Very-high-frequency oscillations in the main peak of a magnetar giant flare.

Magnetars are strongly magnetized, isolated neutron stars1-3 with magnetic fields up to around 1015 gauss, luminosities of approximately 1031-1036 ergs per second and rotation periods of about 0.3-12.0 s. Very energetic giant flares from galactic magnetars (peak luminosities of 1044-1047 ergs per second, lasting approximately 0.1 s) have been detected in hard X-rays and soft γ-rays4, and only one has been detected from outside our galaxy5. During such giant flares, quasi-periodic oscillations (QPOs) with low (less than 150 hertz) and high (greater than 500 hertz) frequencies have been observed6-9, but their statistical significance has been questioned10. High-frequency QPOs have been seen only during the tail phase of the flare9. Here we report the observation of two broad QPOs at approximately 2,132 hertz and 4,250 hertz in the main peak of a giant γ-ray flare11 in the direction of the NGC 253 galaxy12-17, disappearing after 3.5 milliseconds. The flare was detected on 15 April 2020 by the Atmosphere-Space Interactions Monitor instrument18,19 aboard the International Space Station, which was the only instrument that recorded the main burst phase (0.8-3.2 milliseconds) in the full energy range (50 × 103 to 40 × 106 electronvolts) without suffering from saturation effects such as deadtime and pile-up. Along with sudden spectral variations, these extremely high-frequency oscillations in the burst peak are a crucial component that will aid our understanding of magnetar giant flares.

Gamma Ray Glow Observations at 20-km Altitude.

In the spring of 2017 an ER-2 aircraft campaign was undertaken over continental United States to observe energetic radiation from thunderstorms and lightning. The payload consisted of a suite of instruments designed to detect optical signals, electric fields, and gamma rays from lightning. Starting from Georgia, USA, 16 flights were performed, for a total of about 70 flight hours at a cruise altitude of 20 km. Of these, 45 flight hours were over thunderstorm regions. An analysis of two gamma ray glow events that were observed over Colorado at 21:47 UT on 8 May 2017 is presented. We explore the charge structure of the cloud system, as well as possible mechanisms that can produce the gamma ray glows. The thundercloud system we passed during the gamma ray glow observation had strong convection in the core of the cloud system. Electric field measurements combined with radar and radio measurements suggest an inverted charge structure, with an upper negative charge layer and a lower positive charge layer. Based on modeling results, we were not able to unambiguously determine the production mechanism. Possible mechanisms are either an enhancement of cosmic background locally (above or below 20 km) by an electric field below the local threshold or an enhancement of the cosmic background inside the cloud but then with normal polarity and an electric field well above the Relativistic Runaway Electron Avalanche threshold.

[The achievements and outlook in the control of helminthiases in Bulgaria]. / Dostizheniia i perspektivy bor'by s gel'mintozami v Bolgarii.

The paper describes organization and achievements of the struggle against human helminthiases over a 30-year period in Bulgaria. Over this period, in Bulgaria Taenia solium was eradicated, while the incidence of taeniasis, ascariasis, trichocephaliasis, hymenolepiasis, enterobiasis and ascariasis, trichocephaliasis, hymenolepiasis, enterobiasis and echinococcosis was reduced several-fold. The authors suggest effective measures for the struggle against other helminthiases in the following 5-10 years.

[Pancreatoscanography with 75Se-methionine following glucose loading]. / Pankreatoskanografiia s 75Se-metioninom posle sakharnoi nagruzki.

Altogether 110 patients with different pancreatic diseases were examined on the Picker magna-scanner 500 I (USA) with 75Se-methionine (9.2 MBq). Glucose load at a dose of 0.33 g/kg is recommended 50 min before examination increasing RP accumulation in the pancreas parenchyma and improving scanographic image. It is pointed out that the coincidence of scanographic and pathohistological diagnoses in pancreas cancer is noted in 62.5%, in cystic formations in 89%, and in chronic pancreatitis in 93% cases.

[Diagnostic and therapeutic measures in thyroid cancer]. / Diagnosticheskii i lechebnyi kompleks, primeniaemyi u bol'nykh s rakom shchitovidnoi zhelezy.

Sixty-one patients were admitted for treatment with suspicion of thyroid cancer. Multimodality diagnosis and therapy were used including a medical history, general and local status, laboratory findings, x-ray examination of the lungs and bones, radioisotope and radioimmunological in vivo and in vitro tests, thyroid resection, rapid histological examination, total strumectomy, curietherapy using 131I and substituting hormonotherapy with the dry thyroid extract. The feasibility of the scannographic method in early diagnosis and detection of thyroid cancer or rejected suspicion of recurrence of metastases is emphasized. It is indicated in rapid histological examination that determines the volume of surgical intervention. 131I therapy with the activity of 185-370 is sufficient for a complete ablation of the thyroid residue and the prevention of recurrence or metastatic appearance in other organs irrespective of a histological type of carcinoma. The patients were followed up for 5 years.