4,086 research outputs found

    An extreme ultraviolet spectrometer experiment for the Shuttle Get Away Special Program

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    An extreme ultraviolet (EUV) spectrometer experiment operated successfully during the STS-7 mission in an experiment to measure the global and diurnal variation of the EUV airglow. The spectrometer is an F 3.5 Wadsworth mount with mechanical collimator, a 75 x 75 mm grating, and a bare microchannel plate detector providing a spectral resolution of 7 X FWHM. Read-out of the signal is through discrete channels or resistive anode techniques. The experiment includes a microcomputer, 20 Mbit tape recorder, and a 28V, 40 Ahr silver-zinc battery. It is the first GAS payload to use an opening door. The spectrometer's 0.1 x 4.2 deg field of view is pointed vertically out of the shuttle bay. During the STS-7 flight data were acquired continuously for a period of 5 hours and 37 minutes, providing spectra of the 570 A to 850 A wavelength region of the airglow. Five diurnal cycles of the 584 A emission of neutral helium and the 834 A emission of ionized atomic oxygen were recorded. The experiment also recorded ion events and pressure pulses associated with thruster firings. The experiment is to fly again on Mission 41-F

    Visible and near-ultraviolet spectroscopy at Thule AFB (76.5 N) from January 28 - February 15, 1988

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    Near-ultraviolet and visible spectrographs identical to those employed at McMurdo Station, Antarctica (77.8 S) during the austral spring seasons of 1986 and 1987 were used to study the stratosphere above Thule, Greenland (76.5 N) during early spring, 1988. Observations were carried out both at night using the direct moon as a light source, and during the day by collecting the scattered light from the zenith sky when solar zenith angles were less than about 94.5 degrees. Excellent meteorological conditions prevailed in the troposphere and stratosphere at Thule. Surface weather was extremely clear over most of the period, facilitating measurements of the direct light from the moon. The lower stratospheric arctic polar vortex was located very near Thule throughout the observing period, and temperature at the 30 mbar level were typically below -80 C above Thule, according to the National Meteorological Center daily analyses. Thus conditions were favorable for polar stratospheric cloud formation above Thule. Total column ozone abundances were about 350 to 400 Dobson units, and did not suggest a clear temporal trend over the observing period. Stratospheric nitrogen dioxide measurements were complicated by the presence of a large component of tropospheric pollution on many occasions. Stratospheric nitrogen dioxide could be identified on most days using the absorption in the scattered light from the zenith sky, which greatly enhances the stratospheric airmass while suppressing the tropospheric contribution. These measurements suggest that the total vertical column abundance of nitrogen dioxide present over Thule in February was extremely low, sometimes as low as 3 x 10 to the 14th per sq cm. The abundance of nitrogen dioxide increased systemically from about 3 x 10 to the 14th in late January to 1.0 x 10 to the 15th per sq cm in mid-February, perhaps because of photolysis of N2O5 in the upper part of the stratosphere, near 25 to 35 km

    Near UV atmospheric absorption measurements from the DC-8 aircraft during the 1987 airborne Antarctic ozone experiment

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    During the Airborne Antarctic Ozone Experiment from 28 August to 30 September 1987 near UV zenith scattered sky measurements were made over Antarctic from the NASA DC-8 aircraft using a one third m spectrograph equipped with a diode-array detector. Scattered sky light data in the wavelength range 348 nm to 388 nm was spectrally analyzed for O3, NO2, OClO, and BrO column abundances. Slant column abudances of O3, NO2, OClO and BrO were determined, using a computer algorithm of non-linear and linear least square correlation of Antarctic scattered sky spectra to laboratory absorption cross section data. Using measured vertical electrochemical sonde ozone profiles from Palmer, Halley Bay, and the South Pole Stations the slant columns of O3 were converted into vertical column abundances. The vertical column amounts of NO2, OClO, and BrO were derived using vertical profiles calculated by a chemical model appropriate for Antarctica. NO2 vertical column abundances show steep latitudinal decrease with increasing latitude for all 13 flights carried out during the mission. In the regions where NO2 abudances are low, OClO and BrO were observed. The spatial and temporal vertical column abundances of these species are discussed in the context of the chemistry and dynamics in the antarctic polar vortex during the austral spring

