1,720,973 research outputs found
Rhodolith beds in a shallow-water carbonate reef lagoon on Moorea, French Polynesia
No full textPresent-day rhodolith beds are described from shallow water coral-reef related settings from Moorea, Tahiti, French Polynesia
Ephemeral masks in the ellipsoidal foraminifera Alveolinella and Borelis (Alveolinoidea): resilient solutions to stabilization in coral-reef settings
No full textIn modern Indo-Pacific coral-reef areas, the porcelaneous larger foraminifera Alveolinella quoyi and Borelis schlumbergeri, the only extant prolate ellipsoidal alveolinoids, live on sandy and coral-rubble substrates. Apertural features are functional elements of shell morphology; therefore, specimens were investigated to assess these characters. The primary apertures of these alveolinoid forms can be obstructed by two different masks (mineralized infraskeletal shell elements): sinusoidal reverse masks (pending from the upper border of the aperture) and upright (rising from the lower border). Alveolinella quoyi exhibits sinusoidal reverse masks, whereas B. schlumbergeri has upright masks. These masks consist of discrete groups of needle-shaped crystals. The reverse masks are part of the apertural rim, whereas the upright masks form from the basal layer. These ephemeral characters occur at the terminal stage of the formation of the apertural face and are resorbed after the calcification of the new chamber. These features, with no or very low fossilization potential, appear to reflect distinct functions during chamber growth. The extruding protoplasm from the reverse-mask and upright mask-bearing apertures enhances shell stabilization. In the poles, where the reverse masks and upright masks do not occur, the protoplasm likely enables motility
Boring bivalve traces in modern reef and deeper-water macroid and rhodolith beds
No full textMacroids and rhodoliths, made by encrusting acervulinid foraminifera and coralline algae, are widely recognized as bioengineers providing relatively stable microhabitats and increasing biodiversity for other species. Macroid and rhodolith beds occur in different depositional settings at various localities and bathymetries worldwide. Six case studies of macroid/rhodolith beds from 0 to 117 m water depth in the Pacific Ocean (northern Central Ryukyu Islands, French Polynesia), eastern Australia (Fraser Island, One Tree Reef, Lizard Island) and the Mediterranean Sea (southeastern Spain) show that nodules in the beds are perforated by small-sized boring bivalve traces (Gastrochanolites). On average, boring bivalve shells (gastrochaenids and mytilids) are more slender and smaller than those living inside shallow-water rocky substrates. In the Pacific, Gastrochaena cuneiformis, Gastrochaena sp., Leiosolenus malaccanus, L. mucronatus, L. spp. and Lithophaga/Leiosolenus sp., for the first time identified below 20 m water depth, occur as juvenile forms along with rare small-sized adults. In deep-water macroids and rhodoliths the boring bivalves are larger than the shallower counterparts in which growth of juveniles is probably restrained by higher overturn rates of host nodules. In general, most boring bivalves are juveniles that grew faster than the acervulinid foraminiferal and coralline red algal hosts and rarely reached the adult stage. As a consequence of phenotypic plasticity, small-sized adults with slow growth rates coexist with juveniles. Below wave base macroids and rhodoliths had the highest amounts of bioerosion, mainly produced by sponges and polychaete worms. These modern observations provide bases for paleobiological inferences in fossil occurrences
Ichnocoenoses in present-day macroid and rhodolith beds: controls and attributes for palaeoecological inferences
No full textRelations between landlords and tenants: modern macroid/rhodolith growth rate and boring bivalve activity
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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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