Neural Correlates of Skill Acquisition: Decreased Cortical Activity During a Serial Interception Sequence Learning Task

PubMed Central

Gobel, Eric W.; Parrish, Todd B.; Reber, Paul J.

2011-01-01

Learning of complex motor skills requires learning of component movements as well as the sequential structure of their order and timing. Using a Serial Interception Sequence Learning (SISL) task, participants learned a sequence of precisely timed interception responses through training with a repeating sequence. Following initial implicit learning of the repeating sequence, functional MRI data were collected during performance of that known sequence and compared with activity evoked during novel sequences of actions, novel timing patterns, or both. Reduced activity was observed during the practiced sequence in a distributed bilateral network including extrastriate occipital, parietal, and premotor cortical regions. These reductions in evoked activity likely reflect improved efficiency in visuospatial processing, spatio-motor integration, motor planning, and motor execution for the trained sequence, which is likely supported by nondeclarative skill learning. In addition, the practiced sequence evoked increased activity in the left ventral striatum and medial prefrontal cortex, while the posterior cingulate was more active during periods of better performance. Many prior studies of perceptual-motor skill learning have found increased activity in motor areas of frontal cortex (e.g., motor and premotor cortex, SMA) and striatal areas (e.g., the putamen). The change in activity observed here (i.e., decreased activity across a cortical network) may reflect skill learning that is predominantly expressed through more accurate performance rather than decreased reaction time. PMID:21771663

Neural correlates of skill acquisition: decreased cortical activity during a serial interception sequence learning task.

PubMed

Gobel, Eric W; Parrish, Todd B; Reber, Paul J

2011-10-15

Learning of complex motor skills requires learning of component movements as well as the sequential structure of their order and timing. Using a Serial Interception Sequence Learning (SISL) task, participants learned a sequence of precisely timed interception responses through training with a repeating sequence. Following initial implicit learning of the repeating sequence, functional MRI data were collected during performance of that known sequence and compared with activity evoked during novel sequences of actions, novel timing patterns, or both. Reduced activity was observed during the practiced sequence in a distributed bilateral network including extrastriate occipital, parietal, and premotor cortical regions. These reductions in evoked activity likely reflect improved efficiency in visuospatial processing, spatio-motor integration, motor planning, and motor execution for the trained sequence, which is likely supported by nondeclarative skill learning. In addition, the practiced sequence evoked increased activity in the left ventral striatum and medial prefrontal cortex, while the posterior cingulate was more active during periods of better performance. Many prior studies of perceptual-motor skill learning have found increased activity in motor areas of the frontal cortex (e.g., motor and premotor cortex, SMA) and striatal areas (e.g., the putamen). The change in activity observed here (i.e., decreased activity across a cortical network) may reflect skill learning that is predominantly expressed through more accurate performance rather than decreased reaction time. Copyright © 2011 Elsevier Inc. All rights reserved.

Eye movement accuracy determines natural interception strategies.

PubMed

Fooken, Jolande; Yeo, Sang-Hoon; Pai, Dinesh K; Spering, Miriam

2016-11-01

Eye movements aid visual perception and guide actions such as reaching or grasping. Most previous work on eye-hand coordination has focused on saccadic eye movements. Here we show that smooth pursuit eye movement accuracy strongly predicts both interception accuracy and the strategy used to intercept a moving object. We developed a naturalistic task in which participants (n = 42 varsity baseball players) intercepted a moving dot (a "2D fly ball") with their index finger in a designated "hit zone." Participants were instructed to track the ball with their eyes, but were only shown its initial launch (100-300 ms). Better smooth pursuit resulted in more accurate interceptions and determined the strategy used for interception, i.e., whether interception was early or late in the hit zone. Even though early and late interceptors showed equally accurate interceptions, they may have relied on distinct tactics: early interceptors used cognitive heuristics, whereas late interceptors' performance was best predicted by pursuit accuracy. Late interception may be beneficial in real-world tasks as it provides more time for decision and adjustment. Supporting this view, baseball players who were more senior were more likely to be late interceptors. Our findings suggest that interception strategies are optimally adapted to the proficiency of the pursuit system.

The chemical composition of fogs and intercepted clouds in the United States

NASA Astrophysics Data System (ADS)

Collett, Jeffrey L.; Bator, Aaron; Sherman, D. Eli; Moore, Katharine F.; Hoag, Katherine J.; Demoz, Belay B.; Rao, Xin; Reilly, Jill E.

Over the past decade, the chemical compositions of fogs and intercepted clouds have been investigated at more than a dozen locations across the United States. Sampling sites have been located in the northeast, southeast, Rocky Mountain, and west coast regions of the US. They include both pristine and heavily polluted locations. Frontal/orographic clouds (warm and supercooled), intercepted coastal stratiform clouds, and radiation fogs have all been examined. Sample pH values range from below 3 to above 7. Major ions also exhibit a wide concentration range, with clouds at some locations exhibiting high sea salt concentrations, while composition at other locations is dominated by ammonium and sulfate or nitrate.

Optimal Interception of a Maneuvering Long-range Missile

NASA Astrophysics Data System (ADS)

X. Vinh, Nguyen; T. Kabamba, Pierre; Takehira, Tetsuya

2001-01-01

In a Newtonian central force field, the minimum-fuel interception of a satellite, or a ballistic missile, in elliptic trajectory can be obtained via Lawden's theory of primer vector. To secure interception when the target performs evasive maneuvers, a new control law, with explicit solutions, is implemented. It is shown that by a rotation of coordinate system, the problem of three-dimensional interception is reduced to a planar problem. The general case of planar interception of a long-range ballistic missile is then studied. Examples of interception at a specified time, head-on interception and minimum-fuel interception are presented. In each case, the requirement for the thrust acceleration is expressed explicitly as a function of time.

Interception loss, throughfall and stemflow in a maritime pine stand. II. An application of Gash's analytical model of interception

NASA Astrophysics Data System (ADS)

Loustau, D.; Berbigier, P.; Granier, A.

1992-10-01

Interception, throughfall and stemflow were determined in an 18-year-old maritime pine stand for a period of 30 months. This involved 71 rainfall events, each corresponding either to a single storm or to several storms. Gash's analytical model of interception was used to estimate the sensitivity of interception to canopy structure and climatic parameters. The seasonal cumulative interception loss corresponded to 12.6-21.0% of the amount of rainfall, whereas throughfall and stemflow accounted for 77-83% and 1-6%, respectively. On a seasonal basis, simulated data fitted the measured data satisfactorily ( r2 = 0.75). The rainfall partitioning between interception, throughfall and stemflow was shown to be sensitive to (1) the rainfall regime, i.e. the relative importance of light storms to total rainfall, (2) the climatic parameters, rainfall rate and average evaporation rate during storms, and (3) the canopy structure parameters of the model. The low interception rate of the canopy was attributed primarily to the low leaf area index of the stand.

Estimation of air-to-grass mass interception factors for iodine.

PubMed

Karunakara, N; Ujwal, P; Yashodhara, I; Sudeep Kumara, K; Mohan, M P; Bhaskar Shenoy, K; Geetha, P V; Dileep, B N; James, Joshi P; Ravi, P M

2018-06-01

Air-to-grass mass interception factors for radionuclide are important basic input parameter for the estimation of radiation dose to the public around a nuclear power plant. In this paper, we present the determination of air-to- grass mass interception factors for iodine using a 2 m × 2 m × 2 m (l × b × h) size environmental chamber. The temperature, humidity, and rainfall inside the environmental chamber was controlled to required values to simulate different environmental conditions. Grass (Pennisetum purpureum, Schum), grown in pots, was kept inside the environmental chamber and stable iodine in elemental form was sublimed quickly inside the chamber to simulate an accidental release of iodine to the environment. The concentration of iodine in the air was measured periodically by drawing air through a bubbling setup, containing 1% sodium carbonate solution. The mass interception factor for dry deposition varied in the range of 0.25-7.7 m 2  kg -1 with mean value of 2.2 m 2  kg -1 with respect to fresh weight of grass, and that due to wet deposition varied in the range of 0.6-4.8 m 2  kg -1 with mean value of 2.3 m 2  kg -1 . The mass interception factor was inversely correlated with the total iodine deposited through dry deposition as well as with the rainfall. Copyright © 2017. Published by Elsevier Ltd.

Fog interception by Ball moss (Tillandsia recurvata)

NASA Astrophysics Data System (ADS)

Guevara-Escobar, A.; Cervantes-Jiménez, M.; Suzán-Azpiri, H.; González-Sosa, E.; Hernández-Sandoval, L.; Malda-Barrera, G.; Martínez-Díaz, M.

2011-08-01

Interception losses are a major influence in the water yield of vegetated areas. For most storms, rain interception results in less water reaching the ground. However, fog interception can increase the overall water storage capacity of the vegetation and once the storage is exceeded, fog drip is a common hydrological input. Fog interception is disregarded in water budgets of semiarid regions, but for some plant communities, it could be a mechanism offsetting evaporation losses. Tillandsia recurvata is a cosmopolitan epiphyte adapted to arid habitats where fog may be an important water source. Therefore, the interception storage capacity by T. recurvata was measured in controlled conditions and applying simulated rain or fog. Juvenile, vegetative specimens were used to determine the potential upperbound storage capacities. The storage capacity was proportional to dry weight mass. Interception storage capacity (Cmin) was 0.19 and 0.56 mm for rainfall and fog respectively. The coefficients obtained in the laboratory were used together with biomass measurements for T. recurvata in a xeric scrub to calculate the depth of water intercepted by rain. T. recurvata contributed 20 % to the rain interception capacity of their shrub hosts: Acacia farnesiana and Prosopis laevigata and; also potentially intercepted 4.8 % of the annual rainfall. Nocturnal stomatic opening in T. recurvata is not only relevant for CO2 but for water vapor, as suggested by the higher weight change of specimens wetted with fog for 1 h at dark in comparison to those wetted during daylight (543 ± 77 vs. 325 ± 56 mg, p = 0.048). The storage capacity of T. recurvata leaf surfaces could increase the amount of water available for evaporation, but as this species colonise montane forests, the effect could be negative on water recharge, because potential storage capacity is very high, in the laboratory experiments it took up to 12 h at a rate of 0.26 l h-1 to reach saturation conditions when fog was applied.

Global canopy interception from satellite observations

USDA-ARS?s Scientific Manuscript database

A new methodology for retrieving rainfall interception rates from multi satellite observations is presented. The approach makes use of the daily productof the Global Precipitation Climatology Project (GPCP) as driving data and applies Gash’s analytical model to derive interception rates at global sc...

Constrained orbital intercept-evasion

NASA Astrophysics Data System (ADS)

Zatezalo, Aleksandar; Stipanovic, Dusan M.; Mehra, Raman K.; Pham, Khanh

2014-06-01

An effective characterization of intercept-evasion confrontations in various space environments and a derivation of corresponding solutions considering a variety of real-world constraints are daunting theoretical and practical challenges. Current and future space-based platforms have to simultaneously operate as components of satellite formations and/or systems and at the same time, have a capability to evade potential collisions with other maneuver constrained space objects. In this article, we formulate and numerically approximate solutions of a Low Earth Orbit (LEO) intercept-maneuver problem in terms of game-theoretic capture-evasion guaranteed strategies. The space intercept-evasion approach is based on Liapunov methodology that has been successfully implemented in a number of air and ground based multi-player multi-goal game/control applications. The corresponding numerical algorithms are derived using computationally efficient and orbital propagator independent methods that are previously developed for Space Situational Awareness (SSA). This game theoretical but at the same time robust and practical approach is demonstrated on a realistic LEO scenario using existing Two Line Element (TLE) sets and Simplified General Perturbation-4 (SGP-4) propagator.

Composition-dependence of stacking fault energy in austenitic stainless steels through linear regression with random intercepts

NASA Astrophysics Data System (ADS)

Meric de Bellefon, G.; van Duysen, J. C.; Sridharan, K.

2017-08-01

The stacking fault energy (SFE) plays an important role in deformation behavior and radiation damage of FCC metals and alloys such as austenitic stainless steels. In the present communication, existing expressions to calculate SFE in those steels from chemical composition are reviewed and an improved multivariate linear regression with random intercepts is used to analyze a new database of 144 SFE measurements collected from 30 literature references. It is shown that the use of random intercepts can account for experimental biases in these literature references. A new expression to predict SFE from austenitic stainless steel compositions is proposed.

The combined effect of platelet storage media and intercept pathogen reduction technology on platelet activation/activability and cellular apoptosis/necrosis: Lisbon-RBS experience.

PubMed

Carvalho, Helena; Alguero, Carmen; Santos, Matilde; de Sousa, Gracinda; Trindade, Helder; Seghatchian, Jerard

2006-04-01

Platelets are known to undergo shape change, activation, a release reaction and apoptosis/necrosis during processing and storage, all of which are collectively known as the platelet storage lesion. Any additional processing may have some deleterious impact on platelet activability and functional integrity, which need to be investigated. This preliminary investigation was undertaken to establish the combined effects of standard platelet storage media and the intercept pathogen reduction technology on platelet activation and activability during 7 day storage, using buffy-coat derived platelets in standard storage media containing 35% plasma (N=24). P-selectin (CD62p) expression, a classical marker of platelet activation, and phosphatidylserine (PS) exposure on the platelet surface membrane, a hallmark of cellular necrosis/apoptosis, were both measured by flow cytometry. The results reveal significant increases in activation, from an average of 22.7% on day 1 before treatment to 31.6% on day 2 after treatment and 58.7% at the end of storage. Concomitantly, the basal expression of PS was slightly increased from 1.9% to 2.8% at day 2 after treatment and 7.3% at the end of storage. However, the functional reserve of platelets during storage, which reflects their capability to undergo activation and the release reaction when platelets were challenged with either calcium ionophore or thrombin, was relatively well maintained. These preliminary data confirm the earlier data on the use of intercept, and for the first time, based on the assessment of platelet functional integrity, suggest that platelet functional reserve is relatively well maintained, with little change in the formation of apoptotic cells.

Indirect interception actions by blind and visually impaired perceivers: echolocation for interceptive actions.

PubMed

Vernat, Jean-Philippe; Gordon, Michael S

2010-02-01

This research examined the acoustic information used to support interceptive actions by the blind. Congenitally blind and severely visually impaired participants (all wearing an opaque, black eye-mask) were asked to listen to a target ball rolling down a track. In response, participants rolled their own ball along a perpendicular path to intercept the target. To better understand what information was used the echoic conditions and rolling dynamics of the target were varied across test sessions. In addition the rolling speed of the target and the distance of the participant from the target were varied across trials. Results demonstrated that participants tended to perform most accurately at moderate speeds and distances, overestimating the target's arrival at the fastest speed, and underestimating it at the slowest speed. However, changes to the target's dynamics, that is, the amount of deceleration it underwent on approach, did not strongly influence performance. Echoic conditions were found to affect performance, as participants were slightly more accurate in conditions with faster, higher-intensity echoes. Based on these results blind individuals in this research seemed to be using spatial and temporal cues to coordinate their interceptive actions.

Interception of precipitation by northern hardwoods

Treesearch

Raymond E. Leonard

1961-01-01

When forest watershed management research was begun at the Hubbard Brook Experimental Forest in the White Mountains of New Hampshire in 1955, we felt certain that at least one aspect of hydrology would not require study-interception. Interception has been studied for a long time, in fact, as early as 1889 (Horton, 1919). It has been well known that a certain amount of...

Using a simple apparatus to measure direct and diffuse photosynthetically active radiation at remote locations.

PubMed

Cruse, Michael J; Kucharik, Christopher J; Norman, John M

2015-01-01

Plant canopy interception of photosynthetically active radiation (PAR) drives carbon dioxide (CO2), water and energy cycling in the soil-plant-atmosphere system. Quantifying intercepted PAR requires accurate measurements of total incident PAR above canopies and direct beam and diffuse PAR components. While some regional data sets include these data, e.g. from Atmospheric Radiation Measurement (ARM) Program sites, they are not often applicable to local research sites because of the variable nature (spatial and temporal) of environmental variables that influence incoming PAR. Currently available instrumentation that measures diffuse and direct beam radiation separately can be cost prohibitive and require frequent adjustments. Alternatively, generalized empirical relationships that relate atmospheric variables and radiation components can be used but require assumptions that increase the potential for error. Our goal here was to construct and test a cheaper, highly portable instrument alternative that could be used at remote field sites to measure total, diffuse and direct beam PAR for extended time periods without supervision. The apparatus tested here uses a fabricated, solar powered rotating shadowband and other commercially available parts to collect continuous hourly PAR data. Measurements of total incident PAR had nearly a one-to-one relationship with total incident radiation measurements taken at the same research site by an unobstructed point quantum sensor. Additionally, measurements of diffuse PAR compared favorably with modeled estimates from previously published data, but displayed significant differences that were attributed to the important influence of rapidly changing local environmental conditions. The cost of the system is about 50% less than comparable commercially available systems that require periodic, but not continual adjustments. Overall, the data produced using this apparatus indicates that this instrumentation has the potential to support

Using a Simple Apparatus to Measure Direct and Diffuse Photosynthetically Active Radiation at Remote Locations

PubMed Central

Cruse, Michael J.; Kucharik, Christopher J.; Norman, John M.

2015-01-01

Plant canopy interception of photosynthetically active radiation (PAR) drives carbon dioxide (CO2), water and energy cycling in the soil-plant-atmosphere system. Quantifying intercepted PAR requires accurate measurements of total incident PAR above canopies and direct beam and diffuse PAR components. While some regional data sets include these data, e.g. from Atmospheric Radiation Measurement (ARM) Program sites, they are not often applicable to local research sites because of the variable nature (spatial and temporal) of environmental variables that influence incoming PAR. Currently available instrumentation that measures diffuse and direct beam radiation separately can be cost prohibitive and require frequent adjustments. Alternatively, generalized empirical relationships that relate atmospheric variables and radiation components can be used but require assumptions that increase the potential for error. Our goal here was to construct and test a cheaper, highly portable instrument alternative that could be used at remote field sites to measure total, diffuse and direct beam PAR for extended time periods without supervision. The apparatus tested here uses a fabricated, solar powered rotating shadowband and other commercially available parts to collect continuous hourly PAR data. Measurements of total incident PAR had nearly a one-to-one relationship with total incident radiation measurements taken at the same research site by an unobstructed point quantum sensor. Additionally, measurements of diffuse PAR compared favorably with modeled estimates from previously published data, but displayed significant differences that were attributed to the important influence of rapidly changing local environmental conditions. The cost of the system is about 50% less than comparable commercially available systems that require periodic, but not continual adjustments. Overall, the data produced using this apparatus indicates that this instrumentation has the potential to support

Quadrotor Intercept Trajectory Planning and Simulation

DTIC Science & Technology

2017-06-01

Figure 41. Results are grouped by geometry type and colored based on trajectory planner. Figure 41. Summary of Experimental Data Intercept Time...DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words) Quadrotor drones pose a safety hazard when operated in or near controlled airspace. A hazardous...quadrotor could be intercepted and removed by another quadrotor. In this thesis, we seek to determine if optimal control methods outperform missile

Influence of rainfall microstructure on rainfall interception

NASA Astrophysics Data System (ADS)

Zabret, Katarina; Rakovec, Jože; Mikoš, Matjaž; Šraj, Mojca

2016-04-01

Rainfall interception is part of the hydrological cycle. Precipitation, which hits vegetation, is retained on the leaves and branches, from which it eventually evaporates into the atmosphere (interception) or reaches the ground by dripping from the canopy, falling through the gaps (throughfall) and running down the stems (stemflow). The process is influenced by various meteorological and vegetation parameters. Often neglected meteorological parameter influencing rainfall interception is also rainfall microstructure. Rain is a discrete process consisting of various numbers of individual raindrops with different sizes and velocities. This properties describe rainfall microstructure which is often neglected in hydrological analysis and replaced with rainfall intensity. Throughfall, stemflow and rainfall microstructure have been measured since the beginning of the year 2014 under two tree species (Betula pendula and Pinus nigra) on a study plot in Ljubljana, Slovenia. The preliminary analysis of the influence of rainfall microstructure on rainfall interception has been conducted using three events with different characteristics measured in May 2014. Event A is quite short with low rainfall amount and moderate rainfall intensity, whereas events B and C have similar length but low and high intensities, respectively. Event A was observed on the 1st of May 2014. It was 22 minutes long and delivered 1.2 mm of rainfall. The average rainfall intensity was equal to 3.27 mm/h. The event consisted of 1,350 rain drops with average diameter of 1.517 mm and average velocity of 5.110 m/s. Both Betula pendula and Pinus nigra intercepted similar amount of rainfall, 68 % and 69 %, respectively. Event B was observed in the night from the 7th to 8th of May 2014, it was 16 hours and 18 minutes long, and delivered 4.2 mm of rainfall with average intensity of 0.97 mm/h. There were 39,108 raindrops detected with average diameter of 0.858 mm and average velocity of 3.855 m/s. Betula pendula

Fitting rainfall interception models to forest ecosystems of Mexico

NASA Astrophysics Data System (ADS)

Návar, José

2017-05-01

Models that accurately predict forest interception are essential both for water balance studies and for assessing watershed responses to changes in land use and the long-term climate variability. This paper compares the performance of four rainfall interception models-the sparse Gash (1995), Rutter et al. (1975), Liu (1997) and two new models (NvMxa and NvMxb)-using data from four spatially extensive, structurally diverse forest ecosystems in Mexico. Ninety-eight case studies measuring interception in tropical dry (25), arid/semi-arid (29), temperate (26), and tropical montane cloud forests (18) were compiled and analyzed. Coefficients derived from raw data or published statistical relationships were used as model input to evaluate multi-storm forest interception at the case study scale. On average empirical data showed that, tropical montane cloud, temperate, arid/semi-arid and tropical dry forests intercepted 14%, 18%, 22% and 26% of total precipitation, respectively. The models performed well in predicting interception, with mean deviations between measured and modeled interception as a function of total precipitation (ME) generally <5.8% and Nash-Sutcliffe efficiency E estimators >0.66. Model fitting precision was dependent on the forest ecosystem. Arid/semi-arid forests exhibited the smallest, while tropical montane cloud forest displayed the largest ME deviations. Improved agreement between measured and modeled data requires modification of in-storm evaporation rate in the Liu; the canopy storage in the sparse Gash model; and the throughfall coefficient in the Rutter and the NvMx models. This research concludes on recommending the wide application of rainfall interception models with some caution as they provide mixed results. The extensive forest interception data source, the fitting and testing of four models, the introduction of a new model, and the availability of coefficient values for all four forest ecosystems are an important source of information and

Estimation of Stormwater Interception Rate for various LID Facilities

NASA Astrophysics Data System (ADS)

Kim, S.; Lee, O.; Choi, J.

2017-12-01

In this study, the stormwater interception rate is proposed to apply in the design of LID facilities. For this purpose, EPA-SWMM is built with some areas of Noksan National Industrial Complex where long-term observed stormwater data were monitored and stormwater interception rates for various design capacities of various LID facilities are estimated. While the sensitivity of stormwater interception rate according to design specifications of bio-retention and infiltration trench facilities is not large, the sensitivity of stormwater interception rate according to local rainfall characteristics is relatively big. As a result of comparing the present rainfall interception rate estimation method which is officially operated in Korea with the one proposed in this study, it will be presented that the present method is highly likely to overestimate the performance of the bio-retention and infiltration trench facilities. Finally, a new stormwater interception rate formulas for the bio-retention and infiltration trench LID facilities will be proposed. Acknowledgement This research was supported by a grant (2016000200002) from Public Welfare Technology Development Program funded by Ministry of Environment of Korean government.

Does the intercept of the heat-stress relation provide an accurate estimate of cardiac activation heat?

PubMed

Pham, Toan; Tran, Kenneth; Mellor, Kimberley M; Hickey, Anthony; Power, Amelia; Ward, Marie-Louise; Taberner, Andrew; Han, June-Chiew; Loiselle, Denis

2017-07-15

The heat of activation of cardiac muscle reflects the metabolic cost of restoring ionic homeostasis following a contraction. The accuracy of its measurement depends critically on the abolition of crossbridge cycling. We abolished crossbridge activity in isolated rat ventricular trabeculae by use of blebbistatin, an agent that selectively inhibits myosin II ATPase. We found cardiac activation heat to be muscle length independent and to account for 15-20% of total heat production at body temperature. We conclude that it can be accurately estimated at minimal muscle length. Activation heat arises from two sources during the contraction of striated muscle. It reflects the metabolic expenditure associated with Ca 2+ pumping by the sarcoplasmic reticular Ca 2+ -ATPase and Ca 2+ translocation by the Na + /Ca 2+ exchanger coupled to the Na + ,K + -ATPase. In cardiac preparations, investigators are constrained in estimating its magnitude by reducing muscle length to the point where macroscopic twitch force vanishes. But this experimental protocol has been criticised since, at zero force, the observed heat may be contaminated by residual crossbridge cycling activity. To eliminate this concern, the putative thermal contribution from crossbridge cycling activity must be abolished, at least at minimal muscle length. We achieved this using blebbistatin, a selective inhibitor of myosin II ATPase. Using a microcalorimeter, we measured the force production and heat output, as functions of muscle length, of isolated rat trabeculae from both ventricles contracting isometrically at 5 Hz and at 37°C. In the presence of blebbistatin (15 μmol l -1 ), active force was zero but heat output remained constant, at all muscle lengths. Activation heat measured in the presence of blebbistatin was not different from that estimated from the intercept of the heat-stress relation in its absence. We thus reached two conclusions. First, activation heat is independent of muscle length. Second

Transport of intercepted snow from trees during snow storms

Treesearch

David H. Miller

1966-01-01

Five principal processes by which intercepted snow in trees is removed during snow storms are described and evaluated as far as data permit: vapor flux from melt water, vapor flux from bodies of snow, stem flow and dripping of melt water, sliding of bodies of intercepted snow from branches, and wind erosion and transport of intercepted snow. Further research is...

Rainfall interception by tree crown and leaf litter: an interactive process

Treesearch

Xiang Li; Qingfu Xiao; Jianzhi Niu; Salli Dymond; E. Gregory McPherson; Natalie van Doorn; Xinxiao Yu; Baoyuan Xie; Kebin Zhang; Jiao Li

2017-01-01

Rainfall interception research in forest ecosystems usually focuses on interception by either tree crown or leaf litter, although the 2 components interact when rainfall occurs. A process-based study was conducted to jointly measure rainfall interception by crown and litter and the interaction between the 2 interception processes for 4 tree species (...

A reprogrammable receiver architecture for wireless signal interception

NASA Astrophysics Data System (ADS)

Yao, Timothy S.

2003-09-01

In this paper, a re-programmable receiver architecture, based on software-defined-radio concept, for wireless signal interception is presented. The radio-frequency (RF) signal that the receiver would like to intercept may come from a terrestrial cellular network or communication satellites, which their carrier frequency are in the range from 800 MHz (civilian mobile) to 15 GHz (Ku band). To intercept signals from such a wide range of frequency in these variant communication systems, the traditional way is to deploy multiple receivers to scan and detect the desired signal. This traditional approach is obviously unattractive due to the cost, efficiency, and accuracy. Instead, we propose a universal receiver, which is software-driven and re-configurable, to intercept signals of interest. The software-defined-radio based receiver first intercepts RF energy of wide spectrum (25MHz) through antenna, performs zero-IF down conversion (homodyne architecture) to baseband, and digital channelizes the baseband signal. The channelization module is a bank of high performance digital filters. The bandwidth of the filter bank is programmable according to the wireless communication protocol under watch. In the baseband processing, high-performance digital signal processors carry out the detection process and microprocessors handle the communication protocols. The baseband processing is also re-configurable for different wireless standards and protocol. The advantages of the software-defined-radio architecture over traditional RF receiver make it a favorable technology for the communication signal interception and surveillance.

Contrasting roles of interception and transpiration in the hydrological cycle - Part 2: Moisture recycling

NASA Astrophysics Data System (ADS)

van der Ent, R. J.; Wang-Erlandsson, L.; Keys, P. W.; Savenije, H. H. G.

2014-03-01

The contribution of land evaporation to local and remote precipitation (i.e., moisture recycling) is of significant importance to sustain water resources and ecosystems. But how important are different evaporation components in sustaining precipitation? This is the first paper to present moisture recycling metrics for partitioned evaporation. In the companion paper, Part 1, evaporation was partitioned into vegetation interception, floor interception, soil moisture evaporation and open water evaporation (constituting the direct, purely physical fluxes, largely dominated by interception), and transpiration (delayed, biophysical flux). Here, we track these components forward as well as backward in time. We also include age tracers to study the atmospheric residence times of these evaporation components. As the main result we present a new image of the global hydrological cycle that includes quantification of partitioned evaporation and moisture recycling as well as the atmospheric residence times of all fluxes. We demonstrate that evaporated interception is more likely to return as precipitation on land than transpired water. On average, direct evaporation (essentially interception) is found to have an atmospheric residence time of eight days, while transpiration typically resides nine days in the atmosphere. Interception recycling has a much shorter local length scale than transpiration recycling, thus interception generally precipitates closer to its evaporative source than transpiration, which is particularly pronounced outside the tropics. We conclude that interception mainly works as an intensifier of the local hydrological cycle during wet spells. On the other hand, transpiration remains active during dry spells and is transported over much larger distances downwind where it can act as a significant source of moisture. Thus, as various land-use types can differ considerably in their partitioning between interception and transpiration, our results stress that

Ballistic intercept missions to Comet Encke

NASA Technical Reports Server (NTRS)

Mumma, M. (Compiler)

1975-01-01

The optimum ballistic intercept of a spacecraft with the comet Encke is determined. The following factors are considered in the analysis: energy requirements, encounter conditions, targeting error, comet activity, spacecraft engineering requirements and restraints, communications, and scientific return of the mission. A baseline model is formulated which includes the basic elements necessary to estimate the scientific return for the different missions considered. Tradeoffs which have major impact on the cost and/or scientific return of a ballistic mission to comet Encke are identified and discussed. Recommendations are included.

Interception of LPI radar signals

NASA Astrophysics Data System (ADS)

Lee, Jim P.

1991-11-01

Most current radars are designed to transmit short duration pulses with relatively high peak power. These radars can be detected easily by the use of relatively modest EW intercept receivers. Three radar functions (search, anti-ship missile (ASM) seeker, and navigation) are examined to evaluate the effectiveness of potential low probability of intercept (LPI) techniques, such as waveform coding, antenna profile control, and power management that a radar may employ against current Electronic Warfare (EW) receivers. The general conclusion is that it is possible to design a LPI radar which is effective against current intercept EW receivers. LPI operation is most easily achieved at close ranges and against a target with a large radar cross section. The general system sensitivity requirement for the detection of current and projected LPI radars is found to be on the order of -100 dBmi which cannot be met by current EW receivers. Finally, three potential LPI receiver architectures, using channelized, superhet, and acousto-optic receivers with narrow RF and video bandwidths are discussed. They have shown some potential in terms of providing the sensitivity and capability in an environment where both conventional and LPI signals are present.

How is rainfall interception in urban area affected by meteorological parameters?

NASA Astrophysics Data System (ADS)

Zabret, Katarina; Rakovec, Jože; Mikoš, Matjaž; Šraj, Mojca

2017-04-01

Rainfall interception is part of the hydrological cycle. Precipitation, which hits vegetation, is retained on the leaves and branches, from which it eventually evaporates into the atmosphere (interception) or reaches the ground by dripping from the canopy, falling through the gaps (throughfall) and running down the stems (stemflow). The amount of rainfall reaching the ground depends on various meteorological and vegetation parameters. Rainfall, throughfall and stemflow have been measured in the city of Ljubljana, Slovenia since the beginning of 2014. Manual and automatic measurements are performed regularly under Betula pendula and Pinus nigra trees in urban area. In 2014, there were detected 178 rainfall events with total amount of 1672.1 mm. In average B. pendula intercepted 44% of rainfall and P. nigra intercepted 72% of rainfall. In 2015 we have detected 117 events with 1047.4 mm of rainfall, of which 37% was intercepted by B. pendula and 60% by P. nigra. The effect of various meteorological parameters on the rainfall interception was analysed in the study. The parameters included in the analysis were rainfall rate, rainfall duration, drop size distribution (average drop velocity and diameter), average wind speed, and average temperature. The results demonstrate decreasing rainfall interception with longer rainfall duration and higher rainfall intensity although the impact of the latter one is not statistically significant. In the case of very fast or very slow rainfall drops, the interception is higher than for the mean rain drop velocity values. In the case of P. nigra the impact of the rain drop diameter on interception is similar to the one of rain drop velocity while for B. pendula increasing of drop diameter also increases the interception. As expected, interception is higher for warmer events. This trend is more evident for P. nigra than for B. pendula. Furthermore, the amount of intercepted rainfall also increases with wind although it could be

Rainfall interception of three trees in Oakland, California

Treesearch

Qingfu Xiao; E. Gregory McPherson

2011-01-01

A rainfall interception study was conducted in Oakland, California to determine the partitioning of rainfall and the chemical composition of precipitation, throughfall, and stemflow. Rainfall interception measurements were conducted on a gingko (Ginkgo biloba) (13.5 m tall deciduous tree), sweet gum (Liquidambar styraciflua) (8...

Point Intercept (PO)

Treesearch

John F. Caratti

2006-01-01

The FIREMON Point Intercept (PO) method is used to assess changes in plant species cover or ground cover for a macroplot. This method uses a narrow diameter sampling pole or sampling pins, placed at systematic intervals along line transects to sample within plot variation and quantify statistically valid changes in plant species cover and height over time. Plant...

Line Intercept (LI)

Treesearch

John F. Caratti

2006-01-01

The FIREMON Line Intercept (LI) method is used to assess changes in plant species cover for a macroplot. This method uses multiple line transects to sample within plot variation and quantify statistically valid changes in plant species cover and height over time. This method is suited for most forest and rangeland communities, but is especially useful for sampling...

Intercepting a moving target: On-line or model-based control?

PubMed

Zhao, Huaiyong; Warren, William H

2017-05-01

When walking to intercept a moving target, people take an interception path that appears to anticipate the target's trajectory. According to the constant bearing strategy, the observer holds the bearing direction of the target constant based on current visual information, consistent with on-line control. Alternatively, the interception path might be based on an internal model of the target's motion, known as model-based control. To investigate these two accounts, participants walked to intercept a moving target in a virtual environment. We degraded the target's visibility by blurring the target to varying degrees in the midst of a trial, in order to influence its perceived speed and position. Reduced levels of visibility progressively impaired interception accuracy and precision; total occlusion impaired performance most and yielded nonadaptive heading adjustments. Thus, performance strongly depended on current visual information and deteriorated qualitatively when it was withdrawn. The results imply that locomotor interception is normally guided by current information rather than an internal model of target motion, consistent with on-line control.

[Canopy interception characteristics of main vegetation types in Liupan Mountains of China].

PubMed

Xu, Li-hong; Shi, Zhong-jie; Wang, Yan-hui; Xiong, Wei; Yu, Peng-tao

2010-10-01

Based on field observation and modeling analysis, this paper studied the canopy interception, interception capacity, and some parameters for interception modeling of main forest types in Liupan Mountains of China. For the test main forest types, the ratio of their canopy interception to precipitation ranged from 8.59% to 17.94%, throughfall was more than 80%, and stemflow ranged from 0.23% to 3.10%. The canopy interception capacity was 0.78-1.88 mm, among which, leaf interception capacity was 0.62-1.63 mm, and stem interception capacity was 0.13-0.29 mm. Conifer forest had a higher canopy interception capacity than broad-leaved forest. The modified model considering the change of leaf area index, which was used in this paper, had a higher simulating precision than the interception model used before. The simulation results for Betula albo-sinensis forest, Pinus armandii forest, Prunus shrub, and Quercus liaotungensis-Tilia paucicostata forest were good, but those for Quercus liaotungensis forest, Pinus tabulaeformis forest, and Acer tetramerum and Euonymus sanguineus shrub were bad, which might be related to the differences in canopy structure, leaf area index, and precipitation characteristics.

[Canopy interception of sub-alpine dark coniferous communities in western Sichuan, China].

PubMed

Lü, Yu-liang; Liu, Shi-rong; Sun, Peng-sen; Liu, Xing-liang; Zhang, Rui-pu

2007-11-01

Based on field measurements of throughfall and stemflow in combination with climatic data collected from the meteorological station adjacent to the studied sub-alpine dark coniferous forest in Wolong, Sichuan Province, canopy interception of sub-alpine dark coniferous forests was analyzed and modeled at both stand scale and catchment scale. The results showed that monthly interception rate of Fargesia nitida, Bashania fangiana--Abies faxoniana old-growth ranged from 33% Grass to 72%, with the average of 48%. In growing season, there was a linear or powerful or exponential relationship between rainfall and interception an. a negative exponential relationship between rainfall and interception rate. The mean maximum canopy interception by the vegetation in the catchment of in.44 km was 1.74 ment and the significant differences among the five communities occurred in the following sequence: Moss-Fargesia nitida, Bashan afanglana-A. faxoniana stand > Grass-F. nitida, B. fangiana-A. faxoniana stand > Moss-Rhododendron spp.-A. faxoniana stand > Grass-Rh. spp.-A. faxoniana stand > Rh. spp. shrub. In addition, a close linear relationship existed between leaf area index (LAI) and maximum canopy interception. The simulated value of canopy interception rate, maximum canopy interception rate and addition interception rate of the vegetation in the catchment were 39%, 25% and 14%, respectively. Simulation of the canopy interception model was better at the overall growing season scale, that the mean relative error was 9%-14%.

Canopy interception variability in changing climate

NASA Astrophysics Data System (ADS)

Kalicz, Péter; Herceg, András; Kisfaludi, Balázs; Csáki, Péter; Gribovszki, Zoltán

2017-04-01

Tree canopies play a rather important role in forest hydrology. They intercept significant amounts of precipitation and evaporate back into the atmosphere during and after precipitation event. This process determines the net intake of forest soils and so important factor of hydrological processes in forested catchments. Average amount of interception loss is determined by the storage capacity of tree canopies and the rainfall distribution. Canopy storage capacity depends on several factors. It shows strong correlation with the leaf area index (LAI). Some equations are available to quantify this dependence. LAI shows significant variability both spatial and temporal scale. There are several methods to derive LAI from remote sensed data which helps to follow changes of it. In this study MODIS sensor based LAI time series are used to estimate changes of the storage capacity. Rainfall distribution derived from the FORESEE database which is developed for climate change related impact studies in the Carpathian Basin. It contains observation based precipitation data for the past and uses bias correction method for the climate projections. In this study a site based estimation is outworked for the Sopron Hills area. Sopron Hills is located at the eastern foothills of the Alps in Hungary. The study site, namely Hidegvíz Valley experimental catchment, is located in the central valley of the Sopron Hills. Long-term interception measurements are available in several forest sites in Hidegvíz Valley. With the combination of the ground based observations, MODIS LAI datasets a simple function is developed to describe the average yearly variations in canopy storage. Interception measurements and the CREMAP evapotranspiration data help to calibrate a simple interception loss equation based on Merriam's work. Based on these equation and the FORESEE bias corrected precipitation data an estimation is outworked for better understanding of the feedback of forest crown on hydrological

Contrasting roles of interception and transpiration in the hydrological cycle - Part 2: Moisture recycling

NASA Astrophysics Data System (ADS)

van der Ent, R. J.; Wang-Erlandsson, L.; Keys, P. W.; Savenije, H. H. G.

