1,721,161 research outputs found
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
Carbon isotopic equilibrium of the surface waters as a proxy for climate change through the last glacial/interglacial cycle in the Southwest Pacific
No full textCarbon-13 is a relatively understudied geochemical property in the world ocean. The Southwest Pacific, in particular, is devoid of δ¹³C data. This thesis therefore has two main objectives: to create a model to describe the modern distribution of δ¹³C around New Zealand (30-70°S, 140°E-150°W), and to describe changes in δ¹³C in a latitudinal transect of cores to the east and south of New Zealand. A model using multiple linear regression was created by comparing δ¹³C with potential temperature, salinity, density, and oxygen data. This model matches well with ship board δ¹³C measurements taken throughout the region. The resulting models were then compared to core top data to determine how well modern δ¹³C values compare to the Holocene, pre-industrial values. A new model, based on previous pre-industrial models, was created at much higher resolution to recreate the pre-industrial δ¹³C distribution. Core top values were found to be intermediate between Holocene and modern values. Down core δ¹³C data was split into six regions based on oceanographic conditions to determine what caused and how δ¹³C change occurred in the past. Data was run through 1000 iterations of a Monte Carlo simulation to determine a robust δ¹³C curve back through time. The biologic pump was found to dominate the δ¹³C levels in the region through iron fertilization and increased productivity in the polar zone. The LGM and deglacial δ¹³C values reflect greater influence on δ¹³Catm, suggesting that an increase in upwelling along the Antarctic coast and a possible strengthening of the westerly wind belt caused changes in ocean circulation throughout the region. The ACR and Early Holocene periods show good correlation with atmospheric CO₂ records, suggesting increasing temperatures may have increased productivity. The remainder of the Holocene to the present is mainly influenced by δ¹³Catm, suggesting relatively stable conditions in ocean and atmosphere
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
Millennial Scale Events from Marine Sediment Cores in the SW Pacific During Marine Isotope Stage 3
No full textMarine Isotope Stage 3 (MIS3) is an important period in the Earth's climate history as it contains a series of millennial scale events. These can be reconstructed to help interpret the response of the Earth’s ocean/climate system to rapid climate events and this may have important connotations for the Earth's system response under anthropogenically induced climate change. During MIS3, millennial scale events in the Antarctic ice core record occur out of phase with millennial scale events in the Greenland ice core record. Antarctic millennial scale events are defined peaks in δ¹⁸O and are known as Antarctic Isotope Maxima (AIM) events. These events have been recorded in high-resolution marine sediment records in the Southern Ocean, but there is sparse literature at a high enough resolution to extract the millennial scale signal from marine cores in the SW Pacific during MIS3.
This study developed high-resolution marine sediment records in the New Zealand region from cores TAN1106-28, collected in the Solander Trough region south of New Zealand, and MD97-2121, collected off the east coast of Hawkes Bay, to reconstruct millennial scale variability in the SW Pacific during MIS3. Productivity and terrestrial mass accumulation rates (MAR) were combined with stable isotopes and ITRAX XRF analysis to reconstruct ocean/climate variability during MIS3 and identify AIM events. ITRAX XRF produced high-resolution (1 mm scale) elemental proxy data which showed a high correlation coefficient between ITRAX Ca, and CaCO3 % calculated using the vacuum gasometic procedure. This suggested that ITRAX XRF accurately represented elemental variations in these marine sediment cores, and that it may be a valuable tool for high-resolution climate reconstruction. ITRAX XRF was also used to identify the Rotoehu, Tahuna and Kawakawa cryptotephra in MD97-2121. However, this analysis was only moderately successful as ITRAX elemental proxies showed multiple cryptotephra events. Samples which contained these events then had to be classified as a cryptotephra deposit using a binocular microscope, and identified as a specific tephra eruption through electron microprobe analysis.
MIS 3 reconstructions for TAN1106-28 show AIM events in both productivity fluctuations and terrestrial sedimentary input. Productivity at the site of TAN1106-28 increased during AIM events and this is consistent with findings from marine sediment cores throughout the Southern Ocean. In the New Zealand region increased productivity during AIM events was inferred to be a response to the increased availability of light or warmer sea surface temperatures, as iron decreased during AIM events, suggesting productivity was not driven by iron fertilisation. The decrease in iron and other terrigenous proxies likely reflects increased glacial erosion during the stadial phase of Antarctic millennial scale events as recorded in the onshore record during the Antarctic Cold Reversal. Overriding these millennial scale fluctuations was an increase in terrigenous accumulation heading into the MIS 2 glaciation.
Like TAN1106-28, sediment accumulation increased at the site of MD97-2121 heading into the MIS 2 glacial. This suggests that eustatic sea level variations have a strong control on terrestrial accumulation in the wider New Zealand region. Unlike TAN1106-28 however, there is little evidence for AIM events in MD97-2121 to the north of the front, strongly suggests the STF acts as a boundary to the AIM signal, restricting northward movement of the signal in the Southern Hemisphere mid latitudes
Glacial-interglacial productivity in the Polar Frontal Zone, southwest Pacific Ocean
No full textThe Southern Ocean has a central role in regulating global climate change. Research has shown evidence of changes in biological productivity are coincident with increased iron deposition and rising atmospheric CO2 concentrations. The current data suggests these processes occur homogenously throughout the Southern Ocean, where research largely focuses on changes in biogenic silica as a proxy for upwelling and enhanced opal production. The role of calcium carbonate productivity, however, is rarely discussed, or is referred to in terms of preservation changes associated with shoaling and deepening of the lysocline. This assumption ignores potentially important effects of carbonate productivity and inter-basin complexities on ocean-atmosphere CO2 exchange.
Two gravity cores (TAN1302-96 and TAN1302-97) collected from the southwest Pacific Polar Frontal Zone (PFZ) provide more insight into productivity changes and inter-basin differences across glacial-interglacial timescales. Detailed geochemical analysis, together with δ18O stratigraphy and 14C chronology, were used to reconstruct glacial-interglacial changes in terrigenous input and paleoproductivity in the PFZ. Sedimentological and biological analyses provide additional information to support the geochemical
observations.
This study highlights two distinct productivity modes (i.e. biogenic silica and calcium carbonate) that vary over glacial-interglacial timescales and with respect to the position of the Polar Front (PF). Key findings include; 1) a systematic series of key biological changes are repeated during glacial Terminations I (TI) and II (TII), the order of which depends on the position relative to the PF; 2) calcium carbonate productivity dominates the early part of the Termination north of the PF, whereas the production of biogenic silica dominates the early Termination south of the PF; 3) following TI and TII, calcium carbonate leads productivity in the early interglacials (i.e. MIS 5e and the Holocene), followed by the production of biogenic silica during the late interglacials, concurrent with declining atmospheric CO2 concentrations
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
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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