1,721,020 research outputs found
A 2100 year BP record of the Pacific Decadal Oscillation, El Niño Southern Oscillation and Quasi-Biennial Oscillation in marine production and fluvial input from Saanich Inlet, British Columbia
No full textExceptional varved sediments of 2100 years BP recovered from Saanich Inlet have been analysed using high-resolution scanning electron microscopy and spectral analysis techniques. Each varve may contain up to 22 well defined individual laminae which can be attributed to seasonal-scale processes. Sediment flux comprises alternating diatom ooze/diatomaceous mud deposited during spring through autumn and a silty-clay deposited during winter. The latter may be sporadically punctuated by clay-rich laminae. Identification of some 2000 individual consecutive laminae, based on fabric and diatom assemblage, has allowed the construction of time series data for spectral analysis. Laminae types analysed include: early spring Thalassiosira spp., late spring/early summer Skeletonema costatum, multiple summer/autumn Chaetoceros spp. diatom oozes and sporadically present clay-rich winter flood deposits. Sub-decadal periods have been identified and linked to the Quasi-Biennial Oscillation (QBO) and El Niño Southern Oscillation (ENSO), and decadal periods to the Pacific Decadal Oscillation (PDO). Comparison of spectral analysis results with modern analogues suggests associations may exist between: early spring Thalassiosira spp. laminae and stronger La Niña events; late spring/early summer S. costatum laminae and El Niño events; summer/autumn Chaetoceros spp. multiple laminae and negative Pacific Northwest Index (PNI) regimes; and sporadically present winter clay-rich laminae and PNI-regimes. The average period for an ENSO cycle was 3.6 years, QBO 2.5 years and PDO 14.8 years. Spectral analysis of the more recent PNI record shows similar significant periods of 13.2, 3.7 and 2.6 years. Multi-decadal periods recorded include: 42.2 and 31.3 years, which might suggest multiples of PDO
Palaeo-flux records from electron microscope studies of Holocene laminated sediments, Saanich Inlet, British Columbia
No full textHolocene varved sediments recovered from Saanich Inlet, ODP Leg 169S, have been analysed using high-resolution scanning electron microscope techniques. The individual centimetre-scale varves form couplets, comprising diatom ooze/diatomaceous mud deposited during spring to autumn and silty clay deposited during winter. Each individual varve may contain up to 19 laminae, recording sub-seasonal to seasonal-scale processes. These intra-annual laminae contain a range of components, including pelagic faecal pellets and aggregates of diatomaceous material. The combination of these individual components in varying proportions with a heterogeneous sediment, leads to a range of laminae fabrics. These include intact monospecific Skeletonema costatum and Thalassiosira pacifica diatom oozes and highly fragmented, aggregate- and faecal pellet-dominated diatom oozes which are typically Chaetoceros spp.-dominated. Additional laminae fabrics include diatomaceous mud, stringer-type diatomaceous mud which contains discrete diatom aggregates, homogeneous and pelleted silty clay. The varved diatom succession typically commences in early spring with Thalassiosira spp./Chaetoceros spp., followed by Chaetoceros spp. in late spring. During late spring/early summer blooms of S. costatum may be recorded, and summer to autumn production is characterised by one to several Chaetoceros spp.-dominated blooms. Inter-annual variability in diatom flux typically comprises the presence/absence of Thalassiosira spp. and S. costatum. In addition, resting spores of Chaetoceros spp., Thalassiosira nordenskioeldii and Leptocylindricus danicus are intermittently recorded. There is a major change in varve thickness from thinner varves prior to approximately 2100 yr BP to thicker varves after this date, which is attributed to increased terrigenous input throughout the varve. The identification of laminae fabrics, diatom successions and a unique massive interval has enabled an inter-site correlation between sites 1033B and 1034B
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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