351 research outputs found

    In Flight From Politics: Social History and Its Discontents

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    Also CSST Working Paper #41.http://deepblue.lib.umich.edu/bitstream/2027.42/51182/1/415.pd

    Comparison of long‐period surface wave amplitude and phase anomalies for two models of global lateral heterogeneity

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95459/1/grl2883.pd

    Changes in cellular phenotype and resistance to cisplatin in an oral squamous carcinoma model over-expressing cytoglobin

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    Although cytoglobin is widely considered a tumour suppressor, re-expression plays a role in disease progression in a subset of oral squamous cell carcinomas (OSC), but the mechanism of action is not understood. In this thesis, we developed a new OSC cell model to study the effects of cytoglobin over­ expression on cellular phenotype and resistance to cisplatin. Microarray analysis of cytoglobin­ expressing cells showed significantly altered transcripts related to stress response, adhesion and locomotion, and metabolism. Treatment of cytoglobin-expressing cells with cisplatin revealed a greater response in p53-regulated target expression (MAP3K5, NQOl, CDKN2A and GADD45A) compared to non-expressing cells. Further investigation showed this was associated with higher CHKl, p53 and p21 protein levels, suggesting enhanced activation of p53 signalling pathways. Furthermore, cytoglobin-expressing cells were more resistant to cisplatin-induced apoptosis and altered their cell cycle distribution. These changes were linked to reduced total cellular and mitochondrial superoxide. Collectively, these findings demonstrate for the first time that cytoglobin over- expression is associated with resistance to cisplatin-induced cytotoxicity and the mechanism involves p53 signalling. In conclusion, we propose expression of cytoglobin may afford tumours cells a survival advantage in the harsh environmental conditions of the developing tumour as well as resistance to drugs like cisplatin

    Test of the lower mantle slab penetration hypothesis using broadband S waves

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95293/1/grl3310.pd

    General properties of cosmological models with an Isotropic Singularity

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    Much of the published work regarding the Isotropic Singularity is performed under the assumption that the matter source for the cosmological model is a barotropic perfect fluid, or even a perfect fluid with a γ\gamma-law equation of state. There are, however, some general properties of cosmological models which admit an Isotropic Singularity, irrespective of the matter source. In particular, we show that the Isotropic Singularity is a point-like singularity and that vacuum space-times cannot admit an Isotropic Singularity. The relationships between the Isotropic Singularity, and the energy conditions, and the Hubble parameter is explored. A review of work by the authors, regarding the Isotropic Singularity, is presented.Comment: 18 pages, 1 figur

    The Effect of Silicon on Osmotic and Drought Stress Tolerance in Wheat Landraces

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    Drought stress reduces annual global wheat yields by 20%. Silicon (Si) fertilisation has been proposed to improve plant drought stress tolerance. However, it is currently unknown if and how Si affects different wheat landraces, especially with respect to their innate Si accumulation properties. In this study, significant and consistent differences in Si accumulation between landraces were identified, allowing for the classification of high Si accumulators and low Si accumulators. Landraces from the two accumulation groups were then used to investigate the effect of Si during osmotic and drought stress. Si was found to improve growth marginally in high Si accumulators during osmotic stress. However, no significant effect of Si on growth during drought stress was found. It was further found that osmotic stress decreased Si accumulation for all landraces whereas drought increased it. Overall, these results suggest that the beneficial effect of Si commonly reported in similar studies is not universal and that the application of Si fertiliser as a solution to agricultural drought stress requires detailed understanding of genotype-specific responses to Si

    Morphological assessment of the retina in uveitis

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    BACKGROUND: The objective of this study is to describe a system for color photograph evaluation in uveitis and report baseline morphologic findings for the Multicenter Uveitis Steroid Treatment (MUST) Trial. Four-hundred seventy-nine eyes of 255 subjects with intermediate, posterior, and panuveitis had stereoscopic color fundus photographs obtained by certified photographers and evaluated by certified graders using standardized procedures to evaluate morphologic characteristics of uveitis. The posterior pole was evaluated for macular edema, vitreoretinal interface abnormalities, and macular pigment disturbance/atrophy; the optic disk was assessed for edema, pallor, or glaucomatous changes. The presence of neovascularization, vascular occlusion, vascular sheathing, and tractional retinal changes was determined. A random subset of 77 images was re-graded to determine the percentage agreement with the original grading on a categorical scale. RESULTS: At baseline, 437/479 eyes had images available to grade. Fifty-three eyes were completely ungradable due to media opacity. Common features of intermediate and posterior/panuveitis were epiretinal membrane (134 eyes, 35 %), and chorioretinal lesions (140 eyes, 36 %). Macular edema was seen in 16 %. Optic nerve head and vascular abnormalities were rare. Reproducibility evaluation found exact agreement for the presence of chorioretinal lesions was 78 %, the presence and location of macular edema was 71 %, and the presence of epiretinal membrane was 71 %. Vertical cup-to-disk ratio measurement had intra-class correlation of 0.75. CONCLUSIONS: The MUST system for evaluating stereoscopic color fundus photographs describes the morphology of uveitis and its sequelae, in a standardized manner, is highly reproducible, and allows monitoring of treatment effect and safety evaluation regarding these outcomes in clinical trials

    Impacts of Waste from Concentrated Animal Feeding Operations on Water Quality

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    Waste from agricultural livestock operations has been a long-standing concern with respect to contamination of water resources, particularly in terms of nutrient pollution. However, the recent growth of concentrated animal feeding operations (CAFOs) presents a greater risk to water quality because of both the increased volume of waste and to contaminants that may be present (e.g., antibiotics and other veterinary drugs) that may have both environmental and public health importance. Based on available data, generally accepted livestock waste management practices do not adequately or effectively protect water resources from contamination with excessive nutrients, microbial pathogens, and pharmaceuticals present in the waste. Impacts on surface water sources and wildlife have been documented in many agricultural areas in the United States. Potential impacts on human and environmental health from long-term inadvertent exposure to water contaminated with pharmaceuticals and other compounds are a growing public concern. This work-group, which is part of the Conference on Environmental Health Impacts of Concentrated Animal Feeding Operations: Anticipating Hazards—Searching for Solutions, identified needs for rigorous ecosystem monitoring in the vicinity of CAFOs and for improved characterization of major toxicants affecting the environment and human health. Last, there is a need to promote and enforce best practices to minimize inputs of nutrients and toxicants from CAFOs into freshwater and marine ecosystems

    Effects of off great-circle propagation on the phase of long-period surface waves

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    Surface wave phase corrections for departures from great-circle propagation are computed using two-point ray-tracing through the aspherical earth model M84C of Woodhouse & Dziewonski (1984). For Rayleigh and Love waves with periods in the range 100–250 s, we determine whether these corrections provide significant variance reductions in source determinations compared with corrections calculated assuming great-circle propagation through the heterogeneous structure. For most source-receiver geometries, the off great-circle travel-time effects are small (< 10 s) for second and third orbits (e.g. R2 and R3), and their application in source determinations does not significantly reduce the data variance. This suggests that for the loworder heterogeneous models currently available the geometrical optics approximation is valid for long-period low orbit surface waves. Off great-circle phase anomalies increase quasi-linearly with increasing orbit number, indicating that the geometrical optics approximation degrades for higher orbits, which emphasizes the importance of developing higher order approximations for free-oscillation studies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73147/1/j.1365-246X.1987.tb05217.x.pd
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