Aquatic Effects of a Localized Oil Spill on Lake Conway, AR and Its Tributaries

Oil spills, no matter where they occur, elicit environmental concern and avoiding these disasters should be a priority. Old pipelines that are not regularly maintained and carry large amounts of crude oil long distances are of particular concern. One such pipeline is the 65 year-old Pegasus pipeline owned by ExxonMobil. On March 29, 2013, 795,000 L of Wabasca Heavy Canadian crude oil spilled into a neighborhood of Mayflower, Arkansas, when the Pegasus pipeline ruptured. This spill led to the evacuation of many homes in the surrounding neighborhood. Drainage ditches in the affected neighborhood drained oil into a nearby cove of Lake Conway. This lake is popular for recreational fishing, thus concerns were raised not only about the potential effects of the oil spill on area residents, but also the lake and its biological communities. Ultimately, this project assessed the effect of the oil spill in water and sediment samples on freshwater test organisms. Samples were collected at 6 sites in the affected neighborhood and in Lake Conway. Chronic Whole Effluent Toxicity (WET) tests were performed on water samples using Pimephales promelas and Ceriodaphnia dubia. Acute sediment toxicity tests were performed using Chironomus dilutus. These tests measured sub-lethal toxicity in at least one of the sampled sites, indicating that further investigation of environmental after-effects is warranted

Characterization of temporal and spatial variation in subwatersheds of the Strawberry River, AR, prior to implementation of agricultural best management practices

Benthic macroinvertebrate (BMI) assessments indicate alterations in physical and/or chemical factors making them valuable tools when attempting to assess agricultural best management practices (BMPs). The purpose of this study was to obtain pre-BMP land cover and macroinvertebrate community data in order to characterize temporal and spatial variation in three catchments: Little Strawberry (LS), Greasy Creek (GC), and Sandy Creek (SC) of the Strawberry River Watershed, located in north central Arkansas, in order to establish baseline conditions. BMIs were collected for the three subwatersheds in 1995, 1999, 2002, 2003 and 2009. Taxa richness, Hilsenhoff Biotic Index (HBI) and Ephemeroptera, Plecoptera and Trichoptera (EPT) score, % dominant taxa, and % Diptera were used as indicators of water quality and habitat changes. All subwatersheds experienced decreased forest land cover indicating land use transition. All resulting BMI measures indicate overall stable habitat and water conditions in the LS subwatershed. Results for GC subwatershed vary with taxa richness, EPT and HBI indicating a stable habitat while increasing % dominant taxa and Diptera indicate a decreasing trend in overall habitat quality. All BMI measures in the SC subwatershed indicate decreasing trend in habitat quality. The most sensitive measure to temporal changes was % Diptera. Trends were not consistent among subwatersheds indicating the importance of continued data collection to establish baseline data and truly monitor changes in aquatic systems over time

Natural Nutrient Sources in the Cache River Watershed, Arkansas

The growth of the hypoxic ‘dead zone’ in the Gulf of Mexico in recent years has placed increased focus on potential sources of nutrient pollution, with most of the focus being placed on watersheds where practices, including fertilizer application and land alterations combine to increase non-point source runoff. In this study, nutrient concentrations in surface waters of altered and unaltered areas of the Cache River Watershed, Arkansas, were compared to determine if agricultural land usage was responsible for the majority of nutrient inputs. Results suggest that for dissolved nitrites and orthophosphates, agricultural (altered) sites contribute significantly more than relatively unaltered sites but that for dissolved nitrates, unaltered sites have a large contribution to overall nitrate concentrations, particularly in late summer and fall months

Establishing Baseline Nutrient and Sediment Input in the Lower Cache River Watershed, AR

Contaminants in waterways continue to be a problem especially in watersheds dominated by land use changes such as agriculture. Clearing the land for agricultural use is needed to support the population; however, agricultural contaminants are cited as contributing the greatest input of suspended solids and nutrients to waterways. Quantifying various contaminants in surface water is useful in determining their origin, thus aiding in their mitigation. This study, focused on the Cache River Watershed, reports pH, dissolved oxygen (DO), conductivity, turbidity, total suspended solids (TSS), NO3 - , NO2 - , and PO4 3- in the lower sub watersheds. It was determined that in the Cache River, at these particular sites, TSS, NO3 - , NO2 - , and PO4 3- concentrations differ due to varying sources of input and land use

