Rapid photoresponses in the retina and their relevance to vision research

Abstract— An intense short flash stimulus gives rise to transient electrical responses of about a millisecond duration from vertebrate and some invertebrate retinas. Some aspects of these rapid retinal responses are reviewed. It is concluded that they probably represent electrical expressions of photochemical events or events closely associated with photochemistry of visual pigment, that they do not represent the excitation of the photoreceptors per se, and that still unidentified, silent processes intervene between them and the excitation of the photo-receptor. The fact that photochemical events produce movements of charges, which result in these responses, is of interest in itself. Moreover, these responses present us with a relatively simple and effective technique for probing the role of visual pigment in visual excitation in the intact retina.     

Superfield formulation of the simplest three-dimensional gauge theories and conformal supergravities

Tashkent State University. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 77, No. 1, pp. 97–106, October, 1988.     

Minor and Trace Sterols in Marine Invertebrates. XII. Occurrence of 24 (R + S)-isopropenylcholesterol, 24 (R + S)-methylcholesta-5, 25-dien-3β-ol,and 24 (R + S)-methylcholesta-7, 25-dien-3β-ol in the caribbean sponge,Verongia cauliformis

In addition to the two new sterols verongulasterol 11 and 25-dehydroaplysterol 13 of Verongia cauliformis³), which were reported earlier [2] [3], the minor and trace sterols of this sponge include five new sterols listed in the title (with the exception of the known 24 S-methyl-cholesta-5, 25-dien-3β-ol (codisterol, 1b ). The isolation of the 24(R)-epimer of codisterol is of interest, as this compound is a possibly biosynthetic precursor for aplysterol 12 , 25-dehydroaplysterol 13 , and verongulasterol 11 (all 24R) which occur in the same sponge [2]. A partial synthesis from fucosterol ( 4 ) of 24 (R + S)-isopropenylcholesterol ( 9 ), and of 24-isopropylcholesterol ( 10 ) is described.     

Axial anomaly and chiral symmetry breaking in Schwinger model: A canonical approach

We use a recently introduced canonical surface formalism, to study the problem of chiral symmetry breaking in the Schwinger model. We perfect the parallel between QCD₄ and QED₂ in this respect.     

Quantitative isotope enrichment in a thermal diffusion arrangement

The problem of enrichment of a gas sample by a definite factor is considered. It occurs, for example, when the radiocarbon dating method is to be extended to higher ages. The case of a thermal diffusion column with finite reservoirs at both ends is investigated and the decisive benefit of a high separation factor for the sufficient knowledge and reproducibility of the enrichment factor is pointed out. The relation between the factors as well as their temporal behaviour is developed in two ways: Simple formulae with physical evidence are adapted to make allowance for the content of the column itself, and then verified by deriving the exact isotope distribution from the partial differential equation.     

Synthesis of 1,3-diaryl-2,2-dichloroethyleneimines

1,3-Diaryl-2-dichloroethyleneimines were synthesized by the reaction of aromatic Schiff bases with chloroform in the presence of potassium tert-butoxide. Several properties of these compounds were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 180–181, February, 1972.     

Temperature dependence of effective charge in dipole model of ferroelectrics

Combining the concept of the effective charge in the dipole model with the statistical theory of ferroelectricity proposed previously, the temperature dependence of the effective charge is evaluated numerically for various values of dipole interaction.