1,721,275 research outputs found
Impacts of Multiple Environmental Change Drivers on Growth of European Beech (Fagus sylvatica): Forest History Matters
No full textThe Long-wavelength Earth model (LOWE) at 50 s Minimum Period
No full text<p>This repository holds an updated version of the Long-wavelength Earth Model (LOWE) as presented in Thrastarson et al. (2022). Since the original publication, the model has been further developed, with several full-waveform inversion updates down to a minimum period of 50 s. This version of LOWE in this repository is a submodel within the second generation of the Collaborative Seismic Earth Model (CSEM2, Noe et al. (submitted)).</p>
<p>Methodological developments and a description of the data are explained in detail in the publication about the final version of LOWE, now called REVEAL (Thrastarson et al., 2024).</p>
HMCLab: a framework for solving diverse geophysical inverse problems using the Hamiltonian Monte Carlo method
Full text linkThe use of the probabilistic approach to solve inverse problems is becoming
more popular in the geophysical community, thanks to its ability to address
nonlinear forward problems and to provide uncertainty quantification. However,
such strategy is often tailored to specific applications and therefore there is
a lack of a common platform for solving a range of different geophysical
inverse problems and showing potential and pitfalls. We demonstrate a common
framework to solve such inverse problems ranging from, e.g, earthquake source
location to potential field data inversion and seismic tomography. Within this
approach, we can provide probabilities related to certain properties or
structures of the subsurface. Thanks to its ability to address high-dimensional
problems, the Hamiltonian Monte Carlo (HMC) algorithm has emerged as the
state-of-the-art tool for solving geophysical inverse problems within the
probabilistic framework. HMC requires the computation of gradients, which can
be obtained by adjoint methods, making the solution of tomographic problems
ultimately feasible. These results can be obtained with "HMCLab", a tool for
solving a range of different geophysical inverse problems using sampling
methods, focusing in particular on the HMC algorithm. HMCLab consists of a set
of samplers and a set of geophysical forward problems. For each problem its
misfit function and gradient computation are provided and, in addition, a set
of prior models can be combined to inject additional information into the
inverse problem. This allows users to experiment with probabilistic inverse
problems and also address real-world studies. We show how to solve a selected
set of problems within this framework using variants of the HMC algorithm and
analyze the results. HMCLab is provided as an open source package written both
in Python and Julia, welcoming contributions from the community.Comment: 21 pages, 4 figure
Correction to: Provenance- and life-history stage-specific responses of the dwarf shrub Calluna vulgaris to elevated vapour pressure deficit
No full textGoing 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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