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Sample records for active passive smap

  1. NASA Soil Moisture Active Passive (SMAP) Applications

    NASA Astrophysics Data System (ADS)

    Orr, Barron; Moran, M. Susan; Escobar, Vanessa; Brown, Molly E.

    2014-05-01

    The launch of the NASA Soil Moisture Active Passive (SMAP) mission in 2014 will provide global soil moisture and freeze-thaw measurements at moderate resolution (9 km) with latency as short as 24 hours. The resolution, latency and global coverage of SMAP products will enable new applications in the fields of weather, climate, drought, flood, agricultural production, human health and national security. To prepare for launch, the SMAP mission has engaged more than 25 Early Adopters. Early Adopters are users who have a need for SMAP-like soil moisture or freeze-thaw data, and who agreed to apply their own resources to demonstrate the utility of SMAP data for their particular system or model. In turn, the SMAP mission agreed to provide Early Adopters with simulated SMAP data products and pre-launch calibration and validation data from SMAP field campaigns, modeling, and synergistic studies. The applied research underway by Early Adopters has provided fundamental knowledge of how SMAP data products can be scaled and integrated into users' policy, business and management activities to improve decision-making efforts. This presentation will cover SMAP applications including weather and climate forecasting, vehicle mobility estimation, quantification of greenhouse gas emissions, management of urban potable water supply, and prediction of crop yield. The presentation will end with a discussion of potential international applications with focus on the ESA/CEOS TIGER Initiative entitled "looking for water in Africa", the United Nations (UN) Convention to Combat Desertification (UNCCD) which carries a specific mandate focused on Africa, the UN Framework Convention on Climate Change (UNFCCC) which lists soil moisture as an Essential Climate Variable (ECV), and the UN Food and Agriculture Organization (FAO) which reported a food and nutrition crisis in the Sahel.

  2. The Soil Moisture Active Passive (SMAP) applications activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil Moisture Active Passive (SMAP) mission is one of the first-tier satellite missions recommended by the U.S. National Research Council Committee on Earth Science and Applications from Space. The SMAP mission 1 is under development by NASA and is scheduled for launch late in 2014. The SMAP mea...

  3. The Soil Moisture Active and Passive (SMAP) Mission

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil Moisture Active and Passive (SMAP) Mission is one of the first Earth observation satellites being developed by NASA in response to the National Research Council’s Decadal Survey. SMAP will make global measurements of the moisture present at Earth's land surface and will distinguish frozen f...

  4. The Soil Moisture Active and Passive (SMAP) Mission

    NASA Technical Reports Server (NTRS)

    Entekhabi, Dara; Nijoku, Eni G.; ONeill, Peggy E.; Kellogg, Kent H.; Crow, Wade T.; Edelstein, Wendy N.; Entin, Jared K.; Goodman, Shawn D.; Jackson, Thomas J.; Johnson, Joel; Kimball, John; Piepmeier, Jeffrey R.; Koster, Randal D.; McDonald, Kyle C.; Moghaddam, Mahta; Moran, Susan; Reichle, Rolf; Shi, J. C.; Spencer, Michael W.; Thurman, Samuel W.; Tsang, Leung; VanZyl, Jakob

    2009-01-01

    The Soil Moisture Active and Passive (SMAP) Mission is one of the first Earth observation satellites being developed by NASA in response to the National Research Council s Decadal Survey. SMAP will make global measurements of the moisture present at Earth's land surface and will distinguish frozen from thawed land surfaces. Direct observations of soil moisture and freeze/thaw state from space will allow significantly improved estimates of water, energy and carbon transfers between land and atmosphere. Soil moisture measurements are also of great importance in assessing flooding and monitoring drought. SMAP observations can help mitigate these natural hazards, resulting in potentially great economic and social benefits. SMAP soil moisture and freeze/thaw timing observations will also reduce a major uncertainty in quantifying the global carbon balance by helping to resolve an apparent missing carbon sink on land over the boreal latitudes. The SMAP mission concept would utilize an L-band radar and radiometer. These instruments will share a rotating 6-meter mesh reflector antenna to provide high-resolution and high-accuracy global maps of soil moisture and freeze/thaw state every two to three days. The SMAP instruments provide direct measurements of surface conditions. In addition, the SMAP project will use these observations with advanced modeling and data assimilation to provide deeper root-zone soil moisture and estimates of land surface-atmosphere exchanges of water, energy and carbon. SMAP is scheduled for a 2014 launch date

  5. The Soil Moisture Active Passive (SMAP) Applications Activity

    NASA Technical Reports Server (NTRS)

    Brown, Molly E.; Moran, Susan; Escobar, Vanessa; Entekhabi, Dara; O'Neill, Peggy; Njoku, Eni

    2011-01-01

    The Soil Moisture Active Passive (SMAP) mission is one of the first-tier satellite missions recommended by the U.S. National Research Council Committee on Earth Science and Applications from Space. The SMAP mission 1 is under development by NASA and is scheduled for launch late in 2014. The SMAP measurements will allow global and high-resolution mapping of soil moisture and its freeze/thaw state at resolutions from 3-40 km. These measurements will have high value for a wide range of environmental applications that underpin many weather-related decisions including drought and flood guidance, agricultural productivity estimation, weather forecasting, climate predictions, and human health risk. In 2007, NASA was tasked by The National Academies to ensure that emerging scientific knowledge is actively applied to obtain societal benefits by broadening community participation and improving means for use of information. SMAP is one of the first missions to come out of this new charge, and its Applications Plan forms the basis for ensuring its commitment to its users. The purpose of this paper is to outline the methods and approaches of the SMAP applications activity, which is designed to increase and sustain the interaction between users and scientists involved in mission development.

  6. The NASA Soil Moisture Active Passive (SMAP) Mission: Overview

    NASA Technical Reports Server (NTRS)

    O'Neill, Peggy; Entekhabi, Dara; Njoku, Eni; Kellogg, Kent

    2011-01-01

    The Soil Moisture Active Passive (SMAP) mission is one of the first Earth observation satellites being developed by NASA in response to the National Research Council?s Decadal Survey [1]. Its mission design consists of L-band radiometer and radar instruments sharing a rotating 6-m mesh reflector antenna to provide high-resolution and high-accuracy global maps of soil moisture and freeze/thaw state every 2-3 days. The combined active/passive microwave soil moisture product will have a spatial resolution of 10 km and a mean latency of 24 hours. In addition, the SMAP surface observations will be combined with advanced modeling and data assimilation to provide deeper root zone soil moisture and net ecosystem exchange of carbon. SMAP is expected to launch in the late 2014 - early 2015 time frame.

  7. The soil moisture active passive (SMAP) mission and validation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil Moisture Active Passive (SMAP) satellite will be launched by the National Aeronautics and Space Administration in October 2014. This satellite is the culmination of basic research and applications development over the past thirty years. During most of this period, research and development o...

  8. The Soil Moisture Active/Passive Mission (SMAP)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil Moisture Active/Passive (SMAP) mission will deliver global views of soil moisture content and its freeze/thaw state that are critical terrestrial water cycle state variables. Polarized measurements obtained with a shared antenna L-band radar and radiometer system will allow accurate estima...

  9. NASA's Soil Moisture Active Passive (SMAP) Observatory

    NASA Technical Reports Server (NTRS)

    Kellogg, Kent; Thurman, Sam; Edelstein, Wendy; Spencer, Michael; Chen, Gun-Shing; Underwood, Mark; Njoku, Eni; Goodman, Shawn; Jai, Benhan

    2013-01-01

    The SMAP mission will produce high-resolution and accurate global maps of soil moisture and its freeze/thaw state using data from a non-imaging synthetic aperture radar and a radiometer, both operating at L-band.

  10. Spacecraft Environmental Testing SMAP (Soil, Moisture, Active, Passive)

    NASA Technical Reports Server (NTRS)

    Fields, Keith

    2014-01-01

    Testing a complete full up spacecraft to verify it will survive the environment, in which it will be exposed to during its mission, is a formidable task in itself. However, the ''test like you fly'' philosophy sometimes gets compromised because of cost, design and or time. This paper describes the thermal-vacuum and mass properties testing of the Soil Moisture Active Passive (SMAP) earth orbiting satellite. SMAP will provide global observations of soil moisture and freeze/thaw state (the hydrosphere state). SMAP hydrosphere state measurements will be used to enhance understanding of processes that link the water, energy, and carbon cycles, and to extend the capabilities of weather and climate prediction models. It will explain the problems encountered, and the solutions developed, which minimized the risk typically associated with such an arduous process. Also discussed, the future of testing on expensive long lead-time spacecraft. Will we ever reach the ''build and shoot" scenario with minimal or no verification testing?

  11. NASA's Soil Moisture Active and Passive (SMAP) Mission

    NASA Technical Reports Server (NTRS)

    Kellogg, Kent; Njoku, Eni; Thurman, Sam; Edelstein, Wendy; Jai, Ben; Spencer, Mike; Chen, Gun-Shing; Entekhabi, Dara; O'Neill, Peggy; Piepmeier, Jeffrey; Brown, Molly; Savinell, Chris; Entin, Jared; Ianson, Eric

    2010-01-01

    The Soil Moisture Active-Passive (SMAP) Mission is one of the first Earth observation satellites being formulated by NASA in response to the 2007 National Research Council s Decadal Survey. SMAP will make global measurements of soil moisture at the Earth's land surface and its freeze-thaw state. These measurements will allow significantly improved estimates of water, energy and carbon transfers between the land and atmosphere. Soil moisture measurements are also of great importance in assessing flooding and monitoring drought. Knowledge gained from SMAP observations can help mitigate these natural hazards, resulting in potentially great economic and social benefits. SMAP observations of soil moisture and freeze/thaw timing over the boreal latitudes will also reduce a major uncertainty in quantifying the global carbon balance and help to resolve an apparent missing carbon sink over land. The SMAP mission concept will utilize an L-band radar and radiometer sharing a rotating 6-meter mesh reflector antenna flying in a 680 km polar orbit with an 8-day exact ground track repeat aboard a 3-axis stabilized spacecraft to provide high-resolution and high-accuracy global maps of soil moisture and freeze/thaw state every two to three days. In addition, the SMAP project will use these surface observations with advanced modeling and data assimilation to provide estimates of deeper root-zone soil moisture and net ecosystem exchange of carbon. SMAP recently completed its Phase A Mission Concept Study Phase for NASA and transitioned into Phase B (Formulation and Detailed Design). A number of significant accomplishments occurred during this initial phase of mission development. The SMAP project held several open meetings to solicit community feedback on possible science algorithms, prepared preliminary draft Algorithm Theoretical Basis Documents (ATBDs) for each mission science product, and established a prototype algorithm testbed to enable testing and evaluation of the

  12. Fostering Application Opportunites for the NASA Soil Moisture Active Passive (SMAP) Mission

    NASA Technical Reports Server (NTRS)

    Moran, M. Susan; O'Neill, Peggy E.; Entekhabi, Dara; Njoku, Eni G.; Kellogg, Kent H.

    2010-01-01

    The NASA Soil Moisture Active Passive (SMAP) Mission will provide global observations of soil moisture and freeze/thaw state from space. We outline how priority applications contributed to the SMAP mission measurement requirements and how the SMAP mission plans to foster applications and applied science.

  13. NASA Soil Moisture Active Passive (SMAP) Mission Formulation

    NASA Technical Reports Server (NTRS)

    Entekhabi, Dara; Njoku, Eni; ONeill, Peggy; Kellogg, Kent; Entin, Jared

    2011-01-01

    The Soil Moisture Active Passive (SMAP) Mission is one of the first Earth observation satellites being formulated by NASA in response to the 2007 National Research Council s Earth Science Decadal Survey [1]. SMAP s measurement objectives are high-resolution global measurements of near-surface soil moisture and its freeze-thaw state. These measurements would allow significantly improved estimates of water, energy and carbon transfers between the land and atmosphere. The soil moisture control of these fluxes is a key factor in the performance of atmospheric models used for weather forecasts and climate projections. Soil moisture measurements are also of great importance in assessing flooding and monitoring drought. Knowledge gained from SMAP s planned observations can help mitigate these natural hazards, resulting in potentially great economic and societal benefits. SMAP measurements would also yield high resolution spatial and temporal mapping of the frozen or thawed condition of the surface soil and vegetation. Observations of soil moisture and freeze/thaw timing over the boreal latitudes will contribute to reducing a major uncertainty in quantifying the global carbon balance and help resolve an apparent missing carbon sink over land. The SMAP mission would utilize an L-band radar and radiometer sharing a rotating 6-meter mesh reflector antenna (see Figure 1) [2]. The radar and radiometer instruments would be carried onboard a 3-axis stabilized spacecraft in a 680 km polar orbit with an 8-day repeating ground track. The instruments are planned to provide high-resolution and high-accuracy global maps of soil moisture at 10 km resolution and freeze/thaw at 3 km resolution, every two to three days (see Table 1 for a list of science data products). The mission is adopting a number of approaches to identify and mitigate potential terrestrial radio frequency interference (RFI). These approaches are being incorporated into the radiometer and radar flight hardware and

  14. The NASA Soil Moisture Active Passive (SMAP) Mission Formulation

    NASA Technical Reports Server (NTRS)

    Entekhabi, Dara; Njoku, Eni; ONeill, Peggy; Kellogg, Kent; Entin, Jared

    2011-01-01

    The Soil Moisture Active Passive (SMAP) mission is one of the first-tier projects recommended by the U.S. National Research Council Committee on Earth Science and Applications from Space. The SMAP mission is in formulation phase and it is scheduled for launch in 2014. The SMAP mission is designed to produce high-resolution and accurate global mapping of soil moisture and its freeze/thaw state using an instrument architecture that incorporates an L-band (1.26 GHz) radar and an L-band (1.41 GHz) radiometer. The simultaneous radar and radiometer measurements will be combined to derive global soil moisture mapping at 9 [km] resolution with a 2 to 3 days revisit and 0.04 [cm3 cm-3] (1 sigma) soil water content accuracy. The radar measurements also allow the binary detection of surface freeze/thaw state. The project science goals address in water, energy and carbon cycle science as well as provide improved capabilities in natural hazards applications.

  15. NASA’s Soil Moisture Active Passive (SMAP) mission and opportunities for applications users

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil Moisture Active Passive (SMAP) mission is one of four first-tier missions recommended by the National Research Council's Committee on Earth Science and Applications from Space. Set to launch in 2014, SMAP soil moisture and freeze/thaw measurements will have an accuracy, resolution, and glob...

  16. FOSTERING APPLICATIONS OPPORTUNITIES FOR THE NASA SOIL MOISTURE ACTIVE PASSIVE (SMAP) MISSION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil Moisture Active Passive (SMAP) Mission is one of the first Earth observation satellites being developed by NASA in response to the National Research Council’s (NRC’s) Decadal Survey, Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond. SMAP will ma...

  17. Soil Moisture Active Passive (SMAP) Mission Level 4 Carbon (L4_C) Product Specification Document

    NASA Technical Reports Server (NTRS)

    Glassy, Joe; Kimball, John S.; Jones, Lucas; Reichle, Rolf H.; Ardizzone, Joseph V.; Kim, Gi-Kong; Lucchesi, Robert A.; Smith, Edmond B.; Weiss, Barry H.

    2015-01-01

    This is the Product Specification Document (PSD) for Level 4 Surface and Root Zone Soil Moisture (L4_SM) data for the Science Data System (SDS) of the Soil Moisture Active Passive (SMAP) project. The L4_SM data product provides estimates of land surface conditions based on the assimilation of SMAP observations into a customized version of the NASA Goddard Earth Observing System, Version 5 (GEOS-5) land data assimilation system (LDAS). This document applies to any standard L4_SM data product generated by the SMAP Project.

  18. The Soil Moisture Active and Passive (SMAP) Mission: Improving Science Application Tools and Research

    NASA Astrophysics Data System (ADS)

    Escobar, V. M.; Brown, M. E.; Moran, S. M.

    2011-12-01

    NASA depends on the science community to identify and prioritize leading-edge scientific questions and the observations required to answer them. The Soil Moisture Active and Passive (SMAP) Mission has been identified as a priority for NASA's Science Mission Directorate through the most recent decadal survey. Following launch in 2014, SMAP will deliver global maps of soil moisture content and surface freeze/thaw state. Global measurements of these variables are critical for terrestrial hydrologic and carbon cycle applications. The SMAP observatory consists of two multipolarization L-band sensors, a radar and radiometer that share a deployable mesh reflector antenna. The combined observations from the two sensors will allow accurate estimation of soil moisture at spatial scales. The wide-swath (1000 km) measurements will allow global mapping of soil moisture and freeze/thaw state with a 2-3 day revisit frequency and 1-2 day revisit in boreal latitudes. The synergy of active and passive observations enables measurements of soil moisture and freeze/thaw state with unprecedented resolution, sensitivity, area coverage and revisit frequency. SMAP data are valuable for both scientific research and practical applications. SMAP has the potential to drive a diverse range of novel research in drought and flood guidance, agricultural productivity estimation, weather forecasting, climate prediction, human health risk analysis and defense systems. The accuracy, resolution, and global coverage of SMAP soil moisture and freeze/thaw measurements will provide new information for many science and applications disciplines. A SMAP Applications Team will explore ways to measure interaction and integration of SMAP data with the Emergency Management User community of Maryland in order to produce quantitative metrics related to long-term projects, milestone completion, and movement of SMAP products into routine operations for emergency response.

  19. Soil moisture active passive (SMAP) satellite status and cal/val activities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil Moisture Active Passive (SMAP) satellite will be launched by the National Aeronautics and Space Administration in November 2014. This satellite is the culmination of basic research and applications development over the past thirty years. During most of this period, research and development ...

  20. Soil Moisture Active Passive (SMAP) Data and Services at the NASA NSIDC DAAC

    NASA Astrophysics Data System (ADS)

    Leon, Amanda; Jodha Singh Khalsa, Siri; Leslie, Shannon

    2016-04-01

    The NASA Soil Moisture Active Passive (SMAP) mission, launched on 31 January 2015, provides a capability for global mapping of soil moisture and freeze/thaw state with unprecedented accuracy, resolution, and coverage. The SMAP instrument includes both a radiometer and a synthetic aperture radar (SAR) operating at the L-band (1.20-1.41 GHz) and provides global coverage at the equator every 3 days. The SMAP mission will play a critical role in understanding the Earth's water and energy cycles, improving weather and climate forecasting, and developing disaster prediction and monitoring services. The NASA Distributed Active Archive Centers (DAACs) at the National Snow and Ice Data Center (NSIDC) and the Alaska Satellite Facility (ASF) are jointly distributing and supporting SMAP data products. The DAACs draw upon their unique expertise - NSIDC with cryospheric and remotely-sensed soil moisture data and ASF with SAR data - as well as their shared technologies to provide synergistic data access and support for SMAP products. NSIDC DAAC provides distribution and support of the SMAP Level-1 radiometer products, the Level-2 through Level-4 soil moisture products, the Level-3 freeze/thaw product, and the Level-4 carbon net ecosystem exchange product. By leveraging NASA Earth Science Data and Information System (ESDIS) data systems, NSIDC DAAC provide data discovery, access, and visualization services for SMAP that are common across all NASA Earth science data archived at the DAACs. NSIDC DAAC also provides custom services aimed at meeting the unique needs of their SMAP user communities. This presentation strives to educate and expand the SMAP user community as well as engage with current and potential users for areas of opportunity in the support and services that NSIDC DAAC provides.

  1. Soil Moisture Active Passive (SMAP) Data and Services at the NASA NSIDC DAAC

    NASA Astrophysics Data System (ADS)

    Leon, A.; Booker, L.; Leslie, S. R.; Khalsa, S. J. S.; LeFevre, K.

    2015-12-01

    The NASA Soil Moisture Active Passive (SMAP) mission, launched on 31 January 2015, provides a capability for global mapping of soil moisture and freeze/thaw state with unprecedented accuracy, resolution, and coverage. The SMAP instrument includes both a radiometer and a synthetic aperture radar (SAR) operating at the L-band (1.20-1.41 GHz) and provides global coverage at the equator every 3 days. The SMAP mission will play a critical role in understanding the Earth's water and energy cycles, improving weather and climate forecasting, and developing disaster prediction and monitoring services. The NASA Distributed Active Archive Centers (DAACs) at the National Snow and Ice Data Center (NSIDC) and the Alaska Satellite Facility (ASF) are jointly distributing and supporting SMAP data products. The DAACs draw upon their unique expertise - NSIDC with cryospheric and remotely-sensed soil moisture data and ASF with SAR data - as well as their shared technologies to provide synergistic data access and support for SMAP products. NSIDC DAAC provides distribution and support of the SMAP Level-1 radiometer products, the Level-2 through Level-4 soil moisture products, the Level-3 freeze/thaw product, and the Level-4 carbon net ecosystem exchange product. By leveraging NASA Earth Science Data and Information System (ESDIS) data systems, NSIDC DAAC provide data discovery, access, and visualization services for SMAP that are common across all NASA Earth science data archived at the DAACs. NSIDC DAAC also provides custom services aimed at meeting the unique needs of their SMAP user communities. This presentation strives to educate and expand the SMAP user community as well as engage with current and potential users for areas of opportunity in the support and services that NSIDC DAAC provides.

  2. Scanning L-Band Active Passive (SLAP) - Recent Results from an Airborne Simulator for SMAP

    NASA Technical Reports Server (NTRS)

    Kim, Edward

    2015-01-01

    Scanning L-band Active Passive (SLAP) is a recently-developed NASA airborne instrument specially tailored to simulate the new Soil Moisture Active Passive (SMAP) satellite instrument suite. SLAP conducted its first test flights in December, 2013 and participated in its first science campaign-the IPHEX ground validation campaign of the GPM mission-in May, 2014. This paper will present results from additional test flights and science observations scheduled for 2015.

  3. The soil moisture active passive validation experiment 2012 (SMAPVEX12): pre-launch calibration and validation of the SMAP satellite

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The National Aeronautics and Space Administration (NASA) Soil Moisture Active Passive (SMAP) satellite is scheduled for launch in November 2014. In order to develop robust soil moisture retrieval algorithms that fully exploit the unique capabilities of SMAP, algorithm developers had identified a nee...

  4. Pre-Launch phase 2 rehearsal of the calibration and validation of soil moisture active passive (SMAP) geophysical data products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    NASA’s Soil Moisture Active Passive (SMAP) Mission is scheduled for launch in early November 2014. The objective of the mission is global mapping of soil moisture and landscape freeze/thaw state. SMAP utilizes L-band radar and radiometer measurements sharing a rotating 6-meter mesh reflector antenna...

  5. Landscape freeze/thaw retrievals from soil moisture active passive (SMAP) L-band radar measurements

    NASA Astrophysics Data System (ADS)

    Colliander, A.; Derksen, C.

    2015-12-01

    The NASA Soil Moisture Active Passive (SMAP) mission produces a daily landscape freeze/thaw product (L3_FT_A) which provides categorical (frozen, thawed, or [inverse] transitional) classification of the surface state (for land areas north of 45°N) derived from ascending and descending orbits of SMAP high-resolution L-band radar measurements. The FT retrievals are output to 3 km resolution polar and global grids with temporal revisit of 2 days or better north of ~55°N and 3 days or better north of 45°N. The algorithm classifies the land surface freeze/thaw state based on the time series of L-band radar backscatter compared to frozen and thawed reference states. This presentation will describe pre-launch L3_FT_A algorithm implementation and evaluation using NASA/SAC-D Aquarius L-band radar data, and provide an update on the current status of the SMAP L3_FT_A product. In advance of SMAP measurements, the L3_FT_A algorithm was configured and evaluated using Aquarius measurements. While the temporal (weekly) and spatial (~100 km) resolution is much coarser than SMAP, Aquarius provides L-band radar measurements at an incidence angle (normalized to 40 degrees) which is close to SMAP. Evaluation of FT retrievals derived using both Aquarius freeze/thaw references and backscatter time series as inputs identified good agreement during the fall freeze-up period with FT flag agreement (Aquarius versus in situ) exceeding the 80% SMAP mission requirement when summarized on a monthly basis. Disagreement was greater during the spring thaw transition due in part to uncertainty in characterizing the surface state from in situ measurements and backscatter sensitivity to the onset of snow melt, independent of the soil temperature beneath the snowpack. Initial challenges for SMAP derived FT retrievals include the scale difference between the Aquarius references (~100 km) and the SMAP measurements (3 km) which is particularly problematic in areas of complex topography and/or mixed

  6. Soil Moisture Active/Passive (SMAP) Forward Brightness Temperature Simulator

    NASA Technical Reports Server (NTRS)

    Peng, Jinzheng; Peipmeier, Jeffrey; Kim, Edward

    2012-01-01

    The SMAP is one of four first-tier missions recommended by the US National Research Council's Committee on Earth Science and Applications from Space (Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond, Space Studies Board, National Academies Press, 2007) [1]. It is to measure the global soil moisture and freeze/thaw from space. One of the spaceborne instruments is an L-band radiometer with a shared single feedhorn and parabolic mesh reflector. While the radiometer measures the emission over a footprint of interest, unwanted emissions are also received by the antenna through the antenna sidelobes from the cosmic background and other error sources such as the Sun, the Moon and the galaxy. Their effects need to be considered accurately, and the analysis of the overall performance of the radiometer requires end-to-end performance simulation from Earth emission to antenna brightness temperature, such as the global simulation of L-band brightness temperature simulation over land and sea [2]. To assist with the SMAP radiometer level 1B algorithm development, the SMAP forward brightness temperature simulator is developed by adapting the Aquarius simulator [2] with necessary modifications. This poster presents the current status of the SMAP forward brightness simulator s development including incorporating the land microwave emission model and its input datasets, and a simplified atmospheric radiative transfer model. The latest simulation results are also presented to demonstrate the ability of supporting the SMAP L1B algorithm development.

  7. The NASA Soil Moisture Active Passive (SMAP) Mission - Science and Data Product Development Status

    NASA Technical Reports Server (NTRS)

    Nloku, E.; Entekhabi, D.; O'Neill, P.

    2012-01-01

    The Soil Moisture Active Passive (SMAP) mission, planned for launch in late 2014, has the objective of frequent, global mapping of near-surface soil moisture and its freeze-thaw state. The SMAP measurement system utilizes an L-band radar and radiometer sharing a rotating 6-meter mesh reflector antenna. The instruments will operate on a spacecraft in a 685 km polar orbit with 6am/6pm nodal crossings, viewing the surface at a constant 40-degree incidence angle with a 1000-km swath width, providing 3-day global coverage. Data from the instruments will yield global maps of soil moisture and freeze/thaw state at 10 km and 3 km resolutions, respectively, every two to three days. The 10-km soil moisture product will be generated using a combined radar and radiometer retrieval algorithm. SMAP will also provide a radiometer-only soil moisture product at 40-km spatial resolution and a radar-only soil moisture product at 3-km resolution. The relative accuracies of these products will vary regionally and will depend on surface characteristics such as vegetation water content, vegetation type, surface roughness, and landscape heterogeneity. The SMAP soil moisture and freeze/thaw measurements will enable significantly improved estimates of the fluxes of water, energy and carbon between the land and atmosphere. Soil moisture and freeze/thaw controls of these fluxes are key factors in the performance of models used for weather and climate predictions and for quantifYing the global carbon balance. Soil moisture measurements are also of importance in modeling and predicting extreme events such as floods and droughts. The algorithms and data products for SMAP are being developed in the SMAP Science Data System (SDS) Testbed. In the Testbed algorithms are developed and evaluated using simulated SMAP observations as well as observational data from current airborne and spaceborne L-band sensors including data from the SMOS and Aquarius missions. We report here on the development status

  8. The NASA Soil Moisture Active Passive (SMAP) Mission Status and Early Results

    NASA Astrophysics Data System (ADS)

    Entekhabi, D.; Yueh, S. H.; O'Neill, P. E.; Entin, J. K.; Njoku, E. G.; Kellogg, K.

    2015-12-01

    NASA's Soil Moisture Active Passive (SMAP) mission was launched on January 31, 2015. SMAP provides high-resolution, frequent revisit global mapping of soil moisture and freeze/thaw state based on coincident L-band radiometer and L-band radar measurements. The primary science goal of SMAP is to provide new perspectives on how the three fundamental cycles of the Earth system, the water, energy and carbon cycles, are linked together over land. Soil moisture is the key variable that links the three cycles and makes their co-variations synchronous in time. Soil moisture products with varying resolution and coverage are produced from the radiometer alone, radar alone, radiometer-radar combination and data assimilation. In this session the status of the SMAP observatory and early results based on the science data products will be included. The science data acquisition began in May 2015 following several weeks of observatory and instrument commissioning. An intense calibration and validation period followed. Preliminary science products on instrument measurements, soil moisture, landscape frozen or thawed status, and net ecosystem exchange are available at publicly-accessible data archives. The presentation will include early and summary results on the validation of these products. The instrument measurements can also be used to map sea-ice coverage, ocean surface winds and sea surface salinity. Examples of these global retrievals are also presented.

  9. Comparison of airborne passive and active L-band System (PALS) brightness temperature measurements to SMOS observations during the SMAP validation experiment 2012 (SMAPVEX12)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The purpose of SMAP (Soil Moisture Active Passive) Validation Experiment 2012 (SMAPVEX12) campaign was to collect data for the pre-launch development and validation of SMAP soil moisture algorithms. SMAP is a National Aeronautics and Space Administration’s (NASA) satellite mission designed for the m...

  10. The Planned Soil Moisture Active Passive (SMAP) Mission L-Band Radar/Radiometer Instrument

    NASA Technical Reports Server (NTRS)

    Spencer, Michael; Wheeler, Kevin; Chan, Samuel; Piepmeier, Jeffrey; Hudson, Derek; Medeiros, James

    2011-01-01

    The Soil Moisture Active/Passive (SMAP) mission is a NASA mission identified by the NRC 'decadal survey' to measure both soil moisture and freeze/thaw state from space. The mission will use both active radar and passive radiometer instruments at L-Band. In order to achieve a wide swath at sufficiently high resolution for both active and passive channels, an instrument architecture that uses a large rotating reflector is employed. The instrument system has completed the preliminary design review (PDR) stage, and detailed instrument design has begun. In addition to providing an overview of the instrument design, two recent design modifications are discussed: 1) The addition of active thermal control to the instrument spun side to provide a more stable, settable thermal environment for the radiometer electronics, and 2) A 'sequential transmit' strategy for the two radar polarization channels which allows a single high-power amplifier to be used.

  11. Investigating Baseline, Alternative and Copula-based Algorithm for combining Airborne Active and Passive Microwave Observations in the SMAP Context

    NASA Astrophysics Data System (ADS)

    Montzka, C.; Lorenz, C.; Jagdhuber, T.; Laux, P.; Hajnsek, I.; Kunstmann, H.; Entekhabi, D.; Vereecken, H.

    2015-12-01

    The objective of the NASA Soil Moisture Active & Passive (SMAP) mission is to provide global measurements of soil moisture and freeze/thaw states. SMAP integrates L-band radar and radiometer instruments as a single observation system combining the respective strengths of active and passive remote sensing for enhanced soil moisture mapping. Airborne instruments will be a key part of the SMAP validation program. Here, we present an airborne campaign in the Rur catchment, Germany, in which the passive L-band system Polarimetric L-band Multi-beam Radiometer (PLMR2) and the active L-band system F-SAR of DLR were flown simultaneously on the same platform on six dates in 2013. The flights covered the full heterogeneity of the area under investigation, i.e. all types of land cover and experimental monitoring sites with in situ sensors. Here, we used the obtained data sets as a test-bed for the analysis of three active-passive fusion techniques: A) The SMAP baseline algorithm: Disaggregation of passive microwave brightness temperature by active microwave backscatter and subsequent inversion to soil moisture, B), the SMAP alternative algorithm: Estimation of soil moisture by passive sensor data and subsequent disaggregation by active sensor backscatter and C) Copula-based combination of active and passive microwave data. For method C empirical Copulas were generated and theoretical Copulas fitted both on the level of the raw products brightness temperature and backscatter as well as two soil moisture products. Results indicate that the regression parameters for method A and B are dependent on the radar vegetation index (RVI). Similarly, for method C the best performance was gained by generating separate Copulas for individual land use classes. For more in-depth analyses longer time series are necessary as can obtained by airborne campaigns, therefore, the methods will be applied to SMAP data.

  12. Implementation of Active Thermal Control (ATC) for the Soil Moisture Active and Passive (SMAP) Radiometer

    NASA Technical Reports Server (NTRS)

    Mikhaylov, Rebecca; Kwack, Eug; French, Richard; Dawson, Douglas; Hoffman, Pamela

    2014-01-01

    NASA's Earth Observing Soil Moisture Active and Passive (SMAP) Mission is scheduled to launch in November 2014 into a 685 kilometer near-polar, sun-synchronous orbit. SMAP will provide comprehensive global mapping measurements of soil moisture and freeze/thaw state in order to enhance understanding of the processes that link the water, energy, and carbon cycles. The primary objectives of SMAP are to improve worldwide weather and flood forecasting, enhance climate prediction, and refine drought and agriculture monitoring during its three year mission. The SMAP instrument architecture incorporates an L-band radar and an L-band radiometer which share a common feed horn and parabolic mesh reflector. The instrument rotates about the nadir axis at approximately 15 revolutions per minute, thereby providing a conically scanning wide swath antenna beam that is capable of achieving global coverage within three days. In order to make the necessary precise surface emission measurements from space, the electronics and hardware associated with the radiometer must meet tight short-term (instantaneous and orbital) and long-term (monthly and mission) thermal stabilities. Maintaining these tight thermal stabilities is quite challenging because the sensitive electronics are located on a fast spinning platform that can either be in full sunlight or total eclipse, thus exposing them to a highly transient environment. A passive design approach was first adopted early in the design cycle as a low-cost solution. With careful thermal design efforts to cocoon and protect all sensitive components, all stability requirements were met passively. Active thermal control (ATC) was later added after the instrument Preliminary Design Review (PDR) to mitigate the threat of undetected gain glitches, not for thermal-stability reasons. Gain glitches are common problems with radiometers during missions, and one simple way to avoid gain glitches is to use the in-flight set point programmability that ATC

  13. Assessment of the SMAP level 2 passive soil moisture product

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The NASA Soil Moisture Active Passive (SMAP) satellite mission was launched on Jan 31, 2015. The observatory was developed to provide global mapping of high-resolution soil moisture and freeze-thaw state every 2–3 days using an L-band (active) radar and an L-band (passive) radiometer. SMAP provides ...

  14. Soil Moisture Active Passive (SMAP) Microwave Radiometer Radio-Frequency Interference (RFI) Mitigation: Initial On-Orbit Results

    NASA Technical Reports Server (NTRS)

    Mohammed, Priscilla N.; Piepmeier, Jeffrey R.; Johnson, Joel T.; Aksoy, Mustafa; Bringer, Alexandra

    2015-01-01

    The Soil Moisture Active Passive (SMAP) mission, launched in January 2015, provides global measurements of soil moisture using a microwave radiometer. SMAPs radiometer passband lies within the passive frequency allocation. However, both unauthorized in-band transmitters as well as out-of-band emissions from transmitters operating at frequencies adjacent to this allocated spectrum have been documented as sources of radio frequency interference (RFI) to the L-band radiometers on SMOS and Aquarius. The spectral environment consists of high RFI levels as well as significant occurrences of low level RFI equivalent to 0.1 to 10 K. The SMAP ground processor reports the antenna temperature both before and after RFI mitigation is applied. The difference between these quantities represents the detected RFI level. The presentation will review the SMAP RFI detection and mitigation procedure and discuss early on-orbit RFI measurements from the SMAP radiometer. Assessments of global RFI properties and source types will be provided, as well as the implications of these results for SMAP soil moisture measurements.

  15. Soil Moisture Active Passive (SMAP) Project Algorithm Theoretical Basis Document SMAP L1B Radiometer Data Product: L1B_TB

    NASA Technical Reports Server (NTRS)

    Piepmeier, Jeffrey; Mohammed, Priscilla; De Amici, Giovanni; Kim, Edward; Peng, Jinzheng; Ruf, Christopher; Hanna, Maher; Yueh, Simon; Entekhabi, Dara

    2016-01-01

    The purpose of the Soil Moisture Active Passive (SMAP) radiometer calibration algorithm is to convert Level 0 (L0) radiometer digital counts data into calibrated estimates of brightness temperatures referenced to the Earth's surface within the main beam. The algorithm theory in most respects is similar to what has been developed and implemented for decades for other satellite radiometers; however, SMAP includes two key features heretofore absent from most satellite borne radiometers: radio frequency interference (RFI) detection and mitigation, and measurement of the third and fourth Stokes parameters using digital correlation. The purpose of this document is to describe the SMAP radiometer and forward model, explain the SMAP calibration algorithm, including approximations, errors, and biases, provide all necessary equations for implementing the calibration algorithm and detail the RFI detection and mitigation process. Section 2 provides a summary of algorithm objectives and driving requirements. Section 3 is a description of the instrument and Section 4 covers the forward models, upon which the algorithm is based. Section 5 gives the retrieval algorithm and theory. Section 6 describes the orbit simulator, which implements the forward model and is the key for deriving antenna pattern correction coefficients and testing the overall algorithm.

  16. The Soil Moisture Active and Passive Mission (SMAP): Science and Applications

    NASA Technical Reports Server (NTRS)

    Entekhabi, Dara; O'Neill, Peggy; Njoku, Eni

    2009-01-01

    The Soil Moisture Active and Passive mission (SMAP) will provide global maps of soil moisture content and surface freeze/thaw state. Global measurements of these variables are critical for terrestrial water and carbon cycle applications. The SMAP observatory consists of two multipolarization L-band sensors, a radar and radiometer, that share a deployable-mesh reflector antenna. The combined observations from the two sensors will allow accurate estimation of soil moisture at hydrometeorological (10 km) and hydroclimatological (40 km) spatial scales. The rotating antenna configuration provides conical scans of the Earth surface at a constant look angle. The wide-swath (1000 km) measurements will allow global mapping of soil moisture and its freeze/thaw state with 2-3 days revisit. Freeze/thaw in boreal latitudes will be mapped using the radar at 3 km resolution with 1-2 days revisit. The synergy of active and passive observations enables measurements of soil moisture and freeze/thaw state with unprecedented resolution, sensitivity, area coverage and revisit.

  17. Application oft triple collocation in ground-based validation of soil moisture active/passive (SMAP) level 2 data products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The validation of the soil moisture retrievals from the recently-launched NASA Soil Moisture Active/Passive (SMAP) satellite is important prior to their full public release. Uncertainty in attempts to characterize footprint-scale surface-layer soil moisture using point-scale ground observations has ...

  18. The soil moisture active/passive (SMAP) mission: How we got here and what it will provide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil Moisture Active Passive (SMAP) satellite will be launched by the National Aeronautics and Space Administration in October 2014. This satellite is the culmination of basic research and applications development over the past thirty years. During most of this period, research and development o...

  19. Temperature Knowledge and Model Correlation for the Soil Moisture Active and Passive (SMAP) Reflector Mesh

    NASA Technical Reports Server (NTRS)

    Mikhaylov, Rebecca; Dawson, Douglas; Kwack, Eug

    2014-01-01

    NASA's Earth observing Soil Moisture Active & Passive (SMAP) Mission is scheduled to launch in November 2014 into a 685 km near-polar, sun synchronous orbit. SMAP will provide comprehensive global mapping measurements of soil moisture and freeze/thaw state in order to enhance understanding of the processes that link the water, energy, and carbon cycles. The primary objectives of SMAP are to improve worldwide weather and flood forecasting, enhance climate prediction, and refine drought and agriculture monitoring during its 3 year mission. The SMAP instrument architecture incorporates an L-band radar and an L-band radiometer which share a common feed horn and parabolic mesh reflector. The instrument rotates about the nadir axis at approximately 15 rpm, thereby providing a conically scanning wide swath antenna beam that is capable of achieving global coverage within 3 days. In order to make the necessary precise surface emission measurements from space, a temperature knowledge of 60 deg C for the mesh reflector is required. In order to show compliance, a thermal vacuum test was conducted using a portable solar simulator to illuminate a non flight, but flight-like test article through the quartz window of the vacuum chamber. The molybdenum wire of the antenna mesh is too fine to accommodate thermal sensors for direct temperature measurements. Instead, the mesh temperature was inferred from resistance measurements made during the test. The test article was rotated to five separate angles between 10 deg and 90 deg via chamber breaks to simulate the maximum expected on-orbit solar loading during the mission. The resistance measurements were converted to temperature via a resistance versus temperature calibration plot that was constructed from data collected in a separate calibration test. A simple thermal model of two different representations of the mesh (plate and torus) was created to correlate the mesh temperature predictions to within 60 deg C. The on-orbit mesh

  20. Monte Carlo Analysis of the Commissioning Phase Maneuvers of the Soil Moisture Active Passive (SMAP) Mission

    NASA Technical Reports Server (NTRS)

    Williams, Jessica L.; Bhat, Ramachandra S.; You, Tung-Han

    2012-01-01

    The Soil Moisture Active Passive (SMAP) mission will perform soil moisture content and freeze/thaw state observations from a low-Earth orbit. The observatory is scheduled to launch in October 2014 and will perform observations from a near-polar, frozen, and sun-synchronous Science Orbit for a 3-year data collection mission. At launch, the observatory is delivered to an Injection Orbit that is biased below the Science Orbit; the spacecraft will maneuver to the Science Orbit during the mission Commissioning Phase. The delta V needed to maneuver from the Injection Orbit to the Science Orbit is computed statistically via a Monte Carlo simulation; the 99th percentile delta V (delta V99) is carried as a line item in the mission delta V budget. This paper details the simulation and analysis performed to compute this figure and the delta V99 computed per current mission parameters.

  1. Soil moisture estimation by airborne active and passive microwave remote sensing: A test-bed for SMAP fusion algorithms

    NASA Astrophysics Data System (ADS)

    Montzka, Carsten; Bogena, Heye; Jagdhuber, Thomas; Hajnsek, Irena; Horn, Ralf; Reigber, Andreas; Hasan, Sayeh; Rüdiger, Christoph; Jaeger, Marc; Vereecken, Harry

    2014-05-01

    The objective of the NASA Soil Moisture Active & Passive (SMAP) mission is to provide global measurements of soil moisture and its freeze/thaw state. The SMAP launch is currently planned for 2014-2015. The SMAP measurement approach is to integrate L-band radar and L-band radiometer as a single observation system combining the respective strengths of active and passive remote sensing for enhanced soil moisture mapping. The radar and radiometer measurements can be effectively combined to derive soil moisture maps that approach the accuracy of radiometer-only retrievals, but with a higher resolution (being able to approach the radar resolution under some conditions). Aircraft and tower-based instruments will be a key part of the SMAP validation program. Here, we present an airborne campaign in the Rur catchment in Germany, in which the passive L-band system Polarimetric L-band Multi-beam Radiometer (PLMR2) and the active L-band system DLR F-SAR were flown on six dates in 2013. The flights covered the full heterogeneity of the area under investigation, i.e. all types of land cover and experimental monitoring sites. These data are used as a test-bed for the analysis of existing and development of new active-passive fusion techniques. A synergistic use of the two signals can help to decouple soil moisture effects from the effects of vegetation (or roughness) in a better way than in the case of a single instrument. In this study, we present and evaluate three approaches for the fusion of active and passive microwave records for an enhanced representation of the soil moisture status: i) estimation of soil moisture by passive sensor data and subsequent disaggregation by active sensor backscatter data, ii) disaggregation of passive microwave brightness temperature by active microwave backscatter and subsequent inversion to soil moisture, and iii) fusion of two single-source soil moisture products from radar and radiometer.

  2. Soil Moisture Active Passive (SMAP) Mission Level 4 Surface and Root Zone Soil Moisture (L4_SM) Product Specification Document

    NASA Technical Reports Server (NTRS)

    Reichle, Rolf H.; Ardizzone, Joseph V.; Kim, Gi-Kong; Lucchesi, Robert A.; Smith, Edmond B.; Weiss, Barry H.

    2015-01-01

    This is the Product Specification Document (PSD) for Level 4 Surface and Root Zone Soil Moisture (L4_SM) data for the Science Data System (SDS) of the Soil Moisture Active Passive (SMAP) project. The L4_SM data product provides estimates of land surface conditions based on the assimilation of SMAP observations into a customized version of the NASA Goddard Earth Observing System, Version 5 (GEOS-5) land data assimilation system (LDAS). This document applies to any standard L4_SM data product generated by the SMAP Project. The Soil Moisture Active Passive (SMAP) mission will enhance the accuracy and the resolution of space-based measurements of terrestrial soil moisture and freeze-thaw state. SMAP data products will have a noteworthy impact on multiple relevant and current Earth Science endeavors. These include: Understanding of the processes that link the terrestrial water, the energy and the carbon cycles, Estimations of global water and energy fluxes over the land surfaces, Quantification of the net carbon flux in boreal landscapes Forecast skill of both weather and climate, Predictions and monitoring of natural disasters including floods, landslides and droughts, and Predictions of agricultural productivity. To provide these data, the SMAP mission will deploy a satellite observatory in a near polar, sun synchronous orbit. The observatory will house an L-band radiometer that operates at 1.40 GHz and an L-band radar that operates at 1.26 GHz. The instruments will share a rotating reflector antenna with a 6 meter aperture that scans over a 1000 km swath.

  3. Scanning L-Band Active Passive (SLAP)—FLIGHT Results from a New Airborne Simulator for Smap

    NASA Astrophysics Data System (ADS)

    Kim, E. J.; Faulkner, T.; Wu, A.; Patel, H.

    2014-12-01

    1. Introduction and BackgroundThis paper introduces a new NASA airborne instrument, the Scanning L-band Active Passive (SLAP), which is specially tailored to simulate SMAP. 2. Description of SLAPSLAP has both passive (radiometer) and active (radar) microwave L-band imaging capabilities. The radiometer observes at 1.4 GHz using duplicate front end hardware from the SMAP satellite radiometer. It also includes a duplicate of the digital backend development unit for SMAP, thus the novel Radio Frequency Interference (RFI) detection and mitigation features and algorithms for SMAP are duplicated with very high fidelity in SLAP. The digital backend provides 4-Stokes polarization capability. The real-aperture radar operates in the 1215-1300 MHz band with quad-pol capability. Radar and radiometer share one antenna via diplexers that are spare units from the Aquarius satellite instrument. 3. Flight ResultsSLAP's initial flights were conducted in Dec 2013 over the eastern shore of Maryland and successfully demonstrated radiometer imaging over 2 full SMAP 36x36 km grid cells at 1km resolution within 3 hrs, easily meeting the SMAP post-launch cal/val airborne mapping requirements. A second flight on the same day also demonstrated SLAP's quick-turn abilities and high-resolution/wide-swath capabilities with 200m resolution across a 1500m swath from 2000 ft AGL. Additional flights were conducted as part of the GPM iPHEX campaign in May, 2014. 4. ConclusionThis paper presents flight data and imagery, as well as details of the radiometer and radar performance and calibration. The paper will also describe the mission performance achievable on the King Air and other platforms.

  4. Cost-Effective Telemetry and Command Ground Systems Automation Strategy for the Soil Moisture Active Passive (SMAP) Mission

    NASA Technical Reports Server (NTRS)

    Choi, Joshua S.; Sanders, Antonio L.

    2012-01-01

    Soil Moisture Active Passive (SMAP) is an Earth-orbiting, remote-sensing NASA mission slated for launch in 2014.[double dagger] The ground data system (GDS) being developed for SMAP is composed of many heterogeneous subsystems, ranging from those that support planning and sequencing to those used for real-time operations, and even further to those that enable science data exchange. A full end-to-end automation of the GDS may result in cost savings during mission operations, but it would require a significant upfront investment to develop such comprehensive automation. As demonstrated by the Jason-1 and Wide-field Infrared Survey Explorer (WISE) missions, a measure of "lights-out" automation for routine, orbital pass ground operations can still reduce mission cost through smaller staffing of operators and limited work hours. The challenge, then, for the SMAP GDS engineering team is to formulate an automated operations strategy--and corresponding system architecture--to minimize operator intervention during operations, while balancing the development cost associated with the scope and complexity of automation. This paper discusses the automated operations approach being developed for the SMAP GDS. The focus is on automating the activities involved in routine passes, which limits the scope to real-time operations. A key subsystem of the SMAP GDS--NASA's AMMOS Mission Data Processing and Control System (AMPCS)--provides a set of capabilities that enable such automation. Also discussed are the lights-out pass automations of the Jason-1 and WISE missions and how they informed the automation strategy for SMAP. The paper aims to provide insights into what is necessary in automating the GDS operations for Earth satellite missions.

  5. Cost-Effective Telemetry and Command Ground Systems Automation Strategy for the Soil Moisture Active Passive (SMAP) Mission

    NASA Technical Reports Server (NTRS)

    Choi, Josh; Sanders, Antonio

    2012-01-01

    Soil Moisture Active Passive (SMAP) is an Earth-orbiting, remote-sensing NASA mission slated for launch in 2014. The ground data system (GDS) being developed for SMAP is composed of many heterogeneous subsystems, ranging from those that support planning and sequencing to those used for real-time operations, and even further to those that enable science data exchange. A full end-to-end automation of the GDS may result in cost savings during mission operations, but it would require a significant upfront investment to develop such a comprehensive automation. As demonstrated by the Jason-1 and Wide-field Infrared Survey Explorer (WISE) missions, a measure of "lights-out" automation for routine, orbital pass, ground operations can still reduce mission costs through smaller staffing of operators and limiting their working hours. The challenge, then, for the SMAP GDS engineering team, is to formulate an automated operations strategy--and corresponding system architecture -- to minimize operator intervention during routine operations, while balancing the development costs associated with the scope and complexity of automation. This paper discusses the automated operations approach being developed for the SMAP GDS. The focus is on automating the activities involved in routine passes, which limits the scope to real-time operations. A key subsystem of the SMAP GDS -- NASA's AMMOS Mission Data Processing and Control System (AMPCS) -- provides a set of capabilities that enable such automation. Also discussed are the lights-out pass automations of the Jason-1 and WISE missions and how they informed the automation strategy for SMAP. The paper aims to provide insights into what is necessary in automating the GDS operations for Earth satellite missions.

  6. Pre-Launch Phase 1 Calibration and Validation Rehearsal of Geophysical Data Products of Soil Moisture Active Passive (SMAP) Mission

    NASA Astrophysics Data System (ADS)

    Colliander, A.; Jackson, T. J.; Chan, S.; Dunbar, R.; Das, N. N.; Kim, S.; Reichle, R. H.; De Lannoy, G. J.; Liu, Q.; Kimball, J. S.; Yi, Y.; Cosh, M. H.; Bindlish, R.; Crow, W. T.; Dang, L.; Yueh, S. H.; Njoku, E. G.

    2013-12-01

    NASA's Soil Moisture Active Passive (SMAP) Mission is scheduled for launch in October 2014. The objective of the mission is global mapping of soil moisture and freeze/thaw state. SMAP utilizes an L-band radar and radiometer sharing a rotating 6-meter mesh reflector antenna. The instruments will operate onboard the SMAP spacecraft in a 685-km Sun-synchronous near-polar orbit, viewing the surface at a constant 40-degree incidence angle with a 1000-km swath width. Merging of active and passive L-band observations of the mission will enable an unprecedented combination of accuracy, resolution, coverage and revisit-time for soil moisture and freeze/thaw state retrieval. SMAP measurements will enable significantly improved estimates of water, energy and carbon transfers between the land and atmosphere. The SMAP science data product suite of geophysical parameters will include estimates of surface (top 5 cm) and root-zone (down to 1-m depth) soil moisture, net ecosystem exchange, and classification of the frozen/non-frozen state of the landscape. The primary validation reference of the data products will be ground-based measurements. Other remote sensing and model-based products will be used as additional resources. The post-launch timeline of the mission requires that the geophysical data products are validated (with respect to the mission requirements) within 12 months after a 3-month in-orbit check-out phase. SMAP is taking several preparatory steps in order to meet this schedule. One of the main steps consists of running a rehearsal to exercise calibration and validation procedures planned for the Cal/Val Phase. The rehearsal is divided into two stages. Phase 1, which was conducted in June-August 2013, focused on validation methodologies for the geophysical data products. Phase 2, which will be conducted in May-June 2014, includes operational aspects including a fully functioning SMAP Science Data System. (Note that the rehearsals do not include an airborne field

  7. The Soil Moisture Active Passive (SMAP): Radar Measurements at High Latitudes and of Freeze/Thaw State

    NASA Technical Reports Server (NTRS)

    Spencer, Michael; Dunbar, Scott; Chen, Curtis

    2013-01-01

    The Soil Moisture Active/Passive (SMAP) mission is scheduled for a late 2014 launch date. The mission will use both active radar and passive radiometer instruments at L-Band. In order to achieve a wide swath at sufficiently high resolution for both active and passive channels, an instrument architecture that uses a large rotating reflector is employed. In this paper, a focus will be places on the radar design and associated data products at high latitudes. The radar will employ synthetic-aperture processing to achieve a "moderate" resolution dual-pol product over a 1000 km swath. Because the radar is operating continuously, very frequent temporal coverage will be achieved at high latitudes. This data will be used, among other things, to produce a surface freeze/thaw state data product.

  8. The Soil Moisture Active Passive (SMAP) Radar: Measurements at High Latitudes and of Surface Freeze/Thaw State

    NASA Technical Reports Server (NTRS)

    Spencer, Michael; Dunbar, Scott; Chen, Curtis

    2013-01-01

    The Soil Moisture Active/Passive (SMAP) mission is scheduled for a late 2014 launch date. The mission will use both active radar and passive radiometer instruments at L-Band in order to achieve the science objectives of measuring soil moisture and land surface freeze-thaw state. To achieve requirements for a wide swath at sufficiently high resolution for both active and passive channels, an instrument architecture that uses a large rotating reflector is employed. In this paper, focus will be placed on the radar design. The radar will employ synthetic-aperture processing to achieve a "moderate" resolution dual-pol product over a 1000 km swath. Because the radar is operating continuously, very frequent temporal coverage will be achieved at high latitudes. This data will be used to produce a surface freeze/thaw state data product.

  9. Active–passive soil moisture retrievals during the SMAP validation experiment 2012

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The goal of this study is to assess the performance of the active–passive algorithm for the NASA Soil Moisture Active Passive mission (SMAP) using airborne and ground observations from a field campaign. The SMAP active–passive algorithm disaggregates the coarse-resolution radiometer brightness tempe...

  10. Soil Moisture Active Passive (SMAP) L-Band Microwave Radiometer Post-Launch Calibration

    NASA Technical Reports Server (NTRS)

    Peng, Jinzheng; Piepmeier, Jeffrey R.; Misra, Sidharth; Dinnat, Emmanuel P.; Hudson, Derek; Le Vine, David M.; De Amici, Giovanni; Mohammed, Priscilla N.; Yueh, Simon H.; Meissner, Thomas

    2016-01-01

    The SMAP microwave radiometer is a fully-polarimetric L-band radiometer flown on the SMAP satellite in a 6 AM/ 6 PM sun-synchronous orbit at 685 km altitude. Since April, 2015, the radiometer is under calibration and validation to assess the quality of the radiometer L1B data product. Calibration methods including the SMAP L1B TA2TB (from Antenna Temperature (TA) to the Earth's surface Brightness Temperature (TB)) algorithm and TA forward models are outlined, and validation approaches to calibration stability/quality are described in this paper including future work. Results show that the current radiometer L1B data satisfies its requirements.

  11. Advances in downscaling soil moisture for use in drought and flood assessments: Implications for data from the Soil Moisture Active and Passive (SMAP) Mission

    NASA Astrophysics Data System (ADS)

    Lakshmi, V.; Fang, B.; Narayan, U.

    2015-12-01

    Hydrological hazards, namely droughts and floods are dependent on the deficit and excess of soil moisture. With the launch of the Soil Moisture Active and Passive Mission (SMAP) in January 2015 we will have twice a day global observations of soil moisture. However the spatial resolution of soil moisture retrieved from the SMAP radiometer is 10s of km and the SMAP radar will provide backscatter observations 100m-1km. High spatial resolution of soil moisture helps to monitor floods and droughts in a spatially distributed fashion. The current focus is finding the best way to obtain high spatial resolution soil moisture using the radar and radiometer observations. In this presentation we will deal with downscaling by couple of methods - (a) Use of the thermal inertia relation between soil moisture and surface temperature modulated by vegetation (b) Relationship between soil moisture and evaporation (c) Change detection using high spatial resolution active radar data.

  12. The NASA Soil Moisture Active Passive (SMAP) Mission - Algorithm and Cal/Val Activities and Synergies with SMOS and Other L-Band Missions

    NASA Technical Reports Server (NTRS)

    Njoku, Eni; Entekhabi, Dara; O'Neill, Peggy; Jackson, Tom; Kellogg, Kent; Entin, Jared

    2011-01-01

    NASA's Soil Moisture Active Passive (SMAP) mission, planned for launch in late 2014, has as its key measurement objective the frequent, global mapping of near-surface soil moisture and its freeze-thaw state. SMAP soil moisture and freeze/thaw measurements at 10 km and 3 km resolutions respectively, would enable significantly improved estimates of water, energy and carbon transfers between the land and atmosphere. Soil moisture control of these fluxes is a key factor in the performance of atmospheric models used for weather forecasts and climate projections Soil moisture measurements are also of great importance in assessing floods and for monitoring drought. In addition, observations of soil moisture and freeze/thaw timing over the boreal latitudes can help reduce uncertainties in quantifying the global carbon balance. The SMAP measurement concept utilizes an L-band radar and radiometer sharing a rotating 6-meter mesh reflector antenna. The SMAP radiometer and radar flight hardware and ground processing designs are incorporating approaches to identify and mitigate potential terrestrial radio frequency interference (RFI). The radar and radiometer instruments are planned to operate in a 680 km polar orbit, viewing the surface at a constant 40-degree incidence angle with a 1000-km swath width, providing 3-day global coverage. Data from the instruments would yield global maps of soil moisture and freeze/thaw state to be provided at 10 km and 3 km resolutions respectively, every two to three days. Plans are to provide also a radiometer-only soil moisture product at 40-km spatial resolution. This product and the underlying brightness temperatures have characteristics similar to those provided by the Soil Moisture and Ocean Salinity (SMOS) mission. As a result, there are unique opportunities for common data product development and continuity between the two missions. SMAP also has commonalities with other satellite missions having L-band radiometer and/or radar sensors

  13. Development of SMAP Mission Cal/Val Activities

    NASA Technical Reports Server (NTRS)

    Colliander, A.; Jackson, T.; Kimball, J.; Cosh, M.; Spencer, M.; Entekhabi, D.; Njoku, E.; ONeill, P.

    2010-01-01

    The Soil Moisture Active Passive (SMAP) mission is a NASA directed mission to map global land surface soil moisture and freeze-thaw state. Instrument and mission details are shown. The key SMAP soil moisture product is provided at 10 km resolution with 0.04cubic cm/cubic cm accuracy. The freeze/thaw product is provided at 3 km resolution and 80% frozen-thawed classification accuracy. The full list of SMAP data products is shown.

  14. PALS (Passive Active L-band System) Radiometer-Based Soil Moisture Retrieval for the SMAP Validation Experiment 2012 (SMAPVEX12)

    NASA Astrophysics Data System (ADS)

    Colliander, A.; Jackson, T. J.; Chan, S.; Bindlish, R.; O'Neill, P. E.; Chazanoff, S. L.; McNairn, H.; Bullock, P.; Powers, J.; Wiseman, G.; Berg, A. A.; Magagi, R.; Njoku, E. G.

    2014-12-01

    NASA's (National Aeronautics and Space Administration) Soil Moisture Active Passive (SMAP) mission is scheduled for launch in early January 2015. For pre-launch soil moisture algorithm development and validation, the SMAP project and NASA coordinated a SMAP Validation Experiment 2012 (SMAPVEX12) together with Agriculture and Agri-Food Canada in the vicinity of Winnipeg, Canada in June 7-July 19, 2012. Coincident active and passive airborne L-band data were acquired using the Passive Active L-band System (PALS) on 17 days during the experiment. Simultaneously with the PALS measurements, soil moisture ground truth data were collected manually. The vegetation and surface roughness were sampled on non-flight days. The SMAP mission will produce surface (top 5 cm) soil moisture products a) using a combination of its L-band radiometer and SAR (Synthetic Aperture Radar) measurements, b) using the radiometer measurement only, and c) using the SAR measurements only. The SMAPVEX12 data are being utilized for the development and testing of the algorithms applied for generating these soil moisture products. This talk will focus on presenting results of retrieving surface soil moisture using the PALS radiometer. The issues that this retrieval faces are very similar to those faced by the global algorithm using the SMAP radiometer. However, the different spatial resolution of the two observations has to be accounted for in the analysis. The PALS 3 dB footprint in the experiment was on the order of 1 km, whereas the SMAP radiometer has a footprint of about 40 km. In this talk forward modeled brightness temperature over the manually sampled fields and the retrieved soil moisture over the entire experiment domain are presented and discussed. In order to provide a retrieval product similar to that of the SMAP passive algorithm, various ancillary information had to be obtained for the SMAPVEX12 domain. In many cases there are multiple options on how to choose and reprocess these data

  15. Improving government decision making in response to floods using soil moisture observations from Soil Moisture Active Passive (SMAP) data

    NASA Astrophysics Data System (ADS)

    Escobar, V. M.; Schumann, G.; Torak, L. J.

    2014-12-01

    NASA's Soil Moisture Active Passive (SMAP) Mission, due to launch January 2015, will provide global observations of the Earth's surface soil moisture, providing high accuracy, resolution and continuous global coverage. This paper seeks to show how SMAP data can be used in flood applications to improve flood warning/planning operations for the Upper Mississippi River basin. The Mississippi River ranks as the fourth longest and tenth largest river in the world and is noted as one of the most altered rivers in the United States. The Mississippi River has a very long track record of flood events, with the 2011 event being a unique event due to large volumes of snow melt and heavy spring rain in the Upper Mississippi basin. Understanding and modeling these processes and combining them with relevant satellite observations such as soil moisture conditions could help alleviate some of the risk to flooding by identifying when infiltration to soils is cut off causing excessive runoff. The objective of the analysis is to improve our understanding of how satellite-derived soil moisture will impact basin scaled/multi state decision processes linked to emergency planning and preparedness, such as FEMA FloodSMART. Using the snow hydrology model SNOW-17 (NWS) coupled to a large-scale two-dimensional floodplain inundation model LISFLOOD-FP, the study evaluates how different soil moisture states can be captured by satellites to enable a multi-state decision process focused on flood risk and planning. The study develops a scenario that applies historical soil moisture data from past events to monitor basin soil moisture conditions and yields a percent value of the saturation status. Scenario analysis is particularly important for decision makers such as emergency responders and insurers as their operations depend on their ability to gauge and appropriately assess risk. This analysis will enables insurers to develop mitigation strategies and contingency plans for such events.

  16. Radio-Frequency Interference (RFI) Mitigation for the Soil, Moisture Active/Passive (SMAP) Radiometer

    NASA Technical Reports Server (NTRS)

    Bradley, Damon; Brambora, Cliff; Wong, Mark Englin; Miles, Lynn; Durachka, David; Farmer, Brian; Mohammed, Priscilla; Piepmier, Jeff; Medeiros, Jim; Martin Neil; Garcia, Rafael

    2010-01-01

    The presence of anthropogenic RFI is expected to adversely impact soil moisture measurement by NASA s Soil Moisture Active Passive mission. The digital signal processing approach and preliminary design for detecting and mitigating this RFI is presented in this paper. This approach is largely based upon the work of Johnson and Ruf.

  17. The NASA Soil Moisture Active Passive (SMAP) Mission Level 4 Carbon Product calibration and validation using eddy covariance observations across North America, Australia and Finland

    NASA Astrophysics Data System (ADS)

    Stavros, E. N.; Kimball, J. S.; Jones, L. A.; Colliander, A.; Glassy, J. M.; Reichle, R. H.; Schimel, D.; Baldocchi, D. D.; Beringer, J.; Cleverly, J. R.; Desai, A. R.; Euskirchen, E. S.; Hutley, L. B.; Isaac, P. R.; Law, B. E.; Macfarlane, C.; Oechel, W. C.; Prober, S. M.; Jouni, P.; Scott, R. L.; Wheater, H. S.; Zona, D.

    2015-12-01

    The NASA SMAP (Soil Moisture Active Passive) mission was successfully launched January 31st 2015, inaugurating global operational low frequency (L-band) microwave observations of land surface soil moisture and freeze-thaw dynamics with 3-day mean temporal fidelity. The novelty of SMAP is in the high quality of the geophysical observations, global monitoring of dynamic landscape freeze-thaw (FT) and soil moisture (SM) conditions, and the model-enhanced estimation of root zone soil moisture (0-100 cm) and terrestrial carbon fluxes (constrained by environmental controls). The SMAP Level 4 Carbon Product (L4_C) uses lower-level geophysical data to constrain estimates of terrestrial net CO2 exchange and addresses a key science objective of the SMAP mission, which is to understand processes that link the terrestrial water, energy and carbon cycles, particularly in boreal landscapes. Here we present the L4_C calibration and validation infrastructure, which uses eddy covariance tower flux observations. A metric of L4_C product success is to estimate NEE in northern (≥45°N) boreal and arctic biomes to within 30 gCm-2yr-1 or ~1.6 gCm-2 d-1 RMSE, similar to the level of uncertainty for tower observations. We present initial L4_C product comparisons against independent observations from a global network of 33 in situ tower sites, 8 of which are considered primary sites in the high latitudes (≥45°N). Although only primary sites are used to determine product success, all sites are integrated into diagnostic plots to evaluate land cover heterogeneity between local tower footprints and overlying L4_C grid cells, algorithm handling and data quality, thus providing a framework for evaluating environmental constraints on ecosystem productivity and respiration. In addition to mission success, we examine the added value of including FT and SM to constrain terrestrial carbon flux estimates.

  18. An Overview of Production and Validation of the SMAP Passive Soil Moisture Product

    NASA Technical Reports Server (NTRS)

    Chan, S.; O'Neill, P.; Njoku, E.; Jackson, T.; Bindlish, R.

    2015-01-01

    The Soil Moisture Active Passive (SMAP) mission is an L-band mission scheduled for launch in Jan. 2015. The SMAP instruments consist of a radar and a radiometer to obtain complementary information from space for soil moisture and freeze/thaw state research and applications. By utilizing novel designs in antenna construction, retrieval algorithms, and acquisition hardware, SMAP provides a capability for global mapping of soil moisture and freeze/thaw state with unprecedented accuracy, resolution, and coverage. This improvement in hydrosphere state measurement is expected to advance our understanding of the processes that link the terrestrial water, energy and carbon cycles, improve our capability in flood prediction and drought monitoring, and enhance our skills in weather and climate forecast. For swath-based soil moisture measurement, SMAP generates three operational geophysical data products: (1) the radiometer-only soil moisture product (L2_SM_P) posted at 36-kilometer resolution, (2) the radar-only soil moisture product (L2_SM_A) posted at 3-kilometers resolution, and (3) the radar-radiometer combined soil moisture product (L2_SM_AP) posted at 9-kilometers resolution. Each product draws on the strengths of the underlying sensor(s) and plays a unique role in hydroclimatological and hydrometeorological applications. A full suite of SMAP data products is given in Table 1.

  19. The Soil Moisture Active Passive Mission (SMAP) Science Data Products: Results of Testing with Field Experiment and Algorithm Testbed Simulation Environment Data

    NASA Technical Reports Server (NTRS)

    Entekhabi, Dara; Njoku, Eni E.; O'Neill, Peggy E.; Kellogg, Kent H.; Entin, Jared K.

    2010-01-01

    Talk outline 1. Derivation of SMAP basic and applied science requirements from the NRC Earth Science Decadal Survey applications 2. Data products and latencies 3. Algorithm highlights 4. SMAP Algorithm Testbed 5. SMAP Working Groups and community engagement

  20. Technical Report Series on Global Modeling and Data Assimilation. Volume 42; Soil Moisture Active Passive (SMAP) Project Calibration and Validation for the L4_C Beta-Release Data Product

    NASA Technical Reports Server (NTRS)

    Koster, Randal D. (Editor); Kimball, John S.; Jones, Lucas A.; Glassy, Joseph; Stavros, E. Natasha; Madani, Nima (Editor); Reichle, Rolf H.; Jackson, Thomas; Colliander, Andreas

    2015-01-01

    During the post-launch Cal/Val Phase of SMAP there are two objectives for each science product team: 1) calibrate, verify, and improve the performance of the science algorithms, and 2) validate accuracies of the science data products as specified in the L1 science requirements according to the Cal/Val timeline. This report provides analysis and assessment of the SMAP Level 4 Carbon (L4_C) product specifically for the beta release. The beta-release version of the SMAP L4_C algorithms utilizes a terrestrial carbon flux model informed by SMAP soil moisture inputs along with optical remote sensing (e.g. MODIS) vegetation indices and other ancillary biophysical data to estimate global daily NEE and component carbon fluxes, particularly vegetation gross primary production (GPP) and ecosystem respiration (Reco). Other L4_C product elements include surface (<10 cm depth) soil organic carbon (SOC) stocks and associated environmental constraints to these processes, including soil moisture and landscape FT controls on GPP and Reco (Kimball et al. 2012). The L4_C product encapsulates SMAP carbon cycle science objectives by: 1) providing a direct link between terrestrial carbon fluxes and underlying freeze/thaw and soil moisture constraints to these processes, 2) documenting primary connections between terrestrial water, energy and carbon cycles, and 3) improving understanding of terrestrial carbon sink activity in northern ecosystems.

  1. SMAP Launch and Deployment Sequence

    NASA Video Gallery

    This video combines file footage of a Delta II rocket and computer animation to depict the launch and deployment of NASA's Soil Moisture Active Passive satellite. SMAP is scheduled to launch on Nov...

  2. SMAP Science Data System

    NASA Astrophysics Data System (ADS)

    Cuddy, D.; Gluck, S.; Hua, H.; Weiss, B.; Wong, C.; Kwoun, O.; Cruz, J.

    2012-12-01

    NASA's Soil Moisture Active Passive (SMAP) mission will retrieve global surface soil moisture and freeze/thaw state based on measurements acquired by remote sensing instruments that fly on an Earth orbiting satellite. The SMAP observatory will launch no earlier than October 2014 into a near-polar, sun-synchronous orbit. The SMAP instrument suite includes a radiometer and a synthetic aperture radar. This paper will describe the Science Data System (SDS) that will process the SMAP raw data into higher-level products. SMAP data products will provide calibrated radar backscatter and radiometer brightness temperatures, derived geophysical parameters in the form of soil moisture and freeze/thaw states, daily maps of these geophysical parameters, as well as modeled analyses of global soil moisture and carbon flux in Boreal regions. The SDS is a fully automated system that will process the incoming raw data from the instruments, incorporate spacecraft and instrument engineering data, and use both dynamic and static ancillary products from the scientific community. The SDS will use the Object Oriented Data Technology (OODT) from Apache Software Foundation to control the 13 standard data product processors and additional 15 preprocessors. The standard data products will appear in Hierarchical Data Format-5 (HDF5) format. The products will contain metadata that conform to the ISO 19115 standard. The Alaska Satellite Facility (ASF) will host and distribute SMAP Radar data, while the National Snow and Ice Data Center (NSIDC) will host and distribute all other SMAP products.

