Secondary Protons In The Atmosphere At Different Latitudes

We present a semiempirical method to study the production and propagation of atmospheric secondary protons with energy>100 Mev, moving in the vertical direction. The derived production functions are fitted by the least-square method for the only previously published splash (SP) and return (RE) albedos observed data using the same instrument and measurement sites. The closed agreements between the measurement data and the calculations over a wide range of atmospheric depths lead to a possible extension of the method for other latitudes. The spectra of SP and RE intensities versus the geomagnetic cut-off reveal similar behaviour as assumed earlier by the theory for those components in the Earth's magnetic field. © 1993 Società Italiana di Fisica.16217918

Atmospheric Cosmic Rays In The South Atlantic Anomaly Region

To study the production and propagation of fast secondaries particles in the atmosphere, data collected during eleven quiet-time balloon flights are analysed. Comparisons of these data with those obtained in different geomagnetic rigidity regions permit to estimate the contributions of the proton and electron components in the measured intensities. Derivations of this last component in the «upward» and «downward» moving electrons fluxes indicate that in the anomaly region a fraction of these particles, produced by the primary protons, are leaving the atmosphere and will not return to the Earth. © 1991 Società Italiana di Fisica.14214515

Electron Measurements In The Lower Atmosphere Near The South-atlantic Magnetic Anomaly

To investigate the variation of the flux of cosmic radiation in the vicinity of the earth, stratospheric balloon soundings are performed weekly at Campinas (Brazil). During some soundings, enhancements of the counting rates are detected. In this article data from these excesses as well as their analysis are shown. The integral flux, estimated from extrapolation of these data to the top of the atmosphere, is in good agreement with satellite measurements and seems to indicate that possibly high-energy electrons are injected from the lower boundary of the radiation belt into the stratosphere. © 1989.2802-3419423Hess, (1972) The Radiation Belt and Magnetosphere, , Atomizdat, MoscowVernov, (1964) Izv. Akad. Nauk SSSR, 28, N2, p. 2058. , Ser. FizN.L. Grigorov, L.V. Kurnosova, L.A. Razorenov, and M.I. Fradkin, Preprint 219 (P.N. Lebedev Phys. Inst. of the Acad. of Sci., Moscow, 1987)Galper, Gratchev, Dimitrenko, Kirillov-Ugryumov, Poluhina, Ulin, 18th Int. Cosmic Ray Conf. (1983) 1983 Conf. Papers MG Sessions, 3, p. 497. , Bangalore, 3rd edCharakhchaynm, Bazilevskaya, Stozkhov, Charackchyam, (1976) Trudy Fiz. Inst. Akad. Nauk SSSR, 88, p. 3Charakhchyan, Bazilevskaya, Stozhkov, Charackchyan, 16th Int. Cosmic Ray Conf. (1979) Conf. Papers MG Sessions, 3, p. 227. , Kyoto, 1979, 3rd edAsatryan, Stozhkov, 18th Int. Cosmic Ray Conf. (1983) Conf. Papers MG Sessions, 3, p. 299. , Bangalore, 1983, 3rd edBazilevskaya, Makhmutov, Charackhchyan, 19th Int. Cosmic Ray Conf. (1985) Conf. Papers SH Sessions, 5, p. 363. , La Jolla, 1985, 3rd e

Time Fluctuations Of Charged And Neutral Cosmic-ray Component Fluxes As Measured In The Region Of The Brazilian Magnetic Anomaly

Measurements of charged particles, gamma emission and neutrons were fulfilled on balloon in the region of the Brazilian magnetic anomaly on 8 November 1991. The flight lasted approximately 18 hours, including 15 hours on the ceiling at the height of 32 km just during the beginning of the recovery phase of the moderate geomagnetic storm. The main conclusion from the analysis of the obtained experimental data is the following:a) the fluxes of charged and neutral particles were measured and are in agreement with the data of previous works for the close values of geomagnetic cut-off rigidity;b) no sporadic increases of charged- and neutral-particle fluxes were recorded;c) the pulsations of charged particles, gamma-rays and neutrons with characteristic time of ≈ 30 min were found. The sporadic pulsations of charged particles and gamma-rays with shorter periods were observed too. But later pulsations were absent in the neutron flux data. This points to the magnetospheric origin of the observed phenomenon. © 1994 Società Italiana di Fisica.17222323

