1,721,029 research outputs found
Sphaerocarpos ibericus sp. nov. (Sphaerocarpaceae), a new European liverwort species that includes S. stipitatus auct. eur. non Lindenb
No full textIntroduction: Specimens of Sphaerocarpos collected during 2022 from the central Iberian Peninsula did not match any previously known species of this genus. Examination of other herbarium material revealed three identical specimens from three different localities in Spain. These were also morphologically identical to Portuguese specimens previously identified as S. stipitatus, a southern hemisphere and Himalayan species that in fact is different from these Portuguese plants. Methods: The morphology of the newly collected specimens was compared with that of the known European species plus descriptions of South African plants of Sphaerocarpos stipitatus. A phylogenetic analysis based on the nuclear gene 26S and plastid psbA and rbcL regions was performed to investigate its relationships in the genus. Key results and conclusions: Based on morphological and molecular data, we describe the plant as a new species of bryophyte, Sphaerocarpos ibericus M.Infante, Luceño, Quirós-de-la-Peña, Míguez, J.Muñoz & Heras, hitherto an Iberian endemic. It is diagnosed by having cylindrical female involucres with a partially bistratose wall whose inner cells are finger-like and arranged in more-or-less definite ribs in the medial part of the involucre, and the distal part of its spores covered with complete areolae larger at the centre of the spores than on their sides, gradually becoming incomplete and with the remaining lamellae transforming into ridges towards the line where the individual spores of the tetrad are joined. According to published illustrations, Portuguese specimens identified as S. stipitatus pertain indeed to the new species, and therefore S. stipitatus auct. eur. non Lindenb. should be removed from the European liverwort flora.Peer reviewe
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
On the genus Rosa (Rosaceae) in the Canary Islands: proposal of three new species
No full textThe genus Rosa has been cursory studied in the Canary Islands in such a way that there are multiple
records for different islands since early 20th century, but no taxonomic review. Historically, five taxa have been cited:
Rosa tomentella Léman (also R. tomentella Bak.), R. canina L., R. rubiginosa L., R. micrantha Borrer ex Sm. and Rosa dumalis Bescht. subsp. teydensis Weller & H. Reichert. This note intends to review the occurrence of those taxa and to circumscribe Canarian populations into species. Considering the current taxonomic treatment adopted for European roses in the last six decades, we propose a minimum of five different species of sect. Caninae for the archipelago, of which two have already been cited: R. micrantha and R. rubiginosa. Some key characters found in other populations distributed in Gran Canaria and La Gomera better fit into the concept of R. nitidula Besser.
Additionally, we consider three new species on ancient high volcanoes of La Palma (R. roque-muchachensis, sp. nov.), El Teide (R. cannadas-teydensis, sp. nov.) and (R. gran-canariae, sp. nov.) showing a combination of characters found neither in Europe nor in the other populations of the Canary Islands. In any case, phylogenetic studies already in progress will shed light to propose evolutionary relationships and a more natural classification of Rosa in the Canary
Islands.[ES] El género Rosa ha sido estudiado someramente en las Islas Canarias, de tal manera que hay numerosos registros para diferentes islas desde principios del siglo XX, pero ninguna revisión taxonómica. Históricamente se han citado cinco táxones:
Rosa tomentella Léman (también R. tomentella Bak.), R. canina L., R. rubiginosa L., R. micrantha Borrer ex Sm. y R. dumalis Bescht. subsp. teydensis Weller & H. Reichert. Esta nota pretende revisar la presencia de estos táxones y circunscribir las poblaciones canarias en especies. Sobre la base del tratamiento taxonómico actual adoptado para las rosas europeas en las últimas seis décadas, proponemos un mínimo de cinco especies de la sección Caninae para el
archipiélago, de las cuales solo dos ya han sido citadas: R. micrantha y R. rubiginosa. Algunos caracteres clave encontrados en otras poblaciones distribuidas en Gran Canaria y La Gomera encajan en el concepto de R. nitidula Besser. Además, consideramos tres nuevas especies en los volcanes más altos y antiguos de las Islas Canarias: La Palma (R. roque-muchachensis, sp. nov.), El Teide (R. cannadas-teydensis, sp. nov.) y Gran Canaria (R. grancanariae,
sp. nov.). Las tres muestran una combinación de caracteres que no se encuentran ni en Europa ni en el resto de las poblaciones de Canarias. En cualquier caso, los estudios filogenéticos ya en marcha arrojarán luz para proponer relaciones evolutivas y una clasificación más natural de Rosa en Canarias.We are most grateful to botanists who provided essential dog-rose materials: Félix Manuel Medina, Toño Lerín (La Palma), Ángel Fernández and Ramón
Chinea “Sito” (La Gomera), Isa Nogales, C. Suarez & S. Cabrera (Gran Canaria), Cristina González Montelongo (TFC herbarium), Alfredo Reyes Betancort (ORT herbarium), Leopoldo Medina Domingo and Eva García Ibáñez (MA herbarium). In particular, we sincerely appreciate the persistent work of the plant artist Manuel Sánchez Villegas who performed the accurate scientific illustrations included in this paper. This research was supported by the project PIB 2022-13790 6NB-100, Ministerio de Ciencia, Innovación y Universidades
EL ESTADO DE CONSERVACIÓN DE LAS CÁRICES IBÉRICAS
No full textEL ESTADO DE CONSERVACIÓN DE LAS CÁRICES IBÉRICA
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