Antiproton-nucleus potentials from global fits to antiprotonic X-rays and radiochemical data

We report on global fits of optical-model parameters to 90 data points for $\bar p$ X-rays and 17 data points of radiochemical data put together. With the help of separate fits to the two kinds of data it is possible to determine phenomenologically the radial region where the absorption of antiprotons takes place and to obtain neutron densities which represent the average behaviour over the periodic table. A finite-range attractive and absorptive $\bar p$-nuclear isoscalar potential fits the data well. Self-consistent dynamical calculations within the RMF model demonstrate that the polarization of the nucleus by the {\it atomic} antiproton is negligible.Comment: 18 pages, 6 figures, one table. Extended discussion, to appear in Nucl. Phys.

Neutron halos in heavy nuclei -- relativistic mean field approach

Assuming a~simple spherical relativistic mean field model of the nucleus, we estimate the width of the antiproton--neutron annihilation ($\Gamma_n$) and the width of antiproton--proton ($\Gamma_p$) annihilation, in an antiprotonic atom system. This allows us to determine the halo factor $f$, which is then discussed in the context of experimental data obtained in measurements recently done on LEAR utility at CERN. Another quantity which characterizes the deviation of the average nuclear densities ratio from the corresponding ratio of the homogeneous densities is introduced too. It was shown that it is also a good indicator of the neutron halo. The results are compared to experimental data as well as to the data of the simple liquid droplet model of the nuclear densities. The single particle structure of the nuclear density tail is discusssed also.Comment: revtex, 12 pages + 6 postscript figure

Leakage Resilience of the Blom’s Key Distribution Scheme

We initiate the study of the leakage-resilience of the information-theoretic key distribution schemes. Such schemes, originally proposed in the 1980s, have recently attracted a lot of interest in the systems community. This is because, due to their extreme efficiency, they can be executed on low-cost devices such as sensors, where the use of the public-key cryptography is infeasible. We argue that the study of leakage resilience of such schemes is particularly well-motivated, since, unlike more expensive devices, the sensors (or other similar devices) are unlikely to be physically resilient to leakage. We concentrate on the classical scheme of Blom (CRYPTO 1982), since it is known to be optimal in a large class of such schemes. We model the leakage as an input-shrinking function. In this settings we show that Blom’s scheme is leakage-resilient in a very strong model, where the adversary can (1) compromise completely some nodes in a “standard” way, and (2) leak information jointly from the remaining nodes. The amount leakage that we can tolerate can be up to (0.5−ϵ) of the total amount of information on the leaking nodes. We also show that this bound is optimal, by providing an attack that breaks the scheme if more leakage is available to the adversary. This attack works even in a weaker model, where the nodes leak information independently. In the proof we make use of the theory of the randomness extractors. In particular we use the fact that inner product over a finite field is a good 2-source extractor. This is possible since the Blom’s scheme is based on the matrix multiplication

Shot-down stable processes

Bogdan K, Jastrzȩbski K, Kaßmann M, Kijaczko M, Popławski P. Shot-down stable processes. arXiv:2301.12290. 2023.The shot-down process is a strong Markov process which is annihilated, or shot down, when jumping over or to the complement of a given open subset of a vector space. Due to specific features of the shot-down time, such processes suggest new type of boundary conditions for nonlocal differential equations. In this work we construct the shot-down process for the fractional Laplacian in Euclidean space. For smooth bounded sets $D$, we study its transition density and characterize Dirichlet form. We show that the corresponding Green function is comparable to that of the fractional Laplacian with Dirichlet conditions on $D$. However, for nonconvex $D$, the transition density of the shot-down stable process is incomparable with the Dirichlet heat kernel of the fractional Laplacian for $D$. Furthermore, Harnack inequality in general fails for harmonic functions of the shot-down process

