1,720,958 research outputs found
3D Flow Field of Chlamydomonas reinhardtii and related analyses
No full textExperimental, theoretical, and simulation data in .csv. .mat, .m, and .dat formatsThis data set contains raw data for figures in the manuscript "Seeing new depths: Three-dimensional flow of a free-swimming alga", under review for publication in Physical Review X as of January 2026. The set contains experimental flow field data obtained using holographic microscopy combined with particle tracking velocimetry, theoretical model flow field calculated using the three-Stokeslet model, and simulation flow field obtained through regularized Stokeslet (RS) simulations. Various analyses were performed on these flow fields to obtain information such as flow magnitude decay, energy dissipation, swimming and feeding efficiencies, vortex line structures, etc., which are included in this data set.David and Lucile Packard FoundationU.S. National Science Foundation (NSF), BMMB-2242095 and 2242096/2438345Cheng, Xiang; Pradipta, Gregorius. (2026). 3D Flow Field of Chlamydomonas reinhardtii and related analyses. Retrieved from the Data Repository for the University of Minnesota (DRUM), https://doi.org/10.13020/49g2-mb02
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
An exploration of microbial motility and active fluids through the lens of 3D flow visualization
No full textUniversity of Minnesota Ph.D. dissertation. October 2025. Major: Chemical Engineering. Advisors: Xiang Cheng, Satish Kumar. 1 computer file (PDF); x, 133 pages.The study of microbial motility has progressed significantly in the past decade in nosmall part due to experimental visualization of the flow induced by freely swimming microorganisms, yet such visualizations have been constrained to two dimensions and many three-dimensional swimming behaviors remain inadequately defined. This thesis combines experimental visualization, hydrodynamic modeling, and numerical simulations to characterize microbial flow fields in three dimensions and changes to such flow fields due to various factors. First, we present the first experimental measurements of the three-dimensional (3D) flow field of freely swimming Chlamydomonas reinhardtii, visualized by holographic microscopy.
The characterized flow field revealed how the well-known 2D flow structures extend to 3D in both time-averaged and time-resolved, revealing complex structures that otherwise remain unclear from visualization of the 2D flow. In particular, the time-resolved vortex structures in 3D exhibit dynamics that are rich and unexpected in inertialess flow. The characterized 3D flow field also yields a more rigorous quantification of the energy expenditure, along with both the swimming and feeding efficiencies of the alga, providing a more accurate estimate of measures of physiological metric related to motility. Thus, complete characterization of the 3D flow field around C. reinhardtii advances our understanding of its motility and provides a powerful method to experimentally visualize flows around microorganisms in 3D.
Second, we examine the changes in C. reinhardtii flow fields due to physical changes to the cell, namely through two mutations in the length of its two flagella, one for shorter length and another for longer. Our measurements show, on time average, the forward shift of lateral vortex and hyperbolic stagnation point, along with the change in vortex orientation as the flagella length increases. The time-resolved flow fields show a similar change from puller to pusher flow between the mutants and the wild-type, though with notably different structures during the transition arising from the differing flagellar waveforms. From the characterized time-resolved flow fields, we quantify the changes in metrics such as swimming and feeding efficiencies to gain insight into physiological changes brought about by the change of flagella length.Third, we turn our attention into the propulsion of the bacterium Escherichia coli in the bulk and near a solid surface, utilizing hydrodynamic modeling to predict its 3D flow field. We extend upon the classic force dipole representation of the bacterium by adding two point torques, allowing us to capture the near-field rotational flow induced by the rotation of the body and flagella while preserving the far-field structure of a pusher-type force dipole flow in the bulk. Close to a solid surface, the characterized flow structure loses its mirror symmetry along the y = 0 and x = 0 planes, resulting in a clockwise ”twist” in the in-plane flow structure, providing us with an explanation to why the bacterium constantly turns clockwise while swimming next to a solid surface.
Lastly, we expand beyond the scope of a single swimming microorganism and probe the collective effect of numerous microswimmers inducing flow in a thin liquid film. Through both linear stability analysis and nonlinear simulations, we find that contractile active units have a destabilizing effect on the film, introducing new instabilities not commonly seen in passive films, while extensile active units have the opposite effect. This suggests a promising route to mitigate instabilities by introducing some level of extensile activity to an otherwise passive thin liquid film. Together, the work detailed in this thesis advances our understanding of microbial
motility through the characterization of the induced flow, providing insight into the hydrodynamic and biological aspects of the propulsion of a freely swimming microorganism.Pradipta, Gregorius. (2025). An exploration of microbial motility and active fluids through the lens of 3D flow visualization. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/278796
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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