Conformal representations of the general scalar-tensor theory and cosmological models

The article is a review of cosmological models describing the accelerated expansion of the Universe built by using various conformal representations of the modified Jordan-Brans-Dicke (JBD) theory.     

Perceptual sharpening in the developing rat.

Studied the development of perceptual sharpening in 4 experiments with 514 Sprague-Dawley rats using the heart rate orienting response ([HROR] marked cardiac deceleration to novel stimuli) as the dependent measure. Preweanling Ss either 16–17 or 19–20 days of age were habituated to a 1,600-Hz tone over 15 trials. On Trial 16, the stimulus frequency was changed to 1 of 7 tones distributed on either side of the habituated stimulus. Analysis of the HROR showed that 16–27 day old Ss failed to respond to any of the new frequencies, which indicated generalization of habituation to the auditory stimuli within the frequency range studied. In marked contrast, 19–20 day old Ss displayed an HROR proportional to the difference between the habituated and the test stimuli. These age-related differences were not due to differences in sensitivity to the test stimuli, effector fatigue, or inability to discriminate between the test stimuli. Results indicate that perceptual sharpening develops relatively rapidly in rats and that perceptual sharpening, stimulus detection, and stimulus discrimination follow separate ontogenetic time courses. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Robust uniform triangulation algorithm for computer aided design

This paper presents a new robust uniform triangulation algorithm that can be used in CAD/CAM systems to generate and visualize geometry of 3D models. Typically, in CAD/CAM systems 3D geometry consists of 3D surfaces presented by the parametric equations (e.g. surface of revolution, NURBS surfaces) which are defined on a two dimensional domain. Conventional triangulation algorithms (e.g. ear clipping, Voronoi-Delaunay triangulation) do not provide desired quality and high level of accuracy (challenging tasks) for 3D geometry. The approach developed in this paper combines lattice tessellation and conventional triangulation techniques and allows CAD/CAM systems to obtain the required surface quality and accuracy. The algorithm uses a Cartesian lattice to divide the parametric domain into adjacent rectangular cells. These cells are used to generate polygons that are further triangulated to obtain accurate surface representation. The algorithm allows users to control the triangle distribution intensity by adjusting the lattice density. Once triangulated, the 3D model can be used not only for rendering but also in various manufacturing and design applications. The approach presented in this paper can be used to triangulate any parametric surface given in S(u,v) form, e.g. NURBS surfaces, surfaces of revolution, and produces good quality triangulation which can be used in CAD/CAM and computer graphics applications.     

State and Output Feedback Certainty Equivalence M‐MRAC for Systems with Unmatched Uncertainties

The paper presents a certainty equivalence indirect adaptive control design method for parametric strict feedback nonlinear systems of any relative degree with unmatched uncertainties in state and output feedback settings. The approach is based on the parameter identification (estimation) model, which is completely separated from the control design and is capable of producing parameter estimates as fast as the computing power allows. It is shown that the system's input and output tracking errors can be systematically decreased by the proper choice of the design parameters.     

Using Pseudoorthogonal Signals to Reduce Noise Level in Ultrasound Testing of Highly Absorptive Materials

Russian Journal of Nondestructive Testing - To increase the signal-to-noise ratio when testing materials with a high level of absorption, it has been proposed to use complex signals, formed on the...     

Direct Imprinting of Porous Silicon via Metal‐Assisted Chemical Etching

Conventional lithographical techniques used for bulk semiconductors produce dramatically poor results when used for micro and mesoporous materials such as porous silicon (PS). In this work, for the first time, a high‐throughput, single‐step, direct imprinting process for PS not involving plastic deformation or high‐temperature processing is reported. Based on the underlying mechanism of metal‐assisted chemical etching (MACE), this process uses a pre‐patterned polymer stamp coated with a noble metal catalyst to etch PS immersed in an HF‐oxidizer mixture. The process not only overcomes the difficulties in patterning PS but it does so with a stamp that may be reused multiple times depending on its chemical and mechanical degradation. The process is shown to be capable of centimeter‐scale parallel 3D patterning with sub‐20 nm resolution. It is found that PS facilitates mass transport of reactants and products, and the overall etch rate is limited by local depletion of reactants. The versatility of this direct imprinting technique is demonstrated by its ability to produce curvilinear and planar 3D features (e.g., paraboloids, parabolic cylinders, sinusoidal waves, and straight sidewall channels). Miniaturized optical elements such as diffraction gratings and microconcentrators are built and characterized highlighting potential use of PS in silicon photonics.     

New medical materials with an integral lasting effect based on fibre-forming polymers

Textile materials for medical use with immobilized biologically active substances of different classes have been developed. Modified cellulose with drugs incorporated in the macromolecule: enzymes, enzyme complexes, antioxidants, hormones, vitamins, antimicrobial components, was used as substrate. Wound coverings containing drugs of different classes and having a broad spectrum of therapeutic activity were obtained by co-immobilization. __________ Translated from Khimicheskie Volokna, No. 4, pp. 7–9, July–August, 2007.     

Reduction of ontogenetic retention decrements in rats by pretraining stressful experiences.

Five experiments with 130 Holtzman rats demonstrated that pretraining stressful experiences, either similar to or qualitatively different from the conditioning UCS, reduced ontogenetic retention decrements without directly influencing response acquisition. Ss that received pretreatment with footshock, hypothermia, or restraint on Days 16, 17, and 18 of age showed substantially improved long-term retention of conditioned fear learned at 20 days of age. It was also found that preshock enhanced retention of both an appetitive approach response and punishment of the approach response. These experiments involving extinction and undertraining manipulations indicate that the facilitation of retention was not directly attributable to acquisition strength. (50 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

TECTONIC EVOLUTION OF THE NORTHERN MARGIN OF THE CENOZOIC ARARAT BASIN,LESSER CAUCASUS,ARMENIA

This paper investigates the structure of the northern margin of the Ararat depression in a study area in SE Armenia. The depression is a Cenozoic intermontane basin located to the south of the Lesser Caucasus. The purpose is to improve understanding of the basin's structure and origin within a regional tectonic framework which has been dominated since the Late Cretaceous by the closure of Neotethys and the Arabia‐Eurasia collision. We suggest that the depression is not a graben controlled by normal faults; rather, based on detailed observations, structures in the study area are interpreted as oblique‐slip reverse and thrust faults activated in post Oligocene‐Miocene times. These compressional faults resulted in the formation of asymmetric fold structures including the Lanjanist and Urts anticlines which are well expressed in the surface relief to the north of the Ararat depression. In general the structural pattern is complicated by secondary normal faults which resulted in superimposed gravitational slope processes and erosion. Major structures in the study area originated in a compressional setting associated with the closure of Neotethys since the latest Cretaceous. Post‐collisional strike‐slip faulting was linked to convergence of the Arabian and Eurasian plate margins. Pliocene and Quaternary structures, some still active, show evidence of structural inheritance. The Armenian portion of the Ararat depression contains obduction‐related nappes, anticlines and thrust faults which have potential as structural traps for hydrocarbons. These should be investigated in detail using advanced geophysical methods including 2D and 3D seismic analyses.