Autonomic nervous system involvement in the giant axonal neuropathy (GAN) KO mouse: implications for human disease

Giant axonal neuropathy (GAN) is an inherited severe sensorimotor neuropathy. The aim of this research was to investigate the neuropathologic features and clinical autonomic nervous system (ANS) phenotype in two GAN knockout (KO) mouse models. Little is known about ANS involvement in GAN in humans, but autonomic signs and symptoms are commonly reported in early childhood

Nullspaces and frames

In this paper we give new characterizations of Riesz and conditional Riesz frames in terms of the properties of the nullspace of their synthesis operators. On the other hand, we also study the oblique dual frames whose coefficients in the reconstruction formula minimize different weighted norms.Comment: 16 page

Ferromagnetism of 3^3He Films in the Low Field Limit

We provide evidence for a finite temperature ferromagnetic transition in 2-dimensions as $H \to 0$ in thin films of $^3$He on graphite, a model system for the study of two-dimensional magnetism. We perform pulsed and CW NMR experiments at fields of 0.03 - 0.48 mT on $^3$He at areal densities of 20.5 - 24.2 atoms/nm$^2$. At these densities, the second layer of $^3$He has a strongly ferromagnetic tendency. With decreasing temperature, we find a rapid onset of magnetization that becomes independent of the applied field at temperatures in the vicinity of 1 mK. Both the dipolar field and the NMR linewidth grow rapidly as well, which is consistent with a large (order unity) polarization of the $^3$He spins.Comment: 4 figure

Book Reviews

Book reviews of: William F. Winter and the New Mississippi: A Biography. By Charles C. Bolton Jackson: University Press of Mississippi, 2013. Pp. vii, 368. Illustrations, map, acknowledgements, notes, index. $35.00 cloth. ISBN: 9781617037870. Born of Conviction: White Methodists and Mississippi’s Closed Society. By Joseph T. Reiff. (New York: Oxford University Press, 2016. Acknowledgements, illustrations, map, notes, index. Pp. xxi, 384.$35 Hardcover. ISBN: 9780190246815). In Katrina’s Wake: The U.S. Coast Guard and the Gulf Coast Hurricanes of 2005. By Donald L. Canney. (Gainesville: University Press of Florida, 2010. Foreword, notes, index. Pp. xv, 228. $27.50 cloth.) Slavery, Race and Conquest in the Tropic: Lincoln, Douglas and the Future of America. By Robert E. May. (New York: Cambridge University Press, 2013. Acknowledgements, illustrations, maps, notes, index. Pp. xi, 296.$80 cloth, $26.99 paper,$22 e-book. ISBN: 9780521132527.) Rivers of Sand: Creek Indian Emigration, Relocation, and Ethnic Cleansing in the American South. By Christopher D. Haveman. (Nebraska: University of Nebraska Press, 2016. Illustrations, preface, acknowledgments, notes on terminology, index. Pp. ix, 414. Trouble in Goshen: Plain Folk, Roosevelt, Jesus, and Marx in the Great Depression. By Fred C. Smith (Jackson: University Press of Mississippi, 2014. Acknowledgements, illustrations, map notes, index. Pp. xi, 214. $60.00 cloth. ISBN: 9781617039560.) Builders of a New South: Merchants, Capital, and the Remaking of Natchez, 1865-1914. By Aaron D. Anderson (Jackson: University Press of Mississippi, 2013. Acknowledgments, illustrations, photographs, notes, graphics, index. Pp. 279.$40 cloth. ISBN: 978-1- 61703-667-5.) Adventurism and Empire: The Struggle for Mastery in the Louisiana- Florida Borderlands 1762-1803. By David Narrett. (Chapel Hill: The University of North Carolina Press, 2015. Acknowledgements, illustrations, notes, index. Pp. xi, 365. $45 cloth,$44.99 e-book. ISBN: 978-1-4696-1833-3.) Empty Sleeves: Amputation in the Civil War South. By Brian Craig Miller. (Athens: University of Georgia Press, 2015. Illustrations, acknowledgments, appendix, notes, index. Pp. xvi, 257. $79.95 cloth,$29.95 paper. ISBN: 0820343327.) Signposts: New Directions in Southern Legal History. By Sally E. Hadden and Patricia Hagler Minter, eds. (Athens and London: The University of Georgia Press, 2013. Acknowledgements, illustrations, index. Pp. xi, 480. $69.95 cloth,$26.95 paper, $26.95 ebook. ISBN: 978-0-8203-4499-7.) The Color of Christ: The Son of God and the Saga of Race in America. By Edward J. Blum and Paul Harvey. (Chapel Hill: University of North Carolina Press, 2012. Pp. 325.$32.50 Cloth. ISBN: 9780807835722.

