Characterization, sources, and transformations of dissolved organic matter (DOM) in Florida coastal Everglades (FCE)

Dissolved organic matter (DOM) is one of the largest carbon reservoirs on this planet and is present in aquatic environments as a highly complex mixture of organic compounds. The Florida coastal Everglades (FCE) is one of the largest wetlands in the world. DOM in this system is an important biogeochemical component as most of the nitrogen (N) and phosphorous (P) are in organic forms. Achieving a better understanding of DOM dynamics in large coastal wetlands is critical, and a particularly important issue in the context of Everglades restoration. In this work, the environmental dynamics of surface water DOM on spatial and temporal scales was investigated. In addition, photo- and bio-reactivity of this DOM was determined, surface-to-groundwater exchange of DOM was investigated, and the size distribution of freshwater DOM in Everglades was assessed. The data show that DOM dynamics in this ecosystem are controlled by both hydrological and ecological drivers and are clearly different on spatial scales and variable seasonally. The DOM reactivity data, modeled with a multi-pool first order degradation kinetics model, found that fluorescent DOM in FCE is generally photo-reactive and bio-refractory. Yet the sequential degradation proved a “priming effect” of sunlight on the bacterial uptake and reworking of this subtropical wetland DOM. Interestingly, specific PARAFAC components were found to have different photo- and bio-degradation rates, suggesting a highly heterogeneous nature of fluorophores associated with the DOM. Surface-to-groundwater exchange of DOM was observed in different regions of the system, and compositional differences were associated with source and photo-reactivity. Lastly, the high degree of heterogeneity of DOM associated fluorophores suggested based on the degradation studies was confirmed through the EEM-PARAFAC analysis of DOM along a molecular size continuum, suggesting that the fluorescence characteristics of DOM are highly controlled by different size fractions and as such can exhibit significant differences in reactivity.

Raising Cane in the 'Glades: The Global Sugar Trade and the Transformation of Florida

Over the last century, the Everglades underwent a metaphorical and ecological transition from impenetrable swamp to endangered wetland. At the heart of this transformation lies the Florida sugar industry, which by the 1990s was at the center of the political storm over the multi-billion dollar ecological “restoration” of the Everglades. Raising Cane in the ’Glades is the first study to situate the environmental transformation of the Everglades within the economic and historical geography of global sugar production and trade. Using, among other sources, interviews, government and corporate documents, and recently declassified U.S. State Department memoranda, Gail M. Hollander demonstrates that the development of Florida’s sugar region was the outcome of pitched battles reaching the highest political offices in the U.S. and in countries around the world, especially Cuba—which emerges in her narrative as a model, a competitor, and the regional “other” to Florida’s “self.” Spanning the period from the age of empire to the era of globalization, the book shows how the “sugar question”—a label nineteenth-century economists coined for intense international debates on sugar production and trade—emerges repeatedly in new guises. Hollander uses the sugar question as a thread to stitch together past and present, local and global, in explaining Everglades transformation.

Crayfish assemblage shifts in a large drought-prone wetland: the roles of hydrology and competition

1. Faster growing, larger and/or more aggressive crayfish species are predicted to dominate permanent waterbodies. We tested this prediction using a 9 year dataset for two species of crayfish (Procambarus alleni and Procambarus fallax) co-existing in a sub-tropical flowing slough in southern Florida. Using a series of laboratory and mesocosm experiments we also compared life history traits and performance of the respective species to test mechanisms that could explain dominance shifts in the local crayfish assemblages. 2. Over the 9-year period, P. alleni densities were the greatest in shallower, shorterhydroperiod areas bordering the slough, while P. fallax densities were higher in deeper, longer-hydroperiod central areas. These areas were separated by 0.8–2 km of continuous wetland with no apparent barriers to movement between them. 3. Density of P. fallax was not strongly affected by any measures of hydrological variation, while P. alleni density increased with more severe drought conditions. Following the strongest droughts, P. alleni colonized areas in the centre of the slough where they had been absent or scarce in wetter years. 4. We conducted experiments to compare growth rates, drought tolerance, and competitive dominance of these species. P. alleni survived drought conditions better, had higher growth rates, and was the dominant competitor for space and food. While drought probably limits P. fallax in the drier slough habitats, neither drought sensitivity nor interspecific competition with P. fallax can explain decreases of P. alleni with wetter conditions. 5. Our results indicate that a competition-colonization tradeoff cannot explain the crayfish compositional dynamics in this wetland because P. alleni is both the best competitor and the best at surviving in and colonizing areas with the strongest droughts. Future attention should focus on the potential for selective effects of predators that co-vary with hydrology. 6. The traits (large size, fast growth, competitive dominance) exhibited by P. alleni, which is absent in long-hydroperiod wetlands, are those exhibited by dominant crayfish in permanent lakes and streams containing fish. Although these traits make crayfish less vulnerable to fish in some lakes and streams, life-history models of community structure across permanence gradients suggest the opposite traits should be favoured for co-existence with fish.

