Fever, firepower, and flood: the transformation of the Missouri River bottomlands in the Dakotas 1804-2005

This dissertation focuses on the indigneous geography of the Missouri River Valley of the Dakotas. Since Lewis and Clark\u27s expedition in 1804, this landscape has been transformed by two externally introduced components, reservations and reservoirs. To move the native tribes out of the way of an expanding American empire in the mid-19th century, the U.S. Government confined the tribes to territories, then to reservations, which grew smaller as each new wave of Euro-American immigration launched more land-taking by the federal government. To ensure military and political control over the tribes, the U.S. government supported the efforts of hide hunters to annihilate the immense bison herds and implemented a policy of forced assimilation. The 1887 General Allotment Act directly attacked Indian tribalism and freed up thousands of acres on the remaining reservations for white ownership. The most severe physical impacts to the bottomlands came in the mid-twentieth century with the construction of the Pick-Sloan reservoirs which inundated the fertile river bottomlands and destroyed what had been an oasis on the Plains for thousands of years. Human impacts to the Three Affiliated Tribes and to the Sioux have been severe and long-lasting; resulting in trans-generational trauma. Erosion created by the reservoirs has destroyed numerous archaeological sites and comprises a costly management problem for the Corps of Engineers. Indian cultural resurgence began with the Indian Reorganization Act of 1934 which finally put an end to the hated policies of allotment and assimilation and recognized native tribes as internal sovereign nations. With a renewed spirit of tribalism the Sious and the Three Affiliated Tribes have won important legal victories in federal courts to gain just compensation for the loss of the bottomlands. Prolonged drought and economic recession have caused a major demographic shift on the Plains (white depopulation) which has created many new frontier counties with fewer than six people per square mile. Native American have embraced a scaled-down version of the buffalo commons, which appears better suited to the semi-arid grassland ecosystem. A post-modern frontier landscape is emerging on the Northern Plains with many biogeographic features of the aboriginal landscape

Local seismicity of the Rainbow massif on the Mid‐Atlantic Ridge

Author Posting. © American Geophysical Union, 2018. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 123 (2018): 1615-1630, doi:10.1002/2017JB015288.The Rainbow massif, an oceanic core complex located in a nontransform discontinuity on the Mid‐Atlantic Ridge (36°N), is notable for hosting high‐temperature hydrothermal discharge through ultramafic rocks. Here we report results from a 9 month microearthquake survey conducted with a network of 13 ocean bottom seismometers deployed on and around the Rainbow massif as part of the MARINER experiment in 2013–2014. High rates (~300 per day) of low‐magnitude (average ML ~ 0.5) microearthquakes were detected beneath the massif. The hypocenters do not cluster along deeply penetrating fault surfaces and do not exhibit mainshock/aftershock sequences, supporting the hypothesis that the faulting associated with the exhumation of the massif is currently inactive. Instead, the hypocenters demarcate a diffuse zone of continuous, low‐magnitude deformation at relatively shallow (< ~3 km) depths beneath the massif, sandwiched in between the seafloor and seismic reflectors interpreted to be magmatic sills driving hydrothermal convection. Most of the seismicity is located in regions where seismic refraction data indicate serpentinized ultramafic host rock, and although the seismic network we deployed was not capable of constraining the focal mechanism of most events, our analysis suggests that serpentinization may play an important role in microearthquake generation at the Rainbow massif.NSF Grant Numbers: OCE‐0961680, OCE‐09611512018-07-2

Segment-scale variations in seafloor volcanic and tectonic processes from multibeam sonar imaging, Mid-Atlantic Ridge Rainbow region (35°45′–36°35′N)

Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry, Geophysics, Geosystems 17 (2016): 3560–3579, doi:10.1002/2016GC006433.Along-axis variations in melt supply and thermal structure can lead to significant variations in the mode of crustal accretion at mid-ocean ridges. We examine variations in seafloor volcanic and tectonic processes on the scale of individual ridge segments in a region of the slow spreading Mid-Atlantic Ridge (35°45′–36°35′N) centered on the Rainbow nontransform discontinuity (NTD). We use multibeam sonar backscatter amplitude data, taking advantage of multifold and multidirectional coverage from the MARINER geophysical study to create a gridded compilation of seafloor reflectivity, and interpret the sonar image within the context of other data to examine seafloor properties and identify volcanic flow fields and tectonic features. Along the spreading segments, differences in volcanic productivity, faulting, eruption style, and frequency correlate with inferred magma supply. Regions of low magma supply are associated with more widely spaced faults, and larger volcanic flow fields that are more easily identified in the backscatter image. Identified flow fields with the highest backscatter occur near the ends of ridge segments. Their relatively smooth topography contrasts with the more hummocky, cone-dominated terrain that dominates most of the neovolcanic zone. Patches of seafloor with high, moderately high, and low backscatter intensity across the Rainbow massif are spatially correlated with observations of basalt, gabbro and serpentinized peridotite, and sediment, respectively. Large detachment faults have repeatedly formed along the inside corners of the Rainbow NTD, producing a series of oceanic core complexes along the wake of the NTD. A new detachment fault is currently forming in the ridge segment just north of the now inactive Rainbow massif.National Science Foundation Grant Numbers: OCE-0961151, OCE-09616802017-03-0

Inactivation of cloned Na channels expressed in Xenopus oocytes

This study investigates the inactivation properties of Na channels expressed in Xenopus oocytes from two rat IIA Na channel cDNA clones differing by a single amino acid residue. Although the two cDNAs encode Na channels with substantially different activation properties (Auld, V. J., A. L. Goldin, D. S. Krafte, J. Marshall, J. M. Dunn, W. A. Catterall, H. A. Lester, N. Davidson, and R. J. Dunn. 1988. Neuron. 1:449-461), their inactivation properties resemble each other strongly but differ markedly from channels induced by poly(A+) rat brain RNA. Rat IIA currents inactivate more slowly, recover from inactivation more slowly, and display a steady-state voltage dependence that is shifted to more positive potentials. The macroscopic inactivation process for poly(A+) Na channels is defined by a single exponential time course; that for rat IIA channels displays two exponential components. At the single-channel level these differences in inactivation occur because rat IIA channels reopen several times during a depolarizing pulse; poly(A+) channels do not. Repetitive stimulation (greater than 1 Hz) produces a marked decrement in the rat IIA peak current and changes the waveform of the currents. When low molecular weight RNA is coinjected with rat IIA RNA, these inactivation properties are restored to those that characterize poly(A+) channels. Slow inactivation is similar for rat IIA and poly(A+) channels, however. The data suggest that activation and inactivation involve at least partially distinct regions of the channel protein

Functional Analysis of Subunit e of the F\u3csub\u3e1\u3c/sub\u3eF\u3csub\u3eo\u3c/sub\u3e-ATP Synthase of the Yeast \u3cem\u3eSaccharomyces cerevisiae\u3c/em\u3e: Importance of the N-Terminal Membrane Anchor Region

Mitochondrial F1Fo-ATP synthase complexes do not exist as physically independent entities but rather form dimeric and possibly oligomeric complexes in the inner mitochondrial membrane. Stable dimerization of two F1Fo-monomeric complexes involves the physical association of two membrane-embedded Fo-sectors. Previously, formation of the ATP synthase dimeric-oligomeric network was demonstrated to play a critical role in modulating the morphology of the mitochondrial inner membrane. In Saccharomyces cerevisiae, subunit e (Su e) of the Fo-sector plays a central role in supporting ATP synthase dimerization. The Su e protein is anchored to the inner membrane via a hydrophobic region located at its N-terminal end. The hydrophilic C-terminal region of Su e resides in the intermembrane space and contains a conserved coiled-coil motif. In the present study, we focused on characterizing the importance of these regions for the function of Su e. We created a number of C-terminal-truncated derivatives of the Su e protein and expressed them in the Su e null yeast mutant. Mitochondria were isolated from the resulting transformant strains, and a number of functions of Su e were analyzed. Our results indicate that the N-terminal hydrophobic region plays important roles in the Su e-dependent processes of mitochondrial DNA maintenance, modulation of mitochondrial morphology, and stabilization of the dimer-specific Fo subunits, subunits g and k. Furthermore, we show that the C-terminal coiled-coil region of Su e functions to stabilize the dimeric form of detergent-solubilized ATP synthase complexes. Finally, we propose a model to explain how Su e supports the assembly of the ATP synthase dimers-oligomers in the mitochondrial membrane

