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Sample records for mars-gram sensitivity studies

  1. Strategies to Improve the Accuracy of Mars-GRAM Sensitivity Studies at Large Optical Depths

    NASA Technical Reports Server (NTRS)

    Justh, Hilary L.; Justus, Carl G.; Badger, Andrew M.

    2010-01-01

    The poster provides an overview of techniques to improve the Mars Global Reference Atmospheric Model (Mars-GRAM) sensitivity. It has been discovered during the Mars Science Laboratory (MSL) site selection process that the Mars Global Reference Atmospheric Model (Mars-GRAM) when used for sensitivity studies for TES MapYear = 0 and large optical depth values such as tau = 3 is less than realistic. A preliminary fix has been made to Mars-GRAM by adding a density factor value that was determined for tau = 0.3, 1 and 3.

  2. Mars-GRAM: Increasing the Precision of Sensitivity Studies at Large Optical Depths

    NASA Technical Reports Server (NTRS)

    Justh, Hilary L.; Justus, C. G.; Badger, Andrew M.

    2010-01-01

    The Mars Global Reference Atmospheric Model (Mars-GRAM) is an engineering-level atmospheric model widely used for diverse mission applications. Mars-GRAM's perturbation modeling capability is commonly used, in a Monte-Carlo mode, to perform high fidelity engineering end-to-end simulations for entry, descent, and landing (EDL). It has been discovered during the Mars Science Laboratory (MSL) site selection process that Mars-GRAM, when used for sensitivity studies for MapYear=0 and large optical depth values such as tau=3, is less than realistic. A comparison study between Mars atmospheric density estimates from Mars-GRAM and measurements by Mars Global Surveyor (MGS) has been undertaken for locations of varying latitudes, Ls, and LTST on Mars. The preliminary results from this study have validated the Thermal Emission Spectrometer (TES) limb data. From the surface to 80 km altitude, Mars-GRAM is based on the NASA Ames Mars General Circulation Model (MGCM). MGCM results that were used for Mars-GRAM with MapYear=0 were from a MGCM run with a fixed value of tau=3 for the entire year at all locations. This has resulted in an imprecise atmospheric density at all altitudes. To solve this pressure-density problem, density factor values were determined for tau=.3, 1 and 3 that will adjust the input values of MGCM MapYear 0 pressure and density to achieve a better match of Mars-GRAM MapYear 0 with TES observations for MapYears 1 and 2 at comparable dust loading. The addition of these density factors to Mars-GRAM will improve the results of the sensitivity studies done for large optical depths.

  3. Updating Mars-GRAM to Increase the Accuracy of Sensitivity Studies at Large Optical Depths

    NASA Technical Reports Server (NTRS)

    Justh, Hiliary L.; Justus, C. G.; Badger, Andrew M.

    2010-01-01

    The Mars Global Reference Atmospheric Model (Mars-GRAM) is an engineering-level atmospheric model widely used for diverse mission applications. Mars-GRAM s perturbation modeling capability is commonly used, in a Monte-Carlo mode, to perform high fidelity engineering end-to-end simulations for entry, descent, and landing (EDL). During the Mars Science Laboratory (MSL) site selection process, it was discovered that Mars-GRAM, when used for sensitivity studies for MapYear=0 and large optical depth values such as tau=3, is less than realistic. From the surface to 80 km altitude, Mars-GRAM is based on the NASA Ames Mars General Circulation Model (MGCM). MGCM results that were used for Mars-GRAM with MapYear set to 0 were from a MGCM run with a fixed value of tau=3 for the entire year at all locations. This has resulted in an imprecise atmospheric density at all altitudes. As a preliminary fix to this pressure-density problem, density factor values were determined for tau=0.3, 1 and 3 that will adjust the input values of MGCM MapYear 0 pressure and density to achieve a better match of Mars-GRAM MapYear 0 with Thermal Emission Spectrometer (TES) observations for MapYears 1 and 2 at comparable dust loading. Currently, these density factors are fixed values for all latitudes and Ls. Results will be presented from work being done to derive better multipliers by including variation with latitude and/or Ls by comparison of MapYear 0 output directly against TES limb data. The addition of these more precise density factors to Mars-GRAM 2005 Release 1.4 will improve the results of the sensitivity studies done for large optical depths.

  4. Improving Mars-GRAM: Increasing the Accuracy of Sensitivity Studies at Large Optical Depths

    NASA Technical Reports Server (NTRS)

    Justh, Hilary L.; Justus, C. G.; Badger, Andrew M.

    2010-01-01

    Extensively utilized for numerous mission applications, the Mars Global Reference Atmospheric Model (Mars-GRAM) is an engineering-level atmospheric model. In a Monte-Carlo mode, Mars-GRAM's perturbation modeling capability is used to perform high fidelity engineering end-to-end simulations for entry, descent, and landing (EDL). Mars-GRAM has been found to be inexact when used during the Mars Science Laboratory (MSL) site selection process for sensitivity studies for MapYear=0 and large optical depth values such as tau=3. Mars-GRAM is based on the NASA Ames Mars General Circulation Model (MGCM) from the surface to 80 km altitude. Mars-GRAM with the MapYear parameter set to 0 utilizes results from a MGCM run with a fixed value of tau=3 at all locations for the entire year. Imprecise atmospheric density and pressure at all altitudes is a consequence of this use of MGCM with tau=3. Density factor values have been determined for tau=0.3, 1 and 3 as a preliminary fix to this pressure-density problem. These factors adjust the input values of MGCM MapYear 0 pressure and density to achieve a better match of Mars-GRAM MapYear 0 with Thermal Emission Spectrometer (TES) observations for MapYears 1 and 2 at comparable dust loading. These density factors are fixed values for all latitudes and Ls and are included in Mars-GRAM Release 1.3. Work currently being done, to derive better multipliers by including variations with latitude and/or Ls by comparison of MapYear 0 output directly against TES limb data, will be highlighted in the presentation. The TES limb data utilized in this process has been validated by a comparison study between Mars atmospheric density estimates from Mars-GRAM and measurements by Mars Global Surveyor (MGS). This comparison study was undertaken for locations on Mars of varying latitudes, Ls, and LTST. The more precise density factors will be included in Mars-GRAM 2005 Release 1.4 and thus improve the results of future sensitivity studies done for large

  5. Strategies to Improve the Accuracy of Mars-GRAM Sensitivity Studies at Large Optical Depths

    NASA Technical Reports Server (NTRS)

    Justh, Hilary L.; Justus, Carl G.; Badger, Andrew M.

    2009-01-01

    The Mars Global Reference Atmospheric Model (Mars-GRAM) is an engineering-level atmospheric model widely used for diverse mission applications. Mars-GRAM s perturbation modeling capability is commonly used, in a Monte-Carlo mode, to perform high fidelity engineering end-to-end simulations for entry, descent, and landing (EDL). It has been discovered during the Mars Science Laboratory (MSL) site selection process that Mars-GRAM when used for sensitivity studies for MapYear=0 and large optical depth values such as tau=3 is less than realistic. A comparison study between Mars atmospheric density estimates from Mars- GRAM and measurements by Mars Global Surveyor (MGS) has been undertaken for locations of varying latitudes, Ls, and LTST on Mars. The preliminary results from this study have validated the Thermal Emission Spectrometer (TES) limb data. From the surface to 80 km altitude, Mars- GRAM is based on the NASA Ames Mars General Circulation Model (MGCM). MGCM results that were used for Mars-GRAM with MapYear=0 were from a MGCM run with a fixed value of tau=3 for the entire year at all locations. Unrealistic energy absorption by uniform atmospheric dust leads to an unrealistic thermal energy balance on the polar caps. The outcome is an inaccurate cycle of condensation/sublimation of the polar caps and, as a consequence, an inaccurate cycle of total atmospheric mass and global-average surface pressure. Under an assumption of unchanged temperature profile and hydrostatic equilibrium, a given percentage change in surface pressure would produce a corresponding percentage change in density at all altitudes. Consequently, the final result of a change in surface pressure is an imprecise atmospheric density at all altitudes. To solve this pressure-density problem, a density factor value was determined for tau=.3, 1 and 3 that will adjust the input values of MGCM MapYear 0 pressure and density to achieve a better match of Mars-GRAM MapYear=0 with MapYears 1 and 2 MGCM output

  6. Strategies to Improve the Accuracy of Mars-GRAM Sensitivity Studies at Large Optical Depths

    NASA Astrophysics Data System (ADS)

    Justh, H. L.; Justus, C. G.; Badger, A. M.

    2009-12-01

    The Mars Global Reference Atmospheric Model (Mars-GRAM) is an engineering-level atmospheric model widely used for diverse mission applications. Mars-GRAM’s perturbation modeling capability is commonly used, in a Monte-Carlo mode, to perform high fidelity engineering end-to-end simulations for entry, descent, and landing (EDL). It has been discovered during the Mars Science Laboratory (MSL) site selection process that Mars-GRAM when used for sensitivity studies for MapYear=0 and large optical depth values such as tau=3 is less than realistic. A comparison study between Mars atmospheric density estimates from Mars-GRAM and measurements by Mars Global Surveyor (MGS) has been undertaken for locations of varying latitudes, Ls, and LTST on Mars. The preliminary results from this study have validated the Thermal Emission Spectrometer (TES) limb data. From the surface to 80 km altitude, Mars-GRAM is based on the NASA Ames Mars General Circulation Model (MGCM). MGCM results that were used for Mars-GRAM with MapYear=0 were from a MGCM run with a fixed value of tau=3 for the entire year at all locations. Unrealistic energy absorption by uniform atmospheric dust leads to an unrealistic thermal energy balance on the polar caps. The outcome is an inaccurate cycle of condensation/sublimation of the polar caps and, as a consequence, an inaccurate cycle of total atmospheric mass and global-average surface pressure. Under an assumption of unchanged temperature profile and hydrostatic equilibrium, a given percentage change in surface pressure would produce a corresponding percentage change in density at all altitudes. Consequently, the final result of a change in surface pressure is an imprecise atmospheric density at all altitudes. To solve this pressure-density problem, a density factor value was determined for tau=.3, 1 and 3 that will adjust the input values of MGCM MapYear 0 pressure and density to achieve a better match of Mars-GRAM MapYear 0 with MapYears 1 and 2 MGCM output

  7. Mars-GRAM 2010: Improving the Precision of Mars-GRAM

    NASA Technical Reports Server (NTRS)

    Justh, H. L.; Justus, C. G.; Ramey, H. S.

    2011-01-01

    It has been discovered during the Mars Science Laboratory (MSL) site selection process that the Mars Global Reference Atmospheric Model (Mars-GRAM) when used for sensitivity studies for Thermal Emission Spectrometer (TES) MapYear=0 and large optical depth values, such as tau=3, is less than realistic. Mars-GRAM's perturbation modeling capability is commonly used, in a Monte-Carlo mode, to perform high fidelity engineering end-to-end simulations for entry, descent, and landing (EDL). Mars-GRAM 2005 has been validated against Radio Science data, and both nadir and limb data from TES. Traditional Mars-GRAM options for representing the mean atmosphere along entry corridors include: (1) TES mapping year 0, with user-controlled dust optical depth and Mars-GRAM data interpolated from NASA Ames Mars General Circulation Model (MGCM) results driven by selected values of globally-uniform dust optical depth, or (2) TES mapping years 1 and 2, with Mars-GRAM data coming from MGCM results driven by observed TES dust optical depth. From the surface to 80 km altitude, Mars-GRAM is based on NASA Ames MGCM. Above 80 km, Mars-GRAM is based on the University of Michigan Mars Thermospheric General Circulation Model (MTGCM). MGCM results that were used for Mars-GRAM with MapYear=0 were from a MGCM run with a fixed value of tau=3 for the entire year at all locations. This choice of data has led to discrepancies that have become apparent during recent sensitivity studies for MapYear=0 and large optical depths. Unrealistic energy absorption by time-invariant atmospheric dust leads to an unrealistic thermal energy balance on the polar caps. The outcome is an inaccurate cycle of condensation/sublimation of the polar caps and, as a consequence, an inaccurate cycle of total atmospheric mass and global-average surface pressure. Under an assumption of unchanged temperature profile and hydrostatic equilibrium, a given percentage change in surface pressure would produce a corresponding percentage

  8. Mars-GRAM 2010: Additions and Resulting Improvements

    NASA Technical Reports Server (NTRS)

    Justh, Hilary L.; Burns, K. Lee

    2013-01-01

    The Mars Global Reference Atmospheric Model (Mars-GRAM) is an engineering-level atmospheric model widely used for diverse mission applications. Mars-GRAM has been utilized during previous aerobraking operations in the atmosphere of Mars. Mars-GRAM has also been used in the prediction and validation of Mars Pathfinder hypersonic aerodynamics, the aerothermodynamic and entry dynamics studies for Mars Polar Lander, the landing site selection process for the Mars Science Laboratory (MSL), the Mars Aerocapture System Study (MASS) as well as the Aerocapture Technology Assessment Group (TAG). Most recently, Mars-GRAM 2010 was used to develop the onboard atmospheric density estimator that is part of the Autonomous Aerobraking Development Plan. The most recent release of Mars-GRAM 2010 contains several changes including an update to Fortran 90/95 and the addition of adjustment factors. Following the completion of a comparison analysis between Mars-GRAM, Thermal Emission Spectrometer (TES), as well as Mars Global Surveyor (MGS), Mars Odyssey (ODY), and Mars Reconnaissance Orbiter (MRO) aerobraking density data, adjustment factors were added to Mars-GRAM 2010 that alter the input data from National Aeronautics and Space Administration (NASA) Ames Mars General Circulation Model (MGCM) and the University of Michigan Mars Thermospheric General Circulation Model (MTGCM) for the mapping year 0 user-controlled dust case. The addition of adjustment factors resolved the issue of previous versions of Mars-GRAM being less than realistic when used for sensitivity studies for mapping year 0 and large optical depth values, such as tau equal to 3. Mars-GRAM was evaluated at locations and times of TES limb observations and adjustment factors were determined. For altitudes above 80 km and below 135 km, Mars-GRAM (MTGCM) densities were compared to aerobraking densities measured by Mars Global Surveyor (MGS), Mars Odyssey (ODY), and Mars Reconnaissance Orbiter (MRO) to determine the adjustment

  9. The Next Generation of Mars-GRAM and Its Role in the Autonomous Aerobraking Development Plan

    NASA Technical Reports Server (NTRS)

    Justh, Hilary L.; Justus, Carl G.; Ramey, Holly S.

    2011-01-01

    The Mars Global Reference Atmospheric Model (Mars-GRAM) is an engineering-level atmospheric model widely used for diverse mission applications. Mars-GRAM 2010 is currently being used to develop the onboard atmospheric density estimator that is part of the Autonomous Aerobraking Development Plan. In previous versions, Mars-GRAM was less than realistic when used for sensitivity studies for Thermal Emission Spectrometer (TES) MapYear=0 and large optical depth values, such as tau=3. A comparison analysis has been completed between Mars-GRAM, TES and data from the Planetary Data System (PDS) resulting in updated coefficients for the functions relating density, latitude, and longitude of the sun. The adjustment factors are expressed as a function of height (z), Latitude (Lat) and areocentric solar longitude (Ls). The latest release of Mars-GRAM 2010 includes these adjustment factors that alter the in-put data from MGCM and MTGCM for the Mapping Year 0 (user-controlled dust) case. The greatest adjustment occurs at large optical depths such as tau greater than 1. The addition of the adjustment factors has led to better correspondence to TES Limb data from 0-60 km as well as better agreement with MGS, ODY and MRO data at approximately 90-135 km. Improved simulations utilizing Mars-GRAM 2010 are vital to developing the onboard atmospheric density estimator for the Autonomous Aerobraking Development Plan. Mars-GRAM 2010 was not the only planetary GRAM utilized during phase 1 of this plan; Titan-GRAM and Venus-GRAM were used to generate density data sets for Aerobraking Design Reference Missions. These data sets included altitude profiles (both vertical and along a trajectory), GRAM perturbations (tides, gravity waves, etc.) and provided density and scale height values for analysis by other Autonomous Aero-braking team members.

  10. Modeling Martian Dust Using Mars-GRAM

    NASA Technical Reports Server (NTRS)

    Justh, Hilary L.; Justus, C. G.

    2010-01-01

    Engineering-level atmospheric model widely used for diverse mission applications. Mars-GRAM s perturbation modeling capability is commonly used, in a Monte-Carlo mode, to perform high fidelity engineering end-to-end simulations for entry, descent, and landing (EDL). From the surface to 80 km altitude, Mars-GRAM is based on NASA Ames Mars General Circulation Model (MGCM). Mars-GRAM and MGCM use surface topography from Mars Global Surveyor Mars Orbiter Laser Altimeter (MOLA), with altitudes referenced to the MOLA areoid, or constant potential surface. Traditional Mars-GRAM options for representing the mean atmosphere along entry corridors include: TES Mapping Years 1 and 2, with Mars-GRAM data coming from MGCM model results driven by observed TES dust optical depth TES Mapping Year 0, with user-controlled dust optical depth and Mars-GRAM data interpolated from MGCM model results driven by selected values of globally-uniform dust optical depth. Mars-GRAM 2005 has been validated against Radio Science data, and both nadir and limb data from the Thermal Emission Spectrometer (TES).

  11. Global Summary MGS TES Data and Mars-Gram Validation

    NASA Technical Reports Server (NTRS)

    Justus, C.; Johnson, D.; Parker, Nelson C. (Technical Monitor)

    2002-01-01

    Mars Global Reference Atmospheric Model (Mars-GRAM 2001) is an engineering-level Mars atmosphere model widely used for many Mars mission applications. From 0-80 km, it is based on NASA Ames Mars General Circulation Model (MGCM), while above 80 km it is based on University of Arizona Mars Thermospheric General Circulation Model. Mars-GRAM 2001 and MGCM use surface topograph$ from Mars Global Surveyor Mars Orbiting Laser Altimeter (MOLA). Validation studies are described comparing Mars-GRAM with a global summary data set of Mars Global Surveyor Thermal Emission Spectrometer (TES) data. TES averages and standard deviations were assembled from binned TES data which covered surface to approx. 40 km, over more than a full Mars year (February, 1999 - June, 2001, just before start of a Mars global dust storm). TES data were binned in 10-by-10 degree latitude-longitude bins (i.e. 36 longitude bins by 19 latitude bins), 12 seasonal bins (based on 30 degree increments of Ls angle). Bin averages and standard deviations were assembled at 23 data levels (temperature at 21 pressure levels, plus surface temperature and surface pressure). Two time-of day bins were used: local time near 2 or 14 hours local time). Two dust optical depth bins wereused: infrared optical depth either less than or greater than 0.25 (which corresponds to visible optical depth either less than or greater than about 0.5). For interests in aerocapture and precision entry and landing, comparisons focused on atmospheric density. TES densities versus height were computed from TES temperature versus pressure, using assumptions of perfect gas law and hydrostatics. Mars-GRAM validation studies used density ratio (TES/Mars-GRAM) evaluated at data bin center points in space and time. Observed average TES/Mars-GRAM density ratios were generally 1+/-0.05, except at high altitudes (15-30 km, depending on season) and high latitudes (> 45 deg N), or at most altitudes in the southern hemisphere at Ls approx. 90 and 180deg

  12. Mars-Gram Validation with Mars Global Surveyor Data

    NASA Technical Reports Server (NTRS)

    Justus, C. G.; Johnson, D.; Parker, Nelson C. (Technical Monitor)

    2002-01-01

    Mars Global Reference Atmospheric Model (Mars-GRAM 2001) is an engineering-level Mars atmosphere model widely used for many b4ars mission applications. From 0-80 km, it is based on NASA Ames Mars General Circulation Model (MGCM), while above 80 km it is based on University of Arizona Mars Thermospheric General Circulation Model. Mars-GRAM 2001 and MGCM use surface topography from Mars Global Surveyor Mars Orbiting Laser Altimeter (MOLA). Validation studies are described comparing Mars-GRAM with Mars Global Surveyor Radio Science (RS) and Thermal Emission Spectrometer (TES) data. RS data from 2480 profiles were used, covering latitudes 75deg S to 72deg N, surface to approx. 40 km, for seasons ranging from areocentric longitude of Sun (Ls) = 70-160deg and 265-310deg. RS data spanned a range of local times, mostly 0-9 hours and 18-24 hours. For interests in aerocapture and precision landing, comparisons concentrated on atmospheric density. At a fixed height of 20 km, measured RS density varied by about a factor of 2.5 over the range of latitudes and Ls values observed. Evaluated at matching positions and times, average RS/Mars-GRAM density ratios were generally lf0.05, except at heights above approx. 25 km and latitudes above approx.50deg N. Average standard deviation of RS/Mars-GRAM density ratio was 6%. TES data were used covering surface to approx. 40 km, over more than a full Mars year (February, 1999 - June, 2001, just before start of Mars global dust storm). Depending on season, TES data covered latitudes 85deg S to 85deg N. Most TES data were concentrated near local times 2 hours and 14 hours. Observed average TES/Mars-GRAM density ratios were generally 1+/-0.05, except at high altitudes (15-30 km, depending on season) and high latitudes (> 45deg N), or at most altitudes in the southern hemisphere at Ls approx. 90 and 180deg). Compared to TES averages for a given latitude and season, TES data had average density standard deviation about the mean of approx. 6

  13. Mars-GRAM Applications for Mars Science Laboratory Mission Site Selection Processes

    NASA Technical Reports Server (NTRS)

    Justh, Hilary; Justus, C. G.

    2007-01-01

    An overview is presented of the Mars-Global Reference Atmospheric Model (Mars-GRAM 2005) and its new features. One important new feature is the "auxiliary profile" option, whereby a simple input file is used to replace mean atmospheric values from Mars-GRAM's conventional (General Circulation Model) climatology. An auxiliary profile can be generated from any source of data or alternate model output. Results are presented using auxiliary profiles produced from mesoscale model output (Southwest Research Institute's Mars Regional Atmospheric Modeling System (MRAMS) model and Oregon State University's Mars mesoscale model (MMM5) model) for three candidate Mars Science Laboratory (MSL) landing sites (Terby Crater, Melas Chasma, and Gale Crater). A global Thermal Emission Spectrometer (TES) database has also been generated for purposes of making 'Mars-GRAM auxiliary profiles. This data base contains averages and standard deviations of temperature, density, and thermal wind components, averaged over 5-by-5 degree latitude bins and 15 degree L(sub S) bins, for each of three Mars years of TES nadir data. Comparisons show reasonably good consistency between Mars-GRAM with low dust optical depth and both TES observed and mesoscale model simulated density at the three study sites. Mean winds differ by a more significant degree. Comparisons of mesoscale and TES standard deviations' with conventional Mars-GRAM values, show that Mars-GRAM density perturbations are somewhat conservative (larger than observed variability), while mesoscale-modeled wind variations are larger than Mars-GRAM model estimates. Input parameters rpscale (for density perturbations) and rwscale (for wind perturbations) can be used to "recalibrate" Mars-GRAM perturbation magnitudes to better replicate observed or mesoscale model variability.

  14. Utilizing Mars Global Reference Atmospheric Model (Mars-GRAM 2005) to Evaluate Entry Probe Mission Sites

    NASA Technical Reports Server (NTRS)

    Justh, Hilary L.; Justus, Carl G.

    2008-01-01

    The Mars Global Reference Atmospheric Model (Mars-GRAM 2005) is an engineering-level atmospheric model widely used for diverse mission applications. An overview is presented of Mars-GRAM 2005 and its new features. The "auxiliary profile" option is one new feature of Mars-GRAM 2005. This option uses an input file of temperature and density versus altitude to replace the mean atmospheric values from Mars-GRAM's conventional (General Circulation Model) climatology. Any source of data or alternate model output can be used to generate an auxiliary profile. Auxiliary profiles for this study were produced from mesoscale model output (Southwest Research Institute's Mars Regional Atmospheric Modeling System (MRAMS) model and Oregon State University's Mars mesoscale model (MMM5) model) and a global Thermal Emission Spectrometer (TES) database. The global TES database has been specifically generated for purposes of making Mars-GRAM auxiliary profiles. This data base contains averages and standard deviations of temperature, density, and thermal wind components, averaged over 5-by-5 degree latitude-longitude bins and 15 degree Ls bins, for each of three Mars years of TES nadir data. The Mars Science Laboratory (MSL) sites are used as a sample of how Mars-GRAM' could be a valuable tool for planning of future Mars entry probe missions. Results are presented using auxiliary profiles produced from the mesoscale model output and TES observed data for candidate MSL landing sites. Input parameters rpscale (for density perturbations) and rwscale (for wind perturbations) can be used to "recalibrate" Mars-GRAM perturbation magnitudes to better replicate observed or mesoscale model variability.

  15. Mars Aerocapture and Validation of Mars-GRAM with TES Data

    NASA Technical Reports Server (NTRS)

    Justus, C. G.; Duvall, Aleta; Keller, Vernon W.

    2005-01-01

    Mars Global Reference Atmospheric Model (Mars-GRAM) is a widely-used engineering- level Mars atmospheric model. Applications include systems design, performance analysis, and operations planning for aerobraking, entry descent and landing, and aerocapture. Typical Mars aerocapture periapsis altitudes (for systems with rigid-aeroshell heat shields) are about 50 km. This altitude is above the 0-40 km height range covered by Mars Global Surveyor Thermal Emission Spectrometer (TES) nadir observations. Recently, TES limb sounding data have been made available, spanning more than two Mars years (more than 200,000 data profiles) with altitude coverage up to about 60 km, well within the height range of interest for aerocapture. Results are presented comparing Mars-GRAM atmospheric density with densities from TES nadir and limb sounding observations. A new Mars-GRAM feature is described which allows individual TES nadir or limb profiles to be extracted from the large TES databases, and to be used as an optional replacement for standard Mars-GRAM background (climatology) conditions. For Monte-Carlo applications such as aerocapture guidance and control studies, Mars-GRAM perturbations are available using these TES profile background conditions.

  16. Validation of Mars-GRAM and Planned New Features

    NASA Technical Reports Server (NTRS)

    Justus, C. G.; Duvall, Aleta; Keller, Vernon W.

    2004-01-01

    For altitudes below 80 km, Mars Global Reference Atmospheric Model (Mars-GRAM 2001) is based on output climatology from NASA Ames Mars General Circulation Model (MGCM). At COSPAR 2002, results were presented of validation tests of Mars-GRAM versus data from Mars Global Surveyor Thermal Emission Spectrometer (TES) and Radio Science (RS) experiment. Further validation tests are presented comparing Mars- GRAM densities with those from the European Mars Climate Database (MCD), and comparing densities from both Mars-GRAM and MCD against TES observations. Throughout most of the height and latitude range of TES data (040 km and 70s to 70N), good agreement is found between atmospheric densities from Mars-GRAM and MCD. However, at the season and latitude zone for Mars Phoenix arrival and landing (Ls = 65 to 80 degrees and latitude 65 to 75N), Mars-GRAM densities are about 30 to 45 percent higher than MCD densities near 40 km altitude. Further evaluation is warranted concerning potential impact of these model differences on planning for Phoenix entry and descent. Three planned features for Mars-GRAM update are also discussed: (1) new MGCM and Thermospheric General Circulation Model data sets to be used as a revised basis for Mars-GRAM mean atmosphere, (2) a new feature to represent planetary-scale traveling waves for upper altitude density variations (such as found during Mars Odyssey aerobraking), and (3) a new model for effects of high resolution topographic slope on winds near the surface (0 to 4.5 km above MOLA topography level). Mars-GRAM slope winds will be computed from a diagnostic (algebraic) relationship based on Ye, Segal, and Pielke (1990). This approach differs from mesoscale models (such as MRAMS and Mars MM5), which use prognostic, full-physics solutions of the time- and space-dependent differential equations of motion. As such, slope winds in Mars-GRAM will be consistent with its "engineering-level" approach, and will be extremely fast and easy to evaluate

  17. Applications of Mars Global Reference Atmospheric Model (Mars-GRAM 2005) Supporting Mission Site Selection for Mars Science Laboratory

    NASA Technical Reports Server (NTRS)

    Justh, Hilary L.; Justus, Carl G.

    2008-01-01

    The Mars Global Reference Atmospheric Model (Mars-GRAM 2005) is an engineering level atmospheric model widely used for diverse mission applications. An overview is presented of Mars-GRAM 2005 and its new features. One new feature of Mars-GRAM 2005 is the 'auxiliary profile' option. In this option, an input file of temperature and density versus altitude is used to replace mean atmospheric values from Mars-GRAM's conventional (General Circulation Model) climatology. An auxiliary profile can be generated from any source of data or alternate model output. Auxiliary profiles for this study were produced from mesoscale model output (Southwest Research Institute's Mars Regional Atmospheric Modeling System (MRAMS) model and Oregon State University's Mars mesoscale model (MMM5)model) and a global Thermal Emission Spectrometer(TES) database. The global TES database has been specifically generated for purposes of making Mars-GRAM auxiliary profiles. This data base contains averages and standard deviations of temperature, density, and thermal wind components,averaged over 5-by-5 degree latitude-longitude bins and 15 degree L(s) bins, for each of three Mars years of TES nadir data. Results are presented using auxiliary profiles produced from the mesoscale model output and TES observed data for candidate Mars Science Laboratory (MSL) landing sites. Input parameters rpscale (for density perturbations) and rwscale (for wind perturbations) can be used to "recalibrate" Mars-GRAM perturbation magnitudes to better replicate observed or mesoscale model variability.

  18. Additions to Mars Global Reference Atmospheric Model (Mars-GRAM)

    NASA Technical Reports Server (NTRS)

    Justus, C. G.

    1991-01-01

    Three major additions or modifications were made to the Mars Global Reference Atmospheric Model (Mars-GRAM): (1) in addition to the interactive version, a new batch version is available, which uses NAMELIST input, and is completely modular, so that the main driver program can easily be replaced by any calling program, such as a trajectory simulation program; (2) both the interactive and batch versions now have an option for treating local-scale dust storm effects, rather than just the global-scale dust storms in the original Mars-GRAM; and (3) the Zurek wave perturbation model was added, to simulate the effects of tidal perturbations, in addition to the random (mountain wave) perturbation model of the original Mars-GRAM. A minor modification has also been made which allows heights to go below local terrain height and return realistic pressure, density, and temperature (not the surface values) as returned by the original Mars-GRAM. This feature will allow simulations of Mars rover paths which might go into local valley areas which lie below the average height of the present, rather coarse-resolution, terrain height data used by Mars-GRAM. Sample input and output of both the interactive and batch version of Mars-GRAM are presented.

  19. Additions to Mars Global Reference Atmospheric Model (MARS-GRAM)

    NASA Technical Reports Server (NTRS)

    Justus, C. G.; James, Bonnie

    1992-01-01

    Three major additions or modifications were made to the Mars Global Reference Atmospheric Model (Mars-GRAM): (1) in addition to the interactive version, a new batch version is available, which uses NAMELIST input, and is completely modular, so that the main driver program can easily be replaced by any calling program, such as a trajectory simulation program; (2) both the interactive and batch versions now have an option for treating local-scale dust storm effects, rather than just the global-scale dust storms in the original Mars-GRAM; and (3) the Zurek wave perturbation model was added, to simulate the effects of tidal perturbations, in addition to the random (mountain wave) perturbation model of the original Mars-GRAM. A minor modification was also made which allows heights to go 'below' local terrain height and return 'realistic' pressure, density, and temperature, and not the surface values, as returned by the original Mars-GRAM. This feature will allow simulations of Mars rover paths which might go into local 'valley' areas which lie below the average height of the present, rather coarse-resolution, terrain height data used by Mars-GRAM. Sample input and output of both the interactive and batch versions of Mars-GRAM are presented.

  20. Mars Global Reference Atmospheric Model (Mars-GRAM) and Database for Mission Design

    NASA Technical Reports Server (NTRS)

    Justus, C. G.; Duvall, Aleta; Johnson, D. L.

    2003-01-01

    Mars Global Reference Atmospheric Model (Mars-GRAM 2001) is an engineering-level Mars atmosphere model widely used for many Mars mission applications. From 0-80 km, it is based on NASA Ames Mars General Circulation Model, while above 80 km it is based on Mars Thermospheric General Circulation Model. Mars-GRAM 2001 and MGCM use surface topography from Mars Global Surveyor Mars Orbiting Laser Altimeter. Validation studies are described comparing Mars-GRAM with Mars Global Surveyor Radio Science and Thermal Emission Spectrometer data. RS data from 2480 profiles were used, covering latitudes 75 deg S to 72 deg N, surface to approximately 40 km, for seasons ranging from areocentric longitude of Sun (Ls) = 70-160 deg and 265-310 deg. RS data spanned a range of local times, mostly 0-9 hours and 18-24 hours. For interests in aerocapture and precision landing, comparisons concentrated on atmospheric density. At a fixed height of 20 km, RS density varied by about a factor of 2.5 over ranges of latitudes and Ls values observed. Evaluated at matching positions and times, these figures show average RSMars-GRAM density ratios were generally 1+/-)0.05, except at heights above approximately 25 km and latitudes above approximately 50 deg N. Average standard deviation of RSMars-GRAM density ratio was 6%. TES data were used covering surface to approximately 40 km, over more than a full Mars year (February, 1999 - June, 2001, just before start of a Mars global dust storm). Depending on season, TES data covered latitudes 85 deg S to 85 deg N. Most TES data were concentrated near local times 2 hours and 14 hours. Observed average TES/Mars-GRAM density ratios were generally 1+/-0.05, except at high altitudes (15-30 km, depending on season) and high latitudes (greater than 45 deg N), or at most altitudes in the southern hemisphere at Ls approximately 90 and 180 deg. Compared to TES averages for a given latitude and season, TES data had average density standard deviation about the mean of

  1. Independent Verification of Mars-GRAM 2010 with Mars Climate Sounder Data

    NASA Technical Reports Server (NTRS)

    Justh, Hilary L.; Burns, Kerry L.

    2014-01-01

    The Mars Global Reference Atmospheric Model (Mars-GRAM) is an engineering-level atmospheric model widely used for diverse mission and engineering applications. Applications of Mars-GRAM include systems design, performance analysis, and operations planning for aerobraking, entry, descent and landing, and aerocapture. Atmospheric influences on landing site selection and long-term mission conceptualization and development can also be addressed utilizing Mars-GRAM. Mars-GRAM's perturbation modeling capability is commonly used, in a Monte Carlo mode, to perform high-fidelity engineering end-to-end simulations for entry, descent, and landing. Mars-GRAM is an evolving software package resulting in improved accuracy and additional features. Mars-GRAM 2005 has been validated against Radio Science data, and both nadir and limb data from the Thermal Emission Spectrometer (TES). From the surface to 80 km altitude, Mars-GRAM is based on the NASA Ames Mars General Circulation Model (MGCM). Above 80 km, Mars-GRAM is based on the University of Michigan Mars Thermospheric General Circulation Model (MTGCM). The most recent release of Mars-GRAM 2010 includes an update to Fortran 90/95 and the addition of adjustment factors. These adjustment factors are applied to the input data from the MGCM and the MTGCM for the mapping year 0 user-controlled dust case. The adjustment factors are expressed as a function of height (z), latitude and areocentric solar longitude (Ls).

  2. Mars global reference atmosphere model (Mars-GRAM)

    NASA Technical Reports Server (NTRS)

    Justus, C. G.; James, Bonnie F.

    1992-01-01

    Mars-GRAM is an empirical model that parameterizes the temperature, pressure, density, and wind structure of the Martian atmosphere from the surface through thermospheric altitudes. In the lower atmosphere of Mars, the model is built around parameterizations of height, latitudinal, longitudinal, and seasonal variations of temperature determined from a survey of published measurements from the Mariner and Viking programs. Pressure and density are inferred from the temperature by making use of the hydrostatic and perfect gas laws relationships. For the upper atmosphere, the thermospheric model of Stewart is used. A hydrostatic interpolation routine is used to insure a smooth transition from the lower portion of the model to the Stewart thermospheric model. Other aspects of the model are discussed.

  3. Utilizing Mars Global Reference Atmospheric Model (Mars-GRAM 2005) to Evaluate Entry Probe Mission Sites

    NASA Technical Reports Server (NTRS)

    Justh, Hilary L.; Justus, C. G.

    2008-01-01

    Engineering-level atmospheric model widely used for diverse mission applications. Mars-GRAM s perturbation modeling capability is commonly used, in a Monte-Carlo mode, to perform high fidelity engineering end-to-end simulations for entry, descent, and landing (EDL)1. Traditional Mars-GRAM options for representing the mean atmosphere along entry corridors include: a) TES Mapping Years 1 and 2, with Mars-GRAM data coming from MGCM model results driven by observed TES dust optical depth; and b) TES Mapping Year 0, with user-controlled dust optical depth and Mars-GRAM data interpolated from MGCM model results driven by selected values of globally-uniform dust optical depth. From the surface to 80 km altitude, Mars-GRAM is based on NASA Ames Mars General Circulation Model (MGCM). Mars-GRAM and MGCM use surface topography from Mars Global Surveyor Mars Orbiter Laser Altimeter (MOLA), with altitudes referenced to the MOLA areoid, or constant potential surface. Mars-GRAM 2005 has been validated2 against Radio Science data, and both nadir and limb data from the Thermal Emission Spectrometer (TES)

  4. Mars Global Reference Atmospheric Model (Mars-GRAM) Version 3.8: Users Guide

    NASA Technical Reports Server (NTRS)

    Justus, C. G.; James, B. F.

    1999-01-01

    Mars Global Reference Atmospheric Model (Mars-GRAM) Version 3.8 is presented and its new features are discussed. Mars-GRAM uses new values of planetary reference ellipsoid radii, gravity term, and rotation rate (consistent with current JPL values) and includes centrifugal effects on gravity. The model now uses NASA Ames Global Circulation Model low resolution topography. Curvature corrections are applied to winds and limits based on speed of sound are applied. Altitude of the F1 ionization peak and density scale height, including effects of change of molecular weight with altitude are computed. A check is performed to disallow temperatures below CO2 sublimination. This memorandum includes instructions on obtaining Mars-GRAM source code and data files and running the program. Sample input and output are provided. An example of incorporating Mars-GRAM as an atmospheric subroutine in a trajectory code is also given.

  5. Mars Global Reference Atmospheric Model (Mars-GRAM) Version 3.8: Users Guide

    NASA Astrophysics Data System (ADS)

    Justus, C. G.; James, B. F.

    1999-05-01

    Mars Global Reference Atmospheric Model (Mars-GRAM) Version 3.8 is presented and its new features are discussed. Mars-GRAM uses new values of planetary reference ellipsoid radii, gravity term, and rotation rate (consistent with current JPL values) and includes centrifugal effects on gravity. The model now uses NASA Ames Global Circulation Model low resolution topography. Curvature corrections are applied to winds and limits based on speed of sound are applied. Altitude of the F1 ionization peak and density scale height, including effects of change of molecular weight with altitude are computed. A check is performed to disallow temperatures below CO2 sublimination. This memorandum includes instructions on obtaining Mars-GRAM source code and data files and running the program. Sample input and output are provided. An example of incorporating Mars-GRAM as an atmospheric subroutine in a trajectory code is also given.

  6. Mars Global Reference Atmospheric Model (Mars-GRAM): Release No. 2 - Overview and applications

    NASA Technical Reports Server (NTRS)

    James, B.; Johnson, D.; Tyree, L.

    1993-01-01

    The Mars Global Reference Atmospheric Model (Mars-GRAM), a science and engineering model for empirically parameterizing the temperature, pressure, density, and wind structure of the Martian atmosphere, is described with particular attention to the model's newest version, Mars-GRAM, Release No. 2 and to the improvements incorporated into the Release No. 2 model as compared with the Release No. 1 version. These improvements include (1) an addition of a new capability to simulate local-scale Martian dust storms and the growth and decay of these storms; (2) an addition of the Zurek and Haberle (1988) wave perturbation model, for simulating tidal perturbation effects; and (3) a new modular version of Mars-GRAM, for incorporation as a subroutine into other codes.

  7. Mars Global Reference Atmospheric Model 2001 Version (Mars-GRAM 2001): Users Guide

    NASA Technical Reports Server (NTRS)

    Justus, C. G.; Johnson, D. L.

