Blanket Restrictive Measures in the Czech Republic During the COVID-19 Pandemic – A Trade-Off Concept Application

In early 2020, many widespread restrictive measures were introduced worldwide in response to the COVID-19 pandemic. These measures entailed high socio-economic costs, which have been largely overlooked due to political motivations and the difficulty of their measurement. One of them is the negative impact of widespread restrictive measures on life expectancy due to the limited school attendance and the negative impact of restrictions on the population's health status. In this paper, we use our own structural model based on the trade-off analysis method. The research compares the lost years of life in the situation of the existence of restrictive measures and, on the contrary, the situation of a complete absence of these measures. We use data from the Czech Republic between February 2020 and October 2021. Our article concludes that the number of lost years of life is many times higher when widespread restrictive measures are implemented in all considered scenarios. These findings should be considered when making further decisions on applying widespread restrictive measures in the Czech Republic

Analyza svetelnych krivek slabych meteoru.

Available from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi

Recent meteor showers - models and observations

International audienceA number of meteor shower outbursts and storms occurred in recent years starting with several Leonid storms around 2000 [1]. The methods of modeling meteoroid streams became better and more precise. An increasing number of observing systems enabled better coverage of such events. The observers provide modelers with an important feedback on precision of their models. Here we present comparison of several observational results with the model predictions

Recent meteor showers - models and observations

International audienceA number of meteor shower outbursts and storms occurred in recent years starting with several Leonid storms around 2000 [1]. The methods of modeling meteoroid streams became better and more precise. An increasing number of observing systems enabled better coverage of such events. The observers provide modelers with an important feedback on precision of their models. Here we present comparison of several observational results with the model predictions

Ejection velocities, age, and formation process of SPE meteoroid cluster

Context. Meteoroid clusters represent a unique opportunity to study processes of meteoroid disruptions in interplanetary space. We follow our previous work about the September epsilon Perseid (SPE) meteoroid cluster from 2016 with a detailed analysis of the observed data and cluster formation conditions. Aims. Our goal is to determine ejection velocities of the cluster members and SPE’s age, as well as to estimate the most probable formation process. Methods. We precisely determined mutual positions and masses of all meteoroids including the errors. We assumed that the massdominated meteoroid is the parent body of the cluster and that the observed positions of meteoroids are controlled by the ejection velocities and the action of solar radiation pressure. A formula for the dependence of meteoroid ejection velocities on the mutual positions, masses, and cluster age was derived. It was assumed that the time at which the initial kinetic energy of all meteoroids reached a minimum value corresponds to the age of the cluster. Knowing values and directions of ejection velocities together with meteoroid masses then allowed us to determine the most likely process of cluster formation. Results. The meteoroids occupy a volume of 66 × 67 × 50 km and are shifted in the antisolar direction by 27 km relative to the parent meteoroid. The age of the cluster is 2.28 ± 0.44 days. The ejection velocities range from 0.13 ± 0.05 m s−1 to 0.77 ± 0.34 m s−1 with a mean value of 0.35 m s−1. The ejection velocity directions are inside the cone with an apex angle of 101 ± 5°. The axis of the cone is ~45° away from the solar direction and ~34° away from the mean direction of the flux of small meteoroids’ incident on the parent meteoroid. Formation due to the separation of part of the surface due to very fast rotation is the least likely thing to occur. We estimate the rotation frequency to be about 2 Hz and the corresponding stress is several orders of magnitude lower than the predicted strength limit. It is also difficult to explain the formation of the cluster by an impact of a small meteoroid on the parent body. However, this possibility, although not very likely, cannot be completely ruled out. The most probable process is the exfoliation due to thermal stresses. Their estimated magnitude is sufficient and the derived ejection velocities are consistent with this process of formation

Double-Station Automatic Video Observation of the Meteors

The double station observation of the meteors by means of sensitive image intensifier technique started at the Ondrejov Observatory 10 years ago. The sensitivity of such instrumentation allows detection of the meteors down to masses of fractions of gram. Moreover, video technique provides us with a time resolution of the meteor events. On the other side, the precision of the video data is lower in comparison with the photographic data. We are introducing technological progress on the project—replacing of the S-VHS camcorders with gigabite, ethernet cameras and making the whole process of video observation automatic

Long-Term Continuous Double Station Observation of Faint Meteor Showers

Meteor detection and analysis is an essential topic in the field of astronomy. In this paper, a high-sensitivity and high-time-resolution imaging device for the detection of faint meteoric events is presented. The instrument is based on a fast CCD camera and an image intensifier. Two such instruments form a double-station observation network. The MAIA (Meteor Automatic Imager and Analyzer) system has been in continuous operation since 2013 and has successfully captured hundreds of meteors belonging to different meteor showers, as well as sporadic meteors. A data processing pipeline for the efficient processing and evaluation of the massive amount of video sequences is also introduced in this paper