Recently, megastable systems have grabbed many researchers’ interests in the area of nonlinear dynamics and chaotic systems. In this paper, the oscillatory terms’ coefficients of the simplest megastable oscillator are forced to blink in time. The forced system can generate an infinitive number of hidden attractors without changing parameters. The behavior of these hidden attractors can be chaotic, tori, and limit cycle. The attractors’ topology of the system seems unique and looks like picture frames. Besides, the existence of different coexisting (...) attractors with different kinds of behaviors reflects the system's high sensitivity. Using the sample entropy algorithm, the system’s complexity for different initial values is assessed. In addition, the circuit of the introduced forced system is designed, and the possibility of implicating the system with analog elements is investigated. (shrink)

Here, a novel conservative chaotic oscillator is presented. Various dynamics of the oscillator are examined. Studying the dynamical properties of the oscillator reveals its unique behaviors. The oscillator is multistable with symmetric dynamics. Equilibrium points of the oscillator are investigated. Bifurcations, Lyapunov exponents, and the Poincare section of the oscillator’s dynamics are analyzed. Also, the oscillator is investigated from the viewpoint of initial conditions. The study results show that the oscillator is conservative and has no dissipation. It also has various (...) dynamics, such as equilibrium point and chaos. The stability analysis of equilibrium points shows there are both stable and unstable fixed points. (shrink)

The Value of Trees project, funded bythe International Development Research Council ofCanada (IDRC), supported the joint efforts of theUniversity of Alberta and the University of Zimbabweto investigate the economic costs and benefitsassociated with trees and forests in the small holderfarming sector in Zimbabwe. The Value of Trees project provided funding for graduate students andfaculty from the two participating universities tocarry out studies in the disciplines of forestry,agricultural economics, and sociology in order toprovide policy recommendations regarding the role ofwoodlands in sustainable (...) small holder farming in acontext where agricultural production appears to putincreasing stress on woodlands. The numerous projectsincluded such topics as the following: the use offuelwood under conditions of scarcity, tree tenure andlocal institutions in woodland use and sustainability,gender and wealth as related to tree planting andconservation, time preferences in natural resourceconsumption, ownership and economic impact ofeucalyptus woodlots, cultural and economic valuesassociated with woodlands, and uses and conflictsrelating to woodlands across different land categoriessuch as resettlement land and state forests. Manyother studies were not funded by, but were associatedwith Value of Trees. The findings fall withintwo broad categories. The first set includes thosedirectly related to generating values for differentaspects of the woodlands, particularly from theperspectives of rural households. The main finding isthat despite being highly valued by local people forboth economic and social reasons, woodlands are rankedlower in importance by local farmers than agriculturalland. The second set of findings relates to thecomplexities of the social system of the woodlands.Local institutions, history, resource conflicts, andtenure issues emerge as key to understanding the waythat people interact with the woodlands. Finally,local people have valuable knowledge and strategies tooffer in the design of sustainable management. Thepolicy implications of these findings for Zimbabwe arethat economic incentives could be important in asustainable woodlands strategy, but that anysuccessful program must incorporate an understandingof the profoundly complex and at times contradictoryhuman dynamics of woodland use and values. (shrink)