3,574 research outputs found

    Microarray analysis of spring barley cultivars displaying differing sensitivity to physiological leaf spot (PLS)

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    peer-reviewedPhysiological leaf spot (PLS) is a disorder of spring barley (Hordeum vulgare L.), which has become more pronounced in recent years. The initial symptoms are small chlorotic/brown spots on the upper four leaves, which may develop into necrotic lesions with an irregular shape. As PLS occurs on leaves that are directly exposed to sunlight, it is thought that high light stress could be a trigger for the condition. This study concentrates on two cultivars, Cooper and Crusader, which display differential sensitivity to PLS. Biochemical measurements and enzyme assays revealed substantial difference in levels of ascorbate, type III peroxidases, and superoxide dismutase between the chosen cultivars during the 2003 growing season. A global gene expression study, using these field samples, was performed by microarray analysis. This supported the biochemical findings and highlighted additional sets of genes differentially expressed between the cultivars. Transcripts of particular interest, which appeared, included calcium signalling genes, cold-responsive genes and those involved in the assembly of Photosystem I. We conclude that susceptibility to PLS is related to levels of expression of genes with a role in countering the effects of oxidative stress.Teagasc Walsh Fellowship Programm

    The Federal Reserve's Primary Dealer Credit Facility

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    As liquidity conditions in the "repo market"--the market where broker-dealers obtain financing for their securities--deteriorated following the near-bankruptcy of Bear Stearns in March 2008, the Federal Reserve took the step of creating a special facility to provide overnight loans to dealers that have a trading relationship with the Federal Reserve Bank of New York. Six months later, in the wake of new strains in the repo market, the Fed expanded the facility by broadening the types of collateral accepted for loans. Both initiatives were designed to help restore the orderly functioning of the market and to prevent the spillover of distress to other financial firms.Federal Reserve Bank of New York ; Loans ; Financial crises ; Brokers

    Graphic, Identity Symbol Theories and the Creation of an Institutional Graphic Image

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    Exoskeleton master controller with force-reflecting telepresence

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    A thorough understanding of the requirements for successful master-slave robotic systems is becoming increasingly desirable. Such systems can aid in the accomplishment of tasks that are hazardous or inaccessible to humans. Although a history of use has proven master-slave systems to be viable, system requirements and the impact of specifications on the human factors side of system performance are not well known. In support of the next phase of teleoperation research being conducted at the Armstrong Research Laboratory, a force-reflecting, seven degree of freedom exoskeleton for master-slave teleoperation has been concepted, and is presently being developed. The exoskeleton has a unique kinematic structure that complements the structure of the human arm. It provides a natural means for teleoperating a dexterous, possibly redundant manipulator. It allows ease of use without operator fatigue and faithfully follows human arm and wrist motions. Reflected forces and moments are remotely transmitted to the operator hand grip using a cable transmission scheme. This paper presents the exoskeleton concept and development results to date. Conceptual design, hardware, algorithms, computer architecture, and software are covered

    Research studies on advanced optical module/head designs for optical devices

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    A summary is presented of research in optical data storage materials and of research at the center. The first section contains summary reports under the general headings of: (1) Magnetooptic media: modeling, design, fabrication, characterization, and testing; (2) Optical heads: holographic optical elements; and (3) Optical heads: integrated optics. The second section consist of a proposal entitled, Signal Processing Techniques for Optical Data Storage. And section three presents various publications prepared by the center

    Recent Decisions

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    Research Studies on Advanced Optical Module/Head Designs for Optical Disk Recording Devices

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    The Annual Report of the Optical Data Storage Center of the University of Arizona is presented. Summary reports on continuing projects are presented. Research areas include: magneto-optic media, optical heads, and signal processing

    An Experimental Study of Turbidite Channel Deposits: Implications for Channel Evolution and Sandstone Deposits

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    Gaining a detailed understanding of turbidite bed sequences is important for the characterization of sandstone reservoir properties, correlation of well cores, and geological interpretation. Many factors influence the internal structure of sandstone reservoirs: source material, source location in time, transport processes, basin geometry, fan channel development and evolution to name a few. Sandstone deposits associated with channel complexes are easy to find but difficult to develop. Here, we conduct tank experiments of scaled sediment-laden turbidity currents traversing a submerged channel to: (1) establish a state-of-the-art data collection and data processing system that has the potential to gain a unique understanding of the processes and deposits that build submarine fan environments; and (2) to use the facility to demonstrate how the interaction of a depositive turbidity current with a sinuous channel may influence the geometry, spatial relationships and grain size sorting of sandstone deposits. Our data shows the construction of prominent levees, asymmetric levee growth, continuous channel overspill, enhanced channel overspill downstream of bend corners, and lobate-shaped lobe deposits. Our preliminary results are qualitative, but indicate that channel wavelength, bend curvature, and bend peak-to-peak amplitude may have strong controls on down-channel and cross-channel depositional patterns, deposit thickness and grain size sorting.ChevronTexaco (Firm

    Redox-mediated bypass of restriction point via skipping of G1pm

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    BACKGROUND: It is well known that cancer cells bypass the restriction point, R, and undergo uncontrolled cell proliferation. HYPOTHESIS AND EVIDENCE: We suggest here that fibrosarcoma cells enter G(1ps )directly from M, skipping G(1pm), hence bypassing R, in response to redox modulation. Evidence is presented from the published literature that demonstrate a shortening of the cycle period of transformed fibroblasts (SV-3T3) compared to the nontransformed 3T3 fibroblasts, corresponding to the duration of G(1pm )in the 3T3 fibroblasts. Evidence is also presented that demonstrate that redox modulation can induce the CUA-4 fibroblasts to bypass R, resulting in a cycle period closely corresponding to the cycle period of fibrosarcoma cells (HT1080). CONCLUSION: The evidence supports our hypothesis that a low internal redox potential can cause fibrosarcoma cells to skip the G(1pm )phase of the cell cycle
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