Spectrophotometric experiment on the Verera-11 and Venera-12 descent vehicles: Some results of the analysis of the spectrum of the daytime sky of Venus

The spectra of the daytime sky of Venus were recorded on the Venera-11 and Venera-12 descent vehicles at various altitudes above the planet's surface, within the interval of 4500 to 12,000 Angstroms. The angular distribution of the brightness of the scattered radiation was recorded and the ratio of water and carbon dioxide were studied, with respect to the cloud cover boundaries

Car Trip Generation Models in the Developing World: Data Issues and Spatial Transferability

In many countries of the developing world, it is difficult to conduct large-scale household travel surveys to collect data for travel behaviour model estimation and application. This paper focuses on two candidate solutions to the problem: 1) developing models that can be applied for prediction using secondary data collected for other purposes and include socio-demographic information but do not include transport specific information like the car and/or transit pass ownership (e.g. census, public health records, etc.) 2) 'borrowing' a model developed using data from a similar city within the same region. In the first approach, we investigate the feasibility of developing car trip generation models which imputes the car ownership variable with estimated car ownership propensities. The proposed framework is applied in two East African cities, Nairobi and Dar-es-Salaam. The estimation results indicate that for both cities the proposed approach outperforms the models that exclude the car ownership variable. In the second approach, we investigate the spatial transferability of the models developed in the first approach between the two cities to evaluate if it is justified to apply models from one developing country to another in the absence of local models. Results indicate that though some of the estimated parameters are not significantly different from each other between the two cities, statistical tests do not support direct transferability of all the models from Nairobi to Dar-es-Salaam or vice versa. However, interestingly, the simpler model (which excludes car-ownership) outperforms the model with imputed car ownership propensity in terms of transferability. These findings provide useful insights into the development of trip generation models. under data constraints which can practically be very useful for developing countries

Исследование применимости ДПФ-модулированного банка фильтров в системах со значительным усилением спектральных составляющих

The purpose of this article is to investigate the application of DFT-modulated filter bank in systems with significant spectral component amplification like hearing aid. There is a description of analysis / synthesis method based on short-time Fourier transform (STFT), which is used in most systems of speech information processing. It is shown that DFT-modulated filter bank is a generalization of STFT-method. In analysis / synthesis system based on DFT-modulated filter bank, the input signal is divided into subbands, passing through the analysis filter bank then each subband is amplified and the last step is to reconstruct the signal with synthesis filter bank. However, in digital systems with significant spectral component amplification, the resulting signal is distorted after reconstruction because of amplification factor difference in each subband. The article provides expressions for the distortion and the aliasing functions, allowing to estimate the distortion value, which appears in analysis / synthesis system of DFT-modulated filter bank. Efficient algorithms for calculating the distortion and the aliasing functions are also offered. In future it is planning to develop a procedure for optimizing the DFT-modulated filter bank based on the proposed efficient algorithms for calculating distortion and spectral aliasing in the filter bank.Целью работы является исследование применимости ДПФ-модулированного банка фильтров в системах, требующих значительного усиления спектральных составляющих, таких как слуховой аппарат. Приведено описание метода анализа / синтеза звукового сигнала на основе кратковременного преобразования Фурье (КВПФ), используемого в большинстве систем обработки речевой информации. Показано, что ДПФ-модулированный банк фильтров является обобщением метода обработки на основе КВПФ. В системе анализ / синтез на основе ДПФ-модулированного банка фильтров входной сигнал разделяется на субполосы, проходя через банк фильтров анализа, далее происходит усиление сигнала в каждой субполосе, конечным этапом является восстановление сигнала с помощью банка фильтров синтеза. Однако в цифровых системах со значительным усилением спектральных составляющих из-за разницы в коэффициентах усиления для каждой субполосы результирующий сигнал после восстановления имеет искажения. В работе приводятся выражения для функции искажений и функции спектрального наложения, позволяющие оценить величину искажений, возникающих в системе анализ / синтез ДПФ-модулированного банка фильтров. Также предложены эффективные алгоритмы расчета функции искажений и функции спектральных наложений. В дальнейшем планируется разработка процедуры оптимизации ДПФ-модулированного банка фильтров, основанной на предложенных эффективных алгоритмах расчета функций искажений и спектральных наложений банка фильтров

Emergence of SARS-CoV-2 Omicron lineages BA.4 and BA.5 in South Africa

Three lineages (BA.1, BA.2 and BA.3) of the SARS-CoV-2 Omicron variant of concern predominantly drove South Africa's fourth COVID-19 wave. We have now identified two new lineages, BA.4 and BA.5, responsible for a fifth wave of infections. The spike proteins of BA.4 and BA.5 are identical, and comparable to BA.2 except for the addition of 69-70del (present in the Alpha variant and the BA.1 lineage), L452R (present in the Delta variant), F486V and the wild type amino acid at Q493.The two lineages only differ outside of the spike region. The 69-70 deletion in spike allows these lineages to be identified by the proxy marker of S-gene target failure, on the background of variants not possessing this feature . BA.4 and BA.5 have rapidly replaced BA.2, reaching more than 50% of sequenced cases in South Africa by the first week of April 2022. Using a multinomial logistic regression model, we estimate growth advantages for BA.4 and BA.5 of 0.08 (95% CI: 0.08 - 0.09) and 0.10 (95% CI: 0.09 - 0.11) per day respectively over BA.2 in South Africa. The continued discovery of genetically diverse Omicron lineages points to the hypothesis that a discrete reservoir, such as human chronic infections and/or animal hosts, is potentially contributing to further evolution and dispersal of the virus