1,720,965 research outputs found
Chemical data of soil density fractions from Gaburumata mangrove, Ishigaki Island, Japan
No full textThe study area, located along the Gaburumata River on Ishigaki Island, Okinawa Prefecture, Japan (24°30'18.5N, 124°14'52.2E), comprises a mangrove forest covering approximately 1.5 ha around the river estuary. The vegetation is dominated by Bruguiera gymnorrhiza. Transects were established at three points (upstream, midstream, downstream) running from north to south. Sampling was conducted in June 2022 at five depths: 0-10, 10-20, 20-40, 40-70, and 70-100 cm, respectively, using a stainless-steel soil auger. Samples were collected at ten locations along each transect at approximately equal intervals. Corresponding depth sections were composited to create one composite sample per depth per transect, which was then stored in plastic bags under cool, dark conditions and transported to the laboratory. Composited samples were frozen and subjected to vacuum freeze-drying for seven days. Subsequently, the freeze-dried soil was gently sieved through a 2 mm mesh sieve. Density fractionation was performed using an aqueous solution of sodium polytungstate (SPT-0, TC-Tungsten Compounds, Germany; SPT) with a density of 1.6 g cm³ with the optimized protocol described in the accompanying paper. After density fractionation, each density fraction was freeze-dried, ground to powder, and measured for elemental analysis, stable carbon and radiocarbon analysis, and extractable metals analysis (Al, Fe, Ca, Mg)
Global database of Andisols and associated meta-data from literature
No full textWe synthesized a global Andisol database to improve estimates of global SOC stock and identify the key factors influencing spatial variation in SOC content in Andisols. Major samples (260 pedons, 1453 horizons) were obtained from the Tohoku University World Andosol Database (TUWAD) (Shoji et al., 1996; doi:10.1097/00010694-199609000-00005). All data in the TUWAD were manually checked by referring to the original publications, and any typographical errors, missing data in calculations, or incorrect placements of zeros where they should have been blanks, were corrected. Additional data were collected through a literature search in English on Web of Science. Our literature search was conducted for papers published from 1994 onwards post-compilation of TUWAD and was completed in November 2021. We excluded O and R horizons if they were reported (also from TUWAD), as we focused on mineral soil horizons. In total, we gathered 2854 samples from 574 pedons across 34 countries including data from TUWAD. Climatic variables included mean annual temperature (MAT) and mean annual precipitation minus potential evapotranspiration (MAP-PET), estimated by TerraClimate (data between 1958 and 2019, ~5 km resolution) (Abatzoglou et al., 2018; doi:10.1038/sdata.2017.191). Net primary production (NPP) data was estimated by MODIS/Terra Net Primary Production (MOD17A3HGF v006, data between 2000 and 2021, 500 m resolution) (Running & Zhao, 2021; doi:10.5067/modis/mod17a3hgf.061) and vegetation type was by Copernicus Global Land Cover Layers (CGLS-LC100 Collection 3, data between 2015 and 2019, 100 m resolution) (Buchhorn et al., 2020; doi:10.3390/rs12061044). For more specifications, please see the accompanying paper
Molecular formulae assignments and compound category classifications from the 58th Japanese Antarctic Research Expedition
No full textThe sampling campaign was conducted during the austral summer between December 2016 and February 2017 as a part of the 58th Japanese Antarctic Research Expedition. On Sôya Coast (Lützow-Holm Bay, East Dronning Maud Land, East Antarctica), there are hundreds of lakes with variable water chemistry which were formed during the last 7,000 years under the glacier retreat and iso-static uplifts that occurred after the Last Glacial Maximum. Water samples were collected either at the center of the lakes or at the shore into 550-mL PET bottles after rinsing more than three times with the collected water. Within a few hours after sampling, samples were filtered through pre-combusted (450dc, >3 h) glass-fiber filters (nominal pore size 0.3mm, GF-75, Advantec, Tokyo, Japan) into pre-combusted glass bottles (see doi:10.1016/J.WATRES.2019.114901). The filtered samples were immediately spiked with sodium azide (final concentration of 0.02%) for preservation, stored dark at 5dc, and shipped back to Japan. DOM was extracted and desalted prior to FT-ICR MS analysis following an established method using cartridges filled with a styrene-divinylbenzene copolymer (Agilent Bond Elut PPL, 100 mg). Depending on the DOC concentration, the volume used for extraction was adjusted such that 4 µmol C was applied to each cartridge. We performed a mass spectrometric analysis of DOM extracts via FT-ICR MS on a 15 Tesla solariX XR Fourier-transform ion cyclotron resonance mass spectrometer (Bruker Daltonik GmbH, Bremen, Germany). The system was equipped with an electrospray ionization source (ESI, Bruker Apollo II) applied in negative ionization mode. Methanol extracts were mixed with ultrapure water (50:50 v/v) for FT-ICR MS analysis and diluted to a final DOC concentration of 2.5 mg C/L. 200 single scans with an ion accumulation time of 0.1 s were recorded over a mass range of m/z 92 to 2,000 Da and added to one spectrum. Data processing, molecular formulae assignments, and compound category classifications were done with the software package ICBM-OCEAN
Dissolved organic matter composition in Antarctic streams (Sôya Coast, Lützow-Holm Bay, East Dronning Maud Land, East Antarctica) derived from FT-ICR-MS analyses during JARE58
No full textThe sampling campaign was conducted during the austral summer in January 2017 as a part of the 58th Japanese Antarctic Research Expedition. There are several ice-free areas on Sôya Coast with hundreds of lakes and several streams, which were formed during the last 7,000 years under the glacier retreat and iso-static uplifts that occurred after the Last Glacial Maximum. The Langhovde ice-free area is located ~25 km away from Japan's Syowa Station. The Yukidori and Yatsude Valleys in Langhovde run from the edge of the continental ice sheet to Lutzow-Holm Bay. At each stream of the valleys, water samples were directly collected into 550-mL volume polyethylene terephthalate bottles after rinsing more than three times with the collected water. The collected waters were filtered in a field laboratory within a few hours after sampling. Samples were filtered through pre-combusted (450dc, >3 h) glass-fiber filters (nominal pore size 0.3mm, GF-75, Advantec, Tokyo, Japan) into pre-combusted glass bottles (see doi:10.1016/J.WATRES.2019.114901). The filtered samples were immediately spiked with sodium azide (final concentration of 0.02%) for preservation, stored dark at 5dc, and shipped back to Japan. DOM was extracted and desalted prior to FT-ICR MS analysis following an established method using cartridges filled with a styrene-divinylbenzene copolymer (Agilent Bond Elut PPL, 100 mg). Depending on the DOC concentration, the volume used for extraction was adjusted such that 4 µmol C was applied to each cartridge. We performed a mass spectrometric analysis of DOM extracts via FT-ICR MS on a 15 Tesla solariX XR Fourier-transform ion cyclotron resonance mass spectrometer (Bruker Daltonik GmbH, Bremen, Germany). The system was equipped with an electrospray ionization source (ESI, Bruker Apollo II) applied in negative ionization mode. Methanol extracts were mixed with ultrapure water (50:50 v/v) for FT-ICR MS analysis and diluted to a final DOC concentration of 2.5 mg C/L. 200 single scans with an ion accumulation time of 0.1 s were recorded over a mass range of m/z 92 to 2,000 Da and added to one spectrum. Data processing, molecular formulae assignments, and compound category classifications were done with the software package ICBM-OCEAN
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
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