On the Marginal Value of a Fish: Some Evidence from a Steelhead Fishery

Policymakers and other interested parties frequently request information on the recreational value of a fish. Although fishing valuation studies date back at least 25 years, most studies focus on the average value of a fish. If the purpose of such estimates is to measure the value of incremental changes in fish numbers, then use of average estimates may lead to an incorrect policy decisions. The objective of this analysis is to estimate the marginal value of a steelhead trout in a recreational fishery on the John Day River of Oregon. The study uses contingent valuation procedures to elicit willingness to pay estimates for improvements in fish numbers and success rates. For the anglers in this survey, the value of an additional steelhead is $6.65 under current catch conditions. This value is much lower than values currently used in public debates in the Pacific Northwest, but similar to some marginal values reported in the recent literature. Implications of these values relative to average values are discussed.Demand and Price Analysis, Environmental Economics and Policy, Research Methods/ Statistical Methods, Resource /Energy Economics and Policy,

EC76-1742 Guide to Community Forestry Planning

Extension Circular 76-1742 is a guide to community forestry planning

The Little Probe That Could! (A Story of Mission Impossible Engineering)

Starting with the Space Shuttle flight 4A (Nov. 30, 2000), the International Space Station (ISS) power system employs large, high voltage, solar arrays with the negative ground tied to chassis. An intense study by a NASA sponsored Tiger Team in the early ‘90s determined that this configuration leads to the structure being at a high negative potential relative to the local plasma (approximately 140v negative without any intervention) and, that at any potential greater than around 70v negative, the anodized aluminum structure and its components will undergo destructive arcing. A set of plasma contactor units (PCUs) was deployed to provide a conductive xenon plasma path for remitting electrons collected by the arrays and thus bring the potential closer to zero and mitigate the arcing danger. In late July 2000, the ISS program office at JSC issued an engineering change notice that directed the development of some means to independently assess the performance of the PCU’s, and to have hardware available for launch on STS-97 (ISS Flight 4A) the very mission scheduled to deliver and install the first set of large Station solar arrays on November 30th. This allowed only a mere 4.5 months to design, build, test, manifest, complete EVA training, and deliver for launch. NASA Glenn, NASA Johnson, and Design_Net Engineering formed a unique team to try to accomplish the directive. The subject of this paper is to describe the Floating Potential Probe (FPP) and the fast-track program approach used to quickly develop this autonomous system for measuring the electrical potential between the ISS and the surrounding space plasma. At the time, most people involved with the Floating Potential Probe (FPP) project believed that there was less than a 10% chance of successfully making it onboard Flight 4A and even less chance that it would work

Cdc53p acts in concert with Cdc4p and Cdc34p to control the G1 to S phase transition and identifies a conserved family of proteins

Regulation of cell cycle progression occurs in part through the targeted degradation of both activating and inhibitory subunits of the cyclin-dependent kinases. During G1, CDC4, encoding a WD-40 repeat protein, and CDC34, encoding a ubiquitin-conjugating enzyme, are involved in the destruction of these regulators. Here we describe evidence indicating that CDC53 also is involved in this process. Mutations in CDC53 cause a phenotype indistinguishable from those of cdc4 and cdc34 mutations, numerous genetic interactions are seen between these genes, and the encoded proteins are found physically associated in vivo. Cdc53p defines a large family of proteins found in yeasts, nematodes, and humans whose molecular functions are uncharacterized. These results suggest a role for this family of proteins in regulating cell cycle proliferation through protein degradation

