1,720,954 research outputs found
ISOLASI SENYAWA ALKALOID DARI KULIT BATANG Dehaasia lancifolia BL. Ridl
Get PDF ABSTRACT Dehaasia lancifolia plant from family of Lauraceae and base on the phytochemical survey in Malaysia and West Sumatera containing alkaloid compounds. The alkaloid compounds containing in Dehaasia lancifolia BL. Ridl has not been isolated and from chemotaxonomy aproximation gave an indication that alkaloid structure not quite difference with one of Phoebe genus of the same family wich has been isolated. The isolated alkaloid compound was obtained in amorf solid phase and yellowish colored in relatively high concentration. The bromide salt of this compound melt at 261°-264°C. UV spectrum indicated the maximum absorbtion band at wavelength 282 and 204 nm wich indicated the chromophoric group of tetrahydroquinoline. IR spectrum shown an absorbtion band at: 3550 cm-1 (stretching C-N), 3030 cm-1 (C-H aromatic), 2930 cm-1 (-CH2- stretching), 2860 (CH aliphatic stretching), 1660-1600 cm-1 (C=C aromatic), 1530 cm-1 (C=N aromatic), 1070 cm-1 (C-O-C stretching) and brommide salt shown an absorbtion band at 2680 cm-1 (>N+-H stretching) and without OH group in this molecule Keywords: dehaasia lancifolia BL. Ridl, alkaloid, spectrophotometer UV and IR</jats:p
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
ISOLASI FLAVONOID DARI BIJI KAKAO (Theobroma cacao)
Get PDFTelah dilakukan isolasi senyawa flavonoid dari biji cacao (Theobroma cacao) pada fraksi etil asetat. Isolasi dilakukan dengan maserasi menggunakan metanol dan dilakukan fraksinasi dengan n-heksan dan etil asetat. Fraksi etil asetat dilakukan kolom kromatografi bertekanan tinggi (flash colom chromatografphy). Hasil isolasi berupa kristal bewarna kuning dan telah memberikan noda tunggal dengan beberapa eluen menggunakan kromatografi lapisan tipis (TLC). Kromatografi kertas dua arah didapatkan Rf 0,45 menggunakan eluen BAA (4:1:5) dan Rf 0,48 menggunakan eluen asam asetat 15%. Spektroskopi ultraviolet dengan menggunakan pelarut metanol memberikan serapan pada ?maks 281 dan 328 nm. Menggunakan pereaksi geser NaOCH3 serapan ?maks 290 dan 411 nm, AlCl3 ?maks 293 dan 385 nm dan HCl ?maks 280 dan 330 nm, NaOOCCH3 serapan ?maks 281 dan 330 nm dan H3BO3 serapan ?maks 295 dan 381 nm. Spektroskopi infra merah (IR) memberikan serapan pada angka gelombang 3407,6; 2360,4; 1663,3; 409,8 cm-1. Berdasarkan data tersebut diperkirakan senyawa hasil isolasi dari ?maks 281 dan 328 nm adalah suatu flavonol yang tersubstitusi dengan gugus hidroksi pada posisi 7, 3’ dan 4’
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
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