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In this article, we develop a two-factor model of commodity prices that allows meanreversion in short-term prices and uncertainty in the equilibrium level to which prices revert. Although these two factors are not directly observable, they may be estimated from spot and futures prices. Intuitively, movements in prices for long-maturity futures contracts(More)
The hazards associated with pathogens in land-applied animal and human wastes have long been recognized. Management of these risks requires an understanding of sources, concentrations, and removal by processes that may be used to treat the wastes; survival in the environment; and exposure to sensitive populations. The major sources are animal feeding(More)
Tomato mosaic tobamovirus is a very stable plant virus with a wide host range, which has been detected in plants, soil, water, and clouds. Because of its stability and prevalence in the environment, we hypothesized that it might be preserved in ancient ice. We detected tomato mosaic tobamovirus RNA by reverse-transcription polymerase chain reaction(More)
Uncertainty is an important consideration for both developers and users of environmental simulation models. Establishing quantitative estimates of uncertainty for deterministic models can be difficult when the underlying bases for such information are scarce. We demonstrate an application of probabilistic uncertainty analysis that provides for refinements(More)
(2009) Human-machine interaction issues in quality control based on on-line image classification. Refereed: Yes c 2009 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale(More)
Approximately 37% of forestlands in the conterminous United States are publicly owned; they represent a substantial area of potential carbon sequestration in US forests and in forest products. However, large areas of public forestlands traditionally have been less intensively inventoried than privately owned forests. Thus, less information is available(More)
BACKGROUND Standing dead trees are one component of forest ecosystem dead wood carbon (C) pools, whose national stock is estimated by the U.S. as required by the United Nations Framework Convention on Climate Change. Historically, standing dead tree C has been estimated as a function of live tree growing stock volume in the U.S.'s National Greenhouse Gas(More)
In surface inspection applications, the main goal is to detect all areas which might contain defects or unacceptable imperfections, and to classify either every single ‘suspicious’ region or the investigated part as a whole. After an image is acquired by the machine vision hardware, all pixels that deviate from a pre-defined ‘ideal’ master image are set to(More)
The inventory and monitoring of coarse woody debris (CWD) carbon (C) stocks is an essential component of any comprehensive National Greenhouse Gas Inventory (NGHGI). Due to the expense and difficulty associated with conducting field inventories of CWD pools, CWD C stocks are often modeled as a function of more commonly measured stand attributes such as live(More)
A greenhouse gas and carbon accounting profile was developed for the U.S. forest products industry value chain for 1990 and 2004-2005 by examining net atmospheric fluxes of CO(2) and other greenhouse gases (GHGs) using a variety of methods and data sources. Major GHG emission sources include direct and indirect (from purchased electricity generation)(More)