  3. Multi-Scale Soil Moisture Monitoring and Modeling at ARS Watersheds for NASA's Soil Moisture Active Passive (SMAP) Calibration/Validation Mission

    NASA Astrophysics Data System (ADS)

    Coopersmith, E. J.; Cosh, M. H.

    2014-12-01

    NASA's SMAP satellite, launched in November of 2014, produces estimates of average volumetric soil moisture at 3, 9, and 36-kilometer scales. The calibration and validation process of these estimates requires the generation of an identically-scaled soil moisture product from existing in-situ networks. This can be achieved via the integration of NLDAS precipitation data to perform calibration of models at each ­in-situ gauge. In turn, these models and the gauges' volumetric estimations are used to generate soil moisture estimates at a 500m scale throughout a given test watershed by leveraging, at each location, the gauge-calibrated models deemed most appropriate in terms of proximity, calibration efficacy, soil-textural similarity, and topography. Four ARS watersheds, located in Iowa, Oklahoma, Georgia, and Arizona are employed to demonstrate the utility of this approach. The South Fork watershed in Iowa represents the simplest case - the soil textures and topography are relative constants and the variability of soil moisture is simply tied to the spatial variability of precipitation. The Little Washita watershed in Oklahoma adds soil textural variability (but remains topographically simple), while the Little River watershed in Georgia incorporates topographic classification. Finally, the Walnut Gulch watershed in Arizona adds a dense precipitation network to be employed for even finer-scale modeling estimates. Results suggest RMSE values at or below the 4% volumetric standard adopted for the SMAP mission are attainable over the desired spatial scales via this integration of modeling efforts and existing in-situ networks.

  4. SMAP validation of soil moisture products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil Moisture Active Passive (SMAP) satellite will be launched by the National Aeronautics and Space Administration in October 2014. SMAP will also incorporate a rigorous calibration and validation program that will support algorithm refinement and provide users with information on the accuracy ...

  5. SMAP Science Data System Architecture

    NASA Astrophysics Data System (ADS)

    Cuddy, D.

    2014-12-01

    NASA's Soil Moisture Active Passive (SMAP) mission will retrieve global surface soil moisture and freeze/thaw state based on measurements acquired by remote sensing instruments that fly on an Earth orbiting satellite. The SMAP observatory will launch no earlier than January 8, 2015 into a near-polar, sun-synchronous orbit for a three-year mission. The SMAP instrument suite includes a L-band radiometer and a L-band synthetic aperture radar. This paper will describe the architecture of the Science Data System (SDS) that processes the SMAP raw data into higher-level products. All of the SMAP products appear in the Hierarchical Data Format-5 (HDF5) format. Metadata that conform to the ISO 19115 standard accompany each product. SMAP products range from raw data (Level 0) through parsed and organized telemetry (Level 1A), calibrated signals (Level 1B/1C), retrieved geophysical values (Level 2), daily composite maps (Level 3), to analysis and modeling data (Level 4). This paper will describe an architecture that automates the challenge of delivering multiple products with large data volumes within a few hours to a few days of instrument acquisition. Additional challenges include handling data for a diverse user community as well as rapid data visualization. SMAP faces the additional complexity that the archive and access to the SMAP data processes through two NASA Data Active Archive Centers (DAAC): The Alaska Satellite Facility (ASF) hosts and distributes SMAP Radar data, while the National Snow and Ice Data Center (NSIDC) hosts and distributes all other SMAP products.

  6. Inter-comparison of SMAP, Aquarius and SMOS L-band brightness temperature observations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil Moisture Active Passive (SMAP) mission is scheduled for launch on January 29, 2015. SMAP will make observations with an L-band radar and radiometer using a shared 6 m rotating reflector antenna. SMAP is a fully polarimetric radiometer with the center frequency of 1.41 GHz. The target accuracy o...

  7. Global High Resolution Mapping and Assimilation of Soil Moisture Observations for the SMAP Radar and Radiometer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil Moisture Active and Passive (SMAP) mission is being developed by NASA for launch in 2015. The primary science objectives of SMAP are to enhance understanding of land surface controls on the water, energy and carbon cycles, and to determine their linkages. Moreover, SMAP high-resolution so...

  8. SMAP Science Data Products

    NASA Astrophysics Data System (ADS)

    Cuddy, D.

    2014-12-01

    NASA's Soil Moisture Active Passive (SMAP) mission will retrieve global surface soil moisture and freeze/thaw state based on measurements acquired by remote sensing instruments that fly on an Earth orbiting satellite. The SMAP observatory will launch no earlier than January 8, 2015 into a near-polar, sun-synchronous orbit. The SMAP instrument suite includes a radiometer and synthetic aperture radar. This paper will describe the Science Data System (SDS) that will process the SMAP raw data into higher-level products. SMAP data products will provide calibrated radar backscatter and radiometer brightness temperatures, derived geophysical parameters in the form of soil moisture and freeze/thaw states, daily maps of these geophysical parameters, as well as modeled analyses of global soil moisture and carbon flux in Boreal regions. The SDS is a fully automated system that will process the incoming raw data from the instruments, incorporate spacecraft and instrument engineering data, and use both dynamic and static ancillary products from the scientific community. The SDS will produce 14 standard data product processors. This paper will discuss the standard data products, their format, metadata, quality assessment products, as well as the planned release dates for the products both Beta and Validated quality. The standard data products will appear in Hierarchical Data Format-5 (HDF5) format. The products will contain metadata that conform to the ISO 19115 standard. The Alaska Satellite Facility (ASF) will host and distribute SMAP Radar data, while the National Snow and Ice Data Center (NSIDC) will host and distribute all other SMAP products.

  9. Assessment of Soil Moisture Data Requirements by the Potential SMAP Data User Community: Review of SMAP Mission User Community

    NASA Technical Reports Server (NTRS)

    Brown, Molly E.; Escobar, Vanessa M.

    2013-01-01

    NASA's Soil Moisture Active and Passive (SMAP) mission is planned for launch in October 2014 and will provide global measurements of soil moisture and freeze thaw state. The project is driven by both basic research and applied science goals. Understanding how application driven end-users will apply SMAP data, prior to the satellite's launch, is an important goal of NASA's applied science program and SMAP mission success. Because SMAP data are unique, there are no direct proxy data sets that can be used in research and operational studies to determine how the data will interact with existing processes. The objective of this study is to solicit data requirements, accuracy needs, and current understanding of the SMAP mission from the potential user community. This study showed that the data to be provided by the SMAP mission did substantially meet the user community needs. Although there was a broad distribution of requirements stated, the SMAP mission fit within these requirements.

  10. Technical Report Series on Global Modeling and Data Assimilation. Volume 40; Soil Moisture Active Passive (SMAP) Project Assessment Report for the Beta-Release L4_SM Data Product

    NASA Technical Reports Server (NTRS)

    Koster, Randal D.; Reichle, Rolf H.; De Lannoy, Gabrielle J. M.; Liu, Qing; Colliander, Andreas; Conaty, Austin; Jackson, Thomas; Kimball, John

    2015-01-01

    During the post-launch SMAP calibration and validation (Cal/Val) phase there are two objectives for each science data product team: 1) calibrate, verify, and improve the performance of the science algorithm, and 2) validate the accuracy of the science data product as specified in the science requirements and according to the Cal/Val schedule. This report provides an assessment of the SMAP Level 4 Surface and Root Zone Soil Moisture Passive (L4_SM) product specifically for the product's public beta release scheduled for 30 October 2015. The primary objective of the beta release is to allow users to familiarize themselves with the data product before the validated product becomes available. The beta release also allows users to conduct their own assessment of the data and to provide feedback to the L4_SM science data product team. The assessment of the L4_SM data product includes comparisons of SMAP L4_SM soil moisture estimates with in situ soil moisture observations from core validation sites and sparse networks. The assessment further includes a global evaluation of the internal diagnostics from the ensemble-based data assimilation system that is used to generate the L4_SM product. This evaluation focuses on the statistics of the observation-minus-forecast (O-F) residuals and the analysis increments. Together, the core validation site comparisons and the statistics of the assimilation diagnostics are considered primary validation methodologies for the L4_SM product. Comparisons against in situ measurements from regional-scale sparse networks are considered a secondary validation methodology because such in situ measurements are subject to upscaling errors from the point-scale to the grid cell scale of the data product. Based on the limited set of core validation sites, the assessment presented here meets the criteria established by the Committee on Earth Observing Satellites for Stage 1 validation and supports the beta release of the data. The validation against

  11. Global Evaporation Estimates from SMAP Passive Microwave Soil Moisture Retrievals Using Conditional Sampling.

    NASA Astrophysics Data System (ADS)

    Vreugdenhil, M.; Entekhabi, D.; Konings, A. G.; Salvucci, G.; Hogan, P.

    2015-12-01

    Evaporation links the water, energy and carbon cycles over land yet even its climatology on global scale is not observed. Tower-based flux measurements are sparse and do not cover diverse biomes and climates. In the last decades, many strategies to derive evaporation based on remote sensing measurements have been developed. However, these methods are dependent on a variety of assumptions and auxiliary data, making them more prone to error propagation. A more data-driven method was developed by Salvucci (2001), who found that under statistical stationary conditions the expected change in soil moisture storage is zero when conditioned to a certain storage for a certain time interval. Consequently, using the water balance, precipitation conditionally averaged to the soil moisture storage is equal to the total loss: evaporation and drainage. Using only soil moisture and precipitation data as model inputs reduces the sources of uncertainty. In this presentation we provide the first estimates of global evaporation from NASA's Soil Moisture Active Passive mission by applying the conditional sampling method to passive microwave soil moisture time series and in situ precipitation data. The obtained evaporation estimates show a good correspondence to measured evaporation from eddy correlation towers over selected field sites. Subsequently, a simple approach is developed to directly estimate evaporation from SMAP soil moisture data. This approach enables the investigation of dynamics in evaporation during the dry-down after storms. The timing of the transition between the different stages of evaporation is assessed for different climates especially the transition from stage 1 to stage 2 evaporation; atmosphere limited evaporation to soil limited evaporation respectively. Investigations into the dynamics of unstressed evaporation and transpiration and the transition from stage 1 to stage 2 evaporation increases our understanding of water stress and soil desiccation. It also

  12. Initial validation of the Soil Moisture Active Passive mission using USDA-ARS watersheds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil Moisture Active Passive (SMAP) Mission was launched in January 2015 to measure global surface soil moisture. The calibration and validation program of SMAP relies upon an international cooperative of in situ networks to provide ground truth references across a variety of landscapes. The U...

  13. Generating large-scale estimates from sparse, in-situ networks: multi-scale soil moisture modeling at ARS watersheds for NASA’s soil moisture active passive (SMAP) calibration/validation mission

    Technology Transfer Automated Retrieval System (TEKTRAN)

    NASA’s SMAP satellite, launched in November of 2014, produces estimates of average volumetric soil moisture at 3, 9, and 36-kilometer scales. The calibration and validation process of these estimates requires the generation of an identically-scaled soil moisture product from existing in-situ networ...

  14. SMAP Data Assimilation at the GMAO

    NASA Technical Reports Server (NTRS)

    Reichle, R.; De Lannoy, G.; Liu, Q.; Ardizzone, J.

    2016-01-01

    The NASA Soil Moisture Active Passive (SMAP) mission has been providing L-band (1.4 GHz) passive microwave brightness temperature (Tb) observations since April 2015. These observations are sensitive to surface(0-5 cm) soil moisture. Several of the key applications targeted by SMAP, however, require knowledge of deeper-layer, root zone (0-100 cm) soil moisture, which is not directly measured by SMAP. The NASA Global Modeling and Assimilation Office (GMAO) contributes to SMAP by providing Level 4 data, including the Level 4 Surface and Root Zone Soil Moisture(L4_SM) product, which is based on the assimilation of SMAP Tb observations in the ensemble-based NASA GEOS-5 land surface data assimilation system. The L4_SM product offers global data every three hours at 9 km resolution, thereby interpolating and extrapolating the coarser- scale (40 km) SMAP observations in time and in space (both horizontally and vertically). Since October 31, 2015, beta-version L4_SM data have been available to the public from the National Snow and Ice Data Center for the period March 31, 2015, to near present, with a mean latency of approx. 2.5 days.

  15. SMAP Radar Data and Services at the ASF DAAC

    NASA Astrophysics Data System (ADS)

    Arko, S. A.; Dixon, I. R.; Wolf, V. G.

    2015-12-01

    In January 2015 NASA launched the Soil Moisture Active Passive (SMAP) spacecraft. SMAP's mission was to create high-resolution soil moisture and freeze-thaw products using the combination of an L-band polarimetric synthetic aperture radar (SAR) and an L-band radiometer. Two NASA Distributed Active Archive Centers (DAACs) were tasked with distribution of the SMAP data products. The Alaska Satellite Facility (ASF) DAAC was tasked to archive and distribute the SMAP radar products. In order to best support distribution of SMAP swath radar products and SMAP users, the ASF DAAC enhanced the DAAC data system in a number of ways that will be detailed in this presentation. SMAP radar data are unique for SAR in that they are provided as half-orbit swaths over 1000km wide. This presentation will focus on two primary areas of DAAC support for SMAP. First, the ASF data discovery client, Vertex, has been updated to better support SMAP SAR data. This included enhancements to the user interface to better support swath visualizations as well as increased search capability. Utilizing NASA's Common Metadata Repository (CMR), Vertex will allow users to download both the Level 1 SAR product as well as the higher-level products that it contributed to. In this way, the distributed nature of the data archives is better abstracted from the user experience and users have quick access to a greater variety of data. Beyond enabling data search, ASF DAAC is also supporting data utilization through the development of polar mosaics using the SAR data. SMAP is able to achieve nearly complete coverage of the Arctic north of 55 degrees every 24 hours. Based on the polarimetric SMAP data, Arctic mosaics are generated each day in geotiff format at a fixed grid spacing to allow for easy incorporation to existing workflows. Prototype ice motion products will also be shown that directly demonstrate the utility of these daily mosaics.

  16. The SMAP level 4 surface and root zone soil moisture data assimilation product

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The NASA Soil Moisture Active Passive (SMAP) mission is scheduled for launch in January 2015 and will provide L-band radar and radiometer observations that are sensitive to surface soil moisture (in the top few centimeters of the soil column). For several of the key applications targeted by SMAP, ho...

  17. SMAP Data Assimilation at NASA SPoRT

    NASA Technical Reports Server (NTRS)

    Blankenship, Clay B.; Case, Jonathan L.; Zavodsky, Bradley T.

    2016-01-01

    The NASA Short-Term Prediction Research and Transition (SPoRT) Center maintains a near-real- time run of the Noah Land Surface Model within the Land Information System (LIS) at 3-km resolution. Soil moisture products from this model are used by several NOAA/National Weather Service Weather Forecast Offices for flood and drought situational awareness. We have implemented assimilation of soil moisture retrievals from the Soil Moisture Ocean Salinity (SMOS) and Soil Moisture Active/ Passive (SMAP) satellites, and are now evaluating the SMAP assimilation. The SMAP-enhanced LIS product is planned for public release by October 2016.

  18. SMAP Algorithms & Cal/Val Workshop

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil Moisture Active and Passive (SMAP) mission is one of four Decadal Survey missions recommended by the U.S. National Research Council for launch in the early part of the next decade ("Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond," NRC, Committ...

  19. Validating SMAP L2/3 products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil Moisture Active Passive (SMAP) mission entered its one year calibration and validation (cal/val) phase in May, 2015. This began with a focus on instrument measurements, brightness temperature and backscatter, and has now evolved to the geophysical products that include three different spati...

  20. SMAP Radar Processing and Calibration

    NASA Technical Reports Server (NTRS)

    West, R.; Jaruwatanadilok, S.; Kwoun, O.; Chaubell, M.

    2013-01-01

    The Soil Moisture Active Passive (SMAP) mission is part of the NASA space-based Earth observation program, and consists of an L-band radar and radiometer scheduled for launch into sun synchronous orbit in late 2014. A joint effort of the Jet Propulsion Laboratory (JPL) and the Goddard Space Flight Center (GSFC), the SMAP mission draws heavily on the design and risk reduction heritage of the Hydrosphere State (Hydros) mission [1], [2]. The SMAP science and applications objectives are to: 1) understand processes that link the terrestrial water, energy and carbon cycles, 2) estimate global water and energy fluxes at the land surface, 3) quantify net carbon flux in boreal landscapes, 4) enhance weather and climate forecast skill, and 5) develop improved flood prediction and drought monitoring capability. To meet these science objectives, SMAP ground processing will combine the attributes of the radar and radiometer observations (in terms of their spatial resolution and sensitivity to soil moisture, surface roughness, and vegetation) to estimate soil moisture with 4% volumetric accuracy at a resolution of 10 km, and freeze-thaw state at a resolution of 1-3 km. Model sensitivities translate the soil moisture accuracy to a radar backscatter accuracy of 1 dB (1 sigma) at 3 km resolution and a brightness temperature accuracy of 1.3 K at 40 km resolution. This paper will describe the level 1 radar processing and calibration challenges and the choices made so far for the algorithms and software implementation.

  1. SMAP Mission Applications; Post Launch Research and the Early Adopter Program Socioeconomic Impact Analyses

    NASA Astrophysics Data System (ADS)

    Escobar, V. M.

    2015-12-01

    NASA's Soil Moisture Active Passive (SMAP) Mission, launched January 31, 2015, has grown an Early Adopter (EA) community since 2010. Over the next two years, the mission Applications Team will conduct socioeconomic impact analyses on thematic EA research in an effort to demonstrate the value of SMAP products in societally relevant, decision support applications. The SMAP mission provides global observations of the Earth's surface soil moisture, providing high accuracy, resolution and continuous global coverage. The SMAP Applications Team will document and evaluate the use of SMAP science products in applications related to weather forecasting, drought, agriculture productivity, floods, human health and national security. SMAP EA research in applied science cases such as sea ice and sea surface winds will also be evaluated. SMAP EAs provide a thematically scaled perspective on the use and impact of SMAP data. This analysis will demonstrate how the investments in pre-launch applications and early adopter efforts contributed to the mission value, product impact and fueled new research that contributes to the use of mission products, thereby enhancing mission success. This paper presents a set of Early Adopter case studies that show how EAs plan to use SMAP science products to enhance decision support systems, and about how the SMAP data stream affects these users. Detailed tracking of this comprehensive set of case studies will enable quantification and monetization of the benefits of an application by the end of the first two years after launch.

  2. Soil Moisture Active Passive Satellite Status and Recent Validation Results

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil Moisture Active Passive (SMAP) mission was launched in January, 2015 and began its calibration and validation (cal/val) phase in May, 2015. Cal/Val will begin with a focus on instrument measurements, brightness temperature and backscatter, and evolve to the geophysical products that include...

  3. Soil Moisture Active Passive Validation Experiment 2008 (SMAPVEX08)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil Moisture Active Passive Mission (SMAP) is currently addressing issues related to the development and selection of soil moisture retrieval algorithms. Several forums have identified a number of specific questions that require supporting field experiments. Addressing these issues as soon as p...

  4. SMAPVEX08: Soil Moisture Active Passive Validation Experiment 2008

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil Moisture Active Passive Mission (SMAP) is currently addressing issues related to the development and selection of retrieval algorithms as well as refining the mission design and instruments. Some of these issues require resolution as soon as possible. Several forums had identified specific ...

  5. Evaluation of SMAP Level 2 Soil Moisture Algorithms Using SMOS Data

    NASA Technical Reports Server (NTRS)

    Bindlish, Rajat; Jackson, Thomas J.; Zhao, Tianjie; Cosh, Michael; Chan, Steven; O'Neill, Peggy; Njoku, Eni; Colliander, Andreas; Kerr, Yann; Shi, J. C.

    2011-01-01

    The objectives of the SMAP (Soil Moisture Active Passive) mission are global measurements of soil moisture and land freeze/thaw state at 10 km and 3 km resolution, respectively. SMAP will provide soil moisture with a spatial resolution of 10 km with a 3-day revisit time at an accuracy of 0.04 m3/m3 [1]. In this paper we contribute to the development of the Level 2 soil moisture algorithm that is based on passive microwave observations by exploiting Soil Moisture Ocean Salinity (SMOS) satellite observations and products. SMOS brightness temperatures provide a global real-world, rather than simulated, test input for the SMAP radiometer-only soil moisture algorithm. Output of the potential SMAP algorithms will be compared to both in situ measurements and SMOS soil moisture products. The investigation will result in enhanced SMAP pre-launch algorithms for soil moisture.

  6. Using SMOS obervations for science development of the SMAP level 4 surface and root zone soil moisture algorithm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The NASA Soil Moisture Active and Passive (SMAP) mission is targeted for launch in October 2014. The soil moisture mapping provided by SMAP has practical applications in weather and seasonal climate prediction, agriculture, human health, drought and flood decision support. The Soil Moisture and Oc...

  7. SMAP Verification and Validation Project - Final Report

    NASA Technical Reports Server (NTRS)

    Murry, Michael

    2012-01-01

    In 2007, the National Research Council (NRC) released the Decadal Survey of Earth science. In the future decade, the survey identified 15 new space missions of significant scientific and application value for the National Aeronautics and Space Administration (NASA) to undertake. One of these missions was the Soil Moisture Active Passive (SMAP) mission that NASA assigned to the Jet Propulsion Laboratory (JPL) in 2008. The goal of SMAP1 is to provide global, high resolution mapping of soil moisture and its freeze/thaw states. The SMAP project recently passed its Critical Design Review and is proceeding with its fabrication and testing phase.Verification and Validation (V&V) is widely recognized as a critical component in system engineering and is vital to the success of any space mission. V&V is a process that is used to check that a system meets its design requirements and specifications in order to fulfill its intended purpose. Verification often refers to the question "Have we built the system right?" whereas Validation asks "Have we built the right system?" Currently the SMAP V&V team is verifying design requirements through inspection, demonstration, analysis, or testing. An example of the SMAP V&V process is the verification of the antenna pointing accuracy with mathematical models since it is not possible to provide the appropriate micro-gravity environment for testing the antenna on Earth before launch.

  8. Early results of the Soil Moisture Active Passive Validation Experiment (SMAPVEX15)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In August of 2015, the Soil Moisture Active Passive Validation Experiment (SMAPVEX15) was conducted to provide a high resolution soil moisture dataset for the calibration/validation of the Soil Moisture Active Passive Mission (SMAP). The Upper San Pedro River Basin and the USDA-ARS Walnut Gulch LTAR...

  9. SMAP RADAR Processing and Calibration

    NASA Astrophysics Data System (ADS)

    West, R. D.; Jaruwatanadilok, S.; Kwoun, O.; Chaubell, M. J.

    2013-12-01

    The Soil Moisture Active Passive (SMAP) mission uses L-band radar and radiometer measurements to estimate soil moisture with 4% volumetric accuracy at a resolution of 10 km, and freeze-thaw state at a resolution of 1-3 km. Model sensitivities translate the soil moisture accuracy to a radar backscatter accuracy of 1 dB at 3 km resolution and a brightness temperature accuracy of 1.3 K at 40 km resolution. This presentation will describe the level 1 radar processing and calibration challenges and the choices made so far for the algorithms and software implementation. To obtain the desired high spatial resolution the level 1 radar ground processor employs synthetic aperture radar (SAR) imaging techniques. Part of the challenge of the SMAP data processing comes from doing SAR imaging on a conically scanned system with rapidly varying squint angles. The radar echo energy will be divided into range/Doppler bins using time domain processing algorithms that can easily follow the varying squint angle. For SMAP, projected range resolution is about 250 meters, while azimuth resolution varies from 400 meters to 1.2 km. Radiometric calibration of the SMAP radar means measuring, characterizing, and where necessary correcting the gain and noise contributions from every part of the system from the antenna radiation pattern all the way to the ground processing algorithms. The SMAP antenna pattern will be computed using an accurate antenna model, and then validated post-launch using homogeneous external targets such as the Amazon rain forest to look for uncorrected gain variation. Noise subtraction is applied after image processing using measurements from a noise only channel. Variations of the internal electronics are tracked by a loopback measurement which will capture most of the time and temperature variations of the transmit power and receiver gain. Long-term variations of system performance due to component aging will be tracked and corrected using stable external reference

  10. SMAP Instrument Mechanical System Engineering

    NASA Technical Reports Server (NTRS)

    Slimko, Eric; French, Richard; Riggs, Benjamin

    2013-01-01

    The Soil Moisture Active Passive (SMAP) mission, scheduled for launch by the end of 2014, is being developed to measure the soil moisture and soil freeze/thaw state on a global scale over a three-year period. The accuracy, resolution, and global coverage of SMAP measurements are invaluable across many science and applications disciplines including hydrology, climate, carbon cycle, and the meteorological, environment, and ecology applications communities. The SMAP observatory is composed of a despun bus and a spinning instrument platform that includes both a deployable 6 meter aperture low structural frequency Astromesh reflector and a spin control system. The instrument section has engendered challenging mechanical system issues associated with the antenna deployment, flexible antenna pointing in the context of a multitude of disturbances, spun section mass properties, spin control system development, and overall integration with the flight system on both mechanical and control system levels. Moreover, the multitude of organizations involved, including two major vendors providing the spin subsystem and reflector boom assembly plus the flight system mechanical and guidance, navigation, and control teams, has led to several unique system engineering challenges. Capturing the key physics associated with the function of the flight system has been challenging due to the many different domains that are applicable. Key interfaces and operational concepts have led to complex negotiations because of the large number of organizations that integrate with the instrument mechanical system. Additionally, the verification and validation concerns associated with the mechanical system have had required far-reaching involvement from both the flight system and other subsystems. The SMAP instrument mechanical systems engineering issues and their solutions are described in this paper.

  11. The SMAP Dictionary Management System

    NASA Technical Reports Server (NTRS)

    Smith, Kevin A.; Swan, Christoper A.

    2014-01-01

    The Soil Moisture Active Passive (SMAP) Dictionary Management System is a web-based tool to develop and store a mission dictionary. A mission dictionary defines the interface between a ground system and a spacecraft. In recent years, mission dictionaries have grown in size and scope, making it difficult for engineers across multiple disciplines to coordinate the dictionary development effort. The Dictionary Management Systemaddresses these issues by placing all dictionary information in one place, taking advantage of the efficiencies inherent in co-locating what were once disparate dictionary development efforts.

  12. SMOS/SMAP Synergy for SMAP Level 2 Soil Moisture Algorithm Evaluation

    NASA Technical Reports Server (NTRS)

    Bindlish, Rajat; Jackson, Thomas J.; Zhao, Tianjie; Cosh, Michael; Chan, Steven; O'Neill, Peggy; Njoku, Eni; Colliander, Andreas; Kerr, Yann

    2011-01-01

    Soil Moisture Active Passive (SMAP) satellite has been proposed to provide global measurements of soil moisture and land freeze/thaw state at 10 km and 3 km resolutions, respectively. SMAP would also provide a radiometer-only soil moisture product at 40-km spatial resolution. This product and the supporting brightness temperature observations are common to both SMAP and European Space Agency's Soil Moisture and Ocean Salinity (SMOS) mission. As a result, there are opportunities for synergies between the two missions. These include exploiting the data for calibration and validation and establishing longer term L-band brightness temperature and derived soil moisture products. In this investigation we will be using SMOS brightness temperature, ancillary data, and soil moisture products to develop and evaluate a candidate SMAP L2 passive soil moisture retrieval algorithm. This work will begin with evaluations based on the SMOS product grids and ancillary data sets and transition to those that will be used by SMAP. An important step in this analysis is reprocessing the multiple incidence angle observations provided by SMOS to a global brightness temperature product that simulates the constant 40 degree incidence angle observations that SMAP will provide. The reprocessed brightness temperature data provide a basis for evaluating different SMAP algorithm alternatives. Several algorithms are being considered for the SMAP radiometer-only soil moisture retrieval. In this first phase, we utilized only the Single Channel Algorithm (SCA), which is based on the radiative transfer equation and uses the channel that is most sensitive to soil moisture (H-pol). Brightness temperature is corrected sequentially for the effects of temperature, vegetation, roughness (dynamic ancillary data sets) and soil texture (static ancillary data set). European Centre for Medium-Range Weather Forecasts (ECMWF) estimates of soil temperature for the top layer (as provided as part of the SMOS

  13. SMAP Validation and Accuracy Assessment of Soil Moisture Products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: The Soil Moisture Active Passive (SMAP) mission was launched in January, 2015 and will begin its calibration and validation (Cal/Val) phase in May, 2015. This will begin with a focus on instrument measurements, brightness temperature and backscatter, and evolve to the geophysical produ...

  14. The SMAP Level 4 surface and root-zone soil moisture product

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Slated for launch in 2015, the NASA Soil Moisture Active/Passive mission represents a generational advance in our ability to globally observe time and space variations in surface soil moisture fields. The SMAP mission concept is based on the integrated use of L-band active radar and passive radiome...

  15. Retrieval of Sea Surface Salinity and Wind from The NASA Soil Moisture Active Passive Mission Data

    NASA Astrophysics Data System (ADS)

    Yueh, S. H.; Fore, A.; Tang, W.; Hayashi, A.

    2015-12-01

    NASA's Soil Moisture Active Passive (SMAP) mission, the first Earth Science Decadal Survey mission, was launched January 31, 2015 to provide high-resolution, frequent-revisit global mapping of soil moisture. SMAP has two instruments, a polarimetric radiometer and a multi-polarization synthetic aperture radar. Both instruments operate at L-band frequencies (~ 1GHz) and share a single 6-m rotating mesh antenna, producing a fixed incidence angle conical scan at 40⁰ across a 1000-km swath and a 2-3 day global revisit. The SMAP SSS and ocean surface wind retrieval algorithm developed at the Jet Propulsion Laboratory leverages the QuikSCAT and Aquarius algorithms to account for the two-look geometry (fore and aft looks from the conical scan) and dual-polarization observations for simultaneous retrieval of SSS and wind speed. The retrieval algorithm has been applied to more than three months of SMAP radiometer data. Comparison with the European Center for Medium-Range Weather Forecasting (ECMWF) wind speed suggests that the SMAP wind speed reaches an accuracy of about 0.7 ms-1. The preliminary assessment of the SMAP SSS products gridded at 50 km spatial resolution and weekly intervals is promising. The spatial patterns of the SSS agree well with climatological distributions, but exhibit several unique spatial and temporal features. The temporal evolutions of freshwater plumes from several major rivers, such as the Amazon, Niger, Congo, Ganges, and Mississippi, are all consistent with the timing of rainy and dry seasons, indicated in the SMAP's soil moisture products. Rigorous accuracy assessment will be performed by comparison with in situ SSS data from buoys and ARGO floats. The SMAP evaluation products will be released to the public prior to November 2015.

  16. Automating the SMAP Ground Data System to Support Lights-Out Operations

    NASA Technical Reports Server (NTRS)

    Sanders, Antonio

    2014-01-01

    The Soil Moisture Active Passive (SMAP) Mission is a first tier mission in NASA's Earth Science Decadal Survey. SMAP will provide a global mapping of soil moisture and its freeze/thaw states. This mapping will be used to enhance the understanding of processes that link the terrestrial water, energy, and carbon cycles, and to enhance weather and forecast capabilities. NASA's Jet Propulsion Laboratory has been selected as the lead center for the development and operation of SMAP. The Jet Propulsion Laboratory (JPL) has an extensive history of successful deep space exploration. JPL missions have typically been large scale Class A missions with significant budget and staffing. SMAP represents a new area of JPL focus towards low cost Earth science missions. Success in this new area requires changes to the way that JPL has traditionally provided the Mission Operations System (MOS)/Ground Data System (GDS) functions. The operation of SMAP requires more routine operations activities and support for higher data rates and data volumes than have been achieved in the past. These activities must be addressed by a reduced operations team and support staff. To meet this challenge, the SMAP ground data system provides automation that will perform unattended operations, including automated commanding of the SMAP spacecraft.

  17. Validation of the Soil Moisture Active Passive mission using USDA-ARS experimental watersheds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The calibration and validation program of the Soil Moisture Active Passive mission (SMAP) relies upon an international cooperative of in situ networks to provide ground truth references across a variety of landscapes. The USDA Agricultural Research Service operates several experimental watersheds wh...

  18. Evaluation of the SMAP radiometer lever 2 pre-launch soil moisture algorithms using SMOS data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objectives of the upcoming SMAP (Soil Moisture Active Passive) satellite mission include global measurements of soil moisture at 40 km, 10 km and 3 km resolutions with a 3-day revisit time at an accuracy of 0.04 m3/m3. The 40 km resolution soil moisture product is based primarily on the passiv...

  19. Callibration and validation of SMAP soil moisture and coordination with other satelitte products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil Moisture Active Passive (SMAP) satellite will launch in November 2014 and will provide a suite of soil moisture products at three spatial resolutions (3, 9 and 36 km). The coarsest resolution product is based only on the passive microwave observations and the algorithm being utilized has he...

  20. Validating SMAP L2/3 Products

    NASA Astrophysics Data System (ADS)

    Jackson, T. J.; Colliander, A.; Bindlish, R.; Chan, S.; Das, N. N.; Entekhabi, D.; Kim, S.; Chen, F.; Crow, W. T.; Burgin, M. S.; Asanuma, J.; Berg, A. A.; Cosh, M. H.; Caldwell, T. G.; Martínez-Fernández, J.; Pacheco, A. M.; Su, Z.; Thibeault, M.; Walker, J. P.; Njoku, E. G.; Yueh, S. H.; O'Neill, P. E.

    2015-12-01

    The Soil Moisture Active Passive (SMAP) mission entered its one year calibration and validation (cal/val) phase in May, 2015. This began with a focus on instrument measurements, brightness temperature and backscatter, and has now evolved to the geophysical products that include three different spatial resolutions of Level 2/3 surface soil moisture (36, 9, and 3 km) and freeze-thaw state. The goal is to provide validated products by May, 2016. SMAP utilizes five methodologies in soil moisture cal/val: core validation sites, sparse networks of in situ sensors, inter-comparisons with products from other satellite programs, inter-comparisons with model-based products, and field campaigns. Each methodology has a role in the process. Examples of each methodology will be presented including recent field campaigns. The evaluation of the beta version will the explained and plans for the providing the validated products presented.

  1. Utilization of Ancillary Data Sets for SMAP Algorithm Development and Product Generation

    NASA Technical Reports Server (NTRS)

    ONeill, P.; Podest, E.; Njoku, E.

    2011-01-01

    Algorithms being developed for the Soil Moisture Active Passive (SMAP) mission require a variety of both static and ancillary data. The selection of the most appropriate source for each ancillary data parameter is driven by a number of considerations, including accuracy, latency, availability, and consistency across all SMAP products and with SMOS (Soil Moisture Ocean Salinity). It is anticipated that initial selection of all ancillary datasets, which are needed for ongoing algorithm development activities on the SMAP algorithm testbed at JPL, will be completed within the year. These datasets will be updated as new or improved sources become available, and all selections and changes will be documented for the benefit of the user community. Wise choices in ancillary data will help to enable SMAP to provide new global measurements of soil moisture and freeze/thaw state at the targeted accuracy necessary to tackle hydrologically-relevant societal issues.

  2. An initial assessment of SMAP soil moisture retrievals using high-resolution model simulations and in situ observations

    NASA Astrophysics Data System (ADS)

    Pan, Ming; Cai, Xitian; Chaney, Nathaniel W.; Entekhabi, Dara; Wood, Eric F.

    2016-09-01

    At the end of its first year of operation, we compare soil moisture retrievals from the Soil Moisture Active Passive (SMAP) mission to simulations from a land surface model with meteorological forcing downscaled from observations/reanalysis and in situ observations from sparse monitoring networks within continental United States (CONUS). The radar failure limits the duration of comparisons for the active and combined products (~3 months). Nevertheless, the passive product compares very well against in situ observations over CONUS. On average, SMAP compares to the in situ data even better than the land surface model and provides significant added value on top of the model and thus good potential for data assimilation. At large scale, SMAP is in good agreement with the model in most of CONUS with less-than-expected degradation over mountainous areas. Lower correlation between SMAP and the model is seen in the forested east CONUS and significantly lower over the Canadian boreal forests.

  3. Assimilation of Smos Observations to Generate a Prototype SMAP Level 4 Surface and Root-Zone Soil Moisture Product

    NASA Technical Reports Server (NTRS)

    Reichle, Rolf H.; De Lannoy, Gabrielle J. M.; Crow, Wade T.; Koster, Randal D.; Kimball, John

    2012-01-01

    The Soil Moisture Active and Passive (SMAP; [1]) mission is being implemented by NASA for launch in October 2014. The primary science objectives of SMAP are to enhance understanding of land surface controls on the water, energy and carbon cycles, and to determine their linkages. Moreover, the high-resolution soil moisture mapping provided by SMAP has practical applications in weather and seasonal climate prediction, agriculture, human health, drought and flood decision support. The Soil Moisture and Ocean Salinity (SMOS; [2]) mission was launched by ESA in November 2009 and has since been observing L-band (1.4 GHz) upwelling passive microwaves. In this paper we describe our use of SMOS brightness temperature observations to generate a prototype of the planned SMAP Level 4 Surface and Root-zone Soil Moisture (L4_SM) product [5].

  4. Spatiotemporal analysis of soil moisture in using active and passive remotely sensed data and ground observations

    NASA Astrophysics Data System (ADS)

    Li, H.; Fang, B.; Lakshmi, V.

    2015-12-01

    Abstract: Soil moisture plays a vital role in ecosystem, biological processes, climate, weather and agriculture. The Soil Moisture Active Passive (SMAP) improves data by combining the advantages and avoiding the limitation of passive microwave remote sensing (low resolution), and active microwave (challenge of soil moisture retrieval). This study will advance the knowledge of the application of soil moisture by using the Soil Moisture Active Passive Validation Experiment 2012 (SMAPVEX12) data as well as data collected at Walnut Gulch Arizona in August 2015 during SMAPVEX15. Specifically, we will analyze the 5m radar data from Unmanned Airborne Vehicle Synthetic Aperture Radar (UAVSAR) to study spatial variability within the PALS radiometer pixel. SMAPVEX12/15 and SMAP data will also be analyzed to evaluate disaggregation algorithms. The analytical findings will provide valuable information for policy-makers to initiate and adjust protocols and regulations for protecting land resources and improving environmental conditions. Keywords: soil moisture, Remote Sensing (RS), spatial statistic

  5. Early results of the Soil Moisture Active Passive Validation Experiment (SMAPVEX15)

    NASA Astrophysics Data System (ADS)

    Cosh, M. H.; Jackson, T. J.; Colliander, A.; Goodrich, D. C.; Holifield Collins, C.; McKee, L.; Kim, S.; Yueh, S. H.

    2015-12-01

    In August of 2015, the Soil Moisture Active Passive Validation Experiment (SMAPVEX15) was conducted to provide a high resolution soil moisture dataset for the calibration/validation of the Soil Moisture Active Passive Mission (SMAP). The Upper San Pedro River Basin and the USDA-ARS Walnut Gulch LTAR Watershed provides the infrastructure for the experiment with its extensive soil moisture and soil temperature network. A total of seven aircraft flights are planned for the Passive Active L-Band Scanning instrument (PALS) to provide a high resolution soil moisture map for a variety of soil moisture conditions across the domain. Extensive surface roughness, vegetation and soil rock fraction mapping was conducted to provide a ground truth estimate of the many ancillary datasets used in the SMAP soil moisture algorithms. A review of the methodologies employed in the experiment, as well as initial findings will be discussed.

  6. Seasonal Parameterizations of the Tau-Omega Model Using the ComRAD Ground-Based SMAP Simulator

    NASA Technical Reports Server (NTRS)

    O'Neill, P.; Joseph, A.; Srivastava, P.; Cosh, M.; Lang, R.

    2014-01-01

    NASA's Soil Moisture Active Passive (SMAP) mission is scheduled for launch in November 2014. In the prelaunch time frame, the SMAP team has focused on improving retrieval algorithms for the various SMAP baseline data products. The SMAP passive-only soil moisture product depends on accurate parameterization of the tau-omega model to achieve the required accuracy in soil moisture retrieval. During a field experiment (APEX12) conducted in the summer of 2012 under dry conditions in Maryland, the Combined Radar/Radiometer (ComRAD) truck-based SMAP simulator collected active/passive microwave time series data at the SMAP incident angle of 40 degrees over corn and soybeans throughout the crop growth cycle. A similar experiment was conducted only over corn in 2002 under normal moist conditions. Data from these two experiments will be analyzed and compared to evaluate how changes in vegetation conditions throughout the growing season in both a drought and normal year can affect parameterizations in the tau-omega model for more accurate soil moisture retrieval.

  7. A synergisitic Neural Network Soil Moisture Retrieval Algorithm for SMAP

    NASA Astrophysics Data System (ADS)

    Kolassa, J.; Reichle, R. H.; Gentine, P.; Prigent, C.; Aires, F.; Fang, B.

    2015-12-01

    A Neural Network (NN)-based algorithm is developed to retrieve surface soil moisture from Soil Moisture Active/Passive (SMAP) microwave observations. This statistical approach serves as an alternative to the official Radiative Transfer (RT) based SMAP retrieval algorithm, since it avoids an explicit formulation of the RT processes as well as the use of often uncertain or unavailable a priori knowledge for additional surface parameters. The NN algorithm is calibrated on observations from the SMAP radiometer and radar as well as surface soil moisture fields from the MERRA-2 reanalysis. To highlight different physical aspects of the satellite signals and to maximize the soil moisture information, different preprocessing techniques of the SMAP data are investigated. These include an analysis of radiometer polarization and diurnal indices to isolate the surface temperature contribution, as well as the radar co- and cross-polarized channels to account for vegetation effects. A major difference with respect to the official retrieval is the increased importance given to the information provided by the SMAP radar or other active sensors, utilizing not only the relative spatial structures, but also the absolute soil moisture information provided. The NN methodology combines multiple sensor observations in a data fusion approach and is thus able to fully exploit the complementarity of the information provided by the different instruments. The algorithm is used to compute global estimates of surface soil moisture and evaluated against retrieved soil moisture from SMOS as well as in situ observations from the International Soil Moisture Network (ISMN). The calibration on MERRA-2 data means that the NN retrieval algorithm functions as the model operator in a data assimilation framework yielding soil moisture estimates that are very compatible with the model. This could facilitate the assimilation of SMAP observations into land surface and numerical weather prediction models.

  8. Experimental High Resolution (3 km) SMAP Soil Moisture Data Fields With Uncertainty Estimates

    NASA Astrophysics Data System (ADS)

    Das, N. N.

    2015-12-01

    NASA's Soil Moisture Active Passive (SMAP) mission was launched on January 31st, 2015. The objective of the mission is global mapping of surface soil moisture and landscape freeze/thaw state. SMAP utilizes an L-band radar and radiometer sharing a rotating 6-meter mesh reflector antenna. The SMAP spacecraft is in a 685-km Sun-synchronous near-polar orbit, and viewing the surface at a constant 40-degree incidence angle with a 1000-km swath width. Merging of the high-resolution active (radar) and coarse-resolution but high-sensitivity passive (radiometer) L-band observations enable an unprecedented combination of accuracy, resolution, coverage and revisit-time for soil moisture and freeze/thaw state retrievals. However, on July 7th, 2015, the SMAP radar encountered an anomaly and is currently inoperable. Efforts are being made to revive the SMAP radar. Due to the present status of the SMAP observatory, nearly ~2.5 months (from the end of In-Orbit-Check April 13th, 2015 to July 7th, 2015) of the SMAP Active Passive product will be available to public through the NASA DAAC at National Snow and Ice Data Center (NSIDC). The baseline L2_SM_AP product is retrieved soil moisture from the disaggregated/downscaled brightness temperature obtained by merging the coarse-resolution (~36 km) radiometer brightness temperature data and the high-resolution (~3 km) radar backscatter data. The baseline product is intermediate scale 9 km global soil moisture information. Experimentally, a much higher resolution global surface soil moisture data set is also produced at 3 km. This experimental product covering the 2.5 Spring/Summer months is the focus of this presentation. We specifically focus on the analysis of errors and reliability of this data set. The errors in disaggregated brightness temperatures and the retrived soil moisture estimates are discussed. In the presentation the accuracies of the SMAP L2-SM_AP soil moisture retrievals will be shown using summary comparisons with in

  9. The Use of Modeling for Flight Software Engineering on SMAP

    NASA Technical Reports Server (NTRS)

    Murray, Alexander; Jones, Chris G.; Reder, Leonard; Cheng, Shang-Wen

    2011-01-01

    The Soil Moisture Active Passive (SMAP) mission proposes to deploy an Earth-orbiting satellite with the goal of obtaining global maps of soil moisture content at regular intervals. Launch is currently planned in 2014. The spacecraft bus would be built at the Jet Propulsion Laboratory (JPL), incorporating both new avionics as well as hardware and software heritage from other JPL projects. [4] provides a comprehensive overview of the proposed mission

  10. Near-Real-Time, Global Radar Data at the Alaska Satellite Facility DAAC from NASA's SMAP Satellite

    NASA Astrophysics Data System (ADS)

    Arko, S. A.; Allen, A. R.; Dixon, I. R.

    2014-12-01

    The Alaska Satellite Facility (ASF) Distributed Active Archive Center (DAAC) is supporting NASA's SMAP (Soil Moisture Active Passive) satellite mission, which launches in January 2015. SMAP will measure global soil moisture and its freeze-thaw state every 3 days using an L-band synthetic aperture radar (SAR) and radiometer. ASF, along with the National Snow and Ice Data Center DAAC and NASA's Earth Science Data and Information System (ESDIS), is identifying and developing tools and technologies to facilitate use of global, near-real-time data by the SMAP user community. ASF will host the SMAP Level 1 radar data and make them available for download through ASF's data discovery interface, Vertex, and the ASF Application Programming Interface. Vertex allows a user to search, visualize and download SAR data, browse images and relevant metadata, and will offer the complete SMAP L1 radar archive to the public. The entire SMAP archive consisting of level 1-4 data can be accessed via Reverb, the NASA EOSDIS metadata and service discovery tool. In anticipation of the SMAP launch and data release, ASF has developed and released a new website (https://www.asf.alaska.edu/smap/) and a suite of web resources, including interactive media, technical information, a product guide, related publications, and tools for working with the HDF5 data format. The ASF SMAP team is exploring OPeNDAP and the Jet Propulsion Laboratory's Webification technologies for enhancing in-browser data visualization and analysis. These technologies, and tools developed with them, represent opportunities for exposing this valuable dataset to areas with limited bandwidth or understanding of radar data. This presentation will highlight the enabling technologies and techniques ASF is employing to bring these data to new scientific and applications users and respond to ever-changing user needs.

  11. SMAP RADAR Calibration and Validation

    NASA Astrophysics Data System (ADS)

    West, R. D.; Jaruwatanadilok, S.; Chaubel, M. J.; Spencer, M.; Chan, S. F.; Chen, C. W.; Fore, A.

    2015-12-01

    The Soil Moisture Active Passive (SMAP) mission launched on Jan 31, 2015. The mission employs L-band radar and radiometer measurements to estimate soil moisture with 4% volumetric accuracy at a resolution of 10 km, and freeze-thaw state at a resolution of 1-3 km. Immediately following launch, there was a three month instrument checkout period, followed by six months of level 1 (L1) calibration and validation. In this presentation, we will discuss the calibration and validation activities and results for the L1 radar data. Early SMAP radar data were used to check commanded timing parameters, and to work out issues in the low- and high-resolution radar processors. From April 3-13 the radar collected receive only mode data to conduct a survey of RFI sources. Analysis of the RFI environment led to a preferred operating frequency. The RFI survey data were also used to validate noise subtraction and scaling operations in the radar processors. Normal radar operations resumed on April 13. All radar data were examined closely for image quality and calibration issues which led to improvements in the radar data products for the beta release at the end of July. Radar data were used to determine and correct for small biases in the reported spacecraft attitude. Geo-location was validated against coastline positions and the known positions of corner reflectors. Residual errors at the time of the beta release are about 350 m. Intra-swath biases in the high-resolution backscatter images are reduced to less than 0.3 dB for all polarizations. Radiometric cross-calibration with Aquarius was performed using areas of the Amazon rain forest. Cross-calibration was also examined using ocean data from the low-resolution processor and comparing with the Aquarius wind model function. Using all a-priori calibration constants provided good results with co-polarized measurements matching to better than 1 dB, and cross-polarized measurements matching to about 1 dB in the beta release. During the

  12. Evaluation of the validated soil moisture product from the SMAP radiometer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study, we used a multilinear regression approach to retrieve surface soil moisture from NASA’s Soil Moisture Active Passive (SMAP) satellite data to create a global dataset of surface soil moisture which is consistent with ESA’s Soil Moisture and Ocean Salinity (SMOS) satellite retrieved sur...

  13. SMAP L2/L3 Soil moisture product validation with core validation sites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil Moisture Active Passive (SMAP) mission was launched by NASA in January, 2015 and entered its one year calibration and validation (cal/val) phase in May, 2015. This began with a focus on instrument measurements, brightness temperature and backscatter, and has now evolved to the geophysical p...

  14. Data Assimilation of SMAP Observations and the Impact on Weather Forecasts and Heat Stress

    NASA Technical Reports Server (NTRS)

    Zavodsky, Bradley; Case, Jonathan; Blankenship, Clay; Crosson, William; White, Khristopher

    2014-01-01

    SPoRT produces real-time LIS soil moisture products for situational awareness and local numerical weather prediction over CONUS, Mesoamerica, and East Africa ?Currently interact/collaborate with operational partners on evaluation of soil moisture products ?Drought/fire ?Extreme heat ?Convective initiation ?Flood and water borne diseases ?Initial efforts to assimilate L2 soil moisture observations from SMOS (as a precursor for SMAP) have been successful ?Active/passive blended product from SMAP will be assimilated similarly and higher spatial resolution should improve on local-scale processes

  15. Development of the Large Aperture Reflector/Boom Assembly for the SMAP Spacecraft

    NASA Technical Reports Server (NTRS)

    Mobrem, Mehran; Keay, Edward; Marks, Geoff; Slimko, Eric

    2012-01-01

    The Jet Propulsion Laboratory's (JPL) Soil Moisture Active/Passive (SMAP) mission is to measure and monitor global soil moisture dynamics and freeze/thaw states. The rotating Reflector and Boom Assembly (RBA) on SMAP presents significant design and development challenges. The payload configuration utilizes a common Radiometer and Radar feedhorn and a 6-meter deployable mesh reflector all spinning at 14.6 rpm. The evolution of the RBA system solution, development of the mass properties management approach and RBA dynamics are discussed.

  16. SMAP Validation Experiment 2015 (SMAPVEX15)

    NASA Astrophysics Data System (ADS)

    Colliander, A.; Jackson, T. J.; Cosh, M. H.; Misra, S.; Crow, W. T.; Chae, C. S.; Moghaddam, M.; O'Neill, P. E.; Entekhabi, D.; Yueh, S. H.

    2015-12-01

    NASA's (National Aeronautics and Space Administration) Soil Moisture Active Passive (SMAP) mission was launched in January 2015. The objective of the mission is global mapping of soil moisture and freeze/thaw state. For soil moisture algorithm validation, the SMAP project and NASA coordinated SMAPVEX15 around the Walnut Gulch Experimental Watershed (WGEW) in Tombstone, Arizona on August 1-19, 2015. The main goals of SMAPVEX15 are to understand the effects and contribution of heterogeneity on the soil moisture retrievals, evaluate the impact of known RFI sources on retrieval, and analyze the brightness temperature product calibration and heterogeneity effects. Additionally, the campaign aims to contribute to the validation of GPM (Global Precipitation Mission) data products. The campaign will feature three airborne microwave instruments: PALS (Passive Active L-band System), UAVSAR (Uninhabited Aerial Vehicle Synthetic Aperture Radar) and AirMOSS (Airborne Microwave Observatory of Subcanopy and Subsurface). PALS has L-band radiometer and radar, and UAVSAR and AirMOSS have L- and P-band synthetic aperture radars, respectively. The PALS instrument will map the area on seven days coincident with SMAP overpasses; UAVSAR and AirMOSS on four days. WGEW was selected as the experiment site due to the rainfall patterns in August and existing dense networks of precipitation gages and soil moisture sensors. An additional temporary network of approximately 80 soil moisture stations was deployed in the region. Rainfall observations were supplemented with two X-band mobile scanning radars, approximately 25 tipping bucket rain gauges, three laser disdrometers, and three vertically-profiling K-band radars. Teams were on the field to take soil moisture samples for gravimetric soil moisture, bulk density and rock fraction determination as well as to measure surface roughness and vegetation water content. In this talk we will present preliminary results from the experiment including

  17. The SMAP Level 4 Surface and Root-zone Soil Moisture (L4_SM) Product

    NASA Technical Reports Server (NTRS)

    Reichle, Rolf; Crow, Wade; Koster, Randal; Kimball, John

    2010-01-01

    The Soil Moisture Active and Passive (SMAP) mission is being developed by NASA for launch in 2013 as one of four first-tier missions recommended by the U.S. National Research Council Committee on Earth Science and Applications from Space in 2007. The primary science objectives of SMAP are to enhance understanding of land surface controls on the water, energy and carbon cycles, and to determine their linkages. Moreover, the high resolution soil moisture mapping provided by SMAP has practical applications in weather and seasonal climate prediction, agriculture, human health, drought and flood decision support. In this paper we describe the assimilation of SMAP observations for the generation of the planned SMAP Level 4 Surface and Root-zone Soil Moisture (L4_SM) product. The SMAP mission makes simultaneous active (radar) and passive (radiometer) measurements in the 1.26-1.43 GHz range (L-band) from a sun-synchronous low-earth orbit. Measurements will be obtained across a 1000 km wide swath using conical scanning at a constant incidence angle (40 deg). The radar resolution varies from 1-3 km over the outer 70% of the swath to about 30 km near the center of the swath. The radiometer resolution is 40 km across the entire swath. The radiometer measurements will allow high-accuracy but coarse resolution (40 km) measurements. The radar measurements will add significantly higher resolution information. The radar is however very sensitive to surface roughness and vegetation structure. The combination of the two measurements allows optimal blending of the advantages of each instrument. SMAP directly observes only surface soil moisture (in the top 5 cm of the soil column). Several of the key applications targeted by SMAP, however, require knowledge of root zone soil moisture (approximately top 1 m of the soil column), which is not directly measured by SMAP. The foremost objective of the SMAP L4_SM product is to fill this gap and provide estimates of root zone soil moisture

  18. Science Data System Contribution to Calibrating and Validating SMAP Data Products

    NASA Astrophysics Data System (ADS)

    Cuddy, D.

    2015-12-01

    NASA's Soil Moisture Active Passive (SMAP) mission retrieves global surface soil moisture and freeze/thaw state using measurements acquired by a radiometer and a synthetic aperture radar that fly on an Earth orbiting satellite. The SMAP observatory launched from Vandenberg Air Force Base on January 31, 2015 into a near-polar, sun-synchronous orbit. This paper describes the contribution of the SMAP Science Data System (SDS) to the calibration and on-going validation of the radar backscatter and radiometer brightness temperatures. The Science Data System designed, implemented and operated the software that generates data products that contain various geophysical parameters including soil moisture and freeze/thaw states, daily maps of these geophysical parameters, as well as modeled analyses of global soil moisture and carbon flux in Boreal regions. The SDS is a fully automated system that processes the incoming raw data from the instruments, incorporates spacecraft and instrument engineering data, and uses both dynamic and static ancillary products provided by the scientific community. The standard data products appear in Hierarchical Data Format-5 (HDF5) format. These products contain metadata that conform to the ISO 19115 standard. The Alaska Satellite Facility (ASF) hosts and distributes SMAP radar data products. The National Snow and Ice Data Center (NSIDC) hosts and distributes all of the other SMAP data products.

  19. Some Issues in Validating Satellite-based Soil Moisture Retrievals with In Situ Observations and Their Impact on SMAP Validation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil Moisture Active Passive (SMAP) satellite is scheduled for launch in the fall of 2014. As the first of NASA’s Decadal Survey missions, efforts are being made to implement both best practices and innovations, which include calibration and validation of the remote sensing products (Cal/Val). ...

  20. Integrating new satellite observations from SMAP and OCO-2 for analyzing terrestrial water and carbon connections

    NASA Astrophysics Data System (ADS)

    Kimball, J. S.; Stavros, N.; Schimel, D.

    2014-12-01

    The successful inauguration of both NASA OCO-2 (Orbiting Carbon Observatory 2) and SMAP (Soil Moisture Active Passive) missions, and continuing operations from other flagship Earth Observing systems (e.g. MODIS) provide new opportunities to improve understanding of global carbon and water cycle connections over land. Carbon and water cycles interact such that soil moisture and frozen temperatures constrain net ecosystem productivity and terrestrial sources and sinks for atmospheric CO2. OCO-2 and SMAP will have overlapping global observations beginning in 2015. The combined measurements from these sensors provide complimentary information linking top-down atmospheric CO2 measurements with bottom-up carbon fluxes and underlying environmental controls. SMAP will consist of a satellite L-band radar and radiometer suite designed for global monitoring of soil moisture and freeze-thaw dynamics. SMAP science objectives include improving understanding of processes linking terrestrial water, energy and carbon cycles, and quantifying the net carbon flux in boreal landscapes. SMAP products include model enhanced estimates of net ecosystem CO2 flux (NEE) and component carbon fluxes for productivity and respiration; targeted accuracy for NEE is defined at the level of tower (FLUXNET) eddy covariance measurement based CO2 fluxes. OCO-2 has similar carbon science objectives and complimentary observations to SMAP, including canopy fluorescence (SIF) and atmosphere total column CO2 concentrations (XCO2) derived with unprecedented sampling and precision. An initial framework for integrating and analyzing these data is presented in the context of planned post-launch field campaigns and community carbon model synthesis activities. Example research applications are presented using available satellite data prior to SMAP and OCO-2 operations. Activities include using SIF (a proxy for canopy photosynthesis) with MODIS FPAR and SMAP data to improve understanding of canopy structural and

  1. Using Smos Passive Microwave Data to Develop Smap Freeze/thaw Algorithms Adapted for the Canadian Subarctic

    NASA Astrophysics Data System (ADS)

    Kalantari, P.; Bernier, M.; McDonal, K. C.; Poulin, J.

    2015-12-01

    Seasonal terrestrial Freeze/Thaw cycle in Northern Quebec Tundra (Nunavik) was determined and evaluated with passive microwave observations. SMOS time series data were analyzed to examine seasonal variations of soil freezing, and to assess the impact of land cover on the Freeze/Thaw cycle. Furthermore, the soil freezing maps derived from SMOS observations were compared to field survey data in the region near Umiujaq. The objective is to develop algorithms to follow the seasonal cycle of freezing and thawing of the soil adapted to Canadian subarctic, a territory with a high complexity of land cover (vegetation, soil, and water bodies). Field data shows that soil freezing and thawing dates vary much spatially at the local scale in the Boreal Forest and the Tundra. The results showed a satisfactory pixel by pixel mapping for the daily soil state monitoring with a > 80% success rate with in situ data for the HH and VV polarizations, and for different land cover. The average accuracies are 80% and 84% for the soil freeze period, and soil thaw period respectively. The comparison is limited because of the small number of validation pixels.

  2. SMAP L2/L3 Soil Moisture Product Validation using In Situ Based Core Validation Sites

    NASA Astrophysics Data System (ADS)

    Colliander, A.; Jackson, T. J.; Chan, S.; Das, N. N.; Kim, S.; Dunbar, R. S.; Bindlish, R.; Dang, L. B.; Berg, A. A.; Rowlandson, T. L.; Caylor, K. K.; Cosh, M. H.; AlJassar, H. K.; Lopez-baeza, E.; Martínez-Fernández, J.; Gonzales-Zamora, A.; McNairn, H.; Pacheco, A. M.; Moghaddam, M.; Montzka, C.; Notarnicola, C.; Niedrist, G.; Pellarin, T.; Pulliainen, J.; Rautiainen, K.; Ramos, J.; Seyfried, M. S.; Su, Z.; Zeng, Y.; Van der Velde, R.; Temimi, M.; Thibeault, M.; Dorigo, W.; Vreugdenhil, M.; Walker, J.; Wu, X.; Caldwell, T. G.; Spencer, M.; O'Neill, P. E.; Entekhabi, D.; Yueh, S. H.; Njoku, E. G.

    2015-12-01

    NASA's Soil Moisture Active Passive (SMAP) Mission was launched in January 2015. The objective of the mission is global mapping of soil moisture and landscape freeze/thaw state. SMAP utilizes L-band radar and radiometer instruments sharing a rotating 6-meter mesh reflector antenna. Merging of active and passive L-band observations enables an unprecedented combination of accuracy, resolution, global coverage and revisit-time for soil moisture and freeze/thaw retrievals. The primary validation reference of the data products will be ground-based measurements. Well characterized sites with calibrated in situ measurements will be used to determine the quality of the data products; these sites are designated as core validation sites. The mission success criteria will be evaluated with respect to these core site comparisons. Other remote sensing and model-based products will be used as additional resources to expand the spatial and temporal scope of the evaluation. In an effort to ensure the geographic distribution and diversity of conditions of the core validation sites, SMAP has partnered with investigators across the globe. Because different SMAP Level 2 soil moisture products have different spatial scales, the suitability of the various sites for validation of the different products must be done for each site while considering several factors. The main factors are gravimetric calibration of the sensors within a site and determination of a spatial scaling function of the sensor measurements up to the SMAP resolution scales. The mission has been able to utilize the core site measurements since the launch of the satellite because the infrastructure for data transmission and processing was established well before the launch. The validated soil moisture products will be released by May 2016. In this presentation we will show the performance of the beta version of the soil moisture products (released by November 2015) and discuss the status of the validation process.

  3. Aquarius Active-Passive RFI Environment at L-Band

    NASA Technical Reports Server (NTRS)

    Le Vine, David M.; De Matthaeis, Paolo

    2014-01-01

    Active/Passive instrument combinations (i.e., radiometer and radar) are being developed at L-band for remote sensing of sea surface salinity and soil moisture. Aquarius is already in orbit and SMAP is planned for launch in the Fall of 2014. Aquarius has provided for the first time a simultaneous look at the Radio Frequency Interference (RFI) environment from space for both active and passive instruments. The RFI environment for the radiometer observations is now reasonably well known and examples from Aquarius are presented in this manuscript that show that RFI is an important consideration for the scatterometer as well. In particular, extensive areas of the USA, Europe and Asia exhibit strong RFI in both the radiometer band at 1.41 GHz and in the band at 1.26 GHz employed by the Aquarius scatterometer. Furthermore, in areas such as the USA, where RFI at 1.4 GHz is relatively well controlled, RFI in the scatterometer band maybe the limiting consideration for the operation of combination active/passive instruments.

  4. Analysis of soil moisture retrieval from airborne passive/active L-band sensor measurements in SMAPVEX 2012

    NASA Astrophysics Data System (ADS)

    Chen, Liang; Song, Hongting; Tan, Lei; Li, Yinan; Li, Hao

    2014-11-01

    Soil moisture is a key component in the hydrologic cycle and climate system. It is an important input parameter for many hydrologic and meteorological models. NASA'S upcoming Soil Moisture Active Passive (SMAP) mission, to be launched in October 2014, will address this need by utilizing passive and active microwave measurements at L-band, which will penetrate moderately dense canopies. In preparation for the SMAP mission, the Soil Moisture Validation Experiment 2012 (SMAPVEX12) was conducted from 6 June to 17 July 2012 in the Carment-Elm Creek area in Manitoba, Canada. Over a period of six weeks diverse land cover types ranging from agriculture over pasture and grassland to forested sites were re-visited several times a week. The Passive/Active L-band Sensor (PALS) provides radiometer products, vertically and horizontally polarized brightness temperatures, and radar products. Over the past two decades, successful estimation of soil moisture has been accomplished using passive and active L-band data. However, remaining uncertainties related to surface roughness and the absorption, scattering, and emission by vegetation must be resolved before soil moisture retrieval algorithms can be applied with known and acceptable accuracy using satellite observations. This work focuses on analyzing the Passive/Active L-band Sensor observations of sites covered during SMAPVEX12, investigating the observed data, parameterizing vegetation covered surface model, modeling inversion algorithm and analyzing observed soil moisture changes over the time period of six weeks. The data and analysis results from this study are aimed at increasing the accuracy and range of validity of SMAP soil moisture retrievals via enhancing the accuracy for soil moisture retrieval.

  5. Airborne active and passive L-band measurements using PALS instrument in SMAPVEX12 soil moisture field campaign

    NASA Astrophysics Data System (ADS)

    Colliander, Andreas; Yueh, Simon; Chazanoff, Seth; Dinardo, Steven; O'Dwyer, Ian; Jackson, Thomas; McNairn, Heather; Bullock, Paul; Wiseman, Grant; Berg, Aaron; Magagi, Ramata; Njoku, Eni

    2012-10-01

    NASA's (National Aeronautics and Space Administration) Soil Moisture Active Passive (SMAP) Mission is scheduled for launch in late 2014. The objective of the mission is global mapping of soil moisture and freeze/thaw state. Merging of active and passive L-band observations of the mission will enable unprecedented combination of accuracy, resolution, coverage and revisit-time for soil moisture and freeze/thaw state retrieval. For pre-launch algorithm development and validation the SMAP project and NASA coordinated a field campaign named as SMAPVEX12 (Soil Moisture Active Passive Validation Experiment 2012) together with Agriculture and Agri-Food Canada, and other Canadian and US institutions in the vicinity of Winnipeg, Canada in June-July, 2012. The main objective of SMAPVEX12 was acquisition of a data record that features long time-series with varying soil moisture and vegetation conditions over an aerial domain of multiple parallel flight lines. The coincident active and passive L-band data was acquired with the PALS (Passive Active L-band System) instrument. The measurements were conducted over the experiment domain every 2-3 days on average, over a period of 43 days. The preliminary calibration of the brightness temperatures obtained in the campaign has been performed. Daily lake calibrations were used to adjust the radiometer calibration parameters, and the obtained measurements were compared against the raw in situ soil moisture measurements. The evaluation shows that this preliminary calibration of the data produces already a consistent brightness temperature record over the campaign duration, and only secondary adjustments and cleaning of the data is need before the data can be applied to the development and validation of SMAP algorithms.

  6. Assimilation of soil moisture retrievals or brightness temperature observations from SMOS and SMAP into the GEOS-5 land surface model

    NASA Astrophysics Data System (ADS)

    De Lannoy, G. J. M.; Reichle, R. H.

    2015-12-01

    Two L-band microwave missions are currently collecting passive microwave observations and aiming at an improved estimation of soil moisture. The ESA Soil Moisture Ocean Salinity (SMOS) mission and the NASA Soil Moisture Active Passive (SMAP) mission both provide Level 1 brightness temperature products and derived Level 2 soil moisture retrieval products. The assimilation of these products into land surface models has potential to improve global estimates of soil moisture and other land surface variables. This presentation investigates the benefits and challenges of assimilating either retrievals or brightness temperature observations from either SMOS or SMAP into the Goddard Earth Observing System (GEOS-5) land surface model. It will be shown that the seasonal corrections introduced by retrieval assimilation are slightly different from those with brightness temperature assimilation as a result of the technical implementation of the assimilation scheme. Various resulting land surface variables will also be evaluated against the results from the operational SMAP Level 4 Soil Moisture (L4_SM) product, which assimilates SMAP brightness temperature data.

  7. Spatial and Temporal Patterns of SMAP Brightness Temperatures for Use in Level 1 TB Characterization

    NASA Astrophysics Data System (ADS)

    Kim, E. J.

    2015-12-01

    1. IntroductionThe recent launch of NASA's Soil Moisture Active Passive (SMAP) mission [Entekhabi, et al] has opened the door to improved brightness temperature (TB) calibration of satellite L-band microwave radiometers, through the use of SMAP's lower noise performance and better immunity to man-made interference (vs. ESA's Soil Moisture Ocean Salinity (SMOS) mission [Kerr, et al]), better spatial resolution (vs. NASA's Aquarius sea surface salinity mission [Le Vine, et al]), and cleaner antenna pattern (vs. SMOS). All three radiometers use/used large homogeneous places on Earth's surface as calibration targets—parts of the ocean, Antarctica, and tropical forests. Despite the recent loss of Aquarius data, there is still hope for creating a longer-term L-band data set that spans the timeframe of all 3 missions. 2. Description of Analyses and Expected Results In this paper, we analyze SMAP brightness temperature data to quantify the spatial and temporal characteristics of external target areas in the oceans, Antarctica, forests, and other areas. Existing analyses have examined these targets in terms of averages, standard deviations, and other basic statistics (for Aquarius & SMOS as well). This paper will approach the problem from a signal processing perspective. Coupled with the use of SMAP's novel RFI-mitigated TBs, and the aforementioned lower noise and cleaner antenna pattern, it is expected that of the 3 L-band missions, SMAP should do the best job of characterizing such external targets. The resulting conclusions should be useful to extract the best possible TB calibration from all 3 missions, helping to inter-compare the TB from the 3 missions, and to eventually inter-calibrate the TBs into a single long-term dataset.

  8. Evaluation of the Validated Soil Moisture Product from the SMAP Radiometer

    NASA Technical Reports Server (NTRS)

    O'Neill, P.; Chan, S.; Colliander, A.; Dunbar, S.; Njoku, E.; Bindlish, R.; Chen, F.; Jackson, T.; Burgin, M.; Piepmeier, J.; Yueh, S.; Entekhabi, D.; Cosh, M.; Caldwell, T.; Walker, J.; Wu, X.; Berg, A.; Rowlandson, T.; Pacheco, A.; McNairn, H.; Thibeault, M.; Martinez-Fernandez, J.; Gonzalez-Zamora, A.; Seyfried, M.; Bosch, D.; Starks, P.; Goodrich, D.; Prueger, J.; Palecki, M.; Small, E.; Zreda, M.; Calvet, J-C.; Crow, W.; Kerr, Y.