    Children, family and the state : revisiting public and private realms

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    The state is often viewed as part of the impersonal public sphere in opposition to the private family as a locus of warmth and intimacy. In recent years this modernist dichotomy has been challenged by theoretical and institutional trends which have altered the relationship between state and family. This paper explores changes to both elements of the dichotomy that challenge this relationship: a more fragmented family structure and more individualised and networked support for children. It will also examine two new elements that further disrupt any clear mapping between state/family and public/private dichotomies: the third party role of the child in family/state affairs and children's application of virtual technology that locates the private within new cultural and social spaces. The paper concludes by examining the rise of the 'individual child' hitherto hidden within the family/state dichotomy and the implications this has for intergenerational relations at personal and institutional levels

    Diagnostic comparison of three groups of examiners using visual and laser fluorescence methods to detect occlusal caries in vitro

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    The document attached has been archived with permission from the Australian Dental Association. An external link to the publisher’s copy is included.Background: To evaluate the accuracy of the DIAGNOdent laser device (DD) for detecting occlusal fissure caries when used by three groups of examiners. Methods: Three final-year dental students (S), three General Dental Practitioners (G), and three Academic Clinicians (A) individually examined the non-cavitated occlusal surfaces of 25 extracted permanent molars using visual inspection (VI) then DD assessments. The presence of caries was confirmed following tooth sectioning. A cut-off limit of 30 was used for the DD to avoid over-treatment in a low caries-risk situation. Results: For VI, individual examiner sensitivity (caries correctly diagnosed) ranged from 53 to 86 per cent, and specificity (sound teeth correctly diagnosed) ranged from 76 to 95 per cent, with low Kappa agreements. Group S achieved the highest sensitivity (80 per cent) and Groups G and A achieved the highest specificities (88 per cent). For DD, individual examiner sensitivity ranged from 19 to 77 per cent, and specificity from 71 to 97 per cent, with generally moderate Kappa agreements. Group A achieved the highest (67 per cent) and Group G the lowest (44 per cent) sensitivities, and Group G achieved the highest specificity (94 per cent). Conclusions: There were similar widely varying results for the two diagnostic methods and for the three groups of examiners. However, the relatively high sensitivities found with VI and specificities found with DD should avoid over-treatment in low caries-risk populations.L Fung, R Smale, H Ngo and G Moun

    Evaluation of GEOS-5 Sulfur Dioxide Simulations During the Frostburg, MD 2010 Field Campaign.

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    Sulfur dioxide (SO2) is a major atmospheric pollutant with a strong anthropogenic component mostly produced by the combustion of fossil fuel and other industrial activities. As a precursor of sulfate aerosols that affect climate, air quality, and human health, this gas needs to be monitored on a global scale. Global climate and chemistry models including aerosol processes along with their radiative effects are important tools for climate and air quality research. Validation of these models against in-situ and satellite measurements is essential to ascertain the credibility of these models and to guide model improvements. In this study the Goddard Chemistry, Aerosol, Radiation, and Transport (GOCART) module running on-line inside the Goddard Earth Observing System version 5 (GEOS-5) model is used to simulate aerosol and SO2 concentrations. Data taken in November 2010 over Frostburg, Maryland during an SO2 field campaign involving ground instrumentation and aircraft are used to evaluate GEOS-5 simulated SO2 concentrations. Preliminary data analysis indicated the model overestimated surface SO2 concentration, which motivated the examination of mixing processes in the model and the specification of SO2 anthropogenic emission rates. As a result of this analysis, a revision of anthropogenic emission inventories in GEOS-5 was implemented, and the vertical placement of SO2 sources was updated. Results show that these revisions improve the model agreement with observations locally and in regions outside the area of this field campaign. In particular, we use the ground-based measurements collected by the United States Environmental Protection Agency (US EPA) for the year 2010 to evaluate the revised model simulations over North America

    A DNA nanoswitch incorporating the fluorescent base analogue 2-aminopurine detects single nucleotide mismatches in unlabelled targets

