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

Superorbital Period in the High Mass X-ray Binary 2S 0114+650

We report the detection of a superorbital period in the high-mass X-ray binary 2S 0114+650. Analyses of data from the Rossi X-ray Timing Explorer (RXTE) All-Sky Monitor (ASM) from 1996 January 5 to 2004 August 25 reveal a superorbital period of 30.7 +/- 0.1 d, in addition to confirming the previously reported neutron star spin period of 2.7 h and the binary orbital period of 11.6 d. It is unclear if the superorbital period can be ascribed to the precession of a warped accretion disc in the system.Comment: 5 pages, 5 figures, submitted to MNRAS 27th January 2005. Manuscript expanded to include discussion of evolution of periods, and hardness ratio variability. Number of figures increased from 5 to 9. Accepted for publication 19th December 200

The window of visibility: A psychological theory of fidelity in time-sampled visual motion displays

Many visual displays, such as movies and television, rely upon sampling in the time domain. The spatiotemporal frequency spectra for some simple moving images are derived and illustrations of how these spectra are altered by sampling in the time domain are provided. A simple model of the human perceiver which predicts the critical sample rate required to render sampled and continuous moving images indistinguishable is constructed. The rate is shown to depend upon the spatial and temporal acuity of the observer, and upon the velocity and spatial frequency content of the image. Several predictions of this model are tested and confirmed. The model is offered as an explanation of many of the phenomena known as apparent motion. Finally, the implications of the model for computer-generated imagery are discussed

Procedures for estimating the effects of design and operational characteristics of jet aircraft on ground noise

Estimation procedures for effect of design and flight characteristics of jets on ground nois