Burrow refilling behavior of Aporrectodea turgida (Eisen) and Lumbricus terrestris L. as revealed by X-ray computed tomography scanning: Graphical and quantitative analyses

2015 ◽  
Vol 95 (3) ◽  
pp. 231-235 ◽  
Author(s):  
Joann K. Whalen ◽  
Liwen Han ◽  
Pierre Dutilleul

Whalen, J. K., Han L. and Dutilleul, P. 2015. Burrow refilling behavior of Aporrectodea turgida (Eisen) and Lumbricus terrestris L. as revealed by X-ray computed tomography scanning: Graphical and quantitative analyses. Can. J. Soil Sci. 95: 231–235. Solute and gas transport through earthworm burrows is altered when burrows become refilled. Earthworm burrow refilling was evaluated with non-invasive X-ray computed tomography in undisturbed soil cores. Proportionally, Lumbricus terrestris refilled burrows had more air-filled space left around their perimeter than those of Aporrectodea turgida, which often were completely refilled.

2011 ◽  
Vol 110-116 ◽  
pp. 808-815 ◽  
Author(s):  
Jagadeesha Kumar ◽  
Abdul Hadi G. Abulrub ◽  
Alex Attridge ◽  
Mark A. Williams

X-Ray Computed Tomography (CT) scanning is an effective method for estimating the porosity of various engineering materials and biomedical specimens such as tissue scaffolds and bones. However, the scanning and analysis parameters play a significant role in the accuracy of the porosity value determined from CT scan. This paper presents details of an investigation carried out to understand the effect of system parameters, namely the voxel size, X-ray focal spot size and segmentation threshold, on the estimated porosity by taking an example of safety-critical foam used for impact protection applications. Different voxel resolutions and focal spot sizes are selected in a total of 12 scanning tests and the effect of segmentation threshold is analyzed on each of these tests. The study indicates that the obtained porosity value is greatly influenced by the choice of voxel size at larger spot sizes and less influenced at smaller spot sizes. The threshold also has significant effect on the porosity value, especially at larger voxel sizes.


2017 ◽  
Vol 31 (6) ◽  
pp. 797 ◽  
Author(s):  
Milan Koch ◽  
Seyit A. Kamanli ◽  
Oliver Crimmen ◽  
Chia-Wei Lin ◽  
Paul F. Clark ◽  
...  

In his catalogue of British Museum Crustacea, Adam White listed two swimming crabs from Borneo as a new species, Amphitrite argentata, but he did not provide a description and therefore the name was a nomen nudum. Later, Alphonse Milne-Edwards described the larger of these male specimens as Neptunus argentatus and credited the species to White. Now assigned to Monomia Gistel, 1848, M. argentata was recently considered to represent a species-complex; however, its nomenclature and taxonomy have been confused over a long period of time. Furthermore, the larger syntype examined by Alphonse Milne-Edwards is no longer extant. The present study compared the smaller extant M. argentata male of White, here designated as the lectotype, with the description by A. Milne-Edwards. This dried specimen was re-examined using X-ray and computed tomography scanning techniques in order to reveal the general morphology of the first male gonopod (G1). Fresh material was collected and identified with confidence as M. argentata. This species was redescribed to modern standards including illustrations, details of coloration and new scanning electron micrographs of the G1 were provided. The validity of this species was further endorsed by comparing DNA sequences with congeners from the South China Sea. To conclude, the type status, authority and associated species-complex of M. argentata are discussed.


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