The Efficiency of Voluntary Incentive Policies for Preventing Biodiversity Loss

In this paper we analyze the efficiency of voluntary incentive-based land-use policies for biodiversity conservation. Two factors combine to make it difficult to achieve an efficient result. First, the spatial pattern of habitat across multiple landowners is important for determining biodiversity conservation results. Second, the willingness of private landowners to accept a payment in exchange for enrolling in a conservation program is private information. Therefore, a conservation agency cannot easily control the spatial pattern of voluntary enrollment in conservation programs. We begin by showing how the distribution of a landowner's willingness-to-accept a conservation payment can be derived from a parcel-scale land-use change model. Next we combine the econometric land-use model with spatial data and ecological models to simulate the effects of various conservation program designs on biodiversity conservation outcomes. We compare these results to an estimate of the efficiency frontier that maximizes biodiversity conservation at each level of cost. The frontier mimics the regulator's solution to the biodiversity conservation problem when she has perfect information on landowner willingness-to-accept. Results indicate that there are substantial differences in biodiversity conservation scores generated by the incentive-based policies and efficient solutions. The performance of incentive-based policies is particularly poor at low levels of the conservation budget where spatial fragmentation of conserved parcels is a large concern. Performance can be improved by encouraging agglomeration of conserved habitat and by incorporating basic biological information, such as that on rare habitats, into the selection criteria.

Exoskeleton master controller with force-reflecting telepresence

A thorough understanding of the requirements for successful master-slave robotic systems is becoming increasingly desirable. Such systems can aid in the accomplishment of tasks that are hazardous or inaccessible to humans. Although a history of use has proven master-slave systems to be viable, system requirements and the impact of specifications on the human factors side of system performance are not well known. In support of the next phase of teleoperation research being conducted at the Armstrong Research Laboratory, a force-reflecting, seven degree of freedom exoskeleton for master-slave teleoperation has been concepted, and is presently being developed. The exoskeleton has a unique kinematic structure that complements the structure of the human arm. It provides a natural means for teleoperating a dexterous, possibly redundant manipulator. It allows ease of use without operator fatigue and faithfully follows human arm and wrist motions. Reflected forces and moments are remotely transmitted to the operator hand grip using a cable transmission scheme. This paper presents the exoskeleton concept and development results to date. Conceptual design, hardware, algorithms, computer architecture, and software are covered

Price Level Convergence Among United States Cities: Lessons for the European Central Bank

We study the dynamics of price indices for major U.S. cities using panel econometric methods and find that relative price levels among cities mean revert at an exceptionally slow rate. In a panel of 19 cities from 1918 to 1995, we estimate the half-life of convergence to be approximately nine years. These estimates provide an upper bound on speed of convergence that participants in European Monetary Union are likely to experience. The surprisingly slow rate of convergence can be explained by a combination of the presence of transportation costs, differential speeds of adjustment to small and large shocks, and the inclusion of non-traded good prices in the overall price index.

Undulation instability in a bilayer lipid membrane due to electric field interaction with lipid dipoles

Bilayer lipid membranes [BLMs] are an essential component of all biological systems, forming a functional barrier for cells and organelles from the surrounding environment. The lipid molecules that form membranes contain both permanent and induced dipoles, and an electric field can induce the formation of pores when the transverse field is sufficiently strong (electroporation). Here, a phenomenological free energy is constructed to model the response of a BLM to a transverse static electric field. The model contains a continuum description of the membrane dipoles and a coupling between the headgroup dipoles and the membrane tilt. The membrane is found to become unstable through buckling modes, which are weakly coupled to thickness fluctuations in the membrane. The thickness fluctuations, along with the increase in interfacial area produced by membrane buckling, increase the probability of localized membrane breakdown, which may lead to pore formation. The instability is found to depend strongly on the strength of the coupling between the dipolar headgroups and the membrane tilt as well as the degree of dipolar ordering in the membrane.Comment: 29 pages 8 fig

Small Grain Forage Yields at Overton 1986-1989

Last updated: 6/9/200

Rye Forage Yields at Overton for 1998-99 and Three-Year Means

Last updated: 6/15/201

Small grain forage yields at Overton for 1997-1998 and three-year means

Last updated: 10/19/201

Herbicidal Control of Annual Ryegrass in Wheat

Last updated: 6/9/200