The Farrell-Hsiang method revisited

We present a sufficient condition for groups to satisfy the Farrell-Jones Conjecture in algebraic K-theory and L-theory. The condition is formulated in terms of finite quotients of the group in question and is motivated by work of Farrell-Hsiang.Comment: This version is different from the published version. A number of typos and an incorrect formula for the transfer before Lemma 6.3 pointed out by Holger Reich have been correcte

Estimating Cotton Harvest Cost per Acre When Harvest Days are Stochastic

The cotton harvesting industry is in the beginnings of its next technological advance, cotton harvesters that form cotton modules inside the machine then deposit them off the rows. These new machines eliminate the need for extra labor and equipment, but are more expensive than conventional pickers. Increased field efficiency is also a benefit of the on-board module builders. The problem facing producers is determining the optimal number of acres to plan for harvest when trying to decide which harvester to purchase. This paper examines two objectives. First, determine the cost per acre of both conventional and on-board module harvester systems for different acreage levels assuming harvest hours per year are fixed. Second, make the harvest hours per season stochastic to determine the cost per acre under different farm sizes for each type of cotton picker. The results show that the maximum benefits of the new machines are realized with larger farms when a larger number of acres need to be harvested in the harvest period. Results should help farmers plan both their cotton acre estimates as well as their purchase decisions for new cotton pickers.cotton harvester, harvest hours, cost per acre, field efficiency, on-board module builder, Crop Production/Industries, Financial Economics, Risk and Uncertainty,

Calculating Cost Savings Per Acre When Harvest Days are Stochastic

New cotton harvesters have been introduced that have higher performance rate as well as eliminate extra labor and accompanying equipment. The new machines build partial modules on board the harvester. Higher field efficiency (performance rate) lets a farmers harvest his cotton in a shorter period. Precipitation causes cotton losses in both quality and quantity of the cotton. This paper seeks to measure cost per acre when harvest days are stochastic by using historic precipitation data. Cost per acre will include the cost of losses from a loss function from precipitation. Cost per acre will be adjusted for conventional versus new technology by quantifying the losses that contribute to extra costs of extended harvesting.Cotton, harvester, fieldwork days, stochastic, cost per acre, Agribusiness, Farm Management,

Surgery on SL~×En\widetilde{\Bbb{SL}}\times\Bbb{E}^n-manifolds

We show that although closed $\widetilde{\Bbb{SL}}\times\Bbb{E}^n$-manifolds do not admit metrics of nonpositive sectional curvature, the arguments of Farrell and Jones can be extended to show that such manifolds are topologically rigid, if $n\geq2$.Comment: 7 pages, AMS-LaTeX file, To appear in the Canadian Mathematical Bulletin

ECEF Position Accuracy and Reliability: Inertial Navigation with GNSS Precise Point Positioning (PPP)

This report presents experimental results for a moving platform using GPS PPP data for state estimation. Results from two PPP GPS state estimation approaches are presented: point-wise least squares (LS) and aided inertial navigation (INS). The point-wise LS results provide information about the accuracy and reliability of PPP GPS information at each measurement epoch, independent of other epochs. The INS results show the performance that can be achieved by combining information across measurement epochs. INS results are included for two different grades of IMU: navigation grade and consumer grade.The report cites publications that contain more detailed expla- nations of the GNSS error sources, computation of PPP wide area correction, and the LS and aided INS estimation algorithms

Investment Decisions and Emissions Reductions : Results from Experiments in Emissions Trading

Emissions trading is an important regulatory tool in environmental policy making. Unfortunately the effectiveness of these regulations is difficult to measure in the field due to the unavailability of appropriate data. In contrast, experiments in the laboratory can provide guidance to regulators and legislatures about the performance of different market features in emission trading programs. This paper reports on the implementation of three different institutional designs, and presents experimental results investigating important features of emissions trading regimes: the ability to make investments in emissions abatement, ability to bank allowances and a declining emissions cap, both with and without uncertainty. These features are observed in virtually all existing air pollution emissions trading programs currently in place and will almost certainly be part of future applications. Like previous experimental studies of emissions trading, this paper shows that the efficiency gains expected from economic theory emerge observationally. We also show reduced efficiency when permits are bankable due to over-banking and when investments in emissions abatement are possible due to overinvesting. These tendencies do not worsen, however, when emissions caps decline.Emissions Trading, Investment in Abatement, Banking, Laboratory Experiments