Hysteresis and Post Walrasian Economics

Macroeconomics, hysteresis The “new consensus” dsge (dynamic stochastic general equilibrium) macroeconomic model has microfoundations provided by a single representative agent. In this model shocks to the economic environment do not have any lasting effects. In reality adjustments at the micro level are made by heterogeneous agents, and the aggregation problem cannot be assumed away. In this paper we show that the discontinuous adjustments made by heterogeneous agents at the micro level mean that shocks have lasting effects, aggregate variables containing a selective, erasable memory of the shocks experienced. This hysteresis framework provides foundations for the post-Walrasian analysis of macroeconomic systems

OPPORTUNITY COSTS, SHARE LEASING, AND PREVENTED PLANTING CLAIMS IN CROP INSURANCE

This paper determines whether the opportunity costs of share leasing and the share amounts of farmers/tenants affect the likelihood of submitting a prevented planting claim. Results from our probit analysis shows that lower opportunity costs of share leasing and higher farmer/tenant share amount can increase the probability of submitting a prevented planting. These results have potential implications for setting prevented planting buy-up rates and crop insurance compliance procedures.Risk and Uncertainty,

Three-dimensional cell to tissue assembly process

The present invention relates a 3-dimensional cell to tissue and maintenance process, more particularly to methods of culturing cells in a culture environment, either in space or in a gravity field, with minimum fluid shear stress, freedom for 3-dimensional spatial orientation of the suspended particles and localization of particles with differing or similar sedimentation properties in a similar spatial region

A Nanoscale Parametric Feedback Oscillator

We describe and demonstrate a new oscillator topology, the parametric feedback oscillator (PFO). The PFO paradigm is applicable to a wide variety of nanoscale devices and opens the possibility of new classes of oscillators employing innovative frequency-determining elements, such as nanoelectromechanical systems (NEMS), facilitating integration with circuitry and system-size reduction. We show that the PFO topology can also improve nanoscale oscillator performance by circumventing detrimental effects that are otherwise imposed by the strong device nonlinearity in this size regime

13.4.12. Control of Phragmites or Common Reed

Phragmites, or common reed, is a perennial grass often associated with wetlands. When phragmites is interspersed with open water or with other vegetation, waterbirds and small mammals find cover among the stems. Its dense root systems strengthen dikes and roads. On many sites, however, this robust emergent forms monotypic, impenetrable stands having little value for waterfowl. Ducks occasionally nest on the edges of large stands, but avoid the dense interior. Phragmites is native to North America and is found worldwide, primarily in lowland temperate regions. Phragmites can occupy upland sites with seeps, or grow in brackish or fresh water several feet deep. Large monocultures are usually associated with impounded areas and resultant stabilized water regimes. Such sites, having levees or water-control structures that keep large areas moist for long periods, create ideal situations for phragmites to become a problem. The plants are less competitive when there is variation in water levels among wet and dry seasons and years. Growth is often stunted where soil fertility is extremely high or low or where salinity is high. Phragmites usually establishes itself on dry borders of marshes, but frequently invades shallow water foraging sites by out-competing and subsequently replacing more desirable emergent plants. Because waterfowl benefit from interspersion of phragmites with other plant species and water, we do not recommend eradication of this plant from wetlands. Instead, phragmites should be controlled only to the degree necessary to achieve management objectives. By understanding the ecology and life history of phragmites, such control is more easily achieved

13.4.12. Control of Phragmites or Common Reed

Phragmites, or common reed, is a perennial grass often associated with wetlands. When phragmites is interspersed with open water or with other vegetation, waterbirds and small mammals find cover among the stems. Its dense root systems strengthen dikes and roads. On many sites, however, this robust emergent forms monotypic, impenetrable stands having little value for waterfowl. Ducks occasionally nest on the edges of large stands, but avoid the dense interior. Phragmites is native to North America and is found worldwide, primarily in lowland temperate regions. Phragmites can occupy upland sites with seeps, or grow in brackish or fresh water several feet deep. Large monocultures are usually associated with impounded areas and resultant stabilized water regimes. Such sites, having levees or water-control structures that keep large areas moist for long periods, create ideal situations for phragmites to become a problem. The plants are less competitive when there is variation in water levels among wet and dry seasons and years. Growth is often stunted where soil fertility is extremely high or low or where salinity is high. Phragmites usually establishes itself on dry borders of marshes, but frequently invades shallow water foraging sites by out-competing and subsequently replacing more desirable emergent plants. Because waterfowl benefit from interspersion of phragmites with other plant species and water, we do not recommend eradication of this plant from wetlands. Instead, phragmites should be controlled only to the degree necessary to achieve management objectives. By understanding the ecology and life history of phragmites, such control is more easily achieved

A comparison of ground-based and space flight data: Atomic oxygen reactions with boron nitride and silicon nitride

The effects of atomic oxygen on boron nitride (BN) and silicon nitride (Si3N4) have been studied in low Earth orbit (LEO) flight experiments and in a ground-based simulation facility at Los Alamos National Laboratory. Both the in-flight and ground-based experiments employed the materials coated over thin (approx 250 Angstrom) silver films whose electrical resistance was measured in situ to detect penetration of atomic oxygen through the BN and Si3N4 materials. In the presence of atomic oxygen, silver oxidizes to form silver oxide, which has a much higher electrical resistance than pure silver. Permeation of atomic oxygen through BN, as indicated by an increase in the electrical resistance of the silver underneath, was observed in both the in-flight and ground-based experiments. In contrast, no permeation of atomic oxygen through Si3N4 was observed in either the in-flight or ground-based experiments. The ground-based results show good qualitative correlation with the LEO flight results, thus validating the simulation fidelity of the ground-based facility in terms of reproducing LEO flight results

A Passive Phase Noise Cancellation Element

We introduce a new method for reducing phase noise in oscillators, thereby improving their frequency precision. The noise reduction device consists of a pair of coupled nonlinear resonating elements that are driven parametrically by the output of a conventional oscillator at a frequency close to the sum of the linear mode frequencies. Above the threshold for parametric response, the coupled resonators exhibit self-oscillation at an inherent frequency. We find operating points of the device for which this periodic signal is immune to frequency noise in the driving oscillator, providing a way to clean its phase noise. We present results for the effect of thermal noise to advance a broader understanding of the overall noise sensitivity and the fundamental operating limits

High intensity 5 eV O-atom exposure facility for material degradation studies

An atomic oxygen exposure facility was developed for studies of material degradation. The goal of these studies is to provide design criteria and information for the manufacture of long life (20 to 30 years) construction materials for use in low Earth orbit. The studies that are being undertaken will provide: (1) absolute reaction cross sections for the engineering design problems, (2) formulations of reaction mechanisms for use in the selection of suitable existing materials and the design of new more resistant ones, and (3) the calibration of flight hardware (mass spectrometers, etc.) in order to directly relate experiments performed in low Earth orbit to ground based investigations. The facility consists of a CW laser sustained discharge source of O-atoms, an atomic beam formation and diagnostics system, a spinning rotor viscometer, and provision for using the system for calibration of actual flight instruments

Signal Amplification by Sensitive Control of Bifurcation Topology

We describe a novel amplification scheme based on inducing dynamical changes to the topology of a bifurcation diagram of a simple nonlinear dynamical system. We have implemented a first bifurcation-topology amplifier using a coupled pair of parametrically driven high-frequency nanoelectromechanical systems resonators, demonstrating robust small-signal amplification. The principles that underlie bifurcation-topology amplification are simple and generic, suggesting its applicability to a wide variety of physical, chemical, and biological systems