1,720,957 research outputs found
Investigating future precipitation changes over China through a high-resolution regional climate model ensemble
Full text linkDue to climate change, rising temperature around the world will have a great potential to influence the global hydrologic cycle, thus leading to substantial changes in the spatial and temporal patterns of precipitation. In this study, the effects of global warming on the regional hydrologic cycle, particularly on the spatiotemporal patterns of precipitation, over China are investigated through a high-resolution regional climate ensemble. In detail, the PRECIS regional climate modeling system is employed to simulate the regional climate over China from 1950 to 2099 with a fine resolution of 25 km, driven by the boundary conditions from a four-member HadCM3-based perturbed-physics ensemble (i.e., HadCM3Q0, Q1, Q7, and Q13) and the ECHAM5 model. Historical simulations of the PRECIS ensemble are first compared to the observations to validate its performance in capturing both the spatial and temporal patterns of precipitation. The comparisons show that the PRECIS ensemble is likely to overestimate precipitation in the south and exhibits slight dry biases in the northwest and southeast coasts of China. The projections from the PRECIS ensemble for future periods (i.e., 2020s, 2050s, and 2080s) are then analyzed to help understand how the regional characteristics of precipitation will be affected in the context of global warming. It is shown that the annual mean precipitation over China is likely to increase throughout the 21st century (i.e., by 0.078 mm/d in 2020s, 0.218 mm/d in 2050s, and 0.360 mm/d in 2080s). This may suggest that the rising temperature due to climate change will intensify the regional hydrologic cycles in China. However, apparent spatial and temporal variations are also reported in the projected precipitations from the PRECIS ensemble. For example, bigger changes in precipitation are usually observed in summer; projected precipitation changes in the southeast are apparently higher than other regions. In addition, the results show that the fluctuation range of the ensemble simulations will increase with time periods from 2020s to 2080s, indicating that the longer the projecting periods, the more uncertain the projections will be
High-resolution temperature and precipitation projections over Ontario, Canada: a coupled dynamical-statistical approach
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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
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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