    2016-01-01

    NASA's Soil Moisture Active Passive (SMAP) mission launched on January 31, 2015 into a sun-synchronous 6 am/6 pm orbit with an objective to produce global mapping of high-resolution soil moisture and freeze-thaw state every 2-3 days using an L-band (active) radar and an L-band (passive) radiometer. The SMAP radiometer began acquiring routine science data on March 31, 2015 and continues to operate nominally. SMAP's radiometer-derived soil moisture product (L2_SM_P) provides soil moisture estimates posted on a 36 km fixed Earth grid using brightness temperature observations from descending (6 am) passes and ancillary data. A beta quality version of L2_SM_P was released to the public in September, 2015, with the fully validated L2_SM_P soil moisture data expected to be released in May, 2016. Additional improvements (including optimization of retrieval algorithm parameters and upscaling approaches) and methodology expansions (including increasing the number of core sites, model-based intercomparisons, and results from several intensive field campaigns) are anticipated in moving from accuracy assessment of the beta quality data to an evaluation of the fully validated L2_SM_P data product.

  9. Utilization of Ancillary Data Sets for Conceptual SMAP Mission Algorithm Development and Product Generation

    NASA Technical Reports Server (NTRS)

    O'Neill, P.; Podest, E.

    2011-01-01

    The planned Soil Moisture Active Passive (SMAP) mission is one of the first Earth observation satellites being developed by NASA in response to the National Research Council's Decadal Survey, Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond [1]. Scheduled to launch late in 2014, the proposed SMAP mission would provide high resolution and frequent revisit global mapping of soil moisture and freeze/thaw state, utilizing enhanced Radio Frequency Interference (RFI) mitigation approaches to collect new measurements of the hydrological condition of the Earth's surface. The SMAP instrument design incorporates an L-band radar (3 km) and an L band radiometer (40 km) sharing a single 6-meter rotating mesh antenna to provide measurements of soil moisture and landscape freeze/thaw state [2]. These observations would (1) improve our understanding of linkages between the Earth's water, energy, and carbon cycles, (2) benefit many application areas including numerical weather and climate prediction, flood and drought monitoring, agricultural productivity, human health, and national security, (3) help to address priority questions on climate change, and (4) potentially provide continuity with brightness temperature and soil moisture measurements from ESA's SMOS (Soil Moisture Ocean Salinity) and NASA's Aquarius missions. In the planned SMAP mission prelaunch time frame, baseline algorithms are being developed for generating (1) soil moisture products both from radiometer measurements on a 36 km grid and from combined radar/radiometer measurements on a 9 km grid, and (2) freeze/thaw products from radar measurements on a 3 km grid. These retrieval algorithms need a variety of global ancillary data, both static and dynamic, to run the retrieval models, constrain the retrievals, and provide flags for indicating retrieval quality. The choice of which ancillary dataset to use for a particular SMAP product would be based on a number of factors

  10. High Spatial Resolution Soil Moisture with Passive Active Sensors Using a Change Detection Approach: Studies Using SMAPVEX12 Data

    NASA Astrophysics Data System (ADS)

    Fang, B.; Lakshmi, V.; Bindlish, R.; Jackson, T. J.

    2014-12-01

    Soil moisture is an important variable in many areas of geosciences. The passive microwave sensors have been providing soil moisture of various spatial resolutions and are available for all-weather conditions. However, restricted by the antenna diameter of microwave radiometer, the spatial resolution of passive microwave soil moisture product is at tens of kilometers and needs to be improved for many applications. The SMAP (Soil Moisture Active Passive) is set to be launched in late 2014 and will be the first mission to provide L-band radar/radiometer soil moisture retrievals at three resolutions. The SMAPVEX12 is a pre-launch field validation experiment for evaluating and testing the soil moisture retrievals acquired from SMAP satellite. Airborne data using PALS (Passive/Active L-band Sensor) at two along-track resolutions (650 m and 1590 m) and UAVSAR (Uninhabited Aerial Vehicle Synthetic Aperture Radar) at 5 m spatial resolution as well as in-situ measurements were collected during the campaign. The study will implement a Single Channel Algorithm (SCA) to retrieve soil moisture from high/low altitude PALS L-band radiometer observations, as well as produce downscaled soil moisture change by combining low spatial resolution soil moisture retrievals and high spatial resolution PALS L-band radar observations through a change-detection algorithm, which models the relationship between change in radar backscatter and the change in soil moisture.

  11. NASAs Soil Moisture Active Passive (SMAP) Mission and Opportunities For Applications Users

    NASA Technical Reports Server (NTRS)

    Brown, Molly E.; Escobar, Vanessa; Moran, Susan; Entekhabi, Dara; O'Neill, Peggy; Njoku, Eni G.; Doorn, Brad; Entin, Jared K.

    2013-01-01

    Water in the soil, both its amount (soil moisture) and its state (freeze/thaw), plays a key role in water and energy cycles, in weather and climate, and in the carbon cycle. Additionally, soil moisture touches upon human lives in a number of ways from the ravages of flooding to the needs for monitoring agricultural and hydrologic droughts. Because of their relevance to weather, climate, science, and society, accurate and timely measurements of soil moisture and freeze/thaw state with global coverage are critically important.

  12. Airborne Active and Passive L-Band Observations in Soil Moisture Active Passive Validation Experiment 2012 (SMAPVEX12)

    NASA Astrophysics Data System (ADS)

    Colliander, A.; Yueh, S. H.; Chazanoff, S.; Jackson, T. J.; McNairn, H.; Bullock, P.; Wiseman, G.; Berg, A. A.; Magagi, R.; Njoku, E. G.

    2012-12-01

    NASA's (National Aeronautics and Space Administration) Soil Moisture Active Passive (SMAP) Mission is scheduled for launch in October 2014. The objective of the mission is global mapping of soil moisture and freeze/thaw state. Merging of active and passive L-band observations of the mission will enable unprecedented combination of accuracy, resolution, coverage and revisit-time for soil moisture and freeze/thaw state retrieval. For pre-launch algorithm development and validation the SMAP project and NASA coordinated a field campaign named as SMAPVEX12 (Soil Moisture Active Passive Validation Experiment 2012) together with Agriculture and Agri-Food Canada in the vicinity of Winnipeg, Canada in June-July, 2012. The main objective of SMAPVEX12 was acquisition of data record that features long-time series with varying soil moisture and vegetation conditions (for testing the application of time-series approach) over aerial domain of multiple parallel lines (for spatial disaggregation studies). The coincident active and passive L-band data were acquired using the Passive Active L-band System (PALS), which is an airborne radiometer and radar developed for testing L-band retrieval algorithms. For SMAPVEX12 PALS was installed on a Twin Otter aircraft. The flight plan included flights at two altitudes. The higher altitude was used to map the whole experiment domain and the lower altitude was used to obtain measurements over a specific set of field sites. The spatial resolution (and swath) of the radar and radiometer from low altitude was about 600 m and from high altitude about 1500 m. The PALS acquisitions were complemented with high resolution (~10 m) L-band SAR measurements carried out by UAVSAR instrument on-board G-III aircraft. The campaign ran from June 7 until July 19. The PALS instrument conducted 17 brightness temperature and backscatter measurement flights and the UAVSAR conducted 14 backscatter measurement flights. The airborne data acquisition was supported by

  13. [Passive smoking--active killer].

    PubMed

    Palavra, Irena Rojnić; Franelić, Iva Pejnović; Milanović, Sanja Musić; Puljić, Kresimir

    2013-01-01

    Although still not perceived in this way, passive smoking is a public health issue of great importance. World Health Organization estimates that as a result of passive exposure to tobacco smoke each year 600,000 people die, of which 165,000 children. There are 33% of men, 35% of women and 40% of children who do not smoke, but are exposed to second hand smoke, and still only 11% of the world population is protected by adequate smoke-free legislation. Scientific literature provides evidence that passive exposure to tobacco smoke can result in numerous adverse health effects: asthma and allergies, respiratory infections and (middle) ear infections, cancers of various localization, accelerated atherosclerosis and cardiovascular diseases, retardation of growth and development in children, and in pregnancy it can lead to congenital anomalies and premature birth as well as lower body weight and length of the child. Certainly, the scariest consequence of all is sudden infant death syndrome, also called "death in the crib". Smoke-free policies have proven their effectiveness, but while implementing the laws, it is necessary to raise public awareness of the hazards of, both active and passive, exposure to tobacco smoke. PMID:24490334

  14. Potential of bias correction for downscaling passive microwave and soil moisture data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Passive microwave satellites such as SMOS (Soil Moisture and Ocean Salinity) or SMAP (Soil Moisture Active Passive) observe brightness temperature (TB) and retrieve soil moisture at a spatial resolution greater than most hydrological processes. Bias correction is proposed as a simple method to disag...

  15. Active and Passive Hybrid Sensor

    NASA Technical Reports Server (NTRS)

    Carswell, James R.

    2010-01-01

    A hybrid ocean wind sensor (HOWS) can map ocean vector wind in low to hurricane-level winds, and non-precipitating and precipitating conditions. It can acquire active and passive measurements through a single aperture at two wavelengths, two polarizations, and multiple incidence angles. Its low profile, compact geometry, and low power consumption permits installation on air craft platforms, including high-altitude unmanned aerial vehicles (UAVs).

  16. New Combined L-band Active/Passive Soil Moisture Retrieval Algorithm Optimized for Argentine Plains

    NASA Astrophysics Data System (ADS)

    Bruscantini, C. A.; Grings, F. M.; Salvia, M.; Ferrazzoli, P.; Karszenbaum, H.

    2015-12-01

    The ability of L-band passive microwave satellite observations to provide soil moisture (mv) measurements is well known. Despite its high sensitivity to near-surface mv, radiometric technology suffers from having a relatively low spatial resolution. Conversely active microwave observations, although their finer resolution, are difficult to be interpreted for mv content due to the confounding effects of vegetation and roughness. There have been and there are strong motivations for the realization of satellite missions that carry passive and active microwave instruments on board. This has also led to important contributions in algorithm development. In this line of work, NASA-CONAE SAC-D/Aquarius mission had on board an L band radiometer and scatterometer. This was followed by the launch of NASA SMAP mission (Soil Moisture Active Passive), as well as several airborne campaigns that provide active and passive measurements. Within this frame, a new combined active/passive mv retrieval algorithm is proposed by deriving an analytical expression of brightness temperature and radar backscattering relation using explicit semi-empirical models. Simple models (i.e. that can be easily inverted and have relatively low amount of ancillary parameters) were selected: ω-τ model (Jackson et al., 1982, Water Resources Research) and radar-only model (Narvekar et al., 2015, IEEE Transactions on Geoscience and Remote Sensing). A major challenge involves coupling the active and passive models to be consistent with observations. Coupling equations can be derived using theoretical active/passive high-order radiative transfer models, such as 3D Numerical Method of Maxwell equations (Zhou et al., 2004, IEEE Transactions on Geoscience and Remote Sensing) and Tor Vergata (Ferrazzoli et al., 1995,Remote Sensing of Environment) models. In this context, different coupling equations can be optimized for different land covers using theoretical forward models with specific parametrization for each

  17. Validation of the Soil Moisture Active Passive mission using USDA-ARS experimental watersheds

    NASA Astrophysics Data System (ADS)

    Cosh, M. H.; Jackson, T. J.; Bindlish, R.; Colliander, A.; Kim, S.; Das, N. N.; Yueh, S. H.; Bosch, D. D.; Goodrich, D. C.; Prueger, J. H.; Starks, P. J.; Livingston, S.; Seyfried, M. S.; Coopersmith, E. J.

    2015-12-01

    The calibration and validation program of the Soil Moisture Active Passive mission (SMAP) relies upon an international cooperative of in situ networks to provide ground truth references across a variety of landscapes. The USDA Agricultural Research Service operates several experimental watersheds which contribute to the validation of SMAP soil moisture products. These watersheds consist of a network of in situ sensors that measure soil moisture at a variety of depths including the 5 cm depth, which is critical for satellite validation. Comparisons of the in situ network estimates to the satellite products are ongoing, but initial results have shown strong correlation between satellite estimates and in situ soil moisture measurements once scaling functions were applied. The scaling methodologies for the in situ networks are being reviewed and evaluated. Results from the Little Washita, Fort Cobb, St. Joseph's and Little River Experimental Watersheds show good agreement between the satellite products and in situ measurements. Walnut Gulch results show high accuracy, although with the caveat that these domains are semi-arid with a substantially lower dynamic range. The South Fork Watershed is examined more closely for its detailed scaling function development as well as an apparent bias between satellite and in situ values.

  18. Model-Based Verification and Validation of the SMAP Uplink Processes

    NASA Technical Reports Server (NTRS)

    Khan, M. Omair; Dubos, Gregory F.; Tirona, Joseph; Standley, Shaun

    2013-01-01

    This case study stands as an example of how a project can validate a system-level design earlier in the project life cycle than traditional V&V processes by using simulation on a system model. Specifically, this paper describes how simulation was added to a system model of the Soil Moisture Active-Passive (SMAP) mission's uplink process.Also discussed are the advantages and disadvantages of the methods employed and the lessons learned; which are intended to benefit future model-based and simulation-based V&V development efforts.

  19. Estimating Sea Surface Salinity and Wind Using Combined Passive and Active L-Band Microwave Observations

    NASA Technical Reports Server (NTRS)

    Yueh, Simon H.; Chaubell, Mario J.

    2012-01-01

    Several L-band microwave radiometer and radar missions have been, or will be, operating in space for land and ocean observations. These include the NASA Aquarius mission and the Soil Moisture Active Passive (SMAP) mission, both of which use combined passive/ active L-band instruments. Aquarius s passive/active L-band microwave sensor has been designed to map the salinity field at the surface of the ocean from space. SMAP s primary objectives are for soil moisture and freeze/thaw detection, but it will operate continuously over the ocean, and hence will have significant potential for ocean surface research. In this innovation, an algorithm has been developed to retrieve simultaneously ocean surface salinity and wind from combined passive/active L-band microwave observations of sea surfaces. The algorithm takes advantage of the differing response of brightness temperatures and radar backscatter to salinity, wind speed, and direction, thus minimizing the least squares error (LSE) measure, which signifies the difference between measurements and model functions of brightness temperatures and radar backscatter. The algorithm uses the conjugate gradient method to search for the local minima of the LSE. Three LSE measures with different measurement combinations have been tested. The first LSE measure uses passive microwave data only with retrieval errors reaching 1 to 2 psu (practical salinity units) for salinity, and 1 to 2 m/s for wind speed. The second LSE measure uses both passive and active microwave data for vertical and horizontal polarizations. The addition of active microwave data significantly improves the retrieval accuracy by about a factor of five. To mitigate the impact of Faraday rotation on satellite observations, the third LSE measure uses measurement combinations invariant under the Faraday rotation. For Aquarius, the expected RMS SSS (sea surface salinity) error will be less than about 0.2 psu for low winds, and increases to 0.3 psu at 25 m/s wind speed

  20. Passive/Active Microwave Soil Moisture Disaggregation Using SMAPVEX12 Data

    NASA Astrophysics Data System (ADS)

    Fang, B.; Lakshmi, V.; Bindlish, R.; Jackson, T. J.; Colliander, A.

    2015-12-01

    The SMAPVEX12 experiment was conducted during June-July 2012 in Manitoba, Canada with the goal of collecting remote sensing data and ground measurements for the development and testing of soil moisture retrieval algorithms under different vegetation and soil conditions for the SMAP (Soil Moisture Active Passive) satellite launched in January 2015. The aircraft based soil moisture data provided by the passive/active microwave sensor PALS (Passive and Active L and S band System) has a nominal spatial resolution of 1500 m. In this study, a change detection algorithm is used for disaggregation of coarse passive microwave soil moisture retrievals with radar backscatter coefficients obtained with the higher spatial resolution UAVSAR (Unmanned Air Vehicle Synthetic Aperture Radar). The accuracy of the disaggregated change in soil moisture was evaluated using ground based soil moisture measurements. Results show that the disaggregation products are well correlated to in situ measurements. Based on the R2, the highest resolution disaggregated product at 5 m exhibits soil moisture heterogeneity that reflects the distribution of the crops. The difference of spatial standard deviation between the disaggregated and in situ soil moisture ranges from <0.001-0.131 m3/m3 also proves the spatial capability of the change detection algorithm at 5 m scale.

  1. Gap between active and passive solar heating

    SciTech Connect

    Balcomb, J.D.

    1985-01-01

    The gap between active and passive solar could hardly be wider. The reasons for this are discussed and advantages to narrowing the gap are analyzed. Ten years of experience in both active and passive systems are reviewed, including costs, frequent problems, performance prediction, performance modeling, monitoring, and cooling concerns. Trends are analyzed, both for solar space heating and for service water heating. A tendency for the active and passive technologies to be converging is observed. Several recommendations for narrowing the gap are presented.

  2. Sensitivity of Active and Passive Microwave Observations to Soil Moisture during Growing Corn

    NASA Astrophysics Data System (ADS)

    Judge, J.; Monsivais-Huertero, A.; Liu, P.; De Roo, R. D.; England, A. W.; Nagarajan, K.

    2011-12-01

    Soil moisture (SM) in the root zone is a key factor governing water and energy fluxes at the land surface and its accurate knowledge is critical to predictions of weather and near-term climate, nutrient cycles, crop-yield, and ecosystem productivity. Microwave observations, such as those at L-band, are highly sensitive to soil moisture in the upper few centimeters (near-surface). The two satellite-based missions dedicated to soil moisture estimation include, the European Space Agency's Soil Moisture and Ocean Salinity (SMOS) mission and the planned NASA Soil Moisture Active/Passive (SMAP) [4] mission. The SMAP mission will include active and passive sensors at L-band to provide global observations of SM, with a repeat coverage of every 2-3 days. These observations can significantly improve root zone soil moisture estimates through data assimilation into land surface models (LSMs). Both the active (radar) and passive (radiometer) microwave sensors measure radiation quantities that are functions of soil dielectric constant and exhibit similar sensitivities to SM. In addition to the SM sensitivity, radar backscatter is highly sensitive to roughness of soil surface and scattering within the vegetation. These effects may produce a much larger dynamic range in backscatter than that produced due to SM changes alone. In this study, we discuss the field observations of active and passive signatures of growing corn at L-band from several seasons during the tenth Microwave, Water and Energy Balance Experiment (MicroWEX-10) conducted in North Central Florida, and to understand the sensitivity of these signatures to soil moisture under dynamic vegetation conditions. The MicroWEXs are a series of season-long field experiments conducted during the growing seasons of sweet corn, cotton, and energy cane over the past six years (for example, [22]). The corn was planted on July 5 and harvested on September 23, 2011 during MicroWEX-10. The size of the field was 0.04 km2 and the soils

  3. Scanning L Band Active Passive Validation Experiment 2013

    NASA Astrophysics Data System (ADS)

    Joseph, A. T.; Kim, E. J.; Faulkner, T.; Patel, H.; Cosh, M. H.

    2014-12-01

    SLAP (Scanning L-band Active Passive) comprises of a fully polarimetric L-band radiometer and fully polarimetric L-band radar with a shared antenna. SLAP is designed to be compatible with several aircrafts; specifically, C-23, Twin Otter, P-3, and C-130. SLAP is designed for simplicity, accuracy, & reliability. It leverages, as much as possible, existing instruments, hardware, and software in order to minimize cost, time, and risk.The SLAP airborne/ground campaign is designed to conduct flight testing and ground truth for the airborne instrument. The campaign took place the third week of December 2013 in Eastern Shore, MD. SLAP contributes to the NASA's core mission because of its ability to serve as an airborne simulator for the SMAP (Soil Moisture Active Passive) satellite mission, one of NASA's flagship missions scheduled to launch in January 2015. A 3-day aircraft validation campaign was conducted where the new SLAP instrument flew three separate days over the proposed sampling region. The study area is a mixed agriculture and forest site located about 1 hour east of Washington, DC on the Eastern Shore (of the Chesapeake Bay). This region is located on the Delmarva Peninsula. The advantages of the selected site are: (1) Site was used before in previous field campaign (SMAPVEX08) (2) ARS HRSL has some established sampling sites within region (3) Dynamic variation in land cover (4) Variety of plant structures and densities. The goal of this campaign was to fly the instrument over the proposed site before a rain event, then have 2 other flights after the rain event to capture a dry down. In conjunction with the aircraft, there was in-situ ground sampling. Ground observations were collected concurrent with aircraft flights. These included soil moisture, soil temperature, surface temperature, surface roughness and vegetation parameters. Forest sites were monitored with small temporary networks of in situ sensors installed prior to the first flight. Soil moisture was

  4. Utilization of Airborne and in Situ Data Obtained in SGP99, SMEX02, CLASIC and SMAPVEX08 Field Campaigns for SMAP Soil Moisture Algorithm Development and Validation

    NASA Technical Reports Server (NTRS)

    Colliander, Andreas; Chan, Steven; Yueh, Simon; Cosh, Michael; Bindlish, Rajat; Jackson, Tom; Njoku, Eni

    2010-01-01

    Field experiment data sets that include coincident remote sensing measurements and in situ sampling will be valuable in the development and validation of the soil moisture algorithms of the NASA's future SMAP (Soil Moisture Active and Passive) mission. This paper presents an overview of the field experiment data collected from SGP99, SMEX02, CLASIC and SMAPVEX08 campaigns. Common in these campaigns were observations of the airborne PALS (Passive and Active L- and S-band) instrument, which was developed to acquire radar and radiometer measurements at low frequencies. The combined set of the PALS measurements and ground truth obtained from all these campaigns was under study. The investigation shows that the data set contains a range of soil moisture values collected under a limited number of conditions. The quality of both PALS and ground truth data meets the needs of the SMAP algorithm development and validation. The data set has already made significant impact on the science behind SMAP mission. The areas where complementing of the data would be most beneficial are also discussed.

  5. Market ecology of active and passive investors

    NASA Astrophysics Data System (ADS)

    Capocci, Andrea; Zhang, Yi-Cheng

    2001-09-01

    We study the role of active and passive investors in an investment market with uncertainties. Active investors concentrate on a single or a few stocks with a given probability of determining the quality of them. Passive investors spread their investment uniformly, resembling buying the market index. In this toy market stocks are introduced as good and bad. If a stock receives sufficient investment it will survive, otherwise die. Active players exert a selective pressure since they can determine to an extent the investment quality. We show that the active players provide the driving force, whereas the passive ones act as free riders. While their gains do not differ too much, we show that the active players enjoy an edge. Their presence also provides better gains to the passive players and stocks themselves.

  6. Passivation of fluorinated activated charcoal

    SciTech Connect

    Del Cul, G.D.; Trowbridge, L.D.; Simmons, D.W.; Williams, D.F.; Toth, L.M.

    1997-10-01

    The Molten Salt Reactor Experiment (MSRE), at the Oak Ridge National Laboratory has been shut down since 1969 when the fuel salt was drained from the core into two Hastelloy N tanks at the reactor site. In 1995, a multiyear project was launched to remediate the potentially hazardous conditions generated by the movement of fissile material and reactive gases from the storage tanks into the piping system and an auxiliary charcoal bed (ACB). The top 12 in. of the ACB is known by gamma scan and thermal analysis to contain about 2.6 kg U-233. According to the laboratory tests, a few feet of fluorinated charcoal are believed to extend beyond the uranium front. The remainder of the ACB should consist of unreacted charcoal. Fluorinated charcoal, when subjected to rapid heating, can decompose generating gaseous products. Under confined conditions, the sudden exothermic decomposition can produce high temperatures and pressures of near-explosive characteristics. Since it will be necessary to drill and tap the ACB to allow installation of piping and instrumentation for remediation and recovery activities, it is necessary to chemically convert the reactive fluorinated charcoal into a more stable material. Ammonia can be administered to the ACB as a volatile denaturing agent that results in the conversion of the C{sub x}F to carbon and ammonium fluoride, NH{sub 4}F. The charcoal laden with NH{sub 4}F can then be heated without risking any sudden decomposition. The only consequence of heating the treated material will be the volatilization of NH{sub 4}F as a mixture of NH{sub 3} and HF, which would primarily recombine as NH{sub 4}F on surfaces below 200 C. The planned scheme for the ACB denaturing is to flow diluted ammonia gas in steps of increasing NH{sub 3} concentration, 2% to 50%, followed by the injection of pure ammonia. This report summarizes the planned passivation treatment scheme to stabilize the ACB and remove the potential hazards. It also includes basic information

  7. Active colloids that slosh through passive matrices

    NASA Astrophysics Data System (ADS)

    Zhang, Jie; Granick, Steve

    Studies of natural and artificial active matter have focused on systems with a large mismatch of the time and length scales for active and passive elements, but in a variety of non-equilibrium condensed matter systems, including numerous biological processes, actively driven elements have a crowded environment of surrounding passive ``solvent'' elements of comparable size. Here we study self-propelled colloidal particles in a passive matrix of comparable size. Particles with high activity take straight lines and sharp turns through the soft 2-D crystal matrix to ensure rapid healing of the crystal structure. Effective attraction between active particles arises when the concentration of active particles or the hardness of the matrix increases; active particles tend to segregate in the grain boundaries of the crystal matrix.

  8. Modeling regional crop yield and irrigation demand using SMAP type of soil moisture data

    NASA Astrophysics Data System (ADS)

    El Sharif, H. A.; Wang, J.; Georgakakos, A. P.; Bras, R. L.

    2013-12-01

    Agricultural models, such as Decision Support System for Agrotechnology Transfer - Cropping Systems Model (DSSAT-CSM) (Tsuji, et al., 1994), have been developed to predict the yield of various crops at field and regional scales. The model simulations of crop yields provide essential information for water resources management. One key input of the agricultural models is soil moisture. So far there are no observed soil moisture data covering the entire US with adequate time (daily) and space (1 km or less) resolutions preferred for model simulation of crop yields. Spatially and temporally downscaled data from the upcoming Soil Moisture Active Passive (SMAP) mission can fill this data gap through the generation of fine resolution soil moisture maps that can be incorporated into DSSAT-CSM model. This study will explore the impact downscaled remotely-sensed soil moisture data can have on agricultural model forecasts of agricultural yield and irrigation demand using synthetically generated data sets exhibiting statistical characteristics (uncertainty) similar to the upcoming SMAP products. It is expected that incorporating this data into agricultural model will prove especially useful for cases in which soil water conductivity characteristics and/or precipitation amount at a specific site of interest are not fully known; furthermore, a proposed Bayesian analysis is expected to generate a soil moisture sequence that reduces the uncertainty in modeled yield and irrigation demand compared to using downscaled remotely-sensed soil moisture or precipitation data alone. References Tsuji, G., Uehara, G., and Balas, S. (1994). DSSAT V3, University of Hawaii, Honolulu.

  9. Sunspot Time Series: Passive and Active Intervals

    NASA Astrophysics Data System (ADS)

    Zięba, S.; Nieckarz, Z.

    2014-07-01

    Solar activity slowly and irregularly decreases from the first spotless day (FSD) in the declining phase of the old sunspot cycle and systematically, but also in an irregular way, increases to the new cycle maximum after the last spotless day (LSD). The time interval between the first and the last spotless day can be called the passive interval (PI), while the time interval from the last spotless day to the first one after the new cycle maximum is the related active interval (AI). Minima of solar cycles are inside PIs, while maxima are inside AIs. In this article, we study the properties of passive and active intervals to determine the relation between them. We have found that some properties of PIs, and related AIs, differ significantly between two group of solar cycles; this has allowed us to classify Cycles 8 - 15 as passive cycles, and Cycles 17 - 23 as active ones. We conclude that the solar activity in the PI declining phase (a descending phase of the previous cycle) determines the strength of the approaching maximum in the case of active cycles, while the activity of the PI rising phase (a phase of the ongoing cycle early growth) determines the strength of passive cycles. This can have implications for solar dynamo models. Our approach indicates the important role of solar activity during the declining and the rising phases of the solar-cycle minimum.

  10. Vertical Diffusivities of Active and Passive Tracers

    NASA Technical Reports Server (NTRS)

    Canuto, V. M.; Cheng, Y.; Howard, A. M.

    2010-01-01

    The climate models that include a carbon-cycle need the vertical diffusivity of a passive tracer. Since an expression for the latter is not available, it has been common practice to identify it with that of salt. The identification is questionable since T, S are active, not passive tracers. We present the first derivation of the diffusivity of a passive tracer in terms of Ri (Richardson number) and Rq (density ratio, ratio of salinity over temperature z-gradients). The following results have emerged: (a) The passive tracer diffusivity is an algebraic function of Ri, Rq. (b) In doubly stable regimes (DS, partial derivative of T with respect to z > 0, partial derivative of S with respect to z < 0), the passive scalar diffusivity is nearly the same as that of salt/heat for any values of Rq < 0 and Ri > 0. (c) In DC regimes (diffusive convection, partial derivative of T with respect to z < 0, partial derivative of S with respect to z < 0, Rq > 1), the passive scalar diffusivity is larger than that of salt. At Ri = O(1), it can be more than twice as large. (d) In SF regimes (salt fingers, partial derivative of T with respect to z > 0, partial derivative of S with respect to z > 0, Rq < 1), the passive scalar diffusivity is smaller than that of salt. At Ri = O(1), it can be less than half of it. (e) The passive tracer diffusivity predicted at the location of NATRE (North Atlantic Tracer Release Experiment) is discussed. (f) Perhaps the most relevant conclusion is that the common identification of the tracer diffusivity with that of salt is valid only in DS regimes. In the Southern Ocean, where there is the largest CO2 absorption, the dominant regime is diffusive convection discussed in (c) above.

  11. Evaluation of Radar Vegetation Indices for Vegetation Water Content Estimation Using Data from a Ground-Based SMAP Simulator

    NASA Technical Reports Server (NTRS)

    Srivastava, Prashant K.; O'Neill, Peggy; Cosh, Michael; Lang, Roger; Joseph, Alicia

    2015-01-01

    Vegetation water content (VWC) is an important component of microwave soil moisture retrieval algorithms. This paper aims to estimate VWC using L band active and passive radar/radiometer datasets obtained from a NASA ground-based Soil Moisture Active Passive (SMAP) simulator known as ComRAD (Combined Radar/Radiometer). Several approaches to derive vegetation information from radar and radiometer data such as HH, HV, VV, Microwave Polarization Difference Index (MPDI), HH/VV ratio, HV/(HH+VV), HV/(HH+HV+VV) and Radar Vegetation Index (RVI) are tested for VWC estimation through a generalized linear model (GLM). The overall analysis indicates that HV radar backscattering could be used for VWC content estimation with highest performance followed by HH, VV, MPDI, RVI, and other ratios.

  12. Generating passive NIR images from active LIDAR

    NASA Astrophysics Data System (ADS)

    Hagstrom, Shea; Broadwater, Joshua

    2016-05-01

    Many modern LIDAR platforms contain an integrated RGB camera for capturing contextual imagery. However, these RGB cameras do not collect a near-infrared (NIR) color channel, omitting information useful for many analytical purposes. This raises the question of whether LIDAR data, collected in the NIR, can be used as a substitute for an actual NIR image in this situation. Generating a LIDAR-based NIR image is potentially useful in situations where another source of NIR, such as satellite imagery, is not available. LIDAR is an active sensing system that operates very differently from a passive system, and thus requires additional processing and calibration to approximate the output of a passive instrument. We examine methods of approximating passive NIR images from LIDAR for real-world datasets, and assess differences with true NIR images.

  13. SMAP Global Model Calibration Using SMOS Time-Series Observations

    NASA Astrophysics Data System (ADS)

    Chan, S.; Njoku, E. G.; Bindlish, R.; O'Neill, P. E.; Jackson, T. J.

    2014-12-01

    Within the suite of SMAP's standard data products is the Level 2 Passive Soil Moisture Product, which is derived primarily from SMAP's brightness temperature (TB) observations. The baseline retrieval algorithm uses an established microwave emission model that had been extensively tested in many past field experiments. One approach to applying the same model at a global scale with SMAP's TB observations is to use the same calibration coefficients derived from past field experiments and apply them globally. Although this approach is a simplification of reality, it resulted in accurate retrieval in several geographically limited studies. Nevertheless, significant retrieval bias may occur in areas where land cover types had not been considered in past field experiments. In this work, a time-series global model calibration approach is proposed and evaluated. One year of gridded L-band TB observations from the Soil Moisture and Ocean Salinity (SMOS) mission were used as the primary input. At each land pixel on the SMAP grid, the observed TBs were compared with the simulated TBs according to the model with unknown calibration coefficients to be determined. Because of the time-series nature of the input, the above comparison could be repeated for successive revisit dates as a system of equations until the number of known variables (TBs) exceeds the number of unknown variables (calibration coefficients and/or geophysical retrieval). Global nonlinear optimization techniques were then applied to the equations to solve for the optimal model calibration coefficients for that pixel. Following global application of this approach, soil moisture estimates were extracted and compared with in-situ ground measurement. The resulting soil moisture estimates were shown to have an accuracy comparable to what was observed in past field experiments, confirming the versatility of this global model calibration approach.

  14. Multipurpose active/passive motion compensation system

    SciTech Connect

    Sullivan, R.A.; Clements, R.E.; Davenport, M.R.

    1984-05-01

    A microprocessor-controlled active/passive motion compensation system has been developed for deploying a variety of geotechnical in-situ testing devices with mobile drilling rigs from low-cost service vessels. The light-weight rotary heave compensator incorporates a hydraulic motor as the compensator actuator and a servo-controlled closed loop pump to reduce the air storage and power requirements. Unique features of the system are the use of inertial sensors to measure three components of boat motion, the ability to run the system in active/passive or passive modes, and the ability to automatically lower the drillstring at a constant velocity while maintaining motion compensation. Quantitative measurements made during sea trials offshore California yielded motion compensation accuracy approaching 98 percent which is much better than the compensation achieved with passive systems. Results are presented from offshore in-situ testing with a cone penetrometer, a vane shear device, and a suspension PS logger. The system can also be used for other offshore applications.

  15. PCM Passive Cooling System Containing Active Subsystems

    NASA Technical Reports Server (NTRS)

    Blanding, David E.; Bass, David I.

    2005-01-01

    A multistage system has been proposed for cooling a circulating fluid that is subject to intermittent intense heating. The system would be both flexible and redundant in that it could operate in a basic passive mode, either sequentially or simultaneously with operation of a first, active cooling subsystem, and either sequentially or simultaneously with a second cooling subsystem that could be active, passive, or a combination of both. This flexibility and redundancy, in combination with the passive nature of at least one of the modes of operation, would make the system more reliable, relative to a conventional cooling system. The system would include a tube-in-shell heat exchanger, within which the space between the tubes would be filled with a phase-change material (PCM). The circulating hot fluid would flow along the tubes in the heat exchanger. In the basic passive mode of operation, heat would be conducted from the hot fluid into the PCM, wherein the heat would be stored temporarily by virtue of the phase change.

  16. The Soil Moisture Active Passive Marena Oklahoma In Situ Sensor Testbed (SMAP-MOISST): Design and initial results

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In situ soil moisture monitoring networks are critical to the development of soil moisture remote sensing missions as well as agricultural and environmental management, weather forecasting and many other endeavors. These in situ networks are composed of a variety of sensors and installation practic...

  17. 26 CFR 1.469-2 - Passive activity loss.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... than a passive activity and as an interest in property held for investment for any period during which... paragraph (c)(2)(iii) as used in an activity other than a passive activity and as held for investment for... 26 Internal Revenue 6 2014-04-01 2014-04-01 false Passive activity loss. 1.469-2 Section...

  18. Propulsion by active and passive airfoil oscillation

    NASA Astrophysics Data System (ADS)

    Mackowski, A. W.; Williamson, C. H. K.

    2013-11-01

    Oscillating airfoils have been the subject of much research both as a mechanism of propulsion in engineering devices as well as a model of understanding how fish, birds, and insects produce thrust and maneuvering forces. Additionally, the jet or wake generated by an oscillating airfoil exhibits a multitude of vortex patterns, which are an interesting study in their own right. We present PIV measurements of the vortex flow behind an airfoil undergoing controlled pitching oscillations at moderate Reynolds number. As a method of propulsion, oscillating foils have been found to be capable performers when undergoing both pitching and heaving motions [Anderson et al. 1998]. While an airfoil undergoing only pitching motion is a relatively inefficient propulsor, we examine the effect of adding passive dynamics to the system: for example, actuated pitching with a passive spring in the heave direction. Practically speaking, a mechanical system with such an arrangement has the potential to reduce the cost and complexity of an oscillating airfoil propulsor. To study an airfoil undergoing both active and passive motion, we employ our ``cyber-physical fluid dynamics'' technique [Mackowski & Williamson, 2011] to simulate the effects of passive dynamics in a physical experiment.

  19. Modeling of active and passive nonlinear metamaterials

    NASA Astrophysics Data System (ADS)

    Colestock, Patrick L.; Reiten, Matthew T.; O'Hara, John F.

    2012-11-01

    We develop general results for nonlinear metamaterials based on simple circuit models that reflect the elementary nonlinear behavior of the medium. In particular, we consider both active and passive nonlinearities which can lead to gain, harmonic generation and a variety of nonlinear waves depending on circuit parameters and signal amplitude. We show that the medium can exhibit a phase transition to a synchronized state and derive conditions for the transformation based on a widely used multiple time scale approach that leads to the well-known Complex Ginzburg-Landau equation. Further, we examine the variety of nonlinear waves that can exist in such systems, and we present numerical results for both active and passive metamaterial cases.

  20. Active versus passive damping in large flexible structures

    NASA Technical Reports Server (NTRS)

    Slater, Gary L.; Mclaren, Mark D.

    1991-01-01

    Optimal passive and active damping control can be considered in the context of a general control/structure optimization problem. Using a mean square output response approach, it is shown that the weight sensitivity of the active and passive controllers can be used to determine an optimal mix of active and passive elements in a flexible structure.

  1. Bacteriological evaluation of passive ultrasonic activation.

    PubMed

    Spoleti, Pablo; Siragusa, Martha; Spoleti, María Julia

    2003-01-01

    The purpose of this study was to evaluate the influence of passive ultrasonic activation on root canal disinfection. Sixty human teeth (group A: upper incisors, group B: upper canines, and group C: distobuccal root of first upper molars) were selected and sterilized in an autoclave. A standardized inoculum was placed into the canals, and they were incubated for 72 h at 37 degrees C. Then, they were divided into subgroup 1, which received sterile saline (SS) as an irrigant, and subgroup 2, which received sterile saline with passive ultrasonic activation (SU). The endodontic treatment was performed with a crown-down technique. Bacteriological identification of surviving colonies was carried out. Surviving colonies were higher when ultrasonics was not used (group A: SS: x 32.13, SU: x 13.53; group B: SS: x 53.70, SU: x 44.60; group C: SS: x 39.16, SU: x 29.40). The homogeneity proportion tests to compare the results of both subgroups showed that the surviving proportions were higher (p = 0.01) when the ultrasonic activation was not used. PMID:12540211

  2. Synergistic Use of SMOS Measurements with SMAP Derived and In-situ Data over Valencia Anchor Station by Using Downscaling Technique

    NASA Astrophysics Data System (ADS)

    Ansari Amoli, Abdolreza; Lopez-Baeza, Ernesto; Mahmoudi, Ali; Mahmoodi, Ali

    2016-07-01

    Synergistic Use of SMOS Measurements with SMAP Derived and In-situ Data over the Valencia Anchor Station by Using a Downscaling Technique Ansari Amoli, A.(1),Mahmoodi, A.(2) and Lopez-Baeza, E.(3) (1) Department of Earth Physics and Thermodynamics, University of Valencia, Spain (2) Centre d'Etudes Spatiales de la BIOsphère (CESBIO), France (3) Department of Earth Physics and Thermodynamics, University of Valencia, Spain Soil moisture products from active sensors are not operationally available. Passive remote sensors return more accurate estimates, but their resolution is much coarser. One solution to overcome this problem is the synergy between radar and radiometric data by using disaggregation (downscaling) techniques. Few studies have been conducted to merge high resolution radar and coarse resolution radiometer measurements in order to obtain an intermediate resolution product. In this paper we present an algorithm using combined available SMAP (Soil Moisture Active and Passive) radar and SMOS (Soil Moisture and Ocean Salinity) radiometer measurements to estimate surface soil moisture over the Valencia Anchor Station (VAS), Valencia, Spain. The goal is to combine the respective attributes of the radar and radiometer observations to estimate soil moisture at a resolution of 3 km. The algorithm disaggregates the coarse resolution SMOS (15 km) radiometer brightness temperature product based on the spatial variation of the high resolution SMAP (3 km) radar backscatter. The disaggregation of the radiometer brightness temperature uses the radar backscatter spatial patterns within the radiometer footprint that are inferred from the radar measurements. For this reason the radar measurements within the radiometer footprint are scaled by parameters that are derived from the temporal fluctuations in the radar and radiometer measurements.

  3. Passive versus active mitigation cost analysis

    SciTech Connect

    Parazin, R.J.; Galbraith, J.D.

    1995-04-01

    The scope of this task is to assess the impact of mitigation alternatives for Tanks 241-SY-101 and 241-SY-103 on the Project W-236A Multi-Function Waste Tank Facility. This assessment and other related tasks are part of an Action Plan Path Forward prepared by the Tank Waste Remediation System (TWRS) Life Extension and Transition Program. Task 3.7 of the Action Plan for Project W-236A MWTF analyzed the comparative cost/risk of two hydrogen gas mitigation alternatives (active versus passive) to recommend the most appropriate course of action to resolve the hydrogen gas safety issue. The qualitative success of active mitigation has been demonstrated through Tank 241-SY-101 testing. Passive mitigation has not been demonstrated but will be validated by laboratory test work performed under Task 3.1 of the Action Plan. It is assumed for this assessment that the uncertainties associated with the performance of either alternative is comparable. Determining alternative specific performance measures beyond those noted are not in the scope of this effort.

  4. Brain activation associated with active and passive lower limb stepping

    PubMed Central

    Jaeger, Lukas; Marchal-Crespo, Laura; Wolf, Peter; Riener, Robert; Michels, Lars; Kollias, Spyros

    2014-01-01

    Reports about standardized and repeatable experimental procedures investigating supraspinal activation in patients with gait disorders are scarce in current neuro-imaging literature. Well-designed and executed tasks are important to gain insight into the effects of gait-rehabilitation on sensorimotor centers of the brain. The present study aims to demonstrate the feasibility of a novel imaging paradigm, combining the magnetic resonance (MR)-compatible stepping robot (MARCOS) with sparse sampling functional magnetic resonance imaging (fMRI) to measure task-related BOLD signal changes and to delineate the supraspinal contribution specific to active and passive stepping. Twenty-four healthy participants underwent fMRI during active and passive, periodic, bilateral, multi-joint, lower limb flexion and extension akin to human gait. Active and passive stepping engaged several cortical and subcortical areas of the sensorimotor network, with higher relative activation of those areas during active movement. Our results indicate that the combination of MARCOS and sparse sampling fMRI is feasible for the detection of lower limb motor related supraspinal activation. Activation of the anterior cingulate and medial frontal areas suggests motor response inhibition during passive movement in healthy participants. Our results are of relevance for understanding the neural mechanisms underlying gait in the healthy. PMID:25389396

  5. Using SMAP data to improve drought early warning over the US Great Plains

    NASA Astrophysics Data System (ADS)

    Fu, R.; Fernando, N.; Tang, W.

    2015-12-01

    A drought prone region such as the Great Plains of the United States (US GP) requires credible and actionable drought early warning. Such information cannot simply be extracted from available climate forecasts because of their large uncertainties at regional scales, and unclear connections to the needs of the decision makers. In particular, current dynamic seasonal predictions and climate projections, such as those produced by the NOAA North American Multi-Model Ensemble experiment (NMME) are much more reliable for winter and spring than for the summer season for the US GP. To mitigate the weaknesses of dynamic prediction/projections, we have identified three key processes behind the spring-to-summer dry memory through observational studies, as the scientific basis for a statistical drought early warning system. This system uses percentile soil moisture anomalies in spring as a key input to provide a probabilistic summer drought early warning. The latter outperforms the dynamic prediction over the US Southern Plains and has been used by the Texas state water agency to support state drought preparedness. A main source of uncertainty for this drought early warning system is the soil moisture input obtained from the NOAA Climate Forecasting System (CFS). We are testing use of the beta version of NASA Soil Moisture Active Passive (SMAP) soil moisture data, along with the Soil Moisture and Ocean Salinity (SMOS), and the long-term Essential Climate Variable Soil Moisture (ECV-SM) soil moisture data, to reduce this uncertainty. Preliminary results based on ECV-SM suggests satellite based soil moisture data could improve early warning of rainfall anomalies over the western US GP with less dense vegetation. The skill degrades over the eastern US GP where denser vegetation is found. We evaluate our SMAP-based drought early warning for 2015 summer against observations.

  6. The SoilSCAPE Network Multiscale In-situ Soil Moisture Measurements: Innovations in Network Design and Approaches to Upscaling in Support of SMAP

    NASA Astrophysics Data System (ADS)

    Moghaddam, M.; Clewley, D.; Silva, A.; Akbar, R.

    2014-12-01

    The Soil Moisture Active Passive (SMAP) mission will provide soil moisture at 3, 9, and 36 km scales through the use of radar and radiometer data. To validate SMAP products, in-situ sensors are required. Typically, validation plans consist of several sensors installed nearly uniformly in the scene. To upscale the soil moisture estimates to the scales of SMAP products requires a large number of sensors, distributed throughout the instrument footprint. Even for the higher resolution SMAP products (3 km) there are often insufficient sensors available within a resolution cell. The Soil moisture Sensing Controller and oPtimal Estimator (SoilSCAPE) project provides a new adaptive validation strategy, including upscaled estimates of soil moisture. By utilizing smarter network technology and optimized sensor placement, more representative measurements of soil moisture are obtained, at a range of spatial scales with lower costs than traditional networks. A large network was established around the Tonzi Ranch site in central California. The network design comprises multiple sites, each with a 10-30 node cluster taking measurements from up to 4 sensors installed at different depths. The nodes wirelessly communicate to a Local Coordinator, which collects data and transmits to a server (http://soilscape.usc.edu). Each node can communicate with the Coordinator up to a distance of 400m. Each station supports up to 60 nodes. Currently 111 nodes have been installed over 6 sites. The SoilSCAPE nonuniform placement of sensors requires novel upscaling methods. Previous studies have used regression, which works well when the measurement is well correlated with other variables. However, soil moisture dependence on various variables could be complex and nonlinear. To account for such complexities, we use the Random Forests algorithm, which is capable of modeling complex non-linear system and can handle continuous and categorical data. The algorithm has not previously been applied to

  7. Passive and active middle ear implants

    PubMed Central

    Beutner, Dirk; Hüttenbrink, Karl-Bernd

    2011-01-01

    Besides eradication of chronic middle ear disease, the reconstruction of the sound conduction apparatus is a major goal of modern ear microsurgery. The material of choice in cases of partial ossicular replacement prosthesis is the autogenous ossicle. In the event of more extensive destruction of the ossicular chain diverse alloplastic materials, e.g. metals, ceramics, plastics or composits are used for total reconstruction. Their specialised role in conducting sound energy within a half-open implant bed sets high demands on the biocompatibility as well as the acoustic-mechanic properties of the prosthesis. Recently, sophisticated titanium middle ear implants allowing individual adaptation to anatomical variations are widely used for this procedure. However, despite modern developments, hearing restoration with passive implants often faces its limitations due to tubal-middle-ear dysfunction. Here, implantable hearing aids, successfully used in cases of sensorineural hearing loss, offer a promising alternative. This article reviews the actual state of affairs of passive and active middle ear implants. PMID:22073102

  8. The active-passive continuous-wave terahertz imaging system

    NASA Astrophysics Data System (ADS)

    Dolganova, Irina N.; Zaytsev, Kirill I.; Metelkina, Anna A.; Yurchenko, Stanislav O.

    2016-08-01

    Active and passive terahertz (THz) imaging have recently become essential instruments of various THz applications. In this paper the active- and passive-mode THz imaging systems are studied and the hybrid active-passive THz imaging system is suggested. The concept of image contrast was used to compare the active and passive THz imaging results. In order to achieve better image quality the hybrid system is considered to be effective. The main advantage of the proposed system is the combination of the self-emitted radiation of the object with the back scattered source radiation. The experimental results demonstrate that the active-passive modality of THz imaging system allows retrieving maximum information about the object. An approach to synthesise the active-passive THz images was proposed using the false-color representation.

  9. Active and passive contributions to spatial learning.

    PubMed

    Chrastil, Elizabeth R; Warren, William H

    2012-02-01

    It seems intuitively obvious that active exploration of a new environment will lead to better spatial learning than will passive exposure. However, the literature on this issue is decidedly mixed-in part, because the concept itself is not well defined. We identify five potential components of active spatial learning and review the evidence regarding their role in the acquisition of landmark, route, and survey knowledge. We find that (1) idiothetic information in walking contributes to metric survey knowledge, (2) there is little evidence as yet that decision making during exploration contributes to route or survey knowledge, (3) attention to place-action associations and relevant spatial relations contributes to route and survey knowledge, although landmarks and boundaries appear to be learned without effort, (4) route and survey information are differentially encoded in subunits of working memory, and (5) there is preliminary evidence that mental manipulation of such properties facilitates spatial learning. Idiothetic information appears to be necessary to reveal the influence of attention and, possibly, decision making in survey learning, which may explain the mixed results in desktop virtual reality. Thus, there is indeed an active advantage in spatial learning, which manifests itself in the task-dependent acquisition of route and survey knowledge.

  10. Soil Moisture Active Passive Mission L4_C Data Product Assessment (Version 2 Validated Release)

    NASA Technical Reports Server (NTRS)

    Kimball, John S.; Jones, Lucas A.; Glassy, Joseph; Stavros, E. Natasha; Madani, Nima; Reichle, Rolf H.; Jackson, Thomas; Colliander, Andreas

    2016-01-01

    The SMAP satellite was successfully launched January 31st 2015, and began acquiring Earth observation data following in-orbit sensor calibration. Global data products derived from the SMAP L-band microwave measurements include Level 1 calibrated and geolocated radiometric brightness temperatures, Level 23 surface soil moisture and freezethaw geophysical retrievals mapped to a fixed Earth grid, and model enhanced Level 4 data products for surface to root zone soil moisture and terrestrial carbon (CO2) fluxes. The post-launch SMAP mission CalVal Phase had two primary objectives for each science product team: 1) calibrate, verify, and improve the performance of the science algorithms, and 2) validate accuracies of the science data products as specified in the L1 science requirements. This report provides analysis and assessment of the SMAP Level 4 Carbon (L4_C) product pertaining to the validated release. The L4_C validated product release effectively replaces an earlier L4_C beta-product release (Kimball et al. 2015). The validated release described in this report incorporates a longer data record and benefits from algorithm and CalVal refinements acquired during the SMAP post-launch CalVal intensive period. The SMAP L4_C algorithms utilize a terrestrial carbon flux model informed by SMAP soil moisture inputs along with optical remote sensing (e.g. MODIS) vegetation indices and other ancillary biophysical data to estimate global daily net ecosystem CO2 exchange (NEE) and component carbon fluxes for vegetation gross primary production (GPP) and ecosystem respiration (Reco). Other L4_C product elements include surface (10 cm depth) soil organic carbon (SOC) stocks and associated environmental constraints to these processes, including soil moisture and landscape freeze/thaw (FT) controls on GPP and respiration (Kimball et al. 2012). The L4_C product encapsulates SMAP carbon cycle science objectives by: 1) providing a direct link between terrestrial carbon fluxes and

  11. 26 CFR 1.469-3 - Passive activity credit.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 6 2013-04-01 2013-04-01 false Passive activity credit. 1.469-3 Section 1.469-3...) INCOME TAXES (CONTINUED) Taxable Year for Which Deductions Taken § 1.469-3 Passive activity credit. (a)-(d) (e) Coordination with section 38(b). Any credit described in section 38(b) (1) through (5)...

  12. 26 CFR 1.469-3 - Passive activity credit.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 6 2014-04-01 2014-04-01 false Passive activity credit. 1.469-3 Section 1.469-3...) INCOME TAXES (CONTINUED) Taxable Year for Which Deductions Taken § 1.469-3 Passive activity credit. (a)-(d) (e) Coordination with section 38(b). Any credit described in section 38(b) (1) through (5)...

  13. 26 CFR 1.469-3 - Passive activity credit.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 6 2012-04-01 2012-04-01 false Passive activity credit. 1.469-3 Section 1.469-3...) INCOME TAXES (CONTINUED) Taxable Year for Which Deductions Taken § 1.469-3 Passive activity credit. (a)-(d) (e) Coordination with section 38(b). Any credit described in section 38(b) (1) through (5)...

  14. Combined active and passive microwave remote sensing of soil moisture for vegetated surfaces at L-band

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The distorted Born approximation (DBA) combined with the numerical solutions of Maxwell equations (NMM3D) has been used for the radar backscattering model for the SMAP mission. The models for vegetated surfaces such as wheat, grass, soybean and corn have been validated with the Soil Moisture Active ...

  15. Passive and Active Fiber Optic Components

    NASA Astrophysics Data System (ADS)

    Digonnet, Michel Jean-Francois

    This thesis is concerned with the development and characterization of both passive and active fiber-optic components for applications in single-mode fiber systems, in particular in the new technology of fiber sensors and signal processors. These components include single-mode fiber directional couplers, vital to many optical fiber systems, all-fiber wavelength multiplexers, with potential applications in communication systems and active fiber devices, and single-crystal fiber lasers and amplifiers as miniature light sources and signal regenerators. The fiber directional couplers involved in this work, fabricated by a polishing process, are described in detail. Experimental characterization of their coupling, loss and unique tuning properties, and their respective dependence on the coupler geometrical parameters, are reported. A theoretical model of fiber-to-fiber coupling is also developed and shown to be a very useful and accurate tool in the design and study of this type of fiber couplers. The dependence of the coupling properties of fiber couplers on the signal wavelength is studied both theoretically and experimentally for applications in wavelength division multiplexing. All-fiber multiplexers exhibiting a good wavelength selectivity and unique tunability are described and shown to operate according to the coupler model. Work on active fiber devices explores the potential of the new technology of single-crystal fibers grown by the laser-heated floating-zone technique. The status of crystal fiber growth is reported, together with the basic physical and optical characteristics of these fibers. A theoretical model of the effects of fiber model structure on the gain and laser operation of active fibers is also developed to predict the performance of lasers and amplifiers in a fiber form. Several conceptual pumping schemes are described which offer solutions to the difficult problem of optically pumping small diameter fiber amplifiers. The experimental

  16. Optimum mix of passive and active control of space structures

    NASA Technical Reports Server (NTRS)

    Rogers, Lynn; Richards, Ken

    1987-01-01

    The objective of this research was to test vibration suppression (settling time and jitter) of a large space structure (LSS) characterized by low frequency high global vibration modes. Five percent passive damping in a large truss was analyzed, tested and correlated. A representative system article re-target analysis shows that modest levels of passive damping dramatically reduce the control energy required. LSS must incorporate passive damping from the outset. The LSS system performance will not be met by either active or passive damping alone.

  17. Prescribing Activities that Engage Passive Residents. An Innovative Method

    PubMed Central

    Kolanowski, Ann; Buettner, Linda

    2009-01-01

    Individuals with dementia are often passive, which places them at risk for further cognitive and functional decline. Recreational activities have been used in research to reduce passive behaviors, but systematic reviews of these studies have found modest effect sizes for many activities. In this article, we describe the further theoretical development of an innovative method for prescribing activities that have a high likelihood of engaging nursing home residents who are passive and present examples for research application and clinical practice. This method may increase the effect size of activity interventions and encourage more widespread adoption of nonpharmacological interventions in practice. PMID:18274300

  18. Analysis of scapular kinematics during active and passive arm elevation

    PubMed Central

    Kai, Yoshihiro; Gotoh, Masafumi; Takei, Kazuto; Madokoro, Kazuya; Imura, Takeshi; Murata, Shin; Morihara, Toru; Shiba, Naoto

    2016-01-01

    [Purpose] Early postoperative passive motion exercise after arthroscopic rotator cuff repair remains controversial. To better understand this issue, this study was aimed at evaluating scapular kinematics and muscle activities during passive arm elevation in healthy subjects. [Subjects and Methods] The dominant shoulders of 27 healthy subjects were examined. Electromagnetic sensors attached to the scapula, thorax, and humerus were used to determine three-dimensional scapular kinematics during active arm elevation with or without external loads and passive arm elevation. Simultaneously, the activities of seven shoulder muscles were recorded with surface and intramuscular fine-wire electrodes. [Results] Compared with active arm elevation, passive elevation between 30° and 100° significantly decreased the scapular upward rotation and increased the glenohumeral elevation angle. However, no significant differences in scapular posterior tilt and external rotation were observed between active and passive arm elevation, and scapular plane kinematics were not affected by muscle activity. [Conclusion] Unlike active motion with or without an external load, passive arm elevation significantly decreased the scapular upward rotation and significantly increased the mid-range glenohumeral elevation. These data, which suggest that passive arm elevation should be avoided during the early postoperative period, may expand the understanding of rehabilitation after arthroscopic rotator cuff repair. PMID:27390438

  19. SMAP and SMOS soil moisture validation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The SMOS and SMAP satellite missions each produce global soil moisture products using L-band radiometry. Both missions begin with the same fundamental equations in developing their soil moisture retrieval algorithm but implement it differently due to design differences of the instruments. SMOS with ...

  20. Detecting soil moisture pulses and associated vegetation response in a southern Arizona watershed using SMAP and MODIS

    NASA Astrophysics Data System (ADS)

    Barnes, M.; Moran, M. S.; Scott, R. L.

    2015-12-01

    In arid and semiarid ecosystems, rainfall pulses and associated vegetation responses play a crucial role in ecosystem and hydrologic functioning. While rainfall pulses are generally correlated with increased photosynthetic activity, the effect of these rainfall pulses in the context of persistent drought is unclear. Rainfall events during drought can lead to an overall reduction in primary productivity due to reduced soil infiltration and increased erosion. To assess the effective rainfall available for initiating biological processes, measurements of soil moisture are necessary. Rainfall pulses in drylands are generally localized in time and space making them difficult to detect remotely. Our objective was to determine whether space-based observations of soil moisture have the necessary spatial and temporal resolution to detect soil moisture pulses resulting from rain events in the Walnut Gulch Experimental Watershed (WGEW) in southern Arizona. Using pre-beta-release soil moisture observations from the newly launched NASA Soil Moisture Active Passive (SMAP) observatory, we examined the effects of rainfall pulses on soil moisture over the Walnut Gulch Experimental Watershed from April to July 2015. To assess whether soil moisture pulses were associated with increased vegetation production, we monitored increases in vegetation greenness using the NASA MODIS Enhanced Vegetation Index (EVI) following increases in soil moisture. Regional-scale results were supported with local-scale in situ measurements of soil moisture, vegetation greenness from phenocams, precipitation and Net Ecosystem Exchange (NEE) associated with two eddy covariance flux towers at WGEW. In conclusion, SMAP observations have the potential to detect large rainfall pulses at the 9 km resolution, and the associated soil moisture pulses can result in increased EVI at the watershed scale. These results contribute to our understanding of the ecosystem and hydrologic functioning of dryland ecosystems.

  1. The Sandia MEMS passive shock sensor : FY07 maturation activities.

    SciTech Connect

    Houston, Jack E.; Blecke, Jill; Mitchell, John Anthony; Wittwer, Jonathan W.; Crowson, Douglas A.; Clemens, Rebecca C.; Walraven, Jeremy Allen; Epp, David S.; Baker, Michael Sean

    2008-08-01

    This report describes activities conducted in FY07 to mature the MEMS passive shock sensor. The first chapter of the report provides motivation and background on activities that are described in detail in later chapters. The second chapter discusses concepts that are important for integrating the MEMS passive shock sensor into a system. Following these two introductory chapters, the report details modeling and design efforts, packaging, failure analysis and testing and validation. At the end of FY07, the MEMS passive shock sensor was at TRL 4.

  2. Solar air-conditioning-active, hybrid and passive

    SciTech Connect

    Yellott, J. I.

    1981-04-01

    After a discussion of summer air conditioning requirements in the United States, active, hybrid, and passive cooling systems are defined. Active processes and systems include absorption, Rankine cycle, and a small variety of miscellaneous systems. The hybrid solar cooling and dehumidification technology of desiccation is covered as well as evaporative cooling. The passive solar cooling processes covered include convective, radiative and evaporative cooling. Federal and state involvement in solar cooling is then discussed. (LEW)

  3. Soil Moisture Active Passive Mission L4_SM Data Product Assessment (Version 2 Validated Release)

    NASA Technical Reports Server (NTRS)

    Reichle, Rolf Helmut; De Lannoy, Gabrielle J. M.; Liu, Qing; Ardizzone, Joseph V.; Chen, Fan; Colliander, Andreas; Conaty, Austin; Crow, Wade; Jackson, Thomas; Kimball, John; Koster, Randal D.; Smith, E. Brent

    2016-01-01

    During the post-launch SMAP calibration and validation (Cal/Val) phase there are two objectives for each science data product team: 1) calibrate, verify, and improve the performance of the science algorithm, and 2) validate the accuracy of the science data product as specified in the science requirements and according to the Cal/Val schedule. This report provides an assessment of the SMAP Level 4 Surface and Root Zone Soil Moisture Passive (L4_SM) product specifically for the product's public Version 2 validated release scheduled for 29 April 2016. The assessment of the Version 2 L4_SM data product includes comparisons of SMAP L4_SM soil moisture estimates with in situ soil moisture observations from core validation sites and sparse networks. The assessment further includes a global evaluation of the internal diagnostics from the ensemble-based data assimilation system that is used to generate the L4_SM product. This evaluation focuses on the statistics of the observation-minus-forecast (O-F) residuals and the analysis increments. Together, the core validation site comparisons and the statistics of the assimilation diagnostics are considered primary validation methodologies for the L4_SM product. Comparisons against in situ measurements from regional-scale sparse networks are considered a secondary validation methodology because such in situ measurements are subject to up-scaling errors from the point-scale to the grid cell scale of the data product. Based on the limited set of core validation sites, the wide geographic range of the sparse network sites, and the global assessment of the assimilation diagnostics, the assessment presented here meets the criteria established by the Committee on Earth Observing Satellites for Stage 2 validation and supports the validated release of the data. An analysis of the time average surface and root zone soil moisture shows that the global pattern of arid and humid regions are captured by the L4_SM estimates. Results from the

  4. The relationships between active extensibility, and passive and active stiffness of the knee flexors.

    PubMed

    Blackburn, J Troy; Padua, Darin A; Riemann, Bryan L; Guskiewicz, Kevin M

    2004-12-01

    Insufficient active knee flexor stiffness may predispose the anterior cruciate ligament to injury. Insufficient passive stiffness may result in insufficient active stiffness. Similarly, higher levels of musculotendinous extensibility may inhibit active and passive muscle stiffness, potentially contributing to an increased risk of injury. The literature is both limited and inconsistent concerning relationships between extensibility, passive stiffness, and active stiffness. Extensibility was measured as the maximal active knee extension angle from a supine position with the hip flexed to 90 degrees . Passive stiffness was calculated as the slope of the moment-angle curve resulting from passive knee extension. Active stiffness was assessed via acceleration associated with damped oscillatory motion about the knee. Stepwise multiple regression indicated that passive stiffness accounted for 25% of active muscle stiffness variance. The linear combination of extensibility and passive stiffness explained only 2% more variance compared to passive stiffness alone. Musculotendinous extensibility was moderately related to passive muscle stiffness, and weakly related to active muscle stiffness. The moderate relationship observed between active and passive stiffness emphasizes the dependence of active muscle stiffness on cross-bridge formation, and the relatively smaller contribution from parallel elastic tissues. Additionally, heightened extensibility does not appear to be a predisposing factor for reduced muscle stiffness. PMID:15491843

  5. Satellite Remote Sensing of Net Ecosystem CO2 Exchange Using Optical-IR and Microwave Sensors: Algorithm Development for the SMAP Decadal Survey Mission

    NASA Astrophysics Data System (ADS)

    Jones, L. A.; Kimball, J. S.; Reichle, R. H.; Zhang, K.; McDonald, K. C.

    2009-12-01

    The global balance between photosynthesis, respiration, and disturbance determines whether ecosystems will continue to offset human CO2 emissions. Changes in temperature and moisture constraints can differentially affect photosynthesis and respiration, whereas disturbance and stand succession can push ecosystems far from steady state, shifting carbon source-sink dynamics. Remote sensing and ecosystem process model simulations allow us to characterize the climatic sensitivity of this balance, but effective model parameters are uncertain at continental scales. We developed a carbon model to derive daily net ecosystem exchange of CO2 (NEE) using MODIS GPP and surface soil moisture and temperature retrievals from AMSR-E as driving data. We apply Bayesian synthesis to parameterize the model with a range of FLUXNET tower CO2 measurements across representative global biomes, while accounting for error in flux observations, driving data, and model structure. Model fit diagnostics are compared to determine the relative value of remotely sensed information for accurate prediction of carbon fluxes. Model parameters vary with ecosystem type and indicate that most ecosystems have not reached soil organic carbon pools expected for steady state. Model fit is relatively more impacted by MODIS GPP than by AMSR-E temperature and moisture. AMSR-E moisture explains arid region fluxes, whereas temperature is a stronger predictor for high-latitude locations. The results of this study offer a benchmark for calibrating and assessing the incremental value of Soil Moisture Active Passive (SMAP) mission observations over information available from existing sensors. The Soil Moisture Active Passive (SMAP) mission with scheduled 2013 launch date will provide moderate resolution soil moisture (10 km) and freeze-thaw state (1-3 km) information potentially providing new estimates of land surface processes, including daily NEE. This work was performed at The University of Montana and Jet

  6. Hybrid Active/Passive Jet Engine Noise Suppression System

    NASA Technical Reports Server (NTRS)

    Parente, C. A.; Arcas, N.; Walker, B. E.; Hersh, A. S.; Rice, E. J.

    1999-01-01

    A novel adaptive segmented liner concept has been developed that employs active control elements to modify the in-duct sound field to enhance the tone-suppressing performance of passive liner elements. This could potentially allow engine designs that inherently produce more tone noise but less broadband noise, or could allow passive liner designs to more optimally address high frequency broadband noise. A proof-of-concept validation program was undertaken, consisting of the development of an adaptive segmented liner that would maximize attenuation of two radial modes in a circular or annular duct. The liner consisted of a leading active segment with dual annuli of axially spaced active Helmholtz resonators, followed by an optimized passive liner and then an array of sensing microphones. Three successively complex versions of the adaptive liner were constructed and their performances tested relative to the performance of optimized uniform passive and segmented passive liners. The salient results of the tests were: The adaptive segmented liner performed well in a high flow speed model fan inlet environment, was successfully scaled to a high sound frequency and successfully attenuated three radial modes using sensor and active resonator arrays that were designed for a two mode, lower frequency environment.

  7. Passive and active tension in single cardiac myofibrils.

    PubMed Central

    Linke, W A; Popov, V I; Pollack, G H

    1994-01-01

    Single myofibrils were isolated from chemically skinned rabbit heart and mounted in an apparatus described previously (Fearn et al., 1993; Linke et al., 1993). We measured the passive length-tension relation and active isometric force, both normalized to cross sectional area. Myofibrillar cross sectional area was calculated based on measurements of myofibril diameter from both phase-contrast images and electron micrographs. Passive tension values up to sarcomere lengths of approximately 2.2 microns were similar to those reported in larger cardiac muscle specimens. Thus, the element responsible for most, if not all, passive force of cardiac muscle at physiological sarcomere lengths appears to reside within the myofibrils. Above 2.2 microns, passive tension continued to rise, but not as steeply as reported in multicellular preparations. Apparently, structures other than the myofibrils become increasingly important in determining the magnitude of passive tension at these stretched lengths. Knowing the myofibrillar component of passive tension allowed us to infer the stress-strain relation of titin, the polypeptide thought to support passive force in the sarcomere. The elastic modulus of titin is 3.5 x 10(6) dyn cm-2, a value similar to that reported for elastin. Maximum active isometric tension in the single myofibril at sarcomere lengths of 2.1-2.3 microns was 145 +/- 35 mN/mm2 (mean +/- SD; n = 15). This value is comparable with that measured in fixed-end contractions of larger cardiac specimens, when the amount of nonmyofibrillar space in those preparations is considered. However, it is about 4 times lower than the maximum active tension previously measured in single skeletal myofibrils under similar conditions (Bartoo et al., 1993). Images FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 7 PMID:7948691

  8. 26 CFR 1.469-3T - Passive activity credit (temporary).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 6 2014-04-01 2014-04-01 false Passive activity credit (temporary). 1.469-3T... TAX (CONTINUED) INCOME TAXES (CONTINUED) Taxable Year for Which Deductions Taken § 1.469-3T Passive activity credit (temporary). (a) Computation of passive activity credit. The taxpayer's passive...

  9. 26 CFR 1.469-3T - Passive activity credit (temporary).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 6 2012-04-01 2012-04-01 false Passive activity credit (temporary). 1.469-3T... TAX (CONTINUED) INCOME TAXES (CONTINUED) Taxable Year for Which Deductions Taken § 1.469-3T Passive activity credit (temporary). (a) Computation of passive activity credit. The taxpayer's passive...

  10. 26 CFR 1.469-3T - Passive activity credit (temporary).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 6 2013-04-01 2013-04-01 false Passive activity credit (temporary). 1.469-3T... TAX (CONTINUED) INCOME TAXES (CONTINUED) Taxable Year for Which Deductions Taken § 1.469-3T Passive activity credit (temporary). (a) Computation of passive activity credit. The taxpayer's passive...

  11. Separating active and passive influences on stomatal control of transpiration.

    PubMed

    McAdam, Scott A M; Brodribb, Timothy J

    2014-04-01

    Motivated by studies suggesting that the stomata of ferns and lycophytes do not conform to the standard active abscisic acid (ABA) -mediated stomatal control model, we examined stomatal behavior in a conifer species (Metasequoia glyptostroboides) that is phylogenetically midway between the fern and angiosperm clades. Similar to ferns, daytime stomatal closure in response to moderate water stress seemed to be a passive hydraulic process in M. glyptostroboides immediately alleviated by rehydrating excised shoots. Only after prolonged exposure to more extreme water stress did active ABA-mediated stomatal closure become important, because foliar ABA production was triggered after leaf turgor loss. The influence of foliar ABA on stomatal conductance and stomatal aperture was highly predictable and additive with the passive hydraulic influence. M. glyptostroboides thus occupies a stomatal behavior type intermediate between the passively controlled ferns and the characteristic ABA-dependent stomatal closure described in angiosperm herbs. These results highlight the importance of considering phylogeny as a major determinant of stomatal behavior.

  12. Active and Passive Perceptual Learning in the Visually Impaired.

    ERIC Educational Resources Information Center

    Conrod, Beverley E.; And Others

    1986-01-01

    Active and passive perceptual training methods were tested with 30 macular degeneration patients to improve their residual vision. The main conclusion was that perceptual training may contribute to successful visual adjustment and that the effect of training is not limited to a particular level of visual impairment. (Author/CL)

  13. 77 FR 15003 - Passive Activity Losses and Credits Limited; Hearing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-14

    ... Internal Revenue Service 26 CFR Part 1 RIN 1545-BJ33 Passive Activity Losses and Credits Limited; Hearing AGENCY: Internal Revenue Service (IRS), Treasury. ] ACTION: Notice of public hearing on proposed rulemaking. SUMMARY: This document provides notice of public hearing on proposed rulemaking regarding...

