Avery’s et al. ’s 1944 paper provides the first direct evidence of DNA having gene-like properties and marks the beginning of a new phase in early molecular genetics (with a strong focus on chemistry and DNA). The study of its reception shows that on the whole, Avery’s results were immediately appreciated and motivated new research on transformation, the chemical nature of DNA’s biological specificity and bacteria genetics. It shows, too, that initial problems of transferring transformation to other systems and prominent (...) criticism of its results nurtured skepticism. Avery’s experiment was downplayed and neglected particularly by many of those scientists who worked in the new fields of biochemical and biophysical genetics, genetic phage, and TMV research. This was not due to the fact that the implications of the paper could not be connected to generally accepted knowledge. Contrary to a widespread belief, the assumed uniformity of DNA as opposed to proteins was not used as an argument against the validity of Avery’s et al.’s finding. The indifference rather reflected, among other things, the disciplinary gap between the chemically oriented microbiologists and the old and new geneticists who remained committed to genetic and physical methods (in particular x-ray studies) and clung to the assumption that proteins were the sole carriers of biological specificity. The responses to Avery’s et al.’s paper show how different research interests in the areas between microbiology, genetics, and biochemistry interacted with the prejudices, dogmas, individual farsightedness or short-sightedness, and scientific authority during a pivotal period of early molecular biology. (shrink)

This paper offers a critique of the Bayesian interpretation of quantum mechanics with particular focus on a paper by Caves, Fuchs, and Schack containing a critique of the “objective preparations view” or OPV. It also aims to carry the discussion beyond the hardened positions of Bayesians and proponents of the OPV. Several claims made by Caves et al. are rebutted, including the claim that different pure states may legitimately be assigned to the same system at the same time, and the (...) claim that the quantum nature of a preparation device cannot legitimately be ignored. Both Bayesians and proponents of the OPV regard the time dependence of a quantum state as the continuous dependence on time of an evolving state of some kind. This leads to a false dilemma: quantum states are either objective states of nature or subjective states of belief. In reality they are neither. The present paper views the aforesaid dependence as a dependence on the time of the measurement to whose possible outcomes the quantum state serves to assign probabilities. This makes it possible to recognize the full implications of the only testable feature of the theory, viz., the probabilities it assigns to measurement outcomes. Most important among these are the objective fuzziness of all relative positions and momenta and the consequent incomplete spatiotemporal differentiation of the physical world. The latter makes it possible to draw a clear distinction between the macroscopic and the microscopic. This in turn makes it possible to understand the special status of measurements in all standard formulations of the theory. Whereas Bayesians have written contemptuously about the “folly” of conjoining “objective” to “probability,” there are various reasons why quantum-mechanical probabilities can be considered objective, not least the fact that they are needed to quantify an objective fuzziness. But this cannot be appreciated without giving thought to the makeup of the world, which Bayesians refuse to do. Doing this on the basis of how quantum mechanics assigns probabilities, one finds that what constitutes the macroworld is a single Ultimate Reality, about which we know nothing, except that it manifests the macroworld or manifests itself as the macroworld. The so-called microworld is neither a world nor a part of any world but instead is instrumental in the manifestation of the macroworld. Quantum mechanics affords us a glimpse “behind” the manifested world, at stages in the process of manifestation, but it does not allow us to describe what lies “behind” the manifested world except in terms of the finished product—the manifested world, for without the manifested world there is nothing in whose terms we could describe its manifestation. (shrink)

Книга рассчитана на студентов, аспирантов, преподавателей высших и средних учебных заведений, всех интересующихся данными исследованиями.

Three early 20th-century attempts at unifying separate areas of biology, in particular development, genetics, physiology, and evolution, are compared in regard to their success and fruitfulness for further research: Jacques Loeb’s reductionist project of unifying approaches by physico-chemical explanations; Richard Goldschmidt’s anti-reductionist attempts to unify by integration; and Sewall Wright’s combination of reductionist research and vision of hierarchical genetic systems. Loeb’s program, demanding that all aspects of biology, including evolution, be studied by the methods of the experimental sciences, proved highly (...) successful and indispensible for higher level investigations, even though evolutionary change and properties of biological systems up to now cannot be fully explained on the molecular level alone. Goldschmidt has been appraised as pioneer of physiological and developmental genetics and of a new evolutionary synthesis which transcended neo-Darwinism. However, this study concludes that his anti-reductionist attempts to integrate genetics, development and evolution have to be regarded as failures or dead ends. His grand speculations were based on the one hand on concepts and experimental systems that were too vague in order to stimulate further research, and on the other on experiments which in their core parts turned out not to be reproducible. In contrast, Sewall Wright, apart from being one of the architects of the neo-Darwinian synthesis of the 1930s, opened up new paths of testable quantitative developmental genetic investigations. He placed his research within a framework of logical reasoning, which resulted in the farsighted speculation that examinations of biological systems should be related to the regulation of hierarchical genetic subsystems, possibly providing a mechanism for development and evolution. I argue that his suggestion of basing the study of systems on clearly defined properties of the components has proved superior to Goldschmidt’s approach of studying systems as a whole, and that attempts to integrate different fields at a too early stage may prove futile or worse. © 2011 Elsevier Inc. (shrink)

The processing of information within the retino-tectal visual system of amphibians is decomposed into five major operational stages, three of them taking place in the retina and two in the optic tectum. The stages in the retina involve (i) a spatially local high-pass filtering in connection to the perception of moving objects, (ii) separation of the receptor activity into ON- and OFF-channels regarding the distinction of objects on both light and dark backgrounds, (iii) spatial integration via near excitation and far-reaching (...) inhibition. Variation of the spatial range of excitation and inhibition allows to account for typical activities observed in a variety of classes of retina ganglion cells.Mathematical description of the operations in the tectum opticum include (i) spatial summation of retinal output (mainly of class-2 and class-3 retina ganglion cells), and (ii) direct or indirect lateral inhibition between tectal cells. In the computer simulation, first the output of the mathematical retina model is computed which, then, is used as the input to the tectum model. The full spatio-temporal dynamics is taken into account. (shrink)