The incarnation of the Nersesyan-Tsvelik model in (NO)[Cu(NO3)3]

The topology of the magnetic interactions of the copper spins in the nitrosonium nitratocuprate (NO)[Cu(NO3)3] suggests that it could be a realization of the Nersesyan-Tsvelik model, whose ground state was argued to be either a resonating valence bond (RVB) state or a valence bond crystal (VBC). The measurement of thermodynamic and resonant properties reveals a behavior inherent to low dimensional spin S = 1/2 systems and provides indeed no evidence for the formation of long-range magnetic order down to 1.8 K.Comment: 12 pages, 6 figure

Оценка числа решетчатых разбиений плоскости на центрально-симметричные полимино заданной площади

We study a problem about the number of lattice plane tilings by the given area centrosymmetrical polyominoes. A polyomino is a connected plane geomatric figure formed by joiining a finite number of unit squares edge to edge. At present, various combinatorial enumeration problems connected to the polyomino are actively studied. There are some interesting problems on enuneration of various classes of polyominoes and enumeration of tilings of finite regions or a plane by polyominoes. In particular, the tiling is a lattice tiling if each tile can be mapped to any other tile by a translation which maps the whole tiling to itself. Earlier we proved that, for the number T(n) of a lattice plane tilings by polyominoes of an area n, holds the inequalities 2n−3 + 2[ n−3 2 ] ≤ T(n) ≤ C(n + 1)3 (2, 7)n+1 . In the present work we prove a similar estimate for the number of lattice tilings with an additional central symmetry. Let Tc(n) be a number of lattice plane tilings by a given area centrosymmetrical polyominoes such that its translation lattice is a sublattice of Z 2 . It is proved that C1( √ 2)n ≤ Tc(n) ≤ C2n 2 ( √ 2.68)n . In the proof of a lower bound we give an explicit construction of required lattice plane tilings. The proof of an upper bound is based on a criterion of the existence of lattice plane tiling by polyominoes, and on the theory of self-avoiding walks on a square lattice.В работе рассматривается задача о числе решетчатых разбиений плоскости на центрально–симметричные полимино заданной площади. Полимино представляет собой связную фигуру на плоскости, составленную из конечного числа единичных квадратов, примыкающих друг к другу по сторонам. В настоящее время активно исследуются различные перечислительные комбинаторные задачи, связанные с полимино. Представляет интерес подсчет числа полимино определенных классов, а также подсчет числа разбиений конечных фигур или плоскости на полимино определенного типа. В частности, разбиение называется решетчатым, если любую фигуру разбиения можно перевести в любую другую фигуру параллельным переносом, переводящим все разбиение в себя. Ранее нами было доказано, что если T(n) – число решетчатых разбиений плоскости на полимино площади n, то справедливы неравенства 2 n−3 + 2[ n−3 2 ] ≤ T(n) ≤ C(n + 1)3 (2, 7)n+1 . В настоящей работе мы получаем аналогичную оценку для числа решетчатых разбиений, дополнительно обладающих центральной симметрией. Пусть Tс(n) – число решетчатых разбиений плоскости на центрально–симметричные полимино площади n, решетка периодов которых является подрешеткой решетки Z 2 . В работе доказано, что C1( √ 2)n ≤ Tс(n) ≤ C2n 2 ( √ 2.68)n . При доказательстве нижней оценки исполь- зована явная конструкция, позволяющая построить требуемое число решетчатых разбиений плоскости. Доказательство верхней оценки основано на критерии существования решетчатого разбиения плоскости на полимино, а также на теории самонепересекающихся блужданий на квадратной решетке

