Petrography lower if wholly or partly vitreous. The specific gravity of the more common rocks range from about 2.5 to 3.2. Archaeologists use petrography to identify mineral components in pottery. This information ties the artifacts to geological areas where the raw materials for the pottery were obtained. In addition to clay, potters often used rock fragments, usually called "temper" or "aplastics", to modify the clay's properties. The geological information obtained from the pottery components provides insight into how potters selected and used local and non-local resources. Archaeologists are able to determine whether pottery found in a particular location was locally produced
The Gothenburg Study of Children with DAMP The Gothenburg Study of Children with DAMP The Gothenburg Study of Children with DAMP was a study of six-year-old children in Gothenburg, Sweden that began in 1977. The purpose was to find out what proportion of the children had Deficits in Attention, Motor control and Perception (DAMP), formerly known as Minimal Brain Disorder (MBD), and to follow the development of that group over the years. The results and discussions have been published in four dissertations and approximately 30 scientific papers. The first phase of the study was designed mainly by Christopher Gillberg and Peder Rasmussen. Initially, preschool teachers in all