1,720,961 research outputs found
Bakteri Karbonatogenik Sebagai Agen Biosemen Untuk Alternatif Memperbaiki Retakan Beton
Get PDFBeton merupakan struktur bangunan dengan bahan dasar semen yang banyak mengandung CaCO3. Beton dapat mengalami retakan kecil, apabila dibiarkan akan mengakibatkan kerusakan struktur beton. Beberapa metode yang dapat digunakan untuk memperbaiki retakan kecil pada beton adalah mengisi dengan filler sintetik. Penggunaan filler sintetik kurang efektif karena aplikasinya lebih dari satu kali dan mudah terdegradasi. Bakteri karbonatogenik dapat membentuk CaCO3, sehingga dapat dijadikan alternatif pengganti filler sintetik. Metode ini lebih ramah lingkungan dan relatif lebih murah. Isolasi dilakukan dengan menggunakan metode sebar pada medium Calcium Carbonate Precipitation agar. Uji produksi kristal CaCO3 menggunakan metode penimbangan. Karakter kristal CaCO3 divisualisasi menggunakan X-Ray Diffraction dan Scanning Electron Microscopy. Identifikasi spesies bakteri dilakukan secara molekuler dengan marker gen 16S rRNA, rekonstruksi pohon filogenetik dengan menggunakan software MEGA 7.0. Keberadaan gen ureC dalam genom bakteri diketahui melalui PCR. Selanjutnya isolat bakteri karbonatogenik diaplikasikan pada retakan beton dan kemampuan isolat merekatkan retakan beton dicitrakan dengan mikroskop stereo.
Hasil isolasi mendapatkan 6 isolat bakteri yang mampu memproduksi kristal CaCO3 yaitu JA1, JB2, JB3, JA4, AK4, dan SU1. Keenam isolat mampu memproduksi kristal CaCO3 dengan berat diatas 275 mg/50 ml medium CCP cair. Terdapat lima isolat bakteri yang mampu memproduksi kalsit yaitu JA1, JB2, JA4, AK4, dan SU1, dan JB3 yang kristal dengan bentuk vaterit. Berdasarkan marka gen 16S rRNA isolat JA1 merupakan Bacillus huizhouensis, isolat JB2 merupakan Lysinibacillus boronitolerans, isolat JB3 merupakan Bacillus galactosidilyticus, isolat JA4 merupakan Sporosarcina spp., isolat AK4 merupakan Bacillus niacini, dan isolat SU1 merupakan Bacillus lentus. Pada deteksi gen ureC semua isolat uji menunjukkan pita DNA gen ureC dengan berat molekul 340 bp yang mengkode urease sub-unit α. Semua isolat mampu menutup retakan mikro (<0.25 mm) pada beton kecuali JB3, sehingga Isolat JA1, JB2, JA4, AK4, dan SU1 dapat digunakan sebagai agen biofiller retakan beton. Untuk meningkatkan kemampuan isolat tersebut dalam merekatkan beton dibutuhkan suatu perlakuan tambahan, berupa enkapsulasi sel pada matriks pembawa.
================================================================================================================== Concrete is a building structure with cement base material which contains large amount of CaCO3. Microcracks easily appears on concrete surface, yet if it left unchecked can lead to concrete structure damage. Some methods usually used in repairing microcracks on concrete surface are to fill in with the synthetic fillers. The use of synthethic fillers is considered less effective because it requires multiple activity to complete and it is easily degraded. Carbonatogenic bacteria can form CaCO3, so it can be more applicable as an alternative to synthetic filler. This method is considerably more environmental friendly and relatively cheaper. Isolation process was conducted by spread plate methods on Calcium Carbonate Precipitation agar. The test of CaCO3 crystal production was conducted by weighing method. Characters of CaCO3 crystal were visualized by using X-Ray Diffraction and Scanning Electron Microscopy. Identification of bacteria species was done molecularly with gene marker of 16S rRNA, the phylogenetic tree of species was reconstructed using MEGA 7.0. The existence of ureC gene in bacterial genome was carried out by PCR methods. Furthermore, isolates were applied on concrete cracks and the bacteria isolate ability in sealing cracks on concrete was visualized using stereo microscopy.
Isolation process obtained 6 bacterial isolates which capable to produce crystal CaCO3, those are isolate JA1, JB2, JB3, JA4, AK4, and SU1. All bacteria isolates are capable to produce CaCO3 crystals more than 275 mg/ 50 ml of liquid CCP medium. There are 5 bacterial isolates that capable to produce calcite form, those are JA1, JB2, JA4, AK4, and SU1, and only JB3 produces crystals with vaterite form. Regarding 16S rRNA sequences, isolate JA1 is Bacillus huizhouensis, JB2 isolate is Lysinibacillus boronitolerans, JB3 isolate is Bacillus galactosidilyticus, JA4 isolate is Sporosarcina spp., AK4 isolate is Bacillus niacini, and SU1 isolate is Bacillus lentus. The result of ureC gene detection represent all bacteria isolates showed 340 bp DNA band which encode α sub-unit of urease. All bacteria isolates capable to seal concrete microcracks (<0.25 mm), except JB3. So that, isolates JA1, JB2, JA4, AK4, and SU1 can be applied as biofiller agent to seal concrete microcracks. In order to increase the ability of bacteria isolates on sealing concrete microcracks, encapsulation into carrier matrix is required
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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