  14. Active and passive noise control using electroactive polymer actuators (EAPAs)

    NASA Astrophysics Data System (ADS)

    Ramanathan, Kartik; Zhu, Bei; Chang, Woosuk; Varadan, Vasundara V.; Varadan, Vijay K.

    1999-06-01

    Electro-active polymer actuators (EAPA) have been a topic of research interest in the recent decades due to their ability to produce large strains under the influence of relatively low electric fields as compared to commercially available actuators. This paper investigates the feasibility of EAPA for active and passive cabin noise control. The passive damping characteristics of EAPA were determined, by measuring the transmission loss of four samples of various thickness and composition in an anechoic chamber in the 200 - 2000 Hz frequency range. This was then compared to that of Plexiglas and silicone rubber sheets of comparable thickness. The transmission loss of EAPA and Plexiglas were observed to be about the same. The transmission loss of EAPA was greater than that of silicone rubber, of the same thickness. The experimental and theoretical results computed using the mass law agree well. EAPA produces a strain of 0.006 for an applied field of 1 V/m. The ability of EAPA to potentially provide active as well as passive damping in the low to intermediate frequency range, along with being light- weight, pliable and transparent, makes it attractive for noise control applications as active/passive windows or wall papers.

  15. Enhanced Passive and Active Processing of Syllables in Musician Children

    ERIC Educational Resources Information Center

    Chobert, Julie; Marie, Celine; Francois, Clement; Schon, Daniele; Besson, Mireille

    2011-01-01

    The aim of this study was to examine the influence of musical expertise in 9-year-old children on passive (as reflected by MMN) and active (as reflected by discrimination accuracy) processing of speech sounds. Musician and nonmusician children were presented with a sequence of syllables that included standards and deviants in vowel frequency,…

  16. Passive and Active Sensing Technologies for Structural Health Monitoring

    NASA Astrophysics Data System (ADS)

    Do, Richard

    A combination of passive and active sensing technologies is proposed as a structural health monitoring solution for several applications. Passive sensing is differentiated from active sensing in that with the former, no energy is intentionally imparted into the structure under test; sensors are deployed in a pure detection mode for collecting data mined for structural health monitoring purposes. In this thesis, passive sensing using embedded fiber Bragg grating optical strain gages was used to detect varying degrees of impact damage using two different classes of features drawn from traditional spectral analysis and auto-regressive time series modeling. The two feature classes were compared in detail through receiver operating curve performance analysis. The passive detection problem was then augmented with an active sensing system using ultrasonic guided waves (UGWs). This thesis considered two main challenges associated with UGW SHM including in-situ wave propagation property determination and thermal corruption of data. Regarding determination of wave propagation properties, of which dispersion characteristics are the most important, a new dispersion curve extraction method called sparse wavenumber analysis (SWA) was experimentally validated. Also, because UGWs are extremely sensitive to ambient temperature changes on the structure, it significantly affects the wave propagation properties by causing large errors in the residual error in the processing of the UGWs from an array. This thesis presented a novel method that compensates for uniform temperature change by considering the magnitude and phase of the signal separately and applying a scalable transformation.

  17. Comparative evaluation of passive, active, and passive-active distraction techniques on pain perception during local anesthesia administration in children.

    PubMed

    Abdelmoniem, Soad A; Mahmoud, Sara A

    2016-05-01

    Local anesthesia forms the backbone of pain control techniques and is necessary for a painless dental procedure. Nevertheless, administering a local anesthetic injection is among the most anxiety-provoking procedures to children. This study was performed to compare the efficacy of different distraction techniques (passive, active, and passive-active) on children's pain perception during local anesthesia administration. A total of 90 children aged four to nine years, requiring inferior alveolar nerve block for primary molar extraction, were included in this study and randomly divided into three groups according to the distraction technique employed during local anesthesia administration. Passive distraction group: the children were instructed to listen to a song on headphones; Active distraction group: the children were instructed to move their legs up and down alternatively; and Passive-active distraction group: this was a combination between both techniques. Pain perception during local anesthesia administration was evaluated by the Sounds, Eyes, and Motor (SEM) scale and Wong Baker FACES® Pain Rating Scale. There was an insignificant difference between the three groups for SEM scale and Wong Baker FACES Pain Rating Scale at P = 0.743 and P = 0.112 respectively. The examined distraction techniques showed comparable results in reducing pain perception during local anesthesia administration.

  18. 26 CFR 1.1398-1 - Treatment of passive activity losses and passive activity credits in individuals' title 11 cases.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 11 2011-04-01 2011-04-01 false Treatment of passive activity losses and..., 1992. This section applies to cases commencing on or after November 9, 1992. (2) Cases commencing before November 9, 1992—(i) Election required. This section applies to a case commencing before...

  19. 26 CFR 1.1398-1 - Treatment of passive activity losses and passive activity credits in individuals' title 11 cases.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 11 2013-04-01 2013-04-01 false Treatment of passive activity losses and..., 1992. This section applies to cases commencing on or after November 9, 1992. (2) Cases commencing before November 9, 1992—(i) Election required. This section applies to a case commencing before...

  20. Comparative evaluation of passive, active, and passive-active distraction techniques on pain perception during local anesthesia administration in children

    PubMed Central

    Abdelmoniem, Soad A.; Mahmoud, Sara A.

    2015-01-01

    Local anesthesia forms the backbone of pain control techniques and is necessary for a painless dental procedure. Nevertheless, administering a local anesthetic injection is among the most anxiety-provoking procedures to children. This study was performed to compare the efficacy of different distraction techniques (passive, active, and passive-active) on children’s pain perception during local anesthesia administration. A total of 90 children aged four to nine years, requiring inferior alveolar nerve block for primary molar extraction, were included in this study and randomly divided into three groups according to the distraction technique employed during local anesthesia administration. Passive distraction group: the children were instructed to listen to a song on headphones; Active distraction group: the children were instructed to move their legs up and down alternatively; and Passive-active distraction group: this was a combination between both techniques. Pain perception during local anesthesia administration was evaluated by the Sounds, Eyes, and Motor (SEM) scale and Wong Baker FACES® Pain Rating Scale. There was an insignificant difference between the three groups for SEM scale and Wong Baker FACES Pain Rating Scale at P = 0.743 and P = 0.112 respectively. The examined distraction techniques showed comparable results in reducing pain perception during local anesthesia administration. PMID:27222759

  1. Diffusion of passive particles in active suspensions

    NASA Astrophysics Data System (ADS)

    Mussler, Matthias; Rafai, Salima; John, Thomas; Peyla, Philippe; Wagner, Christian

    2013-11-01

    We study how an active suspension consisting of a definite volume fraction of the microswimmer Chlamydomonas Reinhardtii modifies the Brownian movement of small to medium size microspheres. We present measurements and simulations of trajectories of microspheres with a diameter of 20 μm in suspensions of Chlamydomonas Reinhardtii, a so called ``puller,'' and show that the mean squared displacement of such trajectories consist of parabolic and a linear part. The linear part is due to the hydrodynamic noise of the microswimmers while the parabolic part is a consequence of directed motion events that occur randomly, when a microsphere is transported by a microswimmer on a timescale that is in higher order of magnitude than the Brownian like hydrodynamic interaction. In addition, we theoretically describe this effect with a dimensional analysis that takes the force dipole model used to describe ``puller'' like Chlamydomonas Reinhardtii into account.

  2. Active and Passive Smoking and Fecundability in Danish Pregnancy Planners

    PubMed Central

    Radin, Rose G.; Hatch, Elizabeth E.; Rothman, Kenneth J.; Mikkelsen, Ellen M.; Sørensen, Henrik Toft; Riis, Anders H.; Wise, Lauren A.

    2014-01-01

    Objective To investigate the extent to which fecundability is associated with active smoking, time since smoking cessation, and passive smoking. Design Prospective cohort study. Setting Denmark, 2007–2011. Patients 3,773 female pregnancy planners aged 18–40 years. Intervention None. Main Outcome Measures Self-reported pregnancy. Fecundability ratios (FR) and 95% confidence intervals (CI) were estimated using a proportional probabilities model that adjusted for menstrual cycle at risk and potential confounders. Results Among current smokers, smoking duration ≥10 years was associated with reduced fecundability compared with never smokers (FR=0.85, 95% CI: 0.72–1.00). Former smokers who had smoked ≥10 pack-years had reduced fecundability regardless of when they quit smoking (1–1.9 years FR=0.83, 95% CI: 0.54–1.27; ≥2 years FR=0.73, 95% CI: 0.53–1.02). Among never smokers, the FRs were 1.04 (95% CI: 0.89–1.21) for passive smoking in early life and 0.92 (95% CI: 0.82–1.03) for passive smoking in adulthood. Conclusions Among Danish pregnancy planners, cumulative exposure to active cigarette smoking was associated with delayed conception among current and former smokers. Time since smoking cessation and passive smoking were not appreciably associated with fecundability. PMID:24746741

  3. Active and passive stabilization of body pitch in insect flight

    PubMed Central

    Ristroph, Leif; Ristroph, Gunnar; Morozova, Svetlana; Bergou, Attila J.; Chang, Song; Guckenheimer, John; Wang, Z. Jane; Cohen, Itai

    2013-01-01

    Flying insects have evolved sophisticated sensory–motor systems, and here we argue that such systems are used to keep upright against intrinsic flight instabilities. We describe a theory that predicts the instability growth rate in body pitch from flapping-wing aerodynamics and reveals two ways of achieving balanced flight: active control with sufficiently rapid reactions and passive stabilization with high body drag. By glueing magnets to fruit flies and perturbing their flight using magnetic impulses, we show that these insects employ active control that is indeed fast relative to the instability. Moreover, we find that fruit flies with their control sensors disabled can keep upright if high-drag fibres are also attached to their bodies, an observation consistent with our prediction for the passive stability condition. Finally, we extend this framework to unify the control strategies used by hovering animals and also furnish criteria for achieving pitch stability in flapping-wing robots. PMID:23697713

  4. Active and passive calcium transport systems in plant cells

    SciTech Connect

    Sze, H.

    1990-01-01

    The ability to change cytoplasmic Ca{sup 2+} levels ((Ca{sup 2+})) by cells has made this cation a key regulator of many biological processes. Cytoplasmic (Ca{sup 2+}) is determined by the coordination of passive Ca{sup 2+} fluxes which increase cytosolic (Ca{sup 2+}) and active Ca{sup 2+} transport systems that lower cytosolic (Ca{sup 2+}). The mechanisms by which plant cells achieve this is poorly understood. We have initially used isolated vesicles from the plasma membrane or organellar membranes to study Ca{sup 2+} transport systems in oat roots (a monocot) and carrot suspension cells (a dicot). The objectives of the proposal were to identify and characterize active (energy-dependent) and passive calcium transport systems that work together to regulate calcium levels in the cytoplasm of plant cells. 10 figs., 2 tabs.

  5. Active and passive stabilization of body pitch in insect flight.

    PubMed

    Ristroph, Leif; Ristroph, Gunnar; Morozova, Svetlana; Bergou, Attila J; Chang, Song; Guckenheimer, John; Wang, Z Jane; Cohen, Itai

    2013-08-01

    Flying insects have evolved sophisticated sensory-motor systems, and here we argue that such systems are used to keep upright against intrinsic flight instabilities. We describe a theory that predicts the instability growth rate in body pitch from flapping-wing aerodynamics and reveals two ways of achieving balanced flight: active control with sufficiently rapid reactions and passive stabilization with high body drag. By glueing magnets to fruit flies and perturbing their flight using magnetic impulses, we show that these insects employ active control that is indeed fast relative to the instability. Moreover, we find that fruit flies with their control sensors disabled can keep upright if high-drag fibres are also attached to their bodies, an observation consistent with our prediction for the passive stability condition. Finally, we extend this framework to unify the control strategies used by hovering animals and also furnish criteria for achieving pitch stability in flapping-wing robots.

  6. Eye movements and hazard perception in active and passive driving

    PubMed Central

    Mackenzie, Andrew K.; Harris, Julie M.

    2015-01-01

    ABSTRACT Differences in eye movement patterns are often found when comparing passive viewing paradigms to actively engaging in everyday tasks. Arguably, investigations into visuomotor control should therefore be most useful when conducted in settings that incorporate the intrinsic link between vision and action. We present a study that compares oculomotor behaviour and hazard reaction times across a simulated driving task and a comparable, but passive, video-based hazard perception task. We found that participants scanned the road less during the active driving task and fixated closer to the front of the vehicle. Participants were also slower to detect the hazards in the driving task. Our results suggest that the interactivity of simulated driving places increased demand upon the visual and attention systems than simply viewing driving movies. We offer insights into why these differences occur and explore the possible implications of such findings within the wider context of driver training and assessment. PMID:26681913

  7. Phase Segregation of Passive Advective Particles in an Active Medium

    NASA Astrophysics Data System (ADS)

    Das, Amit; Polley, Anirban; Rao, Madan

    2016-02-01

    Localized contractile configurations or asters spontaneously appear and disappear as emergent structures in the collective stochastic dynamics of active polar actomyosin filaments. Passive particles which (un)bind to the active filaments get advected into the asters, forming transient clusters. We study the phase segregation of such passive advective scalars in a medium of dynamic asters, as a function of the aster density and the ratio of the rates of aster remodeling to particle diffusion. The dynamics of coarsening shows a violation of Porod behavior; the growing domains have diffuse interfaces and low interfacial tension. The phase-segregated steady state shows strong macroscopic fluctuations characterized by multiscaling and intermittency, signifying rapid reorganization of macroscopic structures. We expect these unique nonequilibrium features to manifest in the actin-dependent molecular clustering at the cell surface.

  8. Active and passive stabilization of body pitch in insect flight.

    PubMed

    Ristroph, Leif; Ristroph, Gunnar; Morozova, Svetlana; Bergou, Attila J; Chang, Song; Guckenheimer, John; Wang, Z Jane; Cohen, Itai

    2013-08-01

    Flying insects have evolved sophisticated sensory-motor systems, and here we argue that such systems are used to keep upright against intrinsic flight instabilities. We describe a theory that predicts the instability growth rate in body pitch from flapping-wing aerodynamics and reveals two ways of achieving balanced flight: active control with sufficiently rapid reactions and passive stabilization with high body drag. By glueing magnets to fruit flies and perturbing their flight using magnetic impulses, we show that these insects employ active control that is indeed fast relative to the instability. Moreover, we find that fruit flies with their control sensors disabled can keep upright if high-drag fibres are also attached to their bodies, an observation consistent with our prediction for the passive stability condition. Finally, we extend this framework to unify the control strategies used by hovering animals and also furnish criteria for achieving pitch stability in flapping-wing robots. PMID:23697713

  9. Passive and active adaptive management: Approaches and an example

    USGS Publications Warehouse

    Williams, B.K.

    2011-01-01

    Adaptive management is a framework for resource conservation that promotes iterative learning-based decision making. Yet there remains considerable confusion about what adaptive management entails, and how to actually make resource decisions adaptively. A key but somewhat ambiguous distinction in adaptive management is between active and passive forms of adaptive decision making. The objective of this paper is to illustrate some approaches to active and passive adaptive management with a simple example involving the drawdown of water impoundments on a wildlife refuge. The approaches are illustrated for the drawdown example, and contrasted in terms of objectives, costs, and potential learning rates. Some key challenges to the actual practice of AM are discussed, and tradeoffs between implementation costs and long-term benefits are highlighted. ?? 2010 Elsevier Ltd.

  10. The terminal quality of life and passive or active euthanasia.

    PubMed

    Daikos, G K

    1990-01-01

    The problems presented by the different categories of dying people are briefly discussed from the point of view of terminal quality of life. Euthanasia is used in its broader meaning, including both passive and active aspects. Passive euthanasia (PE) is exercised by withholding advanced or basic life support measures, the commonest form being do not resuscitate orders (DNR). Some data on its application are presented. Active euthanasia (AE), which has been proposed and being applied to a limited extent lately, is criticized as leading the physician and the Society onto risky ground. A position is being taken against it. Decision making, examples of guidelines, legal, philosophical and spiritual considerations are discussed. Wisdom and loving care should be exercised by the physician to assist people in their terminal phases and to alleviate their suffering. That there is not a single answer to the problem is discussed.

  11. Active and passive calcium transport systems in plant cells

    SciTech Connect

    Sze, H.

    1991-01-01

    The ability to change cytoplasmic Ca{sup 2+} levels ((Ca{sup 2+})) by cells has made this cation a key regulator of many biological processes. Cytoplasmic (Ca{sup 2+}) is determined by the coordination of passive Ca{sup 2+} fluxes which increase cytosolic (Ca{sup 2+}) and active Ca{sup 2+} transport systems that lower cytosolic (Ca{sup 2+}). The mechanisms by which plant cells achieve this is poorly understood. We have initially used isolated vesicles from the plasma membrane or organellar membranes to study Ca{sup 2+} transport systems in oat roots (a monocot) and carrot suspension cells (a dicot). The objectives of the proposal were to identify and characterize active (energy-dependent) and passive calcium transport systems that work together to regulate calcium levels in the cytoplasm of plant cells.

  12. Passive and active structural monitoring experience: Civil engineering applications

    NASA Astrophysics Data System (ADS)

    Thompson, L. D.; Westermo, B. D.; Crum, D. B.; Law, W. R.; Trombi, R. G.

    2000-05-01

    State Departments of Transportation and regional city government officials are beginning to view the long-term monitoring of infrastructure as being beneficial for structural damage accumulation assessment, condition based maintenance, life extension, and post-earthquake or -hurricane (-tornado, -typhoon, etc.) damage assessment. Active and passive structural monitoring systems were installed over the last few years to monitor concerns in a wide range of civil infrastructure applications. This paper describes the monitoring technologies and systems employed for such applications. Bridge system applications were directed at monitoring corrosion damage accumulation, composite reinforcements for life extension, general service cracking damage related to fatigue and overloads, and post-earthquake damage. Residential system applications were directed primarily at identifying damage accumulation and post-earthquake damage assessment. A professional sports stadium was monitored for isolated ground instability problems and for post-earthquake damage assessment. Internet-based, remote, data acquisition system experience is discussed with examples of long-term passive and active system data collected from many of the individual sites to illustrate the potential for both passive and active structural health monitoring. A summary of system-based operating characteristics and key engineering recommendations are provided to achieve specific structural monitoring objectives for a wide range of civil infrastructure applications.

  13. Active and passive computed tomography for nondestructive assay

    SciTech Connect

    Bernardi, R T; Camp, D E; Clard, D; Jackson, J A; Martz, H E, Decman, D J; Roberson, G P

    1998-10-28

    Traditional gamma-ray methods used to characterize nuclear waste introduce errors that are related to non-uniform measurement responses associated with unknown radioactive source and matrix material distributions. These errors can be reduced by applying an active and passive tomographic technique (A&PCT) developed at the Lawrence Livermore National Laboratory (LLNL). The technique uses an external radioactive source and active tomography to map the attenuation within a waste barrel as a function of mono-energetic gamma-ray energy. Passive tomography is used to localize and identify specific radioactive waste within the same container. Reconstruction of the passive data using the attenuation maps at specific energies allows internal waste radioactivity to be corrected for any overlying heterogeneous materials, thus yielding an absolute assay of the waste activity. LLNL and Bio-Imaging Research, Inc. have collaborated in a technology transfer effort to integrate an A&PCT assay system into a mobile waste characterization trailer. This mobile system has participated in and passed several formal DOE-sponsored performance demonstrations, tests and evaluations. The system is currently being upgraded with multiple detectors to improve throughput, automated gamma-ray analysis code to simplify the assay, and a new emission reconstruction code to improve accuracy

  14. Assimilation of Passive and Active Microwave Soil Moisture Retrievals

    NASA Technical Reports Server (NTRS)

    Draper, C. S.; Reichle, R. H.; DeLannoy, G. J. M.; Liu, Q.

    2012-01-01

    Root-zone soil moisture is an important control over the partition of land surface energy and moisture, and the assimilation of remotely sensed near-surface soil moisture has been shown to improve model profile soil moisture [1]. To date, efforts to assimilate remotely sensed near-surface soil moisture at large scales have focused on soil moisture derived from the passive microwave Advanced Microwave Scanning Radiometer (AMSR-E) and the active Advanced Scatterometer (ASCAT; together with its predecessor on the European Remote Sensing satellites (ERS. The assimilation of passive and active microwave soil moisture observations has not yet been directly compared, and so this study compares the impact of assimilating ASCAT and AMSR-E soil moisture data, both separately and together. Since the soil moisture retrieval skill from active and passive microwave data is thought to differ according to surface characteristics [2], the impact of each assimilation on the model soil moisture skill is assessed according to land cover type, by comparison to in situ soil moisture observations.

  15. Assimilation of Synchronous and Asynchronous Active/Passive Microwave Observations at Different Spatial Scales for Improved Soil Moisture and Crop Growth

    NASA Astrophysics Data System (ADS)

    Judge, J.; Liu, P. W.; Monsivais-Huertero, A.; Steele-Dunne, S. C.; Bongiovanni, T. E.; Bindlish, R.; Jackson, T. J.

    2014-12-01

    Assimilation of active and passive (AP) microwave observations at L-band in the crop simulation models is able to improve estimates of soil moisture (SM) and crop growth in the models. These observations provide complementary information for dynamic heterogeneous landscapes. Active observations are more sensitive to soil surface roughness and vegetation structure, while passive observations are more sensitive to SM. These observations may be available at different spatial and temporal resolutions from different satellite platforms. For example, the present ESA Soil Moisture Ocean Salinity (SMOS) mission provides passive observations at 1.41 GHz at 25 km every 2-3 days, while the NASA/CONAE Aquarius mission provides L-band AP observations at spatial resolution of 150 km with a repeat coverage of 7 days for global SM products. The planned NASA Soil Moisture Active Passive mission (SMAP) will provide AP observations at 1.26 and 1.41 GHz at the spatial resolutions of 3 and 30 km, respectively, with a repeat coverage of 2-3 days, starting early 2015. The goal of this study is to develop an Ensemble Kalman Filter-based methodology that assimilates synchronously and asynchronously available backscattering coefficients (σ0) and brightness temperatures (TB) at different spatial scales from SMOS and Aquarius. The Decision Support System for Agrotechnology Transfer (DSSAT) that contains a suite of crop simulation models will be linked to microwave emission and scattering models (DSSAT-A-P) for the assimilation. The methodology will be implemented in the rain fed agricultural region of the Brazilian La Plata Basin in South America, where soybean is the primary crop. The augmented state vector will include both model states and parameters related to soil and vegetation during the growing season. The methodology will be evaluated using a synthetic experiment and also using observations from SMOS and Aquarius. In preliminary results with synthetic experiment, using asynchronous

  16. AMISS - Active and passive MIcrowaves for Security and Subsurface imaging

    NASA Astrophysics Data System (ADS)

    Soldovieri, Francesco; Slob, Evert; Turk, Ahmet Serdar; Crocco, Lorenzo; Catapano, Ilaria; Di Matteo, Francesca

    2013-04-01

    The FP7-IRSES project AMISS - Active and passive MIcrowaves for Security and Subsurface imaging is based on a well-combined network among research institutions of EU, Associate and Third Countries (National Research Council of Italy - Italy, Technische Universiteit Delft - The Netherlands, Yildiz Technical University - Turkey, Bauman Moscow State Technical University - Russia, Usikov Institute for Radio-physics and Electronics and State Research Centre of Superconductive Radioelectronics "Iceberg" - Ukraine and University of Sao Paulo - Brazil) with the aims of achieving scientific advances in the framework of microwave and millimeter imaging systems and techniques for security and safety social issues. In particular, the involved partners are leaders in the scientific areas of passive and active imaging and are sharing their complementary knowledge to address two main research lines. The first one regards the design, characterization and performance evaluation of new passive and active microwave devices, sensors and measurement set-ups able to mitigate clutter and increase information content. The second line faces the requirements to make State-of-the-Art processing tools compliant with the instrumentations developed in the first line, suitable to work in electromagnetically complex scenarios and able to exploit the unexplored possibilities offered by new instrumentations. The main goals of the project are: 1) Development/improvement and characterization of new sensors and systems for active and passive microwave imaging; 2) Set up, analysis and validation of state of art/novel data processing approach for GPR in critical infrastructure and subsurface imaging; 3) Integration of state of art and novel imaging hardware and characterization approaches to tackle realistic situations in security, safety and subsurface prospecting applications; 4) Development and feasibility study of bio-radar technology (system and data processing) for vital signs detection and

  17. SoilSCAPE in-Situ Observations of Soil Moisture for SMAP Validation: Pushing the Envelopes of Spatial Coverage and Energy Efficiency in Sparse Wireless Sensor Networks (Invited)

    NASA Astrophysics Data System (ADS)

    Moghaddam, M.; Silva, A.; Clewley, D.; Akbar, R.; Entekhabi, D.

    2013-12-01

    Soil Moisture Sensing Controller and oPtimal Estimator (SoilSCAPE) is a wireless in-situ sensor network technology, developed under the support of NASA ESTO/AIST program, for multi-scale validation of soil moisture retrievals from the Soil Moisture Active and Passive (SMAP) mission. The SMAP sensor suite is expected to produce soil moisture retrievals at 3 km scale from the radar instrument, at 36 km from the radiometer, and at 10 km from the combination of the two sensors. To validate the retrieved soil moisture maps at any of these scales, it is necessary to perform in-situ observations at multiple scales (ten, hundreds, and thousands of meters), representative of the true spatial variability of soil moisture fields. The most recent SoilSCAPE network, deployed in the California central valley, has been designed, built, and deployed to accomplish this goal, and is expected to become a core validation site for SMAP. The network consists of up to 150 sensor nodes, each comprised of 3-4 soil moisture sensors at various depths, deployed over a spatial extent of 36 km by 36 km. The network contains multiple sub-networks, each having up to 30 nodes, whose location is selected in part based on maximizing the land cover diversity within the 36 km cell. The network has achieved unprecedented energy efficiency, longevity, and spatial coverage using custom-designed hardware and software protocols. The network architecture utilizes a nested strategy, where a number of end devices (EDs) communicate to a local coordinator (LC) using our recently developed hardware with ultra-efficient circuitry and best-effort-timeslot allocation communication protocol. The LCs in turn communicates with the base station (BS) via text messages and a new compression scheme. The hardware and software technologies required to implement this latest deployment of the SoilSCAPE network will be presented in this paper, and several data sets resulting from the measurements will be shown. The data are

  18. Passive versus active local microrheology in mammalian cells and amoebae

    NASA Astrophysics Data System (ADS)

    Riviere, C.; Gazeau, F.; Marion, S.; Bacri, J.-C.; Wilhelm, C.

    2004-12-01

    We compare in this paper the rotational magnetic microrheology detailed by Marion et al [18] and Wilhelm et al [19] to the passive tracking microrheology. The rotational microrheology has been designed to explore, using magnetic rotating probes, the local intracellular microenvironment of living cells in terms of viscoelasticity. Passive microrheology techniques is based on the analysis of spontaneous diffusive motions of Brownian probes. The dependence of mean square displacement (MSD) with the time then directly reflects the type of movement (sub-, hyper- or diffusive motions). Using the same intracellular probes, we performed two types of measurements (active and passive). Based on the fluctuation-dissipation theorem, one should obtain the same information from the both techniques in a thermally equilibrium system. Interestingly, our measurements differ, and the discordances directly inform on active biological processes, which add to thermally activated fluctuations in our out-of equilibrium systems. In both cell models used, mammalian Hela cells and amoebae Entamoeba Histolytica, a hyper-diffusive regime at a short time is observed, which highlights the presence of an active non-thermal driving force, acting on the probe. However, the nature of this active force in mammalian cells and amoebae is different, according to their different phenotypes. In mammalian cells active processes are governed by the transport, via molecular motors, on the microtubule network. In amoebae, which are highly motile cells free of microtubule network, the active processes are dominated by strong fluxes of cytoplasm driven by extension of pseudopodia, in random directions, leading to an amplitude of motion one order of magnitude higher than for mammalian cells. Figs 7, Refs 32.

  19. Enhancing The USDA Global Crop Assessment Decision Support System Using Satellite-Based Soil Moisture Estimates Obtained From The Soil Moisture Active Passive Mission

    NASA Astrophysics Data System (ADS)

    Mladenova, I. E.; Bolten, J. D.; Crow, W. T.; Reynolds, C. A.

    2015-12-01

    The primary goal of the U.S. Department of Agriculture Foreign Agricultural Service (FAS) is to provide timely information on current and expected crop supply and demand estimates. Inter-annual variability in crop condition and crop productivity is largely controlled by the amount of available water to the plants. Thus, knowledge of the root-zone soil moisture is critical for the USDA's crop analysts. This information is currently provided by the modified Palmer model (PM). The PM is a two-layer, water balance-based hydrologic model that is driven by daily precipitation and daily minimum and maximum temperature observations based on ground meteorological station measurements from the World Meteorological Organization (WMO) and gridded weather data from the U.S. Air Force 557th Weather Wing (former U.S. Air Force Agency, AFWA). A data assimilation (DA) unit was added to the model to allow the integration of satellite-based soil moisture observations. The DA system was initially developed using retrievals from the Advanced Microwave Scanning Radiometer (AMSR-E), where the AMSR-E soil moisture estimates were ingested into the PM using a 1-D Ensemble Kalman Filter Approach. After the failure of AMSR-E the system was updated and it is currently set to ingest Soil Moisture Ocean Salinity (SMOS)-based retrievals. Operational delivery of the SMOS-based soil moisture product for USDA FAS began in spring, 2014. This talk will demonstrate the added value of assimilating satellite-based data and focus on work that is being done in preparation for updating the system by ingesting soil moisture observations from the Soil Moisture Active Passive (SMAP) mission. Soil moisture estimates derived using data obtained from SMOS and the Advanced Scatterometer (ASCAT) instrument on MetOp have been used as a proxy for the SMAP radiometer and radar products, respectively. The performance of this dual assimilation system would be assessed by examining the lagged rank cross correlation

  20. Soil Moisture Active Passive Mission: Fault Management Design Analyses

    NASA Technical Reports Server (NTRS)

    Meakin, Peter; Weitl, Raquel

    2013-01-01

    As a general trend, the complexities of modern spacecraft are increasing to include more ambitious mission goals with tighter timing requirements and on-board autonomy. As a byproduct, the protective features that monitor the performance of these systems have also increased in scope and complexity. Given cost and schedule pressures, there is an increasing emphasis on understanding the behavior of the system at design time. Formal test-driven verification and validation (V&V) is rarely able to test the significant combinatorics of states, and often finds problems late in the development cycle forcing design changes that can be costly. This paper describes the approach the SMAP Fault Protection team has taken to address some of the above-mentioned issues.

  1. Are passive red spirals truly passive?. The current star formation activity of optically red disc galaxies

    NASA Astrophysics Data System (ADS)

    Cortese, L.

    2012-07-01

    We used GALEX ultraviolet and WISE 22 μm observations to investigate the current star formation activity of the optically red spirals recently identified as part of the Galaxy Zoo project. These galaxies were accurately selected from the Sloan Digital Sky Survey as pure discs with low or no current star formation activity, representing one of the best optically selected samples of candidate passive spirals. However, we show that these galaxies are not only still forming stars at a significant rate (≳1 M⊙ yr-1) but, more importantly, their star formation activity is not different from that of normal star-forming discs of the same stellar mass (M∗ ≳ 1010.2 M⊙). Indeed, these systems lie on the UV-optical blue sequence, even without any corrections for internal dust attenuation, and they follow the same specific star formation rate vs. stellar mass relation of star-forming galaxies. Our findings clearly show that at high stellar masses, optical colours do not allow to distinguish between actively star-forming and truly quiescent systems.

  2. Comparison of SMOS and SMAP Soil Moisture Retrieval Approaches Using Tower-based Radiometer Data over a Vineyard Field

    NASA Technical Reports Server (NTRS)

    Miernecki, Maciej; Wigneron, Jean-Pierre; Lopez-Baeza, Ernesto; Kerr, Yann; DeJeu, Richard; DeLannoy, Gabielle J. M.; Jackson, Tom J.; O'Neill, Peggy E.; Shwank, Mike; Moran, Roberto Fernandez; Bircher, Simone; Laurence, Heather; Mialon, Arnaud; Bitar, Ahmad Al; Richaume, Philippe

    2014-01-01

    The objective of this study was to compare several approaches to soil moisture (SM) retrieval using L-band microwave radiometry. The comparison was based on a brightness temperature (TB) data set acquired since 2010 by the L-band radiometer ELBARA-II over a vineyard field at the Valencia Anchor Station (VAS) site. ELBARA-II, provided by the European Space Agency (ESA) within the scientific program of the SMOS (Soil Moisture and Ocean Salinity) mission, measures multiangular TB data at horizontal and vertical polarization for a range of incidence angles (30-60). Based on a three year data set (2010-2012), several SM retrieval approaches developed for spaceborne missions including AMSR-E (Advanced Microwave Scanning Radiometer for EOS), SMAP (Soil Moisture Active Passive) and SMOS were compared. The approaches include: the Single Channel Algorithm (SCA) for horizontal (SCA-H) and vertical (SCA-V) polarizations, the Dual Channel Algorithm (DCA), the Land Parameter Retrieval Model (LPRM) and two simplified approaches based on statistical regressions (referred to as 'Mattar' and 'Saleh'). Time series of vegetation indices required for three of the algorithms (SCA-H, SCA-V and Mattar) were obtained from MODIS observations. The SM retrievals were evaluated against reference SM values estimated from a multiangular 2-Parameter inversion approach. The results obtained with the current base line algorithms developed for SMAP (SCA-H and -V) are in very good agreement with the reference SM data set derived from the multi-angular observations (R2 around 0.90, RMSE varying between 0.035 and 0.056 m3m3 for several retrieval configurations). This result showed that, provided the relationship between vegetation optical depth and a remotely-sensed vegetation index can be calibrated, the SCA algorithms can provide results very close to those obtained from multi-angular observations in this study area. The approaches based on statistical regressions provided similar results and the

  3. Vegetation stress from soil moisture and chlorophyll fluorescence: synergy between SMAP and FLEX approaches

    NASA Astrophysics Data System (ADS)

    Moreno, Jose; Moran, Susan

    2014-05-01

    Vegetation stress detection continues being a focal objective for remote sensing techniques. It has implications not only for practical applications such as irrigation optimization or precision agriculture, but also for global climate models, providing data to better link water and carbon exchanges between the surface and the atmospheric and improved parameterization of the role of terrestrial vegetation in the coupling of water and carbon cycles. Traditional approaches to map vegetation stress using remote sensing techniques have been based on measurements of soil moisture status, canopy (radiometric) temperature and, to a lesser extent, canopy water content, but new techniques such as the dynamics of vegetation fluorescence emission, are also now available. Within the context of the preparatory activities for the SMAP and FLEX missions, a number of initiatives have been put in place to combine modelling activities and field experiments in order to look for alternative and more efficient ways of detecting vegetation stress, with emphasis on synergistic remote sensing approaches. The potential of solar-induced vegetation fluorescence as an early indicator of stress has been widely demonstrated, for different type of stress conditions: light amount (excess illumination) and conditions (direct/diffuse), temperature extremes (low and high), soil water availability (soil moisture), soil nutrients (nitrogen), atmospheric water vapour and atmospheric CO2 concentration. The effects caused by different stress conditions are sometimes difficult to be decoupled, also because different causes are often combined, but in general they then to change the overall fluorescence emission (modulating amplitude) or changing the relative contributions of photosystems PSI and PSII or the relative fluorescence re-absorption effects caused by modifications in the structure of pigment bed responsible for light absorption, in particular for acclimation for persistent stress conditions. While

  4. Experiences from long range passive and active imaging

    NASA Astrophysics Data System (ADS)

    Grönwall, Christina; Gustafsson, David; Steinvall, Ove; Tolt, Gustav

    2015-10-01

    We present algorithm evaluations for ATR of small sea vessels. The targets are at km distance from the sensors, which means that the algorithms have to deal with images affected by turbulence and mirage phenomena. We evaluate previously developed algorithms for registration of 3D-generating laser radar data. The evaluations indicate that some robustness to turbulence and mirage induced uncertainties can be handled by our probabilistic-based registration method. We also assess methods for target classification and target recognition on these new 3D data. An algorithm for detecting moving vessels in infrared image sequences is presented; it is based on optical flow estimation. Detection of moving target with an unknown spectral signature in a maritime environment is a challenging problem due to camera motion, background clutter, turbulence and the presence of mirage. First, the optical flow caused by the camera motion is eliminated by estimating the global flow in the image. Second, connected regions containing significant motions that differ from camera motion is extracted. It is assumed that motion caused by a moving vessel is more temporally stable than motion caused by mirage or turbulence. Furthermore, it is assumed that the motion caused by the vessel is more homogenous with respect to both magnitude and orientation, than motion caused by mirage and turbulence. Sufficiently large connected regions with a flow of acceptable magnitude and orientation are considered target regions. The method is evaluated on newly collected sequences of SWIR and MWIR images, with varying targets, target ranges and background clutter. Finally we discuss a concept for combining passive and active imaging in an ATR process. The main steps are passive imaging for target detection, active imaging for target/background segmentation and a fusion of passive and active imaging for target recognition.

  5. The Effect of Repetitive Passive and Active Movements on Proprioception Ability in Forearm Supination

    PubMed Central

    Kwon, OhSung; Lee, SeungWon; Lee, YoungWoo; Seo, DongKwon; Jung, SangWoo; Choi, WonJae

    2013-01-01

    [Purpose] This study was conducted in order to investigate the effect of repetitive passive movement and repetitive active movement on proprioception in forearm supination. [Subjects] This study had a cross-sectional design. Twenty-three right-handed healthy subjects were recruited. All subjects randomly received both repetitive passive movement and repetitive active movement (repetitive passive/active movement at 120°/s with 60 repetitions over a 0–80° range). Active and passive joint repositioning of all subjects was measured using the error score for position sense, both before and after repositioning intervention. [Results] In the repetitive passive movement test, there was a statistically significant decrease in the pre- versus post-repositioning error scores in the active and passive angle examinations. In the repetitive active movement test, there was a statistically significant increase in pre- versus post-repositioning error scores in the active and passive angle examinations. In the comparison of position sense, there was a statistically significant decrease in both active and passive angle repositioning error scores in repetitive passive movement versus repetitive active movement. [Conclusion] Repetitive passive movement improved the proprioception results for forearm supination, compared to repetitive active movement. Results of this study indicate that repetitive passive movement can be recommended to clinicians for rehabilitation therapy as it provides greater proprioception benefits. PMID:24259808

  6. Passive immunization and active vaccination against Hendra and Nipah viruses.

    PubMed

    Broder, C C

    2013-01-01

    Hendra virus and Nipah virus are viral zoonoses first recognized in the mid and late 1990's and are now categorized as the type species of the genus Henipavirus within the family Paramyxoviridae. Their broad species tropism together with their capacity to cause severe and often fatal disease in both humans and animals make Hendra and Nipah "overlap agents" and significant biosecurity threats. The development of effective vaccination strategies to prevent or treat henipavirus infection and disease has been an important area of research. Here, henipavirus active and passive vaccination strategies that have been examined in animal challenge models of Hendra and Nipah virus disease are summarized and discussed.

  7. Passive resting state and history of antagonist muscle activity shape active extensions in an insect limb

    PubMed Central

    Ache, Jan M.

    2012-01-01

    Limb movements can be driven by muscle contractions, external forces, or intrinsic passive forces. For lightweight limbs like those of insects or small vertebrates, passive forces can be large enough to overcome the effects of gravity and may even generate limb movements in the absence of active muscle contractions. Understanding the sources and actions of such forces is therefore important in understanding motor control. We describe passive properties of the femur-tibia joint of the locust hind leg. The resting angle is determined primarily by passive properties of the relatively large extensor tibiae muscle and is influenced by the history of activation of the fast extensor tibiae motor neuron. The resting angle is therefore better described as a history-dependent resting state. We selectively stimulated different flexor tibiae motor neurons to generate a range of isometric contractions of the flexor tibiae muscle and then stimulated the fast extensor tibiae motor neuron to elicit active tibial extensions. Residual forces in the flexor muscle have only a small effect on subsequent active extensions, but the effect is larger for distal than for proximal flexor motor neurons and varies with the strength of flexor activation. We conclude that passive properties of a lightweight limb make substantial and complex contributions to the resting state of the limb that must be taken into account in the patterning of neuronal control signals driving its active movements. Low variability in the effects of the passive forces may permit the nervous system to accurately predict their contributions to behavior. PMID:22357791

  8. Active versus passive maintenance of visual nonverbal memory.

    PubMed

    McKeown, Denis; Holt, Jessica; Delvenne, Jean-Francois; Smith, Amy; Griffiths, Benjamin

    2014-08-01

    Forgetting over the short term has challenged researchers for more than a century, largely because of the difficulty of controlling what goes on within the memory retention interval. But the "recent-negative-probe" procedure offers a valuable paradigm, by examining the influences of (presumably) unattended memoranda from prior trials. Here we used a recent-probe task to investigate forgetting for visual nonverbal short-term memory. The target stimuli (two visually presented abstract shapes) on a trial were followed after a retention interval by a probe, and participants indicated whether the probe matched one of the target items. Proactive interference, and hence memory for old trial probes, was observed, whereby participants were slowed in rejecting a nonmatching probe on the current trial that nevertheless matched a target item on the previous trial (a recent-negative probe). The attraction of the paradigm is that, by uncovering proactive influences of past-trial probe stimuli, it can be argued that active maintenance in memory of those probes is unlikely. In two experiments, we recorded such proactive interference of prior-trial items over a range of interstimulus (ISI) and intertrial (ITI) intervals (between 1 and 6 s, respectively). Consistent with a proposed two-process memory conception (the active-passive memory model, or APM), actively maintained memories on current trials decayed, but passively "maintained," or unattended, visual memories of stimuli on past trials did not. PMID:24390797

  9. Nondestructive assay using active and passive computed tomography

    SciTech Connect

    Roberson, G. P. ,LLNL

    1998-07-01

    The United States Department of Energy (DOE) has over 600,000 transuranic (TRU) waste drums temporarily stored at nearly 40 sites within the United States. Contents of these drums must be characterized before they are transported for permanent disposal. Traditional gamma-ray methods used to characterize nuclear waste introduce errors that are related to nonuniform measurement responses associated with unknown radioactive source and matrix material distributions. These errors can be reduced by application of tomographic techniques, that measure these distributions. The Lawrence Livermore National Laboratory (LLNL) has developed two tomographic-based waste assay systems. They use external radioactive sources and tomography-protocol to map the attenuation within a waste drum as a function of mono-energetic gamma-ray energy in waste containers. Passive tomography is used to localize and identify specific radioactive waste contents within the same waste containers. Reconstruction of the passive data via the active images allows internal waste radioactivities in a drum to be corrected for any overlying heterogeneous materials, thus yielding an absolute assay of the waste radioactivities. Calibration of both systems requires only point source measurements and are independent of matrix materials. The first system is housed at LLNL and was developed to study and validate research concepts. The second system is being developed with Bioimaging Research, Inc. (BIR) and is housed within a mobile waste characterization trailer. This system has traveled to three DOE facilities to demonstrate the active and passive computed tomography capability. Both systems have participated in and successfully passed the requirements of formal DOE-sponsored intercomparison studies. The systems have measured approximately 1 to 100 grains of plutonium within a variety of waste matrix materials. Laboratory and field results from these two systems over the past several years show that both systems

  10. Passive and active EO sensing of small surface vessels

    NASA Astrophysics Data System (ADS)

    Steinvall, Ove; Berglund, Folke; Allard, Lars; Öhgren, Johan; Larsson, Hâkan; Amselem, Elias; Gustafsson, Frank; Repasi, Endre; Lutzmann, Peter; Göhler, Benjamin; Hammer, Marcus; McEwen, Kennedy; McEwan, Ken

    2015-10-01

    The detection and classification of small surface targets at long ranges is a growing need for naval security. This paper will present an overview of a measurement campaign which took place in the Baltic Sea in November 2014. The purpose was to test active and passive EO sensors (10 different types) for the detection, tracking and identification of small sea targets. The passive sensors were covering the visual, SWIR, MWIR and LWIR regions. Active sensors operating at 1.5 μm collected data in 1D, 2D and 3D modes. Supplementary sensors included a weather station, a scintillometer, as well as sensors for positioning and attitude determination of the boats. Three boats in the class 4-9 meters were used as targets. After registration of the boats at close range they were sent out to 5-7 km distance from the sensor site. At the different ranges the target boats were directed to have different aspect angles relative to the direction of observation. Staff from IOSB Fraunhofer in Germany and from Selex (through DSTL) in UK took part in the tests beside FOI who was arranging the trials. A summary of the trial and examples of data and imagery will be presented.

  11. Assimilation of passive and active microwave soil moisture retrievals

    NASA Astrophysics Data System (ADS)

    Draper, C. S.; Reichle, R. H.; De Lannoy, G. J. M.; Liu, Q.

    2012-02-01

    Near-surface soil moisture observations from the active microwave ASCAT and the passive microwave AMSR-E satellite instruments are assimilated, both separately and together, into the NASA Catchment land surface model over 3.5 years using an ensemble Kalman filter. The impact of each assimilation is evaluated using in situ soil moisture observations from 85 sites in the US and Australia, in terms of the anomaly time series correlation-coefficient, R. The skill gained by assimilating either ASCAT or AMSR-E was very similar, even when separated by land cover type. Over all sites, the mean root-zone R was significantly increased from 0.45 for an open-loop, to 0.55, 0.54, and 0.56 by the assimilation of ASCAT, AMSR-E, and both, respectively. Each assimilation also had a positive impact over each land cover type sampled. For maximum accuracy and coverage it is recommended that active and passive microwave observations be assimilated together.

  12. Active-to-Passive Environmental Cleanup Transition Strategies - 13220

    SciTech Connect

    Gaughan, Thomas F.; Aylward, Robert S.; Denham, Miles E.; Looney, Brian B.; Whitaker, Wade C.; Mills, Gary L.

    2013-07-01

    The Savannah River Site uses a graded approach to environmental cleanup. The selection of groundwater and vadose zone remediation technologies for a specific contamination area is based on the size, contaminant type, contaminant concentration, and configuration of the plume. These attributes are the result of the nature and mass of the source of contamination and the subsurface characteristics in the area of the plume. Many large plumes consist of several zones that are most efficiently addressed with separate complementary corrective action/remedial technologies. The highest concentrations of contaminants are found in the source zone. The most robust, high mass removal technologies are often best suited for remediation of the source zone. In the primary plume zone, active remedies, such as pump-and-treat, may be necessary to remove contaminants and exert hydraulic control of the plume. In the dilute fringe zone, contaminants are generally lower in concentration and can often be treated with passive techniques. A key determination in achieving an acceptable and cost-effective end state for a given waste unit is when to transition from an active treatment system to a more passive or natural approach (e.g., monitored natural attenuation or enhanced attenuation). This paper will discuss the considerations for such a transition as well as provide examples of successful transitions at the Savannah River Site. (authors)

  13. Propulsion by passive filaments and active flagella near boundaries.

    PubMed

    Evans, Arthur A; Lauga, Eric

    2010-10-01

    Confinement and wall effects are known to affect the kinematics and propulsive characteristics of swimming microorganisms. When a solid body is dragged through a viscous fluid at constant velocity, the presence of a wall increases fluid drag, and thus the net force required to maintain speed has to increase. In contrast, recent optical trapping experiments have revealed that the propulsive force generated by human spermatozoa is decreased by the presence of boundaries. Here, we use a series of simple models to analytically elucidate the propulsive effects of a solid boundary on passively actuated filaments and model flagella. For passive flexible filaments actuated periodically at one end, the presence of the wall is shown to increase the propulsive forces generated by the filaments in the case of displacement-driven actuation, while it decreases the force in the case of force-driven actuation. In the case of active filaments as models for eukaryotic flagella, we demonstrate that the manner in which a solid wall affects propulsion cannot be known a priori, but is instead a nontrivial function of the flagellum frequency, wavelength, its material characteristics, the manner in which the molecular motors self-organize to produce oscillations (prescribed activity model or self-organized axonemal beating model), and the boundary conditions applied experimentally to the tethered flagellum. In particular, we show that in some cases, the increase in fluid friction induced by the wall can lead to a change in the waveform expressed by the flagella, which results in a decrease in their propulsive force.

  14. Propulsion by passive filaments and active flagella near boundaries

    NASA Astrophysics Data System (ADS)

    Evans, Arthur A.; Lauga, Eric

    2010-10-01

    Confinement and wall effects are known to affect the kinematics and propulsive characteristics of swimming microorganisms. When a solid body is dragged through a viscous fluid at constant velocity, the presence of a wall increases fluid drag, and thus the net force required to maintain speed has to increase. In contrast, recent optical trapping experiments have revealed that the propulsive force generated by human spermatozoa is decreased by the presence of boundaries. Here, we use a series of simple models to analytically elucidate the propulsive effects of a solid boundary on passively actuated filaments and model flagella. For passive flexible filaments actuated periodically at one end, the presence of the wall is shown to increase the propulsive forces generated by the filaments in the case of displacement-driven actuation, while it decreases the force in the case of force-driven actuation. In the case of active filaments as models for eukaryotic flagella, we demonstrate that the manner in which a solid wall affects propulsion cannot be known a priori, but is instead a nontrivial function of the flagellum frequency, wavelength, its material characteristics, the manner in which the molecular motors self-organize to produce oscillations (prescribed activity model or self-organized axonemal beating model), and the boundary conditions applied experimentally to the tethered flagellum. In particular, we show that in some cases, the increase in fluid friction induced by the wall can lead to a change in the waveform expressed by the flagella, which results in a decrease in their propulsive force.

  15. Passive and active control of boundary layer transition

    NASA Astrophysics Data System (ADS)

    Nosenchuck, Daniel Mark

    It is well known that laminar-turbulent boundary layer transition is initiated by the formation of Tollmien-Schlichting laminar instability waves. The amplification rates of these waves are strongly dependent on the shape of the boundary layer velocity profile. Consequently, the transition process can be controlled by modifying the velocity profile. This can be accomplished by controlling the pressure gradient (dp/dx), using boundary layer suction, installing surface roughness elements, or by surface heating or cooling. Methods used to modify the transition process through changes in the mean velocity profile are called "passive" in this paper. There exists a large set of experiments and theory on the application of passive methods for boundary layer control. In the present work only surface heating will be addressed.Transition measurements were made on a heated flat plate in water. Results are presented for several plate wall temperature distributions. An increase by a factor of 2.5 in transition Reynolds number was observed for a 5°C isothermal wall overheat. Buoyancy effects on transition were minimal due to the small Richardson and Grashof numbers encountered in the experiments.The amplification of laminar instability waves is comparatively to process, taking place over many boundary layer thicknesses. After the slow amplification of the laminar instability waves, transition occurs by a strong three dimensional dynamic instability. It appears possible to attenuate (or reinforce) the instability waves by introducing amplitude-and phase-controlled perturbations into the laminar boundary layer using feedback control system. This method is called "active" control and forms the larger part of the research reported in this thesis.A combination of sensors, activators and feedback control electronics is required for active control. The sensors used in the experiments are flush-mounted hot film wall shear robes. A new type of activator was developed using thin, flush

  16. Fluctuation driven active molecular transport in passive channel proteins

    NASA Astrophysics Data System (ADS)

    Kosztin, Ioan

    2006-03-01

    Living cells interact with their extracellular environment through the cell membrane, which acts as a protective permeability barrier for preserving the internal integrity of the cell. However, cell metabolism requires controlled molecular transport across the cell membrane, a function that is fulfilled by a wide variety of transmembrane proteins, acting as either passive or active transporters. In this talk it is argued that, contrary to the general belief, in active cell membranes passive and spatially asymmetric channel proteins can act as active transporters by consuming energy from nonequilibrium fluctuations fueled by cell metabolism. This assertion is demonstrated in the case of the E. coli aquaglyceroporin GlpF channel protein, whose high resolution crystal structure is manifestly asymmetric. By calculating the glycerol flux through GlpF within the framework of a stochastic model, it is found that, as a result of channel asymmetry, glycerol uptake driven by a concentration gradient is enhanced significantly in the presence of non-equilibrium fluctuations. Furthermore, the enhancement caused by a ratchet-like mechanism is larger for the outward, i.e., from the cytoplasm to the periplasm, flux than for the inward one, suggesting that the same non-equilibrium fluctuations also play an important role in protecting the interior of the cell against poisoning by excess uptake of glycerol. Preliminary data on water and sugar transport through aquaporin and maltoporin channels, respectively, are indicative of the universality of the proposed nonequilibrium-fluctuation-driven active transport mechanism. This work was supported by grants from the Univ. of Missouri Research Board, the Institute for Theoretical Sciences and the Department of Energy (DOE Contract W-7405-ENG-36), and the National Science Foundation (FIBR-0526854).

  17. Biological aerosol detection with combined passive-active infrared measurements

    NASA Astrophysics Data System (ADS)

    Ifarraguerri, Agustin I.; Vanderbeek, Richard G.; Ben-David, Avishai

    2004-12-01

    A data collection experiment was performed in November of 2003 to measure aerosol signatures using multiple sensors, all operating in the long-wave infrared. The purpose of this data collection experiment was to determine whether combining passive hyperspectral and LIDAR measurements can substantially improve biological aerosol detection performance. Controlled releases of dry aerosols, including road dust, egg albumin and two strains of Bacillus Subtilis var. Niger (BG) spores were performed using the ECBC/ARTEMIS open-path aerosol test chamber located in the Edgewood Area of Aberdeen Proving Grounds, MD. The chamber provides a ~ 20' path without optical windows. Ground truth devices included 3 aerodynamic particle sizers, an optical particle size spectrometer, 6 nephelometers and a high-volume particle sampler. Two sensors were used to make measurements during the test: the AIRIS long-wave infrared imaging spectrometer and the FAL CO2 LIDAR. The AIRIS and FAL data sets were analyzed for detection performance relative to the ground truth. In this paper we present experimental results from the individual sensors as well as results from passive-active sensor fusion. The sensor performance is presented in the form of receiver operating characteristic curves.

  18. Passive and active recognition of one's own face.

    PubMed

    Sugiura, M; Kawashima, R; Nakamura, K; Okada, K; Kato, T; Nakamura, A; Hatano, K; Itoh, K; Kojima, S; Fukuda, H

    2000-01-01

    Facial identity recognition has been studied mainly with explicit discrimination requirement and faces of social figures in previous human brain imaging studies. We performed a PET activation study with normal volunteers in facial identity recognition tasks using the subject's own face as visual stimulus. Three tasks were designed so that the activation of the visual representation of the face and the effect of sustained attention to the representation could be separately examined: a control-face recognition task (C), a passive own-face recognition task (no explicit discrimination was required) (P), and an active own-face recognition task (explicit discrimination was required) (A). Increased skin conductance responses during recognition of own face were seen in both task P and task A, suggesting the occurrence of psychophysiological changes during recognition of one's own face. The left fusiform gyrus, the right supramarginal gyrus, the left putamen, and the right hypothalamus were activated in tasks P and A compared with task C. The left fusiform gyrus and the right supramarginal gyrus are considered to be involved in the representation of one's own face. The activation in the right supramarginal gyrus may be associated with the representation of one's own face as a part of one's own body. The prefrontal cortices, the right anterior cingulate, the right presupplementary motor area, and the left insula were specifically activated during task A compared with tasks C and P, indicating that these regions may be involved in the sustained attention to the representation of one's own face. PMID:10686115

  19. Maternal Active and Passive Smoking and Hypertensive Disorders of Pregnancy

    PubMed Central

    Engel, Stephanie M.; Scher, Erica; Wallenstein, Sylvan; Savitz, David A.; Alsaker, Elin R.; Trogstad, Lill; Magnus, Per

    2014-01-01

    Background The inverse association between prenatal smoking and preeclampsia is puzzling, given the increased risks of prematurity and low birthweight associated with both smoking and preeclampsia. We analyzed the Norwegian Mother and Child Birth Cohort (MoBa) to determine whether the associations varied by timing of prenatal smoking. Methods We conducted an analysis of 74,439 singleton pregnancies with completed second- and third- trimester questionnaires. Active and passive smoke exposure by trimester were determined by maternal self-report, and covered the period of preconception through approximately 30 weeks’ gestation. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Results Rates of active smoking declined dramatically during pregnancy: for trimester 1, 23%; trimester 2, 9%; and trimester 3, 8%. Active smoking in the third trimester was associated with reduced odds of preeclampsia and gestational hypertension, with the strongest association among continuous smokers (for preeclampsia, OR = 0.57 [95% CI = 0.46–0.70]). Women who quit smoking before the third trimester had approximately the same risk of preeclampsia and gestational hypertension as nonsmokers. There was some evidence of dose-response, with the heaviest smokers (more than eight cigarettes per day) having the lowest risks of preeclampsia (0.48 [0.32–0.73]) and gestational hypertension (0.51 [0.28–0.95]). There was little evidence of an association with passive smoking exposure. Conclusion The association between smoking and preeclampsia varies substantially according to the timing and intensity of exposure. A better understanding of the biologic pathways that underlie these associations may provide important clues to the etiology of preeclampsia and the development of effective clinical interventions. PMID:23429405

  20. Technology advances in active and passive microwave sensing through 1985

    NASA Technical Reports Server (NTRS)

    Barath, F. T.

    1977-01-01

    As a result of a growing awareness by the remote sensing community of the unique capabilities of passive and active microwave sensors, these instruments are expected to grow in the next decade in numbers, versatility and complexity. The Nimbus-G and Seasat-A Scanning Multichannel Microwave Spectrometer (SMMR), the Seasat-A radar altimeter, scatterometer and synthetic aperture radar represent the first systematic attempt at exploring a wide variety of applications utilizing microwave sensing techniques and are indicators of the directions in which the pertinent technology is likely to evolve. The trend is toward high resolution multi-frequency imagers spanning wide frequency ranges and wide swaths requiring sophisticated receivers, real-time data processors and most importantly, complex antennas.

  1. Passive and active EO sensing close to the sea surface

    NASA Astrophysics Data System (ADS)

    Steinvall, Ove; Persson, Rolf; Berglund, Folke; Öhgren, Johan; Gustafsson, Frank

    2014-10-01

    The present paper investigates the use of an eye-safe laser rangefinder at 1.5 μm and TV/IR imaging to obtain information on atmospheric properties at various paths close to the sea surface. On one day active/passive imaging NIR and SWIR systems were also used. The paper will describe the experimental equipment and the results from measurements of atmospheric backscatter as well as TV and IR images of test targets along a 1.8 km path close to the Baltic Sea. The site also contained a weather station and a scintillometer for logging weather and turbulence parameters. Results correlating the lidar attenuation with the imaging performance will be given and compared with models.

  2. Advances in Inner Magnetosphere Passive and Active Wave Research

    NASA Technical Reports Server (NTRS)

    Green, James L.; Fung, Shing F.

    2004-01-01

    This review identifies a number of the principal research advancements that have occurred over the last five years in the study of electromagnetic (EM) waves in the Earth's inner magnetosphere. The observations used in this study are from the plasma wave instruments and radio sounders on Cluster, IMAGE, Geotail, Wind, Polar, Interball, and others. The data from passive plasma wave instruments have led to a number of advances such as: determining the origin and importance of whistler mode waves in the plasmasphere, discovery of the source of kilometric continuum radiation, mapping AKR source regions with "pinpoint" accuracy, and correlating the AKR source location with dipole tilt angle. Active magnetospheric wave experiments have shown that long range ducted and direct echoes can be used to obtain the density distribution of electrons in the polar cap and along plasmaspheric field lines, providing key information on plasmaspheric filling rates and polar cap outflows.

  3. Active/passive mode-locked laser oscillator

    DOEpatents

    Fountain, William D.; Johnson, Bertram C.

    1977-01-01

    A Q-switched/mode-locked Nd:YAG laser oscillator employing simultaneous active (electro-optic) and passive (saturable absorber) loss modulation within the optical cavity is described. This "dual modulation" oscillator can produce transform-limited pulses of duration ranging from about 30 psec to about 5 nsec with greatly improved stability compared to other mode-locked systems. The pulses produced by this system lack intrapulse frequency or amplitude modulation, and hence are idealy suited for amplification to high energies and for other applications where well-defined pulses are required. Also, the pulses of this system have excellent interpulse characteristics, wherein the optical noise between the individual pulses of the pulse train has a power level well below the power of the peak pulse of the train.

  4. Waves in active and passive periodic structures - A review

    NASA Technical Reports Server (NTRS)

    Elachi, C.

    1976-01-01

    The theory and recent applications of waves in periodic structures are reviewed. Both the Floquet and coupled waves approach are analyzed in some detail. The theoretical part of the paper includes wave propagation in unbounded and bounded active or passive periodic media, wave scattering from periodic boundaries, source radiation (dipole, Cerenkov, transition, and Smith-Purcell) in periodic media, and pulse transmission through a periodic slab. The applications part covers the recent development in a variety of fields: distributed feedback oscillators, filters, mode converters, couplers, second-harmonic generators, deflectors, modulators, and transducers in the fields of integrated optics and integrated surface acoustics. Work on insect compound eyes, mechanical structures, ocean waves, pulse compressions, temperature waves, and cholesteric liquid crystals, and particles interaction with crystals is briefly reviewed, especially in the case of zeolite crystals and superlattices. Recent advances in fabrication techniques for very fine gratings are also covered.

  5. Advances in Assimilation of Satellite-Based Passive Microwave Observations for Soil-Moisture Estimation

    NASA Technical Reports Server (NTRS)

    De Lannoy, Gabrielle J. M.; Pauwels, Valentijn; Reichle, Rolf H.; Draper, Clara; Koster, Randy; Liu, Qing

    2012-01-01

    Satellite-based microwave measurements have long shown potential to provide global information about soil moisture. The European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS, [1]) mission as well as the future National Aeronautics and Space Administration (NASA) Soil Moisture Active and Passive (SMAP, [2]) mission measure passive microwave emission at L-band frequencies, at a relatively coarse (40 km) spatial resolution. In addition, SMAP will measure active microwave signals at a higher spatial resolution (3 km). These new L-band missions have a greater sensing depth (of -5cm) compared with past and present C- and X-band microwave sensors. ESA currently also disseminates retrievals of SMOS surface soil moisture that are derived from SMOS brightness temperature observations and ancillary data. In this research, we address two major challenges with the assimilation of recent/future satellite-based microwave measurements: (i) assimilation of soil moisture retrievals versus brightness temperatures for surface and root-zone soil moisture estimation and (ii) scale-mismatches between satellite observations, models and in situ validation data.

  6. Active versus Passive Teaching Styles: An Empirical Study of Student Learning Outcomes

    ERIC Educational Resources Information Center

    Michel, Norbert; Cater, John James, III; Varela, Otmar

    2009-01-01

    This study compares the impact of an active teaching approach and a traditional (or passive) teaching style on student cognitive outcomes. Across two sections of an introductory business course, one class was taught in an active or nontraditional manner, with a variety of active learning exercises. The second class was taught in a passive or…

  7. Sympathetic activity during passive heat stress in healthy aged humans

    PubMed Central

    Gagnon, Daniel; Schlader, Zachary J; Crandall, Craig G

    2015-01-01

    Abstract Cardiovascular adjustments during heat stress are generally attenuated in healthy aged humans, which could be due to lower increases in sympathetic activity compared to the young. We compared muscle sympathetic nerve activity (MSNA) between 11 young (Y: 28 ± 4 years) and 10 aged (A: 70 ± 5 years) subjects prior to and during passive heating. Furthermore, MSNA responses were compared when a cold pressor test (CPT) and lower body negative pressure (LBNP) were superimposed upon heating. Baseline MSNA burst frequency (Y: 15 ± 4 vs. A: 31 ± 3 bursts min−1, P ≤ 0.01) and burst incidence (Y: 26 ± 8 vs. A: 50 ± 7 bursts (100 cardiac cycles (CC))−1, P ≤ 0.01) were greater in the aged. Heat stress increased core temperature to a similar extent in both groups (Y: +1.2 ± 0.1 vs. A: +1.2 ± 0.0°C, P = 0.99). Absolute levels of MSNA remained greater in the aged during heat stress (burst frequency: Y: 47 ± 6 vs. A: 63 ± 11 bursts min−1, P ≤ 0.01; burst incidence: Y: 48 ± 8 vs. A: 67 ± 9 bursts (100 CC)−1, P ≤ 0.01); however, the increase in both variables was similar between groups (both P ≥ 0.1). The CPT and LBNP further increased MSNA burst frequency and burst incidence, although the magnitude of increase was similar between groups (both P ≥ 0.07). These results suggest that increases in sympathetic activity during heat stress are not attenuated in healthy aged humans. Key points Cardiovascular adjustments to heat stress are attenuated in healthy aged individuals, which could contribute to their greater prevalence of heat-related illnesses and deaths during heat waves. The attenuated cardiovascular adjustments in the aged could be due to lower increases in sympathetic nerve activity during heat stress. We examined muscle sympathetic nerve activity (MSNA) and plasma catecholamine concentrations in healthy young and aged individuals during whole-body passive heat stress. The main finding

  8. Resolving the active versus passive conundrum for head direction cells.

    PubMed

    Shinder, M E; Taube, J S

    2014-06-13

    Head direction (HD) cells have been identified in a number of limbic system structures. These cells encode the animal's perceived directional heading in the horizontal plane and are dependent on an intact vestibular system. Previous studies have reported that the responses of vestibular neurons within the vestibular nuclei are markedly attenuated when an animal makes a volitional head turn compared to passive rotation. This finding presents a conundrum in that if vestibular responses are suppressed during an active head turn how is a vestibular signal propagated forward to drive and update the HD signal? This review identifies and discusses four possible mechanisms that could resolve this problem. These mechanisms are: (1) the ascending vestibular signal is generated by more than just vestibular-only neurons, (2) not all vestibular-only neurons contributing to the HD pathway have firing rates that are attenuated by active head turns, (3) the ascending pathway may be spared from the affects of the attenuation in that the HD system receives information from other vestibular brainstem sites that do not include vestibular-only cells, and (4) the ascending signal is affected by the inhibited vestibular signal during an active head turn, but the HD circuit compensates and uses the altered signal to accurately update the current HD. Future studies will be needed to decipher which of these possibilities is correct.

  9. Information System Life-Cycle And Documentation Standards (SMAP DIDS)

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Although not computer program, SMAP DIDS written to provide systematic, NASA-wide structure for documenting information system development projects. Each DID (data item description) outlines document required for top-quality software development. When combined with management, assurance, and life cycle standards, Standards protect all parties who participate in design and operation of new information system.

  10. Passive, integrated measurement of indoor radon using activated carbon.

    PubMed

    George, A C

    1984-04-01

    Activated carbon canisters were tested to determine their adsorption and retention characteristics for radon. Our tests conducted indoors under typical conditions of temperature and relative humidity indicate that simple, inexpensive and maintenance-free passive devices containing 150-200 g of activated carbon can measure radon conveniently and adequately. The amount of radon absorbed in the collector is determined by counting the gamma rays from the decay products of radon. The lower limit of detection for radon is 0.2 pCi/l. for an exposure of 72 hr. Greater sensitivity can be obtained with larger counting systems and devices containing carbon with more surface area. Tests in a residential building and in a test chamber indicate that the measured radon in the canister is proportional to the mean concentration of radon during the period of exposure when correction for relative humidity is made. For practical situations encountered indoors, the device yields results accurate to within +/- 20%. Results from field measurements indicate that the use of the device is feasible.

  11. Passive and Active Stabilization of Liquid Bridges in Low Gravity

    NASA Technical Reports Server (NTRS)

    Marston, Philip L.; Thiessen, David B.; Marr-Lyon, Mark J.; Wei, Wei; Niederhaus, Charles E.; Truong, Duc K.

    2001-01-01

    Tests are planned in the low gravity environment of the International Space Station (ISS) of new methods for the suppression of the capillary instability of liquid bridges. Our suppression methods are unusual in that they are not limited to liquid bridges having very special properties and may impact a variety of low-gravity and earth-based technologies. There are two main approaches to be investigated: (1) Passive Acoustic Stabilization (PAS); and (2) Active Electrostatic Stabilization (AES). In PAS, the suppression of the mode growth is accomplished by placing the bridge in an acoustic field having the appropriate properties such that the acoustic radiation pressure automatically pulls outward on the thinnest portion of the bridge. In AES, the bridge deformation is sensed optically and counteracted by actively adjusting the electrostatic Maxwell stresses via two ring electrodes concentric with the slightly conducting bridge to offset the growth of the unstable mode. While the present work emphasizes cylindrical bridges, the methods need not be restricted to that case. The methods to be explored are relevant to the suppression of capillary instabilities in floating zone crystal growth, breakup of liquid jets and columns, bubbles, and annular films as well as the management of coolants or propellants in low-gravity.

  12. [Specific features of fear conditioning expression in active and passive rabbits].

    PubMed

    2013-11-01

    The active and passive rabbits selected previously on the basis of their behavior in open field and light-dark test, were subjected to fear conditioning using pairing light (4 s) with footshocks (10 Hz, 0.5 s). Heart rate and respiration rate were measured during the classical fear conditioning. Heart rate and respiration rate decreased in response to light before footshock in case of passive-defensive reaction. There were no heart rate and respiration rate reduction in the course of the active defensive reaction. In active rabbits, as compared to passive ones, the frequency of active locomotors reactions and heart rate were higher, the decrease of respiration rate to light was observed at later stages of training, and the detected bradycardia was not stable. Thus, based upon vegetative characteristics, the active rabbits had lower level of fear than passive ones. The active or passive behavioral strategies of animals were preserved during fear conditioning.

  13. MCT SWIR modules for passive and active imaging applications

    NASA Astrophysics Data System (ADS)

    Breiter, R.; Benecke, M.; Eich, D.; Figgemeier, H.; Weber, A.; Wendler, J.; Sieck, A.

