Variabilidad de los parámetros de radiopropagación asociada a cambios diarios en la ionósfera sobre Concepción, Chile

Se estudia la variabilidad de la concentración electrónica de la ianósfera sobre Concepción, Chile, y su efecto en la variabilidad de parámetros de radiopropagación. Se compara las distribuciones verticales de concentración electrónica, derivadas mediante la técnica de inversión de ionogramas, para el mediodía de unos pocos días de Mano de 1964, y que fueran publicados hace algún tiempo, con aquellas determinadas usando los modelos da Dudeney y de Bradley y Dudeney. Se encuentra que las distribuciones calculadas con las fórmulas de Dudeney se ajustan mejor a las obtenidas mediante inversión. Se encuentra que la variabilidad diaria de las distribuciones verticales modaladadas para el mediodía de la mayoría de los días de mano de 1964 es prácticamente independiente del modelo usado. La variabilidad cambia desde un 20% para alturas de la región E hasta alrededor de un 70% a 240 km. Se analisa el efecto de esta variabilidad diaria sobre parámetros de radiopropagación, usando resultados obtenidos con la técnica de trasudo de rayos, para sedales de 7.1 y y 14.2 MHs emitidas desde Concepción hacia el Norte y Este, con una serie de ángulos de elevación. Se incluye el efecto da la absorción radioeléctrica y del campo magnético. Los gráficos de distancia alcansada versus ángulo de elevación construidos muestran que los resultados asociados a las distribuciones verticales de Dudeney se ajustan mejor a los resultados correspondientes a la inversión de ionogramas que aquellos asociados a las distribuciones de Bradley y Dudeney. Se encuentra una variabilidad diaria del 100% para señales de 7.1 MHs y de 80% para señalas de 14.2 MHs que se propagan en modo E. Las variabilidades para el modo F son menores, sólo un 25% para 7.1 MHs y ángulo de elevación da 50° y 15% para 14.2 MHs y 30°.Ionospheric electron concentration variability over Concepción, Chile, and its effect on the variability of radiopropagation parameters are studied. Published vertical distributions of electron concentration far a few day of March 1964 at noon, derived using the ionogram inversion technique, are compared with those determined from Dudeney and Bradley and Dudeney models. Distributions computed using Dudeney's formulae are found to systematically better fit those related ionogram inversion. Day-to-day variability derived using modal vertical distributions far most day of March 1964 at noon is found to be independent of the model considered. It ranges from about 20% at E region heights to 70% at around 240 km. The effect of this day-to-day variability an radiopropagation parameters was analysed using ny—tracing results for lignait of 7.1 MHi and 14.2 MHi launched from Concepción towards the North and Eact, for a range of elevation angler. Geomagnetic field and radiowave absorption effects were included. Plots of range vanus elevation angle show that results associated to Dudeney's vertical distributions better fit those associated to ionogram inversion, than th* anti associated to Bradley and Dudeney distributions. E—mode range day-to-day variability amounts 100% for 7.1 MHi and 80% for 14.2 MHi. F—mode variabilities are smaller, being 25% for MHt signals launched at 50° and 15s for 14.2 MHi signals at 30s.Asociación Argentina de Geofísicos y Geodesta

Upper atmosphere phenomena in Brazilian Geomagnetic Anomaly Region and their relationship to polar region disturbances

第2回極域科学シンポジウム/第35回極域宙空圏シンポジウム 11月16日（水） 統計数理研究所 3階リフレッシュフロ

GEANT4 : a simulation toolkit

Abstract Geant4 is a toolkit for simulating the passage of particles through matter. It includes a complete range of functionality including tracking, geometry, physics models and hits. The physics processes offered cover a comprehensive range, including electromagnetic, hadronic and optical processes, a large set of long-lived particles, materials and elements, over a wide energy range starting, in some cases, from 250 eV and extending in others to the TeV energy range. It has been designed and constructed to expose the physics models utilised, to handle complex geometries, and to enable its easy adaptation for optimal use in different sets of applications. The toolkit is the result of a worldwide collaboration of physicists and software engineers. It has been created exploiting software engineering and object-oriented technology and implemented in the C++ programming language. It has been used in applications in particle physics, nuclear physics, accelerator design, space engineering and medical physics. PACS: 07.05.Tp; 13; 2

Near real-time input to a propagation model for nowcasting of HF communications with aircraft on polar routes

There is a need for improved techniques for nowcasting and forecasting (over several hours) HF propagation at northerly latitudes to support airlines operating over the increasingly popular trans-polar routes. In this paper the assimilation of real-time measurements into a propagation model developed by the authors is described, including ionosonde measurements and Total Electron Content (TEC) measurements to define the main parameters of the ionosphere. The effects of D-region absorption in the polar cap and auroral regions are integrated with the model through satellite measurements of the flux of energetic solar protons (>1 MeV) and the X-ray flux in the 0.1-0.8 nm band, and ground-based magnetometer measurements which form the Kp and Dst indices of geomagnetic activity. The model incorporates various features (e.g. convecting patches of enhanced plasma density) of the polar ionosphere that are, in particular, responsible for off-great circle propagation and lead to propagation at times and frequencies not expected from on-great circle propagation alone. The model development is supported by the collection of HF propagation measurements over several paths within the polar cap, crossing the auroral oval, and along the mid-latitude trough

Induction chemotherapy followed by concurrent standard radiotherapy and daily low-dose cisplatin in locally advanced non-small-cell lung cancer

