1,721,306 research outputs found
Sea surface temperature, Hemisdiscus karstenii and Fragilariopsis kerguelensis biometry of sediment core DCR-1PC, southwest Indian sector of the Southern Ocean
No full textThis data publication contains sea-surface temperatures and diatom abundances and biometry in sediment core DCR-1PC from the southwestern Indian sector of the Southern Ocean over the last 350,000 years. Core DRC1-PC was retrieved during the oceanographic expedition Hakuho-maru KH-10-7 during the austral summer 2010-2011. Diatom census counts and diatom biometry were performed in 2018-2019 to investigate the potential impact of climate degradation on Hemisdicus karstenii disappearance at ~190 ka.
Included are relative abundances (RA in % of the total diatom assemblages) and absolute abundances (AA in millions of valve per gram of dry sediment) of Hemidiscus karstenii (Hk) and Fragilariopsis kerguelensis (Fk). Summer sea-surface temperatures (January to March) were estimated by applying the Modern Analog Technique (MAT) to fossil diatom assemblages. Hk and Fk biometry versus depth and age are also included. For each depth, mean length results from measurements of 100 different and complete valves of both Hk and Fk on which within-sample standard deviations were calculated
Diatom distribution in IODP Hole 318-U1357B
No full textThis data publication contains the relative abundances of the Fragilariopsis curta group (F. curta and F cylindrus) and the Thalassiosira antarctica group (resting spores and vegetative cells of T. antarctica cold variety) versus depth (in meters below sea-floor) and age (in years Common Era) in core IODP U1357B. Core IODP U1357B was retrieved in the Dumont d'Urville Trough off Adélie Land, East Antarctica, during the IODP expedition 318 "Wilkes Land Glacial History" conducted on board the R.V. Joides Resolution during the austral summer 2010. The relative abundances of the F. curta group and the T. antarctica group were produced to document changes in spring and autumn sea-ice conditions, respectively, off Adélie Land at decadal timescale over the last 2000 years
Diatom-based sea-surface temperatures over the last 40 kyrs in sediment core MD11-3353 off Kerguelen Island, Southern Ocean
No full textDiatom census counts were used to quantitatively estimate summer sea-surface temperatures (SST) over the last 40,000 years in core MD11-3353, collected in 2011 on board the R.V. Marion Dusfresne west of Kerguelen Island, Southern Ocean. The transfer function used to reconstruct summer (Janunary to March) SST is the Modern Analog Technique that here uses 249 surface sediment samples (modern analogs), the relative abundances of 32 diatom species and the chord distance to select the five most similar modern analogs (Crosta et al., 2020). This method yields a root mean square error of prediction of ~1 °C. The core chronology is detailed in Thöle et al. (2019)
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
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