Abstract
We analyze properties of nonthermal radio emission from the Central Molecular Zone (CMZ) and from individual molecular clouds, and argue that the observed features can be interpreted in the ...framework of our recent theory of self-modulation of cosmic rays (CRs) penetrating dense molecular regions. For clouds with gas column densities of ∼10
23
cm
−2
, the theory predicts depletion of sub-GeV CR electrons, occurring due to self-modulation of CR protons and leading to harder synchrotron spectra in the sub-GHz range. The predicted imprints of electron depletion in the synchrotron spectra agree well with the spectral hardening seen in available radio observations of the CMZ. A similar, but even stronger, effect on the synchrotron emission is predicted for individual (denser) CMZ clouds, such as the Sgr B2. However, the emission at frequencies above ∼GHz, where observational data are available, is completely dominated by the thermal component, and therefore new observations at lower frequencies are needed to verify the predictions.
Abstract
We present a nonlinear model of a self-consistent Galactic halo, where the processes of cosmic-ray (CR) propagation and excitation/damping of MHD waves are included. The MHD turbulence that ...prevents CR escape from the Galaxy is entirely generated by the resonant streaming instability. The key mechanism controlling the halo size is the nonlinear Landau (NL) damping, which suppresses the amplitude of MHD fluctuations and, thus, makes the halo larger. The equilibrium turbulence spectrum is determined by a balance of CR excitation and NL damping, which sets the regions of diffusive and advective propagation of CRs. The boundary
z
cr
(
E
) between the two regions is the halo size, which slowly increases with the energy. For the vertical magnetic field of ∼1
μ
G, we estimate
z
cr
∼ 1 kpc for GeV protons. The derived proton spectrum is in a good agreement with observational data.
Aims
The objective of this work was to study the antibacterial specificity and antibacterial effect of endolysins isolated from colibacteriophages RB43, RB49 and T5—as manifested on the exponential ...and stationary cell cultures of diverse bacteria depending on the growth stage, structure of peptidoglycan (PG) and antibiotic resistance.
Methods and Results
Enzyme activity was assayed by the spectrophotometric method. Antimicrobial activity was estimated by the number of colony forming units (CFUs), with the results represented as logarithmic units. Morphological examination of bacterial cells was conducted using phase‐contrast and scanning electron microscopy. The enzymes EndoT5, endolysin of bacteriophage T5, EndoRB43, endolysin of bacteriophage RB43 and EndoRB49, endolysin of bacteriophage RB49 turned out to be much less bacteriospecific than the corresponding Escherichia coli phages; they lysed bacteria of the genera Bacillus, Cellulomonas and Sporosarcina, whose PGs had different structures (A1γ, A4α and A4β) and chemical modifications (amidation). The specific lytic activity of phage enzymes was independent of the antibiotic resistance of bacterial cells and was higher when the cells were in the exponential, rather than stationary, growth phase. The analysis of morphological changes showed that the intermediate stage of the endolysin‐induced lysis of bacterial cells was the formation of spheroplasts and protoplasts.
Conclusions
Endolysins of colibacteriophages RB49, RB43 and T5 have a wide spectrum of antibacterial action, which includes a number of diverse micro‐organisms with different PG structures.
Significance and Impact of the Study
This is a study of the bacterial selectivity of enzymes degrading bacterial cell wall in relation to the chemical structure of PG. It is shown that endolysins of bacteriophages RB49 and RB43 efficiently lyse cell wall of Gram‐positive bacteria of the genus Bacillus and Gram‐negative bacteria of the genus Pseudomonas (including an antibiotic‐resistant strain). The number of bacterial cells is reduced by 3–6 orders of magnitude, which indicates good prospects for using these enzymes in biotechnology.
A self-consistent model of a one-dimensional cosmic-ray (CR) halo around the Galactic disk is formulated with the restriction of a minimum number of free parameters. It is demonstrated that the ...turbulent cascade of MHD waves does not necessarily play an essential role in the halo formation. Instead, an increase of the Alfvén velocity with distance to the disk leads to an efficient generic mechanism of the turbulent redshift, enhancing CR scattering by the self-generated MHD waves. As a result, the calculated size of the CR halo at lower energies is determined by the halo sheath, an energy-dependent region around the disk beyond which the CR escape becomes purely advective. At sufficiently high energies, the halo size is set by the characteristic thickness of the ionized gas distribution. The calculated Galactic spectrum of protons shows a remarkable agreement with observations, reproducing the position of the spectral break at TeV and the spectral shape up to ∼10 TeV.
Screen shoes with three layout schemes of sieve arrangement were studied. There are separation and head screens installed in the upper tier in the first and third schemes, and in the lower one ...respectively there are two cleaning and two sorting screens, and in the latter between the tiers there is a rolling surface placed in the opposite direction of grain material movement. The second scheme involved the sequential installation of a sorting screen in the upper tier, and a cleaning and sorting screen in the lower tier. These schemes are used for preliminary, primary and secondary cleaning of grain material. The experimental studies made it possible to obtain the dependence graphs of the identified grain fractions on its supply to the beginning of the screen shoe, as well as the influence of grain supply on the quality indicators of winter wheat grain, such as the thousand-kernel weight of the main and forage fractions and the completeness of the fodder fraction extraction. The use of a screen shoe with a third layout scheme can provide seed cleaning with a supply of 0.38 kg/(s·m), commercial – with a supply of 1.05 kg/(s·m) and preliminary – with a supply of 3.94 kg/(s·m).
