1,720,969 research outputs found
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
Spårämnesdata (Ba/Ca) från bottenlevande foraminiferer, provtagna i ytsediment från Gullmarsfjorden, Sverige.
No full textDataset of Ba/Ca in Bulimina marginata and Nonionellina labradorica (CTG-labelled) acquired by Laser-Ablation Inductively Coupled Mass Spectrometry (LA ICP MS; Department of Geology, Lund University, Lund, Sweden). Comprises data of the three most-recently formed chambers (n, n-1 and n-2), as well as the proloculus area (p; B. marginata only). The specimens were collected from core-top samples of two sites in Gullmar Fjord, Swedish West coast, Sweden over a temporal gradient spanning the year 2018 and 2019. The data set is part of a study exploring the response of foraminiferal Ba/Ca to contrasting hydroclimatic conditions. A publication including this data is currently ongoing. Please contact the main author for further details ([email protected]). Gullmar Fjord was sampled in September 2018, February 2019 and June 2019 (R/V Oscar von Sydow and R/V Skagerak, respectively) at GF 117 (115–117 m; 58º19.695’N, 11º33.147’E) and GF 71 (69–71 m; 58º17.116’N, 11º30.546’E). Sediment cores were recovered with a GEMAX® twin-barrel corer (modified Gemini corer, 9 cm diameter, from Oy Kart AB, Finland). The top 1 cm of the cores were collected and CTG-labelled to identify living foraminifera. Bulimina marginata and Nonionellina labradorica specimens were selected and bleached (NaOCl 5%). Trace element concentrations of test walls were analysed using a Bruker Aurora Elite (quadrupole) ICP‐MS and a 193 nm Cetac Analyte G2 excimer laser installed with a two volume HelEx2 sample cell (Dept. of Geology, Lund University, Lund, Sweden). U.S. National Institute of Standards and Technology SRM NIST610 was used as external calibration material with GeoReM (Geological and Environmental Reference Materials; Jochum et al., 2005) composition values (via http://georem.mpch-mainz.gwdg.de).Dataset över Ba/Ca från de tre senaste bildade kamrarna (n, n-1, n-2) i skal av Bulimina marginata och Nonionellina labradorica, analyserades genom laserspektroskopi (LA ICP MS; geologiska institutionen, Lunds universitet, Lund, Sverige). I skal av Bulimina marginata analyserades även de första kamrarna (p). Individer provtogs från ytsediment från två stationer i Gullmarsfjorden under 2018 och 2019. Datasetet är en del av en studie för att undersöka hur Ba/Ca kvoten i foraminiferers skal ändras med ändrat hydroklimatiskt läge. En publikation där detta dataset ingår är inskickad till granskning. Kontakta huvudförfattaren för fler detaljer. ([email protected]). För att använda datasetet måste källa anges. Gullmarsfjorden provtogs i september 2018, februari 2019 och juni 2019 (R/V Oscar von Sydow och R/V Skagerak), GF 117 (115–117 m vattendjup; 58º19.695’N, 11º33.147’Ö) och GF 71 (69–71 m vattendjup; 58º17.116’N, 11º30.546’Ö). Sedimenten provtogs med en GEMAX® twin-barrel corer (modifierad Gemini corer, 9 cm diameter, från Oy Kart AB, Finland). Sedimentprover togs från ytan av sedimentkärnorna (1 cm) och CTG tillsattes för att särskilja mellan levande och döda foraminiferer. Utvalda (nu döda) individer blev blekta (NaOCl 5%) innan analyserna. Koncentrationerna av spårelementinnehållet i skalväggen analyserades genom laserspektroskopi (LA ICP MS; geologiska institutionen, Lunds universitet, Lund, Sverige)
Spårämnesdata (Mn/Ca) från bottenlevande foraminiferer, provtagna i ytsediment från Gullmarsfjorden, Sverige
No full textDataset of Mn/Ca in Bulimina marginata and Nonionellina labradorica (CTG-labelled) acquired by Laser-Ablation Inductively Coupled Mass Spectrometry (LA-ICP-MS). Comprises data of the three most-recently formed chambers (n, n-1 and n-2), as well as the proloculus area (p; B. marginata only). The specimens were collected from core-top samples of two sites in the fjord Gullmarn on the west coast of Sweden over a temporal gradient spanning the years 2018 and 2019. The data set is part of a study exploring the response of foraminiferal Mn/Ca to low-oxygen bottom-water conditions. Sediment from the fjord Gullmarn was sampled in September 2018, February 2019 and June 2019 (R/V Oscar von Sydow and R/V Skagerak, respectively) at two sites: GF 117 (115–117 m water depth; 58º19.695’N, 11º33.147’E) and GF 71 (69–71 m water depth; 58º17.116’N, 11º30.546’E). Sediment cores were recovered with a GEMAX® twin-barrel corer (modified Gemini corer, 9 cm diameter, from Oy Kart AB, Finland). The top 0-1 and 1-2 cm of the cores were collected and CTG-labelled to identify living foraminifera. Bulimina marginata and Nonionellina labradorica specimens were selected and bleached (NaOCl 5%). Trace element concentrations of test walls were analysed using a Bruker Aurora Elite (quadrupole) ICP‐MS and a 193 nm Cetac Analyte