2014-12-01

The contribution of land evaporation to local and remote precipitation (i.e. moisture recycling) is of significant importance to sustain water resources and ecosystems. But how important are different evaporation components in sustaining precipitation? This is the first paper to present moisture recycling metrics for partitioned evaporation. In the companion paper Wang-Erlandsson et al. (2014) (hereafter Part 1), evaporation was partitioned into vegetation interception, floor interception, soil moisture evaporation and open-water evaporation (constituting the direct, purely physical fluxes, largely dominated by interception), and transpiration (delayed, biophysical flux). Here, we track these components forward as well as backward in time. We also include age tracers to study the atmospheric residence times of these evaporation components. We present a new image of the global hydrological cycle that includes quantification of partitioned evaporation and moisture recycling as well as the atmospheric residence times of all fluxes. We demonstrate that evaporated interception is more likely to return as precipitation on land than transpired water. On average, direct evaporation (essentially interception) is found to have an atmospheric residence time of 8 days, while transpiration typically resides for 9 days in the atmosphere. The process scale over which evaporation recycles is more local for interception compared to transpiration; thus interception generally precipitates closer to its evaporative source than transpiration, which is particularly pronounced outside the tropics. We conclude that interception mainly works as an intensifier of the local hydrological cycle during wet spells and wet seasons. On the other hand, transpiration remains active during dry spells and dry seasons and is transported over much larger distances downwind, where it can act as a significant source of moisture. Thus, as various land-use types can differ considerably in their partitioning

Intrastorm scale rainfall interception dynamics in a mature coniferous forest stand

NASA Astrophysics Data System (ADS)

Iida, Shin'ichi; Levia, Delphis F.; Shimizu, Akira; Shimizu, Takanori; Tamai, Koji; Nobuhiro, Tatsuhiko; Kabeya, Naoki; Noguchi, Shoji; Sawano, Shinji; Araki, Makoto

2017-05-01

Canopy interception of rainfall is an important process in the water balance of forests. The intrastorm dynamics of canopy interception is less well understood than event scale interception. Accordingly, armed with measurements of hourly interception intensity (i) from the field, this study is among the first to examine the differences in canopy interception dynamics between the first and second halves of rainfall events to quantify dynamic storage values for a coniferous forest in Japan. At this site, experimental results demonstrated that: (1) the relationship between interception loss (I) and gross rainfall (GR) at the event scale is better explained by a parabolic curve than a linear relationship, and there is a low correlation between rainfall intensity (gr) and i; (2) the ratio of accumulated i during the first half (IF) to that of gr (GRF) was larger than the second half (IS/GRS), with no significant correlations between potential evaporation during first half (PEF) vs IF or the second half (PES) vs IS; and (3) water storage capacity was similar to the magnitude of maximum I. By emphasizing the comparison between IF and IS, this study concludes that the water storage on tree surface is more important than losses by wet canopy evaporation and splash during rain. This study also adds insights into intrastorm interception dynamics of coniferous forests which are necessary to better model and forecast interception losses.

SHIIVER (Structural Heat Intercept Insulation Vibration Evaluation Rig)

NASA Image and Video Library

2017-06-11

SHIIVER (Structural Heat Intercept Insulation Vibration Evaluation Rig) is a cryogenic test tank developed to evaluate heat intercept concepts. It arrived at Marshall Space Flight Center on August 10, 2017. The tank will receive heat sensors and spray-on foam insulation before making its way to Plum Brook station for further insulation and testing.

Visuo-motor coordination and internal models for object interception.

PubMed

Zago, Myrka; McIntyre, Joseph; Senot, Patrice; Lacquaniti, Francesco

2009-02-01

Intercepting and avoiding collisions with moving objects are fundamental skills in daily life. Anticipatory behavior is required because of significant delays in transforming sensory information about target and body motion into a timed motor response. The ability to predict the kinematics and kinetics of interception or avoidance hundreds of milliseconds before the event may depend on several different sources of information and on different strategies of sensory-motor coordination. What are exactly the sources of spatio-temporal information and what are the control strategies remain controversial issues. Indeed, these topics have been the battlefield of contrasting views on how the brain interprets visual information to guide movement. Here we attempt a synthetic overview of the vast literature on interception. We discuss in detail the behavioral and neurophysiological aspects of interception of targets falling under gravity, as this topic has received special attention in recent years. We show that visual cues alone are insufficient to predict the time and place of interception or avoidance, and they need to be supplemented by prior knowledge (or internal models) about several features of the dynamic interaction with the moving object.

The influence of visual motion on interceptive actions and perception.

PubMed

Marinovic, Welber; Plooy, Annaliese M; Arnold, Derek H

2012-05-01

Visual information is an essential guide when interacting with moving objects, yet it can also be deceiving. For instance, motion can induce illusory position shifts, such that a moving ball can seem to have bounced past its true point of contact with the ground. Some evidence suggests illusory motion-induced position shifts bias pointing tasks to a greater extent than they do perceptual judgments. This, however, appears at odds with other findings and with our success when intercepting moving objects. Here we examined the accuracy of interceptive movements and of perceptual judgments in relation to simulated bounces. Participants were asked to intercept a moving disc at its bounce location by positioning a virtual paddle, and then to report where the disc had landed. Results showed that interceptive actions were accurate whereas perceptual judgments were inaccurate, biased in the direction of motion. Successful interceptions necessitated accurate information concerning both the location and timing of the bounce, so motor planning evidently had privileged access to an accurate forward model of bounce timing and location. This would explain why people can be accurate when intercepting a moving object, but lack insight into the accurate information that had guided their actions when asked to make a perceptual judgment. Copyright © 2012 Elsevier Ltd. All rights reserved.

How might Australian rainforest cloud interception respond to climate change?

NASA Astrophysics Data System (ADS)

Wallace, Jim; McJannet, Dave

2013-02-01

SummaryThe lower and upper montane rainforests in northern Queensland receive significant amounts of cloud interception that affect both in situ canopy wetness and downstream runoff. Cloud interception contributes 5-30% of the annual water input to the canopy and this increases to 40-70% of the monthly water input during the dry season. This occult water is therefore an important input to the canopy, sustaining the epiphytes, mosses and other species that depend on wet canopy conditions. The potential effect of climate change on cloud interception was examined using the relationship between cloud interception and cloud frequency derived from measurements made at four different rainforest locations. Any given change in cloud frequency produces a greater change in cloud interception and this 'amplification' increases from 1.1 to 1.7 as cloud frequency increases from 5% to 70%. This means that any changes in cloud frequency will have the greatest relative effects at the higher altitude sites where cloud interception is greatest. As cloud frequency is also a major factor affecting canopy wetness, any given change in cloud frequency will therefore have a greater impact on canopy wetness at the higher altitude sites. These changes in wetness duration will augment those due to changes in rainfall and may have important implications for the fauna and flora that depend on wet canopy conditions. We also found that the Australian rainforests may be more efficient (by ˜50% on average) in intercepting cloud water than American coniferous forests, which may be due to differences in canopy structure and exposure at the different sites.

Rainfall interception from a lowland tropical rainforest in Brunei

NASA Astrophysics Data System (ADS)

Dykes, A. P.

1997-12-01

Results from a programme of throughfall measurements in a lowland tropical rainforest in Brunei, northwest Borneo, indicate that interception losses amount to 18% of the gross incident rainfall. The high annual rainfall experienced by the study area results in annual interception losses of around 800 mm, which may result in total annual evapotranspiration losses significantly higher than in other rainforest locations. An improved version of Gash's analytical interception model is tested on the available data using assumed values for the "forest" parameters, and is found to predict interception losses extremely well. The model predictions are based on an estimated evaporation rate during rainfall of 0.71 mm h -1. This is significantly higher than has been reported in other tropical studies. It is concluded that these results are distinctive when compared with previous results from rainforests, and that further, detailed work is required to establish whether the enhanced evaporation rate is due to advective effects associated with the maritime setting of the study area.

SHIIVER (Structural Heat Intercept Insulation Vibration Evaluation Rig)

NASA Image and Video Library

2017-06-11

SHIIVER Tank Arrives at NASA’s Marshall Center for Spray-On Foam InsulationSHIIVER (Structural Heat Intercept Insulation Vibration Evaluation Rig) is a cryogenic test tank developed to evaluate heat intercept concepts. It arrived at Marshall Space Flight Center on August 10, 2017. The tank will receive heat sensors and spray-on foam insulation before making its way to Plum Brook station for further insulation and testing.

SHIIVER (Structural Heat Intercept Insulation Vibration Evaluation Rig)

NASA Image and Video Library

2017-06-11

SHIIVER (Structural Heat Intercept Insulation Vibration Evaluation Rig) is a cryogenic test tank developed to evaluate heat intercept concepts. It arrived at Marshall Space Flight Center on August 10, 2017. The tank will receive heat sensors and spray-on foam insulation before making its way to Plum Brook station for further insulation and testing.SHIIVER Tank Arrives at NASA’s Marshall Center for Spray-On Foam Insulation

Intercepting virtual balls approaching under different gravity conditions: evidence for spatial prediction.

PubMed

Russo, Marta; Cesqui, Benedetta; La Scaleia, Barbara; Ceccarelli, Francesca; Maselli, Antonella; Moscatelli, Alessandro; Zago, Myrka; Lacquaniti, Francesco; d'Avella, Andrea

2017-10-01

To accurately time motor responses when intercepting falling balls we rely on an internal model of gravity. However, whether and how such a model is also used to estimate the spatial location of interception is still an open question. Here we addressed this issue by asking 25 participants to intercept balls projected from a fixed location 6 m in front of them and approaching along trajectories with different arrival locations, flight durations, and gravity accelerations (0 g and 1 g ). The trajectories were displayed in an immersive virtual reality system with a wide field of view. Participants intercepted approaching balls with a racket, and they were free to choose the time and place of interception. We found that participants often achieved a better performance with 1 g than 0 g balls. Moreover, the interception points were distributed along the direction of a 1 g path for both 1 g and 0 g balls. In the latter case, interceptions tended to cluster on the upper half of the racket, indicating that participants aimed at a lower position than the actual 0 g path. These results suggest that an internal model of gravity was probably used in predicting the interception locations. However, we found that the difference in performance between 1 g and 0 g balls was modulated by flight duration, the difference being larger for faster balls. In addition, the number of peaks in the hand speed profiles increased with flight duration, suggesting that visual information was used to adjust the motor response, correcting the prediction to some extent. NEW & NOTEWORTHY Here we show that an internal model of gravity plays a key role in predicting where to intercept a fast-moving target. Participants also assumed an accelerated motion when intercepting balls approaching in a virtual environment at constant velocity. We also show that the role of visual information in guiding interceptive movement increases when more time is available. Copyright © 2017 the American Physiological

Context effects on smooth pursuit and manual interception of a disappearing target.

PubMed

Kreyenmeier, Philipp; Fooken, Jolande; Spering, Miriam

2017-07-01

In our natural environment, we interact with moving objects that are surrounded by richly textured, dynamic visual contexts. Yet most laboratory studies on vision and movement show visual objects in front of uniform gray backgrounds. Context effects on eye movements have been widely studied, but it is less well known how visual contexts affect hand movements. Here we ask whether eye and hand movements integrate motion signals from target and context similarly or differently, and whether context effects on eye and hand change over time. We developed a track-intercept task requiring participants to track the initial launch of a moving object ("ball") with smooth pursuit eye movements. The ball disappeared after a brief presentation, and participants had to intercept it in a designated "hit zone." In two experiments ( n = 18 human observers each), the ball was shown in front of a uniform or a textured background that either was stationary or moved along with the target. Eye and hand movement latencies and speeds were similarly affected by the visual context, but eye and hand interception (eye position at time of interception, and hand interception timing error) did not differ significantly between context conditions. Eye and hand interception timing errors were strongly correlated on a trial-by-trial basis across all context conditions, highlighting the close relation between these responses in manual interception tasks. Our results indicate that visual contexts similarly affect eye and hand movements but that these effects may be short-lasting, affecting movement trajectories more than movement end points. NEW & NOTEWORTHY In a novel track-intercept paradigm, human observers tracked a briefly shown object moving across a textured, dynamic context and intercepted it with their finger after it had disappeared. Context motion significantly affected eye and hand movement latency and speed, but not interception accuracy; eye and hand position at interception were

Airborne Intercept Monitoring

DTIC Science & Technology

2006-04-01

Primary mirror of Zerodur with Pilkington 747 coating • FOV = 0.104 degrees Airborne Intercept Monitoring RTO-MP-SET-105 16 - 3 UNCLASSIFIED...Pointing System (SPS). The STS is a 0.75 meter aperture Mersenne Cassegrain telescope and the SAT is a 0.34 meter aperture 3- mirror anastigmat telescope...UNLIMITED UNCLASSIFIED/UNLIMITED • Air Flow to Mitigate Thermal “Seeing” Effects • Light weighted primary mirror to reduce mass The SAT

Calibrated intercepts for solar radiometers used in remote sensor calibration

NASA Technical Reports Server (NTRS)

Gellman, David I.; Biggar, Stuart F.; Slater, Philip N.; Bruegge, Carol J.

1991-01-01

Calibrated solar radiometer intercepts allow spectral optical depths to be determined for days with intermittently clear skies. This is of particular importance on satellite sensor calibration days that are cloudy except at the time of image acquisition. This paper describes the calibration of four solar radiometers using the Langley-Bouguer technique for data collected on days with a clear, stable atmosphere. Intercepts are determined with an uncertainty of less than six percent, corresponding to a maximum uncertainty of 0.06 in optical depth. The spread of voltage intercepts calculated in this process is carried through three methods of radiometric calibration of satellite sensors to yield an uncertainty in radiance at the top of the atmosphere of less than one percent associated with the uncertainty in solar radiometer intercepts for a range of ground reflectances.

Interception processes during snowstorms

Treesearch

David H. Miller

1964-01-01

Four processes are identified as determining the initial interception of falling snow by forest during storms: delivery of snow particles from the airstream to the forest; true throughfall of particles to the forest floor; impaction and adhesion of particles to foliage and branches; and cohesion of particles into masses of snow. Delivery and impaction processes seem...

Barriers and dispersal surfaces in minimum-time interception

NASA Technical Reports Server (NTRS)

Rajan, N.; Ardema, M. D.

1982-01-01

Minimum time interception of a target moving in a horizontal plane is analyzed as a one-player differential game. Dispersal points and points on the barrier are located for a class of pursuit evasion and interception problems. These points are determined by constructing cross sections of the isochrones and hence obtaining the barrier, dispersal, and control level surfaces. The game solution maps the controls as a function of the state within the capture region.

Rainfall interception by annual grass and chaparral . . . losses compared

Treesearch

Edward S. Corbett; Robert P. Crouse

1968-01-01

Loss of precipitation due to interception by annual grass and grass litter was measured during three rainy seasons on the San Dimas Experimental Forest, in southern California. Interception loss from annual grass averaged 7.9 percent; that from mature chaparral cover, 12.8 percent. If chaparral stands were converted to grass, an estimated 1.3 inches of gross...

Interception of spray drift by border structures. Part 1: wind tunnel experiments.

PubMed

De Schampheleire, M; Nuyttens, D; Dekeyser, D; Verboven, P; Cornelis, W; Gabriels, D; Spanoghe, P

2008-01-01

This research investigated the drift-intercepting potential of structures surrounding the field borders, like artificial screens and crops, which are not yet a part of the drift mitigation measures for field crop sprayers in Belgium. Drift-interception experiments were performed in the wind tunnel of the International Centre for Eremology (Ghent University, Belgium) with various interception structures: Artificial screens with heights of 0.5, 0.75 and 1 m and screen open areas of 16, 36 and 63%; a row of plastic Christmas trees with heights of 0.5 and 0.75 m; and a potato canopy. The interception structure was positioned at 1 m from the field border. From the results it was found that type of border structure has a pronounced effect on the drift interception, while the height of the border structure had no significant effect.

On interception modelling of a lowland coastal rainforest in northern Queensland, Australia

NASA Astrophysics Data System (ADS)

Wallace, Jim; McJannet, Dave

2006-10-01

SummaryRecent studies of the water balance of tropical rainforests in northern Queensland have revealed that large fractions of rainfall, up to 30%, are intercepted by the canopy and lost as evaporation. These loss rates are much higher than those reported for continental rainforests, for example, in the Amazon basin, where interception is around 9% of rainfall. Higher interception losses have been found in coastal and mountain rainforests and substantial advection of energy during rainfall is proposed to account for these results. This paper uses a process based model of interception to analyse the interception losses at Oliver Creek, a lowland coastal rainforest site in northern Queensland with a mean annual rainfall of 3952 mm. The observed interception loss of 25% of rainfall for the period August 2001 to January 2004 can be reproduced by the model with a suitable choice of the three key controlling variables, the canopy storage capacity, mean rainfall rate and mean wet canopy evaporation rate. Our analyses suggest that the canopy storage capacity of the Oliver Creek rainforest is between 3.0 and 3.5 mm, higher than reported for most other rainforests. Despite the high canopy capacity at our site, the interception losses can only be accounted for with energy advection during rainfall in the range 40-70% of the incident energy.

Estimating Vegetation Rainfall Interception Using Remote Sensing Observations at Very High Resolution

NASA Astrophysics Data System (ADS)

Cui, Y.; Zhao, P.; Hong, Y.; Fan, W.; Yan, B.; Xie, H.

2017-12-01

Abstract: As an important compont of evapotranspiration, vegetation rainfall interception is the proportion of gross rainfall that is intercepted, stored and subsequently evaporated from all parts of vegetation during or following rainfall. Accurately quantifying the vegetation rainfall interception at a high resolution is critical for rainfall-runoff modeling and flood forecasting, and is also essential for understanding its further impact on local, regional, and even global water cycle dynamics. In this study, the Remote Sensing-based Gash model (RS-Gash model) is developed based on a modified Gash model for interception loss estimation using remote sensing observations at the regional scale, and has been applied and validated in the upper reach of the Heihe River Basin of China for different types of vegetation. To eliminate the scale error and the effect of mixed pixels, the RS-Gash model is applied at a fine scale of 30 m with the high resolution vegetation area index retrieved by using the unified model of bidirectional reflectance distribution function (BRDF-U) for the vegetation canopy. Field validation shows that the RMSE and R2 of the interception ratio are 3.7% and 0.9, respectively, indicating the model's strong stability and reliability at fine scale. The temporal variation of vegetation rainfall interception loss and its relationship with precipitation are further investigated. In summary, the RS-Gash model has demonstrated its effectiveness and reliability in estimating vegetation rainfall interception. When compared to the coarse resolution results, the application of this model at 30-m fine resolution is necessary to resolve the scaling issues as shown in this study. Keywords: rainfall interception; remote sensing; RS-Gash analytical model; high resolution

Schema generation in recurrent neural nets for intercepting a moving target.

PubMed

Fleischer, Andreas G

2010-06-01

The grasping of a moving object requires the development of a motor strategy to anticipate the trajectory of the target and to compute an optimal course of interception. During the performance of perception-action cycles, a preprogrammed prototypical movement trajectory, a motor schema, may highly reduce the control load. Subjects were asked to hit a target that was moving along a circular path by means of a cursor. Randomized initial target positions and velocities were detected in the periphery of the eyes, resulting in a saccade toward the target. Even when the target disappeared, the eyes followed the target's anticipated course. The Gestalt of the trajectories was dependent on target velocity. The prediction capability of the motor schema was investigated by varying the visibility range of cursor and target. Motor schemata were determined to be of limited precision, and therefore visual feedback was continuously required to intercept the moving target. To intercept a target, the motor schema caused the hand to aim ahead and to adapt to the target trajectory. The control of cursor velocity determined the point of interception. From a modeling point of view, a neural network was developed that allowed the implementation of a motor schema interacting with feedback control in an iterative manner. The neural net of the Wilson type consists of an excitation-diffusion layer allowing the generation of a moving bubble. This activation bubble runs down an eye-centered motor schema and causes a planar arm model to move toward the target. A bubble provides local integration and straightening of the trajectory during repetitive moves. The schema adapts to task demands by learning and serves as forward controller. On the basis of these model considerations the principal problem of embedding motor schemata in generalized control strategies is discussed.

Two zero-flow pressure intercepts exist in autoregulating isolated skeletal muscle.

PubMed

Braakman, R; Sipkema, P; Westerhof, N

1990-06-01

The autoregulating vascular bed of the isolated canine extensor digitorum longus muscle was investigated for the possible existence of two positive zero-flow pressure axis intercepts, a tone-dependent one and a tone-independent one. An isolated preparation, perfused with autologous blood, was used to exclude effects of collateral flow and nervous and humoral regulation while autoregulation was left intact [mean autoregulatory gain 0.50 +/- 0.24 (SD)]. In a first series of experiments, the steady-state (zero flow) pressure axis intercept [mean 8.9 +/- 2.6 (SD) mmHg, tone independent] and the instantaneous (zero flow) pressure axis intercept [mean 28.5 +/- 9.9 (SD) mmHg, tone dependent] were determined as a function of venous pressure (range: 0-45 mmHg) and were independent of venous pressure until the venous pressure exceeded their respective values. Beyond this point the relations between the venous pressure and the steady-state and instantaneous pressure axis intercept followed the line of identity. The findings agree with the predictions of the vascular waterfall model. In a second series it was shown by means of administration of vasoactive drugs that the instantaneous pressure axis intercept is tone dependent, whereas the steady-state pressure axis intercept is not. It is concluded that there is a (proximal) tone-dependent zero-flow pressure at the arteriolar level and a (distal) tone-independent zero-flow pressure at the venous level.

Proceedings of the Near-Earth-Object Interception Workshop

NASA Technical Reports Server (NTRS)

Canavan, G. J. (Editor); Solem, J. C. (Editor); Rather, John D. G. (Editor)

1993-01-01

The National Aeronautics and Space Administration Headquarters sponsored the Near-Earth-Object Interception Workshop hosted by the Los Alamos National Laboratory on 14-16 Jan. 1992 at the J. Robert Oppenheimer Study Center in Los Alamos, New Mexico. The Workshop evaluated the issues involved in intercepting celestial objects that could hit the Earth. It covered the technologies for acquiring, tracking, and homing, as well as those for sending interceptors to inspect, rendezvous with, land on, irradiate, deflect, or destroy them. This report records the presentations and technical options reviewed.

Cloud water interception and canopy water balance in the Hawaiian Islands: preliminary results and emerging patterns

NASA Astrophysics Data System (ADS)

Tseng, H.; Giambelluca, T. W.; DeLay, J. K.; Nullet, M.

2017-12-01

Steep climate gradients and diverse ecosystems make the Hawaiian Islands an ideal laboratory for ecohydrological experiments. Researchers are able to control physical and ecological variables, which is difficult for most environmental studies, by selecting sites along these gradients. Tropical montane forests, especially those situated in the cloud zone, are known to improve recharge and sustain baseflow. This is probably the result of frequent and persistent fog characteristic to these systems. During fog events, evapotranspiration is suppressed due to high humidity and reduced solar radiation. Moreover, cloud water interception by the forest canopy can produce fog drip and contribute significantly to the local water budget. Because the interception process is a complex interaction between the atmosphere and the vegetation, the effects of the meteorological conditions and canopy characteristics are equally important and sometimes hard to separate. This study aims to examine patterns in cloud water interception and canopy water balance across five tropical montane forest sites on three of the main islands of Hawaii. The sites cover a range of elevations between 1100- 2114 m, annual rainfall between 1155-3375 mm, and different dominant plant species with canopy heights ranging from 1.5 m to 30 m. We investigate the effect of climatic factors by comparing passive fog gauge measurements and other meteorological variables, then examine the differences in canopy water balance by comparing throughfall and stemflow measurements at these sites. While this study is ongoing, we present the first few months of field observations and the results of preliminary analyses. This study will improve understanding of how large-scale climate and vegetation factors interact to control cloud water interception and will inform ongoing watershed management. This is particularly important for oceanic islands such as Hawaii because they rely on precipitation entirely for water supply and

Suborbital Asteroid Intercept and Fragmentation for Very Short Warning Time Scenarios

NASA Technical Reports Server (NTRS)

Hupp, Ryan; Dewald, Spencer; Wie, Bong; Barbee, Brent W.

2015-01-01

Small near-Earth objects (NEOs) 50150 m in size are far more numerous (hundreds of thousands to millions yet to be discovered) than larger NEOs. Small NEOs, which are mostly asteroids rather than comets, are very faint in the night sky due to their small sizes, and are, therefore, difficult to discover far in advance of Earth impact. However, even small NEOs are capable of creating explosions with energies on the order of tens or hundreds of megatons (Mt).We are, therefore, motivated to prepare to respond effectively to short warning time, small NEO impact scenarios. In this paper we explore the lower bound on actionable warning time by investigating the performance of notional upgraded Intercontinental Ballistic Missiles (ICBMs) to carry Nuclear Explosive Device (NED) payloads to intercept and disrupt a fictitious incoming NEO at high altitudes (generally, at least 2500 km above Earth). We conduct this investigation by developing optimal NEO intercept trajectories for a range of cases and comparing their performances.Our results show that suborbital NEO intercepts using Minuteman III or SM-3 IIA launch vehicles could achieve NEO intercept a few minutes prior to when the NEOwould strike Earth. We also find that more powerful versions of the launch vehicles (e.g., total V 9.511 kms) could intercept incoming NEOs over a day prior to when the NEO would strike Earth, if launched at least several days prior to the time of NEO intercept. Finally, we discuss a number of limiting factors and practicalities that affect whether the notional systems we describe could become feasible.

Artificial night light alters nocturnal prey interception outcomes for morphologically variable spiders.

PubMed

Yuen, Suet Wai; Bonebrake, Timothy C

2017-01-01

Artificial night light has the potential to significantly alter visually-dependent species interactions. However, examples of disruptions of species interactions through changes in light remain rare and how artificial night light may alter predator-prey relationships are particularly understudied. In this study, we examined whether artificial night light could impact prey attraction and interception in Nephila pilipes orb weaver spiders, conspicuous predators who make use of yellow color patterns to mimic floral resources and attract prey to their webs. We measured moth prey attraction and interception responses to treatments where we experimentally manipulated the color/contrast of spider individuals in the field (removed yellow markings) and also set up light manipulations. We found that lit webs had lower rates of moth interception than unlit webs. Spider color, however, had no clear impact on moth interception or attraction rates in lit nor unlit webs. The results show that night light can reduce prey interception for spiders. Additionally, this study highlights how environmental and morphological variation can complicate simple predictions of ecological light pollution's disruption of species interactions.

Quantifying interception associated with new urban vegetation canopies

NASA Astrophysics Data System (ADS)

Yerk, W.; Montalto, F. A.

2013-12-01

Interception of precipitation by vegetation canopies has long been recognized as an important component of the hydrologic cycle, though most research has been in closed or sparse canopy forests. Much less work has been published on interception by urban vegetation, and especially associated with the low growing shrubs commonly installed in green infrastructure program. To inform urban watershed model with vegetation-specific interception data, a field experiment was designed to directly measure canopy throughfall associated with two shrub species commonly included in urban greening programs. Data was collected at a high (e.g. five second) sampling frequency. A non-parametric Kruskal-Wallis test performed on data collected between August and October of 2012 demonstrated statistically significant (p= 0.0011) differences in recorded throughfall between two species (94% for Itea virginica, 86% for Cornus sericea). Additionally, the results suggested that the relationship of throughfall to rainfall intensity varied by species. For Itea, the ratio of throughfall to precipitation intensity was close to 1:1. However, for Cornus, the throughfall rate was on average slower (or 0.85 of the precipitation intensity). An improved and expanded set-up installed in 2013 added two additional species (Prunus laurocerasus and Hydrangea quercifolia). The 2013 results confirm interspecies differences in both throughfall amount, and in the relationship of throughfall rate to precipitation intensity. The results are discussed with respect to droplet splashing and enhanced evaporation within the canopy. Both years' findings suggest that the quantity of water intercepted by vegetation canopies exceeds the canopy storage capacity, as assumed in many conventional hydrologic models.

Eye movements and manual interception of ballistic trajectories: effects of law of motion perturbations and occlusions.

PubMed

Delle Monache, Sergio; Lacquaniti, Francesco; Bosco, Gianfranco

2015-02-01

Manual interceptions are known to depend critically on integration of visual feedback information and experience-based predictions of the interceptive event. Within this framework, coupling between gaze and limb movements might also contribute to the interceptive outcome, since eye movements afford acquisition of high-resolution visual information. We investigated this issue by analyzing subjects' head-fixed oculomotor behavior during manual interceptions. Subjects moved a mouse cursor to intercept computer-generated ballistic trajectories either congruent with Earth's gravity or perturbed with weightlessness (0 g) or hypergravity (2 g) effects. In separate sessions, trajectories were either fully visible or occluded before interception to enforce visual prediction. Subjects' oculomotor behavior was classified in terms of amounts of time they gazed at different visual targets and of overall number of saccades. Then, by way of multivariate analyses, we assessed the following: (1) whether eye movement patterns depended on targets' laws of motion and occlusions; and (2) whether interceptive performance was related to the oculomotor behavior. First, we found that eye movement patterns depended significantly on targets' laws of motion and occlusion, suggesting predictive mechanisms. Second, subjects coupled differently oculomotor and interceptive behavior depending on whether targets were visible or occluded. With visible targets, subjects made smaller interceptive errors if they gazed longer at the mouse cursor. Instead, with occluded targets, they achieved better performance by increasing the target's tracking accuracy and by avoiding gaze shifts near interception, suggesting that precise ocular tracking provided better trajectory predictions for the interceptive response.

Examining the canopy interception at a forest field site using cosmic-ray neutron detection

NASA Astrophysics Data System (ADS)

Andreasen, M.; Looms, M.; Christiansen, J. R.; Sonnenborg, T. O.; Stisen, S.; Jensen, K. H.

2017-12-01

Canopy interception, the amount of precipitation captured by the surface of plants and trees, is a key component of the water cycle as it constrains the water flux to the ground below vegetation. Forests have especially high interception capacities and therefore the interception loss often forms a considerable part of the total evapotranspiration. The canopy interception capacity is dependent on the size and structure of the vegetation, and the interception loss can vary substantial in time and space. Measuring the canopy interception loss directly is challenging and current methodologies only represent small areas and rely on indirect approaches. Improving methods to estimate canopy interception loss directly will forward the basic understanding of how vegetation structure interacts with the water cycle and hence prediction of evapotranspiration. The intensity of low-energy neutrons produced by cosmic-rays, measured above the ground surface, is sensitive to the hydrogen content in the upper decimeters of the ground and hence the soil moisture content from a radius of hundreds of meters in the horizontal direction. In order to advance the cosmic-ray neutron (CRN) soil moisture method and extend the application of the CRN method more research has recently focused on the signal of other hydrogen pools on the neutron intensity (e.g., vegetation and canopy interception). A recent study, based on neutron transport modeling, found that the ground level thermal neutron intensity (energy < 1 eV), and as a consequence also the thermal-to-epithermal neutron (T/E) ratio (epithermal energy > 1 eV), increased with increasing canopy interception. In this study, we test whether CRN measurements can be used to provide a direct measure of the canopy interception. Four sets of CR2000/B systems were installed below the canopy in an oak forest stand in Denmark. Each system holds a bare (primarily measuring thermal neutrons) and a moderated detector (primarily measuring epithermal

Catching what we can't see: manual interception of occluded fly-ball trajectories.

PubMed

Bosco, Gianfranco; Delle Monache, Sergio; Lacquaniti, Francesco

2012-01-01

Control of interceptive actions may involve fine interplay between feedback-based and predictive mechanisms. These processes rely heavily on target motion information available when the target is visible. However, short-term visual memory signals as well as implicit knowledge about the environment may also contribute to elaborate a predictive representation of the target trajectory, especially when visual feedback is partially unavailable because other objects occlude the visual target. To determine how different processes and information sources are integrated in the control of the interceptive action, we manipulated a computer-generated visual environment representing a baseball game. Twenty-four subjects intercepted fly-ball trajectories by moving a mouse cursor and by indicating the interception with a button press. In two separate sessions, fly-ball trajectories were either fully visible or occluded for 750, 1000 or 1250 ms before ball landing. Natural ball motion was perturbed during the descending trajectory with effects of either weightlessness (0 g) or increased gravity (2 g) at times such that, for occluded trajectories, 500 ms of perturbed motion were visible before ball disappearance. To examine the contribution of previous visual experience with the perturbed trajectories to the interception of invisible targets, the order of visible and occluded sessions was permuted among subjects. Under these experimental conditions, we showed that, with fully visible targets, subjects combined servo-control and predictive strategies. Instead, when intercepting occluded targets, subjects relied mostly on predictive mechanisms based, however, on different type of information depending on previous visual experience. In fact, subjects without prior experience of the perturbed trajectories showed interceptive errors consistent with predictive estimates of the ball trajectory based on a-priori knowledge of gravity. Conversely, the interceptive responses of subjects

Fractional-order information in the visual control of lateral locomotor interception.

PubMed

Bootsma, Reinoud J; Ledouit, Simon; Casanova, Remy; Zaal, Frank T J M

2016-04-01

Previous work on locomotor interception of a target moving in the transverse plane has suggested that interception is achieved by maintaining the target's bearing angle (often inadvertently confused and/or confounded with the target heading angle) at a constant value. However, dynamics-based model simulations testing the veracity of the underlying control strategy of nulling the rate of change in the bearing angle have been restricted to limited conditions of target motion, and only a few alternatives have been considered. Exploring a wide range of target motion characteristics with straight and curving ball trajectories in a virtual reality setting, we examined how soccer goalkeepers moved along the goal line to intercept long-range shots on goal, a situation in which interception is naturally constrained to movement along a single dimension. Analyses of the movement patterns suggested reliance on combinations of optical position and velocity for straight trajectories and optical velocity and acceleration for curving trajectories. As an alternative to combining such standard integer-order derivatives, we demonstrate with a simple dynamical model that nulling a single informational variable of a self-tuned fractional (rather than integer) order efficiently captures the timing and patterning of the observed interception behaviors. This new perspective could fundamentally change the conception of what perceptual systems may actually provide, both in humans and in other animals. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Metastability and emergent performance of dynamic interceptive actions.

PubMed

Pinder, Ross A; Davids, Keith; Renshaw, Ian

2012-09-01

Adaptive patterning of human movement is context specific and dependent on interacting constraints of the performer-environment relationship. Flexibility of skilled behaviour is predicated on the capacity of performers to move between different states of movement organisation to satisfy dynamic task constraints, previously demonstrated in studies of visual perception, bimanual coordination, and an interceptive combat task. Metastability is a movement system property that helps performers to remain in a state of relative coordination with their performance environments, poised between multiple co-existing states (stable and distinct movement patterns or responses). The aim of this study was to examine whether metastability could be exploited in externally paced interceptive actions in fast ball sports, such as cricket. Here we report data on metastability in performance of multi-articular hitting actions by skilled junior cricket batters (n=5). Participants' batting actions (key movement timings and performance outcomes) were analysed in four distinct performance regions varied by ball pitching (bounce) location. Results demonstrated that, at a pre-determined distance to the ball, participants were forced into a meta-stable region of performance where rich and varied patterns of functional movement behaviours emerged. Participants adapted the organisation of responses, resulting in higher levels of variability in movement timing in this performance region, without detrimental effects on the quality of interceptive performance outcomes. Findings provide evidence for the emergence of metastability in a dynamic interceptive action in cricket batting. Flexibility and diversity of movement responses were optimised using experiential knowledge and careful manipulation of key task constraints of the specific sport context. Copyright © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Gaze Behaviour during Interception in Children with Spastic Unilateral Cerebral Palsy

ERIC Educational Resources Information Center

van Kampen, P. M.; Ledebt, A.; Smorenburg, A. R. P.; Vermeulen, R. J.; Kelder, M. E.; van der Kamp, J.; Savelsbergh, G. J. P.

2012-01-01

Anticipatory gaze behaviour during interceptive movements was investigated in children with Spastic Unilateral Cerebral Palsy (SUCP), and related to the side of the intracerebral lesion. Five children with lesions of the right hemisphere (RHL) and five children with lesions of the left hemisphere (LHL) had to walk towards and intercept a ball that…

Intercepted Scolytidae (Coleoptera) at U.S. ports of entry: 1985-2000.

Treesearch

Robert A. Haack

2001-01-01

Since 1985, the U.S. Department of Agriculture, Animal and Plant Health Inspection Service has maintained the 'Port Information Network' (PIN) database for plant pests intercepted at the U.S. ports of entry. As of August 2001, PIN contained 6825 records of beetles (Coleoptera) in the family Scolytidae that had been intercepted during the years 1985-2000 from...

A Scottish cost analysis of interceptive orthodontics for thumb sucking habits.

PubMed

Borrie, Felicity R P; Elouafkaoui, Paula; Bearn, David R

2013-06-01

There is a potential cost saving to be made within the NHS by providing simple interceptive treatment rather than comprehensive treatment at a later date. The focus of this study is to determine the size of this potential cost by looking at the cost to NHS Tayside for the provision of interceptive treatment for cessation of thumb sucking and where this has been unsuccessful (or not provided) the costs of correction of the associated malocclusion. A cost analysis is described, investigating the costs of treatment solely to the NHS, both in the primary and secondary setting. Three potential treatment pathways are identified with the costs calculated for each pathway. The actual cost of providing this treatment in NHS Tayside, and the potential cost saving in Tayside if there was a change in clinical practice are calculated. Both discounting of costs and a sensitivity analysis are performed. The cost to NHS Tayside of current practice was calculated to be between £123,710 and £124,930 per annum. Change in practice to replace use of a removable with a fixed habit breaker for the interceptive treatment of thumb sucking reduced the calculated cost to between £99,581 and £105,017. A saving could be made to the NHS, both locally and nationally, if the provision of a removable habit breaker was changed to a fixed habit breaker. In addition, increasing the proportion receiving active treatment, in the form of a fixed habit breaker, rather than monitoring, would appear to further reduce the cost to the NHS considerably.

The importance of radiation for semiempirical water-use efficiency models

DOE PAGES

Boese, Sven; Jung, Martin; Carvalhais, Nuno; ...

2017-06-22

Water-use efficiency (WUE) is a fundamental property for the coupling of carbon and water cycles in plants and ecosystems. Existing model formulations predicting this variable differ in the type of response of WUE to the atmospheric vapor pressure deficit of water (VPD). We tested a representative WUE model on the ecosystem scale at 110 eddy covariance sites of the FLUXNET initiative by predicting evapotranspiration (ET) based on gross primary productivity (GPP) and VPD. We found that introducing an intercept term in the formulation increases model performance considerably, indicating that an additional factor needs to be considered. We demonstrate that thismore » intercept term varies seasonally and we subsequently associate it with radiation. Replacing the constant intercept term with a linear function of global radiation was found to further improve model predictions of ET. Our new semiempirical ecosystem WUE formulation indicates that, averaged over all sites, this radiation term accounts for up to half (39–47 %) of transpiration. These empirical findings challenge the current understanding of water-use efficiency on the ecosystem scale.« less

The importance of radiation for semiempirical water-use efficiency models

NASA Astrophysics Data System (ADS)

Boese, Sven; Jung, Martin; Carvalhais, Nuno; Reichstein, Markus

2017-06-01

Water-use efficiency (WUE) is a fundamental property for the coupling of carbon and water cycles in plants and ecosystems. Existing model formulations predicting this variable differ in the type of response of WUE to the atmospheric vapor pressure deficit of water (VPD). We tested a representative WUE model on the ecosystem scale at 110 eddy covariance sites of the FLUXNET initiative by predicting evapotranspiration (ET) based on gross primary productivity (GPP) and VPD. We found that introducing an intercept term in the formulation increases model performance considerably, indicating that an additional factor needs to be considered. We demonstrate that this intercept term varies seasonally and we subsequently associate it with radiation. Replacing the constant intercept term with a linear function of global radiation was found to further improve model predictions of ET. Our new semiempirical ecosystem WUE formulation indicates that, averaged over all sites, this radiation term accounts for up to half (39-47 %) of transpiration. These empirical findings challenge the current understanding of water-use efficiency on the ecosystem scale.