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    DNA nanoswitches can be designed to detect unlabelled nucleic acid targets and have been shown to discriminate between targets which differ in the identity of only one base. This paper demonstrates that the fluorescent base analogue 2-aminopurine (AP) can be used to discriminate between nanoswitches with and without targets and to discriminate between matched and mismatched targets. In particular, we have used both steady-state and time-resolved fluorescence spectroscopy to determine differences in AP environment at the branchpoint of nanoswitches assembled using complementary targets and targets which incorporate single base mismatches

    Food processing and technology 1978: a summary of research

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    Evaluation of tomato cultivars for processing / W. A. Gould, W. Stone, J. Mount, L. Witt, Y. Yamada, and S. Z. Berry -- Geotrichum candidum in midwestern tomato processing plants and various methods of inhibiting its growth / James G. Fox and Wilbur A. Gould -- Effects of various qualities of raw tomatoes (subjective evaluation) on color of extractable juice (objective evaluation) / Yasunori Yamada and Wilbur A. Gould -- Protein content of seeds taken from tomatoes at various stages of ripeness / Daniel Brodowski and J. R. Geisman -- Effects of cultivar, break temperature, and extraction methods on the viscosity of tomato juice / Hashmy Bel-Haj and Wilbur A. Gould -- A study of some factors affecting the solid content of canned tomatoes / J. R. Mount and W. A. Gould -- Prediction of ascorbic acid stability in canned apple juice / Mohamed I. Mahmoud and Wilbur A. Gould -- Investigation of protein content of ohio grown soybeans / Girish N. Desai and Andrew C. Peng -- Recovery and functionality of soybean leaf proteins / Mohammed H. Ali and Andrew C. Peng -- Carotene content of green snap beans / H. Fenercioglu and D. E. Crean -- Effect of reconditioning on the ascorbic acid content of potato cultivars / I. S. Arkoudilos and D. E. Crean -- Kinetic studies of polyphenol oxidase from HiDri cabbage / Ling-May Chen and Andrew C. Peng -- Refinements in pickle brine recycling / T. Glares and J. R. Geisman -- Use of ultraviolet light to inhibit Staphylococcus aureus growth on the surface of baked pumpkin pie / Nicholas N. Kallas and Wilbur A. Gould -- Development of a nutritionally improved corn masa / Thomas H. Rieman and Wilbur A. Gould -- Mechanical deboning of Lake Erie freshwater drum / W. E. Stone and W. A. Gould -- Lake Erie freshwater drum fillet processing, storage, and evaluation / W. E. Stone and W. A. Goul

    Identification of Radiopure Titanium for the LZ Dark Matter Experiment and Future Rare Event Searches

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    The LUX-ZEPLIN (LZ) experiment will search for dark matter particle interactions with a detector containing a total of 10 tonnes of liquid xenon within a double-vessel cryostat. The large mass and proximity of the cryostat to the active detector volume demand the use of material with extremely low intrinsic radioactivity. We report on the radioassay campaign conducted to identify suitable metals, the determination of factors limiting radiopure production, and the selection of titanium for construction of the LZ cryostat and other detector components. This titanium has been measured with activities of 238^{238}Ue_{e}~<<1.6~mBq/kg, 238^{238}Ul_{l}~<<0.09~mBq/kg, 232^{232}The_{e}~=0.28±0.03=0.28\pm 0.03~mBq/kg, 232^{232}Thl_{l}~=0.25±0.02=0.25\pm 0.02~mBq/kg, 40^{40}K~<<0.54~mBq/kg, and 60^{60}Co~<<0.02~mBq/kg (68\% CL). Such low intrinsic activities, which are some of the lowest ever reported for titanium, enable its use for future dark matter and other rare event searches. Monte Carlo simulations have been performed to assess the expected background contribution from the LZ cryostat with this radioactivity. In 1,000 days of WIMP search exposure of a 5.6-tonne fiducial mass, the cryostat will contribute only a mean background of 0.160±0.0010.160\pm0.001(stat)±0.030\pm0.030(sys) counts.Comment: 13 pages, 3 figures, accepted for publication in Astroparticle Physic
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