Evaluation of Atmospheric 3-Day Waves as a Source of Day-to-Day Variation of the Ionospheric Longitudinal Structure.

We report for the first time the day-to-day variation of the longitudinal structure in height of the F2 layer (hmF2) in the equatorial ionosphere using multi-satellite observations of electron density profiles by the Constellation Observing System for Meteorology, Ionosphere and Climate-2 (COSMIC-2). These observations reveal a ~3-day modulation of the hmF2 wavenumber-4 structure viewed in a fixed local time frame during January 30-February 14, 2021. Simultaneously, ~3-day planetary wave activity is discerned from zonal wind observations at ~100 km by the Ionospheric Connection Explorer (ICON) Michelson Interferometer for Global High-Resolution Thermospheric Imaging (MIGHTI). This signature is not observed at ~180-250 km altitudes, suggesting the dissipation of this wave below the F-region. We propose that the 3-day variation identified in h mF2 is likely caused by the planetary wave-tide interaction through the E-region dynamo.

Total thyroidectomy for benign thyroid disease.

OBJECTIVES/HYPOTHESIS: The use of total thyroidectomy in thyroid cancer treatment is not unanimous, and it is even more controversial when this procedure is advocated for benign diseases. On the other hand, the complication risk may have an increase up to 20 times in repeat operations for recurrence. The objective of the study was to evaluate the use of total thyroidectomy in benign diseases, multinodular goiter, and Graves disease to justify the authors' preference. STUDY DESIGN: Retrospective study of use of total thyroidectomy in benign diseases. METHODS: Retrospective study of 1789 patients who underwent thyroidectomies from June 1990 to December 2000. Indication, extension of thyroidectomy, cancer incidence, and complications were analyzed. RESULTS: Total thyroidectomy was performed in 81.19% of 456 patients with nontoxic multinodular goiter, 93.93% of 33 with toxic multinodular goiter, 93.93% of 66 with recurrent multinodular goiter, and 49.18% of 122 with Graves disease. Thyroid cancer was found in 16.62%, 9.09%, 3.03% and 5.73% of patients, respectively. Transitory and permanent hypoparathyroidism, hematoma requiring surgical intervention, and transitory and permanent recurrent laryngeal nerve injury occurred in 12.27%, 1.61%, 0.26%, 1.88%, and 0.35% of the patients undergoing total thyroidectomy, respectively. Permanent complications of total thyroidectomy for nontoxic multinodular goiter and Graves disease were similar to nontotal thyroidectomy. Use of total thyroidectomy for nontoxic multinodular goiter increased from 53.33% of the patient to 81.19%, on average, with a concomitant increase of cancer diagnosis from 11.11% to 16,62%. The authors performed total thyroidectomy for all patients with Graves disease. CONCLUSION: Total thyroidectomy is the treatment of choice for multinodular goiter and thyroiditis, when there is bilateral gland involvement posterior to middle thyroid veins, and for Graves disease because it decreases the likelihood of future repeat operations for recurrent disease and thus the associated risks, when performed safely.