An experiment was designed to compare ground‐based methods of nitrogen (N) stress detection with N stress detection using remote sensing. The study area, located in Minidoka, Idaho, is a 64 ha center pivot with a crop of Penawawa spring white wheat. Nitrogen was varied on four transects approximately 40 m wide and 805 m long. The N application rates chosen for the research were 0%, 40%, 100%, and 130% of normal. Nitrogen deficiency was quantified from tissue sampling, which was used as the response variable. Nitrogen was then measured or estimated at key stages in the wheat growth cycle using visual observation, a chlorophyll meter, and remotely‐sensed data. Visual observation was the normally‐employed method for area farmers. These methods of N stress detection were compared for accuracy, timeliness, usefulness, and cost. Remote sensing was comparable to the chlorophyll meter in accuracy. The chlorophyll meter was the timeliest method for obtaining a quantitative measurement.

The objective of this study is to evaluate remote sensing as a tool for measuring wheat nitrogen (N) content and then demonstrate how that information may be used by crop managers to improve grain protein content. Remote sensing data from aerial and satellite platforms were collected and compared with flag leaf N concentrations. Flag leaf N was significantly correlated with reflectance (r 2 = 0.52-0.80) during 2002 and 2003. A mid-season application of N increased grain protein in every treatment, but most significantly in the N-stressed treatments. Using remote sensing as a tool, wheat growers can estimate N stress and make decisions about protein management.

Many land‐management agencies are caught between decreased budgets and increasing public interest. Furthermore, semi‐arid landscapes are sensitive to management prescriptions and use, and require a significant amount of monitoring in order to assess vegetation productivity and health. The purpose of this study was to evaluate the use of Landsat Enhanced Thematic Mapper (ETM) Imagery to monitor seasonal vegetation cover in a shrub‐steppe ecosystem. The study area, managed by The Utah School and Institutional Trust Lands Administration, consists of a shrub‐steppe environment in south‐central Utah. Biotic (tree, shrub, grass, and forbs) and abotic (slope, aspect, elevation, landform type, and slope shape) data were collected during the 2001 growing season and compared with three dates of Landsat ETM satellite imagery. The relationships between remotely sensed parameters, photosynthetically active ground cover and bare ground were significant. Stepwise linear regression for total vegetation cover identified the ETM bands 2, 4, and 5 with NDVI as the strongest predictor variables (r2 = 0.86, p < 0.01). Combined predictor values for bare ground using ETM bands 3, 4, 5, and 7 with NDVI had a stronger relationship (r2 = 0.92, p < .01). Correlations between percent vegetation cover estimates versus ETM individual reflective bands and NDVI showed little relationship between vegetation cover and the NIR (band 4) but a strong relationship with NDVI for this semi‐arid landscape. Remote sensing information may be the key for public and private land mangers to make optimal economic and environmental decisions regarding use of state, public, and private rangelands.

Imagery from satellite sensors (IKONOS and QuickBird) were compared with information from a yield monitor to validate the usefulness of these geospatial technologies in predicting wheat grain yields under two non-uniform crop conditions. A center-pivot irrigated field of wheat under water stress was monitored by imagery from IKONOS and a yield monitor during the 2001 growing season. In another location, a field of wheat under dryland conditions was monitored with Quickbird satellite imagery and a yield monitor during the 2002 growing season. Yield maps were created from the yield monitor data and imagery were processed using NDVI and SAVI. Each method was compared for advantages and disadvantages. Yield monitor data are useful for determining patterns of crop growth and stress. Satellite imagery are useful for in-season analysis, but expensive and temporally limited. QuickBird satellite imagery were received within 10-15 days of acquisition during the 2002 growing season, rivaling the turnaround time of aerial imagery. This may indicate a promising future for the availability, effectiveness, and timeliness of satellite imagery.

This experiment was designed to compare ground-based methods of nitrogen (N) stress detection with methods using remote sensing information. The study area, located in Minidoka, Idaho, was a 64 ha (quarter section) center pivot with a crop of Penawawa spring white wheat. Nitrogen was varied on four transects approximately 40 m wide and 805 m long. The N application rates chosen for the research were 0%, 40%, 100%, and 130% of normal. Nitrogen deficiency was quantified from tissue sampling and estimated at key stages in the wheat growth cycle using visual observation, a chlorophyll meter, and remotely-sensed data. These methods of nitrogen stress detection were compared for accuracy, timeliness, usefulness, and cost. Remote sensing was comparable to the chlorophyll meter in accuracy. The chlorophyll meter was the timeliest method for obtaining a quantitative measurement. Remote sensing is the most economical method, assuming a provider preprocesses the imagery for the grower.

The design and execution of complex molecule synthesis centers upon those reactions that are truly versatile and reliable, especially those that form carbon-carbon bonds. For many decades, alkene metathesis reactions have found great application in polymer synthesis, but it has only been recently that this reaction is finding a place in the arsenal of the synthetic chemist. This new role for the olefin metathesis reaction is directly related to the recent development of stable, well-defined catalysts for this reaction. Ruthenium and molybdenum catalysts, among others, are finding wide spread use in organic synthesis. These catalysts are able to promote the exchange of two independent alkenes and result in the formation of a new olefin. The most common use for this reaction involves an intermolecular variation whereby a tethered diene is metathesized to form a cycloalkene. This ring-closing metathesis (RCM) process has been shown to be remarkably versatile and is tolerant to a wide range of accompanying functionality. RCM reactions are now widely used for the preparation of carbocyclic, azacyclic, and oxacyclic systems. This review focuses on the versatility offered by these well-defined catalyst systems and focuses on their use in the synthesis of natural and non-natural products.