A new probabilistic model describing the fatigue crack growth with retardation due to random overloads is developed. First, a crack growth equation is formulated based upon the Flber law, where a concept of retardation factor is introduced to quantify the retardation effect. Next, a new approach is discussed for describing the temporal variation of the retardation factor by the use of a system ...

The relation of muscular activity to mental development, recognized as it has been from the very beginning of modern psychology, teaches us that kinesthetic, i. e., motor, images are more important than visual or auditory images, and that a greater part of the sensations bringing about mental development are excited through motor activities. This is a fundamental truth, and the leaders of to-da...

In this paper, we respond to a 1992 study by Mathias and Nettelbeck in which, using exploratory factor analysis, they argued that the structure of intelligence in persons with mental retardation deviates from the model previously proposed by Greenspan. Applying the LISREL method of confirmatory factor analysis to Mathias and Nettelbeck's original correlation matrix, we found the Greenspan model...

Insulin-like growth factor-I (IGF-I) is essential for normal growth; igf-1 gene mutations are associated with extreme growth retardation in mice and, very rarely, in humans. The relative contributions of tissue vs. endocrine (hepatic) IGF-I to the regulation of growth has been a fundamental question. New gene targeting technologies are providing answers for these questions.

background and purpose: birth of a mentally retarded child is a significant challenge in every family and is associated with the possibility of parental stress and depression. this study aimed to evaluate the self-concept of mothers with educable mentally retarded (emr) children. methods: this cross-sectional study was conducted on 40 mothers with emr children in the only special primary school...

Fragile X syndrome, a common form of inherited mental retardation, is caused by the loss of fragile X mental retardation protein (FMRP). We have previously demonstrated that dFmr1, the Drosophila ortholog of the fragile X mental retardation 1 gene, plays a role in the proper maintenance of germline stem cells in Drosophila ovary; however, the molecular mechanism behind this remains elusive. In ...