Cold air outbreaks and their signature in the ozonometric data at the mountain station near Kislovodsk, Russia

International audienceTwo cases of cold air outbreak in November 2001 are analyzed on the basis of ozone concentration measurements and weather data at the mountain station (43°44' N, 42°43 E, 2070 m a.s.l.) near Kislovodsk, North Caucasus, Russia. Two cold fronts, with fast clearing up in the rear of the cloud zone, passed the station in the morning of 12 and 16 November. In both cases, the ozone concentration drops down to 7?8 ppb within the frontal cloud zones, under 100% relative humidity, RH, and then sharply increases to 43?45 ppb in dry (RH about 50%), cold air during several hours. After a warm front passage (12 November) or RH growth in the cold post-frontal airmass (16 November), the ozone concentration decreases again to its average values near 30 ppb. Neither diurnal cycle nor photochemical generation could produce in the ozonometric data this specific "drop-and-peak'' signature which is considered to be caused by cold outbreak with post-frontal flow of "dry air stream'' type. Synoptic situation and tropopause topography are analyzed using the objective analysis data and METEOSAT images in the water vapor radiation band. It is concluded that the ozone growth in the rear of the cold fronts is associated with sinking of substratospheric or stratospherically influenced air from the areas of tropopause folding. Motion of cold surges with their frontal zones, jet streams, and tropopause folds is analyzed, including development of wave disturbances at the streamers and formation of substratospheric air "tongues'' underflowing the high tropopause and representing "aged'' intrusions

A short survey on nonlinear models of the classic Costas loop: rigorous derivation and limitations of the classic analysis

Rigorous nonlinear analysis of the physical model of Costas loop --- a classic phase-locked loop (PLL) based circuit for carrier recovery, is a challenging task. Thus for its analysis, simplified mathematical models and numerical simulation are widely used. In this work a short survey on nonlinear models of the BPSK Costas loop, used for pre-design and post-design analysis, is presented. Their rigorous derivation and limitations of classic analysis are discussed. It is shown that the use of simplified mathematical models, and the application of non rigorous methods of analysis (e.g., simulation and linearization) may lead to wrong conclusions concerning the performance of the Costas loop physical model.Comment: Accepted to American Control Conference (ACC) 2015 (Chicago, USA

Limitations of the classical phase-locked loop analysis

Nonlinear analysis of the classical phase-locked loop (PLL) is a challenging task. In classical engineering literature simplified mathematical models and simulation are widely used for its study. In this work the limitations of classical engineering phase-locked loop analysis are demonstrated, e.g., hidden oscillations, which can not be found by simulation, are discussed. It is shown that the use of simplified dynamical models and the application of simulation may lead to wrong conclusions concerning the operability of PLL-based circuits

New aspects of the Z2_{\textrm 2} ×\times Z2_{\textrm 2}-graded 1D superspace: induced strings and 2D relativistic models

A novel feature of the ${\mathbb Z}_2\times {\mathbb Z}_2$-graded supersymmetry which finds no counterpart in ordinary supersymmetry is the presence of $11$-graded exotic bosons (implied by the existence of two classes of parafermions). Their interpretation, both physical and mathematical, presents a challenge. The role of the "exotic bosonic coordinate" was not considered by previous works on the one-dimensional ${\mathbb Z}_2\times {\mathbb Z}_2$-graded superspace (which was restricted to produce point-particle models). By treating this coordinate at par with the other graded superspace coordinates new consequences are obtained. The graded superspace calculus of the ${\mathbb Z}_2\times {\mathbb Z}_2$-graded worldline super-Poincar\'e algebra induces two-dimensional ${\mathbb Z}_2\times {\mathbb Z}_2$-graded relativistic models; they are invariant under a new ${\mathbb Z}_2\times {\mathbb Z}_2$-graded $2D$ super-Poincar\'e algebra which differs from the previous two ${\mathbb Z}_2\times {\mathbb Z}_2$-graded $2D$ versions of super-Poincar\'e introduced in the literature. In this new superalgebra the second translation generator and the Lorentz boost are $11$-graded. Furthermore, if the exotic coordinate is compactified on a circle ${\bf S}^1$, a ${\mathbb Z}_2\times {\mathbb Z}_2$-graded closed string with periodic boundary conditions is derived. The analysis of the irreducibility conditions of the $2D$ supermultiplet implies that a larger $(\beta$-deformed, where $\beta\geq 0$ is a real parameter) class of point-particle models than the ones discussed so far in the literature (recovered at $\beta=0$) is obtained. While the spectrum of the $\beta=0$ point-particle models is degenerate (due to its relation with an ${\cal N}=2$ supersymmetry), this is no longer the case for the $\beta> 0$ models.Comment: 28 page

Constructions of regular algebras Lpw(G)L_p^w(G)

Criterion of (Shilov) regularity for weighted algebras $L_1^w(G)$ on a locally compact abelian group $G$ is known by works of Beurling (1949) and Domar (1956). In the present paper this criterion is extended to translation invariant weighted algebras $L_p^w(G)$ with $p>1$. Regular algebras $L_p^w(G)$ are constructed on any sigma-compact abelian group $G$. It was proved earlier by the author that sigma-compactness is necessary (in the abelian case) for the existence of weighted algebras $L_p^w(G)$ with $p>1$.Comment: Submitted to Mat. Sborni

Formation of human capital as a key factor in ensuring the national security of agriculture in the digital economy

Over the past few years in many literary sources and the media an issue of the digital economy is rapidly gaining popularity due to the qualitative technological changes in society. In current circumstances the qualitative component of labor resources called “human capital” is a priority value. The authors have identified the main realities of the development of agribusiness, studied the main directions of information support on the example of the agricultural sector of the economy and identified the root causes of the slowdown in the innovation development of agriculture in Russia, the features of using information technologies in agribusiness have been considered in detail.peer-reviewe