2 resultados para Alice in Wonderland
em Digital Commons - Michigan Tech
Resumo:
Eutrophication is a persistent problem in many fresh water lakes. Delay in lake recovery following reductions in external loading of phosphorus, the limiting nutrient in fresh water ecosystems, is often observed. Models have been created to assist with lake remediation efforts, however, the application of management tools to sediment diagenesis is often neglected due to conceptual and mathematical complexity. SED2K (Chapra et al. 2012) is proposed as a "middle way", offering engineering rigor while being accessible to users. An objective of this research is to further support the development and application SED2K for sediment phosphorus diagenesis and release to the water column of Onondaga Lake. Application of SED2K has been made to eutrophic Lake Alice in Minnesota. The more homogenous sediment characteristics of Lake Alice, compared with the industrially polluted sediment layers of Onondaga Lake, allowed for an invariant rate coefficient to be applied to describe first order decay kinetics of phosphorus. When a similar approach was attempted on Onondaga Lake an invariant rate coefficient failed to simulate the sediment phosphorus profile. Therefore, labile P was accounted for by progressive preservation after burial and a rate coefficient which gradual decreased with depth was applied. In this study, profile sediment samples were chemically extracted into five operationally-defined fractions: CaCO3-P, Fe/Al-P, Biogenic-P, Ca Mineral-P and Residual-P. Chemical fractionation data, from this study, showed that preservation is not the only mechanism by which phosphorus may be maintained in a non-reactive state in the profile. Sorption has been shown to contribute substantially to P burial within the profile. A new kinetic approach involving partitioning of P into process based fractions is applied here. Results from this approach indicate that labile P (Ca Mineral and Organic P) is contributing to internal P loading to Onondaga Lake, through diagenesis and diffusion to the water column, while the sorbed P fraction (Fe/Al-P and CaCO3-P) is remaining consistent. Sediment profile concentrations of labile and total phosphorus at time of deposition were also modeled and compared with current labile and total phosphorus, to quantify the extent to which remaining phosphorus which will continue to contribute to internal P loading and influence the trophic status of Onondaga Lake. Results presented here also allowed for estimation of the depth of the active sediment layer and the attendant response time as well as the sediment burden of labile P and associated efflux.
Resumo:
The 1913-14 Michigan copper strike is unlike many American labor actions of the period in that it did not include red flags or socialist anthems. Many of the most familiar photographs of the strike involve American flags, not red ones. Similarly, the songs mentioned in journalistic accounts of the strikers are American Civil War songs, not popular labor songs of the period. The few newly-written songs about the strike, published in the local newspapers, seem cautiously polite and espouse values such as patriotism, liberty and human rights. During a time when sections of the "friendly" press were concerned with labor presenting the correct image and avoiding unfavorable associations, the Copper Country strikers, and the W.F.M., seem to have been attempting to create a fresh narrative regarding what this strike was (and what it was not). This paper will consider elements of the Copper Country strike in the light of media coverage, prior to July 1913, of several American labor topics that might have influenced the way the strike was presented. Particular attention will be given to photographs, songs, and accounts from the 1912 Lawrence textile strike, as well as contemporaneous critiques of labor song lyrics. Most of this commentary will be drawn from the labor and socialist press, demonstrating that the 1913-14 Michigan copper strike occurred during a period in which the labor movement was struggling to craft and image that would display it as it wished to be seen. This paper has not yet been submitted.