Frequency shifts in gravitational resonance spectroscopy

Quantum states of ultracold neutrons in the gravitational field are to be characterized through gravitational resonance spectroscopy. This paper discusses systematic effects that appear in the spectroscopic measurements. The discussed frequency shifts, which we call Stern-Gerlach shift, interference shift, and spectator state shift, appear in conceivable measurement schemes and have general importance. These shifts have to be taken into account in precision experiments

A spectroscopy approach to measure the gravitational mass of antihydrogen

We study a method to induce resonant transitions between antihydrogen ($\bar{H}$) quantum states above a material surface in the gravitational field of the Earth. The method consists of applying a gradient of magnetic field, which is temporally oscillating with the frequency equal to a frequency of transition between gravitational states of antihydrogen. A corresponding resonant change in the spatial density of antihydrogen atoms could be measured as a function of the frequency of applied field. We estimate an accuracy of measuring antihydrogen gravitational states spacing and show how a value of the gravitational mass of the $\bar{H}$ atom could be deduced from such a measurement. We also demonstrate that a method of induced transitions could be combined with a free-fall-time measurement in order to further improve the precision

Multi-mode quasi-periodic pulsations in a solar flare

Context. Quasi-periodic pulsations (QPP) of the electromagnetic radiation emitted in solar and stellar flares are often detected in microwave, white light, X-ray, and gamma-ray bands. Mechanisms for QPP are intensively debated in the literature. Previous studies revealed that QPP may manifest non-linear, non-stationary and, perhaps, multi-modal processes operating in flares. Aims. We study QPP of the microwave emission generated in an X3.2-class solar flare on 14 May, 2013, observed with the Nobeyama Radioheliograph (NoRH), aiming to reveal signatures of the non-linear, non-stationary, and multi-modal processes in the signal. Methods. The NoRH correlation signal obtained at the 17 GHz intensity has a clear QPP pattern. The signal was analysed with the Hilbert-Huang transform (HHT) that allows one to determine its instant amplitude and frequency, and their time variation. Results. It was established that the QPP consists of at least three well-defined intrinsic modes, with the mean periods of 15, 45, and 100 s. All the modes have quasi-harmonic behaviour with different modulation patterns. The 100 s intrinsic mode is a decaying oscillation, with the decay time of 250 s. The 15 s intrinsic mode shows a similar behaviour, with the decay time of 90 s. The 45 s mode has a wave-train behaviour. Conclusions. Dynamical properties of detected intrinsic modes indicate that the 100 s and 15 s modes are likely to be associated with fundamental kink and sausage modes of the flaring loop, respectively. The 100 s oscillation could also be caused by the fundamental longitudinal mode, while this interpretation requires the plasma temperature of about 30 million K and hence is not likely. The 45 s mode could be the second standing harmonics of the kink mode

Phraseology and institutional discourse: Angela Merkel

Linguosemiotic approach to the study of phraseological units used by an institutional language personality. The language personality of a politician, in particular Angela Merkel, is considered as an active mechanism for the functioning of institutional discours

The origin of quasi-periodicities during circular ribbon flares

Solar flares with a fan-spine magnetic topology can form circular ribbons. The previous study based on H\alpha line observations of the solar flares during March 05, 2014 by Xu et al. (2017) revealed uniform and continuous rotation of the magnetic fan-spine. Preliminary analysis of the flare time profiles revealed quasi-periodic pulsations (QPPs) with similar properties in hard X-rays, H\alpha, and microwaves. In this work, we address which process the observed periodicities are related to: periodic acceleration of electrons or plasma heating? QPPs are analysed in the H\alpha emission from the centre of the fan (inner ribbon R1), a circular ribbon (R2), a remote source (R3), and an elongated ribbon (R4) located between R2 and R3. The methods of correlation, Fourier, wavelet, and empirical mode decomposition are used. QPPs in H\alpha emission are compared with those in microwave and X-ray emission. We found multi-wavelength QPPs with periods around 150 s, 125 s, and 190 s. The 150-s period is seen to co-exist in H\alpha, hard X-rays, and microwave emissions, that allowed us to connect it with flare kernels R1 and R2. These kernels spatially coincide with the site of the primary flare energy release. The 125-s period is found in the H\alpha emission of the elongated ribbon R4 and the microwave emission at 5.7 GHz during the decay phase. The 190-s period is present in the emission during all flare phases in the H\alpha emission of both the remote source R3 and the elongated ribbon R4, in soft X-rays, and microwaves at 4--8 GHz. We connected the dominant 150-s QPPs with the slipping reconnection mechanism occurring in the fan. We suggested that the period of 125 s in the elongated ribbon can be caused by a kink oscillation of the outer spine connecting the primary reconnection site with the remote footpoint. The period of 190 s is associated with the 3-min sunspot oscillations.Comment: Accepted for publication in A&

The thylakoid carbonic anhydrase associated with photosystem II is the component of inorganic carbon accumulating system in cells of halo- and alkaliphilic cyanobacterium Rhabdoderma lineare