Оценка числа решетчатых разбиений плоскости на полимино заданной площади

We study a problem of a number of lattice plane tilings by given area polyominoes. A polyomino is a connected plane geometric figure formed by joining edge to edge a finite number of unit squares. A tiling is a lattice tiling if each tile can be mapped to any other tile by translation which maps the whole tiling to itself. Let T(n) be a number of lattice plane tilings by given area polyominoes such that its translation lattice is a sublattice of Z². It is proved that 2n−3 + 2[ n−3 2 ] ≤ T(n) ≤ C(n + 1)3 (2.7)n+1. In the proof of a lower bound we give an explicit construction of required lattice plane tilings. The proof of an upper bound is based on a criterion of the existence of lattice plane tiling by polyomino and on the theory of self-avoiding walk. Also, it is proved that almost all polyominoes that give lattice plane tilings have sufficiently large perimeters.Рассматривается задача о числе решетчатых разбиений плоскости на полимино заданной площади. Полимино представляет собой связную фигуру на плоскости, составленную из конечного числа единичных квадратов, примыкающих друг к другу по сторонам. Разбиение называется решетчатым, если любую фигуру разбиения можно перевести в любую другую фигуру параллельным переносом, переводящим все разбиение в себя. Пусть T(n) – число решетчатых разбиений плоскости на полимино площади n, решетка периодов которых является подрешеткой решетки Z² . Доказано, что 2 n−3 + 2[ n−3 2 ] ≤ T(n) ≤ C(n + 1)3 (2.7)n+1. При доказательстве нижней оценки использована явная конструкция, позволяющая построить требуемое число решетчатых разбиений плоскости. Доказательство верхней оценки основано на одном критерии существования решетчатого разбиения плоскости на полимино, а также на теории самонепересекающихся блужданий на квадратной решетке. Также доказано, что почти все полимино, дающие решетчатые разбиения плоскости, имеют большой периметр

Artificial intelligence in clinical physiology: How to improve learning agility

Clinical physiology involves a complete, comprehensive, multilateral study of the functions of both affected and healthy organs, which allows us to assess the compensatory capabilities of the body. Artificial intelligence is increasingly being used in medicine, including in clinical physiology. This is facilitated by the increase in computing processing power, development of cloud services and datasets, and numerous scientific articles demonstrating the effectiveness and viability of such intelligent solutions. Although the approach to medical dataset development is generally similar, there are a number of key features and significant differences in clinical physiology. Artificial intelligence systems in clinical physiology may be effectively trained and applied in practice by following the recommendations in this study. The national standard of the Russian Federation GOST R 59921.9-2022, which has entered into force, is included in the set of standards Artificial Intelligence systems in clinical medicine and establishes additional requirements for data analysis algorithms and test methods of artificial intelligence systems used in the field of clinical physiology. A crucial feature of the created standard is its qualimetric type (i.e., it has a mandatory set of demonstration data). Russia is one of the first countries to start developing quasi-metric standards worldwide, and 15 industry standards in the field of artificial intelligence (2 of them in medicine) will come into force this year

Ultrahigh compression of water using intense heavy ion beams: laboratory planetary physics

Intense heavy ion beams offer a unique tool for generating samples of high energy density matter with extreme conditions of density and pressure that are believed to exist in the interiors of giant planets. An international accelerator facility named FAIR (Facility for Antiprotons and Ion Research) is being constructed at Darmstadt, which will be completed around the year 2015. It is expected that this accelerator facility will deliver a bunched uranium beam with an intensity of 5x10(11) ions per spill with a bunch length of 50-100 ns. An experiment named LAPLAS (Laboratory Planetary Sciences) has been proposed to achieve a low-entropy compression of a sample material like hydrogen or water (which are believed to be abundant in giant planets) that is imploded in a multi-layered target by the ion beam. Detailed numerical simulations have shown that using parameters of the heavy ion beam that will be available at FAIR, one can generate physical conditions that have been predicted to exist in the interior of giant planets. In the present paper, we report simulations of compression of water that show that one can generate a plasma phase as well as a superionic phase of water in the LAPLAS experiments

Triple GEM Tracking Detectors for the BM@N Experiment

BM@N (Baryonic Matter at the Nuclotron) is the fixed target experiment aimed to study nuclear matter in the relativistic heavy ion collisions at the Nuclotron accelerator in JINR. The BM@N tracking system is based on Gas Electron Multipliers (GEM) detectors, mounted inside the BM@N analyzing magnet. The structure of the GEM detectors and the results of study of their characteristics are presented. The GEM detectors are integrated into the BM@N experimental setup and data acquisition system. The results of the first test of the GEM tracking system in the technical run with the deuteron beam are shortly reviewed

Beam-helicity asymmetries for single-hadron production in semi-inclusive deep-inelastic scattering from unpolarized hydrogen and deuterium targets

A measurement of beam-helicity asymmetries for single-hadron production in deep-inelastic scattering is presented. Data from the scattering of 27.6 GeV electrons and positrons off gaseous hydrogen and deuterium targets were collected by the HERMES experiment. The asymmetries are presented separately as a function of the Bjorken scaling variable, the hadron transverse momentum, and the fractional energy for charged pions and kaons as well as for protons and anti-protons. These asymmetries are also presented as a function of the three aforementioned kinematic variables simultaneously