1,721,051 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
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
Pushing stem cells toward bone lineage through ultrasound stimulation
No full textWhen human mesenchymal stem cells (hMSCs) are cultured inside a 3D collagen meshwork, they become a potential tissue engineering bone graft alternative. However, the in vitro osteogenesis rate of hMSCs is slow, leading to a low mineral deposition.
To enhance the osteogenic differentiation of hMSCs, low intensity pulsed ultrasound (LIPUS) was employed as an external stumulus. The present study demonstrated the feasibility of employing daily LIPUS exposure for enhancing osteogenesis in vitro. Exposure of seven consecutive days LIPUS, each of 30 minutes duration, did not affect the cell viability, and the organization of hMSCs within the collagen meshwork was not disturbed. The calcium deposition within the collagen meshwork was enhanced after seven days of exposure. The osteoinductivity was also upregulated at the early period of culture.
In order to optimizing the enhancement effects of LIPUS, various ultrasound parameters, including intensity, exposure duration and exposure repetition were investigated. Results showed the LIPUS enhancement effects are dose dependent, LIPUS exposure should be longer than 10 minutes/day in order to elicit a significant effect. Calcium deposition was higher when LIPUS exposure was done twice per day instead of one. Although individual variation exists, optimal LIPUS intensity range was between 60-120 mW/cm2 ISATA (Spatial Average Temporal Average Intensity).
The interaction mechanism between LIPUS and cells was also investigated. Microbubbles were added to the culture during LIPUS exposure to find out whether cavitation is involved in the interaction. Flow sensor primary cilium was also studied in order to verify that ultrasound is transduced through fluid flow. Results showed cavitation may not be a contributing factor to osteogenesis, and primary may be involved in the transduction of LIPUS stimulation.
This study demonstrated that osteogenesis of hMSCs encapsulated in collagen constructs could be enhanced by LIPUS. The LIPUS parameters were also optimized. The LIPUS interaction pathways were also being better understood. This thesis study will be a paradigm for cellular mechanotransduction studies and put an important step forward for therapeutic ultrasound.published_or_final_versionElectrical and Electronic EngineeringMasterMaster of Philosoph
Improving the contrast resolution of synthetic aperture imaging: motion artifact reduction based oninterleaved data acquisition
No full textpublished_or_final_versionElectrical and Electronic EngineeringMasterMaster of Philosoph
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
Adaptive flow detector and estimator for ultrasound high frame rate vector flow imaging
No full textCardiovascular diseases is a leading cause of death worldwide and improvement of the
corresponding screening tool is the best way to deal with this clinical problem. In this thesis
we attempted to develop a framework of ultrasound high frame rate vector flow imaging
(VFI) by emphasizing on the design of corresponding flow detector and flow estimator. We
believe that the high temporal resolution and the complex blood flow visualization ability of
high frame rate VFI enables it to be further developed as a reliable flow imaging modality
for cardiological examination.
In order to achieve high temporal resolution, fast data acquisition algorithm was applied
in the framework. Doppler signals acquired using this acquisition algorithm have two
unique characteristics comparing with conventional data acquisition algorithm: (1) widen
spectral bandwidth and (2) greater clutter to blood signal ratio. These signal characteristics
give rise to unique signal processing. In addition, complex blood flow pattern, which
is common in cardiological examination, induces extra challenges in implementing high
frame rate VFI. In this thesis, flow detector which is adaptive to different flow scenarios
and high dynamic range 2D flow estimator were presented.
The proposed flow detector employes K-means++ clustering algorithm to classify clutter
components from acquired Doppler signals. As a performance analysis, Field II simulation
studies were performed by a parabolic flow phantom (flow velocity: 10mm/s to
200mm/s; tissue motion: 10mm/s; beam-flow angle: 60?). The post-filtered Doppler power
map and BCR were used as qualitative and quantitativemeasures of detectors performance.
Analyzed result has indicated that, as compared with clutter downmixing detector and
eigen-based detector, the proposed flow detector could classify and suppress clutter component
more effectively. Results also suggested that the proposed flow detector is more
adaptive to slow flow scenarios where existing flow detectors failed to distinguish between
blood and clutter components.
For the proposed flow estimator, it was characterized by the interpolation of speckle
tracking results in Lagrangian reference frame. The estimation bias and RMS error were
calculated for different flow scenarios (flow velocity: 100mm/s to 500mm/s; beam-flow
angle: 15? to 60?). It was found that the proposed flow estimator provides higher dynamic
range than conventional speckle tracking-based flow estimator. Nonetheless, it is also observed
that the estimation variances and errors increases in slow flow scenarios.
In order to demonstrate the medical potential of the proposed high frame rate VFI
framework. A carotid bifurcation simulation model with realistic blood flow pattern calculated
using computational fluid dynamic software was applied in the performance evaluation
study. In the VFI image obtained, complex blood flow pattern was readily visualized.
In contrast, conventional ultrasound flow imaging was only able to estimate axial velocity
map and thus lead to many ambiguities in analyzing the complex blood flow pattern. It
proved that ultrasound high frame rate VFI has the potential to be further developed into a
new cardiological examination technique.published_or_final_versionElectrical and Electronic EngineeringMasterMaster of Philosoph
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