706 research outputs found

    The black experience in selected Nebraska counties, 1854-1920

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    This work is a history of the black experience in the fifteen most densely black populated counties in Nebraska, excluding Douglas, from 1854 through 1920. Beginning with the formation of Nebraska Territory in 1854, the thesis studies the population, employment, and social status of blacks living in Nebraska throughout the frontier and postfrontier eras. Slavery and suffrage are critically examined throughout the territorial period. Following statehood, the impact of black migration into the state is studied, especially during the years 1879 and 1880. Massive migration of southern blacks into northern states occurred during those years, a result of the termination of military reconstruction in the South. The reactions of some Nebraska communities are analyzed as blacks began to migrate to their localities in the late 1870s. During the 1880s Nebraskans witnessed a steady but minimal flow of blacks into the state, as they settled primarily in towns along railroads, on farms, and at military forts. The prosperity in Nebraska at that time allowed for a lessening of some social and political restraints upon blacks. However, the depression of the early 1890s curbed those restraints as blacks were suffering severely from the worsening economic conditions. During that time blacks faced increased racism and declining social status, forcing some of them to leave the state. It was not until after the turn of the century that blacks again began to return to the state, searching to improve their economic condition. After 1900, blacks throughout Nebraska increasingly found employment as hotel porters, restaurant cooks and waiters, and general laborers. The black population within the state continued to increase gradually as larger percentages of blacks settled in Omaha and Lincoln, a trend similar to that of other Nebraskans who were moving away from the state\u27s rural areas. Among other things, this thesis provides a comprehensive bibliography for students of black history in Nebraska. In short, this thesis concludes that as blacks ventured to Nebraska from various locations and often of similar economic circumstances they usually found employment in occupations deemed suitable for their race. Black settlement often stimulated anxiety and prejudice among many of Nebraska\u27s citizens. Although most Nebraskans during the period were never engaged in direct overt acts of discrimination, prejudices among some Nebraskans at times manifested violent acts by the white majority against the much smaller black population. As a result, blacks in Nebraska often faced social and political prejudices similar to those simultaneously experienced by other members of their race throughout the United States

    A Combined XRD/XRF Instrument for Lunar Resource Assessment

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    Robotic surface missions to the Moon should be capable of measuring mineral as well as chemical abundances in regolith samples. Although much is already known about the lunar regolith, our data are far from comprehensive. Most of the regolith samples returned to Earth for analysis had lost the upper surface, or it was intermixed with deeper regolith. This upper surface is the part of the regolith most recently exposed to the solar wind; as such it will be important to resource assessment. In addition, it may be far easier to mine and process the uppermost few centimeters of regolith over a broad area than to engage in deep excavation of a smaller area. The most direct means of analyzing the regolith surface will be by studies in situ. In addition, the analysis of the impact-origin regolith surfaces, the Fe-rich glasses of mare pyroclastic deposits, are of resource interest, but are inadequately known; none of the extensive surface-exposed pyroclastic deposits of the Moon have been systematically sampled, although we know something about such deposits from the Apollo 17 site. Because of the potential importance of pyroclastic deposits, methods to quantify glass as well as mineral abundances will be important to resource evaluation. Combined x ray diffraction (XRD) and x ray fluorescence (XRF) analysis will address many resource characterization problems on the Moon. XRF methods are valuable for obtaining full major-element abundances with high precision. Such data, collected in parallel with quantitative mineralogy, permit unambiguous determination of both mineral and chemical abundances where concentrations are high enough to be of resource grade. Collection of both XRD and XRF data from a single sample provides simultaneous chemical and mineralogic information. These data can be used to correlate quantitative chemistry and mineralogy as a set of simultaneous linear equations, the solution of which can lead to full characterization of the sample. The use of Rietveld methods for XRD data analysis can provide a powerful tool for quantitative mineralogy and for obtaining crystallographic data on complex minerals

    Mineralogy and chemistry of altered Icelandic basalts: Application to clay mineral detection and understanding aqueous environments on Mars