    2001-01-01

    This document presents Mars Global Reference Atmospheric Model 2001 Version (Mars-GRAM 2001) and its new features. As with the previous version (mars-2000), all parameterizations fro temperature, pressure, density, and winds versus height, latitude, longitude, time of day, and season (Ls) use input data tables from NASA Ames Mars General Circulation Model (MGCM) for the surface through 80-km altitude and the University of Arizona Mars Thermospheric General Circulation Model (MTGCM) for 80 to 70 km. Mars-GRAM 2001 is based on topography from the Mars Orbiter Laser Altimeter (MOLA) and includes new MGCM data at the topographic surface. A new auxiliary program allows Mars-GRAM output to be used to compute shortwave (solar) and longwave (thermal) radiation at the surface and top of atmosphere. This memorandum includes instructions on obtaining Mars-GRAN source code and data files and for running the program. It also provides sample input and output and an example for incorporating Mars-GRAM as an atmospheric subroutine in a trajectory code.

  8. Evaluating Mars Science Laboratory Landing Sites with the Mars Global Reference Atmospheric Model (Mars-GRAM 2005)

    NASA Technical Reports Server (NTRS)

    Justh, H. L.; Justus, C. G.

    2008-01-01

    The Mars Global Reference Atmospheric Model (Mars-GRAM) is an engineering-level atmospheric model widely used for diverse mission applications. Mars-GRAM s perturbation modeling capability is commonly used, in a Monte-Carlo mode, to perform high fidelity engineering end-to-end simulations for entry, descent, and landing (EDL) [1]. From the surface to 80 km altitude, Mars-GRAM is based on the NASA Ames Mars General Circulation Model (MGCM). Mars-GRAM and MGCM use surface topography from Mars Global Surveyor Mars Orbiter Laser Altimeter (MOLA), with altitudes referenced to the MOLA areoid, or constant potential surface. Traditional Mars-GRAM options for representing the mean atmosphere along entry corridors include: (1) Thermal Emission Spectrometer (TES) mapping years 1 and 2, with Mars-GRAM data coming from NASA Ames Mars General Circulation Model (MGCM) results driven by observed TES dust optical depth or (2) TES mapping year 0, with user-controlled dust optical depth and Mars-GRAM data interpolated from MGCM model results driven by selected values of globally-uniform dust optical depth. Mars-GRAM 2005 has been validated [2] against Radio Science data, and both nadir and limb data from TES [3]. There are several new features included in Mars-GRAM 2005. The first is the option to use input data sets from MGCM model runs that were designed to closely simulate conditions observed during the first two years of TES observations at Mars. The TES Year 1 option includes values from April 1999 through January 2001. The TES Year 2 option includes values from February 2001 through December 2002. The second new feature is the option to read and use any auxiliary profile of temperature and density versus altitude. In exercising the auxiliary profile Mars-GRAM option, values from the auxiliary profile replace data from the original MGCM databases. Some examples of auxiliary profiles include data from TES nadir or limb observations and Mars mesoscale model output at a particular

  9. Mars Global Reference Atmospheric Model (Mars-GRAM 3.34): Programmer's Guide

    NASA Technical Reports Server (NTRS)

    Justus, C. G.; James, Bonnie F.; Johnson, Dale L.

    1996-01-01

    This is a programmer's guide for the Mars Global Reference Atmospheric Model (Mars-GRAM 3.34). Included are a brief history and review of the model since its origin in 1988 and a technical discussion of recent additions and modifications. Examples of how to run both the interactive and batch (subroutine) forms are presented. Instructions are provided on how to customize output of the model for various parameters of the Mars atmosphere. Detailed descriptions are given of the main driver programs, subroutines, and associated computational methods. Lists and descriptions include input, output, and local variables in the programs. These descriptions give a summary of program steps and 'map' of calling relationships among the subroutines. Definitions are provided for the variables passed between subroutines through common lists. Explanations are provided for all diagnostic and progress messages generated during execution of the program. A brief outline of future plans for Mars-GRAM is also presented.

  10. Mars Global Reference Atmospheric Model 2000 Version (Mars-GRAM 2000): Users Guide

    NASA Technical Reports Server (NTRS)

    Justus, C. G.; James, B. F.

    2000-01-01

    This report presents Mars Global Reference Atmospheric Model 2000 Version (Mars-GRAM 2000) and its new features. All parameterizations for temperature, pressure, density, and winds versus height, latitude, longitude, time of day, and L(sub s) have been replaced by input data tables from NASA Ames Mars General Circulation Model (MGCM) for the surface through 80-km altitude and the University of Arizona Mars Thermospheric General Circulation Model (MTGCM) for 80 to 170 km. A modified Stewart thermospheric model is still used for higher altitudes and for dependence on solar activity. "Climate factors" to tune for agreement with GCM data are no longer needed. Adjustment of exospheric temperature is still an option. Consistent with observations from Mars Global Surveyor, a new longitude-dependent wave model is included with user input to specify waves having 1 to 3 wavelengths around the planet. A simplified perturbation model has been substituted for the earlier one. An input switch allows users to select either East or West longitude positive. This memorandum includes instructions on obtaining Mars-GRAM source code and data files and for running the program. It also provides sample input and output and an example for incorporating Mars-GRAM as an atmospheric subroutine in a trajectory code.

  11. Mars Global Reference Atmospheric Model (Mars-GRAM 2005) Applications for Mars Science Laboratory Mission Site Selection Processes

    NASA Technical Reports Server (NTRS)

    Justh, H. L.; Justus, C. G.

    2007-01-01

    The new Mars-GRAM auxiliary profile capability, using data from TES observations, mesoscale model output, or other sources, allows a potentially higher fidelity representation of the atmosphere, and a more accurate way of estimating inherent uncertainty in atmospheric density and winds. Figure 3 indicates that, with nominal value rpscale=1, Mars-GRAM perturbations would tend to overestimate observed or mesoscale-modeled variability. To better represent TES and mesoscale model density perturbations, rpscale values as low as about 0.4 could be used. Some trajectory model implementations of Mars-GRAM allow the user to dynamically change rpscale and rwscale values with altitude. Figure 4 shows that an mscale value of about 1.2 would better replicate wind standard deviations from MRAMS or MMM5 simulations at the Gale, Terby, or Melas sites. By adjusting the rpscale and rwscale values in Mars-GRAM based on figures such as Figure 3 and 4, we can provide more accurate end-to-end simulations for EDL at the candidate MSL landing sites.

  12. A Revised Thermosphere for the Mars Global Reference Atmospheric Model (Mars-GRAM Version 3.4)

    NASA Technical Reports Server (NTRS)

    Justus, C. G.; Johnson, D. L.; James, B. F.

    1996-01-01

    This report describes the newly-revised model thermosphere for the Mars Global Reference Atmospheric Model (Mars-GRAM, Version 3.4). It also provides descriptions of other changes made to the program since publication of the programmer's guide for Mars-GRAM Version 3.34. The original Mars-GRAM model thermosphere was based on the global-mean model of Stewart. The revised thermosphere is based largely on parameterizations derived from output data from the three-dimensional Mars Thermospheric Global Circulation Model (MTGCM). The new thermospheric model includes revised dependence on the 10.7 cm solar flux for the global means of exospheric temperature, temperature of the base of the thermosphere, and scale height for the thermospheric temperature variations, as well as revised dependence on orbital position for global mean height of the base of the thermosphere. Other features of the new thermospheric model are: (1) realistic variations of temperature and density with latitude and time of day, (2) more realistic wind magnitudes, based on improved estimates of horizontal pressure gradients, and (3) allowance for user-input adjustments to the model values for mean exospheric temperature and for height and temperature at the base of the thermosphere. Other new features of Mars-GRAM 3.4 include: (1) allowance for user-input values of climatic adjustment factors for temperature profiles from the surface to 75 km, and (2) a revised method for computing the sub-solar longitude position in the 'ORBIT' subroutine.

  13. Surveillance Metrics Sensitivity Study

    SciTech Connect

    Bierbaum, R; Hamada, M; Robertson, A

    2011-11-01

    In September of 2009, a Tri-Lab team was formed to develop a set of metrics relating to the NNSA nuclear weapon surveillance program. The purpose of the metrics was to develop a more quantitative and/or qualitative metric(s) describing the results of realized or non-realized surveillance activities on our confidence in reporting reliability and assessing the stockpile. As a part of this effort, a statistical sub-team investigated various techniques and developed a complementary set of statistical metrics that could serve as a foundation for characterizing aspects of meeting the surveillance program objectives. The metrics are a combination of tolerance limit calculations and power calculations, intending to answer level-of-confidence type questions with respect to the ability to detect certain undesirable behaviors (catastrophic defects, margin insufficiency defects, and deviations from a model). Note that the metrics are not intended to gauge product performance but instead the adequacy of surveillance. This report gives a short description of four metrics types that were explored and the results of a sensitivity study conducted to investigate their behavior for various inputs. The results of the sensitivity study can be used to set the risk parameters that specify the level of stockpile problem that the surveillance program should be addressing.

  14. Surveillance metrics sensitivity study.

    SciTech Connect

    Hamada, Michael S.; Bierbaum, Rene Lynn; Robertson, Alix A.

    2011-09-01

    In September of 2009, a Tri-Lab team was formed to develop a set of metrics relating to the NNSA nuclear weapon surveillance program. The purpose of the metrics was to develop a more quantitative and/or qualitative metric(s) describing the results of realized or non-realized surveillance activities on our confidence in reporting reliability and assessing the stockpile. As a part of this effort, a statistical sub-team investigated various techniques and developed a complementary set of statistical metrics that could serve as a foundation for characterizing aspects of meeting the surveillance program objectives. The metrics are a combination of tolerance limit calculations and power calculations, intending to answer level-of-confidence type questions with respect to the ability to detect certain undesirable behaviors (catastrophic defects, margin insufficiency defects, and deviations from a model). Note that the metrics are not intended to gauge product performance but instead the adequacy of surveillance. This report gives a short description of four metrics types that were explored and the results of a sensitivity study conducted to investigate their behavior for various inputs. The results of the sensitivity study can be used to set the risk parameters that specify the level of stockpile problem that the surveillance program should be addressing.

  15. Sensitized Liquid Hydrazine Detonation Studies

    NASA Technical Reports Server (NTRS)

    Rathgeber, K. A.; Keddy, C. P.; Bunker, R. L.

    1999-01-01

    Vapor-phase hydrazine (N2H4) is known to be very sensitive to detonation while liquid hydrazine is very insensitive to detonation, theoretically requiring extremely high pressures to induce initiation. A review of literature on solid and liquid explosives shows that when pure explosive substances are infiltrated with gas cavities, voids, and/or different phase contaminants, the energy or shock pressure necessary to induce detonation can decrease by an order of magnitude. Tests were conducted with liquid hydrazine in a modified card-gap configuration. Sensitization was attempted by bubbling helium gas through and/or suspending ceramic microspheres in the liquid. The hydrazine was subjected to the shock pressure from a 2 lb (0.9 kg) Composition C-4 explosive charge. The hydrazine was contained in a 4 in. (10.2 cm) diameter stainless steel cylinder with a 122 in(sup 3) (2 L) volume and sealed with a polyethylene cap. Blast pressures from the events were recorded by 63 high speed pressure transducers located on three radial legs extending from 4 to 115 ft (1.2 to 35.1 in) from ground zero. Comparison of the neat hydrazine and water baseline tests with the "sensitized" hydrazine tests indicates the liquid hydrazine did not detonate under these conditions.

  16. Icing Encounter Duration Sensitivity Study

    NASA Technical Reports Server (NTRS)

    Addy, Harold E., Jr.; Lee, Sam

    2011-01-01

    This paper describes a study performed to investigate how aerodynamic performance degradation progresses with time throughout an exposure to icing conditions. It is one of the first documented studies of the effects of ice contamination on aerodynamic performance at various points in time throughout an icing encounter. Both a 1.5 and 6 ft chord, two-dimensional, NACA-23012 airfoils were subjected to icing conditions in the NASA Icing Research Tunnel for varying lengths of time. At the end of each run, lift, drag, and pitching moment measurements were made. Measurements with the 1.5 ft chord model showed that maximum lift and pitching moment degraded more rapidly early in the exposure and degraded more slowly as time progressed. Drag for the 1.5 ft chord model degraded more linearly with time, although drag for very short exposure durations was slightly higher than expected. Only drag measurements were made with the 6 ft chord airfoil. Here, drag for the long exposures was higher than expected. Novel comparison of drag measurements versus an icing scaling parameter, accumulation parameter times collection efficiency was used to compare the data from the two different size model. The comparisons provided a means of assessing the level of fidelity needed for accurate icing simulation.

  17. Lunar magnetic permeability studies and magnetometer sensitivity

    NASA Technical Reports Server (NTRS)

    King, J. H.; Ness, N. F.

    1977-01-01

    A regression of quiet magnetic field components simultaneously measured by the two Explorer 35 magnetometers reveals uncertainties in effective sensitivity factors of up to a few percent in one or both of these instruments. Given this, the validity of previous lunar permeability studies based on Explorer 35/ALSEP regressions, wherein inferences are drawn from regression line slopes differing from unity by the order of one percent, is called into question. We emphasize the need to critically address the question of small deviations in magnetometer sensitivity factors from nominal values as a part of any two-magnetometer lunar permeability study.

  18. Advanced protein crystal growth programmatic sensitivity study

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The purpose of this study is to define the costs of various APCG (Advanced Protein Crystal Growth) program options and to determine the parameters which, if changed, impact the costs and goals of the programs and to what extent. This was accomplished by developing and evaluating several alternate programmatic scenarios for the microgravity Advanced Protein Crystal Growth program transitioning from the present shuttle activity to the man tended Space Station to the permanently manned Space Station. These scenarios include selected variations in such sensitivity parameters as development and operational costs, schedules, technology issues, and crystal growth methods. This final report provides information that will aid in planning the Advanced Protein Crystal Growth Program.

  19. Turbulence sensitivity study in the IBI region

    NASA Astrophysics Data System (ADS)

    Reffray, G.; Chanut, J.; Cailleau, S.; Levier, B.

    2009-04-01

    In the framework of building a high resolution operational system covering the IBI area (Iberian Biscay Irish), a turbulence sensitivity study is carried out to improve the results of the NEMO model. This is particularly important on the shelf where the mixing is very strong and mainly induced by the intense tidal currents. The investigated work is to test some parameterizations more sophisticated (for ex: stability functions from Canuto (2001) or surface boundary conditions including wave effects from Mellor and Blumberg 2003) and to note if the biases with the observations are reduced as expected. To make this numerical study easier, the Generic Length Scale model (Umlauf and Burchard, 2003) has been implemented. The choice of the dissipation rate as turbulent scale has been done because this closure is well documented and contrary to the Mellor-Yamada turbulent scale, this equation does not need any wall function to provide results physically relevant.

  20. Ramp Compression Experiments - a Sensitivity Study

    SciTech Connect

    Bastea, M; Reisman, D

    2007-02-26

    We present the first sensitivity study of the material isentropes extracted from ramp compression experiments. We perform hydrodynamic simulations of representative experimental geometries associated with ramp compression experiments and discuss the major factors determining the accuracy of the equation of state information extracted from such data. In conclusion, we analyzed both qualitatively and quantitatively the major experimental factors that determine the accuracy of equations of state extracted from ramp compression experiments. Since in actual experiments essentially all the effects discussed here will compound, factoring out individual signatures and magnitudes, as done in the present work, is especially important. This study should provide some guidance for the effective design and analysis of ramp compression experiments, as well as for further improvements of ramp generators performance.

  1. Chemical feedbacks in climate sensitivity studies

    NASA Astrophysics Data System (ADS)

    Dietmüller, Simone; Ponater, Michael; Sausen, Robert

    2013-04-01

    Interactively coupled climate chemistry models extend the number of feedback mechanisms in climate change simulations by allowing a variation of several radiatively actice chemical tracers that are prescribed in conventional climate models. Different perturbation experiments including chemical feedbacks were performed using the chemistry-climate model system EMAC coupled to the mixed layer ocean model MLO. The influence of the chemical feedbacks O3, CH4 and N2O on climate response and climate sensitivity is quantified for a series of CO2-perturbation simulations: Equilibrium climate sensitivity is dampened, if chemical feedbacks are included. In case of a CO2 doubling simulation chemical feedbacks decrease climate sensitivity by -3.6% and in case of a 4*CO2 simulation by -8.1%. Analysis of the chemical feedbacks reveals, that the negative feedback of ozone, mainly the feedback of stratospheric ozone, is responsible for this dampening. The radiative feedbacks of CH4 and N2O are negligible, mainly because the model system does not allow interactive emission feedbacks at the Earth's surface for these gases. The feedback of physical parameters is significantly modified by the presence of chemical feedbacks. In case of the CO2-perturbation experiments the negative stratospheric ozone feedback is accompanied by a negative stratospheric H2O feedback change of the same order of magnitude. So the dampening effect of the direct O3 radiative feedback is enhanced. A non-linearity in the damping is found with increasing CO2 concentrations. Reasons are the nonlinear feedbacks of ozone, temperature, and stratospheric water vapor. Additional 6*CO2 simulations with and without chemical feedbacks included show, that the presence of chemic feedbacks helps to prevent a runaway greenhouse effect, as the O3 distribution can react to the upward shift of the tropopause. Also experiments driven by anthropogenic NOx- and CO-emissions were performed, where chemically active trace gases act

  2. Sensitivity Studies for Assimilated Ozone Profiles

    NASA Technical Reports Server (NTRS)

    Stajner, Ivanka; Winslow, Nathan; Wargan, Krzysztof; Rood, Richard; Pawson, Steven

    2002-01-01

    An ozone data assimilation system at the NASA/Goddard Data Assimilation Office (DAO) produces three-dimensional global ozone fields. They are obtained by assimilating ozone retrieved from the Solar Backscatter UltraViolet/2 (SBUV/2) instrument and the Earth Probe Total Ozone Mapping Spectrometer (EP TOMS) measurements into an off-line parameterized chemistry and transport model. In this talk we focus on the quality of lower stratospheric assimilated ozone profiles. Ozone in the lower stratosphere plays a key role in the forcing of climate. A biased ozone field in this region will adversely impact calculations of the stratosphere-troposphere exchange and, when used as a first guess in retrievals, the values determined from satellite observations. The SBUV/2 ozone data have a coarse vertical resolution with increased uncertainty below the ozone maximum, and TOMS provides only total ozone columns. Thus, the assimilated ozone profiles in the lower stratosphere are only weakly constrained by the incoming SBUV and TOMS data. Consequently, the assimilated ozone distribution should be sensitive to changes in inputs to the statistical analysis scheme. We investigate the sensitivity of assimilated ozone profiles to changes in a variety of system inputs: TOMS and SBUV/2 data selection, forecast and observations error covariance models, inclusion or omission of a parameterized chemistry model, and different versions of DAO assimilated wind fields used to drive the transport model. Comparisons of assimilated ozone fields with independent observations, primarily ozone sondes, are used to determine the impact of each of these changes.

  3. HCIT Broadband Contrast Performance Sensitivity Studies

    NASA Technical Reports Server (NTRS)

    Sidick, Erkin; Shaklan, Stuart; Balasubramanian, Kunjithapatham

    2012-01-01

    One of the important milestones of the TPF Coronagraph project is to demonstrate the ability to predict the performance sensitivities of the system at levels consistent with exo-planet detection requirement. We want to gain some general understanding about the potentials and the limitations of the current single-Deformable-Mirror (DM) High-contrast imaging testbed (HCIT) system through modeling and simulations. Specifically, we want to understand the effects of some common errors on the EFC-based control of e-field over a half dark-hole region and broadband contrast. Investigated errors include: (1) Absorbing particles on a flat-mirror (2) Defects on the Occulter surface (3) Dead actuators on the DM. We also investigated the effects of control bandwidth on the broadband contrast. We used a MACOS-based simulation algorithm which (1) combines a ray trace, diffraction model, & a broadband wavefront control algorithm (2) is capable of performing full three-dimensional near-field diffraction analysis

  4. Tropical cirrus cloud radiative forcing: Sensitivity studies

    SciTech Connect

    Jensen, E.J.; Kinne, S.; Toon, O.B.

    1994-09-01

    We have performed one dimensional radiative transfer calculations to evaluate the impact of cirrus clouds on the tropical radiation budget. We investigate the sensitivity of solar and infrared fluxes to cloud optical depth, particle size distributions, and cloud height. If the observed solar cloud forcing in excess of 100 W/sq m is to be attributed to cirrus anvils alone, then the optical depth of these anvils must be at least 5 (assuming 50% cloud cover and an ice crystal effective radius of 15 microns). The net radiative forcing of cirrus near the tropical tropopause is positive (heating) for cloud optical depths less than about 16 and negative (cooling) for larger optical depths. If cirrus clouds alone are responsible for the equal and opposite shortwave and longwave cloud forcing in excess of 100 W/sq m observed by Earth Radiation Budget Experiment (ERBE), then the cirrus must typically take the form of deep, optically thick clouds with relatively small particles (radii of 10-20 microns) and cloud-tops well below the tropopause. The maintenance of this balance on monthly time scales can be attributed to a variety of correlations: The cloud cover of optically thick cirrus or thin cirrus overlying low-level stratus clouds could vary; or cirrus anvil height cloud increase along with a decrease in the ice crystal effective radius and an increase in optical depth. It would be of great interest to determine observationally which of these correlations is responsible for the observed lack of variation in cloud forcing.

  5. A study of eigenvalue sensitivity for hydrodynamic stability operators

    NASA Technical Reports Server (NTRS)

    Schmid, Peter J.; Henningson, Dan S.; Khorrami, Mehdi R.; Malik, Mujeeb R.

    1993-01-01

    The eigenvalue sensitivity for hydrodynamic stability operators is investigated. Classical matrix perturbation techniques as well as the concept of epsilon-pseudospectra are applied to show that parts of the spectrum are highly sensitive to small perturbations. Applications are drawn from incompressible plane Couette flow, trailing line vortex flow, and compressible Blasius boundary-layer flow. Parameter studies indicate a monotonically increasing effect of the Reynolds number on the sensitivity. The phenomenon of eigenvalue sensitivity is due to the nonnormality of the operators and their discrete matrix analogs and may be associated with large transient growth of the corresponding initial value problem.

  6. Measuring chemical sensitivity prevalence: a questionnaire for population studies.

    PubMed Central

    Kipen, H M; Hallman, W; Kelly-McNeil, K; Fiedler, N

    1995-01-01

    Because no information exists on the prevalence of chemical sensitivity syndromes such as multiple chemical sensitivities, a questionnaire for use in population studies was developed and tested to assess the presence or absence of chemical sensitivity. Seven hundred five individuals attending clinics answered a questionnaire asking whether each of 122 common substances caused symptoms. Results showed that patients with multiple chemical sensitivities and asthma had average total scores that were significantly different from each other and from those of each of the other diagnostic categories. Higher total scores were also reported by female patients. The instrument described here may facilitate meaningful prevalence studies of multiple chemical sensitivities. It will also allow study of chemically induced symptoms in other conditions such as asthma. PMID:7702128

  7. Sensitivity Study for Long Term Reliability

    NASA Technical Reports Server (NTRS)

    White, Allan L.

    2008-01-01

    This paper illustrates using Markov models to establish system and maintenance requirements for small electronic controllers where the goal is a high probability of continuous service for a long period of time. The system and maintenance items considered are quality of components, various degrees of simple redundancy, redundancy with reconfiguration, diagnostic levels, periodic maintenance, and preventive maintenance. Markov models permit a quantitative investigation with comparison and contrast. An element of special interest is the use of conditional probability to study the combination of imperfect diagnostics and periodic maintenance.

  8. Grid Sensitivity Study for Slat Noise Simulations

    NASA Technical Reports Server (NTRS)

    Lockard, David P.; Choudhari, Meelan M.; Buning, Pieter G.

    2014-01-01

    The slat noise from the 30P/30N high-lift system is being investigated through computational fluid dynamics simulations in conjunction with a Ffowcs Williams-Hawkings acoustics solver. Many previous simulations have been performed for the configuration, and the case was introduced as a new category for the Second AIAA workshop on Benchmark problems for Airframe Noise Configurations (BANC-II). However, the cost of the simulations has restricted the study of grid resolution effects to a baseline grid and coarser meshes. In the present study, two different approaches are being used to investigate the effect of finer resolution of near-field unsteady structures. First, a standard grid refinement by a factor of two is used, and the calculations are performed by using the same CFL3D solver employed in the majority of the previous simulations. Second, the OVERFLOW code is applied to the baseline grid, but with a 5th-order upwind spatial discretization as compared with the second-order discretization used in the CFL3D simulations. In general, the fine grid CFL3D simulation and OVERFLOW calculation are in very good agreement and exhibit the lowest levels of both surface pressure fluctuations and radiated noise. Although the smaller scales resolved by these simulations increase the velocity fluctuation levels, they appear to mitigate the influence of the larger scales on the surface pressure. These new simulations are used to investigate the influence of the grid on unsteady high-lift simulations and to gain a better understanding of the physics responsible for the noise generation and radiation.

  9. HCIT Broadband Contrast Performance Sensitivity Studies

    NASA Technical Reports Server (NTRS)

    Sidick, Erkin; Shaklan, Stuart; Balasubramanian, Kunjithapatham

    2012-01-01

    The High Contrast Imaging Testbed (HCIT) at the Jet Propulsion Laboratory employs a broadband wavefront correction algorithm called Electric Field Conjugation (EFC) to obtain the required 10-10 contrast. This algorithm works with one deformable mirror (DM) to estimate the electric-field to be controlled, and with one or multiple DM's to create a "darkhole" in a predefined region of the image plane where terrestrial planets would be found. We have investigated the effects of absorbing dust particles on a flat optic, absorbing spots on the occulting mask, dead actuators on the DM, and the effects of control bandwidth on the efficiency of the EFC algorithm in a Lyot coronagraph configuration. The structural design of the optical system as well as the parameters of various optical elements used in the analysis is drawn from those of the HCIT system that have been implemented with one DM. The simulation takes into account the surface errors of various optical elements. Results of some of these studies have been verified by actual measurements.

  10. Intercultural Sensitivity through Short-Term Study Abroad

    ERIC Educational Resources Information Center

    Bloom, Melanie; Miranda, Arturo

    2015-01-01

    One of the foremost-cited rationales for study abroad during college is the development of a global perspective and intercultural sensitivity. Although this argument is mentioned frequently in promotional materials for study abroad, it has not yet been backed by research based on the outcomes of students' study abroad experiences. As more…

  11. Sensitivity study for s process nucleosynthesis in AGB stars

    NASA Astrophysics Data System (ADS)

    Koloczek, A.; Thomas, B.; Glorius, J.; Plag, R.; Pignatari, M.; Reifarth, R.; Ritter, C.; Schmidt, S.; Sonnabend, K.

    2016-03-01

    In this paper we present a large-scale sensitivity study of reaction rates in the main component of the s process. The aim of this study is to identify all rates, which have a global effect on the s process abundance distribution and the three most important rates for the production of each isotope. We have performed a sensitivity study on the radiative 13C-pocket and on the convective thermal pulse, sites of the s process in AGB stars. We identified 22 rates, which have the highest impact on the s-process abundances in AGB stars.

  12. Sensitivity study on durability variables of marine concrete structures

    NASA Astrophysics Data System (ADS)

    Zhou, Xin'gang; Li, Kefei

    2013-06-01

    In order to study the influence of parameters on durability of marine concrete structures, the parameter's sensitivity analysis was studied in this paper. With the Fick's 2nd law of diffusion and the deterministic sensitivity analysis method (DSA), the sensitivity factors of apparent surface chloride content, apparent chloride diffusion coefficient and its time dependent attenuation factor were analyzed. The results of the analysis show that the impact of design variables on concrete durability was different. The values of sensitivity factor of chloride diffusion coefficient and its time dependent attenuation factor were higher than others. Relative less error in chloride diffusion coefficient and its time dependent attenuation coefficient induces a bigger error in concrete durability design and life prediction. According to probability sensitivity analysis (PSA), the influence of mean value and variance of concrete durability design variables on the durability failure probability was studied. The results of the study provide quantitative measures of the importance of concrete durability design and life prediction variables. It was concluded that the chloride diffusion coefficient and its time dependent attenuation factor have more influence on the reliability of marine concrete structural durability. In durability design and life prediction of marine concrete structures, it was very important to reduce the measure and statistic error of durability design variables.

  13. Aspartame Sensitivity? A Double Blind Randomised Crossover Study

    PubMed Central

    Sathyapalan, Thozhukat; Thatcher, Natalie J.; Hammersley, Richard; Rigby, Alan S.; Pechlivanis, Alexandros; Gooderham, Nigel J.; Holmes, Elaine; le Roux, Carel W.; Atkin, Stephen L.; Courts, Fraser

    2015-01-01

    Background Aspartame is a commonly used intense artificial sweetener, being approximately 200 times sweeter than sucrose. There have been concerns over aspartame since approval in the 1980s including a large anecdotal database reporting severe symptoms. The objective of this study was to compare the acute symptom effects of aspartame to a control preparation. Methods This was a double-blind randomized cross over study conducted in a clinical research unit in United Kingdom. Forty-eight individual who has self reported sensitivity to aspartame were compared to 48 age and gender matched aspartame non-sensitive individuals. They were given aspartame (100mg)-containing or control snack bars randomly at least 7 days apart. The main outcome measures were acute effects of aspartame measured using repeated ratings of 14 symptoms, biochemistry and metabonomics. Results Aspartame sensitive and non-sensitive participants differed psychologically at baseline in handling feelings and perceived stress. Sensitive participants had higher triglycerides (2.05 ± 1.44 vs. 1.26 ± 0.84mmol/L; p value 0.008) and lower HDL-C (1.16 ± 0.34 vs. 1.35 ± 0.54 mmol/L; p value 0.04), reflected in 1H NMR serum analysis that showed differences in the baseline lipid content between the two groups. Urine metabonomic studies showed no significant differences. None of the rated symptoms differed between aspartame and control bars, or between sensitive and control participants. However, aspartame sensitive participants rated more symptoms particularly in the first test session, whether this was placebo or control. Aspartame and control bars affected GLP-1, GIP, tyrosine and phenylalanine levels equally in both aspartame sensitive and non-sensitive subjects. Conclusion Using a comprehensive battery of psychological tests, biochemistry and state of the art metabonomics there was no evidence of any acute adverse responses to aspartame. This independent study gives reassurance to both regulatory bodies

  14. Comparative study of normal and sensitive skin aerobic bacterial populations

    PubMed Central

    Hillion, Mélanie; Mijouin, Lily; Jaouen, Thomas; Barreau, Magalie; Meunier, Pauline; Lefeuvre, Luc; Lati, Elian; Chevalier, Sylvie; Feuilloley, Marc G J

    2013-01-01

    The purpose of this study was to investigate if the sensitive skin syndrome, a frequent skin disorder characterized by abnormal painful reactions to environmental factors in the absence of visible inflammatory response, could be linked to a modification in the skin bacterial population. A total of 1706 bacterial isolates was collected at the levels of the forehead, cheekbone, inner elbow, and lower area of the scapula on the skin of normal and sensitive skin syndrome-suffering volunteers of both sexes and of different ages. Among these isolates, 21 strains were randomly selected to validate in a first step the Matrix-Assisted Laser Desorption/Ionization (MALDI)-Biotyper process as an efficient identification tool at the group and genus levels, by comparison to API® strips and 16S ribosomal RNA gene sequencing identification techniques. In a second step, identification of the skin microbiota isolates by the MALDI-Biotyper tool allowed to pinpoint some differences in terms of bacterial diversity with regard to the collection area, and the volunteer's age and gender. Finally, comparison of the skin microbiota from normal and sensitive skin syndrome-suffering volunteers pointed out gender-related variations but no detectable correlation between a phylum, a genus or a dominant bacterial species and the sensitive skin phenotype. This study reveals that there is no dysbiosis of aerobic cultivable bacteria associated with the sensitive skin syndrome and further demonstrates that the MALDI-Biotyper is a powerful technique that can be efficiently employed to the study of cultivable human skin bacteria. To our knowledge, this is the first study focusing on bacteria in the sensitive skin syndrome. These results are of potential importance for pharmaceutical and cosmetic industries, which are looking for new strategies to treat this multiparametric disorder. PMID:24151137

  15. Comparative study of normal and sensitive skin aerobic bacterial populations.

    PubMed

    Hillion, Mélanie; Mijouin, Lily; Jaouen, Thomas; Barreau, Magalie; Meunier, Pauline; Lefeuvre, Luc; Lati, Elian; Chevalier, Sylvie; Feuilloley, Marc G J

    2013-12-01

    The purpose of this study was to investigate if the sensitive skin syndrome, a frequent skin disorder characterized by abnormal painful reactions to environmental factors in the absence of visible inflammatory response, could be linked to a modification in the skin bacterial population. A total of 1706 bacterial isolates was collected at the levels of the forehead, cheekbone, inner elbow, and lower area of the scapula on the skin of normal and sensitive skin syndrome-suffering volunteers of both sexes and of different ages. Among these isolates, 21 strains were randomly selected to validate in a first step the Matrix-Assisted Laser Desorption/Ionization (MALDI)-Biotyper process as an efficient identification tool at the group and genus levels, by comparison to API(®) strips and 16S ribosomal RNA gene sequencing identification techniques. In a second step, identification of the skin microbiota isolates by the MALDI-Biotyper tool allowed to pinpoint some differences in terms of bacterial diversity with regard to the collection area, and the volunteer's age and gender. Finally, comparison of the skin microbiota from normal and sensitive skin syndrome-suffering volunteers pointed out gender-related variations but no detectable correlation between a phylum, a genus or a dominant bacterial species and the sensitive skin phenotype. This study reveals that there is no dysbiosis of aerobic cultivable bacteria associated with the sensitive skin syndrome and further demonstrates that the MALDI-Biotyper is a powerful technique that can be efficiently employed to the study of cultivable human skin bacteria. To our knowledge, this is the first study focusing on bacteria in the sensitive skin syndrome. These results are of potential importance for pharmaceutical and cosmetic industries, which are looking for new strategies to treat this multiparametric disorder. PMID:24151137

  16. Sensitivity and uncertainty studies of the CRAC2 computer code.

    PubMed

    Kocher, D C; Ward, R C; Killough, G G; Dunning, D E; Hicks, B B; Hosker, R P; Ku, J Y; Rao, K S

    1987-12-01

    We have studied the sensitivity of health impacts from nuclear reactor accidents, as predicted by the CRAC2 computer code, to the following sources of uncertainty: (1) the model for plume rise, (2) the model for wet deposition, (3) the meteorological bin-sampling procedure for selecting weather sequences with rain, (4) the dose conversion factors for inhalation as affected by uncertainties in the particle size of the carrier aerosol and the clearance rates of radionuclides from the respiratory tract, (5) the weathering half-time for external ground-surface exposure, and (6) the transfer coefficients for terrestrial foodchain pathways. Predicted health impacts usually showed little sensitivity to use of an alternative plume-rise model or a modified rain-bin structure in bin-sampling. Health impacts often were quite sensitive to use of an alternative wet-deposition model in single-trial runs with rain during plume passage, but were less sensitive to the model in bin-sampling runs. Uncertainties in the inhalation dose conversion factors had important effects on early injuries in single-trial runs. Latent cancer fatalities were moderately sensitive to uncertainties in the weathering half-time for ground-surface exposure, but showed little sensitivity to the transfer coefficients for terrestrial foodchain pathways. Sensitivities of CRAC2 predictions to uncertainties in the models and parameters also depended on the magnitude of the source term, and some of the effects on early health effects were comparable to those that were due only to selection of different sets of weather sequences in bin-sampling. PMID:3444936

  17. Anxiety Sensitivity and Panic Attacks: A 1-Year Longitudinal Study

    ERIC Educational Resources Information Center

    Li, Wen; Zinbarg, Richard E.

    2007-01-01

    The hypothesis that anxiety sensitivity (AS) is a risk factor for panic genesis has obtained compelling support, but the clinical/practical importance of AS in panic genesis has been questioned. In addition, the association between panic experience and AS increase has not been clearly demonstrated. Through this 1-year longitudinal study among…

  18. Ethical problems and moral sensitivity in physiotherapy: a descriptive study.

    PubMed

    Kulju, Kati; Suhonen, Riitta; Leino-Kilpi, Helena

    2013-08-01

    This study identified and described ethical problems encountered by physiotherapists in their practice and physiotherapists' moral sensitivity in ethical situations. A questionnaire-based survey was constructed to identify ethical problems, and the Moral Sensitivity Questionnaire Revised version was used to measure moral sensitivity. Physiotherapists (n = 116) working in public health services responded to the questionnaire. Based on the results, most of the physiotherapists encounter ethical problems weekly. They concern mainly financial considerations, equality and justice, professionalism, unethical conduct of physiotherapists or other professions and patients' self-determination. The dimension of moral strength was emphasised in physiotherapists' self-evaluations of their moral sensitivity. As a conclusion, ethical problems do occur not only at individual level but also at organisational and society level. Physiotherapists seem to have moral strength for speaking on behalf of the patient. Scarce resources make them feel insufficient but much could still be done to provide quality care in co-operation with other health-care professionals. PMID:23329778

  19. Shuttle filter study. Volume 2: Contaminant generation and sensitivity studies

    NASA Technical Reports Server (NTRS)

    1974-01-01

    Contaminant generation studies were conducted at the component level using two different methods, radioactive tracer technique and gravimetric analysis test procedure. Both of these were reduced to practice during this program. In the first of these methods, radioactively tagged components typical of those used in spacecraft were studied to determine their contaminant generation characteristics under simulated operating conditions. Because the purpose of the work was: (1) to determine the types and quantities of contaminants generated; and (2) to evaluate improved monitoring and detection schemes, no attempt was made to evaluate or qualify specific components. The components used in this test program were therefore not flight hardware items. Some of them had been used in previous tests; some were obsolete; one was an experimental device. In addition to the component tests, various materials of interest to contaminant and filtration studies were irradiated and evaluated for use as autotracer materials. These included test dusts, plastics, valve seat materials, and bearing cage materials.

  20. Pain sensitivity and opioid analgesia: a pharmacogenomic twin study.

    PubMed

    Angst, Martin S; Phillips, Nicholas G; Drover, David R; Tingle, Martha; Ray, Amrita; Swan, Gary E; Lazzeroni, Laura C; Clark, J David

    2012-07-01

    Opioids are the cornerstone medication for the management of moderate to severe pain. Unfortunately, vast inter-individual differences in dose requirements complicate their effective and safe clinical use. Mechanisms underlying such differences are incompletely understood, are likely multifactorial, and include genetic and environmental contributions. While accumulating evidence suggests that variants of several genes account for some of the observed response variance, the relative contribution of these factors remains unknown. This study used a twin paradigm to provide a global estimate of the genetic and environmental contributions to inter-individual differences in pain sensitivity and analgesic opioid effects. Eighty one monozygotic and 31 dizygotic twin pairs successfully underwent a computer-controlled infusion with the μ-opioid agonist alfentanil in a single occasion, randomized, double-blind and placebo-controlled study design. Pain sensitivity and analgesic effects were assessed with experimental heat and cold pressor pain models along with important covariates including demographic factors, depression, anxiety, and sleep quality. Significant heritability was detected for cold pressor pain tolerance and opioid-mediated elevations in heat and cold pressor pain thresholds. Genetic effects accounted for 12-60% of the observed response variance. Significant familial effects accounting for 24-32% of observed variance were detected for heat and cold pressor pain thresholds and opioid-mediated elevation in cold pressor pain tolerance. Significant covariates included age, gender, race, education, and anxiety. Results provide a strong rationale for more detailed molecular genetic studies to elucidate mechanisms underlying inter-individual differences in pain sensitivity and analgesic opioid responses. Such studies will require careful consideration of the studied pain phenotype. PMID:22444188

  1. Contamination sensitivity of typical mirror coatings - A parametric study

    NASA Technical Reports Server (NTRS)

    Osantowski, J. F.

    1983-01-01

    Contamination budgeting for space optical systems basically starts at understanding the sensitivity of component performance, e.g. mirror reflectance, window transmittance, etc., to surface deposits. To evaluate contamination sensitivity for mirror coatings, eight types representative of those used in the vacuum ultraviolet, visible, and infrared were modeled assuming that the contaminant is uniformly deposited on the mirror surface. Parametric studies over a range of complex refractive indices combined with an examination of optical data available for several organic materials suggested division of the contaminant layer index into three categories, N = 1.5 + 0.1i, N = 1.5 + 0.5i, and N = 1.5 + 2.0i. Contaminant thickness sensitivity curves were then calculated for each of the selected mirror coatings. For comparative purposes, critical thicknesses for each type were extracted, assuming a reflectance loss of 10 percent was allowable. Critical thicknesses ranged from about 10 A to 1000 A depending on the specifics of coating design and spectral region.

