Springer最新文献

The basic ideas of application of the self-similarity approach in relativistic physics are presented. The production of π-mesons in n + p and p + C reactions is described in terms of self-similar variables. The self-similarity approach provides adequate description of experimental data in the intermediate energy range, where the simplest special case of self-similarity—the scaling approach—is inapplicable. The application of the self-similarity approach to description of particle production and acceleration by ultrashort high-intensity laser pulses is demonstrated.

The role of volatile organic compounds (VOCs) in plant-insect interactions has been studied in detail in recent decades, especially in the context of environment-friendly integrated pest management (IPM) in agroecosystems. Field-based study and behavioural investigations have shown that specific VOCs (or combinations of VOCs) of companion crops are crucial in diverting phytophagous insects from main food or cash crops, along with attracting beneficial insects which decimate pest species. The functional mechanisms of these olfactory cues, however, are not always clear and distinctive, especially since these ecological interactions are highly variable. The complex 'odourscapes' occurring in mixed cropping systems are determined by species-specific interactions, local climate, prevalent agricultural/landscaping practices, and other environmental factors which need to be examined in localized contexts. This review aims to cover the dynamics and mechanisms of VOCs mediating plant-insect interactions in mixed crop settings, the variables and technical constraints to be considered for implementing these interactions for cost-effective IPM, and potential challenges presented by ecological fine-tuning of such interactions.

Inelastic neutron scattering by the ⁴⁸Ti nucleus with the formation of the 1st excited state of the target nucleus in the output channel, followed by the transition of the nucleus to the ground state by the emission of a gamma-ray quantum, is studied. For the incident neutron energies ranging from 1.2 to 2.3 MeV, the differential cross sections of both inelastic neutrons scattering and the γ radiation under consideration are calculated. The calculations made take into account both direct reactions and reactions occurring through the compound nucleus.

Odd–odd nuclei near the remote double-magic nucleus (^{{78}}{text{Ni}}) are investigated within the random-phase approximation. Level energies and probabilities of electromagnetic transitions between levels of the corresponding nuclei are calculated. The results obtained are compared with the available sparse experimental data.

The half-life T_1/2 of ⁷¹Ge nuclei was measured using a Si(Li) detector. The obtained value T_1/2 = 11.473 ± 0.026 (stat.) days is consistent with recent results, which excludes the possibility of explaining the “gallium anomaly” by a longer half-life of ⁷¹Ge.

Detection of gamma radiation from photonuclear reactions to form radionuclides was investigated at the LUE-8-5 linear electron accelerator. The intensities of bremsstrahlung, scattered, and activation gamma radiation were measured in real time. Using the induced-activity method, the yields of excitation reactions of indium and cadmium isomers at photon energies up to 8 MeV were determined.

A long-term monitoring of radon volumetric activity was carried out at the Laboratory of Nuclear Processes of the St. Petersburg State University. The dependences of radon volumetric activity on temperature, humidity, and pressure were determined. The analysis of the presented data made it possible to identify areas with the highest and lowest radon concentrations in the air and to assess the influence of external factors on the processes of radon formation and accumulation.

For a clock based on isomeric ^229mTh nuclei the possibility of using the frequency of isomeric transition photons from sources with the isomers obtained by laser excitation of ²²⁹Th nuclei in crystals or from the α-decay of ²³³U in a hydrochloric acid solution as a reference frequency is considered.

The UrQMD 3.4 model, which was designed to generate Monte Carlo events of multiple particle creation processes in hadron–nucleus and nucleus–nucleus collisions, has been supplemented with an algorithm of calculation of the excitation energies of residual nuclei and their composition. Relaxation of residual nuclei produces free neutrons, light evaporation particles, and nuclear fragments. This allows for a satisfactory description of experimental data on spectra of mesons, neutrons, protons and nuclear fragments at high energies.

The effect of low-energy ionizing radiation in the dose range of 5–30 Gy on the biological performance of rapeseed (Brassica napus) seeds was investigated. Presowing irradiation led to an improvement in both germination rate and crop productivity. X-ray irradiation at doses of 15, 20, and 25 Gy increased rapeseed yield by 298, 130, and 202%, respectively, in comparison with a reference group. Irradiation with accelerated electrons at doses of 30 and 25 Gy increased the yield by 42 and 126%, respectively.