From Development To Evolution: The Re-Establishment Of The Alexander Kowalevsky Medal

The Saint Petersburg Society of Naturalists has reinstated the Alexander O. Kowalevsky Medal. This article announces the winners of the first medals and briefly reviews the achievements of A.O. Kowalevsky,the Russian comparative embryologist whose studies on amphioxus, tunicates and germ layer homologies pioneered evolutionary embryology and confirmed the evolutionary continuity between invertebrates and vertebrates. In re-establishing this international award, the Society is pleased to recognize both the present awardees and the memory of Kowalevsky, whose work pointed to that we now call evolutionary developmental biology

Вычислительный подход к построению биологии

According to some critics, if biology is a kind of reverse engineering for the nature, it is quite poorly prepared for the task. Thus, the issue is more likely with its ontology. Multiple hypotheses and conjectures found in papers on methodological issues claim that living systems should be viewed as complex networks of signal-transmitting paths, both neural and non-neural, that feature modularity and feedback circuits and are prone to emergent properties and increasing complexity. If so, we are on the eve of a new stage in computer models development where not only computers are used to emulate life, but life itself is construed as a complex network of interacting natural computers. In 2002, Yuri Lazebnik used a salient and profound metaphor to clarify the main theoretical shortage that keeps biology from being a unified and deductively consistent science modeled after physics. Asking if a biologist could fix a broken radio, he revealed that what is missing there is a uni-fied formal language for describing ultimate elements of living devices together with their typical combinations, as it is commonly done in radio engineering. I specify in the paper that what Lazebnik means by a “formal language” is not a language of propositions about the world, i.e., of asserting some states of affairs, but rather a language of listing relevant types of objects and their relations. I refer to it as a domain ontology. A theory needs another language to describe actual states of affairs, which most probably shall be mathematical to be able to represent complicated natural structures in their detail. Then I touch on the popular views, according to which a domain ontology is inferred by a theory prop-er. The history of science shows that true theories that are viable today were often paired with now abandoned ontologies, like that of Caloric or Phlogiston. I suggest that a theory does not infer its on-tology, but rather is interpreted thereupon, being inferentially independent of it. I also review some historically important attempt to mathematize the knowledge of life. I mention Alan Turing’s article on morphogenesis where he used some linear differential equations to explain emergence of complexity from homogeneity. Then I briefly touch on works Nicolas Rashevsky whose theories provided inspira-tion to the inventors of artificial neural networks and allowed for abundant use of different mathemati-cal tools by his disciple Robert Rosen in his study of metabolism. Closer to nowadays, various compu-tational theories in biology have emerged. Some of them treat protein combinations as networks of signal-transmitting pathways that can store and process information. Moreover, in unicellular organ-isms, protein-based circuits replace the whole of the nervous system as a behavior-controlling network. Other theories propose a view, in which an organism is construed as a system of modules connected with protocols, of interfaces. A domain ontology like this may considerably simplify the task of scien-tific description. A special attention is paid to applications of the known free-energy (minimization) principle to the life science matters, as it has initially intended to explain issues of cognitive science. In general, within this view, for an organism to survive is to minimize its thermodynamic potential ener-gy, for which purpose the living being as a whole, and all its subsystems, must constantly produce statistical models of environment that are constantly updated with incoming data. Some strong Bayesi-an mathematics combine with this ontology to claim the whole enterprise as the most prominent uni-versal theory of complex developing systems nowadays. As a general output of the survey, I propose a computational methodological approach of doing biology based on the famous Marr’s three-level view on computational systems together with the necessity of identifying elementary nodes, of which living systems are composed. Such an approach may, as I hope, generate a set of competing theories that will eventually help biologists to fix their “radio”

Социальная онтология: время вычислений

Discussions on the alleged methodological specificity of social knowledge are fueled to not the least extent by a kind of retarded position of the latter against technological advance-ments of natural and information science based on exact methods and formal or quantitative languages. It is more or less obvious that applicability of exact scientific methods to social disciplines is highly dependent on a chosen conception of social reality, i. e., on social on-tology. In the article, the author critically approaches the ontological views of Tony Lawson and proposes a computational view on social ontology that is supposed to eliminate some in-ternal contradictions of Lawson’s realist conception