  2. Sensitivity study of a dynamic thermodynamic sea ice model

    SciTech Connect

    Holland, D.M.; Mysak, L.A.; Manak, D.K. )

    1993-02-15

    A numerical simulation of the seasonal sea ice cover in the Arctic Ocean and the Greenland, Iceland, and Norwegian seas is presented. The sea ice model is extracted from Oberhuber's (1990) coupled sea ice-mixed layer-isopycnal general circulation model and is written in spherical coordinates. The advantage of such a model over previous sea ice models is that it can be easily coupled to either global atmospheric or ocean general circulation models written in spherical coordinates. In this model, the thermodynamics are a modification of that of Parkinson and Washington, while the dynamics use the full Hibler viscous-plastic rheology. Monthly thermodynamic and dynamic forcing fields for the atmosphere and ocean are specified. The simulations of the seasonal cycle of ice thickness, compactness, and velocity, for a control set of parameters, compare favorably with the known seasonal characteristics of these fields. A sensitivity study of the control simulation of the seasonal sea ice cover is presented. The sensitivity runs are carried out under three different themes, namely, numerical conditions, parameter values, and physical processes. This last theme refers to experiments in which physical processes are either newly added or completely removed from the model. Approximately 80 sensitivity runs have been performed in which a change from the control run environment has been implemented. Comparisons have been made between the control run and a particular sensitivity run based on time series of the seasonal cycle of the domain-averaged ice thickness, compactness, areal coverage, and kinetic energy. In addition, spatially varying fields of ice thickness, compactness, velocity, and surface temperature for each season are presented for selected experiments. A brief description and discussion of the more interesting experiments are presented. The simulation of the seasonal cycle of Arctic sea ice cover is shown to be robust. 31 refs., 20 figs., 5 tabs.

  3. Mass sensitivity studies for an inductively driven railgun

    NASA Astrophysics Data System (ADS)

    Scanlon, J. J., III; Young, A. F.

    1991-01-01

    Those areas which result in substantial system mass reductions for an HPG (homopolar generator) driven EML (electromagnetic launcher) are identified. Sensitivity studies are performed by varying launch mass, peak acceleration, launcher efficiency, inductance gradient, injection velocity, barrel mass per unit length, fuel tankage and pump estimates, and component energy and power densities. Two major contributors to the system mass are the allowed number of shots per barrel versus the number required for the mission, and the barrel length. The effects of component performance parameters, such as friction coefficient, injection velocity, ablation coefficient, rail resistivity, armature voltage, peak acceleration, and inductance gradient on these two areas, are addressed.

  4. Physics sensitivity studies of Fine-Grained Tracker

    SciTech Connect

    Tian, Xinchun; Mishra, Sanjib R.; Petti, Roberto; Hongyue, Duyang

    2015-10-15

    The reference design of the near detector for the LBNE experiment is a high-resolution Fine-Grained Tracker (FGT). We performed sensitivity studies – critical to constraining the systematics in oscillation searches – of measurements of (1) the absolute neutrino flux, (2) neutrino-nucleon quasi-elastic (QE) and (3) resonance (Res) interactions. In QE and Res emphasis is laid in identifying in situ measurables that help constrain nuclear effects such as initial state pair wise correlations and final state interactions.

  5. Sensitivity Studies of Sea Ice Formation In The Kara Sea

    NASA Astrophysics Data System (ADS)

    Hübner, U.; Harms, I.; Backhaus, J. O.

    Sea ice formation is an important process in Arctic shelf seas because it determines environmental conditions in the whole Arctic, in particular at the coasts. Arctic shelf seas receive large amounts of freshwater which has a significant impact on ice forma- tion and which could be affected by climate change. In order to study the direct and indirect influence of river runoff on sea ice formation, a high resolution baroclinic 3-d circulation and sea ice model is applied to the Kara Sea. The model is forced with realistic atmospheric winds, surface heat fluxes, river runoff and tides. A vertical adaptive grid is used which provides high resolution in critical areas such as shallow estuaries, slopes or topographic obstacles. The surface following boundary layer is resolved uniformly in 4 m intervals in order to resolve the strong vertical stratification. The simulated melting rates are sensitive to the penetration depth of shortwave radia- tion into the water column. Peak runoff rates in the Kara Sea in spring might exceed 100.000 m3/s which causes high suspended loads in the water column and reduces the shortwave penetration depth considerably compared to ambient Arctic waters. As a result, coastal sea surface temperatures rise and ice melting is significantly enhanced. Our sensitivity studies show, that the indirect influence of river runoff on ice melting could play an important role in future studies on climate variability in the Arctic.

  6. Developing a temperature sensitive tool for studying spin dissipation

    NASA Astrophysics Data System (ADS)

    Wickey, Kurtis Jon

    Measuring the thermodynamic properties of nanoscale structures is becoming increasingly important as heterostructures and devices shrink in size. For example, recent discoveries of spin thermal effects such as spin Seebeck and spin Peltier show that thermal gradients can manipulate spin systems and vice versa. However, the relevant interactions occur within a spin diffusion length of a spin active interface, making study of these spin thermal effects challenging. In addition, recent ferromagnetic resonance studies of spatially confined nanomagnets have shown unique magnon modes in arrays and lines which may give rise to unique magnon-phonon interactions. In this case, the small volume of magnetic material presents a challenge to measurement and as a result the bulk of the work is done on arrays with measurements of the magnetization of individual particles possible through various microscopies but limited access to thermal properties. As a result, tools capable of measuring the thermal properties of nanoscale structures are required to fully explore this emerging science. One approach to addressing this challenge is the use of microscale suspended platforms that maximize their sensitivity to these spin thermal interactions through thermal isolation from their surroundings. Combining this thermal decoupling with sensitive thermometry allows for the measurement of nanojoule heat accumulations, such as those resulting from the small heat flows associated with spin transport and spin relaxation. As these heat flows may manifest themselves in a variety of spin-thermal effects, the development of measurement platforms that can be tailored to optimize their sensitivity to specific thermal measurements is essential. To address these needs, I have fabricated thermally isolated platforms using a unique focused ion beam (FIB) machining that allow for flexible geometries as well as a wide choice of material systems. The thermal characteristics of these platforms were

  7. Sensitivity studies for a space-based methane lidar mission

    NASA Astrophysics Data System (ADS)

    Kiemle, C.; Quatrevalet, M.; Ehret, G.; Amediek, A.; Fix, A.; Wirth, M.

    2011-10-01

    Methane is the third most important greenhouse gas in the atmosphere after water vapour and carbon dioxide. A major handicap to quantify the emissions at the Earth's surface in order to better understand biosphere-atmosphere exchange processes and potential climate feedbacks is the lack of accurate and global observations of methane. Space-based integrated path differential absorption (IPDA) lidar has potential to fill this gap, and a Methane Remote Lidar Mission (MERLIN) on a small satellite in polar orbit was proposed by DLR and CNES in the frame of a German-French climate monitoring initiative. System simulations are used to identify key performance parameters and to find an advantageous instrument configuration, given the environmental, technological, and budget constraints. The sensitivity studies use representative averages of the atmospheric and surface state to estimate the measurement precision, i.e. the random uncertainty due to instrument noise. Key performance parameters for MERLIN are average laser power, telescope size, orbit height, surface reflectance, and detector noise. A modest-size lidar instrument with 0.45 W average laser power and 0.55 m telescope diameter on a 506 km orbit could provide 50-km averaged methane column measurement along the sub-satellite track with a precision of about 1% over vegetation. The use of a methane absorption trough at 1.65 μm improves the near-surface measurement sensitivity and vastly relaxes the wavelength stability requirement that was identified as one of the major technological risks in the pre-phase A studies for A-SCOPE, a space-based IPDA lidar for carbon dioxide at the European Space Agency. Minimal humidity and temperature sensitivity at this wavelength position will enable accurate measurements in tropical wetlands, key regions with largely uncertain methane emissions. In contrast to actual passive remote sensors, measurements in Polar Regions will be possible and biases due to aerosol layers and thin

  8. Sensitivity studies for a space-based methane lidar mission

    NASA Astrophysics Data System (ADS)

    Kiemle, C.; Quatrevalet, M.; Ehret, G.; Amediek, A.; Fix, A.; Wirth, M.

    2011-06-01

    Methane is the third most important greenhouse gas in the atmosphere after water vapour and carbon dioxide. A major handicap to quantify the emissions at the Earth's surface in order to better understand biosphere-atmosphere exchange processes and potential climate feedbacks is the lack of accurate and global observations of methane. Space-based integrated path differential absorption (IPDA) lidar has potential to fill this gap, and a Methane Remote Lidar Mission (MERLIN) on a small satellite in Polar orbit was proposed by DLR and CNES in the frame of a German-French climate monitoring initiative. System simulations are used to identify key performance parameters and to find an advantageous instrument configuration, given the environmental, technological, and budget constraints. The sensitivity studies use representative averages of the atmospheric and surface state to estimate the measurement precision, i.e. the random uncertainty due to instrument noise. Key performance parameters for MERLIN are average laser power, telescope size, orbit height, surface reflectance, and detector noise. A modest-size lidar instrument with 0.45 W average laser power and 0.55 m telescope diameter on a 506 km orbit could provide 50-km averaged methane column measurement along the sub-satellite track with a precision of about 1 % over vegetation. The use of a methane absorption trough at 1.65 μm improves the near-surface measurement sensitivity and vastly relaxes the wavelength stability requirement that was identified as one of the major technological risks in the pre-phase A studies for A-SCOPE, a space-based IPDA lidar for carbon dioxide at the European Space Agency. Minimal humidity and temperature sensitivity at this wavelength position will enable accurate measurements in tropical wetlands, key regions with largely uncertain methane emissions. In contrast to actual passive remote sensors, measurements in Polar Regions will be possible and biases due to aerosol layers and thin

  9. Computational studies of quantum dot sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Kolesov, Grigory

    This thesis presents a computational study of quantum dot (QD) sensitized solar cells. First part deals with the non-equilibrium many-body theory or non-equilibrium Green's function (NEGF) theory. In this approach I study electron dynamics in the quantum-dot sensitized solar cell subjected to time-dependent fields. NEGF theory, because it does not impose any conditions on a perturbation, is the fundamental one to describe ultrafast processes in small, strongly correlated systems and/or in strong fields. In this research I do not only perform analytical derivation, but also design and implement spectral numerical solution for the resulting complex system of partial integrodifferential equations. This numerical solution yielded an order of magnitude speedup over the methods used previously in the field. The forth chapter of this thesis deals with calculation of optical properties and the ground state configuration of Zn2SnO4 (ZTO). ZTO is used by experimentalists in UW to grow nanorods which are then sensitized by QDs. ZTO is a challenging material for computational analysis because of its inverse spinel structure; thus it has an immense number of configurations matching the X-ray diffraction experiments. I've applied a cluster expansion method and have found the ground state configuration and phase diagram for ZTO. Calculations of optical properties of ground state bulk ZTO were done with a recently developed DFT functional. The optical band gap obtained in these calculations matched the experimental value. The last chapter describes development of the general simulator for interdigitated array electrodes. The application of this simulation together with the experiments may lead to understanding of reaction parameters and mechanisms important for development of electrochemical solar cells.

  10. Sensitivity analysis in multiple imputation in effectiveness studies of psychotherapy

    PubMed Central

    Crameri, Aureliano; von Wyl, Agnes; Koemeda, Margit; Schulthess, Peter; Tschuschke, Volker

    2015-01-01

    The importance of preventing and treating incomplete data in effectiveness studies is nowadays emphasized. However, most of the publications focus on randomized clinical trials (RCT). One flexible technique for statistical inference with missing data is multiple imputation (MI). Since methods such as MI rely on the assumption of missing data being at random (MAR), a sensitivity analysis for testing the robustness against departures from this assumption is required. In this paper we present a sensitivity analysis technique based on posterior predictive checking, which takes into consideration the concept of clinical significance used in the evaluation of intra-individual changes. We demonstrate the possibilities this technique can offer with the example of irregular longitudinal data collected with the Outcome Questionnaire-45 (OQ-45) and the Helping Alliance Questionnaire (HAQ) in a sample of 260 outpatients. The sensitivity analysis can be used to (1) quantify the degree of bias introduced by missing not at random data (MNAR) in a worst reasonable case scenario, (2) compare the performance of different analysis methods for dealing with missing data, or (3) detect the influence of possible violations to the model assumptions (e.g., lack of normality). Moreover, our analysis showed that ratings from the patient's and therapist's version of the HAQ could significantly improve the predictive value of the routine outcome monitoring based on the OQ-45. Since analysis dropouts always occur, repeated measurements with the OQ-45 and the HAQ analyzed with MI are useful to improve the accuracy of outcome estimates in quality assurance assessments and non-randomized effectiveness studies in the field of outpatient psychotherapy. PMID:26283989

  11. Sensitivity studies for the weak r process: neutron capture rates

    SciTech Connect

    Surman, R.; Mumpower, M.; Sinclair, R.; Jones, K. L.; Hix, W. R.; McLaughlin, G. C.

    2014-04-15

    Rapid neutron capture nucleosynthesis involves thousands of nuclear species far from stability, whose nuclear properties need to be understood in order to accurately predict nucleosynthetic outcomes. Recently sensitivity studies have provided a deeper understanding of how the r process proceeds and have identified pieces of nuclear data of interest for further experimental or theoretical study. A key result of these studies has been to point out the importance of individual neutron capture rates in setting the final r-process abundance pattern for a ‘main’ (A ∼ 130 peak and above) r process. Here we examine neutron capture in the context of a ‘weak’ r process that forms primarily the A ∼ 80 r-process abundance peak. We identify the astrophysical conditions required to produce this peak region through weak r-processing and point out the neutron capture rates that most strongly influence the final abundance pattern.

  12. Verification, Validation and Sensitivity Studies in Computational Biomechanics

    PubMed Central

    Anderson, Andrew E.; Ellis, Benjamin J.; Weiss, Jeffrey A.

    2012-01-01

    Computational techniques and software for the analysis of problems in mechanics have naturally moved from their origins in the traditional engineering disciplines to the study of cell, tissue and organ biomechanics. Increasingly complex models have been developed to describe and predict the mechanical behavior of such biological systems. While the availability of advanced computational tools has led to exciting research advances in the field, the utility of these models is often the subject of criticism due to inadequate model verification and validation. The objective of this review is to present the concepts of verification, validation and sensitivity studies with regard to the construction, analysis and interpretation of models in computational biomechanics. Specific examples from the field are discussed. It is hoped that this review will serve as a guide to the use of verification and validation principles in the field of computational biomechanics, thereby improving the peer acceptance of studies that use computational modeling techniques. PMID:17558646

  13. STUDIES ON THE SENSITIZATION OF ANIMALS WITH SIMPLE CHEMICAL COMPOUNDS

    PubMed Central

    Landsteiner, K.; Di Somma, A. A.

    1938-01-01

    With the view of making new types of chemicals accessible for investigations on drug hypersensitiveness, methods have been devised for sensitizing animals with diazomethane and mustard oil, two non-aromatic compounds. Guinea pigs have been sensitized to diazomethane, a substance of high reactivity and known to cause severe allergic effects in man. With the second substance, allylisothiocyanate, likewise capable of forming conjugates with substances in the animal body, sensitization effects have been obtained in man and in hogs. Sensitization in human beings was successful with one out of six individuals treated. The observations indicate species and individual differences as regards the ability to become sensitized to various chemical compounds. PMID:19870801

  14. Oral Toxicity Study and Skin Sensitization Test of a Cricket.

    PubMed

    Ryu, Hyeon Yeol; Lee, Somin; Ahn, Kyu Sup; Kim, Hye Jin; Lee, Sang Sik; Ko, Hyuk Ju; Lee, Jin Kyu; Cho, Myung-Haing; Ahn, Mi Young; Kim, Eun Mi; Lim, Jeong Ho; Song, Kyung Seuk

    2016-04-01

    Crickets have been attracting considerable interest in the field of nutrition and toxicology due to the global exhaustion of food resulting from a growing population. The cricket is normally eaten in several countries after roasting, similar to the grasshopper; however, safety evaluation data on cricket powder is limited. Here, we performed general toxicity studies of cricket powder including a single, 2-week repeated dose range evaluation test, a 13-week repeated oral dose toxicity test in Sprague-Dawley rats, a single oral dose toxicity test in Beagle dogs, and a skin sensitization test in guinea pigs following the Organization for Economic Cooperation and Development test guidelines 406 and 408 in addition to Good Laboratory Practice. To investigate the NOAEL and target organs of cricket powder, Sprague-Dawley rats were allocated to 4 groups: vehicle control, 1,250 mg/kg, 2,500 mg/kg, 5,000 mg/kg dose test groups and cricket powder was administered over 13 weeks after single dose and dose range finding studies in rats based on the results of the single oral administration toxicity study in rats and Beagle dogs. The results of the study showed that the NOAEL of cricket powder was over 5,000 mg/kg for both sexes of rats without adverse effects in a 13-week repeated oral toxicity study and there was no skin hypersensitivity reaction. Therefore, our results reveal that crickets can be widely used as a new substitute food or nutrient resource. PMID:27123167

  15. Oral Toxicity Study and Skin Sensitization Test of a Cricket

    PubMed Central

    Ryu, Hyeon Yeol; Lee, Somin; Ahn, Kyu Sup; Kim, Hye Jin; Lee, Sang Sik; Ko, Hyuk Ju; Lee, Jin Kyu; Cho, Myung-Haing; Ahn, Mi Young; Kim, Eun Mi; Lim, Jeong Ho; Song, Kyung Seuk

    2016-01-01

    Crickets have been attracting considerable interest in the field of nutrition and toxicology due to the global exhaustion of food resulting from a growing population. The cricket is normally eaten in several countries after roasting, similar to the grasshopper; however, safety evaluation data on cricket powder is limited. Here, we performed general toxicity studies of cricket powder including a single, 2-week repeated dose range evaluation test, a 13-week repeated oral dose toxicity test in Sprague-Dawley rats, a single oral dose toxicity test in Beagle dogs, and a skin sensitization test in guinea pigs following the Organization for Economic Cooperation and Development test guidelines 406 and 408 in addition to Good Laboratory Practice. To investigate the NOAEL and target organs of cricket powder, Sprague-Dawley rats were allocated to 4 groups: vehicle control, 1,250 mg/kg, 2,500 mg/kg, 5,000 mg/kg dose test groups and cricket powder was administered over 13 weeks after single dose and dose range finding studies in rats based on the results of the single oral administration toxicity study in rats and Beagle dogs. The results of the study showed that the NOAEL of cricket powder was over 5,000 mg/kg for both sexes of rats without adverse effects in a 13-week repeated oral toxicity study and there was no skin hypersensitivity reaction. Therefore, our results reveal that crickets can be widely used as a new substitute food or nutrient resource. PMID:27123167

  16. Parameter Sensitivity Study of the Wall Interference Correction System (WICS)

    NASA Technical Reports Server (NTRS)

    Walker, Eric L.; Everhart, Joel L.; Iyer, Venkit

    2001-01-01

    An off-line version of the Wall Interference Correction System (WICS) has been implemented for the "NASA Langley National Transonic Facility. The correction capability is currently restricted to corrections for solid wall interference in the model pitch plane for Mach numbers, less than 0.45 due to a limitation in tunnel calibration data. A study to assess output sensitivity to the aerodynamic parameters of Reynolds number and Mach number was conducted on this code to further ensure quality during the correction process. In addition, this paper includes all investigation into possible correction due to a semispan test technique using a non metric standoff and all improvement to the standard data rejection algorithm.

  17. Mass sensitivity studies for an inductively driven railgun

    SciTech Connect

    Scanlon, J.J. ); Young, A.F. )

    1991-01-01

    One of the primary system constructs for an Electromagnetic Launcher (EML) System consists of a homopolar generator (HPG) driven by a hot hydrogen multi-stage turbine/nuclear reactor. The HPG is used to charge an inductive energy store. A key evaluation criterion for determining the viability of an EML is system mass. The objective of this paper is to identify those areas which result in substantial system mass reductions for an HPG driven EML. Sensitivity studies are performed by varying launch mass peak acceleration, launcher efficiency, inductance gradient (L{prime}), injection velocity, barrel mass per unit length, fuel tankage and pump estimates, and component energy and power densities. Two major contributors to the system mass are the allowed number of shots per barrel versus the number required for the mission, and the barrel length.

  18. A New Approach for Coupled GCM Sensitivity Studies

    NASA Astrophysics Data System (ADS)

    Kirtman, B. P.; Duane, G. S.

    2011-12-01

    A new multi-model approach for coupled GCM sensitivity studies is presented. The purpose of the sensitivity experiments is to understand why two different coupled models have such large differences in their respective climate simulations. In the application presented here, the differences between the coupled models using the Center for Ocean-Land-Atmosphere Studies (COLA) and the National Center for Atmospheric Research (NCAR) atmospheric general circulation models (AGCMs) are examined. The intent is to isolate which component of the air-sea fluxes is most responsible for the differences between the coupled models and for the errors in their respective coupled simulations. The procedure is to simultaneously couple the two different atmospheric component models to a single ocean general circulation model (OGCM), in this case the Modular Ocean Model (MOM) developed at the Geophysical Fluid Dynamics Laboratory (GFDL). Each atmospheric component model experiences the same SST produced by the OGCM, but the OGCM is simultaneously coupled to both AGCMs using a cross coupling strategy. In the first experiment, the OGCM is coupled to the heat and fresh water flux from the NCAR AGCM (Community Atmospheric Model; CAM) and the momentum flux from the COLA AGCM. Both AGCMs feel the same SST. In the second experiment, the OGCM is coupled to the heat and fresh water flux from the COLA AGCM and the momentum flux from the CAM AGCM. Again, both atmospheric component models experience the same SST. By comparing these two experimental simulations with control simulations where only one AGCM is used, it is possible to argue which of the flux components are most responsible for the differences in the simulations and their respective errors. Based on these sensitivity experiments we conclude that the tropical ocean warm bias in the COLA coupled model is due to errors in the heat flux, and that the erroneous westward shift in the tropical Pacific cold tongue minimum in the NCAR model is

  19. Dynamics within alkylsiloxane SAMs studied by sensitive dielectric spectroscopy

    NASA Astrophysics Data System (ADS)

    Scott, Mary; Stevens, Derrick; Bochinski, Jason; Clarke, Laura

    2009-03-01

    Self assembled monolayers (SAMs) are a ubiquitous tool in modern research and their static structure has been extensively studied. Fewer investigations have addressed dynamics within these systems; however, such motions within SAMs will affect surface properties such as friction and blocking ability (permeability). In this study, sensitive, dielectric spectroscopy over a broad temperature range (4-400 K) has been employed to study relaxations within planar alkylsiloxane SAMs[1] . Highly disordered SAMs of varying density were grown by vapor deposition. Two dielectric relaxations were observed. The first, a polyethylene-like relaxation similar to that previously reported in phase-segregated alkyl side-chain polymers, is observed for all films with alkyl chains containing four or more carbons. This is an interacting or glassy relaxation. The second motion, which is observable only at high film densities, is a local mode, which follows an Arrhenius dependence on temperature, and has been previously assigned to a sub-chain rotation. [1] M.C. Scott, D.R. Stevens, J.R. Bochinski, L.I. Clarke, ACS Nano. DOI: 10.1021/nn800543j.

  20. Implications of recent multimodel attribution studies for climate sensitivity

    NASA Astrophysics Data System (ADS)

    Lewis, Nicholas

    2016-03-01

    Equilibrium climate sensitivity (ECS) is inferred from estimates of instrumental-period warming attributable solely to greenhouse gases (AW), as derived in two recent multi-model detection and attribution (D&A) studies that apply optimal fingerprint methods with high spatial resolution to 3D global climate model simulations. This approach minimises the key uncertainty regarding aerosol forcing without relying on low-dimensional models. The "observed" AW distributions from the D&A studies together with an observationally-based estimate of effective planetary heat capacity (EHC) are applied as observational constraints in (AW, EHC) space. By varying two key parameters—ECS and effective ocean diffusivity—in an energy balance model forced solely by greenhouse gases, an invertible map from the bivariate model parameter space to (AW, EHC) space is generated. Inversion of the constrained (AW, EHC) space through a transformation of variables allows unique recovery of the observationally-constrained joint distribution for the two model parameters, from which the marginal distribution of ECS can readily be derived. The method is extended to provide estimated distributions for transient climate response (TCR). The AW distributions from the two D&A studies produce almost identical results. Combining the two sets of results provides best estimates (5-95 % ranges) of 1.66 (0.7-3.2) K for ECS and 1.37 (0.65-2.2) K for TCR, in line with those from several recent studies based on observed warming from all causes but with tighter uncertainty ranges than for some of those studies. Almost identical results are obtained from application of an alternative profile likelihood statistical methodology.

  1. Study of Nonclassical Fields in Phase-Sensitive Reservoirs

    NASA Technical Reports Server (NTRS)

    Kim, Myung Shik; Imoto, Nobuyuki

    1996-01-01

    We show that the reservoir influence can be modeled by an infinite array of beam splitters. The superposition of the input fields in the beam splitter is discussed with the convolution laws for their quasiprobabilities. We derive the Fokker-Planck equation for the cavity field coupled with a phase-sensitive reservoir using the convolution law. We also analyze the amplification in the phase-sensitive reservoir with use of the modified beam splitter model. We show the similarities and differences between the dissipation and amplification models. We show that a super-Poissonian input field cannot become sub-Poissonian by the phase-sensitive amplification.

  2. Sensitivity study of SMILES-2 for chemical species

    NASA Astrophysics Data System (ADS)

    Suzuki, Makoto; Manago, Naohiro; Ozeki, Hiroyuki; Ochiai, Satoshi; Baron, Philippe

    2015-10-01

    Sensitivity studies of temperature and chemical species (Observed by ISS/JEM/SMILES: O3, HCl, ClO, HO2, BrO, HNO3, CH3CN, and Not observed by SMILES: Temperature, H2O, N2O, NO2, NO, CH3Cl, CO, H2CO, OH and O-atom) was carried out for the SMILES-2 proposal, a sub-mm and THz observation of limb emission from space over the spectral region from 400 GHz to 2.5 THz. Tentative but optimal candidate of frequency bands to cover these species was selected with 3 SIS (Superconductor-Insulator-Superconductor) mixers; SIS-1 (485-489 GHz + 523-527 GHz), SIS-2 (623-627 GHz + 648-652 GHz), SIS-3 (557 GHz + 576.3 GHz) and 2 HEB (Hot Electron Bolometer); HEB-1 (1.8 THz OH) and HEB-2 (2.06 THz O-atom). Temperature can be retrieved with 1 K precision and 1 km vertical resolution from 15 to 120 km. Other chemical species also showed very high single scan precision (random error) comparable to statistical standard error of previous satellite measurements.

  3. Sensitivity studies for the main r process: nuclear masses

    SciTech Connect

    Aprahamian, A.; Mumpower, M.; Bentley, I.; Surman, R.

    2014-04-15

    The site of the rapid neutron capture process (r process) is one of the open challenges in all of physics today. The r process is thought to be responsible for the creation of more than half of all elements beyond iron. The scientific challenges to understanding the origin of the heavy elements beyond iron lie in both the uncertainties associated with astrophysical conditions that are needed to allow an r process to occur and a vast lack of knowledge about the properties of nuclei far from stability. One way is to disentangle the nuclear and astrophysical components of the question. On the nuclear physics side, there is great global competition to access and measure the most exotic nuclei that existing facilities can reach, while simultaneously building new, more powerful accelerators to make even more exotic nuclei. On the astrophysics side, various astrophysical scenarios for the production of the heaviest elements have been proposed but open questions remain. This paper reports on a sensitivity study of the r process to determine the most crucial nuclear masses to measure using an r-process simulation code, several mass models (FRDM, Duflo-Zuker, and HFB-21), and three potential astrophysical scenarios.

  4. STUDIES ON THE SENSITIZATION OF ANIMALS WITH SIMPLE CHEMICAL COMPOUNDS

    PubMed Central

    Maguire, Henry C.; Chase, Merrill W.

    1972-01-01

    A method of establishing regular and intense sensitivity to picric acid is described, based upon an initial sensitization by a "split-adjuvant" technique in which the intradermal injection of mycobacteria in paraffin oil precedes or follows the administration of allergen to the same sites. When subsequent contact applications of picric acid are later made, the degree of sensitivity rises in steps such that reactivity occurs in tests made with low concentrations of picric acid, in the range of 0.06–0.006% but varying somewhat from one experiment to another. This heightening of picric acid reactivity represents an anamnestic response in the area of delayed hypersensitivity. The characteristics of contact reactions to the weak allergen, picric acid, differ from those encountered with covalently binding haptens, PCI and DNCB. A slow evolution from an initial micropapular reaction to full reaction requires about 3 days, leading often to a micaceous scale, with histological evidence of vesiculation even while the reaction is still feeble, and to an infiltrate containing a significant number of polymorphonuclear leukocytes. Substitution of an emulsion of picric acid in complete Freund's adjuvant as a priming experience proved to be much less efficient. The split-adjuvant technique offers a general plan for sensitizing with weak allergens. Indeed, technically, sensitization can be acquired even when, for priming, the allergen is applied topically over intradermal depots of mycobacteria in paraffin oil. Compatibility between sensitizer and adjuvant is not required. PMID:5060294

  5. Enhanced reward sensitivity and decreased loss sensitivity in Internet addicts: an fMRI study during a guessing task.

    PubMed

    Dong, Guangheng; Huang, Jie; Du, Xiaoxia

    2011-11-01

    As the world's fastest growing "addiction", Internet addiction should be studied to unravel the potential heterogeneity. The present study is set to examine reward and punishment processing in Internet addicts as compared to healthy controls while they subjectively experience monetary gain and loss during the performance of a guessing task. The results showed that Internet addicts associated with increased activation in orbitofrontal cortex in gain trials and decreased anterior cingulate activation in loss trials than normal controls. The results suggested that Internet addicts have enhanced reward sensitivity and decreased loss sensitivity than normal comparisons. PMID:21764067

  6. Fundamental studies of nanoarchitectured dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Yang, Zhenzhen

    2011-12-01

    Dye-sensitized solar cells (DSSCs) are a promising candidate for next-generation photovoltaic panels due to their low cost, easy fabrication processes and relatively high efficiency. Despite the considerable effort on the advancement of DSSCs, the efficiency of DSSCs has been stalled for nearly two decades due to the complex interplay among various DSSC parameters. Particularly, in a conventional DSSC, a thicker semiconductor photovoltaic (PV) layer, i.e., a dye-sensitized TiO2 nanoparticle layer, is required to accommodate more light-induced charge separation centers to enhance light harvesting efficiency. However, a thicker PV layer concurrently increases the charge transport distance in the PV layer; so the system suffers from more charge recombination, leading to significant deterioration in charge collection efficiency. The conflicting demands on the thickness of PV layer by these two critical elementary photoelectrochemical processes becomes a fundamental limitation for further advancement in DSSCs and limits the choice of redox mediators and electrode materials in DSSCs. Hence, the focus of this dissertation research work is to systematically explore a transformative way to fundamentally resolve the conflicting interplay between light harvesting and charge transport. First, our strategy is to allocate part of the roughness factor to the collecting anode instead of imparting all the roughness factors onto the semiconductor PV layer attached to the anode. As a proof of concept, we first synthesized and characterized a microscopically rough Zn collecting anode, on which ZnO nanotips are grown. For the same surface roughness factor, the length of the ZnO nanotips supported on such a rough Zn anode can be much shorter than that of the ZnO nanowires supported on a planar anode. Our Zn-microtip|ZnO-nanotip DSSCs exhibit enhanced fill factor, Voc and Jsc. The investigation of kinetics indicates that the electron collection time is much faster than the electron

  7. Paleozoic ice sheet inception; a study of paleogeographic sensitivity

    NASA Astrophysics Data System (ADS)

    Horton, D. E.; Poulsen, C. J.; Torsvik, T. H.

    2011-12-01

    Large-scale continental glaciation is thought to have been episodic throughout the Paleozoic era. Evidence of short-lived glaciation in the Ordovician, a period of questionable glaciation in the Devonian, and extensive glaciation in the Permo-Carboniferous are variously supported by the geologic record. The climatic conditions that allowed Earth to descend into icehouse conditions during these periods are not well understood. Traditionally, Paleozoic glaciation was thought to be driven by the drift of continents over the austral pole, yet a myriad of other factors play a role in global mean temperatures and the ability of an icehouse climate to initiate. In this sensitivity study we utilize a coupled GCM-ice sheet-biome model in conjunction with updated paleogeographic reconstructions to examine ice sheet initiation at 30 million year time slices throughout the Paleozoic. Each time slice is subjected to an ice-favorable orbital alignment and a range of atmospheric pCO2 concentrations in an effort to determine the influence of continent distribution and greenhouse gas concentration on ice sheet initiation. Our modeling results demonstrate that both continental configuration and atmospheric pCO2 concentration play a significant role in ice sheet initiation, ice sheet areal extent, and ice sheet volume. Our results indicate that the geographic configurations most conducive to continental glaciation occurred from the mid-Devonian to the early Carboniferous, a result that is inconsistent with the geologic record and suggests that continental drift wasn't the sole driving force behind the occurrence of Paleozoic ice ages.

  8. Sensitivity study on hydraulic well testing inversion using simulated annealing

    SciTech Connect

    Nakao, Shinsuke; Najita, J.; Karasaki, Kenzi

    1997-11-01

    For environmental remediation, management of nuclear waste disposal, or geothermal reservoir engineering, it is very important to evaluate the permeabilities, spacing, and sizes of the subsurface fractures which control ground water flow. Cluster variable aperture (CVA) simulated annealing has been used as an inversion technique to construct fluid flow models of fractured formations based on transient pressure data from hydraulic tests. A two-dimensional fracture network system is represented as a filled regular lattice of fracture elements. The algorithm iteratively changes an aperture of cluster of fracture elements, which are chosen randomly from a list of discrete apertures, to improve the match to observed pressure transients. The size of the clusters is held constant throughout the iterations. Sensitivity studies using simple fracture models with eight wells show that, in general, it is necessary to conduct interference tests using at least three different wells as pumping well in order to reconstruct the fracture network with a transmissivity contrast of one order of magnitude, particularly when the cluster size is not known a priori. Because hydraulic inversion is inherently non-unique, it is important to utilize additional information. The authors investigated the relationship between the scale of heterogeneity and the optimum cluster size (and its shape) to enhance the reliability and convergence of the inversion. It appears that the cluster size corresponding to about 20--40 % of the practical range of the spatial correlation is optimal. Inversion results of the Raymond test site data are also presented and the practical range of spatial correlation is evaluated to be about 5--10 m from the optimal cluster size in the inversion.

  9. The simulated Indian monsoon: A GCM sensitivity study

    NASA Technical Reports Server (NTRS)

    Fennessy, M. J.; Kinter, J. L., III; Kirtman, B.; Marx, L.; Nigam, S.; Schneider, E.; Shukla, J.; Straus, D.; Vernekar, A.; Xue, Y.

    1994-01-01

    A series of sensitivity experiments are conducted in an attempt to understand and correct deficiencies in the simulation of the seasonal mean Indian monsoon with a global atmospheric general circulation model. The seasonal mean precipitation is less than half that observed. This poor simulation in seasonal integrations is independent of the choice of initial conditions and global sea surface temperature data used. Experiments are performed to test the sensitivity of the Indian monsoon simulation to changes in orography, vegetation, soil, wetness, and cloudiness. The authors find that the deficiency of the model precipitation simulation may be attributed to the use of an enhanced orography in the integrations. Replacement of this orography with a mean orography results in a much more realistic simulation of Indian monsoon circulation and rainfall. Experiments with a linear primitive equation model on the sphere suggest that this striking improvement is due to modulations of the orographically forced waves in the lower troposphere. This improvement in the monsoon simulation is due to the kinematic and dynamical effects of changing the topography, rather than the thermal effects, which were minimal. The magnitude of the impact on the Indian monsoon of the other sensitivity experiments varied considerably, but was consistently less than the impact of using the mean orography. However, results from the soil moisture sensitivity experiments suggest a possibly important role for soil moisture in simulating tropical precipitation, including that associated with the Indian monsoon.

  10. Further study on highly sensitive AMS measurement of 53Mn

    NASA Astrophysics Data System (ADS)

    Kejun, Dong; Hao, Hu; Xianggao, Wang; Chaoli, Li; Ming, He; Zhenyu, Li; Shaoyong, Wu; Jiancheng, Liu; Guowen, Zheng; Heng, Li; Zhigang, Chen; Guangshan, Liu; Jian, Yuan; Shan, Jiang

    2012-08-01

    The AMS facility at China Institute of Atomic Energy has been equipped with a ΔE-Q3D detection system for the measurements of 53Mn. While the sample material of MnO2 and the extraction ions of MnO- were used previously in AMS measurement of 53Mn with fairly good results, a method has recently been developed with the extraction of MnF- from ion source using MnF2 and MnO2 + PbF2 as sample materials. As a result, a sensitivity of 10-14 (53Mn/Mn) has been achieved. Compared with the original MnO-/MnO2 approach, the method of MnF- extraction, combined with ΔE-Q3D detection technique, demonstrated an improved sensitivity for AMS measurement of 53Mn.

  11. Oxidation phenomena: MAAP4 sensitivity studies using CORA-13 experiment

    SciTech Connect

    Luche, J.; Jacqmin, L.G.

    1996-12-31

    In France, both Electricite de France and Framatome are using the modular accident analysis program (MAAP) version 4 code for severe accident scenario analyses. Commissariat a l`Energie Atomique, in collaboration with them, is investigating the code prediction capabilities on hydrogen production. The purpose of this work is to evaluate the fuel-clad oxidation model on the CORA-13 test results and to find the most sensitive parameters to this reaction, especially during reflooding.

  12. Gas Sensitivity Study of Polypyrrole Decorated Graphene Oxide Thick Film

    NASA Astrophysics Data System (ADS)

    Patil, Pritam; Gaikwad, Ganesh; Patil, Devidas Ramrao; Naik, Jitendra

    2016-04-01

    Polypyrrole (PPy) and graphene oxide (GO) nanocomposites were prepared by in situ polymerization method. The synthesized nanocomposites were characterized for current-voltage characteristic, Fourier transform infrared spectroscopy, X-ray diffraction and field emission scanning electron microscopy, which gave the evidence of the strong interaction between PPy nanofibers and GO nanosheets. The PPy/GO nanocomposites were used for the sensing of H2S, LPG, CO2 and NH3 gases respectively at room temperature. It was observed that PPy/GO nanocomposites with different GO weight ratios (5, 10 and 20 %) had better selectivity and sensitivity towards NH3 at room temperature.

  13. HCIT Contrast Performance Sensitivity Studies: Simulation Versus Experiment

    NASA Technical Reports Server (NTRS)

    Sidick, Erkin; Shaklan, Stuart; Krist, John; Cady, Eric J.; Kern, Brian; Balasubramanian, Kunjithapatham

    2013-01-01

    Using NASA's High Contrast Imaging Testbed (HCIT) at the Jet Propulsion Laboratory, we have experimentally investigated the sensitivity of dark hole contrast in a Lyot coronagraph for the following factors: 1) Lateral and longitudinal translation of an occulting mask; 2) An opaque spot on the occulting mask; 3) Sizes of the controlled dark hole area. Also, we compared the measured results with simulations obtained using both MACOS (Modeling and Analysis for Controlled Optical Systems) and PROPER optical analysis programs with full three-dimensional near-field diffraction analysis to model HCIT's optical train and coronagraph.

  14. Cascade sensitivity studies for KM3NeT

    NASA Astrophysics Data System (ADS)

    Fusco, Luigi Antonio

    2016-07-01

    KM3NeT is a future research infrastructure in the deep seas of the Mediterranean housing a large scale neutrino telescope. The first phase of construction of the telescope has started. Next step is an intermediate phase realising a detector volume of about one-third of the final detector volume. We report on calculations of the sensitivity of the KM3NeT detector to showering neutrino events, the strategy to optimise the detector to a cosmic neutrino flux analogous to the one reported by the IceCube Collaboration and the results of this strategy applied to the intermediate phase detector.

