Interferometric imaging of the type IIIb and U radio bursts observed with LOFAR on 22 August 2017

Context. The Sun is the source of different types of radio bursts that are associated with solar flares, for example. Among the most frequently observed phenomena are type III solar bursts. Their radio images at low frequencies (below 100 MHz) are relatively poorly studied due to the limitations of legacy radio telescopes. Aims. We study the general characteristics of types IIIb and U with stria structure solar radio bursts in the frequency range of 20-80 MHz, in particular the source size and evolution in different altitudes, as well as the velocity and energy of electron beams responsible for their generation. Methods. In this work types IIIb and U with stria structure radio bursts are analyzed using data from the LOFAR telescope including dynamic spectra and imaging observations, as well as data taken in the X-ray range (GOES and RHESSI satellites) and in the extreme ultraviolet (SDO satellite). Results. In this study we determined the source size limited by the actual shape of the contour at particular frequencies of type IIIb and U solar bursts in a relatively wide frequency band from 20 to 80 MHz. Two of the bursts seem to appear at roughly the same place in the studied active region and their source sizes are similar. It is different in the case of another burst, which seems to be related to another part of the magnetic field structure in this active region. The velocities of the electron beams responsible for the generation of the three bursts studied here were also found to be different

Interferometric imaging of the type IIIb and U radio bursts observed with LOFAR on 22 August 2017

Context. The Sun is the source of different types of radio bursts that are associated with solar flares, for example. Among the most frequently observed phenomena are type III solar bursts. Their radio images at low frequencies (below 100 MHz) are relatively poorly studied due to the limitations of legacy radio telescopes.Aims. We study the general characteristics of types IIIb and U with stria structure solar radio bursts in the frequency range of 20-80 MHz, in particular the source size and evolution in different altitudes, as well as the velocity and energy of electron beams responsible for their generation.Methods. In this work types IIIb and U with stria structure radio bursts are analyzed using data from the LOFAR telescope including dynamic spectra and imaging observations, as well as data taken in the X-ray range (GOES and RHESSI satellites) and in the extreme ultraviolet (SDO satellite).Results. In this study we determined the source size limited by the actual shape of the contour at particular frequencies of type IIIb and U solar bursts in a relatively wide frequency band from 20 to 80 MHz. Two of the bursts seem to appear at roughly the same place in the studied active region and their source sizes are similar. It is different in the case of another burst, which seems to be related to another part of the magnetic field structure in this active region. The velocities of the electron beams responsible for the generation of the three bursts studied here were also found to be different.Peer reviewe

A Retrospective Study on the Risk of Respiratory Distress Syndrome in Singleton Pregnancies with Preterm Premature Rupture of Membranes between 24+0 and 36+6 Weeks, Using Regression Analysis for Various Factors

Aim. This study aimed to investigate the cause of respiratory distress syndrome (RDS) in neonates from singleton pregnancies with preterm premature rupture of membranes (pPROM) between 24+0 and 36+6 weeks by using regression analysis for various factors. Methods. In 175 singleton pregnancies with pPROM, 95 cases of RDS (54,29%) were diagnosed. In all cases the following information was collected: latency period of PROM, gestational age at birth, Umbilical Artery Pulsatility Index (UA PI), Middle Cerebral Artery Pulsatility Index (MCA PI), fetal distress, antenatal steroids use, delivery type, pregnancy hypertension disease, gestational glucose intolerance or diabetes, neonatal laboratory parameters, gender, weight, Apgar score, and other neonatal complications. Logistic regression analysis was used to investigate the effect of variables on RDS. Results. The results of logistic regression analysis showed that the following variables are closely correlated with RDS: female gender (OR=0.52; 95%CI:0.28-0,97), antenatal steroids use (OR=0,46; 95%CI:0,34-0,64), abnormal UA PI and MCA PI (OR=2.96; 95%CI:1,43-6,12) (OR=2.05; 95%CI:1,07-3,95), fetal distress (OR=2.33; 95%CI:1,16-4,71), maternal HGB (OR=0.69; 95%CI:0,5-0,96), and neonatal RBC, HGB (OR=0.32; 95%CI:0,19-0,55) (OR=0.75; 95%CI:0,65-0,88). Conclusions. The main RDS risk factors in premature neonates are gender, abnormal fetoplacental circulation, and fetal distress. The laboratory parameters such as lower RBC and HGB count are observed in infants with RDS