G2 excimer laser installed with a two volume HelEx2 sample cell (Dept. of Geology, Lund University, Lund, Sweden). U.S. National Institute of Standards and Technology SRM NIST610 was used as external calibration material with GeoReM (Geological and Environmental Reference Materials; Jochum et al., 2005) composition values (via http://georem.mpch-mainz.gwdg.de). Please contact the main author for further details.Dataset över Mn/Ca i skal av Bulimina marginata och Nonionellina labradorica (CTG-märkta) analyserades genom laserspektroskopi (LA-ICP-MS). Mn/Ca mättes i de tre senast bildade kamrarna (n, n-1, n-2), och i skal av Bulimina marginata analyserades även de första kamrarna, så kallade 'proloculus' (p). Exemplaren provtogs från ytsediment från två platser i Gullmarsfjorden under 2018 och 2019. Datasetet är en del av en studie som undersöker hur Mn/Ca kvoten i foraminiferers skal påverkas av förändrad syrehalt i bottenvatten. Sediment från Gullmarsfjorden provtogs i september 2018, februari 2019 och juni 2019 (R/V Oscar von Sydow respektive R/V Skagerak) på två platser: GF 117 (115–117 m vattendjup; 58º19.695’N, 11º33.147’E) och GF 71 (69–71 m vattendjup; 58º17.116’N, 11º30.546’E). Proven togs med en GEMAX® twin-barrel corer (modifierad Gemini corer, 9 cm diameter, från Oy Kart AB, Finland). Sedimentprov togs från ytan av sedimentkärnorna (0-1 cm och 1-2 cm) och CTG tillsattes för att särskilja mellan levande och döda foraminiferer. Utvalda (nu döda) exemplar blektes (NaOCl 5%) innan analyserna. Koncentrationerna av spårelementinnehållet i skalväggen analyserades med laserspektroskopi (LA-ICP-MS; geologiska institutionen, Lunds universitet, Lund, Sverige). För ytterligare information, se den engelska katalogposten
Spårämnesdata (Mn/Ca, Mg/Ca, Sr/Ca) från den bottenlevande foraminiferarten Nonionella stella, provtagen i ytsediment från Santa Barbara bassängen, USA - Trace-elemental data (Mn/Ca, Mg/Ca, Sr/Ca) of the benthic foraminifer Nonionella stella from core-top sediments of the Santa Barbara Basin, USA
No full textDataset of Mn/Ca, Mg/Ca and Sr/Ca of the three most-recently formed chambers (n, n-1 and n-2) of Nonionella stella (CTG-labelled) acquired by Secondary Ion Mass Spectrometry (SIMS; Nordsim, Stockholm, Sweden). Nonionella stella specimens were collected from core-top samples of three sites over a depth-gradient in the Santa Barbara Basin, off Southern California, USA. The data set is part of a study exploring the response of foraminiferal Mn/Ca to changing bottom-water oxygenation and pore-water Mn geochemistry. The data is discussed in: Brinkmann, I., Ni, S., Schweizer, M., Oldham, V. E., Quintana Krupinski, N. B., Medjoubi, K., et al. (2021). Foraminiferal Mn/Ca as bottom-water hypoxia proxy: An assessment of Nonionella stella in the Santa Barbara Basin, USA. Paleoceanography and Paleoclimatology, 36, e2020PA004167. https://doi.org/10.1029/2020PA004167. Please contact the main author for further details ([email protected]). The northern SBB was sampled in May 2018 (cruise SP1811, R/V Robert Gordon Sproul) at site 1 (430 m; 34º 18.6’N, 119º 54.0’W), site 2 (505 m; 34º 20.8’N, 119º 59.0’W) and site 3 (567 m; 34º 19.2’N, 120º 03.4’W). Sediment cores were recovered with a Ocean Instruments MC800 multicorer. The cores were sliced into 0.5 cm sections (‘0–0.5 cm’, ‘0.5–1.0 cm’, ‘1.0–1.5 cm’ and ‘1.5–2.0 cm’; site 1 also 'fluff') and CTG-labelled to identify living foraminifera. Nonionella stella specimens were selected and bleached (NaOCl 5%) prior to epoxy-embedding. Trace element concentrations of test walls were analysed using a CAMECA ims1280 ion microprobe (Nordsim Laboratory, Swedish Museum of Natural History, Stockholm, Sweden); an OKA calcite crystal served as reference material.Dataset över Mn/Ca, Mg/Ca and Sr/Ca från de tre senaste bildade kamrarna (n, n-1, n-2) i skal av Nonionella stella, analyserade genom en jonmikrosond (SIMS; Nordsim, Stockholm, Sverige). Nonionella stella individer provtogs från ytsediment från tre stationer över en djupgradient i Santa Barbara bassängen, södra Kalifornien, USA. Datasetet är en del av en studie för att undersöka hur Mn/Ca kvoten i foraminiferers skal ändras med ändrad syrgaskoncentration. Publikationen där detta dataset ingår finns på https://doi.org/10.1029/2020PA004167. Kontakta huvudförfattaren för fler detaljer ([email protected]). För att använda datasetet måste källa anges. Norra delen av Santa Barbara bassängen provtogs i maj 2018 (expedition SP1811, R/V Robert Gordon Sproul), station 1 (430 m vattendjup; 34º 18.6’N, 119º 54.0’W), station 2 (505 m; 34º 20.8’N, 119º 59.0’W) och station 3 (567 m; 34º 19.2’N, 120º 03.4’W). Sedimenten provtogs med en Ocean Instruments MC800 multicorer. Sedimentkärnorna skivades till 0,5 cm tjocka skivor (‘0–0.5 cm’, ‘0.5–1.0 cm’, ‘1.0–1.5 cm’ and ‘1.5–2.0 cm’; station 1 även det lösa organiska ”fluffet” på överytan'). CTG tillsattes för att särskilja mellan levande och döda foraminiferer. Utvalda (nu döda) individer blektes (NaOCl 5%) innan de bäddades in i epoxy. Koncentrationerna av spårelementinnehållet i skalväggen analyserades genom att använda en CAMECA ims1280 jon mikrosond (Nordsim Laboratory, Swedish Museum of Natural History, Stockholm, Sweden)
