1,720,982 research outputs found
New Amphora and Halamphora (Bacillariophyta) species from springs in the Northern Apennines (Emilia-Romagna, Italy)
No full textBackground and aims – The detailed analysis of algae and cyanoprokaryotes in a heterogeneous group of spring habitats (including all the different typologies) of the northern Apennines (Emilia-Romagna Region, Italy) revealed a new Amphora species in a small mountain flowing spring with low conductivity, and a new Halamphora species in a large, inland-saline (Triassic gypsum), fast flowing spring (Poiano spring). The present study aims to describe in detail these two new species found in contrasting spring types. Methods – This study is based on light microscopy (both fresh –for plastids – and prepared materials) and scanning electron microscopy observations, as well as a thorough morphological, physical, chemical, and biological characterization of the habitats. Key results – Amphora eileencoxiae sp. nov. is most similar to A. vetula (and allied taxa), and is characterized by the outline with acutely rounded, moderately ventrally bent ends, by the dimensions, and by the welldefined, semi-elliptic dorsal area. Halamphora poianensis sp. nov. is most similar to H. gasseae but differs by the higher stria density, the clearly ventrally bent ends, and the strongly developed dorsal raphe ledge. Conclusions – This is a contribution to the knowledge of the genera Amphora and Halamphora in mountain springs in understudied geographic areas and inland-saline springs, the species communities of which are likely insufficiently explored
Adding to Our Knowledge on the Diatom and Green Algae Biodiversity of Egypt: Some New-to-Science, Poorly Known, and Newly Recorded Species
Get PDFDuring our research on the diversity of diatoms and green microalgae from Egypt, four new-to-science, newly recorded, and poorly known species were retrieved from different Egyptian habitats. The new benthic diatom species Halamphora shaabanii A.A. Saber, El-Sheekh, Levkov, H. Saber et Cantonati sp. nov., which could not be identified using the currently available literature, was described from the high-conductivity, oasis lake Abu Nuss in the El-Farafra Oasis, located in the Western Desert of Egypt, employing both light (LM) and scanning electron (SEM) microscopy observations. A detailed comparison of the biometrically distinctive traits, and ecological preferences, of this new diatom species revealed sufficient differentiations from its morphologically most closely related species: H. atacamana, H. caribaea, H. ectorii, H. gasseae, H. halophila, H. mosensis, H. poianensis, and H. vantushpaensis. Ecologically, Halamphora shaabanii can tolerate relatively high nutrients (N and P) and prefers saline inland environments with NaCl water types. The araphid diatom Pseudostaurosiropsis geocollegarum was observed in the epilithic diatom assemblages of the River Nile Damietta Branch and identified on the basis of LM and SEM. From an ecological standpoint, P. geocollegarum seems to prefer elevated nutrient concentrations (meso-eutraphentic species), reflecting different human influences on the freshwater River Nile Damietta Branch. Based on the available literature, this is the first documentation of this freshwater diatom species for Egypt, and the second record for the African continent. Two green motile microalgae, Chlamydomonas proboscigera and Gonium pectorale, were isolated and identified from the terrestrial biomes of the arid habitat "Wadi El-Atshan" in the Eastern Desert of Egypt. C. proboscigera is reported herein for the first time in the Egyptian algal flora, while G. pectorale is poorly documented in the available literature. In light of our findings, the Egyptian habitats, particularly the isolated desert ecosystems, are interesting biodiversity hotspots and have a richer algal microflora than earlier anticipated. Furthermore, more in-depth taxonomic studies, using a combined polyphasic approach, are needed not only to foster our knowledge of the Egyptian and African algal and cyanobacterial diversity and biogeography, but also to be further used in applied environmental sciences
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
Reinvestigation of the type material for Odontidium hyemale (Roth) Kützing and related species, with description of four new species in the genus Odontidium (Fragilariaceae, Bacillariophyta)
No full textThe type materials of Odontidium hyemale, Odontidium anomalum var. longissimum (longissima), Diatoma hiemale var. maxima (maximum), Odontidium anomalum, and additional materials from the Faroe Islands, Austria, Switzerland, Italy and Macedonia were studied in LM and SEM. The nomenclature of these taxa is explained and original drawings presented. In addition, two new species, Odontidium rostratum and Odontidium apiculatum are described from Macedonia and Italy. The history and taxonomic changes of Odontidium are presented and its separation from Diatoma at the genus level explained in more detail
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