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    We used a suite of techniques, including those emulating compositional data sets obtained from Mars orbit and obtainable at the Mars surface, to examine aqueous alteration of basaltic rocks from Iceland as a mineralogic and geochemical analog for Noachian environments on Mars. A sample suite was collected for laboratory measurement of (1) whole-rock visible/near-infrared (VNIR) reflectance and thermal infrared (TIR) emission spectra; (2) VNIR and TIR reflectance spectra of particle-size separates derived from the bulk rock and from materials extracted from fractures/vesicles; (3) X-ray diffraction (XRD) patterns for determination of quantitative modal mineralogy; (4) major element chemistry using flux fusion of whole-rock powders; and (5) electron microprobe analyses of minerals in thin sections. Conclusions about aqueous alteration can be influenced by technique. For these basalts, whole-rock chemical data showed scant evidence for chemical fractionation, but TIR, VNIR, and XRD measurements identified distinctive assemblages of hydrous silicate minerals, differing by sample. XRD provided the most complete and accurate quantitative determination of sample mineralogy. However, VNIR spectroscopy was the technique most useful for determining composition of low-abundance smectite clays, and TIR spectroscopy was the most useful for recognizing hydrated silicates in thin surface coatings. High spatial resolution mineralogical and chemical data sets were useful for understanding the texture and distribution of alteration products and variations in fluid chemistry. No single approach provides a complete assessment of the environment of alteration, demonstrating the importance of employing multiple, synergistic mineralogical and geochemical techniques and instruments in exploration of rock strata from aqueous paleoenvironments on Mars

    Koinonia

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    In This IssueThe Outward Bound Temporary Community : A Practical Framework for Understanding Residence Life, Eric Spiecker Community Service Learning and Christian Higher Education, Lynne Sparks Diversity Education: Helping Students Find a Common Ground, Brent D. Ellis Student Bashing: An Unseemly Academic Tradition, George D. Kuh In The FieldGender Dynamics in the Classroom at an Evangelical Christian Liberal Arts College, Edee Schulze Around CampusFrom Service to Learning, Greg Bish CoCCA Hot Tip: Celebrating Diversity Regular FeaturesPresident\u27s Corner Editor\u27s Disk Annual Conference: New Professionals Retreat Book Review: More Light Less Heat: How Dialogue Can Transform Christian Conflicts Into Growth Perspective: To Do, To Have, or To Be? That is the Questionhttps://pillars.taylor.edu/acsd_koinonia/1021/thumbnail.jp

    Comprehensive protein interactome analysis of a key RNA helicase: detection of novel stress granule proteins

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    DDX6 (p54/RCK) is a human RNA helicase with central roles in mRNA decay and translation repression. To help our understanding of how DDX6 performs these multiple functions, we conducted the first unbiased, large-scale study to map the DDX6-centric protein-protein interactome using immunoprecipitation and mass spectrometry. Using DDX6 as bait, we identify a high-confidence and high-quality set of protein interaction partners which are enriched for functions in RNA metabolism and ribosomal proteins. The screen is highly specific, maximizing the number of true positives, as demonstrated by the validation of 81% (47/58) of the RNA-independent interactors through known functions and interactions. Importantly, we minimize the number of indirect interaction partners through use of a nuclease-based digestion to eliminate RNA. We describe eleven new interactors, including proteins involved in splicing which is an as-yet unknown role for DDX6. We validated and characterized in more detail the interaction of DDX6 with Nuclear fragile X mental retardation-interacting protein 2 (NUFIP2) and with two previously uncharacterized proteins, FAM195A and FAM195B (here referred to as granulin-1 and granulin-2, or GRAN1 and GRAN2). We show that NUFIP2, GRAN1, and GRAN2 are not P-body components, but re-localize to stress granules upon exposure to stress, suggesting a function in translation repression in the cellular stress response. Using a complementary analysis that resolved DDX6's multiple complex memberships, we further validated these interaction partners and the presence of splicing factors. As DDX6 also interacts with the E3 SUMO ligase TIF1β, we tested for and observed a significant enrichment of sumoylation amongst DDX6's interaction partners. Our results represent the most comprehensive screen for direct interaction partners of a key regulator of RNA life cycle and localization, highlighting new stress granule components and possible DDX6 functions-many of which are likely conserved across eukaryotes

