Supernova Ia: a Converging Delayed Detonation Wave

A model of a carbon-oxygen (C--O) presupernova core with an initial mass 1.33 M_\odot, an initial carbon mass fraction 0.27, and with an average mass growth-rate 5 x 10^{-7} M_\odot/yr due to accretion in a binary system was evolved from initial central density 10^9 g/cm^3, and temperature 2.05 x 10^8 K through convective core formation and its subsequent expansion to the carbon runaway at the center. The only thermonuclear reaction contained in the equations of evolution and runaway was the carbon burning reaction 12C + 12C with an energy release corresponding to the full transition of carbon and oxygen (with the same rate as carbon) into 56Ni. As a parameter we take \alpha_c - a ratio of a mixing length to the size of the convective zone. In spite of the crude assumptions, we obtained a pattern of the runaway acceptable for the supernova theory with the strong dependence of its duration on \alpha_c. In the variants with large enough values of \alpha_c=4.0 x 10^{-3} and 3.0 x 10^{-3} the fuel combustion occurred from the very beginning as a prompt detonation. In the range of 2.0 x 10^{-3} >= \alpha_c >= 3.0 x 10^{-4} the burning started as a deflagration with excitation of stellar pulsations with growing amplitude. Eventually, the detonation set in, which was activated near the surface layers of the presupernova (with m about 1.33 M_\odot) and penetrated into the star down to the deflagration front. Excitation of model pulsations and formation of a detonation front are described in detail for the variant with \alpha_c=1.0 x 10^{-3}.Comment: 13 pages, 11 figures, to appear in Astronomy Letter

DEPRESSIVE CONDITIONS ASSUMED AS A MEDICO-SOCIAL PHENOMENON

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Six-loop ε\varepsilon expansion study of three-dimensional nn-vector model with cubic anisotropy

The six-loop expansions of the renormalization-group functions of $\varphi^4$ $n$-vector model with cubic anisotropy are calculated within the minimal subtraction (MS) scheme in $4 - \varepsilon$ dimensions. The $\varepsilon$ expansions for the cubic fixed point coordinates, critical exponents corresponding to the cubic universality class and marginal order parameter dimensionality $n_c$ separating different regimes of critical behavior are presented. Since the $\varepsilon$ expansions are divergent numerical estimates of the quantities of interest are obtained employing proper resummation techniques. The numbers found are compared with their counterparts obtained earlier within various field-theoretical approaches and by lattice calculations. In particular, our analysis of $n_c$ strengthens the existing arguments in favor of stability of the cubic fixed point in the physical case $n = 3$

Results of investigation of muon fluxes of superhigh energy cosmic rays with X-ray emulsion chambers

The overall data from the investigation of the cosmic ray muon flux in the range of zenith angles (0-90) deg within the energy range (3.5 to 5.0) TeV is presented. The exposure of large X-ray emulsion chambers underground was 1200 tons. year. The data were processe using the method which was applied in the experiment Pamir and differred from the earlier applied one. The obtained value of a slope power index of the differential energy spectrum of the global muon flux is =3.7 that corresponds to the slope of the pion generation differential spectrum, gamma sub PI = 2.75 + or - .04. The analysis of the muon zenith-angular distribution showed that the contribution of rapid generation muons in the total muon flux agree the best with the value .2% and less with .7% at a 90% reliability level

Specific features of spin-variable properties of [Fe(acen)pic2]BPh4 · nH2O

© 2016, Pleiades Publishing, Ltd. The [Fe(acen)pic2]BPh4 · nH2O compound has been synthesized and studied in the temperature interval of 5–300 K by the methods of EPR and magnetic susceptibility. The existence of ferromagnetic interactions between Fe(III) complexes in this compound has been revealed, in contrast to unhydrated [Fe(acen)pic2]BPh4. The reduction in the integrated intensity of the magnetic resonance signal as the temperature decreases below 80 K has been explained by the transition of high-spin ions to the low-spin state. It has been shown that the phase transition temperature in the presence of intermolecular (ferromagnetic) interactions is lower than that in the case of noninteracting centers