  15. An Initial Study of the Sensitivity of Aircraft Vortex Spacing System (AVOSS) Spacing Sensitivity to Weather and Configuration Input Parameters

    NASA Technical Reports Server (NTRS)

    Riddick, Stephen E.; Hinton, David A.

    2000-01-01

    A study has been performed on a computer code modeling an aircraft wake vortex spacing system during final approach. This code represents an initial engineering model of a system to calculate reduced approach separation criteria needed to increase airport productivity. This report evaluates model sensitivity toward various weather conditions (crosswind, crosswind variance, turbulent kinetic energy, and thermal gradient), code configurations (approach corridor option, and wake demise definition), and post-processing techniques (rounding of provided spacing values, and controller time variance).

  16. Sensitizing the sensitizer: the synthesis and photophysical study of bodipy-Pt(II)(diimine)(dithiolate) conjugates.

    PubMed

    Lazarides, Theodore; McCormick, Theresa M; Wilson, Kristina C; Lee, Soohyun; McCamant, David W; Eisenberg, Richard

    2011-01-19

    The dyads 3, 4, and 6, combining the Bodipy chromophore with a Pt(bpy)(bdt) (bpy = 2,2'-bipyridine, bdt = 1,2-benzenedithiolate, 3 and 6) or a Pt(bpy)(mnt) (mnt = maleonitriledithiolate, 4) moiety, have been synthesized and studied by UV-vis steady-state absorption, transient absorption, and emission spectroscopies and cyclic voltammetry. Comparison of the absorption spectra and cyclic voltammograms of dyads 3, 4, and 6 and those of their model compounds 1a, 2, 5, and 7 shows that the spectroscopic and electrochemical properties of the dyads are essentially the sum of their constituent chromophores, indicating negligible interaction of the constituent chromophores in the ground state. However, emission studies on 3 and 6 show a complete absence of both Bodipy-based fluorescence and the characteristic luminescence of the Pt(bpy)(bdt) unit. Dyad 4 shows a weak Pt(mnt)-based emission. Transient absorption studies show that excitation of the dyads into the Bodipy-based (1)ππ* excited state is followed by singlet energy transfer (SEnT) to the Pt(dithiolate)-based (1)MMLL'CT (mixed metal-ligand to ligand charge transfer) excited state (τ(SEnT)(3) = 0.6 ps, τ(SEnT)(4) = 0.5 ps, and τ(SEnT)(6) = 1.6 ps), which undergoes rapid intersystem crossing to the (3)MMLL'CT state due to the heavy Pt(II) ion. The (3)MMLL'CT state is then depopulated by triplet energy transfer (TEnT) to the low-lying Bodipy-based (3)ππ* excited state (τ(SEnT)(3) = 8.2 ps, τ(SEnT)(4) = 5 ps, and τ(SEnT)(6) = 160 ps). The transition assignments are supported by TD-DFT calculations. Both energy-transfer processes are shown to proceed via a Dexter electron exchange mechanism. The much longer time constants for dyad 6 relative to 3 are attributed to the significantly poorer coupling and resonance of charge-separated species that are intermediates in the electron exchange process. PMID:21175161

  17. The highly sensitive brain: an fMRI study of sensory processing sensitivity and response to others' emotions

    PubMed Central

    Acevedo, Bianca P; Aron, Elaine N; Aron, Arthur; Sangster, Matthew-Donald; Collins, Nancy; Brown, Lucy L

    2014-01-01

    Background Theory and research suggest that sensory processing sensitivity (SPS), found in roughly 20% of humans and over 100 other species, is a trait associated with greater sensitivity and responsiveness to the environment and to social stimuli. Self-report studies have shown that high-SPS individuals are strongly affected by others' moods, but no previous study has examined neural systems engaged in response to others' emotions. Methods This study examined the neural correlates of SPS (measured by the standard short-form Highly Sensitive Person [HSP] scale) among 18 participants (10 females) while viewing photos of their romantic partners and of strangers displaying positive, negative, or neutral facial expressions. One year apart, 13 of the 18 participants were scanned twice. Results Across all conditions, HSP scores were associated with increased brain activation of regions involved in attention and action planning (in the cingulate and premotor area [PMA]). For happy and sad photo conditions, SPS was associated with activation of brain regions involved in awareness, integration of sensory information, empathy, and action planning (e.g., cingulate, insula, inferior frontal gyrus [IFG], middle temporal gyrus [MTG], and PMA). Conclusions As predicted, for partner images and for happy facial photos, HSP scores were associated with stronger activation of brain regions involved in awareness, empathy, and self-other processing. These results provide evidence that awareness and responsiveness are fundamental features of SPS, and show how the brain may mediate these traits. PMID:25161824

  18. Sensitivity Studies of Air Ingress Acidents in Modular HTGRs

    SciTech Connect

    Ball, Sydney J; Richards, Matt; Shepelev, Sergey

    2008-01-01

    Postulated air ingress accidents, while of very low probability in a modular high-temperature gas-cooled reactor (HTGR), are of considerable interest to the plant designer, operator, and regulator because of the possibility that the core could sustain significant damage under some circumstances. Sensitivity analyses are described that cover a wide spectrum of conditions affecting outcomes of the postulated accident sequences, for both prismatic and pebble-bed core designs. The major factors affecting potential core damage are the size and location of primary system leaks, flow path resistances, the core temperature distribution, and the long-term availability of oxygen in the incoming gas from a confinement building. Typically, all the incoming oxygen entering the core area is consumed within the reactor vessel, so it is more a matter of where, not whether, oxidation occurs. An air ingress model with example scenarios and means for mitigating damage are described. Representative designs of modular HTGRs included here are a 400-MW(th) pebble-bed reactor (PBR), and a 600-MW(th) prismatic-core modular reactor (PMR) design such as the gas-turbine modular helium reactor (GT-MHR).

  19. Design tradeoff studies and sensitivity analysis, appendix B

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Further work was performed on the Near Term Hybrid Passenger Vehicle Development Program. Fuel economy on the order of 2 to 3 times that of a conventional vehicle, with a comparable life cycle cost, is possible. The two most significant factors in keeping the life cycle cost down are the retail price increment and the ratio of battery replacement cost to battery life. Both factors can be reduced by reducing the power rating of the electric drive portion of the system relative to the system power requirements. The type of battery most suitable for the hybrid, from the point of view of minimizing life cycle cost, is nickel-iron. The hybrid is much less sensitive than a conventional vehicle is, in terms of the reduction in total fuel consumption and resultant decreases in operating expense, to reductions in vehicle weight, tire rolling resistance, etc., and to propulsion system and drivetrain improvements designed to improve the brake specific fuel consumption of the engine under low road load conditions. It is concluded that modifications to package the propulsion system and battery pack can be easily accommodated within the confines of a modified carryover body such as the Ford Ltd.

  20. Does a Culturally Sensitive Smoking Prevention Program Reduce Smoking Intentions among Aboriginal Children? A Pilot Study

    ERIC Educational Resources Information Center

    McKennitt, Daniel W.; Currie, Cheryl L.

    2012-01-01

    The aim of the study was to determine if a culturally sensitive smoking prevention program would have short-term impacts on smoking intentions among Aboriginal children. Two schools with high Aboriginal enrollment were selected for the study. A grade 4 classroom in one school was randomly assigned to receive the culturally sensitive smoking…

  1. A Study of Young Children's Aesthetic Sensitivity to Drawing and Painting.

    ERIC Educational Resources Information Center

    Golomb, Claire; Helmund, Judith

    This study examines the emergence of aesthetic sensitivity in the young child as a maker of art and as a critic of the work of peers. Two studies were designed to explore the child's own, mostly implicit, assumptions about child art, sensitivity to stylistic and drawing system differences, and to compositional patterns that characterize the work…

  2. Assisted Sonication vs Conventional Transesterification Numerical Simulation and Sensitivity Study

    NASA Astrophysics Data System (ADS)

    Janajreh, Isam; Noorul Hussain, Mohammed; El Samad, Tala

    2015-10-01

    Transeterification is known as slow reaction that can take over several hours to complete as the two immiscible liquid reactants combine to form biodiesel and the less favorable glycerol. The quest of finding the perfect catalyst, optimal operational conditions, and reactor configuration to accelerate the reaction in mere few minutes that ensures high quality biodiesel, in economically viable way is coming along with sonication. This drastic reduction is a key enabler for the development of a continuous processing that otherwise is fairly costly and low throughput using conventional method. The reaction kinetics of sonication assisted as inferred by several authors is several time faster and this work implements these rates in a high fidelity numerical simulation model. This flow model is based on Navier-Stokes equations coupled with energy equation for non-isothermal flow and the transport equations of the multiple reactive species. The model is initially validated against experimental data from previous work of the authors using an annular reactor configuration. Following the validation, comparison of the reaction rate is shown to gain more insight to the distribution of the reaction and its attained rates. The two models (conventional and sonication) then compared on the basis of their sensitivity to the methane to oil molar ratio as the most pronounced process parameter. Both the exit reactor yield and the distribution of the species are evaluated with favorable yield under sonication process. These results pave the way to build a more robust process intensified reactor having an integrated selective heterogeneous catalyst to steer the reaction. This can avoid the downstream cleaning processes, cutting reaction time, and render economic benefit to the process.

  3. Regional Sensitivity to Neuroinflammation: In Vivo and In Vitro Studies

    SciTech Connect

    Liraz-Zaltsman, S.; Biegon, A.; Liraz-Zaltsman, S.; Alexandrovich, A.G.; Trembovler, V.; Fishbein, I.; Yaka, R.; Shohami, E.; Biegon, A.

    2010-11-23

    Neuroinflammation is involved in several acute-onset neuropathologies such as meningitis, encephalitis, stroke, and traumatic brain injury as well as in neurodegenerative diseases. All of these patholologies are associated with cognitive deficits. Using a model of pure neuroinflammation (intracisternal injection of endotoxin in mice), we tested the hypothesis that brain regions involved in cognition are the most vulnerable to inflammatory insults, and this vulnerability is an inherent property of neocortical neurons. Mice (n = 10/group) injected with endotoxin (LPS) or saline in the cisterna magna underwent neurobehavioral and cognitive testing followed by quantitative autoradiographic assessment of regional neuroinflammation with [3H]PK11195, an established marker of microgliosis. In parallel, cocultures of cortical and striatal neurons taken from embryonic day 19 rat embryos or postnatal day 1 mice expressing green fluorescent protein were exposed for 24 h to the proinflammatory cytokine TNFalpha, glutamate, or a combination of the two agents. LPS-treated mice exhibited significant deficits in memory and significant increases in specific PK11195 binding in cortical and hippocampal regions, but not in striatum. Cultured neurons of cortical origin showed significantly lower survival rate relative to striatal neurons in response to TNFalpha, glutamate, or a combination of the two agents. Furthermore, TNFalpha exerted neuroprotective rather than neurotoxic effects in the striatal but not in the cortical neurons. These results suggest that the cortex is inherently more sensitive than the striatum to the deleterious effects of neuroinflammation, and may offer an explanation for the preponderance of cognitive deficits in neuropathologies with a neuroinflammatory component.

  4. The sensitivity of the KeratinoSens™ assay to evaluate plant extracts: a pilot study.

    PubMed

    Andres, Eric; Sá-Rocha, Vanessa M; Barrichello, Carla; Haupt, Tina; Ellis, Graham; Natsch, Andreas

    2013-06-01

    Several tests to assess skin sensitization hazard are in peer-review for pre-validation. These tests, as well as the animal tests they aim to replace, were developed (and validated) for the testing of pure substances. However, in the cosmetic field, active ingredients are often mixtures from natural sources. It is therefore important to understand which tests could be used to evaluate their safety. Here we describe a proof-of-concept study to test whether the KeratinoSens(™) assay is able to detect sensitizing constituents within botanical mixtures. Four extracts were spiked with different doses of the sensitizers citral, cinnamic aldehyde and isoeugenol. The tested extracts were negative in the test whereas they became positive in most cases when spiked with the sensitizers. Analysis of the results from the samples spiked with different doses allowed the determination of the minimal level of sensitizers being detectable. The contribution to sensitization potential of doses of 2% and above of the spiked sensitizers were reliably detected. There were limitations for an extract with high cytotoxicity, in which case detection of the artificially spiked sensitizers proved difficult. This study gives a proof of principle for testing of mixtures in the KeratinoSens(™) assay and indicates how sensitive the assay is to detect minor components with sensitizing potential. PMID:23428960

  5. SENSITIVITY ANALYSIS AND THE DESIGN OF GAS UPTAKE INHALATION STUDIES

    EPA Science Inventory

    Gas uptake studies analyzed by physiologically based pharmacokinetic (PBPK) models have been used to estimate metabolic parameters for many volatiles. he metabolic constants Vmax, Km, and Kf are typically inferred from the decline in chemical concentration observed in closed cham...

  6. Preliminary studies of combustor sensitivity to alternative fuels

    NASA Technical Reports Server (NTRS)

    Humenik, F. M.

    1980-01-01

    Combustion problems associated with using alternative fuels ground power and aeropropulsion applications were studied. Rectangular sections designed to simulate large annular combustor test conditions were examined. The effects of using alternative fuels with reduced hydrogen content, increased aromatic content, and a broad variation in fuel property characteristics were also studied. Data of special interest were collected which include: flame radiation characteristics in the various combustor zones; the correponding increase in liner temperature from increased radiant heat flux; the effect of fuel bound nitrogen on oxides of nitrogen (NO sub x) emissions; and the overall total effect of fuel variations on exhaust emissions.

  7. Host Language Proficiency, Intercultural Sensitivity, and Study Abroad

    ERIC Educational Resources Information Center

    Jackson, Jane

    2011-01-01

    The number of foreign language students who join study abroad programs continues to increase annually, especially those who take part in short-term sojourns lasting eight weeks or less. What can be accomplished in such a short stay in the host culture? Is it possible for sojourners to enhance their proficiency in the host language and…

  8. Evaluation of the Use of Team Teaching for Delivering Sensitive Content: A Pilot Study

    ERIC Educational Resources Information Center

    Kerridge, Joanna; Kyle, Gaye; Marks-Maran, Diane

    2009-01-01

    Many programmes in further and higher education contain sensitive areas of content, such as diversity, racism, power and privilege, breaking bad news, counselling, sex education and ethical decision making. Team teaching may be a useful method for delivering sensitive areas of course content. This article presents a pilot study that was undertaken…

  9. Teaching Strategies and Practices that Promote a Culturally Sensitive Nursing Education: A Delphi Study

    ERIC Educational Resources Information Center

    Dewald, Robin J.

    2010-01-01

    The purpose of this study was to explore teaching strategies that promote a culturally sensitive nursing education and culturally sensitive nursing. The diversity of Americans has increased. Thus, the nursing student population and patient population have both become more diverse. Nursing education programs, therefore, need to know the best…

  10. Observed Sensitivity during Family Interactions and Cumulative Risk: A Study of Multiple Dyads per Family

    ERIC Educational Resources Information Center

    Browne, Dillon T.; Leckie, George; Prime, Heather; Perlman, Michal; Jenkins, Jennifer M.

    2016-01-01

    The present study sought to investigate the family, individual, and dyad-specific contributions to observed cognitive sensitivity during family interactions. Moreover, the influence of cumulative risk on sensitivity at the aforementioned levels of the family was examined. Mothers and 2 children per family were observed interacting in a round robin…

  11. A Taxometric Study of the Latent Structure of Disgust Sensitivity: Converging Evidence for Dimensionality

    ERIC Educational Resources Information Center

    Olatunji, Bunmi O.; Broman-Fulks, Joshua J.

    2007-01-01

    Disgust sensitivity has recently been implicated as a specific vulnerability factor for several anxiety-related disorders. However, it is not clear whether disgust sensitivity is a dimensional or categorical phenomenon. The present study examined the latent structure of disgust by applying three taxometric procedures (maximum eigenvalue, mean…

  12. An avionics sensitivity study. Volume 1: Operational considerations

    NASA Technical Reports Server (NTRS)

    Scott, R. W.; Mcconkey, E. D.

    1976-01-01

    Equipment and operational concepts affecting aircraft in the terminal area are reported. Curved approach applications and modified climb and descent procedures for minimum fuel consumption are considered. The curved approach study involves the application of MLS guidance to enable execution of the current visual approach to Washington National Airport under instrument flight conditions. The operational significance and the flight path control requirements involved in the application of curved approach paths to this situation are considered. Alternative flight path control regimes are considered to achieve minimum fuel consumption subject to constraints related to air traffic control requirements, flight crew and passenger reactions, and airframe and powerplant limitations.

  13. A pseudo-state sensitivity study on hydrogenic ions

    NASA Astrophysics Data System (ADS)

    Ballance, C. P.; Badnell, N. R.; Smyth, E. S.

    2003-09-01

    An electron-impact excitation study of light hydrogenic ions has been carried out to quantify the effects of coupling to high bound/continuum states utilizing the R-matrix with pseudo-states method. As the ionization stage increases, the neglect of loss of flux into high-lying excitation/ionization channels impacts less upon excitation between the bound terms explicitly included within our close coupling expansion. C5+ is used as our benchmark study. The differences in Maxwell averaged collision strengths between a standard R-matrix calculation and those of a similar pseudo-state model across a range of temperatures shall be our criteria for judging differences. We carried out calculations for He+, Li2+, Be3+, B4+, C5+, O7+ and Ne9+ so as to provide excitation data amongst terms up to n = 5. Pseudo-state calculations were carried out for the first five ions, following a similar model to earlier neutral hydrogen work, whilst non-pseudo-state calculations sufficed for the remaining two ions. The results of these seven calculations will enhance existing excitation data sets for use in the modelling of controlled nuclear fusion plasma experiments.

  14. Requirement sensitivity studies for a future Landsat sensor

    NASA Astrophysics Data System (ADS)

    Cui, Zhaoyu; Montanaro, Matthew; Gerace, Aaron; Schott, John R.; Markham, Brian

    2015-09-01

    The Landsat program has collected imagery of the Earth for the past 40 years. Although both Landsat 7 and 8 are currently operating on-orbit, the next generation Landsat mission is already being planned. Concept studies for this mission include reproducing the Landsat 8 design (mainly push-broom imaging architecture). The definition of science requirements is an important step towards the development of instrument specifications. At this early stage, a re-evaluation of the Landsat requirements is beneficial since they might be flexible enough to relax in some areas to possibly save on manufacturing costs or may need to be tightened in other areas to produce better science products. The investigations presented here focused on spatial aliasing and spectral banding effects. The specifications of these two key performance requirements were taken from the Landsat 8 Operational Land Imager (OLI) sensor as a starting point for the analyses. They were then adjusted to determine their effects on the final image products through the use of standard radiometry equations and synthetic Earth scene data. The results of the modeling efforts for these two requirements concepts are presented here and could be used as a template for future instrument studies.

  15. Water isotopes and the Eocene. A tectonic sensitivity study

    NASA Astrophysics Data System (ADS)

    Legrande, A. N.; Roberts, C. D.; Tripati, A.; Schmidt, G. A.

    2009-04-01

    The early Eocene (54 Million years ago) is one of the warmest periods in the last 65 Million years. Its climate is postulated to have been the result of enhanced greenhouse gas concentration, with CO2 roughly 4 times pre-industrial and methane 7 times pre-industrial concentrations. One interesting feature of this period to emerge recently is the intermittent presence of fossilized Azolla, a type of freshwater fern, in the Arctic Ocean. Synchronous (within dating error) with this appearance were major changes in the restriction of the Arctic Ocean and the other global oceans. We investigate this time period using the Goddard Institute for Space Studies ModelE-R, a fully coupled atmosphere-ocean general circulation model that incorporates water isotopes throughout the hydrologic cycle, making it an ideal model to test hypotheses of past climate change and to compare to paleoclimate proxy data. We assess the impact of tectonic variability by using minimal and maximal levels of restriction for the Arctic Ocean seaways. We find that the modulation of connectivity of these basins dramatically alters global salinity distribution, leading to large changes in ocean circulation. Greater restriction of the Arctic Basin is associated with fresh and relatively warmer conditions. The same mechanisms responsible for this redistribution of salt also change the global distribution of water isotopes, and can alias (water isotope) proxy climate signals of warmth.

  16. Sensitivity Studies of the Radar-Rainfall Error Models

    NASA Astrophysics Data System (ADS)

    Villarini, G.; Krajewski, W. F.; Ciach, G. J.

    2007-12-01

    It is well acknowledged that there are large uncertainties associated with the operational quantitative precipitation estimates produced by the U.S. national network of WSR-88D radars. These errors are due to the measurement principles, parameter estimation, and not fully understood physical processes. Comprehensive quantitative evaluation of these uncertainties is still at an early stage. The authors proposed an empirically-based model in which the relation between true rainfall (RA) and radar-rainfall (RR) could be described as the product of a deterministic distortion function and a random component. However, how different values of the parameters in the radar-rainfall algorithms used to create these products impact the model results still remains an open question. In this study, the authors investigate the effects of different exponents in the Z-R relation (Marshall- Palmer, NEXRAD, and tropical) and of an anomalous propagation (AP) removal algorithm. Additionally, they generalize the model to describe the radar-rainfall uncertainties in the additive form. This approach is fully empirically based and rain gauge estimates are considered as an approximation of the true rainfall. The proposed results are based on a large sample (six years) of data from the Oklahoma City radar (KTLX) and processed through the Hydro-NEXRAD software system. The radar data are complemented with the corresponding rain gauge observations from the Oklahoma Mesonet, and the Agricultural Research Service Micronet.

  17. A sensitivity study of storm cyclones with a mesoscale model

    NASA Astrophysics Data System (ADS)

    Radtke, K. S.; Tetzlaff, G.

    2003-04-01

    Extra tropical storms caused noticeable damages in the last decades. The evolution of strong cyclones is investigated by simulations with the nonhydrostatic limited area model 'Lokal Modell' (LM) of the German Weather Service (DWD). Which Conditions become important to distinguish an common cyclone from an storm-cyclone? Intense cyclones are mostly characterised by two typical large-scale features: high baroclinicity along the track of the low pressure system and a region of high equivalent potential temperature. For this purpose the observed values of the horizontal temperature gradient and the distribution of air moisture are varied and were used as forcing data, in such a way the development of storms was modified. The forcing data for the LM were generated by the global model of the DWD. Therefore data of real cyclones, such as the low Ginger, which occurred in 2000, were used. As the LM simulates only a limited area, the lateral bounds become problematic because of the manipulated forcing data. A procedure is tested, in order to prevent these problems. In this manner ensembles of storm scenarios were produced. The effects of various conditions were studied. Here in particular the changes in the surface velocity field were of interest. In the case of Ginger, an increase of the temperature gradient about 10 K causes an increasing of the maximum velocity about 3 m/s.

  18. Microbeam studies of the sensitivity of structures within living cells

    NASA Technical Reports Server (NTRS)

    Braby, L. A.

    1992-01-01

    Determining the biological effects of low doses of radiation with high linear energy transfer (LET) is complicated by the stochastic nature of charged-particle interactions. Populations of cells exposed to very low radiation doses contain a few cells which have been hit by a charged particle, while the majority of the cells receive no radiation damage. At somewhat higher doses, a few cells receive two or more events. Because the effects of damage produced by separate events can interact in the cell, we have had to make assumptions about the nature of these interactions in order to interpret the results of the experiments. Many of those assumptions can be tested if we can be sure of the number of charged-particle events which occur in individual cells, and correlate this number with the biological effect. We have developed a special irradiation facility at Pacific Northwest Laboratory (PNL) to control the actual number of charged particle tracks that pass through cell nuclei. The beam from a 2 MeV tandem accelerator is collimated to approximately 5 microns. Cells, grown in special dishes with 1.5 microns thick plastic bottoms, are positioned so that the desired portion of the cell aligns with the collimator. A shutter in the beam line is opened and closed after the desired number of particle tracks has been counted. This approach can be used to investigate the effects of the interaction between irradiated and unirradiated cells in an organized system, as well as to study the effects of spatial and temporal distribution of radiation damage within single cells.(ABSTRACT TRUNCATED AT 250 WORDS).

  19. Lidar studies on climate sensitivity characteristics of tropical cirrus clouds

    NASA Astrophysics Data System (ADS)

    Motty, G. S.; Jayeshlal, G. S.; Satyanarayana, Malladi; Mahadevan Pillai, V. P.

    2016-05-01

    The cirrus clouds play an important role in the Earth's radiation budget due to their high frequency of occurrence, non-spherical ice crystal formations, and variability in the scattering/absorption characteristics. Mostly, the tropical cirrus clouds are considered as greenhouse modulators. Thus the parameterization of tropical cirrus clouds in terms of the micro- physical properties and the corresponding radiative effects are highly important for the climate studies. For characterizing the radiative properties of cirrus clouds, which depend on the size, shape and number of the ice crystals, the knowledge of extinction coefficient (σ) and optical depth (τ) are necessary. The σ provides information needed for understanding the influence of the scatterers on the radiative budget whereas the τ gives an indication on the composition and thickness of the cloud. Extensive research on the tropical cirrus clouds has been carried out by using a ground based and satellite based lidar systems. In this work, the characteristics of tropical cirrus cloud derived by using the data from the ground based lidar system over the tropical site Gadanki [13.5°N, 79.2°E], India during 2010 are presented. Some of the results are compared with those obtained by us from satellite based CALIOP lidar observations of the CALIPSO mission. It is observed that there is a strong dependence of the some of the physical properties such as occurrence height, cloud temperature and the geometrical thickness on the microphysical parameters in terms of extinction coefficient and optical depth. The correlation of both the σ and τ with temperature is also observed.

  20. A taxometric study of the latent structure of disgust sensitivity: converging evidence for dimensionality.

    PubMed

    Olatunji, Bunmi O; Broman-Fulks, Joshua J

    2007-12-01

    Disgust sensitivity has recently been implicated as a specific vulnerability factor for several anxiety-related disorders. However, it is not clear whether disgust sensitivity is a dimensional or categorical phenomenon. The present study examined the latent structure of disgust by applying three taxometric procedures (maximum eigenvalue, mean above minus below a cut, and latent-mode factor analysis) to data collected from 2 large nonclinical samples on 2 different measures of disgust sensitivity. Disgust sensitivity in the first sample (n=1,153) was operationalized by disgust reactions to food, animals, body products, sex, body envelope violations, death, hygiene, and sympathetic magic, as assessed by the Disgust Sensitivity Scale (J. Haidt, C. McCauley, & P. Rozin, 1994). Disgust Sensitivity Scale indicators of core, animal reminder, and contamination disgust were also examined in the 1st sample. Disgust sensitivity in the 2nd independent sample (n=1,318) was operationalized by disgust reactions to animals, injections and blood draws, mutilation and death, rotting foods, and odors, as assessed by the Disgust Emotion Scale (R. A. Kleinknecht, E. E. Kleinknecht, & R. M. Thorndike, 1997). Results across both samples provide converging evidence that disgust sensitivity is best conceptualized as a dimensional construct, present to a greater or lesser extent in all individuals. These findings are discussed in relation to the conceptualization and assessment of disgust sensitivity as a specific dimensional vulnerability for certain anxiety and related disorders. PMID:18085936

  1. Spectral sensitivity studies on the visual system of the praying mantis, Tenodera sinensis.

    PubMed

    Sontag, C

    1971-01-01

    In these studies a constant ERG response was used as a measure of visual sensitivity to different wavelengths of light. The dark-adapted compound eye of Tenodera sinensis is dominated by a single class of photoreceptors. with a major peak of sensitivity at about 510-520 nm, and with a minor peak of sensitivity in the near-ultraviolet region at about 370 nm. The dark-adapted dorsal ocellus does not contain a homogeneous population of sensory receptors. The sensitivity function of the dark-adapted ocellus to longer wavelength light (yellow and red) is determined by a single receptor with a major peak of sensitivity in the green at 510-520 nm with some sensitivity in the near-ultraviolet. Sensitivity at shorter wavelengths (near-ultraviolet and blue), however, involves the stimulation of both this and a near-ultraviolet-sensitive receptor with a maximum sensitivity at about 370 nm. Anatomically, the sensory cells of the dorsal ocellus of Tenodera were determined histologically to be grouped into two distinct regions, each group making its own separate contribution to the ocellar nerve. This may represent the separation of two different photoreceptor types in the ocellus of the mantis. PMID:5539340

  2. CRETACEOUS CLIMATE SENSITIVITY STUDY USING DINOSAUR & PLANT PALEOBIOGEOGRAPHY

    NASA Astrophysics Data System (ADS)

    Goswami, A.; Main, D. J.; Noto, C. R.; Moore, T. L.; Scotese, C.

    2009-12-01

    differed markedly from the present. Studies of past biotas and their changes may elucidate the role of climatic and geographic factors in driving changes in species distributions, ecosystem organization, and evolutionary dynamics over time.

  3. Dentine sensitivity risk factors: A case–control study

    PubMed Central

    Mafla, Ana Cristina; Lopez-Moncayo, Luis Fernando

    2016-01-01

    Objective: To identify the clinical and psychological risk factors associated with dentine hypersensitivity (DH) in order to provide an early diagnosis and preventive therapy. Materials and Methods: A nested case–control study was design between 2011 and 2012. A total of 61 DH cases and 122 controls participated in this investigation. Cases and controls were matched for sex, group of age and socioeconomic status in a ratio of 1:2. DH to different stimuli such as cold, heat, acid, and sweet was asked in patient interviews, and dental examinations were used to detect DH. Clinical and psychological risk factors such as dental hygiene, periodontal disease, acid diet, alcohol consumption, psychological stress, and psychopathological symptoms were inquired. Psychological stress was measured through the PSS-10 and psychopathological symptoms were evaluated by SCL-90-R in Spanish. Descriptive and univariate binary logistic regression analysis were performed to estimate the association between clinical and psychological risk factors and the presence of DH. Results: Toothpaste abrasivity (odds ratio [OR] 1.881, 95% confidence interval [CI] 1.010–3.502, P = 0.045), gingival recession (OR 2.196, 95% CI 1.020–4.728, P = 0.041), and periodontal therapy (OR 5.357, 95% CI 2.051–13.993, P < 0.001) were associated with DH. Subjects with perceived stress (OR 1.211, 95%, CI 0.518–2.833, P = 0.658), obsessive-compulsive (OR 1.266, 95%, CI 0.494–3.240, P = 0.623) and hostility (OR 1.235, 95%, CI 0.507–3.007, P = 0.642) symptoms had a clinical greater odd of DH. Conclusion: Oral hygiene products and periodontal conditions are important risk factors for DH. Individuals with perceived stress, obsessive-compulsive, and hostility symptoms may increase a clinical risk for this entity. Targeting to dental counseling focused on oral hygiene products, periodontal therapy and a psychological evaluation may be promising in DH prevention. PMID:27011732

  4. Concept Study: Exploration and Production in Environmentally Sensitive Arctic Areas

    SciTech Connect

    Shirish Patil; Rich Haut; Tom Williams; Yuri Shur; Mikhail Kanevskiy; Cathy Hanks; Michael Lilly

    2008-12-31

    The Alaska North Slope offers one of the best prospects for increasing U.S. domestic oil and gas production. However, this region faces some of the greatest environmental and logistical challenges to oil and gas production in the world. A number of studies have shown that weather patterns in this region are warming, and the number of days the tundra surface is adequately frozen for tundra travel each year has declined. Operators are not allowed to explore in undeveloped areas until the tundra is sufficiently frozen and adequate snow cover is present. Spring breakup then forces rapid evacuation of the area prior to snowmelt. Using the best available methods, exploration in remote arctic areas can take up to three years to identify a commercial discovery, and then years to build the infrastructure to develop and produce. This makes new exploration costly. It also increases the costs of maintaining field infrastructure, pipeline inspections, and environmental restoration efforts. New technologies are needed, or oil and gas resources may never be developed outside limited exploration stepouts from existing infrastructure. Industry has identified certain low-impact technologies suitable for operations, and has made improvements to reduce the footprint and impact on the environment. Additional improvements are needed for exploration and economic field development and end-of-field restoration. One operator-Anadarko Petroleum Corporation-built a prototype platform for drilling wells in the Arctic that is elevated, modular, and mobile. The system was tested while drilling one of the first hydrate exploration wells in Alaska during 2003-2004. This technology was identified as a potentially enabling technology by the ongoing Joint Industry Program (JIP) Environmentally Friendly Drilling (EFD) program. The EFD is headed by Texas A&M University and the Houston Advanced Research Center (HARC), and is co-funded by the National Energy Technology Laboratory (NETL). The EFD

  5. Observed sensitivity during family interactions and cumulative risk: A study of multiple dyads per family.

    PubMed

    Browne, Dillon T; Leckie, George; Prime, Heather; Perlman, Michal; Jenkins, Jennifer M

    2016-07-01

    The present study sought to investigate the family, individual, and dyad-specific contributions to observed cognitive sensitivity during family interactions. Moreover, the influence of cumulative risk on sensitivity at the aforementioned levels of the family was examined. Mothers and 2 children per family were observed interacting in a round robin design (i.e., mother-older sibling, mother younger-sibling and sibling-dyad, N = 385 families). Data were dyadic, in that there were 2 directional scores per interaction, and were analyzed using a multilevel formulation of the Social Relations Model. Variance partitioning revealed that cognitive sensitivity is simultaneously a function of families, individuals and dyads, though the importance of these components varies across family roles. Cognitive sensitivity for mothers was primarily attributable to individual differences, whereas cognitive sensitivity for children was predominantly attributable to family and dyadic differences, especially for youngest children. Cumulative risk explained family and individual variance in cognitive sensitivity, particularly when actors were older or in a position of relative competence or authority (i.e., mother to children, older to younger siblings). Overall, this study demonstrates that cognitive sensitivity operates across levels of family organization, and is negatively impacted by psychosocial risk. (PsycINFO Database Record PMID:27337515

  6. Sensitivity study of ice crystal optical properties in the 874 GHz submillimeter band

    NASA Astrophysics Data System (ADS)

    Tang, Guanglin; Yang, Ping; Wu, Dong L.

    2016-07-01

    Testing of an 874 GHz submillimeter radiometer on meteorological satellites is being planned to improve ice water content retrievals. In this paper we study the optical properties of ice cloud particles in the 874 GHz band. The results show that the bulk scattering and absorption coefficients of an ensemble of ice cloud particles are sensitive to the particle shape and effective diameter, whereas the latter is also sensitive to temperature. The co-polar back scattering cross-section is not sensitive to particle shape, temperature, and the effective diameter in the range of 50-200 μm.

  7. Neural correlates of anxiety sensitivity in panic disorder: A functional magnetic resonance imaging study.

    PubMed

    Poletti, Sara; Radaelli, Daniele; Cucchi, Michele; Ricci, Liana; Vai, Benedetta; Smeraldi, Enrico; Benedetti, Francesco

    2015-08-30

    Panic disorder has been associated with dysfunctional neuropsychological dimensions, including anxiety sensitivity. Brain-imaging studies of the neural correlates of emotional processing have identified a network of structures that constitute the neural circuitry for emotions. The anterior cingulate cortex (ACC), medial prefrontal cortex (mPFC) and insula, which are part of this network, are also involved in the processing of threat-related stimuli. The aim of the study was to investigate if neural activity in response to emotional stimuli in the cortico-limbic network is associated to anxiety sensitivity in panic disorder. In a sample of 18 outpatients with panic disorder, we studied neural correlates of implicit emotional processing of facial affect expressions with a face-matching paradigm; correlational analyses were performed between brain activations and anxiety sensitivity. The correlational analyses performed showed a positive correlation between anxiety sensitivity and brain activity during emotional processing in regions encompassing the PFC, ACC and insula. Our data seem to confirm that anxiety sensitivity is an important component of panic disorder. Accordingly, the neural underpinnings of anxiety sensitivity could be an interesting focus for treatment and further research. PMID:26071623

  8. A retrospective study of peanut and tree nut allergy: Sensitization and correlations with clinical manifestations

    PubMed Central

    Yang, Lihua; Clements, Stacy

    2015-01-01

    Peanut (PN) and tree nut (TN) allergies are among the leading causes of fatal food-induced anaphylaxis and are increasing in prevalence, especially in children. Their cosensitization and concurrent clinical allergy have been understudied. This retrospective study investigated the correlation between PN and TN allergy, both in terms of in vitro sensitization (IVS) and clinical allergic manifestations. We conducted a retrospective medical record review at the Allergy Clinic at University Hospital of Brooklyn. Fourteen hundred six charts were reviewed, of which 76 (5.4%) had documented relevant clinical allergy: PN allergy but not TN allergy (n = 29) or TN allergy but not PN allergy (n = 11) or both (n = 30). Six patients with PN allergy but no TN exposure history were not included in the analysis. The majority of patients (67/76, 88.1%) had a concurrent history of asthma, rhinoconjunctivitis, or AD. Sensitivity of TN IVS predicting PN IVS was 38/39 (97%). Similarly, sensitivity of PN IVS predicting TN IVS was 38/42 (91%). Sensitivity of TN clinical allergy predicting PN allergy was 30/59 (51%). Sensitivity of PN clinical allergy predicting TN allergy was 30/41 (73%). The total number of organ systems involved in reported clinical reactions correlated with IVS to TN (p = 0.004) but not IVS to PN (p = 0.983). In summary, we found PN sensitization predicts TN sensitization in vitro, with lower predictability for clinical reactions. PMID:25860169

  9. Nursing students’ understanding of factors influencing ethical sensitivity: A qualitative study

    PubMed Central

    Borhani, Fariba; Abbaszadeh, Abbas; Mohsenpour, Mohaddeseh

    2013-01-01

    Background: Ethical sensitivity is considered as a component of professional competency of nurses. Its effects on improvement of nurses’ ethical performance and the therapeutic relationship between nurses and patients have been reported. However, very limited studies have evaluated ethical sensitivity. Since no previous Iranian research has been conducted in this regard, the present study aimed to review nursing students’ understanding of effective factors on ethical sensitivity. Materials and Methods: This qualitative study was performed in Kerman, Iran, during 2009. It used semi-structured individual interviews with eight MSc nursing students to assess their viewpoints. It also included two focus groups. Purposive sampling was continued until data saturation. Data were analyzed using manifest content analysis. Results: The students’ understanding of factors influencing ethical sensitivity were summarized in five main themes including individual and spiritual characteristics, education, mutual understanding, internal and external controls, and experience of an immoral act. Conclusions: The findings of this study create a unique framework for sensitization of nurses in professional performance. The application of these factors in human resource management is reinforcement of positive aspects and decrease in negative aspects, in education can use for educational objectives setting, and in research can designing studies based on this framework and making related tools. It is noteworthy that presented classification was influenced by students themselves and mentioned to a kind of learning activity by them. PMID:24403928

  10. Study of the Sensitization on the Grain Boundary in Austenitic Stainless Steel Aisi 316

    NASA Astrophysics Data System (ADS)

    Kocsisová, Edina; Dománková, Mária; Slatkovský, Ivan; Sahul, Martin

    2014-12-01

    Intergranular corrosion (IGC) is one of the major problems in austenitic stainless steels. This type of corrosion is caused by precipitation of secondary phases on grain boundaries (GB). Precipitation of the secondary phases can lead to formation of chromium depleted zones in the vicinity of grain boundaries. Mount of the sensitization of material is characterized by the degree of sensitization (DOS). Austenitic stainless steel AISI 316 as experimental material had been chosen. The samples for the study of sensitization were solution annealed on 1100 °C for 60 min followed by water quenching and then sensitization by isothermal annealing on 700 °C and 650 °C with holding time from 15 to 600 min. Transmission electron microscopy (TEM) was used for identification of secondary phases. Electron backscattered diffraction (EBSD) was applied for characterization of grain boundary structure as one of the factors which influences on DOS.

  11. Sensitivity and uncertainty in crop water footprint accounting: a case study for the Yellow River Basin

    NASA Astrophysics Data System (ADS)

    Zhuo, L.; Mekonnen, M. M.; Hoekstra, A. Y.

