A model of attention-guided visual perception and recognition.

A model of visual perception and recognition is described. The model contains: (i) a low-level subsystem which performs both a fovea-like transformation and detection of primary features (edges), and (ii) a high-level subsystem which includes separated 'what' (sensory memory) and 'where' (motor memory) structures. Image recognition occurs during the execution of a 'behavioral recognition program' formed during the primary viewing of the image. The recognition program contains both programmed attention window movements (stored in the motor memory) and predicted image fragments (stored in the sensory memory) for each consecutive fixation. The model shows the ability to recognize complex images (e.g. faces) invariantly with respect to shift, rotation and scale.

[Intramolecular hydrogen bonds and conformation of the lincomycin molecule in organic solvents]. / Vnutrimolekuliarnye vodorodnye sviazi i konformatsiia molekuly linkomitsina v organicheskikh rastvoriteliakh.

IR spectra (1600-1800 and 3000-3650 cm-1) of lincomycin base solutions in inert (CCl4 and C2Cl4), proton acceptor (dioxane, dimethylsulfoxide and triethyl amine) and proton donor (CHCl3, CD3OD and D2O) solvents were studied. Analysis of the concentration and temperature changes in the spectra revealed that association in lincomycin in the inert solvents was due to intramolecular hydrogen linkage involving amide and hydroxyl groups. Disintegration of the associates after the solution dilution and temperature rise was accompanied by formation of intramolecular bonds stabilizing the stable conformation structure of the lincomycin molecule. The following hydrogen linkage in the conformation was realized: NH...N (band v NH...N at 3340 cm-1), OH...O involving the hydroxyl at C-7 and O atoms in the D-galactose ring (band v OH...O at 3548 cm-1), a chain of the hydrogen bonds OH...OH...OH in the lincomycin carbohydrate moiety (band v OH...O at 3593 cm-1 and v OH of the end hydroxyl group at 3625 cm-1). Bonds NH and C-O of the amide group were located in transconformation. Group C-O did not participate in the intramolecular hydrogen linkage.

[Tissue changes in the intervertebral disk following hypokinesia in rats of different ages]. / Izmeneniia tkanei mezpozvonochnogo diska posle gipokinezii u krys raznogo vozrasta.

Effect of various duration of hypokinesia on structural-metabolic characteristics of the lumbar vertebral segment has been studied in Wistar rats. Hypokinesia results in certain morphological changes of the spongy bone and tissues of the intervertebral disk, demonstrating as delayed processes of ossification, disturbed course of organization into bundles of collagenous fibers of the fibrous ring, widening of the nucleus pulposus zone. Polarization-optical investigations reveal some disturbances in the macro-molecular organization of collagen, expressed as decreasing degree of its refraction and as redistribution of glycosaminoglycans towards increasing sulfated keratan sulfates.