The survey gives an overview of the achievements in topology of real algebraic varieties in the direction initiated in the early 70th by V. I. Arnold and V. A. Rokhlin. We make an attempt to systematize the principal results in the subject. After an exposition of general tools and results, special attention is paid to surfaces and curves on surfaces.

Aperiodic optical variability is a common property of Active Galactic Nuclei (AGNs), though its physical origin is still open to question. To study the origin of the optical – ultraviolet variability in AGN, we compare light curves of two models to observations of quasar 0957+561 in terms of a structure function analysis. In the starburst (SB) model, random superposition of supernovae in the nu...

Wind turbine power curves are calibrated by turbine manufacturers under requirements stipulated by the International Electrotechnical Commission to provide a functional mapping between the mean wind speed v and the mean turbine power output P. Wind plant operators employ these power curves to estimate or forecast wind power generation under given wind conditions. However, it is general knowledg...

In this chapter we begin a study of special curves lying on surfaces in R. An asymptotic curve on a surface M ⊂ R is a curve whose velocity always points in a direction in which the normal curvature of M vanishes. In some sense, M bends less along an asymptotic curve than it does along a general curve. As a simple example, the straight lines on the cylinder (u, v) 7→ (cosu, sinu, v) formed by s...

an ion chromatography (ic) method for simultaneous determination of benzoic, salicylic and sorbic acids was developed. in this method the samples were purified by solid-phase extraction. the analytes were then eluted with methanol from c18 cartridge. the separation was performed on ion-exclusion column by an isocratic elution with 0.25 mmol /l sulfuric acid solution containing 20% (v/v) acetone...

OBJECTIVE Respiratory pressure-volume curves fitted to exponential equations have been used to assess disease severity and prognosis in spontaneously breathing patients with idiopathic pulmonary fibrosis. Sigmoidal equations have been used to fit pressure-volume curves for mechanically ventilated patients but not for idiopathic pulmonary fibrosis patients. We compared a sigmoidal model and an e...

Quantum transport properties of pure and functioned infinite lead-connection region-lead systembased on the zigzag graphene nanoribbon (2-zGNR) have been investigated. In this work the effectof the doping functionalization on the quantum transport of the 2-zGNR has been computationallystudied. Also, the effect of the imposed gate voltages (-3.0, 0.0 and +3.0 V) and bias voltages 0.0 to2.0 V hav...

AIMS Three-dimensional (3D)-echocardiography speckle imaging allows the evaluation of frame-by-frame strain and volume changes simultaneously. The aim of the present investigation was to describe the strain-volume combined assessment in different patterns of cardiac remodelling. METHODS AND RESULTS Fifty patients received a 3D acquisition. Patients were classified as follows: healthy subjects...

an ion chromatography (ic) method for simultaneous determination of benzoic, salicylic and sorbic acids was developed. in this method the samples were purified by solid-phase extraction. the analytes were then eluted with methanol from c18 cartridge. the separation was performed on ion-exclusion column by an isocratic elution with 0.25 mmol /l sulfuric acid solution containing 20% (v/v) acetone...