    2014-01-01

    Water Footprint Assessment is a quickly growing field of research, but as yet little attention has been paid to the uncertainties involved. This study investigates the sensitivity of water footprint estimates to changes in important input variables and quantifies the size of uncertainty in water footprint estimates. The study focuses on the green (from rainfall) and blue (from irrigation) water footprint of producing maize, soybean, rice, and wheat in the Yellow River Basin in the period 1996-2005. A grid-based daily water balance model at a 5 by 5 arcmin resolution was applied to compute green and blue water footprints of the four crops in the Yellow River Basin in the period considered. The sensitivity and uncertainty analysis focused on the effects on water footprint estimates at basin level (in m3 t-1) of four key input variables: precipitation (PR), reference evapotranspiration (ET0), crop coefficient (Kc), and crop calendar. The one-at-a-time method was carried out to analyse the sensitivity of the water footprint of crops to fractional changes of individual input variables. Uncertainties in crop water footprint estimates were quantified through Monte Carlo simulations. The results show that the water footprint of crops is most sensitive to ET0 and Kc, followed by crop calendar and PR. Blue water footprints were more sensitive to input variability than green water footprints. The smaller the annual blue water footprint, the higher its sensitivity to changes in PR, ET0, and Kc. The uncertainties in the total water footprint of a crop due to combined uncertainties in climatic inputs (PR and ET0) were about ±20% (at 95% confidence interval). The effect of uncertainties in ET0 was dominant compared to that of precipitation. The uncertainties in the total water footprint of a crop as a result of combined key input uncertainties were on average ±26% (at 95% confidence level). The sensitivities and uncertainties differ across crop types, with highest sensitivities

  12. Image quality and dose efficiency of high energy phase sensitive x-ray imaging: Phantom studies

    PubMed Central

    Wong, Molly Donovan; Wu, Xizeng; Liu, Hong

    2014-01-01

    The goal of this preliminary study was to perform an image quality comparison of high energy phase sensitive imaging with low energy conventional imaging at similar radiation doses. The comparison was performed with the following phantoms: American College of Radiology (ACR), contrast-detail (CD), acrylic edge and tissue-equivalent. Visual comparison of the phantom images indicated comparable or improved image quality for all phantoms. Quantitative comparisons were performed through ACR and CD observer studies, both of which indicated higher image quality in the high energy phase sensitive images. The results of this study demonstrate the ability of high energy phase sensitive imaging to overcome existing challenges with the clinical implementation of phase contrast imaging and improve the image quality for a similar radiation dose as compared to conventional imaging near typical mammography energies. In addition, the results illustrate the capability of phase sensitive imaging to sustain the image quality improvement at high x-ray energies and for – breast – simulating phantoms, both of which indicate the potential to benefit fields such as mammography. Future studies will continue to investigate the potential for dose reduction and image quality improvement provided by high energy phase sensitive contrast imaging. PMID:24865208

  13. Does Sensitivity to Orthographic Regularities Influence Reading and Spelling Acquisition? A 1-Year Prospective Study

    ERIC Educational Resources Information Center

    Rothe, Josefine; Schulte-Körne, Gerd; Ise, Elena

    2014-01-01

    Recent studies focused on the influence of orthographic processing on reading and spelling performance. It was found that orthographic processing is an independent predictor of reading and spelling performance in different languages and children of different ages. This study investigated sensitivity to orthographic regularities in German-speaking…

  14. Perinatal undernutrition facilitates morphine sensitization and cross-sensitization to cocaine in adult rats: a behavioral and neurochemical study.

    PubMed

    Velazquez, E E; Valdomero, A; Orsingher, O A; Cuadra, G R

    2010-01-20

    The development of sensitization to the locomotor effects of morphine and cross-sensitization between morphine and cocaine were evaluated in adult rats submitted to a protein malnutrition schedule from the 14th day of gestation up to 30 days of age (D-rats), and compared with well-nourished animals (C-rats). Dose-response curves to morphine-induced locomotor activity (5, 7.5, 10 or 15 mg/kg, i.p., every other day for 5 days) revealed a shift to the left in D-rats compared to C-rats. This implies that D-rats showed behavioral sensitization to the lower dose of morphine used (5 mg/kg), which was ineffective in C-rats. Furthermore, when a cocaine challenge (10 mg/kg, i.p) was given 48 h after the last morphine administration, only D-rats exhibited cross-sensitization in morphine-pretreated animals (7.5 and 10 mg/kg). In order to correlate the differential response observed with the functioning of the mesocorticolimbic dopaminergic system, extracellular dopamine (DA) levels were measured in the nucleus accumbens (core and shell) and the dorsal caudate-putamen. A challenge with cocaine in morphine pre-exposed animals produced an increase in DA release, but only in the nucleus accumbens "core" of D-rats. Similar DA levels were found in the nucleus accumbens "shell" and in the dorsal caudate-putamen of both groups. Finally, these results demonstrate that D-rats had a lower threshold for developing both a progressive behavioral sensitization to morphine and a cross-sensitization to cocaine. In accordance with these behavioral findings, a higher responsiveness of the nucleus accumbens core, expressed by increased DA levels, both basal and after cocaine challenge, was observed in D-rats. PMID:19892003

  15. An internet-based study on the relation between disgust sensitivity and emetophobia.

    PubMed

    van Overveld, Mark; de Jong, Peter J; Peters, Madelon L; van Hout, Wiljo J P J; Bouman, Theo K

    2008-01-01

    In the etiology of disgust-relevant psychopathology, such as emetophobia (fear of vomiting), two factors may be important: disgust propensity, i.e., how quickly the individual experiences disgust, and disgust sensitivity, i.e., how negatively does the individual evaluate this disgust experience [van Overveld, W. J. M., de Jong, P. J., Peters, M. L., Cavanagh, K., & Davey, G. C. L. (2006). Disgust propensity and disgust sensitivity: separate constructs that are differentially related to specific fears. Personality and Individual Differences, 41, 1241-1252]. Hence, the current study examines whether emetophobic participants display elevated levels of disgust propensity and sensitivity, and whether these factors are differentially related to emetophobia. A group of emetophobic members of a Dutch website on emetophobia (n=172), and a control group (n=39) completed an internet survey containing the Emetophobia Questionnaire, Disgust Propensity and Sensitivity Scale-Revised, Disgust Scale, and Disgust Questionnaire. Results showed that the emetophobic group displayed significantly elevated levels of both disgust propensity and disgust sensitivity compared to the control group. Most importantly, disgust sensitivity consistently was the best predictor of emetophobic complaints. PMID:17517487

  16. Study sensitivity: Evaluating the ability to detect effects in systematic reviews of chemical exposures.

    PubMed

    Cooper, Glinda S; Lunn, Ruth M; Ågerstrand, Marlene; Glenn, Barbara S; Kraft, Andrew D; Luke, April M; Ratcliffe, Jennifer M

    2016-01-01

    A critical step in systematic reviews of potential health hazards is the structured evaluation of the strengths and weaknesses of the included studies; risk of bias is a term often used to represent this process, specifically with respect to the evaluation of systematic errors that can lead to inaccurate (biased) results (i.e. focusing on internal validity). Systematic review methods developed in the clinical medicine arena have been adapted for use in evaluating environmental health hazards; this expansion raises questions about the scope of risk of bias tools and the extent to which they capture the elements that can affect the interpretation of results from environmental and occupational epidemiology studies and in vivo animal toxicology studies, (the studies typically available for assessment of risk of chemicals). One such element, described here as "sensitivity", is a measure of the ability of a study to detect a true effect or hazard. This concept is similar to the concept of the sensitivity of an assay; an insensitive study may fail to show a difference that truly exists, leading to a false conclusion of no effect. Factors relating to study sensitivity should be evaluated in a systematic manner with the same rigor as the evaluation of other elements within a risk of bias framework. We discuss the importance of this component for the interpretation of individual studies, examine approaches proposed or in use to address it, and describe how it relates to other evaluation components. The evaluation domains contained within a risk of bias tool can include, or can be modified to include, some features relating to study sensitivity; the explicit inclusion of these sensitivity criteria with the same rigor and at the same stage of study evaluation as other bias-related criteria can improve the evaluation process. In some cases, these and other features may be better addressed through a separate sensitivity domain. The combined evaluation of risk of bias and

  17. Risk of sensitization and allergy in Ragweed workers – a pilot study

    PubMed Central

    2014-01-01

    Background Due to its high allergenic potential Ambrosia artemisiifolia has become a health threat in many European countries during the last few decades. Hence, several cities and communities initiated ragweed eradication campaigns. In Berlin, Germany, so-called Ambrosia scouts are being assigned the task of finding and eliminating this weed. We sought to evaluate the potential risk of sensitization and allergy in these individuals. Findings In order to assess the risk of sensitization and allergy, we followed-up 20 Ambrosia scouts by skin-prick test with inhalant allergens, immunoserological and pulmonary function tests. Additionally, medical conditions were evaluated by a questionnaire especially designed for this study. Despite close contact to ragweed over a median duration of 13.8 months, none of the participants became sensitized or allergic to ragweed. One individual developed a clinical non-relevant sensitization towards the taxiconomically-related plant mugwort. A decline in relative FEV1 was most probably due to heavy smoking. Conclusions Our surprising findings suggest that intensive contact and exposure to high ragweed pollen concentrations do not necessarily result in sensitization and/or allergy, meaning that the allergenic potential of this weed might be lower than hitherto expected. However, it is also conceivable that continuous exposure to high allergen levels induced tolerance in the ragweed workers. Due to the relatively small number of subjects studied, our results might be biased and therefore investigations on larger study groups are needed. PMID:25147570

  18. Theoretica Study of Asymmetric Double D-π-A Organic Sensitizers for Efficient Dye-Sensitized Solar Cells.

    PubMed

    Kwon, Dong Yuel; Lee, Gun Hyung; Kim, Young Sik

    2015-03-01

    Three novel dye sensitizers that were based on asymmetric double D-π-A chains with phenoxazine (POZ) and diphenylamine (DPA) as electron donors and cyanoacetic acid (CA) and 2-(1,1- dicyanomethylene) rhodanine (RD) as electron acceptors (DCPR, DRPC, DRPR) were designed, theoretically investigated, and compared with the reference dye based on asymmetric double D-π-A chains (DCPC). Using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations, we gained insight into the factors responsible for the photovoltaic properties of the dye sensitizers. Due to the different HOMO levels of each donor and the different LUMO levels of each acceptor, the absorption spectrum of each dye showed different shapes. Among the dyes, DRPR showed a broader and more bathochromically shifted absorption band than the other dies. It also showed a higher molar extinction coefficient than that of the reference dye (DCPC). This work suggests optimizing the chain of electron donors and acceptors in dye sensitizers based on asymmetric double D-π-A chains would produce good photovoltaic properties for dye-sensitized solar cells (DSSCs). PMID:26413690

  19. Importance analysis for Hudson River PCB transport and fate model parameters using robust sensitivity studies

    SciTech Connect

    Zhang, S.; Toll, J.; Cothern, K.

    1995-12-31

    The authors have performed robust sensitivity studies of the physico-chemical Hudson River PCB model PCHEPM to identify the parameters and process uncertainties contributing the most to uncertainty in predictions of water column and sediment PCB concentrations, over the time period 1977--1991 in one segment of the lower Hudson River. The term ``robust sensitivity studies`` refers to the use of several sensitivity analysis techniques to obtain a more accurate depiction of the relative importance of different sources of uncertainty. Local sensitivity analysis provided data on the sensitivity of PCB concentration estimates to small perturbations in nominal parameter values. Range sensitivity analysis provided information about the magnitude of prediction uncertainty associated with each input uncertainty. Rank correlation analysis indicated which parameters had the most dominant influence on model predictions. Factorial analysis identified important interactions among model parameters. Finally, term analysis looked at the aggregate influence of combinations of parameters representing physico-chemical processes. The authors scored the results of the local and range sensitivity and rank correlation analyses. The authors considered parameters that scored high on two of the three analyses to be important contributors to PCB concentration prediction uncertainty, and treated them probabilistically in simulations. They also treated probabilistically parameters identified in the factorial analysis as interacting with important parameters. The authors used the term analysis to better understand how uncertain parameters were influencing the PCB concentration predictions. The importance analysis allowed us to reduce the number of parameters to be modeled probabilistically from 16 to 5. This reduced the computational complexity of Monte Carlo simulations, and more importantly, provided a more lucid depiction of prediction uncertainty and its causes.

  20. Adjoint sensitivity studies of loop current and eddy shedding in the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Gopalakrishnan, Ganesh; Cornuelle, Bruce D.; Hoteit, Ibrahim

    2013-07-01

    Adjoint model sensitivity analyses were applied for the loop current (LC) and its eddy shedding in the Gulf of Mexico (GoM) using the MIT general circulation model (MITgcm). The circulation in the GoM is mainly driven by the energetic LC and subsequent LC eddy separation. In order to understand which ocean regions and features control the evolution of the LC, including anticyclonic warm-core eddy shedding in the GoM, forward and adjoint sensitivities with respect to previous model state and atmospheric forcing were computed using the MITgcm and its adjoint. Since the validity of the adjoint model sensitivities depends on the capability of the forward model to simulate the real LC system and the eddy shedding processes, a 5 year (2004-2008) forward model simulation was performed for the GoM using realistic atmospheric forcing, initial, and boundary conditions. This forward model simulation was compared to satellite measurements of sea-surface height (SSH) and sea-surface temperature (SST), and observed transport variability. Despite realistic mean state, standard deviations, and LC eddy shedding period, the simulated LC extension shows less variability and more regularity than the observations. However, the model is suitable for studying the LC system and can be utilized for examining the ocean influences leading to a simple, and hopefully generic LC eddy separation in the GoM. The adjoint sensitivities of the LC show influences from the Yucatan Channel (YC) flow and Loop Current Frontal Eddy (LCFE) on both LC extension and eddy separation, as suggested by earlier work. Some of the processes that control LC extension after eddy separation differ from those controlling eddy shedding, but include YC through-flow. The sensitivity remains stable for more than 30 days and moves generally upstream, entering the Caribbean Sea. The sensitivities of the LC for SST generally remain closer to the surface and move at speeds consistent with advection by the high-speed core of

  1. Study of the Intergranular Corrosion of Sensitized UNS S31803 Stainless Steel in Transpassive Region

    NASA Astrophysics Data System (ADS)

    Morshed Behbahani, Khashayar; Najafisayar, Pooria; Pakshir, Mahmoud

    2016-06-01

    In this study, intergranular corrosion behavior of UNS S31803 duplex stainless steel was investigated using conventional potentiodynamic polarization, double loop electrochemical potentiokinetic reactivation (DLEPR), and electrochemical impedance spectroscopy (EIS) technique carried out at different potentials in the transpassive region. Different types of heat treatments were used to obtain samples with different degrees of sensitization. The results of the DLEPR tests showed that the solution-annealed sample and that was sensitized for half an hour would be considered as nonsensitized ones. Moreover, the sample that was sensitized for 24 h exhibits the highest value of the degree of sensitization. Polarization test results showed a typical active-passive behavior from which the transpassive potential range was determined and used as the range of the applied DC bias in the EIS experiments. Three different AC responses (including capacitive and inductive responses) were observed depending on the value of applied DC bias in the EIS experiments. In addition, it was observed that the presence of the second inductive loop at high applied DC bias is due to the adsorption of nonsoluble corrosion products on the surface of the samples. Moreover, the fitted values to the charge transfer and polarization resistances (R ct and R P) decreased as the sensitization time increased from 30 min to 24 h. Such observations were in good accordance with the metallographic examination of the corroded surfaces, carried out by optical and scanning electron microscopy techniques, revealing discontinuous grain boundary attack in nonsensitized samples and a continuous network of grain boundary attack in the case of sensitized ones. Moreover, as the applied DC bias increases the ferrite phase attack also occurs in the sensitized samples. In addition, approximately no pitting corrosion was observed on the surface of the corroded samples which is in accordance with their respective cyclic

  2. The Effect of Nature Documentaries on Students' Environmental Sensitivity: A Case Study

    ERIC Educational Resources Information Center

    Barbas, Tasos A.; Paraskevopoulos, Stefanos; Stamou, Anastasia G.

    2009-01-01

    Despite the potential educational value of nature documentaries, the contribution of such films to environmental education is largely unknown. In the present study, we attempt to delineate the role of nature documentaries to the environmental sensitivity of students when the films are simply introduced to the class. More specifically, the present…

  3. Study of glass transition temperature (Tg) of novel stress-sensitive composites using molecular dynamic simulation

    NASA Astrophysics Data System (ADS)

    Koo, B.; Liu, Y.; Zou, J.; Chattopadhyay, A.; Dai, L. L.

    2014-09-01

    This study investigates the glass transition temperature (Tg) of novel stress-sensitive composites capable of detecting a damage precursor using molecular dynamics (MD) simulations. The molecular structures of a cross-linked epoxy network (which consist of epoxy resin, hardener and stress-sensitive material) have been simulated and experimentally validated. The chemical constituents of the molecular structures are di-glycidyl ether of bisphenol F (DGEBF: epoxy resin), di-ethylene tri-amine (DETA: hardener) and tris-(cinnamoyloxymethyl)-ethane (TCE: stress-sensitive material). The cross-linking degree is varied by manipulating the number of covalent bonds through tuning a cutoff distance between activated DGEBF and DETA during the non-equilibrium MD simulation. A relationship between the cross-linking degree and Tgs has been studied numerically. In order to validate a proposed MD simulation framework, MD-predicted Tgs of materials used in this study have been compared to the experimental results obtained by the differential scanning calorimetry (DSC). Two molecular models have been constructed for comparative study: (i) neat epoxy (epoxy resin with hardener) and (ii) smart polymer (neat epoxy with stress-sensitive material). The predicted Tgs show close agreement with the DSC results.

  4. Aggressive Behavior between Siblings and the Development of Externalizing Problems: Evidence from a Genetically Sensitive Study

    ERIC Educational Resources Information Center

    Natsuaki, Misaki N.; Ge, Xiaojia; Reiss, David; Neiderhiser, Jenae M.

    2009-01-01

    This study investigated the prospective links between sibling aggression and the development of externalizing problems using a multilevel modeling approach with a genetically sensitive design. The sample consisted of 780 adolescents (390 sibling pairs) who participated in 2 waves of the Nonshared Environment in Adolescent Development project.…

  5. Maternal Sensitivity and Child Secure Base Use in Early Childhood: Studies in Different Cultural Contexts

    ERIC Educational Resources Information Center

    Posada, German; Trumbell, Jill; Noblega, Magaly; Plata, Sandra; Peña, Paola; Carbonell, Olga A.; Lu, Ting

    2016-01-01

    This study tested whether maternal sensitivity and child security are related during early childhood and whether such an association is found in different cultural and social contexts. Mother-child dyads (N = 237) from four different countries (Colombia, Mexico, Peru, and the United States) were observed in naturalistic settings when children were…

  6. Predicting Changes in Cultural Sensitivity among Students of Spanish during Short-Term Study Abroad

    ERIC Educational Resources Information Center

    Martinsen, Rob

    2011-01-01

    Short-term study abroad programs of less than a semester are becoming increasingly popular among undergraduate students in the United States. However, little research has examined the changes in students' cultural sensitivity through their participation in such programs or what factors may predict growth and improvement in such areas. This study…

  7. Maternal sensitivity, infant limbic structure volume and functional connectivity: a preliminary study

    PubMed Central

    Rifkin-Graboi, A; Kong, L; Sim, L W; Sanmugam, S; Broekman, B F P; Chen, H; Wong, E; Kwek, K; Saw, S-M; Chong, Y-S; Gluckman, P D; Fortier, M V; Pederson, D; Meaney, M J; Qiu, A

    2015-01-01

    Mechanisms underlying the profound parental effects on cognitive, emotional and social development in humans remain poorly understood. Studies with nonhuman models suggest variations in parental care affect the limbic system, influential to learning, autobiography and emotional regulation. In some research, nonoptimal care relates to decreases in neurogenesis, although other work suggests early-postnatal social adversity accelerates the maturation of limbic structures associated with emotional learning. We explored whether maternal sensitivity predicts human limbic system development and functional connectivity patterns in a small sample of human infants. When infants were 6 months of age, 20 mother–infant dyads attended a laboratory-based observational session and the infants underwent neuroimaging at the same age. After considering age at imaging, household income and postnatal maternal anxiety, regression analyses demonstrated significant indirect associations between maternal sensitivity and bilateral hippocampal volume at six months, with the majority of associations between sensitivity and the amygdala demonstrating similar indirect, but not significant results. Moreover, functional analyses revealed direct associations between maternal sensitivity and connectivity between the hippocampus and areas important for emotional regulation and socio-emotional functioning. Sensitivity additionally predicted indirect associations between limbic structures and regions related to autobiographical memory. Our volumetric results are consistent with research indicating accelerated limbic development in response to early social adversity, and in combination with our functional results, if replicated in a larger sample, may suggest that subtle, but important, variations in maternal care influence neuroanatomical trajectories important to future cognitive and emotional functioning. PMID:26506054

  8. Maternal sensitivity, infant limbic structure volume and functional connectivity: a preliminary study.

    PubMed

    Rifkin-Graboi, A; Kong, L; Sim, L W; Sanmugam, S; Broekman, B F P; Chen, H; Wong, E; Kwek, K; Saw, S-M; Chong, Y-S; Gluckman, P D; Fortier, M V; Pederson, D; Meaney, M J; Qiu, A

    2015-01-01

    Mechanisms underlying the profound parental effects on cognitive, emotional and social development in humans remain poorly understood. Studies with nonhuman models suggest variations in parental care affect the limbic system, influential to learning, autobiography and emotional regulation. In some research, nonoptimal care relates to decreases in neurogenesis, although other work suggests early-postnatal social adversity accelerates the maturation of limbic structures associated with emotional learning. We explored whether maternal sensitivity predicts human limbic system development and functional connectivity patterns in a small sample of human infants. When infants were 6 months of age, 20 mother-infant dyads attended a laboratory-based observational session and the infants underwent neuroimaging at the same age. After considering age at imaging, household income and postnatal maternal anxiety, regression analyses demonstrated significant indirect associations between maternal sensitivity and bilateral hippocampal volume at six months, with the majority of associations between sensitivity and the amygdala demonstrating similar indirect, but not significant results. Moreover, functional analyses revealed direct associations between maternal sensitivity and connectivity between the hippocampus and areas important for emotional regulation and socio-emotional functioning. Sensitivity additionally predicted indirect associations between limbic structures and regions related to autobiographical memory. Our volumetric results are consistent with research indicating accelerated limbic development in response to early social adversity, and in combination with our functional results, if replicated in a larger sample, may suggest that subtle, but important, variations in maternal care influence neuroanatomical trajectories important to future cognitive and emotional functioning. PMID:26506054

  9. Study of node and mass sensitivity of resonant mode based cantilevers with concentrated mass loading

    SciTech Connect

    Zhang, Kewei Chai, Yuesheng; Fu, Jiahui

    2015-12-15

    Resonant-mode based cantilevers are an important type of acoustic wave based mass-sensing devices. In this work, the governing vibration equation of a bi-layer resonant-mode based cantilever attached with concentrated mass is established by using a modal analysis method. The effects of resonance modes and mass loading conditions on nodes and mass sensitivity of the cantilever were theoretically studied. The results suggested that the node did not shift when concentrated mass was loaded on a specific position. Mass sensitivity of the cantilever was linearly proportional to the square of the point displacement at the mass loading position for all the resonance modes. For the first resonance mode, when mass loading position x{sub c} satisfied 0 < x{sub c} < ∼ 0.3l (l is the cantilever beam length and 0 represents the rigid end), mass sensitivity decreased as the mass increasing while the opposite trend was obtained when mass loading satisfied ∼0.3l ≤ x{sub c} ≤ l. Mass sensitivity did not change when concentrated mass was loaded at the rigid end. This work can provide scientific guidance to optimize the mass sensitivity of a resonant-mode based cantilever.

  10. First Study on Phosphonite-Coordinated Ruthenium Sensitizers for Efficient Photocatalytic Hydrogen Evolution.

    PubMed

    Swetha, T; Mondal, Indranil; Bhanuprakash, K; Pal, Ujjwal; Singh, Surya Prakash

    2015-09-01

    For the first time we report the design and syntheses of phosphonite coordinated ruthenium(II) sensitizers bearing ĈN̂N ligand and/or terpyridine derivatives carboxylate anchor (GS11, GS12. and GS13) and its application for hydrogen production over Pt-TiO2 system. These heteroleptic complexes exhibit broad metal-to-ligand charge transfer transition band over the whole visible regime extending up to 900 nm. DFT calculations of these complexes show that the HOMO is distributed over the Ru and Cl atom whereas; LUMO is localized on the polypyridile ligand, which are anchored on TiO2 surface. Among the sensitizers tested for photocatalytic hydrogen evolution, GS12 exhibited a maximum turnover number (TON) 8605 (for 8 h), which is very high compared to the reference sensitizer (N719) with TON 163 under similar evaluation condition. The dependence of the hydrogen evolution rate at different pH using GS11, GS12, GS13, and DX-1-sensitized Pt-TiO2 has been studied and the maximum H2 production yield was obtained at pH 7 for all sensitizers. PMID:26280353

  11. Incidence and determinants of IgE-mediated sensitization in apprentices. A prospective study.

    PubMed

    Gautrin, D; Ghezzo, H; Infante-Rivard, C; Malo, J L

    2000-10-01

    We investigated prospectively the incidence and determinants of work-related specific skin sensitization in a cohort of 769 apprentices, including 417 in animal health technology, 230 in pastry-making, and 122 in dental-hygiene technology. Subjects were recruited when starting exposure to laboratory animals, flour, or latex. A questionnaire and skin-prick tests with common and work-related allergens were administered on entry and at follow-up visits from 8 to 44 mo; information on number of hours of exposure to specific allergens was obtained. Among 769 apprentices, 698 attended >/= 1 follow-up visit. A total of 111 subjects developed specific sensitization over the study period. The incidence of work-related sensitization (per person-year) was 8.9% (95% CI 7.3 to 11.0%) in the animal-health program, 4.2% (95% CI 1.8 to 8.2%) in the pastry-making program, and 2.5% (95% CI = 0.7 to 4.3%) in the dental-hygiene program. In the animal health group, Cox regression analyses showed that atopy, nasal, and respiratory symptoms in the pollen season, and exposure assessed by the school attended or by duration of exposure to rodents were the most significant predictors of sensitization. In the dental-hygiene program, atopy and asthma were significant determinants. This study shows that: (1) an apprenticeship in animal-health technology carries a greater risk of developing specific sensitization than do apprenticeships in pastry-making and dental-hygiene; (2) atopy, respiratory symptoms in the pollen season, and number of hours in contact with rodents determine the risk of sensitization in apprentices in the animal health program. PMID:11029321

  12. Mesoscale ensemble sensitivity analysis for predictability studies and observing network design in complex terrain

    NASA Astrophysics Data System (ADS)

    Hacker, Joshua

    2013-04-01

    Ensemble sensitivity analysis (ESA) is emerging as a viable alternative to adjoint sensitivity. Several open issues face ESA for forecasts dominated by mesoscale phenomena, including (1) sampling error arising from finite-sized ensembles causing over-estimated sensitivities, and (2) violation of linearity assumptions for strongly nonlinear flows. In an effort to use ESA for predictability studies and observing network design in complex terrain, we present results from experiments designed to address these open issues. Sampling error in ESA arises in two places. First, when hypothetical observations are introduced to test the sensitivity estimates for linearity. Here the same localization that was used in the filter itself can be simply applied. Second and more critical, localization should be considered within the sensitivity calculations. Sensitivity to hypothetical observations, estimated without re-running the ensemble, includes regression of a sample of a final-time (forecast) metric onto a sample of initial states. Derivation to include localization results in two localization coefficients (or factors) applied in separate regression steps. Because the forecast metric is usually a sum, and can also include a sum over a spatial region and multiple physical variables, a spatial localization function is difficult to specify. We present results from experiments to empirically estimate localization factors for ESA to test hypothetical observations for mesoscale data assimilation in complex terrain. Localization factors are first derived for an ensemble filter following the empirical localization methodology. Sensitivities for a fog event over Salt Lake City, and a Colorado downslope wind event, are tested for linearity by approximating assimilation of perfect observations at points of maximum sensitivity, both with and without localization. Observation sensitivity is then estimated, with and without localization, and tested for linearity. The validity of the

  13. Meta-analysis of genome-wide association studies identifies 10 loci influencing allergic sensitization

    PubMed Central

    Granell, Raquel; Strachan, David P; Alves, Alexessander Couto; Linneberg, Allan; Curtin, John A; Warrington, Nicole M; Standl, Marie; Kerkhof, Marjan; Jonsdottir, Ingileif; Bukvic, Blazenka K; Kaakinen, Marika; Sleimann, Patrick; Thorleifsson, Gudmar; Thorsteinsdottir, Unnur; Schramm, Katharina; Baltic, Svetlana; Kreiner-Møller, Eskil; Simpson, Angela; St Pourcain, Beate; Coin, Lachlan; Hui, Jennie; Walters, Eugene H; Tiesler, Carla M T; Duffy, David L; Jones, Graham; Ring, Susan M; McArdle, Wendy L; Price, Loren; Robertson, Colin F; Pekkanen, Juha; Tang, Clara S; Thiering, Elisabeth; Montgomery, Grant W; Hartikainen, Anna-Liisa; Dharmage, Shyamali C; Husemoen, Lise L; Herder, Christian; Kemp, John P; Elliot, Paul; James, Alan; Waldenberger, Melanie; Abramson, Michael J; Fairfax, Benjamin P; Knight, Julian C; Gupta, Ramneek; Thompson, Philip J; Holt, Patrick; Sly, Peter; Hirschhorn, Joel N; Blekic, Mario; Weidinger, Stephan; Hakonarsson, Hakon; Stefansson, Kari; Heinrich, Joachim; Postma, Dirkje S; Custovic, Adnan; Pennell, Craig E; Jarvelin, Marjo-Riitta; Koppelman, Gerard H; Timpson, Nicholas; Ferreira, Manuel A; Bisgaard, Hans; Henderson, A John

    2016-01-01

    Allergen-specific IgE (allergic sensitization) plays a central role in the pathogenesis of allergic disease. We performed the first large-scale genome wide association study (GWAS) of allergic sensitization in 5,789 affected individuals and 10,056 controls and followed up the top SNP from 26 loci in 6,114 affected individuals and 9,920 controls. We increased the number of susceptibility loci with genome-wide significant association to allergic sensitization from three to 10, including SNPs in or near TLR6, C11orf30, STAT6, SLC25A46, HLA-DQB1, IL1RL1, LPP, MYC, IL2 and HLA-B. All the top-SNPs were associated with allergic symptoms in an independent study. Risk variants at these 10 loci were estimated to account for at least 25% of allergic sensitization and allergic rhinitis. Understanding the molecular mechanisms underlying these associations may provide novel insight into the etiology of allergic disease. PMID:23817571

  14. Cosmetic Contact Sensitivity in Patients with Melasma: Results of a Pilot Study

    PubMed Central

    Prabha, Neel; Mahajan, Vikram K.; Mehta, Karaninder S.; Chauhan, Pushpinder S.

    2014-01-01

    Background. Some of the patients with melasma perhaps have pigmented cosmetic dermatitis. However, cosmetic contact sensitivity in melasma remains poorly studied particularly in the Indian context. Objectives. To study cosmetic contact sensitivity in patients with melasma. Materials and Methods. 67 (F : M = 55 : 12) consecutive patients with melasma between 19 and 49 years of age were patch tested sequentially during January–December, 2012, with Indian Cosmetic and Fragrance Series, Indian Sunscreen Series, p-phenylenediamine, and patient's own cosmetic products. Results. 52 (78%) patients were in the age group of 20–40 years. The duration of melasma varied from 1 month to 20 years. Centrofacial, malar, and mandibular patterns were observed in 48 (72%), 18 (27%), and 1 (1%) patients, respectively. Indian Cosmetics and Fragrance Series elicited positive reactions in 29 (43.3%) patients. Cetrimide was the most common contact sensitizers eliciting positivity in 15 (52%) patients, followed by gallate mix in 9 (31%) patients and thiomersal in 7 (24%) patients. Only 2 of the 42 patients showed positive reaction from their own cosmetics while the other 5 patients had irritant reaction. Indian Sunscreen Series did not elicit any positive reaction. Conclusion. Cosmetics contact sensitivity appears as an important cause of melasma not associated with pregnancy, lactation, or hormone therapy. PMID:25132846

  15. The sensitizing capacity of naturally occurring quinones. Experimental studies in guinea pigs. II. Benzoquinones.

    PubMed

    Schulz, K H; Garbe, I; Hausen, B M; Simatupang, M H

    1979-05-01

    Experimental studies on the sensitizing capacity of naturally occurring benzoquinones, isolated from plants and woods have been carried out in guinea pigs of the Pirbright white strain. Seven compounds were available: primin, three dalbergiones, mansonia quinone (mansonone A), 2,6-dimethoxybenzoquinone and rapanone. With five of these substances (primin, mansonone A, three dalbergiones) guinea pigs could be sensitized. Primin, the allergen of Primula obconica Hance (primrose) proved to be the most effective one of all quinones tested in this and the preceding studies. As a similar but weaker sensitizer R-3, 4-dimethoxydalbergione from Machaerium scleroxylon Tul. (Pao ferro, Caviuna vermelha) could be identified. The results obtained with mansonone A, a sesquiterpenoid quinone from Mansonia altissima A. Chev. demonstrate that even naturally occurring orthoquinones are capable of inducing contact allergy. Allergic cross reactions could be obtained between all chemically related mansonones A-F. The results are in good accordance with the view that the sensitizing capacity of naturally occurring quinones depends on the fundamental quinoid structure and the length, position and configuration of the aliphatic side-chain. PMID:464645

  16. Does a culturally sensitive smoking prevention program reduce smoking intentions among Aboriginal children? A pilot study.

    PubMed

    McKennitt, Daniel W; Currie, Cheryl L

    2012-01-01

    The aim of the study was to determine if a culturally sensitive smoking prevention program would have short-term impacts on smoking intentions among Aboriginal children. Two schools with high Aboriginal enrollment were selected for the study. A grade 4 classroom in one school was randomly assigned to receive the culturally sensitive smoking prevention program. A grade 4 classroom in the second school received a standard smoking prevention program delivered in this jurisdiction. Children in each classroom were tested pre- and post-intervention to measure attitude changes about smoking. There was a significant reduction in intentions to smoke among Aboriginal children who received the culturally sensitive smoking prevention program. The small overall sample size precluded a direct comparison of the efficacy of the culturally sensitive and standard programs. The present findings suggest a smoking prevention program that has been culturally adapted for Aboriginal children may reduce future smoking intentions among Aboriginal grade 4 students. Further research is needed to determine the extent to which school smoking prevention programs adapted to respect the long-standing use of tobacco in Aboriginal cultural traditions may be more effective than standard programs in reaching Aboriginal youth. PMID:22875472

  17. Sensitization to silk allergen among workers of silk filatures in India: a comparative study

    PubMed Central

    Gowda, Giriyanna; Vijayeendra, Anagha Manakari; Sarkar, Nivedita; Nagaraj, Chitra; Masthi, Nugehally Raju Ramesh

    2016-01-01

    Background Sericulture plays an eminent role in development of rural economy in India. Silk filature is a unit where silk is unwound from the cocoons and the strands are collected into skeins. During the process workers are exposed to the high molecular weight proteins like Sericin and Fibroin which are potent allergens leading to sensitization over a period of time and subsequently occupational related health disorders. Objective To identify and compare the magnitude of silk allergen sensitization in workers of silk filatures. Methods A community based comparative descriptive study was conducted for a period of 1 year at Ramanagara in south India. One hundred twenty subjects working in the silk filatures formed the study group. For comparison, 2 types of controls were selected viz.120 subjects who were not working in the silk filatures but resided in the same geographical area (control A) and 360 subjects who were not working in silk filatures as well not residing in the same geographical area (control B). Skin prick test was used to identify the silk allergen sensitization. Results Mean age was 34.14 ± 2.84 years in the study group. Mean age was 40.59 ± 14.40 years and 38.54 ± 12.20 years in control A and control B, respectively. There were 35 males (29.16%) and 85 females (70.84%) in the study group. There were 58 (48.34%) males and 62 (51.66%) females and 152 (42.2%) males and 208 females (57.8%) in control A and control B, respectively. Sensitization to silk allergen was 35.83% in the study group and 20.83% in the control group A and 11.11% in control group B. There was difference in the allergen sensitivity between the study group and control groups and it was statistically significant (chi-square = 38.08; p < 0.001). Conclusion There is high burden of silk allergen sensitization among silk filature workers. PMID:27141481

  18. Wheat sensitization and work-related symptoms in the baking industry are preventable. An epidemiologic study.

    PubMed

    Houba, R; Heederik, D; Doekes, G

    1998-11-01

    A cross-sectional study was conducted among 393 workers from 21 bakeries to study the relationship between wheat allergen exposure and wheat sensitization and work-related allergic symptoms. Exposure to wheat allergens was characterized by a recently developed and validated immunoassay. Specific IgE antibodies against wheat flour and common allergens were measured by immunoassays, and work-related allergic symptoms were registered by questionnaire. A strong and positive association was found between wheat flour allergen exposure and wheat flour sensitization. This relationship was steepest and strongest in atopics. Prevalence ratios for high and medium wheat allergen exposure were 5.2 (95% confidence interval [CI], 1.6-16.2), and 2.7 (0.5-14.5) for atopic workers, and 2.5 (0.8-7.5) and 1.4 (0. 3-6.4) for nonatopics, compared with workers with low wheat allergen exposure. In sensitized bakers those with an elevated allergen exposure had more often work-related symptoms, with prevalence ratios for high and medium wheat allergen exposure of 3.5 (CI 1.6-7. 5) and 2.6 (CI 0.9-7.8), respectively, compared with workers with low wheat allergen exposure. The existence of exposure-sensitization gradients suggests that work-related sensitization risk will be negligible when exposure levels will be reduced to average exposure concentration of 0.2 microgram/m3 wheat allergen or approximately 0.5 mg/m3 inhalable dust during a work shift. PMID:9817699

  19. A study of the enhanced sensitizing capacity of a contact allergen in lipid vesicle formulations

    SciTech Connect

    Simonsson, Carl; Madsen, Jakob Torp; Graneli, Annette; Andersen, Klaus E.; Karlberg, Ann-Therese; Jonsson, Charlotte A.; Ericson, Marica B.

    2011-05-01

    The growing focus on nanotechnology and the increased use of nano-sized structures, e.g. vesicles, in topical formulations has led to safety concerns. We have investigated the sensitizing capacity and penetration properties of a fluorescent model compound, rhodamine B isothiocyanate (RBITC), when administered in micro- and nano-scale vesicle formulations. The sensitizing capacity of RBITC was studied using the murine local lymph node assay (LLNA) and the skin penetration properties were compared using diffusion cells in combination with two-photon microscopy (TPM). The lymph node cell proliferation, an indicator of a compounds sensitizing capacity, increased when RBITC was applied in lipid vesicles as compared to an ethanol:water (Et:W) solution. Micro-scale vesicles showed a slightly higher cell proliferative response compared to nano-scale vesicles. TPM imaging revealed that the vesicle formulations improved the skin penetration of RBITC compared to the Et:W solution. A strong fluorescent region in the stratum corneum and upper epidermis implies elevated association of RBITC to these skin layers when formulated in lipid vesicles. In conclusion, the results indicate that there could be an elevated risk of sensitization when haptens are delivered in vehicles containing lipid vesicles. Although the size of the vesicles seems to be of minor importance, further studies are needed before a more generalized conclusion can be drawn. It is likely that the enhanced sensitizing capacity is a consequence of the improved penetration and increased formation of hapten-protein complexes in epidermis when RBITC is delivered in ethosomal formulations. - Graphical Abstract: Display Omitted

  20. Critical analysis of studies concerning reports of respiratory sensitization to certain wood dusts.

    PubMed

    Williams, P Brock

    2005-01-01

    Studies have been published reporting that exposures to certain wood dusts are sensitizing, resulting in respiratory symptoms in susceptible individuals. Many of the publications in this field are case reports that collectively have a number of important shortcomings. Illuminating these should further our understanding of whether respiratory sensitization results from occupational exposure to particular wood dusts. The aim of this study was to critically review and understand the evidence to date regarding reported respiratory sensitization in connection with wood dusts from oak, beech, pine, ash, and western red cedar. Publications dealing with these commercially important woods in North America have been selected from the Pubmed/Medline database (1966 to the present) using the key word, wood dust. These articles, along with supporting references on procedures and techniques, are reviewed according to the strengths and weaknesses of evidence and conclusions presented. Evidence from skin testing, specific immunoglobulin E measurements, and basophil histamine release tests suggests that reported symptoms are not likely to be immunologically derived. Because of methodological problems, challenge tests with specific wood dusts do not support the conclusion that reactions to certain wood dusts are specific. Experiments with nonspecific bronchoconstrictive agents indicate that a number of study subjects possess hyperresponsive airways. Thus, select individuals can demonstrate various respiratory symptoms in the woodworking industry, but any specificity or direct cause is currently unproved. Current studies do not support that exposure to wood dusts from a number of common North American wood species causes immunologic sensitization in woodworkers. Rather, symptoms reported in some studies of exposed workers seem to follow the paradigm for nonspecific respiratory responses in individuals with hyperresponsive airways. PMID:16270718

  1. A sensitivity study of weather data inaccuracies on evaporation duct height algorithms

    NASA Astrophysics Data System (ADS)

    Cook, John

    1991-05-01

    The sensitivity of five evaporation duct height algorithms to errors in shipboard meteorological data is examined, and the algorithms are intercompared. The data set used was generated parametrically so a large variation of environmental conditions could be considered. The errors in the meteorological data consisted of two types: uncorrelated random errors associated with sensor inaccuracies and both random and systematic errors due to the influence of ship-induced distortions. Before considering any errors, however, algorithm-to-algorithm differences of 10%-70% in the computed duct height are demonstrated and related to the assumptions and simplifications used during algorithm development. The sensitivity study shows that although the evaporation duct height algorithms have different genealogies, they have similar sensitivities. The sensitivities to errors caused by sensor inaccuracies range from 10% to 50% relative uncertainty in the calculated duct height, except for extremely low duct heights where the uncertainties are greater. During the daytime the relative uncertainties due to errors caused by ship-induced distortions are approximately 10%-20% higher than those due to the sensor errors, and they are about 50%-75% smaller at night because of a lack of solar heating of the ship. These conclusions represent a best-case scenario for Navy operational applications because of the omission of some sources of error, the optimistic ship error characteristics used, and the assumption of horizontal homogeneity in the near-surface refractivity field.

