The possibilities of studying the reaction yields of
C
B,
N
B, and
N
N through measurements of induced (
B,
N) activities with thin
detector telescopes in temporal intervals between electron ...accelerator pulses have been analyzed. Estimates for the production of (
B,
N) nuclei and registration of their decay are provided, taking into account the parameters of the electron beam, Ta radiator, irradiated targets made of graphite or NH
NO
, and telescopes of plastic scintillation
detectors.
Proceeding from the comparison of parameters for the
-ray source based on backward Compton scattering, which is under development now, and the known methods of monitoring
-ray beams themselves to ...monitor the intensity and energy spectrum of
quanta in the beams from this
-ray source during photonicuclear research in the energy range from a few megaelectronvolts to
40 MeV, a system comprising scintillation plastic and inorganic detectors, as well as a magnetic pair spectrometer, has been proposed.
Based on the analysis of the progress in studying photonuclear reactions at
MeV and the unique parameters of the Compton source of
-quanta which is now under development, a program of priority ...photonuclear research using this source has been proposed. The program includes studies of the structure of giant E1- and pigmy resonances; cross sections of partial photonuclear reactions; nuclear resonance fluorescence; photofission; astrophysics and nucleosynthesis problems.
In this article, we describe an experimental verification of the correctness of registration of delayed neutrons from
238
U photofission at a maximum energy of 10 MeV of bremsstrahlung γ quanta on a ...pulsed linear electron accelerator LUE-8-5 in an interval of (1–5) ms after each beam pulse at times ≳7 min from the onset of irradiation. The measurements have been carried out using the scintillation spectrometer of fast neutrons based on a single stilbene crystal with pulse shape discrimination of γ quanta and fast neutrons. The temporal dependence of the counting rate of delayed neutrons in
238
U photofission has been measured at a repetition rate of 300 s
–1
in a time interval of (1.25–3.30) ms after the beam pulse.
The possibility of anisotropies in the speed of light relative to the limiting speed of electrons is considered. The absence of sidereal variations in the energy of Compton-edge photons at the ...European Synchrotron Radiation Facility's GRAAL facility constrains such anisotropies representing the first nonthreshold collision-kinematics study of Lorentz violation. When interpreted within the minimal standard-model extension, this result yields the two-sided limit of 1.6×10(-14) at 95% confidence level on a combination of the parity-violating photon and electron coefficients (κ(o+))(YZ), (κ(o+))(ZX), c(TX), and c(TY). This new constraint provides an improvement over previous bounds by 1 order of magnitude.
Experiments on measuring the energy spectra and time distributions of delayed neutrons are described. The neutrons are produced in
238
U photofission under the action of bremsstrahlung photons in the ...LUE-8-5 pulsed electron accelerator at the Russian Academy of Sciences’ Institute for Nuclear Research. The kinetic energy of incident electrons is ≈10 MeV. Measurements are made in the intervals between beam pulses. Fast neutrons are registered by a scintillation spectrometer, with identification of background γ quanta according to the shape of the scintillation pulses.
Extremal problems for vector potentials have wide applications in asymptotic analysis of Hermite-Padé approximants of analytic functions. We consider equilibrium vector logarithmic potentials with ...constrains on measures. We study the dependance of the supports of the equilibrium measures on their masses. We obtain the integral formulas for recovering the extremal measure of given mass from the supports of the equilibrium measures of smaller masses.
1. Vector logarithmic potential problems on equilibrium with different interaction between components (given by the interaction matrix) were first formulated and studied by Gonchar and Rahmanov (see ...1-5) in connection with research on asymptotic analysis of Hermite-Pade approximations. Since then the area of applications of vector logarithmic potential problems has essentially broadened. One modern application is the distribution of the eigenvalues of random matrix ensembles, or more precisely, ensembles of multiple orthogonal polynomials (see 6). In these applications the vector logarithmic potential problem is considered in the presence of an external field. We briefly introduce the terminology that will be needed for stating our results. To simplify the notation we restrict ourselves to the case of two dimensions and the so-called Nikishin interaction matrix (see 7).
The Aim. The aim of the study was to develop and evaluate the effectiveness of dietary therapy in obese patients on the basis of studying the polymorphism rs9939609 of the FTO gene.
Materials and ...methods. 100 patients with obesity of I-III degree aged from 18 to 55 years were examined. All patients underwent genotyping using allele-specific amplification with real-time detection of results. Depending on the genotypes of the FTO gene, obese patients received different diet therapy and were divided into 3 groups: patients with the TT and AT genotype received a standard low-calorie diet, and with the AA genotype a personalized diet.
Results. It was found that a decrease in the caloric content of the diet contributed to a decrease in body weight in obese patients, mainly due to muscle mass in carriers of the genotype AT, and in carriers of genotypes TT and AA - mainly due to the fat component.
Conclusions. Thus, the carriers of the mutant allele A in the homozygous and heterozygous variant require the selection of only a personalized diet. Therefore, in the appointment of dietary therapy to obese patients, it is recommended to carry out molecular genetic studies that will not only identify individuals with increased need for personalization of dietary therapy, but also increase the effectiveness of treatment for obesity and prevent the development of its complications.
The $\Sigma$ beam asymmetry in $\eta^{\prime}$ photoproduction off the proton was measured at the GrAAL polarized photon beam with incoming photon energies of 1.461 and 1.480 GeV. For both energies ...the asymmetry as a function of the meson emission angle shows a clear structure, more pronounced at the lowest one, with a change of sign around 90$^o$. The results are compared to the existing theories that fail to account for the data.
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