1,720,963 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
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
Three-dimensional polymeric topographies for neural interfaces
No full textOptimal integration of artificial interfaces with neural tissue is critical to develop novel neural regeneration scaffolds and neuroprosthetic implants. The topography of the implantable device can promote nerve repair as it affects neuronal growth via contact guidance. Furthermore, topography may be utilized to establish a stable and close contact with neural tissue required to improve the electrical neuron-device coupling. The goal of this thesis is to investigate the effects of nano- and microtopographies on the development and adhesion of embryonic cortical neurons. Three different polymer surfaces with topographical structures of varying dimensions were used – namely, i) anisotropic poly(N-isopropylacrylamide) (PNIPAAm) nanogels, ii) isotropic OrmoComp nanopillars, and iii) isotropic poly(3-hexylthiophene-2,5-diyl) (P3HT) micropillars. Anisotropic PNIPAAm nanogel arrays induced perpendicular alignment of major neurites and accelerated axon development, resulting in an ~80% increase in axon length compared to either unstructured nanogel substrates or glass substrates. Despite being relatively soft compared to glass substrates, unstructured nanogels did not induce substantial changes in neuronal morphology, indicating that neurons “perceive” unstructured nanogels as equivalent to glass. Isotropic OrmoComp nanopillars aligned neurites along topographically dictated angles (0°, 90°) with higher pillars (400 nm) confining neurites to a greater extent compared to lower pillars (100 nm). Furthermore, higher nanopillars promoted growth cone elongation and axon development resulting in ~40% longer axons compared to flat substrates. A larger surface area of the nanopillars was correlated with higher density of point contact adhesions in the growth cone and a reduction in actin retrograde flow rates, indicating a stronger coupling between the growth cone and thesubstrate which enables accelerated and persistent neurite outgrowth. Furthermore, F-actin accumulations and paxillin-rich adhesions were observed in the neuronal soma at nanopillars, indicating that neurons form a close contact with the nanoscale topography. Isotropic P3HT micropillars represent a relatively soft interface that enables neurons to achieve a close and conformal contact mediated by membrane rearrangements. Optical stimulation of embryonic neurons growing on photosensitive P3HT substrates induced a significant increase in neurite outgrowth compared to control substrates without deleterious effects on neuronal viability. The effects of photostimulation were further enhanced by the microtopography, indicating that P3HT acts as an active interface with possible applications in in vitro neural regeneration scaffolds. Furthermore, MEAs functionalized with P3HT micropillars yielded a significant increase in the signal-to-noise ratio (SNR) compared to flat MEAs, indicating that micropillars improve the cell-electrode coupling. Optical stimulation of spontaneous network activity on P3HT-functionalized MEAs induced neuronal firing and increased the firing rate. Although the process was not fullyreproducible, optical excitation of P3HT interfaces provides a promising strategy for modulating network activity in a non-invasive manner
Three-Dimensional Polymeric Topographies for Neural Interfaces
No full textOptimal integration of artificial interfaces with neural tissue is critical to develop novel neural regeneration scaffolds and neuroprosthetic implants. The topography of the implantable device can promote nerve repair as it affects neuronal growth via contact guidance. Furthermore, topography may be utilized to establish a stable and close contact with neural tissue required to improve the electrical neuron-device coupling. The goal of this thesis is to investigate the effects of nano- and microtopographies on the development and adhesion of embryonic cortical neurons. Three different polymer surfaces with topographical structures of varying dimensions were used – namely, i)anisotropic poly(N-isopropylacrylamide) (PNIPAAm) nanogels, ii) isotropic OrmoComp nanopillars, and iii) isotropic poly(3-hexylthiophene-2,5-diyl) (P3HT) micropillars. Anisotropic PNIPAAm nanogel arrays induced perpendicular alignment of major neurites and accelerated axon development, resulting in an ~80% increase in axon length compared to either unstructured nanogel substrates or glass substrates. Despite being relatively soft compared to glass substrates, unstructured nanogels did not induce substantial changes in neuronal morphology, indicating that neurons “perceive” unstructured nanogels as equivalent to glass. Isotropic OrmoComp nanopillars aligned neurites along topographically dictated angles (0°, 90°) with higher pillars (400 nm) confining neurites to a greater extent compared to lower pillars (100 nm). Furthermore, higher nanopillars promoted growth cone elongation and axon development resulting in ~40% longer axons compared to flat substrates. A larger surface area of the nanopillars was correlated with higher density of point contact adhesions in the growth cone and a reduction in actin retrograde flow rates, indicating a stronger coupling between the growth cone and the substrate which enables accelerated and persistent neurite outgrowth. Furthermore, F-actin accumulations and paxillin-rich adhesions were observed in the neuronal soma at nanopillars, indicating that neurons form a close contact with the nanoscale topography. Isotropic P3HT micropillars represent a relatively soft interface that enables neurons to achieve a close and conformal contact mediated by membrane rearrangements. Optical stimulation of embryonic neurons growing on photosensitive P3HT substrates induced a significant increase in neurite outgrowth compared to control substrates without deleterious effects on neuronal viability. The effects of photostimulation were further enhanced by the microtopography, indicating that P3HT acts as an active interface with possible applications in neural regeneration scaffolds. Furthermore, MEAs functionalized with P3HT micropillars yielded a significant increase in the signal-to-noise ratio (SNR) compared to flat MEAs, indicating that micropillars improve the cell-electrode coupling. Optical stimulation of spontaneous network activity on P3HT-functionalized MEAs induced neuronal firing and increased the firing rate. Although the process was not fully reproducible, optical excitation of P3HT interfaces provides a promising strategy for modulating network activity in a non-invasive manner
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
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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