Distortions to Agricultural Incentives in Eastern Europe and Central Asia

Distorted incentives, agricultural and trade policy reforms, national agricultural development, Agricultural and Food Policy, International Relations/Trade, F13, F14, Q17, Q18,

Research on farm and livestock productivity in the central Ethiopian highlands: Initial results, 1977-1980

Describes the Ethiopian highlands assessing their potential for improved agricultural production; reports ILCA's studies on the traditional smallholder production system of the highlands; and analyzes productivity aspects of the system's crop and livestock components. Discusses the approach to farming systems research (FSR) along with the implications for adoption of the approach and its results by a national agency, some research experiences and the outlook for future research. Includes results of research on innovations consisting of improved forage/dairy cow package, improved animal traction and the cultivation of valley bottoms

Cattle herd dynamics: An integer and stochastic model for evaluating production alternatives

Presents a cattle herd simulation model which is time dynamic, stochastic, non-optimizing & integer and permits the evaluation of herd performance under alternative production regimes; discusses the analytical background to the biological relationships represented in the model, describes detailed algorithms used in the computer simulation model, and outlines necessary steps for the application of the model

The scope for improvement

Discusses the need for identifying sociological and economic possibilities for improvement in pastoral production systems, mentioning the major steps involved, particularly, identification of potential improvements, prediction of their likely impact on net production & quality of life; prediction of the probability of adoption; and assessment of the rapidity with which the improvements will bear fruit

Low-cost modifications of the traditional Ethiopian tine plough for land shaping and surface drainage of heavy clay soils: Preliminary results from on-farm verification trials

Describes modifications to the traditional ox-drawn ard plow (maresha) for use in the construction of terraces for soil conservation and of raised beds and furrows to facilitate drainage on heavy clay soils together with results of on-station and on-farm tests. Both modifications can be made by village craftsmen

Research with a farming systems perspective at ILCA

Discusses the historical context of ILCA's research, the principal types of animal production systems and the stages in ILCA's farming systems research. Describes the smallholder farming in the Ethiopian highlands & humid zone, the agropastoralists of the sub-humid zone, systems research in pastoral areas of eastern Africa (Kenya & Ethiopia), characteristics of the arid and semi-arid zones of West Africa and the role of modelling in the system. Ends with a summary of past experience

Anderson localization as a parametric instability of the linear kicked oscillator

We rigorously analyse the correspondence between the one-dimensional standard Anderson model and a related classical system, the `kicked oscillator' with noisy frequency. We show that the Anderson localization corresponds to a parametric instability of the oscillator, with the localization length determined by an increment of the exponential growth of the energy. Analytical expression for a weak disorder is obtained, which is valid both inside the energy band and at the band edge.Comment: 7 pages, Revtex, no figures, submitted to Phys. Rev.

The use of single oxen for crop cultivation in Ethiopia

Reports experiences with on-farm trials to assess the use of single oxen for work on mixed smallholder farms in the central highlands of Ethiopia, with particular reference to draft power and agricultural production, design and testing of the single ox technique, and results obtained during the 1983 crop year and future prospects with respect to feed requirements and advantages of using the single ox

One-dimensional tight-binding models with correlated diagonal and off-diagonal disorder

We study localization properties of electronic states in one-dimensional lattices with nearest-neighbour interaction. Both the site energies and the hopping amplitudes are supposed to be of arbitrary form. A few cases are considered in details. We discuss first the case in which both the diagonal potential and the fluctuating part of the hopping amplitudes are small. In this case we derive a general analytical expression for the localization length, which depends on the pair correlators of the diagonal and off-diagonal matrix elements. The second case we investigate is that of strong uncorrelated disorder, for which approximate analytical estimates are given and compared with numerical data. Finally, we study the model with short-range correlations which constitutes an extension with off-diagonal disorder of the random dimer model.Comment: 11 pages, 7 EPS figures; submitted to "Physica E

Contact symmetry of time-dependent Schr\"odinger equation for a two-particle system: symmetry classification of two-body central potentials

Symmetry classification of two-body central potentials in a two-particle Schr\"{o}dinger equation in terms of contact transformations of the equation has been investigated. Explicit calculation has shown that they are of the same four different classes as for the point transformations. Thus in this problem contact transformations are not essentially different from point transformations. We have also obtained the detailed algebraic structures of the corresponding Lie algebras and the functional bases of invariants for the transformation groups in all the four classes