1,720,996 research outputs found
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
Disentangling composite forcings on river channel steepness in heterogeneous landscapes
Get PDFEarly geomorphological studies quickly realised the close relationship between the geometrical characteristics of river networks with the geological, tectonic and climatic context of the regions the river crosses - the most striking example perhaps being the upstream migration of steepened reaches (or “knickpoints”), which rejuvenate landscapes following a base level change via faulting or eustatic variations. Amongst all the morphologies related to the river network, channel gradient has been a particularly important one: following the observation that declivity enhances erosion, any forcing affecting the channel slope potentially also affects erosion and creates a signal that can be interpolated through space and time to reconstruct climatic or tectonic events modulated by local lithology. Parallel to these qualitative observations, geomorphological studies developed tools and metrics to quantify the large-scale shape of river long profiles. Rivers systematically steepen towards the headwaters, which makes the direct use of river slope difficult, so several authors successfully developed a semi-empirical relationship describing the systematic increase of channel gradient with a power-law relationship. This relationship links the steepening component (ks) to the rate at which slope increases as drainage area decreases (θ); later followed by a normalised river length coordinate Χ. Later work on this topic demonstrated a positive relationship between these metrics and the underlying tectonic or lithologic forcings, allowing the systematic comparison of different field sites across the world and large-scale testing of the early qualitative observations. The rise in availability of global scale Digital Elevation Models and external proxies to quantify exhumation/erosion rates (e.g. thermochrononometers, CRN), has made such large scale studies increasingly fast and accessible, making the geomorphometrics described above widely used as spatial and temporal interpolations of tectonics and climatic variations. However, (i) the metrics are affected by different forcings, meaning that a single morphology can be generated by a range of different factors and hence potentially misinterpreted, and (ii) θ varies spatially and will determine the normalisation parameter to calculate ks and Χ. This thesis focuses on developing and applying tools to investigate the different expression of these metrics in heterogeneous landscapes. First, I describe an algorithm to extract and quantify knickpoint morphologies. The aim of this algorithm is to allow the objective comparison of knickpoints in different contexts. They are quantified using ks and sudden changes in elevation in order to detect the location and the magnitude of the knickpoints. I explore the performance and limitations of the algorithm in different settings, and describe how to constrain and interpret this novel work. Secondly, I explore the spatial variability of θ in order to achieve multiple goals. (i) I develop and thoroughly test a method to finely explore the variations of θ while also assessing how a specific θ value fits a watershed in case a non-optimal value has to be fixed. (ii) From the observed range of θ variation, I analytically and numerically explore how a non-optimal θ can affect ks and Χ, respectively. I identify cases where this caveat can lead to the generation/exaggeration of spurious signals or to the diminution/inversion of existing ones. Thirdly, I apply such algorithms, alongside with field measurements and observations, in a heterogeneous landscape: the eastern Carpathians. The eastern Carpathians are highly heterogeneous with (i) sharp lithologic contrasts, (ii) high spatial and temporal contrasts in vertical motion, and (iii) spatially variable θ. I demonstrate with systematic comparison of steepness across θ with lithologic and tectonic forcings that in that case lithology is the dominant forcing expressed in ks, although tectonic forcing can be retrieved. I discuss and successfully integrate my conclusions into local tectonic models and show larger scale implications for interpreting these metrics
Supplemental data table for Isolating lithologic versus tectonic signals of river profiles to test orogenic models for the Eastern and Southeastern Carpathians
No full textThis dataset contains a table of Schmidt Hammer data points acquired during a field campaign in the Eastern Carpathians in 2018. It is a supplemental material to the manuscript Isolating "lithologic versus tectonic signals of river profiles to test orogenic models for the Eastern and Southeastern Carpathians" submitted to JGR-Earth Surface.
Abstract of the paper:
Fluvial morphology is affected by a wide range of forcing factors, which can be external, such as faulting and changes in climate, or internal, such as variations in rock hardness or degree of fracturing. It is a challenge to separate internal and external forcing factors when they are co-located or occur coevally. Failure to account for both factors leads to potential misinterpretations. For example, steepening of a channel network due to lithologic contrasts could be misinterpreted as a function of increased tectonic displacements. These misinterpretations are enhanced over large areas, where landscape properties needed to calculate channel steepness (\textit{e.g.} channel concavity) can vary significantly in space. In this study, we investigate relative channel steepness over the Eastern Carpathians, where it has been proposed that active rock uplift in the Southeastern Carpathians gives way N- and NW-wards to ca. 8 Myrs of post-orogenic quiescence. We develop a technique to quantify relative channel steepness based on a wide range of concavities, and show that the main signal shows an increase in channel steepness from east to west across the range. Rock hardness measurements and geological studies suggest this difference is driven by lithology. When we isolate channel steepness by lithology to test for ongoing rock uplift along the range, we find steeper channels in the south of the study area compared to the same units in the North. This supports interpretations from longer timescale geological data that active rock uplift is fastest in the southern Southeastern Carpathians
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
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