Postscripts

Walt Whitman’s meditation on time is the undercurrent running through Postscripts, a series of reflections on finding one’s place in the endless chain of time. In linked essays, Robert Root ranges across American terrains and landscapes including locales as varied as Walden Pond and Mesa Verde, the mountains of Montana and the coastline of Maine, Great Lakes shorelines and Manhattan on the first day of the war with Iraq. Rich in “all that retrospection,” Postscripts chronicles moments of intimacy and arrival in the natural world while also charting intersections of natural, cultural, and personal history. Whether revisiting the first European settlement in Nova Scotia or seeking out the sites of E. B. White’s life and literature, exploring the only old-growth forest in lower Michigan or shifting perceptions at the birth of a granddaughter, Root offers readers a new perspective on the relationship between time and place, time and timelessness, history and personal history. If the past is prologue, his book suggests, the present is postscript

The Experimental Art

Nonfiction is an experimental art, as contemporary examples make clear, and writing teachers need to show students both how meaning arises from writers\u27 experiments with material and also how form from writers\u27 experiments at representing meaning

An Insulin-Like Modular Basis for the Evolution of Glucose Transporters (GLUT) with Implications for Diabetes

Glucose transporters (GLUT) are twelve-transmembrane spanning proteins that contain two pores capable of transporting glucose and dehydroascorbate in and out of cells. The mechanism by which transport is effected is unknown. An evolutionarily-based hypothesis for the mechanism of glucose transport is presented here based on reports that insulin has multiple binding sites for glucose. It is proposed that insulin-like peptides were incorporated as modular elements into transmembrane proteins during evolution, resulting in glucose transporting capacity. Homology searching reveals that all GLUT contain multiple copies of insulin-like regions. These regions map onto a model of GLUT in positions that define the glucose transport cores. This observation provides a mechanism for glucose transport involving the diffusion of glucose from one insulin-like glucose-binding region to another. It also suggests a mechanism by which glucose disregulation may occur in both type 1 and type 2 diabetes: insulin rapidly self-glycates under hyperglycemic conditions. Insulin-like regions of GLUT may also self-glycate rapidly, thereby interfering with transport of glucose into cells and disabling GLUT sensing of blood glucose levels. All aspects of the hypothesis are experimentally testable

DECISIONS IN THE DARK: A FRAMEWORK FOR DECISION-MAKING IN UNFAMILIAR SITUATIONS

This thesis seeks to understand an appropriate decision-making framework for the fire service to use in unfamiliar situations. Firefighters and emergency responders rely on pattern recognition when they are presented with familiar situations; however, relying on such intuition can result in costly time delays. A case study method was used to evaluate decision-making during disasters in the fire service and the mining industry. The fire service cases include the 1949 Mann Gulch Fire and the fire service response to the 9/11 attack on the World Trade Center. The mining case studies, both of which occurred in 2010, include the Deepwater Horizon oil spill and the Chilean mine collapse. The fire service cases were assessed to determine which decision-making tools were utilized and what additional factors influenced positive and negative outcomes throughout the events. The mining cases were evaluated to understand organizational structures and response systems. This thesis recommends that fire service leaders utilize expanded interdisciplinary teams to creatively seek alternative solutions when addressing unfamiliar problems. Using such teams will require leaders to expand response frameworks and alter familiar patterns of response to include outside agencies and nontraditional emergency responders. Finally, leaders should deliberately encourage open communication about successes and failures to encourage collaboration and innovation throughout the response.Civilian, Portland Fire and RescueApproved for public release. Distribution is unlimited

A Gel Probe Equilibrium Sampler for Measuring Arsenic Porewater Profiles and Sorption Gradients in Sediments: I. Laboratory Development

A gel probe equilibrium sampler has been developed to study arsenic (As) geochemistry and sorption behavior in sediment porewater. The gels consist of a hydrated polyacrylamide polymer, which has a 92% water content. Two types of gels were used in this study. Undoped (clear) gels were used to measure concentrations of As and other elements in sediment porewater. The polyacrylamide gel was also doped with hydrous ferric oxide (HFO), an amorphous iron (Fe) oxyhydroxide. When deployed in the field, HFO-doped gels introduce a fresh sorbent into the subsurface thus allowing assessment of in situ sorption. In this study, clear and HFO-doped gels were tested under laboratory conditions to constrain the gel behavior prior to field deployment. Both types of gels were allowed to equilibrate with solutions of varying composition and re-equilibrated in acid for analysis. Clear gels accurately measured solution concentrations (±1%), and As was completely recovered from HFO-doped gels (±4%). Arsenic speciation was determined in clear gels through chromatographic separation of the re-equilibrated solution. For comparison to speciation in solution, mixtures of As(III) and As(V) adsorbed on HFO embedded in gel were measured in situ using X-ray absorption spectroscopy (XAS). Sorption densities for As(III) and As(V) on HFO embedded in gel were obtained from sorption isotherms at pH 7.1. When As and phosphate were simultaneously equilibrated (in up to 50-fold excess of As) with HFO-doped gels, phosphate inhibited As sorption by up to 85% and had a stronger inhibitory effect on As(V) than As(III). Natural organic matter (>200 ppm) decreased As adsorption by up to 50%, and had similar effects on As(V) and As(III). The laboratory results provide a basis for interpreting results obtained by deploying the gel probe in the field and elucidating the mechanisms controlling As partitioning between solid and dissolved phases in the environment

The Eukaryotic Cell Originated in the Integration and Redistribution of Hyperstructures from Communities of Prokaryotic Cells Based on Molecular Complementarity

In the “ecosystems-first” approach to the origins of life, networks of non-covalent assemblies of molecules (composomes), rather than individual protocells, evolved under the constraints of molecular complementarity. Composomes evolved into the hyperstructures of modern bacteria. We extend the ecosystems-first approach to explain the origin of eukaryotic cells through the integration of mixed populations of bacteria. We suggest that mutualism and symbiosis resulted in cellular mergers entailing the loss of redundant hyperstructures, the uncoupling of transcription and translation, and the emergence of introns and multiple chromosomes. Molecular complementarity also facilitated integration of bacterial hyperstructures to perform cytoskeletal and movement functions