  2. Time-Resolved Study on Xanthene Dye-Sensitized Carbon Nitride Photocatalytic Systems.

    PubMed

    Zhang, Huiyu; Li, Shuang; Lu, Rong; Yu, Anchi

    2015-10-01

    Dye sensitization is a promising strategy to extend the visible light absorption of carbon nitride (C3N4) and increase the photocatalytic hydrogen evolution efficiency of C3N4 under visible light irradiation. However, the interaction dynamics between C3N4 and a sensitized dye has not been reported in the literature. Herein, we selected four commonly used xanthene dyes such as fluorescein, dibromofluorescein, eosin Y, and erythrosine B and prepared their corresponding dye-sensitized-C3N4 composites. For the first time, we derived the electron transfer rate from the LUMO of each photoexcited xanthene dye to the conduction band of C3N4 using picoesecond time-resolved fluorescence measurements. We also obtained the reduction potentials of all selected xanthene dyes and C3N4 with cyclic voltammetry measurements. The cyclic voltammetry measurements gave a consistent result with the picosecond time-resolved fluorescence measurements. Besides, the possibility of the selected xanthene dye as an acceptor for the hole of the photoexcited C3N4 was also discussed. We believe this study is significant for the researcher to understanding the fundamental aspects in the xanthene dye-sensitized-C3N4 photocatalytic systems. PMID:26389679

  3. Maternal Sensitivity and Child Secure Base Use in Early Childhood: Studies in Different Cultural Contexts.

    PubMed

    Posada, German; Trumbell, Jill; Noblega, Magaly; Plata, Sandra; Peña, Paola; Carbonell, Olga A; Lu, Ting

    2016-01-01

    This study tested whether maternal sensitivity and child security are related during early childhood and whether such an association is found in different cultural and social contexts. Mother-child dyads (N = 237) from four different countries (Colombia, Mexico, Peru, and the United States) were observed in naturalistic settings when children were between 36 and 72 months of age. Maternal and child behavior during interactions at home and in the playground were described using Q methodology. Findings reveal that across cultures, concurrent maternal sensitivity and more specific behavioral domains of maternal care (e.g., contributions to harmonious interactions and secure base support) are important for children's attachment security during early childhood. Implications for the study of attachment relationships beyond infancy and in diverse contexts are highlighted. PMID:26525825

  4. Alignment and Polarization Sensitivity Study on the Cassini: CIRS FIR Interferometer

    NASA Technical Reports Server (NTRS)

    Crooke, Julie; Hagopian, John

    1998-01-01

    The Composite InfraRed Spectrometer (CIRS) instrument flying on the Cassini spacecraft to Saturn is a cryogenic spectrometer with far-infrared (FIR) and mid-infrared (MIR) channels. The CIRS FIR channel is a polarizing interferometer that contains three polarizing grid components. These components are an input polarizer, a polarizing beamsplitter, and an output polarizer/analyzer. They consist of a 1.5 micron thick mylar substrate with 2 microns wide copper wires, with 2 microns spacing (4 microns pitch) photolithographically deposited on the substrate. This paper details the alignment sensitivity studies performed on the polarizing beamsplitter, and the polarization sensitivity studies performed on all three polarizing components in the FIR interferometer.

  5. A Novel Touch-Sensitive Apparatus for Behavioral Studies in Unrestrained Squirrel Monkeys

    PubMed Central

    Kangas, Brian D.; Bergman, Jack

    2012-01-01

    Despite the increasing sophistication and affordability of touch-sensitive technology, its use in the behavioral sciences has been limited. The present paper describes the design and empirical validation of a novel touch-sensitive operant conditioning chamber for use with unrestrained squirrel monkeys. In addition, results from a variant of a commonly employed animal model of learning, the repeated acquisition task, demonstrated the effectiveness of this chamber in programming an assay of complex behavior. Finally, results from a study with Δ9-tetrahyrdrocannabinol, the active ingredient in marijuana, showed that its effects in this novel touchscreen chamber were consistent with its dose-related effects on learning using more conventional approaches. Overall, these studies indicate the touchscreen apparatus provides effective means for programming complex behavioral tasks to assess the effects of pharmacological agents on cognitive function. PMID:22790109

  6. N Reactor core heatup sensitivity study for the 32-inch unit cell model

    SciTech Connect

    Martin, F.; Zimmerman, B.; Heard, F.

    1988-02-01

    A number of N Reactor core heatup studies have been performed using the TRUMP-BD computer code. These studies were performed to address questions concerning the dependency of results on potential variations in the material properties and/or modeling assumptions. This report described and documents a series of 31 TRUMP-BD runs that were performed to determine the sensitivity of calculated inner-fuel temperatures to a variety of TRUMP input parameters and also to a change in the node density in a high-temperature-gradient region. The results of this study are based on the 32-in. model. 18 refs., 17 figs., 2 tab.

  7. First principles DFT study of dye-sensitized CdS quantum dots

    SciTech Connect

    Jain, Kalpna; Singh, Kh. S.; Kishor, Shyam; Josefesson, Ida; Odelius, Michael; Ramaniah, Lavanya M.

    2014-04-24

    Dye-sensitized quantum dots (QDs) are considered promising candidates for dye-sensitized solar cells. In order to maximize their efficiency, detailed theoretical studies are important. Here, we report a first principles density functional theory (DFT) investigation of experimentally realized dye - sensitized QD / ligand systems, viz., Cd{sub 16}S{sub 16}, capped with acetate molecules and a coumarin dye. The hybrid B3LYP functional and a 6−311+G(d,p)/LANL2dz basis set are used to study the geometric, energetic and electronic properties of these clusters. There is significant structural rearrangement in all the clusters studied - on the surface for the bare QD, and in the positions of the acetate / dye ligands for the ligated QDs. The density of states (DOS) of the bare QD shows states in the band gap, which disappear on surface passivation with the acetate molecules. Interestingly, in the dye-sensitised QD, the HOMO is found to be localized mainly on the dye molecule, while the LUMO is on the QD, as required for photo-induced electron injection from the dye to the QD.

  8. Assessment of musculoskeletal pain sensitivity and temporal summation by cuff pressure algometry: a reliability study.

    PubMed

    Graven-Nielsen, Thomas; Vaegter, Henrik Bjarke; Finocchietti, Sara; Handberg, Gitte; Arendt-Nielsen, Lars

    2015-11-01

    Chronic musculoskeletal pain is linked with sensitization, and standardized methods for assessment are needed. This study investigated (1) the test-retest reliability of computer-controlled cuff-pressure algometry (pain thresholds and temporal pain summation) on the arm and leg and (2) conditioned pain modulation (CPM) assessed by cuff algometry. The influences of age and gender were evaluated. On 2 different days, cuff pain threshold (cPPT), cuff pain tolerance (cPTT), and temporal summation of pain (TSP) by visual analog scale scores to 10 repeated cuff stimulations at cPTT intensity, as well as pressure pain threshold with handheld pressure algometry, were assessed in 136 healthy subjects. In one session, cuff pain sensitivity was also assessed before and after cold pressor-induced CPM. Good-to-excellent intraclass correlations (0.60-0.90) were demonstrated for manual and cuff algometry, and no systematic bias between sessions was found for cPPT, cPTT, and TSP on the leg and for cPTT and TSP on the arm. Cuff pressure pain threshold and cPTT were higher in men compared with women (P < 0.05). Middle-aged subjects had higher pressure pain threshold, but lower cPPT and cPTT, compared with younger subjects (P < 0.05). Temporal summation of pain was increased in women compared with men (P < 0.05). Cuff algometry was sensitive to CPM demonstrated as increased cPPT and cPTT and reduced TSP (P < 0.05). Reliability and sensitivity of computer-controlled cuff algometry for pain assessment is comparable with manual pressure algometry and constitutes a user-independent method for assessment of pain. Difference in age-related pain sensitivity between manual and cuff algometry should be further investigated. PMID:26172551

  9. Study on an auto-correlation-function-based damage index: Sensitivity analysis and structural damage detection

    NASA Astrophysics Data System (ADS)

    Zhang, Muyu; Schmidt, Rüdiger

    2015-12-01

    The damage index based on the auto correlation function to detect the damage of the structure under white noise excitation is studied in detail in this paper. The maximum values of the auto correlation function of the vibration response signals (displacement, velocity and acceleration) from different measurement points of the structure are collected and formulated as a vector called Auto Correlation Function at Maximum Point Value Vector (AMV), which is expressed as a weighted combination of the Hadamard product of two mode shapes. AMV is normalized by its root mean square value so that the influence of the excitation can be eliminated. Sensitivity analysis for the different parts of the normalized AMV shows that the sensitivity of the normalized AMV to the local stiffness is dependent most on the sensitivity of the Hadamard product of the two lower order mode shapes to the local stiffness, which has a sudden change of the value around the local stiffness change position. The sensitivity of the normalized AMV has the similar shape and same trend that shows it is a very good damage indicator even for the very small damage. The relative change of the normalized AMV before and after damage occurs in the structure is adopted as the damage index to show the damage location. Several examples of the stiffness reduction detection of a 12-story shear frame structure are utilized to validate the results in sensitivity analysis, illustrate the effectiveness and anti-noise ability of the AMV-based damage detection method and compare the effect of the response type on the detectability of the normalized AMV.

  10. Evaluation of Pre-Transplant Panel Reactive Antibody Levels and Sensitization: A Single-Center Study.

    PubMed

    Can, Özgür; Gökçe, Ali Murat; Canbakan, Mustafa; Ata, Pınar; Şahin, Gülizar Manga; Titiz, Mesut İzzet; Apaydın, Süheyla

    2016-01-01

    BACKGROUND Sensitization is one of the most important barriers against transplantation. Our aim was to evaluate the sensitization status of our patients awaiting cadaveric transplantation and to identify factors causing sensitization. MATERIAL AND METHODS A total of 140 patients on the cadaveric waiting list during January 2014 were included in this retrospective cross-sectional study. The parametric t-test and the non-parametric chi-square test were used to detect differences between PRA-positive and -negative patients. Multivariate analysis was used to identify factors associated with PRA positivity. One-way analysis of variance was used to compare PRA-negative and -positive results. RESULTS Anti-HCV positivity (p=0.040), history of transfusion (p=0.041), and mean number of blood product transfused (p=0.047) were significantly related to class 1 PRA positivity. History of transfusion (p=0.038) and mean number of blood product transfused (p=0.044) were related to class 2 PRA positivity. The multivariate analysis indicated that transfusion and more than 5 units of blood product transfused were related to either class 1 or class 2 PRA positivity. No associations were found between PRA positivity and pregnancy, transplantation, age, sex, infection, abortion, cardiovascular disease, diabetes mellitus, hepatitis B, or time spent on dialysis and being on the transplantation waiting list. CONCLUSIONS Anti-HCV positivity and transfusion are risk factors for sensitization. Particular emphasis should be given to sensitization and its prevention to reduce waiting time for transplantation. PMID:27618946

  11. A case study for evaluating potential soil sensitivity in aridland systems.

    PubMed

    Peterman, Wendy L; Ferschweiler, Ken

    2016-04-01

    Globally, ecosystems are subjected to prolonged droughts and extreme heat events, leading to forest die-offs and dominance shifts in vegetation. Some scientists and managers view soil as the main resource to be considered in monitoring ecosystem responses to aridification. As the medium through which precipitation is received, stored, and redistributed for plant use, soil is an important factor in the sensitivity of ecosystems to a drying climate. This study presents a novel approach to evaluating where on a landscape soils may be most sensitive to drying, making them less resilient to disturbance, and where potential future vegetation changes could lead to such disturbance. The drying and devegetation of arid lands can increase wind erosion, contributing to aerosol and dust emissions. This has implications for air quality, human health, and water resources. This approach combines soil data with vegetation simulations, projecting future vegetation change, to create maps of potential areas of concern for soil sensitivity and dust production in a drying climate. Consistent with recent observations, the projections show shifts from grasslands and woodlands to shrublands in much of the southwestern region. An increase in forested area occurs, but shifts in the dominant types and spatial distribution of the forests also are seen. A net increase in desert ecosystems in the region and some changes in alpine and tundra ecosystems are seen. Approximately 124,000 km(2) of soils flagged as "sensitive" are projected to have vegetation change between 2041 and 2050, and 82,927 km(2) of soils may become sensitive because of future vegetation changes. These maps give managers a way to visualize and identify where soils and vegetation should be investigated and monitored for degradation in a drying climate, so restoration and mitigation strategies can be focused in these areas. PMID:26272449

  12. Numerical modeling of stress in stenotic arteries with microcalcifications: a parameter sensitivity study.

    PubMed

    Wenk, Jonathan F

    2011-01-01

    As a follow-up to the work presented in Wenk et al. (2010, "Numerical Modeling of Stress in Stenotic Arteries With Microcalcifications: A Micromechanical Approximation," ASME J. Biomech. Eng., 132, p. 091011), a formal sensitivity study was conducted in which several model parameters were varied. The previous work only simulated a few combinations of the parameters. In the present study, the fibrous cap thickness, longitudinal position of the region of microcalcifications, and volume fraction of microcalcifications were varied over a broader range of values. The goal of the present work is to investigate the effects of localized regions of microcalcifications on the stress field of atherosclerotic plaque caps in a section of carotid artery. More specifically, the variations in the magnitude and location of the maximum circumferential stress were assessed for a range of parameters using a global sensitivity analysis method known as Sobol' indices. The stress was calculated by performing finite element simulations of three-dimensional fluid-structure interaction models, while the sensitivity indices were computed using a Monte Carlo scheme. The results indicate that cap thickness plays a significant role in the variation in the magnitude of the maximum circumferential stress, with the sensitivity to volume fraction increasing when the region of microcalcification is located at the shoulder. However, the volume fraction played a larger role in the variation in the location of the maximum circumferential stress. This matches the finding of the previous study (Wenk et al., 2010, "Numerical Modeling of Stress in Stenotic Arteries With Microcalcifications: A Micromechanical Approximation," ASME J. Biomech. Eng., 132, p. 091011), which indicates that the maximum circumferential stress always shifts to the region of microcalcification. PMID:21186905

  13. Sensitivity and uncertainty in crop water footprint accounting: a case study for the Yellow River basin

    NASA Astrophysics Data System (ADS)

    Zhuo, L.; Mekonnen, M. M.; Hoekstra, A. Y.

    2014-06-01

    Water Footprint Assessment is a fast-growing field of research, but as yet little attention has been paid to the uncertainties involved. This study investigates the sensitivity of and uncertainty in crop water footprint (in m3 t-1) estimates related to uncertainties in important input variables. The study focuses on the green (from rainfall) and blue (from irrigation) water footprint of producing maize, soybean, rice, and wheat at the scale of the Yellow River basin in the period 1996-2005. A grid-based daily water balance model at a 5 by 5 arcmin resolution was applied to compute green and blue water footprints of the four crops in the Yellow River basin in the period considered. The one-at-a-time method was carried out to analyse the sensitivity of the crop water footprint to fractional changes of seven individual input variables and parameters: precipitation (PR), reference evapotranspiration (ET0), crop coefficient (Kc), crop calendar (planting date with constant growing degree days), soil water content at field capacity (Smax), yield response factor (Ky) and maximum yield (Ym). Uncertainties in crop water footprint estimates related to uncertainties in four key input variables: PR, ET0, Kc, and crop calendar were quantified through Monte Carlo simulations. The results show that the sensitivities and uncertainties differ across crop types. In general, the water footprint of crops is most sensitive to ET0 and Kc, followed by the crop calendar. Blue water footprints were more sensitive to input variability than green water footprints. The smaller the annual blue water footprint is, the higher its sensitivity to changes in PR, ET0, and Kc. The uncertainties in the total water footprint of a crop due to combined uncertainties in climatic inputs (PR and ET0) were about ±20% (at 95% confidence interval). The effect of uncertainties in ET0was dominant compared to that of PR. The uncertainties in the total water footprint of a crop as a result of combined key input

  14. Contributions to Future Stratospheric Climate Change: An Idealized Chemistry-Climate Model Sensitivity Study

    NASA Technical Reports Server (NTRS)

    Hurwitz, M. M.; Braesicke, P.; Pyle, J. A.

    2010-01-01

    Within the framework of an idealized model sensitivity study, three of the main contributors to future stratospheric climate change are evaluated: increases in greenhouse gas concentrations, ozone recovery, and changing sea surface temperatures (SSTs). These three contributors are explored in combination and separately, to test the interactions between ozone and climate; the linearity of their contributions to stratospheric climate change is also assessed. In a simplified chemistry-climate model, stratospheric global mean temperature is most sensitive to CO2 doubling, followed by ozone depletion, then by increased SSTs. At polar latitudes, the Northern Hemisphere (NH) stratosphere is more sensitive to changes in CO2, SSTs and O3 than is the Southern Hemisphere (SH); the opposing responses to ozone depletion under low or high background CO2 concentrations, as seen with present-day SSTs, are much weaker and are not statistically significant under enhanced SSTs. Consistent with previous studies, the strength of the Brewer-Dobson circulation is found to increase in an idealized future climate; SSTs contribute most to this increase in the upper troposphere/lower stratosphere (UT/LS) region, while CO2 and ozone changes contribute most in the stratosphere and mesosphere.

  15. Association of oxidative status and insulin sensitivity in periparturient dairy cattle: an observational study.

    PubMed

    Abuelo, A; Hernández, J; Benedito, J L; Castillo, C

    2016-04-01

    Post-parturient insulin resistance (IR) is a common feature in all mammalian animals. However, in dairy cows, it can be exacerbated because of high milk yield, leading to excessive negative energy balance, which is related with increased disease incidence, reduced milk production and worsened reproductive performance. IR has been extensively investigated in humans suffering from diabetes mellitus. In these subjects, it is known that oxidative stress (OS) plays a causative role in the onset of IR. Although OS occurs in transitional dairy cattle, there are yet no studies that investigated the association between IR and OS in dairy cattle. Therefore, the aim of this study was to investigate whether there is a relationship between OS and IR in dairy cattle. Serum samples were taken repeatedly from 22 dairy cows from 2 months prior to the expected calving date to 2 months after calving and were analysed for markers of metabolic and redox balance. Surrogate indices of insulin sensitivity were also calculated. Generalised linear mixed models revealed an effect of the oxidative status on peripheral insulin concentration and on indices of insulin sensitivity. Hence, field trials should investigate the effectiveness of antioxidant therapy on insulin sensitivity in peripheral tissues during the transition period of dairy cattle. PMID:26174108

  16. Thermal performance sensitivity studies in support of material modeling for extended storage of used nuclear fuel

    SciTech Connect

    Cuta, Judith M.; Suffield, Sarah R.; Fort, James A.; Adkins, Harold E.

    2013-08-15

    The work reported here is an investigation of the sensitivity of component temperatures of a storage system, including fuel cladding temperatures, in response to age-related changes that could degrade the design-basis thermal behavior of the system. Three specific areas of interest were identified for this study. • degradation of the canister backfill gas from pure helium to a mixture of air and helium, resulting from postulated leakage due to stress corrosion cracking (SCC) of canister welds • changes in surface emissivity of system components, resulting from corrosion or other aging mechanisms, which could cause potentially significant changes in temperatures and temperature distributions, due to the effect on thermal radiation exchange between components • changes in fuel and basket temperatures due to changes in fuel assembly position within the basket cells in the canister The purpose of these sensitivity studies is to provide a realistic example of how changes in the physical properties or configuration of the storage system components can affect temperatures and temperature distributions. The magnitudes of these sensitivities can provide guidance for identifying appropriate modeling assumptions for thermal evaluations extending long term storage out beyond 50, 100, 200, and 300 years.

  17. Preliminary Thermal-Mechanical Sizing of Metallic TPS: Process Development and Sensitivity Studies

    NASA Technical Reports Server (NTRS)

    Poteet, Carl C.; Abu-Khajeel, Hasan; Hsu, Su-Yuen

    2002-01-01

    The purpose of this research was to perform sensitivity studies and develop a process to perform thermal and structural analysis and sizing of the latest Metallic Thermal Protection System (TPS) developed at NASA LaRC (Langley Research Center). Metallic TPS is a key technology for reducing the cost of reusable launch vehicles (RLV), offering the combination of increased durability and competitive weights when compared to other systems. Accurate sizing of metallic TPS requires combined thermal and structural analysis. Initial sensitivity studies were conducted using transient one-dimensional finite element thermal analysis to determine the influence of various TPS and analysis parameters on TPS weight. The thermal analysis model was then used in combination with static deflection and failure mode analysis of the sandwich panel outer surface of the TPS to obtain minimum weight TPS configurations at three vehicle stations on the windward centerline of a representative RLV. The coupled nature of the analysis requires an iterative analysis process, which will be described herein. Findings from the sensitivity analysis are reported, along with TPS designs at the three RLV vehicle stations considered.

  18. A hierarchical Bayesian approach to adaptive vision testing: A case study with the contrast sensitivity function

    PubMed Central

    Gu, Hairong; Kim, Woojae; Hou, Fang; Lesmes, Luis Andres; Pitt, Mark A.; Lu, Zhong-Lin; Myung, Jay I.

    2016-01-01

    Measurement efficiency is of concern when a large number of observations are required to obtain reliable estimates for parametric models of vision. The standard entropy-based Bayesian adaptive testing procedures addressed the issue by selecting the most informative stimulus in sequential experimental trials. Noninformative, diffuse priors were commonly used in those tests. Hierarchical adaptive design optimization (HADO; Kim, Pitt, Lu, Steyvers, & Myung, 2014) further improves the efficiency of the standard Bayesian adaptive testing procedures by constructing an informative prior using data from observers who have already participated in the experiment. The present study represents an empirical validation of HADO in estimating the human contrast sensitivity function. The results show that HADO significantly improves the accuracy and precision of parameter estimates, and therefore requires many fewer observations to obtain reliable inference about contrast sensitivity, compared to the method of quick contrast sensitivity function (Lesmes, Lu, Baek, & Albright, 2010), which uses the standard Bayesian procedure. The improvement with HADO was maintained even when the prior was constructed from heterogeneous populations or a relatively small number of observers. These results of this case study support the conclusion that HADO can be used in Bayesian adaptive testing by replacing noninformative, diffuse priors with statistically justified informative priors without introducing unwanted bias. PMID:27105061

  19. Case study sensitivity analysis of transmission spectra for water contaminant monitoring

    NASA Astrophysics Data System (ADS)

    Lambrakos, S. G.; Yapijakis, C.; Aiken, D.; Shabaev, A.; Ramsey, S.; Peak, J.

    2016-05-01

    Monitoring of contaminants associated with specific water resources using transmission spectra, with respect to types and relative concentrations, requires tracking statistical profiles of water contaminants in terms of spatial-temporal distributions of electromagnetic absorption spectra ranging from the ultraviolet to infrared. For this purpose, correlation between spectral signatures and types of contaminants within specific water resources must be made, as well as correlation of spectral signatures with results of processes for removal of contaminants, such as ozonation. Correlation between absorption spectra and changes in chemical and physical characteristics of contaminants, within a volume of sampled solution, requires sufficient sensitivity. The present study examines the sensitivity of transmission spectra with respect to general characteristics of water contaminants for spectral analysis of water samples.

  20. Scintillating screens sensitivity and resolution studies for low energy, low intensity beam diagnostics.

    PubMed

    Harasimowicz, Janusz; Cosentino, Luigi; Finocchiaro, Paolo; Pappalardo, Alfio; Welsch, Carsten P

    2010-10-01

    In order to investigate the limits of scintillating screens for beam profile monitoring in the ultra-low energy, ultra-low intensity regime, CsI:Tl, YAG:Ce, and a Tb glass-based scintillating fiber optic plate (SFOP) were tested. The screens response to 200 and 50 keV proton beams with intensities ranging from a few picoampere down to the subfemtoampere region was examined. In the following paper, the sensitivity and resolution studies are presented in detail for CsI:Tl and the SFOP, the two most sensitive screens. In addition, a possible use of scintillators for ultra-low energy antiproton beam monitoring is discussed. PMID:21034082

  1. Study of the sensitivity of gas sensing by use of index-guiding photonic crystal fibers.

    PubMed

    Li, Shu-Guang; Liu, Si-Ying; Song, Zhao-Yuan; Han, Yin; Cheng, Tong-Lei; Zhou, Gui-Yao; Hou, Lan-Tian

    2007-08-01

    We demonstrate an absorption transmission spectrum of CH(4) in a 16.9 cm long index-guiding photonic crystal fiber (PCF) fabricated in our laboratory. One of the main factors to improve the sensitivity is to increase the fraction of power in PCF cladding air holes. We study the fraction of power in PCF cladding air holes as a function of the index-guiding PCF parameters. We found that a PCF with small spacing and a large air-filling ratio has a higher fraction of power in its cladding air holes. At the same time the mode area in this PCF is small and would generate strong nonlinear effects in the fiber. If we use a PCF in which the core is formed by missing seven air holes, it is immediately obvious that the PCF used as a sensor has higher sensitivity and a larger mode area. PMID:17676130

  2. A study of the simulated evolution of the spectral sensitivity of visual agent receptors.

    PubMed

    Liese, A; Polani, D; Uthmann, T

    2001-01-01

    In this article we study a model for the evolution of the spectral sensitivity of visual receptors for agents in a continuous virtual environment. The model uses a genetic algorithm (GA) to evolve the agent sensors along with the control of the agents by requiring the agents to solve certain tasks in the simulation environment. The properties of the evolved sensors are analyzed for different scenarios. In particular, it is shown that the GA is able to find a balance between sensor costs and agent performance in such a way that the spectral sensor sensitivity reflects the emission spectrum of the target objects and that the capability of the sensors to evolve can help the agents significantly in adapting to their task. PMID:11580876

  3. A comprehensive evaluation of various sensitivity analysis methods: A case study with a hydrological model

    SciTech Connect

    Gan, Yanjun; Duan, Qingyun; Gong, Wei; Tong, Charles; Sun, Yunwei; Chu, Wei; Ye, Aizhong; Miao, Chiyuan; Di, Zhenhua

    2014-01-01

    Sensitivity analysis (SA) is a commonly used approach for identifying important parameters that dominate model behaviors. We use a newly developed software package, a Problem Solving environment for Uncertainty Analysis and Design Exploration (PSUADE), to evaluate the effectiveness and efficiency of ten widely used SA methods, including seven qualitative and three quantitative ones. All SA methods are tested using a variety of sampling techniques to screen out the most sensitive (i.e., important) parameters from the insensitive ones. The Sacramento Soil Moisture Accounting (SAC-SMA) model, which has thirteen tunable parameters, is used for illustration. The South Branch Potomac River basin near Springfield, West Virginia in the U.S. is chosen as the study area. The key findings from this study are: (1) For qualitative SA methods, Correlation Analysis (CA), Regression Analysis (RA), and Gaussian Process (GP) screening methods are shown to be not effective in this example. Morris One-At-a-Time (MOAT) screening is the most efficient, needing only 280 samples to identify the most important parameters, but it is the least robust method. Multivariate Adaptive Regression Splines (MARS), Delta Test (DT) and Sum-Of-Trees (SOT) screening methods need about 400–600 samples for the same purpose. Monte Carlo (MC), Orthogonal Array (OA) and Orthogonal Array based Latin Hypercube (OALH) are appropriate sampling techniques for them; (2) For quantitative SA methods, at least 2777 samples are needed for Fourier Amplitude Sensitivity Test (FAST) to identity parameter main effect. McKay method needs about 360 samples to evaluate the main effect, more than 1000 samples to assess the two-way interaction effect. OALH and LPτ (LPTAU) sampling techniques are more appropriate for McKay method. For the Sobol' method, the minimum samples needed are 1050 to compute the first-order and total sensitivity indices correctly. These comparisons show that qualitative SA methods are more efficient

  4. Is Hiding Foot and Mouth Disease Sensitive Behavior for Farmers? A Survey Study in Sri Lanka.

    PubMed

    Gunarathne, Anoma; Kubota, Satoko; Kumarawadu, Pradeep; Karunagoda, Kamal; Kon, Hiroichi

    2016-02-01

    Foot and mouth disease (FMD) has a long history in Sri Lanka and was found to be endemic in various parts of the country and constitutes a constant threat to farmers. In Sri Lanka, currently there is no regular, nationwide vaccination programme devised to control FMD. Therefore, improving farmers' knowledge regarding distinguishing FMD from other diseases and ensuring prompt reporting of any suspicion of FMD as well as restricting movement of animals are critical activities for an effective FMD response effort. Therefore, the main purpose of this study was to clarify the relationship between farmers' knowledge levels and their behaviors to establish a strategy to control FMD. In our study, item count technique was applied to estimate the number of farmers that under-report and sell FMD-infected animals, although to do so is prohibited by law. The following findings were observed: about 63% of farmers have very poor knowledge of routes of FMD transmission; 'under-reporting' was found to be a sensitive behavior and nearly 23% of the farmers were reluctant to report FMD-infected animals; and 'selling FMD-infected animals' is a sensitive behavior among high-level knowledge group while it is a non-sensitive behavior among the low-level knowledge group. If farmers would understand the importance of prompt reporting, they may report any suspected cases of FMD to veterinary officials. However, even if farmers report honestly, they do not want to cull FMD-infected animals. Thus, education programs should be conducted not only on FMD introduction and transmission, but also its impact. Furthermore, consumers may criticize the farmers for culling their infected animals. Hence, not only farmers, but also consumers need to be educated on the economic impact of FMD and the importance of controlling an outbreak. If farmers have a high knowledge of FMD transmission, they consider selling FMD-infected animals as a sensitive behavior. Therefore, severe punishment should be levied for

  5. Screening for symptomatic metal sensitivity: a prospective study of 92 patients undergoing total knee arthroplasty.

    PubMed

    Niki, Yasuo; Matsumoto, Hideo; Otani, Toshiro; Yatabe, Taku; Kondo, Makoto; Yoshimine, Fumihiro; Toyama, Yoshiaki

    2005-03-01

    Metal sensitivity (MS) reactions to implant metals represent a rare but well-documented complication following total joint arthroplasty (TJA). Although 20-25% of post-TJA patients develop MS, only a few highly susceptible patients (< 1%) exhibit symptoms. Whether surgeons should perform screening for MS is currently a matter of debate. The present study investigated the clinical importance of screening for patients predisposed to symptomatic MS, and the specific metals causing symptomatic MS following total knee arthroplasty (TKA). Between 2000 and 2002, a total of 108 primary TKAs were performed on 92 patients. Preoperatively, all patients underwent modified lymphocyte stimulation test (mLST) to Ni, Co, Cr, and Fe. Of the 92 patients, 24 (26%) displayed positive preoperative responses to at least one metal. Five patients displayed implant metal-related eczema and were all mLST-positive preoperatively, suggesting that screening for symptomatic MS is clinically useful. Two of these underwent revision TKA and thereafter, eczema healed and mLST results changed from positive to negative. All mLST-positive patients were divided into three groups: Group I, patients with eczema; Group II, patients with clear history of MS; and Group III, patients neither eczema nor history of MS. When the type of sensitive metals were compared among the three groups, a significant association between presence of Cr-sensitivity and development of eczema (P < 0.05) was identified. No significant association was observed between other metals and development of eczema or history of MS. This indicates that Cr is a potential candidate metal for causing eczema in our TKA series, and Cr-sensitivity may offer a potential predictor for symptomatic MS. The present study indicates that the surgeons should undertake routine preoperative screening for MS, particularly to Cr. PMID:15369690

  6. A comprehensive evaluation of various sensitivity analysis methods: A case study with a hydrological model

    DOE PAGESBeta

    Gan, Yanjun; Duan, Qingyun; Gong, Wei; Tong, Charles; Sun, Yunwei; Chu, Wei; Ye, Aizhong; Miao, Chiyuan; Di, Zhenhua

    2014-01-01

    Sensitivity analysis (SA) is a commonly used approach for identifying important parameters that dominate model behaviors. We use a newly developed software package, a Problem Solving environment for Uncertainty Analysis and Design Exploration (PSUADE), to evaluate the effectiveness and efficiency of ten widely used SA methods, including seven qualitative and three quantitative ones. All SA methods are tested using a variety of sampling techniques to screen out the most sensitive (i.e., important) parameters from the insensitive ones. The Sacramento Soil Moisture Accounting (SAC-SMA) model, which has thirteen tunable parameters, is used for illustration. The South Branch Potomac River basin nearmore » Springfield, West Virginia in the U.S. is chosen as the study area. The key findings from this study are: (1) For qualitative SA methods, Correlation Analysis (CA), Regression Analysis (RA), and Gaussian Process (GP) screening methods are shown to be not effective in this example. Morris One-At-a-Time (MOAT) screening is the most efficient, needing only 280 samples to identify the most important parameters, but it is the least robust method. Multivariate Adaptive Regression Splines (MARS), Delta Test (DT) and Sum-Of-Trees (SOT) screening methods need about 400–600 samples for the same purpose. Monte Carlo (MC), Orthogonal Array (OA) and Orthogonal Array based Latin Hypercube (OALH) are appropriate sampling techniques for them; (2) For quantitative SA methods, at least 2777 samples are needed for Fourier Amplitude Sensitivity Test (FAST) to identity parameter main effect. McKay method needs about 360 samples to evaluate the main effect, more than 1000 samples to assess the two-way interaction effect. OALH and LPτ (LPTAU) sampling techniques are more appropriate for McKay method. For the Sobol' method, the minimum samples needed are 1050 to compute the first-order and total sensitivity indices correctly. These comparisons show that qualitative SA methods are more

  7. Sensitivity of Rooftop PV Projections in the SunShot Vision Study to Market Assumptions

    SciTech Connect

    Drury, E.; Denholm, P.; Margolis, R.

    2013-01-01

    The SunShot Vision Study explored the potential growth of solar markets if solar prices decreased by about 75% from 2010 to 2020. The SolarDS model was used to simulate rooftop PV demand for this study, based on several PV market assumptions--future electricity rates, customer access to financing, and others--in addition to the SunShot PV price projections. This paper finds that modeled PV demand is highly sensitive to several non-price market assumptions, particularly PV financing parameters.

  8. Sensitivity studies of spin cut-off models on fission fragment observables

    NASA Astrophysics Data System (ADS)

    Thulliez, L.; Litaize, O.; Serot, O.

    2016-03-01

    A fission fragment de-excitation code, FIFRELIN, is being developed at CEA Cadarache. It allows probing the characteristics of the prompt emitted particles, neutrons and gammas, during the de-excitation process of fully accelerated fission fragments. The knowledge of the initial states of the fragments is important to accurately reproduce the fission fragment observables. In this paper a sensitivity study of various spin cut-off models, completely defining the initial fission fragment angular momentum distribution has been performed. This study shows that the choice of the model has a significant impact on gamma observables such as spectrum and multiplicity and almost none on the neutron observables.

  9. Structural sensitivity studies of ethylene hydrogenation on platinum and rhodium surfaces

    SciTech Connect

    Quinlan, M.A. |

    1996-01-01

    The catalytic hydrogenation of ethylene and hydrogen on the well characterized surfaces of the noble metals platinum and rhodium has been studied for the purposes of determining the relative activity of these two substrates as well as the degree of structure sensitivity. The Pt(111) and the Rh(755) single crystal surfaces,as well as Pt and Rh foils, were employed as substrates to study the effect of surface step structure on reactivity. In addition, vibrational spectroscopy studies were performed for ethylene adsorption on the stepped Rh(755) surface. The catalytic reaction were obtained using a combined ultrahigh vacuum chamber coupled with an atmospheric pressure reaction chamber that functioned as a batch reactor. Samples could be prepared using standard surface science techniques and characterized for surface composition and geometry using Auger Electron Spectroscopy and Low Energy Electron Diffraction. A comparison of the reactivity of Rh(111) with the results from this study on Rh(755) allows a direct determination of the effect of step structure on ethylene hydrogenation activity. Structure sensitivity is expected to exhibit orders of magnitude differences in rate as surface orientation is varied. In this case, no significant differences were found, confirming the structure insensitivity of this reaction over this metal. The turnover frequency of the Rh(111) surface, 5 {times} 10{sup 1} s{sup {minus}1}, is in relatively good agreement with the turnover frequency of 9 {times} 10{sup 1} s{sup {minus}1} measured for the Rh(755) surface. Rate measurements made on the Pt(111) surface and the Pt foil are in excellent agreement, both measuring 3 {times} 10{sup 2} s{sup minus}1. Likewise, it is concluded that no strong structure sensitivity for the platinum surfaces exists. High Resolution Electron Energy Loss Spectroscopy studies of adsorbed ethylene on the Rh(755) surface compare favorably with the ethylidyne spectra obtained on the Rh(111) and Rh(100) surfaces.

  10. Study of single and combined mass-sensitive observables of cosmic ray induced extensive air showers

    NASA Astrophysics Data System (ADS)

    Rastegarzadeh, G.; Nemati, M.

    2016-03-01

    In this study, combinations of the global arrival time, (Δτ_{global}), pseudorapidity, and lateral density distribution (ρ_{μ}) of muons, which are three mass-sensitive observables of cosmic ray induced extensive air showers, have been used as new parameters to study the primary mass discrimination around the knee energies (100 TeV-10 PeV). This is a simulation-based study and the simulations have been performed for the KASCADE array at Karlsruhe and the Alborz-I array at Tehran to study the effect of the altitude on the quality of the primary mass discrimination. The merit factors of the single and combined three mass-sensitive observables have been calculated to compare the discrimination power of combined and single observables. We have used the CORSIKA 7.4 code to simulate the extensive air showers (EASs) sample sets. Considering all aspects of our study, it is found that the ratio of the global time to the lateral density distribution of the muons gives better results than other ratios; also in the case of single observables, the muon density gives better results compared with the other observables. Also it is shown that below 1 PeV primary energies, the ratio of the muon global time to the muon density (Δτ_{global}/ρ_{μ}) results in a better mass discrimination relative to the muon density only.

