A plea for consideration of ecological validity in the experimental psychology of mental retardation: a guest editorial

The point was raised that, despite considerable experimental effort, laboratory research concerning learning, memory, and cognition, more generally, has not produced a very remarkable increase in our understanding of retarded behavior. Our principal contention in this paper is that the experimental psychology of mental retardation, while basically seeking causal relations between theoretical constructs and retarded behavior, is suffering from some metatheoretical and methodological shortcomings. These include, basically, a prevalent failure to consider the ecological aspects of the phenomenon of mental retardation. Implications of ecological validity are important with respect to the basis upon which subjects are selected for experimentation, the rationale underlying manipulation of independent variables, the choice of dependent variables, and the definition of the boundaries that limit generalizations. Some suggestions were offered for the purpose of guiding experimental research toward more meaningful and socially relevant goals.     

Contemporary theories of depression: critique and comparison

Three theoretical viewpoints have dominated the recent empirically oriented literature on depression: A. Beck's (see PA, Vol 53:7512) cognitive view, M. Seligman's (see PA, Vol 53:7618) helplessness model, and P. M. Lewinsohn's (see PA, Vol 53:7587) theory implicating a low rate of response-contingent reinforcement. In this paper, each theory is evaluated individually in terms of its empirical support and adequacy as a theory, and the theories are contrasted and compared with one another. Special attention is given to recent studies not discussed in the theorists' major summary papers and to empirical findings whose relevance to a particular theory has not previously been noted. Although there is reason to believe that any or all of the elements suggested by the three theorists—perception, control, and rate of reinforcement—are of import in depression, none has been proven to be a necessary antecedent of depressive episodes. (3 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Expression of alpha-D-mannosidase in man-hamster somatic cell hybrids

Two types of alpha-D-mannosidase isozymes are present in human white blood cells, human diploid fibroblasts, and HeLa cells. One of these (the S isozyme) constitutes the major alpha-D-mannosidase of the human cells, has a pH optimum of 4.4, and is associated with lysosomes. The other (the F isozyme) is most active at pH 6, is acid labile, and is located in the soluble portion of the cytoplasm. The expression of human lysosomal alpha-D-mannosidase was examined in man-hamster hybrid clones, and was found to be concordant with that of phosphohexose isomerase in 54 of 55 primary clones. A locus specifying human lysosomal alpha-D-mannosidase has therfore been assigned to chromosome 19.     

The measurement of urethral resistance and mural tension using simple programmable modules

The theory of urethral resistance and the derivation or mural tension have been discussed. A method for the continuous calculation and presentation of these parameters has been described. Urethral resistance and mural tensions are altered by the presence of bladder outflow obstruction and have been shown to return to normality after the obstruction is removed.     

Ion Implantation of Pb0.8Sn0.2Te

The ion implantations of many ions into single crystal epitaxial films of Pb0.8Sn0.2Te have been evaluated. Because of the wide spectrum of results, only those of the two most promising ions, S+ and In+, are presented. The S+ ions produced a p-type layer in Pb0.8Sn0.2Te. After a suitable post implant anneal In+ ions produced an n-type layer in p-type Pb0.8 Sn0.2Te. The In+ implants were used to produce detector arrays, while the S+ implants produced complete conversion of 4500 ? films.