An Optimal t-{Delta}v Guidance Law for Intercepting a Boosting Target

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ng, L.C.; Breitfeller, E.; Ledebuhr, A.G.

2002-06-30

Lawrence Livermore National Laboratory (LLNL) have developed a new missile guidance law for intercepting a missile during boost phase. Unlike other known missile guidance laws being used today, the new t-{Delta}v guidance law optimally trades an interceptor's onboard fuel capacity against time-to-go before impact. In particular, this guidance law allows a missile designer to program the interceptor to maximally impact a boosting missile before burnout or burn termination and thus negating its ability to achieve the maximum kinetic velocity. For an intercontinental range ballistic missile (ICBM), it can be shown that for every second of earlier intercept prior to burnout,more » the ICBM ground range is reduced by 350 km. Therefore, intercepting a mere 15 seconds earlier would result in amiss of 5,250 km from the intended target or approximately a distance across the continental US. This paper also shows how the t-{Delta}v guidance law can incorporate uncertainties in target burnout time, predicted intercept point (PIP) error, time-to-go error, and other track estimation errors. The authors believe that the t-{Delta}v guidance law is a step toward the development of a new and smart missile guidance law that would enhance the probability of achieving a boost phase intercept.« less

Modelling rainfall interception by a lowland tropical rain forest in northeastern Puerto Rico

NASA Astrophysics Data System (ADS)

Schellekens, J.; Scatena, F. N.; Bruijnzeel, L. A.; Wickel, A. J.

1999-12-01

Recent surveys of tropical forest water use suggest that rainfall interception by the canopy is largest in wet maritime locations. To investigate the underlying processes at one such location—the Luquillo Experimental Forest in eastern Puerto Rico—66 days of detailed throughfall and above-canopy climatic data were collected in 1996 and analysed using the Rutter and Gash models of rainfall interception. Throughfall occurred on 80% of the days distributed over 80 rainfall events. Measured interception loss was 50% of gross precipitation. When Penman-Monteith based estimates for the wet canopy evaporation rate (0.11 mm h -1 on average) and a canopy storage of 1.15 mm were used, both models severely underestimated measured interception loss. A detailed analysis of four storms using the Rutter model showed that optimizing the model for the wet canopy evaporation component yielded much better results than increasing the canopy storage capacity. However, the Rutter model failed to properly estimate throughfall amounts during an exceptionally large event. The analytical model, on the other hand, was capable of representing interception during the extreme event, but once again optimizing wet canopy evaporation rates produced a much better fit than optimizing the canopy storage capacity. As such, the present results support the idea that it is primarily a high rate of evaporation from a wet canopy that is responsible for the observed high interception losses.

Comparison of ground and satellite based measurements of the fraction of photosynthetically active radiation intercepted by tall-grass prairie

NASA Technical Reports Server (NTRS)

Demetriades-Shah, T. H.; Kanemasu, E. T.; Flitcroft, I.; Su, H.

1990-01-01

The fraction, of photosynthetically active radiation absorbed by vegetation, F sub ipar, is an important requirement for estimating vegetation biomass productivity and related quantities. This was an integral part of a large international effort; the First ISLSCP Field Experiment (FIFE). The main objective of FIFE was to study the effects of vegetation on the land atmosphere interactions and to determine if these interactions can be assessed from satellite spectral measurements. The specific purpose of this experiment was to find out how well measurements of F sub ipar relate to ground, helicopter, and satellite based spectral reflectance measurements. Concurrent measurements of F sub ipar and ground, helicopter, and satellite based measurements were taken at 13 tall grass prairie sites in Kansas. The sites were subjected to various combinations of burning and grazing managements.

Catching What We Can't See: Manual Interception of Occluded Fly-Ball Trajectories

PubMed Central

Bosco, Gianfranco; Delle Monache, Sergio; Lacquaniti, Francesco

2012-01-01

Control of interceptive actions may involve fine interplay between feedback-based and predictive mechanisms. These processes rely heavily on target motion information available when the target is visible. However, short-term visual memory signals as well as implicit knowledge about the environment may also contribute to elaborate a predictive representation of the target trajectory, especially when visual feedback is partially unavailable because other objects occlude the visual target. To determine how different processes and information sources are integrated in the control of the interceptive action, we manipulated a computer-generated visual environment representing a baseball game. Twenty-four subjects intercepted fly-ball trajectories by moving a mouse cursor and by indicating the interception with a button press. In two separate sessions, fly-ball trajectories were either fully visible or occluded for 750, 1000 or 1250 ms before ball landing. Natural ball motion was perturbed during the descending trajectory with effects of either weightlessness (0 g) or increased gravity (2 g) at times such that, for occluded trajectories, 500 ms of perturbed motion were visible before ball disappearance. To examine the contribution of previous visual experience with the perturbed trajectories to the interception of invisible targets, the order of visible and occluded sessions was permuted among subjects. Under these experimental conditions, we showed that, with fully visible targets, subjects combined servo-control and predictive strategies. Instead, when intercepting occluded targets, subjects relied mostly on predictive mechanisms based, however, on different type of information depending on previous visual experience. In fact, subjects without prior experience of the perturbed trajectories showed interceptive errors consistent with predictive estimates of the ball trajectory based on a-priori knowledge of gravity. Conversely, the interceptive responses of subjects

Intercepting real and simulated falling objects: what is the difference?

PubMed

Baurès, Robin; Benguigui, Nicolas; Amorim, Michel-Ange; Hecht, Heiko

2009-10-30

The use of virtual reality is nowadays common in many studies in the field of human perception and movement control, particularly in interceptive actions. However, the ecological validity of the simulation is often taken for granted without having been formally established. If participants were to perceive the real situation and its virtual equivalent in a different fashion, the generalization of the results obtained in virtual reality to real life would be highly questionable. We tested the ecological validity of virtual reality in this context by comparing the timing of interceptive actions based upon actually falling objects and their simulated counterparts. The results show very limited differences as a function of whether participants were confronted with a real ball or a simulation thereof. And when present, such differences were limited to the first trial only. This result validates the use of virtual reality when studying interceptive actions of accelerated stimuli.

Modelling the control of interceptive actions.

PubMed Central

Beek, P J; Dessing, J C; Peper, C E; Bullock, D

2003-01-01

In recent years, several phenomenological dynamical models have been formulated that describe how perceptual variables are incorporated in the control of motor variables. We call these short-route models as they do not address how perception-action patterns might be constrained by the dynamical properties of the sensory, neural and musculoskeletal subsystems of the human action system. As an alternative, we advocate a long-route modelling approach in which the dynamics of these subsystems are explicitly addressed and integrated to reproduce interceptive actions. The approach is exemplified through a discussion of a recently developed model for interceptive actions consisting of a neural network architecture for the online generation of motor outflow commands, based on time-to-contact information and information about the relative positions and velocities of hand and ball. This network is shown to be consistent with both behavioural and neurophysiological data. Finally, some problems are discussed with regard to the question of how the motor outflow commands (i.e. the intended movement) might be modulated in view of the musculoskeletal dynamics. PMID:14561342

Exploring the potential of the cosmic-ray neutron method to measure interception storage dynamics

NASA Astrophysics Data System (ADS)

Jakobi, Jannis; Bogena, Heye; Huisman, Johan Alexander; Diekkrüger, Bernd; Vereecken, Harry

2017-04-01

Cosmic-ray neutron soil moisture probes are an emerging technology that relies on the negative correlation between near-surface fast neutron counts and soil moisture content. Hydrogen atoms in the soil, which are mainly present as water, moderate the secondary neutrons on the way back to the surface. Any application of this method needs to consider the sensitivity of the neutron counts to additional sources of hydrogen (e.g. above- and below-ground biomass, humidity of the lower atmosphere, lattice water of the soil minerals, organic matter and water in the litter layer, intercepted water in the canopy, and soil organic matter). In this study, we analyzed the effects of canopy-intercepted water on the cosmic-ray neutron counts. For this, an arable field cropped with sugar beet was instrumented with several cosmic-ray neutron probes and a wireless sensor network with more than 140 in-situ soil moisture sensors. Additionally rainfall interception was estimated using a new approach coupling throughfall measurements and leaf wetness sensors. The derived interception storage was used to correct for interception effects on cosmic ray neutrons to enhance soil water content prediction. Furthermore, the potential for a simultaneous prediction of above- and below-ground biomass, soil moisture and interception was tested.

Fog interception by Sequoia sempervirens (D. Don) crowns decouples physiology from soil water deficit.

PubMed

Simonin, Kevin A; Santiago, Louis S; Dawson, Todd E

2009-07-01

Although crown wetting events can increase plant water status, leaf wetting is thought to negatively affect plant carbon balance by depressing photosynthesis and growth. We investigated the influence of crown fog interception on the water and carbon relations of juvenile and mature Sequoia sempervirens trees. Field observations of mature trees indicated that fog interception increased leaf water potential above that of leaves sheltered from fog. Furthermore, observed increases in leaf water potential exceeded the maximum water potential predicted if soil water was the only available water source. Because field observations were limited to two mature trees, we conducted a greenhouse experiment to investigate how fog interception influences plant water status and photosynthesis. Pre-dawn and midday branchlet water potential, leaf gas exchange and chlorophyll fluorescence were measured on S. sempervirens saplings exposed to increasing soil water deficit, with and without overnight canopy fog interception. Sapling fog interception increased leaf water potential and photosynthesis above the control and soil water deficit treatments despite similar dark-acclimated leaf chlorophyll fluorescence. The field observations and greenhouse experiment show that fog interception represents an overlooked flux into the soil-plant-atmosphere continuum that temporarily, but significantly, decouples leaf-level water and carbon relations from soil water availability.

Bayesian Hierarchical Random Intercept Model Based on Three Parameter Gamma Distribution

NASA Astrophysics Data System (ADS)

Wirawati, Ika; Iriawan, Nur; Irhamah

2017-06-01

Hierarchical data structures are common throughout many areas of research. Beforehand, the existence of this type of data was less noticed in the analysis. The appropriate statistical analysis to handle this type of data is the hierarchical linear model (HLM). This article will focus only on random intercept model (RIM), as a subclass of HLM. This model assumes that the intercept of models in the lowest level are varied among those models, and their slopes are fixed. The differences of intercepts were suspected affected by some variables in the upper level. These intercepts, therefore, are regressed against those upper level variables as predictors. The purpose of this paper would demonstrate a proven work of the proposed two level RIM of the modeling on per capita household expenditure in Maluku Utara, which has five characteristics in the first level and three characteristics of districts/cities in the second level. The per capita household expenditure data in the first level were captured by the three parameters Gamma distribution. The model, therefore, would be more complex due to interaction of many parameters for representing the hierarchical structure and distribution pattern of the data. To simplify the estimation processes of parameters, the computational Bayesian method couple with Markov Chain Monte Carlo (MCMC) algorithm and its Gibbs Sampling are employed.

Marginal and Random Intercepts Models for Longitudinal Binary Data With Examples From Criminology.

PubMed

Long, Jeffrey D; Loeber, Rolf; Farrington, David P

2009-01-01

Two models for the analysis of longitudinal binary data are discussed: the marginal model and the random intercepts model. In contrast to the linear mixed model (LMM), the two models for binary data are not subsumed under a single hierarchical model. The marginal model provides group-level information whereas the random intercepts model provides individual-level information including information about heterogeneity of growth. It is shown how a type of numerical averaging can be used with the random intercepts model to obtain group-level information, thus approximating individual and marginal aspects of the LMM. The types of inferences associated with each model are illustrated with longitudinal criminal offending data based on N = 506 males followed over a 22-year period. Violent offending indexed by official records and self-report were analyzed, with the marginal model estimated using generalized estimating equations and the random intercepts model estimated using maximum likelihood. The results show that the numerical averaging based on the random intercepts can produce prediction curves almost identical to those obtained directly from the marginal model parameter estimates. The results provide a basis for contrasting the models and the estimation procedures and key features are discussed to aid in selecting a method for empirical analysis.

15 CFR 742.13 - Communications intercepting devices.

Code of Federal Regulations, 2010 CFR

2010-01-01

.... 742.13 Section 742.13 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade... POLICY-CCL BASED CONTROLS § 742.13 Communications intercepting devices. (a) License requirement. (1) In... Canada, for ECCNs having an “SL” under the “Reason for Control” paragraph. These items include any...

Suborbital Intercept and Fragmentation of an Asteroid with Very Short Warning Time Scenario

NASA Technical Reports Server (NTRS)

Hupp, Ryan; DeWald, Spencer; Wie, Bong; Barbee, Brent W.

2015-01-01

Small near-Earth objects (NEOs) is approx. 50-150 m in size are far more numerous (hundreds of thousands to millions yet to be discovered) than larger NEOs. Small NEOs, which are mostly asteroids rather than comets, are very faint in the night sky due to their small sizes, and are, therefore, difficult to discover far in advance of Earth impact. Furthermore, even small NEOs are capable of creating explosions with energies on the order of tens or hundreds of megatons (Mt). We are, therefore, motivated to prepare to respond effectively to short warning time, small NEO impact scenarios. In this paper we explore the lower bound on actionable warning time by investigating the performance of notional upgraded Intercontinental Ballistic Missiles (ICBMs) to carry Nuclear Explosive Device (NED) payloads to intercept and disrupt a hypothetical incoming NEO at high altitudes (generally at least 2500 km above Earth). We conduct this investigation by developing optimal NEO intercept trajectories for a range of cases and comparing their performances. Our results show that suborbital NEO intercepts using Minuteman III or SM-3 IIA launch vehicles could achieve NEO intercept a few minutes prior to when the NEO would strike Earth. We also find that more powerful versions of the launch vehicles (e.g., total deltaV is approx. 9.5-11 km/s) could intercept incoming NEOs several hours prior to when the NEO would strike Earth, if launched at least several days prior to the time of intercept. Finally, we discuss a number of limiting factors and practicalities that affect whether the notional systems we describe could become feasible.

Successful customer intercept interview recruitment outside small and midsize urban food retailers.

PubMed

Pelletier, Jennifer E; Caspi, Caitlin E; Schreiber, Liana R N; Erickson, Darin J; Harnack, Lisa; Laska, Melissa N

2016-10-05

Customer intercept interviews are increasingly used to characterize food purchases at retail food outlets and restaurants; however, methodological procedures, logistical issues and response rates using intercept methods are not well described in the food environment literature. The aims of this manuscript were to 1) describe the development and implementation of a customer intercept interview protocol in a large, NIH-funded study assessing food purchases in small and midsize food retailers in Minneapolis and St. Paul, Minnesota, 2) describe intercept interview response rates by store type and environmental factors (e.g., neighborhood socioeconomic status, day/time, weather), and 3) compare demographic characteristics (e.g., gender, race/ethnicity) of participants versus non-participants. After a pilot phase involving 28 stores, a total of 616 interviews were collected from customers exiting 128 stores in fall 2014. The number of eligible customers encountered per hour (a measure of store traffic), participants successfully recruited per hour, and response rates were calculated overall and by store type, neighborhood socio-economic status, day and time of data collection, and weather. Response rates by store type, neighborhood socio-economic status, time and day of data collection, and weather, and characteristics of participants and non-participants were compared using chi-square tests. The overall response rate was 35 %, with significantly higher response rates at corner/small grocery stores (47 %) and dollar stores (46 %) compared to food-gas marts (32 %) and pharmacies (26 %), and for data collection between 4:00-6:00 pm on weekdays (40 %) compared to weekends (32 %). The distribution of race/ethnicity, but not gender, differed between participants and non-participants (p < 0.01), with greater participation rates among those identified as Black versus White. Customer intercept interviews can be successfully used to recruit diverse samples of

Marginal and Random Intercepts Models for Longitudinal Binary Data with Examples from Criminology

ERIC Educational Resources Information Center

Long, Jeffrey D.; Loeber, Rolf; Farrington, David P.

2009-01-01

Two models for the analysis of longitudinal binary data are discussed: the marginal model and the random intercepts model. In contrast to the linear mixed model (LMM), the two models for binary data are not subsumed under a single hierarchical model. The marginal model provides group-level information whereas the random intercepts model provides…

A new terminal guidance sensor system for asteroid intercept or rendezvous missions

NASA Astrophysics Data System (ADS)

Lyzhoft, Joshua; Basart, John; Wie, Bong

2016-02-01

This paper presents the initial conceptual study results of a new terminal guidance sensor system for asteroid intercept or rendezvous missions, which explores the use of visual, infrared, and radar devices. As was demonstrated by NASA's Deep Impact mission, visual cameras can be effectively utilized for hypervelocity intercept terminal guidance for a 5 kilometer target. Other systems such as Raytheon's EKV (Exoatmospheric Kill Vehicle) employ a different scheme that utilizes infrared target information to intercept ballistic missiles. Another example that uses infrared information is the NEOWISE telescope, which is used for asteroid detection and tracking. This paper describes the signal-to-noise ratio estimation problem for infrared sensors, minimum and maximum range of detection, and computational validation using GPU accelerated simulations. Small targets (50-100 m in diameter) are considered, and scaled polyhedron models of known objects, such as the Rosetta mission's Comet 67P/Churyumov-Gerasimenko, 101,955 Bennu, target of the OSIRIS-REx mission, and asteroid 433 Eros, are utilized. A parallelized ray tracing algorithm to simulate realistic surface-to-surface shadowing of a given celestial body is developed. By using the simulated models and parameters given from the formulation of the different sensors, impact mission scenarios are used to verify the feasibility for intercepting a small target.

The influence of sugarcane crop development on rainfall interception losses

NASA Astrophysics Data System (ADS)

Fernandes, Rafael Pires; Silva, Robson Willians da Costa; Salemi, Luiz Felippe; Andrade, Tatiana Morgan Berteli de; Moraes, Jorge Marcos de; Dijk, Albert I. J. M. Van; Martinelli, Luiz Antonio

2017-08-01

The expansion of sugarcane plantations in Brazil has raised concerns regarding its hydrological impacts. One of these impacts is related to rainfall interception, which can be expected to vary in response to substantial changes in canopy structure throughout the cropping cycle. We collected field measurements to determine interception losses and interpreted the observations using an adapted Gash model during different stages of a sugarcane ratoon cropping cycle. Cumulative gross rainfall (PG), throughfall (TF) and stemflow (SF) were measured biweekly, along with vegetation structure measurements of leaf area index (LAI) and plant height. For the first 300 days after the first harvest, the cumulative PG of 1095 mm was partitioned into 635 mm TF (58%) and 263 mm SF (24%). The inferred interception loss (IL) was 263 mm (24%). There was a gradual and clear increase in IL from 3% to 46% while partitioning between TF and SF also changed during ratoon regrowth. After model parameter optimisation, observed IL was simulated satisfactorily. Model estimates suggested that evaporation from the saturated canopy is the main IL pathway, followed by evaporation after storms. Plant architecture, LAI and meteorological conditions during the cropping cycle appeared the main factors determining IL.

Effects of the interception of litterfall by the understory on carbon cycling in eucalyptus plantations of South China.

PubMed

Yang, Long; Wang, Jun; Huang, Yuhui; Hui, Dafeng; Wen, Meili

2014-01-01

For the purposes of forest restoration, carbon (C) fixation, and economic improvement, eucalyptus (Eucalyptus urophylla) has been widely planted in South China. The understory of eucalyptus plantations is often occupied by a dense community of the fern Dicranopteris dichotoma, which intercepts tree canopy leaf litter before it reaches the ground. To understand the effects of this interception of litterfall on C cycling in eucalyptus plantations, we quantified the mass of intercepted litter and the influences of litterfall interception on litter decomposition and soil respiration. The total mass of E. urophylla litterfall collected on the understory was similar to that collected by the traditional litter trap method. All of the eucalyptus litterfall is intercepted by the D. dichotoma canopy. Of the litterfall that was intercepted by D. dichotoma, 20-40% and 60-80% was intercepted by the top (50-100 cm) and bottom (0-50 cm) of the understory canopy, respectively. Intercepted litterfall decomposed faster at the bottom of understory canopy (at the base of the plants) than at the top, and decomposition was slower on the soil surface in the absence of understory than on any location in the understory canopy. Soil respiration was highest when both the understory and litter were present and was lowest when both the understory and litter were absent. These results indicate that litterfall interception changed carbon flow between aboveground and belowground through litter decomposition and soil respiration, which changed carbon cycling in eucalyptus plantations. The effects of the understory on litter decomposition and soil respiration should be considered in ecosystem carbon models.

Optimal feedback strategies for pursuit-evasion and interception in a plane

NASA Technical Reports Server (NTRS)

Rajan, N.; Ardema, M. D.

1983-01-01

Variable-speed pursuit-evasion and interception for two aircraft moving in a horizontal plane are analyzed in terms of a coordinate frame fixed in the plane at termination. Each participant's optimal motion can be represented by extremal trajectory maps. These maps are used to discuss sub-optimal approximations that are independent of the other participant. A method of constructing sections of the barrier, dispersal, and control-level surfaces and thus determining feedback strategies is described. Some examples are shown for pursuit-evasion and the minimum-time interception of a straight-flying target.

17 CFR 200.113 - Opportunity to respond; interception.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 17 Commodity and Securities Exchanges 2 2012-04-01 2012-04-01 false Opportunity to respond; interception. 200.113 Section 200.113 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION ORGANIZATION; CONDUCT AND ETHICS; AND INFORMATION AND REQUESTS Code of Behavior Governing Ex Parte...

17 CFR 200.113 - Opportunity to respond; interception.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 17 Commodity and Securities Exchanges 2 2013-04-01 2013-04-01 false Opportunity to respond; interception. 200.113 Section 200.113 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION ORGANIZATION; CONDUCT AND ETHICS; AND INFORMATION AND REQUESTS Code of Behavior Governing Ex Parte...

17 CFR 200.113 - Opportunity to respond; interception.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 17 Commodity and Securities Exchanges 2 2011-04-01 2011-04-01 false Opportunity to respond; interception. 200.113 Section 200.113 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION ORGANIZATION; CONDUCT AND ETHICS; AND INFORMATION AND REQUESTS Code of Behavior Governing Ex Parte...

17 CFR 200.113 - Opportunity to respond; interception.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 17 Commodity and Securities Exchanges 3 2014-04-01 2014-04-01 false Opportunity to respond; interception. 200.113 Section 200.113 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION ORGANIZATION; CONDUCT AND ETHICS; AND INFORMATION AND REQUESTS Code of Behavior Governing Ex Parte...

17 CFR 200.113 - Opportunity to respond; interception.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 17 Commodity and Securities Exchanges 2 2010-04-01 2010-04-01 false Opportunity to respond; interception. 200.113 Section 200.113 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION ORGANIZATION; CONDUCT AND ETHICS; AND INFORMATION AND REQUESTS Code of Behavior Governing Ex Parte...

Effects of the Interception of Litterfall by the Understory on Carbon Cycling in Eucalyptus Plantations of South China

PubMed Central

Huang, Yuhui; Hui, Dafeng; Wen, Meili

2014-01-01

For the purposes of forest restoration, carbon (C) fixation, and economic improvement, eucalyptus (Eucalyptus urophylla) has been widely planted in South China. The understory of eucalyptus plantations is often occupied by a dense community of the fern Dicranopteris dichotoma, which intercepts tree canopy leaf litter before it reaches the ground. To understand the effects of this interception of litterfall on C cycling in eucalyptus plantations, we quantified the mass of intercepted litter and the influences of litterfall interception on litter decomposition and soil respiration. The total mass of E. urophylla litterfall collected on the understory was similar to that collected by the traditional litter trap method. All of the eucalyptus litterfall is intercepted by the D. dichotoma canopy. Of the litterfall that was intercepted by D. dichotoma, 20–40% and 60–80% was intercepted by the top (50–100 cm) and bottom (0–50 cm) of the understory canopy, respectively. Intercepted litterfall decomposed faster at the bottom of understory canopy (at the base of the plants) than at the top, and decomposition was slower on the soil surface in the absence of understory than on any location in the understory canopy. Soil respiration was highest when both the understory and litter were present and was lowest when both the understory and litter were absent. These results indicate that litterfall interception changed carbon flow between aboveground and belowground through litter decomposition and soil respiration, which changed carbon cycling in eucalyptus plantations. The effects of the understory on litter decomposition and soil respiration should be considered in ecosystem carbon models. PMID:24959853

Interception in three dimensions - An energy formulation

NASA Technical Reports Server (NTRS)

Rajan, N.; Ardema, M. D.

1983-01-01

The problem of minimum-time interception of a target flying in three dimensional space is analyzed with the interceptor aircraft modeled through energy-state approximation. A coordinate transformation that uncouples the interceptor's extremals from the target motion in an open-loop sense is introduced, and the necessary conditions for optimality and the optimal controls are derived. Example extremals are shown.

Barriers and dispersal surfaces in minimum-time interception. [for optimizing aircraft flight paths

NASA Technical Reports Server (NTRS)

Rajan, N.; Ardema, M. D.

1984-01-01

A method is proposed for mapping the barrier, dispersal, and control-level surfaces for a class of minimum-time interception and pursuit-evasion problems. Minimum-time interception of a target moving in a horizontal plane is formulated in a coordinate system whose origin is at the interceptor's terminal position and whose x-axis is along the terminal line of sight. This approach makes it possible to discuss the nature of the interceptor's extremals, using its extremal trajectory maps (ETMs), independently of target motion. The game surfaces are constructed by drawing sections of the isochrones, or constant minimum-time loci, from the interceptor and target ETMs. In this way, feedback solutions for the optimal controls are obtained. An example involving the interception of a target moving in a straight line at constant speed is presented.

Calculation of intercepted runoff depth based on stormwater quality and environmental capacity of receiving waters for initial stormwater pollution management.

PubMed

Peng, Hai-Qin; Liu, Yan; Gao, Xue-Long; Wang, Hong-Wu; Chen, Yi; Cai, Hui-Yi

2017-11-01

While point source pollutions have gradually been controlled in recent years, the non-point source pollution problem has become increasingly prominent. The receiving waters are frequently polluted by the initial stormwater from the separate stormwater system and the wastewater from sewage pipes through stormwater pipes. Consequently, calculating the intercepted runoff depth has become a problem that must be resolved immediately for initial stormwater pollution management. The accurate calculation of intercepted runoff depth provides a solid foundation for selecting the appropriate size of intercepting facilities in drainage and interception projects. This study establishes a separate stormwater system for the Yishan Building watershed of Fuzhou City using the InfoWorks Integrated Catchment Management (InfoWorks ICM), which can predict the stormwater flow velocity and the flow of discharge outlet after each rainfall. The intercepted runoff depth is calculated from the stormwater quality and environmental capacity of the receiving waters. The average intercepted runoff depth from six rainfall events is calculated as 4.1 mm based on stormwater quality. The average intercepted runoff depth from six rainfall events is calculated as 4.4 mm based on the environmental capacity of the receiving waters. The intercepted runoff depth differs when calculated from various aspects. The selection of the intercepted runoff depth depends on the goal of water quality control, the self-purification capacity of the water bodies, and other factors of the region.

Rainfall interception, and its modeling, in Pine and Eucalypt stands in Portugal

NASA Astrophysics Data System (ADS)

de Coninck, H. L.; Keizer, J. J.; Coelho, C. O. A.; van Dijck, S. J. E.; Jetten, V. G.; Warmerdam, P. M. M.; Ferreira, A. J. D.; Boulet, A. K.

2003-04-01

Within the framework of the EU-funded CLIMED project (ICA3-2000-30005), concerning the water management implications of foreseeable climate and land-use changes in central Portugal and northern Africa, the event-based Limburg Soil Erosion Model (LISEM; www.geog.uu.nl/lisem) is intended to provide further insight into water yields, peak flow and timing under possible future rainfall regimes. In the Portuguese study area, LISEM is being applied to two small (< 1km2) catchments with contrasting land covers, dominated by Pinus pinaster Ait. and Eucalyptus globulus Labill. tree stands, respectively. In LISEM, cumulative interception is modelled using the empirical formula by Ashton (1979), i.e. as a function of vegetation cover and canopy storage capacity, which in turn is estimated from the Leaf Area Index using the Von Hoyningen-Huenes (1981) formula. Besides that the appropriateness of the LISEM interception module for forested areas may be questioned, its (optional) substitution in LISEM by a more process-based model like that of Rutter would be more in line with LISEM’s overall model structure. This study has as main aims to assess the suitability of (1) the Ashton formula and (2) the sparse variants of the Gash and Rutter interception models to model rainfall interception measurements carried out in a Pinus pinaster Ait. stand as well as a Eucalyptus globulus Labill. stand. Unlike in the bulk of published studies on forest interception, the experimental set-up structures the sampling space in below-canopy and gaps. The below-canopy sampling space is further divided into two classes on the basis of dendrometric data from a prior inventory of 20x20 m. The two stands are equipped with 15 below-canopy and 5 gap rainfall collectors, 3 of which are automated tipping-buckets gauges. Stemflow is measured for 10 trees per stand, which includes 2 trees with automated tipping-bucket (0.5 l/tip). Between November 2002 and the present time, 31 rainfall events totaling about

Eye movements in interception with delayed visual feedback.

PubMed

Cámara, Clara; de la Malla, Cristina; López-Moliner, Joan; Brenner, Eli

2018-07-01

The increased reliance on electronic devices such as smartphones in our everyday life exposes us to various delays between our actions and their consequences. Whereas it is known that people can adapt to such delays, the mechanisms underlying such adaptation remain unclear. To better understand these mechanisms, the current study explored the role of eye movements in interception with delayed visual feedback. In two experiments, eye movements were recorded as participants tried to intercept a moving target with their unseen finger while receiving delayed visual feedback about their own movement. In Experiment 1, the target randomly moved in one of two different directions at one of two different velocities. The delay between the participant's finger movement and movement of the cursor that provided feedback about the finger movements was gradually increased. Despite the delay, participants followed the target with their gaze. They were quite successful at hitting the target with the cursor. Thus, they moved their finger to a position that was ahead of where they were looking. Removing the feedback showed that participants had adapted to the delay. In Experiment 2, the target always moved in the same direction and at the same velocity, while the cursor's delay varied across trials. Participants still always directed their gaze at the target. They adjusted their movement to the delay on each trial, often succeeding to intercept the target with the cursor. Since their gaze was always directed at the target, and they could not know the delay until the cursor started moving, participants must have been using peripheral vision of the delayed cursor to guide it to the target. Thus, people deal with delays by directing their gaze at the target and using both experience from previous trials (Experiment 1) and peripheral visual information (Experiment 2) to guide their finger in a way that will make the cursor hit the target.

Deflection of the local interstellar dust flow by solar radiation pressure

NASA Technical Reports Server (NTRS)

Landgraf, M.; Augustsson, K.; Grun, E.; Gustafson, B. A.

1999-01-01

Interstellar dust grains intercepted by the dust detectors on the Ulysses and Galileo spacecrafts at heliocentric distances from 2 to 4 astronomical units show a deficit of grains with masses from 1 x 10(-17) to 3 x 10(-16) kilograms relative to grains intercepted outside 4 astronomical units. To divert grains out of the 2- to 4-astronomical unit region, the solar radiation pressure must be 1.4 to 1.8 times the force of solar gravity. These figures are consistent with the optical properties of spherical or elongated grains that consist of astronomical silicates or organic refractory material. Pure graphite grains with diameters of 0.2 to 0.4 micrometer experience a solar radiation pressure force as much as twice the force of solar gravity.

Description and Initial Evaluation of a Computer-Based Individual Trainer for the Radar Intercept Observer.

ERIC Educational Resources Information Center

Rigney, Joseph W.; And Others

An individual trainer for giving students in the radar intercept observer (RIO) schools concentrated practice in procedures for air-to-air intercepts was designed around a programmable graphics terminal with two integral minicomputers and 8k of core memory. The trainer automatically administers practice in computing values of variables in the…

An Efficient Ray-Tracing Method for Determining Terrain Intercepts in EDL Simulations

NASA Technical Reports Server (NTRS)

Shidner, Jeremy D.

2016-01-01

The calculation of a ray's intercept from an arbitrary point in space to a prescribed surface is a common task in computer simulations. The arbitrary point often represents an object that is moving according to the simulation, while the prescribed surface is fixed in a defined frame. For detailed simulations, this surface becomes complex, taking the form of real-world objects such as mountains, craters or valleys which require more advanced methods to accurately calculate a ray's intercept location. Incorporation of these complex surfaces has commonly been implemented in graphics systems that utilize highly optimized graphics processing units to analyze such features. This paper proposes a simplified method that does not require computationally intensive graphics solutions, but rather an optimized ray-tracing method for an assumed terrain dataset. This approach was developed for the Mars Science Laboratory mission which landed on the complex terrain of Gale Crater. First, this paper begins with a discussion of the simulation used to implement the model and the applicability of finding surface intercepts with respect to atmosphere modeling, altitude determination, radar modeling, and contact forces influencing vehicle dynamics. Next, the derivation and assumptions of the intercept finding method are presented. Key assumptions are noted making the routines specific to only certain types of surface data sets that are equidistantly spaced in longitude and latitude. The derivation of the method relies on ray-tracing, requiring discussion on the formulation of the ray with respect to the terrain datasets. Further discussion includes techniques for ray initialization in order to optimize the intercept search. Then, the model implementation for various new applications in the simulation are demonstrated. Finally, a validation of the accuracy is presented along with the corresponding data sets used in the validation. A performance summary of the method will be shown using

Quantifying dominance of intra-storm phase of interception process by small isolated canopies

NASA Astrophysics Data System (ADS)

Yerk, Walter; Montalto, Franco

2014-05-01

Precipitation interception by vegetation canopies has long been recognized as a major component of the hydrologic cycle; however, historically most research has been dedicated to closed or sparse canopy forests. The goal of our research was to quantify rainfall partitioning by small isolated canopies in an urban setting. The field experiment involved small forms of four shrub species (Prunus laurocerasus, Cornus sericea, Itea virginica and Hydrangea quercifolia) with crown heights 40 - 80 cm and diameters 35 - 60 cm. Each plant had ten rain gauges to measure throughfall with a sampling frequency of 5 seconds. An on-site automated weather station provided meteorological data. Leaf area index (LAI) was measured by manual counting. We estimated the canopy storage capacities of all four species to be less than 0.5 mm. The obtained data showed statistically significant differences in interception properties among all four species, except between Cornus and Itea. Cumulative interception loss for the period of August-December 2013 was 10% for Cornus, 16% for Itea, 29% for Hydrangea, and 49% for Prunus. The observations revealed a weak relationship between interception abilities and LAI for all four species. Throughfall and precipitation intensities (mm/hr) expressed very strong linear relationship (adjusted coefficients of determination were from 0.80 to 0.95) for the entire range of observed rainfall intensities. For Cornus the ratio of throughfall to precipitation intensity was close to 0.93:1, for Itea it was 0.82:1. The ratios were lesser for Hydrangea (0.65:1), and especially for Prunus (0.48:1). Therefore we show that reduced by the canopy, throughfall intensity results in the bulk of precipitation depth intercepted during the rain events. In contrast, the amount of water stored on the canopy and evaporated between and after rain events contributes minimally to interception. Simulations of potential evaporation based on the Penman-Monteith method showed a large

Altered Physiological Function, Not Structure, Drives Increased Radiation-Use Efficiency of Soybean Grown at Elevated CO2

USDA-ARS?s Scientific Manuscript database

Previous studies of elevated carbon dioxide concentration ([CO2]) on crop canopies have found that radiation-use efficiency is increased more than radiation-interception efficiency. It is assumed that increased radiation-use efficiency is due to changes in leaf-level physiology; however, canopy stru...

Radiation protection for manned space activities

NASA Technical Reports Server (NTRS)

Jordan, T. M.

1983-01-01

The Earth's natural radiation environment poses a hazard to manned space activities directly through biological effects and indirectly through effects on materials and electronics. The following standard practices are indicated that address: (1) environment models for all radiation species including uncertainties and temporal variations; (2) upper bound and nominal quality factors for biological radiation effects that include dose, dose rate, critical organ, and linear energy transfer variations; (3) particle transport and shielding methodology including system and man modeling and uncertainty analysis; (4) mission planning that includes active dosimetry, minimizes exposure during extravehicular activities, subjects every mission to a radiation review, and specifies operational procedures for forecasting, recognizing, and dealing with large solar flaes.

WATERSHED SCALE RAINFALL INTERCEPTION ON TWO FORESTED WATERSHEDS IN THE LUQUILLO MOUNTAINS OF PUERTO RICO

Treesearch

F.N. SCATENA

1990-01-01

Interception losses were monitored for one year and related to vegetation characteristics in two forested watersheds in the Luquillo Experimental Forest of Puerto Rico. Total watershed interception was then modeled by weighting values of throughfall measured in representative areas of different vegetation types by the total watershed area of that vegetation group....

Separation of Intercepted Multi-Radar Signals Based on Parameterized Time-Frequency Analysis

NASA Astrophysics Data System (ADS)

Lu, W. L.; Xie, J. W.; Wang, H. M.; Sheng, C.

2016-09-01

Modern radars use complex waveforms to obtain high detection performance and low probabilities of interception and identification. Signals intercepted from multiple radars overlap considerably in both the time and frequency domains and are difficult to separate with primary time parameters. Time-frequency analysis (TFA), as a key signal-processing tool, can provide better insight into the signal than conventional methods. In particular, among the various types of TFA, parameterized time-frequency analysis (PTFA) has shown great potential to investigate the time-frequency features of such non-stationary signals. In this paper, we propose a procedure for PTFA to separate overlapped radar signals; it includes five steps: initiation, parameterized time-frequency analysis, demodulating the signal of interest, adaptive filtering and recovering the signal. The effectiveness of the method was verified with simulated data and an intercepted radar signal received in a microwave laboratory. The results show that the proposed method has good performance and has potential in electronic reconnaissance applications, such as electronic intelligence, electronic warfare support measures, and radar warning.

Internal models of target motion: expected dynamics overrides measured kinematics in timing manual interceptions.

PubMed

Zago, Myrka; Bosco, Gianfranco; Maffei, Vincenzo; Iosa, Marco; Ivanenko, Yuri P; Lacquaniti, Francesco

2004-04-01

Prevailing views on how we time the interception of a moving object assume that the visual inputs are informationally sufficient to estimate the time-to-contact from the object's kinematics. Here we present evidence in favor of a different view: the brain makes the best estimate about target motion based on measured kinematics and an a priori guess about the causes of motion. According to this theory, a predictive model is used to extrapolate time-to-contact from expected dynamics (kinetics). We projected a virtual target moving vertically downward on a wide screen with different randomized laws of motion. In the first series of experiments, subjects were asked to intercept this target by punching a real ball that fell hidden behind the screen and arrived in synchrony with the visual target. Subjects systematically timed their motor responses consistent with the assumption of gravity effects on an object's mass, even when the visual target did not accelerate. With training, the gravity model was not switched off but adapted to nonaccelerating targets by shifting the time of motor activation. In the second series of experiments, there was no real ball falling behind the screen. Instead the subjects were required to intercept the visual target by clicking a mousebutton. In this case, subjects timed their responses consistent with the assumption of uniform motion in the absence of forces, even when the target actually accelerated. Overall, the results are in accord with the theory that motor responses evoked by visual kinematics are modulated by a prior of the target dynamics. The prior appears surprisingly resistant to modifications based on performance errors.