The 4

The 41Σ+ state of LiCs molecule is observed experimentally for the first time. The inverted perturbation approach (IPA) method is used to derive the potential energy curve of the state from the measured spectra. The experiment is accompanied by theoretical calculations of adiabatic potentials for excited states in LiCs including 41Σ+, performed with the MOLPRO program package. The irregular shape of the 41Σ+ state potential predicted by theory is confirmed in the experiment

Методичні засади підготовки курсантів до змагань з військово-прикладного семиборства

The purpose of the research is to develop methodical bases of training of cadets for the military applied heptathlon competitions. Material and methods: Cadets of 2-3 courses at the age of 19-20 years (n=20) participated in researches. Cadets were selected by the best results of exercises performing included into the program of military applied heptathlon competitions (100 m run, 50 m freestyle swimming, Kalashnikov rifle shooting, pull-up, obstacle course, grenade throwing, 3000 m run). Preparation took place on the basis of training center. All trainings were organized and carried out according to the methodical basics: in a week preparation microcycle five days cadets had two trainings a day (on Saturday was one training, on Sunday they had rest). The selected exercises with individual loads were performed, Results : Sport scores demonstrated top results in the performance of 100 m run, 3000 m run and pull-up. The indices of performing exercise "obstacle course" were much lower than expected. Rather low results were demonstrated in swimming and shooting. Conclusions . Results of researches indicate the necessity of quality improvement: cadets’ weapons proficiency; physical readiness to perform the exercises requiring complex demonstration of all physical qualities.Цель: разработать методические основы подготовки курсантов к участию в соревнованиях по военно-прикладному семиборью. Материал: В исследованиях приняли участие курсанты 2-3 курсов возрасте 19-20 лет (n=20). Курсанты отбирались по лучшим результатам выполнения упражнений, входящих в программу соревнований по военно-прикладному семиборью (бег 100м, плавание 50м вольным стилем, стрельба из автомата Калашникова, подтягивание, полоса препятствий, метание гранаты, бег 3000м). Подготовка проходила на базе учебного центра. Все занятия были построены и проводились в соответствии с методическими основами: в недельном микроцикле подготовки пять дней курсанты выполняли по две тренировки в день (суббота - одна тренировка, в воскресенье - отдых). Применялись специально подобранные упражнения с индивидуализацией нагрузки. Результаты. По результатам соревнований были зафиксированы высокие результаты при выполнении упражнений бег 100 и 3000м, подтягивание. Показатели выполнения упражнения «полоса препятствий» были значительно ниже ожидаемых. Достаточно низкие результаты были показаны в плавании и стрельбе. Выводы. Результаты исследований указывают на необходимость повышения качества: огневой подготовки курсантов; физической готовности выполнять упражнения, требующие комплексного проявления всех физических качеств.Мета: розробити методичні основи підготовки курсантів до участі в змаганнях з військово-прикладного семиборства. Матеріал: У дослідженнях взяли участь курсанти 2-3 курсів віці 19-20 років (n = 20). Курсанти відбиралися за кращими результатами виконання вправ, що входять в програму змагань з військово-прикладного семиборства (біг 100м, плавання 50м вільним стилем, стрільба з автомата Калашникова, підтягування, смуга перешкод, метання гранати, біг 3000м). Підготовка проходила на базі навчального центру. Всі заняття були побудовані і проводилися відповідно до методичних основ: в тижневому мікроциклі підготовки п'ять днів курсанти виконували по два тренування в день (субота - одне тренування, у неділю - відпочинок). Застосовувалися спеціально підібрані вправи з індивідуалізацією навантаження. Результати. За результатами змагань були зафіксовані високі результати при виконанні вправ біг 100 та 3000м, підтягування. Показники виконання вправи «смуга перешкод» були значно нижче очікуваних. Досить низькі результати були показані в плаванні і стрільбі. Висновки. Результати досліджень вказують на необхідність підвищення якості: вогневої підготовки курсантів; фізичної готовності виконувати вправи, що вимагають комплексного прояву всіх фізичних якостей