1,720,962 research outputs found
Decolorization of CI Direct Blue 201 Textile Dye by Native Bacteria
Get PDFWater pollution from untreated or partially treated textile dye effluents is one of the major problem concerns globally. Synthetic dyes extensively are used for textile dyeing process. They are highly recalcitrant to natural decolorization and degradation processes and will create drastic negative impacts on natural environment. Remediation of synthetic textile dyes through biological agents has been recorded as low cost and environmental friendly alternative for expensive chemical and physical treatment methods. Therefore the present study was aimed on the determination of CI Direct Blue 201 textile dye decolorizing ability by isolated bacteria strains. Among the 35 bacteria strains isolated from effluents of textile industries, five bacteria strains have shown remarkable decolorizing abilities on CI Direct Blue textile dye. The isolated bacteria were tentatively identified as Pseudomonas sp.1, Pseudomonas sp.2, Bacillus sp.1, Bacillus sp.2 and Micrococcus sp. by morphological features and biochemical tests. Decolorization kinetics of bacteria was recorded after 14 days of incubation with CI Direct Blue 201 dye treated at 75 ppm. Descending order of dye decolorization was resulted by Pseudomonas sp.2 (58.15 ± 0.92%), Bacillus sp.2 (55.02 ± 0.70%), Pseudomonas sp.1 (54.73 ± 1.99%), Micrococcus sp. (51.86 ± 0.49%) and Bacillus sp. 1 (51.55 ± 0.74%) at 280C respectively. Descending decolorization potential was shown by all bacteria as a response for the ascending initial concentration of dye. The highest decolorization of dye was recorded by Pseudomonas sp.2 as 67.93 ± 1.23% at 50 ppm. High decolorization percentages were obtained when bacteria were incubated at 320C compared to 280C and 240C. Results of the present study revealed that isolated bacteria will be successful aspirants for remediation of synthetic textile dyes as an ecofriendly bioremediators to consider for green application approaches. However further studies are needed to understand their dye degradation mechanism in natural environment.KEYWORDS: Bioremediation; dye decolorizing bacteria; CI Direct blue 201; Azo dy
Seasonal changes in the abundance of biological agents killing Microcystis aeruginosa in a hypereutrophic pond
No full textSeasonal changes in abundance of the heterotrophic flagellates Polytomella sp., rotifersCephalodella sp., Brachionus caliciflorous and the testate amoeba Penardochlamyssp. as grazers, cyanophages and algicidal bacteria as infectious agents on mortality ofcyanobacterium, Microcysis aeruginosa was intensively studied in a hypereutrophic pond fromSeptember to November 2000. Abundance of the rotifers Cephalodella sp., B. caliciflorousand the Penardochlamys sp. were relatively high with large fluctuations. The cell density of M.aeruginosa ranged between 3.0 x 105 to 1.9 x 107 cells ml-1, whereas those of algicidal bacteriawere between 0.3 x 12 to 3.7 x 102 PFU ml-1 and cyanophages were between 0.9 x 103 to7.1x 103 PFU ml-1. Algicidal bacteria were relatively high with fluctuation between0.3 x 104 to3.7 x 104 PFU ml-1 and bacterial peaks were followed with M. aeruginosa peaks. Occationalcyanophages peaks on 2 and 20 October were followed by sudden collapse of M.aeruginosabloom. Percentages of M. aeruginosa cells in food vacuole of Penardochlamys sp.was high(77%) during September following increase of the M. aeruginosa cell density. The flagellatePolytomella sp. was increased to a peak (2.5 x 105 indi. M-1) from 10 to 17 November withdecrease of M. aeruginosa cell density. The percentage of B. caliciflorous individuals ingestingcolonies of M. aeruginosa during the bloom period was significantly high (t-test, P Percentageof testate amoebae Penardochlamys sp. ingesting M. aeruginosa cells was very high (?77%)during the bloom period. The food vacuoles of Penardochlamys sp. contained only Microcysisindicating its specific preference of Microcysis. The overall results of the study suggest thegrazers’ protozoa; Polytomella sp., and the testate amoeba Penardochlamys sp., zooplankton;Cephalodella sp. and Brachionus caliciflorous, cyanophages and algicidal bacteria successivelyinvolved in suppressing M. aeruginosa bloom in a freshwater environment.Key words : Microcysis aeruginosa, cyanophages, algicidal bacteria, Penardochlamys sp.,Cephalodella sp. and Brachionus caliciflorou
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
Water quality and microbial contamination status of groundwater in Jaffna Peninsula, Sri Lanka
No full textIn Sri Lanka, among 2588 Salmonella positive cases, the highest incidences were recorded from Jaffna peninsula during 2005 to 2013. Therefore, the present study aimed to identify the microbiological and chemical contamination status of groundwater (40 well water) sources in Jaffna during November 2016. The total coliform, E. coli, Salmonella spp. and Shigella spp. along with some physico-chemical parameters of groundwater were studied. The results revealed that entire peninsula was contaminated with total coliform and E. coli bacteria and the parameters recorded were not within the WHO and SLS (Sri Lanka Standards) drinking water quality standards. 38% of sampling locations were positive for Salmonella spp. and among them six sampling locations were being used for drinking purposes. The results of the study correlates with the statistics of typhoid cases recorded in Jaffna. Results of the study also revealed that around 80% of wells were not within the values specified in guidelines of the SLS for drinking water quality on electrical conductivity. Further, 15% of wells recorded greater than 10 mgꞏdm–3 nitrate, which is still below the SLS drinking water standards (45 mgꞏdm–3). According to the water quality data, PCA analysis showed that Jaffna town, Nallur, Tellippalai and Kopay DS divisions has similar characteristics for water quality
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
Evaluation of Groundwater Quality in Five Grama Divisions of Maharagama Urban Area Using Groundwater Quality Index (WQI)
Get PDFMaharagama urban area is a heavily populated area in Colombo district. Groundwater in this area is having a great vulnerability for pollution by anthropogenic activities. The present study was carried out to monitor some important water quality parameters, to evaluate the quality of groundwater in the study area using a Water Quality Index (WQI) and to compare the water quality between Grama Niladari (GN) divisions in the study area. Five GN divisions (Jambugasmulla, Gangodawila south B, Wijerama, Navinna and Wattegedara) were selected for the study. 55 wells were sampled during the study. The resulted WQI values in groundwater ranged from 17.08 to 280.91. The results revealed that the water quality of the wells deviate from excellent to very poor quality. The nitrate concentration was high (>45mg/l) in some wells. Considering all the water quality parameters, the poorest water quality was recorded in Navinna GN division. It was observed that unregulated garbage dumping, uncontrolled application of organic and inorganic fertilizers, constructing toilet pits very close to wells and unregulated human settlements have been increasing in the study area. KEYWORDS: Ground water, nitrate, water quality, water quality inde
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