Algebraic Integration of Sigma Model Field Equations

We prove that the dualization algebra of the symmetric space coset sigma model is a Lie algebra and we show that it generates an appropriate adjoint representation which enables the local integration of the field equations yielding the first-order ones.Comment: 27p

A low-cost hyperspectral scanner for natural imaging and the study of animal colour vision above and under water

Hyperspectral imaging is a widely used technology for industrial and scientific purposes, but the high cost and large size of commercial setups have made them impractical for most basic research. Here, we designed and implemented a fully open source and low-cost hyperspectral scanner based on a commercial spectrometer coupled to custom optical, mechanical and electronic components. We demonstrate our scanner's utility for natural imaging in both terrestrial and underwater environments. Our design provides sub-nm spectral resolution between 350-950 nm, including the UV part of the light spectrum which has been mostly absent from commercial solutions and previous natural imaging studies. By comparing the full light spectra from natural scenes to the spectral sensitivity of animals, we show how our system can be used to identify subtle variations in chromatic details detectable by different species. In addition, we have created an open access database for hyperspectral datasets collected from natural scenes in the UK and India. Together with comprehensive online build- and use-instructions, our setup provides an inexpensive and customisable solution to gather and share hyperspectral imaging data

Integrals of monomials over the orthogonal group

A recursion formula is derived which allows to evaluate invariant integrals over the orthogonal group O(N), where the integrand is an arbitrary finite monomial in the matrix elements of the group. The value of such an integral is expressible as a finite sum of partial fractions in $N$. The recursion formula largely extends presently available integration formulas for the orthogonal group.Comment: 9 pages, no figure

Conductance matrix of multi terminal semiconductor devices with edge channels

This paper presents a method for determining the conductance matrix of multi terminal semiconductor structures with edge channels. This method appears to be applied within frameworks of the ordinary Landauer - uttiker formalism for the carrier transport analysis in the regime of both the quantum Hall Effect and the quantum spin Hall Effect. The proposed method proves to take into account principally the contribution of the probes resistance in the formation of the matrix conductance elements. Finally, the possibilities of the practical application of this method to develop new versions of analog cryptographic devices are discussed.Comment: 28 pages, 4 figures, Language - Russia

Full versus first stage replica symmetry breaking in spin glasses

A short survey is presented on spin--glass--like states characteristics in complex nonmagnetic systems. We discuss the interplay of the interaction structure and symmetry with the classification scenarios of the replica symmetry breaking. It is shown that the kind of the transition to the nonergodic state depends not only on the presence or absence of the reflection symmetry but on the number of interacting operators and their individual characteristics.Comment: 5 pages, 2 figure

Factors modifying the response of large animals to low-intensity radiation exposure

In assessing the biological response to space radiation, two of the most important modifying factors are dose protraction and dose distribution to the body. Studies are reported in which sheep and swine were used to compare the hematology and lethality response resulting from radiation exposure encountered in a variety of forms, including acute (high dose-rate), chronic (low dose-rate), combinations of acute and chronic, and whether received as a continuous or as fractionated exposure. While sheep and swine are basically similar in response to acute radiation, their sensitivity to chronic irradiation is markedly different. Sheep remain relatively sensitive as the radiation exposure is protracted while swine are more resistant and capable of surviving extremely large doses of chronic irradiation. This response to chronic irradiation correlated well with changes in radiosensitivity and recovery following an acute, sublethal exposure