Atmospheric heavy metals are persistent, bioaccumulative, and toxic pollutants capable of long-range transport, posing significant ecological and public health risks. This review synthesizes five decades of research (1973–2024) on emission sources, transport mechanisms, deposition pathways, and monitoring approaches, supported by a bibliometric analysis of 1642 Scopus-indexed articles. Anthropogenic activities, including industrial operations, mining and smelting, vehicular emissions, and agricultural inputs, remain dominant contributors, while volcanic eruptions, geothermal activity, sea-spray aerosols, and soil-dust resuspension constitute important natural sources. Once emitted, metals associate with particulate matter (e.g., PM_2.5, PM₁₀), undergo atmospheric circulation, and are deposited through dry and wet processes, enabling transfer from urban centers to agricultural systems and remote environments. Urban areas exhibit the highest deposition loads, agricultural landscapes show substantial foliar uptake, and remote ecosystems display clear signatures of transboundary transport. Advances in analytical and biomonitoring techniques, including Atomic Absorption Spectroscopy, Inductively Coupled Plasma Mass Spectrometry, X-Ray Fluorescence, and moss-based bioindicators, have improved detection sensitivity. Mosses enhance sensitivity by acting as natural, long-term integrators of atmospheric deposition: their high surface-area-to-mass ratio, absence of cuticles and root systems, and direct uptake from precipitation and aerosols enable efficient accumulation of trace metals, revealing low-level and chronic deposition signals often missed by short-term instrumental air sampling. Bibliometric results reveal exponential growth in publications and strong collaboration networks centered in Asia, Europe, and North America, with underrepresentation in Africa, South America, and Central Asia. Key research gaps include limited long-term health assessments; insufficient real-time and low-cost monitoring technologies; low-resolution source apportionment; and minimal attention to emerging contaminants globally.

We construct superconformal mechanics with N = 3 and N = 4 supersymmetries that were inspired by analogy with the supersymmetric Schwarzian mechanics. The Schwarzian, being another system with superconformal symmetry, provides insight into the field content of supersymmetric mechanics, most notably, on the number and properties of the fermionic fields involved. Adding more fermionic fields (four in the N = 3 case and eight in the N = 4 case) made it possible to construct systems possessing maximal superconformal symmetries in N = 3 and N = 4, namely osp(3|2) and D(1, 2; α). In the case of N = 4 supersymmetry, we explicitly construct a new variant of N = 4 superconformal mechanics in which all bosonic subalgebras of the D(1, 2; α) superalgebra have a bosonic realization. In addition, the constructed systems involve the so(3) currents whose parameterization is not fixed, which allows one to consider different underlying geometries.

This short review is devoted to the celebration of two major events in quantum physics. The first one is the birth of the concept of Bose–Einstein condensation (1925) and the second is the experimental proof that it does exist and appears in liquid ⁴He simultaneously with superfluidity below the λ-point (1975).
Both of these events are tightly related to the Bogoliubov theory of superfluidity (1947). The existence of condensate in the system of interacting bosons is the key ansatz of this theory. Therefore, the experiments started at JINR-Dubna in 1975 confirmed this prediction of the Bogoliubov theory that superfluidity of liquid ⁴He (He II) should emerge at the same time as the Bose–Einstein condensation.

Corrected:
13 November 2025 (the captions to Figures 1 and 2 were changed)
26 November 2025 (changes were made in formulas (53) and (55))

We consider a complex rational degeneration of the hyperbolic Ruijsenaars model emerging in the limit ω₁ + ω₂ → 0 (or b → i in 2d CFT) and investigate the two-particle case in detail. Corresponding wave functions are described by complex hypergeometric functions in the Mellin–Barnes representation. Their dual integral representation and reflection symmetry in the coupling constant are established. Besides, a complex limit of the hyperbolic Baxter Q-operators is considered. Another complex degeneration of the hyperbolic Ruijsenaars model is obtained by taking a special ω₁ − ω₂ → 0 (or b → 1) limit. Additionally, two new degenerations to the complex Calogero–Sutherland type models are described.