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
Coastal signals of environmental changes: foraminifera as benthic monitors
Full text linkClimate changes, tightly linked to anthropogenic activities, are significantly altering environments and ecosystems globally, such as by increasing marine and coastal deoxygenation or occurrences of extreme weather events. The significance of paleoenvironmental and -climate reconstructions, as well as monitoring of current conditions, for unravelling baseline natural variation, today’s changes and potential future impacts, has been recognised by the Intergovernmental Panel on Climate Change (IPCC) reports. However, to access past records of physical and chemical environmental variables, and comprehensively assess ecosystem reactions, reliable and sensitive proxies are critical. This thesis’ focus lies on benthic foraminifera—unicellular protists with mineralised or organic test, abundantly inhabiting ocean and coastal sediments—and their calibration as indicator for a variety of environmental conditions in field-sampling approaches. The research projects follow two general strategic tracks: (I) a biogeochemical assessment of trace-elemental ratios in foraminiferal calcium-carbonate tests using high-resolution, micro-analytical techniques; (II) a molecular approach investigating foraminiferal environmental DNA derived from coastal sediments. Papers I and II concern the calibration of the benthic foraminiferal Mn/Ca proxy for marine oxygenation conditions in modern field studies. Trace-element concentrations and distributions were measured by plasma-, laser- and synchrotron-based analyses in a high-resolution, individual-foraminifera approach, and interpreted in the context of ambient physical and chemical conditions of the water column, pore-waters and sediments (including oxygen and manganese concentrations). Investigating two coastal systems with almost permanently severely oxygen-deficient bottom-waters (Santa Barbara Basin, Paper I), and undergoing a seasonal oxygenation cycle across the low- to well-oxygenated range (Gullmar Fjord, Paper II), respectively, demonstrated the utility of the Mn/Ca proxy for indicating low-oxygen conditions specifically. Continued calibration efforts under consideration of ambient oxygenation and redox regimes may open further possibilities of quantitative oxygen reconstructions. Paper III explores the use of coastal, benthic Ba/Ca records as indicator of riverine runoff and drought on land across the years 2018 and 2019, characterised by severe heat and drought, and warm and wet conditions, respectively. Benthic Ba/Ca correlated significantly with the hydroclimate conditions, as inferred from extensive meteorological and hydrological data sets of the region, highlighting qualitative proxy potential for paleo-drought reconstructions. Based on ambient sediment and pore-water geochemistry, we discuss mediation of water-column transport and pore-water Ba cycling by Fe and Mn oxides. All three investigations of these geochemical proxies (Paper I–III) highlighted the significance of biological controls on foraminiferal TE/Ca, which are species-specific and, thus, should be a deciding factor in choosing proxy candidate species. In particular the influences of micro-habitat distribution and utilised metabolic pathways by foraminifera are discussed in detail. In Paper IV foraminiferal biodiversity and assemblage responses to natural and anthropogenic environmental trends in a fjord system (Swedish west coast) are documented in a metabarcoding approach. Environmental DNA successfully tracked biodiversity and community composition changes associated with contrasting ecosystems but showed damped sensitivity to environmental variability on sub-annual time-scales. Overlaps and discrepancies between molecular and traditional, observation-based assessment techniques, as well as future trajectories to resolve uncertainties are discussed. Overall, this thesis solidifies and expands the currently available proxy toolbox for reconstructions of both coastal low-oxygen, as well as terrestrial hydroclimate conditions. The findings contribute towards filling current knowledge gaps pertaining to biotic impacts on foraminifera-derived biogeochemical signals and methodological uncertainties in metabarcoding approaches and highlight the significance of implementing molecular techniques in conventional foraminiferal assemblage studies
- …
