Results 1 to 10 of about 9,731 (202)

Continuous Doppler sounding of the ionosphere during solar flares [PDF]

Earth, Planets and Space, 2018
Solar flares cause a rapid increase in ionization in the ionosphere owing to significant enhancement of ionizing solar radiation in the X-ray and extreme ultraviolet (EUV) spectral ranges. The change of electron densities in the ionosphere influences the
Jaroslav Chum, Jaroslav Urbář, Jan Laštovička, Miguel Angel Cabrera, Jann-Yenq Liu, Fernando Alberto Miranda Bonomi, Mariano Fagre, Jiří Fišer, Zbyšek Mošna   +8 more
doaj   +7 more sources

Propagation of gravity waves and spread F in the low‐latitude ionosphere over Tucumán, Argentina, by continuous Doppler sounding: First results [PDF]

Journal of Geophysical Research: Space Physics, 2014
AbstractResults of systematic analysis of propagation directions and horizontal velocities of gravity waves (GWs) and spread F structures in low‐latitude ionosphere (magnetic inclination ~27°) in Tucumán region, Argentina, are presented. Measurements were carried out by multipoint continuous Doppler system during 1 year from December 2012 to November ...
Chum, J., Miranda Bonomi, Fernando Alberto, Fišer, J., Cabrera, M. A., Ezquer, Rodolfo Gerardo, Burešová, D., Laštovička, J., Baše, J., Hruška, F., Molina, Maria Graciela, Ise, Juan Eduardo, Cangemi, José Ignacio, Šindelářová, T.   +12 more
openaire   +6 more sources

Doppler Spectrum Measurement Platform for Narrowband V2V Channels

IEEE Access, 2022
This paper describes the implementation of a Doppler spectrum measurement platform for narrowband frequency-dispersive vehicle-to-vehicle (V2V) channels.
Carlos A. Gomez-Vega, Jorge Cardenas, Juan C. Ornelas-Lizcano, Carlos A. Gutierrez, Marco Cardenas-Juarez, Jose M. Luna-Rivera, Ruth M. Aguilar-Ponce   +6 more
doaj   +1 more source

Multi-instrumental detection of a fireball during Leonids of 2019

Frontiers in Astronomy and Space Sciences, 2023
During the 2019 Leonid meteor shower, the European Fireball Network recorded a bright fireball (meteor code: EN171119_041459) at 04:15:0.2 (UT) on 17 November 2019.
Cs. Szárnya, Cs. Szárnya, J. Chum, K. Podolská, D. Kouba, P. Koucká Knížová, Z. Mošna, V. Barta   +7 more
doaj   +1 more source

Heart Sounds Obtained With Noncontact Continuous-Wave Echo Doppler

Computing in Cardiology Conference (CinC), 2018
Heart sounds can be obtained in various ways. A recent modality is airborne ultrasound echo Doppler, which has been used either in a pulsed wave mode or a continuous wave mode. In the present work we analyse the continuous wave ultrasound echo from the chest. In 10 subjects a piezo ultrasound transceiver was used to transmit a 40 kHz acoustic sine wave
Struijk, Johannes Jan; id_orcid 0000-0002-8713-1913, Eiriksdóttir, Dagbjört Helga, Pálsdóttir, Ásgerdur Arna; id_orcid 0000-0002-1659-8567, Schmidt, Samuel Emil; id_orcid 0000-0002-0917-634X   +3 more
  +5 more sources

Evidence of vertical coupling: meteorological storm Fabienne on 23 September 2018 and its related effects observed up to the ionosphere [PDF]

Annales Geophysicae, 2020
A severe meteorological storm system on the frontal border of cyclone Fabienne passing above central Europe was observed on 23–24 September 2018. Large meteorological systems are considered to be important sources of the wave-like variability visible ...
P. Koucká Knížová, K. Podolská, K. Potužníková, D. Kouba, Z. Mošna, J. Boška, M. Kozubek   +6 more
doaj   +1 more source

Statistical investigation of gravity wave characteristics in the ionosphere

Earth, Planets and Space, 2021
Propagation of medium-scale gravity waves (GWs) in the thermosphere/ionosphere is observed remotely, using multi-frequency and multi-point continuous Doppler sounding system located in the western part of Czechia. Reflection heights of the sounding radio
Jaroslav Chum, Kateřina Podolská, Jan Rusz, Jiří Baše, Nikolai Tedoradze   +4 more
doaj   +1 more source

Detection of suspended macroplastics using acoustic doppler current profiler (ADCP) echo

Frontiers in Earth Science, 2023
Plastic pollution has become an enormous environmental problem, endangering ecosystems, livelihoods, safety and human health. Large quantities of plastics are trapped in or transported by rivers.
Anouk Boon, Frans A. Buschman, Tim H. M. van Emmerik, Sophie Broere, Bart Vermeulen   +4 more
doaj   +1 more source

Acute hypoxia diminishes the relationship between blood pressure and subarachnoid space width oscillations at the human cardiac frequency. [PDF]

PLoS ONE, 2017
BACKGROUND:Acute hypoxia exerts strong effects on the cardiovascular system. Heart-generated pulsatile cerebrospinal fluid motion is recognised as a key factor ensuring brain homeostasis.
Magdalena Wszedybyl-Winklewska, Jacek Wolf, Ewa Swierblewska, Katarzyna Kunicka, Agnieszka Gruszecka, Marcin Gruszecki, Wieslawa Kucharska, Pawel J Winklewski, Joanna Zabulewicz, Wojciech Guminski, Michal Pietrewicz, Andrzej F Frydrychowski, Leszek Bieniaszewski, Krzysztof Narkiewicz   +13 more
doaj   +1 more source

Parameters of traveling ionospheric disturbances: results from spaced oblique HF sounding

Вісник Харківського національногоуніверситету імені В.Н. Каразіна. Серія: Радіофізика та електроніка, 2022
Urgency. A characteristic feature of the ionospheric radio channel is that its parameters depend on season, local time, solar activity, geographic coordinates, the state of the sun, the state of atmospheric-space weather, etc. The state of the atmosphere
L. F. Chernogor, K. P. Garmash, Q. Guo, Y. H. Zhdanko, V. F. Pushin, A. M. Tsymbal, Yu. Zheng   +6 more
doaj   +1 more source