Both induction chemotherapy and concurrent low-dose cisplatin have been shown to improve results of thoracic irradiation in the treatment of locally advanced non-small-cell lung cancer (NSCLC). This phase II study was designed to investigate activity and feasibility of a novel chemoradiation regimen consisting of induction chemotherapy followed by standard radiotherapy and concurrent daily low-dose cisplatin. Previously untreated patients with histologically/cytologically proven unresectable stage IIIA/B NSCLC were eligible. Induction chemotherapy consisted of vinblastine 5 mg m−2 intravenously (i.v.) on days 1, 8, 15, 22 and 29, and cisplatin 100 mg m−2 i.v. on days 1 and 22 followed by continuous radiotherapy (60 Gy in 30 fractions) given concurrently with daily cisplatin at a dose of 5 mg m−2 i.v. Thirty-two patients were enrolled. Major toxicity during induction chemotherapy was haematological: grade III–IV leukopenia was observed in 31% and grade II anaemia in 16% of the patients. The most common severe toxicity during concurrent chemoradiation consisted of grade III leukopenia (21% of the patients); grade III oesophagitis occurred in only two patients and pulmonary toxicity in one patient who died of this complication. Eighteen of 32 patients (56%, 95% CI 38–73%) had a major response (11 partial response, seven complete response). With a median follow-up of 38.4 months, the median survival was 12.5 months and the actuarial survival rates at 1, 2 and 3 years were 52%, 26% and 19% respectively. The median event-free survival was 8.3 months with a probability of 40%, 23% and 20% at 1, 2 and 3 years respectively. Induction chemotherapy followed by concurrent daily low-dose cisplatin and thoracic irradiation, in patients with locally advanced NSCLC, is active and feasible with minimal non-haematological toxicity. Long-term survival results are promising and appear to be similar to those of more toxic chemoradiation regimens, warranting further testing of this novel chemoradiation strategy. © 1999 Cancer Research Campaig

Distinct effects of rectum delineation methods in 3D-confromal vs. IMRT treatment planning of prostate cancer

BACKGROUND: The dose distribution to the rectum, delineated as solid organ, rectal wall and rectal surface, in 3D conformal (3D-CRT) and intensity-modulated radiotherapy treatment (IMRT) planning for localized prostate cancer was evaluated. MATERIALS AND METHODS: In a retrospective planning study 3-field, 4-field and IMRT treatment plans were analyzed for ten patients with localized prostate cancer. The dose to the rectum was evaluated based on dose-volume histograms of 1) the entire rectal volume (DVH) 2) manually delineated rectal wall (DWH) 3) rectal wall with 3 mm wall thickness (DWH(3)) 4) and the rectal surface (DSH). The influence of the rectal filling and of the seminal vesicles' anatomy on these dose parameters was investigated. A literature review of the dose-volume relationship for late rectal toxicity was conducted. RESULTS: In 3D-CRT (3-field and 4-field) the dose parameters differed most in the mid-dose region: the DWH showed significantly lower doses to the rectum (8.7% ± 4.2%) compared to the DWH(3 )and the DSH. In IMRT the differences between dose parameters were larger in comparison with 3D-CRT. Differences were statistically significant between DVH and all other dose parameters and between DWH and DSH. Mean doses were increased by 23.6% ± 8.7% in the DSH compared to the DVH in the mid-dose region. Furthermore, both the rectal filling and the anatomy of the seminal vesicles influenced the relationship between the dose parameters: a significant correlation of the difference between DVH and DWH and the rectal volume was seen in IMRT treatment. DISCUSSION: The method of delineating the rectum significantly influenced the dose representation in the dose-volume histogram. This effect was pronounced in IMRT treatment planning compared to 3D-CRT. For integration of dose-volume parameters from the literature into clinical practice these results have to be considered

Ionospheric response modeling under eclipse conditions: Evaluation of 14 December 2020, total solar eclipse prediction over the South American sector

In this work, we evaluate the SUPIM-INPE model prediction of the 14 December 2020, total solar eclipse over the South American continent. We compare the predictions with data from multiple instruments for monitoring the ionosphere and with different obscuration percentages (i.e., Jicamarca, 12.0°S, 76.8°W, 17%; Tucumán 26.9°S, 65.4° W, 49%; Chillán 36.6°S, 72.0°W; and Bahía Blanca, 38.7°S, 62.3°W, reach 95% obscuration) due to the eclipse. The analysis is done under total eclipse conditions and non-total eclipse conditions. Results obtained suggest that the model was able to reproduce with high accuracy both the daily variation and the eclipse impacts of E and F1 layers in the majority of the stations evaluated (except in Jicamarca station). The comparison at the F2 layer indicates small differences (<7.8%) between the predictions and observations at all stations during the eclipse periods. Additionally, statistical metrics reinforce the conclusion of a good performance of the model. Predicted and calibrated Total Electron Content (TEC, using 3 different techniques) are also compared. Results show that, although none of the selected TEC calibration methods have a good agreement with the SUPIM-INPE prediction, they exhibit similar trends in most of the cases. We also analyze data from the Jicamarca Incoherent Scatter Radar (ISR), and Swarm-A and GOLD missions. The electron temperature changes observed in ISR and Swarm-A are underestimated by the prediction. Also, important changes in the O/N2 ratio due to the eclipse, have been observed with GOLD mission data. Thus, future versions of the SUPIM-INPE model for eclipse conditions should consider effects on thermospheric winds and changes in composition, specifically in the O/N2 ratio