We develop an algorithm of computerized ionospheric tomography (CIT) to infer information on the vertical and horizontal structuring of electron density during nighttime medium‐scale traveling ionospheric disturbances (MSTIDs). To facilitate digital CIT we have adopted total electron contents (TEC) from a dense Global Positioning System (GPS) receiver network, GEONET, which contains more than 1000 receivers. A multiplicative algebraic reconstruction technique was utilized with a calibrated IRI‐2012 model as an initial solution. The reconstructed F2 peak layer varied in altitude with average peak‐to‐peak amplitude of ~52 km. In addition, the F2 peak layer anticorrelated with TEC variations. This feature supports a theory in which nighttime MSTID is composed of oscillating electric fields due to conductivity variations. Moreover, reconstructed TEC variations over two stations were reasonably close to variations directly derived from the measured TEC data set. Our tomographic analysis may thus help understand three‐dimensional structure of MSTIDs in a quantitative way.

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Background The aim of this article is to evaluate the difference in skills acquisition of two end-to-end microvascular anastomosis techniques-the triangulation and biangulation-in early microsurgery training. Method In this study, 32 candidates ranging from medical students to higher surgical trainees underwent a 5-day basic microsurgery course. On days 3 and 5 of the course, candidates performed two end-to-end anastomoses on cryopreserved rat aortas. One anastomosis was performed using the biangulation technique and the other using the triangulation technique. Candidates were randomized to the order of technique performed. Structural patency, errors performed, and suture distribution were evaluated randomly by a blinded reviewer using the anastomosis lapse index score and ImageJ (U.S. National Institutes of Health, Bethesda, MD) Software. Results A total of 128 anastomoses were evaluated during the study period. A total of six anastomoses performed with the biangulation technique, and four anastomoses with the triangulation technique, were physically occluded on day 3 of the course. On day 5, two biangulation technique anastomoses and one triangulation technique produced a nonpatent outcome. There was a statistically significant difference of patency rate between the 2 days of evaluation confirming evidence of skill acquisition but no statistically significant difference between the two techniques in relation to anastomotic patency, errors performed, or suture placement quality. Conclusion The biangulation and triangulation techniques of microvascular anastomosis produce similar outcomes in relation to vessel structural patency and quality of anastomosis when taught in early stages of microsurgery training. Our results suggest that both techniques are equally suitable in training novices, basic microsurgical skills.

Evaluation of anastomosis structural patency and quality in nonliving models is possible. The proposed error list showed construct and predictive validity. The anastomosis lapse index can serve as a formative and summative assessment tool during microvascular training.

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