1,720,970 research outputs found
First palynological record for the Lebombo Basin, South Africa with implications for Guadalupian (middle Permian) palaeofloras and palaeoenvironments
No full textThe Permian Emakwezini Formation (Adelaide Subgroup, Beaufort Group, Karoo Supergroup) of the Lebombo Basin in northeastern South Africa, has previously yielded two macrofloras comprising mostly Glossopteridales and sphenophyte taxa. Here we describe a palynological association from the Somkhele Mine locality in KwaZulu-Natal, the first recorded for the Emakwezini Formation, and for the basin as a whole. The association consists of a palynoflora with a good to fair quality of preservation, from which 142 species are identified. Elements of stratigraphic value are highlighted (e.g., Falcisporites stabilis, Guttulapollenites hannonicus, inter alia), which, when contrasted with the palynostratigraphic schemes known for the Main Karoo Basin and neighbouring basins, suggest a Guadalupian age for the deposits. Furthermore, the microflora points to a higher plant diversity than documented in the macrofloral record. The occurrence of Filicophyta, Lycophyta, Cordaitales, Coniferales, Peltaspermales and Voltziales, suggests the presence of complex forests, with a diversity of tree taxa. These inferences about the parent flora have expanded our understanding of the forests in the Lebombo Basin during Permian times and have helped to clarify the temporal and regional floristic relationships of floras in the Main Karoo Basin.Fil: Balarino, María Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Gutierrez, Pedro Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Prevec, Rose. Rhodes University. Albany Museum.; SudáfricaFil: Ruffo Rey, Lautaro Julián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Cariglino, Barbara. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin
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
A structural re-interpretation and revision of the type material of the glossopterid ovuliferous fruitification Scutum from South Africa
No full textThe Early Permian glossopterid fructification Scutum, described by Edna Plumstead in the 1950s from the Vereeniging locality in the Karoo Basin of South Africa, was one of the first glossopterid seed-bearing organs to be found in organic attachment to Glossopteris leaves. Examination of the type material necessitated a revision of this plant fossil genus and a re-evaluation of described South African species. Key characteristics of the genus are the broad and prominent wing, and a low receptacle length to width ratio (<2:1). Specimens of South African Scutum are currently attributed to three species, from two localities, but display intergrading morphological features that can be reasonably accommodated within a single species, S. leslii. Three-dimensional interpretation and reconstruction of impression fossils of Scutum fructifications preserved in attachment to Glossopteris leaves confirms that the seed-bearing surface of the receptacle faces the adaxial surface of the subtending leaf. The nature of the seed scars on the receptacle and their relationship to the peripheral wing of the fructifications is clarified
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
The architecture of Permian glossopterid ovuliferous reproductive organs
No full textA historical account of research on glossopterid ovuliferous reproductive structures reveals starkly contrasting interpretations of their architecture and homologies from the earliest investigations. The diversity of interpretations has led to the establishment of a multitude of genera for these fossil organs, many of the taxa being synonymous. We identify a need for taxonomic revision of these genera to clearly demarcate taxa before they can be used effectively as palaeobiogeographic or biostratigraphic indices. Our assessment of fructification features based on extensive studies of adpression and permineralized fossils reveals that many of the character states for glossopterids used in previous phylogenetic analyses are erroneous. We interpret glossopterid fertiligers to have been borne in loose strobili in which individual polysperms represent fertile cladodes of diverse morphologies subtended by a vegetative leaf or bract. Polysperms within the group are variously branched or condensed with ovule placement ranging from marginal to abaxial, in some cases occurring on recurved branchlets or in cupule-like structures. Glossopterid polysperms of all types are fringed by one or two ranks of wing-like structures that may represent the remnants of megasporophylls that were, ancestrally, developed on the fertile axillary shoot. Glossopterid fertiligers have similarities to the condensed bract/ovuliferous scale complexes of conifer cones, but comparisons with Mesozoic seed-ferns are hindered by insufficient data on the arrangement and homologies of the ovulebearing organs of the latter group. Nevertheless, glossopterid polysperms differ from the ovuliferous organs of Mesozoic seed-ferns by longitudinal versus transverse folding, respectively.Also funded by the National Science Foundation [project #1636625]; University of the Witwatersrand; Rhodes University; the DST-NRF Centre of Excellence in Palaeosciences and the NRF African Origins Platform [UID: 98822]</p
- …
