1,721,038 research outputs found
An annotated catalog of fossil and subfossil Lepidoptera (Insecta: Holometabola) of the world 3286
No full textSohn, Jae-Cheon, Labandeira, Conrad, Davis, Donald, Mitter, Charles (2012): An annotated catalog of fossil and subfossil Lepidoptera (Insecta: Holometabola) of the world 3286. Zootaxa 3286 (1): 1-132, DOI: 10.11646/zootaxa.3286.1.1, URL: https://biotaxa.org/Zootaxa/article/view/zootaxa.3286.1.
A leafcutter bee trace fossil from the middle eocene of patagonia, Argentina, and a review of Megachilid (Hymenoptera) ichnology
Full text linkThe ichnospecies Phagophytichnus pseudocircus isp. nov. is described to include trace fossils characterized by leaf-margin excisions showing eccentricity values of 0.35-0.65 and more than 270 degrees of an arc, a non cuspate margin and vein stringers or necrotic flaps of tissue along the margin. A method for determining ellipse eccentricity was performed on leaf discs obtained from the nests of the modern leafcutter bee Megachile rotundata (Hymenoptera: Megachilidae), which provided objectively obtained values comparable to the trace fossil from the middle Eocene of Argentina and other world-wide ichnological records, historically and subjectively considered to be 'circular' trace fossils and attributed to leafcutter bees. The material described herein represents the first evidence for fossil Megachilidae from the Southern Hemisphere.Fil: Sarzetti, Laura Cristina. Museo Paleontológico Egidio Feruglio; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Labandeira, Conrad C.. National Museum of Natural History; Estados Unidos. University of Maryland; Estados UnidosFil: Genise, Jorge Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Museo Paleontológico Egidio Feruglio; Argentin
Silurian to Triassic plant and hexapod clades and their associations: new data, a review, and interpretations
No full textA preliminary evaluation of hexapod herbivore damage from selected compression and permineralized biotas from the 220 million-year Late Silurian to Late Triassic interval has revealed many previously unknown patterns of hexapod herbivore use of vascular plants as well as detritivore and predator associations. Data was collected from 48 distinctive hexapod herbivore damage types (DTs) from 21 mostly compression biotas, but with special emphasis on the Rhynie Chert (Early Devonian, ~ 408 Ma), Calhoun Coal (Late Pennsylvanian, ~ 303 Ma) and Molteno Formation (Late Triassic, ~ 226 Ma). These data indicate a two-phase herbivore colonization of land; later expansion of hexapod functional feeding groups (FFGs) initially in the Late Pennsylvanian wetland environments of equatorial Euramerica, and subsequently in Early Permian fluvial systems in the rest of Euramerica, Gondwana, and Cathaysia; the devastating end-Permian extinction; and subsequent rebound of those same FFGs during the ensuing Triassic. Modern-aspect herbivore, detritivore, and predator FFGs are present in Late Pennsylvanian canopied forests, and the full spectrum of all terrestrial FFGs are in place during the Late Triassic. Freshwater FFGs are delayed when compared to the terrestrial record, originating during the Permian, experiencing expansion during the Triassic, and reaching modern levels of all major trophic types during the Late Jurassic. A major conclusion is the omnipresence of convergence in FFGs throughout this interval and the spatiotemporally changing and ephemeral nature of plant hosts and their hexapod herbivore tax
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
Diverse plant-insect associations from the latest Cretaceous and early Paleocene of Patagonia, Argentina
No full textLittle is known about the recovery of terrestrial ecosystems after the end-Cretaceous extinction outside of the Western Interiorof North America, relatively close to the 66 Ma bolide impact crater in Chicxulub, Mexico. A previous report showed that in Patagonia, Argentina,insect damage on fossil leaves decreased from the latest Cretaceous to early Paleocene but recovered to pre-extinction levelswithin ca. four million years. Here, we present the first detailed study of these Patagonian plant-insect associations, key componentsof terrestrial food webs, during the latest Cretaceous and three time slices from the early Paleocene recovery. The lithologic units studiedare the uppermost Cretaceous portion of the Lefipán Formation and the Danian Salamanca and Peñas Coloradas formations in Chubut,Argentina. Seven functional feeding groups are present throughout: hole feeding, margin feeding, skeletonization, surface feeding, piercingand sucking, mining, and galling. Fifty damage types (DTs) were present at Maastrichtian localities, and 39?48 were found at Danian localities.Plant-insect associations that apparently went locally extinct at the end of the Cretaceous include several gall, mine, and piercingand-sucking DTs. Based on our preliminary leaf morphotypes, host plants did not provide refuge for specialized insect herbivores across theK/Pg boundary. Despite a decrease in insect damage diversity after the bolide impact, Danian floras hosted a rich array of DTs, including specializeddamage such as mines and galls. Many of these early Paleocene DTs were not found in the terminal Cretaceous, providing evidencefor a rapid recovery of plant-insect associations regionally.Fil: Donovan, Michael P.. State University of Pennsylvania; Estados UnidosFil: Iglesias, Ari. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of Maryland; Estados UnidosFil: Wilf, Peter. State University of Pennsylvania; Estados UnidosFil: Labandeira, Conrad. Capital Normal University; China. University of Maryland; Estados UnidosFil: Cúneo, Néstor Rubén. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Museo Paleontológico Egidio Feruglio; Argentin
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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