1,720,993 research outputs found
A new algorithm for the determination of differential taxa
No full textHow can we determine differential taxa in a vegetation data set? The new algorithm presented here uses an intuitive fidelity threshold based on relative constancy differences. It is tested on a simulated and a real data set. The results of the proposed algorithm are discussed in comparison with other methods used for the determination of differential taxa. The new algorithm defines each taxon in each group of relevEs as: (1) positively differentiating, (2) positively-negatively differentiating, (3) negatively differentiating, or (4) non-differentiating. Each taxon in a data set may be: (1) positively, positively-negatively or negatively differentiating for each group in the data set, (2) differentiating for some groups and non-differentiating for the remaining groups, or (3) non-differentiating for all groups in the data set. The new algorithm finds the relevE groups that are positively differentiated against other groups that are negatively differentiated. It reveals differentiating structures in the data set and thus makes quantification of the relations among and between different syntaxonomic ranks conceivable. As it distinguishes between different types of differential taxa, it might improve standards of typification in vegetation classification
Hellenic Woodland Database
No full textThe Hellenic Woodland Database (GIVD ID EU-GR-006) includes relevés from 59 sources, approximately, as well as unpublished relevés. In total 4,571 relevés have already been entered in the database, but the database is going to continue growing in the near future. Species abundances are recorded according the 7-grade Braun-Blanquet scale. The oldest relevés date back to 1963. For the majority of relevés (more than 90%) environmental data (e.g. altitude, slope aspect, inclination) exist. Relevés entered in the database represent both evergreen and deciduous forests, as well as scrubs and they belong (according to the original publications) to the classes Quercetea ilicis, Rhamno-Prunetea spinosae, Erico-Pinetea, Quercetea pubescentis, Querco-Fagetea, Vaccinio-Piceetea and Populetea albae. Most relevés (approximately 69%) concern northern Greece (floristic regions of northeastern, north-central Greece and northern Pindos), while the remainder concern the rest of Greek mainland as well as the islands
Vegetation types with Quercus ithaburensis subsp. macrolepis in Greece
No full textQuercus ithaburensis subsp. macrolepis is an important component of the Mediterranean flora, forming distinctive forests in the thermo and meso Mediterranean vegetation zone. The purpose of this study was to investigate the structure of Q. ithaburensis subsp. macrolepis communities of mainland and insular Greece, from a phytoecological point of view. The identification followed the Braun-Blanquet method and was based on 138 records from 19 areas. Seventeen vegetation types with Q. ithaburensis subsp. macrolepis have been distinguished in which the species holds a dominant, sub-dominant or differential role. All these groupments are attached to the class Quercetea ilicis distinguished in forest units of the Quercetalia ilicis (Quercion ilicis alliance) and pre-forest units of the Pistacio-Rhamnetalia alaterni (Ceratonio-Rhamnion and Pistacio-Rhamnion alliances) orders, while some very degraded communities, are difficult to be classified from a phytosociological point of view. Several diagnostic species of other phytosociological classes also appear, reflecting the impacts that these communities have undergone. The life form spectrum of these communities shows that therophytes are the most represented while for the chorological spectrum, the Mediterranean element is dominant.Theocharopoulos Michalis, Pantera Anastasia, Fotiadis Georgios, Papadopoulos Andreas. Vegetation types with Quercus ithaburensis subsp. macrolepis in Greece. In: Ecologia mediterranea, tome 46 n°1, 2020. pp. 17-40
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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