1,720,979 research outputs found
Monogenic volcanoes of Patagonian back-arc province, southern Argentina
No full textIn the southern Andes back-arc, behind the South Volcanic Zone (SVZ) and Austral Volcanic Zone (AVZ), hundreds of monogenic basaltic volcanoes took place, forming numerous cinder cones and lava flows.Fil: Motoki, Akihisa. Universidade do Estado de Rio do Janeiro; BrasilFil: Orihashi, Yuji. University of Tokyo; JapónFil: Hirata, Daiji. Kanagawa Prefecture Museum of Natural History; JapónFil: Haller, Miguel Jorge F.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Hosono, Takahiro. Tsukuba University; JapónFil: Dias Cario, Felipe. Universidade Federal Fluminense; BrasilFil: Schilling, Manuel. Universidad de Chile; ChileFil: Anma, Ryo. Tsukuba University; Japó
Bending-Related Topographic Structures of the Subducting Plate in the Northwestern Pacific Ocean
No full textElongated topographic structures associated with bending of the subducting oceanic plate along the western Kuril, Japan and northern Izu-Ogasawara trenches, were investigated using available multibeam bathymetric data. Magnetic anomaly lineations were also reidentified using available geomagnetic data to reveal controlling factors for strikes of bending-related topographic structures. The new bathymetric map demonstrates that most of bending-related topographic structures exist in the oceanward trench slopes deeper than 5,600 m. The map reveals that bending-related topographic structures are developed parallel to the trench axis or inherited seafloor spreading fabrics. Detailed identification of magnetic anomalies reveals curved lineations and discontinuity of lineations associated with propagation ridges. A trough with elongated escarpments associated with the propagating ridge in mid-Cretaceous Quiet Period was discovered near the trench-trench-trench triple junction. Comparison between the detailed bathymetric and magnetic anomaly lineation maps elucidates that abyssal hill fabrics were reactivated where the angle between abyssal hill fabrics and trench axis is less than about 30°. The topographic expression of bending-related structures are classified into two types according to whether new faults develop parallel to the trench axis or inherited seafloor spreading fabrics reactivate
Holocene fluvial and anthropogenic processes in the region of Uruk in southern Mesopotamia
Get PDFFor decades, it has been unclear as to how the world's first cities, in southern Mesopotamia, not only arose in a fluvial environment but also how this environment changed. This paper seeks to understand the long-term fluvial history of the region around Uruk, a major early city, in relation to water-human interactions. This paper applies geomorphological, historical and archaeological approaches and reveals that the Uruk region in southern Mesopotamia had been under the influence of freshwater fluvial environment since the early Holocene. It further demonstrates how canals and long-term human activities since the mid Holocene have been superimposed on the natural river channel patterns. Fieldwork has been conducted to ground-truth features identified applying remote sensing techniques. Five sediment cores were analysed to elucidate palaeoenvironmental changes. Radiocarbon ages for organic samples suggest that the oldest sediment layers, at a depth of 12.5 m, are from the Early Holocene, while results from diatom analyses imply that the whole sediment column was deposited in a freshwater environment. Intensive networks of palaeochannels and archaeological sites within the study area have been reconstructed and these networks have been divided into four different time intervals based on changes in channel courses. The first is from the early 4th to the late 1st millennium BCE; the second is from the late 1st millennium BCE to the middle 2nd millennium CE; the third lasted from after the Islamic period until the 1980s; the fourth is from the 1980s until the present. Key results include evidence for freshwater environments and favourable settlement conditions had already formed by the 8th millennium BCE. The favourable settlement environment resulted in stable (long-lived) canals between the 4th millennium BCE and 1st millennium CE. A significant settlement and irrigation expansion occurred in the early 1st millennium CE. Major abandonment ensued in the late 1st millennium CE and lasted until the mid 2nd millennium CE
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
- …
