The mixed spin-1 and spin- 3 2 Ising ferrimagnetic system with different anisotropies is studied within the mean-field theory based on Bogoliubov inequality for the Gibbs free energy. Global phase diagrams are obtained in the temperature-anisotropy plane. In particular we find first-order transition lines separating different low-temperature ordered phases (characterized by different values of the sublattice magnetizations) each one terminating at an isolated critical point. The existence and dependence of a compensation temperature on single-ion anisotropies is also investigated.

Mean-field solution of the mixed spin-1 and spin- Ising system with different single-ion anisotropies

The ferrimagnetic mixed spin and spin 1 Ising system

We present the exact formulation for the mixed spin - 1 2 and spin - 3 2 Blume–Capel Ising ferrimagnetic system on the Bethe lattice by the use of exact recursion relations. The exact expressions for the magnetization, quadrupole moment, Curie temperature and free energy are found and the phase diagrams are illustrated on the Bethe lattice with the coordination numbers q = 3 , 4, 5 and 6. It is found that the phase diagram of this mixed spin system only presents second-order phase transitions. The thermal variation of the magnetization belonging to each sublattice and the net magnetization are also presented.

Mixed spin-12 and spin-32 Blume–Capel Ising ferrimagnetic system on the Bethe lattice

Effect of uniaxial single-ion anisotropy upon magnetic properties of a mixed spin-1/2 and spin-S (S⩾1S⩾1) Ising model on a bathroom tile (4–8) lattice is examined within the framework of an exact star-triangle mapping transformation. Particular attention is focused on the phase diagrams established for several values of the quantum spin number S. It is shown that the mixed-spin bathroom tile lattice exhibits very similar phase boundaries as the mixed-spin honeycomb lattice whose critical points are merely slightly enhanced with respect to the former ones. The influence of uniaxial single-ion anisotropy upon the total magnetization vs. temperature dependence is particularly investigated as well.

Exact results of a mixed spin-1/2 and spin-S Ising model on a bathroom tile (4–8) lattice: Effect of uniaxial single-ion anisotropy

Within an effective-field formalism we study effects of different single-ion anisotropies on the magnetic properties (phase diagram, total and sublattice magnetizations) of a mixed spin-1 and spin- 3 2 Ising ferrimagnetic system on a honeycomb lattice. At a finite temperature we obtain quite a rich phase diagram with tricritical and fourth-order points. Some outstanding features are found in the temperature dependences of total and sublattice magnetizations.

The effect of anisotropies on the magnetic properties of a mixed spin-1 and spin- Ising ferrimagnetic system

We obtain the phase diagram of a ferromagnetic mixed Ising system, consisting of spin-1/2 and spin-S variables, on a Bethe lattice of coordination number z, with nearest-neighbor exchange interactions and single-ion terms. The problem is formulated as a discrete nonlinear map. There is a tricritical point for S integer and z\ensuremath{\ge}5. In the infinite-coordination-number limit, we regain the results of an exact calculation for a Curie-Weiss version of the model.

Mixed-spin Ising model on the Bethe lattice.

Dynamics of the ising model in a Cayley tree

Carbon in the labil fractions of soil organic matter in savannah areas

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Savannah biome and school: how they are contextualized in a current educational perspective

In northeastern Brazil, the drought history has been well documented, reflecting a resilient population with a robust regional identity. Last year, in response to the need to perpetuate water access and reduce scarcity, the Brazilian government implemented a program called the Program One Million Cisterns (P1MC). Considering that the need for water resource perpetuation can impact traditional knowledge transmission between generations, this study aimed to analyze the knowledge regarding rock pools in a small village located in a semiarid region in Brazil. The interviews addressed questions about the traditional knowledge, use, and management of rock pools. The abiotic and biological water variables were collected to establish the population's knowledge status. Our results identified that the use and management of rock pools were reduced after implementing P1MC. Despite the historical relevance of these ecosystems, their use was abandoned by most of the inhabitants, except for domestic use. Therefore, the transmission of traditional knowledge regarding rock pools have decreased between generations, compromising hydric security and representing a serious socio-economic risk for a region characterized by extreme droughts.

/pdf/phylosophical-essay-on-the-traditional-knowledge-and-use-of-1ayq2myv.pdf

N. R. da Silva

Papers

Mixed-spin Ising model on the Bethe lattice.

Dynamics of the ising model in a Cayley tree

Carbon in the labil fractions of soil organic matter in savannah areas

Savannah biome and school: how they are contextualized in a current educational perspective

Phylosophical Essay on the Traditional Knowledge and Use of Rock Pools in the Brazilian Drylands: Memory and Identity in Temporary Ecosystems