Specific features of spin-variable properties of [Fe(acen)pic2]BPh4 · nH2O

© 2016, Pleiades Publishing, Ltd. The [Fe(acen)pic2]BPh4 · nH2O compound has been synthesized and studied in the temperature interval of 5–300 K by the methods of EPR and magnetic susceptibility. The existence of ferromagnetic interactions between Fe(III) complexes in this compound has been revealed, in contrast to unhydrated [Fe(acen)pic2]BPh4. The reduction in the integrated intensity of the magnetic resonance signal as the temperature decreases below 80 K has been explained by the transition of high-spin ions to the low-spin state. It has been shown that the phase transition temperature in the presence of intermolecular (ferromagnetic) interactions is lower than that in the case of noninteracting centers

Lability of spin state of Fe(III) complexes with tetradentate Schiff’s bases

© 2016, Pleiades Publishing, Ltd.[FeLX2]Y [L = N,N'-ethylenebis(salicylimine) (salen), N,N'-ethylenebis(acetylacetonylimine) (acen), or N,N'-ethylenebis(3-methyloxysalicylimine) (vanen); X = imidazole or N-methylimidazole; Y = BF4, ClO4, or BPh4] compounds have been prepared and studied by means of EPR and magnetic susceptibility measurements at 5–300 K. It has been shown that the different electron-donating properties of acen and salen planar ligands result in different spin states of Fe(III) ions. Intermolecular π-interactions of the outer-sphere BPh4 ion affect the complexes spin state as well

On the estimate of the sigma^(I = 1)_(KN)(0)-term value from the energy level shift of kaonic hydrogen in the ground state

Using the experimental data on the energy level shift of kaonic hydrogen in the ground state (the DEAR Collaboration, Phys. Rev. Lett. 94, 212302 (2005)) and the theoretical value of the energy level shift, calculated within the phenomenological quantum field theoretic approach to the description of strong low-energy anti-K N and anti-K NN interactions developed at Stefan Meyer Institut fuer subatomare Physik in Vienna, we estimate the value of the sigma^(I = 1)_(KN)(0)-term of low-energy anti-K N scattering. We get sigma^(I = 1)_(KN)(0) = (433 +/- 85) MeV. This testifies the absence of strange quarks in the proton structure.Comment: 7 pages, no figure

Content of biologically active substances in sweet cherry fruits at different stages of fruit development in the conditions of the living mulch

Received: August 19th, 2022 ; Accepted: October 7th, 2022 ; Published: October 19th, 2022 ; Correspondence: [email protected]Сontent of soluble solids, sugars, titrated acids, ascorbate, glutathione, phenolic substances, anthocyanins, total reducing activity of fruits tissues in sweet cherry fruits studied at different stages of fruit development during 2018 and 2019 in an organic sweet cherry orchard (Prunus avium L. / Prunus mahaleb) in the Southern Steppe of Ukraine. The aim of the research was to determine how the living much conditions (compared to bare fallow) affect the content of biologically active substances in sweet cherry fruits at different stages of ripening. It was determined that the fruits of sweet cherry accumulated significantly more ascorbate, phenolic substances and anthocyanins in the conditions of living mulch (compared to the fruits of the trees on bare fallow). So, at the stage of picking ripeness, the content of ascorbate in sweet cherry fruits in the conditions of living mulch was 29 and 22% more compared to bare fallow (respectively, in 2018 and 2019), phenolic substances - by 47 and 23%, anthocyanins - by 36 and 26%. The revealed regularities can be explained by stressful conditions of competition with natural herbs, which activate the synthesis of anti-stress, antioxidant biologically active substances in plant tissues (including fruits). Since it is the antioxidants of the fruits that have a physiological value for humans, it can be stated that the fruits grown in the conditions of living mulch have a higher therapeutic and preventive value than the fruits grown on bare fallow