The paper deals with the resonance oscillations of a drop (bubble) surrounded by a fluid of different density in a container subjected to small amplitude vibrations in zero gravity conditions. The drop size is considered to be large in comparison with both the vibration amplitude and the thickness of viscous Stokes layers. The calculations for parametrically excited oscillations of the drop are carried out in the linear approximation, for inviscid and low viscous media, neglecting compressibility effects. The resonant oscillation is a doublet of neighbouring modes of eigen-oscillations of the drop, for which the sum of frequencies coincides with the frequency of the forced vibrations. This means that the basic state becomes unstable against quasi-periodic oscillations. The finite viscosity implies a finite threshold for the excitation of resonance. On the other hand, the viscosity plays a destabilizing role; at non-zero (even infinitesimal) viscosity the width of the instability frequency range turns out to be greater than in the case of inviscid fluids.

When a complex emergency (CE) overwhelms infrastructure, the ability of health-care providers to work efficiently under duress saves lives. The author uses her experience of providing mental health supports to humanitarian aid workers and the pieces of training conducted for internal medicine practitioners to offer guidance on how to manage severe job-related stresses during the response to the coronavirus disease 2019 (COVID-19) pandemic. This work reminds responders about their professional mission and purpose, but its extreme physical and mental demands can take a toll on their well-being and health. In CEs, the sheer volume of work and the emotional over-engagement tend to produce toxic fantasies (eg, rescuer or helper fantasies), acting upon which threatens integrity of care and increases risks for both patients and providers. Accumulated fatigue and exposure to mass suffering and mortality can change the perceived value of life and increase reckless, risk-taking, and suicidal behaviors. Introducing a self-awareness framework prioritizes the awareness of the available choices and making situation-appropriate and informed decisions about balancing one’s own and others’ needs. The COVID-19 response has demonstrated that fostering peer supports, changing organizational culture, addressing self-awareness within a training and supervisory context, and strengthening supports for managers are important parts of disaster preparedness. It also revealed that more research is needed to better understand and meet the special psychological needs of health-care responders.

Global mental health (GMH) work reminds us about our professional ideals and mission. GMH specialists conduct research and provide psychosocial and mental health support to populations affected by humanitarian crises around the world. This work exposes these specialists to situations with a high degree of moral ambiguity and no good solutions, where humanitarian accountability takes priority over conflicting values. Self-awareness helps to address the countertransference that confounds complex decision-making and can compromise the health and safety of all involved. The evolving role of GMH as a humanitarian actor underscores the importance of professional competencies in assuring the integrity and standards of practice.

We use the invariant Γ integral of fracture mechanics to calculate the frontal pressure and resistance to the downward motion a of snow avalanche. A basic characteristic property of the snowpack, termed the entrainment toughness, is introduced. From an analysis of the non-entrainment frictional mechanisms of avalanches, we find the necessary condition for a fracture-entrainment regime, and from an analysis of limiting equilibrium of gravitational force and frontal resistance, the necessary condition equation for the start of avalanches. We then derive the governing equations for the dynamics of avalanches, using a point-mass approach with entrainment taken into account. The governing equations are used to numerically simulate the Vallée de la Sionne (Switzerland) avalanche of 7 February 2003.

Samples with overall composition HoxSr1−xCoO3−δ within the range 0.05 ≤ x ≤ 0.9 were prepared by a solid-state technique at 1100 °C in air. Single-phase HoxSr1−xCoO3−δ oxides were obtained within the range 0.05 ≤ x ≤ 0.30. Solid solutions of Ho0.05Sr0.95CoO3−δ and Ho0.1Sr0.9CoO3−δ were indexed in the cubic structure (Pm3m sp. gr.) with the unit cell parameters a = 3.846 Å and a = 3.842 Å, respectively. Further introduction of holmium leads to a change of crystal structure from cubic to a tetragonal 2ap × 2ap × 4ap superstructure. All samples with x > 0.3 were multiphase, containing a saturated solid solution with approximate composition Ho0.3Sr0.7CoO3−δ with Ho2O3 and CoO. The change of oxygen nonstoichiometry was measured by thermogravimetric analysis within the temperature range 25 ≤ T (°C) ≤ 1100. The absolute value of oxygen nonstoichiometry was calculated from the results of chromatometric titration. Thermal expansion coefficients of Ho1−xSrxCoO3−δ were measured by dilatometry within the temperature range 25 ≤ T (°C) ≤ 1100 in air.

Layered LnBa(Co,Me)2O5+δ (Ln = Nd, Sm, Ho and Y; Me = Fe, Ni, Cu) with double perovskite structure were synthesized by the solid-state reaction and glycerin-nitrate technique and characterized by X-ray diffraction, thermogravimetric analysis, iodometric titration and dilatometry. Homogeneity ranges for the solid solutions were determined. The oxygen content in LnBa(Co,Me)2O5+δ decreases with decreasing rare-earth cation size. Partial substitution of cobalt by iron increases oxygen content while introduction of copper decrease it. The average thermal expansion coefficients were calculated. Chemical compatibility of studied perovskites with Ce0.8Sm0.2O2 and Zr0.85Y0.15O2 solid electrolytes has been studied.

We show that two-dimensional Si/Ge nanostructures with a thickness of a single atomic layer can be imaged with chemical sensitivity using a scanning tunneling microscope (STM). An atomic layer of Bi terminating the surface is used to distinguish between Si and Ge. This distinction between Si and Ge enabled us to fabricate two-dimensional Si/Ge nanostructures in a controlled way by self-organized growth. Si/Ge nanoring structures consisting of alternating Si and Ge rings having a width of ∼5 nm were grown around a Si core on a Si(111) substrate by molecular beam epitaxy (MBE). The thickness of the Si and Ge rings is only one atomic layer (0.3 nm). Alternating Si/Ge nanowires with a width of ∼3.5 nm and a thickness of 0.3 nm were also fabricated using alternating Si/Ge deposition in the step flow growth mode.

A kinetic modelling approach was developed and investigated with the aim of predicting the utilization of major substrates in the mammary gland and milk secretion rates in the lactating cow at varying concentrations of substrate in arterial blood. The model includes kinetic equations of transport and metabolism of glucose, acetate, free amino acids and free fatty acids in secretory cells and a phenomenological description of autoregulation of local blood flow, in which an energy criterion of control has been used. The predicted relationships between the rate of milk secretion and glucose levels in the blood are consistent with experimental results. Differential stimulation of α-lactalbumin synthesis causes increments in local blood flow and milk secretion rate in the model. The results of the study suggest that there is no simple relationship between the level of substrates in the blood and milk yield and contents of fat and protein in milk. This is because the effect on production of varying patterns of substrate concentrations in the blood is mediated by network interactions at the level of secretory cell metabolism and microcirculation. However, dynamic modelling provides a rational framework for developing such predictive tools.