    2016-05-01

    Based on AIM's state-of-the-art MCT IR technology, detector modules for the SWIR spectral range have been developed, fabricated and characterized. While LPE grown MCT FPAs with extended 2.5μm cut-off have been fabricated and integrated also MBE grown MCT on GaAs is considered for future production. Two imaging applications have been in focus operating either in passive mode by making use of e.g. the night glow, or in active mode by laser illumination for gated viewing. Dedicated readout integrated circuits (ROIC), realized in 0.18μm Si-CMOS technology providing the required functionality for passive imaging and gated imaging, have been designed and implemented. For both designs a 640x512 15μm pitch format was chosen. The FPAs are integrated in compact dewar cooler configurations using AIM's split linear coolers. A command and control electronics (CCE) provides supply voltages, biasing, clocks, control and video digitization for easy system interfacing. For imaging under low-light conditions a low-noise 640x512 15μm pitch ROIC with CTIA input stages and correlated double sampling was designed. The ROIC provides rolling shutter and snapshot integration. To reduce size, weight, power and cost (SWaP-C) a 640x512 format detector in a 10μm pitch is under development. The module makes use of the extended SWIR spectral cut-off up to 2.5μm. To be used for active gated-viewing operation SWIR MCT avalanche photodiodes have been implemented and characterized on FPA level in a 640x512 15μm pitch format. The specific ROIC provides also the necessary functions for range gate control and triggering by the laser illumination. First lab and field tests of a gated viewing demonstrator have been carried out. The paper will present the development status and performance results of AIM's MCT based SWIR Modules for imaging applications.

  14. The Relationship Between Passive and Active Vocabularies: Effects of Language Learning Context.

    ERIC Educational Resources Information Center

    Laufer, Batia; Paribakht, T. Sima

    1998-01-01

    Investigated the relationships among three types of vocabulary knowledge (passive, controlled active, and free active) within the same individuals, taking four variables into consideration: passive vocabulary size, language learning context, second (L2) for foreign (FL), length of residence in L2 context, and, among the Canadians, knowledge of…

  15. Biomarkers of Induced Active and Passive Smoking Damage

    PubMed Central

    Lodovici, Maura; Bigagli, Elisabetta

    2009-01-01

    In addition to the well-known link between smoking and lung cancer, large epidemiological studies have shown a relationship between smoking and cancers of the nose, oral cavity, oropharynx, larynx, esophagus, pancreas, bladder, kidney, stomach, liver, colon and cervix, as well as myeloid leukemia. Epidemiological evidence has reported a direct link between exposure of non-smokers to environmental tobacco smoke and disease, most notably, lung cancer. Much evidence demonstrates that carcinogenic-DNA adducts are useful markers of tobacco smoke exposure, providing an integrated measurement of carcinogen intake, metabolic activation, and delivery to the DNA in target tissues. Monitoring accessible surrogate tissues, such as white blood cells or bronchoalveolar lavage (BAL) cells, also provides a means of investigating passive and active tobacco exposure in healthy individuals and cancer patients. Levels of DNA adducts measured in many tissues of smokers are significantly higher than in non-smokers. While some studies have demonstrated an association between carcinogenic DNA adducts and cancer in current smokers, no association has been observed in ex or never smokers. The role of genetic susceptibility in the development of smoking related-cancer is essential. In order to establish whether smoking-related DNA adducts are biomarkers of tobacco smoke exposure and/or its carcinogenic activity we summarized all data that associated tobacco smoke exposure and smoking-related DNA adducts both in controls and/or in cancer cases and studies where the effect of genetic polymorphisms involved in the activation and deactivation of carcinogens were also evaluated. In the future we hope we will be able to screen for lung cancer susceptibility by using specific biomarkers and that subjects of compared groups can be stratified for multiple potential modulators of biomarkers, taking into account various confounding factors. PMID:19440419

  16. Impact of hydrodynamics on effective interactions in suspensions of active and passive matter.

    PubMed

    Krafnick, Ryan C; García, Angel E

    2015-02-01

    Passive particles exhibit unique properties when immersed in an active bath of self-propelling entities. In particular, an effective attraction can appear between particles that repel each other when in a passive solution. Here we numerically study the effect of hydrodynamics on an active-passive hybrid system, where we observe qualitative differences as compared to simulations with excluded volume effects alone. The results shed light on an existing discrepancy in pair lifetimes between simulation and experiment, due to the hydrodynamically enhanced stability of coupled passive particles. PMID:25768506

  17. Impact of hydrodynamics on effective interactions in suspensions of active and passive matter

    NASA Astrophysics Data System (ADS)

    Krafnick, Ryan C.; García, Angel E.

    2015-02-01

    Passive particles exhibit unique properties when immersed in an active bath of self-propelling entities. In particular, an effective attraction can appear between particles that repel each other when in a passive solution. Here we numerically study the effect of hydrodynamics on an active-passive hybrid system, where we observe qualitative differences as compared to simulations with excluded volume effects alone. The results shed light on an existing discrepancy in pair lifetimes between simulation and experiment, due to the hydrodynamically enhanced stability of coupled passive particles.

  18. Passive Joint Forces Are Tuned to Limb Use in Insects and Drive Movements without Motor Activity

    PubMed Central

    Ache, Jan M.; Matheson, Thomas

    2013-01-01

    Summary Background Limb movements are generally driven by active muscular contractions working with and against passive forces arising in muscles and other structures. In relatively heavy limbs, the effects of gravity and inertia predominate, whereas in lighter limbs, passive forces intrinsic to the limb are of greater consequence. The roles of passive forces generated by muscles and tendons are well understood, but there has been little recognition that forces originating within joints themselves may also be important, and less still that these joint forces may be adapted through evolution to complement active muscle forces acting at the same joint. Results We examined the roles of passive joint forces in insect legs with different arrangements of antagonist muscles. We first show that passive forces modify actively generated movements of a joint across its working range, and that they can be sufficiently strong to generate completely passive movements that are faster than active movements observed in natural behaviors. We further demonstrate that some of these forces originate within the joint itself. In legs of different species adapted to different uses (walking, jumping), these passive joint forces complement the balance of strength of the antagonist muscles acting on the joint. We show that passive joint forces are stronger where they assist the weaker of two antagonist muscles. Conclusions In limbs where the dictates of a key behavior produce asymmetry in muscle forces, passive joint forces can be coadapted to provide the balance needed for the effective generation of other behaviors. PMID:23871240

  19. Realistic Instrumentation Platform for Active and Passive Optical Remote Sensing.

    PubMed

    Brydegaard, Mikkel; Merdasa, Aboma; Gebru, Alem; Jayaweera, Hiran; Svanberg, Sune

    2016-02-01

    We describe the development of a novel versatile optical platform for active and passive remote sensing of environmental parameters. Applications include assessment of vegetation status and water quality. The system is also adapted for ecological studies, such as identification of flying insects including agricultural pests. The system is based on two mid-size amateur astronomy telescopes, continuous-wave diode lasers at different wavelengths ranging from violet to the near infrared, and detector facilities including quadrant photodiodes, two-dimensional and line scan charge-coupled device cameras, and a compact digital spectrometer. Application examples include remote Ramanlaser-induced fluorescence monitoring of water quality at 120 m distance, and insect identification at kilometer ranges using the recorded wing beat frequency and its spectrum of overtones. Because of the low cost this developmental platform is very suitable for advanced research projects in developing countries and has, in fact, been multiplied during hands-on workshops and is now being used by a number of groups at African universities.

  20. Confronting Passive and Active Sensors with Non-Gaussian Statistics

    PubMed Central

    Rodríguez-Gonzálvez, Pablo.; Garcia-Gago, Jesús.; Gomez-Lahoz, Javier.; González-Aguilera, Diego.

    2014-01-01

    This paper has two motivations: firstly, to compare the Digital Surface Models (DSM) derived by passive (digital camera) and by active (terrestrial laser scanner) remote sensing systems when applied to specific architectural objects, and secondly, to test how well the Gaussian classic statistics, with its Least Squares principle, adapts to data sets where asymmetrical gross errors may appear and whether this approach should be changed for a non-parametric one. The field of geomatic technology automation is immersed in a high demanding competition in which any innovation by one of the contenders immediately challenges the opponents to propose a better improvement. Nowadays, we seem to be witnessing an improvement of terrestrial photogrammetry and its integration with computer vision to overcome the performance limitations of laser scanning methods. Through this contribution some of the issues of this “technological race” are examined from the point of view of photogrammetry. A new software is introduced and an experimental test is designed, performed and assessed to try to cast some light on this thrilling match. For the case considered in this study, the results show good agreement between both sensors, despite considerable asymmetry. This asymmetry suggests that the standard Normal parameters are not adequate to assess this type of data, especially when accuracy is of importance. In this case, standard deviation fails to provide a good estimation of the results, whereas the results obtained for the Median Absolute Deviation and for the Biweight Midvariance are more appropriate measures. PMID:25196104

  1. Active and passive microwave measurements of soil moisture in FIFE

    SciTech Connect

    Wang, J.R. ); Gogineni, S.P.; Ampe, J. )

    1992-11-30

    This work is part of the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE), an international land-surface-atmosphere experiment aimed at improving the way climate models represent energy, water, heat, and carbon exchanges, and improving the utilization of satellite based remote sensing to monitor such parameters. This paper reports on the application of active and passive microwave measurement systems to the simultaneous determination of soil moisture. These systems have been tested on common targets very few times. Here C and X band scatterometer data from a helicopter base is compared with L band push broom microwave radiometer (PBMR) data taken from the NASA C-130 aircraft. The regions sampled over FIFE encompass areas with different surface treatments. The scatterometers proved to be sensitive to soil moisture over most of the areas studied, while the radiometer lost sensitivity in regions which had been unburned for years, and which thus had substantial dead organic accumulation. The correlation of soil moisture and backscattered signal was observed to increase with off normal angles.

  2. A Comparison between Lightning Activity and Passive Microwave Measurements

    NASA Technical Reports Server (NTRS)

    Kevin, Driscoll T.; Hugh, Christian J.; Goodman, Steven J.

    1999-01-01

    A recent examination of data from the Lightning Imaging Sensor (LIS) and the TRMM Microwave Imager (TMI) suggests that storm with the highest frequency of lightning also possess the most pronounced microwave scattering signatures at 37 and 85 GHz. This study demonstrates a clear dependence between lightning and the passive microwave measurements, and accentuates how direct the relationship really is between cloud ice and lightning activity. In addition, the relationship between the quantity of ice content and the frequency of lightning (not just the presence of lightning) , is consistent throughout the seasons in a variety of regimes. Scatter plots will be presented which show the storm-averaged brightness temperatures as a function of the lightning density of the storms (L/Area) . In the 85 GHz and 37 GHz scatter plots, the brightness temperature is presented in the form Tb = k1 x log10(L/Area) + k2, where the slope of the regression, k1, is 58 for the 85 GHz relationship and 30.7 for the 37 GHz relationship. The regression for both these fits showed a correlation of 0.76 (r2 = 0.58), which is quite promising considering the simple procedure used to make the comparisons, which have not yet even been corrected for the view angle differences between the instruments, or the polarization corrections in the microwave imager.

  3. Realistic Instrumentation Platform for Active and Passive Optical Remote Sensing.

    PubMed

    Brydegaard, Mikkel; Merdasa, Aboma; Gebru, Alem; Jayaweera, Hiran; Svanberg, Sune

    2016-02-01

    We describe the development of a novel versatile optical platform for active and passive remote sensing of environmental parameters. Applications include assessment of vegetation status and water quality. The system is also adapted for ecological studies, such as identification of flying insects including agricultural pests. The system is based on two mid-size amateur astronomy telescopes, continuous-wave diode lasers at different wavelengths ranging from violet to the near infrared, and detector facilities including quadrant photodiodes, two-dimensional and line scan charge-coupled device cameras, and a compact digital spectrometer. Application examples include remote Ramanlaser-induced fluorescence monitoring of water quality at 120 m distance, and insect identification at kilometer ranges using the recorded wing beat frequency and its spectrum of overtones. Because of the low cost this developmental platform is very suitable for advanced research projects in developing countries and has, in fact, been multiplied during hands-on workshops and is now being used by a number of groups at African universities. PMID:26772187

  4. Passive and active optical fibers for space and terrestrial applications

    NASA Astrophysics Data System (ADS)

    Alam, Mansoor; Abramczyk, Jaroslaw; Farroni, Julia; Manyam, Upendra; Guertin, Douglas

    2006-08-01

    Being the new frontier of science and technology, as the near earth space begins to attract attention, low cost and rapidly deployable earth observation satellites are becoming more important. Among other things these satellites are expected to carry out missions in the general areas of science and technology, remote sensing, national defense and telecommunications. Except for critical missions, constraints of time and money practically mandate the use of commercial-off-the-shelf (COTS) components as the only viable option. The near earth space environment (~50-50000 miles) is relatively hostile and among other things components/devices/systems are exposed to ionizing radiation. Photonic devices/systems are and will continue to be an integral part of satellites and their payloads. The ability of such devices/systems to withstand ionizing radiation is of extreme importance. Qualification of such devices/systems is time consuming and very expensive. As a result, manufacturers of satellites and their payloads have started to ask for radiation performance data on components from the individual vendors. As an independent manufacturer of both passive and active specialty silica optical fibers, Nufern is beginning to address this issue. Over the years, Nufern has developed fiber designs, compositions and processes to make radiation hard fibers. Radiation performance data (both gamma and proton) of a variety of singlemode (SM), multimode (MM), polarization maintaining (PM) and rare-earth doped (RED) fibers that find applications in space environment are presented.

  5. Passive and active launch vibration studies in the LVIS program

    NASA Astrophysics Data System (ADS)

    Edberg, Donald L.; Bartos, Bruce; Goodding, James C.; Wilke, Paul S.; Davis, Torey

    1998-06-01

    A U.S. Air Force-sponsored team consisting of Boeing (formerly McDonnell Douglas), Honeywell Satellite Systems, and CSA Engineering has developed technology to reduce the vibration felt by an isolated payload during launch. Spacecraft designers indicate that a launch vibration isolation system (LVIS) could provide significant cost benefits in payload design, testing, launch, and lifetime. This paper contains developments occurring since those reported previously. Simulations, which included models of a 6,500 pound spacecraft, an isolating payload attach fitting (PAF) to replace an existing PAF, and the Boeing Delta II launch vehicle, were used to generate PAF performance requirements for the desired levels of attenuation. Hardware was designed to meet the requirements. The isolating PAF concept replaces portions of a conventional metallic fitting with hydraulic- pneumatic struts featuring a unique hydraulic cross-link feature that stiffens under rotation to meet rocking restrictions. The pneumatics provide low-stiffness longitudinal support. Two demonstration isolating PAF struts were designed, fabricated and tested to determine their stiffness and damping characteristics and to verify the performance of the hydraulic crosslink concept. Measurements matched analytical predictions closely. An active closed-loop control system was simulated to assess its potential isolation performance. A factor of 100 performance increase over the passive case was achieved with minor weight addition and minimal power consumption.

  6. Characterization of the passive component of force enhancement following active stretching of skeletal muscle.

    PubMed

    Herzog, W; Schachar, R; Leonard, T R

    2003-10-01

    The mechanisms causing the steady-state force enhancement following active skeletal muscle stretching are not well understood. Recently, we found direct evidence that part of the force enhancement is associated with the engagement of a passive component. In this study, we reproduced the conditions that give consistent passive force enhancement and evaluated the mechanical properties of this passive force enhancement so as to gain insight into its source. The three primary results were that (1). the passive force enhancement is long lasting (>25 s), (2). passive force enhancement was reduced in a dose-dependent manner by the amount of shortening preceding active muscle stretching, and (3). passive force enhancement could be abolished 'instantaneously' by shortening-stretching the passive muscle by an amount equivalent to the active stretch magnitude. Together with the remaining results, we conclude that the source of the passive force enhancement must be arranged in parallel with the contractile force, it must consist of a viscoelastic molecular spring whose stiffness characteristic can be reset by shortening, and it must have a characteristic length that is governed by the length of the contractile components, possibly the sarcomeres. Based on these results, the molecular spring titin emerges as a possible candidate for the passive component of the steady-state force enhancement observed in this and previous studies.

  7. Achieving Lights-Out Operation of SMAP Using Ground Data System Automation

    NASA Technical Reports Server (NTRS)

    Sanders, Antonio

    2013-01-01

    The approach used in the SMAP ground data system to provide reliable, automated capabilities to conduct unattended operations has been presented. The impacts of automation on the ground data system architecture were discussed, including the three major automation patterns identified for SMAP and how these patterns address the operations use cases. The architecture and approaches used by SMAP will set the baseline for future JPL Earth Science missions.

  8. Active and passive immunisation against respiratory syncytial virus.

    PubMed

    Zambon, M

    1999-01-01

    RSV is a major cause of respiratory illness in infants under 2 years of age. Evidence is accumulating that it is also underestimated as a cause of respiratory infection in adults, the elderly and immunocompromised individuals. Active interventions to control the impact of RSV infection have been hampered by a lack of understanding of the immune response to RSV in different age groups. A number of different strategies for developing RSV vaccines have been pursued, including live attenuated vaccines, genetically engineered live and subunit vaccines and peptide vaccines with varying degrees of success. The target populations for RSV vaccines include infants, the elderly and women of childbearing age, but the efficacy of different vaccines may differ according to age. Desirable immune responses and immune correlates of protection to RSV in humans remain uncertain and determining these is critical for introduction of any vaccines. Prophylaxis and treatment of RSV in infants using human immunoglobulin containing high titres of RSV specific neutralising antibody (RSV-Ig) has shown limited success in different infant populations. Prophylaxis of premature infants with RSV-Ig, particularly those with bronchopulmonary dysplasia, has demonstrated limited clinical efficacy against RSV. In contrast, there are significant safety concerns for use of this preparation for prophylaxis in infants with congenital heart disease and no demonstrable efficacy in treatment of RSV disease in healthy infants. The cost of the preparation will limit use to highly selected infant groups. Production of humanized monoclonal antibodies to RSV offers another potential passive immunotherapy intervention for RSV, with increased specific activity and reduced side effects, although its use remains experimental. PMID:10578118

  9. Active and Passive RF Components for High-Power Systems

    NASA Astrophysics Data System (ADS)

    Tantawi, Sami G.; Nantista, Christopher D.

    2002-08-01

    In recent years, R&D for pulse compression and power distribution systems for the Next Linear Collider has led to the invention of many novel rf components, some of which must handle up to 600 MW of pulsed power at X-band. These include passive waveguide components, active switch designs, and non-reciprocal devices. Among the former is a class of multi-moded, highly efficient rf components based on planar geometries with overmoded rectangular ports. Multi-moding allows us, by means of input phasing, to direct power to different locations through the same waveguide. Planar symmetry allows the height to be increased to improve power handling capacity. Features that invite breakdown, such as coupling slots, irises and H-plane septa, are avoided. This class includes hybrids, directional couplers, an eight-port superhybrid/dual-mode launcher, a mode-selective extractor, mode-preserving bends, a rectangular mode converter, and mode-mixers. We are able to utilize such rectangular waveguide components in systems incorporating low-loss, circular waveguide delay lines by means of specially designed tapers that efficiently transform multiple rectangular waveguide modes into their corresponding circular waveguide modes, specifically TE10 and TE20 into circular TE11 and TE01. These extremely compact tapers can replace well-known mode converters such as the Marie type. Another component, a reflective TE01-TE02 mode converter in circular waveguide, allows us to double the delay in reflective or resonant delay lines. Ideas for multi-megawatt active components, such as switches, have also been pursued. Power-handling capacity for these is increased by making them also highly overmoded. We present a design methodology for active rf magnetic components which are suitable for pulse compression systems of future X-band linear colliders. We also present an active switch based on a PIN diode array. This component comprises an array of active elements arranged so that the electric fields

  10. On the identification of representative in situ soil moisture monitoring stations for the validation of SMAP soil moisture products in Australia

    NASA Astrophysics Data System (ADS)

    Yee, Mei Sun; Walker, Jeffrey P.; Monerris, Alessandra; Rüdiger, Christoph; Jackson, Thomas J.

    2016-06-01

    The high spatio-temporal variability of soil moisture complicates the validation of remotely sensed soil moisture products using in situ monitoring stations. Therefore, a standard methodology for selecting the most representative stations for the purpose of validating satellites and land surface models is essential. Based on temporal stability and geostatistical studies using long-term soil moisture records, intensive ground measurements and airborne soil moisture products, this study investigates the representativeness of soil moisture monitoring stations within the Yanco study area for the validation of NASA's Soil Moisture Active Passive (SMAP) products at 3 km for radar, 9 km for radar-radiometer and 36 km for radiometer pixels. This resulted in the identification of a number of representative stations according to the different scales. Although the temporal stability method was found to be suitable for identifying representative stations, stations based on the mean relative difference (MRD) were not necessarily the most representative of the areal average. Moreover, those identified from standard deviation of the relative difference (SDRD) may be dry-biased. It was also found that in the presence of heterogeneous land use, stations should be weighted based on proportions of agricultural land. Airborne soil moisture products were also shown to provide useful a priori information for identifying representative locations. Finally, recommendations are made regarding the design of future networks for satellite validation, and specifically the most representative stations for the Yanco area.

  11. TMS reveals a direct influence of spinal projections from human SMAp on precise force production.

    PubMed

    Entakli, Jonathan; Bonnard, Mireille; Chen, Sophie; Berton, Eric; De Graaf, Jozina B

    2014-01-01

    The corticospinal (CS) system plays an important role in fine motor control, especially in precision grip tasks. Although the primary motor cortex (M1) is the main source of the CS projections, other projections have been found, especially from the supplementary motor area proper (SMAp). To study the characteristics of these CS projections from SMAp, we compared muscle responses of an intrinsic hand muscle (FDI) evoked by stimulation of human M1 and SMAp during an isometric static low-force control task. Subjects were instructed to maintain a small cursor on a target force curve by applying a pressure with their right precision grip on a force sensor. Neuronavigated transcranial magnetic stimulation was used to stimulate either left M1 or left SMAp with equal induced electric field values at the defined cortical targets. The results show that the SMAp stimulation evokes reproducible muscle responses with similar latencies and amplitudes as M1 stimulation, and with a clear and significant shorter silent period. These results suggest that (i) CS projections from human SMAp are as rapid and efficient as those from M1, (ii) CS projections from SMAp are directly involved in control of the excitability of spinal motoneurons and (iii) SMAp has a different intracortical inhibitory circuitry. We conclude that human SMAp and M1 both have direct influence on force production during fine manual motor tasks. PMID:24164635

  12. 26 CFR 1.469-2T - Passive activity loss (temporary).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... building for three years preceding the sale and at all times during that period used seven floors of the... TAX (CONTINUED) INCOME TAXES (CONTINUED) Taxable Year for Which Deductions Taken § 1.469-2T Passive... amount of the taxpayer's passive activity loss for the taxable year for purposes of section 469 and...

  13. 26 CFR 1.469-2T - Passive activity loss (temporary).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... building for three years preceding the sale and at all times during that period used seven floors of the... TAX (CONTINUED) INCOME TAXES (CONTINUED) Taxable Year for Which Deductions Taken § 1.469-2T Passive... amount of the taxpayer's passive activity loss for the taxable year for purposes of section 469 and...

  14. 26 CFR 1.469-2T - Passive activity loss (temporary).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... building for three years preceding the sale and at all times during that period used seven floors of the... TAX (CONTINUED) INCOME TAXES (CONTINUED) Taxable Year for Which Deductions Taken § 1.469-2T Passive... amount of the taxpayer's passive activity loss for the taxable year for purposes of section 469 and...

  15. Integrated passive/active vibration absorber for multi-story buildings

    NASA Technical Reports Server (NTRS)

    Lee-Glauser, Gina J.; Ahmadi, Goodarz; Horta, Lucas G.

    1995-01-01

    Passive isolator, active vibration absorber, and an integrated passive/active (hybrid) control are studied for their effectiveness in reducing structural vibration under seismic excitations. For the passive isolator, a laminated rubber bearing base isolator which has been studied and used extensively by researchers and seismic designers is considered. An active vibration absorber concept, which can provide guaranteed closed-loop stability with minimum knowledge of the controlled system, is used to reduce the passive isolator displacement and to suppress the top floor vibration. A three-story building model is used for the numerical simulation. The performance of an active vibration absorber and a hybrid vibration controller in reducing peak structural responses is compared with the passively isolated structural response and with absence of vibration control systems under the N00W component of El Centro 1940 and N90W component of the Mexico City earthquake excitation records. The results show that the integrated passive/active vibration control system is most effective in suppressing the peak structural acceleration for the El Centro 1940 earthquake when compared with the passive or active vibration absorber alone. The active vibration absorber, however, is the only system that suppresses the peak acceleration of the structure for the Mexico City 1985 earthquake.

  16. Aerosol identification using a hybrid active/passive system

    NASA Astrophysics Data System (ADS)

    D'Amico, Francis M.; Moon, Raphael P.; Davidson, Charles E.

    2005-08-01

    Recent experimental work has shown that passive systems such as hyperspectral FTIR and frequency-tunable IR cameras have application in detection of biological aerosols. This provided the motivation for a new detection technique, which we call Aerosol Ranging Spectroscopy (ARS), whereby a scattering LIDAR is used to augment passive spectrometer data to determine the location and optical depth of the aerosol plume. When the two systems are co-aligned or boresighted, the hybrid data product provides valuable enhancements for signal exploitation of the passive spectral data. This paper presents the motivation and theoretical basis for the ARS technique. A prototype implementation of an ARS system will also be described, along with preliminary results from recent outdoor field experiments.

  17. The Significance of Turning Passive Into Active in Control Mastery Theory

    PubMed Central

    FOREMAN, STEVEN A.

    1996-01-01

    Turning passive into active was first described by Freud but was later given expanded importance by Weiss. This new conceptualization of turning passive into active as an interpersonal communication and test has made a major contribution to the clinical treatment of difficult patients. This article reviews "control mastery" theory and puts its notion of passive-into-active testing into perspective with regard to Freud’s original conception as well as other conceptions, such as identification with the aggressor and projective identification. Formulation and the treatment of patients are illustrated with clinical examples. PMID:22700271

  18. Numerical simulation study on active and passive hydroforming process optimization of box shaped part

    NASA Astrophysics Data System (ADS)

    Zeng, Y. P.; Dong, J. L.; He, T. D.; Wang, B.

    2016-08-01

    Low qualified rate and inferior quality frequently occurring in the general deep drawing process of a certain box-shaped part, now use hydroforming to optimize forming process, in order to study the effect of hydroforming for improving the quality and formability, purposed five process schemes: general deep drawing, active hydroforming, passive hydroforming, general deep drawing combined with active hydroforming, passive combined with active hydroforming. Each process was simulated by finite element simulation and results were analysed. The results indicate the passive combined with active hydroforming is the best scheme which can obtain smallest thickness thinning and satisfactory formability, then optimized hydroforming pressure, blank holder force subsequently by adjust the simulation parameters. Research result proves that active/passive hydroforming is a new method for complex parts forming.

  19. Regulation of adult cardiocyte growth: effects of active and passive mechanical loading

    NASA Technical Reports Server (NTRS)

    Decker, M. L.; Janes, D. M.; Barclay, M. M.; Harger, L.; Decker, R. S.

    1997-01-01

    Fluctuations in hemodynamic load have been documented to modulate contractile protein turnover and myofibrillar structure in the heart; however, the relative importance of active and passive loading in regulating adult cardiocyte growth remains unresolved. To address this issue at the cellular level, adult feline cardiocytes were cultured either on Silastic membranes or plastic surfaces. Cardiocyte-laden membranes were stretched 10% of their rest length to enhance passive loading, whereas heart cells cultured on plastic or Silastic were field stimulated at 1 Hz to mimic active loading. Turnover of contractile proteins and structural integrity of the contractile-cytoskeletal apparatus were monitored for periods ranging from 4 to 72 h. Active and passive loading elevated contractile protein synthesis nearly equally (approximately 50%) and promoted the attachment of remodeled myofibrils to vinculin-positive focal contacts and/or costameres during the first 24 h of loading. Thereafter, rates of contractile protein synthesis returned to control values in passively stretched heart cells but remained elevated in field-stimulated cultures. The fractional rate of growth was increased significantly (approximately 8%/day) in electrically paced cells, whereas in passively stretched cardiocytes the growth rate rose only modestly (approximately 2%/day). Changes in the rate of myocyte growth appeared more closely correlated with the development of focal contacts and myofibril remodeling than with changes in myofibrillar protein turnover per se. 2,3-Butanedione monoxime, nifedipine, and, to a lesser extent, ryanodine blocked field-stimulated contractile protein synthesis and myofibrillar remodeling but had no impact on protein turnover or myofibril reassembly in passively loaded cardiocytes. The results of these experiments imply that both active and passive loading stimulate contractile protein turnover and myofibril remodeling, but the generation of active tension accelerates

  20. Modeling Chemical Detection Sensitivities of Active and Passive Remote Sensing Systems

    SciTech Connect

    Scharlemann, E T

    2003-07-28

    During nearly a decade of remote sensing programs under the auspices of the U. S. Department of Energy (DOE), LLNL has developed a set of performance modeling codes--called APRS--for both Active and Passive Remote Sensing systems. These codes emphasize chemical detection sensitivity in the form of minimum detectable quantities with and without background spectral clutter and in the possible presence of other interfering chemicals. The codes have been benchmarked against data acquired in both active and passive remote sensing programs at LLNL and Los Alamos National Laboratory (LANL). The codes include, as an integral part of the performance modeling, many of the data analysis techniques developed in the DOE's active and passive remote sensing programs (e.g., ''band normalization'' for an active system, principal component analysis for a passive system).

  1. Active and passive multispectral scanner for earth resources applications: An advanced applications flight experiment

    NASA Technical Reports Server (NTRS)

    Hasell, P. G., Jr.; Peterson, L. M.; Thomson, F. J.; Work, E. A.; Kriegler, F. J.

    1977-01-01

    The development of an experimental airborne multispectral scanner to provide both active (laser illuminated) and passive (solar illuminated) data from a commonly registered surface scene is discussed. The system was constructed according to specifications derived in an initial programs design study. The system was installed in an aircraft and test flown to produce illustrative active and passive multi-spectral imagery. However, data was not collected nor analyzed for any specific application.

  2. Enhanced active aluminum content and thermal behaviour of nano-aluminum particles passivated during synthesis using thermal plasma route

    NASA Astrophysics Data System (ADS)

    Mathe, Vikas L.; Varma, Vijay; Raut, Suyog; Nandi, Amiya Kumar; Pant, Arti; Prasanth, Hima; Pandey, R. K.; Bhoraskar, Sudha V.; Das, Asoka K.

    2016-04-01

    Here, we report synthesis and in situ passivation of aluminum nanoparticles using thermal plasma reactor. Both air and palmitc acid passivation was carried out during the synthesis in the thermal plasma reactor. The passivated nanoparticles have been characterized for their structural and morphological properties using X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. In order to understand nature of passivation vibrational spectroscopic analysis have been carried out. The enhancement in active aluminum content and shelf life for a palmitic acid passivated nano-aluminum particles in comparison to the air passivated samples and commercially available nano Al powder (ALEX) has been observed. Thermo-gravimetric analysis was used to estimate active aluminum content of all the samples under investigation. In addition cerimetric back titration method was also used to estimate AAC and the shelf life of passivated aluminum particles. Structural, microstructural and thermogravomateric analysis of four year aged passivated sample also depicts effectiveness of palmitic acid passivation.

  3. The influence of active and passive smoking on the cardiorespiratory fitness of adults

    PubMed Central

    2014-01-01

    Background The aim of this study was to analyze the influence of active and passive smoking on cardiorespiratory responses in asymptomatic adults during a sub-maximal-exertion incremental test. Methods The participants (n = 43) were divided into three different groups: active smokers (n = 14; aged 36.5 ± 8 years), passive smokers (n = 14; aged 34.6 ± 11.9 years) and non-smokers (n = 15; aged 30 ± 8.1 years). They all answered the Test for Nicotine Dependence and underwent anthropometric evaluation, spirometry and ergospirometry according to the Bruce Treadmill Protocol. Results VO2max differed statistically between active and non-smokers groups (p < 0.001) and between non-smokers and passive group (p=0.022). However, there was no difference between the passive and active smokers groups (p=0.053). Negative and significant correlations occurred between VO2max and age (r = - 0.401, p = 0.044), percentage of body fat (r = - 0.429, p = 0.011), and waist circumference (WC) (r = - 0.382, p = 0.025). Conclusion VO2max was significantly higher in non-smokers compared to active smokers and passive smokers. However, the VO2max of passive smokers did not differ from active smokers. PMID:25009739

  4. [ACTIVE AND PASSIVE DISCRIMINATION OF MOVING SOUNDS: RHYTHMIC ACTIVITY OF HUMAN BRAIN].

    PubMed

    Shestopalova, L B; Petropavlovskaia, E A; Nikitin, N I; Vaitulevich, S Ph

    2015-12-01

    The spectral dynamics of the EEG rhythmicity during active and passive discrimination of stationary and moving sound stimuli presented according to the oddball paradigm were investigated. Standard stimuli represented stationary midline sounds. Deviant stimuli simulated smooth and stepwise sound source motion (to the left/right from head midline) produced by linear and stepwise changes of interaural time delay. Significant changes of the brain oscillations were found in the frequency range of 3-30 Hz. The dynamics of the moving deviant stimuli (smooth vs. stepwise) had greater impact on theta-rhythm power in active listening conditions: a stronger theta-power increase was evoked by the stepwise sound motion as compared to smooth motion. Significant increase in theta-power was also observed with rightward sound displacement as compared to leftward displacements. Active deviant discrimination reduced alpha-power (8-11 Hz) mostly during smooth deviant motion. The power increase of lower alpha-oscillations (12-15 Hz) was stronger with step- wise motion than with smooth motion of deviants. The interhemispheric asymmetry of beta-power decrease in active conditions (as compared to passive) was found in the whole beta-range. The sup- pression of beta-power was stronger at the right hemisphere than at the midline or left hemisphere and showed no dependence on spatial properties of the deviant stimuli. This asymmetry may be related to selective attention to task-relevant sounds and with preparation to motor response. Generally, active auditory discrimination resulted in stronger deviant-related changes of the wide-ranged EEG spectral power than passive discrimination with attentional tuning to task-irrelevant stimuli.

  5. When passives are easier than actives: two case studies of aphasic comprehension.

    PubMed

    Druks, J; Marshall, J C

    1995-06-01

    We outline a range of previous theoretical accounts of agrammatic comprehension in patients with Broca's aphasia. Specific attention is paid to patterns of preserved and impaired understanding of reversible actives and passives. We note that no prior account will allow for the existence of patients who show better comprehension of passives than actives. In three experiments, we compare and contrast the performance of two patients whose syntactic comprehension ability is in complementary distribution. The first patient (M.H.) performs well on simple actives, active questions, and active existentials, but is below chance on their corresponding passives. The second patient (B.M.) is at chance on simple actives, active questions and active existentials while scoring significantly above chance on their respective passives. We interpret both patterns of response in terms of the distinction drawn by Case theory between structural and inherent Case. The first patient's grammar cannot assign either structural or inherent Case and she must accordingly apply a non-linguistic linear strategy to assign thematic roles in all sentences. The second patient (B.M.) has a specific impairment of structural Case; he can accordingly not interpret actives (where Case is assigned configurationally) but can interpret passives (where Case is assigned lexically). PMID:7634762

  6. Active and realistic passive marijuana exposure tested by three immunoassays and GC/MS in urine

    SciTech Connect

    Mule, S.J.; Lomax, P.; Gross, S.J.

    1988-05-01

    Human urine samples obtained before and after active and passive exposure to marijuana were analyzed by immune kits (Roche, Amersham, and Syva) and gas chromatography/mass spectrometry (GC/MS). Seven of eight subjects were positive for the entire five-day test period with one immune kit. The latter correlated with GC/MS in 98% of the samples. Passive inhalation experiments under conditions likely to reflect realistic exposure resulted consistently in less than 10 ng/mL of cannabinoids. The 10-100-ng/mL cannabinoid concentration range essential for detection of occasional and moderate marijuana users is thus unaffected by realistic passive inhalation.

  7. Curvature-induced activation of a passive tracer in an active bath

    NASA Astrophysics Data System (ADS)

    Mallory, S. A.; Valeriani, C.; Cacciuto, A.

    2014-09-01

    We use numerical simulations to study the motion of a large asymmetric tracer immersed in a low-density suspension of self-propelled particles in two dimensions. Specifically, we analyze how the curvature of the tracer affects its translational and rotational motion in an active environment. We find that even very small amounts of curvature are sufficient for the active bath to impart directed motion to the tracer, which results in its effective activation. We propose simple scaling arguments to characterize this induced activity in terms of the curvature of the tracer and the strength of the self-propelling force. Our results suggest new ways of controlling the transport properties of passive tracers in an active medium by carefully tailoring their geometry.

  8. Curvature-induced activation of a passive tracer in an active bath.

    PubMed

    Mallory, S A; Valeriani, C; Cacciuto, A

    2014-09-01

    We use numerical simulations to study the motion of a large asymmetric tracer immersed in a low-density suspension of self-propelled particles in two dimensions. Specifically, we analyze how the curvature of the tracer affects its translational and rotational motion in an active environment. We find that even very small amounts of curvature are sufficient for the active bath to impart directed motion to the tracer, which results in its effective activation. We propose simple scaling arguments to characterize this induced activity in terms of the curvature of the tracer and the strength of the self-propelling force. Our results suggest new ways of controlling the transport properties of passive tracers in an active medium by carefully tailoring their geometry. PMID:25314448

  9. Active and Passive Fatigue in Simulated Driving: Discriminating Styles of Workload Regulation and Their Safety Impacts

    PubMed Central

    Saxby, Dyani J.; Matthews, Gerald; Warm, Joel S.; Hitchcock, Edward M.; Neubauer, Catherine

    2015-01-01

    Despite the known dangers of driver fatigue, it is a difficult construct to study empirically. Different forms of task-induced fatigue may differ in their effects on driver performance and safety. Desmond and Hancock (2001) defined active and passive fatigue states that reflect different styles of workload regulation. In 2 driving simulator studies we investigated the multidimensional subjective states and safety outcomes associated with active and passive fatigue. Wind gusts were used to induce active fatigue, and full vehicle automation to induce passive fatigue. Drive duration was independently manipulated to track the development of fatigue states over time. Participants were undergraduate students. Study 1 (N = 108) focused on subjective response and associated cognitive stress processes, while Study 2 (N = 168) tested fatigue effects on vehicle control and alertness. In both studies the 2 fatigue manipulations produced different patterns of subjective response reflecting different styles of workload regulation, appraisal, and coping. Active fatigue was associated with distress, overload, and heightened coping efforts, whereas passive fatigue corresponded to large-magnitude declines in task engagement, cognitive underload, and reduced challenge appraisal. Study 2 showed that only passive fatigue reduced alertness, operationalized as speed of braking and steering responses to an emergency event. Passive fatigue also increased crash probability, but did not affect a measure of vehicle control. Findings support theories that see fatigue as an outcome of strategies for managing workload. The distinction between active and passive fatigue is important for assessment of fatigue and for evaluating automated driving systems which may induce dangerous levels of passive fatigue. PMID:24041288

  10. Rapid increases in ventilation accompany the transition from passive to active movement.

    PubMed

    Bell, Harold J; Duffin, James

    2006-06-01

    We used a novel movement transition technique to look for evidence of a rapid onset drive to breathe related to the active component of exercise in humans. Ten volunteers performed the following transitions in a specially designed tandem exercise chair apparatus: rest to passive movement, passive to active movement, and rest to active movement. The transition from rest to active exercise was accompanied by an immediate increase in ventilation, as was the transition from rest to passive leg movement (Delta = 6.06 +/- 1.09 l min(-1), p < 0.001 and Delta = 3.30 +/- 0.57 l min(-1), p = 0.002, respectively). When subjects actively assumed the leg movements, ventilation again increased immediately and significantly (Delta = 2.55 +/- 0.52 l min(-1), p = 0.032). Ventilation at the first point of active exercise was the same when started either from rest or from a background of passive leg movement (p = 1.00). We conclude that the use of a transition from passive to active leg movements in humans recruits a ventilatory drive related to the active component of exercise, and this can be discerned as a rapid increase in breathing.

  11. Pre-launch Research to Integrate NASA SMAP Soil Moisture and Freeze/Thaw State Products in Applications

    NASA Astrophysics Data System (ADS)

    Moran, S. M.; Bilair, S.; Isaksen, L.; de Rosnay, P.; Zhan, X.; Ghedira, H.; Yang, Z.; Mueller, R.; Ines, A. M.; Zebiak, S. E.; Champagne, C.; Brown, M.; Escobar, V.; Weiss, B.

    2011-12-01

    The SMAP Mission is currently planned for launch in late 2014 to provide global measurements of soil moisture and freeze/thaw state. For mission planning, a Testbed Facility is in place to test software that will be used to automatically generate the science data products once SMAP is in orbit. Early distribution of a subset of these testbed data products and calibration/validation data sets to SMAP "Early Adopters" has enabled pre-launch applications research. Early Adopters are those groups who have a direct need for SMAP-like soil moisture or freeze/thaw data, and who are planning to apply their own resources to demonstrate the utility of SMAP data for their particular system or model. A set of 7 SMAP Early Adopters were selected in March 2011, with applications including weather forecasts, food security and mapping dust emissions [http://smap.jpl.nasa.gov/files/smap2/adopter1.pdf]. Research projects will be completed with quantitative metrics prior to the launch of SMAP. The feedback from these projects is providing a fundamental understanding of how SMAP data products can be scaled and integrated into hydrologic applications to improve decision-making. A second round of selections for SMAP Early Adopters is planned for February 2012.

  12. Passive and active protection from ionizing radiation in space: new activities and perspectives.

    NASA Astrophysics Data System (ADS)

    Spillantini, Piero

    Very intense Solar Cosmic Ray (SCR) events are rare, but not predictable, and can be lethal to a not protected crew in deep space. A ‘life saving’ system must therefore be provided also in short duration manned missions. Passive and active ‘life saving’ system will be revised and discussed. Galactic Cosmic Rays (GCR) instead flow continuously, have a moderate intensity but the accumulation of their effects can have consequences to human health in long duration (≥one year) mission in deep space, and a ‘health saving’ system should be provided. Passive systems are not applicable and recourse has to be made to active systems based on powerful magnetic fields for deviating particles from the habitat where crew members live and work. The activities of last decade are revised and two scenarios are evaluated and discussed: (1) magnetic toroidal systems for mitigating the radiation dose in the relatively large (≅100m3) habitat of interplanetary spaceships; (2) very large magnetic systems for protecting a large habitat (≈500m3) of an inhabited station that should operate for many decades in deep space. Effectiveness, complexity, involved engineering problems and perspectives are outlined and discussed for both the scenarios. They are nowadays studied and evaluated by a cooperative project supported by the European Union that will be illustrated in a dedicated talk.

  13. A Science Data System Approach for the SMAP Mission

    NASA Technical Reports Server (NTRS)

    Woollard, David; Kwoun, Oh-ig; Bicknell, Tom; West, Richard; Leung, Kon

    2009-01-01

    Though Science Data System (SDS) development has not traditionally been part of the mission concept phase, lessons learned and study of past Earth science missions indicate that SDS functionality can greatly benefit algorithm developers in all mission phases. We have proposed a SDS approach for the SMAP Mission that incorporates early support for an algorithm testbed, allowing scientists to develop codes and seamlessly integrate them into the operational SDS. This approach will greatly reduce both the costs and risks involved in algorithm transitioning and SDS development.

  14. Active-passive gradient shielding for MRI acoustic noise reduction.

    PubMed

    Edelstein, William A; Kidane, Tesfaye K; Taracila, Victor; Baig, Tanvir N; Eagan, Timothy P; Cheng, Yu-Chung N; Brown, Robert W; Mallick, John A

    2005-05-01

    An important source of MRI acoustic noise-magnet cryostat warm-bore vibrations caused by eddy-current-induced forces-can be mitigated by a passive metal shield mounted on the outside of a vibration-isolated, vacuum-enclosed shielded gradient set. Finite-element (FE) calculations for a z-gradient indicate that a 2-mm-thick Cu layer wrapped on the gradient assembly can decrease mechanical power deposition in the warm bore and reduce warm-bore acoustic noise production by about 25 dB. Eliminating the conducting warm bore and other magnet parts as significant acoustic noise sources could lead to the development of truly quiet, fully functioning MRI systems with noise levels below 70 dB.

  15. A Prototype Land Information Sensor Web: Design, Implementation and Implication for the SMAP Mission

    NASA Astrophysics Data System (ADS)

    Su, H.; Houser, P.; Tian, Y.; Geiger, J. K.; Kumar, S. V.; Gates, L.

    2009-12-01

    developed and it is the very first sensor web framework developed especially for the land surface studies. Synthetic experiments based on the LISW-SOA and the virtual sensor web provide a controlled environment in which to examine the end-to-end performance of the prototype, the impact of various sensor web design trade-offs and the eventual value of sensor webs for a particular prediction or decision support. In this paper, the design, implementation of the LISW-SOA and the implication for the Soil Moisture Active and Passive (SMAP) mission is presented. Particular attention is focused on examining the relationship between the economic investment on a sensor web (space and air borne, ground based) and the accuracy of the model predicted soil moisture, which can be achieved by using such sensor observations. The Study of Virtual Land Information Sensor Web (LISW) is expected to provide some necessary a priori knowledge for designing and deploying the next generation Global Earth Observing System of systems (GEOSS).

  16. Console video games, postural activity, and motion sickness during passive restraint.

    PubMed

    Chang, Chih-Hui; Pan, Wu-Wen; Chen, Fu-Chen; Stoffregen, Thomas A

    2013-08-01

    We examined the influence of passive restraint on postural activity and motion sickness in individuals who actively controlled a potentially nauseogenic visual motion stimulus (a driving video game). Twenty-four adults (20.09 ± 1.56 years; 167.80 ± 7.94 cm; 59.02 ± 9.18 kg) were recruited as participants. Using elastic bands, standing participants were passively restrained at the head, shoulders, hips, and knees. During restraint, participants played (i.e., controlled) a driving video game (a motorcycle race), for 50 min. During game play, we recorded the movement of the head and torso, using a magnetic tracking system. Following game play, participants answered a forced choice, yes/no question about whether they were motion sick, and were assigned to sick and well groups on this basis. In addition, before and after game play, participants completed the Simulator Sickness Questionnaire, which provided numerical ratings of the severity of individual symptoms. Five of 24 participants (20.83 %) reported motion sickness. Participants moved despite being passively restrained. Both the magnitude and the temporal dynamics of movement differed between the sick and well groups. The results show that passive restraint of the body can reduce motion sickness when the nauseogenic visual stimulus is under participants' active control and confirm that motion sickness is preceded by distinct patterns of postural activity even during passive restraint.

  17. Data Management System Reuse for Visualization of JPL's SMAP Project

    NASA Astrophysics Data System (ADS)

    Alarcon, C.; Huang, T.; Roberts, J. T.; Rodriguez, J. D.; Quach, N. T.; De Cesare, C.; Hall, J. R.

    2015-12-01

    The Imagery Exchange (TIE) is a scalable and efficient imagery data management system that powers the WMS web server OnEarth. Designed and developed at the Jet Propulsion Laboratory (JPL), TIE's primary purpose was to power the NASA's Global Imagery Browse Services (GIBS), a system that provides full resolution imagery from a broad set of Earth science disciplines to the public. The SMAP project at JPL had just about all of its requirements met with GIBS but required very project-specific behavior and automation for the Cal-Val phase of the project. Thanks to the extendable design of TIE (already an extension of JPL's Horizon framework) and Amazon's GovCloud services, we were able to meet the needs of the project without any rewrite of the system while significantly expanding the capabilities of an already robust system through well modularized feature additions. In this presentation, we will talk about the efforts made to re-use the already developed data system TIE for SMAP with minimal turn around. Leveraging cloud resources and standard interfaces, we were able to satisfy new project requirements in a very short amount of time.

  18. Elasticity-induced force reversal between active spinning particles in dense passive media

    PubMed Central

    Aragones, J. L.; Steimel, J. P.; Alexander-Katz, A.

    2016-01-01

    The self-organization of active particles is governed by their dynamic effective interactions. Such interactions are controlled by the medium in which such active agents reside. Here we study the interactions between active agents in a dense non-active medium. Our system consists of actuated, spinning, active particles embedded in a dense monolayer of passive, or non-active, particles. We demonstrate that the presence of the passive monolayer alters markedly the properties of the system and results in a reversal of the forces between active spinning particles from repulsive to attractive. The origin of such reversal is due to the coupling between the active stresses and elasticity of the system. This discovery provides a mechanism for the interaction between active agents in complex and structured media, opening up opportunities to tune the interaction range and directionality via the mechanical properties of the medium. PMID:27112961

  19. Elasticity-induced force reversal between active spinning particles in dense passive media.

    PubMed

    Aragones, J L; Steimel, J P; Alexander-Katz, A

    2016-04-26

    The self-organization of active particles is governed by their dynamic effective interactions. Such interactions are controlled by the medium in which such active agents reside. Here we study the interactions between active agents in a dense non-active medium. Our system consists of actuated, spinning, active particles embedded in a dense monolayer of passive, or non-active, particles. We demonstrate that the presence of the passive monolayer alters markedly the properties of the system and results in a reversal of the forces between active spinning particles from repulsive to attractive. The origin of such reversal is due to the coupling between the active stresses and elasticity of the system. This discovery provides a mechanism for the interaction between active agents in complex and structured media, opening up opportunities to tune the interaction range and directionality via the mechanical properties of the medium.

  20. Elasticity-induced force reversal between active spinning particles in dense passive media

    NASA Astrophysics Data System (ADS)

    Aragones, J. L.; Steimel, J. P.; Alexander-Katz, A.

    2016-04-01

    The self-organization of active particles is governed by their dynamic effective interactions. Such interactions are controlled by the medium in which such active agents reside. Here we study the interactions between active agents in a dense non-active medium. Our system consists of actuated, spinning, active particles embedded in a dense monolayer of passive, or non-active, particles. We demonstrate that the presence of the passive monolayer alters markedly the properties of the system and results in a reversal of the forces between active spinning particles from repulsive to attractive. The origin of such reversal is due to the coupling between the active stresses and elasticity of the system. This discovery provides a mechanism for the interaction between active agents in complex and structured media, opening up opportunities to tune the interaction range and directionality via the mechanical properties of the medium.

  1. Active and Passive Spatial Learning in Human Navigation: Acquisition of Graph Knowledge

    ERIC Educational Resources Information Center

    Chrastil, Elizabeth R.; Warren, William H.

    2015-01-01

    It is known that active exploration of a new environment leads to better spatial learning than does passive visual exposure. We ask whether specific components of active learning differentially contribute to particular forms of spatial knowledge--the "exploration-specific learning hypothesis". Previously, we found that idiothetic…

  2. Active versus Passive Proprioceptive Straight-Ahead Pointing in Normal Subjects

    ERIC Educational Resources Information Center

    Chokron, Sylvie; Colliot, Pascale; Atzeni, Thierry; Bartolomeo, Paolo; Ohlmann, Theophile

    2004-01-01

    Eighty blindfolded healthy female subjects participated in an active and a passive straight-ahead pointing task to study the estimation of the subjective sagittal middle in the presence or absence of an active haptic exploration. Subjects were to point straight-ahead with their left or right index finger starting from different right- or…

  3. Active and Passive Spatial Learning in Human Navigation: Acquisition of Survey Knowledge

    ERIC Educational Resources Information Center

    Chrastil, Elizabeth R.; Warren, William H.

    2013-01-01

    It seems intuitively obvious that active exploration of a new environment would lead to better spatial learning than would passive visual exposure. It is unclear, however, which components of active learning contribute to spatial knowledge, and previous literature is decidedly mixed. This experiment tests the contributions of 4 components to…

  4. The cognitive-behavioral system of leadership: cognitive antecedents of active and passive leadership behaviors.

    PubMed

    Dóci, Edina; Stouten, Jeroen; Hofmans, Joeri

    2015-01-01

    In the present paper, we propose a cognitive-behavioral understanding of active and passive leadership. Building on core evaluations theory, we offer a model that explains the emergence of leaders' active and passive behaviors, thereby predicting stable, inter-individual, as well as variable, intra-individual differences in both types of leadership behavior. We explain leaders' stable behavioral tendencies by their fundamental beliefs about themselves, others, and the world (core evaluations), while their variable, momentary behaviors are explained by the leaders' momentary appraisals of themselves, others, and the world (specific evaluations). By introducing interactions between the situation the leader enters, the leader's beliefs, appraisals, and behavior, we propose a comprehensive system of cognitive mechanisms that underlie active and passive leadership behavior. PMID:26441721

  5. The cognitive-behavioral system of leadership: cognitive antecedents of active and passive leadership behaviors

    PubMed Central

    Dóci, Edina; Stouten, Jeroen; Hofmans, Joeri

    2015-01-01

    In the present paper, we propose a cognitive-behavioral understanding of active and passive leadership. Building on core evaluations theory, we offer a model that explains the emergence of leaders’ active and passive behaviors, thereby predicting stable, inter-individual, as well as variable, intra-individual differences in both types of leadership behavior. We explain leaders’ stable behavioral tendencies by their fundamental beliefs about themselves, others, and the world (core evaluations), while their variable, momentary behaviors are explained by the leaders’ momentary appraisals of themselves, others, and the world (specific evaluations). By introducing interactions between the situation the leader enters, the leader’s beliefs, appraisals, and behavior, we propose a comprehensive system of cognitive mechanisms that underlie active and passive leadership behavior. PMID:26441721

  6. Variability in measurement of swimming forces: a meta-analysis of passive and active drag.

    PubMed

    Havriluk, Rod

    2007-03-01

    An analysis was conducted to identify sources of true and error variance in measuring swimming drag force to draw valid conclusions about performance factor effects. Passive drag studies were grouped according to methodological differences: tow line in pool, tow line in flume, and carriage in tow tank. Active drag studies were grouped according to the theoretical basis: added and/or subtracted drag (AAS), added drag with equal power assumption (AAE), and no added drag (ANA). Data from 36 studies were examined using frequency distributions and meta-analytic procedures. It was concluded that two active methods (AAE and ANA) had sources of systematic error and that one active method (AAS) measured an effect that was different from that measured by passive methods. Consistency in drag coefficient (Cd) values across all three passive methods made it possible to determine the effects of performance factors.

  7. Effect of active vs. passive recovery on repeat suicide run time.

    PubMed

    Graham, James E; Douglas Boatwright, J; Hunskor, Martha J; Howell, Dan C

    2003-05-01

    This study was conducted to evaluate the difference between active and passive recovery methods during successive suicide runs by Division I women's collegiate basketball athletes (n = 14). Testing consisted of sprinting suicides on the basketball court using both traditional (short) and reverse-sequence (long) protocols. Two 90-second recovery methods were used, passive (standing still) and active (slow self-paced jogging). Although successive run time was reduced by a mean of 0.55 seconds after passive recovery relative to active, it did not reach significance (p = 0.09). Likewise, the difference between long and short line versions was nonsignificant (p = 0.41). Therefore, neither line sequence nor 90-second recovery technique appears to influence subsequent run time when performing 2 maximal-effort suicides. PMID:12741874

  8. Anisotropic Elastography for Local Passive Properties and Active Contractility of Myocardium from Dynamic Heart Imaging Sequence

    PubMed Central

    Wang, Ge; Sun, L. Z.

    2006-01-01

    Major heart diseases such as ischemia and hypertrophic myocardiopathy are accompanied with significant changes in the passive mechanical properties and active contractility of myocardium. Identification of these changes helps diagnose heart diseases, monitor therapy, and design surgery. A dynamic cardiac elastography (DCE) framework is developed to assess the anisotropic viscoelastic passive properties and active contractility of myocardial tissues, based on the chamber pressure and dynamic displacement measured with cardiac imaging techniques. A dynamic adjoint method is derived to enhance the numerical efficiency and stability of DCE. Model-based simulations are conducted using a numerical left ventricle (LV) phantom with an ischemic region. The passive material parameters of normal and ischemic tissues are identified during LV rapid/reduced filling and artery contraction, and those of active contractility are quantified during isovolumetric contraction and rapid/reduced ejection. It is found that quasistatic simplification in the previous cardiac elastography studies may yield inaccurate material parameters. PMID:23165032

  9. Effect of active vs. passive recovery on repeat suicide run time.

    PubMed

    Graham, James E; Douglas Boatwright, J; Hunskor, Martha J; Howell, Dan C

    2003-05-01

    This study was conducted to evaluate the difference between active and passive recovery methods during successive suicide runs by Division I women's collegiate basketball athletes (n = 14). Testing consisted of sprinting suicides on the basketball court using both traditional (short) and reverse-sequence (long) protocols. Two 90-second recovery methods were used, passive (standing still) and active (slow self-paced jogging). Although successive run time was reduced by a mean of 0.55 seconds after passive recovery relative to active, it did not reach significance (p = 0.09). Likewise, the difference between long and short line versions was nonsignificant (p = 0.41). Therefore, neither line sequence nor 90-second recovery technique appears to influence subsequent run time when performing 2 maximal-effort suicides.

  10. Neural Substrates Underlying the Passive Observation and Active Control of Translational Egomotion

    PubMed Central

    Chen, Ching-fu; Sereno, Martin I.

    2015-01-01

    Moving or static obstacles often get in the way while walking in daily life. Avoiding obstacles involves both perceptual processing of motion information and controlling appropriate defensive movements. Several higher-level motion areas, including the ventral intraparietal area (VIP), medial superior temporal area, parieto-insular vestibular cortex (PIVC), areas V6 and V6A, and cingulate sulcus visual area, have been identified in humans by passive viewing of optic flow patterns that simulate egomotion and object motion. However, the roles of these areas in the active control of egomotion in the real world remain unclear. Here, we used functional magnetic resonance imaging (fMRI) to map the neural substrates underlying the passive observation and active control of translational egomotion in humans. A wide-field virtual reality environment simulated a daily scenario where doors randomly swing outward while walking in a hallway. The stimuli of door-dodging events were essentially the same in two event-related fMRI experiments, which compared passive and active dodges in response to swinging doors. Passive dodges were controlled by a computer program, while active dodges were controlled by the subject. Passive dodges activated several higher-level areas distributed across three dorsal motion streams in the temporal, parietal, and cingulate cortex. Active dodges most strongly activated the temporal–vestibular stream, with peak activation located in the right PIVC. Other higher-level motion areas including VIP showed weaker to no activation in active dodges. These results suggest that PIVC plays an active role in sensing and guiding translational egomotion that moves an observer aside from impending obstacles. PMID:25762672

  11. 3D shoulder kinematics for static vs dynamic and passive vs active testing conditions.

    PubMed

    Robert-Lachaine, Xavier; Allard, Paul; Godbout, Véronique; Begon, Mickael

    2015-09-18

    Shoulder motion analysis provides clinicians with references of normal joint rotations. Shoulder joints orientations assessment is often based on series of static positions, while clinicians perform either passive or active tests and exercises mostly in dynamic. These conditions of motion could modify joint coordination and lead to discrepancies with the established references. Hence, the objective was to evaluate the influence of static vs dynamic and passive vs active testing conditions on shoulder joints orientations. Twenty asymptomatic subjects setup with 45 markers on the upper limb and trunk were tracked by an optoelectronic system. Static positions (30°, 60°, 90° and 120° of thoracohumeral elevation) and dynamic motion both in active condition and passively mobilised by an examiner were executed. Three-dimensional sternoclavicular, acromioclavicular, scapulothoracic and glenohumeral joint angles (12 in total) representing the distal segment orientation relative to the proximal segment orientation were estimated using a shoulder kinematical chain model. Separate four-way repeated measures ANOVA were applied on the 12 joint angles with factors of static vs dynamic, passive vs active, thoracohumeral elevation angle (30°, 60°, 90° and 120°) and plane of elevation (frontal and sagittal). Scapulothoracic lateral rotation progressed more during arm elevation in static than in dynamic gaining 4.2° more, and also in passive than in active by 6.6°. Glenohumeral elevation increased more during arm elevation in active than in passive by 4.4°. Shoulder joints orientations are affected by the testing conditions, which should be taken into consideration for data acquisition, inter-study comparison or clinical applications.

  12. Passive and active exercises are similarly effective in elderly nursing home residents

    PubMed Central

    Takahashi, Takeshi; Takeshima, Nobuo; Rogers, Nicole L.; Rogers, Michael E.; Islam, Mohammod Monirul

    2015-01-01

    [Purpose] The aim of this study was to compare the efficacy of passive motion exercise and active motion exercise on functional fitness in elderly nursing home residents. [Subjects and Methods] Twenty-three (female 22 and male 1) nursing home residents (84.8±4.3 yr) volunteered for this study. They were divided into a passive motion exercise group (n=12) and an active motion exercise group (n=11) and performed 30-min sessions of training twice a week for 12 weeks. Functional fitness (Arm Curl, Chair Stand, Up & Go, Sit & Reach, Back Scratch, functional Reach, and 12-min Walk tests) was evaluated before and after the intervention. [Results] No significant baseline difference was noted between the groups in measured variables. Following the 12 week intervention, no significant interaction (group × time) was noted in functional fitness variables between the groups, except for the functional reach scores (active motion exercise 40%, passive motion exercise 9%). Significant improvement over time was noted in passive motion exercise group in Arm Curl (19%), Chair Stand (15%), Up & Go (6%), and 12-min Walk (12%) scores; and in the active motion exercise group in Arm Curl (14%), Chair Stand (19%), Up & Go (11%), functional Reach (40%) and 12-min Walk (13%) scores. The adherence rates in the passive and active motion exercise groups were 95.8% and 93.1% respectively. [Conclusion] Passive motion exercise and active motion exercise were found to be similarly effective for improving the functional fitness of elderly nursing home residents. PMID:26504320

  13. Plant chlorophyll fluorescence: active and passive measurements at canopy and leaf scales with different nitrogen treatments

    PubMed Central

    Cendrero-Mateo, M. Pilar; Moran, M. Susan; Papuga, Shirley A.; Thorp, K.R.; Alonso, L.; Moreno, J.; Ponce-Campos, G.; Rascher, U.; Wang, G.

    2016-01-01

    Most studies assessing chlorophyll fluorescence (ChlF) have examined leaf responses to environmental stress conditions using active techniques. Alternatively, passive techniques are able to measure ChlF at both leaf and canopy scales. However, the measurement principles of both techniques are different, and only a few datasets concerning the relationships between them are reported in the literature. In this study, we investigated the potential for interchanging ChlF measurements using active techniques with passive measurements at different temporal and spatial scales. The ultimate objective was to determine the limits within which active and passive techniques are comparable. The results presented in this study showed that active and passive measurements were highly correlated over the growing season across nitrogen treatments at both canopy and leaf-average scale. At the single-leaf scale, the seasonal relation between techniques was weaker, but still significant. The variability within single-leaf measurements was largely related to leaf heterogeneity associated with variations in CO2 assimilation and stomatal conductance, and less so to variations in leaf chlorophyll content, leaf size or measurement inputs (e.g. light reflected and emitted by the leaf and illumination conditions and leaf spectrum). This uncertainty was exacerbated when single-leaf analysis was limited to a particular day rather than the entire season. We concluded that daily measurements of active and passive ChlF at the single-leaf scale are not comparable. However, canopy and leaf-average active measurements can be used to better understand the daily and seasonal behaviour of passive ChlF measurements. In turn, this can be used to better estimate plant photosynthetic capacity and therefore to provide improved information for crop management. PMID:26482242

  14. Plant chlorophyll fluorescence: active and passive measurements at canopy and leaf scales with different nitrogen treatments.

    PubMed

    Cendrero-Mateo, M Pilar; Moran, M Susan; Papuga, Shirley A; Thorp, K R; Alonso, L; Moreno, J; Ponce-Campos, G; Rascher, U; Wang, G

    2016-01-01

    Most studies assessing chlorophyll fluorescence (ChlF) have examined leaf responses to environmental stress conditions using active techniques. Alternatively, passive techniques are able to measure ChlF at both leaf and canopy scales. However, the measurement principles of both techniques are different, and only a few datasets concerning the relationships between them are reported in the literature. In this study, we investigated the potential for interchanging ChlF measurements using active techniques with passive measurements at different temporal and spatial scales. The ultimate objective was to determine the limits within which active and passive techniques are comparable. The results presented in this study showed that active and passive measurements were highly correlated over the growing season across nitrogen treatments at both canopy and leaf-average scale. At the single-leaf scale, the seasonal relation between techniques was weaker, but still significant. The variability within single-leaf measurements was largely related to leaf heterogeneity associated with variations in CO2 assimilation and stomatal conductance, and less so to variations in leaf chlorophyll content, leaf size or measurement inputs (e.g. light reflected and emitted by the leaf and illumination conditions and leaf spectrum). This uncertainty was exacerbated when single-leaf analysis was limited to a particular day rather than the entire season. We concluded that daily measurements of active and passive ChlF at the single-leaf scale are not comparable. However, canopy and leaf-average active measurements can be used to better understand the daily and seasonal behaviour of passive ChlF measurements. In turn, this can be used to better estimate plant photosynthetic capacity and therefore to provide improved information for crop management.

  15. Vaginal cone use in passive and active phases in patients with stress urinary incontinence

    PubMed Central

    Haddad, Jorge Milhem; Ribeiro, Ricardo Muniz; Bernardo, Wanderley Marques; Abrão, Maurício Simões; Baracat, Edmund Chada

    2011-01-01

    OBJECTIVE: To evaluate vaginal cone therapy in two phases, passive and active, in women with stress urinary incontinence. METHODS: A prospective study was conducted at the Department of Obstetrics and Gynecology, São Paulo University, Brazil. Twenty-four women with a clinical and urodynamic diagnosis of stress urinary incontinence were treated with vaginal cones in a passive phase (without voluntary contractions of the pelvic floor) and an active phase (with voluntary contractions), each of which lasted three months. Clinical complaints, a functional evaluation of the pelvic floor, a pad test, and bladder neck mobility were analyzed before and after each phase. RESULTS: Twenty-one patients completed the treatment. The reduction in absolute risk with the pad test was 0.38 (p<0.034) at the end of the passive phase and 0.67 (p<0.0001) at the end of the active phase. The reduction in absolute risk with the pelvic floor evaluation was 0.62 (p<0.0001) at the end of the passive phase and 0.77 (p<0.0001) at the end of the active phase. The reduction in absolute risk of bladder neck mobility was 0.38 (p<0.0089) at the end of the passive phase and 0.52 (p<0.0005) at the end of the active phase. Complete reversal of symptomatology was observed in 12 (57.1%) patients, and satisfaction was expressed by 19 (90.4%). CONCLUSION: Using vaginal cones in the passive phase, as other researchers did, was effective. Inclusion of the active phase led to additional improvement in all of the study parameters evaluated in women with stress urinary incontinence. Randomized studies are needed, however, to confirm these results. PMID:21789381

  16. 26 CFR 1.469-2 - Passive activity loss.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... the value of the building. Accordingly, an amount equal to A's net rental activity income from the... amount of A's gross rental activity income from the building for 1997 equal to A's net rental activity...)(2)(iii): Example 1. A acquires a building on January 1, 1993, and uses the building in a trade...

  17. 26 CFR 1.469-2 - Passive activity loss.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... the value of the building. Accordingly, an amount equal to A's net rental activity income from the... amount of A's gross rental activity income from the building for 1997 equal to A's net rental activity...)(2)(iii): Example 1. A acquires a building on January 1, 1993, and uses the building in a trade...

  18. The surface geometry of inherited joint and fracture trace patterns resulting from active and passive deformation

    NASA Technical Reports Server (NTRS)

    Podwysocki, M. H.; Gold, D. P.

    1974-01-01

    Hypothetical models are considered for detecting subsurface structure from the fracture or joint pattern, which may be influenced by the structure and propagated to the surface. Various patterns of an initially orthogonal fracture grid are modeled according to active and passive deformation mechanisms. In the active periclinal structure with a vertical axis, fracture frequency increased both over the dome and basin, and remained constant with decreasing depth to the structure. For passive periclinal features such as a reef or sand body, fracture frequency is determined by the arc of curvature and showed a reduction over the reefmound and increased over the basin.

  19. Passive and active plasma deceleration for the compact disposal of electron beams

    SciTech Connect

    Bonatto, A.; Schroeder, C. B.; Vay, J.-L.; Geddes, C. G. R.; Benedetti, C.; Esarey, E.; Leemans, W. P.

    2015-08-15

    Plasma-based decelerating schemes are investigated as compact alternatives for the disposal of high-energy beams (beam dumps). Analytical solutions for the energy loss of electron beams propagating in passive and active (laser-driven) schemes are derived. These solutions, along with numerical modeling, are used to investigate the evolution of the electron distribution, including energy chirp and total beam energy. In the active beam dump scheme, a laser-driver allows a more homogeneous beam energy extraction and drastically reduces the energy chirp observed in the passive scheme. These concepts could benefit applications requiring overall compactness, such as transportable light sources, or facilities operating at high beam power.

  20. Combined passive and active shimming for in vivo MR spectroscopy at high magnetic fields

    NASA Astrophysics Data System (ADS)

    Juchem, Christoph; Muller-Bierl, Bernd; Schick, Fritz; Logothetis, Nikos K.; Pfeuffer, Josef

    2006-12-01

    The use of high magnetic fields increases the sensitivity and spectral dispersion in magnetic resonance spectroscopy (MRS) of brain metabolites. Practical limitations arise, however, from susceptibility-induced field distortions, which are increased at higher magnetic field strengths. Solutions to this problem include optimized shimming, provided that active, i.e., electronic, shimming can operate over a sufficient range. To meet our shim requirements, which were an order of magnitude greater than the active shim capacity of our 7 T MR system, we developed a combined passive and active shim approach. Simple geometries of ferromagnetic shim elements were derived and numerically optimized to generate a complete set of second-order spherical harmonic shim functions in a modular manner. The major goals of the shim design were maximization of shim field accuracy and ease of practical implementation. The theoretically optimized ferro-shim geometries were mounted on a cylindrical surface and placed inside the magnet bore, surrounding the subject's head and the RF coil. Passive shimming generated very strong shim fields and eliminated the worst of the field distortions, after which the field was further optimized by flexible and highly accurate active shimming. Here, the passive-shimming procedure was first evaluated theoretically, then applied in phantom studies and subsequently validated for in vivo1H MRS in the macaque visual cortex. No artifacts due to the passive shim setup were observed; adjustments were reproducible between sessions. The modularity and the reduction to two pieces per shim term in this study is an important simplification that makes the method applicable also for passive shimming within single sessions. The feasibility of very strong, flexible and high-quality shimming via a combined approach of passive and active shimming is of great practical relevance for MR imaging and spectroscopy at high field strengths where shim power is limited or where

  1. Active and passive cigarette smoking and breast cancer risk: results from the EPIC cohort.

    PubMed

    Dossus, Laure; Boutron-Ruault, Marie-Christine; Kaaks, Rudolf; Gram, Inger T; Vilier, Alice; Fervers, Béatrice; Manjer, Jonas; Tjonneland, Anne; Olsen, Anja; Overvad, Kim; Chang-Claude, Jenny; Boeing, Heiner; Steffen, Annika; Trichopoulou, Antonia; Lagiou, Pagona; Sarantopoulou, Maria; Palli, Domenico; Berrino, Franco; Tumino, Rosario; Vineis, Paolo; Mattiello, Amalia; Bueno-de-Mesquita, H Bas; van Duijnhoven, Franzel J B; Bakker, Marieke F; Peeters, Petra Hm; Weiderpass, Elisabete; Bjerkaas, Eivind; Braaten, Tonje; Menéndez, Virginia; Agudo, Antonio; Sanchez, Maria-Jose; Amiano, Pilar; Tormo, Maria-Jose; Barricarte, Aurelio; Butt, Salma; Khaw, Kay-Tee; Wareham, Nicholas; Key, Tim J; Travis, Ruth C; Rinaldi, Sabina; McCormack, Valerie; Romieu, Isabelle; Cox, David G; Norat, Teresa; Riboli, Elio; Clavel-Chapelon, Françoise

    2014-04-15

    Recent cohort studies suggest that increased breast cancer risks were associated with longer smoking duration, higher pack-years and a dose-response relationship with increasing pack-years of smoking between menarche and first full-term pregnancy (FFTP). Studies with comprehensive quantitative life-time measures of passive smoking suggest an association between passive smoking dose and breast cancer risk. We conducted a study within the European Prospective Investigation into Cancer and Nutrition to examine the association between passive and active smoking and risk of invasive breast cancer and possible effect modification by known breast cancer risk factors. Among the 322,988 women eligible for the study, 9,822 developed breast cancer (183,608 women with passive smoking information including 6,264 cases). When compared to women who never smoked and were not being exposed to passive smoking at home or work at the time of study registration, current, former and currently exposed passive smokers were at increased risk of breast cancer (hazard ratios (HR) [95% confidence interval (CI)] 1.16 [1.05-1.28], 1.14 [1.04-1.25] and 1.10 [1.01-1.20], respectively). Analyses exploring associations in different periods of life showed the most important increase in risk with pack-years from menarche to FFTP (1.73 [1.29-2.32] for every increase of 20 pack-years) while pack-years smoked after menopause were associated with a significant decrease in breast cancer risk (HR = 0.53, 95% CI: 0.34-0.82 for every increase of 20 pack-years). Our results provide an important replication, in the largest cohort to date, that smoking (passively or actively) increases breast cancer risk and that smoking between menarche and FFTP is particularly deleterious.

