Agro-Ecological Assessment for the Transition of the Agricultural Sector in Ukraine. Part I: Socio-Economic Aspects

Since 1991, Ukraine has been undergoing a transformation of its economic and social system to enable the transition to a market economy. There are a number of positive developments that have already resulted from the changes in the socio-economic environment. However the transformation of farming systems into new forms did not greatly improve the sustainable use of natural resources or strengthen the economic performance, so that the influence of this intervention on sustainability of farming systems in Ukraine has had more negative than positive results. Large-scale farms continue to over-exploit natural resources and new private farmers, lacking in experience, knowledge and financial resources, continue to use obsolete technologies that are economically inefficient and may cause land degradation. All the components of the farming sector such as agricultural enterprises, household plots, and individual private farms, still remain problematic in terms of efficiency and are constrained by policies and inadequate markets. While economic conditions for agriculture have changed considerably since the beginning of the 1990s, agricultural policy in Ukraine was focused on trying to revive the production level, without the comprehensive analysis of agro-ecological conditions, internal and external markets, infrastructure, farmers' incentives etc. Rational agricultural land use is imperative in Ukraine. Existing agricultural systems are not appropriate for changing production, technological, economic or ecological realities. There is an urgent need for major policy changes in Ukraine towards rural welfare growth, sustainable agriculture and efficient land management, and establishment of agricultural market networks supported by adequate legislation. With the additional pressure of transition to a market economy, a new agricultural paradigm is required. This paper is the first in a series of reports on "Agro-ecological Assessment for Transition of the Agricultural Sector in Ukraine". The reports aim at further elaboration of integrated strategies and policies towards maintaining the sustainability of natural resources and the environment while remaining economically viable and internationally competitive. This paper on "Socio-economic analysis" describes the main socio-economic features of the transition processes in the Ukrainian agricultural sector, trends in agricultural production, and changes in its farming systems and land use. The second report "Land Resources and Agricultural Productivity: Methodology and Results" provides the inventory of natural (land, climatic) resources and the evaluation of biophysical limitations and potentials of the crop production in Ukraine at the national and regional levels. The third paper "Climate Change Impacts on Agricultural Productivity: Methodology and Results" investigates impacts of climate change/variability on the crop production and land use change in Ukraine on national and regional scales and indicates possible ways of adaptation over the coming three decades

Diagrammatic Quantum Monte Carlo for Two-Body Problem: Exciton

We present a novel method for precise numerical solution of the irreducible two-body problem and apply it to excitons in solids. The approach is based on the Monte Carlo simulation of the two-body Green function specified by Feynman's diagrammatic expansion. Our method does not rely on the specific form of the electron and hole dispersion laws and is valid for any attractive electron-hole potential. We establish limits of validity of the Wannier (large radius) and Frenkel (small radius) approximations, present accurate data for the intermediate radius excitons, and give evidence for the charge transfer nature of the monopolar exciton in mixed valence materials.Comment: 4 pages, 5 figure

Agro-ecological Assessment for the Transition of the Agricultural Sector in Ukraine: Methodology and Results for Baseline Climate

Since 1991, Ukraine has been undergoing a transformation of its economic and social system to enable the transition to a market economy. There are a number of developments that have already resulted from the changes in the socio-economic environment. However the transformation of farming systems into new forms has not so far greatly improved the sustainable use of natural resources or strengthened the economic performance, so that the influence of this intervention on sustainability of farming systems in Ukraine has had more negative than positive results. Large-scale farms continue to over-exploit natural resources and new private farmers, lacking in experience, knowledge and financial resources, continue to use obsolete technologies that are economically inefficient, do not enhance productivity and may cause land degradation. All the components of the farming sector such as agricultural enterprises, household plots, and individual private farms, still remain problematic in terms of efficiency and are constrained by policies and inadequate markets. While economic conditions for agriculture have changed considerably since the beginning of the 1990s, agricultural policy in Ukraine was focused on trying to revive the production level, without the comprehensive analysis of agro-ecological conditions, internal and external markets, infrastructure, farmers' incentives etc. Rational agricultural land use is imperative in Ukraine. Existing agricultural systems are not appropriate for changing production, technological, economic or ecological realities. There is an urgent need for major policy changes in Ukraine towards rural welfare growth, sustainable agriculture and efficient land management, and establishment of agricultural market networks supported by adequate legislation. With the additional pressure of transition to a market economy, a new agricultural paradigm is required. This paper is the second in a series of three reports on Agro-ecological Assessment for the Transition of the Agricultural Sector in Ukraine. The reports aim at further elaboration of integrated strategies and policies towards maintaining the sustainability of natural resources and the environment while remaining economically viable and internationally competitive. The first report on Socio-economic analysis describes the main socio-economic features of the transition processes in the Ukrainian agricultural sector, trends in agricultural production, and changes in its farming systems and land use. This report "Land Resources and Agricultural Productivity: Methodology and Results for Base Line Climate" provides the inventory of natural (land, climatic) resources and the evaluation of biophysical limitations and potentials of the crop production in Ukraine at the national, regional and subregional levels. The third report "Climate Change Impacts on Agricultural Productivity: Methodology and Results" investigates impacts of climate change/variability on the crop production and land use change in Ukraine on national and regional scales and indicates possible ways of adaptation over the coming three decades

Techniques for the Synthesis of Reversible Toffoli Networks

This paper presents novel techniques for the synthesis of reversible networks of Toffoli gates, as well as improvements to previous methods. Gate count and technology oriented cost metrics are used. Our synthesis techniques are independent of the cost metrics. Two new iterative synthesis procedure employing Reed-Muller spectra are introduced and shown to complement earlier synthesis approaches. The template simplification suggested in earlier work is enhanced through introduction of a faster and more efficient template application algorithm, updated (shorter) classification of the templates, and presentation of the new templates of sizes 7 and 9. A novel ``resynthesis'' approach is introduced wherein a sequence of gates is chosen from a network, and the reversible specification it realizes is resynthesized as an independent problem in hopes of reducing the network cost. Empirical results are presented to show that the methods are effective both in terms of the realization of all 3x3 reversible functions and larger reversible benchmark specifications.Comment: 20 pages, 5 figure

Interplay between charge-lattice interaction and strong electron correlations in cuprates: phonon anomaly and spectral kinks

We investigate the interplay between strong electron correlations and charge-lattice interaction in cuprates. The coupling between half breathing bond stretching phonons and doped holes in the t-t'-J model is studied by limited phonon basis exact diagonalization method. Nonadiabatic electron-phonon interaction leads to the splitting of the phonon spectral function at half-way to the zone boundary at $\vec{q}_s=\{(\pm \pi / 2, 0), (0, \pm \pi / 2) \}$ and to low energy kink feature in the electron dispersion, in agreement with experimental observations. Another kink due to strong electron correlation effects is observed at higher energy, depending on the strength of the charge-lattice coupling.Comment: 4 pages, 3 figure