Dynamic susceptibility and dynamic correlations in spin ice

Here we calculate the dynamic susceptibility and dynamic correlation function in spin ice using the model of emergent magnetic monopoles. Calculations are based on a method originally suggested for the description of dynamic processes in water ice (non-equilibrium thermodynamics approach). We show that for zero temperature the dynamic correlation function reproduces the transverse dipole correlations (static correlation function) characteristic of spin ice in its ground state. At non-zero temperatures the dynamic correlation function includes an additional longitudinal component which decreases as the temperature decreases. Both terms (transverse and longitudinal) exhibit identical Debye-like dependences on frequency but with different relaxation times: the magnetic Coulomb interaction of monopoles reduces the longitudinal relaxation time with respect to the transverse one. We calculate the dielectric function for the magnetic monopole gas and discuss how the non-equilibrium thermodynamics approach exposes corrections to the Debye-Huckel theory of magnetic monopoles and the concept of "entropic charge".Comment: 5 pages, 2 figure

The impact of Nordic walking on the body in diseases acquired in the context of deteriorating environmental situation in the world

The article presents an analysis and interpretation of the health benefits of Nordic walking in general. The possibility of using this practice in diseases acquired in conditions of environmental degradation. Comparison of Nordic walking with brisk walking and jogging in terms of their effect on heart rate, maximum oxygen uptake, quality of life, and other health-related criteria. According to the study, Nordic walking was found to be a form of physical activity with compelling overall health benefits and had better short-term and long-term effects on the cardiorespiratory system compared to brisk walking. Short-term effects show higher heart rate, VO2, respiratory exchange rate, lactate thresholds, and calorie expenditure

Biomechanics of sports and technical skill, taking into account causal relationships and the effectiveness of technical actions

The article deals with the formation of technical skill with a close relationship of all aspects of an athlete's training, which is a complex dynamic system of conjugated interaction of structures and functions, due to the specifics of the high jump. The main objective of the study was to determine the true cause of the shortcomings in the athlete's movement technique, taking into account the complex causal relationships of factors that determine the high efficiency and stability of technical actions. The study revealed a system of relationships between these factors in high jumps; which is of fundamental importance for building and improving technical skills

Methods of genetic toxicology in the assessment of genomic damage induced by electromagnetic ionizing radiation

Medical or occupational exposure of patients and healthcare personnel to ionizing radiation (IR) can be a cause of genetic disorders. In this article we discuss the efficiency of the following tests used to comprehensively assess the effects of ionizing radiation on the genetic apparatus of a cell: The Ames test, the micronucleus test and the FISH method. We provide examples of their use, outline their advantages and drawbacks, estimate the possibility of designing more advanced test systems and discuss requirements for their implementation

Mechanisms of Dendrites Occurrence during Crystallization: Features of the Ice Crystals Formation

Dendrites formation in the course of crystallization presents very general phenomenon, which is analyzed in details via the example of ice crystals growth in deionized water. Neutral molecules of water on the surface are combined into the double electric layer (DEL) of oriented dipoles; its field reorients approaching dipoles with observable radio-emission in the range of 150 kHz. The predominant attraction of oriented dipoles to points of gradients of this field induces dendrites growth from them, e.g. formation of characteristic form of snowflakes at free movement of clusters through saturated vapor in atmosphere. The constant electric field strengthens DELs' field and the growth of dendrites. Described phenomena should appear at crystallization of various substances with dipole molecules, features of radio-emission can allow the monitoring of certain processes in atmosphere and in technological processes. Crystallization of particles without constant moments can be stimulated by DELs of another nature with attraction of virtual moments of particles to gradients of fields and corresponding dendrites formation.Comment: 6 page

Clinical examination of the eyes functional status and assessment of equivalent dose to eye lens in medical staff performing endovascular interventions under X-ray guidance

Growing use of X-ray guided surgery interventions leads to increase in the risk of radiation side effects in medical staff participating in image-guided interventional procedures. In this connection to protect health and ensure professional longevity of the interventionists are important scientific and social problems. The purpose of the study presented in the article is to assess radiation dose to the lens of eyes, doses to whole body and hands of medical staff performing X-ray-guided endovascular proce-dures. Doses were measured with the use of thermoluminescent dosimeters. Due to clinical eye ex-amination for above staff to assess abilities to refract the light existence of involution changes, which are unusual for a specific age of an examined person, are found. The study proves that new annual equivalent dose limit for the lens of the eyes of 20 mSv recommended by the IAEA is justified

Dynamic susceptibility of a spin ice near the critical point

We consider spin ice magnets (primarily, $\mathrm{Dy_2Ti_2O_7}$) in the vicinity of their critical point on the $(H,T)$ plane. We find that the longitudinal susceptibility diverges at the critical point, leading to the behaviour qualitatively similar to the one which would result from non-zero conductance of magnetic charges. We show that dynamics of critical fluctuations belongs to the universality class of easy-axis ferroelectric and calculate logarithmic corrections (within two-loop approximation) to the mean-field critical behavior.Comment: 5 pages, 3 figures. Some misprints are corrected, among them are the formula (20) and the estimation for $\Gamma_c