Dynamic modeling and analysis of single-stage boost inverters under normal and abnormal conditions

Inverters play key roles in connecting sustainable energy (SE) sources to the local loads and the ac grid. Although there has been a rapid expansion in the use of renewable sources in recent years, fundamental research, on the design of inverters that are specialized for use in these systems, is still needed. Recent advances in power electronics have led to proposing new topologies and switching patterns for single-stage power conversion, which are appropriate for SE sources and energy storage devices. The current source inverter (CSI) topology, along with a newly proposed switching pattern, is capable of converting the low dc voltage to the line ac in only one stage. Simple implementation and high reliability, together with the potential advantages of higher efficiency and lower cost, turns the so-called, single-stage boost inverter (SSBI), into a viable competitor to the existing SE-based power conversion technologies.^ The dynamic model is one of the most essential requirements for performance analysis and control design of any engineering system. Thus, in order to have satisfactory operation, it is necessary to derive a dynamic model for the SSBI system. However, because of the switching behavior and nonlinear elements involved, analysis of the SSBI is a complicated task.^ This research applies the state-space averaging technique to the SSBI to develop the state-space-averaged model of the SSBI under stand-alone and grid-connected modes of operation. Then, a small-signal model is derived by means of the perturbation and linearization method. An experimental hardware set-up, including a laboratory-scaled prototype SSBI, is built and the validity of the obtained models is verified through simulation and experiments. Finally, an eigenvalue sensitivity analysis is performed to investigate the stability and dynamic behavior of the SSBI system over a typical range of operation. ^

Marketing A Hospitality Program And Its Product

In his dialogue entitled - Marketing A Hospitality Program and Its Product - Jürgen Chopard, Dr. es Sciences (Economics) Director, Centre International de Glion, Glion, Switzerland, Dr. Chopard initially offers: “The recruitment of qualified personnel is extremely difficult in an industry with a poor image; where career paths are not well defined. The author discusses the employment of marketing management techniques to improve the positioning of hospitality education and create a more attractive perception of the hotel industry.” As outlined in the above paragraph, Dr. Chopard vectors-in on marketing strategies from two standpoints; the educational side with its focus on curriculum, and the larger, industry side with its emphasis on public perception and service. These are not necessarily, nor should they be viewed as disparate elements. “ Although some professionals may see schools of hospitality education catering to two markets, students on one hand and industry on the other, in fact, their needs should be viewed as the same and hence a single market,” Dr. Chopard says to bolster his assertion. “The marketing concept is a management orientation that holds that the key task of the organization is to determine the needs and wants of target markets and to adapt the organization to delivering the desired satisfactions more effectively and efficiently than its competitor,” the author confides, with an attribution. From these information/definition leanings, Dr. Chopard continues on a path that promotes the Centre International de Glion, Glion, Switzerland, which he is affiliated with. Why, because they endorse the same principles he is explaining to you. That’s not a bad thing. Essentially, what Dr. Chopard wants you to know is, education and business management are synonymous and therefore should share the same marketing designs and goals. “It is hard to believe that as critically important a sector as education does not use for its own management the techniques which it teaches and which have largely been proved in other fields,” the author provides as counterpoint. Since pedagogical needs so closely relate to the more pragmatic needs of the industry in general, these elements should seek to compliment and engage each other, in fact, collaboration is imperative, Dr. Chopard expresses a priori. “The cooperation of future employers is indispensable in the preparation of the product, so that it is capable of providing the expected services. The need for close relations between training establishments and the hotel and catering industry seems obvious,” Dr. Chopard says. The author reveals some flaws in hospitality marketing strategy, and then contrasts these against how a successful strategy could/should be implemented.

Constructing threat: How Americans identify economic competitors

China's emergence as an economic powerhouse has often been portrayed as threatening to America's economic strength and to its very identity as "the global hegemon." The media's alarmist response to an economic competitor is familiar to those who remember US-Japanese relations in the 1980s. In order to better understand the basis of American threat perception, this study explores the independent and interactive impact of three variables (perceptions of the Other's capabilities, perceptions of the Other as a threat versus as an opportunity, and perceptions of the Other's political culture) on attitudes toward two different economic competitors (Japan 1977-1995 and China 1985-2011). Utilizing four methods (historical process tracing, public polling data analysis, social scientific experimentation, and content analysis), this study demonstrates that increases in the Other's economic capabilities have a much smaller impact on attitudes than is commonly believed. It further shows that while perceptions of threat/opportunity played a significant role in shaping attitudinal response toward Japan, perceptions of political culture are the most important factor driving attitudes toward China today. This study contributes to a better understanding of how states react to threats and construct negative images of their economic rivals. It also helps to explain the current Sino-American relationship and enables better predictions as to its potential future course. Finally, these findings contribute to cultural explanations of the democratic peace phenomenon and provide a boundary condition (political culture) for the liberal proposition that opportunity ameliorates conflict in the economic realm.^

Net Bet Debt

The prospective high returns from gaming operations have introduced the Internet as a new competitor to the hotel and travel industry. With the dawn of the new millennium, am epidemic of gamblers has infected the virtual world and raised leagal problems yet to be solved.

