1,990 research outputs found

    We Have the War Upon Us: The Onset of the Civil War, November 1860-April 1861

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    A Reassessment of the Secession Crisis A prolific scholar, William J. Cooper, has made major contributions to our understanding of southern history, especially in the Civil War era. More than thirty years ago, he clearly and convincingly affirmed slavery’s centrality to the politics of...

    The Road to Disunion, Vol. II: Secessionists Triumphant, 1854-1861

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    The South and Disunion The Complexity of Sectionalism and Secession The publication in 1990 of William W. Freehling\u27s Secessionists at Bay, 1776-1854 was a major event. The first volume of a projected two-volume magnum opus entitled The Road to Disunion, it launche...

    Inflation and financial market performance

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    An exploration of the cross-sectional relationship between inflation and an array of indicators of financial market conditions, using time-averaged data covering several decades and a large number of countries.Financial markets ; Inflation (Finance)

    A Photomicrographic Method for the Detection of Oxygen Content in the Hemoglobin of the Red Blood Cell

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    Previous attempts at photographing the hemoglobin in the red blood cells have been confined to the making of two separate images of the same blood sample; one image is recorded using a wavelength band in the isobestic point region of the spectral distribution of oxygenated and reduced blood, and the other image is made using a wavelength band of radiation in the area of greatest difference in absorption between the two blood states. The method described here attempts to obtain a measurement of oxygenation by means of only one exposure using both regions of wavelengths simultaneously. The response is the density on film of the images of the two blood samples as recorded on color reversal film. A dilute blood sample was deoxygenated with nitrogen gas using a closed chamber. The blood solution was then transfered to a closed 100 micrometer depth chamber through which photomicrographs were made. Fully oxygenated blood was photographed In the same manner. Microdensitometric traces of the Images of individual oxygenated and reduced blood cells show that the meen density of the images of oxygenated hemoglobin in the cells was signifigantly greater than that of the reduced red blood cells

    Deep Reinforcement Learning for Tensegrity Robot Locomotion

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    Tensegrity robots, composed of rigid rods connected by elastic cables, have a number of unique properties that make them appealing for use as planetary exploration rovers. However, control of tensegrity robots remains a difficult problem due to their unusual structures and complex dynamics. In this work, we show how locomotion gaits can be learned automatically using a novel extension of mirror descent guided policy search (MDGPS) applied to periodic locomotion movements, and we demonstrate the effectiveness of our approach on tensegrity robot locomotion. We evaluate our method with real-world and simulated experiments on the SUPERball tensegrity robot, showing that the learned policies generalize to changes in system parameters, unreliable sensor measurements, and variation in environmental conditions, including varied terrains and a range of different gravities. Our experiments demonstrate that our method not only learns fast, power-efficient feedback policies for rolling gaits, but that these policies can succeed with only the limited onboard sensing provided by SUPERball's accelerometers. We compare the learned feedback policies to learned open-loop policies and hand-engineered controllers, and demonstrate that the learned policy enables the first continuous, reliable locomotion gait for the real SUPERball robot. Our code and other supplementary materials are available from http://rll.berkeley.edu/drl_tensegrityComment: International Conference on Robotics and Automation (ICRA), 2017. Project website link is http://rll.berkeley.edu/drl_tensegrit

    IDENTIFYING HIGHLY CONSERVED PATHOGENICITY GENES IN CHESTNUT BLIGHT AND POWDERY MILDEW FUNGI AS TARGETS FOR NOVEL FORMS OF HOST RESISTANCE

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    A bioinformatic search of the genomes of chestnut blight fungus, Cryphonectria parasitica (Cp), and the Arabidopsis powdery mildew fungus, Golovinomyces cichoracearum (Gc), yielded six suspected pathogenicity genes with homologues in both species. Deletion of these genes by homologous gene replacement was attempted in Cp, with one success, TG4. The TG4-knockout strain showed changes in phenotype and reduced fungal virulence against chestnut. TG4 appears to be a promising target for host-induced gene silencing (HIGS) in transgenic American chestnut. The use of homologues from genetically tractable species like Cp can help overcome the obstacles to performing reverse genetics on intractable, biotrophic fungi such as Gc. Experiments underway involving the silencing and ectopic overexpression of the Gc homologues of the target genes provide a rapid method to study Cp genes, including to screen additional candidate genes as future targets for HIGS
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