AbstractThe organization of carbonic anhydrase (CA) system in halo- and alkaliphilic cyanobacterium Rhabdoderma lineare was studied by Western blot analysis and immunocytochemical electron microscopy. The presence of putative extracellular α-CA of 60 kDa in the glycocalyx, forming a tight sheath around the cell, and of two intracellular β-CA is reported. We show for the first time that the β-CA of 60 kDa is expressed constitutively and associated with polypeptides of photosystem II (β-CA-PS II). Another soluble β-CA of 25 kDa was induced in low-bicarbonate medium. Induction of synthesis of the latter β-CA was accompanied by an increase in the intracellular pool of inorganic carbon, which suggests an important role of this enzyme in the functioning of a CO2-concentrating mechanism

Fast magnetoacoustic wave trains in magnetic funnels of the solar corona

Context: Fast magneto-acoustic waves are highly dispersive in waveguides, so they can generate quasi-periodic wave trains if a localised, impulsive driver is applied. Such wave trains have been observed in the solar corona and may be of use as a seismological tool since they depend upon the plasma structuring perpendicular to the direction of propagation. Aims. We extend existing models of magnetoacoustic waveguides to consider the effects of an expanding magnetic field. The funnel geometry employed includes a field-aligned density structure. Methods: We performed 2D numerical simulations of impulsively generated fast magneto-acoustic perturbations. The effects of the density contrast ratio, density stratification, and spectral profile of the driver upon the excited wave trains were investigated. Results: The density structure acts as a dispersive waveguide for fast magneto-acoustic waves and generates a quasi-periodic wave train similar to previous models. The funnel geometry leads to generating additional wave trains that propagate outside the density structure. These newly discovered wave trains are formed by the leakage of transverse perturbations, but they propagate upwards owing to the refraction caused by the magnetic funnel. Conclusions: The results of our funnel model may be applicable to wave trains observed propagating in the solar corona. They demonstrate similar properties to those found in our simulations

Effect of a chemical analogue of autoinducers of microbial anabiosis on the Ca2+ response of mycelial fungi

The microbial alkylhydroxybenzenes (AHB), autoinducers of anabiosis, or d1 factors, participate in stress response of mycelial fungi, as determined from changes in intracellular Ca2+ concentration. By using the genetically modified strain Aspergillus awamori 66A, which produces a recombinant Ca2+-dependent protein aequorin, the dynamics of Ca 2+ was studied in the cytosol of cells exposed to mechanical shock in the presence of the protective doses (0.001-0.01% w/vol) of a chemical AHB analogue, 4-n-hexylresorcinol. Like under stressful conditions, Ca2+ concentration increases in the cell cytosol in response to enhanced AHB level in a growing fungal culture; thus, AHB is perceived by cells as a stress signal. The level of cell response, which was determined from the amplitude of luminescence dependent on the Ca2+ concentration in cytosol was related to the physiological age of the cells and AHB concentration. Micromycete preincubation with AHB was found to protect cells from subsequent stress; this was reflected in the Ca2+ response. The protective AHB effect was manifested as (1) a significant decrease in the amplitude of luminescence and, thus, in Ca2+ accumulation in the cytosol during subsequent mechanical stress (as compared to the control-mechanical stress only); (2) development of the secondary Ca2+ response, which was not observed in the control; (3) a high level of Ca2+ retained in the cytosol for a long time in the presence of AHB (as compared to the control without preincubation with AHB). The mechanisms underlying the AHB effect on the Ca 2+ transport systems are discussed

Effect of a chemical analogue of autoinducers of microbial anabiosis on the Ca2+ response of mycelial fungi

The microbial alkylhydroxybenzenes (AHB), which are anabiosis autoinducers also termed d1 factors, participate in the stress response of mycelial fungi, as determined from changes in intracellular Ca2+ concentration. By using the genetically modified strain Aspergillus awamori 66A, which produces the recombinant Ca2+ -dependent protein aequorin, the dynamics of Ca2+ was studied in the cytosol of cells exposed to mechanical shock in the presence of protective doses (0.001-0.01% w/vol) of a chemical AHB analogue, 4-n-hexylre-sorcinol. As under stressful conditions, Ca2+ concentration increases in the cell cytosol in response to an enhanced AHB level in a growing fungal culture; thus, AHB is perceived by cells as a stress signal. The level of cell response, which was determined from the amplitude of luminescence dependent on the Ca2+ concentration in the cytosol, was related to the physiological age of the cells and the AHB concentration. Micromycete preincubation with AHB was found to protect cells from subsequent stress; this was reflected in the Ca2+ response. The protective AHB effect was manifested as (1) a significant decrease in the amplitude of luminescence and, thus, in Ca2+ accumulation in the cytosol during subsequent mechanical stress (as compared to the control-mechanical stress only); (2) development of a secondary Ca2+ response, which was not observed in the control; and (3) a high level of Ca 2+ retained in the cytosol for a long time in the presence of AHB (as compared to the control without preincubation with AHB). The mechanisms underlying the AHB effect on Ca2+ transport systems are discussed. © 2004 MAIK "Nauka/Interperiodica"