Evaporation of impact water droplets in interception processes: Historical precedence of the hypothesis and a brief literature overview

NASA Astrophysics Data System (ADS)

Dunkerley, David L.

2009-10-01

SummaryIntra-storm evaporation depths exceed post-storm evaporation depths in the interception of rainfall on plant canopies. An important fraction of the intra-storm evaporation may involve the small impact (or splash) droplets produced when raindrops, and perhaps gravity drops (drips released from plant parts), collide with wet plant surfaces. This idea has been presented as a new conception by Murakami [Murakami, S., 2006. A proposal for a new forest canopy interception mechanism: splash droplet evaporation. Journal of Hydrology 319, 72-82; Murakami, S., 2007a. Application of three canopy interception models to a young stand of Japanese cypress and interpretation in terms of interception mechanism. Journal of Hydrology 342, 305-319; Murakami, S., 2007b. A follow-up for the splash droplet evaporation hypothesis of canopy interception and remaining problems: why is humidity unsaturated during rainfall? In: Proceedings of the 20th Annual Conference. Japan Society of Hydrology and Water Resources (in Japanese). < http://www.jstage.jst.go.jp/article/jshwr/20/0/20_62/_article>] but was in fact advanced by Dunin [Dunin, F.X., O'Loughlin, E.M., Reyenga, W., 1988. Interception loss from eucalypt forest: lysimeter determination of hourly rates for long term evaluation. Hydrological Processes 2, 315-329] more than 20 years ago. In addition, Dunin et al. considered that canopy ventilation might be enhanced in intense rain. This note draws attention to the historical precedence of the work of Dunin et al. and also presents a short review of literature on impact droplet production, highlighting areas where data are still required for the full exploration of the role of droplet evaporation in canopy interception. Droplet production needs to be properly parameterised and included in models of interception processes and landsurface-atmosphere interactions.

New Hypervelocity Terminal Intercept Guidance Systems for Deflecting/Disrupting Hazardous Asteroids

NASA Astrophysics Data System (ADS)

Lyzhoft, Joshua Richard

Computational modeling and simulations of visual and infrared (IR) sensors are investigated for a new hypervelocity terminal guidance system of intercepting small asteroids (50 to 150 meters in diameter). Computational software tools for signal-to-noise ratio estimation of visual and IR sensors, estimation of minimum and maximum ranges of target detection, and GPU (Graphics Processing Units)-accelerated simulations of the IR-based terminal intercept guidance systems are developed. Scaled polyhedron models of known objects, such as the Rosetta mission's Comet 67P/C-G, NASA's OSIRIS-REx Bennu, and asteroid 433 Eros, are utilized in developing a GPU-based simulation tool for the IR-based terminal intercept guidance systems. A parallelized-ray tracing algorithm for simulating realistic surface-to-surface shadowing of irregular-shaped asteroids or comets is developed. Polyhedron solid-angle approximation is also considered. Using these computational models, digital image processing is investigated to determine single or multiple impact locations to assess the technical feasibility of new planetary defense mission concepts of utilizing a Hypervelocity Asteroid Intercept Vehicle (HAIV) or a Multiple Kinetic-energy Interceptor Vehicle (MKIV). Study results indicate that the IR-based guidance system outperforms the visual-based system in asteroid detection and tracking. When using an IR sensor, predicting impact locations from filtered images resulted in less jittery spacecraft control accelerations than conducting missions with a visual sensor. Infrared sensors have also the possibility to detect asteroids at greater distances, and if properly used, can aid in terminal phase guidance for proper impact location determination for the MKIV system. Emerging new topics of the Minimum Orbit Intersection Distance (MOID) estimation and the Full-Two-Body Problem (F2BP) formulation are also investigated to assess a potential near-Earth object collision risk and the proximity gravity

77 FR 18707 - USPS Package Intercept-New Product Offerings

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-28

... service that replaced the former recall of mail process. Plans were announced to implement new features.... Additionally, customers using the electronic process will have the option of adding selected extra services to... POSTAL SERVICE 39 CFR Part 111 USPS Package Intercept--New Product Offerings AGENCY: Postal...

The Chlamydial Inclusion Preferentially Intercepts Basolaterally Directed Sphingomyelin-Containing Exocytic Vacuoles

PubMed Central

Moore, Elizabeth R.; Fischer, Elizabeth R.; Mead, David J.; Hackstadt, Ted

2010-01-01

Chlamydiae replicate intracellularly within a unique vacuole termed the inclusion. The inclusion circumvents classical endosomal/lysosomal pathways but actively intercepts a subset of Golgi-derived exocytic vesicles containing sphingomyelin (SM) and cholesterol. To further examine this interaction, we developed a polarized epithelial cell model to study vectoral trafficking of lipids and proteins to the inclusion. We examined seven epithelial cell lines for their ability to form single monolayers of polarized cells and support chlamydial development. Of these cell lines, polarized colonic mucosal C2BBe1 cells were readily infected with Chlamydia trachomatis and remained polarized throughout infection. Trafficking of (6-((N-(7-nitrobenz-2-oxa-1, 3-diazol-4-yl) amino)hexanoyl)sphingosine) (NBD-C6-ceramide) and its metabolic derivatives, NBD-glucosylceramide (GlcCer) and NBD-SM, was analyzed. SM was retained within L2-infected cells relative to mock-infected cells, correlating with a disruption of basolateral SM trafficking. There was no net retention of GlcCer within L2-infected cells and purification of C. trachomatis elementary bodies from polarized C2BBe1 cells confirmed that bacteria retained only SM. The chlamydial inclusion thus appears to preferentially intercept basolaterally-directed SM-containing exocytic vesicles, suggesting a divergence in SM and GlcCer trafficking. The observed changes in lipid trafficking were a chlamydia-specific effect because Coxiella burnetii-infected cells revealed no changes in GlcCer or SM polarized trafficking. PMID:18778406

Process-based rainfall interception by small trees in Northern China: The effect of rainfall traits and crown structure characteristics

Treesearch

Xiang Li; Qingfu Xiao; Jianzhi Niu; Salli Dymond; Natalie S. van Doorn; Xinxiao Yu; Baoyuan Xie; Xizhi Lv; Kebin Zhang; Jiao Li

2016-01-01

Rainfall interception by a tree's crown is one of the most important hydrological processes in an ecosystem, yet the mechanisms of interception are not well understood. A process-based experiment was conducted under five simulated rainfall intensities (from 10 to 150 mm h−1) to directly quantify tree crown interception and examine the effect...

Measuring and modelling interception loss by an isolated olive tree in a traditional olive grove - pasture system

NASA Astrophysics Data System (ADS)

Nóbrega, Cristina; Pereira, Fernando L.; Valente, Fernanda

2015-04-01

Water losses associated to the rainfall interception process by trees can be an important component of the local hydrologic balance and must be accounted for when implementing any sustainable water management programme. In many dry areas of the Mediterranean region where agro-forestry systems are common, those programmes are crucial to foster adequate water conservation measures. Recent studies have shown that the evaluation of interception loss in sparse forests or tree plantations should be made for individual trees, being the total value determined as the sum of the individual contributions. Following this approach, rainfall interception was measured and modelled over two years, in an isolated Olea europeaea L. tree, in a traditional low-density olive grove in Castelo Branco, central Portugal. Total interception loss over the experimental period was 243.5 mm, on a tree crown projected area basis, corresponding to 18.0% of gross rainfall (Pg). Modelling made for each rainfall event using the sparse version of the Gash model, slightly underestimated interception loss with a value of 240.5 mm, i.e., 17.8 % ofPg. Modelling quality, evaluated according to a number of criteria, was good, allowing the conclusion that the methodology used was adequate. Modelling was also made on a daily basis, i.e., assuming a single storm per rainday. In this case, interception loss was overestimated by 12%, mostly because 72% of all rainfall events lasted for more than a day.

Variations in canopy and litter interception across a forest chronosequence in the southern Appalachian Mountains

Treesearch

Steven T. Brantley; Paul V. Bolstad; Stephanie H. Laseter; A. Christopher Oishi; Kimberly A. Novick; Chelcy F. Miniat

2016-01-01

Variations in evapotranspiration (ET) have been well documented across a variety of forest types and climates in recent decades; however, most of these data have focused on mature, secondgrowth stands. Here we present data on two important fluxes of water, canopy interception (Ic) and forest floor litter interception (Iff), across a chronosequence of forest age in the...

Time series of canopy intercepted water and dew observed in a tropical tree plantation by means of microwave radiometry

NASA Astrophysics Data System (ADS)

Schneebeli, M.; Wolf, S.; Kunert, N.; Eugster, W.; Mätzler, C.

2012-04-01

During summer and autumn 2007, a 11 GHz microwave radiometer was deployed in an experimental tree plantation in Sardinilla, Panama. With this instrument, the opacity of the tree canopy was derived from incoming brightness temperatures received on the ground. A collocated eddy-covariance flux tower measured water vapor fluxes and meteorological variables above the canopy. It was found that canopy intercepted rain and dew formation modulated the diurnal opacity cycle. With an enhanced canopy opacity model accounting for water deposited on the leaves, we quantified the influence of canopy stored water (i.e. intercepted water and dew) on the opacity. With this technique it was possible to directly monitor high resolution time series of dew formation and rain interception during a period of two weeks. In contrast to through-fall measurements, this new technique allows to determine the amount of intercepted rain more precisely and during day and night since evaporation effects do not hamper the accuracy of the method. We found that during light rainfall up to 60% of the rain amount is intercepted by the canopy whereas during periods of intense rainfall, only 4% were intercepted. On average, about 15% of the rain amount was intercepted during rainfalls of medium intensities. By comparing the interception with the water vapor flux time series it was found that intercepted water is evaporated rapidly after it is deposited on the leaves, which resulted in an enhanced water vapor flux. Our study also provides the first direct measurements and quantifications of the temporal evolution of dew formation and evaporation in a tree canopy on a diurnal base. Dew accumulated during the night and until about 2 h after sunrise, when the water vapor flux began to exceed the dew formation rate. The dew continued to evaporate for another 3.5 h until the surface of the leaves was completely dry. On average, 0.17 mm of dew was formed during the night. Dew evaporation contributed 5% to the

The dynamics of rainfall interception by a seasonal temperate rainforest.

Treesearch

Timothy E. Link; Mike Unsworth; Danny Marks

2004-01-01

Net canopy interception (Inet) during rainfall in an old-growth Douglas-fir-western hemlock ecosystem was 22.8 and 25.0% of the gross rainfall (PG) for 1999 and 2000, respectively. The average direct throughfall proportion (p) and canopy storage capacity (

A comparison of four-sample slope-intercept and single-sample 51Cr-EDTA glomerular filtration rate measurements.

PubMed

Porter, Charlotte A; Bradley, Kevin M; McGowan, Daniel R

2018-05-01

The aim of this study was to verify, with a large dataset of 1394 Cr-EDTA glomerular filtration rate (GFR) studies, the equivalence of slope-intercept and single-sample GFR. Raw data from 1394 patient studies were used to calculate four-sample slope-intercept GFR in addition to four individual single-sample GFR values (blood samples taken at 90, 150, 210 and 270 min after injection). The percentage differences between the four-sample slope-intercept and each of the single-sample GFR values were calculated, to identify the optimum single-sample time point. Having identified the optimum time point, the percentage difference between the slope-intercept and optimal single-sample GFR was calculated across a range of GFR values to investigate whether there was a GFR value below which the two methodologies cannot be considered equivalent. It was found that the lowest percentage difference between slope-intercept and single-sample GFR was for the third blood sample, taken at 210 min after injection. The median percentage difference was 2.5% and only 6.9% of patient studies had a percentage difference greater than 10%. Above a GFR value of 30 ml/min/1.73 m, the median percentage difference between the slope-intercept and optimal single-sample GFR values was below 10%, and so it was concluded that, above this value, the two techniques are sufficiently equivalent. This study supports the recommendation of performing single-sample GFR measurements for GFRs greater than 30 ml/min/1.73 m.

The relationship between energy expenditure and speed during pedestrian locomotion in birds: a morphological basis for the elevated y-intercept?

PubMed

Halsey, Lewis G

2013-06-01

The slope of the typically linear relationship between metabolic rate and walking speed represents the net cost of transport (NCOT). The extrapolated y-intercept is often greater than resting metabolic rate, thus representing a fixed cost associated with pedestrian transport including body maintenance costs. The full cause of the elevated y-intercept remains elusive and it could simply represent experimental stresses. The present literature-based study compares the mass-independent energetic cost of pedestrian locomotion in birds (excluding those with an upright posture, i.e. penguins), represented by the y-intercept, to a known predictor of cost of transport, hip height. Both phylogenetically informed and non-phylogenetically informed analyses were undertaken to determine if patterns of association between hip height, body mass, and the y-intercept are robust with respect to the method of analysis. Body mass and hip height were significant predictors of the y-intercept in the best phylogenetically-informed and non-phylogenetically informed models. Thus there is evidence that, in birds at least, the elevated y-intercept is a legitimate component of locomotion energy expenditure. Hip height is probably a good proxy of effective limb length and thus perhaps birds with greater hip heights have lower y-intercepts because their longer legs more efficiently accommodate body motion and/or because their limbs are more aligned with the ground reaction forces. Copyright © 2013 Elsevier Inc. All rights reserved.

Midday Depression vs. Midday Peak in Diurnal Light Interception: Contrasting Patterns at Crown and Leaf Scales in a Tropical Evergreen Tree.

PubMed

Ventre-Lespiaucq, Agustina; Flanagan, Nicola S; Ospina-Calderón, Nhora H; Delgado, Juan A; Escudero, Adrián

2018-01-01

Crown architecture usually is heterogeneous as a result of foraging in spatially and temporally heterogeneous light environments. Ecologists are only beginning to identify the importance of temporal heterogeneity for light acquisition in plants, especially at the diurnal scale. Crown architectural heterogeneity often leads to a diurnal variation in light interception. However, maximizing light interception during midday may not be an optimal strategy in environments with excess light. Instead, long-lived plants are expected to show crown architectures and leaf positions that meet the contrasting needs of light interception and avoidance of excess light on a diurnal basis. We expected a midday depression in the diurnal course of light interception both at the whole-crown and leaf scales, as a strategy to avoid the interception of excessive irradiance. We tested this hypothesis in a population of guava trees ( Psidium guajava L.) growing in an open tropical grassland. We quantified three crown architectural traits: intra-individual heterogeneity in foliage clumping, crown openness, and leaf position angles. We estimated the diurnal course of light interception at the crown scale using hemispheric photographs, and at the leaf scale using the cosine of solar incidence. Crowns showed a midday depression in light interception, while leaves showed a midday peak. These contrasting patterns were related to architectural traits. At the crown scale, the midday depression of light interception was linked to a greater crown openness and foliage clumping in crown tops than in the lateral parts of the crown. At the leaf scale, an average inclination angle of 45° led to the midday peak in light interception, but with a huge among-leaf variation in position angles. The mismatch in diurnal course of light interception at crown and leaf scales can indicate that different processes are being optimized at each scale. These findings suggest that the diurnal course of light interception

Midday Depression vs. Midday Peak in Diurnal Light Interception: Contrasting Patterns at Crown and Leaf Scales in a Tropical Evergreen Tree

PubMed Central

Ventre-Lespiaucq, Agustina; Flanagan, Nicola S.; Ospina-Calderón, Nhora H.; Delgado, Juan A.; Escudero, Adrián

2018-01-01

Crown architecture usually is heterogeneous as a result of foraging in spatially and temporally heterogeneous light environments. Ecologists are only beginning to identify the importance of temporal heterogeneity for light acquisition in plants, especially at the diurnal scale. Crown architectural heterogeneity often leads to a diurnal variation in light interception. However, maximizing light interception during midday may not be an optimal strategy in environments with excess light. Instead, long-lived plants are expected to show crown architectures and leaf positions that meet the contrasting needs of light interception and avoidance of excess light on a diurnal basis. We expected a midday depression in the diurnal course of light interception both at the whole-crown and leaf scales, as a strategy to avoid the interception of excessive irradiance. We tested this hypothesis in a population of guava trees (Psidium guajava L.) growing in an open tropical grassland. We quantified three crown architectural traits: intra-individual heterogeneity in foliage clumping, crown openness, and leaf position angles. We estimated the diurnal course of light interception at the crown scale using hemispheric photographs, and at the leaf scale using the cosine of solar incidence. Crowns showed a midday depression in light interception, while leaves showed a midday peak. These contrasting patterns were related to architectural traits. At the crown scale, the midday depression of light interception was linked to a greater crown openness and foliage clumping in crown tops than in the lateral parts of the crown. At the leaf scale, an average inclination angle of 45° led to the midday peak in light interception, but with a huge among-leaf variation in position angles. The mismatch in diurnal course of light interception at crown and leaf scales can indicate that different processes are being optimized at each scale. These findings suggest that the diurnal course of light interception

Finite-horizon differential games for missile-target interception system using adaptive dynamic programming with input constraints

NASA Astrophysics Data System (ADS)

Sun, Jingliang; Liu, Chunsheng

2018-01-01

In this paper, the problem of intercepting a manoeuvring target within a fixed final time is posed in a non-linear constrained zero-sum differential game framework. The Nash equilibrium solution is found by solving the finite-horizon constrained differential game problem via adaptive dynamic programming technique. Besides, a suitable non-quadratic functional is utilised to encode the control constraints into a differential game problem. The single critic network with constant weights and time-varying activation functions is constructed to approximate the solution of associated time-varying Hamilton-Jacobi-Isaacs equation online. To properly satisfy the terminal constraint, an additional error term is incorporated in a novel weight-updating law such that the terminal constraint error is also minimised over time. By utilising Lyapunov's direct method, the closed-loop differential game system and the estimation weight error of the critic network are proved to be uniformly ultimately bounded. Finally, the effectiveness of the proposed method is demonstrated by using a simple non-linear system and a non-linear missile-target interception system, assuming first-order dynamics for the interceptor and target.

Rapid design and optimization of low-thrust rendezvous/interception trajectory for asteroid deflection missions

NASA Astrophysics Data System (ADS)

Li, Shuang; Zhu, Yongsheng; Wang, Yukai

2014-02-01

Asteroid deflection techniques are essential in order to protect the Earth from catastrophic impacts by hazardous asteroids. Rapid design and optimization of low-thrust rendezvous/interception trajectories is considered as one of the key technologies to successfully deflect potentially hazardous asteroids. In this paper, we address a general framework for the rapid design and optimization of low-thrust rendezvous/interception trajectories for future asteroid deflection missions. The design and optimization process includes three closely associated steps. Firstly, shape-based approaches and genetic algorithm (GA) are adopted to perform preliminary design, which provides a reasonable initial guess for subsequent accurate optimization. Secondly, Radau pseudospectral method is utilized to transcribe the low-thrust trajectory optimization problem into a discrete nonlinear programming (NLP) problem. Finally, sequential quadratic programming (SQP) is used to efficiently solve the nonlinear programming problem and obtain the optimal low-thrust rendezvous/interception trajectories. The rapid design and optimization algorithms developed in this paper are validated by three simulation cases with different performance indexes and boundary constraints.

Muscular Proprioception Contributes to the Control of Interceptive Actions

ERIC Educational Resources Information Center

Bastin, Julien; Calvin, Sarah; Montagne, Gilles

2006-01-01

The authors proposed a model of the control of interceptive action over a ground plane (Chardenon, Montagne, Laurent, & Bootsma, 2004). This model is based on the cancellation of the rate of change of the angle between the current position of the target and the direction of displacement (i.e., the bearing angle). While several sources of visual…

Mission Design and Analysis for Suborbital Intercept and Fragmentation of an Asteroid with Very Short Warning Time

NASA Technical Reports Server (NTRS)

Hupp, Ryan; DeWald, Spencer; Wie, Bong; Barbee, Brent W.

2014-01-01

Small near-Earth objects (NEOs) approximately 50-150 m in size are far more numerous (hundreds of thousands to millions yet to be discovered) than larger NEOs. Small NEOs, which are mostly asteroids rather than comets, are very faint in the night sky due to their small sizes, and are, therefore, difficult to discover far in advance of Earth impact. Furthermore, even small NEOs are capable of creating explosions with energies on the order of tens or hundreds of megatons (Mt). We are, therefore, motivated to prepare to respond effectively to short warning time, small NEO impact scenarios. In this paper we explore the lower bound on actionable warning time by investigating the performance of notional upgraded Intercontinental Ballistic Missiles (ICBMs) to carry Nuclear Explosive Device (NED) payloads to intercept and disrupt a hypothetical incoming NEO at high altitudes (generally at least 2500 km above Earth). We conduct this investigation by developing optimal NEO intercept trajectories for a range of cases and comparing their performances. Our results show that suborbital NEO intercepts using Minuteman III or SM-3 IIA launch vehicles could achieve NEO intercept a few minutes prior to when the NEO would strike Earth. We also find that more powerful versions of the launch vehicles (e.g., total delta V of approximately 9.5-11 km/s) could intercept incoming NEOs several hours prior to when the NEO would strike Earth, if launched at least several days prior to the time of intercept. Finally, we discuss a number of limiting factors and practicalities that affect whether the notional systems we describe could become feasible.

Conceptual Design of a Hypervelocity Asteroid Intercept Vehicle (HAIV) Flight Validation Mission

NASA Technical Reports Server (NTRS)

Barbee, Brent W.; Wie, Bong; Steiner, Mark; Getzandanner, Kenneth

2013-01-01

In this paper we present a detailed overview of the MDL study results and subsequent advances in the design of GNC algorithms for accurate terminal guidance during hypervelocity NEO intercept. The MDL study produced a conceptual con guration of the two-body HAIV and its subsystems; a mission scenario and trajectory design for a notional flight validation mission to a selected candidate target NEO; GNC results regarding the ability of the HAIV to reliably intercept small (50 m) NEOs at hypervelocity (typically greater than 10 km/s); candidate launch vehicle selection; a notional operations concept and cost estimate for the flight validation mission; and a list of topics to address during the remainder of our NIAC Phase II study.

The perceptual control of goal-directed locomotion: a common control architecture for interception and navigation?

PubMed

Chardenon, A; Montagne, G; Laurent, M; Bootsma, R J

2004-09-01

Intercepting a moving object while locomoting is a highly complex and demanding ability. Notwithstanding the identification of several informational candidates, the role of perceptual variables in the control process underlying such skills remains an open question. In this study we used a virtual reality set-up for studying locomotor interception of a moving ball. The subject had to walk along a straight path and could freely modify forward velocity, if necessary, in order to intercept-with the head-a ball moving along a straight path that led it to cross the agent's displacement axis. In a series of experiments we manipulated a local (ball size) and a global (focus of expansion) component of the visual flow but also the egocentric orientation of the ball. The experimental observations are well captured by a dynamic model linking the locomotor acceleration to properties of both global flow and egocentric direction. More precisely the changes in locomotor velocity depend on a linear combination of the change in bearing angle and the change in egocentric orientation, allowing the emergence of adaptive behavior under a variety of circumstances. We conclude that the mechanisms underlying the control of different goal-directed locomotion tasks (i.e. steering and interceptive tasks) could share a common architecture.

When up is down in 0g: how gravity sensing affects the timing of interceptive actions.

PubMed

Senot, Patrice; Zago, Myrka; Le Séac'h, Anne; Zaoui, Mohammed; Berthoz, Alain; Lacquaniti, Francesco; McIntyre, Joseph

2012-02-08

Humans are known to regulate the timing of interceptive actions by modeling, in a simplified way, Newtonian mechanics. Specifically, when intercepting an approaching ball, humans trigger their movements a bit earlier when the target arrives from above than from below. This bias occurs regardless of the ball's true kinetics, and thus appears to reflect an a priori expectation that a downward moving object will accelerate. We postulate that gravito-inertial information is used to tune visuomotor responses to match the target's most likely acceleration. Here we used the peculiar conditions of parabolic flight--where gravity's effects change every 20 s--to test this hypothesis. We found a striking reversal in the timing of interceptive responses performed in weightlessness compared with trials performed on ground, indicating a role of gravity sensing in the tuning of this response. Parallels between these observations and the properties of otolith receptors suggest that vestibular signals themselves might plausibly provide the critical input. Thus, in addition to its acknowledged importance for postural control, gaze stabilization, and spatial navigation, we propose that detecting the direction of gravity's pull plays a role in coordinating quick reactions intended to intercept a fast-moving visual target.

Radiation pressure: A possible cause for the superrotation of the Venusian atmosphere

NASA Technical Reports Server (NTRS)

Krause, J. L.

1992-01-01

The superrotation of the venusian atmosphere relative to the planet's surface has long been known. Yet the process by which this vigorous circulation is maintained is poorly understood. The purpose of this report is to show that a mechanism by which the solar radiation interacts with the cloudy atmosphere of Venus could be the principle cause of the superrotation. It has been long known that Venus has a high albedo due to the scattering (similar to the reflection process) of solar radiation by the cloud droplets in its atmosphere. The radiation not scattered, but intercepted by the planet and its atmosphere, is mainly absorbed within the cloud layers. Therefore, momentum (equal, more or less, to that of the solar radiation intercepted) is continually transferred to the venusian atmosphere. The atmospheric system presents a symmetrical surface (same radiation-matter interaction) toward the solar radiation at its morning and evening limbs. If the cross-sectional areas at both limbs were equal, the momentum transfer at the morning limb would decelerate the atmosphere's rotation while at the evening limb the same transfer would accelerate the rotation an equal amount. The net result of this is that the overall rate of rotation would be unchanged. Such a symmetrical configuration is not likely since the atmosphere must be warmed as it rotates across the planet's day hemisphere and cooled as it rotates across the planet's night hemisphere. This warming and cooling must result in a formation of an asymmetrical configuration. It is apparent that the momentum transfer at the evening limb must be greater than that at the morning limb because the atmosphere's greater cross section at the evening limb intercepts a greater amount of solar radiation. It should be noted that very little of the solar radiation is transmitted through the cloud layers, especially at or near the limbs where the atmospheric path length of the radiation is long. This net momentum transfer must be

Plant light interception can be explained via computed tomography scanning: demonstration with pyramidal cedar (Thuja occidentalis, Fastigiata).

PubMed

Dutilleul, Pierre; Han, Liwen; Smith, Donald L

2008-01-01

Light interception by the leaf canopy is a key aspect of plant photosynthesis, which helps mitigate the greenhouse effect via atmospheric CO(2) recycling. The relationship between plant light interception and leaf area was traditionally modelled with the Beer-Lambert law, until the spatial distribution of leaves was incorporated through the fractal dimension of leafless plant structure photographed from the side allowing maximum appearance of branches and petioles. However, photographs of leafless plants are two-dimensional projections of three-dimensional structures, and sampled plants were cut at the stem base before leaf blades were detached manually, so canopy development could not be followed for individual plants. Therefore, a new measurement and modelling approach were developed to explain plant light interception more completely and precisely, based on appropriate processing of computed tomography (CT) scanning data collected for developing canopies. Three-dimensional images of canopies were constructed from CT scanning data. Leaf volumes (LV) were evaluated from complete canopy images, and fractal dimensions (FD) were estimated from skeletonized leafless images. The experimental plant species is pyramidal cedar (Thuja occidentalis, Fastigiata). The three-dimensional version of the Beer-Lambert law based on FD alone provided a much better explanation of plant light interception (R(2) = 0.858) than those using the product LV*FD (0.589) or LV alone (0.548). While values of all three regressors were found to increase over time, FD in the Beer-Lambert law followed the increase in light interception the most closely. The delayed increase of LV reflected the appearance of new leaves only after branches had lengthened and ramified. The very strong correlation obtained with FD demonstrates that CT scanning data contain fundamental information about the canopy architecture geometry. The model can be used to identify crops and plantation trees with improved light

Traveler information services in rural tourism areas : appendix A, tourist intercept surveys

DOT National Transportation Integrated Search

2000-06-30

This document presents documentation regarding tourist intercept surveys for traveler information services in rural areas. It documents data collection functions and information dissemination functions, and provides an interpretive description of tra...

Exploring the spatial distribution of light interception and photosynthesis of canopies by means of a functional-structural plant model.

PubMed

Sarlikioti, V; de Visser, P H B; Marcelis, L F M

2011-04-01

At present most process-based models and the majority of three-dimensional models include simplifications of plant architecture that can compromise the accuracy of light interception simulations and, accordingly, canopy photosynthesis. The aim of this paper is to analyse canopy heterogeneity of an explicitly described tomato canopy in relation to temporal dynamics of horizontal and vertical light distribution and photosynthesis under direct- and diffuse-light conditions. Detailed measurements of canopy architecture, light interception and leaf photosynthesis were carried out on a tomato crop. These data were used for the development and calibration of a functional-structural tomato model. The model consisted of an architectural static virtual plant coupled with a nested radiosity model for light calculations and a leaf photosynthesis module. Different scenarios of horizontal and vertical distribution of light interception, incident light and photosynthesis were investigated under diffuse and direct light conditions. Simulated light interception showed a good correspondence to the measured values. Explicitly described leaf angles resulted in higher light interception in the middle of the plant canopy compared with fixed and ellipsoidal leaf-angle distribution models, although the total light interception remained the same. The fraction of light intercepted at a north-south orientation of rows differed from east-west orientation by 10 % on winter and 23 % on summer days. The horizontal distribution of photosynthesis differed significantly between the top, middle and lower canopy layer. Taking into account the vertical variation of leaf photosynthetic parameters in the canopy, led to approx. 8 % increase on simulated canopy photosynthesis. Leaf angles of heterogeneous canopies should be explicitly described as they have a big impact both on light distribution and photosynthesis. Especially, the vertical variation of photosynthesis in canopy is such that the

Exploring the spatial distribution of light interception and photosynthesis of canopies by means of a functional–structural plant model

PubMed Central

Sarlikioti, V.; de Visser, P. H. B.; Marcelis, L. F. M.

2011-01-01

Background and Aims At present most process-based models and the majority of three-dimensional models include simplifications of plant architecture that can compromise the accuracy of light interception simulations and, accordingly, canopy photosynthesis. The aim of this paper is to analyse canopy heterogeneity of an explicitly described tomato canopy in relation to temporal dynamics of horizontal and vertical light distribution and photosynthesis under direct- and diffuse-light conditions. Methods Detailed measurements of canopy architecture, light interception and leaf photosynthesis were carried out on a tomato crop. These data were used for the development and calibration of a functional–structural tomato model. The model consisted of an architectural static virtual plant coupled with a nested radiosity model for light calculations and a leaf photosynthesis module. Different scenarios of horizontal and vertical distribution of light interception, incident light and photosynthesis were investigated under diffuse and direct light conditions. Key Results Simulated light interception showed a good correspondence to the measured values. Explicitly described leaf angles resulted in higher light interception in the middle of the plant canopy compared with fixed and ellipsoidal leaf-angle distribution models, although the total light interception remained the same. The fraction of light intercepted at a north–south orientation of rows differed from east–west orientation by 10 % on winter and 23 % on summer days. The horizontal distribution of photosynthesis differed significantly between the top, middle and lower canopy layer. Taking into account the vertical variation of leaf photosynthetic parameters in the canopy, led to approx. 8 % increase on simulated canopy photosynthesis. Conclusions Leaf angles of heterogeneous canopies should be explicitly described as they have a big impact both on light distribution and photosynthesis. Especially, the vertical

Near-Earth Object Interception Using Nuclear Thermal Rock Propulsion

DOE Office of Scientific and Technical Information (OSTI.GOV)

X-L. Zhang; E. Ball; L. Kochmanski

Planetary defense has drawn wide study: despite the low probability of a large-scale impact, its consequences would be disastrous. The study presented here evaluates available protection strategies to identify bottlenecks limiting the scale of near-Earth object that could be deflected, using cutting-edge and near-future technologies. It discusses the use of a nuclear thermal rocket (NTR) as a propulsion device for delivery of thermonuclear payloads to deflect or destroy a long-period comet on a collision course with Earth. A ‘worst plausible scenario’ for the available warning time (10 months) and comet approach trajectory are determined, and empirical data are used tomore » make an estimate of the payload necessary to deflect such a comet. Optimizing the tradeoff between early interception and large deflection payload establishes the ideal trajectory for an interception mission to follow. The study also examines the potential for multiple rocket launch dates. Comparison of propulsion technologies for this mission shows that NTR outperforms other options substantially. The discussion concludes with an estimate of the comet size (5 km) that could be deflected usingNTRpropulsion, given current launch capabilities.« less

Intercepted signals for ionospheric science

NASA Astrophysics Data System (ADS)

Lind, F. D.; Erickson, P. J.; Coster, A. J.; Foster, J. C.; Marchese, J. R.; Berkowitz, Z.; Sahr, J. D.

2013-05-01

The ISIS array (Intercepted Signals for Ionospheric Science) is a distributed, coherent software radio array designed for the study of geospace phenomena by observing the scatter of ambient radio frequency (RF) signals. ISIS data acquisition and analysis is performed using the MIDAS-M platform (Millstone Data Acquisition System - Mobile). Observations of RF signals can be performed between HF and L-band using the Array nodes and appropriate antennas. The deployment of the Array focuses on observations of the plasmasphere boundary layer. We discuss the concept of the coherent software radio array, describe the ISIS hardware, and give examples of data from the system for selected applications. In particular, we include the first observations of E region irregularities using the Array. We also present single-site passive radar observations of both meteor trails and E region irregularities using adaptive filtering techniques.

Echolocating bats use a nearly time-optimal strategy to intercept prey.

PubMed

Ghose, Kaushik; Horiuchi, Timothy K; Krishnaprasad, P S; Moss, Cynthia F

2006-05-01

Acquisition of food in many animal species depends on the pursuit and capture of moving prey. Among modern humans, the pursuit and interception of moving targets plays a central role in a variety of sports, such as tennis, football, Frisbee, and baseball. Studies of target pursuit in animals, ranging from dragonflies to fish and dogs to humans, have suggested that they all use a constant bearing (CB) strategy to pursue prey or other moving targets. CB is best known as the interception strategy employed by baseball outfielders to catch ballistic fly balls. CB is a time-optimal solution to catch targets moving along a straight line, or in a predictable fashion--such as a ballistic baseball, or a piece of food sinking in water. Many animals, however, have to capture prey that may make evasive and unpredictable maneuvers. Is CB an optimum solution to pursuing erratically moving targets? Do animals faced with such erratic prey also use CB? In this paper, we address these questions by studying prey capture in an insectivorous echolocating bat. Echolocating bats rely on sonar to pursue and capture flying insects. The bat's prey may emerge from foliage for a brief time, fly in erratic three-dimensional paths before returning to cover. Bats typically take less than one second to detect, localize and capture such insects. We used high speed stereo infra-red videography to study the three dimensional flight paths of the big brown bat, Eptesicus fuscus, as it chased erratically moving insects in a dark laboratory flight room. We quantified the bat's complex pursuit trajectories using a simple delay differential equation. Our analysis of the pursuit trajectories suggests that bats use a constant absolute target direction strategy during pursuit. We show mathematically that, unlike CB, this approach minimizes the time it takes for a pursuer to intercept an unpredictably moving target. Interestingly, the bat's behavior is similar to the interception strategy implemented in some

Pink Cricket Balls Through Rose-Tinted Glasses: Enhancing Interceptive Timing

PubMed Central

Adie, Joshua M.

2017-01-01

Cricket is a popular but potentially dangerous sport. It is played with a hard ball that can travel at great speeds. Serious injuries, including fatalities, have occurred when balls have struck participants. The game is traditionally played during daylight with a dark red ball, but recent games have been played during the day and at night using a ‘pink’ ball. We have reported data that seemed to justify concerns raised regarding the visibility of these new pink balls, as they were revealed to have a very low luminance contrast against pertinent backgrounds during twilight. Here, we report on the findings of a psychophysical experiment, wherein we mimicked twilight lighting conditions in an interceptive timing experiment using a pink moving disc as an analogue for pink cricket balls. We show that interceptive timing performance is diminished in conditions that mimic twilight. More importantly, we show that wearing glasses with a rose-tinted filter can alleviate this adverse impact by enhancing the luminance contrast of the pink ‘ball’ relative to pertinent backgrounds. PMID:29225767

Small Active Radiation Monitor

NASA Technical Reports Server (NTRS)

Badhwar, Gautam D.

2004-01-01

A device, named small active radiation monitor, allows on-orbit evaluations during periods of increased radiation, after extravehicular activities, or at predesignated times for crews on such long-duration space missions as on the International Space Station. It also permits direct evaluation of biological doses, a task now performed using a combination of measurements and potentially inaccurate simulations. Indeed the new monitor can measure a full array of radiation levels, from soft x-rays to hard galactic cosmic-ray particles. With refinement, it will benefit commercial (nuclear power-plant workers, airline pilots, medical technicians, physicians/dentists, and others) and military personnel as well as the astronauts for whom thermoluminescent dosimeters are inadequate. Civilian and military personnel have long since graduated from film badges to thermoluminescent dosimeters. Once used, most dosimeters must be returned to a central facility for processing, a step that can take days or even weeks. While this suffices for radiation workers for whom exposure levels are typically very low and of brief duration, it does not work for astronauts. Even in emergencies and using express mail, the results can often be delayed by as much as 24 hours. Electronic dosimeters, which are the size of electronic oral thermometers, and tattlers, small electronic dosimeters that sound an alarm when the dose/dose rate exceeds preset values, are also used but suffer disadvantages similar to those of thermoluminescent dosimeters. None of these devices fully answers the need of rapid monitoring during the space missions. Instead, radiation is monitored by passive detectors, which are read out after the missions. Unfortunately, these detectors measure only the absorbed dose and not the biologically relevant dose equivalent. The new monitor provides a real-time readout, a time history of radiation exposures (both absorbed dose and biologically relevant dose equivalent), and a count of the

Interception of moving objects while walking in children with spastic hemiparetic cerebral palsy.

PubMed

Ricken, Annieck X C; Savelsbergh, G J P; Bennett, S J

2007-01-15

The purpose of the study was to examine the coordination of reaching and walking behaviour when children with Spastic Hemiparetic Cerebral Palsy (SHCP) intercept an approaching and hence externally-timed object. Using either the impaired or non-impaired arm, children intercepted a ball approaching from a fixed distance with one of three velocities. Each participant's initial starting position was scaled to their maximum walking velocity determined prior to testing; for the medium ball velocity, participants would arrive at the point of interception at the correct time if they walked with their maximum velocity. Children with SHCP adapted their reaching and walking behaviour to the different ball approach velocities. These adaptations were exhibited when using the impaired and non-impaired arm, and resulted in similar outcome performance irrespective of which arm was used. Still, children with SHCP found it necessary to increase trunk movement to compensate for the decreased elbow excursion and a decreased peak velocity of the impaired arm. Children with SHCP exhibited specific adaptations to their altered movement capabilities when performing a behaviourally-realistic task. The provision of an external timing constraint appeared to facilitate both reaching and walking movements and hence could represent a useful technique in rehabilitation.

