1,721,163 research outputs found
Ocean acidification and surface water carbonate production across the Paleocene–Eocene thermal maximum
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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
Records of coccolithophore calcification (coccolith length, thickness, and shape factor, estimated PIC:POC ratios) from three sites in the Atlantic Ocean over the past 29 million years compiled from literature
No full textThis dataset contains the data plotted in Figure 6 (panels a to d) of the review paper Coccoliths as Recorders of Paleoceanography and Paleoclimate over the Past 66 Million Years by Bolton & Stoll (2025, AREPS; doi:10.1146/annurev-earth-040623-103211). It contains previously published, in some cases updated, data on coccolith on Noelaerhabdaceae coccolith length, thickness, and shape factor (ks) and estimated PIC:POC ratios. The data provide insights into coccolith morphological evolution and degree of calcification, of interest for paleoceanographic and micropaleontological research. Data come from ODP Sites 925 and 926 and IODP Site U1406 sediment cores, drilled in the Atlantic Ocean, and are based on light microscope analyses
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
Growth rate and pCO2 reconstructions for the late Miocene Cooling
No full textThis table T6 contains pCO2 and algal growth rate simulations from Tanner et al. 2020 with their reported 1 simga confidence interval based on a full Monte Carlo Simulation (n=10'000). The calculations of simulation 1-7 are based on a multilinear regression model (Stoll et al. 2019) that used the isotopic fractionation (εp) during photosynthetic fixation of carbon, algal growth rate (μ), algal cell radius and the photosynthetic available radiation (PAR) to estimate past CO2. Proxy data are from the Ocean Drilling Program (ODP) core 1088, spanning the time interval of the late Miocene.
Simulation 8 follows the pCO2 calculations based on alkenones using the traditional, diffusive “b”-term approach (e.g. Zhang et al. 2013). Simulation 9 is a slight variation of this diffusive approach with coccolith size as a proxy for growth rate, according to Zhang et al. 2020.
The dataset provides a high-resolution trend over the late Miocene Cooling ranging from ~8 to 4.3 Ma. The different CO2-trends in this dataset are the main takeaway from the publication (Tanner et al. 2020) and help the reader understand the different thoughts and approaches that were taken in computing the published trend (based on simulation 1 and 6)
New age points of ODP Hole 177-1088B
No full textComposite core images for Ocean Drilling Program (ODP) Hole 1088B were generated by cutting individual core sections from core table photos (downloaded from JANUS: http://www-odp.tamu.edu/database/). Each section image was then compiled and scaled to the shipboard meters composite depth (mcd) using the Includes_Core_Table_Photos functions within Code for Ocean Drilling Data (CODD v1; www.codd-home.net; Wilkens et al. (2017)). To account for the single point lighting source used in core table photos, a lighting correction was also applied.
As shipboard color reflectance data was not collected at Site 1088, core color information (hue, saturation, lightness, red, green, blue) was extracted every mm from the composite core images using the CODD “CreateHoleCoreImageProfiles” function. The extracted lightness (L) showed the clearest variability and was chosen to approximate Lstar data. The top 4 cm of each section was excluded from the L profile to remove a lighting artefact at section ends. To account for core heterogeneity, the L data was then despiked using the CODD “Median_DeSpike” function (despiked data over 2 s.d. from the median within a 400 point/0.4 m window) and then smoothed using an 11-point binomial smoothing. All extracted data is provided in supplementary table 1.
The composite core images from Hole 1088B show clear evidence for core disturbance at the top of most cores (supplementary table 2). These intervals were excluded from the extracted lightness and shipboard magnetic susceptibility records. The shipboard magnetic susceptibility (MS) data was also despiked using the “Median_DeSpike” function (despiked data over 2 s.d. from the median within a 40 point/0.4 m window; supplementary tables 3).
An astrochronology for Hole 1088B was generated between 4.2 and 7.9Ma (38-90 mcd), using 24 minimal tie points between L maxima and ~110 kyr eccentricity maxima (Ecc; Laskar et al. (2004). These additional age points are provided in supplementary table 4
New Tie points, organic and inorganic data, growth rate and pCO2 reconstructions for the late Miocene Cooling of ODP Hole 177-1088B
No full textA pronounced late Miocene cooling (LMC) from 7 to 5.7 Ma has been documented in extratropical and tropical sea surface temperature records, but to date, available proxy evidence has not revealed a significant pCO2 decline over this event. Here, we provide a new, high resolution pCO2 proxy record over the late Miocene cooling based on alkenone carbon isotopic fractionation (εp) measured in sediments from the South Atlantic at ODP Site 1088. We apply a recent proxy calibration derived from a compilation of laboratory cultures, which more accurately reflects the proxy sensitivity to pCO2 changes during late Quaternary glacial-interglacial cycles, together with new micropaleontological proxies to reconstruct past variations in algal growth rate, an important secondary influence on the εp. Our resulting pCO2 record suggests a 2-3 fold decline over the late Miocene Cooling and confirms a strong coupling between climate and pCO2 through the late Miocene. Within this long-term trend are pCO2 variations on sub-myr timescales that may reflect 400kyr long-eccentricity cycles, in which pCO2 minima coincide with several orbital scale maxima in published high-resolution benthic 18O records. These may correspond to ephemeral glaciations, potentially in the Northern Hemisphere. Our temperature and planktonic 18O records from Site 1088 are consistent with substantial equatorward movement of Southern Ocean frontal systems during the LMC. This suggests that potential feedbacks between cooling, ocean circulation and deep ocean CO2 storage may warrant further investigation during the LMC
Extracted color reflectance profile data of ODP Hole 177-1088B
No full textComposite core images for Ocean Drilling Program (ODP) Hole 1088B were generated by cutting individual core sections from core table photos (downloaded from JANUS: http://www-odp.tamu.edu/database/). Each section image was then compiled and scaled to the shipboard meters composite depth (mcd) using the Includes_Core_Table_Photos functions within Code for Ocean Drilling Data (CODD v1; www.codd-home.net; Wilkens et al. (2017)). To account for the single point lighting source used in core table photos, a lighting correction was also applied.
As shipboard color reflectance data was not collected at Site 1088, core color information (hue, saturation, lightness, red, green, blue) was extracted every mm from the composite core images using the CODD “CreateHoleCoreImageProfiles” function. The extracted lightness (L) showed the clearest variability and was chosen to approximate Lstar data. The top 4 cm of each section was excluded from the L profile to remove a lighting artefact at section ends. To account for core heterogeneity, the L data was then despiked using the CODD “Median_DeSpike” function (despiked data over 2 s.d. from the median within a 400 point/0.4 m window) and then smoothed using an 11-point binomial smoothing. All extracted data is provided in supplementary table 1.
The composite core images from Hole 1088B show clear evidence for core disturbance at the top of most cores (supplementary table 2). These intervals were excluded from the extracted lightness and shipboard magnetic susceptibility records. The shipboard magnetic susceptibility (MS) data was also despiked using the “Median_DeSpike” function (despiked data over 2 s.d. from the median within a 40 point/0.4 m window; supplementary tables 3).
An astrochronology for Hole 1088B was generated between 4.2 and 7.9Ma (38-90 mcd), using 24 minimal tie points between L maxima and ~110 kyr eccentricity maxima (Ecc; Laskar et al. (2004). These additional age points are provided in supplementary table 4
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