Mapping wildfire and clearcut harvest disturbances in boreal forests with Landsat time series data

Information regarding the extent, timing and magnitude of forest disturbance are key inputs required for accurate estimation of the terrestrial carbon balance. Equally important for studying carbon dynamics is the ability to distinguish the cause or type of forest disturbance occurring on the landscape. Wildfire and timber harvesting are common disturbances occurring in boreal forests, with each having differing carbon consequences (i.e., biomass removed, recovery rates). Development of methods to not only map, but distinguish these types of disturbance with satellite data will depend upon an improved understanding of their distinctive spectral properties. In this study, we mapped wildfires and clearcut harvests occurring in a Landsat time series (LTS) acquired in the boreal plains of Saskatchewan, Canada. This highly accurate reference map (kappa = 0.91) depicting the year and cause of historical disturbances was used to determine the spectral and temporal properties needed to accurately classify fire and clearcut disturbances. The results showed that spectral data from the short-wave infrared (SWIR; e.g., Landsat band 5) portion of the electromagnetic spectrum was most effective at separating fires and clearcut harvests possibly due to differences in structure, shadowing, and amounts of exposed soil left behind by the two disturbance types. Although SWIR data acquired 1 year after disturbance enabled the most accurate discrimination of fires and clearcut harvests, good separation (e.g., kappa ≥ 0.80) could still be achieved with Landsat band 5 and other SWIR-based indices 3 to 4 years after disturbance. Conversely, minimal disturbance responses in near infrared-based indices associated with green leaf area (e.g., NDVI) led to unreliably low classification accuracies regardless of time since disturbance. In addition to exploring the spectral and temporal manifestation of forest disturbance types, we also demonstrate how Landsat change maps which attribute cause of disturbance can be used to help elucidate the social, ecological and carbon consequences associated with wildfire and clearcut harvesting in Canadian boreal forests.     

Psychology for the public: A content analysis of Psychology Today..

Surveyed the extent to which Psychology Today (PT) has maintained an empirical basis for its articles and the degree to which psychologists and individuals with doctorates have been responsible for PT articles. Two samples of PT were selected for review by 2 raters (the present authors). Findings indicate that not only have PT articles significantly shifted away from a presentation of empirically based data, but the proportion of articles authored by psychologists, as well as the educational level of authors, has declined, particularly in the last 3 yrs. (4 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Leucaena (Leucaena leucocephala (Lam) de Wit) prunings as nitrogen source for maize (Zea mays L.)

The effectiveness ofLeucaena leucocephala (Lam.) de Wit, prunings as N source for maize (Zea mays L.) was evaluated in field and pot trials at Ibadan, southern Nigeria. An N deficient, sandy Apomu soil (Psammentic Usthorthent) was used. The prunings significantly increased N uptake of seedlings and N percentage in ear leaves of maize. High maize gain yield was obtained with application of 10 tons fresh prunings or a combination of 5 tons fresh prunings and N at 50 kg ha^–1. The prunings as N source, appeared to be more effective when incorporated in the soil than when applied as mulch. In the pot trial, prunings applied two weeks before planting was more effective than when applied at time of planting maize. Under screen house conditions, the apparent N recovery from prunings with early incorporation about equals that of fertilizer N.     

A quantitative look at software licensing for IT managers

Information vendors, buyers, and users often take the approach that the number of employees equals the number of licensed users. Unfortunately, although assuring virtually unlimited usage of the software or database, this approach can also come with an unlimited cost. A typical vendor contract might read something to the effect that "Vendor A agrees to provide unlimited access to database B for all 200 employees of Firm Z," a relatively straightforward approach. However, there is no logical reason to pay for unused information and access.     

Retardation of Dredged Material Leachate in Foundation Soils

Contaminated dredged material is often placed in confined disposal facilities (CDFs) designed and managed to control environmental impacts of the disposed sediment. This note presents equations for use in a screening procedure to evaluate the impact of a CDF on groundwater. The hydrologic evaluation of leachate production and quality model was used to simulate leachate production and transport through the foundation considering a range of foundation soil characteristics and contaminant properties. The model results were used to develop predictive equations of contaminant attenuation and travel time in the foundation soils. When used with equations to predict dispersion in the aquifer, contaminant exposures at receptor locations can be predicted, which is essential in leachate screening applications. The approach does not consider degradation or permanent sequestration of contaminants. Therefore, the procedure is conservative in that it may overestimate actual leachate concentrations and underestimate actual travel times.     

Effects of thermal processing and iron doping in co-sputtered barium strontium titanate thin films

The effects of the thermal processing and iron doping on RF magnetron co-sputtered barium strontium titanate thin film properties have been investigated. X-ray diffraction and Raman spectroscopy have been used to determine the structural evolution of the films as a function of the annealing temperature and the amount of iron dopant. X-ray photoelectron spectroscopy and electron paramagnetic resonance spectroscopy were employed to gain information about the chemical binding states and the defect structure. The enhancement of the quality factor Q, as well as the decreasing permittivity and tunability due to iron acceptor doping are demonstrated.