  11. Developmental effects of decision-making on sensitivity to reward: An fMRI study

    PubMed Central

    Jarcho, Johanna M; Benson, Brenda E; Plate, Rista C; Guyer, Amanda E; Detloff, Allison M; Pine, Daniel S.; Leibenluft, Ellen; Ernst, Monique

    2012-01-01

    Studies comparing neural correlates of reward processing across development yield inconsistent findings. This challenges theories characterizing adolescents as globally hypo- or hypersensitive to rewards. Developmental differences in reward sensitivity may fluctuate based on reward magnitude, and on whether rewards require decision-making. We examined whether these factors modulate developmental differences in neural response during reward anticipation and/or receipt in 26 adolescents (14.05±2.37yrs) and 26 adults (31.25±8.23yrs). Brain activity was assessed with fMRI during reward anticipation, when subjects made responses with-vs.-without decision-making, to obtain large–vs.–small rewards, and during reward receipt. When reward-receipt required decision-making, neural activity did not differ by age. However, when reward receipt did not require decision-making, neural activity varied by development, reward magnitude, and stage of the reward task. During anticipation, adolescents, but not adults, exhibited greater activity in the insula, extending into putamen, and cingulate gyrus for large-vs.-small incentives. During feedback, adults, but not adolescents, exhibited greater activity in the precuneus for large-vs.-small incentives. These data indicate that age-related differences in reward sensitivity cannot be characterized by global hypo- or hyper-responsivity. Instead, neural responding in striatum, prefrontal cortex and precuneus is influenced by both situational demands and developmental factors. This suggests nuanced maturational effects in adolescent reward sensitivity. PMID:22591860

  12. Luminophore Application Study of Polymer-Ceramic Pressure-Sensitive Paint

    PubMed Central

    Sakaue, Hirotaka; Hayashi, Tatsunori; Ishikawa, Hitoshi

    2013-01-01

    A polymer-ceramic pressure-sensitive paint (PC-PSP) is a fast responding and sprayable PSP which has been applied for capturing global unsteady flows. The luminophore application process is studied to enhance the characterization of the PC-PSP. A dipping deposition method is used to apply a luminophore on a polymer-ceramic coating. The method selects a solvent by its polarity index. The characterization includes the signal level, pressure sensitivity, temperature dependency, and response time. It is found that the luminophore application process affects the steady-state characterizations, such as the signal level, pressure sensitivity, and temperature dependency. A range of change for each characterization, which is based on the minimum quantity, is a factor of 4.7, 9, and 3.8, respectively. A response time on the order of ten microseconds is shown. The application process is not a dominant factor for changing the response time, which is within the uncertainty of the thickness variation. Comparisons of the effects on the luminophore application process and the polymer content are made to discuss the PC-PSP characterization results. PMID:23760088

  13. Application and sensitivity studies of the orographic cloud model MCCP (Mountain Cloud Chemistry Program) PLUVIUS

    SciTech Connect

    Chapman, E.G.; Luecken, D.J.; Whiteman, C.D.

    1987-07-01

    A special MCCP version of the PLUVIUS MOD 5.0 reactive storm model (MCCP PLUVIUS) was applied to conditions representative of Mt. Mitchell, North Carolina. Tests were also conducted to determine the sensitivity of the model to various meteorological and chemical parameters. Results of the modeling investigation indicate that aqueous concentrations and deposition fluxes of pollutants are location dependent. The greatest concentrations occur at the edges of the cloud, where the liquid water content is low, and the greatest deposition flux occurs on the windward side of the mountain. For conditions considered representative of summertime conditions at Mt. Mitchell, predicted ion concentrations in deposited cloud water at a point corresponding to the MCCP field station are within the ranges actually observed. Sensitivity studies indicate that in-cloud oxidation of SO/sub 2/ makes a limited contribution to total sulfate deposition for typical concentrations of SO/sub 2/, O/sub 3/, and H/sub 2/O/sub 2/. However, sulfate deposition predicted by MCCP PLUVIUS is extremely sensitive to the value selected for aerosol sulfate existing in the modeled air mass prior to cloud formation. Hydrogen ion deposition predicted by the model is strongly influenced by input values for gas-phase nitric acid and ammonia. 11 refs., 19 figs., 9 tabs.

  14. Assessment of thermal sensitivity of CT during heating of liver: an ex vivo study

    PubMed Central

    Pandeya, G D; Greuter, M J W; Schmidt, B; Flohr, T; Oudkerk, M

    2012-01-01

    Objectives The purpose of this study was to assess the thermal sensitivity of CT during heating of ex-vivo animal liver. Methods Pig liver was indirectly heated from 20 to 90 °C by passage of hot air through a plastic tube. The temperature in the heated liver was measured using calibrated thermocouples. In addition, image acquisition was performed with a multislice CT scanner before and during heating of the liver sample. The reconstructed CT images were then analysed to assess the change of CT number as a function of temperature. Results During heating, a decrease in CT numbers was observed as a hypodense area on the CT images. In addition, the hypodense area extended outward from the heat source during heating. The analysis showed a linear decrease of CT number as a function of temperature. From this relationship, we derived a thermal sensitivity of CT for pig liver tissue of −0.54±0.03 HU °C−1 with an r2 value of 0.91. Conclusions The assessment of the thermal sensitivity of CT in ex-vivo pig liver tissue showed a linear dependency on temperature ≤90 °C. This result may be beneficial for the application of isotherms or thermal maps in CT images of liver tissue. PMID:22919016

  15. Altered sensitivity to excitotoxic cell death and glutamate receptor expression between two commonly studied mouse strains

    PubMed Central

    Finn, Rozzy; Kovács, Attila D.; Pearce, David A.

    2011-01-01

    Alterations in glutamatergic synapse function have been implicated in the pathogenesis of many different neurological disorders including ischemia, epilepsy, Parkinson’s disease, Alzheimer’s disease, and Huntington’s disease. While studying glutamate receptor function in juvenile Batten disease on the C57BL/6J and 129S6/SvEv mouse backgrounds, we noticed differences unlikely to be due to mutation difference alone. We report here that primary cerebellar granule cell cultures from C57BL/6J mice are more sensitive to NMDA-mediated cell death. Moreover, sensitivity to AMPA-mediated excitotoxicity is more variable and is dependent upon the treatment conditions and age of the cultures. Glutamate receptor surface expression levels examined in vitro by in situ ELISA and in vivo by Western blot in surface cross-linked cerebellar samples indicated that these differences in sensitivity are likely due to strain-dependent differences in cell surface receptor expression levels. We propose that differences in glutamate receptor expression and in excitotoxic vulnerability should be taken into consideration in the context of characterizing disease models on the C57BL/6J and 129S6/SvEv mouse backgrounds. PMID:20544821

  16. Hydrocarbon dissociation on palladium studied with a hydrogen sensitive Pd-metal-oxide-semiconductor structure

    NASA Astrophysics Data System (ADS)

    Dannetun, H.; Lundström, I.; Petersson, L.-G.

    1988-01-01

    The polycrystalline Pd surface of a hydrogen sensitive palladium-silicon dioxide-silicon [Pd-MOS (metal-oxide-semiconductor)] structure has been exposed to small unsaturated hydrocarbons in the temperature range 300-500 K. Apart from the hydrogen response of the Pd-MOS structure also work function (ΔΦ) and electron energy-loss studies were performed. At 500 K the hydrocarbons dissociate completely upon adsorption and produce a surface with atomically adsorbed carbon. The Pd-MOS structure can be used to observe both the dehydrogenation of the hydrocarbon molecules and the process of carbon adsorbing on the palladium surface. The sticking coefficient at this temperature for all hydrocarbons is close to unity. Furthermore, the hydrogen sensitivity of the structure is not drastically reduced by the adsorbed carbon. If the hydrocarbon adsorption is performed at 300 K there is still, at least on the initially clean surface, a large dehydrogenation. The dissociation is, however, not at all complete and there are considerable amounts of hydrocarbon species adsorbed for each gas. The induced work function shifts due to the different hydrocarbons vary from -1.0 to -1.7 eV. The hydrogen sensitivity of the Pd-MOS structure is reduced for growing hydrocarbon coverages and disappears completely for work function shifts of -1.7 eV.

  17. Endogenous Opioid-Masked Latent Pain Sensitization: Studies from Mouse to Human

    PubMed Central

    Dahl, Jørgen B.; Werner, Marianne; Taylor, Bradley K.; Werner, Mads U.

    2015-01-01

    Following the resolution of a severe inflammatory injury in rodents, administration of mu-opioid receptor inverse agonists leads to reinstatement of pain hypersensitivity. The mechanisms underlying this form of latent pain sensitization (LS) likely contribute to the development of chronic pain, but LS has not yet been demonstrated in humans. Using a C57BL/6 mouse model of cutaneous mild heat injury (MHI) we demonstrated a dose-dependent reinstatement of pain sensitization, assessed as primary (P < 0.001) and secondary hyperalgesia (P < 0.001) by naloxone (0.3–10 mg/kg), 168 hrs after the induction of MHI. Forward-translating the dose data to a human MHI model (n = 12) we could show that LS does indeed occur after naloxone 2 mg/kg, 168 hrs after a MHI. Our previous unsuccessful efforts to demonstrate unmasking of LS in humans are thus likely explained by an insufficient naloxone dose (0.021 mg/kg). However, while LS was consistently demonstrated in 21/24 mice, LS was only seen in 4/12 subjects. This difference is likely due to selection bias since the C57BL/6 mouse strain exhibits markedly enhanced pain sensitivity in assays of acute thermal nociception. Future exploratory studies in humans should prioritize inclusion of “high-sensitizers” prone to develop LS and use post-surgical models to elucidate markers of vulnerability to chronic postsurgical pain. Trial Registration EudraCT 2012-005663-27 PMID:26305798

  18. 20th century precipitation changes in the Sahel region: sensitivity studies with ECHAM5-HAM

    NASA Astrophysics Data System (ADS)

    Folini, D.; Baumgartner, D.; Wild, M.

    2012-04-01

    The 20th century has seen an enormous growth in population and industrialization. These changes are accompanied, among others, by a substantial increase in aerosol emission. To learn more about associated consequences for the climate system we have carried out a comparatively large set of transient sensitivity studies with the global atmosphere only climate model ECHAM5-HAM, using aerosol emission data from NIES (National Institute of Environmental Studies, Japan) and prescribed, observation based sea surface temperatures (SSTs) from the Hadley Center. The sensitivity studies cover the period from 1870 to 2005 and comprise ensembles of simulations (up to 13 members per ensemble), which allow to address the role of different aerosol species, greenhouse gases, and prescribed sea surface temperatures. We present a preliminary analysis of these global simulation data for the Sahel region (land within 20W / 35E / 10N / 20N). The annual cycle as well as the overall temporal evolution of precipitation in the Sahel according to CRU (Climate Research Unit, UK) is captured well by the model simulations: two comparatively wet phases in the 1930s and 1950s, a more or less continuous decline thereafter, and a renewed increase in precipitation since the 1980s. This decline / renewed incline since the 1950s is, however, about twice as strong in the CRU data than in the model data. The sensitivity studies reveal SSTs as a prominent factor for the time evolution of precipitation, while the atmosphere only effect of aerosols plays a minor role for the modeled precipitation. The observation based prescribed SSTs may, however, encapsulate and aerosol effect already.

  19. Sensitivity study of an image processing workflow on synchrotron μ-CT images of Berea sandstone

    NASA Astrophysics Data System (ADS)

    Leu, Leon; Berg, Steffen; Ott, Holger; Armstrong, Ryan T.; Enzmann, Frieder; Kersten, Michael

    2014-05-01

    For the present study, the sensitivity of the threshold value for watershed-based segmentation and global threshold segmentation was assessed on μ-CT images of fine grained Berea sandstone. The sensitivities were assessed in terms of porosity, permeability, single-phase flow simulations and capillary pressure curves that were calculated from the segmented data. The μ-CT images of fine grained Berea sandstone with a resolution of 3 μm/pixel was segmented using different threshold values that were systematically varied, which resulted in slightly different structures for the pore space. The results show, that watershed-based segmentation is more robust than global threshold segmentation and that the measured permeability showed a stronger sensitivity to threshold variation than porosity, indicating that it is a more sensitive parameter to image segmentation settings. Calculated permeability and capillary pressure curves matched well with experimental data revealing that the average pores and pore throats of the watershed-based segmented structure were segmented accurately. In contrast, capillary pressure curves indicated that pore sizes near the resolution limit of 3 μm, located in kaolinite rich areas of the rock, were not segmented correctly and thus caused the disagreement between the experimental measured porosity and that measured from the digital rock image. We conclude that capillary pressure curves and permeability values that result from the digital rock data is more indicative of the flow relevant fraction of the pore structure and are therefore better suited as validation criterion than porosity data. Numerical modeling of two-phase flow on segmented data from high resolution μ-CT images enhances our understanding of the dynamics of multiphase-flow of immiscible fluids at the pore-scale. To be confident about simulated data it is therefore important to identify meaningful properties, e.g. permeability, that can be used as benchmark parameters for

  20. A magnetotelluric study of the sensitivity of an area to seismoelectric signals

    USGS Publications Warehouse

    Balasis, G.; Bedrosian, P.A.; Eftaxias, K.

    2005-01-01

    During recent years, efforts at better understanding the physical properties of precursory ultra-low frequency pre-seismic electric signals (SES) have been intensified. Experiments show that SES cannot be observed at all points of the Earth's surface but only at certain so-called sensitive sites. Moreover, a sensitive site is capable of collecting SES from only a restricted number of seismic areas (selectivity effect). Tberefore the installation of a permanent station appropriate for SES collection should necessarily be preceded by a pilot study over a broad area and for a long duration. In short, a number of temporary stations are installed and, after the occurrence of several significant earthquakes (EQs) from a given seismic area, the most appropriate (if any) of these temporary stations, in the sense that they happen to collect SES, can be selected as permanent. Such a long experiment constitutes a serious disadvantage in identifying a site as SES sensitive. However, the SES sensitivity of a site should be related to the geoelectric structure of the area that hosts the site as well as the regional geoelectric structure between the station and the seismic focal area. Thus, knowledge of the local and regional geoelectric structure can dramatically reduce the time involved in identifying SES sites. hi this paper the magnetotelluric method is used to investigate the conductivity structure of an area where a permanent SES station is in operation. Although general conclusions cannot be drawn, the area surrounding an SES site near Ioannina, Greece is characterized by: (1) major faults in the vicinity; (2) highly resistive structure flanked by abrupt conductivity contrasts associated with large-scale geologic contacts, and (3) local inhomogeneities in conductivity structure. The above results are consistent with the fact that electric field amplitudes from remotely-generated signals should be appreciably stronger at such sites when compared to neighboring sites

  1. Laboratory Measurements and Model Sensitivity Studies of Dust Deposition Ice Nucleation

    SciTech Connect

    Kulkarni, Gourihar R.; Fan, Jiwen; Comstock, Jennifer M.; Liu, Xiaohong; Ovchinnikov, Mikhail

    2012-08-16

    We investigated the ice nucleating properties of mineral dust particles to understand the sensitivity of simulated cloud properties to two different representations of contact angle in the Classical Nucleation Theory (CNT). These contact angle representations are based on two sets of laboratory deposition ice nucleation measurements: Arizona Test Dust (ATD) particles of 100, 300 and 500 nm sizes were tested at three different temperatures (-25, -30 and -35 C), and 400 nm ATD and kaolinite dust species were tested at two different temperatures (-30 and -35 C). These measurements were used to derive the onset relative humidity with respect to ice (RH{sub ice}) required to activate 1% of dust particles as ice nuclei, from which the onset single contact angles were then calculated based on CNT. For the probability density function (PDF) representation, parameters of the log-normal contact angle distribution were determined by fitting CNT-predicted activated fraction to the measurements at different RH{sub ice}. Results show that onset single contact angles vary from {approx}18 to 24 degrees, while the PDF parameters are sensitive to the measurement conditions (i.e. temperature and dust size). Cloud modeling simulations were performed to understand the sensitivity of cloud properties (i.e. ice number concentration, ice water content, and cloud initiation times) to the representation of contact angle and PDF distribution parameters. The model simulations show that cloud properties are sensitive to onset single contact angles and PDF distribution parameters. The comparison of our experimental results with other studies shows that under similar measurement conditions the onset single contact angles are consistent within {+-}2.0 degrees, while our derived PDF parameters have larger discrepancies.

  2. A piecewise modeling approach for climate sensitivity studies: Tests with a shallow-water model

    NASA Astrophysics Data System (ADS)

    Shao, Aimei; Qiu, Chongjian; Niu, Guo-Yue

    2015-10-01

    In model-based climate sensitivity studies, model errors may grow during continuous long-term integrations in both the "reference" and "perturbed" states and hence the climate sensitivity (defined as the difference between the two states). To reduce the errors, we propose a piecewise modeling approach that splits the continuous long-term simulation into subintervals of sequential short-term simulations, and updates the modeled states through re-initialization at the end of each subinterval. In the re-initialization processes, this approach updates the reference state with analysis data and updates the perturbed states with the sum of analysis data and the difference between the perturbed and the reference states, thereby improving the credibility of the modeled climate sensitivity. We conducted a series of experiments with a shallow-water model to evaluate the advantages of the piecewise approach over the conventional continuous modeling approach. We then investigated the impacts of analysis data error and subinterval length used in the piecewise approach on the simulations of the reference and perturbed states as well as the resulting climate sensitivity. The experiments show that the piecewise approach reduces the errors produced by the conventional continuous modeling approach, more effectively when the analysis data error becomes smaller and the subinterval length is shorter. In addition, we employed a nudging assimilation technique to solve possible spin-up problems caused by re-initializations by using analysis data that contain inconsistent errors between mass and velocity. The nudging technique can effectively diminish the spin-up problem, resulting in a higher modeling skill.

  3. Abatacept improves whole-body insulin sensitivity in rheumatoid arthritis: an observational study.

    PubMed

    Ursini, Francesco; Russo, Emilio; Letizia Hribal, Marta; Mauro, Daniele; Savarino, Francesca; Bruno, Caterina; Tripolino, Cesare; Rubino, Mariangela; Naty, Saverio; Grembiale, Rosa Daniela

    2015-05-01

    Rheumatoid arthritis (RA) is characterized by increased insulin resistance, a well-known risk factor for diabetes and cardiovascular diseases. The aim of the present study was to evaluate the effect of abatacept on insulin sensitivity in RA patients with moderate to severe disease despite treatment with methotrexate. Fifteen RA patients were recruited for the present study. Patients were evaluated at time 0 and after 6 months of the treatment with i.v. abatacept at the dosage recommended for weight range. Evaluation included oral glucose tolerance test (OGTT) at both time points. Insulin sensitivity was estimated with insulin sensitivity index (ISI) by Matsuda, a measure of whole-body insulin sensitivity. ISI significantly increased after the treatment with abatacept from 3.7 ± 2.6 to 5.0 ± 3.2 (P = 0.003) with a mean difference of 1.23. Analysis of glucose and insulin values during OGTT revealed a reduction of both glucose (303.9 ± 73.4 mg/dL min versus 269.2 ± 69.5 mg/dL min, P = 0.009) and insulin (208.4 ± 119.7 mg/dL min versus 158.0 ± 95.3 mg/dL min, P = 0.01) area under the curves (AUCs). Accordingly also glycated hemoglobin significantly improved (5.5 ± 0.4% versus 5.3 ± 0.3%, P = 0.04). No significant differences were found for measures of β-cell function insulinogenic index (1.11 ± 1.19 versus 1.32 ± 0.82, P = 0.77) and oral disposition index (2.0 ± 5.4 versus 6.0 ± 6.0, P = 0.25). Treatment with abatacept seems to be able to improve whole-body insulin sensitivity in RA patients without affecting β-cell function. PMID:26020396

  4. Parametric Sensitivity Study of Operating and Design Variables in Wellbore Heat Exchangers

    SciTech Connect

    Nalla, G.; Shook, G.M.; Mines, G.L.; Bloomfield, K.K.

    2004-05-01

    This report documents the results of an extensive sensitivity study conducted by the Idaho National Engineering and Environmental Laboratory. This study investigated the effects of various operating and design parameters on wellbore heat exchanger performance to determine conditions for optimal thermal energy extraction and evaluate the potential for using a wellbore heat exchanger model for power generation. Variables studied included operational parameters such as circulation rates, wellbore geometries and working fluid properties, and regional properties including basal heat flux and formation rock type. Energy extraction is strongly affected by fluid residence time, heat transfer contact area, and formation thermal properties. Water appears to be the most appropriate working fluid. Aside from minimal tubing insulation, tubing properties are second order effects. On the basis of the sensitivity study, a best case model was simulated and the results compared against existing low-temperature power generation plants. Even assuming ideal work conversion to electric power, a wellbore heat exchange model cannot generate 200 kW (682.4e+3 BTU/h) at the onset of pseudosteady state. Using realistic conversion efficiency, the method is unlikely to generate 50 kW (170.6e+3 BTU/h).

  5. Study of the sensitivity of neonates to digoxin: contribution of erythrocyte /sup 86/Rb uptake test

    SciTech Connect

    Zannad, F.; Marchal, F.; Royer, R.J.; Vert, P.; Robert, J.

    1981-01-01

    In general, there is little agreement how digoxin should be used in newborn, and the results of studies in this field seem contradictory. This study attempts a quantitative assessment of the number and the sensitivity of cellular receptors for digoxin in the organism, by the in vitro measurement of erythrocyte /sup 86/Rb neonates compared with adults and old people. Red blood cells are first incubated with differing concentrations of digoxin, and then incubated with /sup 86/Rb. The initial level of /sup 86/Rb uptake (Rbi) is that observed in the absence of digoxin. The 50% index of captation (IC50) is the digoxin concentration in nanograms per ml at which /sup 86/Rb uptake is half Rbi. Three grups of patients were studied: Group I: 12 neonates, less that 5 days old; Group II: 11 adults (26 to 57 years old); Group III: 9 elderly people (71 to 82 years old). Rbi was significantly lower in neonates (Mean +/- SD: 25.8% +/- 3.5, P less than 0.001) and in the elderly (29.9% +/- 3.1) than in adults (36.8% +/- 4.6). IC50 was significantly lower in the elderly (12.1 mg/ml +/- 2.4) than in the adult patients (20.5 ng/ml +/- 5.5, P less than 0.001). In the newborns, values of IC50 were widely scattered (16.2 ng/ml +/- 7.2). The authors suggest that since Rbi reflects Na+, K+-ATPase activity, this activity is diminished in newborn and old people, and indicates that they have fewer cellular recaptors for digoxin than adults. In the elderly, the low IC50 would imply increased sensitivity to digoxin. In neonates, the wide range of values for IC50 suggests considerable individual variation in sensitivity to digoxin. The results aer consistent with the recently recomnended lower dosages of digoxin i neonates.

  6. Study on The Response Improvement of A Linear Actuator Using Temperature-Sensitive Magnetic Material

    NASA Astrophysics Data System (ADS)

    Hirata, Katsuhiro; Kanzaki, Yasunori; Ota, Tomohiro; Yamaguchi, Tadashi; Kawase, Yoshihiro

    We have been studying a linear actuator for the thermostatic switch using temperature-sensitive magnetic material (TSMM). In this paper, the effect of the geometry of TSMM on response time is investigated by computing the dynamic characteristics of the actuator employing the 3-D finite element method coupled with the equations of magnetic field, heat transfer and motion. As a result, it is found that the response of the actuator is greatly improved. The validity of the computation is clarified though the comparison with the measurement of a prototype.

  7. Turbulence Model Sensitivity and Scour Gap Effect of Unsteady Flow around Pipe: A CFD Study

    PubMed Central

    Ali, Abbod; Sharma, R. K.; Ganesan, P.

    2014-01-01

    A numerical investigation of incompressible and transient flow around circular pipe has been carried out at different five gap phases. Flow equations such as Navier-Stokes and continuity equations have been solved using finite volume method. Unsteady horizontal velocity and kinetic energy square root profiles are plotted using different turbulence models and their sensitivity is checked against published experimental results. Flow parameters such as horizontal velocity under pipe, pressure coefficient, wall shear stress, drag coefficient, and lift coefficient are studied and presented graphically to investigate the flow behavior around an immovable pipe and scoured bed. PMID:25136666

  8. Microcalorimetry is a sensitive method for studying the effect of nucleotide mutation on promoter activity.

    PubMed

    Yang, Yang; Zhu, Juncheng; Liu, Yi; Shen, Ping; Qu, Songsheng

    2005-03-31

    Microcalorimetric method was successfully used to study the effect of nucleotide mutations on promoter activity and identify the important nucleotide necessary for the promoter function in Escherichia coli. The thermokinetic parameters, such as k, I and IC(50), were calculated from the metabolic power-time curves obtained by microcalorimetric measurement using the TAM air Isothermal Microcalorimeter (manufactured by Thermometric AB company of Sweden). Analysis of these data revealed that different nucleotide mutations in -10 box sequence of RM07 fragment had different effect on the promoter activity. Our research also suggest that the microcalorimetric method is a very sensitive and easily performed method for investigation of promoter mutation. PMID:15733578

  9. Sensitivity Study of the Wall Interference Correction System (WICS) for Rectangular Tunnels

    NASA Technical Reports Server (NTRS)

    Walker, Eric L.; Everhart, Joel L.; Iyer, Venkit

    2001-01-01

    An off-line version of the Wall Interference Correction System (WICS) has been implemented for the NASA Langley National Transonic Facility. The correction capability is currently restricted to corrections for solid wall interference in the model pitch plane for Mach numbers less than 0.45 due to a limitation in tunnel calibration data. A study to assess output sensitivity to measurement uncertainty was conducted to determine standard operational procedures and guidelines to ensure data quality during the testing process. Changes to the current facility setup and design recommendations for installing the WICS code into a new facility are reported.

  10. Experimental Study of Highly Sensitive Sensor Using a Surface Acoustic Wave Resonator for Wireless Strain Detection

    NASA Astrophysics Data System (ADS)

    Bao; Zhongqing; Hara, Motoaki; Mitsui, Misato; Sano, Koji; Nagasawa, Sumito; Kuwano, Hiroki

    2012-07-01

    We developed a highly sensitive strain sensor employing a surface acoustic wave (SAW) resonator for a wireless sensing system. The aim of this study is to monitor the distribution of the strain in the earth crust or giant infrastructures, such as bridges, skyscrapers and power plants, for disaster prevention. A SAW strain sensor was fabricated using LiNbO3 and a quartz substrate, and applied in a tensile test by attaching the steel specimen based on Japanese Industrial Standards (JIS Z2441-1). The results confirmed that the developed sensor could detect a strain of 10-6 order with linearity.

  11. Sensitivity studies for incorporating the direct effect of sulfate aerosols into climate models

    NASA Astrophysics Data System (ADS)

    Miller, Mary Rawlings Lamberton

    2000-09-01

    Aerosols have been identified as a major element of the climate system known to scatter and absorb solar and infrared radiation, but the development of procedures for representing them is still rudimentary. This study addresses the need to improve the treatment of sulfate aerosols in climate models by investigating how sensitive radiative particles are to varying specific sulfate aerosol properties. The degree to which sulfate particles absorb or scatter radiation, termed the direct effect, varies with the size distribution of particles, the aerosol mass density, the aerosol refractive indices, the relative humidity and the concentration of the aerosol. This study develops 504 case studies of altering sulfate aerosol chemistry, size distributions, refractive indices and densities at various ambient relative humidity conditions. Ammonium sulfate and sulfuric acid aerosols are studied with seven distinct size distributions at a given mode radius with three corresponding standard deviations implemented from field measurements. These test cases are evaluated for increasing relative humidity. As the relative humidity increases, the complex index of refraction and the mode radius for each distribution correspondingly change. Mie theory is employed to obtain the radiative properties for each case study. The case studies are then incorporated into a box model, the National Center of Atmospheric Research's (NCAR) column radiation model (CRM), and NCAR's community climate model version 3 (CCM3) to determine how sensitive the radiative properties and potential climatic effects are to altering sulfate properties. This study found the spatial variability of the sulfate aerosol leads to regional areas of intense aerosol forcing (W/m2). These areas are particularly sensitive to altering sulfate properties. Changes in the sulfate lognormal distribution standard deviation can lead to substantial regional differences in the annual aerosol forcing greater than 2 W/m 2. Changes in the

  12. Mask roughness induced LER control and mitigation: aberrations sensitivity study and alternate illumination scheme

    NASA Astrophysics Data System (ADS)

    McClinton, Brittany M.; Naulleau, Patrick P.

    2011-04-01

    Here we conduct a mask-roughness-induced line-edge-roughness (LER) aberrations sensitivity study both as a random distribution amongst the first 16 Fringe Zernikes (for overall aberration levels of 0.25, 0.50, and 0.75nm rms) as well as an individual aberrations sensitivity matrix over the first 37 Fringe Zernikes. Full 2D aerial image modeling for an imaging system with NA = 0.32 was done for both the 22-nm and 16-nm half-pitch nodes on a rough mask with a replicated surface roughness (RSR) of 100 pm and a correlation length of 32 nm at the nominal extreme-ultraviolet lithography (EUVL) wavelength of 13.5nm. As the ideal RSR value for commercialization of EUVL is 50 pm and under, and furthermore as has been shown elsewhere, a correlation length of 32 nm of roughness on the mask sits on the peak LER value for an NA = 0.32 imaging optic, these mask roughness values and consequently the aberration sensitivity study presented here, represent a worst-case scenario. The illumination conditions were chosen based on the possible candidates for the 22-nm and 16-nm half-pitch nodes, respectively. In the 22-nm case, a disk illumination setting of σ = 0.50 was used, and for the 16-nm case, crosspole illumination with σ = 0.10 at an optimum offset of dx = 0 and dy = .67 in sigma space. In examining how to mitigate mask roughness induced LER, we considered an alternate illumination scheme whereby a traditional dipole's angular spectrum is extended in the direction parallel to the line-and-space mask absorber pattern to represent a "strip". While this illumination surprisingly provides minimal improvement to the LER as compared to several alternate illumination schemes, the overall imaging quality in terms of image-log-slope (ILS) and contrast is improved.

  13. Mask roughness induced LER control and mitigation: aberrations sensitivity study and alternate illumination scheme

    SciTech Connect

    McClinton, Brittany M.; Naulleau, Patrick P.

    2011-03-11

    Here we conduct a mask-roughness-induced line-edge-roughness (LER) aberrations sensitivity study both as a random distribution amongst the first 16 Fringe Zernikes (for overall aberration levels of 0.25, 0.50, and 0.75nm rms) as well as an individual aberrations sensitivity matrix over the first 37 Fringe Zernikes. Full 2D aerial image modeling for an imaging system with NA = 0.32 was done for both the 22-nm and 16-nm half-pitch nodes on a rough mask with a replicated surface roughness (RSR) of 100 pm and a correlation length of 32 nm at the nominal extreme-ultraviolet lithography (EUVL) wavelength of 13.5nm. As the ideal RSR value for commercialization of EUVL is 50 pm and under, and furthermore as has been shown elsewhere, a correlation length of 32 nm of roughness on the mask sits on the peak LER value for an NA = 0.32 imaging optic, these mask roughness values and consequently the aberration sensitivity study presented here, represent a worst-case scenario. The illumination conditions were chosen based on the possible candidates for the 22-nm and 16-nm half-pitch nodes, respectively. In the 22-nm case, a disk illumination setting of {sigma} = 0.50 was used, and for the 16-nm case, crosspole illumination with {sigma} = 0.10 at an optimum offset of dx = 0 and dy = .67 in sigma space. In examining how to mitigate mask roughness induced LER, we considered an alternate illumination scheme whereby a traditional dipole's angular spectrum is extended in the direction parallel to the line-and-space mask absorber pattern to represent a 'strip'. While this illumination surprisingly provides minimal improvement to the LER as compared to several alternate illumination schemes, the overall imaging quality in terms of image-log-slope (ILS) and contrast is improved.

  14. Sensitivity Studies for Space-based Measurement of Atmospheric Total Column Carbon Dioxide Using Reflected Sunlight

    NASA Technical Reports Server (NTRS)

    Mao, Jianping; Kawa, S. Randolph

    2003-01-01

    A series of sensitivity studies is carried out to explore the feasibility of space-based global carbon dioxide (CO2) measurements for global and regional carbon cycle studies. The detection method uses absorption of reflected sunlight in the CO2 vibration-rotation band at 1.58 microns. The sensitivities of the detected radiances are calculated using the line-by-line model (LBLRTM), implemented with the DISORT (Discrete Ordinates Radiative Transfer) model to include atmospheric scattering in this band. The results indicate that (a) the small (approx.1%) changes in CO2 near the Earth's surface are detectable in this CO2 band provided adequate sensor signal-to-noise ratio and spectral resolution are achievable; (b) the radiance signal or sensitivity to CO2 change near the surface is not significantly diminished even in the presence of aerosols and/or thin cirrus clouds in the atmosphere; (c) the modification of sunlight path length by scattering of aerosols and cirrus clouds could lead to large systematic errors in the retrieval; therefore, ancillary aerosol/cirrus cloud data are important to reduce retrieval errors; (d) CO2 retrieval requires good knowledge of the atmospheric temperature profile, e.g. approximately 1K RMS error in layer temperature; (e) the atmospheric path length, over which the CO2 absorption occurs, must be known in order to correctly interpret horizontal gradients of CO2 from the total column CO2 measurement; thus an additional sensor for surface pressure measurement needs to be attached for a complete measurement package.

  15. Sensitivity Studies for Space-based Measurements of Atmospheric Total Column Carbon Dioxide Using Reflected Sunlight

    NASA Technical Reports Server (NTRS)

    Mao, Jianping; Kawa, S. Randolph

    2003-01-01

    A series of sensitivity studies is carried out to explore the feasibility of space-based global carbon dioxide (CO2) measurements for global and regional carbon cycle studies. The detection method uses absorption of reflected sunlight in the CO2 vibration-rotation band at 1.58 micron. The sensitivities of the detected radiances are calculated using the line-by-line model (LBLRTM), implemented with the DISORT (Discrete Ordinates Radiative Transfer) model to include atmospheric scattering in this band. The results indicate that (a) the small (approx.1%) changes in CO2 near the Earth's surface are detectable in this CO2 band provided adequate sensor signal-to-noise ratio and spectral resolution are achievable; (b) the effects of other interfering constituents, such as water vapor, aerosols and cirrus clouds, on the radiance are significant but the overall effects of the modification of light path length on total back-to-space radiance sensitivity to CO2 change are minor for general cases, which means that generally the total column CO2 can be derived in high precision from the ratio of the on-line center to off-line radiances; (c) together with CO2 gas absorption aerosol/cirrus cloud layer has differential scattering which may result in the modification of on-line to off-line radiance ratio which could lead a large bias in the total column CO2 retrieval. Approaches to correct such bias need further investigation. (d) CO2 retrieval requires good knowledge of the atmospheric temperature profile, e.g. approximately 1K RMS error in layer temperature, which is achievable from new atmospheric sounders in the near future; (e) the atmospheric path length, over which the CO2 absorption occurs, should be known in order to correctly interpret horizontal gradients of CO2 from the total column CO2 measurement; thus an additional sensor for surface pressure measurement needs to be attached for a complete measurement package.

  16. Shyness-Sensitivity and Social, School, and Psychological Adjustment in Urban Chinese Children: A Four-Wave Longitudinal Study.

    PubMed

    Yang, Fan; Chen, Xinyin; Wang, Li

    2015-01-01

    This study examined reciprocal contributions between shyness-sensitivity and social, school, and psychological adjustment in urban Chinese children. Longitudinal data were collected once a year from Grade 3 to Grade 6 (ages 9-12 years) for 1,171 children from multiple sources. Shyness-sensitivity positively contributed to social, school, and psychological difficulties over time, with the most consistent effects on peer preference and loneliness. Social and school adjustment negatively contributed to the development of shyness-sensitivity. The initial levels of shyness-sensitivity and social and school adjustment moderated the growth of each other, mainly as a resource-potentiating factor. The results indicate the significance of shyness-sensitivity for adjustment and the role of adjustment in the development of shyness-sensitivity in today's urban Chinese society. PMID:26331958

  17. Numerical study of premixed HCCI engine combustion and its sensitivity to computational mesh and model uncertainties

    NASA Astrophysics Data System (ADS)

    Kong, Song-Charng; Reitz, Rolf D.

    2003-06-01

    This study used a numerical model to investigate the combustion process in a premixed iso-octane homogeneous charge compression ignition (HCCI) engine. The engine was a supercharged Cummins C engine operated under HCCI conditions. The CHEMKIN code was implemented into an updated KIVA-3V code so that the combustion could be modelled using detailed chemistry in the context of engine CFD simulations. The model was able to accurately simulate the ignition timing and combustion phasing for various engine conditions. The unburned hydrocarbon emissions were also well predicted while the carbon monoxide emissions were under predicted. Model results showed that the majority of unburned hydrocarbon is located in the piston-ring crevice region and the carbon monoxide resides in the vicinity of the cylinder walls. A sensitivity study of the computational grid resolution indicated that the combustion predictions were relatively insensitive to the grid density. However, the piston-ring crevice region needed to be simulated with high resolution to obtain accurate emissions predictions. The model results also indicated that HCCI combustion and emissions are very sensitive to the initial mixture temperature. The computations also show that the carbon monoxide emissions prediction can be significantly improved by modifying a key oxidation reaction rate constant.

  18. Phase Sensitive X-Ray Diffraction Imaging Study of Protein Crystals

    NASA Technical Reports Server (NTRS)

    Hu, Z. W.

    2003-01-01

    The study of defects and growth of protein crystals is of importance in providing a fundamental understanding of this important category of systems and the rationale for crystallization of better ordered crystals for structural determination and drug design. Yet, as a result of the extremely weak scattering power of x-rays in protein and other biological macromolecular crystals, the extinction lengths for those crystals are extremely large and, roughly speaking, of the order of millimeters on average compared to the scale of micrometers for most small molecular crystals. This has significant implication for x-ray diffraction and imaging study of protein crystals, and presents an interesting challenge to currently available x-ray analytical techniques. We proposed that coherence-based phase sensitive x-ray diffraction imaging could provide a way to augment defect contrast in x-ray diffraction images of weakly diffracting biological macromolecular crystals. I shall examine the principles and ideas behind this approach and compare it to other available x-ray topography and diffraction methods. I shall then present some recent experimental results in two model protein systems-cubic apofemtin and tetragonal lysozyme crystals to demonstrate the capability of the coherence-based imaging method in mapping point defects, dislocations, and the degree of perfection of biological macromolecular crystals with extreme sensitivity. While further work is under way, it is intended to show that the observed new features have yielded important information on protein crystal perfection and nucleation and growth mechanism otherwise unobtainable.

  19. Development of a sensitive mid-infrared spectrometer for the study of cooled molecular ions

    NASA Astrophysics Data System (ADS)

    Porambo, Michael W.

    The study of molecular ions is relevant to many areas of scientific interest. Mid-infrared laser spectroscopy functions as a useful tool for understanding the role of molecular ions in these areas. To this end, a broadly tunable mid-infrared difference frequency generation noise-immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS) system has been developed and characterized through rovibrational spectroscopy of methane. In addition, an attempt was made to use this spectrometer to probe molecular ions focused into an ion beam. Challenges inherent to laboratory molecular ion spectroscopy, such as quantum dilution at high internal temperatures and low ion number density, have been addressed through the development of an instrument that produces rotationally cooled molecular ions coupled to the highly sensitive spectroscopic technique NICE-OHMS. The instrument was first explored as an extension of an ion beam spectrometer by the integration of a continuous supersonic expansion discharge source for the production of the cooled molecular ions. Issues with the implementation led to the re- design of the instrument for spectroscopically probing a supersonic expansion discharge directly with NICE-OHMS. After implementing discharge modulation of the supersonic expansion source, spectra of rotationally cooled H(3/+) and HN(+/2) were acquired. This instrumental development and preliminary spectroscopy has paved the way for a new method for the sensitive spectroscopic study of cooled molecular ions that will aid further insight into these chemical species in many fields.

  20. Sensitivity studies for the main r process: β-decay rates

    SciTech Connect

    Mumpower, M.; Cass, J.; Passucci, G.; Aprahamian, A.; Surman, R.

    2014-04-15

    The pattern of isotopic abundances produced in rapid neutron capture, or r-process, nucleosynthesis is sensitive to the nuclear physics properties of thousands of unstable neutron-rich nuclear species that participate in the process. It has long been recognized that the some of the most influential pieces of nuclear data for r-process simulations are β-decay lifetimes. In light of experimental advances that have pushed measurement capabilities closer to the classic r-process path, we revisit the role of individual β-decay rates in the r process. We perform β-decay rate sensitivity studies for a main (A > 120) r process in a range of potential astrophysical scenarios. We study the influence of individual rates during (n, γ)-(γ, n) equilibrium and during the post-equilibrium phase where material moves back toward stability. We confirm the widely accepted view that the most important lifetimes are those of nuclei along the r-process path for each astrophysical scenario considered. However, we find in addition that individual β-decay rates continue to shape the final abundance pattern through the post-equilibrium phase, for as long as neutron capture competes with β decay. Many of the lifetimes important for this phase of the r process are within current or near future experimental reach.

