1,720,965 research outputs found
Late Holocene environmental change: evidence from Lake Xiaolongwan, north east China and Lake Arachlei, south eastern Siberia
Get PDFThis project addresses the increasing need for high-resolution proxy studies of environmental
change over the late Holocene from regions in northern Eurasia. The late Holocene has been
identified as a key timeframe for investigating environmental change (e.g. PAGES Focus 2) due
to the relatively small changes in boundary conditions. In particular, this project focuses on two
sites; Lake Xiaolongwan, north east China, sensitive to changes in summer (EASM) and winter
(EAWM) monsoonal intensity and Lake Arachlei, south east Siberia, sensitive to changes in
Westerly transport and Siberian High intensity.
This project provides a detailed high-resolution reconstruction of diatoms and bulk organic
isotopes from cores collected at each of these sites. The c. 2000 year record from Lake
Xiaolongwan, has an age model derived from varve counting, 210Pb and SCPs. Ecological
interpretations of diatom changes suggests a long term trend towards decreased lake water
level and increased lake productivity (after c. 1650 years BP). Superimposed upon the trend are
significant periods of assemblage changes thought to represent intensified EAWM intensity,
occuring between c. 1450-1350 and 600-400 years BP, which are coincident with evidence of
north Atlantic ice raft debris (IRD) events.
At Lake Arachlei, a similar trend of decreasing lake levels is also identified over the c. 3000 year
record (based on a 14C and 210Pb age model). Significant assemblage changes are
demonstrated between c. 3000-2800, 1450-1350 and 500-400 years BP, thought to indicate
reduced Westerly transport to the region. These periods are coincident with Bond events 2, 1
and 0. This project demonstrates the role of teleconnections in the late Holocene, which may be
responsible for environmental change. Nevertheless, the dramatic change identified in the Lake
Xiaolongwan record after c. 1950 cannot be attributed to evidence of global warming in the
region due to the demonstrated evidence of anthropogenic impacts (XRF and SCPs) in this
otherwise perceived pristine region
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
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
The stable isotope composition of organic and inorganic fossils in lake sediment records: current understanding, challenges, and future directions
Get PDFThis paper provides an overview of stable isotope analysis (H, C, N, O, Si) of the macro and microscopic remains from aquatic organisms found in lake sediment records and their application in (palaeo)environmental science. Aquatic organisms, including diatoms, macrophytes, invertebrates, and fish, can produce sufficiently robust remains that preserve well as fossils and can be identified in lake sediment records. Stable isotope analyses of these remains can then provide valuable insights into habitat-specific biogeochemistry, feeding ecology, but also on climatic and hydrological changes in and around lakes. Since these analyses focus on the remains of known and identified organisms, they can provide more specific and detailed information on past ecosystem, food web and environmental changes affecting different compartments of lake ecosystems than analyses on bulk sedimentary organic matter or carbonate samples. We review applications of these types of analyses in palaeoclimatology, palaeohydrology, and palaeoecology. Interpretation of the environmental ‘signal’ provided by taxon-specific stable isotope analysis requires a thorough understanding of the ecology and phenology of the organism groups involved. Growth, metabolism, diet, feeding strategy, migration, taphonomy and several other processes can lead to isotope fractionation or otherwise influence the stable isotope signatures of the remains from aquatic organisms. This paper includes a review of the (modern) calibration, culturing and modeling studies used to quantify the extent to which these factors influence stable isotope values and provides an outlook for future research and methodological developments for the different examined fossil groups
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