Trichloroethylene fate and transport studies and biodegradation kinetics in the saturated zone

Permeable reactive barriers (PRB) are constructed from soil solid amendments to support the growth of bacteria that are capable of degrading organic contaminants. The objective of this study was to identify low-cost soil solid amendments that could retard the movement of trichloroethylene (TCE) while serving as long-lived carbon sources to foster its biodegradation in shallow groundwater through the use of a PRB. The natural amendments high in organic carbon content such as eucalyptus mulch, compost, wetland peat, organic humus were compared based on their geophysical characteristics, such as pHw, porosity and total organic carbon (TOC), and as well as TCE sorption potentials. The pHw values were within neutral range except for pine bark mulch and wetland peat. All other geophysical characteristics of the amendments showed suitability for use in a PRB. While the Freundlich model showed better fit for compost and pine bark mulch, the linear sorption model was adequate for eucalyptus mulch, wetland peat and Everglades muck within the concentration range studied (0.2-0.8 mg/L TCE). According to these results, two composts and eucalyptus mulch were selected for laboratory column experiments to evaluate their effectiveness at creating and maintaining conditions suitable for TCE anaerobic dechlorination. The columns were monitored for pH, ORP, TCE degradation, longevity of nutrients and soluble TOC to support TCE dechlorination. Native bacteria in the columns had the ability to convert TCE to DCEs; however, the inoculation with the TCE-degrading culture greatly increased the rate of biodegradation. This caused a significant increase in by-product concentration, mostly in the form of DCEs and VC followed by a slow degradation to ethylene. Of the tested amendments eucalyptus mulch was the most effective at supporting the TCE dechlorination. The experimental results of TCE sequential dechlorination took place in eucalyptus mulch and commercial compost from Savannah River Site columns were then simulated using the Hydrus-1D model. The simulations showed good fit with the experimental data. The results suggested that sorption and degradation were the dominant fate and transport mechanisms for TCE and DCEs in the column, supporting the use of these amendments in a permeable reactive barrier to remediate the TCE.

Inter-subjective and transnational racial effects: The role of the United States in the formation and evolution of the collective perception and racial relations in Cuba, 1898–1902

Since the arrival of the first African slaves to Cuba in 1524, the issue of race has had a long-lived presence in the Cuban national discourse. However, despite Cuba’s colonial history, it has often been maintained by some historians that race relations in Cuba were congenial with racism and racial discrimination never existing as deep or widespread in Cuba as in the United States (Cannon, 1983, p. 113). In fact, it has been argued that institutionalized racism was introduced into Cuban society with the first U.S. occupation, during 1898–1902 (Cannon, 1983, p. 113). This study of Cuba investigates the influence of the United States on the development of race relations and racial perceptions in post-independent Cuba, specifically from 1898-1902. These years comprise the time period immediately following the final fight for Cuban Independence, culminating with the Cuban-Spanish-American War and the first U.S. occupation of Cuba. By this time, the Cuban population comprised Africans as well as descendants of Africans, White Spanish people, indigenous Cubans, and offspring of the intermixing of the groups. This research studies whether the United States’ own race relations and racial perceptions influenced the initial conflicting race relations and racial perceptions in early and post-U.S. occupation Cuba. This study uses a collective interpretative framework that incorporates a national level of analysis with a race relations and racial perceptions focus. This framework reaches beyond the traditionally utilized perspectives when interpreting the impact of the United States during and following its intervention in Cuba. Attention is given to the role of the existing social, political climate within the United States as a driving influence of the United States’ involvement with Cuba. This study reveals that emphasis on the role of the United States as critical to the development of Cuba’s race relations and racial perceptions is credible given the extensive involvement of the U.S. in the building of the early Cuban Republic and U.S. structures serving as models for reconstruction. U.S. government formation in Cuba aligned with a governing system reflecting the existing governing codes of the U.S. during that time period.

Cross-Cultural Cuisine: Long-Term Trend or Short-Lived Fad

Defining a consumer interest as a long-term trend or short-lived fad has significant implicatiosn for restauranteurs' management decisions. The terms "trend" and "fad" can be operationally defined for the food service industry. The authors examine today's popular cross-cultural cuisine to determine its trend or fad status and discuss the catalysts that promoted or hindered its trend/fad status, as well as implications for the food service industry.