The quality of soils found in mines is low if they do not receive any reclamation treatment; yet, to the authors’ knowledge, there are still no equations to evaluate the quality of metal-contaminated mine soils after the application of the most widely used reclamation treatments (planting vegetation and amending with wastes). Therefore, the purposes of the present study were 1) to propose a method for developing soil quality indexes (SQIs); 2) to develop the SQIs for 2 types of mine soils (settling pond and mine tailing) reclaimed by planting trees, amending with wastes, or both; and 3) to assess the quality of these soils under field conditions. The results obtained after the use of an SQI developed for reclaimed mine soils through the selection of an SQI with a factor analysis and the totaling of the scores of the selected variables revealed that this method is a valid tool for developing SQIs. Applying this index with reclaimed mine soils showed that the untreated sites had a very low quality and that the treatment that most improved the soils was amending with wastes (sewage sludges and paper mill residues). The authors recommend the periodic addition of sewage sludges and paper mill residues to degraded sites as they increase the quality of soils, but the effects decrease over time.
The Full Strategy Minority Game (FSMG) is an instance of the Minority Game
(MG) which includes a single copy of every potential agent. In this work, we
explicitly solve the FSMG thanks to certain symmetries of this game.
Furthermore, by considering the MG as a statistical sample of the FSMG, we
compute approximated values of the key variable {\sigma}2/N in the symmetric
phase for different versions of the MG. As another application we prove that
our results can be easily modified in order to handle certain kind of initial
biased strategies scores, in particular when the bias is introduced at the
agents' level. We also show that the FSMG verifies a strict period two dynamics
(i.e., period two dynamics satisfied with probability 1) giving, to the best of
our knowledge, the first example of an instance of the MG for which this
feature can be analytically proved. Thanks to this property, it is possible to
compute in a simple way the probability that a general instance of the MG
breaks the period two dynamics for the first time in a given simulation.Comment: To appear in Physica
On a mathematical interaction model, developed to model metal uptake by plants and the effects on their growth, we introduce a modification which considers also effects on variations of acidity in soil. The model relates the dynamics of the uptake of metals from soil to plants and also variations of uptake according to the acidity level. Two types of relationships are considered: total and available metal content. We suppose simple mathematical assumptions in order to get as simple as possible expressions with the aim of being easily tested in experimental problems. This work introduces modifications to two versions of the model: on the one hand, the expression of the relationship between the metal in soil and the concentration of the metal in plants and, on the other hand, the relationship between the metal in the soil and total amount of the metal in plants. The fine difference of both versions is fundamental at the moment to consider the tolerance and capacity of accumulation of pollutants in the biomass from the soil.
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