Advancing the pathologic phenotype of giant axonal neuropathy: early involvement of the ocular lens

Abstract Giant axonal neuropathy (GAN; ORPHA: 643; OMIM# 256850) is a rare, hereditary, pediatric neurodegenerative disorder associated with intracellular accumulations of intermediate filaments (IFs). GAN knockout (KO) mouse models mirror the IF dysregulation and widespread nervous system pathology seen in human GAN. Validation of therapeutic efficacy and viral vector delivery systems with these GAN KO models has provided the springboard for the development of a viral vector being delivered intrathecally in an ongoing Phase I gene therapy clinical trial for the treatment of children with GAN ( https://clinicaltrials.gov/ct2/show/NCT02362438 ). During the course of a comprehensive pathologic characterization of the GAN KO mouse, we discovered the very early and unexpected involvement of the ocular lens. Light microscopy revealed the presence of intracytoplasmic inclusion bodies within lens epithelial cells. The inclusion bodies showed strong immunohistochemical positivity for glial fibrillary acidic protein (GFAP). We confirmed that intracytoplasmic inclusion bodies are also present within lens epithelial cells in human GAN. These IF inclusion bodies in lens epithelial cells are unique to GAN. Similar IF inclusion bodies in lens epithelial cells have not been reported previously in experimental animal models or human diseases. Since current paradigms in drug discovery and drug repurposing for IF-associated disorders are often hindered by lack of validated targets, our findings suggest that lens epithelial cells in the GAN KO mouse may provide a potential target, in vivo and in vitro, for evaluating drug efficacy and alternative therapeutic approaches in promoting the clearance of IF inclusions in GAN and other diseases characterized by intracellular IF accumulations

The adaptive capacity of maize-based conservation agriculture systems to climate stress in tropical and subtropical environments: A meta-regression of yields

Conservation agriculture is widely promoted across sub-Saharan Africa as a sustainable farming practice that enhances adaptive capacity to climate change. The interactions between climate stress, management, and soil are critical to understanding the adaptive capacity of conservation agriculture. Yet conservation agriculture syntheses to date have largely neglected climate, especially the effects of extreme heat. For the sub-tropics and tropics, we use meta-regression, in combination with global soil and climate datasets, to test four hypotheses: (1) that relative yield performance of conservation agriculture improves with increasing drought and temperature stress; (2) that the effects of moisture and temperature stress exposure interact; (3) that the effects of moisture and temperature stress are modified by soil texture; and (4) that crop diversification, fertilizer application rate, or the time since no-till implementation will enhance conservation agriculture performance under climate stress. Our results support the hypothesis that the relative maize yield performance of conservation agriculture improves with increasing drought severity or exposure to high temperatures. Further, there is an interaction of moisture and heat stress on conservation agriculture performance and their combined effect is both non-additive and modified by soil clay content, supporting our second and third hypotheses. Finally, we found only limited support for our fourth hypothesis as (1) increasing nitrogen application rates did not improve the relative performance of conservation agriculture under high heat stress; (2) crop diversification did not notably improve conservation agriculture performance, but did increase its stability with heat stress; and (3) a statistically robust effect of the time since no-till implementation was not evident. Our meta-regression supports the narrative that conservation agriculture enhances the adaptive capacity of maize production in sub-Saharan Africa under drought and/or heat stress. However, in very wet seasons and on clay-rich soils, conservation agriculture yields less compared to conventional practices