A more elemental solution was needed.
In this case ρs is the density of the elemental solution which is nothing but 2% acidified de-ionized water.
This result shows that the rats had not acquired a conditional elemental solution as this strategy might solve two but not all three discriminations concurrently.
Simply training a rat to learn W|B+ versus B|W− risks the confound that a rat which always looks to the left could solve the simpler problem W+ versus B− (a similar elemental solution exists if the rat always looks to the right, B+ versus W−).
Such tasks may well tax configural learning, although these same tasks cannot preclude elemental solutions; for example, different angles or faces of the object become exposed, whereas the perceptual properties of a feature might be influenced by a change in the neighboring element.
Multi-elemental solutions of 1,000 mg L−1 ICP Standard Certipur® Merckk, Darmstadt, Germany) containing the analysed elements (Fe, Mn, Al, Mg, Pb, Zn, Cr, Cu, Cd, Ni, and As) were used for calibration.
A reference rock standard (JSO-1, Geological Survey of Japan) was used to calibrate samples as well as standard solutions prepared from pure elemental standard solutions (Wako Pure Chemical Industry Ltd., Osaka, Japan).
Calibration was carried out with elemental standard solutions.
For metals' determination in plants and their aqueous extracts, the calibration standards were prepared by diluting the reference multi-elemental standard solution in 8% (v/v) nitric acid and 0.5% (v/v) nitric acid, respectively, in order to assure the similar concentration of nitric acid in samples and in calibration standards.
Elemental stock solutions of In (0.5 M InCl3 in TOP), Cu (0.5 M CuCl in TOP) and Se (1.0 M Se in TOP) were prepared by dissolving the elements in TOP at room temperature.
When measured amount of elemental sulfur stock solution was added to reaction system (water solution), acetone concentration was always less than 2% and sulfur colloid formed immediately due to the change in solubility.