Interception of rainfall in a young loblolly pine plantation

Treesearch

Marvin D. Hoover

1953-01-01

Those who have sought refuge during a storm have found a tree to be an effective umbrella for a light shower but leaky in a heavy rain. Even so, it is usually possible to stay slightly more dry under forest canopy than in the open. That is because a portion of the rain is stored on leaves and branches and eventually evaporated back to the air. The term interception is...

Rainfall Interception by Hardwood Forest Litter in the Southern Appalachians

Treesearch

J.D. Helvey

1964-01-01

The portion of rainfall over forest cover which does not reach mineral soil can be separated into the parts evaporated from the canopy and from the litter. Canopy interception loss is usually estimated by subtracting the sum of throughfall (water falling through tree crowns) and stemflow (water running down stems) from rainfall measured in forest openings (Hamilton...

Plant Light Interception Can Be Explained via Computed Tomography Scanning: Demonstration with Pyramidal Cedar (Thuja occidentalis, Fastigiata)

PubMed Central

Dutilleul, Pierre; Han, Liwen; Smith, Donald L.

2008-01-01

Background and Aims Light interception by the leaf canopy is a key aspect of plant photosynthesis, which helps mitigate the greenhouse effect via atmospheric CO2 recycling. The relationship between plant light interception and leaf area was traditionally modelled with the Beer–Lambert law, until the spatial distribution of leaves was incorporated through the fractal dimension of leafless plant structure photographed from the side allowing maximum appearance of branches and petioles. However, photographs of leafless plants are two-dimensional projections of three-dimensional structures, and sampled plants were cut at the stem base before leaf blades were detached manually, so canopy development could not be followed for individual plants. Therefore, a new measurement and modelling approach were developed to explain plant light interception more completely and precisely, based on appropriate processing of computed tomography (CT) scanning data collected for developing canopies. Methods Three-dimensional images of canopies were constructed from CT scanning data. Leaf volumes (LV) were evaluated from complete canopy images, and fractal dimensions (FD) were estimated from skeletonized leafless images. The experimental plant species is pyramidal cedar (Thuja occidentalis, Fastigiata). Key Results The three-dimensional version of the Beer–Lambert law based on FD alone provided a much better explanation of plant light interception (R2 = 0·858) than those using the product LV*FD (0·589) or LV alone (0·548). While values of all three regressors were found to increase over time, FD in the Beer–Lambert law followed the increase in light interception the most closely. The delayed increase of LV reflected the appearance of new leaves only after branches had lengthened and ramified. Conclusions The very strong correlation obtained with FD demonstrates that CT scanning data contain fundamental information about the canopy architecture geometry. The model can be used to

Interceptive Beam Diagnostics - Signal Creation and Materials Interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plum, Michael; Spallation Neutron Source, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN

2004-11-10

The focus of this tutorial will be on interceptive beam diagnostics such as wire scanners, screens, and harps. We will start with an overview of the various ways beams interact with materials to create signals useful for beam diagnostics systems. We will then discuss the errors in a harp or wire scanner profile measurement caused by errors in wire position, number of samples, and signal errors. Finally we will apply our results to two design examples-the SNS wire scanner system and the SNS target harp.

Mean-intercept anisotropy analysis of porous media. II. Conceptual shortcomings of the MIL tensor definition and Minkowski tensors as an alternative.

PubMed

Klatt, Michael A; Schröder-Turk, Gerd E; Mecke, Klaus

2017-07-01

Structure-property relations, which relate the shape of the microstructure to physical properties such as transport or mechanical properties, need sensitive measures of structure. What are suitable fabric tensors to quantify the shape of anisotropic heterogeneous materials? The mean intercept length is among the most commonly used characteristics of anisotropy in porous media, e.g., of trabecular bone in medical physics. Yet, in this series of two papers we demonstrate that it has conceptual shortcomings that limit the validity of its results. We test the validity of general assumptions regarding the properties of the mean-intercept length tensor using analytical formulas for the mean-intercept lengths in anisotropic Boolean models (derived in part I of this series), augmented by numerical simulations. We discuss in detail the functional form of the mean intercept length as a function of the test line orientations. As the most prominent result, we find that, at least for the example of overlapping grains modeling porous media, the polar plot of the mean intercept length is in general not an ellipse and hence not represented by a second-rank tensor. This is in stark contrast to the common understanding that for a large collection of grains the mean intercept length figure averages to an ellipse. The standard mean intercept length tensor defined by a least-square fit of an ellipse is based on a model mismatch, which causes an intrinsic lack of accuracy. Our analysis reveals several shortcomings of the mean intercept length tensor analysis that pose conceptual problems and limitations on the information content of this commonly used analysis method. We suggest the Minkowski tensors from integral geometry as alternative sensitive measures of anisotropy. The Minkowski tensors allow for a robust, comprehensive, and systematic approach to quantify various aspects of structural anisotropy. We show the Minkowski tensors to be more sensitive, in the sense, that they can

Interoperability In Multi-Layered Active Defense:The Need For Commonality And Robustness Between Active Defense Weapon Systems

DTIC Science & Technology

2016-02-16

into areas where there is no access to maritime platforms. Sea-based interceptor platforms have the ability to intercept targets at each stage of the...argues that the most efficient concept for integrating active defense weapon systems is a multi- layered architecture with redundant intercept ...faster data transfer and will prevent data loss. The need for almost 100% interception successes is increasing as the threat becomes more

Classification of Snowfall Events and Their Effect on Canopy Interception Efficiency in a Temperate Montane Forest.

NASA Astrophysics Data System (ADS)

Roth, T. R.; Nolin, A. W.

2015-12-01

Forest canopies intercept as much as 60% of snowfall in maritime environments, while processes of sublimation and melt can reduce the amount of snow transferred from the canopy to the ground. This research examines canopy interception efficiency (CIE) as a function of forest and event-scale snowfall characteristics. We use a 4-year dataset of continuous meteorological measurements and monthly snow surveys from the Forest Elevation Snow Transect (ForEST) network that has forested and open sites at three elevations spanning the rain-snow transition zone to the upper seasonal snow zone. Over 150 individual storms were classified by forest and storm type characteristics (e.g. forest density, vegetation type, air temperature, snowfall amount, storm duration, wind speed, and storm direction). The between-site comparisons showed that, as expected, CIE was highest for the lower elevation (warmer) sites with higher forest density compared with the higher elevation sites where storm temperatures were colder, trees were smaller and forests were less dense. Within-site comparisons based on storm type show that this classification system can be used to predict CIE.Our results suggest that the coupling of forest type and storm type information can improve estimates of canopy interception. Understanding the effects of temperature and storm type in temperate montane forests is also valuable for future estimates of canopy interception under a warming climate.

Development of a table tennis robot for ball interception using visual feedback

NASA Astrophysics Data System (ADS)

Parnichkun, Manukid; Thalagoda, Janitha A.

2016-07-01

This paper presents a concept of intercepting a moving table tennis ball using a robot. The robot has four degrees of freedom(DOF) which are simplified in such a way that The system is able to perform the task within the bounded limit. It employs computer vision to localize the ball. For ball identification, Colour Based Threshold Segmentation(CBTS) and Background Subtraction(BS) methodologies are used. Coordinate Transformation(CT) is employed to transform the data, which is taken based on camera coordinate frame to the general coordinate frame. The sensory system consisted of two HD Web Cameras. The computation time of image processing from web cameras is long .it is not possible to intercept table tennis ball using only image processing. Therefore the projectile motion model is employed to predict the final destination of the ball.

Satellite-based prediction of rainfall interception by tropical forest stands of a human-dominated landscape in Central Sulawesi, Indonesia

NASA Astrophysics Data System (ADS)

Nieschulze, Jens; Erasmi, Stefan; Dietz, Johannes; Hölscher, Dirk

2009-01-01

SummaryRainforest conversion to other land use types drastically alters the hydrological cycle in which changes in rainfall interception contribute significantly to the observed differences. However, little is known about the effects of more gradual changes in forest structure and at regional scales. We studied land use types ranging from natural forest over selectively-logged forest to cacao agroforest in a lower montane region in Central Sulawesi, Indonesia, and tested the suitability of high-resolution optical satellite imagery for modeling observed interception patterns. Investigated characteristics indicating canopy structure were mean and standard deviation of reflectance values, local maxima, and self-similarity measures based on the grey level co-occurrence matrix and geostatistical variogram analysis. Previously studied and published rainfall interception data comprised twelve plots and median values per land use type ranged from 30% in natural forest to 18% in cacao agroforests. A linear regression model with local maxima, mean contrast and normalized digital vegetation index (NDVI) as regressors was able to explain more than 84% ( Radj2) of the variation encountered in the data. Other investigated characteristics did not prove significant in the regression analysis. The model yielded stable results with respect to cross-validation and also produced realistic values and spatial patterns when applied at the landscape level (783.6 ha). High values of interception were rare and localized in natural forest stands distant to villages, whereas low interception characterized the intensively used sites close to settlements. We conclude that forest use intensity significantly reduced rainfall interception and satellite image analysis can successfully be applied for its regional prediction, and most forest in the study region has already been subject to human-induced structural changes.

A parameter estimation algorithm for LFM/BPSK hybrid modulated signal intercepted by Nyquist folding receiver

NASA Astrophysics Data System (ADS)

Qiu, Zhaoyang; Wang, Pei; Zhu, Jun; Tang, Bin

2016-12-01

Nyquist folding receiver (NYFR) is a novel ultra-wideband receiver architecture which can realize wideband receiving with a small amount of equipment. Linear frequency modulated/binary phase shift keying (LFM/BPSK) hybrid modulated signal is a novel kind of low probability interception signal with wide bandwidth. The NYFR is an effective architecture to intercept the LFM/BPSK signal and the LFM/BPSK signal intercepted by the NYFR will add the local oscillator modulation. A parameter estimation algorithm for the NYFR output signal is proposed. According to the NYFR prior information, the chirp singular value ratio spectrum is proposed to estimate the chirp rate. Then, based on the output self-characteristic, matching component function is designed to estimate Nyquist zone (NZ) index. Finally, matching code and subspace method are employed to estimate the phase change points and code length. Compared with the existing methods, the proposed algorithm has a better performance. It also has no need to construct a multi-channel structure, which means the computational complexity for the NZ index estimation is small. The simulation results demonstrate the efficacy of the proposed algorithm.

Actively driven thermal radiation shield

DOEpatents

Madden, Norman W.; Cork, Christopher P.; Becker, John A.; Knapp, David A.

2002-01-01

A thermal radiation shield for cooled portable gamma-ray spectrometers. The thermal radiation shield is located intermediate the vacuum enclosure and detector enclosure, is actively driven, and is useful in reducing the heat load to mechanical cooler and additionally extends the lifetime of the mechanical cooler. The thermal shield is electrically-powered and is particularly useful for portable solid-state gamma-ray detectors or spectrometers that dramatically reduces the cooling power requirements. For example, the operating shield at 260K (40K below room temperature) will decrease the thermal radiation load to the detector by 50%, which makes possible portable battery operation for a mechanically cooled Ge spectrometer.

Real-World Contexts, Multiple Representations, Student-Invented Terminology, and Y-Intercept

ERIC Educational Resources Information Center

Davis, Jon D.

2007-01-01

One classroom using two units from a "Standards"-based curriculum was the focus of a study designed to examine the effects of real-world contexts, delays in the introduction of formal mathematics terminology, and multiple function representations on student understanding. Students developed their own terminology for y-intercept, which was tightly…

Gross rainfall amount and maximum rainfall intensity in 60-minute influence on interception loss of shrubs: a 10-year observation in the Tengger Desert

PubMed Central

Zhang, Zhi-Shan; Zhao, Yang; Li, Xin-Rong; Huang, Lei; Tan, Hui-Juan

2016-01-01

In water-limited regions, rainfall interception is influenced by rainfall properties and crown characteristics. Rainfall properties, aside from gross rainfall amount and duration (GR and RD), maximum rainfall intensity and rainless gap (RG), within rain events may heavily affect throughfall and interception by plants. From 2004 to 2014 (except for 2007), individual shrubs of Caragana korshinskii and Artemisia ordosica were selected to measure throughfall during 210 rain events. Various rainfall properties were auto-measured and crown characteristics, i.e., height, branch and leaf area index, crown area and volume of two shrubs were also measured. The relative interceptions of C. korshinskii and A. ordosica were 29.1% and 17.1%, respectively. Rainfall properties have more contributions than crown characteristics to throughfall and interception of shrubs. Throughfall and interception of shrubs can be explained by GR, RI60 (maximum rainfall intensities during 60 min), RD and RG in deceasing importance. However, relative throughfall and interception of two shrubs have different responses to rainfall properties and crown characteristics, those of C. korshinskii were closely related to rainfall properties, while those of A. ordosica were more dependent on crown characteristics. We highlight long-term monitoring is very necessary to determine the relationships between throughfall and interception with crown characteristics. PMID:27184918

Gross rainfall amount and maximum rainfall intensity in 60-minute influence on interception loss of shrubs: a 10-year observation in the Tengger Desert.

PubMed

Zhang, Zhi-Shan; Zhao, Yang; Li, Xin-Rong; Huang, Lei; Tan, Hui-Juan

2016-05-17

In water-limited regions, rainfall interception is influenced by rainfall properties and crown characteristics. Rainfall properties, aside from gross rainfall amount and duration (GR and RD), maximum rainfall intensity and rainless gap (RG), within rain events may heavily affect throughfall and interception by plants. From 2004 to 2014 (except for 2007), individual shrubs of Caragana korshinskii and Artemisia ordosica were selected to measure throughfall during 210 rain events. Various rainfall properties were auto-measured and crown characteristics, i.e., height, branch and leaf area index, crown area and volume of two shrubs were also measured. The relative interceptions of C. korshinskii and A. ordosica were 29.1% and 17.1%, respectively. Rainfall properties have more contributions than crown characteristics to throughfall and interception of shrubs. Throughfall and interception of shrubs can be explained by GR, RI60 (maximum rainfall intensities during 60 min), RD and RG in deceasing importance. However, relative throughfall and interception of two shrubs have different responses to rainfall properties and crown characteristics, those of C. korshinskii were closely related to rainfall properties, while those of A. ordosica were more dependent on crown characteristics. We highlight long-term monitoring is very necessary to determine the relationships between throughfall and interception with crown characteristics.

Prediction models for clustered data: comparison of a random intercept and standard regression model.

PubMed

Bouwmeester, Walter; Twisk, Jos W R; Kappen, Teus H; van Klei, Wilton A; Moons, Karel G M; Vergouwe, Yvonne

2013-02-15

When study data are clustered, standard regression analysis is considered inappropriate and analytical techniques for clustered data need to be used. For prediction research in which the interest of predictor effects is on the patient level, random effect regression models are probably preferred over standard regression analysis. It is well known that the random effect parameter estimates and the standard logistic regression parameter estimates are different. Here, we compared random effect and standard logistic regression models for their ability to provide accurate predictions. Using an empirical study on 1642 surgical patients at risk of postoperative nausea and vomiting, who were treated by one of 19 anesthesiologists (clusters), we developed prognostic models either with standard or random intercept logistic regression. External validity of these models was assessed in new patients from other anesthesiologists. We supported our results with simulation studies using intra-class correlation coefficients (ICC) of 5%, 15%, or 30%. Standard performance measures and measures adapted for the clustered data structure were estimated. The model developed with random effect analysis showed better discrimination than the standard approach, if the cluster effects were used for risk prediction (standard c-index of 0.69 versus 0.66). In the external validation set, both models showed similar discrimination (standard c-index 0.68 versus 0.67). The simulation study confirmed these results. For datasets with a high ICC (≥15%), model calibration was only adequate in external subjects, if the used performance measure assumed the same data structure as the model development method: standard calibration measures showed good calibration for the standard developed model, calibration measures adapting the clustered data structure showed good calibration for the prediction model with random intercept. The models with random intercept discriminate better than the standard model only

Frequency-independent radiation modes of interior sound radiation: Experimental study and global active control

NASA Astrophysics Data System (ADS)

Hesse, C.; Papantoni, V.; Algermissen, S.; Monner, H. P.

2017-08-01

Active control of structural sound radiation is a promising technique to overcome the poor passive acoustic isolation performance of lightweight structures in the low-frequency region. Active structural acoustic control commonly aims at the suppression of the far-field radiated sound power. This paper is concerned with the active control of sound radiation into acoustic enclosures. Experimental results of a coupled rectangular plate-fluid system under stochastic excitation are presented. The amplitudes of the frequency-independent interior radiation modes are determined in real-time using a set of structural vibration sensors, for the purpose of estimating their contribution to the acoustic potential energy in the enclosure. This approach is validated by acoustic measurements inside the cavity. Utilizing a feedback control approach, a broadband reduction of the global acoustic response inside the enclosure is achieved.

The Neuronal Control of Flying Prey Interception in Dragonflies

DTIC Science & Technology

2014-08-19

Gonzalez-Bellido’s fluorescent dye ( Lucifer -yellow) injections illuminated for the first time the anatomy of the output regions of the TSDNs...out in Cape Cod (MA) to test the effect of bead size(C), and in the Olberg Laboratory (Union College, NY) to test the effect of bead speed by...AFRL-OSR-VA-TR-2014-0193 THE NEURONAL CONTROL OF FLYING PREY INTERCEPTION IN DRAGONFLIES Robert Olberg TRUSTEES OF UNION COLLEGE IN THE TOWN OF

Is perception of self-motion speed a necessary condition for intercepting a moving target while walking?

PubMed

Morice, Antoine H P; Wallet, Grégory; Montagne, Gilles

2014-04-30

While it has been shown that the Global Optic Flow Rate (GOFR) is used in the control of self-motion speed, this study examined its relevance in the control of interceptive actions while walking. We asked participants to intercept approaching targets by adjusting their walking speed in a virtual environment, and predicted that the influence of the GOFR depended on their interception strategy. Indeed, unlike the Constant Bearing Angle (CBA), the Modified Required Velocity (MRV) strategy relies on the perception of self-displacement speed. On the other hand, the CBA strategy involves specific speed adjustments depending on the curvature of the target's trajectory, whereas the MRV does not. We hypothesized that one strategy is selected among the two depending on the informational content of the environment. We thus manipulated the curvature and display of the target's trajectory, and the relationship between physical walking speed and the GOFR (through eye height manipulations). Our results showed that when the target trajectory was not displayed, walking speed profiles were affected by curvature manipulations. Otherwise, walking speed profiles were less affected by curvature manipulations and were affected by the GOFR manipulations. Taken together, these results show that the use of the GOFR for intercepting a moving target while walking depends on the informational content of the environment. Finally we discuss the complementary roles of these two perceptual-motor strategies. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Predictive saccade in the absence of smooth pursuit: interception of moving targets in the archer fish.

PubMed

Ben-Simon, Avi; Ben-Shahar, Ohad; Vasserman, Genadiy; Segev, Ronen

2012-12-15

Interception of fast-moving targets is a demanding task many animals solve. To handle it successfully, mammals employ both saccadic and smooth pursuit eye movements in order to confine the target to their area centralis. But how can non-mammalian vertebrates, which lack smooth pursuit, intercept moving targets? We studied this question by exploring eye movement strategies employed by archer fish, an animal that possesses an area centralis, lacks smooth pursuit eye movements, but can intercept moving targets by shooting jets of water at them. We tracked the gaze direction of fish during interception of moving targets and found that they employ saccadic eye movements based on prediction of target position when it is hit. The fish fixates on the target's initial position for ∼0.2 s from the onset of its motion, a time period used to predict whether a shot can be made before the projection of the target exits the area centralis. If the prediction indicates otherwise, the fish performs a saccade that overshoots the center of gaze beyond the present target projection on the retina, such that after the saccade the moving target remains inside the area centralis long enough to prepare and perform a shot. These results add to the growing body of knowledge on biological target tracking and may shed light on the mechanism underlying this behavior in other animals with no neural system for the generation of smooth pursuit eye movements.

Activating PTEN by COX-2 inhibitors antagonizes radiation-induced AKT activation contributing to radiosensitization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meng, Zhen; Department of Oral & Maxillofacial Surgery, Peking University School and Hospital of Stomatology, 22 Zhongguancun Avenue South, Haidian District, Beijing 100081; Gan, Ye-Hua, E-mail: kqyehuagan@bjmu.edu.cn

2015-05-01

Radiotherapy is still one of the most effective nonsurgical treatments for many tumors. However, radioresistance remains a major impediment to radiotherapy. Although COX-2 inhibitors can induce radiosensitization, the underlying mechanism is not fully understood. In this study, we showed that COX-2 selective inhibitor celecoxib enhanced the radiation-induced inhibition of cell proliferation and apoptosis in HeLa and SACC-83 cells. Treatment with celecoxib alone dephosphorylated phosphatase and tensin homolog deleted on chromosome ten (PTEN), promoted PTEN membrane translocation or activation, and correspondingly dephosphorylated or inactivated protein kinase B (AKT). By contrast, treatment with radiation alone increased PTEN phosphorylation, inhibited PTEN membrane translocationmore » and correspondingly activated AKT in the two cell lines. However, treatment with celecoxib or another COX-2 selective inhibitor (valdecoxib) completely blocked radiation-induced increase of PTEN phosphorylation, rescued radiation-induced decrease in PTEN membrane translocation, and correspondingly inactivated AKT. Moreover, celecoxib could also upregulate PTEN protein expression by downregulating Sp1 expression, thereby leading to the activation of PTEN transcription. Our results suggested that COX-2 inhibitors could enhance radiosensitization at least partially by activating PTEN to antagonize radiation-induced AKT activation. - Highlights: • COX-2 inhibitor, celecoxib, could enhance radiosensitization. • Radiation induced PTEN inactivation (phosphorylation) and AKT activation. • COX-2 inhibitor induced PTEN expression and activation, and inactivated AKT. • COX-2 inhibitor enhanced radiosensitization through activating PTEN.« less

The densiometer for measurement of crown intercept above a line transect.

Treesearch

J. Edward Dealy

1960-01-01

An adaptation in the use of Lemmon's spherical densiometer, has been developed to measure low overstory crown foliage as intercept above a line transect. This adaptation provides added information for the evaluation of ecological relationships within and among plant communities where some species are too low for overstory density estimates and too high for direct...

Modelling rainfall interception by forests: a new method for estimating the canopy storage capacity

NASA Astrophysics Data System (ADS)

Pereira, Fernando; Valente, Fernanda; Nóbrega, Cristina

2015-04-01

Evaporation of rainfall intercepted by forests is usually an important part of a catchment water balance. Recognizing the importance of interception loss, several models of the process have been developed. A key parameter of these models is the canopy storage capacity (S), commonly estimated by the so-called Leyton method. However, this method is somewhat subjective in the selection of the storms used to derive S, which is particularly critical when throughfall is highly variable in space. To overcome these problems, a new method for estimating S was proposed in 2009 by Pereira et al. (Agricultural and Forest Meteorology, 149: 680-688), which uses information from a larger number of storms, is less sensitive to throughfall spatial variability and is consistent with the formulation of the two most widely used rainfall interception models, Gash analytical model and Rutter model. However, this method has a drawback: it does not account for stemflow (Sf). To allow a wider use of this methodology, we propose now a revised version which makes the estimation of S independent of the importance of stemflow. For the application of this new version we only need to establish a linear regression of throughfall vs. gross rainfall using data from all storms large enough to saturate the canopy. Two of the parameters used by the Gash and the Rutter models, pd (the drainage partitioning coefficient) and S, are then derived from the regression coefficients: pd is firstly estimated allowing then the derivation of S but, if Sf is not considered, S can be estimated making pd= 0. This new method was tested using data from a eucalyptus plantation, a maritime pine forest and a traditional olive grove, all located in Central Portugal. For both the eucalyptus and the pine forests pd and S estimated by this new approach were comparable to the values derived in previous studies using the standard procedures. In the case of the traditional olive grove, the estimates obtained by this methodology

Measurement of snow interception and canopy effects on snow accumulation and melt in a mountainous maritime climate, Oregon, United States

NASA Astrophysics Data System (ADS)

Storck, Pascal; Lettenmaier, Dennis P.; Bolton, Susan M.

2002-11-01

The results of a 3 year field study to observe the processes controlling snow interception by forest canopies and under canopy snow accumulation and ablation in mountain maritime climates are reported. The field study was further intended to provide data to develop and test models of forest canopy effects on beneath-canopy snowpack accumulation and melt and the plot and stand scales. Weighing lysimeters, cut-tree experiments, and manual snow surveys were deployed at a site in the Umpqua National Forest, Oregon (elevation 1200 m). A unique design for a weighing lysimeter was employed that allowed continuous measurements of snowpack evolution beneath a forest canopy to be taken at a scale unaffected by variability in canopy throughfall. Continuous observations of snowpack evolution in large clearings were made coincidentally with the canopy measurements. Large differences in snow accumulation and ablation were observed at sites beneath the forest canopy and in large clearings. These differences were not well described by simple relationships between the sites. Over the study period, approximately 60% of snowfall was intercepted by the canopy (up to a maximum of about 40 mm water equivalent). Instantaneous sublimation rates exceeded 0.5 mm per hour for short periods. However, apparent average sublimation from the intercepted snow was less than 1 mm per day and totaled approximately 100 mm per winter season. Approximately 72 and 28% of the remaining intercepted snow was removed as meltwater drip and large snow masses, respectively. Observed differences in snow interception rate and maximum snow interception capacity between Douglas fir (Pseudotsuga menziesii), white fir (Abies concolor), ponderosa pine (Pinus ponderosa), and lodgepole pine (Pinus contorta) were minimal.

Implication of Intrastorm Rainfall-Canopy Interaction on Interception Performance of Broadleaf Evergreen Shrubs in Urban Setting

NASA Astrophysics Data System (ADS)

Yerk, W.; Montalto, F. A.

2014-12-01

Because of its ability to intercept a portion of rainfall, vegetated canopy has a significant influence on the urban hydrological cycle. In turn, urban watersheds, characterized by large impervious areas, have an enormous and often adverse impact on receiving waters. However, most historical interception research has been dedicated to forest canopies. The goal of our research was to quantify rainfall partitioning by isolated evergreen canopies in an urban setting. Two years of the field experiment involved three exemplars of Cherry Laurel (Prunus laurocerasus'Otto Luyken'.) Each plant had ten rain gauges to measure throughfall with a five second sampling frequency. A number of preventive techniques were introduced to minimize the gauges' errors (e.g., splash-in, splash-out and excessive wetting.) Leaf area index was measured manually. We estimated the canopy storage capacity to be less than 0.5 mm. An on-site automated weather station provided meteorological data. Cumulative interception loss for the periods of August-December 2013 and April-July 2014 was 51%. Phenological change did not show a stable pattern of influence on throughfall depths. Measurements in May and July 2014 showed a high variability of stemflow (2-16%) between rain events. Throughfall and precipitation intensities (mm/hr) expressed strong linear relationships (adjusted coefficient of determination R20.79) for the entire range of observed rainfall intensities. The ratio of throughfall to precipitation intensity was 0.49:1. The observations suggest that reduction of throughfall intensity by the canopy during a rainstorm determines the bulk of interception depth. In contrast, the amount of water stored on the canopy and evaporated between and after rain events contributes minimally to interception. Simulations of potential evaporation based on the Penman-Monteith method revealed a serious underestimation of evaporation from the wet canopy surfaces during the rain events. Mechanisms other than heat

Functional Design for Air Intercept Controller Prototype Training System.

DTIC Science & Technology

1981-12-01

DEC 81 E REGELSON. 0 SLENON, R VERSTEE6 N61339-?-C-OIG* UNCLASSIFIED G61I-A009 NAVTRAEUIPC-70-C-0182-B 14. . !EEEEEEEEEEElIEEIIIEEIIEEI IEIIEIIIEIIII...INTERCEPT CON4TROLLER PROTOTYPE TRAINING SYSTEK E . Regelson, G. Slemon, R. VerSteeg, R. Halley Logicon, Inc. Tactical & Training Systems Division Post...Final epr 7. AUTWOaN( L CONTRACT OR GONI’?MUMBILN(s) E . Regelson, G. Slemon, R. VerSteeg, R. Halley N61339-78-C-0182 9. P6141ORMING ORGANIZATION

A study on crown interception with four dominant tree species: a direct measurement

Treesearch

Xiang Li; Jianzhi Niu; Linus Zhang; Qingfu Xiao; Gregory E. McPherson; Natalie van Doorn; Xinxiao Yu; Baoyuan Xie; Salli Dymond; Jiao Li; Chen Meng; Ziteng Luo

2016-01-01

An experiment was conducted to concentrate on the rainfall interception process of individual trees for four common species in Beijing, China, which included needle species (Platycladus orientalis and Pinus tabulaeformis) and broadleaf species (Quercus variabilis and Acer truncatum)....

Space activities and radiation protection of crew members

NASA Astrophysics Data System (ADS)

Straube, Ulrich; Berger, Thomas; Reitz, Guenther; Facius, Rainer; Reiter, Thomas; Kehl, Marcel; Damann, M. D. Volker; Tognini, Michel

Personnel working as crew in space-based activities e.g. professional astronauts and cosmo-nauts but also -to a certain extend-space flight participants ("space tourists"), demand health and safety considerations that have to include radiation protection measures. The radiation environment that a crew is exposed to during a space flight, differs significantly to that found on earth including commercial aviation, mainly due to the presence of heavy charged particles with great potential for biological damage. The exposure exceeds those routinely received by terrestrial radiation workers. A sequence of activities has to be conducted targeting to mitigate adverse effects of space radiation. Considerable information is available and applied through the joint efforts of the Space Agencies that are involved in the operations of the International Space Station, ISS. This presentation will give an introduction to the current measures for ra-diation monitoring and protection of astronauts of the European Space Agency (ESA). It will include information: on the radiation protection guidelines that shall ensure the proper imple-mentation and execution of radiation protection measures, the operational hardware used for radiation monitoring and personal dosimetry on ISS, as well as information about operational procedures that are applied.

Effects of Microwave Radiation on Neuronal Activity

DTIC Science & Technology

1991-10-01

salivary glands and human cultured cells to extremely low- frequency (ELF) EMF alters patterns of polypeptide synthesis (18,19). The effects displayed...at 16 Hz. Continuous exposure to radio- frequency radiation for 4 consecutive days led to the development of a cell number density gradient. The...RADIATION ON NEURONAL ACTIVITY SUMMARY The effects of radiofrequency radiation on rat hippocampal fetal neurons were examined. Carrier frequencies of 300 to

Motion patterns and phase-transition of a defender-intruder problem and optimal interception strategy of the defender

NASA Astrophysics Data System (ADS)

Wang, Jiangliu; Li, Wei

2015-10-01

In this paper, we consider a defense-intrusion interaction, in which an intruder is attracted by a protected stationary target but repulsed by a defender; while the defender tries to move towards an appropriate interception position (IP) between the intruder and the target in order to intercept the intruder and expel the intruder away from the target as maximum as possible. Intuitionally, to keep the intruder further away, one may wonder that: is it a better strategy for the defender trying to approach the intruder as near as possible? Unexpectedly and interestingly enough, this is not always the case. We first introduce the flexibility for IP selection, then investigate the system dynamics and the stable motion patterns, and characterize the phase-transition surface for the motion patterns. We show that, the phase-transition surface just defines the optimal interception strategy of the defender for IP selection; and from the perspective of mobility of agents, the optimal strategy just depends on relative mobility of the two agents.

Canopy Light Interception of a Conventional and an Erect Leaf Mutant Sorghum

USDA-ARS?s Scientific Manuscript database

Two sorghum lines, an erect leafed mutant sorghum and the wild type from which the mutant was generated, were field grown in rectilinear arrays at low (23 plants per square meter) and high (10 plants per square meter) population densities. Canopy light interception, biomass accretion and yield were ...

Genomic-Enabled Prediction Kernel Models with Random Intercepts for Multi-environment Trials

PubMed Central

Cuevas, Jaime; Granato, Italo; Fritsche-Neto, Roberto; Montesinos-Lopez, Osval A.; Burgueño, Juan; Bandeira e Sousa, Massaine; Crossa, José

2018-01-01

In this study, we compared the prediction accuracy of the main genotypic effect model (MM) without G×E interactions, the multi-environment single variance G×E deviation model (MDs), and the multi-environment environment-specific variance G×E deviation model (MDe) where the random genetic effects of the lines are modeled with the markers (or pedigree). With the objective of further modeling the genetic residual of the lines, we incorporated the random intercepts of the lines (l) and generated another three models. Each of these 6 models were fitted with a linear kernel method (Genomic Best Linear Unbiased Predictor, GB) and a Gaussian Kernel (GK) method. We compared these 12 model-method combinations with another two multi-environment G×E interactions models with unstructured variance-covariances (MUC) using GB and GK kernels (4 model-method). Thus, we compared the genomic-enabled prediction accuracy of a total of 16 model-method combinations on two maize data sets with positive phenotypic correlations among environments, and on two wheat data sets with complex G×E that includes some negative and close to zero phenotypic correlations among environments. The two models (MDs and MDE with the random intercept of the lines and the GK method) were computationally efficient and gave high prediction accuracy in the two maize data sets. Regarding the more complex G×E wheat data sets, the prediction accuracy of the model-method combination with G×E, MDs and MDe, including the random intercepts of the lines with GK method had important savings in computing time as compared with the G×E interaction multi-environment models with unstructured variance-covariances but with lower genomic prediction accuracy. PMID:29476023

Absorber for terahertz radiation management

DOEpatents

Biallas, George Herman; Apeldoorn, Cornelis; Williams, Gwyn P.; Benson, Stephen V.; Shinn, Michelle D.; Heckman, John D.

2015-12-08

A method and apparatus for minimizing the degradation of power in a free electron laser (FEL) generating terahertz (THz) radiation. The method includes inserting an absorber ring in the FEL beam path for absorbing any irregular THz radiation and thus minimizes the degradation of downstream optics and the resulting degradation of the FEL output power. The absorber ring includes an upstream side, a downstream side, and a plurality of wedges spaced radially around the absorber ring. The wedges form a scallop-like feature on the innermost edges of the absorber ring that acts as an apodizer, stopping diffractive focusing of the THz radiation that is not intercepted by the absorber. Spacing between the scallop-like features and the shape of the features approximates the Bartlett apodization function. The absorber ring provides a smooth intensity distribution, rather than one that is peaked on-center, thereby eliminating minor distortion downstream of the absorber.

Anticipating the effects of gravity when intercepting moving objects: differentiating up and down based on nonvisual cues.

PubMed

Senot, Patrice; Zago, Myrka; Lacquaniti, Francesco; McIntyre, Joseph

2005-12-01

Intercepting an object requires a precise estimate of its time of arrival at the interception point (time to contact or "TTC"). It has been proposed that knowledge about gravitational acceleration can be combined with first-order, visual-field information to provide a better estimate of TTC when catching falling objects. In this experiment, we investigated the relative role of visual and nonvisual information on motor-response timing in an interceptive task. Subjects were immersed in a stereoscopic virtual environment and asked to intercept with a virtual racket a ball falling from above or rising from below. The ball moved with different initial velocities and could accelerate, decelerate, or move at a constant speed. Depending on the direction of motion, the acceleration or deceleration of the ball could therefore be congruent or not with the acceleration that would be expected due to the force of gravity acting on the ball. Although the best success rate was observed for balls moving at a constant velocity, we systematically found a cross-effect of ball direction and acceleration on success rate and response timing. Racket motion was triggered on average 25 ms earlier when the ball fell from above than when it rose from below, whatever the ball's true acceleration. As visual-flow information was the same in both cases, this shift indicates an influence of the ball's direction relative to gravity on response timing, consistent with the anticipation of the effects of gravity on the flight of the ball.

Prediction models for clustered data: comparison of a random intercept and standard regression model

PubMed Central

2013-01-01

Background When study data are clustered, standard regression analysis is considered inappropriate and analytical techniques for clustered data need to be used. For prediction research in which the interest of predictor effects is on the patient level, random effect regression models are probably preferred over standard regression analysis. It is well known that the random effect parameter estimates and the standard logistic regression parameter estimates are different. Here, we compared random effect and standard logistic regression models for their ability to provide accurate predictions. Methods Using an empirical study on 1642 surgical patients at risk of postoperative nausea and vomiting, who were treated by one of 19 anesthesiologists (clusters), we developed prognostic models either with standard or random intercept logistic regression. External validity of these models was assessed in new patients from other anesthesiologists. We supported our results with simulation studies using intra-class correlation coefficients (ICC) of 5%, 15%, or 30%. Standard performance measures and measures adapted for the clustered data structure were estimated. Results The model developed with random effect analysis showed better discrimination than the standard approach, if the cluster effects were used for risk prediction (standard c-index of 0.69 versus 0.66). In the external validation set, both models showed similar discrimination (standard c-index 0.68 versus 0.67). The simulation study confirmed these results. For datasets with a high ICC (≥15%), model calibration was only adequate in external subjects, if the used performance measure assumed the same data structure as the model development method: standard calibration measures showed good calibration for the standard developed model, calibration measures adapting the clustered data structure showed good calibration for the prediction model with random intercept. Conclusion The models with random intercept discriminate

Active personal radiation monitor for lunar EVA

NASA Astrophysics Data System (ADS)

Straume, Tore; Borak, Tom; Braby, L. A.; Lusby, Terry; Semones, Edward J.; Vazquez, Marcelo E.

As astronauts return to the Moon-and this time, work for extended periods-there will be a critical need for crew personnel radiation monitoring as they operate lunar rovers or otherwise perform a myriad of extravehicular activities (EVAs). Our focus is on development of a small personal radiation monitor for lunar EVA that responds to the complex radiation quality and changing dose rates on the Moon. Of particular concern are active monitoring capabilities that provide both early warning and radiation dosimetry information during solar particle events (SPEs). To accomplish this, we are developing small detectors integrated with modern high speed, low power microelectronics to measure dose-rate and dose-mean lineal energy in real time. The monitor is designed to perform over the range of dose rates and LETs expected from both GCR and SPE radiations during lunar EVA missions. The monitor design provides simultaneous measurement of dose-equivalent rates at two tissue-equivalent depths simulating skin and marrow. The compact personal monitor is estimated to be the size of a cell phone and would fit on an EVA spacesuit (e.g., in backpack) or in a toolbox. The four-year development effort (which began December 2007) will result in a prototype radiation monitor field tested and characterized for the major radiations expected on the surface of the Moon. We acknowledge support from NSBRI through grants to NASA Ames Research Center (T. Straume, PI) and Colorado State University (T. Borak, PI).

Compound simulator IR radiation characteristics test and calibration

NASA Astrophysics Data System (ADS)

Li, Yanhong; Zhang, Li; Li, Fan; Tian, Yi; Yang, Yang; Li, Zhuo; Shi, Rui

2015-10-01

The Hardware-in-the-loop simulation can establish the target/interference physical radiation and interception of product flight process in the testing room. In particular, the simulation of environment is more difficult for high radiation energy and complicated interference model. Here the development in IR scene generation produced by a fiber array imaging transducer with circumferential lamp spot sources is introduced. The IR simulation capability includes effective simulation of aircraft signatures and point-source IR countermeasures. Two point-sources as interference can move in two-dimension random directions. For simulation the process of interference release, the radiation and motion characteristic is tested. Through the zero calibration for optical axis of simulator, the radiation can be well projected to the product detector. The test and calibration results show the new type compound simulator can be used in the hardware-in-the-loop simulation trial.

