: The transplantation of adult human neural stem cells into prenatal non-humans offers an avenue for studying human neural cell development without direct use of human embryos. However, such experiments raise significant ethical concerns about mixing human and nonhuman materials in ways that could result in the development of human-nonhuman chimeras. This paper examines four arguments against such research, the moral taboo, species integrity, "unnaturalness," and human dignity arguments, and finds the last plausible. It argues that the transfer of human (...) brain or retinal stem cells to nonhuman embryos would not result in the development of human-nonhuman chimeras that denigrate human dignity, provided such stem cells are dissociated. The article provides guidelines that set ethical boundaries for conducting such research that are consonant with the requirements of human dignity. (shrink)

In the present paper some formal aspects of the hypothesis-directed stage of medical diagnosis are studied and an algorithm of the diagnostic problem solving process is described. A given field of medical knowledge is represented by a pair of graphs. The sentences describing observed symptoms and signs constitute the data on which the algorithm is based. In the first step, the set of true judgments is determined and the hypotheses which are impossible in a given situation are rejected. In consequence (...) the model of knowledge is modified and working hypotheses are chosen. Further steps consist in selection of hypotheses in view of testing. The set of expected symptoms is determined and these are classified according to their diagnostic value. The process ends when the conditions of arriving at a useful solution of a given problem are fulfilled. The description of the algorithm is based on a clinical example. The model aims at reflecting some of the most important structural features of the diagnosis and does not embrace the probability evaluation problems. (shrink)

The Presocratics in the Thought of Martin Heidegger. By Korab-Karpowicz W. Julian..).