1,720,956 research outputs found
Isolation and characterization of viral nervous necrosis virus on newly established marine fish cell line and its pathogenicity in non-marine host
Get PDFIn Southeast Asia, the intensification of aquaculture industry has led to the occurrence of various infectious diseases. Virus diseases in particular, affecting especially the larval and juvenile stages, are the most suppressing factors for sustainable production of high value fish species such as seabass (Lates ca/carifer). Inevitable, because of lack of sensitive methods that could be used for diagnosis and the inadequacy of pathogen control, the aquaculture industry will continue to be plagued by these diseases. Currently, viral nervous necrosis (VNN) is one of fish diseases listed by the Office International des Epizooties (OlE) as a notifiable disease in the production of marine fish worldwide. Thus the main objective of the present study was to determine the role of VNN virus (VNNv) as a pathogen in the Malaysian aquaculture industry, with emphasis on virus isolation in susceptible cell line, virus identification using polymerase chain reaction (PCR) and identification of characteristic microscopy lesions in VNNv infections. A new cell line designated as Asian Seabass Brain (ASBB-1) was derived from the brain tissue of seabass cultured in Malaysia. This cell line was maintained in Leibovitz L-15 media supplemented with 10% fetal bovine serum (FBS). The ASBB-1 cell line was sub-cultured more than 60 times over a period of 15 months. This cell line consists predominantly of fibroblastic-like cells, which are able to grow at temperatures between 20°C and 30°C with an optimum temperature of 25°C. At 25°C, the growth rate of these cells increased as the proportion of FBS increased from 5 to 20% with optimum growth at 15% or 10% FBS. The ASBB-1 cell line was characterized by karyotyping, and chromosome number distributions were different with subcultures P20 and P50 producing 48 and 46 chromosome peaks respectively. The ASBB-1 cells showed 90% viability after recovery from one year storage in liquid nitrogen. The ASBB-1 cells up on characterization by peR using primer sets of microsatellite markers of Asian seabass (Lates ca/carifer) were shown to be similar to the cells from tissues of seabass at 250 bp. The VNNv isolate derived from seabass was tested positive for VNN by the 102000 Kit®. The isolate designated UPM08-1 M was used in the cell line infectivity study. The susceptibilities of ASBB-1 cell line isolate and the highly permissive commercial SSN-1 cells to UPM08-1 M were compared. The results showed that ASBB-1 cell line was susceptible to VNNv (RGNNV genotype) with typical cytopathic effect (CPE) manifesting mainly as rounding-up at1 day post infection (dpi), severevacuolationwithin3-5dpi and complete detachment within 7dpi. The VNNv-induced CPE was further elucidated by electron microscopy (EM). Under EM, the ASBB-1cellsexhibitedvacuolated degeneration with presence of viral inclusion-like bodies. The CPE of VNNv on ASBB-1cells was producedat a virus titer of 109 . 5 TCID50/ml. This indicated that the ASBB-1 cell line is highly susceptible for use in the isolation of VNNv. Biophysical and biochemical characterization of VNNv isolate was determined by heat treatment, UV irradiationand the stability under effect of chemical disinfectants. The VNNv isolate showed susceptibility to heat treatment at 60°C within 30 minutes with no viable virus after 1 hour. UV irradiation at an intensity of 440 mWrcm2 resulted in a reduction in virus titer after 8 minutes. The virus appeared relatively resistant to changes in pH ranging between 2 to 11 after 1 hour incubation at 25°C. Treatment with 2% formalin was not totally effective even after 6 hours. Iodine did not inactivate the virus. Molecular characterization of the tissue culture-propagated virus using RT-PCR and nested peR, showed positive amplifications of genome size of 460 bp and 220 bp respectively. The 220 bp nucleotides from the T4 region of the coat protein gene was sequenced and the phylogenetic analysis resultsshowed close resemblance between the UPM08-1 M strain andSBNNV and GPNNV2strains of Malaysianisolates.The local isolate of UPM08-1 M also showed phylogenetic similarity with other strains from South East Asia, while showed relatively distant similarity with other VNNv strains from the Middle East. Cold water VNNv strains isolated from Norway, Canada and USA were distant phylogenetic relations to the UPM08-1 M strain. Experimental infectivity study was also performed using fresh water guppy fish (Poecilia reticulata) as a model. Guppies were intra nasally infected with 0.1 ml of the UPM08-1M strain at a titre of 109.5 TCID5010.1ml. Although the artificial infection resulted in slight mortality (11%) occurring within 14 days post inoculation, the VNN-specific lesions such as necrosis and vacuolation in the target organs of brain and retina were evident. The presence of virus in infected brain and retina tissues was confirmed by transmission electron microscopy (TEM). The VNNv from experimentally infected guppy was successfully reisolated in ASBB-1 cells inoculated with homogenate of brain and retinas of the survivors. There was gradual increment of virus titer in the guppy throughout the experimental period. The results indicated that guppy fish could be infected with VNNv isolated from diseased seabass. In summary, the study successfully isolated VNNv using the ASBB-1cell line. Complete CPE of this cell line was observed within 5 - 7 dpi after infection with VNNv at producing considerable higher titer of 1095TCID5010.1ml. Thus ASBB-1 cells can be recommended for VNNv (RGNNV genotype) isolation and will be an important tool for future conduct of fish health assurance programs in the aquaculture industry. The study also showed that RT-PCR followed by nested- PCR is a sensitive technique for identification of VNNv isolated from sea bass. It was also shown that guppy fish could be experimentally infected with VNNv, thus can be used as a virus-infection model
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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