1,720,957 research outputs found
Selenium levels in Lebanese environment
No full textVery limited research has been conducted on selenium (Se) in Lebanese soils and forage crops but no work has been done on Se in water and locally produced vegetables and grains. This research was conducted in order to quantify Se levels and its availability in agricultural soils, vegetables and grains in Lebanon. Sixty-six (66) soil samples were collected from 33 selected sites in Lebanon: the Bekaa Valley, coastal and mountainous regions. Thirteen (13) different plant types (86 samples) were sampled from the same locations. Also, 13 spring water and 10 bottled water samples were collected. Soil samples were analyzed for their physical and chemical properties. Selenium was extracted from soils with: deionized-distilled water (Soluble-Se), KH2PO4-0.1M (MKP-Se) and concentrated (HNO3+HCl) mixture (acid-Se). Plant Se was extracted by acid digestion on a hotplate. Selenium concentrations were measured by the inductively coupled plasma-mass spectrophotometer (ICP-MS). The values of Soluble-Se, MKP-Se and acid-Se ranged between 47 and 142, 147 and 400, and 1749 and 4713μg-kg, respectively, with average values of 95, 306, and 3118μg-kg and at a ratio of 1:3:30. Thus, Se extracted with deionized-distilled water is a good indicator for Se availability in the studied soils. The average Se concentration in plants was in the following order: radishandgt;lettuceandgt;cucumberandgt;cabbageandgt;parsleyandgt;alfalfaandgt;onion (leaves)andgt;broccoliandgt;tomatoandgt;mintandgt;chickpeasandgt;wheatandgt;onion (bulbs). The Se levels in water samples were in the safe range (less than 50μg-L) and ranged between 2.14 and 17.6μg-L. The levels of Se in the three soil extractants were positively correlated with each other and with organic matter content, salinity and phosphorus (P). Selenium levels in plant samples were positively correlated at a 0.01 significance level with clay and P content. © 2010.Al-Saleh Iman A., 1999, Journal of Environmental Pathology Toxicology and Oncology, V18, P37; Bashour I, 2007, METHODS ANAL SOILS A; BISBJERG B, 1969, PLANT SOIL, V31, P287, DOI 10.1007-BF01373572; CHAO TT, 1989, SOIL SCI SOC AM J, V53, P385; Dhillon KS, 2005, AUST J SOIL RES, V43, P639, DOI 10.1071-SR04166; ELRASHIDI MA, 1987, SOIL SCI, V144, P141, DOI 10.1097-00010694-198708000-00008; FAO, 1992, SOILS B, V65; Fordyce F. M., 2005, ESSENTIALS MED GEOLO, P373; GONDI F, 1992, BIOL TRACE ELEM RES, V35, P299, DOI 10.1007-BF02783773; Hawkesford MJ, 2007, J CEREAL SCI, V46, P282, DOI 10.1016-j.jcs.2007.02.006; JOHNSON CC, 2004, CR04016N BRIT GEOL S; Kabata Pendias A., 2001, TRACE ELEMENTS SOILS, P241; Lteif A, 2005, PLANT NUTR FOOD SECU, P716; McNeal J.M., 1989, SSSA SPECIAL PUBLICA, V23, P1; Mikkelsen R.L., 1989, SPEC PUB SOIL SCI SO, V23, P65; [NAS NRC], 1983, SEL NUTR; Oldfield JE, 1999, WORLD ATLAS SELENIUM; Selim HM, 2001, HEAVY METALS RELEASE, P191; Tan KH, 1989, SOIL SAMPLING PREPAR; Terry N, 2000, ANNU REV PLANT PHYS, V51, P401, DOI 10.1146-annurev.arplant.51.1.401; Wang MC, 2003, CHEMOSPHERE, V52, P585, DOI 10.1016-S0045-6535(03)00240-60
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
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