  1. Mesoscale Assimilation of TMI Rainfall Data with 4DVAR: Sensitivity Studies

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo; Pu, Zhaoxia

    2003-01-01

    Sensitivity studies are performed on the assimilation of TRMM (Tropical Rainfall Measurement Mission) Microwave Imager (TMI) derived rainfall data into a mesoscale model using a four-dimensional variational data assimilation (4DVAR) technique. A series of numerical experiments is conducted to evaluate the impact of TMI rainfall data on the numerical simulation of Hurricane Bonnie (1998). The results indicate that rainfall data assimilation is sensitive to the error characteristics of the data and the inclusion of physics in the adjoint and forward models. In addition, assimilating the rainfall data alone is helpful for producing a more realistic eye and rain bands in the hurricane but does not ensure improvements in hurricane intensity forecasts. Further study indicated that it is necessary to incorporate TMI rainfall data together with other types of data such as wind data into the model, in which case the inclusion of the rainfall data further improves the intensity forecast of the hurricane. This implies that proper constraints may be needed for rainfall assimilation.

  2. Parameter sensitivity study of Arctic aerosol vertical distribution in CAM5

    NASA Astrophysics Data System (ADS)

    Jiao, C.; Flanner, M.

    2015-12-01

    Arctic surface temperature response to light-absorbing aerosols (black carbon, brown carbon and dust) depends strongly on their vertical distributions. Improving model simulations of three dimensional aerosol fields in the remote Arctic region will therefore lead to improved projections of the climate change caused by aerosol emissions. In this study, we investigate how different physical parameterizations in the Community Atmosphere Model version 5 (CAM5) influence the simulated vertical distribution of Arctic aerosols. We design experiments to test the sensitivity of the simulated aerosol fields to perturbations of selected aerosol process-related parameters in the Modal Aerosol Module with seven lognormal modes (MAM7), such as those govern aerosol aging, in-cloud and below-cloud scavenging, aerosol hygroscopicity and so on. The simulations are compared with observed aerosol vertical distributions and total optical depth to assess model performance and quantify uncertainties associated with these model parameterizations. Observations applied here include Arctic aircraft measurements of black carbon and sulfate vertical profiles, along with Aerosol Robotic Network (AERONET) optical depth measurements. We also assess the utility of using High Spectral Resolution Lidar (HSRL) measurements from the ARM Barrow site to infer vertical profiles of aerosol extinction. The sensitivity study explored here will provide guidance for optimizing global aerosol simulations.

  3. Model-based POD study of manual ultrasound inspection and sensitivity analysis using metamodel

    NASA Astrophysics Data System (ADS)

    Ribay, Guillemette; Artusi, Xavier; Jenson, Frédéric; Reece, Christopher; Lhuillier, Pierre-Emile

    2016-02-01

    The reliability of NDE can be quantified by using the Probability of Detection (POD) approach. Former studies have shown the potential of the model-assisted POD (MAPOD) approach to replace expensive experimental determination of POD curves. In this paper, we make use of CIVA software to determine POD curves for a manual ultrasonic inspection of a heavy component, for which a whole experimental POD campaign was not available. The influential parameters were determined by expert analysis. The semi-analytical models used in CIVA for wave propagation and beam-defect interaction have been validated in the range of variation of the influential parameters by comparison with finite element modelling (Athena). The POD curves are computed for « hit/miss » and « â versus a » analysis. The verification of Berens hypothesis is evaluated by statistical tools. A sensitivity study is performed to measure the relative influence of parameters on the defect response amplitude variance, using the Sobol sensitivity index. A meta-model is also built to reduce computing cost and enhance the precision of estimated index.

  4. Shyness-Sensitivity and Social, School, and Psychological Adjustment in Urban Chinese Children: A Four-Wave Longitudinal Study

    ERIC Educational Resources Information Center

    Yang, Fan; Chen, Xinyin; Wang, Li

    2015-01-01

    This study examined reciprocal contributions between shyness-sensitivity and social, school, and psychological adjustment in urban Chinese children. Longitudinal data were collected once a year from Grade 3 to Grade 6 (ages 9-12 years) for 1,171 children from multiple sources. Shyness-sensitivity positively contributed to social, school, and…

  5. Radar sensitivity and antenna scan pattern study for a satellite-based Radar Wind Sounder (RAWS)

    NASA Technical Reports Server (NTRS)

    Stuart, Michael A.

    1992-01-01

    Modeling global atmospheric circulations and forecasting the weather would improve greatly if worldwide information on winds aloft were available. Recognition of this led to the inclusion of the LAser Wind Sounder (LAWS) system to measure Doppler shifts from aerosols in the planned for Earth Observation System (EOS). However, gaps will exist in LAWS coverage where heavy clouds are present. The RAdar Wind Sensor (RAWS) is an instrument that could fill these gaps by measuring Doppler shifts from clouds and rain. Previous studies conducted at the University of Kansas show RAWS as a feasible instrument. This thesis pertains to the signal-to-noise ratio (SNR) sensitivity, transmit waveform, and limitations to the antenna scan pattern of the RAWS system. A dop-size distribution model is selected and applied to the radar range equation for the sensitivity analysis. Six frequencies are used in computing the SNR for several cloud types to determine the optimal transmit frequency. the results show the use of two frequencies, one higher (94 GHz) to obtain sensitivity for thinner cloud, and a lower frequency (24 GHz) to obtain sensitivity for thinner cloud, and a lower frequency (24 GHz) for better penetration in rain, provide ample SNR. The waveform design supports covariance estimation processing. This estimator eliminates the Doppler ambiguities compounded by the selection of such high transmit frequencies, while providing an estimate of the mean frequency. the unambiguous range and velocity computation shows them to be within acceptable limits. The design goal for the RAWS system is to limit the wind-speed error to less than 1 ms(exp -1). Due to linear dependence between vectors for a three-vector scan pattern, a reasonable wind-speed error is unattainable. Only the two-vector scan pattern falls within the wind-error limits for azimuth angles between 16 deg to 70 deg. However, this scan only allows two components of the wind to be determined. As a result, a technique is

  6. Is Hiding Foot and Mouth Disease Sensitive Behavior for Farmers? A Survey Study in Sri Lanka

    PubMed Central

    Gunarathne, Anoma; Kubota, Satoko; Kumarawadu, Pradeep; Karunagoda, Kamal; Kon, Hiroichi

    2016-01-01

    Foot and mouth disease (FMD) has a long history in Sri Lanka and was found to be endemic in various parts of the country and constitutes a constant threat to farmers. In Sri Lanka, currently there is no regular, nationwide vaccination programme devised to control FMD. Therefore, improving farmers’ knowledge regarding distinguishing FMD from other diseases and ensuring prompt reporting of any suspicion of FMD as well as restricting movement of animals are critical activities for an effective FMD response effort. Therefore, the main purpose of this study was to clarify the relationship between farmers’ knowledge levels and their behaviors to establish a strategy to control FMD. In our study, item count technique was applied to estimate the number of farmers that under-report and sell FMD-infected animals, although to do so is prohibited by law. The following findings were observed: about 63% of farmers have very poor knowledge of routes of FMD transmission; ‘under-reporting’ was found to be a sensitive behavior and nearly 23% of the farmers were reluctant to report FMD-infected animals; and ‘selling FMD-infected animals’ is a sensitive behavior among high-level knowledge group while it is a non-sensitive behavior among the low-level knowledge group. If farmers would understand the importance of prompt reporting, they may report any suspected cases of FMD to veterinary officials. However, even if farmers report honestly, they do not want to cull FMD-infected animals. Thus, education programs should be conducted not only on FMD introduction and transmission, but also its impact. Furthermore, consumers may criticize the farmers for culling their infected animals. Hence, not only farmers, but also consumers need to be educated on the economic impact of FMD and the importance of controlling an outbreak. If farmers have a high knowledge of FMD transmission, they consider selling FMD-infected animals as a sensitive behavior. Therefore, severe punishment should

  7. A Sensitivity Analysis Method to Study the Behavior of Complex Process-based Models

    NASA Astrophysics Data System (ADS)

    Brugnach, M.; Neilson, R.; Bolte, J.

    2001-12-01

    The use of process-based models as a tool for scientific inquiry is becoming increasingly relevant in ecosystem studies. Process-based models are artificial constructs that simulate the system by mechanistically mimicking the functioning of its component processes. Structurally, a process-based model can be characterized, in terms of its processes and the relationships established among them. Each process comprises a set of functional relationships among several model components (e.g., state variables, parameters and input data). While not encoded explicitly, the dynamics of the model emerge from this set of components and interactions organized in terms of processes. It is the task of the modeler to guarantee that the dynamics generated are appropriate and semantically equivalent to the phenomena being modeled. Despite the availability of techniques to characterize and understand model behavior, they do not suffice to completely and easily understand how a complex process-based model operates. For example, sensitivity analysis studies model behavior by determining the rate of change in model output as parameters or input data are varied. One of the problems with this approach is that it considers the model as a "black box", and it focuses on explaining model behavior by analyzing the relationship input-output. Since, these models have a high degree of non-linearity, understanding how the input affects an output can be an extremely difficult task. Operationally, the application of this technique may constitute a challenging task because complex process-based models are generally characterized by a large parameter space. In order to overcome some of these difficulties, we propose a method of sensitivity analysis to be applicable to complex process-based models. This method focuses sensitivity analysis at the process level, and it aims to determine how sensitive the model output is to variations in the processes. Once the processes that exert the major influence in

  8. Thymidine analog methods for studies of adult neurogenesis are not equally sensitive

    PubMed Central

    Leuner, Benedetta; Glasper, Erica R.; Gould, Elizabeth

    2009-01-01

    Adult neurogenesis is often studied by labeling new cells with the thymidine analog bromodeoxyuridine (BrdU) and using immunohistochemical methods for their visualization. Using this approach, considerable variability has been reported in the number of new cells produced in the dentate gyrus of adult rodents. We examined whether immunohistochemical methods, including BrdU antibodies from different vendors (Vector, BD, Roche, Dako, Novocastra, Accurate) and DNA denaturation pretreatments, alter the quantitative and qualitative patterns of BrdU labeling. We also compared the sensitivity and specificity of BrdU with two other thymidine analogs, iododeoxyuridine (IdU) and chlorodeoxyuridine (CldU). We found that the number of BrdU-labeled cells in the dentate gyrus of adult rats was dependent on the BrdU antibody used but was unrelated to differences in antibody penetration. Even at a higher concentration, some antibodies stained fewer cells (Vector, Novocastra). A sensitive BrdU antibody (BD) was specific for dividing cells; all BrdU-labeled cells stained for Ki67, an endogenous marker of cell proliferation. We also observed that DNA denaturation pretreatments affected the number of BrdU-labeled cells and staining intensity for a marker of neuronal differentiation, NeuN. Finally, we found that IdU and CldU, when used at molarities comparable to those that label the maximal number of cells with BrdU, are less sensitive. These data suggest that antibody and thymidine analog selection, as well as the staining procedure employed, can affect the number of newly generated neurons detected in the adult brain thus providing a potential explanation for some of the variability in the adult neurogenesis literature. PMID:19731267

  9. Genome-wide association study identifies a potent locus associated with human opioid sensitivity.

    PubMed

    Nishizawa, D; Fukuda, K; Kasai, S; Hasegawa, J; Aoki, Y; Nishi, A; Saita, N; Koukita, Y; Nagashima, M; Katoh, R; Satoh, Y; Tagami, M; Higuchi, S; Ujike, H; Ozaki, N; Inada, T; Iwata, N; Sora, I; Iyo, M; Kondo, N; Won, M-J; Naruse, N; Uehara-Aoyama, K; Itokawa, M; Koga, M; Arinami, T; Kaneko, Y; Hayashida, M; Ikeda, K

    2014-01-01

    Opioids, such as morphine and fentanyl, are widely used as effective analgesics for the treatment of acute and chronic pain. In addition, the opioid system has a key role in the rewarding effects of morphine, ethanol, cocaine and various other drugs. Although opioid sensitivity is well known to vary widely among individual subjects, several candidate genetic polymorphisms reported so far are not sufficient for fully understanding the wide range of interindividual differences in human opioid sensitivity. By conducting a multistage genome-wide association study (GWAS) in healthy subjects, we found that genetic polymorphisms within a linkage disequilibrium block that spans 2q33.3-2q34 were strongly associated with the requirements for postoperative opioid analgesics after painful cosmetic surgery. The C allele of the best candidate single-nucleotide polymorphism (SNP), rs2952768, was associated with more analgesic requirements, and consistent results were obtained in patients who underwent abdominal surgery. In addition, carriers of the C allele in this SNP exhibited less vulnerability to severe drug dependence in patients with methamphetamine dependence, alcohol dependence, and eating disorders and a lower 'Reward Dependence' score on a personality questionnaire in healthy subjects. Furthermore, the C/C genotype of this SNP was significantly associated with the elevated expression of a neighboring gene, CREB1. These results show that SNPs in this locus are the most potent genetic factors associated with human opioid sensitivity known to date, affecting both the efficacy of opioid analgesics and liability to severe substance dependence. Our findings provide valuable information for the personalized treatment of pain and drug dependence. PMID:23183491

  10. Genome-wide association study identifies a potent locus associated with human opioid sensitivity

    PubMed Central

    Nishizawa, D; Fukuda, K; Kasai, S; Hasegawa, J; Aoki, Y; Nishi, A; Saita, N; Koukita, Y; Nagashima, M; Katoh, R; Satoh, Y; Tagami, M; Higuchi, S; Ujike, H; Ozaki, N; Inada, T; Iwata, N; Sora, I; Iyo, M; Kondo, N; Won, M-J; Naruse, N; Uehara-Aoyama, K; Itokawa, M; Koga, M; Arinami, T; Kaneko, Y; Hayashida, M; Ikeda, K

    2014-01-01

    Opioids, such as morphine and fentanyl, are widely used as effective analgesics for the treatment of acute and chronic pain. In addition, the opioid system has a key role in the rewarding effects of morphine, ethanol, cocaine and various other drugs. Although opioid sensitivity is well known to vary widely among individual subjects, several candidate genetic polymorphisms reported so far are not sufficient for fully understanding the wide range of interindividual differences in human opioid sensitivity. By conducting a multistage genome-wide association study (GWAS) in healthy subjects, we found that genetic polymorphisms within a linkage disequilibrium block that spans 2q33.3–2q34 were strongly associated with the requirements for postoperative opioid analgesics after painful cosmetic surgery. The C allele of the best candidate single-nucleotide polymorphism (SNP), rs2952768, was associated with more analgesic requirements, and consistent results were obtained in patients who underwent abdominal surgery. In addition, carriers of the C allele in this SNP exhibited less vulnerability to severe drug dependence in patients with methamphetamine dependence, alcohol dependence, and eating disorders and a lower ‘Reward Dependence' score on a personality questionnaire in healthy subjects. Furthermore, the C/C genotype of this SNP was significantly associated with the elevated expression of a neighboring gene, CREB1. These results show that SNPs in this locus are the most potent genetic factors associated with human opioid sensitivity known to date, affecting both the efficacy of opioid analgesics and liability to severe substance dependence. Our findings provide valuable information for the personalized treatment of pain and drug dependence. PMID:23183491

  11. Sensitive skin.

    PubMed

    Misery, L; Loser, K; Ständer, S

    2016-02-01

    Sensitive skin is a clinical condition defined by the self-reported facial presence of different sensory perceptions, including tightness, stinging, burning, tingling, pain and pruritus. Sensitive skin may occur in individuals with normal skin, with skin barrier disturbance, or as a part of the symptoms associated with facial dermatoses such as rosacea, atopic dermatitis and psoriasis. Although experimental studies are still pending, the symptoms of sensitive skin suggest the involvement of cutaneous nerve fibres and neuronal, as well as epidermal, thermochannels. Many individuals with sensitive skin report worsening symptoms due to environmental factors. It is thought that this might be attributed to the thermochannel TRPV1, as it typically responds to exogenous, endogenous, physical and chemical stimuli. Barrier disruptions and immune mechanisms may also be involved. This review summarizes current knowledge on the epidemiology, potential mechanisms, clinics and therapy of sensitive skin. PMID:26805416

  12. Aerodynamic parameter studies and sensitivity analysis for rotor blades in axial flight

    NASA Technical Reports Server (NTRS)

    Chiu, Y. Danny; Peters, David A.

    1991-01-01

    The analytical capability is offered for aerodynamic parametric studies and sensitivity analyses of rotary wings in axial flight by using a 3-D undistorted wake model in curved lifting line theory. The governing equations are solved by both the Multhopp Interpolation technique and the Vortex Lattice method. The singularity from the bound vortices is eliminated through the Hadamard's finite part concept. Good numerical agreement between both analytical methods and finite differences methods are found. Parametric studies were made to assess the effects of several shape variables on aerodynamic loads. It is found, e.g., that a rotor blade with out-of-plane and inplane curvature can theoretically increase lift in the inboard and outboard regions respectively without introducing an additional induced drag.

  13. The Low Frequency All Sky Monitor for the Study of Radio Transients: Array Configuration and Sensitivity

    NASA Astrophysics Data System (ADS)

    Miller, Rossina B.; Jenet, F. A.; Hicks, B.; Kassim, N. E.; Ray, P. S.; Taylor, G. B.

    2012-01-01

    The forthcoming Low Frequency All Sky Monitor (LoFASM), will be an array of dipoles working between 10-88 MHz adapted from the Long Wavelength Array (LWA) design. This array will offer significant advantages over other projects for the study of radio transients, but its effectiveness will depend on the geometric details of the array. This poster presents the results of theoretical sensitivity calculations for a single 12 antenna array. An optimal configuration was found that can effectively block terrestrial signals incident from the horizon at certain "resonant" frequencies. This configuration will allow LoFASM to operate in regions with relatively high radio frequency interference. We also discuss possible transient sources that could be studied by this instrument.

  14. Recent changes in surface solar radiation and precipitation in India: sensitivity studies with ECHAM5-HAM

    NASA Astrophysics Data System (ADS)

    Folini, D.; Frischknecht, M.; Wild, M.

    2012-04-01

    Population growth and industrialization is progressing at an unprecedented rate on a global scale. One region undergoing a particularly fast transition is India. These changes are accompanied, among others, by a substantial increase in aerosol emission. To learn more about associated consequences for the climate system we have carried out a comparatively large set of transient sensitivity studies with the global atmosphere only climate model ECHAM5-HAM, using aerosol emission data from NIES (National Institute of Environmental Studies, Japan) and prescribed, observation based sea surface temperatures (SSTs) from the Hadley Center. The sensitivity studies cover the period from 1870 to 2005 and comprise ensembles of simulations (up to 13 members per ensemble), which allow to address the role of different aerosol species, greenhouse gases, and prescribed sea surface temperatures. We present and analysis of these simulation data with particular focus on surface solar radiation (SSR) and precipitation in India, and discuss potential physical mechanisms involved. Modeled annual mean SSR is found to decrease over the Indian subcontinent (land between 67E / 90E / 10N / 25N) at a rate of about -3 to -4 W/m2 per decade. This dimming is roughly in line with observation based estimates. The decrease is comparable under all sky conditions. Regional and seasonal differences are substantial, with the Ganges plane showing the strongest dimming. Aerosols are transported far out over the Indian ocean, leading to a substantial decrease in SSR also there. Modeled precipitation captures well the annual monsoon cycle. The observed, recent decrease in precipitation is, however, overestimated by the model. More precisely, the model captures the observed precipitation reduction in northern India in July / August, but not the observed increase in precipitation in May / June. Our sensitivity studies suggest that the atmosphere only response to increasing aerosol emissions is a reduction of

  15. Microarray study of temperature-dependent sensitivity and selectivity of metal/oxide sensing interfaces

    NASA Astrophysics Data System (ADS)

    Tiffany, Jason; Cavicchi, Richard E.; Semancik, Stephen

    2001-02-01

    Conductometric gas microsensors offer the benefits of ppm-level sensitivity, real-time data, simple interfacing to electronics hardware, and low power consumption. The type of device we have been exploring consists of a sensor film deposited on a "microhotplate"- a 100 micron platform with built-in heating (to activate reactions on the sensing surface) and thermometry. We have been using combinatorial studies of 36-element arrays to characterize the relationship between sensor film composition, operating temperature, and response, as measured by the device's sensitivity and selectivity. Gases that have been tested on these arrays include methanol, ethanol, dichloromethane, propane, methane, acetone, benzene, hydrogen, and carbon monoxide, and are of interest in the management of environmental waste sites. These experiments compare tin oxide films modified by catalyst overlayers, and ultrathin metal seed layers. The seed layers are used as part of a chemical vapor deposition process that uses each array element's microheater to activate the deposition of SnO2, and control its microstructure. Low coverage (20 Ê) catalytic metals (Pd, Cu, Cr, In, Au) are deposited on the oxides by masked evaporation or sputtering. This presentation demonstrates the value of an array-based approach for developing film processing methods, measuring performance characteristics, and establishing reproducibility. It also illustrates how temperature-dependent response data for varied metal/oxide compositions can be used to tailor a microsensor array for a given application.

  16. Hurricane-generated currents on the outer continental shelf. 2. Model sensitivity studies

    NASA Astrophysics Data System (ADS)

    Cooper, Cortis; Thompson, J. Dana

    1989-09-01

    A numerical model described and verified in part 1 of this two-part series (Cooper and Thompson, this issue) is applied to study the sensitivity of hurricane-generated currents on the outer shelf and slope. Numerical experiments are performed in a simple basin with a straight shelf. The sensitivity of the response to changes in storm parameters, direction of storm approach, and topography is quantified. Response is measured in terms of the mixed-layer velocity and depth at sites along the storm track. Results reveal the most important factors are (in decreasing order) wind speed, storm translation speed, direction of storm approach, asymmetry in the wind field, entrainment parameterization, and advection at slower storm translation speeds. Response is largely insensitive (less than 10%) to radius of maximum wind, shelf and slope configuration, bottom friction, atmospheric pressure gradients, and further reductions in the model grid size. For a storm approaching cross shelf, the response is primarily baroclinic (greater than 90%) and only weakly dependent (less than 10%) on the water depth at the site.

  17. Contact allergens in persons with leg ulcers: a Canadian study in contact sensitization.

    PubMed

    Smart, Victoria; Alavi, Afsaneh; Coutts, Pat; Fierheller, Marjorie; Coelho, Sunita; Linn Holness, D; Sibbald, R Gary

    2008-09-01

    Individuals with chronic leg ulcers often develop contact allergic reactions to topical preparations used to treat their wounds and the surrounding skin. The objective of this study was to determine the frequency of positive patch test responses to common allergens in patients with leg ulcers or venous disease. A case series of 100 consecutive, consenting patients with chronic venous disease and other causes of leg ulcers that were available for patch testing were enrolled. The patients were tested with 38 common allergens, including those most relevant to leg ulcers. A total of 46% of the patients had at least 1 positive patch test response. Multiple reactions in the same patient were common. The most frequent groups of sensitizers were fragrances, lanolin, antibacterial agents, and rubber-related allergens. Though the prevalence of positive patch test reactions is high in this population, it is lower than commonly reported. This may be the result of clinical practice that considered the avoidance of common sensitizers in the management of patients with leg ulcers. PMID:18757387

  18. Hypothesis for induction and propagation of chemical sensitivity based on biopsy studies.

    PubMed

    Meggs, W J

    1997-03-01

    The reactive airways dysfunction syndrome (RADS), the reactive upper airways dysfunction syndrome (RUDS), the sick building syndrome (SBS), and the multiple chemical sensitivity syndrome (MCS) are overlapping disorders in which there is an intolerance to environmental chemicals. The onset of these illnesses is often associated with an initial acute chemical exposure. To understand the pathophysiology of these conditions, a study of the nasal pathology of individuals experiencing these syndromes was undertaken. Preliminary data indicate that the nasal pathology of these disorders is characterized by defects in tight junctions between cells, desquamation of the respiratory epithelium, glandular hyperplasia, lymphocytic infiltrates, and peripheral nerve fiber proliferation. These findings suggest a model for a relationship between the chronic inflammation seen in these conditions and an individual's sensitivity to chemicals. A positive feedback loop is set up: the inflammatory response to low levels of chemical irritants is enhanced due to the observed changes in the epithelium, and the epithelial changes are propagated by the inflammatory response to the chemicals. This model, combined with the concept of neurogenic switching, has the potential to explain many aspects of RADS, RUDS, SBS, and MCS in a unified way. PMID:9167982

  19. Nanoscale elemental sensitivity study of Nd₂Fe₁₄B using absorption correlation tomography.

    PubMed

    Kao, Thomas L; Shi, Crystal Y; Wang, Junyue; Mao, Wendy L; Liu, Yijin; Yang, Wenge

    2013-11-01

    Transmission X-ray microscopy (TXM) is a rapidly developing technique with the capability of nanoscale three dimensional (3D) real-space imaging. Combined with the wide range in energy tunability from synchrotron sources, TXM enables the retrieval of 3D microstructural information with elemental/chemical sensitivity that would otherwise be inaccessible. The differential absorption contrast above and below absorption edges has been used to reconstruct the distributions of different elements, assuming the absorption edges of the interested elements are fairly well separated. Here we present an "Absorption Correlation Tomography" (ACT) method based on the correlation of the material absorption across multiple edges. ACT overcomes the significant limitation caused by overlapping absorption edges, significantly expands the capabilities of TXM, and makes it possible for fully quantitative nano-scale 3D structural investigation with chemical/elemental sensitivity. The capability and robustness of this new methodology is demonstrated in a case study of an important type of rare earth magnet (Nd₂Fe₁₄B). PMID:23922210

  20. Host cell reactivation studies with epidermal cells of mice sensitive and resistant to carcinogenesis

    SciTech Connect

    Strickland, J.E.; Strickland, A.G.

    1984-03-01

    Primary epidermal cells from AKR, BALB/c, CD-1, and SENCAR mice, listed in order of least to most sensitive to epidermal carcinogenesis by initiation and promotion protocols, were found to be equally competent to ''reactivate'' herpes simplex virus type 1 irradiated by germicidal ultraviolet radiation. Nontumorigenic BALB/c epidermal cell lines selected in vitro for resistance to terminal differentiation after in vivo or in vitro treatment with initiating doses of carcinogens showed virus survival curves similar to those of primary cells. Similarly, primary cultures which were allowed to grow to confluency following a single treatment with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (100 ng/ml) retained normal host cell reactivation. Host cell reactivation studies with mouse dermal fibroblasts could not be done because of the failure of the herpes simplex virus to infect these cells and produce plaques. These results demonstrate that survival of ultraviolet light-damaged virus in primary epidermal cells in culture is unrelated to whether the cells are derived from mice sensitive or resistant to epidermal carcinogenesis. Furthermore, virus survival is not changed by tumor promoter treatment or by treatment with initiating doses of carcinogens which results in differentiation-resistant cells.

  1. Transport studies of quantum dots sensitized single Mn-ZnO nanowire field effect transistors

    NASA Astrophysics Data System (ADS)

    Sapkota, Keshab R.; Maloney, Francis Scott; Rimal, Gaurab; Poudyal, Uma; Tang, Jinke; Wang, Wenyong

    We present opto-electrical transport properties of Mn-CdSe quantum dots (QDs) sensitized single Mn-ZnO nanowire (NW) field effect transistors (FET). The ZnO NWs with 2 atomic % of Mn doping are grown by chemical vapor deposition. The NWs are ferromagnetic at low temperature. The as grown nanowires are transferred to clean SiO2/Si substrate and single nanowire field effect transistors (FET) are fabricated by standard e-beam lithography. Mobility and carrier concentration of Mn-ZnO NWs are estimated from FET device measurement which shows NWs are n-type semiconductors. Pulse laser deposition of Mn-CdSe QDs on the single NW FET significantly increases carrier concentration of the QD-NW system in dark where the QD monolayer conduction is negligibly small. The photoconductivity study of QD sensitized NW FET enlightens the conduction spectrum of QD-NW system and QD to NW carrier transfer mechanism. This work has been supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award DE-FG02-10ER46728.

  2. Sensitivity Studies for Space-Based Global Measurements of Atmospheric Carbon Dioxide

    NASA Technical Reports Server (NTRS)

    Mao, Jian-Ping; Kawa, S. Randolph; Bhartia, P. K. (Technical Monitor)

    2001-01-01

    Carbon dioxide (CO2) is well known as the primary forcing agent of global warming. Although the climate forcing due to CO2 is well known, the sources and sinks of CO2 are not well understood. Currently the lack of global atmospheric CO2 observations limits our ability to diagnose the global carbon budget (e.g., finding the so-called "missing sink") and thus limits our ability to understand past climate change and predict future climate response. Space-based techniques are being developed to make high-resolution and high-precision global column CO2 measurements. One of the proposed techniques utilizes the passive remote sensing of Earth's reflected solar radiation at the weaker vibration-rotation band of CO2 in the near infrared (approx. 1.57 micron). We use a line-by-line radiative transfer model to explore the potential of this method. Results of sensitivity studies for CO2 concentration variation and geophysical conditions (i.e., atmospheric temperature, surface reflectivity, solar zenith angle, aerosol, and cirrus cloud) will be presented. We will also present sensitivity results for an O2 A-band (approx. 0.76 micron) sensor that will be needed along with CO2 to make surface pressure and cloud height measurements.

  3. Derivation of soil thresholds for lead applying species sensitivity distribution: A case study for root vegetables.

    PubMed

    Ding, Changfeng; Ma, Yibing; Li, Xiaogang; Zhang, Taolin; Wang, Xingxiang

    2016-02-13

    The combination of food quality standard and soil-plant transfer models can be used to derive critical limits of heavy metals for agricultural soils. In this paper, a robust methodology is presented, taking the variations of plant species and cultivars and soil properties into account to derive soil thresholds for lead (Pb) applying species sensitivity distribution (SSD). Three species of root vegetables (four cultivars each for radish, carrot, and potato) were selected to investigate their sensitivity differences for accumulating Pb through greenhouse experiment. Empirical soil-plant transfer model was developed from carrot New Kuroda grown in twenty-one soils covering a wide variation in physicochemical properties and was used to normalize the bioaccumulation data of non-model cultivars. The relationship was then validated to be reliable and would not cause over-protection using data from field experimental sites and published independent studies. The added hazardous concentration for protecting 95% of the cultivars not exceeding the food quality standard (HC5add) were then calculated from the Burr Type III function fitted SSD curves. The derived soil Pb thresholds based on the added risk approach (total soil concentration subtracting the natural background part) were presented as continuous or scenario criteria depending on the combination of soil pH and CEC. PMID:26513560

  4. Sample size calculations for crossover thorough QT studies: satisfaction of regulatory threshold and assay sensitivity.

    PubMed

    Anand, Suraj P; Murray, Sharon C; Koch, Gary G

    2010-05-01

    The cost for conducting a "thorough QT/QTc study" is substantial and an unsuccessful outcome of the study can be detrimental to the safety profile of the drug, so sample size calculations play a very important role in ensuring adequate power for a thorough QT study. Current literature offers some help in designing such studies, but these methods have limitations and mostly apply only in the context of linear mixed models with compound symmetry covariance structure. It is not evident that such models can satisfactorily be employed to represent all kinds of QTc data, and the existing literature inadequately addresses whether there is a change in sample size and power for more general covariance structures for the linear mixed models. We assess the use of some of the existing methods to design a thorough QT study through data arising from a GlaxoSmithKline (GSK)-conducted thorough QT study, and explore newer models for sample size calculation. We also provide a new method to calculate the sample size required to detect assay sensitivity with adequate power. PMID:20358438

  5. Effect of memantine on cough reflex sensitivity: translational studies in guinea pigs and humans.

    PubMed

    Dicpinigaitis, Peter V; Canning, Brendan J; Garner, Rachel; Paterson, Blake

    2015-03-01

    Cough is the most common complaint for which outpatients in the United States seek medical attention, and yet available therapeutic options for cough lack proven efficacy and are further limited by safety and abuse liabilities. Thus, safe and effective cough suppressants are needed. Recent preclinical studies described the antitussive effects of memantine, an N-methyl-d-aspartate receptor channel blocker used in the treatment of Alzheimer's disease. The goals of the present study were to compare the antitussive effects of memantine, dextromethorphan, and codeine in guinea pigs; to relate the dose-dependent actions of memantine in these studies to peak plasma concentrations achieved following oral administration; and to provide the first ever evaluation of the antitussive effect of memantine in humans. In guinea pigs, memantine and codeine were comparable in efficacy and potency but both were superior to dextromethorphan in the citric acid cough challenge model. The pharmacokinetic analyses suggest that memantine was active in guinea pigs at micromolar plasma concentrations. Subsequently, 14 healthy volunteers as well as 14 otherwise healthy adults with acute viral upper respiratory tract infection (URI) underwent capsaicin cough challenges 6 hours after ingestion of 20 mg memantine and matched placebo in a randomized, double-blind, crossover fashion. In healthy volunteers, memantine significantly inhibited cough reflex sensitivity (P = 0.034). In subjects with URI, responsiveness to capsaicin was markedly increased, and in these patients, the inhibition of cough reflex sensitivity by memantine relative to placebo did not reach statistical significance (P = 0.088). These data support further research to investigate the potential of memantine as a clinically useful antitussive. PMID:25525191

  6. Modeling and sensitivity study of the dual-chamber SMART (SMA ReseTtable) lift device

    NASA Astrophysics Data System (ADS)

    Luntz, Jonathan E.; Young, Jonathan R.; Brei, Diann; Radice, Joshua; Strom, Kenneth A.

    2007-04-01

    Morphing structures for applications such as impact mitigation is a challenging problem due to the speed and repeatability requirements that limit the viable actuation approaches. This paper examines a promising stored-energy, active-release approach that can be deployed quickly (~40 ms), is reusable/resetable and can be tuned in the field for changing conditions such as additional mass, temperature compensation or platform changes. The Dual-Chamber SMART (SMA ReseTtable) Lift is a pneumatic air spring controlled via an ultra-fast SMA actuated valve. This paper presents the modeling, sensitivity analysis and experimental validation of this new technology. A control-volume based analytical model was derived that employs compressible, sonic flow and thermodynamic relations to provide a set of differential equations that relate the design parameters (cylinder and valve geometry), application parameters (deployed mass), and operational parameters (pressure, temperature and SMA valve actuation profile), to the deployment performance (deploy time, profile, position, etc.). The model was exercised to explore the sensitivity of the performance with regards to these parameters and explore the off-line and on-line adjustability of the device's performance to compensate for cross platform applications and uncontrolled environmental effects such as temperature and added mass. As proof-of-concept, a full-scale prototype was designed via the model, built and experimentally characterized across several of the parameters for the real case-study of automotive pedestrian protection. The prototype performance agreed closely with model predictions and met the rigorous specifications of the case study with in-situ tailoring which is applicable to a wide range of morphing applications beyond this case study.

  7. Fatigue life prediction for wind turbines: A case study on loading spectra and parameter sensitivity

    SciTech Connect

    Sutherland, H.J.; Veers, P.S.; Ashwill, T.D.

    1992-01-01

    Wind turbines are fatigue-critical machines used to produce electrical energy from the wind. These rotating machines are subjected to environmental loadings that are highly irregular in nature. Historical examples of fatigue problems in both research and commercial wind turbine development are presented. Some example data on wind turbine environments, loadings and material properties are also shown. Before a description of how the authors have chosen to attack the cumulative damage assessment, questions are presented for the reader's reflection. The solution technique used by the authors is then presented, followed by a case study applying the procedures to an actual wind turbine blade joint. The wind turbine is the 34-meter diameter vertical axis wind turbine (VAWT) erected by Sandia National Laboratories near Bushland, Texas. The case study examines parameter sensitivities for realistic uncertainties in inputs defining the turbine environment, stress response and material properties. The fatigue lifetimes are calculated using a fatigue analysis program, called LIFE2, which was developed at Sandia. The LIFE2 code, described in some detail in an appendix, is a PC-based, menu-driven package that leads the user through the steps required to characterize the loading and material properties, then uses Miner's rule or a linear crack propagation rule to numerically calculate the time to failure. Only S-n based cumulative damage applications are illustrated here. The LIFE2 code is available to educational institutions for use as a case study in describing complicated loading histories and for use by students in examining, hands on, parameter sensitivity of fatigue life analysis.

  8. Fatigue life prediction for wind turbines: A case study on loading spectra and parameter sensitivity

    NASA Astrophysics Data System (ADS)

    Sutherland, H. J.; Veers, P. S.; Ashwill, T. D.

    Wind turbines are fatigue-critical machines used to produce electrical energy from the wind. These rotating machines are subjected to environmental loadings that are highly irregular in nature. Historical examples of fatigue problems in both research and commercial wind turbine development are presented. Some example data on wind turbine environments, loadings and material properties are also shown. Before a description of how the authors have chosen to attack the cumulative damage assessment, questions are presented for the reader's reflection. The solution technique used by the authors is then presented, followed by a case study applying the procedures to an actual wind turbine blade joint. The wind turbine is the 34-meter diameter vertical axis wind turbine (VAWT) erected by Sandia National Laboratories near Bushland, Texas. The case study examines parameter sensitivities for realistic uncertainties in inputs defining the turbine environment, stress response and material properties. The fatigue lifetimes are calculated using a fatigue analysis program, called LIFE2, which was developed at Sandia. The LIFE2 code, described in some detail in an appendix, is a PC-based, menu-driven package that leads the user through the steps required to characterize the loading and material properties, then uses Miner's rule or a linear crack propagation rule to numerically calculate the time to failure. Only S-n based cumulative damage applications are illustrated here. The LIFE2 code is available to educational institutions for use as a case study in describing complicated loading histories and for use by students in examining, hands on, parameter sensitivity of fatigue life analysis.

  9. Angiotensin II (de)sensitization: Fluid intake studies with implications for cardiovascular control.

    PubMed

    Daniels, Derek

    2016-08-01

    Cardiovascular disease is the leading cause of death worldwide and hypertension is the most common risk factor for death. Although many anti-hypertensive pharmacotherapies are approved for use in the United States, rates of hypertension have increased over the past decade. This review article summarizes a presentation given at the 2015 meeting of the Society for the Study of Ingestive Behavior. The presentation described work performed in our laboratory that uses angiotensin II-induced drinking as a model system to study behavioral and cardiovascular effects of the renin-angiotensin system, a key component of blood pressure regulation, and a common target of anti-hypertensives. Angiotensin II (AngII) is a potent dipsogen, but the drinking response shows a rapid desensitization after repeated injections of AngII. This desensitization appears to be dependent upon the timing of the injections, requires activation of the AngII type 1 (AT1) receptor, requires activation of mitogen-activated protein (MAP) kinase family members, and involves the anteroventral third ventricle (AV3V) region as a critical site of action. Moreover, the response does not appear to be the result of a more general suppression of behavior, a sensitized pressor response to AngII, or an aversive state generated by the treatment. More recent studies suggest that the treatment regimen used to produce desensitization in our laboratory also prevents the sensitization that occurs after daily bolus injections of AngII. Our hope is that these findings can be used to support future basic research on the topic that could lead to new developments in treatments for hypertension. PMID:26801390

  10. DFT and TD-DFT study on geometries, electronic structures and electronic absorption of some metal free dye sensitizers for dye sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Mohr, T.; Aroulmoji, V.; Ravindran, R. Samson; Müller, M.; Ranjitha, S.; Rajarajan, G.; Anbarasan, P. M.

    2015-01-01

    The geometries, electronic structures, polarizabilities and hyperpolarizabilities of 2-hydroxynaphthalene-1,4-dione (henna1), 3-(5-((1E)-2-(1,4-dihydro-1,4-dioxonaphthalen-3-yloxy) vinyl) thiophen-2-yl)-2-isocyanoacrylic acid (henna2) and anthocyanin dye sensitizers were studied based on density functional theory (DFT) using the hybrid functional B3LYP. The Ultraviolet-Visible (UV-Vis) spectrum was investigated by using a hybrid method which combines the properties and dynamics of many-body in the presence of time-dependent (TD) potentials, i.e. TDSCF-DFT (B3LYP). Features of the electronic absorption spectrum in the visible and near-UV regions were plotted and assigned based on TD-DFT calculations. Due to the absorption, bands of the metal-organic compound are n → π* present. The calculated results suggest that the three lowest energy excited states of the investigated dye sensitizers are due to photoinduced electron transfer processes. The interfacial electron transfer between semiconductor TiO2 electrode and dye sensitizer is owing to an electron injection process from excited dye to the semiconductor's conduction band. The role of linking the henna1 dye with a carboxylic acid via a thiophene bridge was analyzed. The results are that using a stronger π-conjugate bridge as well as a strong donator and acceptor group enhances the efficiency.