Evaluating interception of larval pallid sturgeon on the Lower Missouri River- data acquisition, interpolation, and visualization

NASA Astrophysics Data System (ADS)

Bulliner, E. A., IV; Erwin, S. O.; Anderson, B. J.; Wilson, H.; Jacobson, R. B.

2016-12-01

The transition from endogenous to exogenous feeding is an important life-stage transition for many riverine fish larvae. On the Missouri River, U.S., riverine alteration has decreased connectivity between the navigation channel and complex, food-producing and foraging areas on the channel margins, namely shallow side channels and sandbar complexes. A favored hypothesis, the interception hypothesis, for recruitment failure of pallid sturgeon is that drifting larvae are not able to exit the highly engineered navigation channel, and therefore starve. We present work exploring measures of hydraulic connectivity between the navigation channel and channel margins using multiple data-collection protocols with acoustic Doppler current profilers (ADCPs). As ADCP datasets alone often do not have high enough spatial resolution to characterize interception and connectivity sufficiently at the scale of drifting sturgeon larvae, they are often supplemented with physical and empirical models. Using boat-mounted ADCPs, we collected 3-dimensional current velocities with a variety of driving techniques (specifically, regularly spaced transects, reciprocal transects, and irregular patterns) around areas of potential larval interception. We then used toolkits based in Python to interpolate 3-dimensional velocity fields at spatial scales finer than the original measurements, and visualized resultant velocity vectors and flowlines in the software package Paraview. Using these visualizations, we investigated the necessary resolution of field measurements required to model connectivity with channel margin areas on large, highly engineered river ecosystems such as the Missouri River. We anticipate that results from this work will be used to help inform models of larval interception under current conditions. Furthermore, results from this work will be useful in developing monitoring strategies to evaluate the restoration of channel complexity to support ecological functions.

[Characteristics of rainfall interception by Caragana korshinskii and Hippophae rhamnoides in Loess Plateau of Northwest China].

PubMed

Jian, Sheng-Qi; Zhao, Chuan-Yan; Fang, Shu-Min; Yu, Kai; Wang, Yang; Liu, Yi-Yue; Zheng, Xiang-Lin; Peng, Shou-Zhang

2012-09-01

From May to October 2011, an investigation was conducted on the effects of rainfall and its intensity on the canopy interception, throughfall, and stemflow of Caragana korshinskii and Hippophae rhamnoides, the main shrub species commonly planted to stabilize soil and water in the Anjiagou catchment of Loess Plateau. A total of 47 rainfall events were observed, most of which were featured with low intensity, and the total amount and average intensity of the rainfalls were 208.9 mm and 2.82 mm x h(-1), respectively. As a whole, the rainfall events of 2-10 mm and 0.1-2 mm x h(-1) had the highest frequency. The canopy interception, throughfall, and stemflow of C. korshinski were 58.5 mm (28%), 124.7 mm (59.7%), and 25.7 mm (12.3%), while those of H. rhamnoides were 17.6 mm (8.4%), 153. 1 mm (73.3%), and 38.2 mm (18.3%), respectively. Regression analysis showed that the canopy interception, throughfall, and stemflow of the two shrub species all had significant positive correlations with the rainfall amount, and had exponent or power correlations with the rainfall amount and the maximum rainfall intensity in 10 minutes.

Genomic-Enabled Prediction Kernel Models with Random Intercepts for Multi-environment Trials.

PubMed

Cuevas, Jaime; Granato, Italo; Fritsche-Neto, Roberto; Montesinos-Lopez, Osval A; Burgueño, Juan; Bandeira E Sousa, Massaine; Crossa, José

2018-03-28

In this study, we compared the prediction accuracy of the main genotypic effect model (MM) without G×E interactions, the multi-environment single variance G×E deviation model (MDs), and the multi-environment environment-specific variance G×E deviation model (MDe) where the random genetic effects of the lines are modeled with the markers (or pedigree). With the objective of further modeling the genetic residual of the lines, we incorporated the random intercepts of the lines ([Formula: see text]) and generated another three models. Each of these 6 models were fitted with a linear kernel method (Genomic Best Linear Unbiased Predictor, GB) and a Gaussian Kernel (GK) method. We compared these 12 model-method combinations with another two multi-environment G×E interactions models with unstructured variance-covariances (MUC) using GB and GK kernels (4 model-method). Thus, we compared the genomic-enabled prediction accuracy of a total of 16 model-method combinations on two maize data sets with positive phenotypic correlations among environments, and on two wheat data sets with complex G×E that includes some negative and close to zero phenotypic correlations among environments. The two models (MDs and MDE with the random intercept of the lines and the GK method) were computationally efficient and gave high prediction accuracy in the two maize data sets. Regarding the more complex G×E wheat data sets, the prediction accuracy of the model-method combination with G×E, MDs and MDe, including the random intercepts of the lines with GK method had important savings in computing time as compared with the G×E interaction multi-environment models with unstructured variance-covariances but with lower genomic prediction accuracy. Copyright © 2018 Cuevas et al.

The Amazon forest-rainfall feedback: the roles of transpiration and interception

NASA Astrophysics Data System (ADS)

Dekker, Stefan; Staal, Arie; Tuinenburg, Obbe

2017-04-01

In the Amazon, deep-rooted trees increase local transpiration and high tree cover increase local interception evaporation. These increased local evapotranspiration fluxes to the atmosphere have both positive effects on forests down-wind, as they stimulate rainfall. Although important for the functioning of the Amazon, we have an inadequate assessment on the strength and the timing of these forest-rainfall feedbacks. In this study we (i) estimate local forest transpiration and local interception evaporation, (ii) simulate the trajectories of these moisture flows through the atmosphere and (iii) quantify their contributions to the forest-rainfall feedback for the whole Amazon basin. To determine the atmospheric moisture flows in tropical South America we use a Lagrangian moisture tracking algorithm on 0.25° (c. 25 km) resolution with eight atmospheric layers on a monthly basis for the period 2003-2015. With our approach we account for multiple re-evaporation cycles of this moisture. We also calculate for each month the potential effects of forest loss on evapotranspiration. Combined, these calculations allow us to simulate the effects of land-cover changes on rainfall in downwind areas and estimate the effect on the forest. We found large regional and temporal differences in the importance how forest contribute to rainfall. The transpiration-rainfall feedback is highly important during the dry season. Between September-November, when large parts of the Amazon are at the end of the dry season, more than 50% of the rainfall is caused by the forests upstream. This means that droughts in the Amazon are alleviated by the forest. Furthermore, we found that much moisture cycles several times during its trajectory over the Amazon. After one evapotranspiration-rainfall cycle, more than 40% of the moisture is re-evaporated again. The interception-evaporation feedback is less important during droughts. Finally from our analysis, we show that the forest-rainfall feedback is

Comparing Food Label Experiments Using Samples from Web Panels versus Mall Intercepts

ERIC Educational Resources Information Center

Chang, LinChiat; Lin, Chung-Tung Jordan

2015-01-01

To regulate health messages on food labels, the U.S. Food and Drug Administration (FDA) traditionally relied on mall intercepts to collect consumer data. In recent years, web surveys have presented a viable alternative for presenting visual stimuli with more control and efficiency in data collection. However, there is a paucity of empirical data…

[Interception Effect of Ecological Ditch on Nitrogen Transport in Agricultural Runoff in Subtropical China].

PubMed

Wang, Di; Li, Hong-fang; Liu, Feng; Wang, Yi; Zhong, Yuan-chun; He, Yang; Xiao, Run-fin; Wu, Jin-shui

2016-05-15

Interception effects of an ecological ditch, used to control agricultural non-point source pollution in subtropical China, on nitrogen transport in surface runoff were studied by monthly measuring the runoff volume and concentrations of ammonium nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃⁻-N) and total nitrogen (TN) at the ditch inlet and outlet from 2013 to 2014. In addition, differences of NH₄⁺-N, NO₃⁻-N and TN removal were compared between 2013 and 2014. The results showed that the study ecological ditch worked effectively in N removal with average NH₄⁺-N, NO₃⁻-N and TN removal rates of 77.8%, 58.3%, and 48.7%; and their interception rates were 38.4, 59.6, and 171.1 kg · a⁻¹, respectively. The average proportion of NH₄⁺-N and NO₃⁻-N in TN was 47.5% at inlet, and 33.6% at outlet, which was significantly lower than that at inlet (P < 0.01). All hydrophytes in the ecological ditch were replaced by Myriophyllum aquaticum in 2014, which led to the increased average NO₃⁻-N and TN removal rates of 30.5% and 18.2%, respectively, Compared to in 2013. The vegetation of Myriophyllum aquaticum was beneficial to the improvement of N interception in ecological ditch. These findings clearly demonstrated that ecological ditch can substantially reduce N loss from surface runoff and be used as an important technique to prevent agricultural non-point N pollution.

An improved growth intercept method for estimating site index of red pine.

Treesearch

David H. Alban

1972-01-01

Equations for predicting red pine (Pinus resinosa Ait.) site index from various internode lengths were developed from ring counts on sectioned trees form 69 natural stands in Minnesota. The precision of estimating site index was much improved by measuring the 5-year growth intercept beginning at 7 feet above the ground rather than at the conventional breast height....

Intercept™ Panel Trap (INT PT) effective in management of forest Coleoptera

Treesearch

D. Czokajlo; J. McLaughlin; L. I. Abu Ayyash; S. Teale; J. Wickham; J. Warren; R. Hoffman; B. Aukema; K. Raffa; P. Kirsch

2003-01-01

Trap efficacy in capturing economically important forest Coleoptera was measured in field trials comparing the Intercept Panel Trap (INT PT) with the Multi-Funnel Trap. The INT PT was designed to provide a better option for the monitoring of forest Coleoptera. The trap is made of corrugated plastic and is very robust under rigorous field conditions, but still...

Active electromagnetic invisibility cloaking and radiation force cancellation

NASA Astrophysics Data System (ADS)

Mitri, F. G.

2018-03-01

This investigation shows that an active emitting electromagnetic (EM) Dirichlet source (i.e., with axial polarization of the electric field) in a homogeneous non-dissipative/non-absorptive medium placed near a perfectly conducting boundary can render total invisibility (i.e. zero extinction cross-section or efficiency) in addition to a radiation force cancellation on its surface. Based upon the Poynting theorem, the mathematical expression for the extinction, radiation and amplification cross-sections (or efficiencies) are derived using the partial-wave series expansion method in cylindrical coordinates. Moreover, the analysis is extended to compute the self-induced EM radiation force on the active source, resulting from the waves reflected by the boundary. The numerical results predict the generation of a zero extinction efficiency, achieving total invisibility, in addition to a radiation force cancellation which depend on the source size, the distance from the boundary and the associated EM mode order of the active source. Furthermore, an attractive EM pushing force on the active source directed toward the boundary or a repulsive pulling one pointing away from it can arise accordingly. The numerical predictions and computational results find potential applications in the design and development of EM cloaking devices, invisibility and stealth technologies.

A spacecraft attitude and articulation control system design for the Comet Halley intercept mission

NASA Technical Reports Server (NTRS)

Key, R. W.

1981-01-01

An attitude and articulation control system design for the Comet Halley 1986 intercept mission is presented. A spacecraft dynamics model consisting of five hinge-connected rigid bodies is used to analyze the spacecraft attitude and articulation control system performance. Inertial and optical information are combined to generate scan platform pointing commands. The comprehensive spacecraft model has been developed into a digital computer simulation program, which provides performance characteristics and insight pertaining to the control and dynamics of a Halley Intercept spacecraft. It is shown that scan platform pointing error has a maximum value of 1.8 milliradians during the four minute closest approach interval. It is also shown that the jitter or scan platform pointing rate error would have a maximum value of 2.5 milliradians/second for the nominal 1000 km closest approach distance trajectory and associated environment model.

Ni-Catalyzed Regioselective 1,2-Dicarbofunctionalization of Olefins by Intercepting Heck Intermediates as Imine-Stabilized Transient Metallacycles

DOE PAGES

Shrestha, Bijay; Basnet, Prakash; Dhungana, Roshan K.; ...

2017-07-24

We disclose a strategy for Ni-catalyzed regioselective dicarbofunctionalization of olefins in styrene derivatives by intercepting Heck C(sp 3)-NiX intermediates with arylzinc reagents. This approach utilizes a readily removable imine as a coordinating group that plays a dual role of intercepting oxidative addition species derived from aryl halides and triflates to promote Heck carbometallation, and stabilizing the Heck C(sp 3)-NiX intermediates as transient metallacycles to suppress β-hydride elimination and facilitate transmetalation/reductive elimination steps. This method affords diversely-substituted 1,1,2-riarylethyl products that occur as structural motifs in various natural products.

Assessing solar energy and water use efficiencies in winter wheat

NASA Technical Reports Server (NTRS)

Asrar, G.; Hipps, L. E.; Kanemasu, E. T.

1982-01-01

The water use and solar energy conversion efficiencies of two cultivars of winter wheat (Triticum aestivum L., vars, Centurk and Newton) planted at three densities, were examined during a growing season. Water use, based on soil moisture depletion, was the lowest under the light, and the highest under the heavy planting densities of both cultivars. Water use efficiency of medium and heavy planting densities were greater than the light planting densities in both cultivars. The canopy radiation extinction coefficients of both cultivars increased with increases in planting density. Efficiency of operation interception of photosynthetically active radiation by both cultivars improved from the time of jointing until anthesis, and then decreased during senescence. The efficiency of the conversion of intercepted radiation to dry matter (biochemical efficiency) decreased throughout the growing season both cultivars. The interception, biochemical, and photosynthetic efficiencies improved as planting density increased.

The canopy interception-landslide initiation conundrum: insight from a tropical secondary forest in northern Thailand

NASA Astrophysics Data System (ADS)

Sidle, Roy C.; Ziegler, Alan D.

2017-01-01

The interception and smoothing effect of forest canopies on pulses of incident rainfall and its delivery to the soil has been suggested as a factor in moderating peak pore water pressure in soil mantles, thus reducing the risk of shallow landslides. Here we provide 3 years of rainfall and throughfall data in a tropical secondary dipterocarp forest characterized by few large trees in northern Thailand, along with selected soil moisture dynamics, to address this issue. Throughfall was an estimated 88 % of rainfall, varying from 86 to 90 % in individual years. Data from 167 events demonstrate that canopy interception was only weakly associated (via a nonlinear relationship) with total event rainfall, but not significantly correlated with duration, mean intensity, or antecedent 2-day precipitation (API2). Mean interception during small events (≤ 35 mm) was 17 % (n = 135 events) compared with only 7 % for large events (> 35 mm; n = 32). Examining small temporal intervals within the largest and highest intensity events that would potentially trigger landslides revealed complex patterns of interception. The tropical forest canopy had little smoothing effect on incident rainfall during the largest events. During events with high peak intensities, high wind speeds, and/or moderate-to-high pre-event wetting, measured throughfall was occasionally higher than rainfall during large event peaks, demonstrating limited buffering. However, in events with little wetting and low-to-moderate wind speed, early event rainfall peaks were buffered by the canopy. As rainfall continued during most large events, there was little difference between rainfall and throughfall depths. A comparison of both rainfall and throughfall depths to conservative mean intensity-duration thresholds for landslide initiation revealed that throughfall exceeded the threshold in 75 % of the events in which rainfall exceeded the threshold for both wet and dry conditions. Throughfall intensity for the 11 largest

Interception and modification of network authentication packets with the purpose of allowing alternative authentication modes

DOEpatents

Kent, Alexander Dale [Los Alamos, NM

2008-09-02

Methods and systems in a data/computer network for authenticating identifying data transmitted from a client to a server through use of a gateway interface system which are communicately coupled to each other are disclosed. An authentication packet transmitted from a client to a server of the data network is intercepted by the interface, wherein the authentication packet is encrypted with a one-time password for transmission from the client to the server. The one-time password associated with the authentication packet can be verified utilizing a one-time password token system. The authentication packet can then be modified for acceptance by the server, wherein the response packet generated by the server is thereafter intercepted, verified and modified for transmission back to the client in a similar but reverse process.

Observations of energitic radiation bursts from thunder activities

NASA Astrophysics Data System (ADS)

Tsuchiya, H.; Enoto, T.; Torii, T.; Yuasa, T.; Yamada, S.; Kitacuhi, T.; Nakazawa, K.; Kato, H.; Okano, M.; Makishima, K.

2009-04-01

Energetic radiation bursts have been observed during strong thunderstorms by ground-based detectors as well as high-mountain ones. Those radiation bursts are thought to result from runaway electrons originating from electrons accelerated by strong electric field in lightning discharges and thunderclouds, and hence provide a valuable key to understand particle acceleration in thunder activity. Interestingly, they can be categorized into two bursts by their duration. One consists of short bursts lasting for milli-seconds or less. The other comprises long bursts having duration of a few seconds. In order to better understand both short and long bursts, we have conducted experiments at coastal area of the Japan Sea and a 2770-m altitude observatory. In this talk, we will report on those experiments, showing the two experiments has successfully observed both short and long bursts. Especially, we will focus on high-energy radiations extending over MeV energies, and then discuss a plausible model to explain how those high-energy radiations are produced in thunder activity.

An integrated ball projection technology for the study of dynamic interceptive actions.

PubMed

Stone, J A; Panchuk, D; Davids, K; North, J S; Fairweather, I; Maynard, I W

2014-12-01

Dynamic interceptive actions, such as catching or hitting a ball, are important task vehicles for investigating the complex relationship between cognition, perception, and action in performance environments. Representative experimental designs have become more important recently, highlighting the need for research methods to ensure that the coupling of information and movement is faithfully maintained. However, retaining representative design while ensuring systematic control of experimental variables is challenging, due to the traditional tendency to employ methods that typically involve use of reductionist motor responses such as buttonpressing or micromovements. Here, we outline the methodology behind a custom-built, integrated ball projection technology that allows images of advanced visual information to be synchronized with ball projection. This integrated technology supports the controlled presentation of visual information to participants while they perform dynamic interceptive actions. We discuss theoretical ideas behind the integration of hardware and software, along with practical issues resolved in technological design, and emphasize how the system can be integrated with emerging developments such as mixed reality environments. We conclude by considering future developments and applications of the integrated projection technology for research in human movement behaviors.

Low Probability of Intercept Waveforms via Intersymbol Dither Performance Under Multiple Conditions

DTIC Science & Technology

2009-03-01

United States Air Force, Department of Defense, or the United States Government . AFIT/GE/ENG/09-23 Low Probability of Intercept Waveforms via...21 D random variable governing the distribution of dither values 21 p (ct) D (t) probability density function of the...potential performance loss of a non-cooperative receiver compared to a cooperative receiver designed to account for ISI and multipath. 1.3 Thesis

Low Probability of Intercept Waveforms via Intersymbol Dither Performance Under Multipath Conditions

DTIC Science & Technology

2009-03-01

United States Air Force, Department of Defense, or the United States Government . AFIT/GE/ENG/09-23 Low Probability of Intercept Waveforms via...21 D random variable governing the distribution of dither values 21 p (ct) D (t) probability density function of the...potential performance loss of a non-cooperative receiver compared to a cooperative receiver designed to account for ISI and multipath. 1.3 Thesis

Intercept-Resend-Measure Attack Towards Quantum Private Comparison Protocol Using Genuine Four-Particle Entangled States and its Improvement

NASA Astrophysics Data System (ADS)

Pan, Hong-Ming

2018-03-01

Recently, Jia et al. proposed the quantum private comparison protocol with the genuine four-particle entangled states (Jia et al., Int. J. Theor. Phys. 51(4), 1187-1194 (2012)). Jia et al. claimed that in this protocol, TP cannot obtain Alice and Bob's secrets and only knows their comparison result. However, in this paper, we demonstrate that if TP is a genuine semi-honest third party, he can totally obtain Alice and Bob's secrets by launching a particular intercept-resend-measure attack. After suggesting the intercept-resend-measure attack strategy from TP first, we put forward one corresponding improvement to prevent this attack.

Variable-intercept panel model for deformation zoning of a super-high arch dam.

PubMed

Shi, Zhongwen; Gu, Chongshi; Qin, Dong

2016-01-01

This study determines dam deformation similarity indexes based on an analysis of deformation zoning features and panel data clustering theory, with comprehensive consideration to the actual deformation law of super-high arch dams and the spatial-temporal features of dam deformation. Measurement methods of these indexes are studied. Based on the established deformation similarity criteria, the principle used to determine the number of dam deformation zones is constructed through entropy weight method. This study proposes the deformation zoning method for super-high arch dams and the implementation steps, analyzes the effect of special influencing factors of different dam zones on the deformation, introduces dummy variables that represent the special effect of dam deformation, and establishes a variable-intercept panel model for deformation zoning of super-high arch dams. Based on different patterns of the special effect in the variable-intercept panel model, two panel analysis models were established to monitor fixed and random effects of dam deformation. Hausman test method of model selection and model effectiveness assessment method are discussed. Finally, the effectiveness of established models is verified through a case study.

Departure Trajectory Synthesis and the Intercept Problem

NASA Technical Reports Server (NTRS)

Bolender, Michael A.; Slater, G. L.

1997-01-01

Two areas of the departure problem in air traffic control are discussed. The first topic is the generation of climb-out trajectories to a fix. The trajectories would be utilized by a scheduling algorithm to allocate runways, sequence the proposed departures, and assign a departure time. The second area is concerned with finding horizontal trajectories to merge aircraft from the TRACON to an open slot in the en-route environment. Solutions are presented for the intercept problem for two cases: (1) the aircraft is traveling at the speed of the aircraft in the jetway; (2) the merging aircraft has to accelerate to reach the speed of the aircraft in the en-route stream. An algorithm is given regarding the computation of a solution for the latter case. For the former, a set of equations is given that allows us to numerically solve for the coordinate where the merge will occur.

Radiation Measurements Performed with Active Detectors Relevant for Human Space Exploration.

PubMed

Narici, Livio; Berger, Thomas; Matthiä, Daniel; Reitz, Günther

2015-01-01

A reliable radiation risk assessment in space is a mandatory step for the development of countermeasures and long-duration mission planning in human spaceflight. Research in radiobiology provides information about possible risks linked to radiation. In addition, for a meaningful risk evaluation, the radiation exposure has to be assessed to a sufficient level of accuracy. Consequently, both the radiation models predicting the risks and the measurements used to validate such models must have an equivalent precision. Corresponding measurements can be performed both with passive and active devices. The former is easier to handle, cheaper, lighter, and smaller but they measure neither the time dependence of the radiation environment nor some of the details useful for a comprehensive radiation risk assessment. Active detectors provide most of these details and have been extensively used in the International Space Station. To easily access such an amount of data, a single point access is becoming essential. This review presents an ongoing work on the development of a tool that allows obtaining information about all relevant measurements performed with active detectors providing reliable inputs for radiation model validation.

Development and testing of a snow interceptometer to quantify canopy water storage and interception processes in the rain/snow transition zone of the North Cascades, Washington, USA

NASA Astrophysics Data System (ADS)

Martin, Kael A.; Van Stan, John T.; Dickerson-Lange, Susan E.; Lutz, James A.; Berman, Jeffrey W.; Gersonde, Rolf; Lundquist, Jessica D.

2013-06-01

Tree canopy snow interception is a significant hydrological process, capable of removing up to 60% of snow from the ground snowpack. Our understanding of canopy interception has been limited by our ability to measure whole canopy water storage in an undisturbed forest setting. This study presents a relatively inexpensive technique for directly measuring snow canopy water storage using an interceptometer, adapted from Friesen et al. (2008). The interceptometer is composed of four linear motion position sensors distributed evenly around the tree trunk. We incorporate a trunk laser-mapping installation method for precise sensor placement to reduce signal error due to sensor misalignment. Through calibration techniques, the amount of canopy snow required to produce the measured displacements can be calculated. We demonstrate instrument performance on a western hemlock (Tsuga heterophylla) for a snow interception event in November 2011. We find a snow capture efficiency of 83 ± 15% of accumulated ground snowfall with a maximum storage capacity of 50 ± 8 mm snow water equivalent (SWE). The observed interception event is compared to simulated interception, represented by the variable infiltration capacity (VIC) hydrologic model. The model generally underreported interception magnitude by 33% using a leaf area index (LAI) of 5 and 16% using an LAI of 10. The interceptometer captured intrastorm accumulation and melt rates up to 3 and 0.75 mm SWE h-1, respectively, which the model failed to represent. While further implementation and validation is necessary, our preliminary results indicate that forest interception magnitude may be underestimated in maritime areas.

Microwave-photonics direction finding system for interception of low probability of intercept radio frequency signals

NASA Astrophysics Data System (ADS)

Pace, Phillip Eric; Tan, Chew Kung; Ong, Chee K.

2018-02-01

Direction finding (DF) systems are fundamental electronic support measures for electronic warfare. A number of DF techniques have been developed over the years; however, these systems are limited in bandwidth and resolution and suffer from a complex design for frequency downconversion. The design of a photonic DF technique for the detection and DF of low probability of intercept (LPI) signals is investigated. Key advantages of this design include a small baseline, wide bandwidth, high resolution, minimal space, weight, and power requirement. A robust postprocessing algorithm that utilizes the minimum Euclidean distance detector provides consistence and accurate estimation of angle of arrival (AoA) for a wide range of LPI waveforms. Experimental tests using frequency modulation continuous wave (FMCW) and P4 modulation signals were conducted in an anechoic chamber to verify the system design. Test results showed that the photonic DF system is capable of measuring the AoA of the LPI signals with 1-deg resolution over a 180 deg field-of-view. For an FMCW signal, the AoA was determined with a RMS error of 0.29 deg at 1-deg resolution. For a P4 coded signal, the RMS error in estimating the AoA is 0.32 deg at 1-deg resolution.

Constructing Graphical Representations: Middle Schoolers' Intuitions and Developing Knowledge about Slope and Y-Intercept

ERIC Educational Resources Information Center

Hattikudur, Shanta; Prather, Richard W.; Asquith, Pamela; Alibali, Martha W.; Knuth, Eric J.; Nathan, Mitchell

2012-01-01

Middle-school students are expected to understand key components of graphs, such as slope and y-intercept. However, constructing graphs is a skill that has received relatively little research attention. This study examined students' construction of graphs of linear functions, focusing specifically on the relative difficulties of graphing slope and…

How information guides movement: intercepting curved free kicks in soccer.

PubMed

Craig, Cathy M; Bastin, Julien; Montagne, Gilles

2011-10-01

Previous studies have shown that balls subjected to spin induce large errors in perceptual judgments (Craig, Berton, Rao, Fernandez, & Bootsma, 2006; Craig et al., 2009) due to the additional accelerative force that causes the ball's flight path to deviate from a standard parabolic trajectory. A recent review however, has suggested that the findings from such experiments may be imprecise due to the decoupling of perception and action and the reliance on the ventral system (van der Kamp, Rivas, van Doorn, & Savelsbergh, 2008). The aim of this study was to present the same curved free kick trajectory simulations from the perception only studies (Craig et al., 2006, 2009) but this time allow participants to move to intercept the ball. By using immersive, interactive virtual reality technology participants were asked to control the movement of a virtual effector presented in a virtual soccer stadium so that it would make contact with a virtual soccer ball as it crossed the goal-line. As in the perception only studies the direction of spin had a significant effect on the participants' responses with significantly fewer balls being intercepted in the spin conditions when compared to no-spin conditions. A significantly higher percentage of movement reversals for the spin conditions served to highlight the link between information specifying ball heading direction and subsequent movement. The coherence of the findings for both the perception and perception/action study are discussed in light of the dual systems model for visual processing. Crown Copyright © 2010. Published by Elsevier B.V. All rights reserved.

Modelling rainfall interception by a lowland tropical rain forest in northeastern Puerto Rico

Treesearch

J. Schellekensa; F.N. Scatenab; L.A. Bruijnzeela; A.J. \\t Wickela

1999-01-01

Recent surveys of tropical forest water use suggest that rainfall interception by the canopy is largest in wet maritime locations. To investigate the underlying processes at one such location—the Luquillo Experimental Forest in eastern Puerto Rico—66 days of detailed throughfall and above-canopy climatic data were collected in 1996 and analysed using the Rutter and...

Radiation Measurements Performed with Active Detectors Relevant for Human Space Exploration

PubMed Central

Narici, Livio; Berger, Thomas; Matthiä, Daniel; Reitz, Günther

2015-01-01

A reliable radiation risk assessment in space is a mandatory step for the development of countermeasures and long-duration mission planning in human spaceflight. Research in radiobiology provides information about possible risks linked to radiation. In addition, for a meaningful risk evaluation, the radiation exposure has to be assessed to a sufficient level of accuracy. Consequently, both the radiation models predicting the risks and the measurements used to validate such models must have an equivalent precision. Corresponding measurements can be performed both with passive and active devices. The former is easier to handle, cheaper, lighter, and smaller but they measure neither the time dependence of the radiation environment nor some of the details useful for a comprehensive radiation risk assessment. Active detectors provide most of these details and have been extensively used in the International Space Station. To easily access such an amount of data, a single point access is becoming essential. This review presents an ongoing work on the development of a tool that allows obtaining information about all relevant measurements performed with active detectors providing reliable inputs for radiation model validation. PMID:26697408

A passive and active microwave-vector radiative transfer (PAM-VRT) model

NASA Astrophysics Data System (ADS)

Yang, Jun; Min, Qilong

2015-11-01

A passive and active microwave vector radiative transfer (PAM-VRT) package has been developed. This fast and accurate forward microwave model, with flexible and versatile input and output components, self-consistently and realistically simulates measurements/radiation of passive and active microwave sensors. The core PAM-VRT, microwave radiative transfer model, consists of five modules: gas absorption (two line-by-line databases and four fast models); hydrometeor property of water droplets and ice (spherical and nonspherical) particles; surface emissivity (from Community Radiative Transfer Model (CRTM)); vector radiative transfer of successive order of scattering (VSOS); and passive and active microwave simulation. The PAM-VRT package has been validated against other existing models, demonstrating good accuracy. The PAM-VRT not only can be used to simulate or assimilate measurements of existing microwave sensors, but also can be used to simulate observation results at some new microwave sensors.

Anti-Smoking Practice in Hospitals: An Intercept Survey among Patients in Hubei Province, China

ERIC Educational Resources Information Center

Zhou, Dunjin; Yan, Yaqiong; Yu, Huihong; Xia, Qinghua; Yang, Niannian; Zhang, Zhifeng; Zhu, Zhaoyang; Li, Fang; Gong, Jie

2012-01-01

Purpose: This study aims to examine whether, in the opinion of patients selected in 13 hospitals of Hubei province, China, hospitals are smoke free. Patients were also asked whether their physicians had inquired about their smoking status. Design/methodology/approach: Patients were recruited through an intercept method (i.e. stopped by the…

Radiative, actively cooled panel tests results

NASA Technical Reports Server (NTRS)

Shore, C. P.; Nowak, R. J.; Sharpe, E. L.

1978-01-01

The radiative, actively cooled panel designed to withstand a uniform incident heat flux of 136 kW/sq m to a 444 K surface temperature was evaluated. The test program consisted of preliminary static thermal mechanical loading and aerothermal flow tests. Test results are briefly discussed.

Evaluation of the intercept oral specimen collection device with HIV assays versus paired serum/plasma specimens.

PubMed

Beelaert, G; Van Heddegem, L; Van Frankenhuijsen, M; Vandewalle, G; Compernolle, V; Florence, E; Fransen, K

2016-08-01

Oral fluid has many advantages over blood-based techniques: it is less invasive, eliminates the occupational risk associated with needle stick accidents and collection can be self-administrated. Each individual test is packaged with a corresponding collection device. This study tested the suitability of the Intercept Oral Specimen Collection Device for different HIV diagnostic tests: three different rapid HIV tests and two adapted ELISAs, which were evaluated and compared with a gold standard on blood. In addition a total IgG quantification was performed to demonstrate the quality of the specimen. HIV antibodies were detected with a sensitivity of 100%, 99.3%, 98.6%, 100% and 95.7% for, DPP, OraQuick, Aware, Genscreen and Vironostika respectively using the Intercept Collection Device. Respective specificities were 100%, 100%, 99.3%, 97.3% and 100%. Copyright © 2016 Elsevier B.V. All rights reserved.

Implication of Intrastorm Rainfall-Canopy Interaction on Interception Performance of Broadleaf Evergreen Shrubs in an Ultra-Urban Setting

NASA Astrophysics Data System (ADS)

Yerk, W.; Montalto, F. A.

2015-12-01

Because of its ability to intercept a portion of rainfall, vegetated canopies can play substantial role in modulating the urban hydrological cycle. However, canopy interception research has historically been focused to forest canopies. The goal of our research is to quantify rainfall partitioning by isolated evergreen shrub canopies in an ultra-urban setting. The three year field experiment involved three exemplars of cherry laurel (Prunus laurocerasus 'Otto Luyken'.) Ten rain gauges positioned under each plant were used to measure throughfall with a sampling frequency of five seconds. A number of specific techniques were implemented to minimize error associated with the gauges, e.g., splash-in, splash-out and excessive wetting. The cumulative throughfall deficit (i.e., gross precipitation minus throughfall within the canopy projected area and minus stemflow) for the periods of August-December 2013, April-December 2014 and April-July 2015 was 39%. Spatial variability of throughfall was large (coefficient of variation up to 1.5.) Stable areas of preferential throughfall flux were observed. Stemflow showed a high variability (1.4 - 24%) between rain events. The relationship between throughfall and precipitation intensity was strongly linear (adjusted coefficient of determination R2 0.79) throughout the entire range of observed rainfall intensities. The overall ratio of throughfall to precipitation intensity was 0.48:1. The observations suggest that reduction of throughfall intensity by the canopy during a rainstorm determines the aggregate interception depth. In contrast, the amount of water stored on the canopy and evaporated between and after rain events contributes minimally to interception loss. Penman-Monteith estimates of wet canopy evaporation cannot account for the throughfall deficit. Lateral displacement of microdrops beyond the canopy projected area is another phenomenon that will be discussed and most recent observations of an extended gauge network will

Saccadic interception of a moving visual target after a spatiotemporal perturbation.

PubMed

Fleuriet, Jérome; Goffart, Laurent

2012-01-11

Animals can make saccadic eye movements to intercept a moving object at the right place and time. Such interceptive saccades indicate that, despite variable sensorimotor delays, the brain is able to estimate the current spatiotemporal (hic et nunc) coordinates of a target at saccade end. The present work further tests the robustness of this estimate in the monkey when a change in eye position and a delay are experimentally added before the onset of the saccade and in the absence of visual feedback. These perturbations are induced by brief microstimulation in the deep superior colliculus (dSC). When the microstimulation moves the eyes in the direction opposite to the target motion, a correction saccade brings gaze back on the target path or very near. When it moves the eye in the same direction, the performance is more variable and depends on the stimulated sites. Saccades fall ahead of the target with an error that increases when the stimulation is applied more caudally in the dSC. The numerous cases of compensation indicate that the brain is able to maintain an accurate and robust estimate of the location of the moving target. The inaccuracies observed when stimulating the dSC that encodes the visual field traversed by the target indicate that dSC microstimulation can interfere with signals encoding the target motion path. The results are discussed within the framework of the dual-drive and the remapping hypotheses.

A street intercept survey to assess HIV-testing attitudes and behaviors.

PubMed

Rotheram-Borus, M J; Mann, T; Newman, P A; Grusky, O; Frerichs, R R; Wight, R G; Kuklinski, M

2001-06-01

Nationally, it has been estimated that 44% of adults in the United States have been tested for HIV, with substantial individual and community-level variations in HIV-testing attitudes and behaviors. HIV-testing behaviors and intentions and attitudes toward HIV testing, particularly toward home tests, were assessed among 385 adults recruited in a street intercept survey from a gay-identified agency, a substance-abuse treatment program, and inner-city community venues (a shopping mall and community center). Across these Los Angeles sites, the proportion of persons reported being tested for HIV in their lifetime (77%) was higher than the national estimate. Gay-identified agency (88%) and substance-abuse treatment program participants (99%) were more likely to have been tested than were the community participants (67%). Participants from a gay-identified agency were more likely to have had an anonymous test (51%) than were those from a substance-abuse treatment program (25%) or community sites (24%). Attitudes toward HIV testing, including mail-in home-test kits and instant home tests, were very positive. Most participants were willing to pay about $20 for a home-test kit. Participants from the community sites (82%) and the substance-abuse treatment program participants (87%) endorsed notification of HIV status to health departments and sexual partners more than did participants from the gay identified agency (48%). The street intercept survey appears to be a quick and feasible method to assess HIV testing in urban areas.

Buzzing during biosonar-based interception of prey in the delphinids Tursiops truncatus and Pseudorca crassidens.

PubMed

Wisniewska, Danuta M; Johnson, Mark; Nachtigall, Paul E; Madsen, Peter T

2014-12-15

Echolocating bats and toothed whales probe their environment with ultrasonic sound pulses, using returning echoes to navigate and find prey in a process that appears to have resulted from a remarkable convergence of the two taxa. Here, we report the first detailed quantification of echolocation behaviour during prey capture in the most studied delphinid species, a false killer whale and a bottlenose dolphin. Using acoustic DTAGs, we demonstrate that just prior to prey interception these delphinids change their acoustic gaze dramatically by reducing inter-click intervals and output >10-fold in a high repetition rate, low output buzz. Buzz click rates of 250-500 Hz for large but agile animals suggest that sampling rates during capture are scaled with the whale's manoeuvrability. These observations support the growing notion that fast sonar sampling accompanied by a low output level is critical for high rate feedback to inform motor patterns during prey interception in all echolocating toothed whales. © 2014. Published by The Company of Biologists Ltd.

Late evolution of very low mass X-ray binaries sustained by radiation from their primaries

NASA Technical Reports Server (NTRS)

Ruderman, M.; Shaham, J.; Tavani, M.; Eichler, D.

1989-01-01

The accretion-powered radiation from the X-ray pulsar system Her X-1 (McCray et al. 1982) is studied. The changes in the soft X-ray and gamma-ray flux and in the accompanying electron-positron wind are discussed. These are believed to be associated with the inward movement of the inner edge of the accretion disk corresponding to the boundary with the neutron star's corotating magnetosphere (Alfven radius). LMXB evolution which is self-sustained by secondary winds intercepting the radiation emitted near an LMXB neutron star is investigated as well.

Acetylcholine content and cholinesterase activity as related to the combined effects of allergen and radiation. [Rats, gamma radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lipshits, R.U.; Kratinova, M.A.

1977-01-01

Rats were given intraperitoneal injections of antigen and exposed to 200 R of gamma radiation. Acetylcholine content and cholinesterase activity of blood were analyzed every 5 days for 30 days. The interval between sensitization and irradiation determined the direction of changes in allergic reactions. The radiation appreciably attenuated active sensitization of rats. The degree of sensitization was related to changes in cholinergic processes. The data confirmed the assumption that cholinergic systems are involved in the mechanisms of change in allergic reactivity under the influence of radiation. (HLW)

Seed-borne Brachycladium penicillatum Intercepted under Plant Quarantine Inspection in Korea

PubMed Central

Chang, Seo-Yeon; Lee, Moon Young; Kim, Min-Kyung; Choi, Woobong

2012-01-01

A fungus detected from the importing seeds of Papaver rhoeas under plant quarantine inspection in Korea was identified as Brachycladium penicillatum Corda. It differed in morphological characteristics from a similar species, B. papaveris, which was known to form no macroconidiophores and no microsclerotia. Since the first interception in 2006, this fungus has frequently been found from importing seeds of Papaver spp. It was detected from 31 out of 282 seed consignments imported from 2006 to 2011. To prevent its introduction to Korea, the seed consignments infested by B. penicillatum were destroyed or reshipped. PMID:23115515

Height intercept for estimating site index in young ponderosa pine plantations and natural stands

Treesearch

William W. Oliver

1972-01-01

Site index is difficult to estimate with any reliability in ponderosa pine (Pinus ponderosa Laws.) stands below 20 yeas old. A method of estimating site index based on 4-year height intercepts (total length of the first four internodes above breast height) is described. Equations based on two sets of published site-index curves were developed. They...

