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31.
In this paper, we present a movement-based assay to observe adaptability in Caenorhabditis elegans locomotion behavior. The assay comprises a series of sinusoidal microchannels with a fixed wavelength and modulating (increasing or decreasing) amplitude. The channel width is comparable to the body diameter of the organism. Worms are allowed to enter the channel from the input port and migrate toward the output port. Within channel sections that closely match the worm's natural undulations, the worm movement is relatively quick and steady. As the channel amplitude increases or decreases along the device, the worm faces difficulty in generating the propulsive thrust, begins to slow down and eventually fails to move forward. A set of locomotion parameters (i.e., average forward velocity, number and duration of stops, range of contact angle, and cut-off region) is defined for worm locomotion in modulated sinusoidal channels and extracted from the recorded videos. The device is tested on wild-type C. elegans (N2) and two mutants (lev-8 and unc-38). We anticipate this passive, movement-based assay can be used to screen nematodes showing difference in locomotion phenotype. 相似文献
32.
Elizabeth Cay (1771–1831), the grandmother of the Scottish physicist James Clerk Maxwell (1831–1879), was a talented amateur pastellist; several of her pastel portraits survive as does her set of pastels. She studied with Archibald Skirving (1749–1819), a Scottish miniature painter who later in life turned to larger-scale portraiture in pastel and served as drawing master to the Edinburgh elite. Cay's pastels are not fabricated sticks but consist of powdered pigment housed in various glass and ceramic containers and were apparently applied by stumps, still in her workbox, or brushes. The Cay color samples were identified by spectrographic analysis, polarized light microscopy, and microchemical tests which, in addition, indicated that a number of pigment mixtures present gave specific hues in keeping with earlier treatise accounts of the preparation of a pastel gamut for practical use. Elizabeth Cay's pastel workbox may be rare surviving evidence of one way, more common that we appreciate today, in which amateurs, and perhaps professionals, practiced pastel painting. 相似文献
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Examinations and higher education: a survey of the literature 总被引：1，自引：0，他引：1
Roy Cox 《Higher Education Quarterly》1967,21(3):292-340
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