An examination of the within -product category versus across -product category effects of partially comparative pricing

Partially comparative pricing involves a featured store providing price comparisons in reference to a competitor for some products (comparatively priced products) while omitting such comparisons and providing only its price for other products (non-comparatively priced products). Barone, Manning and Miniard (2004) found that while partially comparative pricing enhanced consumers' price perceptions of comparatively priced products at the featured retailer, it had the opposite effect for non-comparatively priced products (i.e., an inferiority effect). To the contrary, it is argued that a price comparison for one brand in a product category may enhance consumers' price perceptions of the remaining, non-comparatively priced brands within the same product category (i.e., a superiority effect). This research seeks to (a) examine the robustness of partially comparative pricing's effect in an across-product category context compared to a within-product category context and (b) extend the understanding of partially comparative pricing's within-product category effect on non-comparatively priced brands by examining potential moderators of this effect: brand diversity, brand typicality, and the relative expensiveness of the brand receiving the price comparison. The findings of four studies provide evidence to support the presence of a superiority effect in a within-product category context and suggests that the adverse effect of partially comparative pricing in an across-product category context may not be as robust as previously thought. Although the superiority effect was unaffected by brand diversity (i.e., whether the brands emanated from different manufacturers or from a single manufacturer), it was found to be moderated by the typicality of the brand receiving the price comparison as well as the comparison brand's relative expensiveness. Research participants formed more favorable relative price beliefs about the non-comparatively priced brand when the comparatively priced brand was perceived as a more typical member of the product category. Similarly, participants formed more favorable beliefs about the non-comparatively priced brand when the comparison price was assigned to the most expensive brand in the product category rather than the least expensive brand.

Relative roles of dispersal dynamics and competition in determining the isotopic niche breadth of a wetland fish

1. The niche variation hypothesis predicts that among-individual variation in niche use will increase in the presence of intraspecific competition and decrease in the presence of interspecific competition. We sought to determine whether the local isotopic niche breadth of fish inhabiting a wetland was best explained by competition for resources and the niche variation hypothesis, by dispersal of individuals from locations with different prey resources or by a combination of the two. We analysed stable isotopes of carbon and nitrogen as indices of feeding niche and compared metrics of within-site spread to characterise site-level isotopic niche breadth. We then evaluated the explanatory power of competing models of the direct and indirect effects of several environmental variables spanning gradients of disturbance, competition strength and food availability on among-individual variation of the eastern mosquitofish (Gambusia holbrooki). 2. The Dispersal model posits that only the direct effect of disturbance (i.e. changes in water level known to induce fish movement) influences among-individual variation in isotopic niche. The Partitioning model allows for only direct effects of local food availability on among-individual variation. The Combined model allows for both hypotheses by including the direct effects of disturbance and food availability. 3. A linear regression of the Combined model described more variance than models limited to the variables of either the Dispersal or Partitioning models. Of the independent variables considered, the food availability variable (per cent edible periphyton) explained the most variation in isotopic niche breadth, followed closely by the disturbance variable (days since last drying event). 4. Structural equation modelling provided further evidence that the Combined model was best supported by the data, with the Partitioning and the Dispersal models only modestly less informative. Again, the per cent edible periphyton was the variable with the largest direct effect on niche variability, with other food availability variables and the disturbance variable only slightly less important. Indirect effects of heterospecific and conspecific competitor densities were also important, through their effects on prey density. 5. Our results support the Combined hypotheses, although partitioning mechanisms appear to explain the most diet variation among individuals in the eastern mosquitofish. The results also support some predictions of the niche variation hypothesis, although both conspecific and interspecific competition appeared to increase isotopic niche breadth in contrast to predictions that interspecific competition would decrease it. We think this resulted from high diet overlap of co-occurring species, most of which consume similar macroinvertebrates.

Constructing Threat: How Americans Identify Economic Competitors

China’s emergence as an economic powerhouse has often been portrayed as threatening to America’s economic strength and to its very identity as “the global hegemon.” The media’s alarmist response to an economic competitor is familiar to those who remember US-Japanese relations in the 1980s. In order to better understand the basis of American threat perception, this study explores the independent and interactive impact of three variables (perceptions of the Other’s capabilities, perceptions of the Other as a threat versus as an opportunity, and perceptions of the Other’s political culture) on attitudes toward two different economic competitors (Japan 1977-1995 and China 1985-2011). Utilizing four methods (historical process tracing, public polling data analysis, social scientific experimentation, and content analysis), this study demonstrates that increases in the Other’s economic capabilities have a much smaller impact on attitudes than is commonly believed. It further shows that while perceptions of threat/opportunity played a significant role in shaping attitudinal response toward Japan, perceptions of political culture are the most important factor driving attitudes toward China today. This study contributes to a better understanding of how states react to threats and construct negative images of their economic rivals. It also helps to explain the current Sino-American relationship and enables better predictions as to its potential future course. Finally, these findings contribute to cultural explanations of the democratic peace phenomenon and provide a boundary condition (political culture) for the liberal proposition that opportunity ameliorates conflict in the economic realm.