First direct observation of a torsional Alfvén oscillation at coronal heights

Context. Torsional Alfvén waves are promising candidates for the transport of energy across different layers of the solar atmosphere. They have been predicted theoretically for decades. Previous detections of Alfvén waves so far have however mostly relied on indirect signatures. Aims. We present the first direct observational evidence of a fully resolved torsional Alfvén oscillation of a large-scale structure occurring at coronal heights. Methods. We analysed IRIS imaging and spectral observation of a surge resulting from magnetic reconnection between active region prominence threads and surrounding magnetic field lines. Results. The IRIS spectral data provide clear evidence of an oscillation in the line-of-sight velocity with a 180° phase difference between the oscillation signatures at opposite edges of the surge flux tube. This together with an alternating tilt in the Si IV and Mg II k spectra across the flux tube and the trajectories traced by the individual threads of the surge material provide clear evidence of torsional oscillation of the flux tube. Conclusions. Our observation shows that magnetic reconnection leads to the generation of large-scale torsional Alfvén waves

Efficiency of traps in collecting selected Diptera families according to the used bait: Comparison of baits and mixtures in a field experiment

Traps made from PET bottles were used to assess the efficiency of four baits in terms of the number of individuals for selected Diptera families collecting in Eastern Slovak gardens in summer and autumn. Bait used in traps significantly affected the taxonomical composition of the samples obtained. Moreover, significant differences in bait efficiencies and temporal shift in bait efficiencies were confirmed for the Diptera order and for selected dipteran families. The most effective bait for baited-trap Diptera sampling was beer, followed by wine, meat, and syrup from the summer sampling season. In the autumn sampling season, the wine was most effective, followed by beer, syrup, and meat. For the family Scatopsidae wine, and for the family Platystomatidae, meat were the most effective baits. Drosophilidae were most attracted to beer in summer and to wine bait in autumn

Excitation of vertical coronal loop oscillations by impulsively driven flows

Context Flows of plasma along a coronal loop caused by the pressure difference between loop footpoints are common in the solar corona. Aims We aim to investigate the possibility of excitation of loop oscillations by an impulsively driven flow triggered by an enhanced pressure in one of the loop footpoints. Methods We carry out 2.5D magnetohydrodynamic (MHD) simulations of a coronal loop with an impulsively driven flow and investigate the properties and evolution of the resulting oscillatory motion of the loop. Results The action of the centrifugal force associated with plasma moving at high speeds along the curved axis of the loop is found to excite the fundamental harmonic of a vertically polarised kink mode. We analyse the dependence of the resulting oscillations on the speed and kinetic energy of the flow. Conclusions We find that flows with realistic speeds of less than 100 km s−1 are sufficient to excite oscillations with observable amplitudes. We therefore propose plasma flows as a possible excitation mechanism for observed transverse loop oscillations

THE SIGNIFICANT DETERMINANTS OF SUBSTANCE USE AMONG YOUNG PEOPLE FROM SECONDARY SCHOOL

The aim of the study was to identify both protective and risk factors for substance use among secondary school students. The research sample consisted of 726 secondary school students from Slovakia, aged from 11 to 19 years (431 girls, 295 boys). Within the framework of quantitatively oriented research, two areas have been monitored through the author’s questionnaire: Free time and emotions experienced in the family. The data was analysed through factor and regression analysis. To the basic results of the research belong the findings that the active spending of free time and the experiencing of positive emotions within the family are a protective factor in relation to substance use. The adolescents’ spending of free time with parents had no effect on substance use. Conversely, passive spending of free time was associated with a higher frequency of substance use

Excitation and evolution of vertically polarised transverse loop oscillations by coronal rain

Context. Coronal rain is composed of cool dense blobs that form in solar coronal loops and are a manifestation of catastrophic cooling linked to thermal instability. The nature and excitation of oscillations associated with coronal rain is not well understood. Aims. We consider observations of coronal rain in a bid to elucidate the excitation mechanism and evolution of wave characteristics. Methods. We analyse IRIS and Hinode/SOT observations of an oscillating coronal rain event on 17 Aug 2014 and determine the wave characteristics as a function of time using tried and tested time-space analysis techniques. Results. We exploit the seismological capability of the oscillation to deduce the relative rain mass from the oscillation amplitude. This is consistent with the evolution of the oscillation period showing the loop loosing a third of its mass due to falling coronal rain in a 10-15 minute time period. Conclusions. We present first evidence of the excitation of vertically polarised transverse loop oscillations triggered by a catastrophic cooling at the loop top and consistent with two thirds of the loop mass comprising of cool rain mass

Analysis of coronal rain observed by IRIS, HINODE/SOT and SDO/AIA : transverse oscillations, kinematics and thermal evolution