  2. Active and passive cigarette smoking and breast cancer risk: results from the EPIC cohort.

    PubMed

    Dossus, Laure; Boutron-Ruault, Marie-Christine; Kaaks, Rudolf; Gram, Inger T; Vilier, Alice; Fervers, Béatrice; Manjer, Jonas; Tjonneland, Anne; Olsen, Anja; Overvad, Kim; Chang-Claude, Jenny; Boeing, Heiner; Steffen, Annika; Trichopoulou, Antonia; Lagiou, Pagona; Sarantopoulou, Maria; Palli, Domenico; Berrino, Franco; Tumino, Rosario; Vineis, Paolo; Mattiello, Amalia; Bueno-de-Mesquita, H Bas; van Duijnhoven, Franzel J B; Bakker, Marieke F; Peeters, Petra Hm; Weiderpass, Elisabete; Bjerkaas, Eivind; Braaten, Tonje; Menéndez, Virginia; Agudo, Antonio; Sanchez, Maria-Jose; Amiano, Pilar; Tormo, Maria-Jose; Barricarte, Aurelio; Butt, Salma; Khaw, Kay-Tee; Wareham, Nicholas; Key, Tim J; Travis, Ruth C; Rinaldi, Sabina; McCormack, Valerie; Romieu, Isabelle; Cox, David G; Norat, Teresa; Riboli, Elio; Clavel-Chapelon, Françoise

    2014-04-15

    Recent cohort studies suggest that increased breast cancer risks were associated with longer smoking duration, higher pack-years and a dose-response relationship with increasing pack-years of smoking between menarche and first full-term pregnancy (FFTP). Studies with comprehensive quantitative life-time measures of passive smoking suggest an association between passive smoking dose and breast cancer risk. We conducted a study within the European Prospective Investigation into Cancer and Nutrition to examine the association between passive and active smoking and risk of invasive breast cancer and possible effect modification by known breast cancer risk factors. Among the 322,988 women eligible for the study, 9,822 developed breast cancer (183,608 women with passive smoking information including 6,264 cases). When compared to women who never smoked and were not being exposed to passive smoking at home or work at the time of study registration, current, former and currently exposed passive smokers were at increased risk of breast cancer (hazard ratios (HR) [95% confidence interval (CI)] 1.16 [1.05-1.28], 1.14 [1.04-1.25] and 1.10 [1.01-1.20], respectively). Analyses exploring associations in different periods of life showed the most important increase in risk with pack-years from menarche to FFTP (1.73 [1.29-2.32] for every increase of 20 pack-years) while pack-years smoked after menopause were associated with a significant decrease in breast cancer risk (HR = 0.53, 95% CI: 0.34-0.82 for every increase of 20 pack-years). Our results provide an important replication, in the largest cohort to date, that smoking (passively or actively) increases breast cancer risk and that smoking between menarche and FFTP is particularly deleterious. PMID:24590452

  3. Active/passive scanning. [airborne multispectral laser scanners for agricultural and water resources applications

    NASA Technical Reports Server (NTRS)

    Woodfill, J. R.; Thomson, F. J.

    1979-01-01

    The paper deals with the design, construction, and applications of an active/passive multispectral scanner combining lasers with conventional passive remote sensors. An application investigation was first undertaken to identify remote sensing applications where active/passive scanners (APS) would provide improvement over current means. Calibration techniques and instrument sensitivity are evaluated to provide predictions of the APS's capability to meet user needs. A preliminary instrument design was developed from the initial conceptual scheme. A design review settled the issues of worthwhile applications, calibration approach, hardware design, and laser complement. Next, a detailed mechanical design was drafted and construction of the APS commenced. The completed APS was tested and calibrated in the laboratory, then installed in a C-47 aircraft and ground tested. Several flight tests completed the test program.

  4. Heat transfer measurements in ONERA supersonic and hypersonic wind tunnels using passive and active infrared thermography

    NASA Astrophysics Data System (ADS)

    Balageas, D.; Boscher, D.; Deom, A.; Gardette, G.

    Over the past few years, a major intellectual and technical investment has been made at ONERA to use data acquisition systems and data reduction procedures using an infrared camera as a detector under routine wind tunnel conditions. This allows a really quantitative mapping of heat transfer rate distributions on models in supersonic and hypersonic flows. Sufficient experience has now been acquired to allow us to give an overview of: (1) the systems and data reduction procedures developed for both passive and active methods; (2) typical results obtained on various configurations such as supersonic axisymmetrical flow around an ogival body (passive and active thermography), heat flux modulation in the reattachment zone of a flap in hypersonic regime, transitional heating on very slightly blunted spheroconical bodies in hypersonic flows, and materials testing in high-enthalpy hypersonic flow (passive thermography).

  5. A Comparison of Active and Passive Methods for Control of Hypersonic Boundary Layers on Airbreathing Configurations

    NASA Technical Reports Server (NTRS)

    Berry, Scott A.; Nowak, Robert J.

    2003-01-01

    Active and passive methods for control of hypersonic boundary layers have been experimentally examined in NASA Langley Research Center wind tunnels on a Hyper-X model. Several configurations for forcing transition using passive discrete roughness elements and active mass addition, or blowing, methods were compared in two hypersonic facilities, the 20-Inch Mach 6 Air and the 31-Inch Mach 10 Air tunnels. Heat transfer distributions, obtained via phosphor thermography, shock system details, and surface streamline patterns were measured on a 0.333-scale model of the Hyper-X forebody. The comparisons between the active and passive methods for boundary layer control were conducted at test conditions that nearly match the nominal Mach 7 flight trajectory of an angle-of-attack of 2-deg and length Reynolds number of 5.6 million. For the passive roughness examination, the primary parametric variation was a range of trip heights within the calculated boundary layer thickness for several trip concepts. The prior passive roughness study resulted in a swept ramp configuration being selected for the Mach 7 flight vehicle that was scaled to be roughly 0.6 of the calculated boundary layer thickness. For the active jet blowing study, the blowing manifold pressure was systematically varied for each configuration, while monitoring the mass flow, to determine the jet penetration height with schlieren and transition movement with the phosphor system for comparison to the passive results. All the blowing concepts tested were adequate for providing transition onset near the trip location with manifold stagnation pressures on the order of 40 times the model static pressure or higher.

  6. Active and passive computed tomography algorithm with a constrained conjugate gradient solution

    SciTech Connect

    Goodman, D.; Jackson, J. A.; Martz, H. E.; Roberson, G. P.

    1998-10-01

    An active and passive computed tomographic technique (A&PCT) has been developed at the Lawrence Livermore National Laboratory (LLNL). The technique uses an external radioactive source and active tomography to map the attenuation within a waste drum as a function of mono-energetic gamma-ray energy. Passive tomography is used to localize and identify specific radioactive waste within the same container. The passive data is corrected for attenuation using the active data and this yields a quantitative assay of drum activity. A&PCT involves the development of a detailed system model that combines the data from the active scans with the geometry of the imaging system. Using the system model, iterative optimization techniques are used to reconstruct the image from the passive data. Requirements for high throughput yield measured emission levels in waste barrels that are too low to apply optimization techniques involving the usual Gaussian statistics. In this situation a Poisson distribution, typically used for cases with low counting statistics, is used to create an effective maximum likelihood estimation function. An optimization algorithm, Constrained Conjugate Gradient (CCG), is used to determine a solution for A&PCT quantitative assay. CCG, which was developed at LLNL, has proven to be an efficient and effective optimization method to solve limited-data problems. A detailed explanation of the algorithms used in developing the model and optimization codes is given.

  7. Seismic response of torsionally coupled building with passive and semi-active stiffness dampers

    NASA Astrophysics Data System (ADS)

    Mevada, Snehal V.; Jangid, R. S.

    2015-03-01

    The seismic response of single-storey, one-way asymmetric building with passive and semi-active variable stiffness dampers is investigated. The governing equations of motion are derived based on the mathematical model of asymmetric building. The seismic response of the system is obtained by numerically solving the equations of motion using state-space method under different system parameters. The switching and resetting control laws are considered for the semi-active devices. The important parameters considered are eccentricity ratio of superstructure, uncoupled lateral time period and ratio of uncoupled torsional to lateral frequency. The effects of these parameters are investigated on peak lateral, torsional and edge displacements and accelerations as well as on damper control forces. The comparative performance is investigated for asymmetric building installed with passive stiffness and semi-active stiffness dampers. It is shown that the semi-active stiffness dampers reduce the earthquake-induced displacements and accelerations significantly as compared to passive stiffness dampers. Also, the effects of torsional coupling on effectiveness of passive dampers in reducing displacements and accelerations are found to be more significant to the variation of eccentricity as compared to semi-active stiffness dampers.

  8. Re-active Passive (RAP) Devices for Control of Noise Transmission through a Panel

    NASA Technical Reports Server (NTRS)

    Carneal, James P.; Giovanardi, Marco; Fuller, Chris R.; Palumbo, Daniel L.

    2008-01-01

    Re-Active Passive (RAP) devices have been developed to control low frequency (<1000 Hz) noise transmission through a panel. These devices use a combination of active, re-active, and passive technologies packaged into a single unit to control a broad frequency range utilizing the strength of each technology over its best suited frequency range. The RAP device uses passive constrained layer damping to cover the relatively high frequency range (>200 Hz), reactive distributed vibration absorber) to cover the medium frequency range (75 to 250 Hz), and active control for controlling low frequencies (<200 Hz). The device was applied to control noise transmission through a panel mounted in a transmission loss test facility. Experimental results are presented for the bare panel, and combinations of passive treatment, reactive treatment, and active control. Results indicate that three RAP devices were able to increase the overall broadband (15-1000 Hz) transmission loss by 9.4 dB. These three devices added a total of 285 grams to the panel mass of 6.0 kg, or approximately 5%, not including control electronics.

  9. Passive and Active Protective Clothing against High-Power Laser Radiation

    NASA Astrophysics Data System (ADS)

    Hennigs, C.; Hustedt, M.; Kaierle, S.; Wenzel, D.; Markstein, S.; Hutter, A.

    The main objective of the work described in this paper was the development of passive and active protective clothing for the protection of the human skin against accidental laser irradiation and of active protective curtains. Here, the passive systems consist of functional multi-layer textiles, providing a high level of passive laser resistance. In addition, the active functional multi-layer textiles incorporate sensors that detect laser exposure and are, by means of a safety control, able to deactivate the laser beam automatically.Due to the lack of regulations for testing and qualifying textiles to be used as laser PPE, test methods were defined and validated. Additionally, corresponding testing set-ups were developed.Finally, the gap with respect to standardization was bridged by the definition of a test procedure and the requirements with respect to laser PPE.The developments were demonstrated by a set of tailored functional passive and active laser-protective clothing prototypes (gloves, jackets, aprons, trousers) and active curtains as well as by a prototype testing rig, providing the possibility to perform the specified low-power and high-power textile test procedure.

  10. Passive and active pulse stacking scheme for pulse shaping

    DOEpatents

    Harney, Robert C.; Schipper, John F.

    1977-01-01

    Apparatus and method for producing a sequence of radiation pulses with a pulse envelope of time variation which is controllable by an external electromagnetic signal applied to an active medium or by a sectored reflector, through which the radiation passes.

  11. Detection of septic transfusion reactions to platelet transfusions by active and passive surveillance.

    PubMed

    Hong, Hong; Xiao, Wenbin; Lazarus, Hillard M; Good, Caryn E; Maitta, Robert W; Jacobs, Michael R

    2016-01-28

    Septic transfusion reactions (STRs) resulting from transfusion of bacterially contaminated platelets are a major hazard of platelet transfusion despite recent interventions. Active and passive surveillance for bacterially contaminated platelets was performed over 7 years (2007-2013) by culture of platelet aliquots at time of transfusion and review of reported transfusion reactions. All platelet units had been cultured 24 hours after collection and released as negative. Five sets of STR criteria were evaluated, including recent AABB criteria; sensitivity and specificity of these criteria, as well as detection by active and passive surveillance, were determined. Twenty of 51,440 platelet units transfused (0.004%; 389 per million) were bacterially contaminated by active surveillance and resulted in 5 STRs occurring 9 to 24 hours posttransfusion; none of these STRs had been reported by passive surveillance. STR occurred only in neutropenic patients transfused with high bacterial loads. A total of 284 transfusion reactions (0.55%) were reported by passive surveillance. None of these patients had received contaminated platelets. However, 6 to 93 (2.1%-32.7%) of these 284 reactions met 1 or more STR criteria, and sensitivity of STR criteria varied from 5.1% to 45.5%. These results document the continued occurrence of bacterial contamination of platelets resulting in STR in neutropenic patients, failure of passive surveillance to detect STR, and lack of specificity of STR criteria. These findings highlight the limitations of reported national STR data based on passive surveillance and the need to implement further measures to address this problem such as secondary testing or use of pathogen reduction technologies.

  12. A passive-active neutron device for assaying remote-handled transuranic waste

    SciTech Connect

    Estep, R.J.; Coop, K.L.; Deane, T.M.; Lujan, J.E.

    1989-01-01

    A combined passive-active neutron assay device was constructed for assaying remote-handled transuranic waste. A study of matrix and source position effects in active assays showed that a knowledge of the source position alone is not sufficient to correct for position-related errors in highly moderating or absorbing matrices. An alternate function for the active assay of solid fuel pellets was derived, although the efficacy of this approach remains to be established. 4 refs., 7 figs., 1 tab.

  13. Passive vs. Active Control of Rhythmic Ball Bouncing: The Role of Visual Information

    ERIC Educational Resources Information Center

    Siegler, Isabelle A.; Bardy, Benoit G.; Warren, William H.

    2010-01-01

    The simple task of bouncing a ball on a racket offers a model system for studying how human actors exploit the physics and information of the environment to control their behavior. Previous work shows that people take advantage of a passively stable solution for ball bouncing but can also use perceptual information to actively stabilize bouncing.…

  14. Utilization of active microwave roughness measurements to improve passive microwave soil moisture estimates over bare soils

    NASA Technical Reports Server (NTRS)

    Theis, S. W.; Blanchard, B. J.; Blanchard, A. J.

    1984-01-01

    Multisensor aircraft data were used to establish the potential of the active microwave sensor response to be used to compensate for roughness in the passive microwave sensor's response to soil moisture. Only bare fields were used. It is found that the L-band radiometer's capability to estimate soil moisture significantly improves when surface roughness is accounted for with the scatterometers.

  15. Utilization of active microwave roughness measurements to improve passive microwave soil moisture estimates over bare soils

    NASA Technical Reports Server (NTRS)

    Theis, S. W.; Blanchard, A. J.; Blanchard, B. J.

    1986-01-01

    Multisensor aircraft data were used to establish the potential of the active microwave sensor response to be used to compensate for roughness in the passive microwave sensor's response to soil moisture. Only bare fields were used. It is found that the L-band radiometer's capability to estimate soil moisture significantly improves when surface roughness is accounted for with the scatterometers.

  16. 26 CFR 1.469-2T - Passive activity loss (temporary).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... year exceed the passive activity gross income for the taxable year. (2) Cross references. See paragraph... or business of performing such services or selling such property, but only if credit is customarily... such entity. (4) Cross reference. For special rules applicable to certain gross income from a trade...

  17. Temperatures Achieved in Human and Canine Neocortex During Intraoperative Passive or Active Focal Cooling

    PubMed Central

    Han, Rowland H.; Yarbrough, Chester K.; Patterson, Edward E.; Yang, Xiao-Feng; Miller, John W.; Rothman, Steven M.; D'Ambrosio, Raimondo

    2015-01-01

    Focal cortical cooling inhibits seizures and prevents acquired epileptogenesis in rodents. To investigate the potential clinical utility of this treatment modality, we examined the thermal characteristics of canine and human brain undergoing active and passive surface cooling in intraoperative settings. Four patients with intractable epilepsy were treated in a standard manner. Before the resection of a neocortical epileptogenic focus, multiple intraoperative studies of active (custom-made cooled irrigation-perfused grid) and passive (stainless steel probe) cooling were performed. We also actively cooled the neocortices of two dogs with perfused grids implanted for 2 hours. Focal surface cooling of the human brain causes predictable depth-dependent cooling of the underlying brain tissue. Cooling of 0.6–2°C was achieved both actively and passively to a depth of 10–15 mm from the cortical surface. The perfused grid permitted comparable and persistent cooling of canine neocortex when the craniotomy was closed. Thus, the human cortex can easily be cooled with the use of simple devices such as a cooling grid or a small passive probe. These techniques provide pilot data for the design of a permanently implantable device to control intractable epilepsy. PMID:25902001

  18. Geochemical discrimination of siliciclastic sediments from active and passive margin settings

    NASA Astrophysics Data System (ADS)

    Verma, Surendra P.; Armstrong-Altrin, John S.

    2016-03-01

    Discrimination of active and passive margins is important from both academic and economic aspects. This can only be successfully achieved, however, if there are major compositional differences among sediments derived from different continental margins. A worldwide database of active and passive margin settings was established from published major and trace element geochemical data of Neogene to Quaternary siliciclastic sediments. These data were used to evaluate the performance of existing discrimination diagrams, which were shown to work unsatisfactorily with success values of mostly between 0% and 30%. Because these diagrams were not based on a statistically coherent methodology, we proposed two new discriminant functions from linear discriminant analysis of multinormally distributed isometric log-transformed ratios of major and combined major and trace elements. These new diagrams showed very high percent success values of about 87%-97% and 84%-86% for the active and passive margins, respectively, for the original database. Excellent performance of the multidimensional diagrams and related discriminant functions was confirmed from 11 test studies involving Quaternary to Holocene siliciclastic sediments from known tectonic margins. The expected result of an active or passive margin was obtained, with most samples plotting correctly in the respective field.

  19. Variability in Measurement of Swimming Forces: A Meta-Analysis of Passive and Active Drag

    ERIC Educational Resources Information Center

    Havriluk, Rod

    2007-01-01

    An analysis was conducted to identify sources of true and error variance in measuring swimming drag force to draw valid conclusions about performance factor effects. Passive drag studies were grouped according to methodological differences: tow line in pool, tow line in flume, and carriage in tow tank. Active drag studies were grouped according to…

  20. VOLATILE ORGANIC COMPOUNDS AS BREATH BIOMARKERS FOR ACTIVE AND PASSIVE SMOKING

    EPA Science Inventory

    Real-time breath measurement technology was used to investigate the suitability of some volatile organic compounds (VOCs) to serve as breath biomarkers for active and passive smoking and to measure actual exposures and resulting breath concentrations for persons exposed to toba...

  1. Influence of Passive and Active Vestibular Stimulation and Balance of Young Children.

    ERIC Educational Resources Information Center

    Gabert, Trent E.; And Others

    1982-01-01

    Sixty six-to eight-year-olds with below-average scores on three balance tests received active, passive or no vestibular stimulation over a five-week period. Balance scores improved for all groups on one or more tests. Improvement could not be related to vestibular stimulation. (Author/RD)

  2. 26 CFR 1.469-3T - Passive activity credit (temporary).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... allocable to passive activities for 1988 is zero. Although B's net operating loss for the taxable year is... partner in calendar year partnership P. P purchases a building in 1987 and, in 1987, 1988, and 1989, incurs rehabilitation costs with respect to the building. The building is placed in service in the...

  3. 26 CFR 1.469-3T - Passive activity credit (temporary).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... allocable to passive activities for 1988 is zero. Although B's net operating loss for the taxable year is... partner in calendar year partnership P. P purchases a building in 1987 and, in 1987, 1988, and 1989, incurs rehabilitation costs with respect to the building. The building is placed in service in the...

  4. Passive and Active Vibrations Allow Self-Organization in Large-Scale Electromechanical Systems

    NASA Astrophysics Data System (ADS)

    Buscarino, Arturo; Fortuna, Carlo Famoso Luigi; Frasca, Mattia

    2016-06-01

    In this paper, the role of passive and active vibrations for the control of nonlinear large-scale electromechanical systems is investigated. The mathematical model of the system is discussed and detailed experimental results are shown in order to prove that coupling the effects of feedback and vibrations elicited by proper control signals makes possible to regularize imperfect uncertain large-scale systems.

  5. Passive vs. active control of rhythmic ball bouncing: the role of visual information.

    PubMed

    Siegler, Isabelle A; Bardy, Benoît G; Warren, William H

    2010-06-01

    The simple task of bouncing a ball on a racket offers a model system for studying how human actors exploit the physics and information of the environment to control their behavior. Previous work shows that people take advantage of a passively stable solution for ball bouncing but can also use perceptual information to actively stabilize bouncing. In this article, we investigate (a) active and passive contributions to the control of bouncing, (b) the visual information in the ball's trajectory, and (c) how it modulates the parameters of racket oscillation. We used a virtual ball bouncing apparatus to manipulate the coefficient of restitution alpha and gravitational acceleration g during steady-state bouncing (Experiment 1) and sudden transitions (Experiment 2) to dissociate informational variables. The results support a form of mixed control, based on the half-period of the ball's trajectory, in which racket oscillation is actively regulated on every cycle in order to keep the system in or near the passively stable region. The mixed control mode may be a general strategy for integrating passive stability with active stabilization in perception-action systems.

  6. Corticomotor excitability of wrist flexor and extensor muscles during active and passive movement.

    PubMed

    Chye, Lilian; Nosaka, Ken; Murray, Lynda; Edwards, Dylan; Thickbroom, Gary

    2010-08-01

    The excitability of the corticospinal projection to upper and lower limbs is constantly modulated during voluntary and passive movement; however a direct comparison during a comparable movement has not been reported. In the present study we used transcranial magnetic stimulation (TMS) to compare corticomotor excitability to the extensor and flexor carpi radialis (ECR/FCR) muscles of the forearm during voluntary rhythmic wrist movement (through 45 degrees of range), during a matched (for range and rhythm) passive movement of the wrist, and while the wrist was stationary (in mid-range). TMS was delivered when the wrist was in the neutral position. With passive and active movement, and for both FCR and ECR, corticomotor excitability was reduced during lengthening relative to shortening phases of movement. With active movement, this pattern was maintained and superimposed on an overall increase in excitability to both muscles that was greater for the ECR. The results favor a common pattern of excitability changes shared by extensor and flexor muscles as they undergo lengthening and shortening, which may be mediated by afferent input during both passive and active movement. This is combined with an overall increase in excitability associated with active movement that is greater for extensor muscles perhaps due to differences in the strength of the corticomotor projection to these muscles.

  7. Assimilation of active and passive microwave observations for improved estimates of soil moisture and crop growth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An Ensemble Kalman Filter-based data assimilation framework that links a crop growth model with active and passive (AP) microwave models was developed to improve estimates of soil moisture (SM) and vegetation biomass over a growing season of soybean. Complementarities in AP observations were incorpo...

  8. Passive smoking, active smoking, and education: their relationship to weight history in women in Geneva.

    PubMed Central

    Bernstein, M; Morabia, A; Héritier, S; Katchatrian, N

    1996-01-01

    OBJECTIVES: This study was undertaken to determine the relationship of education and tobacco smoke to lifetime weight history in women. METHODS: Information on passive smoking, active smoking, and weight history was collected from 928 women aged 29 to 74 years selected from the general population of Geneva, Switzerland. Multivariate analysis of variance was performed for weight, weight at age 20, and weight changes since age 20. RESULTS: Education was inversely related to weight at age 20, current weight, and weight gain since age 20. The least educated group had a current weight of 4 kg more than the most educated group. Differences across smoking categories were small: passive smokers had the highest current weight (63.4 kg) and former active smokers had the lowest (60.4 kg). Weight gain since age 20 tended to be smaller in former and current active smokers (5.5 to 7.2 kg) than in passive smokers (8.3 to 10.4 kg) and those never exposed (9.1 kg). CONCLUSIONS: In this sample, education was an important predictor of women's current weight and weight history. Passive and active smoking had little long-term effect on weight. PMID:8806379

  9. Recent Developments in Active and Passive Distributed Temperature Sensing for Soil Moisture Monitoring

    NASA Astrophysics Data System (ADS)

    Steele-Dunne, S. C.; Dong, J.; Hoes, O.; Van De Giesen, N.; Sayde, C.; Ochsner, T. E.; Selker, J. S.

    2015-12-01

    In this presentation we will review recent developments in both active and passive Distributed Temperature Sensing (DTS) for soil moisture monitoring. DTS involves using fiber-optic cables to measure temperature at sub-meter resolution along cables up to several kilometers in length. Soil thermal properties depend on soil moisture. Hence, temperature variations either in response to externally-applied heating (active) or the response to net radiation (passive) can be monitored and used to infer soil moisture. DTS occupies a unique measurement niche, potentially providing soil moisture information at sub-meter resolution over extents on the order of km at sub-daily time steps. It complements observations from point sensors to other innovative measurement techniques like cosmic ray neutron detection methods and GPS reflectometry. DTS is being developed as a tool for the validation of soil moisture observations from remote sensing and for hydrological field investigations. Here, we will discuss both technological and theoretical advances in active and passive DTS for soil moisture monitoring. We will present data from new installations in the Netherlands and the USA to illustrate recent developments. In particular, we will focus on the value of combining temperature observations from DTS with physical models using data assimilation. In addition to yielding improved soil moisture and temperature profile estimates, recent research has shown the potential to also derive information on the soil thermal and hydraulic properties. We will conclude by outlining the current challenges, with particular emphasis on combining active and passive DTS.

  10. Direct laser writing for active and passive high-Q polymer microdisks on silicon.

    PubMed

    Grossmann, Tobias; Schleede, Simone; Hauser, Mario; Beck, Torsten; Thiel, Michael; von Freymann, Georg; Mappes, Timo; Kalt, Heinz

    2011-06-01

    We report the fabrication of high-Q polymeric microdisks on silicon via direct laser writing utilizing two-photon absorption induced polymerization. The quality factors of the passive cavities are above 10(6) in the 1300 nm wavelength region. The flexible three-dimensional (3D) lithography method allows for the fabrication of different cavity thicknesses on the same substrate, useful for rapid prototyping of active and passive optical microcavities. Microdisk lasers are realized by doping the resist with dye, resulting in laser emission at visible wavelengths.

  11. Design and Development of the SMAP Microwave Radiometer Electronics

    NASA Technical Reports Server (NTRS)

    Piepmeier, Jeffrey R.; Medeiros, James J.; Horgan, Kevin A.; Brambora, Clifford K.; Estep, Robert H.

    2014-01-01

    The SMAP microwave radiometer will measure land surface brightness temperature at L-band (1413 MHz) in the presence of radio frequency interference (RFI) for soil moisture remote sensing. The radiometer design was driven by the requirements to incorporate internal calibration, to operate synchronously with the SMAP radar, and to mitigate the deleterious effects of RFI. The system design includes a highly linear super-heterodyne microwave receiver with internal reference loads and noise sources for calibration and an innovative digital signal processor and detection system. The front-end comprises a coaxial cable-based feed network, with a pair of diplexers and a coupled noise source, and radiometer front-end (RFE) box. Internal calibration is provided by reference switches and a common noise source inside the RFE. The RF back-end (RBE) downconverts the 1413 MHz channel to an intermediate frequency (IF) of 120 MHz. The IF signals are then sampled and quantized by high-speed analog-to-digital converters in the radiometer digital electronics (RDE) box. The RBE local oscillator and RDE sampling clocks are phase-locked to a common reference to ensure coherency between the signals. The RDE performs additional filtering, sub-band channelization, cross-correlation for measuring third and fourth Stokes parameters, and detection and integration of the first four raw moments of the signals. These data are packetized and sent to the ground for calibration and further processing. Here we discuss the novel features of the radiometer hardware particularly those influenced by the need to mitigate RFI.

  12. Study on development of active-passive rehabilitation system for upper limbs: Hybrid-PLEMO

    NASA Astrophysics Data System (ADS)

    Kikuchi, T.; Jin, Y.; Fukushima, K.; Akai, H.; Furusho, J.

    2009-02-01

    In recent years, many researchers have studied the potential of using robotics technology to assist and quantify the motor functions for neuron-rehabilitation. Some kinds of haptic devices have been developed and evaluated its efficiency with clinical tests, for example, upper limb training for patients with spasticity after stroke. Active-type (motor-driven) haptic devices can realize a lot of varieties of haptics. But they basically require high-cost safety system. On the other hand, passive-type (brake-based) haptic devices have inherent safety. However, the passive robot system has strong limitation on varieties of haptics. There are not sufficient evidences to clarify how the passive/active haptics effect to the rehabilitation of motor skills. In this paper, we developed an active-passive-switchable rehabilitation system with ER clutch/brake device named "Hybrid-PLEMO" in order to address these problems. In this paper, basic structures and haptic control methods of the Hybrid-PLEMO are described.

  13. Physiologic Responses Produced by Active and Passive Personal Cooling Vests

    NASA Technical Reports Server (NTRS)

    Ku, Yu-Tsuan E.; Lee, Hank C.; Montgomery, Leslie D.; Luna, Bernadette

    2000-01-01

    Personal thermoregulatory systems which provide chest cooling are used in the industrial and aerospace environments to alleviate thermal stress. However, little information is available regarding the physiologic and circulatory changes produced by routine operation of these systems. The objectives of this study were to document and compare the subjects' response to three cooling vests in their recommended configurations. The Life Enhancement Tech (LET) lightweight active cooling vest with cap, the MicroClimate Systems Change of Phase garment (MCS), and the Steele Vest were each used to cool the chest regions of 12 male and 8 female Healthy subjects (21 to 69 yr.) in this study. The subjects, seated in an upright position at normal room temperature (approx. 22 C), were tested for 60 min. with one of the cooling garments. The LET active garment had an initial coolant fluid inlet temperature of 60 F, and was ramped down to 50 F. Oral, right and left ear canal temperatures were logged manually every 5 min. Arm, leg, chest and rectal temperatures; heart rate; and respiration were recorded continuously on a U.F.I., Inc. Biolog ambulatory monitor. For men, all three vests had similar, significant cooling effects. Decreases in the average rectal temperature, oral temperature, and ear canal temperatures were approximately 0.2 C, 0.2 C and 0.1 C, respectively. In contrast to the men, the female subjects wearing the MCS and Steel vests had similar cooling responses in which the core temperature remained elevated and oral and ear canal temperatures did not drop. The LET active garment cooled most of the female subjects in this study; rectal, oral and ear temperature decreased about 0.2 C, 0.3 C and 0.3 C, respectively. These results show that the garment configurations tested do not elicit a similar thermal response in all subjects. A gender difference is evident. The LET active garment configuration was most effective in decreasing temperatures of the female subjects; the MCS

  14. [Rectal temperature in active and passive rats during desynchronosis and under melatonin treatment ].

    PubMed

    Pertsov, S S

    2005-03-01

    Effects of phase shifts in circadian rhythms and of melatonin administration on rectal temperature in rats with different activity were studied in the open-field test on 176 Wistar rats kept under conditions of natural or shifted light-darkness period. Under normal light-darkness conditions, the amplitude of diurnal variation in rectal temperature was higher in active rats as compared with passive ones. A shift in the light-darkness conditions inverted the circadian rhythm of rectal temperature and augmented the difference between daytime and night time temperatures in passive and, particularly, in active rats. Melatonin effect depended on dose and time of administration. 1 mg/kg Melatonin enhanced the amplitude of diurnal rhythms of energy metabolism in behaviourally active rats. These changes seem to contribute to adaptive reconstruction in the organism during desynchronosis. PMID:15881881

  15. "Active" and "passive" learning of three-dimensional object structure within an immersive virtual reality environment.

    PubMed

    James, K H; Humphrey, G K; Vilis, T; Corrie, B; Baddour, R; Goodale, M A

    2002-08-01

    We used a fully immersive virtual reality environment to study whether actively interacting with objects would effect subsequent recognition, when compared with passively observing the same objects. We found that when participants learned object structure by actively rotating the objects, the objects were recognized faster during a subsequent recognition task than when object structure was learned through passive observation. We also found that participants focused their study time during active exploration on a limited number of object views, while ignoring other views. Overall, our results suggest that allowing active exploration of an object during initial learning can facilitate recognition of that object, perhaps owing to the control that the participant has over the object views upon which they can focus. The virtual reality environment is ideal for studying such processes, allowing realistic interaction with objects while maintaining experimenter control. PMID:12395554

  16. Tau-based therapeutics for Alzheimer's disease: active and passive immunotherapy.

    PubMed

    Panza, Francesco; Solfrizzi, Vincenzo; Seripa, Davide; Imbimbo, Bruno P; Lozupone, Madia; Santamato, Andrea; Tortelli, Rosanna; Galizia, Ilaria; Prete, Camilla; Daniele, Antonio; Pilotto, Alberto; Greco, Antonio; Logroscino, Giancarlo

    2016-09-01

    Pharmacological manipulation of tau protein in Alzheimer's disease included microtubule-stabilizing agents, tau protein kinase inhibitors, tau aggregation inhibitors, active and passive immunotherapies and, more recently, inhibitors of tau acetylation. Animal studies have shown that both active and passive approaches can remove tau pathology and, in some cases, improve cognitive function. Two active vaccines targeting either nonphosphorylated (AAD-vac1) and phosphorylated tau (ACI-35) have entered Phase I testing. Notwithstanding, the recent discontinuation of the monoclonal antibody RG7345 for Alzheimer's disease, two other antitau antibodies, BMS-986168 and C2N-8E12, are also currently in Phase I testing for progressive supranuclear palsy. After the recent impressive results in animal studies obtained by salsalate, the dimer of salicylic acid, inhibitors of tau acetylation are being actively pursued. PMID:27485083

  17. Active and passive smoking and risk of breast cancer: a meta-analysis.

    PubMed

    Macacu, Alina; Autier, Philippe; Boniol, Mathieu; Boyle, Peter

    2015-11-01

    Studies on active and passive tobacco smoking and breast cancer have found inconsistent results. A meta-analysis of observational studies on tobacco smoking and breast cancer occurrence was conducted based on systematic searches for studies with retrospective (case-control) and prospective (cohort) designs. Eligible studies were identified, and relative risk measurements were extracted for active and passive tobacco exposures. Random-effects meta-analyses were used to compute summary relative risks (SRR). Heterogeneity of results between studies was evaluated using the (I (2)) statistics. For ever active smoking, in 27 prospective studies, the SRR for breast cancer was 1.10 (95 % CI [1.09-1.12]) with no heterogeneity (I (2) = 0 %). In 44 retrospective studies, the SRR was 1.08 (95 % CI [1.02-1.14]) with high heterogeneity (I (2) = 59 %). SRRs for current active smoking were 1.13 (95 % CI [1.09-1.17]) in 27 prospective studies and 1.08 (95 % CI [0.97-1.20]) in 22 retrospective studies. The results were stable across different subgroup analyses, notably pre/post-menopause, alcohol consumption adjustments, including/excluding passive smokers from the referent group. For ever passive smoking, in 11 prospective studies, the SRR for breast cancer was 1.07 (95 % CI [1.02-1.13]) with no heterogeneity (I (2) = 1 %). In 20 retrospective studies, the SRR was 1.30 (95 % CI [1.10-1.54]) with high heterogeneity (I (2) = 74 %). Too few prospective studies were available for meaningful subgroup analyses. There is consistent evidence for a moderate increase in the risk of breast cancer in women who smoke tobacco. The evidence for a moderate increase in risk with passive smoking is more substantial than a few years ago.

  18. Angiogenic response to passive movement and active exercise in individuals with peripheral arterial disease.

    PubMed

    Hoier, B; Walker, M; Passos, M; Walker, P J; Green, A; Bangsbo, J; Askew, C D; Hellsten, Y

    2013-12-01

    Peripheral arterial disease (PAD) is caused by atherosclerosis and is associated with microcirculatory impairments in skeletal muscle. The present study evaluated the angiogenic response to exercise and passive movement in skeletal muscle of PAD patients compared with healthy control subjects. Twenty-one PAD patients and 17 aged control subjects were randomly assigned to either a passive movement or an active exercise study. Interstitial fluid microdialysate and tissue samples were obtained from the thigh skeletal muscle. Muscle dialysate vascular endothelial growth factor (VEGF) levels were modestly increased in response to either passive movement or active exercise in both subject groups. The basal muscle dialysate level of the angiostatic factor thrombospondin-1 protein was markedly higher (P < 0.05) in PAD patients compared with the control subjects, whereas soluble VEGF receptor-1 dialysate levels were similar in the two groups. The basal VEGF protein content in the muscle tissue samples was ∼27% lower (P < 0.05) in the PAD patients compared with the control subjects. Analysis of mRNA expression for a range of angiogenic and angiostatic factors revealed a modest change with active exercise and passive movement in both groups, except for an increase (P < 0.05) in the ratio of angiopoietin-2 to angiopoietin-1 mRNA in the PAD group with both interventions. PAD patients and aged individuals showed a similar limited angiogenic response to active exercise and passive movement. The limited increase in muscle extracellular VEGF combined with an elevated basal level of thrombospondin-1 in muscle extracellular fluid of PAD patients may restrict capillary growth in these patients.

  19. Active and passive smoking and risk of breast cancer: a meta-analysis.

    PubMed

    Macacu, Alina; Autier, Philippe; Boniol, Mathieu; Boyle, Peter

    2015-11-01

    Studies on active and passive tobacco smoking and breast cancer have found inconsistent results. A meta-analysis of observational studies on tobacco smoking and breast cancer occurrence was conducted based on systematic searches for studies with retrospective (case-control) and prospective (cohort) designs. Eligible studies were identified, and relative risk measurements were extracted for active and passive tobacco exposures. Random-effects meta-analyses were used to compute summary relative risks (SRR). Heterogeneity of results between studies was evaluated using the (I (2)) statistics. For ever active smoking, in 27 prospective studies, the SRR for breast cancer was 1.10 (95 % CI [1.09-1.12]) with no heterogeneity (I (2) = 0 %). In 44 retrospective studies, the SRR was 1.08 (95 % CI [1.02-1.14]) with high heterogeneity (I (2) = 59 %). SRRs for current active smoking were 1.13 (95 % CI [1.09-1.17]) in 27 prospective studies and 1.08 (95 % CI [0.97-1.20]) in 22 retrospective studies. The results were stable across different subgroup analyses, notably pre/post-menopause, alcohol consumption adjustments, including/excluding passive smokers from the referent group. For ever passive smoking, in 11 prospective studies, the SRR for breast cancer was 1.07 (95 % CI [1.02-1.13]) with no heterogeneity (I (2) = 1 %). In 20 retrospective studies, the SRR was 1.30 (95 % CI [1.10-1.54]) with high heterogeneity (I (2) = 74 %). Too few prospective studies were available for meaningful subgroup analyses. There is consistent evidence for a moderate increase in the risk of breast cancer in women who smoke tobacco. The evidence for a moderate increase in risk with passive smoking is more substantial than a few years ago. PMID:26546245

  20. Effects of active vs. passive recovery on repeated rugby-specific exercises.

    PubMed

    Jougla, A; Micallef, J P; Mottet, D

    2010-05-01

    The aim of this study was to determine the effects of active vs. passive recovery on performance of a rugby-specific intermittent test in rugby union players. Seven male rugby players (20.6+/-0.5 yrs; 181.9+/-10.0 cm; 94.5+/-12.8 kg) performed in random order, over two separate sessions, a specific repeated-sprint rugby test, the Narbonne test (6 x 4 consecutive actions: 1, scrummaging; 2, agility sprinting; 3, tackling; 4, straight sprinting) with 30s of passive or active recovery (running at 50% of maximal aerobic speed). The Narbonne tests were completed before (pre-test) and after (post-test) a 30-min rugby match. During the Narbonne test, scrum forces, agility and sprint times, heart rate and rate of perceived exertion were measured. Scrum forces were lower in active (74.9+/-13.4 kg) than in passive recovery (90.4+/-20.9 kg), only during the post-test (p<0.05). Fatigue index (%) (p<0.05) and total sprint time (s) (p<0.01) were significantly greater in active than in passive recovery, both during the pre-test (11.5+/-5.7% vs. 6.7+/-4.5% and 18.1+/-1.3s vs. 16.9+/-0.9s) and the post-test (7.3+/-3.3% vs. 4.3+/-1.5% and 18.3+/-1.6s vs. 16.9+/-1.1s). Consequently, the results indicated that passive recovery enabled better performance during the Narbonne test. However, it is obviously impractical to suggest that players should stand still during and following repeated-sprint bouts: the players have to move to ensure they have taken an optimal position. PMID:19560972

  1. Active and Passive Sensing from Geosynchronous and Libration Orbits

    NASA Technical Reports Server (NTRS)

    Schoeberl, Mark; Raymond, Carol; Hildebrand, Peter

    2003-01-01

    The development of the LEO (EOS) missions has led the way to new technologies and new science discoveries. However, LEO measurements alone cannot cost effectively produce high time resolution measurements needed to move the science to the next level. Both GEO and the Lagrange points, L1 and L2, provide vantage points that will allow higher time resolution measurements. GEO is currently being exploited by weather satellites, but the sensors currently operating at GEO do not provide the spatial or spectral resolution needed for atmospheric trace gas, ocean or land surface measurements. It is also may be possible to place active sensors in geostationary orbit. It seems clear, that the next era in earth observation and discovery will be opened by sensor systems operating beyond near earth orbit.

  2. Active and passive smoking, IL6, ESR1, and breast cancer risk

    PubMed Central

    Curtin, Karen; Giuliano, Anna R.; Sweeney, Carol; Baumgartner, Richard; Edwards, Sandra; Wolff, Roger K.; Baumgartner, Kathy B.; Byers, Tim

    2008-01-01

    We evaluated the association between smoking and risk of breast cancer in non-Hispanic white (NHW) and Hispanic or American Indian (HAI) women living in the Southwestern United States. Data on lifetime exposure to active and passive smoke data were available from 1527 NHW cases and 1601 NHW controls; 798 HAI cases and 924 HAI controls. Interleukin 6 (IL6) and Estrogen Receptor alpha (ESR1) polymorphisms were assessed in conjunction with smoking. Pack-years of smoking (≥15) were associated with increased risk of pre-menopausal breast cancer among NHW women (OR 1.6, 95% CI 1.1–2. 4). Passive smoke increased risk of pre-menopausal breast cancer for HAI women (OR 1.9, 95% CI 1.1–3.1 everyone; OR 2.3, 95% CI 1.2–4.5 nonsmokers). HAI pre-menopausal women who were exposed to 10+ h of passive smoke per week and had the rs2069832 IL6 GG genotype had over a fourfold increased risk of breast cancer (OR 4.4, 95% CI 1.5–12.8; P for interaction 0.01). Those with the ESR1 Xba1 AA genotype had a threefold increased risk of breast cancer if they smoked ≥15 pack-years relative to non-smokers (P interaction 0.01). These data suggest that breast cancer risk is associated with active and passive smoking. PMID:17594514

  3. Comparison of epicardial deformation in passive and active isolated rabbit hearts

    NASA Astrophysics Data System (ADS)

    Ho, Andrew; Tang, Liang; Chiang, Fu-Pen; Lin, Shien-Fong

    2007-02-01

    Mechanical deformation of isolated rabbit hearts through passive inflation techniques have been a viable form of replicating heart motion, but its relation to the heart's natural active contractions remain unclear. The mechanical properties of the myocardium may show diverse characteristics while in tension and compression. In this study, epicardial strain was measured with the assistance of computer-aided speckle interferometry (CASI)1. CASI tracks the movement of clusters of particles for measuring epicardial deformation. The heart was cannulated and perfused with Tyrode's solution. Silicon carbide particles were applied onto the myocardium to form random speckle pattern images while the heart was allowed to actively contract and stabilize. High resolution videos (1000x1000 pixels) of the left ventricle were taken with a complementary metal oxide semiconductor (CMOS) camera as the heart was actively contracting through electrical pacing at various cycle lengths between 250-800 ms. A latex balloon was then inserted into the left ventricle via left atrium and videos were taken as the balloon was repeatedly inflated and deflated at controlled volumes (1-3 ml/cycle). The videos were broken down into frames and analyzed through CASI. Active contractions resulted in non-uniform circular epicardial and uniaxial contractions at different stages of the motion. In contrast, the passive heart demonstrated very uniform expansion and contraction originating from the source of the latex balloon. The motion of the active heart caused variations in deformation, but in comparison to the passive heart, had a more enigmatic displacement field. The active heart demonstrated areas of large displacement and others with relatively no displacement. Application of CASI was able to successfully distinguish the motions between the active and passive hearts.

  4. Design for active and passive flutter suppression and gust alleviation. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Karpel, M.

    1981-01-01

    Analytical design techniques for active and passive control of aeroelastic systems are based on a rational approximation of the unsteady aerodynamic loads in the entire Laplace domain, which yields matrix equations of motion with constant coefficients. Some existing schemes are reviewed, the matrix Pade approximant is modified, and a technique which yields a minimal number of augmented states for a desired accuracy is presented. The state-space aeroelastic model is used to design an active control system for simultaneous flutter suppression and gust alleviation. The design target is for a continuous controller which transfers some measurements taken on the vehicle to a control command applied to a control surface. Structural modifications are formulated in a way which enables the treatment of passive flutter suppression system with the same procedures by which active control systems are designed.

  5. A hybrid active/passive exhaust noise control system for locomotives

    NASA Astrophysics Data System (ADS)

    Remington, Paul J.; Knight, J. Scott; Hanna, Doug; Rowley, Craig

    2005-01-01

    A prototype hybrid system consisting of active and passive components for controlling far-field locomotive exhaust noise has been designed, assembled, and tested on a locomotive. The system consisted of a resistive passive silencer for controlling high-frequency broadband noise and a feedforward multiple-input, multiple-output active control system for suppressing low-frequency tonal noise. The active system used ten roof-mounted bandpass speaker enclosures with 2-12-in. speakers per enclosure as actuators, eight roof-mounted electret microphones as residual sensors, and an optical tachometer that sensed locomotive engine speed as a reference sensor. The system was installed on a passenger locomotive and tested in an operating rail yard. Details of the system are described and the near-field and far-field noise reductions are compared against the design goal. .

  6. A hybrid active/passive exhaust noise control system for locomotives.

    PubMed

    Remington, Paul J; Knight, J Scott; Hanna, Doug; Rowley, Craig

    2005-01-01

    A prototype hybrid system consisting of active and passive components for controlling far-field locomotive exhaust noise has been designed, assembled, and tested on a locomotive. The system consisted of a resistive passive silencer for controlling high-frequency broadband noise and a feedforward multiple-input, multiple-output active control system for suppressing low-frequency tonal noise. The active system used ten roof-mounted bandpass speaker enclosures with 2-12-in. speakers per enclosure as actuators, eight roof-mounted electret microphones as residual sensors, and an optical tachometer that sensed locomotive engine speed as a reference sensor. The system was installed on a passenger locomotive and tested in an operating rail yard. Details of the system are described and the near-field and far-field noise reductions are compared against the design goal.

  7. A hybrid active/passive exhaust noise control system for locomotives.

    PubMed

    Remington, Paul J; Knight, J Scott; Hanna, Doug; Rowley, Craig

    2005-01-01

    A prototype hybrid system consisting of active and passive components for controlling far-field locomotive exhaust noise has been designed, assembled, and tested on a locomotive. The system consisted of a resistive passive silencer for controlling high-frequency broadband noise and a feedforward multiple-input, multiple-output active control system for suppressing low-frequency tonal noise. The active system used ten roof-mounted bandpass speaker enclosures with 2-12-in. speakers per enclosure as actuators, eight roof-mounted electret microphones as residual sensors, and an optical tachometer that sensed locomotive engine speed as a reference sensor. The system was installed on a passenger locomotive and tested in an operating rail yard. Details of the system are described and the near-field and far-field noise reductions are compared against the design goal. PMID:15704399

  8. Active/Passive Control of Sound Radiation from Panels using Constrained Layer Damping

    NASA Technical Reports Server (NTRS)

    Gibbs, Gary P.; Cabell, Randolph H.

    2003-01-01

    A hybrid passive/active noise control system utilizing constrained layer damping and model predictive feedback control is presented. This system is used to control the sound radiation of panels due to broadband disturbances. To facilitate the hybrid system design, a methodology for placement of constrained layer damping which targets selected modes based on their relative radiated sound power is developed. The placement methodology is utilized to determine two constrained layer damping configurations for experimental evaluation of a hybrid system. The first configuration targets the (4,1) panel mode which is not controllable by the piezoelectric control actuator, and the (2,3) and (5,2) panel modes. The second configuration targets the (1,1) and (3,1) modes. The experimental results demonstrate the improved reduction of radiated sound power using the hybrid passive/active control system as compared to the active control system alone.

  9. Sustainable Passive and Active Remedial Measures of Creeping Bedrock Slopes: Two Case Studies from Austria

    NASA Astrophysics Data System (ADS)

    Moser, Michael; Weidner, Stefan

    Two case studies involving the large-scale and deep-seated creeping of slopes in southern Austria are discussed. In both instances passive and active remedial measures were applied to help mitigate the landslide hazard. At the first site, geodetic and extensometer measurements indicated movements averaging up to > 50 cm/year with a maximum of 352 cm occurring in one year. Previous active measures consisting of rigid structures were destroyed and replaced by flexible protective engineering works. The second case study involves an intensive geodetic monitoring program. Here, averaged yearly velocities are found up to > 30 cm/year. Active remedial measures consisted of stream diversion and protective engineering works. Both cases show the importance of a comprehensive passive remediation program.

  10. Life cycle assessment of active and passive groundwater remediation technologies

    NASA Astrophysics Data System (ADS)

    Bayer, Peter; Finkel, Michael

    2006-02-01

    the valuation of FGS due to the associated emissions that are harmful to human health. In view of that, environmental credits can be achieved by selecting a mineral-based wall instead of sheet piles for the funnel construction and by minimising the steel consumption for the gate construction. Granular activated carbon (GAC) is exclusively considered as the treatment material, both in-situ and on-site. Here it is identified as an additional main determinant of the relative assessment of the technologies since it is continuously consumed.

  11. [From passive to active: policies for Latin American emigrants].

    PubMed

    Maletta, H

    1988-12-01

    benefits to the country. Such factors as inclusive citizenship policies for spouses and children born abroad, provisions for absentee voting, communication and information programs, and recognition of education and professional title conferred abroad would help motivate a continuing interest in the country of origin. The 2nd policy goal should be to create concrete channels for different types of emigrant activities that would benefit the country of origin. This operational side of emigration policy would provide channels for the return to the country of capital and goods accumulated by the emigrant and would provide for cooperation in scientific endeavors, business and investment, and for social and humanitarian projects.

  12. [From passive to active: policies for Latin American emigrants].

    PubMed

    Maletta, H

    1988-12-01

    benefits to the country. Such factors as inclusive citizenship policies for spouses and children born abroad, provisions for absentee voting, communication and information programs, and recognition of education and professional title conferred abroad would help motivate a continuing interest in the country of origin. The 2nd policy goal should be to create concrete channels for different types of emigrant activities that would benefit the country of origin. This operational side of emigration policy would provide channels for the return to the country of capital and goods accumulated by the emigrant and would provide for cooperation in scientific endeavors, business and investment, and for social and humanitarian projects. PMID:12282249

  13. Life cycle assessment of active and passive groundwater remediation technologies.

    PubMed

    Bayer, Peter; Finkel, Michael

    2006-02-10

    the valuation of FGS due to the associated emissions that are harmful to human health. In view of that, environmental credits can be achieved by selecting a mineral-based wall instead of sheet piles for the funnel construction and by minimising the steel consumption for the gate construction. Granular activated carbon (GAC) is exclusively considered as the treatment material, both in-situ and on-site. Here it is identified as an additional main determinant of the relative assessment of the technologies since it is continuously consumed.

  14. Comparison of active and passive methods for radon exhalation from a high-exposure building material.

    PubMed

    Abbasi, A; Mirekhtiary, F

    2013-12-01

    The radon exhalation rates and radon concentrations in granite stones used in Iran were measured by means of a high-resolution high purity Germanium gamma-spectroscopy system (passive method) and an AlphaGUARD model PQ 2000 (active method). For standard rooms (4.0 × 5.0 m area × 2.8 height) where ground and walls have been covered by granite stones, the radon concentration and the radon exhalation rate by two methods were calculated. The activity concentrations of (226)Ra in the selected granite samples ranged from 3.8 to 94.2 Bq kg(-1). The radon exhalation rate from the calculation of the (226)Ra activity concentration was obtained. The radon exhalation rates were 1.31-7.86 Bq m(-2)h(-1). The direction measurements using an AlphaGUARD were from 218 to 1306 Bq m(-3) with a mean of 625 Bq m(-3). Also, the exhalation rates measured by the passive and active methods were compared and the results of this study were the same, with the active method being 22 % higher than the passive method. PMID:23798709

  15. Comparison of active and passive methods for radon exhalation from a high-exposure building material.

    PubMed

    Abbasi, A; Mirekhtiary, F

    2013-12-01

    The radon exhalation rates and radon concentrations in granite stones used in Iran were measured by means of a high-resolution high purity Germanium gamma-spectroscopy system (passive method) and an AlphaGUARD model PQ 2000 (active method). For standard rooms (4.0 × 5.0 m area × 2.8 height) where ground and walls have been covered by granite stones, the radon concentration and the radon exhalation rate by two methods were calculated. The activity concentrations of (226)Ra in the selected granite samples ranged from 3.8 to 94.2 Bq kg(-1). The radon exhalation rate from the calculation of the (226)Ra activity concentration was obtained. The radon exhalation rates were 1.31-7.86 Bq m(-2)h(-1). The direction measurements using an AlphaGUARD were from 218 to 1306 Bq m(-3) with a mean of 625 Bq m(-3). Also, the exhalation rates measured by the passive and active methods were compared and the results of this study were the same, with the active method being 22 % higher than the passive method.

  16. Comparison of submarine gully morphologies in passive and active margin settings

    NASA Astrophysics Data System (ADS)

    Jackson, C.; Shumaker, L.; Johnstone, S.; Graham, S. A.

    2015-12-01

    Passive and active tectonic margins have inherently different hypsometry, due to local patterns of deformation and subsequent impacts on the style of sedimentation. One way we can analyze and compare the two settings is through observation of submarine gullies, which are small channel features that form along the continental slope as it descends to the ocean floor. By documenting the geometries of gullies that have formed on passive margins and gullies that have formed on active margins, we attempt to distinguish differences in gully morphologies in these two settings. We manually mapped over 600 gullies and interfluves from shaded relief and contour maps generated from bathymetric data across the globe, including the coast of California, the Beaufort Sea, and the Black Sea. We extrapolated and plotted elevation profiles of the gullies along their downslope distance, and compared a range of gully properties, such as length, spacing, and slope, to look at the correlations among those elements of gullies and their tectonic setting. We find that gullies forming on active margins show the greatest variability in their slopes, exhibiting both the steepest and the shallowest slopes of the dataset. The slopes of the passive margin gullies fall within the range of the active margin gully slopes, but interestingly, we note patterns in the ranges of gully steepness at different localities. These results differ from our our anticipation that active margin gullies are steeper than passive margin gullies, but suggest that gullies in all settings display a variety of morphologies. Additional mapping of active margin gullies will better determine if there are morphological differences between the two settings.

  17. Comparative study of active and passive sensing with AE and PWAS transducers

    NASA Astrophysics Data System (ADS)

    Yu, Lingyu; Giurgiutiu, Victor; Yu, Jianguo; Ziehl, Paul; Zhao, Liuxian

    2012-04-01

    Monitoring of fatigue cracking in bridges using a combined passive and active scheme has been approached by the authors. Passive Acoustic Emission (AE) monitoring has shown to be able to detect crack growth behavior by picking up the stress waves resulting from the breathing of cracks while active ultrasonic pulsing can quantitatively assess structural integrity by sensing out an interrogating pulse and receive the structural reflections from the discontinuity. In this paper, we present a comparative study of active and passive sensing with two types of transducers: (a) AE transducers, and (b) embeddable piezoelectric wafer active sensors (PWAS). The study was performed experimentally on steel plates. Both pristine and damaged (notched) conditions were considered. For active sensing, pitchcatch configuration was examined in which one transducer was the transmitter and another transducer acted as the receiver. The ping signal was generated by the AE hardware/software package AEwin. For passive sensing, 0.5-mm lead breaks were executed both on top and on the edge of the plate. The comparative nature of the study was achieved by having the AE and PWAS transducers placed on the same location but on the opposite sides of the plate. The paper presents the main findings of this study in terms of (a) signal strength; (b) signal-to-noise (S/N) ratio; (c) waveform clarity; (d) waveform Fourier spectrum contents and bandwidth; (e) capability to detect and localize AE source; (f) capability to detect and localize damage. The paper performs a critical discussion of the two sensing methodologies, conventional AE transducers vs. PWAS transducers.

  18. Telencephalic neural activation following passive avoidance learning in a terrestrial toad.

    PubMed

    Puddington, Martín M; Daneri, M Florencia; Papini, Mauricio R; Muzio, Rubén N

    2016-12-15

    The present study explores passive avoidance learning and its neural basis in toads (Rhinella arenarum). In Experiment 1, two groups of toads learned to move from a lighted compartment into a dark compartment. After responding, animals in the experimental condition were exposed to an 800-mM strongly hypertonic NaCl solution that leads to weight loss. Control animals received exposure to a 300-mM slightly hypertonic NaCl solution that leads to neither weight gain nor loss. After 10 daily acquisition trials, animals in the experimental group showed significantly longer latency to enter the dark compartment. Additionally, 10 daily trials in which both groups received the 300-mM NaCl solution after responding eliminated this group effect. Thus, experimental animals showed gradual acquisition and extinction of a passive avoidance respond. Experiment 2 replicated the gradual acquisition effect, but, after the last trial, animals were sacrificed and neural activation was assessed in five brain regions using AgNOR staining for nucleoli-an index of brain activity. Higher activation in the experimental animals, relative to controls, was observed in the amygdala and striatum. Group differences in two other regions, lateral pallium and septum, were borderline, but nonsignificant, whereas group differences in the medial pallium were nonsignificant. These preliminary results suggest that a striatal-amygdala activation could be a key component of the brain circuit controlling passive avoidance learning in amphibians. The results are discussed in relation to the results of analogous experiments with other vertebrates.

  19. Municipal waste stabilization in a reactor with an integrated active and passive aeration system.

    PubMed

    Kasinski, Slawomir; Slota, Monika; Markowski, Michal; Kaminska, Anna

    2016-04-01

    To test whether an integrated passive and active aeration system could be an effective solution for aerobic decomposition of municipal waste in technical conditions, a full-scale composting reactor was designed. The waste was actively aerated for 5d, passively aerated for 35 d, and then actively aerated for 5d, and the entire composting process was monitored. During the 45-day observation period, changes in the fractional, morphological and physico-chemical characteristics of the waste at the top of the reactor differed from those in the center of the reactor. The fractional and morphological analysis made during the entire process of stabilization, showed the total reduction of organic matter measured of 82 wt% and 86 wt% at the respective depths. The reduction of organic matter calculated using the results of Lost of Ignition (LOI) and Total Organic Carbon (TOC) showed, respectively, 40.51-46.62% organic matter loss at the top and 45.33-53.39% in the center of the reactor. At the end of the process, moisture content, LOI and TOC at the top were 3.29%, 6.10% and 4.13% higher, respectively, than in the center. The results showed that application of passive aeration in larger scale simultaneously allows the thermophilic levels to be maintained during municipal solid waste composting process while not inhibiting microbial activity in the reactor.

  20. Detection Thresholds of Falling Snow from Satellite-Borne Active and Passive Sensors

    NASA Technical Reports Server (NTRS)

    Jackson, Gail

    2012-01-01

    Precipitation, including rain and snow, is a critical part of the Earth's energy and hydrology cycles. In order to collect information on the complete global precipitation cycle and to understand the energy budget in terms of precipitation, uniform global estimates of both liquid and frozen precipitation must be collected. Active observations of falling snow are somewhat easier to estimate since the radar will detect the precipitation particles and one only needs to know surface temperature to determine if it is liquid rain or snow. The challenges of estimating falling snow from passive spaceborne observations still exist though progress is being made. While these challenges are still being addressed, knowledge of their impact on expected retrieval results is an important key for understanding falling snow retrieval estimations. Important information to assess falling snow retrievals includes knowing thresholds of detection for active and passive sensors, various sensor channel configurations, snow event system characteristics, snowflake particle assumptions, and surface types. For example, can a lake effect snow system with low (2.5 km) cloud tops having an ice water content (Iwe) at the surface of 0.25 g m-3 and dendrite snowflakes be detected? If this information is known, we can focus retrieval efforts on detectable storms and concentrate advances on achievable results. Here, the focus is to determine thresholds of detection for falling snow for various snow conditions over land and lake surfaces. The analysis relies on simulated Weather Research Forecasting (WRF) simulations of falling snow cases since simulations provide all the information to determine the measurements from space and the ground truth. Results are presented for active radar at Ku, Ka, and W-band and for passive radiometer channels from 10 to 183 GHz (Skofronick-Jackson, et al. submitted to IEEE TGRS, April 2012). The notable results show: (1) the W-Band radar has detection thresholds more

  1. Passive and Active Detection of Clouds: Comparisons between MODIS and GLAS Observations

    NASA Technical Reports Server (NTRS)

    Mahesh, Ashwin; Gray, Mark A.; Palm, Stephen P.; Hart, William D.; Spinhirne, James D.

    2003-01-01

    The Geoscience Laser Altimeter System (GLAS), launched on board the Ice, Cloud and Land Elevation Satellite in January 2003 provides space-borne laser observations of atmospheric layers. GLAS provides opportunities to validate passive observations of the atmosphere for the first time from space with an active optical instrument. Data from the Moderate Resolution Imaging Spectrometer aboard the Aqua satellite is examined along with GLAS observations of cloud layers. In more than three-quarters of the cases, MODIS scene identification from spectral radiances agrees with GLAS. Disagreement between the two platforms is most significant over snow-covered surfaces in the northern hemisphere. Daytime clouds detected by GLAS are also more easily seen in the MODIS data as well, compared to observations made at night. These comparisons illustrate the capabilities of active remote sensing to validate and assess passive measurements, and also to complement them in studies of atmospheric layers.

  2. Adaptation to visual and proprioceptive rearrangement - Origin of the differential effectiveness of active and passive movements

    NASA Technical Reports Server (NTRS)

    Lackner, J. R.

    1977-01-01

    Experiments were conducted to measure and compare the accuracy with which subjects pointed to visual targets before and after an exposure period in which they received systematic proprioceptive misinformation about the locations of visual targets. The crucial factor determining whether adaptation will be elicited is shown to be the presence of a discordance in the positional information being conveyed over two different sensory modalities. Another experiment was carried out to study the effectiveness of active and passive movements in eliciting adaptation when the subjects were exposed to a systematic discordance between the visual and proprioceptive locations of external targets without being permitted sight of their hands. Superiority of active over passive movements in producing adaptation to visual rearrangement is due to the greater accuracy of position sense information about voluntarily moved limbs, partly derived from the contribution of muscle afferent signals.

  3. Simulation of active and passive millimeter-wave (35 GHz) sensors by time series analysis

    NASA Astrophysics Data System (ADS)

    Strenzwilk, D. F.; Maruyama, R. T.

    1982-11-01

    Analog voltage signals from a millimeter-wave (MMW) radiometer (passive sensor) and radar (active sensor) were collected over varying grassy terrains at Aberdeen Proving Ground (APG), Maryland in July 1980. These measurements were made as part of continuing studies of MMW sensors for smart munitions. The signals were digitized at a rate of 2,000 observations per second and then analyzed by the Box and Jenkins time series approach. This analysis reports on the characterization of these data sets. The passive time series signals resulted in a simple autoregressive-moving average process, similar to a previous set of data taken at Rome Air Development Center in Rome, N.Y. by Ballistic Research Laboratory. On the other hand, the radar data (active sensor) required a data transformation to enhance the analysis. In both cases the signals were well characterized using the Box-Jenkins time series approach.

  4. Simulation of Series Active and Passive Power Filter Combination System to Mitigate Current Source Harmonics

    NASA Astrophysics Data System (ADS)

    Yusof, Yushaizad; Rahim, Nasrudin Abd.

    2009-08-01

    This paper discusses a combination three phase system of series active power filter and passive power filter used to mitigate current source harmonics produced by a three phase diode rectifier with capacitive loads. A control method based on synchronous reference frame (SRF) is implemented to compensate for the current harmonics. Computer simulation and modelling of the combined filter system is carried out using Matlab/Simulink Power System Blockset (PSB) software. The single tuned passive power filters suppress 5th and 7th order current harmonics, while the series active power filter acts as a harmonic isolator between the source and load. Hence, the proposed system performs very well in mitigating source current harmonics to the level that comply the harmonic standard such as IEEE 519-1992.

  5. Active and passive calcium transport systems in plant cells. Progress report, May 1986--January 1991

    SciTech Connect

    Sze, H.

    1991-12-31

    The ability to change cytoplasmic Ca{sup 2+} levels ([Ca{sup 2+}]) by cells has made this cation a key regulator of many biological processes. Cytoplasmic [Ca{sup 2+}] is determined by the coordination of passive Ca{sup 2+} fluxes which increase cytosolic [Ca{sup 2+}] and active Ca{sup 2+} transport systems that lower cytosolic [Ca{sup 2+}]. The mechanisms by which plant cells achieve this is poorly understood. We have initially used isolated vesicles from the plasma membrane or organellar membranes to study Ca{sup 2+} transport systems in oat roots (a monocot) and carrot suspension cells (a dicot). The objectives of the proposal were to identify and characterize active (energy-dependent) and passive calcium transport systems that work together to regulate calcium levels in the cytoplasm of plant cells.

  6. Active-passive correlation spectroscopy - A new technique for identifying ocean color algorithm spectral regions

    NASA Technical Reports Server (NTRS)

    Hoge, F. E.; Swift, R. N.

    1986-01-01

    A new active-passive airborne data correlation technique has been developed which allows the validation of existing in-water oceoan color algorithms and the rapid search, identification, and evaluation of new sensor band locations and algorithm wavelength intervals. Thus far, applied only in conjunction with the spectral curvature algorithm (SCA), the active-passive correlation spectroscopy (APCS) technique shows that (1) the usual 490-nm (center-band) chlorophyll SCA could satisfactorily be placed anywhere within the nominal 460-510-nm interval, and (2) two other spectral regions, 645-660 and 680-695 nm, show considerable promise for chlorophyll pigment measurement. Additionally, the APCS method reveals potentially useful wavelength regions (at 600 and about 670 nm) of very low chlorophyll-in-water spectral curvature into which accessory pigment algorithms for phycoerythrin might be carefully positioned. In combination, the APCS and SCA methods strongly suggest that significant information content resides within the seemingly featureless ocean color spectrum.

  7. A multifrequency evaluation of active and passive microwave sensors for oil spill detection and assessment

    NASA Technical Reports Server (NTRS)

    Fenner, R. G.; Reid, S. C.; Solie, C. H.

    1980-01-01

    An evaluation is given of how active and passive microwave sensors can best be used in oil spill detection and assessment. Radar backscatter curves taken over oil spills are presented and their effect on synthetic aperture radar (SAR) imagery are discussed. Plots of microwave radiometric brightness variations over oil spills are presented and discussed. Recommendations as to how to select the best combination of frequency, viewing angle, and sensor type for evaluation of various aspects of oil spills are also discussed.

  8. Compact and highly-efficient polarization independent vertical resonant couplers for active-passive monolithic integration.

    PubMed

    Galarza, Marko; Van Thourhout, Dries; Baets, Roel; Lopez-Amo, Manuel

    2008-06-01

    Compact low-loss polarization independent vertical coupling between a 1.55 microm InGaAsP bulk active waveguide and a passive waveguide based on bimodal interference is presented. Simulation results show low coupling loss (<0.1 dB) over coupler lengths more than 5 times shorter than using the adiabatic design. The concept avoids submicron photolithographic features and shows acceptable fabrication tolerances.

  9. The correlation of active and passive microwave data for the Skylab S-193 sensor

    NASA Technical Reports Server (NTRS)

    Krishen, Kumar

    1993-01-01

    This paper presents the results of the correlation analysis of the Skylab S-193 13.9 GHz Radiometer/Scatterometer data. Computer analysis of the S-193 data shows more than 50 percent of the radiometer and scatterometer data are uncorrelated. The correlation coefficients computed for the data gathered over various ground scenes indicates the desirability of using both active and passive sensors for the determination of various Earth phenomena.

  10. The Correlation of Active and Passive Microwave Outputs for the Skylab S-193 Sensor

    NASA Technical Reports Server (NTRS)

    Krishen, K.

    1976-01-01

    This paper presents the results of the correlation analysis of the Skylab S-193 13.9 GHz Radiometer/Scatterometer data. Computer analysis of the S-193 data shows more than 50 percent of the radiometer and scatterometer data are uncorrelated. The correlation coefficients computed for the data gathered over various ground scenes indicates the desirability of using both active and passive sensors for the determination of various Earth phenomena.

