1,720,964 research outputs found
Optimisation of citric acid production from a novel strain of aspergillus niger by submerged fermentation
No full textFungi isolated from various rotten fruits and vegetables were screened for the capability of producing citric acid. Aspergillus niger (A. niger) was obtained in the decayed onion peels and denoted as KON13 and this fungi strain was used in the production of citric acid by submerged fermentation. Critical process parameters affecting the fermentative citric acid production were investigated, including the types of carbon source, initial pH and initial sugar concentration in the fermentation medium. It was demonstrated that sucrose is the best carbon source in the fermentation process for this new isolate with a produced citric acid concentration of 1.76 g/L as compared to glucose and lactose. The study of the effect of initial pH within the range of pH 2 to 7 in the fermentation medium revealed that a maximum concentration of 1.82 g/L of citric acid was produced at an initial pH of 2. The highest citric acid concentration of 2.02 g/L was achieved at an initial sugar concentration of 140 g/L in the fermentation medium. This present study has demonstrated that the novel isolate strain of A. niger from onion peels is capable of producing citric acid with optimum concentration when sucrose was selected as the carbon source in the fermentation process, and at the fermentation conditions where initial pH of 2 and initial sugar concentration of 140 g/L in the fermentation medium
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
Isolation of citric acid-producing Aspergillus niger from soil and organic wastes
Get PDFIntroduction of new Aspergillus niger strains that are more productive than those currently in use is one of the important steps in promoting more effective commercial citric acid production. The present study was conducted to isolate and characterise indigenous A. niger from selected soil and organic wastes such as soil with buried bamboo, soil with bamboo on the surface, soil under cattle grazing, mango orchard soil, rotting plum fruit and rotting bread. Morphological identification of A. niger was based on the length and width of the conidiophores, vesicles, phialides, and spores. Citric acid-producing Aspergillus isolates were screened based on the citric acid production index. The present study found that the highest fungal spore counts (3.35±0.15 x 107 spores/g sample) were obtained from soil under cattle grazing, as were the highest A. niger counts (7.25±0.05 x 106 spores/g sample). The lowest total fungal counts came from rotting plum fruit (4.70±0.10 x 105 spores/g sample). A total of 14 isolates were collected, with five (NSA03, NSA06, NSA09, NSA12, and NSA14) showing morphological similarities with the reference isolate, A. niger Tiegh. All isolates were able to produce citric acid, but with varying efficiencies according to their citric acid production indices. The soil under cattle grazing area found to be the best site for sampling and isolation for citric acid-producing A. niger by using Czapek-Dox as a medium of isolation
Serum biochemical properties and liver morphology of broiler chicken as affected by feeding Misai kucing (Orthosiphon stamineus) as supplement diet
Get PDFTo evaluate the effects of ground leaf of Misai kucing ( Orthosiphon stamineus ) as a dietary supplement on serum biochemical parameters and liver morphology. One hundred and sixty one-day old male broiler chickens (n=160) were distributed into four treatment groups, with five replicates of eight birds in each group: the control group (diet without additives); the group dietary treatments, Diet OS2 (Basal diet + 2g/kg O. stamineus ); Diet OS4 (Basal diet + 4g/kg O. stamineus ) and Diet OS8 (Basal diet + 8g/kg O. stamineus ). After 42 days, 40 birds were randomly selected for serum biochemical profile analysis involving pancreatic, renal, and hepatic functions (urea, sodium, potassium, chlorine, aspartate transaminase (AST), alkaline transaminase (ALT), alkaline phosphatase (ALP), glucose, cholesterol, triglycerides, total protein, albumin, and globulins). Present study found that serum levels of cholesterol, triglycerides, urea, AST, ALT and ALP were significantly lower suggesting that the O. stamineus ground leaf possibly do not cause kidney and liver impairment, mainly, at the higher dosage (8g/kg). Present study concluded that the broiler chicken fed O. stamineus ground leaf at a rate 8 g/kg was the most promising dietary supplement to enhance health without deleterious effects on serum biochemical properties and morphological components of liver. In addition, it reduces abdominal fats and serum cholesterol. This study has provide evident that medicinal plant, O. stamineus can potentially substituted the use of additive synthetic
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