1,720,956 research outputs found
Evaluation of plant efficiency in a constructed wetland receiving treated tannery wasterwater.
No full textA free water surface pilot-plant was constructed with the aim to reduce the high concentrations of sulfate, sodium, chloride and chromium in treated tannery wastewater. The CW was composed of two cells, one planted with Phragmites australis and the other with Carex ssp. Plants were sampled monthly to evaluate the effects of wastewater on growth and the accumulation of Cr, S, Na, Cl in different plant organs.
No effects of the wastewater quality on fresh and dry weight of plants and on leaf pigment content were observed. Accumulation of cromium, sulfur, sodium and chloride was higher in roots than in shoots of both plant species. Mean Cr and S contents were recorded to be higher in P.australis plants (74.3 μg g-1 d.w. for Cr, 16.9 mg g-1 d.w. for S).than in Carex ssp. plants (16.2 μg g-1 d.w. for Cr, 12.1 mg g-1 d.w. for S). Carex ssp. plants accumulated more Na (17.4 mg g-1 d.w.) and Cl (22.7 mg g-1 d.w.) than P.australis ,12.6 mg g-1 d.w. and 18.7 mg g-1 d.w., respectively.
P.australis plants seem to be more suitable for removal of pollutants from the tannery wastewater, due to the greater biomass produced
Confronto della capacità di rimozione del cromo tra quattro specie di salice
No full textA causa dell’ampio uso industriale del cromo e dello smaltimento dei residui di lavorazione, si è incominciato a considerare questo metallo come un serio inquinante ambientale.
Il cromo si trova in natura con differenti stati di ossidazione da Cr2- a Cr6+, dei quali le forme trivalente (Cr3+) ed esavalente (CrO42-) sono le più stabili e comuni.
Il cromo trivalente a piccole concentrazioni è essenziale per la vita degli animali e degli esseri umani; è coinvolto, infatti, sia nel metabolismo glucidico sia in quello lipidico, e risulta 10÷100 volte meno tossico del Cr esavalente. Tuttavia esso può risultare tossico a concentrazioni elevate.
Lo studio ha lo scopo di indagare l’effetto di due differenti trattamenti con cromo trivalente alle concentrazioni di 100 μM e 300 μM su accrescimento, contenuto in pigmenti fotosintetici, attività fotosintetica, conduttanza stomatica, traspirazione e contenuto di cromo in radici e foglie di quattro specie di salice: S. alba sub. typica (L.), S. elaeagnos (Scop.), S. fragilis (L.) e S. matsudana var. tortuosa (Koidzumi).
Le piante ottenute da talee sono state fatte crescere su un substrato di sabbia di quarzo e agriperlite e irrigate con una soluzione nutritiva completa.
A 30 giorni dal trapianto sono iniziati i trattamenti con CrCl3 che si sono protratti per 26 giorni.
I risultati hanno evidenziato una diminuzione significativa dell’accrescimento solo in S. alba nel trattamento a 300 μM rispetto al controllo. Per quanto riguarda il contenuto in pigmenti fotosintetici non si sono riscontrate differenze significative tra i trattamenti ed il controllo per nessuna delle quattro specie analizzate, mentre alcune differenze sono state osservate nell’andamento della traspirazione, della conduttanza stomatica e nell’attività fotositetica. Inoltre, sono state evidenziate importanti differenze nella capacità di accumulo del Cr tra le quattro specie di salice considerate
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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
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