Zone of Proximal Development

Consequently we have selected three tasks in three relevant domains of chemistry and (material or food) technology which are expected to be within the zone of proximal development for students ... 

Educational constructivism extended the realism-empiricism dichotomy into how individuals learn, and assumed two main forms (19) (i) personal constructivism, which is associated with Piaget (5) and (ii) social-cultural constructivism which is linked to Vygotsky. Piagetian constructivism is associated with an idealized person (the epistemic subject ). On die other hand, according to Vygotsky (20), the learner constructs actively his/her knowledge, but this process is greatly assisted by interactions with peers and with the teacher who acts at the students zone of proximal development. 

To respond to such calls Sileshi and Barke - after reviewing the major chemistry education concepts - proposed the Tetrahedral-ZPD metaphor. This metaphor re-hybridizes the very powerful 3D-tetrahedral chemistry education concept proposed by Mahaffy [22] macroscopic, molecular, representational, and human element. With the idea of the Zone of Proximal Development (ZPD) of social constructivist Vygotsky [23], ZPD should describe the distance between the actual development level as determined by independent problem solving and the level of potential development as determined through problem solving under adult guidance or in collaboration with more capable peers [23],... 

The morphological and functional development of the kidney has extensively been studied in rats. There is a rapid differentiation of the renal cortex after birth (83). The proximal segments of the tubules grow most rapidly, and micropuncture techniques have shown that glucose is reabsorbed solely by this segment of the tubule. Baxter and Yoffey have reported that in the newborn rat the peripheral region of the renal cortex is characterized by a neogenic zone of undifferentiated tissue, which cannot store the vital dye, trypan blue. By 28 days after birth, the tubules... 

Microbial pesticides rely on their ability to either infect the pest resulting in an infection or disease or in their ability to inhibit the pest s growth by production of active metabolites. Hence it becomes essential to deliver the pesticidal organism in the proximity of the pest itself. Since the viability of the organism may be vital, the zone of desired activity needs to be considered during the development phase of a microbial pesticide. 

The influence of room transverse cross-section configuration on airflow patterns created by air jets supplied through round nozzles in proximity to the ceiling was studied by Baharev and Troyanovsky and Nielsen (see Fig. 7.37). Based on experimental data, they concluded that when the room width B is less than 3.5H, the jet attaches to the ceiling and spreads, filling the whole width of the room in the manner of a linear jet. The reverse flow develops under the jet. When B > 4H, the reverse flow also develops along the jet sides. Baharev and Troyanovsky indicated that air temperature and velocity distribution in the occupied zone is more uniform when the jet develops in the upper zone and the occupied zone is ventilated by the reverse flow. Thus, they proposed limiting room width to 3-3.5H,. 

Key indicators of alteration and proximity to ore are increased K2O (particularly in the shale component) near complete loss of Na20 increased FeO (particularly in the siltstone-sandstone component) and increased CO2 in shale. These changes reflect the development of iron carbonate (siderite and ankerite) by carbonate introduction and some alteration of existing calcic carbonate in siltstone-sandstone samples. Destruction of albite, absence of chlorite and increased abundance of muscovite due to potassic alteration, are the other major mineral alteration effects in the altered host rocks. Trace elements enriched in the primary dispersion zone are Zn, Pb, Ag, Sb, As, Rb, and TI. Antimony provides the most consistent and extensive trace element dispersion halo around the deposit and is also preserved in most of... 

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