    A Terrestrial Analogue from Spitsbergen (Svalbard, Norway) for the Comanche Carbonate at Gusev Crater, Mars

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    Carbonate occurs at the Comanche outcrops in Gusev Crater on the basis of analyses made by the Mars Exploration Rover Spirit [1]. Taken together, mineralogical data from Spirit's Moessbauer (MB) and Mini-TES spectrometer and chemical data from the APXS spectrometer show that Comanche carbonate has an Mg-Fe-rich bulk chemical composition, is present at high concentrations, and is distributed throughout the outcrop and not just at the MB and APXS analysis location. The granular outcrop texture and the observation that it appears to be resistant to weathering compared with surrounding material [1] imply that the carbonate may be present as a cement. A hydrothermal origin for the Comanche carbonate was inferred by analogy with laboratory experiments and with a carbonate occurrence within the Bockfjord volcanic complex on the island Spitsbergen (Svalbard, Norway) [1]. The laboratory carbonates, synthesized by precipitation from hydrothermal solutions, have (MB) parameters and average bulk chemical compositions that are characteristic of Comanche carbonate. The connection to Comanche carbonate is only through chemical data for certain occurrences of Spitsbergen carbonates. In fact, the common average bulk chemical composition for these Spitsbergen carbonates, the synthetic carbonates, the Comanche carbonate, and also the carbonate globules found in martian meteorite ALH84001 is a chemical constraint consistent with a hydrothermal formation process for all the carbonates [e.g., 1-3]. We develop here a link between MB data for the Comanche carbonate from MER and MB data for certain Spitsbergen carbonate occurrences from laboratory measurements. We also obtained visible and near- IR spectra on Spitsbergen carbonates for comparison with martian carbonate detections made on the basis of CRISM spectral data, e.g., in Nili Fossae [4]

    Mineralogical In-situ Investigation of Acid-Sulfate Samples from the Rio Tinto River, Spain, with a Portable XRD/XRF Instrument

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    A field campaign was organized in September 2006 by Centro de Astobiologica (Spain) and Washington University (St Louis, USA) for the geological study of the Rio Tinto river bed sediments using a suite of in-situ instruments comprising an ASD reflectance spectrometer, an emission spectrometer, panoramic and close-up color imaging cameras, a life detection system and NASA's CheMin 4 XRD/XRF prototype. The primary objectives of the field campaign were to study the geology of the site and test the potential of the instrument suite in an astrobiological investigation context for future Mars surface robotic missions. The results of the overall campaign will be presented elsewhere. This paper focuses on the results of the XRD/XRF instrument deployment. The specific objectives of the CheMin 4 prototype in Rio Tinto were to 1) characterize the mineralogy of efflorescent salts in their native environments; 2) analyze the mineralogy of salts and oxides from the modern environment to terraces formed earlier as part of the Rio Tinto evaporative system; and 3) map the transition from hematite-dominated terraces to the mixed goethite/salt-bearing terraces where biosignatures are best preserved

    CheMin: A Definitive Mineralogy Instrument in the Analytical Laboratory of the Mars Science Laboratory

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    An important goal of the Mars Science Laboratory (MSL '09) mission is the determination of definitive mineralogy and chemical composition. CheMin is a miniature X-ray diffraction/X-ray fluorescence (XRD/XRF) instrument that has been chosen for the analytical laboratory of MSL. CheMin utilizes a miniature microfocus source cobalt X-ray tube, a transmission sample cell and an energy-discriminating X-ray sensitive CCD to produce simultaneous 2-D X-ray diffraction patterns and X-ray fluorescence spectra from powdered or crushed samples. A diagrammatic view of the instrument is shown. Additional information is included in the original extended abstract
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