ABSTRACT We analyze the model of stochastic re-acceleration of electrons that are emitted by supernova remnants (SNRs) in the Galactic Disk and then propagate into the Galactic Halo in order to ...explain the origin of nonthermal (radio and gamma-ray) emission from Fermi bubbles (FB). We assume that the energy for re-acceleration in the Halo is supplied by shocks generated by processes of star accretion onto the central black hole. Numerical simulations show that regions with strong turbulence (places for electron re-acceleration) are located high up in the Galactic Halo several kpc above the disk. The energy of the SNR electrons that reach these regions does not exceed several GeV due to synchrotron and inverse Compton energy losses. At appropriate parameters of re-acceleration these electrons can be re-accelerated up to an energy of 1012 eV, which explains in this model the origin of the observed radio and gamma-ray emission from the FB. However, although the model gamma-ray spectrum is consistent with the Fermi results, the model radio spectrum is steeper than that observed by WMAP and Planck. If adiabatic losses due to plasma outflows from the Galactic central regions are taken into account, then the re-acceleration model nicely reproduces the Planck data points.
Background
Until now, there was no validated dermatology‐specific health‐related quality of life (HRQoL) instrument to be used in youngest patients.
Objective
To create dermatology‐specific proxy ...instrument for HRQoL assessment in children from birth to 4 years.
Methods
International focus groups, item selection and pilot tests were utilized. In order to avoid the problem of cross‐cultural inequivalence, focus group work and pilot tests were planned simultaneously in all national centres of the project. Comprehensibility, clarity, acceptance and internal consistency of new instrument were checked.
Results
The title ‘Infants and Toddlers Dermatology Quality of Life’ was chosen for our new instrument with the proposed acronym ‘InToDermQoL’. Focus group work was completed in seven national centres (Croatia, Germany, Greece, Malta, Poland, Romania and Ukraine). A total of 170 families of children with different skin diseases were interviewed, and a pilot version of the instrument was created. Centres from France, Denmark and Spain have joined the project at this stage. Parents of 125 children with skin diseases filled in the pilot versions of the instrument. Good comprehensibility, clarity, acceptance and internal consistency of the InToDermQoL were confirmed. The pilot test results showed that the InToDermQoL questionnaire well differentiates severity‐dependent differences. It was also checked and confirmed during the pilot test that no significant information was missed in the questionnaire. Three age‐specific versions of the InToDermQoL questionnaire with 10, 12 and 15 items, respectively, were approved for field tests.
Conclusion
The pilot test results showed that the InToDermQoL questionnaire has good comprehensibility, clarity, acceptance and internal consistency and well differentiates severity‐dependent differences. Further validation of the InToDermQoL during international field test will be performed.
We analyze processes of electron acceleration in the Fermi bubbles in order to define parameters and restrictions of the models, which are suggested for the origin of these giant radio and gamma-ray ...structures. In the case of the leptonic origin of the nonthermal radiation from the bubbles, these electrons should be produced somehow in situ because of the relatively short lifetime of high-energy electrons, which lose their energy by synchrotron and inverse-Compton processes. It has been suggested that electrons in bubbles may be accelerated by shocks produced by tidal disruption of stars accreting onto the central black hole or a process of re-acceleration of electrons ejected by supernova remnants. These processes will be investigated in subsequent papers. In this paper, we focus on in situ stochastic (Fermi) acceleration by a hydromagnetic/supersonic turbulence, in which electrons can be directly accelerated from the background plasma. We showed that the acceleration from the background plasma is able to explain the observed fluxes of radio and gamma-ray emission from the bubbles, but the range of permitted parameters of the model is strongly restricted.
Studies of the ozonation process when drying grain Baskakov, I V; Orobinsky, V I; Gulevsky, V A ...
IOP conference series. Earth and environmental science,
01/2020, Letnik:
422, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The article presents the main results of studies on the influence of ozone concentration in the ozone-air mixture acting as a drying agent on the efficiency of the efficiency of grain dryers of ...various types. The positive effect of gas on shortening the duration of the process, increasing the speed of drying, reducing energy costs, increasing the productivity of grain dryers, has been revealed. An analysis based on the results of research conducted by leading scientists in this field and our own experiments made it possible to determine the feasibility of preliminary ozonization of a wet grain heap in metal buffer storage silos before feeding it to a grain dryer. In general, the advantages of using ozone during the drying of grain material before the traditional method are revealed. Agricultural producers are recommended to equip buffer silos for temporary storage of grain with an ozonization system, which, according to preliminary studies, will reduce the moisture content of the heap by one pass through the mine dryer by up to 8.3%. At the moment, the percentage of moisture removed for one drying cycle does not exceed 6%.
The study of the “bifurcation memory” effect plays an important role in the study of dynamic features of real systems. Practical interest lies in studying the possibility of predicting a temporary ...decrease in response to control, which can significantly improve navigation safety. The effect of “bifurcation memory” is a temporary decrease in the phase velocity of the imaging point when passing through a certain area (“phase spot”) on the phase plane. A “phase spot” appears near the equilibrium state that disappeared during bifurcation. Over the almost half-century history of studying this dynamic feature, very few methods have been proposed that make it possible to unambiguously and with sufficient accuracy identify the “bifurcation memory” effect. This article proposes an improved phase plane method, which consists in constructing a phase velocity hodograph. A distinctive feature of the proposed method is not only that it surpasses previously developed methods in accuracy, but also covers both phase coordinates, and also gives an adequate result for any initial conditions. The method is quite universal and can be used to study the effect of “bifurcation memory” in various dynamic systems. Information about the boundary values of the parameter - the rudder angle, at which the effect of “bifurcation memory” begins (ends) to manifest itself can be used, for example, in the problem of optimizing the design of the hull and rudders or when creating control algorithms.
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