Zero curvature representation for a new fifth-order integrable system

In this brief note we present a zero-curvature representation for one of the new integrable system found by Mikhailov, Novikov and Wang in nlin.SI/0601046.Comment: 2 pages, LaTeX 2e, no figure

Characteristics of Radiation of a round Waveguide through a Flat Homogeneous Heat Shield

The problem of obtaining an analytical description of the radiation characteristics of a circular waveguide closed by a flat homogeneous dielectric plate is solved. The radiation characteristics include: the radiation field; the conductivity of the aperture radiation; and the fields of surface, flowing, and side waves, as well as energy characteristics. In such a statement, a strict solution of Maxwell’s equations is required. The paper uses the method of integral transformations and the method of eigenfunctions. In this case, the assumption is used that the electrical parameters of the dielectric plate (thermal protection) and the geometric dimensions do not depend on time. The relations describing the directional diagram of a circular waveguide with dielectric thermal protection and taking into account the electrical parameters of thermal protection and its thickness are obtained. Expressions are also obtained for the fields of lateral, surface, and outflow waves, from which it is possible to calculate the power taken away by these fields. Numerical calculations were made for some of the obtained relations. The results showed that the power of the side waves is zero. It also follows from the calculations that the radiation field of surface and flowing waves is absent, that is, their contribution to the directional diagram is not

Simulation of flow around oscillating rotor blade section with aeroelastic flap

Flows around rotor blade sections equipped with active flaps with a degree of freedom in the flap deflection angle are considered in this paper. Results for oscillating flaps are presented. The resultant flap motion was found to couple with the unsteady air loads for cases of blade section in oscillatory translation

Two ground-state modifications of quantum-dot beryllium

Exact electronic properties of a system of four Coulomb-interacting two-dimensional electrons in a parabolic confinement are reported. We show that degenerate ground states of this system are characterized by qualitatively different internal electron-electron correlations, and that the formation of Wigner molecule in the strong-interaction regime is going on in essentially different ways in these ground states.Comment: 5 pages, incl 5 Figures and 2 Table

X-Ray Fluorescence Determination of Trace Gold in an Ion-Exchange Resin

The use of portable X ray optics with a secondary radiator in the determination of trace gold in an ion exchange resin within the mass fraction range of 1–50 ppm is described. It is shown that the secondary radiator design with primary radiation filtering allows one to determine trace gold in an ion exchange resin when the mass fraction of gold is lower than 1 ppm

Enhanced graphene nonlinear response through geometrical plasmon focusing

We propose a simple approach to couple light into graphene plasmons and focus these excitations at focal spots of a size determined by the plasmon wavelength, thus producing high optical field enhancement that boosts the nonlinear response of the material. More precisely, we consider a graphene structure in which incident light is coupled to its plasmons at the carbon edges and subsequently focused on a spot of size comparable to the plasmon wavelength. We observe large confinement of graphene plasmons, materializing in small, intense focal spots, in which the extraordinary nonlinear response of this material leads to relatively intense harmonic generation. This result shows the potential of plasmon focusing in suitably edged graphene structures to produce large field confinement and nonlinear response without involving elaborated nanostructuring.Peer ReviewedPostprint (published version

Representations of sl(2,?) in category O and master symmetries

We show that the indecomposable sl(2,?)-modules in the Bernstein-Gelfand-Gelfand category O naturally arise for homogeneous integrable nonlinear evolution systems. We then develop a new approach called the O scheme to construct master symmetries for such integrable systems. This method naturally allows computing the hierarchy of time-dependent symmetries. We finally illustrate the method using both classical and new examples. We compare our approach to the known existing methods used to construct master symmetries. For new integrable equations such as a Benjamin-Ono-type equation, a new integrable Davey-Stewartson-type equation, and two different versions of (2+1)-dimensional generalized Volterra chains, we generate their conserved densities using their master symmetries