  11. The Effect of Passive versus Active Recovery on Power Output over Six Repeated Wingate Sprints

    ERIC Educational Resources Information Center

    Lopez, Egla-Irina D.; Smoliga, James M.; Zavorsky, Gerald S.

    2014-01-01

    Purpose: The aim of this study was to examine the effect of active versus passive recovery on 6 repeated Wingate tests (30-s all-out cycling sprints on a Velotron ergometer). Method: Fifteen healthy participants aged 29 (SD = 8) years old (body mass index = 23 [3] kg/m[superscript 2]) participated in 3 sprint interval training sessions separated…

  12. Active and Passive Smoking and the Incidence of Asthma in the Black Women’s Health Study

    PubMed Central

    Castro-Webb, Nelsy; Yu, Jeffrey; O’Connor, George T.; Palmer, Julie R.; Rosenberg, Lynn

    2015-01-01

    Rationale: Evidence linking active or passive smoking to the incidence of adult-onset asthma is inconsistent with both positive and inverse associations being reported. Most previous studies of active smoking have not accounted for passive smoke exposure, which may have introduced bias. Objectives: To assess the separate associations of active and passive smoking to the incidence of adult-onset asthma in the U.S. Black Women’s Health Study, a prospective cohort of African American women followed since 1995 with mailed biennial questionnaires. Methods: Active smoking status was reported at baseline and updated on all follow-up questionnaires. Passive smoke exposure during childhood, adolescence, and adulthood was ascertained in 1997. Asthma cases comprised women who reported doctor-diagnosed asthma with concurrent asthma medication use. Cox regression models were used to derive multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) for former and current smoking and for passive smoking among nonsmokers compared with a reference category of never active or passive smokers. Measurements and Main Results: Among 46,182 participants followed from 1995 to 2011, 1,523 reported incident asthma. The multivariable HRs for former active smoking, current active smoking, and passive smoking only were, respectively, 1.36 (95% CI, 1.11–1.67), 1.43 (95% CI, 1.15–1.77), and 1.21 (95% CI, 1.00–1.45), compared with never active/passive smoking. Conclusions: In this large population with 16 years of follow-up, active smoking increased the incidence of adult-onset asthma, and passive smoke exposure increased the risk among nonsmokers. Continued efforts to reduce exposure to tobacco smoke may have a beneficial effect on the incidence of adult-onset asthma. PMID:25387276

  13. Bumblebees minimize control challenges by combining active and passive modes in unsteady winds

    PubMed Central

    Ravi, Sridhar; Kolomenskiy, Dmitry; Engels, Thomas; Schneider, Kai; Wang, Chun; Sesterhenn, Jörn; Liu, Hao

    2016-01-01

    The natural wind environment that volant insects encounter is unsteady and highly complex, posing significant flight-control and stability challenges. It is critical to understand the strategies insects employ to safely navigate in natural environments. We combined experiments on free flying bumblebees with high-fidelity numerical simulations and lower-order modeling to identify the mechanics that mediate insect flight in unsteady winds. We trained bumblebees to fly upwind towards an artificial flower in a wind tunnel under steady wind and in a von Kármán street formed in the wake of a cylinder. Analysis revealed that at lower frequencies in both steady and unsteady winds the bees mediated lateral movement with body roll - typical casting motion. Numerical simulations of a bumblebee in similar conditions permitted the separation of the passive and active components of the flight trajectories. Consequently, we derived simple mathematical models that describe these two motion components. Comparison between the free-flying live and modeled bees revealed a novel mechanism that enables bees to passively ride out high-frequency perturbations while performing active maneuvers at lower frequencies. The capacity of maintaining stability by combining passive and active modes at different timescales provides a viable means for animals and machines to tackle the challenges posed by complex airflows. PMID:27752047

  14. Evaluation of multiple-frequency, active and passive acoustics as surrogates for bedload transport

    USGS Publications Warehouse

    Wood, Molly S.; Fosness, Ryan L.; Pachman, Gregory; Lorang, Mark; Tonolla, Diego

    2015-01-01

    The use of multiple-frequency, active acoustics through deployment of acoustic Doppler current profilers (ADCPs) shows potential for estimating bedload in selected grain size categories. The U.S. Geological Survey (USGS), in cooperation with the University of Montana (UM), evaluated the use of multiple-frequency, active and passive acoustics as surrogates for bedload transport during a pilot study on the Kootenai River, Idaho, May 17-18, 2012. Four ADCPs with frequencies ranging from 600 to 2000 kHz were used to measure apparent moving bed velocities at 20 stations across the river in conjunction with physical bedload samples. Additionally, UM scientists measured the sound frequencies of moving particles with two hydrophones, considered passive acoustics, along longitudinal transects in the study reach. Some patterns emerged in the preliminary analysis which show promise for future studies. Statistically significant relations were successfully developed between apparent moving bed velocities measured by ADCPs with frequencies 1000 and 1200 kHz and bedload in 0.5 to 2.0 mm grain size categories. The 600 kHz ADCP seemed somewhat sensitive to the movement of gravel bedload in the size range 8.0 to 31.5 mm, but the relation was not statistically significant. The passive hydrophone surveys corroborated the sample results and could be used to map spatial variability in bedload transport and to select a measurement cross-section with moving bedload for active acoustic surveys and physical samples.

  15. Ethnic differences in thermoregulatory responses during resting, passive and active heating: application of Werner's adaptation model.

    PubMed

    Lee, Joo-Young; Wakabayashi, Hitoshi; Wijayanto, Titis; Hashiguchi, Nobuko; Saat, Mohamed; Tochihara, Yutaka

    2011-12-01

    For the coherent understanding of heat acclimatization in tropical natives, we compared ethnic differences between tropical and temperate natives during resting, passive and active heating conditions. Experimental protocols included: (1) a resting condition (an air temperature of 28°C with 50% RH), (2) a passive heating condition (28°C with 50% RH; leg immersion in a hot tub at a water temperature of 42°C), and (3) an active heating condition (32°C with 70% RH; a bicycle exercise). Morphologically and physically matched tropical natives (ten Malaysian males, MY) and temperate natives (ten Japanese males, JP) participated in all three trials. The results saw that: tropical natives had a higher resting rectal temperature and lower hand and foot temperatures at rest, smaller rise of rectal temperature and greater temperature rise in bodily extremities, and a lower sensation of thirst during passive and active heating than the matched temperate natives. It is suggested that tropical natives' homeostasis during heating is effectively controlled with the improved stability in internal body temperature and the increased capability of vascular circulation in extremities, with a lower thirst sensation. The enhanced stability of internal body temperature and the extended thermoregulatory capability of vascular circulation in the extremities of tropical natives can be interpreted as an interactive change to accomplish a thermal dynamic equilibrium in hot environments. These heat adaptive traits were explained by Wilder's law of initial value and Werner's process and controller adaptation model.

  16. Initial evaluation of an active/passive structural neural system for health monitoring of composite materials

    NASA Astrophysics Data System (ADS)

    Kirikera, G. R.; Lee, J. W.; Schulz, M. J.; Ghoshal, A.; Sundaresan, M. J.; Allemang, R. J.; Shanov, V. N.; Westheider, H.

    2006-10-01

    Structural health monitoring is an underlying technology that can help to ensure safe operation and provide cost effective maintenance of advanced composite structures. While several general methods of health monitoring have evolved in recent years, there is still the goal of reducing the overall cost of applying health monitoring to large structures. Data acquisition hardware typically consumes most of the investment in a structural monitoring system. On a conventional system based on acoustic emission monitoring, a separate high sampling rate data acquisition channel is needed for each sensor to convert analog signals to digital signals to locate damage. Other methods of damage detection are likewise complicated, and require many sensors and actuators, auxiliary signal processing, and data storage instrumentation. This paper proposes a structural neural system that uses firing of sensor neurons to reduce the number of data acquisition channels needed for damage detection. The neural system can perform passive acoustic emission sensing or active wave propagation monitoring. A prototype structural neural system with four sensor inputs was built and tested, and experimental results are presented in the paper. One signal output from the structural neural system is used to predict the location of damage. A second signal provides the time domain response of the sensors. Therefore, passive and active health monitoring can be performed using two channels of data acquisition. The structural neural system significantly reduces the data acquisition hardware required for health monitoring, and combines some of the advantages that exist individually for passive and active health monitoring.

  17. Comparing passive and active hearing: spectral analysis of transient sounds in bats.

    PubMed

    Goerlitz, Holger R; Hübner, Mathias; Wiegrebe, Lutz

    2008-06-01

    In vision, colour constancy allows the evaluation of the colour of objects independent of the spectral composition of a light source. In the auditory system, comparable mechanisms have been described that allows the evaluation of the spectral shape of sounds independent of the spectral composition of ambient background sounds. For echolocating bats, the evaluation of spectral shape is vitally important both for the analysis of external sounds and the analysis of the echoes of self-generated sonar emissions. Here, we investigated how the echolocating bat Phyllostomus discolor evaluates the spectral shape of transient sounds both in passive hearing and in echolocation as a specialized mode of active hearing. Bats were trained to classify transients of different spectral shape as low- or highpass. We then assessed how the spectral shape of an ambient background noise influenced the spontaneous classification of the transients. In the passive-hearing condition, the bats spontaneously changed their classification boundary depending on the spectral shape of the background. In the echo-acoustic condition, the classification boundary did not change although the background- and spectral-shape manipulations were identical in the two conditions. These data show that auditory processing differs between passive and active hearing: echolocation represents an independent mode of active hearing with its own rules of auditory spectral analysis.

  18. Effects of Active Versus Passive Group Music Therapy on Preadolescents with Emotional, Learning, and Behavioral Disorders.

    PubMed

    Montello; Coons

    1999-01-01

    This study attempted to compare the behavioral effects of active, rhythm-based group music therapy vs. those of passive, listening-based group music therapy on preadolescents with emotional, learning, and behavioral disorders. It was hypothesized that preadolescents who participated in active music therapy would more significantly improve target behaviors than those involved in passive music therapy. Achenbach's Teacher Report Form (TRF) was used to confirm changes among subjects in attention, motivation, and hostility as rated by homeroom teachers. Twelve music therapy sessions were conducted over a 4-month period with three different groups of subjects (n = 16), with two groups participating in active music therapy and the other receiving passive music therapy. Results indicate that subjects improved significantly after receiving both music therapy interventions. The most significant change in subjects was found on the aggression/hostility scale. These results suggest that group music therapy can facilitate the process of serf-expression in emotionally disturbed/learning disabled adolescents and provide a channel for transforming frustration, anger, and aggression into the experience of creativity and self-mastery. Discussion of results also includes recommendations for chousing one music therapy approach over another based on personality types and/or clinical diagnoses of subjects.

  19. Comparing effects of active and passive restoration on the Middle Fork John Day River, NE Oregon

    NASA Astrophysics Data System (ADS)

    McDowell, P. F.; Goslin, M.

    2015-12-01

    Since 2000, cattle grazing has been eliminated on over 14 km of the upper Middle Fork John Day. Starting in 2008, active restoration (log structures with dug pools, woody vegetation planting, and modifications to increase channel-floodplain hydrologic connectivity) was implemented on nearly 6 km within the cattle exclosure length. Implementation of active and passive restoration strategies in the same and adjacent reaches allows comparison of these two approaches. We have been monitoring these reaches since 2008. Unexpectedly in response to grazing exclosure, a native sedge, Carex nudata (torrent sedge), has exploded in population. C. nudata grows in the active channel, anchoring itself tightly to the gravel-cobble river bed with a dense root network. As a result, C. nudata has changed erosion and sedimentation patterns including bank erosion, channel bed scour, and island formation. We present data on fish cover increases due to C. nudata and log structures, and on channel complexity before and after restoration. Both active and passive restorations are increasing channel complexity and juvenile fish cover, although in different ways. Fish cover provided by active and passive restoration are similar in area but different in depth and position, with C. nudata fish cover generally shallower and partly mid-channel. Residual pool depth is larger in log structure pools than in C. nudata scour pools, but C. nudata pools are more numerous in some reaches. By producing frequent, small scour features and small islands, it can be argued that C. nudata is increasing hydraulic complexity more than the large, meander-bend pools at log structures, but this is hard to quantify. C. nudata has also stabilized active bars, perhaps changing the bedload sediment budget. Positive habitat benefits of active restoration appear to be greater in the short term, but over the long term (20 years or more) effects of C. nudata may be comparable or greater.

  20. Application of active and passive neutron non destructive assay methods to concrete radioactive waste drums

    NASA Astrophysics Data System (ADS)

    Jallu, F.; Passard, C.; Brackx, E.

    2011-09-01

    This paper deals with the application of non-destructive neutron measurement methods to control and characterize 200 l radioactive waste drums filled with a concrete matrix. Due to its composition, and particularly to hydrogen, concrete penalizes the use of such methods to quantify uranium (U) and plutonium (Pu) components, which are mainly responsible of the α-activity of the waste. The determination of the alpha activity is the main objective of neutron measurements, in view to verify acceptance criteria in surface storage. Calibration experiments of the Active Neutron Interrogation (ANI) method lead to Detection Limit Masses (DLM) of about 1 mg of 239Pu eff in the total counting mode, and of about 10 mg of 239Pu eff in the coincidence counting mode, in case of a homogeneous Pu source and measurement times between one and two hours. Monte Carlo calculation results show a very satisfactory agreement between experimental values and calculated ones. Results of the application of passive and active neutron methods to control two real drums are presented in the last part of the paper. They show a good agreement between measured data and values declared by the waste producers. The main difficulties that had to be overcome are the low neutron signal in passive and active coincidence counting modes due to concrete, the analysis of the passive neutron signal in presence of 244Cm in the drum, which is a strong spontaneous fission neutron emitter, the variation of the active background with the concrete composition, and the analysis of the active prompt neutron signal due to the simultaneous presence of U and Pu in the drums.

  1. Active Flexion in Weight Bearing Better Correlates with Functional Outcomes of Total Knee Arthroplasty than Passive Flexion

    PubMed Central

    Song, Young Dong; Jain, Nimash; Kang, Yeon Gwi; Kim, Tae Yune

    2016-01-01

    Purpose Correlations between maximum flexion and functional outcomes in total knee arthroplasty (TKA) patients are reportedly weak. We investigated whether there are differences between passive maximum flexion in nonweight bearing and other types of maximum flexion and whether the type of maximum flexion correlates with functional outcomes. Materials and Methods A total of 210 patients (359 knees) underwent preoperative evaluation and postoperative follow-up evaluations (6, 12, and 24 months) for the assessment of clinical outcomes including maximum knee flexion. Maximum flexion was measured under five conditions: passive nonweight bearing, passive weight bearing, active nonweight bearing, and active weight bearing with or without arm support. Data were analyzed for relationships between passive maximum flexion in nonweight bearing by Pearson correlation analyses, and a variance comparison between measurement techniques via paired t test. Results We observed substantial differences between passive maximum flexion in nonweight bearing and the other four maximum flexion types. At all time points, passive maximum flexion in nonweight bearing correlated poorly with active maximum flexion in weight bearing with or without arm support. Active maximum flexion in weight bearing better correlated with functional outcomes than the other maximum flexion types. Conclusions Our study suggests active maximum flexion in weight bearing should be reported together with passive maximum flexion in nonweight bearing in research on the knee motion arc after TKA. PMID:27274468

  2. Brain activation patterns resulting from learning letter forms through active self-production and passive observation in young children

    PubMed Central

    Kersey, Alyssa J.; James, Karin H.

    2013-01-01

    Although previous literature suggests that writing practice facilitates neural specialization for letters, it is unclear if this facilitation is driven by the perceptual feedback from the act of writing or the actual execution of the motor act. The present study addresses this issue by measuring the change in BOLD signal in response to hand-printed letters, unlearned cursive letters, and cursive letters that 7-year-old children learned actively, by writing, and passively, by observing an experimenter write. Brain activation was assessed using fMRI while perceiving letters—in both cursive and manuscript forms. Results showed that active training led to increased recruitment of the sensori-motor network associated with letter perception as well as the insula and claustrum, but passive observation did not. This suggests that perceptual networks for newly learned cursive letters are driven by motor execution rather than by perceptual feedback. PMID:24069007

  3. Brain activation patterns resulting from learning letter forms through active self-production and passive observation in young children.

    PubMed

    Kersey, Alyssa J; James, Karin H

    2013-01-01

    Although previous literature suggests that writing practice facilitates neural specialization for letters, it is unclear if this facilitation is driven by the perceptual feedback from the act of writing or the actual execution of the motor act. The present study addresses this issue by measuring the change in BOLD signal in response to hand-printed letters, unlearned cursive letters, and cursive letters that 7-year-old children learned actively, by writing, and passively, by observing an experimenter write. Brain activation was assessed using fMRI while perceiving letters-in both cursive and manuscript forms. Results showed that active training led to increased recruitment of the sensori-motor network associated with letter perception as well as the insula and claustrum, but passive observation did not. This suggests that perceptual networks for newly learned cursive letters are driven by motor execution rather than by perceptual feedback.

  4. A large difference in the progenitor masses of active and passive galaxies in the EAGLE simulation

    NASA Astrophysics Data System (ADS)

    Clauwens, Bart; Franx, Marijn; Schaye, Joop

    2016-11-01

    Cumulative number density matching of galaxies is a method to observationally connect descendent galaxies to their typical main progenitors at higher redshifts and thereby to assess the evolution of galaxy properties. The accuracy of this method is limited due to galaxy merging and scatter in the stellar mass growth history of individual galaxies. Behroozi et al. (2013) have introduced a refinement of the method, based on abundance matching of observed galaxies to the Bolshoi dark-matter-only simulation. The EAGLE cosmological hydro-simulation is well suited to test this method, because it reproduces the observed evolution of the galaxy stellar mass function and the passive fraction. We find agreement with the Behroozi et al. (2013) method for the complete sample of main progenitors of z = 0 galaxies, but we also find a strong dependence on the current star formation rate. Passive galaxies with a stellar mass up to 10^10.75 Msun have a completely different median mass history than active galaxies of the same mass. This difference persists if we only select central galaxies. This means that the cumulative number density method should be applied separately to active and passive galaxies. Even then, the typical main progenitor of a z = 0 galaxy already spans two orders of magnitude in stellar mass at z = 2.

  5. Separating Active and Passive Influences on Stomatal Control of Transpiration[OPEN

    PubMed Central

    McAdam, Scott A.M.; Brodribb, Timothy J.

    2014-01-01

    Motivated by studies suggesting that the stomata of ferns and lycophytes do not conform to the standard active abscisic acid (ABA) -mediated stomatal control model, we examined stomatal behavior in a conifer species (Metasequoia glyptostroboides) that is phylogenetically midway between the fern and angiosperm clades. Similar to ferns, daytime stomatal closure in response to moderate water stress seemed to be a passive hydraulic process in M. glyptostroboides immediately alleviated by rehydrating excised shoots. Only after prolonged exposure to more extreme water stress did active ABA-mediated stomatal closure become important, because foliar ABA production was triggered after leaf turgor loss. The influence of foliar ABA on stomatal conductance and stomatal aperture was highly predictable and additive with the passive hydraulic influence. M. glyptostroboides thus occupies a stomatal behavior type intermediate between the passively controlled ferns and the characteristic ABA-dependent stomatal closure described in angiosperm herbs. These results highlight the importance of considering phylogeny as a major determinant of stomatal behavior. PMID:24488969

  6. Passive exposures of children to volatile trihalomethanes during domestic cleaning activities of their parents

    SciTech Connect

    Andra, Syam S.; Charisiadis, Pantelis; Karakitsios, Spyros; Sarigiannis, Denis A.; Makris, Konstantinos C.

    2015-01-15

    Domestic cleaning has been proposed as a determinant of trihalomethanes (THMs) exposure in adult females. We hypothesized that parental housekeeping activities could influence children's passive exposures to THMs from their mere physical presence during domestic cleaning. In a recent cross-sectional study (n=382) in Cyprus [41 children (<18y) and 341 adults (≥18y)], we identified 29 children who met the study's inclusion criteria. Linear regression models were applied to understand the association between children sociodemographic variables, their individual practices influencing ingestion and noningestion exposures to ΣTHMs, and their urinary THMs levels. Among the children-specific variables, age alone showed a statistically significant inverse association with their creatinine-adjusted urinary ΣTHMs (r{sub S}=−0.59, p<0.001). A positive correlation was observed between urinary ΣTHMs (ng g{sup −1}) of children and matched-mothers (r{sub S}=0.52, p=0.014), but this was not the case for their matched-fathers (r{sub S}=0.39, p=0.112). Time spent daily by the matched-mothers for domestic mopping, toilet and other cleaning activities using chlorine-based cleaning products was associated with their children's urinary THMs levels (r{sub S}=0.56, p=0.007). This trend was not observed between children and their matched-fathers urinary ΣTHMs levels, because of minimum amount of time spent by the latter in performing domestic cleaning. The proportion of variance of creatinine-unadjusted and adjusted urinary ΣTHMs levels in children that was explained by the matched-mothers covariates was 76% and 74% (p<0.001), respectively. A physiologically-based pharmacokinetic model adequately predicted urinary chloroform excretion estimates, being consistent with the corresponding measured levels. Our findings highlighted the influence of mothers' domestic cleaning activities towards enhancing passive THMs exposures of their children. The duration of such activities could be

  7. Three-dimensional integration of passive and active polymer waveguide devices

    NASA Astrophysics Data System (ADS)

    Garner, Sean Matthew

    This thesis presents the design, fabrication, and experimental results of three dimensionally integrated optics. This vertical and horizontal integration of polymer waveguide structures increases the integration density, reduces interconnection routing difficulties, and expands the functional diversity of adjacent devices. The devices discussed depend on the fabrication of vertical slopes using unconventional photolithography and reactive ion etching techniques. The slopes produced allow fully functional three dimensionally integrated optics that incorporate both passive and active waveguide elements. Passive structures such as vertical waveguide bends, power splitters, and polarization splitters enable three dimensional routing of the optical power among multiple vertical levels. Single mode vertical waveguide bends are demonstrated with polarization insensitive excess losses of 0.2dB. These waveguide structures incorporated bending angles up to 1.5°. Three dimensional 1 x 4 splitters, possess excess losses of 0.5dB and show the ability to fabricate complex waveguide structures in both the horizontal and vertical directions. These vertical power splitters showed controllable power splitting ratios in the output waveguides by controlling the spin cast film thickness within 0.5μM and the slope angle within 0.5°. The vertical polarization splitters incorporated birefringent polymer materials to create an adiabatic mode splitter. These possessed power extinction ratios of about 15dB for both input polarizations. The passive structures of vertical waveguide bends, power splitters, and polarization splitters enable practical three dimensional integrated optics by providing vertical routing capability of the optical signal analogous to those typically found in conventional two dimensional waveguide interconnects. Three dimensionally integrated active devices such as low-loss hybrid modulators and vertically integrated modulator designs create fully functional

  8. Understanding Active and Passive Users: The Effects of an Active User Using Normal, Hard and Unreliable Technologies on User Assessment of Trust in Technology and Co-User

    PubMed Central

    Montague, Enid; JieXu

    2011-01-01

    The aim of this study was to understand how passive users perceive the trustworthiness of active users and technologies under varying technological conditions. An experimental study was designed to vary the functioning of technologies that active users interacted with, while passive users observed these interactions. Active and passive user ratings of technology and partner were collected. Exploratory data analysis suggests that passive users developed perceptions of technologies based on the functioning of the technology and how the active user interacted with the technologies. Findings from this research have implications for the design of technologies in environments where active and passive users interact with technologies in different ways. Future work in this area should explore interventions that lead to enhanced affective engagement and trust calibration. PMID:22192788

  9. Function of reactive oxygen species during animal development: passive or active?

    PubMed

    Covarrubias, Luis; Hernández-García, David; Schnabel, Denhí; Salas-Vidal, Enrique; Castro-Obregón, Susana

    2008-08-01

    Oxidative stress is considered causal of aging and pathological cell death, however, very little is known about its function in the natural processes that support the formation of an organism. It is generally thought that cells must continuously protect themselves from the possible damage caused by reactive oxygen species (ROS) (passive ROS function). However, presently, ROS are recognized as physiologically relevant molecules that mediate cell responses to a variety of stimuli, and the activities of several molecules, some developmentally relevant, are directly or indirectly regulated by oxidative stress (active ROS function). Here we review recent data that are suggestive of specific ROS functions during development of animals, particularly mammals.

  10. Evaluation of active and passive transport processes in corneas extracted from preserved rabbit eyes.

    PubMed

    Majumdar, Soumyajit; Hingorani, Tushar; Srirangam, Ramesh

    2010-04-01

    In vitro transcorneal permeability studies are an important screening tool in drug development. The objective of this research is to examine the feasibility of using corneas isolated from preserved rabbit eyes as a model for permeability evaluation. Eyes from male New Zealand White rabbits were used immediately or were stored overnight in phosphate-buffered saline (PBS) or Hanks balanced salt solution (HBSS) over wet ice. Integrity of isolated corneas was evaluated by measuring the TEER and by determining the permeability of paracellular and transcellular markers. Active transport was assessed by measuring transcorneal permeability of selected amino acids. Esterase activity was estimated using p-nitrophenyl assay. In all cases, corneas from freshly enucleated eyes were compared to those isolated from the day-old preserved eyes. Transcellular and paracellular passive diffusion was not affected by the storage medium and observed to be similar in the fresh and preserved eye models. However, amino acid transporters demonstrated lower functional activity in corneas excised from eyes preserved in PBS. Moreover, preserved eyes displayed almost 1.5-fold lower esterase activity in the corneal tissue. Thus, corneas isolated from day-old eyes, preserved in HBSS, closely mimics freshly excised rabbit corneas in terms of both active and passive transport characteristics but possesses slightly reduced enzymatic activity.

  11. Effect of lexical cues on the production of active and passive sentences in Broca's and Wernicke's aphasia

    PubMed Central

    Faroqi-Shah, Yasmeen; Thompson, Cynthia K.

    2011-01-01

    This study compared the sentence production abilities of individuals with Broca's and Wernicke's aphasia in an attempt to explore the extent to which impaired lexical retrieval impedes sentence production. The ability to produce active and passive reversible and non-reversible sentences was examined when varying amounts of lexical information was provided. The results showed that both Wernicke's and Broca's aphasic individuals were impaired in passive sentence production and that these difficulties were not overcome when lexical cues (the relevant nouns and uninflected verb) were provided. However when auxiliary and past tense morphemes were provided along with the verb stem, production of passive sentences improved drastically for both groups. Analysis of error patterns, however, revealed differences between the two groups, suggesting that Broca's aphasic subjects mayfind passive sentences difficult due to problems with retrieving the relevant grammatical morphemes. Subjects with Wernicke's aphasia may have been unable to automatically access the passive sentence structure. PMID:12744953

  12. Intercomparison and intercalibration of passive/active radon and active radon progeny instruments and methods in North America

    SciTech Connect

    George, A.C.; Tu, Keng W.

    1993-06-01

    An intercomparison and intercalibration exercise for radon and radon progeny measurements made with active and passive instruments was held at EML from October 22--30,1992. Twenty-five participants submitted 96 passive integrating devices, eight active devices for radon, and seven integrating devices for potential alpha energy concentration (PAEC). In addition, 40 grab samples for radon progeny analysis were taken by five groups that participated in person during the intercomparison. The results reported to EML indicate that the majority of the participants (70%) obtained mean results within 10% of the EML reference value. Although the instruments used in this exercise are based on different principles of collection and detection, they all appear reliable. However, in some instances there seemed to be some minor problems with quality control and calibration bias. Also, the large counting errors for the PAEC experienced by some of the participants can be minimized by using higher sampling air flow rates without sacrificing instrument portability.

  13. Passive/active microwave soil moisture retrieval disaggregation using SMAPVEX12 data

    NASA Astrophysics Data System (ADS)

    Fang, Bin; Lakshmi, Venkat

    2014-11-01

    SMAPVEX12 is a pre-launch field campaign for evaluating and testing the soil moisture retrievals retrieved from the SMAP project. During this experiment, airborne microwave observations from PALS radiometer and radar: brightness temperature and radar backscatter, as well as ground measurements were acquired. In this study, the remote sensing soil moisture was retrieved from SMAPVEX12 PALS radiometer L-band (6GHz) brightness temperature at high altitude flight. The PALS soil moisture was then aggregated and compared with PALS radar backscatter coefficient to generate high spatial resolution microwave soil moisture in change. The R2 values of PALS soil moisture retrieval validation range from 0.407-0.881, indicating good accuracy of soil moisture retrieval. The R2 values of comparison between aggregated PALS Δ and PALS Δ range from 0.492-0.805, while the downscaled Δ validation range from 0.128- 0.383.

  14. Detection of Rare Antimicrobial Resistance Profiles by Active and Passive Surveillance Approaches.

    PubMed

    Mather, Alison E; Reeve, Richard; Mellor, Dominic J; Matthews, Louise; Reid-Smith, Richard J; Dutil, Lucie; Haydon, Daniel T; Reid, Stuart W J

    2016-01-01

    Antimicrobial resistance (AMR) surveillance systems are generally not specifically designed to detect emerging resistances and usually focus primarily on resistance to individual drugs. Evaluating the diversity of resistance, using ecological metrics, allows the assessment of sampling protocols with regard to the detection of rare phenotypes, comprising combinations of resistances. Surveillance data of phenotypic AMR of Canadian poultry Salmonella Heidelberg and swine Salmonella Typhimurium var. 5- were used to contrast active (representative isolates derived from healthy animals) and passive (diagnostic isolates) surveillance and assess their suitability for detecting emerging resistance patterns. Although in both datasets the prevalences of resistance to individual antimicrobials were not significantly different between the two surveillance systems, analysis of the diversity of entire resistance phenotypes demonstrated that passive surveillance of diagnostic isolates detected more unique phenotypes. Whilst the most appropriate surveillance method will depend on the relevant objectives, under the conditions of this study, passive surveillance of diagnostic isolates was more effective for the detection of rare and therefore potentially emerging resistance phenotypes. PMID:27391966

  15. Detection of Rare Antimicrobial Resistance Profiles by Active and Passive Surveillance Approaches

    PubMed Central

    Mather, Alison E.; Reeve, Richard; Mellor, Dominic J.; Matthews, Louise; Reid-Smith, Richard J.; Haydon, Daniel T.; Reid, Stuart W. J.

    2016-01-01

    Antimicrobial resistance (AMR) surveillance systems are generally not specifically designed to detect emerging resistances and usually focus primarily on resistance to individual drugs. Evaluating the diversity of resistance, using ecological metrics, allows the assessment of sampling protocols with regard to the detection of rare phenotypes, comprising combinations of resistances. Surveillance data of phenotypic AMR of Canadian poultry Salmonella Heidelberg and swine Salmonella Typhimurium var. 5- were used to contrast active (representative isolates derived from healthy animals) and passive (diagnostic isolates) surveillance and assess their suitability for detecting emerging resistance patterns. Although in both datasets the prevalences of resistance to individual antimicrobials were not significantly different between the two surveillance systems, analysis of the diversity of entire resistance phenotypes demonstrated that passive surveillance of diagnostic isolates detected more unique phenotypes. Whilst the most appropriate surveillance method will depend on the relevant objectives, under the conditions of this study, passive surveillance of diagnostic isolates was more effective for the detection of rare and therefore potentially emerging resistance phenotypes. PMID:27391966

  16. Application of a passive/active autoparametric cantilever beam absorber with PZT actuator for Duffing systems

    NASA Astrophysics Data System (ADS)

    Silva-Navarro, G.; Abundis-Fong, H. F.; Vazquez-Gonzalez, B.

    2013-04-01

    An experimental investigation is carried out on a cantilever-type passive/active autoparametric vibration absorber, with a PZT patch actuator, to be used in a primary damped Duffing system. The primary system consists of a mass, viscous damping and a cubic stiffness provided by a soft helical spring, over which is mounted a cantilever beam with a PZT patch actuator actively controlled to attenuate harmonic and resonant excitation forces. With the PZT actuator on the cantilever beam absorber, cemented to the base of the beam, the auto-parametric vibration absorber is made active, thus enabling the possibility to control the effective stiffness and damping associated to the passive absorber and, as a consequence, the implementation of an active vibration control scheme able to preserve, as possible, the autoparametric interaction as well as to compensate varying excitation frequencies and parametric uncertainty. This active vibration absorber employs feedback information from a high resolution optical encoder on the primary Duffing system and an accelerometer on the tip beam absorber, a strain gage on the base of the beam, feedforward information from the excitation force and on-line computations from the nonlinear approximate frequency response, parameterized in terms of a proportional gain provided by a voltage input to the PZT actuator, thus modifying the closed-loop dynamic stiffness and providing a mechanism to asymptotically track an optimal, robust and stable attenuation solution on the primary Duffing system. Experimental results are included to describe the dynamic and robust performance of the overall closed-loop system.

  17. Active and passive computed tomography mixed waste focus area final report

    SciTech Connect

    Roberson, G P

    1998-08-19

    The Mixed Waste Focus Area (MWFA) Characterization Development Strategy delineates an approach to resolve technology deficiencies associated with the characterization of mixed wastes. The intent of this strategy is to ensure the availability of technologies to support the Department of Energy's (DOE) mixed waste low-level or transuranic (TRU) contaminated waste characterization management needs. To this end the MWFA has defined and coordinated characterization development programs to ensure that data and test results necessary to evaluate the utility of non-destructive assay technologies are available to meet site contact handled waste management schedules. Requirements used as technology development project benchmarks are based in the National TRU Program Quality Assurance Program Plan. These requirements include the ability to determine total bias and total measurement uncertainty. These parameters must be completely evaluated for waste types to be processed through a given nondestructive waste assay system constituting the foundation of activities undertaken in technology development projects. Once development and testing activities have been completed, Innovative Technology Summary Reports are generated to provide results and conclusions to support EM-30, -40, or -60 end user/customer technology selection. The Active and Passive Computed Tomography non-destructive assay system is one of the technologies selected for development by the MWFA. Lawrence Livermore National Laboratory's (LLNL) is developing the Active and Passive Computed Tomography (A&PCT) nondestructive assay (NDA) technology to identify and accurately quantify all detectable radioisotopes in closed containers of waste. This technology will be applicable to all types of waste regardless of .their classification; low level, transuranic or provide results and conclusions to support EM-30, -40, or -60 end user/customer technology selection. The Active and Passive Computed Tomography non

  18. X-Band Active-Passive Rf Pulse Compressor with Plasma Switches

    SciTech Connect

    Vikharev, A.L.; Ivanov, O.A.; Gorbachev, A.M.; Lobaev, M.A.; Isaev, V.A.; Tantawi, S.G.; Lewandowski, J.R.; Hirshfield, J.L.; /Omega-P, New Haven /Yale U.

    2012-04-27

    As proposed by SLAC, the efficiency of a pulse compressor of the SLED-II type could be increased by changing both the phase of the microwave source and the coupling coefficient of the delay line. In the existing SLED-II system at frequency 11.4 GHz, the resonant delay line is coupled with the source via an iris with a constant reflection coefficient. Replacement of the iris with an active component makes it possible to create an active SLED-II system. In this paper, the use of plasma switches as the active elements is discussed. Plasma switches have been developed and tested at a high-power level for production of flattop compressed pulses. Active switching of SLED-II has demonstrated a marked increase in efficiency (by 20%) and power gain (by 37%) as compared with passive switching. The active compressor has produced 173 ns rf flattop output pulses with a power of about 112 MW.

  19. Use of Radar Vegetation Index (RVI) in Passive Microwave Algorithms for Soil Moisture Estimates

    NASA Astrophysics Data System (ADS)

    Rowlandson, T. L.; Berg, A. A.

    2013-12-01

    The Soil Moisture Active Passive (SMAP) satellite will provide a unique opportunity for the estimation of soil moisture by having simultaneous radar and radiometer measurements available. As with the Soil Moisture and Ocean Salinity (SMOS) satellite, the soil moisture algorithms will need to account for the contribution of vegetation to the brightness temperature. Global maps of vegetation volumetric water content (VWC) are difficult to obtain, and the SMOS mission has opted to estimate the optical depth of standing vegetation by using a relationship between the VWC and the leaf area index (LAI). LAI is estimated from optical remote sensing or through soil-vegetation-atmosphere transfer modeling. During the growing season, the VWC of agricultural crops can increase rapidly, and if cloud cover exists during an optical acquisition, the estimation of LAI may be delayed, resulting in an underestimation of the VWC and overestimation of the soil moisture. Alternatively, the radar vegetation index (RVI) has shown strong correlation and linear relationship with VWC for rice and soybeans. Using the SMAP radar to produce RVI values that are coincident to brightness temperature measurements may eliminate the need for LAI estimates. The SMAP Validation Experiment 2012 (SMAPVEX12) was a cal/val campaign for the SMAP mission held in Manitoba, Canada, during a 6-week period in June and July, 2012. During this campaign, soil moisture measurements were obtained for 55 fields with varying soil texture and vegetation cover. Vegetation was sampled from each field weekly to determine the VWC. Soil moisture measurements were taken coincident to overpasses by an aircraft carrying the Passive and Active L-band System (PALS) instrumentation. The aircraft flew flight lines at both high and low altitudes. The low altitude flight lines provided a footprint size approximately equivalent to the size of the SMAPVEX12 field sites. Of the 55 field sites, the low altitude flight lines provided

  20. Integrated active and passive control design methodology for the LaRC CSI evolutionary model

    NASA Technical Reports Server (NTRS)

    Voth, Christopher T.; Richards, Kenneth E., Jr.; Schmitz, Eric; Gehling, Russel N.; Morgenthaler, Daniel R.

    1994-01-01

    A general design methodology to integrate active control with passive damping was demonstrated on the NASA LaRC CSI Evolutionary Model (CEM), a ground testbed for future large, flexible spacecraft. Vibration suppression controllers designed for Line-of Sight (LOS) minimization were successfully implemented on the CEM. A frequency-shaped H2 methodology was developed, allowing the designer to specify the roll-off of the MIMO compensator. A closed loop bandwidth of 4 Hz, including the six rigid body modes and the first three dominant elastic modes of the CEM was achieved. Good agreement was demonstrated between experimental data and analytical predictions for the closed loop frequency response and random tests. Using the Modal Strain Energy (MSE) method, a passive damping treatment consisting of 60 viscoelastically damped struts was designed, fabricated and implemented on the CEM. Damping levels for the targeted modes were more than an order of magnitude larger than for the undamped structure. Using measured loss and stiffness data for the individual damped struts, analytical predictions of the damping levels were very close to the experimental values in the (1-10) Hz frequency range where the open loop model matched the experimental data. An integrated active/passive controller was successfully implemented on the CEM and was evaluated against an active-only controller. A two-fold increase in the effective control bandwidth and further reductions of 30 percent to 50 percent in the LOS RMS outputs were achieved compared to an active-only controller. Superior performance was also obtained compared to a High-Authority/Low-Authority (HAC/LAC) controller.

  1. Telencephalic neural activation following passive avoidance learning in a terrestrial toad.

    PubMed

    Puddington, Martín M; Daneri, M Florencia; Papini, Mauricio R; Muzio, Rubén N

    2016-12-15

    The present study explores passive avoidance learning and its neural basis in toads (Rhinella arenarum). In Experiment 1, two groups of toads learned to move from a lighted compartment into a dark compartment. After responding, animals in the experimental condition were exposed to an 800-mM strongly hypertonic NaCl solution that leads to weight loss. Control animals received exposure to a 300-mM slightly hypertonic NaCl solution that leads to neither weight gain nor loss. After 10 daily acquisition trials, animals in the experimental group showed significantly longer latency to enter the dark compartment. Additionally, 10 daily trials in which both groups received the 300-mM NaCl solution after responding eliminated this group effect. Thus, experimental animals showed gradual acquisition and extinction of a passive avoidance respond. Experiment 2 replicated the gradual acquisition effect, but, after the last trial, animals were sacrificed and neural activation was assessed in five brain regions using AgNOR staining for nucleoli-an index of brain activity. Higher activation in the experimental animals, relative to controls, was observed in the amygdala and striatum. Group differences in two other regions, lateral pallium and septum, were borderline, but nonsignificant, whereas group differences in the medial pallium were nonsignificant. These preliminary results suggest that a striatal-amygdala activation could be a key component of the brain circuit controlling passive avoidance learning in amphibians. The results are discussed in relation to the results of analogous experiments with other vertebrates. PMID:27498147

  2. Multimodal integration of self-motion cues in the vestibular system: active versus passive translations.

    PubMed

    Carriot, Jerome; Brooks, Jessica X; Cullen, Kathleen E

    2013-12-11

    The ability to keep track of where we are going as we navigate through our environment requires knowledge of our ongoing location and orientation. In response to passively applied motion, the otolith organs of the vestibular system encode changes in the velocity and direction of linear self-motion (i.e., heading). When self-motion is voluntarily generated, proprioceptive and motor efference copy information is also available to contribute to the brain's internal representation of current heading direction and speed. However to date, how the brain integrates these extra-vestibular cues with otolith signals during active linear self-motion remains unknown. Here, to address this question, we compared the responses of macaque vestibular neurons during active and passive translations. Single-unit recordings were made from a subgroup of neurons at the first central stage of sensory processing in the vestibular pathways involved in postural control and the computation of self-motion perception. Neurons responded far less robustly to otolith stimulation during self-generated than passive head translations. Yet, the mechanism underlying the marked cancellation of otolith signals did not affect other characteristics of neuronal responses (i.e., baseline firing rate, tuning ratio, orientation of maximal sensitivity vector). Transiently applied perturbations during active motion further established that an otolith cancellation signal was only gated in conditions where proprioceptive sensory feedback matched the motor-based expectation. Together our results have important implications for understanding the brain's ability to ensure accurate postural and motor control, as well as perceptual stability, during active self-motion.

  3. Biological effects of passive versus active scanning proton beams on human lung epithelial cells.

    PubMed

    Gridley, Daila S; Pecaut, Michael J; Mao, Xiao W; Wroe, Andrew J; Luo-Owen, Xian

    2015-02-01

    The goal was to characterize differences in cell response after exposure to active beam scanning (ABS) protons compared to a passive delivery system. Human lung epithelial (HLE) cells were evaluated at various locations along the proton depth dose profile. The dose delivered at the Bragg peak position was essentially identical (∼4 Gy) with the two techniques, but depth dose data showed that ABS resulted in lower doses at entry and more rapid drop-off after the peak. Average dose rates for the passive and ABS beams were 1.1 Gy/min and 5.1 Gy/min, respectively; instantaneous dose rates were 19.2 Gy/min and 2,300 Gy/min (to a 0.5 × 0.5 mm(2) voxel). Analysis of DNA synthesis was based on (3)H-TdR incorporation. Quantitative real-time polymerase chain reaction (RT-PCR) was done to determine expression of genes related to p53 signaling and DNA damage; a total of 152 genes were assessed. Spectral karyotyping and analyses of the Golgi apparatus and cytokines produced by the HLE cells were also performed. At or near the Bragg peak position, ABS protons resulted in a greater decrease in DNA synthesis compared to passively delivered protons. Genes with >2-fold change (P < 0.05 vs. 0 Gy) after passive proton irradiation at one or more locations within the Bragg curve were BTG2, CDKN1A, IFNB1 and SIAH1. In contrast, many more genes had >2-fold difference with ABS protons: BRCA1, BRCA2, CDC25A, CDC25C, CCNB2, CDK1, DMC1, DNMT1, E2F1, EXO1, FEN1, GADD45A, GTSE1, IL-6, JUN, KRAS, MDM4, PRC1, PTTG1, RAD51, RPA1, TNF, WT1, XRCC2, XRCC3 and XRCC6BP1. Spectral karyotyping revealed numerous differences in chromosomal abnormalities between the two delivery systems, especially at or near the Bragg peak. Percentage of cells staining for the Golgi apparatus was low after exposure to passive and active proton beams. Studies such as this are needed to ensure patient safety and make modifications in ABS delivery, if necessary.

  4. Synergism of active and passive microwave data for estimating bare surface soil moisture

    NASA Technical Reports Server (NTRS)

    Saatchi, Sasan S.; Njoku, Eni G.; Wegmueller, Urs

    1993-01-01

    Active and passive microwave sensors were applied effectively to the problem of estimating the surface soil moisture in a variety of environmental conditions. Research to date has shown that both types of sensors are also sensitive to the surface roughness and the vegetation cover. In estimating the soil moisture, the effect of the vegetation and roughness are often corrected either by acquiring multi-configuration (frequency and polarization) data or by adjusting the surface parameters in order to match the model predictions to the measured data. Due to the limitations on multi-configuration spaceborne data and the lack of a priori knowledge of the surface characteristics for parameter adjustments, it was suggested that the synergistic use of the sensors may improve the estimation of the soil moisture over the extreme range of naturally occurring soil and vegetation conditions. To investigate this problem, the backscattering and emission from a bare soil surface using the classical rough surface scattering theory were modeled. The model combines the small perturbation and the Kirchhoff approximations in conjunction with the Peak formulation to cover a wide range of surface roughness parameters with respect to frequency for both active and passive measurements. In this approach, the same analytical method was used to calculate the backscattering and emissivity. Therefore, the active and passive simulations can be combined at various polarizations and frequencies in order to estimate the soil moisture more actively. As a result, it is shown that (1) the emissivity is less dependent on the surface correlation length, (2) the ratio of the backscattering coefficient (HH) over the surface reflectivity (H) is almost independent of the soil moisture for a wide range of surface roughness, and (3) this ratio can be approximated as a linear function of the surface rms height. The results were compared with the data obtained by a multi-frequency radiometer

  5. Active Immunity Induced by Passive IgG Post-Exposure Protection against Ricin

    PubMed Central

    Hu, Charles Chen; Yin, Junfei; Chau, Damon; Cherwonogrodzky, John W.; Hu, Wei-Gang

    2014-01-01

    Therapeutic antibodies can confer an instant protection against biothreat agents when administered. In this study, intact IgG and F(ab’)2 from goat anti-ricin hyperimmune sera were compared for the protection against lethal ricin mediated intoxication. Similar ricin-binding affinities and neutralizing activities in vitro were observed between IgG and F(ab’)2 when compared at the same molar concentration. In a murine ricin intoxication model, both IgG and F(ab’)2 could rescue 100% of the mice by one dose (3 nmol) administration of antibodies 1 hour after 5 × LD50 ricin challenge. Nine days later, when the rescued mice received a second ricin challenge (5 × LD50), only the IgG-treated mice survived; the F(ab’)2-treated mice did not. The experimental design excluded the possibility of residual goat IgG responsible for the protection against the second ricin challenge. Results confirmed that the active immunity against ricin in mice was induced quickly following the passive delivery of a single dose of goat IgG post-exposure. Furthermore, it was demonstrated that the induced active immunity against ricin in mice lasted at least 5 months. Therefore, passive IgG therapy not only provides immediate protection to the victim after ricin exposure, but also elicits an active immunity against ricin that subsequently results in long term protection. PMID:24451844

  6. Speech recognition in noise with active and passive hearing protectors: a comparative study.

    PubMed

    Bockstael, Annelies; De Coensel, Bert; Botteldooren, Dick; D'Haenens, Wendy; Keppler, Hannah; Maes, Leen; Philips, Birgit; Swinnen, Freya; Bart, Vinck

    2011-06-01

    The perceived negative influence of standard hearing protectors on communication is a common argument for not wearing them. Thus, "augmented" protectors have been developed to improve speech intelligibility. Nevertheless, their actual benefit remains a point of concern. In this paper, speech perception with active earplugs is compared to standard passive custom-made earplugs. The two types of active protectors included amplify the incoming sound with a fixed level or to a user selected fraction of the maximum safe level. For the latter type, minimal and maximal amplification are selected. To compare speech intelligibility, 20 different speech-in-noise fragments are presented to 60 normal-hearing subjects and speech recognition is scored. The background noise is selected from realistic industrial noise samples with different intensity, frequency, and temporal characteristics. Statistical analyses suggest that the protectors' performance strongly depends on the noise condition. The active protectors with minimal amplification outclass the others for the most difficult and the easiest situations, but they also limit binaural listening. In other conditions, the passive protectors clearly surpass their active counterparts. Subsequently, test fragments are analyzed acoustically to clarify the results. This provides useful information for developing prototypes, but also indicates that tests with human subjects remain essential. PMID:21682395

  7. Retrieval of Precipitation Profiles from Multiresolution, Multifrequency, Active and Passive Microwave Observations

    NASA Technical Reports Server (NTRS)

    Grecu, Mircea; Anagnostou, Emmanouil N.; Olson, William S.; Starr, David OC. (Technical Monitor)

    2002-01-01

    In this study, a technique for estimating vertical profiles of precipitation from multifrequency, multiresolution active and passive microwave observations is investigated using both simulated and airborne data. The technique is applicable to the Tropical Rainfall Measuring Mission (TRMM) satellite multi-frequency active and passive observations. These observations are characterized by various spatial and sampling resolutions. This makes the retrieval problem mathematically more difficult and ill-determined because the quality of information decreases with decreasing resolution. A model that, given reflectivity profiles and a small set of parameters (including the cloud water content, the intercept drop size distribution, and a variable describing the frozen hydrometeor properties), simulates high-resolution brightness temperatures is used. The high-resolution simulated brightness temperatures are convolved at the real sensor resolution. An optimal estimation procedure is used to minimize the differences between simulated and observed brightness temperatures. The retrieval technique is investigated using cloud model synthetic and airborne data from the Fourth Convection And Moisture Experiment. Simulated high-resolution brightness temperatures and reflectivities and airborne observation strong are convolved at the resolution of the TRMM instruments and retrievals are performed and analyzed relative to the reference data used in observations synthesis. An illustration of the possible use of the technique in satellite rainfall estimation is presented through an application to TRMM data. The study suggests improvements in combined active and passive retrievals even when the instruments resolutions are significantly different. Future work needs to better quantify the retrievals performance, especially in connection with satellite applications, and the uncertainty of the models used in retrieval.

  8. Integration of Active and Passive Safety Technologies--A Method to Study and Estimate Field Capability.

    PubMed

    Hu, Jingwen; Flannagan, Carol A; Bao, Shan; McCoy, Robert W; Siasoco, Kevin M; Barbat, Saeed

    2015-11-01

    The objective of this study is to develop a method that uses a combination of field data analysis, naturalistic driving data analysis, and computational simulations to explore the potential injury reduction capabilities of integrating passive and active safety systems in frontal impact conditions. For the purposes of this study, the active safety system is actually a driver assist (DA) feature that has the potential to reduce delta-V prior to a crash, in frontal or other crash scenarios. A field data analysis was first conducted to estimate the delta-V distribution change based on an assumption of 20% crash avoidance resulting from a pre-crash braking DA feature. Analysis of changes in driver head location during 470 hard braking events in a naturalistic driving study found that drivers' head positions were mostly in the center position before the braking onset, while the percentage of time drivers leaning forward or backward increased significantly after the braking onset. Parametric studies with a total of 4800 MADYMO simulations showed that both delta-V and occupant pre-crash posture had pronounced effects on occupant injury risks and on the optimal restraint designs. By combining the results for the delta-V and head position distribution changes, a weighted average of injury risk reduction of 17% and 48% was predicted by the 50th percentile Anthropomorphic Test Device (ATD) model and human body model, respectively, with the assumption that the restraint system can adapt to the specific delta-V and pre-crash posture. This study demonstrated the potential for further reducing occupant injury risk in frontal crashes by the integration of a passive safety system with a DA feature. Future analyses considering more vehicle models, various crash conditions, and variations of occupant characteristics, such as age, gender, weight, and height, are necessary to further investigate the potential capability of integrating passive and DA or active safety systems. PMID

  9. Passive and active microrheology for cross-linked F-actin networks in vitro.

    PubMed

    Lee, Hyungsuk; Ferrer, Jorge M; Nakamura, Fumihiko; Lang, Matthew J; Kamm, Roger D

    2010-04-01

    Actin filament (F-actin) is one of the dominant structural constituents in the cytoskeleton. Orchestrated by various actin-binding proteins (ABPs), F-actin is assembled into higher-order structures such as bundles and networks that provide mechanical support for the cell and play important roles in numerous cellular processes. Although mechanical properties of F-actin networks have been extensively studied, the underlying mechanisms for network elasticity are not fully understood, in part because different measurements probe different length and force scales. Here, we developed both passive and active microrheology techniques using optical tweezers to estimate the mechanical properties of F-actin networks at a length scale comparable to cells. For the passive approach we tracked the motion of a thermally fluctuating colloidal sphere to estimate the frequency-dependent complex shear modulus of the network. In the active approach, we used an optical trap to oscillate an embedded microsphere and monitored the response in order to obtain network viscoelasticity over a physiologically relevant force range. While both active and passive measurements exhibit similar results at low strain, the F-actin network subject to high strain exhibits non-linear behavior which is analogous to the strain-hardening observed in macroscale measurements. Using confocal and total internal reflection fluorescent microscopy, we also characterize the microstructure of reconstituted F-actin networks in terms of filament length, mesh size and degree of bundling. Finally, we propose a model of network connectivity by investigating the effect of filament length on the mechanical properties and structure. PMID:19883801

  10. Passive and Active Fast-Neutron Imaging in Support of Advanced Fuel Cycle Initiative Safeguards Campaign

    SciTech Connect

    Blackston, Matthew A; Hausladen, Paul

    2010-04-01

    Results from safeguards-related passive and active coded-aperture fast-neutron imaging measurements of plutonium and highly enriched uranium (HEU) material configurations performed at Idaho National Laboratory s Zero Power Physics Reactor facility are presented. The imaging measurements indicate that it is feasible to use fast neutron imaging in a variety of safeguards-related tasks, such as monitoring storage, evaluating holdup deposits in situ, or identifying individual leached hulls still containing fuel. The present work also presents the first demonstration of imaging of differential die away fast neutrons.

  11. Synergistic use of active and passive microwave in soil moisture estimation

    NASA Technical Reports Server (NTRS)

    O'Neill, P.; Chauhan, N.; Jackson, T.; Saatchi, S.

    1992-01-01

    Data gathered during the MACHYDRO experiment in central Pennsylvania in July 1990 have been utilized to study the synergistic use of active and passive microwave systems for estimating soil moisture. These data sets were obtained during an eleven-day period with NASA's Airborne Synthetic Aperture Radar (AIRSAR) and Push-Broom Microwave Radiometer (PBMR) over an instrumented watershed which included agricultural fields with a number of different crop covers. Simultaneous ground truth measurements were also made in order to characterize the state of vegetation and soil moisture under a variety of meteorological conditions. A combination algorithm is presented as applied to a representative corn field in the MACHYDRO watershed.

  12. A Large-N Mixed Sensor Active + Passive Seismic Array near Sweetwater, TX

    NASA Astrophysics Data System (ADS)

    Barklage, M.; Hollis, D.; Gridley, J. M.; Woodward, R.; Spriggs, N.

    2014-12-01

    A collaborative high-density seismic survey using broadband and short period seismic sensors was conducted March 7 - April 30, 2014 near Sweetwater, TX. The objective of the survey was to use a combination of controlled source shot slices and passive seismic recordings recorded by multiple types of sensors with different bandwidths and sensitivities to image the subsurface. The broadband component of the survey consisted of 25 continuously recording seismic stations comprised of 20 Trillium Compact Posthole sensors from Nanometrics and 5 Polar Trillium 120PHQs from the IRIS/PASSCAL Instrument Center (PIC). The broadband stations also utilized 25 Centaur digitizers from Nanometrics as well as 25 polar quick deploy enclosures from the PIC. The broadband array was designed to maximize horizontal traveling seismic energy for surface wave analysis over the primary target area with sufficient offset for imaging objectives at depth. The short period component of the survey consisted of 2639 receiver locations using Zland nodes from NodalSeismic. The nodes are further divided into 3 sub-arrays: 1) outlier array 2) active source array 3) backbone array. The outlier array consisted of 25 continuously recording nodes distributed around the edge of the survey at a distance of ~5 km from the survey boundary, and provided valuable constraints to passive data analysis techniques at the edge of the survey boundary. The active source patch consisted of densely spaced nodes that were designed to record signals from a Vibroseis source truck for active source reflection processing and imaging. The backbone array consisted of 292 nodes that covered the entirety of the survey area to maximize the value of the passive data analysis. By utilizing continuous recording and smartly designed arrays for measuring local and regional earthquakes we can incorporate velocity information derived from passive data analysis into the active source processing workflow to produce a superior subsurface

  13. Active and passive calcium transport systems in plant cells: Progress report, January 1986--June 1989

    SciTech Connect

    Sze, H.

    1989-01-01

    The objectives of this proposal are to identify and characterize active (energy-dependent) and passive calcium transport systems that work together to regulate calcium levels in the cytoplasm of plant cells. Several different energy-dependent Ca transport systems have been identified and characterized from oat root tissue (a monocot tissue) and carrot suspension cells (a dicot tissue). They are described in more detail below. I also have included in this progress report our continuing studies to understand the mode of action of the Helminthosporium maydis T toxin. This study was initially supported by a preceding DOE grant. The time needed to complete the study overlapped partly with the present grant period.

  14. Capability and limitation study of the DDT passive-active neutron waste assay instrument

    SciTech Connect

    Nicholas, N.J.; Coop, K.L.; Estep, R.J.

    1992-05-01

    The differential-dieaway-technique passive-active neutron assay system is widely used by transuranic waste generators to certify their drummed waste for eventual shipment to the Waste Isolation Pilot Plant (WIPP). Stricter criteria being established for waste emplacement at the WIPP site has led to a renewed interest in improvements to and a better understanding of current nondestructive assay (NDA) techniques. Our study includes the effects of source position, extreme matrices, high neutron backgrounds, and source self-shielding to explore the system`s capabilities and limitations and to establish a basis for comparison with other NDA systems. 11 refs.

  15. Capability and limitation study of the DDT passive-active neutron waste assay instrument

    SciTech Connect

    Nicholas, N.J.; Coop, K.L.; Estep, R.J.

    1992-05-01

    The differential-dieaway-technique passive-active neutron assay system is widely used by transuranic waste generators to certify their drummed waste for eventual shipment to the Waste Isolation Pilot Plant (WIPP). Stricter criteria being established for waste emplacement at the WIPP site has led to a renewed interest in improvements to and a better understanding of current nondestructive assay (NDA) techniques. Our study includes the effects of source position, extreme matrices, high neutron backgrounds, and source self-shielding to explore the system's capabilities and limitations and to establish a basis for comparison with other NDA systems. 11 refs.

  16. Active and passive compensation of APPLE II-introduced multipole errors through beam-based measurement

    NASA Astrophysics Data System (ADS)

    Chung, Ting-Yi; Huang, Szu-Jung; Fu, Huang-Wen; Chang, Ho-Ping; Chang, Cheng-Hsiang; Hwang, Ching-Shiang

    2016-08-01

    The effect of an APPLE II-type elliptically polarized undulator (EPU) on the beam dynamics were investigated using active and passive methods. To reduce the tune shift and improve the injection efficiency, dynamic multipole errors were compensated using L-shaped iron shims, which resulted in stable top-up operation for a minimum gap. The skew quadrupole error was compensated using a multipole corrector, which was located downstream of the EPU for minimizing betatron coupling, and it ensured the enhancement of the synchrotron radiation brightness. The investigation methods, a numerical simulation algorithm, a multipole error correction method, and the beam-based measurement results are discussed.

  17. Performance of an active/passive hybrid solar system utilizing vapor transport

    SciTech Connect

    Hedstrom, J.C.

    1984-01-01

    Vapor-phase heat-transport systems are being tested in two of the passive test cells at Los Alamos. The systems consist of an active fin-and-tube collector and a condenser inside a water storage tank. The refrigerant, R-11, can be returned to the collector with a pump or with a self-pumping scheme. A computer model was developed to predict the behavior of the system, after which the computer was used to predict the annual performance of these systems in five cities. The report compares the measured and the predicted results as well as the system's sensitivity to several parameters.

  18. Cat vestibular neurons that exhibit different responses to active and passive yaw head rotations

    NASA Technical Reports Server (NTRS)

    Robinson, F. R.; Tomko, D. L.

    1987-01-01

    Neurons in the vestibular nuclei were recorded in alert cats during voluntary yaw rotations of the head and during the same rotations delivered with a turntable driven from a record of previous voluntary movements. During both voluntary and passive rotations, 35 percent (6/17) of neurons tested responded at higher rates or for a larger part of the movement during voluntary movements than during the same rotations delivered with the turntable. Neck sensory input was evaluated separately in many of these cells and can account qualitatively for the extra firing present during active movement.

  19. Cost-effective and monitoring-active technique for TDM-passive optical networks

    NASA Astrophysics Data System (ADS)

    Chi, Chang-Chia; Lin, Hong-Mao; Tarn, Chen-Wen; Lin, Huang-Liang

    2014-08-01

    A reliable, detection-active and cost-effective method which employs the hello and heartbeat signals for branched node distinguishing to monitor fiber fault in any branch of distribution fibers of a time division multiplexing passive optical network (TDM-PON) is proposed. With this method, the material cost of building an optical network monitor system for a TDM-PON with 168 ONUs and the time of identifying a multiple branch faults is significantly reduced in a TDM-PON system of any scale. A fault location in a 1 × 32 TDM-PON system using this method to identify the fault branch is demonstrated.

  20. Microwave remote sensing: Active and passive. Volume 1 - Microwave remote sensing fundamentals and radiometry

    NASA Technical Reports Server (NTRS)

    Ulaby, F. T.; Moore, R. K.; Fung, A. K.

    1981-01-01

    The three components of microwave remote sensing (sensor-scene interaction, sensor design, and measurement techniques), and the applications to geoscience are examined. The history of active and passive microwave sensing is reviewed, along with fundamental principles of electromagnetic wave propagation, antennas, and microwave interaction with atmospheric constituents. Radiometric concepts are reviewed, particularly for measurement problems for atmospheric and terrestrial sources of natural radiation. Particular attention is given to the emission by atmospheric gases, clouds, and rain as described by the radiative transfer function. Finally, the operation and performance characteristics of radiometer receivers are discussed, particularly for measurement precision, calibration techniques, and imaging considerations.

  1. Active and Passive Application of the Phosphoric Acid on the Bond Strength of Lithium Disilicate.

    PubMed

    Giraldo, Tatiana Cardona; Villada, Vanessa Roldan; Castillo, Mauricio Peña; Gomes, Osnara Maria Mongruel; Bittencourt, Bruna Fortes; Dominguez, John Alexis

    2016-01-01

    The objective of this study was to evaluate the effect of passive or active phosphoric acid (PA) application after hydrofluoric acid (HA) treatment on the microshear bond strength of lithium disilicate. Thirty ceramic discs were made with IPS Emax 2 (10 mm thick and 10 mm diameter). The specimens were divided into 3 groups, A: 9.6% HA application; AF: 9.6% HA application + cleaning with 37% PA in passive mode and AFF: 9.6% HA application + cleaning with 37% PA in active mode. For the microshear test, four tygons (0.9 mm diameter and 0.2 mm high) were filled with resin cement (RelyX Ultimate) and placed on the ceramic disks. After testing, the fracture modes were examined under scanning electron microscopy. Data were analyzed by one-way ANOVA and Tukey's post test (α=0.05). The bond strength values were significantly higher in Group AFF (11.0±2.5 MPa) compared with group A (8.1±2.6 MPa) (p<0.002). AF group was not statistically different (9.4±2.5 MPa) from Group A. It was concluded that the active application of 37% PA after 9.6% HA increases the microshear bond strength values between the resin cement and lithium disilicate ceramic.

  2. The influence of yaw motion on the perception of active vs passive visual curvilinear displacement.

    PubMed

    Savona, Florian; Stratulat, Anca Melania; Roussarie, Vincent; Bourdin, Christophe

    2015-01-01

    Self-motion perception, which partly determines the realism of dynamic driving simulators, is based on multisensory integration. However, it remains unclear how the brain integrates these cues to create adequate motion perception, especially for curvilinear displacements. In the present study, the effect of visual, inertial and visuo-inertial cues (concordant or discordant bimodal cues) on self-motion perception was analyzed. Subjects were asked to evaluate (externally produced) or produce (self-controlled) curvilinear displacements as accurately as possible. The results show systematic overestimation of displacement, with better performance for active subjects than for passive ones. Furthermore, it was demonstrated that participants used unimodal or bimodal cues differently in performing their activity. When passive, subjects systematically integrated visual and inertial cues even when discordant, but with weightings that depended on the dynamics. On the contrary, active subjects were able to reject the inertial cue when the discordance became too high, producing self-motion perception on the basis of more reliable information. Thereby, multisensory integration seems to follow a non-linear integration model of, i.e., the cues' weight changes with the cue reliability and/or the intensity of the stimuli, as reported by previous studies. These results represent a basis for the adaptation of motion cueing algorithms are developed for dynamic driving simulators, by taking into account the dynamics of simulated motion in line with the status of the participants (driver or passenger).

  3. Women and lung cancer: a comparison of active and passive smokers with nonexposed nonsmokers.

    PubMed

    Miller, G H; Golish, J A; Cox, C E; Chacko, D C

    1994-01-01

    Prior to the 1920s, lung cancer was a rare disease. However, the current increase in lung cancer appears to parallel the increase in smoking for both men and women with a 30- to 50-year delay. National lung cancer deaths continue to rise, with over 168,000 total deaths estimated in 1992. Women are now showing higher percentage increases in lung cancer than men from active smoking. The data from the Erie County Study on Smoking and Health (ECSSH), a population study, were used to measure the effects of both active and passive smoking on women's lung cancer mortality. The three major categories of exposure (no known or minimal exposure, passive smoking exposed, and active smoking) were used in the analyses. The results from the population data in Erie County, PA, were based on 528 nonexposed nonsmoking women, 3138 exposed nonsmoking women, and 1747 smoking women. Deaths due to lung cancer as a percentage of total deaths excluding traumatic deaths were 0.2% for the nonexposed nonsmoking women, 0.9% for the exposed nonsmoking women, and 8.0% for women who smoked. The data showed that women smokers died of lung cancer at a rate 9 times greater than exposed nonsmokers and 42 times greater than nonexposed nonsmokers.

  4. Attenuation Properties of Fontainebleau Sandstone During True-Triaxial Deformation using Active and Passive Ultrasonics

    NASA Astrophysics Data System (ADS)

    Goodfellow, S. D.; Tisato, N.; Ghofranitabari, M.; Nasseri, M. H. B.; Young, R. P.

    2015-11-01

    Active and passive ultrasonic methods were used to study the evolution of attenuation properties in a sample of Fontainebleau sandstone during true-triaxial deformation. A cubic sample of Fontainebleau sandstone (80 mm × 80 mm × 80 mm) was deformed under true-triaxial stresses until failure. From the stress state: σ _3 = 5 MPa and σ _1 = σ _2 = 35 MPa, σ _1 was increased at a constant displacement rate until the specimen failed. Acoustic emission (AE) activity was monitored by 18 piezoelectric sensors and bandpass filtered between 100 kHz and 1 MHz. A source location analysis was performed on discrete AE data harvested from the continuous record where 48,502 events were locatable inside the sample volume. AE sensors were sequentially pulsed during periodic P-wave surveys among 135 raypaths. Analytical solutions for Biot, squirt flow, viscous shear, and scattering attenuation were used to discuss to observed attenuation at various stages of the experiment. We concluded that initial attenuation anisotropy was stress induced and resulted from friction and squirt flow. Later attenuation of the high-frequency spectrum was attributed to scattering as a result of the formation of large macroscopic vertical fractures. Passive (AE) ultrasonic data produced similar information to that from active data but with enhanced temporal and spacial resolution.

  5. Ethanol effects on active and passive Na+ flux in toad bladder.

    PubMed

    Amaranath, L; Anton, A H

    1977-11-01

    Ethanol, like other anesthetics, has been reported to interfere with active Na+ transport in living membranes. In an attempt to elucidate the mechanism by which ethanol exerts this action, we tested in the toad bladder membrane: 1) the effect of ethanol on active Na+ transport, 2) the interaction of ethanol with vasopressin on Na+ transport, and 3) the effect of ethanol on passive Na+ flux. We found that, a) 1-500 microgram/ml of ethanol stimulated, and 10,000 microgram/ml depressed active Na+ transport; b) the combined effect of stimulating concentrations of ethanol and vasopressin, although suggestive of a positive interaction, might have arisen by chance (p = 0.08); c) depressant concentrations of ethanol failed to suppress the stimulation by vasopressin; and d) passive Na+ flux in bladders treated with ouabain and ethacrynic acid was not affected by ethanol (1-100 microgram/ml). These results indicate that ethanol in concentrations ranging from 1 to 10,000 microgram/ml does not block ATP/ATPase Na+ pump but apparently exerts a dose-dependent, stimulant-depressant effect on Na+ channels in the membrane.

  6. Comparison of metabolic and biomechanic responses to active vs. passive warm-up procedures before physical exercise.

    PubMed

    Brunner-Ziegler, Sophie; Strasser, Barbara; Haber, Paul

    2011-04-01

    Active warm-up before physical exercise is a widely accepted practice to enhance physical performance, whereas data on modalities to passively raise tissue temperature are rare. The study compared the effect of active vs. passive warm-up procedures before exercise on energy supply and muscle strength performance. Twenty young, male volunteers performed 3 spiroergometer-test series without prior warm-up and after either an active or passive warm-up procedure. Oxygen uptake (VO2), heart rate (HR), pH value, and lactate were determined at 80% of individual VO2max values and during recovery. Comparing no prior warm-up with passive warm-up, pH values were lower at the fourth test minute (p < 0.004), and lactate values were higher at the sixth and third minutes of recovery (p < 0.01 and p < 0.010, respectively), after no prior warm-up. Comparing active with passive warm-up, HR was lower, and VO2 values were higher at the fourth and sixth test minutes (p < 0.033 and p < 0.011, respectively, and p < 0.015 and p < 0.022, respectively) after active warm-up. Differentiation between active and passive warm-up was more pronounced than between either warm-up or no warm-up. Conditions that may promote improved performance were more present after active vs. passive warm-up. Thus, athletes may reach the metabolic steady state faster after active warm-up. PMID:20733525

  7. Predictive Optimal Control of Active and Passive Building Thermal Storage Inventory

    SciTech Connect

    Gregor P. Henze; Moncef Krarti

    2003-12-17

    Cooling of commercial buildings contributes significantly to the peak demand placed on an electrical utility grid. Time-of-use electricity rates encourage shifting of electrical loads to off-peak periods at night and weekends. Buildings can respond to these pricing signals by shifting cooling-related thermal loads either by precooling the building's massive structure or the use of active thermal energy storage systems such as ice storage. While these two thermal batteries have been engaged separately in the past, this project investigates the merits of harnessing both storage media concurrently in the context of predictive optimal control. This topical report describes the demonstration of the model-based predictive optimal control for active and passive building thermal storage inventory in a test facility in real-time using time-of-use differentiated electricity prices without demand charges. The laboratory testing findings presented in this topical report cover the second of three project phases. The novel supervisory controller successfully executed a three-step procedure consisting of (1) short-term weather prediction, (2) optimization of control strategy over the next planning horizon using a calibrated building model, and (3) post-processing of the optimal strategy to yield a control command for the current time step that can be executed in the test facility. The primary and secondary building mechanical systems were effectively orchestrated by the model-based predictive optimal controller in real-time while observing comfort and operational constraints. The findings reveal that when the optimal controller is given imperfect weather fore-casts and when the building model used for planning control strategies does not match the actual building perfectly, measured utility costs savings relative to conventional building operation can be substantial. This requires that the facility under control lends itself to passive storage utilization and the building model

  8. Event-Related Beta EEG Changes During Active, Passive Movement and Functional Electrical Stimulation of the Lower Limb.

