Fluctuation-induced Distributed Resonances in Oscillatory Networks

Self-organized network dynamics prevails for systems across physics, biology and engineering. How external signals generate distributed responses in networked systems fundamentally underlies their function, yet is far from fully understood. Here we analyze the dynamic response patterns of oscillatory networks to fluctuating input signals. We disentangle the impact of the signal distribution across the network, the signals' frequency contents and the network topology. We analytically derive qualitatively different dynamic response patterns and find three frequency regimes: homogeneous responses at low frequencies, topology-dependent resonances at intermediate frequencies, and localized responses at high frequencies. The theory faithfully predicts the network-wide collective responses to regular and irregular, localized and distributed simulated signals, as well as to real input signals to power grids recorded from renewable-energy supplies. These results not only provide general insights into the formation of dynamic response patterns in networked systems but also suggest regime- and topology-specific design principles underlying network function.Comment: 7 pages, 4 figure

The AUGER experiment - status and results

The Auger experiment was designed to study the high-energy cosmic rays by measuring the properties of the showers produced in the atmosphere. The Southern Auger Observatory has taken data since January 2004. Results on mass composition, energy spectrum and anisotropy of the arrival directions are presented. The most important result is the recent observation of correlations with nearby extragalactic objects.Comment: Conferenc

The use of bio-telemetry for studying squirrel population dynamics and behavior

A full understanding of the ecology and behavior of any animal requires a knowledge of the animal\u27s movements. Historically, data from natural events involving any animal under natural conditions have been obtained from such methods as trapping, marking, recapture and visual observations. In the 1950\u27s and early 1960\u27s however, major breakthroughs in data gathering techniques were made when biologists began developing telemetering devices with which to monitor animal movement and to a limited degree, physiological parameters. Wild animals were being tracked for days, weeks and even months, continuously telemetering such events as temperature, daily and seasonal movement patterns, dispersal and behavior. Radio-telemetry, may be defined as the use of a miniature radio transmitter attached to a free roaming, wild animal, without use of restraining harnesses or wires, and capable of emitting a signal at a given frequency, which when received by a remote receiving station provides continuous data of a specific nature

Wetlands in environmental education

Wetlands are one of the most useful resources the environmentally oriented educator has at his disposal. They are his best teaching facility. Most wetlands allow active use. They provide rapid and easy direct contact study of their components. Because one can get an overall perspective, it is often easier to observe the animal populations and to sample the plant communities. Whether the wetland is a wet cattail marsh, sedge meadow, woodland swamp or acid bog the student can see it, feel it and appreciate it as a reservoir for living things. The wetland is not only easy to observe and comprehend but also provides an excellent opportunity to teach basic ecological principles and concepts, those of the ecosystem; of energy and the biogeochemical cycles; of limiting factors and of community and population organization. The wetland offers the opportunity to witness with relative simplicity the processes of orderly change we call succession. Wetlands illustrate the natural relationships of organisms to each other as well as how those organisms relate to their physical environment. Likewise, in wetlands all trophic levels from producer to carnivore are readily observed

Change in the urban-rural ecotone

Conversion of the rural Wisconsin landscape from farms to housing poses serious wildlife management and utilization problems. The problems are aggravated by the unregulated and unplanned nature of the land use changes. Purchase of farms for future development often results in removal of the entire farm from crop production. Occasionally the choicest tillable acres are rented or leased to a neighboring farmer, but even so, the remaining land is allowed to lie fallow and undergo old field succession. In a few cases pine plantations or wildlife food patches may be established or a pond constructed

A theorem on the real part of the high-energy scattering amplitude near the forward direction

We show that if for fixed negative (physical) square of the momentum transfer t, the differential cross-section ${d\sigma\over dt}$ tends to zero and if the total cross-section tends to infinity, when the energy goes to infinity, the real part of the even signature amplitude cannot have a constant sign near t = 0.Comment: 7 pages, late