Coupled abiotic-biotic mineralization of 2,4,6-trinitrotoluene (TNT) in soil slurry

The explosive 2,4,6-trinitrotoluene (TNT) is a contaminant of soils and ground waters worldwide. To help alleviate such environmental contamination, we investigated a coupled abiotic-biotic treatment scheme for remediating TNT-contaminated soil in slurry solutions. Two types of soil were used (sandy and silt loam) to simulate different soils that might be found at actual sites. These soils were subsequently contaminated with 5000 mg kg(-1) TNT. Mineralization of TNT was initially optimized for minimum reactant use (Fe(3+) and H(2)O(2)) and maximum soil slurry percentage (percent solids) using modified Fenton reactions conducted in the absence of light followed by the addition of an uncharacterized aerobic biomass. Greater than 97% TNT degradation was observed under optimum reaction conditions for both soils. Using two optimum reactant concentrations for each soil, coupled abiotic-biotic reactions showed an increase in TNT mineralization, from 41 to 73% and 34 to 64% in the sandy soil (10 and 20% slurry, respectively, 1470 mM H(2)O(2)), and increases from 12 to 23% and 13 to 28% in the silt loam soil (5% slurry, 294 and 1470 mM H(2)O(2), respectively). These results show promise in the use of combined abiotic-biotic treatment processes for soils contaminated with high concentrations of TNT.     

Place attachment and place identity in natives and non-natives

Place attachment is an affective bond that people establish with specific areas where they prefer to remain and where they feel comfortable and safe. Place identity, however, has been defined as a component of personal identity, a process by which, through interaction with places, people describe themselves in terms of belonging to a specific place. Most research has observed positive correlations between these variables in populations that have maintained ongoing interactions over long periods of time. This work presents two studies in which we compare place attachment to place identity in samples differentiated according to birthplace and length of residence, and the magnitude of these bonds to different places. The results of the first study revealed differences between intensity of attachment and identity depending on place of origin and place assessed. The second study found that identity and attachment tend to coincide in natives, while individuals from other places give higher scores for attachment than for identity. Results from the two studies have enabled us to consider that place attachment develops before place identity, at least in the case of the non-natives. Both studies reveal that bonds are stronger with the city than with the neighbourhood, but that attachment and identity with the island are stronger than either of them.     

Über krystallisierte Acetylcellulose

The Science of Nature -     

Conservation Corridors and Contagious Disease: A Cautionary Note

Recent conservation proposals frequently include the establishment of corridors to connect isolated patches of wildlife habitat. Much attention has been focused on the potential benefits of corridors with little note given to potentially adverse consequences. A simulation model is developed here to study the effect of corridors on the survival of a metapopulation in the presence of a fatal disease that is spread by direct contact between susceptible and infected individuals. For the disease modeled here, a landscape of patches connected by corridors generally suffers fewer metapopulation extinctions than a landscape of isolated patches. However, under a narrow range of conditions, results suggest that corridors may dramatically increase the probability of metapopulation extinction. This occurs when disease-induced mortality is low enough to allow infected individuals to spread the disease, but high enough to reduce population levels to the point that random demographic and environmental events cause frequent metapopulation extinctions. This has important implications for the design and management of conservation reserve networks. Although discussion focuses primarily on conservation corridors, the model results apply to any management techniques that increase the movement of individuals among populations.     

Random forests for classification in ecology

Classification procedures are some of the most widely used statistical methods in ecology. Random forests (RF) is a new and powerful statistical classifier that is well established in other disciplines but is relatively unknown in ecology. Advantages of RF compared to other statistical classifiers include (1) very high classification accuracy; (2) a novel method of determining variable importance; (3) ability to model complex interactions among predictor variables; (4) flexibility to perform several types of statistical data analysis, including regression, classification, survival analysis, and unsupervised learning; and (5) an algorithm for imputing missing values. We compared the accuracies of RF and four other commonly used statistical classifiers using data on invasive plant species presence in Lava Beds National Monument, California, USA, rare lichen species presence in the Pacific Northwest, USA, and nest sites for cavity nesting birds in the Uinta Mountains, Utah, USA. We observed high classification accuracy in all applications as measured by cross-validation and, in the case of the lichen data, by independent test data, when comparing RF to other common classification methods. We also observed that the variables that RF identified as most important for classifying invasive plant species coincided with expectations based on the literature.     

Effective Protection of Open Space: Does Planning Matter?

High quality plans are considered a crucial part of good land use planning and often used as a proxy measure for success in plan implementation and goal attainment. We explored the relationship of open space plan quality to the implementation of open space plans and attainment of open space protection goals in Research Triangle, North Carolina, USA. To measure plan quality, we used a standard plan evaluation matrix that we modified to focus on open space plans. We evaluated all open space plans in the region that contained a natural resource protection element. To measure plan implementation and open space protection, we developed an online survey and administered it to open space planners charged with implementing the plans. The survey elicited each planner’s perspective on aspects of open space protection in his or her organization. The empirical results (1) indicate that success in implementation and attaining goals are not related to plan quality, (2) highlight the importance of when and how stakeholders are involved in planning and implementation processes, and (3) raise questions about the relationship of planning to implementation. These results suggest that a technically excellent plan does not guarantee the long-term relationships among local landowners, political and appointed officials, and other organizations that are crucial to meeting land protection goals. A greater balance of attention to the entire decision process and building relationships might lead to more success in protecting open space.     

84th Annual Meeting & Exhibition

ABSTRACT

Machining swarf is a finely divided metal powder that is prone to spontaneous heating and, in some cases, spontaneous combustion. The fine particle size, large amount of particle surface area, and the presence of moisture all promote rapid oxidation. This hazard dramatically increases disposal costs for swarf and interferes with recycling efforts. A potential method for minimizing spontaneous heating and facilitating recycling of the swarf is to spray a fluid on the material that coats the particles and creates a barrier between the metal and oxygen. Surface coatings could be tested for their effects on the spontaneous heating potential of swarf by treating a sample of swarf with a fluid that would coat the particles, then monitoring its heating behavior. This paper describes the results of applying corrosion inhibitors and machining fluids to the swarf, and monitoring the spontaneous heating behavior using a testing method developed specifically for this purpose. The effects of different types of surfactants and the effects of surfactant concentration on the spontaneous heating of swarf are discussed.