Three-dimensional seismic structure of the Mid-Atlantic Ridge (35°N) : evidence for focused melt supply and lower crustal dike injection

Author Posting. © American Geophysical Union, 2005. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 110 (2005): B09101, doi:10.1029/2004JB003473.We gathered seismic refraction and wide-angle reflection data from several active source experiments that occurred along the Mid-Atlantic Ridge near 35°N and constructed three-dimensional anisotropic tomographic images of the crust and upper mantle velocity structure and crustal thickness. The tomographic images reveal anomalously thick crust (8–9 km) and a low-velocity “bull's-eye”, from 4 to 10 km depth, beneath the center of the ridge segment. The velocity anomaly is indicative of high temperatures and a small amount of melt (up to 5%) and likely represents the current magma plumbing system for melts ascending from the mantle. In addition, at the segment center, seismic anisotropy in the lower crust indicates that the crust is composed of partially molten dikes that are surrounded by regions of hot rock with little or no melt fraction. Our results indicate that mantle melts are focused at mantle depths to the segment center and that melt is delivered to the crust via dikes in the lower crust. Our results also indicate that the segment ends are colder, receive a reduced magma supply, and undergo significantly greater tectonic stretching than the segment center.This research was supported by U.S. National Science Foundation grants OCE-0203228 and OCE-0136793; support for V. Lekic was provided by the IRIS undergraduate internship program

Three-dimensional seismic structure of the Mid-Atlantic Ridge : an investigation of tectonic, magmatic, and hydrothermal processes in the Rainbow Area

Author Posting. © American Geophysical Union, 2017. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 122 (2017): 9580–9602, doi:10.1002/2017JB015051.To test models of tectonic, magmatic, and hydrothermal processes along slow-spreading mid-ocean ridges, we analyzed seismic refraction data from the Mid-Atlantic Ridge INtegrated Experiments at Rainbow (MARINER) seismic and geophysical mapping experiment. Centered at the Rainbow area of the Mid-Atlantic Ridge (36°14'N), this study examines a section of ridge with volcanically active segments and a relatively amagmatic ridge offset that hosts the ultramafic Rainbow massif and its high-temperature hydrothermal vent field. Tomographic images of the crust and upper mantle show segment-scale variations in crustal structure, thickness, and the crust-mantle transition, which forms a vertical gradient rather than a sharp boundary. There is little definitive evidence for large regions of sustained high temperatures and melt in the lower crust or upper mantle along the ridge axes, suggesting that melts rising from the mantle intrude as small intermittent magma bodies at crustal and subcrustal levels. The images reveal large rotated crustal blocks, which extend to mantle depths in some places, corresponding to off-axis normal fault locations. Low velocities cap the Rainbow massif, suggesting an extensive near-surface alteration zone due to low-temperature fluid-rock reactions. Within the interior of the massif, seismic images suggest a mixture of peridotite and gabbroic intrusions, with little serpentinization. Here diffuse microearthquake activity indicates a brittle deformation regime supporting a broad network of cracks. Beneath the Rainbow hydrothermal vent field, fluid circulation is largely driven by the heat of small cooling melt bodies intruded into the base of the massif and channeled by the crack network and shallow faults.NSF Grant Numbers: OCE-0961151, OCE-09616802018-06-2

Science on a Shoestring: Building Nursing Knowledge With Limited Funding

Building the science for nursing practice has never been more important. However, shrunken federal and state research budgets mean that investigators must find alternative sources of financial support and develop projects that are less costly to carry out. New investigators often build beginning programs of research with limited funding. This article provides an overview of some cost-effective research approaches and gives suggestions for finding other sources of funding. Examples of more cost-effective research approaches include adding complementary questions to existing funded research projects; conducting primary analysis of electronic patient records and social media content; conducting secondary analysis of data from completed studies; reviewing and synthesizing previously completed research; implementing community-based participatory research; participating in collaborative research efforts such as inter-campus team research, practice-based research networks (PBRNs), and involving undergraduate and doctoral students in research efforts. Instead of relying on funding from the National Institutes of Health (NIH) and other government agencies, nurse researchers may be able to find support for research from local sources such as businesses, organizations, or clinical agencies. Investigators will increasingly have to rely on these and other creative approaches to fund and implement their research programs if granting agency budgets do not significantly expand