Migration of radiogenic strontium during metamorphism

Study of the concentration and isotopic composition of strontium and rubidium in hornblende diorite dikes and sills of Precambrian age from the Panamint Mountains of California showed that these rock systems were enriched in radiogenic Sr during a late Mesozoic metamorphism. Enrichments in radiogenic Sr were observed for total-rock samples which yielded apparent ages of up to 34,000 m.y., although there is no obvious petrographic evidence for such metasomatic changes. These results indicate that some caution is necessary in interpreting the Sr isotopic composition of rocks in terms of their original source or in assuming that ‘total rocks’ form closed systems. In general, the initial isotopic Sr composition should be determined, not assumed

Living on the Precipice: A Conversation with Edward Albee

An edited version of the Writers Forum interview dated February 5, 1981. Speaking with Edward Albee were Stan Sanvel Rubin, the current director of·the Forum; Adam Lazarre, the former Dean of Fine Arts; and Mark Anderson, who teaches Renaissance and contemporary drama

Report of the Terrestrial Bodies Science Working Group. Volume 5: Mars

Present knowledge of the global properties and surface characteraretics of Mars and the composition and dynamics of its atmosphere are reviewed. The objectives of proposed missions, the exploration strategy, and supporting research and technology required are delineated

Performance and durability of HgI_2 X-ray detectors for space missions

Considerable progress has been achieved in HgI_2 detector fabrication technology and amplification electronics. An energy resolution of 198 eV (full width at half maximum) has been obtained for the Mn K_α line of 5.9 keV in a practical X-ray probe without the use of cryogenic cooling. Detectors prepared with Parylene-C encapsulation have demonstrated perfect reliability in two-year tests under high vacuum and temperature and bias cycling. Other HgI_2 detectors have been used to demonstrate proton-radiation-damage resistance to levels of 10^(12) protons/cm^2 at 10.7 MeV. It is concluded that HgI_2 detectors are suitable for the ordinary requirements of energy dispersive detectors in X-ray spectroscopy systems

The location of Airy-0, the Mars prime meridian reference, from stereo photogrammetric processing of THEMIS IR imaging and digital elevation data

The small crater Airy-0 was selected from Mariner 9 images to be the reference for the Mars prime meridian. Initial analyses in the year 2000 tied Viking Orbiter and Mars Orbiter Camera images of Airy-0 to the evolving Mars Orbiter Laser Altimeter global digital terrain model to update the location of Airy-0. Based upon this tie and radiometric tracking of landers/rovers from Earth, new expressions for the Mars spin axis direction, spin rate, and prime meridian epoch value were produced to define the orientation of the Martian surface in inertial space over time. Since the Mars Global Surveyor mission and Mars Orbiter Laser Altimeter global digital terrain model were completed some time ago, a more exhaustive study has been performed to determine the accuracy of the Airy-0 location and orientation of Mars at the standard epoch. Thermal Emission Imaging System (THEMIS) IR image cubes of the Airy and Gale crater regions were tied to the global terrain grid using precision stereo photogrammetric image processing techniques. The Airy-0 location was determined to be about 0.001° east of its predicted location using the currently defined International Astronomical Union (IAU) prime meridian location. Information on this new location and how it was derived will be provided to the NASA Mars Exploration Program Geodesy and Cartography Working Group for their assessment. This NASA group will make a recommendation to the IAU Working Group on Cartographic Coordinates and Rotational Elements to update the expression for the Mars spin axis direction, spin rate, and prime meridian location

Intensity of Grazing Effect on Livestock and Forage Production

An intensity of grazing experiment was initiated in 1942 at the Cottonwood Range Field Station to study the effects of heavy, moderate, and light grazing on the vegetation and on cow and calf production. Results of the first 9 years of this study were reported in South Dakota Agricultural Experiment Station Bulletin 412 in 1951. These studies have been continued and intensified. The present publication is a progress report on the effects of the intensity of grazing on cow and calf production since 1953 and on the cumulative effects of different grazing intensities on the native vegetation

Low Energy X-Ray Spectra Measured with a Mercuric Iodide Energy Dispersive Spectrometer in a Scanning Electron Microscope

A mercuric iodide energy dispersive x-ray spectrometer, with Peltier cooling provided for the detector and input field effect transistor, has been developed and tested in a scanning electron microscope. X-ray spectra were obtained with the 15 keV electron beam. An energy resolution of 225 eV (FWHM) for Mn-Kα at 5.9 keV and 195 eV (FWHM) for Mg-K line at 1.25 keV has been measured. Overall system noise level was 175 eV (FWHM). The detector system characterization with a carbon target demonstrated good energy sensitivity at low energies and lack of significant spectral artifacts at higher energies

Advances in the development of encapsulants for mercuric iodide X-ray detectors

Advances in the development of protective impermeable encapsulants with high transparency to ultra-low-energy X-rays for use on HgI_2 X-ray detectors are reported. Various X-ray fluorescence spectra from coated detectors are presented. The X-ray absorption in the encapsulants has been analyzed using characteristic radiation from various elements. Results suggest that low-energy cutoffs for the detectors are not determined solely by the encapsulating coatings presently employed but are also influenced by the front electrode and surface effects, which can affect the local electric field or the surface recombination velocity. An energy resolution of 182 eV (FWHM) has been achieved for Ni L lines at 850 eV. Improved detector sensitivity to X-ray energies under 700 eV is demonstrated

Creating new consultation programs in community mental health centers: Analysis of a case study

A primary prevention program, initiated in a community mental health center, never became fully operational. Analysis suggests that failure to include recipients in initial planning, an unrealistic time table, insufficient institutional support for innovation, the project leader's organizational marginality, and the institutional constraints created by commitment to direct treatment of troubled individuals were factors that contributed to the project's failure. Several recommendations are presented. The most novel and important one is that systems-oriented, preventive mental health work should be based in a separate, distinct institution .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44297/1/10597_2005_Article_BF01410882.pd