    PubMed

    Qiu, Shuang; Yi, Weibo; Xu, Jiapeng; Qi, Hongzhi; Du, Jingang; Wang, Chunfang; He, Feng; Ming, Dong

    2016-02-01

    A number of electroencephalographic (EEG) studies have reported on event-related desynchronization/synchronization (ERD/ERS) during active movements, passive movements, and the movements induced by functional electrical stimulation (FES). However, the quantitative differences in ERD values and affected frequency bands associated with the lower limb have not been discussed. The goal of this paper was to quantitatively compare the ERD patterns during active movement, passive movement and FES-induced movement of the lower limb. 64-channel EEG signals were recorded to investigate the brain oscillatory patterns during active movement, passive movement and FES-induced movement of the lower limb in twelve healthy subjects. And passive movement and FES-induced movement were also performed in a hemiplegic stroke patient. For healthy subjects, FES-induced movement presented significantly higher characteristic frequency of central beta ERD while there was no significant difference in ERD values compared with active or passive movement. Meanwhile, beta ERD values of FES-induced movement were significantly correlated with those of active movement, and spatial distribution of beta ERD pattern for FES-induced movement was more correlated with that for active movement. In addition, the stroke patient presented central ERD patterns during FES-induced movement, while no ERD with similar frequencies could be found during passive movement. This work implies that the EEG oscillatory pattern under FES-induced movement tends more towards active movement instead of passive movement. The quantification of ERD patterns could be expected as a potential technique to evaluate the brain response during FES-induced movement. PMID:26441422

  9. Considerations for an active and passive scanner to assay nuclear waste drums

    SciTech Connect

    Martz, H.E.; Azevedo, S.G.; Roberson, G.P.; Schneberk, D.J.; Koenig, Z.M.; Camp, D.C. )

    1990-06-08

    Radioactive wastes are generated at many DOE laboratories, military facilities, fuel fabrication and enrichment plants, reactors, hospitals, and university research facilities. At all of these sites, wastes must be separated, packaged, categorized, and packed into some sort of container--usually 208-L (55-gal) drums--for shipment to waste-storage sites. Prior to shipment, the containers must be labeled, assayed, and certified; the assay value determines the ultimate disposition of the waste containers. An accurate nondestructive assay (NDA) method would identify all the radioisotopes present and provide a quantitative measurement of their activity in the drum. In this way, waste containers could be routed in the most cost-effective manner and without having to reopen them. Currently, the most common gamma-ray method used to assay nuclear waste drums is segmented gamma-ray scanning (SGS) spectrometer that crudely measures only the amount of {sup 235}U or {sup 239}Pu present in the drum. This method uses a spatially-averaged, integrated, emitted gamma-ray-intensity value. The emitted intensity value is corrected by an assumed constant-attenuation value determined by a spatially-averaged, transmission (or active) measurement. Unfortunately, this typically results in an inaccurate determination of the radioactive activities within a waste drum because this measurement technique is valid only for homogeneous-attenuation or known drum matrices. However, since homogeneous-attenuation matrices are not common and may be unknown, other NDA techniques based on active and Passive CT (A PCT) are under development. The active measurement (ACT) yields a better attenuation matrix for the drum, while the passive measurement (PCT) more accurately determines the identity of the radioisotopes present and their activities. 9 refs., 2 figs.

  10. Pair and Cluster Formation in Hybrid Active-Passive Matter Suspensions

    NASA Astrophysics Data System (ADS)

    Krafnick, Ryan; Garcia, Angel

    2015-03-01

    Systems composed of self-propelling entities, dubbed active matter, are ubiquitous in nature, from flocks of birds and schools of fish to swarms of bacteria and catalytic nanomotors. These systems (both biological and industrial) have applications ranging from micron-scale cargo manipulation and directed transport to water remediation and material processing. When added to a solution with passive (non-self-propelling) particles, active matter leads to new and altered system properties. For example, the diffusion of passive particles increases by orders of magnitude in typical systems, leading to a raised effective temperature. Additionally, particles that normally repel each other exhibit effective attractions which can lead to pair formation and clustering. The nature of these effects depends on both the mechanical collisions of swimmers and the hydrodynamic flow fields they propagate. We computationally examine the effect and dependence of various system parameters, such as particle shape and density, on these properties. This work was funded by NIH grant GM086801 and NSF grant MCB-1050966.

  11. Clicks, whistles and pulses: Passive and active signal use in dolphin communication

    NASA Astrophysics Data System (ADS)

    Herzing, Denise L.

    2014-12-01

    The search for signals out of noise is a problem not only with radio signals from the sky but in the study of animal communication. Dolphins use multiple modalities to communicate including body postures, touch, vision, and most elaborately sound. Like SETI radio signal searches, dolphin sound analysis includes the detection, recognition, analysis, and interpretation of signals. Dolphins use both passive listening and active production to communicate. Dolphins use three main types of acoustic signals: frequency modulated whistles (narrowband with harmonics), echolocation (broadband clicks) and burst pulsed sounds (packets of closely spaced broadband clicks). Dolphin sound analysis has focused on frequency-modulated whistles, yet the most commonly used signals are burst-pulsed sounds which, due to their graded and overlapping nature and bimodal inter-click interval (ICI) rates are hard to categorize. We will look at: 1) the mechanism of sound production and categories of sound types, 2) sound analysis techniques and information content, and 3) examples of lessons learned in the study of dolphin acoustics. The goal of this paper is to provide perspective on how animal communication studies might provide insight to both passive and active SETI in the larger context of searching for life signatures.

  12. Comparative study of torque expression among active and passive self-ligating and conventional brackets

    PubMed Central

    Franco, Érika Mendonça Fernandes; Valarelli, Fabrício Pinelli; Fernandes, João Batista; Cançado, Rodrigo Hermont; de Freitas, Karina Maria Salvatore

    2015-01-01

    Abstract Objective: The aim of this study was to compare torque expression in active and passive self-ligating and conventional brackets. Methods: A total of 300 segments of stainless steel wire 0.019 x 0.025-in and six different brands of brackets (Damon 3MX, Portia, In-Ovation R, Bioquick, Roth SLI and Roth Max) were used. Torque moments were measured at 12°, 24°, 36° and 48°, using a wire torsion device associated with a universal testing machine. The data obtained were compared by analysis of variance followed by Tukey test for multiple comparisons. Regression analysis was performed by the least-squares method to generate the mathematical equation of the optimal curve for each brand of bracket. Results: Statistically significant differences were observed in the expression of torque among all evaluated bracket brands in all evaluated torsions (p < 0.05). It was found that Bioquick presented the lowest torque expression in all tested torsions; in contrast, Damon 3MX bracket presented the highest torque expression up to 36° torsion. Conclusions: The connection system between wire/bracket (active, passive self-ligating or conventional with elastic ligature) seems not to interfere in the final torque expression, the latter being probably dependent on the interaction between the wire and the bracket chosen for orthodontic mechanics. PMID:26691972

  13. Comparison of active and passive microwave signatures of Arctic sea ice

    NASA Technical Reports Server (NTRS)

    Drinkwater, M. R.; Crawford, J. P.; Cavalieri, D. J.; Holt, B.; Carsey, F. D.

    1990-01-01

    In March 1988, overlapping active and passive microwave instrument data were acquired over Arctic sea ice using the NASA DC-8 aircraft equipped with multifrequency, variable polarization SAR and radiometer. Flights were conducted as a series of coordinated underflights of the DMSP SSM/I satellite radiometer in order to validate ice products derived from the SSM/I radiances. Subsequent flights by an NRL P-3 aircraft enabled overlapping high-resolution, single frequency image data to be acquired over the same regions using a Ka-band scanning microwave radiometer. In this paper, techniques are discussed for the accurate coregistration of the three aircraft datasets. Precise coregistration to an accuracy of 100 m plus or minus 25 m has, for the first time, enabled the detailed comparison of temporally and spatially coincident active and passive airborne microwave datasets. Preliminary results from the intercomparisons indicate that the SAR has highly frequency- and polarization-dependent signatures, which at 5.3 GHz (C-band) show an extremely high correlation with the 37 GHz radiometric temperatures.

  14. Active and Passive Interferometric Fringe Stabilization for Quantum Communications in Space

    NASA Astrophysics Data System (ADS)

    Chapman, Joseph; Graham, Trent; Kwiat, Paul

    2015-05-01

    In interferometry, the relative phase between the paths is liable to drift over time due to environmental factors, i.e., vibrations in the components and from turbulence and temperature fluctuations in the air. If time-bin encoded photons are received from a moving space platform, e.g., a satellite or the International Space Station, there would be an additional large relative temporal shift because of the movement of the source toward or away from the receiver. This shift would alter the temporal coherence of adjacent timebins-as measured by a suitable temporally-unbalanced interferometer-in addition to the relative phase errors from the environment. To achieve accurate measurements in this situation, the interferometer needs to be stabilized against phase drifts. We have employed an active and passive stabilization scheme for a double unbalanced Mach-Zehnder interferometer configuration; while passive damping reduces most of the phase drift due to vibrations and fluctuations from the air, we designed and implemented an active feedback correction system to stabilize the remaining phase drift and the simulated temporal drift.

  15. The Development of an Intelligent Hybrid Active-passive Vibration Isolator

    NASA Astrophysics Data System (ADS)

    Shuai, Changgeng; Ma, Jianguo; Rustighi, Emiliano

    2016-09-01

    A hybrid active-passive vibration isolator made up of electromagnetic actuator and air spring in parallel can be used to effectively isolate the broadband and line spectrum vibration of mechanical equipment simultaneously. However, due to its reliability and safety problems caused by the impact, its application in ships is limited. In this paper, an impact- resistant structure and an air gap self-sensing method of the passive-active hybrid vibration isolator are proposed and developed on the base of modelling, simulation and analysis. A thin magnetic rubber is filled into the air gap of electromagnetic actuator, which can avoid rigid collision between the armature and the permanent magnet under the action of impact. A suspension armature structure including pre-compression spring is suggested, which can automatically compensate the deformation caused by impact and protect the coil and permanent magnet from impact damage. An air gap self-sensing method is developed through detecting the voltage between the input and output terminals of actuator, which is verified by experiments.

  16. Nd:YAG laser with passive-active mode-locking

    NASA Astrophysics Data System (ADS)

    Zhao, Weijiang; Chen, Zhenlei; Ren, Deming; Qu, Yanchen; Mo, Shuang; Huang, Jinjer; Andreev, Yury M.; Gorobets, Vadim A.; Petukhov, Vladimir O.; Zemlyanov, Aleksei A.

    2008-03-01

    All solid-state flash-lamp pumped passive-active mode-locked Nd3+:YAG laser is designed and experimentally studded. Saturation absorber Cr4+:YAG with initial transparency 25 and 47% are used as a passive Q-switcher and acousto-optical fused quartz modulator as an active mode-locker. Efficient length of the laser cavity with fixed mirror positions (1.45 m spaced) is droved by changes of 100% flat mirror for concave mirrors with different focus lengths. Changeable output mirrors with transparencies of 15 and 50% are used. Driving of the cavity parameters, laser and acousto-optical modulator power supply voltages let us to control output pulse train and single pulse parameters. As it goes from the analyses of oscillograms fixed with pyroelectric detector (τ=0.5 ns) and 1 GHz oscilloscope, over 95% of pulse output energy has been mode-locked. Average duration of the pulse train envelope of 5 to 50 single pulses at FWHM has been droved within 50 to 600 ns. When this single pulse duration is controlled but did not exceed 2 ns.

  17. Passive and active ion transport by the urinary bladder of a euryhaline flounder.

    PubMed

    Demarest, J R; Machen, T E

    1984-04-01

    The effects of voltage clamping on the flux ratios and unidirectional and net fluxes of Na and Cl were used to gain insight into the mechanisms of active and passive ion transport across urinary bladders isolated from seawater-(SW) and freshwater-acclimated (FW) flounder, Platichthys stellatus. Although the transepithelial conductance (Gt = 2.77 mS X cm-2) of FW bladders was much greater than that of SW bladders (Gt = 0.40 mS X cm-2), the current-voltage relationships of both SW and FW bladders were markedly nonlinear. Under short-circuit conditions there was a large difference in the serosal-to-mucosal Na flux (JNasm) between SW (0.10 mueq X cm-2 X h-1) and FW (1.71 mueq X cm-2 X h-1) bladders, but their mannitol permeabilities were identical. The results indicate that 1) the paracellular pathway of both SW and FW bladders is Cl selective and Cl movements through the shunt account for a maximum of 90% of Gt in SW bladders and 19% in FW bladders; 2) the larger Gt of FW bladders is due to greater conductance of the apical cell membrane; 3) the majority of the passive ion movement across these epithelia proceeds through nonconductive, presumably transcellular, pathways; and 4) active transport of Na and Cl occurs by neutral coupling to each other and to other unidentified ions.

  18. A reliability study on brain activation during active and passive arm movements supported by an MRI-compatible robot.

    PubMed

    Estévez, Natalia; Yu, Ningbo; Brügger, Mike; Villiger, Michael; Hepp-Reymond, Marie-Claude; Riener, Robert; Kollias, Spyros

    2014-11-01

    In neurorehabilitation, longitudinal assessment of arm movement related brain function in patients with motor disability is challenging due to variability in task performance. MRI-compatible robots monitor and control task performance, yielding more reliable evaluation of brain function over time. The main goals of the present study were first to define the brain network activated while performing active and passive elbow movements with an MRI-compatible arm robot (MaRIA) in healthy subjects, and second to test the reproducibility of this activation over time. For the fMRI analysis two models were compared. In model 1 movement onset and duration were included, whereas in model 2 force and range of motion were added to the analysis. Reliability of brain activation was tested with several statistical approaches applied on individual and group activation maps and on summary statistics. The activated network included mainly the primary motor cortex, primary and secondary somatosensory cortex, superior and inferior parietal cortex, medial and lateral premotor regions, and subcortical structures. Reliability analyses revealed robust activation for active movements with both fMRI models and all the statistical methods used. Imposed passive movements also elicited mainly robust brain activation for individual and group activation maps, and reliability was improved by including additional force and range of motion using model 2. These findings demonstrate that the use of robotic devices, such as MaRIA, can be useful to reliably assess arm movement related brain activation in longitudinal studies and may contribute in studies evaluating therapies and brain plasticity following injury in the nervous system.

  19. The Evaluation of the Safety Benefits of Combined Passive and On-Board Active Safety Applications

    PubMed Central

    Page, Yves; Cuny, Sophie; Zangmeister, Tobias; Kreiss, Jens-Peter; Hermitte, Thierry

    2009-01-01

    One of the objectives of the European TRACE project (TRaffic Accident Causation in Europe, 2006–2008) was to estimate the proportion of injury accidents that could be avoided and/or the proportion of injury accidents where the severity could be mitigated for on-the-market safety applications, if 100 % of the car fleet would be equipped with them. We have selected for evaluation the Electronic Stability Control (ESC) and the Emergency Brake Assist (EBA) applications. As for passive safety systems, recent cars are designed to offer overall safety protection. Car structure, load limiters, front airbags, side airbags, knee airbags, pretensioners, padding and non aggressive structures in the door panel, the dashboard, the windshield, the seats, and the head rest also contribute to applying more protection. The whole safety package is very difficult to evaluate separately, one element independently segmented from the others. We decided to consider evaluating the effectivenessof the whole passive safety package, This package,, for the sake of simplicity, was the number of stars awarded at the Euro NCAP testing. The challenges were to compare the effectiveness of some safety configuration SC I, with the effectiveness of a different safety configuration SC II. A safety configuration is understood as a package of safety functions. Ten comparisons have been carried out such as the evaluation of the safety benefit of a fifth star given that the car has four stars and an EBA. The main outcome of this analysis is that any addition of a passive or active safety function selected in this analysis is producing increased safety benefits. For example, if all cars were five stars fitted with EBA and ESC, instead of four stars without ESC and EBA, injury accidents would be reduced by 47.2% for severe injuries and 69.5% for fatal injuries. PMID:20184838

  20. The evaluation of the safety benefits of combined passive and on-board active safety applications.

    PubMed

    Page, Yves; Cuny, Sophie; Zangmeister, Tobias; Kreiss, Jens-Peter; Hermitte, Thierry

    2009-10-01

    One of the objectives of the European TRACE project (TRaffic Accident Causation in Europe, 2006-2008) was to estimate the proportion of injury accidents that could be avoided and/or the proportion of injury accidents where the severity could be mitigated for on-the-market safety applications, if 100 % of the car fleet would be equipped with them. We have selected for evaluation the Electronic Stability Control (ESC) and the Emergency Brake Assist (EBA) applications. As for passive safety systems, recent cars are designed to offer overall safety protection. Car structure, load limiters, front airbags, side airbags, knee airbags, pretensioners, padding and non aggressive structures in the door panel, the dashboard, the windshield, the seats, and the head rest also contribute to applying more protection. The whole safety package is very difficult to evaluate separately, one element independently segmented from the others. We decided to consider evaluating the effectiveness of the whole passive safety package, This package,, for the sake of simplicity, was the number of stars awarded at the Euro NCAP testing. The challenges were to compare the effectiveness of some safety configuration SC I, with the effectiveness of a different safety configuration SC II. A safety configuration is understood as a package of safety functions. Ten comparisons have been carried out such as the evaluation of the safety benefit of a fifth star given that the car has four stars and an EBA. The main outcome of this analysis is that any addition of a passive or active safety function selected in this analysis is producing increased safety benefits. For example, if all cars were five stars fitted with EBA and ESC, instead of four stars without ESC and EBA, injury accidents would be reduced by 47.2% for severe injuries and 69.5% for fatal injuries. PMID:20184838

  1. Effect of temperature and active biogas process on passive separation of digested manure.

    PubMed

    Kaparaju, P; Angelidaki, I

    2008-03-01

    The objective of the study was to identify the optimum time interval for effluent removal after temporarily stopping stirring in otherwise continuously stirred tank reactors. Influence of temperature (10 and 55 degrees C) and active biogas process on passive separation of digested manure, where no outside mechanical or chemical action was used, within the reactor was studied in three vertical settling columns (100 cm deep). Variations in solids and microbial distribution at top, middle and bottom layers of column were assessed over a 15 day settling period. Results showed that best solids separation was achieved when digested manure was allowed to settle at 55 degrees C with active biogas process (pre-incubated at 55 degrees C) compared to separation at 55 degrees C without active biogas process (autoclaved at 120 degrees C, for 20 min) or at 10 degrees C with active biogas process. Maximum solids separation was noticed 24h after settling in column incubated at 55 degrees C, with active biogas process. Microbiological analyses revealed that proportion of Archaea and Bacteria, absent in the autoclaved material, varied with incubation temperature, time and sampling depth. Short rod shaped bacteria dominated at 55 degrees C, while long rod shaped bacteria dominated at 10 degrees C. Methanosarcinaceae were seen more abundant in the surface layer at 55 degrees C while it was seen more common in the top and bottom layers at 10 degrees C. Thus, passive separation of digester contents within the reactor can be used effectively as an operating strategy to optimize biogas production by increasing the solids and biomass retention times. A minimum of 1-2h "non-stirring" period appears to be optimal time before effluent removal in plants where extraction is batch-wise 2-4 times a day.

  2. Active and passive electrical and seismic time-lapse monitoring of earthen embankments

    NASA Astrophysics Data System (ADS)

    Rittgers, Justin Bradley

    In this dissertation, I present research involving the application of active and passive geophysical data collection, data assimilation, and inverse modeling for the purpose of earthen embankment infrastructure assessment. Throughout the dissertation, I identify several data characteristics, and several challenges intrinsic to characterization and imaging of earthen embankments and anomalous seepage phenomena, from both a static and time-lapse geophysical monitoring perspective. I begin with the presentation of a field study conducted on a seeping earthen dam, involving static and independent inversions of active tomography data sets, and self-potential modeling of fluid flow within a confined aquifer. Additionally, I present results of active and passive time-lapse geophysical monitoring conducted during two meso-scale laboratory experiments involving the failure and self-healing of embankment filter materials via induced vertical cracking. Identified data signatures and trends, as well as 4D inversion results, are discussed as an underlying motivation for conducting subsequent research. Next, I present a new 4D acoustic emissions source localization algorithm that is applied to passive seismic monitoring data collected during a full-scale embankment failure test. Acoustic emissions localization results are then used to help spatially constrain 4D inversion of collocated self-potential monitoring data. I then turn to time-lapse joint inversion of active tomographic data sets applied to the characterization and monitoring of earthen embankments. Here, I develop a new technique for applying spatiotemporally varying structural joint inversion constraints. The new technique, referred to as Automatic Joint Constraints (AJC), is first demonstrated on a synthetic 2D joint model space, and is then applied to real geophysical monitoring data sets collected during a full-scale earthen embankment piping-failure test. Finally, I discuss some non-technical issues related to

  3. Duration of active and colostrum-derived passive antibodies to bovine viral diarrhea virus in calves.

    PubMed Central

    Coria, M F; McClurkin, A W

    1978-01-01

    Duration of active and colostrum-derived passive antibodies to bovine viral diarrhea virus was studied in 14 calves. Five calves born with actively induced antibodies to bovine viral diarrhea virus retained high titers during the year of observation. Colostrum-derived antibodies to bovine viral diarrhea virus in nine calves declined at an expected rate for the first four to six months of age. However, titers of six of these calves increased at five to eight months of age and either remained constant or increased through one year of age. Bovine viral diarrhea virus antibody titers of the other three calves declined at a constant rate to less than 1:4 by nine to 12 months of age. PMID:208738

  4. Active and passive Brownian motion of charged particles in two-dimensional plasma models

    SciTech Connect

    Dunkel, Joern; Ebeling, Werner; Trigger, Sergey A.

    2004-10-01

    The dynamics of charged Coulomb grains in a plasma is numerically and analytically investigated. Analogous to recent experiments, it is assumed that the grains are trapped in an external parabolic field. Our simulations are based on a Langevin model, where the grain-plasma interaction is realized by a velocity-dependent friction coefficient and a velocity-independent diffusion coefficient. In addition to the ordinary case of positive (passive) friction between grains and plasma, we also discuss the effects of negative (active) friction. The latter case seems particularly interesting, since recent analytical calculations have shown that friction coefficients with negative parts may appear in some models of ion absorption by grains as well as in models of ion-grain scattering. Such negative friction may cause active Brownian motions of the grains. As our computer simulations show, the influence of negative friction leads to the formation of various stationary modes (rotations, oscillations), which, to some extent, can also be estimated analytically.

  5. Antibacterial performance of polypropylene nonwoven fabric wound dressing surfaces containing passive and active components

    NASA Astrophysics Data System (ADS)

    Xin, Zhirong; Du, Shanshan; Zhao, Chunyu; Chen, Hao; Sun, Miao; Yan, Shunjie; Luan, Shifang; Yin, Jinghua

    2016-03-01

    A growing number of wound dressing-related nosocomial infections necessitate the development of novel antibacterial strategies. Herein, polypropylene non-woven fabric (PPNWF) was facilely modified with passive and active antibacterial components, namely photografting polymerization both N-Vinyl-2-pyrrolidone (NVP) and glycidyl methacrylate (GMA) monomers, and the introduction of guanidine polymer through the reaction between active amino groups and epoxy groups. The modified samples were confirmed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), respectively. Water contact angle measurement, antibacterial test, platelet and red blood cell adhesion were used to evaluate the hydrophilicity, antibacterial properties and hemocompatibility of the samples. It was found that the antibacterial properties were obviously enhanced, meanwhile significantly suppressing platelet and red blood cell adhesion after the above modification. This PPNWF samples that possess antifouling and antimicrobial properties, have great potential in wound dressing applications.

  6. "Active" and "Passive" Lava Resurfacing Processes on Io: A Comparative Study of Loki Patera and Prometheus

    NASA Technical Reports Server (NTRS)

    Davies, A. G.; Matson, D. L.; Leone, G.; Wilson, L.; Keszthelyi, L. P.

    2004-01-01

    Studies of Galileo Near Infrared Mapping Spectrometer (NIMS) data and ground based data of volcanism at Prometheus and Loki Patera on Io reveal very different mechanisms of lava emplacement at these two volcanoes. Data analyses show that the periodic nature of Loki Patera s volcanism from 1990 to 2001 is strong evidence that Loki s resurfacing over this period resulted from the foundering of a crust on a lava lake. This process is designated passive , as there is no reliance on sub-surface processes: the foundering of the crust is inevitable. Prometheus, on the other hand, displays an episodicity in its activity which we designate active . Like Kilauea, a close analog, Prometheus s effusive volcanism is dominated by pulses of magma through the nearsurface plumbing system. Each system affords views of lava resurfacing processes through modelling.

  7. Hybrid Active-Passive Systems for Control of Aircraft Interior Noise

    NASA Technical Reports Server (NTRS)

    Fuller, Chris R.; Palumbo, Dan (Technical Monitor)

    2002-01-01

    It was proposed to continue with development and application in the two active-passive areas of Active Tuned Vibration Absorbers (ATVA) and smart foam applied to the reduction of interior noise in aircraft. In general the work was focused on making both techniques more efficient, practical and robust thus increasing their application potential. The work was also concerned with demonstrating the potential of these two technologies under realistic implementations as well as understanding the fundamental physics of the systems. The proposed work consisted of a three-year program and was tightly coordinated with related work being carried out in the Structural Acoustics Branch at NASA LaRC. The work was supervised and coordinated through all phases by Prof Chris Fuller of Va Tech.

  8. Solid state active/passive night vision imager using continuous-wave laser diodes and silicon focal plane arrays

    NASA Astrophysics Data System (ADS)

    Vollmerhausen, Richard H.

    2013-04-01

    Passive imaging offers covertness and low power, while active imaging provides longer range target acquisition without the need for natural or external illumination. This paper describes a focal plane array (FPA) concept that has the low noise needed for state-of-the-art passive imaging and the high-speed gating needed for active imaging. The FPA is used with highly efficient but low-peak-power laser diodes to create a night vision imager that has the size, weight, and power attributes suitable for man-portable applications. Video output is provided in both the active and passive modes. In addition, the active mode is Class 1 eye safe and is not visible to the naked eye or to night vision goggles.

  9. Active and passive computed tomography mixed waste focus area final report

    SciTech Connect

    Jackson, J A; Becker, G K; Camp, D C; Decman, D J; Martz, H E; Roberson, G P

    1998-11-06

    The Mixed Waste Focus Area (MWFA) Characterization Development Strategy delineates an approach to resolve technology deficiencies associated with the characterization of mixed wastes. The intent of this strategy is to ensure the availability of technologies to support the Department of Energy's (DOE) mixed-waste, low-level or transuranic (TRU) contaminated waste characterization management needs. To this end the MWFA has defined and coordinated characterization development programs to ensure that data and test results necessary to evaluate the utility of non-destructive assay technologies are available to meet site contact handled waste management schedules. Requirements used as technology development project benchmarks are based in the National TRU Program Quality Assurance Program Plan. These requirements include the ability to determine total bias and total measurement uncertainty. These parameters must be completely evaluated for waste types to be processed through a given nondestructive waste assay system constituting the foundation of activities undertaken in technology development projects. Once development and testing activities have been completed, Innovative Technology Summary Reports are generated to provide results and conclusions to support EM-30, -40, or -60 end user or customer technology selection. The active and passive computed tomography non-destructive assay system is one of the technologies selected for development by the MWFA. Lawrence Livermore National Laboratory (LLNL) has developed the active and passive computed tomography (A&XT) nondestructive assay (NDA) technology to identify and accurately quantify all detectable radioisotopes in closed containers of waste. This technology will be applicable to all types of waste regardless of their classification-low level, transuranic or mixed. Mixed waste contains radioactivity and hazardous organic species. The scope of our technology is to develop a non-invasive waste-drum scanner that employs

  10. Active and passive mode calibration of the Combined Thermal Epithermal Neutron (CTEN) system

    SciTech Connect

    Veilleux, J. M.

    2002-06-01

    The Combined Thermal/Epithermal Neutron (CTEN) non-destructive assay (NDA) system was designed to assay transuranic waste by employing an induced active neutron interrogation and/or a spontaneous passive neutron measurement. This is the second of two papers, and focuses on the passive mode, relating the net double neutron coincidence measurement to the plutonium mass via the calibration constant. National Institute of Standards and Technology (NIST) calibration standards were used and the results verified with NIST-traceable verification standards. Performance demonstration program (PDP) 'empty' 208-L matrix drum was used for the calibration. The experimentally derived calibration constant was found to be 0.0735 {+-} 0.0059 g {sup 240}Pu effective per unit response. Using this calibration constant, the Waste Isolation Pilot Plant (WIPP) criteria was satisfied with five minute waste assays in the range from 3 to 177g Pu. CTEN also participated in the PDP Cycle 8A blind assay with organic sludge and metal matrices and passed the criteria for accuracy and precision in both assay modes. The WIPP and EPA audit was completed March 1, 2002 and full certification is awaiting the closeout of one finding during the audit. With the successful closeout of the audit, the CTEN system will have shown that it can provide very fast assays (five minutes or less) of waste in the range from the minimum detection limit (about 2 mg Pu) to 177 g Pu.

  11. Experimental Studies of Active and Passive Flow Control Techniques Applied in a Twin Air-Intake

    PubMed Central

    Joshi, Shrey; Jindal, Aman; Maurya, Shivam P.; Jain, Anuj

    2013-01-01

    The flow control in twin air-intakes is necessary to improve the performance characteristics, since the flow traveling through curved and diffused paths becomes complex, especially after merging. The paper presents a comparison between two well-known techniques of flow control: active and passive. It presents an effective design of a vortex generator jet (VGJ) and a vane-type passive vortex generator (VG) and uses them in twin air-intake duct in different combinations to establish their effectiveness in improving the performance characteristics. The VGJ is designed to insert flow from side wall at pitch angle of 90 degrees and 45 degrees. Corotating (parallel) and counterrotating (V-shape) are the configuration of vane type VG. It is observed that VGJ has the potential to change the flow pattern drastically as compared to vane-type VG. While the VGJ is directed perpendicular to the side walls of the air-intake at a pitch angle of 90 degree, static pressure recovery is increased by 7.8% and total pressure loss is reduced by 40.7%, which is the best among all other cases tested for VGJ. For bigger-sized VG attached to the side walls of the air-intake, static pressure recovery is increased by 5.3%, but total pressure loss is reduced by only 4.5% as compared to all other cases of VG. PMID:23935422

  12. Experimental studies of active and passive flow control techniques applied in a twin air-intake.

    PubMed

    Paul, Akshoy Ranjan; Joshi, Shrey; Jindal, Aman; Maurya, Shivam P; Jain, Anuj

    2013-01-01

    The flow control in twin air-intakes is necessary to improve the performance characteristics, since the flow traveling through curved and diffused paths becomes complex, especially after merging. The paper presents a comparison between two well-known techniques of flow control: active and passive. It presents an effective design of a vortex generator jet (VGJ) and a vane-type passive vortex generator (VG) and uses them in twin air-intake duct in different combinations to establish their effectiveness in improving the performance characteristics. The VGJ is designed to insert flow from side wall at pitch angle of 90 degrees and 45 degrees. Corotating (parallel) and counterrotating (V-shape) are the configuration of vane type VG. It is observed that VGJ has the potential to change the flow pattern drastically as compared to vane-type VG. While the VGJ is directed perpendicular to the side walls of the air-intake at a pitch angle of 90 degree, static pressure recovery is increased by 7.8% and total pressure loss is reduced by 40.7%, which is the best among all other cases tested for VGJ. For bigger-sized VG attached to the side walls of the air-intake, static pressure recovery is increased by 5.3%, but total pressure loss is reduced by only 4.5% as compared to all other cases of VG.

  13. Passive and active imaging at 94 GHz for environmental remote sensing

    NASA Astrophysics Data System (ADS)

    Macfarlane, David G.; Robertson, Duncan A.; Cassidy, Scott L.; Odbert, Henry M.; James, Mike R.; Pinkerton, Harry; Wadge, Geoff

    2013-05-01

    We report on the use of the All-weather Volcano Topography Imaging Sensor (AVTIS) 94 GHz dual mode radar/radiometric imager for environmental monitoring. The FMCW radar yields 3D maps of the terrain whilst the passive radiometer records brightness temperature maps of the scene. AVTIS is a low power portable instrument and has been used operationally to survey terrain at ranges up to 6 km. AVTIS was originally developed for the ground-based measurement of active volcanoes and has been used successfully to measure the Arenal Volcano in Costa Rica and the Soufrière Hills Volcano on Montserrat. However, additional environmental remote sensing applications are emerging for this technology and we will present details of how the instrument is used to perform terrain mapping and thermal surveys of outdoor scenes. The extraction of digital elevation maps is the primary function of the AVTIS radar mode. We review this process covering range drift compensation, radar cross section (RCS) histogram analysis and thresholding, and georeferencing to GPS. Additionally, we will present how careful calibration enables RCS imaging of terrain and the extraction of the intrinsic reflectivity of the terrain material (normalized RCS, or sigma-nought) which can potentially be used to classify terrain types. We have validated the passive mode imagery against infrared thermal imagery and they show good agreement once the differences in spatial resolution are accounted for. This comparison also reveals differences in propagation due to obscurants (steam, gas, ash) in the two wavebands.

  14. The effects of passive stretching plus vibration on strength and activation of the plantar flexors.

    PubMed

    Miller, Jonathan D; Herda, Trent J; Trevino, Michael A; Mosier, Eric M

    2016-09-01

    This study examined the effects of passive stretching only (PS+CON) and passive stretching with the addition of continuous vibration (VIB) during post-passive stretching tests (PS+VIB) on peak torque (PT), percent voluntary inactivation (%VI), single stimulus twitch torque (TTSINGLE), and doublet stimuli twitch torque (TTDOUBLET) of the plantar flexors at a short (20° plantar flexion (PF)) and long muscle length (15° dorsiflexion (DF)). Fourteen healthy men (age = 22 ± 3 years) performed isometric maximal voluntary contractions at PF and DF, and passive range of motion (PROM) assessments before and after 8 × 30-s passive stretches without (PS+CON) or with VIB (PS+VIB) administered continuously throughout post-passive stretching tests. The passive properties of the muscle tendon unit were assessed pre- and post-passive stretching via PROM, passive torque (PASSTQ), and musculotendinous stiffness (MTS) measurements. PT, TTSINGLE, and TTDOUBLET decreased, whereas, %VI increased following passive stretching at PF and DF (P < 0.05) with no significant differences between PS+CON and PS+VIB. PASSTQ and MTS decreased while PROM increased post-passive stretching during both trials (P < 0.05). The stretching-induced force/torque deficit and increases in %VI were evident following passive stretching at short and long muscle lengths. Although not statistically significant, effect size calculations suggested large and moderate differences in the absolute changes in PT (Cohen's d = 1.14) and %VI (Cohen's d = 0.54) from pre- to post-passive stretching between treatments, with PS+VIB having greater decreases of PT and higher %VI than PS+CON. The decrement in PT following passive stretching may be primarily neural in origin. PMID:27512816

  15. Shelf-Scale Mapping of Fish Distribution Using Active and Passive Acoustics

    NASA Astrophysics Data System (ADS)

    Wall, Carrie C.

    Fish sound production has been associated with courtship and spawning behavior. Acoustic recordings of fish sounds can be used to identify distribution and behavior. Passive acoustic monitoring (PAM) can record large amounts of acoustic data in a specific area for days to years. These data can be collected in remote locations under potentially unsafe seas throughout a 24-hour period providing datasets unattainable using observer-based methods. However, the instruments must withstand the caustic ocean environment and be retrieved to obtain the recorded data. This can prove difficult due to the risk of PAMs being lost, stolen or damaged, especially in highly active areas. In addition, point-source sound recordings are only one aspect of fish biogeography. Passive acoustic platforms that produce low self-generated noise, have high retrieval rates, and are equipped with a suite of environmental sensors are needed to relate patterns in fish sound production to concurrently collected oceanographic conditions on large, synoptic scales. The association of sound with reproduction further invokes the need for such non-invasive, near-real time datasets that can be used to enhance current management methods limited by survey bias, inaccurate fisher reports, and extensive delays between fisheries data collection and population assessment. Red grouper (Epinephelus morio) exhibit the distinctive behavior of digging holes and producing a unique sound during courtship. These behaviors can be used to identify red grouper distribution and potential spawning habitat over large spatial scales. The goal of this research was to provide a greater understanding of the temporal and spatial distribution of red grouper sound production and holes on the central West Florida Shelf (WFS) using active sonar and passive acoustic recorders. The technology demonstrated here establishes the necessary methods to map shelf-scale fish sound production. The results of this work could aid resource

  16. Bone structure and quality preserved by active versus passive muscle exercise in 21 days tail-suspended rats

    NASA Astrophysics Data System (ADS)

    Luan, Huiqin; Sun, Lian-wen; Fan, Yu-bo

    2012-07-01

    Humans in Space suffer from microgravity-induced attenuated bone strength that needs to be addressed by on-orbit exercise countermeasures. However, exercise prescriptions so far did not adequately counteract the bone loss of astronauts in spaceflight because even active muscle contractions were converted to passive mode during voluntary bouts. We tested our hypothesis in unloaded rat hind limb following twenty-one days of tail-suspension (TS) combined with exercise using a hind limb stepper device designed by our group. Female Sprague Dawley rats (250g b.wt.) were divided into four groups (n=5, each): TS-only (hind limb unloading), TS plus passive mode exercise (TSP) induced by mechanically-forced passive hind limb lifting, TS plus active mode exercise (TSA) entrained by plantar electrostimulation, and control (CON) group. Standard measures of bone (e.g., mineral density, trabecular microstructure, biomechanics and ash weight) were monitored. Results provided that the attenuated properties of unloaded hind limb bone in TS-rats were more effectively supported by active mode than by passive mode motions. We here propose a modified exercise regimen combined with spontaneous muscle contractions thereby considering the biodynamic demands of both muscle and bone during resistive-load exercise in microgravity. Keywords: rat, BMD, DXA, passive exercise, active exercise, bone loss, tail suspension, spaceflight analogue, exercise countermeasure.

  17. Study of passive and active optical waveguides: Synthesis, processing and characterization of materials

    NASA Astrophysics Data System (ADS)

    Yoshida, Makoto

    Photonics uses photons for information and image processing, and has been touted as the technology of the 21 st century. An optical waveguide is a key component of an optical integrated circuit which is the optical analog of an electrical integrated circuit (IC). Electrical transistor IC technology resulted in an enormous impact on society, and it changed our life styles from the age of the vacuum tube. The advent of the optical integrated circuit is expected to have the same impact on society as the electronic IC. Various optical circuit elements are interrelated to materials, therefore, the study and the better understanding of materials and processing have been receiving a great deal of attention. My research focuses on the study of optical waveguide materials and their processings in terms of passive and active optical waveguides. The first target was to establish a method for measuring the refractive index and optical propagation loss of optical waveguides. The second target was to develop passive waveguide materials which can route, split and combine optical signals on a substrate. There are several requirements for waveguiding, such as high optical transparency, proper refractive index, and proper thickness. The sol-gel technique was used to meet the requirements, and several types of organic: inorganic composite materials were developed. The third target involved the development of processing methods to fabricate channel waveguides using the above-mentioned passive and active waveguide materials. Selective laser densification was developed for sol-gel composite materials. Use of trenched substrates and photobleaching were also studied. The last target was to develop an active material which could process optical signals using the electrooptic effect. A crosslinked urethane polymer with a newly synthesized chromophore was used due to its high thermal stability and optical transparency. In order to obtain second order nonlinearity, macroscopic molecular

  18. Retrievals of Falling Snow from Satellite-borne Active and Passive Sensors

    NASA Astrophysics Data System (ADS)

    Skofronick-Jackson, Gail; Munchak, S. Joseph; Johnson, Benjamin

    2013-04-01

    Precipitation, including rain and snow, is a critical part of the Earth's energy and hydrology cycles. Precipitation impacts latent heating profiles locally while global circulation patterns distribute precipitation and energy from the equator to the poles. For the hydrological cycle, falling snow is a primary contributor in northern latitudes during the winter seasons. Falling snow is the source of snow pack accumulations that provide fresh water resources for many communities in the world. Furthermore, falling snow impacts society by causing transportation disruptions during severe snow events. In order to collect information on the complete global precipitation cycle, both liquid and frozen precipitation must be collected. The Global Precipitation Measurement (GPM) mission's Core satellite, scheduled for launch in 2014, is well designed to detect and estimate falling snow. The GPM core carries a passive radiometer with frequencies (10-183 GHz) and an active radar with Ku- and Ka-band frequencies. Combined with the 65 degree inclination of the GPM Core satellite, these instruments allow for the GPM Core to sense and retrieve information about falling snow and light rain in regions of the earth where snow is common. The GPM Core's comprehensive active and passive channel set will also allow it to serve as a unifying reference for GPM constellation radiometer satellites. Since falling snow from space is the next precipitation measurement challenge from space, information is needed to guide retrieval algorithm development for these current and future missions. This information includes thresholds of detection for various sensor channel configurations, sensitivity to macroscale snow event system characteristics, and sensitivity to microscale snowflake particle characteristics. While the work in this area will continue for many years to come, our group has made substantial progress in this area by identifying minimum detectable melted rates of ~0.5 mm/hr. Results will

  19. Retrievals of Falling Snow from Satellite-borne Active and Passive Sensors

    NASA Astrophysics Data System (ADS)

    Jackson, Gail; Munchak, S. Joseph; Johnson, Benjamin

    2014-05-01

    Precipitation, including rain and snow, is a critical part of the Earth's energy and hydrology cycles. Precipitation impacts latent heating profiles locally while global circulation patterns distribute precipitation and energy from the equator to the poles. For the hydrological cycle, falling snow is a primary contributor in northern latitudes during the winter seasons. Falling snow is the source of snow pack accumulations that provide fresh water resources for many communities in the world. Furthermore, falling snow impacts society by causing transportation disruptions during severe snow events. In order to collect information on the complete global precipitation cycle, both liquid and frozen precipitation must be collected. The Global Precipitation Measurement (GPM) mission's Core satellite, scheduled for launch in February 2014, is well designed to detect and estimate falling snow. The GPM core carries a passive radiometer with frequencies (10-183 GHz) and an active radar with Ku- and Ka-band frequencies. Combined with the 65o inclination of the GPM Core satellite, these instruments allow for the GPM Core to sense and retrieve information about falling snow and light rain in regions of the earth where snow is common. The GPM Core's comprehensive active and passive channel set will also allow it to serve as a unifying reference for GPM constellation radiometer satellites. Since falling snow from space is the next precipitation measurement challenge from space, information is needed to guide retrieval algorithm development for these current and future missions. This information includes thresholds of detection for various sensor channel configurations, sensitivity to macroscale snow event system characteristics, and sensitivity to microscale snowflake particle characteristics. While the work in this area will continue for many years to come, our group has made substantial progress in this area by identifying minimum detectable melted rates of ~0.5 mm hr-1. Results

  20. Intercomparison of active, passive and continuous instruments for radon and radon progeny

    SciTech Connect

    George, A.C.; Knutson, E.O.; Tu, K.W.; Fisenne, I.

    1995-12-31

    The DOE/OHER radon, thoron and progeny exposure and test facility was set up in 1993 to provide a well controlled, airtight and uniform environment. The new calibration chamber is the primary test facility at the Environmental Measurements Laboratory (EML), in which a large number of an diverse types of monitoring instruments can be accomodated for calibration, evaluation and intercomparison purposes. The test chamber is environmentally controlled for temperature and humidity. Monodispersed or polydispersed aerosols are generated to study radon and thoron progeny attachment and behavior and to investigate instrument performance under different conditions of exposure. Also, particle size measurements are performed to develop techniques for the assessment of the health risk from the inhalation of radon and thoron progeny. The results from the May 1995 intercomparison for active, passive and continuous instruments for radon and radon progeny are presented. Instruments that measure radon were represented by 13 participants with open face and diffusion barrier activated carbon collectors, 10 with nuclear alpha track detectors, 9 with short-term and long-term electret/ionization chambers and 13 with active and passive commercial electronic continuous monitors. For radon progeny, there were 4 participants that came in person to take part in the grab sampling methodology for measuring individual radon progeny and the potential alpha energy (PAEC). The results indicate that all the tested instruments that measure radon are in good standing. All instruments and methods used for grab sampling for radon progeny did very well. However, most of the continuous and integrating electronic instruments used for PAEC (WL), appear to underestimate the potential risk from radon progeny when the concentration of particles onto which the radon progeny are attached is <5,000 cc{sup -1}.

  1. Intercomparison of active and passive instruments for radon and radon progeny in North America

    SciTech Connect

    George, A.C.; Tu, Keng-Wu; Knutson, E.O.

    1995-02-01

    An intercomparison exercise for radon and radon progeny instruments and methods was held at the Environmental Measurements Laboratory (EML) from April 22--May 2, 1994. The exercise was conducted in the new EML radon test and calibration facility in which conditions of exposure are very well controlled. The detection systems of the intercompared instruments consisted of. (1) pulse ionization chambers, (2) electret ionization chambers, (3) scintillation detectors, (4) alpha particle spectrometers with silicon diodes, surface barrier or diffused junction detectors, (5) registration of nuclear tracks in solid-state materials, and (6) activated carbon collectors counted by gamma-ray spectrometry or by alpha- and beta-liquid scintillation counting. 23 private firms, government laboratories and universities participated with a 165 passive integrating devices consisting of: Activated carbon collectors, nuclear alpha track detectors and electret ionization chambers, and 11 active and passive continuous radon monitors. Five portable integrating and continuous instruments were intercompared for radon progeny. Forty grab samples for radon progeny were taken by five groups that participated in person to test and evaluate their primary instruments and methods that measure individual radon progeny and the potential alpha energy concentration (PAEC) in indoor air. Results indicate that more than 80% of the measurements for radon performed with a variety of instruments, are within {plus_minus}10% of actual value. The majority of the instruments that measure individual radon progeny and the PAEC gave results that are in good agreement with the EML reference value. Radon progeny measurements made with continuous and integrating instruments are satisfactory with room for improvement.

  2. Can a prescribed turnout conditioning program reduce the differential between passive and active turnout in pre-professional dancers?

    PubMed

    Sherman, Astrid J; Mayall, Erika; Tasker, Susan L

    2014-01-01

    Preliminary and speculative findings are reported on the benefits of a prescribed turnout conditioning program (TCP) designed to facilitate pre-professional dancers' active use of natural turnout potential. While of some debate, it is reported in the literature that many dancers use less turnout than what is available to them when measured passively. Key muscles required to achieve full turnout were the focus of the TCP, and exercises were introduced in a manner that, theoretically, should stimulate appropriate activation patterns for proper turnout biomechanics. A group of female pre-professional dancers (13 to 17 years old, training 20 to 25 hours a week, N = 16) were measured before and after the 7-week program for total passive turnout, total active turnout, passive hip external rotation, and tibial torsion. Statistically and functionally significant improvements were found in both static total active turnout (standing in first position on a large piece of paper) and dynamic total active turnout (standing in first position on rotational Balanced Body discs). These results indicate that the TCP was effective in improving active turnout, thereby reducing the differential between passive and active turnout in pre-professional ballet dancers. Implications are discussed for dancer-specific turnout conditioning programs, the role of cognitive imagery cueing, and emphasis on the importance of quantity with quality in the conditioning and teaching of active turnout. PMID:25474295

  3. Can a prescribed turnout conditioning program reduce the differential between passive and active turnout in pre-professional dancers?

    PubMed

    Sherman, Astrid J; Mayall, Erika; Tasker, Susan L

    2014-01-01

    Preliminary and speculative findings are reported on the benefits of a prescribed turnout conditioning program (TCP) designed to facilitate pre-professional dancers' active use of natural turnout potential. While of some debate, it is reported in the literature that many dancers use less turnout than what is available to them when measured passively. Key muscles required to achieve full turnout were the focus of the TCP, and exercises were introduced in a manner that, theoretically, should stimulate appropriate activation patterns for proper turnout biomechanics. A group of female pre-professional dancers (13 to 17 years old, training 20 to 25 hours a week, N = 16) were measured before and after the 7-week program for total passive turnout, total active turnout, passive hip external rotation, and tibial torsion. Statistically and functionally significant improvements were found in both static total active turnout (standing in first position on a large piece of paper) and dynamic total active turnout (standing in first position on rotational Balanced Body discs). These results indicate that the TCP was effective in improving active turnout, thereby reducing the differential between passive and active turnout in pre-professional ballet dancers. Implications are discussed for dancer-specific turnout conditioning programs, the role of cognitive imagery cueing, and emphasis on the importance of quantity with quality in the conditioning and teaching of active turnout.

  4. Evaluation of the particle infiltration efficiency of three passive samplers and the PS-1 active air sampler

    NASA Astrophysics Data System (ADS)

    Markovic, Milos Z.; Prokop, Sebastian; Staebler, Ralf M.; Liggio, John; Harner, Tom

    2015-07-01

    The particle infiltration efficiencies (PIE) of three passive and one active air samplers were evaluated under field conditions. A wide-range particle spectrometer operating in the 250-4140 nm range was used to acquire highly temporally resolved particle-number and size distributions for the different samplers compared to ambient air. Overall, three of the four evaluated samplers were able to acquire a representative sample of ambient particles with PIEs of 91.5 ± 13.7% for the GAPS Network sampler, 103 ± 15.5% for the Lancaster University sampler, and 89.6 ± 13.4% for a conventional PS-1 high-volume active air sampler (Hi-Vol). Significantly (p = 0.05) lower PIE of 54 ± 8.0% was acquired for the passive sampler used under the MONET program. These findings inform the comparability and use of passive and active samplers for measuring particle-associated priority chemicals in air.

  5. A passive-flow microfluidic device for imaging latent HIV activation dynamics in single T cells

    PubMed Central

    Gearhart, Larisa M.; Miller-Jensen, Kathryn

    2015-01-01

    Quantifying cell-to-cell variability in drug response dynamics is important when evaluating therapeutic efficacy. For example, optimizing latency reversing agents (LRAs) for use in a clinical “activate-and-kill” strategy to purge the latent HIV reservoir in patients requires minimizing heterogeneous viral activation dynamics. To evaluate how heterogeneity in latent HIV activation varies across a range of LRAs, we tracked drug-induced response dynamics in single cells via live-cell imaging using a latent HIV–GFP reporter virus in a clonal Jurkat T cell line. To enable these studies in suspension cells, we designed a simple method to capture an array of single Jurkat T cells using a passive-flow microfluidic device. Our device, which does not require external pumps or tubing, can trap hundreds of cells within minutes with a high retention rate over 12 hours of imaging. Using this device, we quantified heterogeneity in viral activation stimulated by transcription factor (TF) activators and histone deacetylase (HDAC) inhibitors. Generally, TF activators resulted in both faster onset of viral activation and faster rates of production, while HDAC inhibitors resulted in more uniform onset times, but more heterogeneous rates of production. Finally, we demonstrated that while onset time of viral gene expression and rate of viral production together predict total HIV activation, rate and onset time were not correlated within the same individual cell, suggesting that these features are regulated independently. Overall, our results reveal drug-specific patterns of noisy HIV activation dynamics not previously identified in static single-cell assays, which may require consideration for the most effective activate-and-kill regime. PMID:26138068

  6. A passive-flow microfluidic device for imaging latent HIV activation dynamics in single T cells.

    PubMed

    Ramji, Ramesh; Wong, Victor C; Chavali, Arvind K; Gearhart, Larisa M; Miller-Jensen, Kathryn

    2015-09-01

    Quantifying cell-to-cell variability in drug response dynamics is important when evaluating therapeutic efficacy. For example, optimizing latency reversing agents (LRAs) for use in a clinical "activate-and-kill" strategy to purge the latent HIV reservoir in patients requires minimizing heterogeneous viral activation dynamics. To evaluate how heterogeneity in latent HIV activation varies across a range of LRAs, we tracked drug-induced response dynamics in single cells via live-cell imaging using a latent HIV-GFP reporter virus in a clonal Jurkat T cell line. To enable these studies in suspension cells, we designed a simple method to capture an array of single Jurkat T cells using a passive-flow microfluidic device. Our device, which does not require external pumps or tubing, can trap hundreds of cells within minutes with a high retention rate over 12 hours of imaging. Using this device, we quantified heterogeneity in viral activation stimulated by transcription factor (TF) activators and histone deacetylase (HDAC) inhibitors. Generally, TF activators resulted in both faster onset of viral activation and faster rates of production, while HDAC inhibitors resulted in more uniform onset times, but more heterogeneous rates of production. Finally, we demonstrated that while onset time of viral gene expression and rate of viral production together predict total HIV activation, rate and onset time were not correlated within the same individual cell, suggesting that these features are regulated independently. Overall, our results reveal drug-specific patterns of noisy HIV activation dynamics not previously identified in static single-cell assays, which may require consideration for the most effective activate-and-kill regime.

  7. Active Smoking, Passive Smoking, and Risk of Nonalcoholic Fatty Liver Disease (NAFLD): A Population-Based Study in China

    PubMed Central

    Liu, Yu; Dai, Meng; Bi, Yufang; Xu, Min; Xu, Yu; Li, Mian; Wang, Tiange; Huang, Fei; Xu, Baihui; Zhang, Jie; Li, Xiaoying; Wang, Weiqing; Ning, Guang

    2013-01-01

    Background The effect of active smoking on development of nonalcoholic fatty liver disease (NAFLD) is controversial, and there are limited clinical data on the relationship between passive smoking and NAFLD. We investigated whether active and passive smoking are associated with NAFLD. Methods A total of 8580 subjects (2691 men) aged 40 years or older participated in a community-based survey in Shanghai, China. Information on active and passive smoking was collected using a validated questionnaire. NAFLD was diagnosed by abdominal B-mode ultrasound testing and serum liver enzymes. Results NAFLD prevalence was 29.4% in never smokers, 34.2% in former smokers, 27.8% in light smokers (<20 cigarettes/day), 30.8% in moderate smokers (20–39 cigarettes/day), and 43.5% in heavy smokers (≥40 cigarettes/day). Fully adjusted logistic regression analyses revealed that, as compared with never smoking, former and heavy smoking were associated with increased risk of prevalent NAFLD, with odds ratios of 1.45 (95% CI 1.05–2.00) and 2.29 (95% CI 1.30–4.03), respectively. Active smoking and body mass index (BMI) had a synergistic effect on the risk of prevalent NAFLD; the combination of these risk factors was associated with the highest observed odds ratio for NAFLD: 8.58. In never-smoking women, passive smoking during both childhood and adulthood was associated with a 25% increase in the risk of prevalent NAFLD (OR = 1.25, 95% CI 1.05–1.50) as compared with no passive smoking. Conclusions Passive smoking and heavy active smoking are associated with prevalent NAFLD in middle-aged and elderly Chinese. Active smoking and BMI have a synergistic effect on prevalent NAFLD. PMID:23399520

  8. Analysis of time-resolved interaction force mode AFM imaging using active and passive probes.

    PubMed

    Giray Oral, Hasan; Parlak, Zehra; Levent Degertekin, F

    2012-09-01

    We present an in-depth analysis of time-resolved interaction force (TRIF) mode imaging for atomic force microscopy (AFM). A nonlinear model of an active AFM probe, performing simultaneous topography and material property imaging on samples with varying elasticity and adhesion is implemented in Simulink®. The model is capable of simulating various imaging modes, probe structures, sample material properties, tip-sample interaction force models, and actuation and feedback schemes. For passive AFM cantilevers, the model is verified by comparing results from the literature. As an example of an active probe, the force sensing integrated readout and active tip (FIRAT) probe is used. Simulation results indicate that the active and damped nature of FIRAT provides a significant level of control over the force applied to the sample, minimizing sample indentation and topography error. Active tip control (ATC) preserves constant contact time during force control for stable contact while preventing the loss of material property information such as elasticity and adhesive force. Simulation results are verified by TRIF mode imaging of the samples with both soft and stiff regions. PMID:22813887

  9. Stability and variability: indicators for passive stability and active control in a rhythmic task.

    PubMed

    Wei, Kunlin; Dijkstra, Tjeerd M H; Sternad, Dagmar

    2008-06-01

    Using a rhythmic task where human subjects bounced a ball with a handheld racket, fine-grained analyses of stability and variability extricated contributions from open-loop control, noise strength, and active error compensation. Based on stability analyses of a stochastic-deterministic model of the task--a surface contacting the ball by periodic movements--open-loop or dynamic stability was assessed by the acceleration of the racket at contact. Autocovariance analyses of model and data were further used to gauge the contributions of open-loop stability and noise strength. Variability and regression analyses estimated active error compensation. Empirical results demonstrated that experienced actors exploited open-loop stability more than novices, had lower noise strength, and applied more active error compensations. By manipulating the model parameter coefficient of restitution, task stability was varied and showed that actors graded these three components as a function of task stability. It is concluded that actors tune into task stability when stability is high but use more active compensation when stability is reduced. Implications for the neural underpinnings for passive stability and active control are discussed. Further, results showed that stability and variability are not simply the inverse of each other but contain more quantitative information when combined with model analyses.

  10. Active and passive migration in boring isopods Limnoria spp. (Crustacea, Peracarida) from kelp holdfasts

    NASA Astrophysics Data System (ADS)

    Miranda, Leonardo; Thiel, Martin

    2008-10-01

    Many boring isopods inhabit positively buoyant substrata (wood and algae), which float after detachment, permitting passive migration of inhabitants. Based on observations from previous studies, it was hypothesized that juvenile, subadult and male isopods migrate actively, and will rapidly abandon substrata after detachment. In contrast, reproductive females and small offspring were predicted to remain in floating substrata and thus have a high probability to disperse passively via rafting. In order to test this hypothesis, a colonization and an emigration experiment were conducted with giant kelp ( Macrocystis integrifolia), the holdfasts of which are inhabited by boring isopods from the genus Limnoria. A survey of benthic substrata in the kelp forest confirmed that limnoriids inhabited the holdfasts and did not occur in holdfast-free samples. Results of the colonization experiment showed that all life history stages of the boring isopods immigrated into young, largely uncolonized holdfasts, and after 16 weeks all holdfasts were densely colonized. In the emigration experiment, all life history stages of the isopods rapidly abandoned the detached holdfasts — already 5 min after detachment only few individuals remained in the floating holdfasts. After this initial rapid emigration of isopods, little changes in isopod abundance occurred during the following 24 h, and at the end of the experiment some individuals of all life history stages still remained in the holdfasts. These results indicate that all life history stages of Limnoria participate in both active migration and passive dispersal. It is discussed that storm-related dynamics within kelp forests may contribute to intense mixing of local populations of these burrow-dwelling isopods, and that most immigrants to young holdfasts probably are individuals emigrating from old holdfasts detached during storm events. The fact that some individuals of all life history stages and both sexes remain in floating

  11. Giant frequency-selective near-field energy transfer in active-passive structures

    NASA Astrophysics Data System (ADS)

    Khandekar, Chinmay; Jin, Weiliang; Miller, Owen D.; Pick, Adi; Rodriguez, Alejandro W.

    2016-09-01

    We apply a fluctuation electrodynamics framework in combination with semianalytical (dipolar) approximations to study amplified spontaneous energy transfer (ASET) between active and passive bodies. We consider near-field energy transfer between semi-infinite planar media and spherical structures (dimers and lattices) subject to gain, and show that the combination of loss compensation and near-field enhancement (achieved by the proximity, enhanced interactions, and tuning of subwavelength resonances) in these structures can result in orders of magnitude ASET enhancements below the lasing threshold. We examine various possible geometric configurations, including realistic materials, and describe optimal conditions for enhancing ASET, showing that the latter depends sensitively on both geometry and gain, enabling efficient and tunable gain-assisted energy extraction from structured surfaces.

  12. Snowfall estimation from space-borne active and passive microwave observations

    NASA Astrophysics Data System (ADS)

    Grecu, M.

    2006-12-01

    In this study, an algorithm to estimate snowfall from passive and active microwave observations is formulated and analyzed using both simulated and real observations. A high resolution cloud resolving model (CRM) is used to simulate a snowfall event and space-borne radar and radiometer observations similar to those of the future Global Precipitation Mission (GPM) are synthesized from the CRM data. Then a combined radar- radiometer similar to that of Grecu et al. (2004) is applied to the synthetic data. It is found that in spite of dual-frequency radar and millimeter-wave radiometer observations, snow retrievals from GPM-like observations are subject to various uncertainties. Simple parameterizations are devised to minimize these uncertainties. The combined radar-radiometer, modified to account for differences between the instruments deployed in Wakasa Bay Experiment and the GPM instruments, is applied to real data from the Wakasa Bay Experiment. Results show the algorithm's feasibility.

  13. Prevention of domino effect: from active and passive strategies to inherently safer design.

    PubMed

    Cozzani, Valerio; Tugnoli, Alessandro; Salzano, Ernesto

    2007-01-10

    The possible application of an inherent safety approach to the prevention of domino accidents was explored. The application of the inherent safety guidewords to the definition of effective actions for the prevention of domino events was analyzed. Due to the constraints originated by the conventional approach to process design, the "limitation of effects" guideword resulted the more effective in the identification of inherent safety actions to avoid domino events. Detailed design criteria for the improvement of layout in the framework of inherent safety were identified and discussed. Simple rules of thumbs were obtained for the preliminary assessment of safety distances and of critical inventories with respect to the escalation of fires and explosions. The results evidenced that the integration of inherent safety criteria with conventional passive or active protections seems a promising route for the prevention of severe domino accidental scenarios in chemical and process plants.

  14. Error Characterisation and Merging of Active and Passive Microwave Soil Moisture Data Sets

    NASA Astrophysics Data System (ADS)

    Wagner, Wolfgang; Gruber, Alexander; de Jeu, Richard; Parinussa, Robert; Chung, Daniel; Dorigo, Wouter; Reimer, Christoph; Kidd, Richard

    2015-04-01

    As part of the Climate Change Initiative (CCI) programme of the European Space Agency (ESA) a data fusion system has been developed which is capable of ingesting surface soil moisture data derived from active and passive microwave sensors (ASCAT, AMSR-E, etc.) flown on different satellite platforms and merging them to create long and consistent time series of soil moisture suitable for use in climate change studies. The so-created soil moisture data records (latest version: ESA CCI SM v02.1 released on 5/12/2014) are freely available and can be obtained from http://www.esa-soilmoisture-cci.org/. As described by Wagner et al. (2012) the principle steps of the data fusion process are: 1) error characterisation, 2) matching to account for data set specific biases, and 3) merging. In this presentation we present the current data fusion process and discuss how new error characterisation methods, such as the increasingly popular triple collocation method as discussed for example by Zwieback et al. (2012) may be used to improve it. The main benefit of an improved error characterisation would be a more reliable identification of the best performing microwave soil moisture retrieval(s) for each grid point and each point in time. In case that two or more satellite data sets provides useful information, the estimated errors can be used to define the weights with which each satellite data set are merged, i.e. the lower its error the higher its weight. This is expected to bring a significant improvement over the current data fusion scheme which is not yet based on quantitative estimates of the retrieval errors but on a proxy measure, namely the vegetation optical depth (Dorigo et al., 2015): over areas with low vegetation passive soil moisture retrievals are used, while over areas with moderate vegetation density active retrievals are used. In transition areas, where both products correlate well, both products are being used in a synergistic way: on time steps where only one of

  15. NASA's Potential Contributions to Avalanche Forecasting Using Active and Passive Microwave Measurements

    NASA Technical Reports Server (NTRS)

    Blonski, Slawomir

    2007-01-01

    This Candidate Solution is based on using active and passive microwave measurements acquired from NASA satellites to improve USDA (U.S. Department of Agriculture) Forest Service forecasting of avalanche danger. Regional Avalanche Centers prepare avalanche forecasts using ground measurements of snowpack and mountain weather conditions. In this Solution, range of the in situ observations is extended by adding remote sensing measurements of snow depth, snow water equivalent, and snowfall rate acquired by satellite missions that include Aqua, CloudSat, future GPM (Global Precipitation Measurement), and the proposed SCLP (Snow and Cold Land Processes). Measurements of snowpack conditions and time evolution are improved by combining the in situ and satellite observations with a snow model. Recurring snow observations from NASA satellites increase accuracy of avalanche forecasting, which helps the public and the managers of public facilities make better avalanche safety decisions.

  16. Studies of passive and active plasmonic core-shell nanoparticles and their applications

    NASA Astrophysics Data System (ADS)

    Campbell, Sawyer Duane

    Coated nanoparticles (CNP) are core-shell particles consisting of differing layers of epsilon positive (EP) and epsilon negative (ENG) materials. The juxtaposition of these EP and ENG materials can lead to the possibility of coupling incident plane waves to surface plasmon resonances (SPR) for particles even highly subwavelength in size. We introduce standard models of the permittivities of the noble metals used in these CNPs, and propose corrections to them based on experimental data when their sizes are extremely small. Mie theory is the solution to plane wave scattering by spheres and we extend the solution here to spheres consisting of an arbitrary number of layers. We discuss the resonance behaviors of passive CNPs with an emphasis on how the Coated nanoparticles (CNP) are core-shell particles consisting of differing layers of epsilon positive (EP) and epsilon negative (ENG) materials. The juxtaposition of these EP and ENG materials can lead to the possibility of coupling incident plane waves to surface plasmon resonances (SPR) for particles even highly subwavelength in size. We introduce standard models of the permittivities of the noble metals used in these CNPs, and propose corrections to them based on experimental data when their sizes are extremely small. Mie theory is the solution to plane wave scattering by spheres and we extend the solution here to spheres consisting of an arbitrary number of layers. We discuss the resonance behaviors of passive CNPs with an emphasis on how the resonance wavelength can be tuned by controlling the material properties and radii of the various layers in the configuration. It is demonstrated that these passive CNPs have scattering cross sections much larger than their geometrical size, but their resonance strengths are attenuated because of the inherent losses in the metals.To overcome this limitation, we show how the introduction of active material into the CNPs can not only overcome these losses, but can actually lead to

  17. Modelling Rift Valley fever (RVF) disease vector habitats using active and passive remote sensing systems

    NASA Technical Reports Server (NTRS)

    Ambrosia, Vincent G.; Linthicum, K. G.; Bailey, C. L.; Sebesta, P.

    1989-01-01

    The NASA Ames Ecosystem Science and Technology Branch and the U.S. Army Medical Research Institute of Infectious Diseases are conducting research to detect Rift Valley fever (RVF) vector habitats in eastern Africa using active and passive remote-sensing. The normalized difference vegetation index (NDVI) calculated from Landsat TM and SPOT data is used to characterize the vegetation common to the Aedes mosquito. Relationships have been found between the highest NDVI and the 'dambo' habitat areas near Riuru, Kenya on both wet and dry data. High NDVI values, when combined with the vegetation classifications, are clearly related to the areas of vector habitats. SAR data have been proposed for use during the rainy season when optical systems are of minimal use and the short frequency and duration of the optimum RVF mosquito habitat conditions necessitate rapid evaluation of the vegetation/moisture conditions; only then can disease potential be stemmed and eradication efforts initiated.

  18. Optimality of incompletely measurable active and passive attitude control systems. [for satellites

    NASA Technical Reports Server (NTRS)

    Schiehlen, W.; Popp, K.

    1973-01-01

    Passive attitude control systems and active systems with incomplete state measurements are only suboptimal systems in the sense of optimal control theory, since optimal systems require complete state measurements or state estimations. An optimal system, then, requires additional hardware (especially in the case of flexible spacecraft) which results in higher costs. Therefore, it is a real engineering problem to determine how much an optimal system exceeds the suboptimal system, or in other words, what is the suboptimal system's degree of optimality. The problem will be treated in three steps: (1) definition of the degree of optimality for linear, time-invariant systems; (2) a computation method using the quadratic cost functional; (3) application to a gravity-gradient stabilized three-body satellite and a spinning flexible satellite.

  19. In-plant experience with passive-active shufflers at Los Alamos

    SciTech Connect

    Hurd, J.R.; Hsue, F.; Rinard, P.M.

    1995-09-01

    Two Canberra-built passive-active {sup 252}Cf shufflers of Los Alamos hardware and software design have been installed at Los Alamos National Laboratory, one at the Chemistry and Metallurgy Research (CMR) Facility at TA-3 and the other at the Plutonium Facility (PF-4) at TA-55. These instruments fulfill important safeguards and accountability measurement requirements for special nuclear material (SNM) in matrices too dense or otherwise not appropriate for typical gamma-ray or other neutron counting techniques. They support many programmatic requirements including measurements of transuranic (TRU) waste and inventory verification. This paper describes the instrument performance under plant conditions with various background radiations on well-characterized standards to determine long-term stability and establish a calibration. Results are also reported on verification measurements of previously unmeasured inventory items in various matrices and geometric distributions. Preliminary investigative measurements are presented on standards of mixed uranium and plutonium oxide (MOX).

  20. Estimation of passive and active properties in the human heart using 3D tagged MRI.

    PubMed

    Asner, Liya; Hadjicharalambous, Myrianthi; Chabiniok, Radomir; Peresutti, Devis; Sammut, Eva; Wong, James; Carr-White, Gerald; Chowienczyk, Philip; Lee, Jack; King, Andrew; Smith, Nicolas; Razavi, Reza; Nordsletten, David

    2016-10-01

    Advances in medical imaging and image processing are paving the way for personalised cardiac biomechanical modelling. Models provide the capacity to relate kinematics to dynamics and-through patient-specific modelling-derived material parameters to underlying cardiac muscle pathologies. However, for clinical utility to be achieved, model-based analyses mandate robust model selection and parameterisation. In this paper, we introduce a patient-specific biomechanical model for the left ventricle aiming to balance model fidelity with parameter identifiability. Using non-invasive data and common clinical surrogates, we illustrate unique identifiability of passive and active parameters over the full cardiac cycle. Identifiability and accuracy of the estimates in the presence of controlled noise are verified with a number of in silico datasets. Unique parametrisation is then obtained for three datasets acquired in vivo. The model predictions show good agreement with the data extracted from the images providing a pipeline for personalised biomechanical analysis.