Deficiencies of active electronic radiation protection dosimeters in pulsed fields.

PubMed

Ankerhold, U; Hupe, O; Ambrosi, P

2009-07-01

Nowadays nearly all radiation fields used for X-ray diagnostics are pulsed. These fields are characterised by a high dose rate during the pulse and a short pulse duration in the range of a few milliseconds. The use of active electronic dosimeters has increased in the past few years, but these types of dosimeters might possibly not measure reliably in pulsed radiation fields. Not only personal dosimeters but also area dosimeters that are used mainly for dose rate measurements are concerned. These cannot be substituted by using passive dosimeter types. The characteristics of active electronic dosimeters determined in a continuous radiation field cannot be transferred to those in pulsed fields. Some provisional measurements with typical electronic dosimeters in pulsed radiation fields are presented to reveal this basic problem.

Active Co-Storage of Cryogenic Propellants for Lunar Explortation

NASA Technical Reports Server (NTRS)

Mustafi, S.; Canavan, E. R.; Boyle, R. F.; Panek, J. S.; Riall, S. M.; Miller, F. K.

2008-01-01

Long-term storage of cryogenic propellants is a critical requirement for NASA's effort to return to the moon. Liquid hydrogen and liquid oxygen provide the highest specific impulse of any practical chemical propulsion system, and thus provides the greatest payload mass per unit of launch mass. Future manned missions will require vehicles with the flexibility to remain in orbit for months, necessitating long-term storage of these cryogenic liquids. For decades cryogenic scientific satellites have used dual cryogens with different temperatures to cool instruments. This technology utilizes a higher temperature cryogen to provide a stage that efficiently intercepts a large fraction of the heat that would otherwise be incident on the lower temperature cryogen. This interception reduces the boil-off of the lower temperature cryogen and increasing the overall life-time of the mission. The Active Co-Storage concept is implemented similarly; the 101 K liquid oxygen thermally shields the 24 K liquid hydrogen. A thermal radiation shield that is linked to the liquid oxygen tank shrouds the liquid hydrogen tank, thereby preventing the liquid hydrogen tank from being directly exposed to the 300 K external environment. Modern cryocooler technology can eliminate the liquid oxygen boil-off and also cool the thermal radiation shield thereby reducing the liquid hydrogen boil-off to a small fraction of the unshielded rate. The thermal radiation shield can be a simple conductive shroud or a more sophisticated but lighter Broad Area Cooling (BAC) shroud. The paper describes the design impact of an active co-storage system for the Altair Descent Vehicle. This paper also compares the spacecraft-level impacts of the conductive shroud and the BAC shroud active co-storage concepts with a passive storage option in the context of the different scales of spacecraft that will be used for the lunar exploration effort - the Altair Ascent and Descent Vehicles, the Orion, and the Ares V Earth

Children's Age-Related Speed--Accuracy Strategies in Intercepting Moving Targets in Two Dimensions

ERIC Educational Resources Information Center

Rothenberg-Cunningham, Alek; Newell, Karl M.

2013-01-01

Purpose: This study investigated the age-related speed--accuracy strategies of children, adolescents, and adults in performing a rapid striking task that allowed the self-selection of the interception position in a virtual, two-dimensional environment. Method: The moving target had curvilinear trajectories that were determined by combinations of…

Common y-intercept and single compound regressions of gas-particle partitioning data vs 1/T

NASA Astrophysics Data System (ADS)

Pankow, James F.

Confidence intervals are placed around the log Kp vs 1/ T correlation equations obtained using simple linear regressions (SLR) with the gas-particle partitioning data set of Yamasaki et al. [(1982) Env. Sci. Technol.16, 189-194]. The compounds and groups of compounds studied include the polycylic aromatic hydrocarbons phenanthrene + anthracene, me-phenanthrene + me-anthracene, fluoranthene, pyrene, benzo[ a]fluorene + benzo[ b]fluorene, chrysene + benz[ a]anthracene + triphenylene, benzo[ b]fluoranthene + benzo[ k]fluoranthene, and benzo[ a]pyrene + benzo[ e]pyrene (note: me = methyl). For any given compound, at equilibrium, the partition coefficient Kp equals ( F/ TSP)/ A where F is the particulate-matter associated concentration (ng m -3), A is the gas-phase concentration (ng m -3), and TSP is the concentration of particulate matter (μg m -3). At temperatures more than 10°C from the mean sampling temperature of 17°C, the confidence intervals are quite wide. Since theory predicts that similar compounds sorbing on the same particulate matter should possess very similar y-intercepts, the data set was also fitted using a special common y-intercept regression (CYIR). For most of the compounds, the CYIR equations fell inside of the SLR 95% confidence intervals. The CYIR y-intercept value is -18.48, and is reasonably close to the type of value that can be predicted for PAH compounds. The set of CYIR regression equations is probably more reliable than the set of SLR equations. For example, the CYIR-derived desorption enthalpies are much more highly correlated with vaporization enthalpies than are the SLR-derived desorption enthalpies. It is recommended that the CYIR approach be considered whenever analysing temperature-dependent gas-particle partitioning data.

Concurrent Transient Activation of Wnt/{beta}-Catenin Pathway Prevents Radiation Damage to Salivary Glands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hai Bo; Yang Zhenhua; Shangguan Lei

2012-05-01

Purpose: Many head and neck cancer survivors treated with radiotherapy suffer from permanent impairment of their salivary gland function, for which few effective prevention or treatment options are available. This study explored the potential of transient activation of Wnt/{beta}-catenin signaling in preventing radiation damage to salivary glands in a preclinical model. Methods and Materials: Wnt reporter transgenic mice were exposed to 15 Gy single-dose radiation in the head and neck area to evaluate the effects of radiation on Wnt activity in salivary glands. Transient Wnt1 overexpression in basal epithelia was induced in inducible Wnt1 transgenic mice before together with, after,more » or without local radiation, and then saliva flow rate, histology, apoptosis, proliferation, stem cell activity, and mRNA expression were evaluated. Results: Radiation damage did not significantly affect activity of Wnt/{beta}-catenin pathway as physical damage did. Transient expression of Wnt1 in basal epithelia significantly activated the Wnt/{beta}-catenin pathway in submandibular glands of male mice but not in those of females. Concurrent transient activation of the Wnt pathway prevented chronic salivary gland dysfunction following radiation by suppressing apoptosis and preserving functional salivary stem/progenitor cells. In contrast, Wnt activation 3 days before or after irradiation did not show significant beneficial effects, mainly due to failure to inhibit acute apoptosis after radiation. Excessive Wnt activation before radiation failed to inhibit apoptosis, likely due to extensive induction of mitosis and up-regulation of proapoptosis gene PUMA while that after radiation might miss the critical treatment window. Conclusion: These results suggest that concurrent transient activation of the Wnt/{beta}-catenin pathway could prevent radiation-induced salivary gland dysfunction.« less

Micro-Fabricated Solid-State Radiation Detectors for Active Personal Dosimetry

NASA Technical Reports Server (NTRS)

Wrbanek, John D.; Wrbanek, Susan Y.; Fralick, Gustave C.; Chen, Liang-Yu

2007-01-01

Active radiation dosimetry is important to human health and equipment functionality for space applications outside the protective environment of a space station or vehicle. This is especially true for long duration missions to the moon, where the lack of a magnetic field offers no protection from space radiation to those on extravehicular activities. In order to improve functionality, durability and reliability of radiation dosimeters for future NASA lunar missions, single crystal silicon carbide devices and scintillating fiber detectors are currently being investigated for applications in advanced extravehicular systems. For many years, NASA Glenn Research Center has led significant efforts in silicon carbide semiconductor technology research and instrumentation research for sensor applications under extreme conditions. This report summarizes the technical progress and accomplishments toward characterization of radiation-sensing components for the recommendation of their fitness for advanced dosimetry development.

Interception of rainfall and surface runoff in the Brazilian Cerrado

NASA Astrophysics Data System (ADS)

Tarso Oliveira, Paulo; Wendland, Edson; Nearing, Mark; Perea Martins, João

2014-05-01

The Brazilian Cerrado plays a fundamental role in water resources dynamics because it distributes fresh water to the largest basins in Brazil and South America. In recent decades, the native Cerrado vegetation has increasingly been replaced by agricultural crops and pasture. These land cover and land use changes have altered the hydrological processes. Meanwhile, little is known about the components of the water balance in the Brazilian Cerrado, mainly because the experimental field studies in this region are scarce or nonexistent. The objective of this study was to evaluate two hydrological processes under native Cerrado vegetation, the canopy interception (CI) and the surface runoff (R). The Cerrado physiognomy was classified as "cerrado sensu stricto denso" with an absolute density of 15,278 trees ha-1, and a basal area of 11.44 m2 ha-1. We measured the gross rainfall (P) from an automated tipping bucket rain gauge (model TB4) located in a tower with 11 m of height on the Cerrado. Throughfall (TF) was obtained from 15 automated tipping bucket rain gauges (model Davis) spread below the Cerrado vegetation and randomly relocated every month during the wet season. Stemflow (SF) was measured on 12 trees using a plastic hose wrapped around the trees trunks, sealed with neutral silicone sealant, and a bucket to store the water. The canopy interception was computed by the difference between P and the sum of TF and SF. Surface runoff under undisturbed Cerrado was collected in three plots of 100 m2(5 x 20 m) in size and slope steepness of approximately 0.09 m m-1. The experimental study was conducted between January 2012 and November 2013. We found TF of 81.0% of P and SF of 1.6% of P, i.e. the canopy interception was calculated at 17.4% of P. There was a statistically significant correlation (p < 0.05) between gross rainfall and TF, SF, and CI with correlation coefficients r > 0.8. Our results suggest that the rainfall intensity, the characteristics of the trees trunks

Mapping Time-to-Contact and Time-to-Peak Effector Velocity in Interceptive Striking Tasks

ERIC Educational Resources Information Center

Rothenberg-Cunningham, Alek; Newell, Karl M.

2015-01-01

Purpose: This study investigated perception and action coupling as reflected in a mapping between time-to-contact (TTC) and time-to-peak-velocity (TPV) for children and youths aged 7 to 8, 11 to 12, and 15 to 16 years old and adults aged 19 to 20 years old performing a task that allowed the participants to self-select the interception position in…

Single mimivirus particles intercepted and imaged with an X-ray laser (CXIDB ID 1)

DOE Data Explorer

Seibert, M. Marvin; Ekeberg, Tomas; Maia, Filipe R.N.C.

2011-02-02

These are the files used to reconstruct the images in the paper "Single Mimivirus particles intercepted and imaged with an X-ray laser". Besides the diffracted intensities, the Hawk configuration files used for the reconstructions are also provided. The files from CXIDB ID 1 are the pattern and configuration files for the pattern showed in Figure 2a in the paper.

Single mimivirus particles intercepted and imaged with an X-ray laser (CXIDB ID 2)

DOE Data Explorer

Seibert, M. Marvin; Ekeberg, Tomas

2011-02-02

These are the files used to reconstruct the images in the paper "Single Mimivirus particles intercepted and imaged with an X-ray laser". Besides the diffracted intensities, the Hawk configuration files used for the reconstructions are also provided. The files from CXIDB ID 2 are the pattern and configuration files for the pattern showed in Figure 2b in the paper.

Activation of Protease Activated Receptor 2 by Exogenous Agonist Exacerbates Early Radiation Injury in Rat Intestine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang Junru; Boerma, Marjan; Kulkarni, Ashwini

2010-07-15

Purpose: Protease-activated receptor-2 (PAR{sub 2}) is highly expressed throughout the gut and regulates the inflammatory, mitogenic, fibroproliferative, and nociceptive responses to injury. PAR{sub 2} is strikingly upregulated and exhibits increased activation in response to intestinal irradiation. We examined the mechanistic significance of radiation enteropathy development by assessing the effect of exogenous PAR{sub 2} activation. Methods and Materials: Rat small bowel was exposed to localized single-dose radiation (16.5 Gy). The PAR{sub 2} agonist (2-furoyl-LIGRLO-NH{sub 2}) or vehicle was injected intraperitoneally daily for 3 days before irradiation (before), for 7 days after irradiation (after), or both 3 days before and 7 daysmore » after irradiation (before-after). Early and delayed radiation enteropathy was assessed at 2 and 26 weeks after irradiation using quantitative histologic examination, morphometry, and immunohistochemical analysis. Results: The PAR{sub 2} agonist did not elicit changes in the unirradiated (shielded) intestine. In contrast, in the irradiated intestine procured 2 weeks after irradiation, administration of the PAR{sub 2} agonist was associated with more severe mucosal injury and increased intestinal wall thickness in all three treatment groups (p <.05) compared with the vehicle-treated controls. The PAR{sub 2} agonist also exacerbated the radiation injury score, serosal thickening, and mucosal inflammation (p <.05) in the before and before-after groups. The short-term exogenous activation of PAR{sub 2} did not affect radiation-induced intestinal injury at 26 weeks. Conclusion: The results of the present study support a role for PAR{sub 2} activation in the pathogenesis of early radiation-induced intestinal injury. Pharmacologic PAR{sub 2} antagonists might have the potential to reduce the intestinal side effects of radiotherapy and/or as countermeasures in radiologic accidents or terrorism scenarios.« less

An analysis of arthropod interceptions by APHIS-PPQ and Customs and Border Patrol in Puerto Rico

USDA-ARS?s Scientific Manuscript database

USDA Animal Plant Health Inspection Service Plant Protection and Quarantine (APHIS-PPQ) and Customs and Border Patrol (CBP) inspect traffic entering the United States for arthropods that pose a threat to national agriculture and/or ecosystems. We analyzed interceptions made by these agencies in Puer...

A comparison of cover calculation techniques for relating point-intercept vegetation sampling to remote sensing imagery

USDA-ARS?s Scientific Manuscript database

Accurate and timely spatial predictions of vegetation cover from remote imagery are an important data source for natural resource management. High-quality in situ data are needed to develop and validate these products. Point-intercept sampling techniques are a common method for obtaining quantitativ...

Action specificity increases anticipatory performance and the expert advantage in natural interceptive tasks.

PubMed

Mann, David L; Abernethy, Bruce; Farrow, Damian

2010-09-01

The relationship between perception-action coupling and anticipatory skill in an interceptive task was examined using an in-situ temporal occlusion paradigm. Skilled and novice cricket batsmen were required to predict the direction of balls bowled towards them under four counterbalanced response conditions of increasing perception-action coupling: (i) verbal, (ii) lower-body movement only, (iii) full-body movement (no bat), and (iv) full-body movement with bat (i.e., the usual batting response). Skilled but not novice anticipation was found to improve as a function of coupling when responses were based on either no ball-flight, or early ball-flight information, with a response requiring even the lowest degree of body movement found to enhance anticipation when compared to a verbal prediction. Most importantly, a full-body movement using a bat elicited greater anticipation than an equivalent movement with no bat. This result highlights the important role that the requirement and/or opportunity to make bat-ball interception may play in eliciting skill differences for anticipation. Results verify the importance of using experimental conditions and task demands that closely reflect the natural performance environment in order to reveal the full nature of the expert advantage. 2010. Published by Elsevier B.V. All rights reserved.

Ultrasonic Power Output Measurement by Pulsed Radiation Pressure

PubMed Central

Fick, Steven E.; Breckenridge, Franklin R.

1996-01-01

Direct measurements of time-averaged spatially integrated output power radiated into reflectionless water loads can be made with high accuracy using techniques which exploit the radiation pressure exerted by sound on all objects in its path. With an absorptive target arranged to intercept the entirety of an ultrasound beam, total beam power can be determined as accurately as the radiation force induced on the target can be measured in isolation from confounding forces due to buoyancy, streaming, surface tension, and vibration. Pulse modulation of the incident ultrasound at a frequency well above those characteristics of confounding phenomena provides the desired isolation and other significant advantages in the operation of the radiation force balance (RFB) constructed in 1974. Equipped with purpose-built transducers and electronics, the RFB is adjusted to equate the radiation force and a counterforce generated by an actuator calibrated against reference masses using direct current as the transfer variable. Improvements made during its one overhaul in 1988 have nearly halved its overall measurement uncertainty and extended the capabilities of the RFB to include measuring the output of ultrasonic systems with arbitrary pulse waveforms. PMID:27805084

Electron-positron pairs, Compton reflection, and the X-ray spectra of active galactic nuclei

NASA Technical Reports Server (NTRS)

Zdziarski, Andrzej A.; Ghisellini, Gabriele; George, Ian M.; Fabian, A. C.; Svensson, Roland; Done, Chris

1990-01-01

It is shown here that reprocessing of radiation fron nonthermal pair cascades by cold material in the central parts of active galactic nuclei (AGN) gives rise to X-ray and gamma-ray spectra that satisfy current observational constraints. An average 1-30 keV X-ray spectral index alpha(x) of about 0.7 in the compact range 30-300 is obtained for a wide range of Lorentz factors of the injected electrons. The gamma-ray spectra are steep, with alpha(gamma) about two, and satisfy the observational constraints. Radiation from pair cascades exhibits steep power law decreases in soft X-rays similar to those observed in AGN. The overall picture is consistent with AGN having an accretion disk which intercepts and reprocesses a substantial fraction of the nonthermal continuum incident upon it from above and below.

Coherence of structural visual cues and pictorial gravity paves the way for interceptive actions.

PubMed

Zago, Myrka; La Scaleia, Barbara; Miller, William L; Lacquaniti, Francesco

2011-09-20

Dealing with upside-down objects is difficult and takes time. Among the cues that are critical for defining object orientation, the visible influence of gravity on the object's motion has received limited attention. Here, we manipulated the alignment of visible gravity and structural visual cues between each other and relative to the orientation of the observer and physical gravity. Participants pressed a button triggering a hitter to intercept a target accelerated by a virtual gravity. A factorial design assessed the effects of scene orientation (normal or inverted) and target gravity (normal or inverted). We found that interception was significantly more successful when scene direction was concordant with target gravity direction, irrespective of whether both were upright or inverted. This was so independent of the hitter type and when performance feedback to the participants was either available (Experiment 1) or unavailable (Experiment 2). These results show that the combined influence of visible gravity and structural visual cues can outweigh both physical gravity and viewer-centered cues, leading to rely instead on the congruence of the apparent physical forces acting on people and objects in the scene.

Spacecraft intercept guidance using zero effort miss steering

NASA Astrophysics Data System (ADS)

Newman, Brett

The suitability of proportional navigation, or an equivalent zero effort miss formulation, for spacecraft intercepts during midcourse guidance, followed by a ballistic coast to the endgame, is addressed. The problem is formulated in terms of relative motion in a general 3D framework. The proposed guidance law for the commanded thrust vector orientation consists of the sum of two terms: (1) along the line of sight unit direction and (2) along the zero effort miss component perpendicular to the line of sight and proportional to the miss itself and a guidance gain. If the guidance law is to be suitable for longer range targeting applications with significant ballistic coasting after burnout, determination of the zero effort miss must account for the different gravitational accelerations experienced by each vehicle. The proposed miss determination techniques employ approximations for the true differential gravity effect. Theoretical results are applied to a numerical engagement scenario and the resulting performance is evaluated in terms of the miss distances determined from nonlinear simulation.

NLRP3 inflammasome activation mediates radiation-induced pyroptosis in bone marrow-derived macrophages

PubMed Central

Liu, Yan-gang; Chen, Ji-kuai; Zhang, Zi-teng; Ma, Xiu-juan; Chen, Yong-chun; Du, Xiu-ming; Liu, Hong; Zong, Ying; Lu, Guo-cai

2017-01-01

A limit to the clinical benefit of radiotherapy is not an incapacity to eliminate tumor cells but rather a limit on its capacity to do so without destroying normal tissue and inducing inflammation. Recent evidence reveals that the inflammasome is essential for mediating radiation-induced cell and tissue damage. In this study, using primary cultured bone marrow-derived macrophages (BMDM) and a mouse radiation model, we explored the role of NLRP3 inflammasome activation and the secondary pyroptosis underlying radiation-induced immune cell death. We observed an increasing proportion of pyroptosis and elevating Caspase-1 activation in 10 and 20 Gy radiation groups. Nlrp3 knock out significantly diminished the quantity of cleaved-Caspase-1 (p10) and IL-1β as well as the proportion of pyroptosis. Additionally, in vivo research shows that 9.5 Gy of radiation promotes Caspase-1 activation in marginal zone cells and induces death in mice, both of which can be significantly inhibited by knocking out Nlrp3. Thus, based on these findings, we conclude that the NLRP3 inflammasome activation mediates radiation-induced pyroptosis in BMDMs. Targeting NLRP3 inflammasome and pyroptosis may serve as effective strategies to diminish injury caused by radiation. PMID:28151471

Photocatalytic Active Radiation Measurements and Use

NASA Technical Reports Server (NTRS)

Davis, Bruce A.; Underwood, Lauren W.

2011-01-01

Photocatalytic materials are being used to purify air, to kill microbes, and to keep surfaces clean. A wide variety of materials are being developed, many of which have different abilities to absorb various wavelengths of light. Material variability, combined with both spectral illumination intensity and spectral distribution variability, will produce a wide range of performance results. The proposed technology estimates photocatalytic active radiation (PcAR), a unit of radiation that normalizes the amount of light based on its spectral distribution and on the ability of the material to absorb that radiation. Photocatalytic reactions depend upon the number of electron-hole pairs generated at the photocatalytic surface. The number of electron-hole pairs produced depends on the number of photons per unit area per second striking the surface that can be absorbed and whose energy exceeds the bandgap of the photocatalytic material. A convenient parameter to describe the number of useful photons is the number of moles of photons striking the surface per unit area per second. The unit of micro-einsteins (or micromoles) of photons per m2 per sec is commonly used for photochemical and photoelectric-like phenomena. This type of parameter is used in photochemistry, such as in the conversion of light energy for photosynthesis. Photosynthetic response correlates with the number of photons rather than by energy because, in this photochemical process, each molecule is activated by the absorption of one photon. In photosynthesis, the number of photons absorbed in the 400 700 nm spectral range is estimated and is referred to as photosynthetic active radiation (PAR). PAR is defined in terms of the photosynthetic photon flux density measured in micro-einsteins of photons per m2 per sec. PcAR is an equivalent, similarly modeled parameter that has been defined for the photocatalytic processes. Two methods to measure the PcAR level are being proposed. In the first method, a calibrated

Pathogen inactivation efficacy of Mirasol PRT System and Intercept Blood System for non-leucoreduced platelet-rich plasma-derived platelets suspended in plasma.

PubMed

Kwon, S Y; Kim, I S; Bae, J E; Kang, J W; Cho, Y J; Cho, N S; Lee, S W

2014-10-01

This study was conducted to evaluate the efficacy of pathogen inactivation (PI) in non-leucoreduced platelet-rich plasma-derived platelets suspended in plasma using the Mirasol PRT System and the Intercept Blood System. Platelets were pooled using the Acrodose PL system and separated into two aliquots for Mirasol and Intercept treatment. Four replicates of each viral strain were used for the evaluation. For bacteria, both low-titre (45-152 CFU/unit) inoculation and high-titre (7·34-10·18 log CFU/unit) inoculation with two replicates for each bacterial strain were used. Platelets with non-detectable bacterial growth and platelets inoculated with a low titre were stored for 5 days, and culture was performed with the BacT/ALERT system. The inactivation efficacy expressed as log reduction for Mirasol and Intercept systems for viruses was as follows: human immunodeficiency virus 1, ≥4·19 vs. ≥4·23; bovine viral diarrhoea virus, 1·83 vs. ≥6·03; pseudorabies virus, 2·73 vs. ≥5·20; hepatitis A virus, 0·62 vs. 0·76; and porcine parvovirus, 0·28 vs. 0·38. The inactivation efficacy for bacteria was as follows: Escherichia coli, 5·45 vs. ≥9·22; Staphylococcus aureus, 4·26 vs. ≥10·11; and Bacillus subtilis, 5·09 vs. ≥7·74. Postinactivation bacterial growth in platelets inoculated with a low titre of S. aureus or B. subtilis was detected only with Mirasol. Pathogen inactivation efficacy of Intercept for enveloped viruses was found to be satisfactory. Mirasol showed satisfactory inactivation efficacy for HIV-1 only. The two selected non-enveloped viruses were not inactivated by both systems. Inactivation efficacy of Intercept was more robust for all bacteria tested at high or low titres. © 2014 International Society of Blood Transfusion.

High resolution amorphous silicon radiation detectors

DOEpatents

Street, R.A.; Kaplan, S.N.; Perez-Mendez, V.

1992-05-26

A radiation detector employing amorphous Si:H cells in an array with each detector cell having at least three contiguous layers (n-type, intrinsic, p-type), positioned between two electrodes to which a bias voltage is applied. An energy conversion layer atop the silicon cells intercepts incident radiation and converts radiation energy to light energy of a wavelength to which the silicon cells are responsive. A read-out device, positioned proximate to each detector element in an array allows each such element to be interrogated independently to determine whether radiation has been detected in that cell. The energy conversion material may be a layer of luminescent material having a columnar structure. In one embodiment a column of luminescent material detects the passage therethrough of radiation to be detected and directs a light beam signal to an adjacent a-Si:H film so that detection may be confined to one or more such cells in the array. One or both electrodes may have a comb structure, and the teeth of each electrode comb may be interdigitated for capacitance reduction. The amorphous Si:H film may be replaced by an amorphous Si:Ge:H film in which up to 40 percent of the amorphous material is Ge. Two dimensional arrays may be used in X-ray imaging, CT scanning, crystallography, high energy physics beam tracking, nuclear medicine cameras and autoradiography. 18 figs.

High resolution amorphous silicon radiation detectors

DOEpatents

Street, Robert A.; Kaplan, Selig N.; Perez-Mendez, Victor

1992-01-01

A radiation detector employing amorphous Si:H cells in an array with each detector cell having at least three contiguous layers (n type, intrinsic, p type), positioned between two electrodes to which a bias voltage is applied. An energy conversion layer atop the silicon cells intercepts incident radiation and converts radiation energy to light energy of a wavelength to which the silicon cells are responsive. A read-out device, positioned proximate to each detector element in an array allows each such element to be interrogated independently to determine whether radiation has been detected in that cell. The energy conversion material may be a layer of luminescent material having a columnar structure. In one embodiment a column of luminescent material detects the passage therethrough of radiation to be detected and directs a light beam signal to an adjacent a-Si:H film so that detection may be confined to one or more such cells in the array. One or both electrodes may have a comb structure, and the teeth of each electrode comb may be interdigitated for capacitance reduction. The amorphous Si:H film may be replaced by an amorphous Si:Ge:H film in which up to 40 percent of the amorphous material is Ge. Two dimensional arrays may be used in X-ray imaging, CT scanning, crystallography, high energy physics beam tracking, nuclear medicine cameras and autoradiography.

Active Radiative Thermal Switching with Graphene Plasmon Resonators.

PubMed

Ilic, Ognjen; Thomas, Nathan H; Christensen, Thomas; Sherrott, Michelle C; Soljačić, Marin; Minnich, Austin J; Miller, Owen D; Atwater, Harry A

2018-03-27

We theoretically demonstrate a near-field radiative thermal switch based on thermally excited surface plasmons in graphene resonators. The high tunability of graphene enables substantial modulation of near-field radiative heat transfer, which, when combined with the use of resonant structures, overcomes the intrinsically broadband nature of thermal radiation. In canonical geometries, we use nonlinear optimization to show that stacked graphene sheets offer improved heat conductance contrast between "ON" and "OFF" switching states and that a >10× higher modulation is achieved between isolated graphene resonators than for parallel graphene sheets. In all cases, we find that carrier mobility is a crucial parameter for the performance of a radiative thermal switch. Furthermore, we derive shape-agnostic analytical approximations for the resonant heat transfer that provide general scaling laws and allow for direct comparison between different resonator geometries dominated by a single mode. The presented scheme is relevant for active thermal management and energy harvesting as well as probing excited-state dynamics at the nanoscale.

Measuring forest floor evaporation from interception in prescribed burned forests in Southern Italy.

NASA Astrophysics Data System (ADS)

Giuditta, Elisabetta; Coenders-Gerrits, Miriam; Bogaard, Thom; Wenninger, Jochen; Greco, Roberto; Ialongo, Gianluca; Esposito, Assunta; Rutigliano, Flora Angela

2016-04-01

Wildfires are one of the major environmental issue in the Mediterranean area. Prescribed burning (PB) is increasingly used in Europe as a practice to reduce fire risk, through dead fine fuel reduction. Several studies have focused on fire effects on vegetation and soil microbial community, but very few on ecosystem processes involved in water cycle. This study aims to estimate interception by the litter and fermentation layer and the successive evaporation flux in laboratory conditions, using a water balance and 2H and 18O isotopes mass balance calculation, in order to assess PB effects on the hydrology and ecosystem in pine plantations. PB was carried out in spring 2014 in three pine plantations of Southern Italy, dominated by Pinus halepensis (Cilento, Vallo di Diano e Alburni National Park, CVDANP), P. pinaster (Vesuvio National Park, VNP) and P. pinea (Castel Volturno Nature Reserve, CVNR). A dataset concerning the effects of PB on vegetation structure, floristic composition, microbial biomass and activity in the fermentation layer and 5-cm of soil beneath is available for the same stands. In each plantation, two cores of litter and fermentation layer were sampled in a burned area and in a near unburned area (control), respectively, with a collector to extract an "undisturbed" core. Then, each core was transferred in a lysimeter installed in the Water Lab of Delft University of Technology. In total, three lysimeters were set up and each experiment was carried out in duplicate. The laboratory had constant temperature, and both temperature and relative humidity were recorded every 15 minutes. To simulate rainfall, ~1 litre of tap water was sprinkled uniformly on the lysimeter with a plant spray (equivalent to 32 mm of rain). The precipitation was sprinkled every 3 days for a period of two months. Soil moisture and temperature were measured during the experiment every 15 minutes in the top and bottom of the litter and fermentation layer. Interception water was

Familiar trajectories facilitate the interpretation of physical forces when intercepting a moving target.

PubMed

Mijatović, Antonija; La Scaleia, Barbara; Mercuri, Nicola; Lacquaniti, Francesco; Zago, Myrka

2014-12-01

Familiarity with the visual environment affects our expectations about the objects in a scene, aiding in recognition and interaction. Here we tested whether the familiarity with the specific trajectory followed by a moving target facilitates the interpretation of the effects of underlying physical forces. Participants intercepted a target sliding down either an inclined plane or a tautochrone. Gravity accelerated the target by the same amount in both cases, but the inclined plane represented a familiar trajectory whereas the tautochrone was unfamiliar to the participants. In separate sessions, the gravity field was consistent with either natural gravity or artificial reversed gravity. Target motion was occluded from view over the last segment. We found that the responses in the session with unnatural forces were systematically delayed relative to those with natural forces, but only for the inclined plane. The time shift is consistent with a bias for natural gravity, in so far as it reflects an a priori expectation that a target not affected by natural forces will arrive later than one accelerated downwards by gravity. Instead, we did not find any significant time shift with unnatural forces in the case of the tautochrone. We argue that interception of a moving target relies on the integration of the high-level cue of trajectory familiarity with low-level cues related to target kinematics.

Nitrogen and plant population change radiation capture and utilization capacity of sunflower in semi-arid environment.

PubMed

Awais, Muhammad; Wajid, Aftab; Bashir, Muhammad Usman; Habib-Ur-Rahman, Muhammad; Raza, Muhammad Aown Sammar; Ahmad, Ashfaq; Saleem, Muhammad Farrukh; Hammad, Hafiz Mohkum; Mubeen, Muhammad; Saeed, Umer; Arshad, Muhammad Naveed; Fahad, Shah; Nasim, Wajid

2017-07-01

The combination of nitrogen and plant population expresses the spatial distribution of crop plants. The spatial distribution influences canopy structure and development, radiation capture, accumulated intercepted radiation (Sa), radiation use efficiency (RUE), and subsequently dry matter production. We hypothesized that the sunflower crop at higher plant populations and nitrogen (N) rates would achieve early canopy cover, capture more radiant energy, utilize radiation energy more efficiently, and ultimately increase economic yield. To investigate the above hypothesis, we examined the influences of leaf area index (LAI) at different plant populations (83,333, 66,666, and 55,555 plants ha -1 ) and N rates (90, 120, and 150 kg ha -1 ) on radiation interception (Fi), photosynthetically active radiation (PAR) accumulation (Sa), total dry matter (TDM), achene yield (AY), and RUE of sunflower. The experimental work was conducted during 2012 and 2013 on sandy loam soil in Punjab, Pakistan. The sunflower crop captured more than 96% of incident radiant energy (mean of all treatments), 98% with a higher plant population (83,333 plants ha -1 ), and 97% with higher N application (150 kg ha -1 ) at the fifth harvest (60 days after sowing) during both study years. The plant population of 83,333 plants ha -1 with 150 kg N ha -1 ominously promoted crop, RUE, and finally productivity of sunflower (AY and TDM). Sunflower canopy (LAI) showed a very close and strong association with Fi (R 2  = 0.99 in both years), PAR (R 2  = 0.74 and 0.79 in 2012 and 2013, respectively), TDM (R 2  = 0.97 in 2012 and 0.91 in 2013), AY (R 2  = 0.95 in both years), RUE for TDM (RUE TDM ) (R 2  = 0.63 and 0.71 in 2012 and 2013, respectively), and RUE for AY (RUE AY ) (R 2  = 0.88 and 0.87 in 2012 and 2013, respectively). Similarly, AY (R 2  = 0.73 in 2012 and 0.79 in 2013) and TDM (R 2  = 0.75 in 2012 and 0.84 in 2013) indicated significant dependence on PAR accumulation of

Betatron radiation based diagnostics for plasma wakefield accelerated electron beams at the SPARC_LAB test facility

NASA Astrophysics Data System (ADS)

Shpakov, V.; Anania, M. P.; Biagioni, A.; Chiadroni, E.; Cianchi, A.; Curcio, A.; Dabagov, S.; Ferrario, M.; Filippi, F.; Marocchino, A.; Paroli, B.; Pompili, R.; Rossi, A. R.; Zigler, A.

2016-09-01

Recent progress with wake-field acceleration has shown a great potential in providing high gradient acceleration fields, while the quality of the beams remains relatively poor. Precise knowledge of the beam size at the exit from the plasma and matching conditions for the externally injected beams are the key for improvement of beam quality. Betatron radiation emitted by the beam during acceleration in the plasma is a powerful tool for the transverse beam size measurement, being also non-intercepting. In this work we report on the technical solutions chosen at SPARC_LAB for such diagnostics tool, along with expected parameters of betatron radiation.

Effectiveness Evaluation Method of Anti-Radiation Missile against Active Decoy

NASA Astrophysics Data System (ADS)

Tang, Junyao; Cao, Fei; Li, Sijia

2017-06-01

In the problem of anti-radiation missile against active decoy, whether the ARM can effectively kill the target radiation source and bait is an important index for evaluating the operational effectiveness of the missile. Aiming at this problem, this paper proposes a method to evaluate the effect of ARM against active decoy. Based on the calculation of ARM’s ability to resist the decoy, the paper proposes a method to evaluate the decoy resistance based on the key components of the hitting radar. The method has the advantages of scientific and reliability.

Parylene-based active micro space radiator with thermal contact switch

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ueno, Ai; Suzuki, Yuji

2014-03-03

Thermal management is crucial for highly functional spacecrafts exposed to large fluctuations of internal heat dissipation and/or thermal boundary conditions. Since thermal radiation is the only means for heat removal, effective control of radiation is required for advanced space missions. In the present study, a MEMS (Micro Electro Mechanical Systems) active radiator using the contact resistance change has been proposed. Unlike previous bulky thermal louvers/shutters, higher fill factor can be accomplished with an array of electrostatically driven micro diaphragms suspended with polymer tethers. With an early prototype developed with parylene MEMS technologies, radiation heat flux enhancement up to 42% hasmore » been achieved.« less

Monolithic active pixel radiation detector with shielding techniques

DOEpatents

Deptuch, Grzegorz W.

2018-03-20

A monolithic active pixel radiation detector including a method of fabricating thereof. The disclosed radiation detector can include a substrate comprising a silicon layer upon which electronics are configured. A plurality of channels can be formed on the silicon layer, wherein the plurality of channels are connected to sources of signals located in a bulk part of the substrate, and wherein the signals flow through electrically conducting vias established in an isolation oxide on the substrate. One or more nested wells can be configured from the substrate, wherein the nested wells assist in collecting charge carriers released in interaction with radiation and wherein the nested wells further separate the electronics from the sensing portion of the detector substrate. The detector can also be configured according to a thick SOA method of fabrication.

Monolithic active pixel radiation detector with shielding techniques

DOEpatents

Deptuch, Grzegorz W.

2016-09-06

A monolithic active pixel radiation detector including a method of fabricating thereof. The disclosed radiation detector can include a substrate comprising a silicon layer upon which electronics are configured. A plurality of channels can be formed on the silicon layer, wherein the plurality of channels are connected to sources of signals located in a bulk part of the substrate, and wherein the signals flow through electrically conducting vias established in an isolation oxide on the substrate. One or more nested wells can be configured from the substrate, wherein the nested wells assist in collecting charge carriers released in interaction with radiation and wherein the nested wells further separate the electronics from the sensing portion of the detector substrate. The detector can also be configured according to a thick SOA method of fabrication.

Top-Level Players' Visual Control of Interceptive Actions: Bootsma and Van Wieringen (1990) 20 Years Later

ERIC Educational Resources Information Center

Bootsma, Reinoud J.; Fernandez, Laure; Morice, Antoine H. P.; Montagne, Gilles

2010-01-01

Using a two-step approach, Van Soest et al. (2010) recently questioned the pertinence of the conclusions drawn by Bootsma and Van Wieringen (1990) with respect to the visual regulation of an exemplary rapid interceptive action: the attacking forehand drive in table tennis. In the first step, they experimentally compared the movement behaviors of…

A unifying framework for marginalized random intercept models of correlated binary outcomes

PubMed Central

Swihart, Bruce J.; Caffo, Brian S.; Crainiceanu, Ciprian M.

2013-01-01

We demonstrate that many current approaches for marginal modeling of correlated binary outcomes produce likelihoods that are equivalent to the copula-based models herein. These general copula models of underlying latent threshold random variables yield likelihood-based models for marginal fixed effects estimation and interpretation in the analysis of correlated binary data with exchangeable correlation structures. Moreover, we propose a nomenclature and set of model relationships that substantially elucidates the complex area of marginalized random intercept models for binary data. A diverse collection of didactic mathematical and numerical examples are given to illustrate concepts. PMID:25342871

Analytical-HZETRN Model for Rapid Assessment of Active Magnetic Radiation Shielding

NASA Technical Reports Server (NTRS)

Washburn, S. A.; Blattnig, S. R.; Singleterry, R. C.; Westover, S. C.

