerythrocytic forms (EEF), suggest that GRASP may be involved in early-mid stage schizogony however is dispensable for liver stage development as seen through successful schizogony of PbGRASP-KO with mid-stage developmental defects. From quantification of TRAP signal in IFA and its normalization to EEF volume, we observe that GRASP is non-essential for microneme elimination despite a smaller EEF at 22h p.i. Interestingly, previous investigations reveal colocalization of GRASP with ATG8 and VPS4, proteins essential for microneme compartmentalization and MVB biogenesis (hypothesized), respectively. To understand the association of GRASP with exophagy machinery, we tried to develop a PbGRASP-specific antibody in mice through intraperitoneal immunization. The antibody was generated against a synthetic multi-epitope protein of PbGRASP, designed, generated, and purified in laboratory. Western blot and immunofluorescence analysis of the antibody activity compared between WT and PbGRASP-KO suggests that these antibodies detect non-specific proteins rather than PbGRASP as seen from lack of clear and distinct puncta of PbGRASP in WT. In addition, we also tried to clone another Plasmodium mutant, named PbVPS4-KO (Plasmodium berghei VPS4 knockout) to investigate the role of VPS4 in Plasmodium development, however to no avail. We conclude that GRASP may have a role in Plasmodium mid-stage development, but further analysis is required for understanding its involvement in microneme clearance
A photoactivatable crosslinking system reveals protein interactions in the Toxoplasma gondii inner membrane complex
Get PDFThe Toxoplasma gondii inner membrane complex (IMC) is an important organelle involved in parasite motility and replication. The IMC resides beneath the parasite’s plasma membrane and is composed of both membrane and cytoskeletal components. Although the protein composition of the IMC is becoming better understood, the protein–protein associations that enable proper functioning of the organelle remain largely unknown. Determining protein interactions in the IMC cytoskeletal network is particularly challenging, as disrupting the cytoskeleton requires conditions that disrupt protein complexes. To circumvent this problem, we demonstrate the application of a photoreactive unnatural amino acid (UAA) crosslinking system to capture protein interactions in the native intracellular environment. In addition to identifying binding partners, the UAA approach maps the binding interface of the bait protein used for crosslinking, providing structural information of the interacting proteins. We apply this technology to the essential IMC protein ILP1 and demonstrate that distinct regions of its C-terminal coiled-coil domain crosslink to the alveolins IMC3 and IMC6, as well as IMC27. We also show that the IMC3 C-terminal domain and the IMC6 N-terminal domain are necessary for binding to ILP1, further mapping interactions between ILP1 and the cytoskeleton. Together, this study develops a new approach to study protein–protein interactions in Toxoplasma and provides the first insight into the architecture of the cytoskeletal network of the apicomplexan IMC.</div
SPOROZOITE METAMORPHOSIS IN THE LIVER: INVESTIGATION OF THE ROLE OF PLASMODIUM GRASP AND VPS4 IN MICRONEME ELIMINATION
Get PDFThe Plasmodium metamorphosis during liver stage requires morphologic and metabolic changes including clearance of micronemes, previously required for hepatocyte penetration. Experimental evidence indicates that Plasmodium utilizes machinery associated with unconventional protein secretion (UPS) pathway for micronemal clearance from liver stage. The UPS-related pathway is involved in sequestering and eliminating damaged organelles in double-membrane vesicles from endoplasmic reticulum to plasma membrane, bypassing the Golgi, instead requiring autophagy related genes 8 (ATG8), Golgi reassembly and stacking protein (GRASP) and vacuolar protein sorting-associated protein 4 (VPS4), in a process called exophagy. In exophagy, GRASP has been identified to localize autophagosomes or multivesicular bodies (MVB) and mediate their tethering to the plasma membrane for cargo expulsion. To investigate the role of GRASP during liver stage development and autophagy, the laboratory engineered a Plasmodium mutant, named PbGRASP-KO (Plasmodium berghei GRASP knockout). Analysis of the parasite size between the PbGRASP-KO and WT, as the sporozoite develops into its exoerythrocytic forms (EEF), suggest that GRASP may be involved in early-mid stage schizogony however is dispensable for liver stage development as seen through successful schizogony of PbGRASP-KO with mid-stage developmental defects. From quantification of TRAP signal in IFA and its normalization to EEF volume, we observe that GRASP is non-essential for microneme elimination despite a smaller EEF at 22h p.i. Interestingly, previous investigations reveal colocalization of GRASP with ATG8 and VPS4, proteins essential for microneme compartmentalization and MVB biogenesis (hypothesized), respectively. To understand the association of GRASP with exophagy machinery, we tried to develop a PbGRASP-specific antibody in mice through intraperitoneal immunization. The antibody was generated against a synthetic multi-epitope protein of PbGRASP, designed, generated, and purified in laboratory. Western blot and immunofluorescence analysis of the antibody activity compared between WT and PbGRASP-KO suggests that these antibodies detect non-specific proteins rather than PbGRASP as seen from lack of clear and distinct puncta of PbGRASP in WT. In addition, we also tried to clone another Plasmodium mutant, named PbVPS4-KO (Plasmodium berghei VPS4 knockout) to investigate the role of VPS4 in Plasmodium development, however to no avail. We conclude that GRASP may have a role in Plasmodium mid-stage development, but further analysis is required for understanding its involvement in microneme clearance
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