Exploration and revaluation of old autochthonous varieties in the Republic of Moldova

In the Republic of Moldova during the last 40‑50 years the quota of old autochthonous varieties in industrial vineyards permanently decreased and nowadays the majority of these varieties are present only in the Institute's Collection. During this time only an insignificant part of these resources were included in the research projects and, thus, their potential value for viticulture requires insights. The aim of the present work was the preliminary diversity evaluation of these varieties. Thirty-six cultivars were described according to the primary and secondary ampelographic descriptors, and to the phenotyping protocols for eno-carpological characterization. Based on the obtained data and on literature, some characteristics were established such as classification into Negrul's eco-geographical proles, berry colour, agro-biological properties and resistance to abiotic factors and pathogens

Boundary value problems of elasticity theory for plane domains with one-dimensional elastic reinforcements

This article is a translation of an article published in Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No 1, pp 103-114 Jan-Feb 1991.Many authors have examined problems related to the load transmission from an elastic rod to an elastic plane. It was assumed in the majority of investigationa that the stringer is a thin rectilinear rod transmitting only longitudinal forces while the rod contact with the plane is realized along a line. different modifications of sheet contact with a rectilinear tensile stringer considered as an inner stringer of finite length or as an infinite edge stringer were analyzed in [1, 2]. Problems about the reinforcement of holes in a plate by a thin rod of constant section that possesses bending and longitudinal stiffnesses were solved in [3]. The eccentricity of the connection between the shell middle surface and the rod was taken into account in [4] in a study of shells reinforced by thin curvilinear rods. Other models of the one-dimensional element connected to an elastic medium without taking account of its bending stiffness were analyzed in [5, 6]. Solutions of a number of problems with circular reinforcing elements are obtained in [7]. An isotropic finite or infinite, linearly elastic plate reinforced along part or all of the boundary and along certain internal lines by elastic curvilinear rods possessing variable longitudinal and bending stiffnesses, variable curvature and thickness, the eccentricity of the connection to the plate and with an arbitrary transverse section shape symmetric relative to the plate middle surface are studied in this paper. Boundary conditions on the line of plate contact with the inner or edge elastic rods are obtained for the reinforcement models generalizing [1, 2] by using the theory of elastic rods in the case of a plane state of stress. Existence and uniqueness theorems are proved for appropriate boundary value problems; the singularity of the stresses at angles and tips of the rods are proved. The relationships obtained carry over completely to the plane strain problem for an elastic cylinder reinforced by homogeneous cylindrical shells along the generator. Some of the results described here are represented in [8]

Van der Waals forces in density functional theory: perturbational long-range electron interaction corrections

Long-range exchange and correlation effects, responsible for the failure of currently used approximate density functionals in describing van der Waals forces, are taken into account explicitly after a separation of the electron-electron interaction in the Hamiltonian into short- and long-range components. We propose a "range-separated hybrid" functional based on a local density approximation for the short-range exchange-correlation energy, combined with a long-range exact exchange energy. Long-range correlation effects are added by a second-order perturbational treatment. The resulting scheme is general and is particularly well-adapted to describe van der Waals complexes, like rare gas dimers.Comment: 8 pages, 1 figure, submitted to Phys. Rev.

Vibrational Tamm states at the edges of graphene nanoribbons

We study vibrational states localized at the edges of graphene nanoribbons. Such surface oscillations can be considered as a phonon analog of Tamm states well known in the electronic theory. We consider both armchair and zigzag graphene stripes and demonstrate that surface modes correspond to phonons localized at the edges of the graphene nanoribbon, and they can be classified as in-plane and out-of-plane modes. In addition, in armchair nanoribbons anharmonic edge modes can experience longitudinal localization in the form of self-localized nonlinear modes, or surface breather solitons.Comment: 10 pages, 10 figure

The LUC Approach to Creating a Continental-Scale Land-Cover Database for Russia

Land cover is an essential surface characteristic of the Earth. Yet -- this may come as a surprise -- there is no generally accepted, complete and universal land-cover product for Russia, as is the problem in many other parts of the world. A review of global land-cover databases concluded that one of the most pressing problems in global climate and ecosystem studies is a lack of adequate land-cover data. This may explain why land-cover mapping often leads to debate over classification schemes, use of class descriptors and labels, and product specifications. Land-use and land-cover information is required in various forms and at different scales. A variety of techniques are in current use to collect the necessary data, ranging from census studies, ground observations, to remotely sensed data. The methodological plurality has also resulted in a widely diverse number of methods to store and present these data. In view of this unsatisfactory situation, FAO and UNEP, with the support of UNESCO and a number of other organizations, have launched an initiative on harmonizing and standardizing land-use and land-cover classification systems. Another major effort has been launched by the International Geosphere-Biosphere Programme (IGBP), to serve the needs of the global environmental change research community. The IGBP-DIS Global 1 km Land-cover Project is currently underway. The project is primarily relying on NOAA AVHRR data and aims to develop and distribute a global data-set representing land-cover in terms of seventeen broad classes. Being aware of these efforts, and aiming to be consistent with and useful to the international research community, the Land-Use Change (LUC) project at IIASA decided at an early stage to be in active contact with the research groups charged with harmonizing land-use and land-cover classifications, to use their methods and standards as they would emerge. Consequently, as regards land-cover database development, the main task of the LUC project was defined as: (i) producing a complete list of land-cover categories in Europe and Northern Asia based on available national-level data sources, and (ii) which would correspond to the diversity of land-use and land-cover of this huge territory. Charged with this task, it was necessary to develop a framework allowing to concentrate the project's efforts on these problems. The objective of this paper is to present an outline and rationale of the methodology for elaborating the project's land-cover database. Comprising the major portion of the study region, the approach has been developed on the basis of Russian experience

Uniformization and an Index Theorem for Elliptic Operators Associated with Diffeomorphisms of a Manifold

We consider the index problem for a wide class of nonlocal elliptic operators on a smooth closed manifold, namely differential operators with shifts induced by the action of an isometric diffeomorphism. The key to the solution is the method of uniformization: We assign to the nonlocal problem a pseudodifferential operator with the same index, acting in sections of an infinite-dimensional vector bundle on a compact manifold. We then determine the index in terms of topological invariants of the symbol, using the Atiyah-Singer index theorem.Comment: 16 pages, no figure

Discrete breathers in polyethylene chain

The existence of discrete breathers (DBs), or intrinsic localized modes (localized periodic oscillations of transzigzag) is shown. In the localization region periodic contraction-extension of valence C-C bonds occurs which is accompanied by decrease-increase of valence angles. It is shown that the breathers present in thermalized chain and their contribution dependent on temperature has been revealed.Comment: 5 pages, 6 figure

Intriguing Heat Conduction of a Polymer Chain

We study heat conduction in a one-dimensional chain of particles with longitudinal as well as transverse motions. The particles are connected by two-dimensional harmonic springs together with bending angle interactions. Using equilibrium and nonequilibrium molecular dynamics, three types of thermal conducting behaviors are found: a logarithmic divergence with system sizes for large transverse coupling, 1/3 power-law at intermediate coupling, and 2/5 power-law at low temperatures and weak coupling. The results are consistent with a simple mode-coupling analysis of the same model. The 1/3 power-law divergence should be a generic feature for models with transverse motions.Comment: 4 page