Variations in gravel bed composition of small streams in the Oregon Coast Range

A study of the temporal and spatial variability of stream gravel bed composition and the factors affecting the amount of fine sediment within the bed was conducted in the streams of the Oregon Coast Range. Streambed samples were obtained by frozen core techniques and the amount of sediment smaller than 1.0 mm in diameter was expressed as a percentage by weight of the total sample. The amount of fine sediment in stream gravel beds was found to be highly variable in time and space. Temporal variability in percent fines was caused by flushing of fines from the gravel beds during high streamfiow events. This flushing of fine sediment seemed to occur randomly during winter freshets. Seven of 13 total streambed sample locations on five small streams showed trends of decreasing amounts of fine sediment during the winter high streamflow season. The percent fines within the stream bed was also found to display large variation (a) between streams, (b) between locations in the same stream, and (c) between locations in the same riff 1. Bed samples were collected on 21 watersheds in the Coast Range during the summer of 1978. The amount of fine sediment averaged 19.4% and ranged from 10.6% to 29.4%. Comparisons between locations on the same stream showed bed composition to be highly variable. Approximately 75% of the bed composition comparisons were significantly different at the 95% confidence level. One gravel bed was sampled on a 1.2 by 1.2 m grid design and significant (95% confidence level) changes in percent fines were found to exist both perpendicular and parallel to the stréamflow in this small area of the stream. Regression analysis on the samples collected on the 21 streams indicated that the amount of fine sediment in the bed is influenced by the slope, area, relief, and land use characteristics of the watershed. Within a single stream, however, regression analysis indicated that gravel bed composition was dependent on sinuosity and ankful1 stage. These two variables suggest that the intrusion of fines into the stream bed is influenced locally by hydraulic conditions within the channel. Regression analysis and field observations suggest that the amount of fine sediment in stream gravel beds might be increased by road construction and logging operations. However, increases in levels of bed fines after disturbance should be temporary due to the flushing of fines with high flows.Keywords: Oregon Coast Range, Bed sediments, Stream channels, Sedimentation, Water quality, Forest harvestin

Quantitative Diagnosis and Prognosis Framework for Concrete Degradation Due to Alkali- Silica Reaction

This research is seeking to develop a probabilistic framework for health diagnosis and prognosis of aging concrete structures in nuclear power plants that are subjected to physical, chemical, environment, and mechanical degradation. The proposed framework consists of four elements: monitoring, data analytics, uncertainty quantification, and prognosis. The current work focuses on degradation caused by ASR (alkali-silica reaction). Controlled concrete specimens with reactive aggregate are prepared to develop accelerated ASR degradation. Different monitoring techniques—infrared thermography [1], digital image correlation (DIC), mechanical deformation measurements, nonlinear impact resonance acoustic spectroscopy [2] (NIRAS), and vibro-acoustic modulation [3] (VAM)—are studied for ASR diagnosis of the specimens. Both DIC and mechanical measurements record the specimen deformation caused by ASR gel expansion. Thermography is used to compare the thermal response of pristine and damaged concrete specimens and generate a 2-D map of the damage (i.e., ASR gel and cracked area), thus facilitating localization and quantification of damage. NIRAS and VAM are two separate vibration-based techniques that detect nonlinear changes in dynamic properties caused by the damage. The diagnosis results from multiple techniques are then fused using a Bayesian network, which also helps to quantify the uncertainty in the diagnosis. Prognosis of ASR degradation is then performed based on the current state of degradation obtained from diagnosis, by using a coupled thermo-hydro-mechanical-chemical (THMC) model [4] for ASR degradation. This comprehensive approach of monitoring, data analytics, and uncertainty-quantified diagnosis and prognosis will facilitate the development of a quantitative, risk-informed framework that will support continuous assessment and risk management of structural health and performance

Low-Dose TOF-PET Based on Surface Electron Production in Dielectric Laminar MCPs

We present simulations of whole-body low-dose time-of-flight positron emission tomography (TOF-PET) based on the direct surface production [1] by 511 keV gamma rays of energetic electrons via the Photo-electric and Compton Effects, eliminating the scintillator and photodetector sub-systems in PET scanners. In Ref. [1] we described Microchannel Plates (MCP) constructed from thin dielectric laminae containing heavy nuclei such as lead or tungsten (LMCP$^{\rm{TM}}$). The laminae surfaces are micro-patterned to form channels, which can then be functionalized to support secondary electron emission in the manner of conventional MCPs. We have simulated direct conversion using modifications to the TOPAS Geant4-based tool kit. A 20 $\times$ 20 $\times$ 2.54 cm$^3$ LMCP, composed of 150-micron thick lead-glass laminae, is predicted to have a $\ge 30$% conversion efficiency to a primary electron that penetrates an interior wall of a pore. The subsequent secondary electron shower is largely confined to one pore and can provide high space and time resolutions. In whole-body PET scanners the technique eliminates the scintillator and photodetector subsystems. The consequent absence of a photocathode allows assembly of large arrays at atmospheric pressure and less stringent vacuum requirements, including use of pumped and cycled systems. TOPAS simulations of the Derenzo and XCAT-brain phantoms are presented with dose reductions of factors of 100 and 1000 from a literature benchmark. New applications of PET at a significantly lower radiation dose include routine screening for early detection of pathologies, the use in diagnostics in previously unserved patient populations such as children, and a larger installed facility base in rural and under-served populations, where simpler gamma detectors and lower radiation doses may enable small low-cost portable PET scanners.Comment: Version 9d incorporates reviewer comments during revision process. 22 pages, 18 figure