The study of frescoes dating back to the early sixteenth century in the Cathedral of the Nativity of the Virgin of the 8t Pherapont monastery revealed the presence of green copper pigments such as malachite, atacamite, posnjakite and natural pseudo-malachite.The minerals were identified by light microscopy, X-ray microspectrometry and X-ray diffraction.
Development of students’ mathematical skills is associated with quality teaching, which means that mathematics teachers should be able to successfully solve mathematical, teaching, and professional problems. The article aims to describe the assessment system of mathematics school teachers’ professional competence, which helps identify gaps in their training and design tailor-made retraining courses. 2,359 mathematics teachers from 13 regions of Russia participated in the research on 05–29 September 2017. Foremost, we conducted a survey and collected data about their teacher category and teacher expertise. Next, we provided a preliminary diagnostic test to enable the participants to self-assess their subject matter and teaching competencies. After that, they completed a three-part diagnostic test to assess their abilities to solve mathematical, teaching, and professional problems. Finally, the participants conducted video lessons. The three-part diagnostic test and video lessons allowed determining the professional competence level for every mathematics teacher. 24% participants showed level I of professional competence, 44% – level II, 9% – level II; 23% participants did not pass the basic level of professional competence. The results show that the mathematics teachers have difficulties in solving mathematical, teaching, or professional problems so tailor-made retraining courses are required. The developed assessment system underlies designing the courses.
Acid base and complexation properties of gem disubstituted phosphorus acids, viz., methylenediphosphonic, 1 hydroxyethylidene 1,1 diphosphonic, P,P´ diphenylmethylene diphosphinic, and P,P´ diphenyl 1 hydroxyethylidene 1,1 diphosphinic acids, were studied in aqueous solutions and in the presence of biomimetics (micelles of ionic surfactants). The dissociation constants of the acids and stability constants of complexes with magnesium(II) and copper(II) ions were determined in aqueous solutions and microheterogeneous media contain ing sodium dodecyl sulfate, cetylpyridinium chloride, or cetylpyridinium nitrate (ionic strength 0.1 mol L -1 , temperature 25 °С).
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