A Plethora of Strange Nonchaotic Attractors

We show that it is possible to devise a large class of skew--product dynamical systems which have strange nonchaotic attractors (SNAs): the dynamics is asymptotically on fractal attractors and the largest Lyapunov exponent is nonpositive. Furthermore, we show that quasiperiodic forcing, which has been a hallmark of essentially allhitherto known examples of such dynamics is {\it not} necessary for the creation of SNAs.Comment: 16 Pages, 3 figs, two in eps format and one in gif forma

Coupling of strain and magnetism in manganite-based complex oxide heterostructures

Complex oxide thin films and heterostructures offer a wide range of properties originating from the intrinsic coupling between lattice strain and magnetic/electronic ordering. This article reviews experimental, phenomenological, and theoretical analyses of the coupling of strain with electronic and magnetic properties of mixed valence manganite heterostructures. The influence of epitaxial strain on the magnetic properties of manganite films is measured using macroscopic magnetization measurements and shown mixed reports suggesting, both, an increase and decrease in ferromagnetic phases on the application of the strain. Using polarized neutron reflectivity (PNR), a simultaneous measurement of transport and magnetic properties of manganite thin films showed direct evidence of modification in the magnetic properties on the application of bending strain. The coupling coefficient of strain and magnetism of manganite heterostructures was estimated using PNR, which not only helped to understand the correlation of elastic strain with magnetism but also explained the condition of magnetic phase order change in the phase-separated systems within a phenomenological Ginzburg Landau theory. An overview is also provided of the current perspectives and existing studies on the influence of strain on structure, electronic, magnetic, magnetic anisotropy, phase coexistence and magnetocaloric properties of mixed valence manganite heterostructures. Based on the understanding of a diverse range of perovskite functionalities, detailed perspectives on how the coupling of strain and magnetism open up pathways toward the emergence of novel device design features including the different ways of applying uniform strain, are discussed.Comment: arXiv admin note: text overlap with arXiv:1509.00912, arXiv:1009.4548 by other author

Strange Nonchaotic Attractors

Aperiodic dynamics which is nonchaotic is realized on Strange Nonchaotic attractors (SNAs). Such attractors are generic in quasiperiodically driven nonlinear systems, and like strange attractors, are geometrically fractal. The largest Lyapunov exponent is zero or negative: trajectories do not show exponential sensitivity to initial conditions. In recent years, SNAs have been seen in a number of diverse experimental situations ranging from quasiperiodically driven mechanical or electronic systems to plasma discharges. An important connection is the equivalence between a quasiperiodically driven system and the Schr\"odinger equation for a particle in a related quasiperiodic potential, giving a correspondence between the localized states of the quantum problem with SNAs in the related dynamical system. In this review we discuss the main conceptual issues in the study of SNAs, including the different bifurcations or routes for the creation of such attractors, the methods of characterization, and the nature of dynamical transitions in quasiperiodically forced systems. The variation of the Lyapunov exponent, and the qualitative and quantitative aspects of its local fluctuation properties, has emerged as an important means of studying fractal attractors, and this analysis finds useful application here. The ubiquity of such attractors, in conjunction with their several unusual properties, suggest novel applications.Comment: 34 pages, 9 figures(5 figures are in ps format and four figures are in gif format

Bifurcations and transitions in the quasiperiodically driven logistic map

We discuss several bifurcation phenomena that occur in the quasiperiodically driven logistic map. This system can have strange nonchaotic attractors (SNAs) in addition to chaotic and regular attractors; on SNAs the dynamics is aperiodic, but the largest Lyapunov exponent is nonpositive. There are a number of different transitions that occur here, from periodic attractors to SNAs, from SNAs to chaotic attractors, etc. We describe some of these transitions by examining the behavior of the largest Lyapunov exponent, distributions of finite time Lyapunov exponents and the invariant densities in the phase space.Comment: 17 Pages, 8 Figures(four figures are in ps format and four figures are in gif forma

PART-TIME FARMING: PRODUCTIVITY AND SOME IMPLICATIONS OF OFF-FARM WORK BY FARMERS

Labor and Human Capital,

Genetic Improvement and Conservation of Range and Forage Species of Arid Region of Rajasthan State of India: Achievements and Challenges

Forage crops and grasses are important in arid region of Rajasthan state of India because most of the area is rainfed. Main occupation of the farmers in the area is animal husbandry. Important green fodder crops of this region are, viz. pearl millet, cowpea, cluster bean and sorghum in Kharif season and oats, lucerne and barley (dual purpose) during Rabi season. Three perennial fodder grasses, viz. Lasiurus sindicus, Cenchrus ciliaris and Cenchrus setigerus are important in the region. Guinea grass and bajra x napier hybrid can also be cultivated where sufficient water is available throughout the year from canal irrigation or tube wells

Position and Prospects of Black Farmers in the South

Almost 94 percent of black farms in the United States have been lost since 1920, and the remaining 57,271 farms constituted only 2.3 percent of all farms in 1978. Most (95 percent) black farm operators were located in the South. However, they constituted only 5.4 percent of all farm operators in the South. Since 1959, there have been some dramatic changes not only in the number of black farms but in their composition also. Ninety three percent of the South\u27s black farmers were small, both in size and product sales, and they operated only 1.4 percent of all operated land. These black farmers were older than their white counterparts and worked fewer days off-farm. Thus most black operated farms in the South were small and they faced several unique problems along with those problems faced by other small farmers. The paper identifies, compares, and contrasts resources and characteristics of black farm operators in the 14 southern states. Relevant unpublished and published census OF agriculture data were used to provide insights into the black farmers in the South. This article provides background material for researchers and policy makers and attempts to identify those voids which may receive emphasis in future work

Incidence, Magnitude, and Determinants of Off-Farm Income in Tennessee and the South

The major objectives of this study are to identify the incidence and magnitude of of f-farm income in Tennessee and the South and to determine factors affecting off-farm income of a select group of farm families. Regression models were estimated using cross-sectional data collected from 193 randomly selected farm families in two Tennessee counties. Two models were estimated: the first, for the farm operator\u27s off-farm income; and the second, for the total off-farm income of the family. The study revealed various socioeconomic factors affecting total off-farm family income and operator\u27s off-farm income. Elasticities were also determined for each of the independent variables at their mean values to determine responsiveness of the off-farm income to changes in the independent variables