1,720,996 research outputs found
DNA Metabarcoding as a tool for soil’s biodiversity assessment in organic and conventional agroecosystems
No full textElucidating how agricultural practices affect soil invertebrate communities is of relevant importance. In
the present study, using DNA metabarcoding, soil invertebrate communities of selected farms in the Po
Valley (Italy) were assessed in order to address the following questions: i) is the structure of soil
invertebrates’ communities different between organic and conventional farms? ii) To which extent are
field use (crop vs stable meadow) and field margins affecting these communities? Soil samples were
collected from organic and conventional farms in different periods of the year, covering the margins and
three levels towards the centre of fields of stable meadow and barley of both farms. DNA was extracted
from soil samples and a fragment of the cox1 gene amplified using three different pairs of primers;
amplicons were sequenced using Illumina Miseq. Raw sequences were analysed using Qiime and
ecological and statistical analyses were performed with R in order to address the above-mentioned
questions. The recovered invertebrate’s communities were dominated by Arthropoda (~ 80% of the OTUs
in each sample), a total of 831 OTUs (Insecta 51%, Arachnida 18% and Mollusca 14%) formed the core
diversity present in all the analysed samples. α-diversity indices were not significantly different between
the two farming strategies in terms of OTUs richness, Shannon index and Pielou’s evenness. β-diversity
analyses showed the field margins invertebrate communities were different from the inner field
communities. In conclusion, DNA metabarcoding represented a suitable method for soil invertebrates’
biodiversity estimation. The recovered communities are significantly affected by the crop and the
localization in the field (margin vs center). In addition, the role of field margins as a diversity reservoir is
increased in cultivated fields (barley), while in stable meadows fields, the interactions between the
margins and the center of the field are lower
Assessing the impact of agricultural strategies on soil Artropods: a case study using environmental DNA
Full text linkElucidating how agricultural practices affect soil arthropod’s communities is of relevant for both scientific and economic interests. Thus, using DNA metabarcoding approach, Arthropods communities inhabiting soil of organic and conventional farms were characterized. Soil samples were collected from organic and conventional farms, covering the margin and three levels towards the center of a stable meadow and a barley field in both farms; each sample consisted of 10 homogenized cores of soil (~560 cm3), sampling was performed in spring, summer and autumn Soil texture, pH, N and C parameters were measured. DNA was extracted from three replicates of each soil sample. A fragment mitochondrial cox1 was amplified using three primer pairs and sequenced using Illumina Miseq. Raw sequences were processed and analyzed using Qiime to obtain Operational Taxonomic Units (OTUs) table. Approximately 75% of the obtained reads were identified as Animalia, and among these ~80% as Arthropods. α-diversity indices barley field in conventional farming were significantly lower (OTUs= 854, H'= 5.34±0.53, Pielou’s evenness= 0,77±0,06) comparing with the other samples (OTUs> 1100, H'> 6 and Pielou’s evenness> 0,8). Fitting the farming system, the field, position as factors in NMDS showed that Arthropods communities were not affected by the collecting season and the farming system (organic vs conventional), instead crop vs stable meadows and the position in the field (margin vs middle) have a strong effect. Soil properties affected the Arthropods communities, especially the pH on Chilopoda and Diplopoda and the C/N ratio on Arachnida and Insecta. Our results pointing out that the strategy of farm management does not affect the arthropod communities of the soil as much as the soil properties itself, while the position in the filed had a major effect, highlighting the importance of green corridors for maintaining the soil biodiversity and the agroecosystem functioning
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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