1,720,985 research outputs found
Re-assessment of the type collections of corallinalean species (Corallinales, Rhodophyta) described by W. Ishijima (1942–1978).
No full textMany species of fossil coralline algae have been separated on the basis of only a few characters with slight or doubtful taxonomic significance. The analysis of the type material of the fossil coralline algal species is, therefore, needed in order to assess the taxonomic status and circumscription of these taxa. Wataru Ishijima has been one of the most prolific Japanese palaeontologists who worked on fossil calcareous algae from the western Pacific region. Ishijima described a large number of new taxa of fossil calcareous algae mostly belonging to the Corallinales from Eocene to Pleistocene sedimentary successions. An analysis of some Ishijima's types of Corallinales (Rhodophyta) described from 1942 to 1960, currently housed in the Institute of Geology and Paleontology, Graduate School of Science, Tohoku University, Sendai (Japan), is presented. For fourteen taxa changes were made to previously published statements of typification. Re-examination of the types from a modern perspective of coralline algal taxonomy shows that Hydrolithon taishakuensis (Ishijima) comb. nov (= Lithothamnium taishakuensis), Sporolithon kobamazimensis (Ishijima) comb. nov. (= Archaeolithothamnium kobamazimensis), Sporolithon kuboiensis (Ishijima) comb. nov. (= Archaeolithothamnium kuboiensis) and Sporolithon taiwanensis (Ishijima) comb. nov. (= Archaeolithothamnium taiwanensis) showed significant features justifying their use as species names in coralline algal taxonomy. No diagnostic characters occur in two types (L. nishiwadai, L. otsukiensis) and therefore the taxonomic disposition of these taxa remains unknown. Lithophyllum quadratum Ishijima is a heterotypic synonym of Lithophyllum incrustans Philippi. Lithoporella crassa Ishijima and Lithoporella hayasakai Ishijima are considered heterotypic synonyms of Lithophyllum prototypum (Foslie) Foslie, while Porolithon hanzawai Ishijima is a heterotypic synonym of Hydrolithon onkodes (Heydrich) Penrose and Woelkerling. Mesophyllum arakuraensis Ishijima is co-specific and has nomenclatural priority over M. contii Ishijima. However M. arakuraensis and M. contii do not show available evidence whether either might belong to Synarthrophyton instead of Mesophyllum. Lithothamnium ishizuchiensis Ishijima and L. kasedaensis Ishijima have no diagnostic features that can be used to ally them to any particular genus or species of Melobesioideae
Hydrolithon braganum sp. nov. (Corallinaceae, Rhodophyta), the first known exclusively fossil semi-endophytic coralline red alga
No full textHydrolithon braganum sp. nov., the first known exclusively fossil semi-endophytic species of Corallinaceae (Corallinales, Corallinophycidae, Rhodophyta), is based on material from IODP Expedition 310 cores of Last deglacial age (c. 20,000 – 10,000 years BP) from reef terraces around Tahiti, French Polynesia. A detailed morphological-anatomical account is provided, and the taxonomic position of the new species at generic and subfamily levels is considered in relation to recent molecular studies and consequent proposals for changes to the concepts of the subfamily Mastophoroideae and the genus Hydrolithon. Evidence is presented to show that the morphological-anatomical criteria proposed in recent molecular-based studies are untenable for circumscribing the subfamily Mastophoroideae and for separating genera called Hydrolithon and Porolithon. Both the Mastophoroideae and Hydrolithon are best recognized as polyphyletic at present. It is not essential to superimpose a morphological-anatomical based classification system on a set of lineages inferred from analyses of molecular sequence data sets that are based only on genes not known to control any of the morphological-anatomical characters currently used to delimit subfamilies or genera, especially when this results in proposals that do not account for all included taxa and are, to varying extents, not in accord with the International Code of Botanical Nomenclature. An alternative strategy is to direct molecular systematic research more towards discovering which genes are responsible for morphological-anatomical characters used to delimit taxa of coralline red algae and then to use data from those genes along with SSU, LSU, psbA, and COI data in analyses aimed at elucidating monophyletic lineages and producing classification systems in which all included taxa are accounted for, and given valid taxonomic names, and assigned to valid taxonomic ranks that are in accord with the ICBN
LE PRIME ALGHE ROSSE CORALLINACEE SEMI-ENDOFITE FOSSILI: RICERCHE DELL’IODP A TAHITI, POLINESIA FRANCESE
No full textMesophyllum macroblastum (Hapalidiaceae, Corallinales, Rhodophyta) in the Northern Adriatic (Mediterranean Sea) and a key to Mediterranean species of the genus.
No full textThe coralline red alga Mesophyllum (Hapalidiaceae) is recorded for the first time from the Gulf of Trieste (Northern Adriatic Sea) and gametangial plants of M. macroblastum are recorded for the first time from the Mediterranean Sea. A morphological-anatomical account is provided, including comparisons with specimens from the western coast of Italy and with published data. Distribution and habitat information, comparison with Mediterranean species of Mesophyllum, and a dichotomous key to Mediterranean species are included along with brief comments on other species in the genus known to produce volcano-like tetrasporangial conceptacles
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
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