Coronal rain composed of cool plasma condensations falling from coronal heights along magnetic field lines is a phenomenon occurring mainly in active region coronal loops. Recent high resolution observations have shown that coronal rain is much more common than previously thought, suggesting its important role in the chromosphere-corona mass cycle. We present the analysis of MHD oscillations and kinematics of the coronal rain observed in chromospheric and transition region lines by IRIS, Hinode/SOT and SDO/AIA. Two different regimes of transverse oscillations traced by the rain are detected: small-scale persistent oscillations driven by a continuously operating process and localised large-scale oscillations excited by a transient mechanism. The plasma condensations are found to move with speeds ranging from few km s−1 up to 180 km s−1 and with accelerations largely below the free fall rate, with the likely reasons being pressure effects and the ponderomotive force resulting from the loop oscillations. The observed evolution of the emission in individual SDO/AIA bandpasses is found to exhibit clear signatures of a gradual cooling of the plasma at the loop top. We determine the temperature evolution of the coronal loop plasma using regularised inversion to recover the differential emission measure (DEM) and by forward modelling the emission intensities in the SDO/AIA bandpasses using a two-component synthetic DEM model. The inferred evolution of the temperature and density of the plasma near the apex is consistent with the limit cycle model and suggests the loop is going through a sequence of periodically repeating heating-condensation cycles

α1-Adrenoceptor agonist methoxaminen inhibits base excision repair via inhibition of apurinic/apyrimidinic endonuclease 1 (APE1)

Methoxamine (Mox) is a well-known α1-adrenoceptor agonist, clinically used as a longer-acting analogue of epinephrine. 1R,2S-Mox (NRL001) has been also undergoing clinical testing to increase the canal resting pressure in patients with bowel incontinence. Here we show, that Mox hydrochloride acts as an inhibitor of base excision repair (BER). The effect is mediated by the inhibition of apurinic/apyrimidinic endonuclease APE1. We link this observation to our previous report showing the biologically relevant effect of Mox on BER – prevention of converting oxidative DNA base damage to double-stranded breaks. We demonstrate that its effect is weaker, but still significant when compared to a known BER inhibitor methoxyamine (MX). We further determined Mox’s relative IC50 at 19 mmol L–1, demonstrating a significant effect of Mox on APE1 activity in clinically relevant concentrations

Populism in Old and New Democracies: Comparative Analysis of True Finns, Sweden Democrats, ANO and OĽaNO

The article aims to critically assess, through discourse analysis of their respective political programmes, the way populist parties in old and new democracies approach different questions in their societies. The representatives of the old democracies include the Sweden Democrats and the True Finns, while the new democracies are represented by the two Central Eastern European parties – the Czech ANO and the Slovak OĽaNO. The biggest contribution of this paper is the analysis of how these parties in their discourses approach the idea and definitions of the people (populus), the enemy, both as a cultural enemy and the establishment, in addition to critically dissecting their influence on liberal democracy (corrective or threat). The distinction between old and new democracies does not hold its ground anymore because the parties from new democracies are gradually following the same course set by the well-established populist parties, mainly in altering the perspective of the external enemy, currently depicted in immigration

Kinematics of coronal rain in a transversely oscillating loop : ponderomotive force and rain-excited oscillations

E.V. acknowledges support from the Warwick STFC Consolidated Grant ST/L000733/I. P.A. acknowledges support from the EU Horizon 2020 Research and Innovation programme (grant agreement No. 647214). P.K. acknowledges support from a UK STFC PhD studentship. T.N. acknowledges support from the St Andrews STFC Consolidated Grant SN/N000609/1.Context. Coronal rain are cool dense blobs that form in solar coronal loops and are a manifestation of catastrophic cooling linked to thermal instability. Once formed, rain falls towards the solar surface at sub-ballistic speeds, which is not well-understood. Pressure forces seem to be the prime candidate to explain this. In many observations rain is accompanied by transverse oscillations and the interaction between the two needs to be explored. Aims. Therefore, an alternative kinematic model for coronal rain kinematics in transversely oscillating loops is developed to understand the physical nature of the observed sub-ballistic falling motion of rain. It explicitly explores the role of the ponderomotive force arising from the transverse oscillation on the rain motion as well as the capacity of rain to excite wave motion. Methods. An analytical model is presented that describes a rain blob guided by the coronal magnetic field supporting a one dimensional shear Alfvén wave as a point mass on an oscillating string. The model includes gravity and the ponderomotive force from the oscillation acting on the mass, as well as the inertia of the mass acting on the oscillation. Results. The kinematics of rain in the limit of negligible rain mass are explored and falling and trapped regimes are found, depending on wave amplitude. In the trapped regime for the fundamental mode, the rain blob bounces back and forth around the loop top at a long period inversely proportional to the oscillation amplitude. The model is compared with several observational rain studies, including one in-depth comparison with an observation that shows rain with up-and down bobbing motion. The role of rain inertia in exciting transverse oscillations is explored in inclined loops. Conclusions. It is found that the model requires displacement amplitudes of the transverse oscillation that are typically an order of magnitude larger than observed to explain the measured sub-ballistic motion of the rain. Therefore, it is concluded that the ponderomotive force is not the primary reason for understanding sub-ballistic motion, but it plays a role in cases of large loop oscillations.The appearance of rain causes the excitation of small-amplitude transverse oscillations that may explain observed events and provide a seismological tool to measure rain mass.Publisher PDFPeer reviewe