Studies have failed to yield definitive evidence for the existence and/or role of well-defined chaotic attractors in real brain systems. Tsuda's transients stabilized on unstable manifolds of unstable fixed points using mechanisms similar to Ott's algorithmic “control of chaos” are demonstrable. Grebogi's order in preserving “strange nonchaotic” attractor with fractal dimension but Lyapounov is suggested for neural network tasks dependent on sequence.

Motor processes cannot be modeled by a single (unified) model. Instead, a number of models at different levels of description are needed. The concepts of control and control variable only make sense at the functional level. A clear distinction must be made between external models and internal models. General Systems Theory provides the framework for a proper treatment of these issues.

Alpha‐fetoprotein (AFP)AFP, alpha‐fetoprotein; T3R, thyroid hormone (triiodothyronine) receptor; RAR, retionic acid receptor; erbA, putative thyroid hormone receptor proto‐oncogene products; VDR, vitamin D receptor; MR, mineralocorticoid receptor; GR, glucocorticoid receptor; PR, progesterone receptor; AR, androgen receptor; HRE, hormone response element on DNA; RXR, retionic‐X‐receptor; RAP, receptor auxiliary (accessory) proteins; E, estrogen. is a tumor‐associated fetal marker, associated both with tumor growth and with birth defects. AFP, whose precise function is unknown, has been classified as belonging to a protein superfamily together with (...) albumin and vitamin D‐binding (Gc) protein. AFP has been shown to bind various ligands in vitro including fatty acids, estrogens, thyroid hormones and retinoic acids. The steroid/thyroid nuclear receptor superfamily of proteins has recently become a major focus of biomedical investigation regarding regulation of gene expression. These receptors are thought to bind to DNA‐hormone response elements (HRE) that affect growth, development, differentiation, reproduction and homeostasis. The HREs are known to share DNA sequences with the various members of the nuclear receptor superfamily. In the present report, the possibility of a leucine‐zipper dimerization (heptad) motif in the carboxy‐terminal third domain of both rodent and human AFP is postulated. The presence of nine such hydrophobic repeats in the third domain of the AFP molecule mimics the heptad dimerization repeats found in the retinoic acid, thyroid, e‐erbA and other members of the nuclear receptor superfamily. Computer analysis revealed that the most conservative matching occurred between AFP and the retinoic acid class of receptors. However, other superfamily members displayed 40–60% homology with 5 of 9 AFP heptads. These findings could provide a possible mechanism for explaining the growth‐regulatory properties (both inhibition and enhancement) that have been ascribed to AFP in the last decade. (shrink)

Professor Frankena mentions me as one of the participants in what he calls the Movement in moral philosophy, and I think he is right; I was so moving, or being moved along among others, ten years or so ago, and I think I find myself still inclined to so move, while recognising with regret, when I come to look back at it, that, as he courteously observes, “what such writers say is not as clear as one would like.” I embark (...) on commenting upon his lectures with considerable trepidation, however, for the reason that, while his own writing surely is as clear as one could reasonably hope for, I have had great difficulty in figuring out what exactly it is in the Movement that he substantially dissents from, and have the lurking suspicion that there may be something that I have just failed to see. Tentatively, though, I tend to think that the root of my difficulty has been that he offers, in opposition to the Movement, an account of these matters that is really, in the end, not intelligible; and my main task in this commentative piece will be to try to explain why I think that. (shrink)

Philosophy and philosophical workers play very important roles in the socialist society of the People's Republic of China. No longer is philosophy treated as an object of speculation; nor is it regarded as merely a method of applying theory. It is now considered to be a process of learning from the practical experience of the masses, a process of enriching the concrete life of the people, and a process of solving specific problems in remaking society and changing the world. Briefly (...) speaking, philosophy plays the important role of eliminating alienation and the possibility of alienation among men. On this basis, philosophical workers, like other intellectuals, are urged to unite with and learn from the masses — the industrial workers and the peasants. Many writings have focused on this Maoist point, which is exemplified in this issue by Kuan Feng's article. From this point of view, traditional philosophy, which fails to eliminate alienation and which in fact tends to create and justify alienation as defined by Marxist and Maoist ideology, is subjected to severe criticism. (shrink)