902 research outputs found

    Rapid Separations of Protactinium and Uranium Radioisotopes from Cyclotron Bombarded Thorium Nitrate

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71015/2/JCPSA6-20-4-754-1.pd

    Trace Analysis of Marine Organisms: A Comparison of Activation Analysis and Conventional Methods

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109766/1/lno1959440398.pd

    Rapid Radiochemical Separations

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/86135/1/NAS-NS-3104_Rapid_Separations.pd

    Activation Analyses Of Vanadium, Arsenic, Molybdenum, Tungsten, Rhenium, And Gold In Marine Organisms

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109999/1/lno1962720186.pd

    Frequency and Distribution of Extended Diapause in Nebraska Populations of \u3ci\u3eDiabrotica barberi\u3c/i\u3e (Coleoptera: Chrysomelidae)

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    The frequency of extended diapause in populations of the northern corn rootworm, Diabrotica barberi Smith & Lawrence (Coleoptera: Chrysomelidae), was measured in eastern Nebraska. Adult collections were made during late summer in 2008 and 2009 from eight sites each year (seven sites were consistent over years). Eggs were obtained from 12 to 20 females per site and were held on moist soil under appropriate temperature profiles to facilitate egg survival, diapause development, and diapause termination. Percentage egg hatch was recorded after the first and second year for the 2008 and 2009 collections. Additional extended diapause expression was estimated for the 2008 and 2009 collections by counting remaining live eggs after the second-year egg hatch was completed. These data also were used to estimate each site’s maximum egg viability. Results collectively indicate that the extended diapause trait was present in all eastern Nebraska populations; however, significant variation in the frequency of extended diapause was observed within and among D. barberi populations (first-year mean percentage egg hatch range: 2008 collections: 4.5–38.6%; 2009 collections: 10.7–42.5%). Geographically, the highest incidence of extended diapause was found along a north-south transect in eastern counties of Nebraska that parallels the Missouri River. In general, the frequency of extended diapause was lower in sites found west of the north-south transect. This study contributes to the knowledge base needed to develop appropriate D. barberi management strategies in Nebraska. These data can be used to pinpoint areas of Nebraska that may have the greatest risk of economic injury in first-year corn (Zea mays L.) when D. barberi densities are high

    Frequency and Distribution of Extended Diapause in Nebraska Populations of \u3ci\u3eDiabrotica barberi\u3c/i\u3e (Coleoptera: Chrysomelidae)

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    The frequency of extended diapause in populations of the northern corn rootworm, Diabrotica barberi Smith & Lawrence (Coleoptera: Chrysomelidae), was measured in eastern Nebraska. Adult collections were made during late summer in 2008 and 2009 from eight sites each year (seven sites were consistent over years). Eggs were obtained from 12 to 20 females per site and were held on moist soil under appropriate temperature profiles to facilitate egg survival, diapause development, and diapause termination. Percentage egg hatch was recorded after the first and second year for the 2008 and 2009 collections. Additional extended diapause expression was estimated for the 2008 and 2009 collections by counting remaining live eggs after the second-year egg hatch was completed. These data also were used to estimate each site’s maximum egg viability. Results collectively indicate that the extended diapause trait was present in all eastern Nebraska populations; however, significant variation in the frequency of extended diapause was observed within and among D. barberi populations (first-year mean percentage egg hatch range: 2008 collections: 4.5–38.6%; 2009 collections: 10.7–42.5%). Geographically, the highest incidence of extended diapause was found along a north-south transect in eastern counties of Nebraska that parallels the Missouri River. In general, the frequency of extended diapause was lower in sites found west of the north-south transect. This study contributes to the knowledge base needed to develop appropriate D. barberi management strategies in Nebraska. These data can be used to pinpoint areas of Nebraska that may have the greatest risk of economic injury in first-year corn (Zea mays L.) when D. barberi densities are high

    Isotropic-medium three-dimensional cloaks for acoustic and electromagnetic waves

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    We propose a generalization of the two-dimensional eikonal-limit cloak derived from a conformal transformation to three dimensions. The proposed cloak is a spherical shell composed of only isotropic media; it operates in the transmission mode and requires no mirror or ground plane. Unlike the well-known omnidirectional spherical cloaks, it may reduce visibility of an arbitrary object only for a very limited range of observation angles. In the short-wavelength limit, this cloaking structure restores not only the trajectories of incident rays, but also their phase, which is a necessary ingredient to complete invisibility. Both scalar-wave (acoustic) and transverse vector-wave (electromagnetic) versions are presented.Comment: 17 pages, 12 figure

    Extension of the Measurement Capabilities of the Quadrupole Resonator

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    The Quadrupole Resonator, designed to measure the surface resistance of superconducting samples at 400 MHz has been refurbished. The accuracy of its RF-DC compensation measurement technique is tested by an independent method. It is shown that the device enables also measurements at 800 and 1200 MHz and is capable to probe the critical RF magnetic field. The electric and magnetic field configuration of the Quadrupole Resonator are dependent on the excited mode. It is shown how this can be used to distinguish between electric and magnetic losses.Comment: 6 pages, g figure

    Indirect neutron absorptiometry

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    A preliminary account is given of the use of the neutron absorption of suitable elements (such as gadolinium) for the determination of non-absorbing elements (such as fluorine) by measuring the absorption of a dissolved precipitate (in the case quoted, gadolinium fluoride). This indirect determination by neutron absorption gives reproducible results rapidly and non-destructibly. The applications of the method are being studied.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32405/1/0000480.pd
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