Combined characterisation of GOME and TOMS total ozone measurements from space using ground-based observations from the NDSC

Several years of total ozone measured from space by the ERS-2 GOME, the Earth Probe TOMS, and the ADEOS TOMS, are compared with high-quality ground-based observations associated with the Network for the Detection of Stratospheric Change (NDSC), over an extended latitude range and a variety of geophysical conditions. The comparisons with each spaceborne sensor are combined altogether for investigating their respective solar zenith angle (SZA) dependence, dispersion, and difference of sensitivity. The space- and ground-based data are found to agree within a few percent on average. However, the analysis highlights for both GOME and TOMS several sources of discrepancies: (i) a SZA dependence with TOMS beyond 80° SZA; (ii) a seasonal SZA dependence with GOME beyond 70° SZA; (iii) a difference of sensitivity with GOME at high latitudes; (iv) a difference of sensitivity to low ozone values between satellite and SAOZ sensors around the southern tropics; (v) a north/south difference of TOMS with the ground-based observations; and (vi) internal inconsistencies in GOME total ozon

Predicting outcomes of pelvic exenteration using machine learning

Aim: We aim to compare machine learning with neural network performance in predicting R0 resection (R0), length of stay > 14 days (LOS), major complication rates at 30 days postoperatively (COMP) and survival greater than 1 year (SURV) for patients having pelvic exenteration for locally advanced and recurrent rectal cancer. Method: A deep learning computer was built and the programming environment was established. The PelvEx Collaborative database was used which contains anonymized data on patients who underwent pelvic exenteration for locally advanced or locally recurrent colorectal cancer between 2004 and 2014. Logistic regression, a support vector machine and an artificial neural network (ANN) were trained. Twenty per cent of the data were used as a test set for calculating prediction accuracy for R0, LOS, COMP and SURV. Model performance was measured by plotting receiver operating characteristic (ROC) curves and calculating the area under the ROC curve (AUROC). Results: Machine learning models and ANNs were trained on 1147 cases. The AUROC for all outcome predictions ranged from 0.608 to 0.793 indicating modest to moderate predictive ability. The models performed best at predicting LOS > 14 days with an AUROC of 0.793 using preoperative and operative data. Visualized logistic regression model weights indicate a varying impact of variables on the outcome in question. Conclusion: This paper highlights the potential for predictive modelling of large international databases. Current data allow moderate predictive ability of both complex ANNs and more classic methods

Mortality from esophagectomy for esophageal cancer across low, middle, and high-income countries: An international cohort study.

BACKGROUND No evidence currently exists characterising global outcomes following major cancer surgery, including esophageal cancer. Therefore, this study aimed to characterise impact of high income countries (HIC) versus low and middle income countries (LMIC) on the outcomes following esophagectomy for esophageal cancer. METHOD This international multi-center prospective study across 137 hospitals in 41 countries included patients who underwent an esophagectomy for esophageal cancer, with 90-day follow-up. The main explanatory variable was country income, defined according to the World Bank Data classification. The primary outcome was 90-day postoperative mortality, and secondary outcomes were composite leaks (anastomotic leak or conduit necrosis) and major complications (Clavien-Dindo Grade III - V). Multivariable generalized estimating equation models were used to produce adjusted odds ratios (ORs) and 95% confidence intervals (CI). RESULTS Between April 2018 to December 2018, 2247 patients were included. Patients from HIC were more significantly older, with higher ASA grade, and more advanced tumors. Patients from LMIC had almost three-fold increase in 90-day mortality, compared to HIC (9.4% vs 3.7%, p < 0.001). On adjusted analysis, LMIC were independently associated with higher 90-day mortality (OR: 2.31, CI: 1.17-4.55, p = 0.015). However, LMIC were not independently associated with higher rates of anastomotic leaks (OR: 1.06, CI: 0.57-1.99, p = 0.9) or major complications (OR: 0.85, CI: 0.54-1.32, p = 0.5), compared to HIC. CONCLUSION Resections in LMIC were independently associated with higher 90-day postoperative mortality, likely reflecting a failure to rescue of these patients following esophagectomy, despite similar composite anastomotic leaks and major complication rates to HIC. These findings warrant further research, to identify potential issues and solutions to improve global outcomes following esophagectomy for cancer