8,843 research outputs found
Development of techniques for producing static strata maps and development of photointerpretation methods based on multitemporal LANDSAT data
The progress of research conducted in support of the Large Area Crop Inventory Experiment (LACIE) is documented. Specific tasks include (1) evaluation of the static stratification procedure and modification of that procedure if warranted, and (2) the development of alternative photointerpretative techniques to the present LACIE procedures for the identification and selection of training fields (areas)
Application of remote sensing to selected problems within the state of California
There are no author-identified significant results in this report
Application of remote sensing to selected problems within the state of California
There are no author-identified signficant results in this report
Development of techniques for producing static strata maps and development of photointerpretive methods based on multitemporal LANDSAT data
Progress in the evaluation of the static stratification procedure and the development of alternative photointerpretive techniques to the present LACIE procedure for the identification of training fields is reported. Statistically significant signature controlling variables were defined for use in refining the stratification procedure. A subset of the 1973-74 Kansas LACIE segments for wheat was analyzed
Gaussian approximations for stochastic systems with delay: chemical Langevin equation and application to a Brusselator system
We present a heuristic derivation of Gaussian approximations for stochastic
chemical reaction systems with distributed delay. In particular we derive the
corresponding chemical Langevin equation. Due to the non-Markovian character of
the underlying dynamics these equations are integro-differential equations, and
the noise in the Gaussian approximation is coloured. Following on from the
chemical Langevin equation a further reduction leads to the linear-noise
approximation. We apply the formalism to a delay variant of the celebrated
Brusselator model, and show how it can be used to characterise noise-driven
quasi-cycles, as well as noise-triggered spiking. We find surprisingly
intricate dependence of the typical frequency of quasi-cycles on the delay
period.Comment: 14 pages, 9 figure
CEO Compensation Structure following Succession: Evidence of Optimal Incentives with Career Concerns
To motivate managers to pursue shareholder interests, boards may design management compensation packages to reward managers for good firm performance. However, note that when CEOs are far from retirement, they have career concerns. In these cases, Gibbons and Murphy argue that it may not be optimal for their current compensation to be too dependent on firm performance. Testing this proposition, we find that abnormal returns are negatively related to the percentage of performance-based pay of newly hired CEOs when companies announce CEO successions. Since these newly hired CEOs are likely some distance from retirement, we interpret these results as being consistent with Gibbons and Murphy; it may be better to allow newly hired CEOs to be paid in human capital increases from the managerial labor market than to have their current pay too closely related to performance
Study of Surface Morphology, Elemental Composition and Sources of Airborne Fine Particulate Matter in Agbara Industrial Estate, Nigeria
Ambient atmospheric fine particle emission contribution to industrial pollution load is hard to quantify due to absence of air quality monitoring stations and difficulties in assessing suitable analytical instruments. Therefore, to keep abreast of air quality information, the use of physicochemical signatures to assess the sources of elements associated with fine particulate matter in Agabra Industrial Estate was explored with Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-ray (EDX) and Principal Component Analysis (PCA). A greater proportion of Si and C were observed in the particles amongst other detected elements by EDX. Morphology results by SEM confirmed soot, alumino silicate and irregular shape mineral particles as the most common inhalable particles. Prominent among emission sources identified are industries, automobile exhaust, fugitive dust and solid waste combustion. The research suggests that adequate public awareness, industrial compliance, vehicle emission control, smooth operation of municipal solid waste incineration and government regulation will significantly reduce fine particulate pollution
Trace Metals Levels in Inorganic Fertilizers Commercially Available in Nigeria
Aims: To investigate the concentrations of arsenic (As), cadmium (Cd), copper (Cu), lead
(Pb), nickel (Ni), vanadium (V) and zinc (Zn) in commercially available inorganic fertilizers
(calcium superphosphate and urea).
Place and Duration of Study: Urea and superphosphate fertilizers were purchased from
a local market in Uyo, Southern Nigeria.
Methodology: A total of twenty seven fertilizer samples were randomly taken
representing triplicate samples from three urea and six superphosphate original fertilizer
bags. Each sample were digested and extracted using the ethylenediamine tetraacetic
acid (EDTA) extraction technique. The elemental analysis was performed using an
inductively coupled plasma atomic emission spectrophotometer (ICP-AES) (Optima 3000
– Perkin Elmer).
Results: The analyses indicated the presence of trace metals in commercially available
fertilizers sold in Nigeria. Cadmium was found in comparatively high concentrations. Zinc
was found present in relatively high concentrations in both urea and phosphate fertilizer
samples but As was found in low concentration. By comparison, the superphosphat
Analytical Relevance of Trace Metal Speciation in Environmental and Biophysicochemical Systems
This article presents a review of the analytical relevance of trace metal speciation analysis, which must be considered in environmental and biophysicochemical systems for reliable and efficient assessment and monitoring of trace metals. Examples are given of methodological approaches used for speciation analysis. An overview of speciation analysis in sediments, aquatic ecosystems and agrosystems is also presented
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