Exact results of the mixed-spin Ising model on a decorated square lattice with two different decorating spins of integer magnitudes

The mixed-spin Ising model on a decorated square lattice with two different decorating spins of the integer magnitudes S_B = 1 and S_C = 2 placed on horizontal and vertical bonds of the lattice, respectively, is examined within an exact analytical approach based on the generalized decoration-iteration mapping transformation. Besides the ground-state analysis, finite-temperature properties of the system are also investigated in detail. The most interesting numerical result to emerge from our study relates to a striking critical behaviour of the spontaneously ordered 'quasi-1D' spin system. It was found that this quite remarkable spontaneous order arises when one sub-lattice of the decorating spins (either S_B or S_C) tends towards their 'non-magnetic' spin state S = 0 and the system becomes disordered only upon further single-ion anisotropy strengthening. The effect of single-ion anisotropy upon the temperature dependence of the total and sub-lattice magnetization is also particularly investigated.Comment: 17 pages, 6 figure

Funktionskreis and the biosemiotic signifieds: Towards the integration of semiotics

The following is a brief synopsis of the 2021 summer Semiosalong event titled “Funktionskreis and the biosemiotic signifieds”, held at the Karl Ernst von Baer House, Tartu, Estonia, with presentations by the authors of this review. The included talks revolve around the idea of a ‘second major turn in biosemiotics’ following the more ‘Peircean inspired biology’ turn of the last few decades of the 20th century, and reconciling its findings with other theoretical foundations of general semiotics, such as structural semiology. The aesthetic and textual concerns of the latter invite commentary from the biosemiotic perspective