2014-01-01

The use of active radiation shielding designs has the potential to reduce the radiation exposure received by astronauts on deep-space missions at a significantly lower mass penalty than designs utilizing only passive shielding. Unfortunately, the determination of the radiation exposure inside these shielded environments often involves lengthy and computationally intensive Monte Carlo analysis. In order to evaluate the large trade space of design parameters associated with a magnetic radiation shield design, an analytical model was developed for the determination of flux inside a solenoid magnetic field due to the Galactic Cosmic Radiation (GCR) radiation environment. This analytical model was then coupled with NASA's radiation transport code, HZETRN, to account for the effects of passive/structural shielding mass. The resulting model can rapidly obtain results for a given configuration and can therefore be used to analyze an entire trade space of potential variables in less time than is required for even a single Monte Carlo run. Analyzing this trade space for a solenoid magnetic shield design indicates that active shield bending powers greater than 15 Tm and passive/structural shielding thicknesses greater than 40 g/cm2 have a limited impact on reducing dose equivalent values. Also, it is shown that higher magnetic field strengths are more effective than thicker magnetic fields at reducing dose equivalent.

Clinical Advances of Hypoxia-Activated Prodrugs in Combination With Radiation Therapy.

PubMed

Mistry, Ishna N; Thomas, Matthew; Calder, Ewen D D; Conway, Stuart J; Hammond, Ester M

2017-08-01

With the increasing incidence of cancer worldwide, the need for specific, effective therapies is ever more urgent. One example of targeted cancer therapeutics is hypoxia-activated prodrugs (HAPs), also known as bioreductive prodrugs. These prodrugs are inactive in cells with normal oxygen levels but in hypoxic cells (with low oxygen levels) undergo chemical reduction to the active compound. Hypoxia is a common feature of solid tumors and is associated with a more aggressive phenotype and resistance to all modes of therapy. Therefore, the combination of radiation therapy and bioreductive drugs presents an attractive opportunity for synergistic effects, because the HAP targets the radiation-resistant hypoxic cells. Hypoxia-activated prodrugs have typically been precursors of DNA-damaging agents, but a new generation of molecularly targeted HAPs is emerging. By targeting proteins associated with tumorigenesis and survival, these compounds may result in greater selectivity over healthy tissue. We review the clinical progress of HAPs as adjuncts to radiation therapy and conclude that the use of HAPs alongside radiation is vastly underexplored at the clinical level. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

The use of an active controlled enclosure to attenuate sound radiation from a heavy radiator

NASA Astrophysics Data System (ADS)

Sun, Yao; Yang, Tiejun; Zhu, Minggang; Pan, Jie

2017-03-01

Active structural acoustical control usually experiences difficulty in the control of heavy sources or sources where direct applications of control forces are not practical. To overcome this difficulty, an active controlled enclosure, which forms a cavity with both flexible and open boundary, is employed. This configuration permits indirect implementation of active control in which the control inputs can be applied to subsidiary structures other than the sources. To determine the control effectiveness of the configuration, the vibro-acoustic behavior of the system, which consists of a top plate with an open, a sound cavity and a source panel, is investigated in this paper. A complete mathematical model of the system is formulated involving modified Fourier series formulations and the governing equations are solved using the Rayleigh-Ritz method. The coupling mechanisms of a partly opened cavity and a plate are analysed in terms of modal responses and directivity patterns. Furthermore, to attenuate sound power radiated from both the top panel and the open, two strategies are studied: minimizing the total radiated power and the cancellation of volume velocity. Moreover, three control configurations are compared, using a point force on the control panel (structural control), using a sound source in the cavity (acoustical control) and applying hybrid structural-acoustical control. In addition, the effects of boundary condition of the control panel on the sound radiation and control performance are discussed.

Effect of active-region “volume” on the radiative properties of laser heterostructures with radiation output through the substrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nekorkin, S. M.; Zvonkov, B. N.; Baidus, N. V.

2017-01-15

The radiative properties of InGaAs/GaAs/InGaP laser structures with radiation output through the substrate depending on the number of quantum wells in the active region and laser diodes on their basis are investigated. It is established that the presence of six–eight quantum wells in the active region is optimum from the viewpoint of observable values of the threshold current and the output optical power of lasers.

HOWARD FORK ACID ROCK DRAINAGE SOURCE INTERCEPTION STUDY; HOWARD FORK OF THE SAN MIGUEL RIVER NEAR OPHIR, COLORADO

EPA Science Inventory

This project proposes to analyze regional hydrogeology as it relates to mine workings which discharge significant heavy metals into the Howard Fork of the San Miguel River and recommend strategies to intercept and divert water away from mineralized zones. The study also includes...

Reaction of Rhyolitic Magma to its Interception by the IDDP-1 Well, Krafla, 2009

NASA Astrophysics Data System (ADS)

Saubin, É.; Kennedy, B.; Tuffen, H.; Villeneuve, M.; Watson, T.; Nichols, A. R.; Schipper, I.; Cole, J. W.; Mortensen, A. K.; Zierenberg, R. A.

2017-12-01

The unexpected encounter of rhyolitic magma during IDDP-1 geothermal borehole drilling at Krafla, Iceland in 2009, temporarily created the world's hottest geothermal well. This allowed new questions to be addressed. i) How does magma react to drilling? ii) Are the margins of a magma chamber suitable for long-term extraction of supercritical fluids? To investigate these questions, we aim to reconstruct the degassing and deformation behaviour of the enigmatic magma by looking for correlations between textures in rhyolitic material retrieved from the borehole and the recorded drilling data. During drilling, difficulties were encountered in two zones, at 2070 m and below 2093 m depth. Drilling parameters are consistent with the drill bit encountering a high permeability zone and the contact zone of a magma chamber, respectively. Magma was intercepted three times between 2101-2104.4 m depth, which culminated in an increase in standpipe pressure followed by a decrease in weight on bit interpreted as representing the ascent of magma within the borehole. Circulation returned one hour after the last interception, carrying cuttings of glassy particles, felsite with granophyre and contaminant clasts from drilling, which were sampled as a time-series for the following 9 hours. The nature of glassy particles in this time-series varied through time, with a decrease in the proportion of vesicular clasts and a commensurate increase in dense glassy clasts, transitioning from initially colourless to brown glass. Componentry data show a sporadic decrease in felsite (from 34 wt. %), an increase in glassy particles during the first two hours (from 63 wt. % to 94 wt. %) and an increase in contaminant clasts towards the end of the cutting retrieval period. These temporal variations are probably related to the magma body architecture and interactions with the borehole. Transition from vesicular to dense clasts suggests a change in the degassing process that could be related to an early

Measurement and modelling of rainfall interception by tropical secondary forests in upland Eastern Madagascar

NASA Astrophysics Data System (ADS)

Prasad Ghimire, Chandra; van Meerveld, Ilja H. J.; Zwartendijk, Bob W.; Ravelona, Maafaka; Lahitiana, Jaona; Lubczynski, Maciek W.; Bruijnzeel, L. Adrian

2016-04-01

Secondary forests occupy a larger area than old-growth forest in many tropical regions but their hydrological functioning is still poorly understood. As part of a larger venture investigating the "trade-off" between the possibly strongly enhanced water use of vigorously regenerating secondary forest versus likely improved infiltration compared to degraded grassland (baseline situation) in Eastern Madagascar, this presentation reports on a comparison of measured and modelled canopy interception losses for a mature (ca. 20 years; basal area BA 35.5 m2 ha-1, LAI 3.39) and a young (5-7 years; BA 6.3 m2 ha-1, LAI 1.83) secondary forest. Measurements of gross rainfall (P), throughfall (TF) and stemflow (SF) were made in both forests over a one-year period (October 2014-September 2015). Interception losses (I) from the two forests were also simulated using the revised analytical model of Gash et al. (1995), representing a first for tropical secondary forest. Overall measured TF, SF and derived I in the mature secondary forest were 71.0%, 1.7% and 27.3% of incident P, respectively. Corresponding values for the young secondary forest were 75.8%, 6.2% and 18.0%. The high SF found for the latter forest reflects the strongly upward thrusting habit of the branches of the dominant species (Psiadia altissima) which favours funneling of incident P. The presently found I for the mature forest is similar to that reported for other tropical montane rainforests not affected by fog but that for the younger forest is higher than reported for similarly aged lowland forests. These findings can be explained by the prevailing low rainfall intensities and frequent occurrence of small rainfall events (~70% < 5 mm). The Gash model was able to reproduce measured cumulative I at both sites accurately and succeeded in capturing the variability in I associated with seasonal variability in rainfall characteristics, provided the TF-based value for wet-canopy evaporation rate was used instead of that

Overview of active methods for shielding spacecraft from energetic space radiation

NASA Technical Reports Server (NTRS)

Townsend, L. W.; Wilson, J. W. (Principal Investigator)

2001-01-01

During the 1960's and into the early 1970's, investigations were conducted related to the feasibility of using active radiation shielding methods, such as afforded by electromagnetic fields, as alternatives to passive, bulk material shielding to attenuate space radiations. These active concepts fall into four categories: (1) electrostatic fields; (2) plasma shields; (3) confined magnetic fields; and (4) unconfined magnetic fields. In nearly all of these investigations, consideration was given only to shielding against protons or electrons, or both. During the 1980's and 1990's there were additional studies related to proton shielding and some new studies regarding the efficacy of using active methods to shield from the high energy heavy ion (HZE particle) component of the galactic cosmic ray spectrum. In this overview, each concept category is reviewed and its applicability and limitations for the various types of space radiations are described. Recommendations for future research on this topic are made.

Cosmogenic beryllium-7 in soil, rainwater and selected plant species to evaluate the vegetal interception of atmospheric fine particulate matter.

PubMed

Saleh, Ibrahim H; Abdel-Halim, Aly A

2018-03-12

Beryllium-7 is a radionuclide produced in the upper atmosphere by cosmic-ray spallation with ions of carbon, oxygen and nitrogen. It is one of radionuclides that can be used to trace the fine particulate matter of 2.5-µm diameter (PM 2.5 ) and smaller. In this work, 7 Be was determined in leaves of 10 plant species collected from streets, parks and open land and in 5 consecutive rains over Alexandria, Egypt. 7 Be levels were also measured in soil covered by each type of plant as well as in the nearest uncovered soil to be reference values to determine its intercepted amount and consequently PM 2.5 . The lowest interception, 17.7 %, was by Ficus elastica L., while Ficus retusa L. intercepted about 45 %. Radiologically, the annual effective dose due to the usage of Thymelea hirsute plant leaves as a medicine and Nicotiana glauca Graham for smoking were 0.013 and 0.66 µSv, respectively. The observed levels in rainwater indicated that 7 Be decreased consecutively from 3.1 Bq kg -1 in the first rain to 0.71 Bq kg -1 in the last one during the 2016/2017 rain season. The wet deposition of 7 Be is less than 1 % of its total deposition on the ground.

Synchronizing Self and Object Movement: How Child and Adult Cyclists Intercept Moving Gaps in a Virtual Environment

ERIC Educational Resources Information Center

Chihak, Benjamin J.; Plumert, Jodie M.; Ziemer, Christine J.; Babu, Sabarish; Grechkin, Timofey; Cremer, James F.; Kearney, Joseph K.

2010-01-01

Two experiments examined how 10- and 12-year-old children and adults intercept moving gaps while bicycling in an immersive virtual environment. Participants rode an actual bicycle along a virtual roadway. At 12 test intersections, participants attempted to pass through a gap between 2 moving, car-sized blocks without stopping. The blocks were…

Naturally induced secondary radiation in interplanetary space: Preliminary analyses for gamma radiation and radioisotope production from thermal neutron activation

NASA Technical Reports Server (NTRS)

Plaza-Rosado, Heriberto

1991-01-01

Thermal neutron activation analyses were carried out for various space systems components to determine gamma radiation dose rates and food radiation contamination levels. The space systems components selected were those for which previous radiation studies existed. These include manned space vehicle radiation shielding, liquid hydrogen propellant tanks for a Mars mission, and a food supply used as space vehicle radiation shielding. The computational method used is based on the fast neutron distribution generated by the BRYNTRN and HZETRN transport codes for Galactic Cosmic Rays (GCR) at solar minimum conditions and intense solar flares in space systems components. The gamma dose rates for soft tissue are calculated for water and aluminum space vehicle slab shields considering volumetric source self-attenuation and exponential buildup factors. In the case of the lunar habitat with regolith shielding, a completely exposed spherical habitat was assumed for mathematical convenience and conservative calculations. Activation analysis of the food supply used as radiation shielding is presented for four selected nutrients: potassium, calcium, sodium, and phosphorus. Radioactive isotopes that could represent a health hazard if ingested are identified and their concentrations are identified. For nutrients soluble in water, it was found that all induced radioactivity was below the accepted maximum permissible concentrations.

Naturally induced secondary radiation in interplanetary space: Preliminary analyses for gamma radiation and radioisotope production from thermal neutron activation

NASA Astrophysics Data System (ADS)

Plaza-Rosado, Heriberto

1991-09-01

Thermal neutron activation analyses were carried out for various space systems components to determine gamma radiation dose rates and food radiation contamination levels. The space systems components selected were those for which previous radiation studies existed. These include manned space vehicle radiation shielding, liquid hydrogen propellant tanks for a Mars mission, and a food supply used as space vehicle radiation shielding. The computational method used is based on the fast neutron distribution generated by the BRYNTRN and HZETRN transport codes for Galactic Cosmic Rays (GCR) at solar minimum conditions and intense solar flares in space systems components. The gamma dose rates for soft tissue are calculated for water and aluminum space vehicle slab shields considering volumetric source self-attenuation and exponential buildup factors. In the case of the lunar habitat with regolith shielding, a completely exposed spherical habitat was assumed for mathematical convenience and conservative calculations. Activation analysis of the food supply used as radiation shielding is presented for four selected nutrients: potassium, calcium, sodium, and phosphorus. Radioactive isotopes that could represent a health hazard if ingested are identified and their concentrations are identified. For nutrients soluble in water, it was found that all induced radioactivity was below the accepted maximum permissible concentrations.

CONNECTION BETWEEN THE INCREASED FIBRINOGEN CONCENTRATION IN DOGS WITH RADIATION SICKNESS AND THE FIBRINOGENASE ACTIVITY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gordeeva, K.V.

1963-11-01

A study was made of the concentration of blood plasma fibrinogen in relation to the changes of fibrinogenase activity. Dogs with radiation sickness (severe, moderately severe, and mild) served as experimental animals. A rise of the blood plasma fibrinogen content was observed in dogs with severe and moderately severe radiation sickness. This phenomenon is especially pronounced at the height of radiation sickness. The activity of fibrinogenase in severe radiation sickness was considerably decreased at the initial period and at the height of the disease. The rise of fibrinogen content in severe and moderately severe radiation sickness should be regarded asmore » an adaptive reaction directed to control hemorrhages, not as the sequence of raduced fibrinogenase activity. (auth)« less

Radiation Hard Active Media R&D for CMS Hadron Endcap Calorimetry

NASA Astrophysics Data System (ADS)

Tiras, Emrah; CMS-HCAL Collaboration

2015-04-01

The High Luminosity LHC era imposes unprecedented radiation conditions on the CMS detectors targeting a factor of 5-10 higher than the LHC design luminosity. The CMS detectors will need to be upgraded in order to withstand these conditions yet maintain/improve the physics measurement capabilities. One of the upgrade options is reconstructing the CMS Endcap Calorimeters with a shashlik design electromagnetic section and replacing active media of the hadronic section with radiation-hard scintillation materials. In this context, we have studied various radiation-hard materials such as Polyethylene Naphthalate (PEN), Polyethylene Terephthalate (PET), HEM and quartz plates coated with various organic materials such as p-Terphenyl (pTp), Gallium doped Zinc Oxide (ZnO:Ga) and Anthracene. Here we discuss the related test beam activities, laboratory measurements and recent developments.

Test of Slope and Intercept Bias in College Admissions: A Response to Aguinis, Culpepper, and Pierce (2010)

ERIC Educational Resources Information Center

Mattern, Krista D.; Patterson, Brian F.

2013-01-01

Research on the predictive bias of cognitive tests has generally shown (a) no slope effects and (b) small intercept effects, typically favoring the minority group. Aguinis, Culpepper, and Pierce (2010) simulated data and demonstrated that statistical artifacts may have led to a lack of power to detect slope differences and an overestimate of the…

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.

The clinical outcome of skeletal anchorage in interceptive treatment (in growing patients) for class III malocclusion.

PubMed

Meyns, J; Brasil, D M; Mazzi-Chaves, J F; Politis, C; Jacobs, R

2018-04-27

A systematic review of the literature was performed regarding the clinical outcome (effectiveness) of bone anchorage devices in interceptive treatment for class III malocclusion. A search of Embase, PubMed and Web of Science databases yielded 285 papers. An additional two articles were retrieved through manual searching of the reference lists. After initial abstract selection, 32 potentially eligible articles were screened in detail, resulting in a final number of eight articles included in this review. Insufficient evidence was found regarding the effects of skeletal anchorage in interceptive class III treatment to support definitive conclusions on long-term skeletal effects and stability. In the short term, it seems that bone anchors can provide more skeletal effect with less dentoalveolar compensations and less unwanted vertical changes. This does not always exclude the use of a face mask. The use of miniscrews as skeletal anchorage device does not seem to provide more skeletal effect, although it could minimize the unwanted dental effects in the upper jaw. No information regarding the need for orthognathic surgery, orthodontic treatment time or patient compliance and complications was found in the selected articles. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Optimal impulsive time-fixed orbital rendezvous and interception with path constraints

NASA Technical Reports Server (NTRS)

Taur, D.-R.; Prussing, J. E.; Coverstone-Carroll, V.

1990-01-01

Minimum-fuel, impulsive, time-fixed solutions are obtained for the problem of orbital rendezvous and interception with interior path constraints. Transfers between coplanar circular orbits in an inverse-square gravitational field are considered, subject to a circular path constraint representing a minimum or maximum permissible orbital radius. Primer vector theory is extended to incorporate path constraints. The optimal number of impulses, their times and positions, and the presence of initial or final coasting arcs are determined. The existence of constraint boundary arcs and boundary points is investigated as well as the optimality of a class of singular arc solutions. To illustrate the complexities introduced by path constraints, an analysis is made of optimal rendezvous in field-free space subject to a minimum radius constraint.

Graphdiyne Nanoparticles with High Free Radical Scavenging Activity for Radiation Protection.

PubMed

Xie, Jiani; Wang, Ning; Dong, Xinghua; Wang, Chengyan; Du, Zhen; Mei, Linqiang; Yong, Yuan; Huang, Changshui; Li, Yuliang; Gu, Zhanjun; Zhao, Yuliang

2018-03-06

Numerous carbon networks materials comprised of benzene moieties, such as graphene and fullerene, have held great fascination for radioprotection because of their acknowledged good biocompatibility and strong free radical scavenging activity derived from their delocalized π-conjugated structure. Recently, graphdiyne, a new emerging carbon network material consisting of a unique chemical structure of benzene and acetylenic moieties, has gradually attracted attention in many research fields. Encouraged by its unique structure with strong conjugated π-system and highly reactive diacetylenic linkages, graphdiyne might have free radical activity and can thus be used as a radioprotector, which has not been investigated so far. Herein, for the first time, we synthesized bovine serum albumin (BSA)-modified graphdiyne nanoparticles (graphdiyne-BSA NPs) to evaluate their free radical scavenging ability and investigate their application for radioprotection both in cell and animal models. In vitro studies indicated that the graphdiyne-BSA NPs could effectively eliminate the free-radicals, decrease radiation-induced DNA damage in cells, and improve the viability of cells under ionizing radiation. In vivo experiments showed that the graphdiyne-BSA NPs could protect the bone marrow DNA of mice from radiation-induced damage and make the superoxide dismutase (SOD) and malondialdehyde (MDA) (two kinds of vital indicators of radiation-induced injury) recover back to normal levels. Furthermore, the good biocompatibility and negligible systemically toxicity responses of the graphdiyne-BSA NPs to mice were verified. All these results manifest the good biosafety and radioprotection activity of graphdiyne-BSA NPs to normal tissues. Therefore, our studies not only provide a new radiation protection platform based on graphdiyne for protecting normal tissues from radiation-caused injury but also provide a promising direction for the application of graphdiyne in the biomedicine field.

Examination and Mitigation of Electron Interception Processes in Dye-sensitized Solar Cells through Redox Shuttle and Photoelectrode Modification

NASA Astrophysics Data System (ADS)

Hoffeditz, William Lawrence

With the dual challenges of meeting global energy demand and mitigating anthropogenic climate change, significant effort is being applied to generating power from renewable sources. The dye-sensitized solar cell (DSC) is a photovoltaic technology capable of generating electricity from sunlight, but suffers losses in efficiency due to deleterious electron transfer processes. Controlling these processes is essential if DSCs are to continue to advance, and this dissertation focuses on isolation, interrogation, and mitigation of these processes via controllable inorganic redox/coordination chemistry and atomic layer deposition (ALD). The redox shuttle is often the subject of innovation in DSCs, the goal being to increase obtainable photovoltage without sacrificing photocurrent. A copper redox shuttle with a favorable (II/I) redox potential for DSC use and intriguing inner-sphere reorganization energy was investigated. The shuttle completely replaces its tetradentate coordinating ligand upon oxidation with multiple pyridine molecules. This new species displays markedly slower electron interception, necessitating fabrication of a new counter electrode in order for the shuttle to function. Upon reduction, the tetradentate ligand re-coordinates, creating a dual-species shuttle that outperforms either species as a Cu(II/I) shuttle in isolation. Photoelectrode modification is also the subject of innovation in DSCs. ALD is ideally suited for this type of innovation as it can coat high aspect surfaces with metal-oxide films of uniform thickness. The ALD post-treatment technique is described and used to deposit Al2O3 around a TiO2 adsorbed zinc-porphyrin dye. This technique is shown to prevent dye degradation from ambient air and/or light. Additionally, the architecture allows the study of dye-influenced electron interception processes. It was found that the presence of dye increased interception, which was attributed to dye-mediated electron hopping and/or superexchange

Radiation From Solar Activity | Radiation Protection | US EPA

EPA Pesticide Factsheets

2017-08-07

Solar flares, coronal mass ejections (CMEs) and geomagnetic storms from the sun can send extreme bursts of ionizing radiation and magnetic energy toward Earth. Some of this energy is in the form ionizing radiation and some of the energy is magnetic energy.

Purely numerical approach for analyzing flow to a well intercepting a vertical fracture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Narasimhan, T.N.; Palen, W.A.

1979-03-01

A numerical method, based on an Integral Finite Difference approach, is presented to investigate wells intercepting fractures in general and vertical fractures in particular. Such features as finite conductivity, wellbore storage, damage, and fracture deformability and its influence as permeability are easily handled. The advantage of the numerical approach is that it is based on fewer assumptions than analytic solutions and hence has greater generality. Illustrative examples are given to validate the method against known solutions. New results are presenteed to demonstrate the applicability of the method to problems not apparently considered in the literature so far.

WNT activation by lithium abrogates TP53 mutation associated radiation resistance in medulloblastoma.

PubMed

Zhukova, Nataliya; Ramaswamy, Vijay; Remke, Marc; Martin, Dianna C; Castelo-Branco, Pedro; Zhang, Cindy H; Fraser, Michael; Tse, Ken; Poon, Raymond; Shih, David J H; Baskin, Berivan; Ray, Peter N; Bouffet, Eric; Dirks, Peter; von Bueren, Andre O; Pfaff, Elke; Korshunov, Andrey; Jones, David T W; Northcott, Paul A; Kool, Marcel; Pugh, Trevor J; Pomeroy, Scott L; Cho, Yoon-Jae; Pietsch, Torsten; Gessi, Marco; Rutkowski, Stefan; Bognár, Laszlo; Cho, Byung-Kyu; Eberhart, Charles G; Conter, Cecile Faure; Fouladi, Maryam; French, Pim J; Grajkowska, Wieslawa A; Gupta, Nalin; Hauser, Peter; Jabado, Nada; Vasiljevic, Alexandre; Jung, Shin; Kim, Seung-Ki; Klekner, Almos; Kumabe, Toshihiro; Lach, Boleslaw; Leonard, Jeffrey R; Liau, Linda M; Massimi, Luca; Pollack, Ian F; Ra, Young Shin; Rubin, Joshua B; Van Meir, Erwin G; Wang, Kyu-Chang; Weiss, William A; Zitterbart, Karel; Bristow, Robert G; Alman, Benjamin; Hawkins, Cynthia E; Malkin, David; Clifford, Steven C; Pfister, Stefan M; Taylor, Michael D; Tabori, Uri

2014-12-24

TP53 mutations confer subgroup specific poor survival for children with medulloblastoma. We hypothesized that WNT activation which is associated with improved survival for such children abrogates TP53 related radioresistance and can be used to sensitize TP53 mutant tumors for radiation. We examined the subgroup-specific role of TP53 mutations in a cohort of 314 patients treated with radiation. TP53 wild-type or mutant human medulloblastoma cell-lines and normal neural stem cells were used to test radioresistance of TP53 mutations and the radiosensitizing effect of WNT activation on tumors and the developing brain. Children with WNT/TP53 mutant medulloblastoma had higher 5-year survival than those with SHH/TP53 mutant tumours (100% and 36.6%±8.7%, respectively (p<0.001)). Introduction of TP53 mutation into medulloblastoma cells induced radioresistance (survival fractions at 2Gy (SF2) of 89%±2% vs. 57.4%±1.8% (p<0.01)). In contrast, β-catenin mutation sensitized TP53 mutant cells to radiation (p<0.05). Lithium, an activator of the WNT pathway, sensitized TP53 mutant medulloblastoma to radiation (SF2 of 43.5%±1.5% in lithium treated cells vs. 56.6±3% (p<0.01)) accompanied by increased number of γH2AX foci. Normal neural stem cells were protected from lithium induced radiation damage (SF2 of 33%±8% for lithium treated cells vs. 27%±3% for untreated controls (p=0.05). Poor survival of patients with TP53 mutant medulloblastoma may be related to radiation resistance. Since constitutive activation of the WNT pathway by lithium sensitizes TP53 mutant medulloblastoma cells and protect normal neural stem cells from radiation, this oral drug may represent an attractive novel therapy for high-risk medulloblastomas.

Activating Photodynamic Therapy in vitro with Cerenkov Radiation Generated from Yttrium-90

PubMed Central

Hartl, Brad A.; Hirschberg, Henry; Marcu, Laura; Cherry, Simon R.

2017-01-01

The translation of photodynamic therapy (PDT) to the clinical setting has primarily been limited to easily accessible and/or superficial diseases, for which traditional light delivery can be performed noninvasively. Cerenkov radiation, as generated from medically relevant radionuclides, has been suggested as a means to deliver light to deeper tissues noninvasively to overcome this depth limitation. This article investigates the utility of Cerenkov radiation, as generated from the radionuclide yttrium-90, for activating the PDT process using clinically approved aminolevulinic acid at 1.0 mm and also the more efficient porphyrin-based photosensitizer mesotetraphenylporphine with two sulfonate groups on adjacent phenyl rings (TPPS2a) at 1.2 μM. Experiments were conducted with monolayer cultured glioma and breast tumor cell lines. Although aminolevulinic acid proved to be ineffective for generating a therapeutic effect at all but the highest activity levels, TPPS2a produced at least a 20% therapeutic effect at activities ranging from 6 to 60 μCi/well for the C6 glioma cell line. Importantly, these results demonstrate for the first time, to our knowledge, that Cerenkov radiation generated from a radionuclide can be used to activate PDT using clinically relevant photosensitizers. These results therefore provide evidence that it may be possible to generate a phototherapeutic effect in vivo using Cerenkov radiation and clinically relevant photosensitizers. PMID:27481495

Effects of gamma radiation on cork wastewater: Antioxidant activity and toxicity.

PubMed

Madureira, Joana; Pimenta, Andreia I; Popescu, Larisa; Besleaga, Alexandra; Dias, Maria Inês; Santos, Pedro M P; Melo, Rita; Ferreira, Isabel C F R; Cabo Verde, Sandra; Margaça, Fernanda M A

2017-02-01

A comprehensive assessment of the toxicity and antioxidant activity of cork boiling wastewater and the effects of gamma radiation on these parameters was performed. Antioxidant activity was evaluated using different methodologies as DPPH radical scavenging activity, reducing power and inhibition of β-carotene bleaching. The results have shown that gamma radiation can induce an increase on the antioxidant activity of cork boiling wastewater. Toxicity tests were performed to access the potential added value of the irradiated wastewaters and/or minimization of the impact for discharge in the environment. Two different methods for toxicity evaluation were followed, bacterial growth inhibition test and cytotoxicity assay, in order to predict the behavior of different cells (prokaryotic and eukaryotic) in the presence of cork wastewater. Non-treated cork boiling wastewater seemed to be non-toxic for prokaryotic cells (Pseudomonas fluorescens and Bacillus subtilis) but toxic for eukaryotic cells (A549 human cells and RAW264.7 mouse cells). The gamma radiation treatment at doses of 100 kGy appeared to increase the toxicity of cork compounds for all tested cells, which could be related to a toxic effect of radiolytic products of cork compounds in the wastewaters. Copyright © 2016 Elsevier Ltd. All rights reserved.

The IAEA’s activities on radiation protection in interventional cardiology

PubMed Central

Rehani, MM

2007-01-01

The International Atomic Energy Agency (IAEA) under its mandate of developing and applying standards of radiation safety has initiated a number of activities in recent years on radiation protection in interventional cardiology. These activities are implemented through four mechanisms, namely training, providing information through the website, research projects and assistance to Member States through Technical Cooperation (TC) projects. Major international initiatives have been taken in the area of training where more than half a dozen regional training courses have been conducted for cardiologists from over 50 countries. Additionally four national training events for over 300 medical and paramedical staff members involved in interventional procedures were held. The training material is freely available on CD from the IAEA. The newly established website provides information on radiation protection issues [1]. Two coordinated research projects have just been completed where peak skin doses to patients undergoing high dose interventional procedures were studied and factors to manage patient doses were identified. The technical cooperation projects involving protection in cardiac interventional procedures have 30 countries as participants. PMID:21614275

Degradation of Biochemical Activity in Soil Sterilized by Dry Heat and Gamma Radiation

NASA Technical Reports Server (NTRS)

Shih, K. L.; Souza, K. A.

1978-01-01

The effect of soil sterilization by dry heat (0.08% relative humidity), gamma radiation, or both on soil phosphatase, urease, and decarboxylase activity was studied. Soil sterilized by a long exposure to dry heat at relatively low temperatures (eight weeks at 100.5 C) retained higher activities than did soil exposed to a higher temperature (two weeks at 124.5 C), while all activity was destroyed by four days at 148.5 C. Sterilization with 7.5 Mrads destroyed less activity than did heat sterilization. The effect of several individually nonsterizing doses of heat radiation is described.

Comet Science Working Group report on the Halley Intercept Mission

NASA Technical Reports Server (NTRS)

1980-01-01

The Halley Intercept Mission is described and the scientific benefits expected from the program are defined. One characteristic of the mission is the optical navigation and resulting accurate delivery of the spacecraft to a desired point near the nucleus. This accuracy of delivery has two important implications: (1) high probability that the mass spectrometers and other in situ measurement devices will reach the cometary ionosphere and the zone of parent molecules next to the nucleus; (2) high probability that sunlit, high resolution images of Halley's nucleus will be obtained under proper lighting conditions. In addition an observatory phase is included during which high quality images of the tail and coma structure will be obtained at progressively higher spatial resolutions as the spacecraft approaches the comet. Complete measurements of the comet/solar wind interaction can be made around the time of encounter. Specific recommendations are made concerning project implementation and spacecraft requirements.

Active Beam Shaping System and Method Using Sequential Deformable Mirrors

NASA Technical Reports Server (NTRS)

Pueyo, Laurent A. (Inventor); Norman, Colin A. (Inventor)

2015-01-01

An active optical beam shaping system includes a first deformable mirror arranged to at least partially intercept an entrance beam of light and to provide a first reflected beam of light, a second deformable mirror arranged to at least partially intercept the first reflected beam of light from the first deformable mirror and to provide a second reflected beam of light, and a signal processing and control system configured to communicate with the first and second deformable mirrors. The first deformable mirror, the second deformable mirror and the signal processing and control system together provide a large amplitude light modulation range to provide an actively shaped optical beam.

The Potential Radiative Forcing of Global Land Use and Land Cover Change Activities

NASA Astrophysics Data System (ADS)

Ward, D. S.; Mahowald, N. M.; Kloster, S.

2014-12-01

Given the expected increase in pressure on land resources over the next century, there is a need to understand the total impacts of activities associated with land use and land cover change (LULCC). Here we quantify these impacts using the radiative forcing metric, including forcings from changes in long-lived greenhouse gases, tropospheric ozone, aerosol effects, and land surface albedo. We estimate radiative forcings from the different agents for historical LULCC and for six future projections using simulations from the National Center for Atmospheric Research Community Land Model and Community Atmosphere Models and additional offline analyses. When all forcing agents are considered together we show that 45% (+30%, -20%) of the present-day (2010) anthropogenic radiative forcing can be attributed to LULCC. Changes in the emission of non-CO2 greenhouse gases and aerosols from LULCC enhance the total LULCC radiative forcing by a factor of 2 to 3 with respect to the forcing from CO2 alone. In contrast, the non-CO2 forcings from fossil fuel burning are roughly neutral, due largely to the negative (cooling) impact of aerosols from these sources. We partition the global LULCC radiative forcing into three major sources: direct modification of land cover (e.g. deforestation), agricultural activities, and fire regime changes. Contributions from deforestation and agriculture are roughly equal in the present day, while changes to wildfire activity impose a small negative forcing globally. In 2100, deforestation activities comprise the majority of the LULCC radiative forcing for all projections except one (Representative Concentration Pathway (RCP) 4.5). This suggests that realistic scenarios of future forest area change are essential for projecting the contribution of LULCC to climate change. However, the commonly used RCP land cover change projections all include decreases in global deforestation rates over the next 85 years. To place an upper bound on the potential

Active magnetic radiation shielding system analysis and key technologies.

PubMed

Washburn, S A; Blattnig, S R; Singleterry, R C; Westover, S C

2015-01-01

Many active magnetic shielding designs have been proposed in order to reduce the radiation exposure received by astronauts on long duration, deep space missions. While these designs are promising, they pose significant engineering challenges. This work presents a survey of the major systems required for such unconfined magnetic field design, allowing the identification of key technologies for future development. Basic mass calculations are developed for each system and are used to determine the resulting galactic cosmic radiation exposure for a generic solenoid design, using a range of magnetic field strength and thickness values, allowing some of the basic characteristics of such a design to be observed. This study focuses on a solenoid shaped, active magnetic shield design; however, many of the principles discussed are applicable regardless of the exact design configuration, particularly the key technologies cited. Copyright © 2015 The Committee on Space Research (COSPAR). All rights reserved.

Calibration of the active radiation detector for Spacelab-One

NASA Technical Reports Server (NTRS)

1982-01-01

The flight models of the active radiation detector (ARD) for the ENV-01 environmental monitor were calibrated using gamma radiation. Measured sensitivities of the ion chambers were 6.1 + or - 0.3 micron rad per count for ARD S/N1, and 10.4 + or - 0.5 micron rad per count for ARD S/N2. Both were linear over the measured range 0.10 to 500 m/rad hour. The particle counters (proportional counters) were set to respond to approximately 85% of minimum ionizing particles of unit charge passing through them. These counters were also calibrated in the gamma field.

Lévy noise improves the electrical activity in a neuron under electromagnetic radiation.

PubMed

Wu, Juan; Xu, Yong; Ma, Jun

2017-01-01

As the fluctuations of the internal bioelectricity of nervous system is various and complex, the external electromagnetic radiation induced by magnet flux on membrane can be described by the non-Gaussian type distribution of Lévy noise. Thus, the electrical activities in an improved Hindmarsh-Rose model excited by the external electromagnetic radiation of Lévy noise are investigated and some interesting modes of the electrical activities are exhibited. The external electromagnetic radiation of Lévy noise leads to the mode transition of the electrical activities and spatial phase, such as from the rest state to the firing state, from the spiking state to the spiking state with more spikes, and from the spiking state to the bursting state. Then the time points of the firing state versus Lévy noise intensity are depicted. The increasing of Lévy noise intensity heightens the neuron firing. Also the stationary probability distribution functions of the membrane potential of the neuron induced by the external electromagnetic radiation of Lévy noise with different intensity, stability index and skewness papremeters are analyzed. Moreover, through the positive largest Lyapunov exponent, the parameter regions of chaotic electrical mode of the neuron induced by the external electromagnetic radiation of Lévy noise distribution are detected.

Lévy noise improves the electrical activity in a neuron under electromagnetic radiation

PubMed Central

Wu, Juan; Ma, Jun

2017-01-01

As the fluctuations of the internal bioelectricity of nervous system is various and complex, the external electromagnetic radiation induced by magnet flux on membrane can be described by the non-Gaussian type distribution of Lévy noise. Thus, the electrical activities in an improved Hindmarsh-Rose model excited by the external electromagnetic radiation of Lévy noise are investigated and some interesting modes of the electrical activities are exhibited. The external electromagnetic radiation of Lévy noise leads to the mode transition of the electrical activities and spatial phase, such as from the rest state to the firing state, from the spiking state to the spiking state with more spikes, and from the spiking state to the bursting state. Then the time points of the firing state versus Lévy noise intensity are depicted. The increasing of Lévy noise intensity heightens the neuron firing. Also the stationary probability distribution functions of the membrane potential of the neuron induced by the external electromagnetic radiation of Lévy noise with different intensity, stability index and skewness papremeters are analyzed. Moreover, through the positive largest Lyapunov exponent, the parameter regions of chaotic electrical mode of the neuron induced by the external electromagnetic radiation of Lévy noise distribution are detected. PMID:28358824

Effects of pathogen reduction systems on platelet microRNAs, mRNAs, activation, and function

PubMed Central

Osman, Abdimajid; Hitzler, Walter E.; Meyer, Claudius U.; Landry, Patricia; Corduan, Aurélie; Laffont, Benoit; Boilard, Eric; Hellstern, Peter; Vamvakas, Eleftherios C.

2015-01-01

Pathogen reduction (PR) systems for platelets, based on chemically induced cross-linking and inactivation of nucleic acids, potentially prevent transfusion transmission of infectious agents, but can increase clinically significant bleeding in some clinical studies. Here, we documented the effects of PR systems on microRNA and mRNA levels of platelets stored in the blood bank, and assessed their impact on platelet activation and function. Unlike platelets subjected to gamma irradiation or stored in additive solution, platelets treated with Intercept (amotosalen + ultraviolet-A [UVA] light) exhibited significantly reduced levels of 6 of the 11 microRNAs, and 2 of the 3 anti-apoptotic mRNAs (Bcl-xl and Clusterin) that we monitored, compared with platelets stored in plasma. Mirasol (riboflavin + UVB light) treatment of platelets did not produce these effects. PR neither affected platelet microRNA synthesis or function nor induced cross-linking of microRNA-sized endogenous platelet RNA species. However, the reduction in the platelet microRNA levels induced by Intercept correlated with the platelet activation (p < 0.05) and an impaired platelet aggregation response to ADP (p < 0.05). These results suggest that Intercept treatment may induce platelet activation, resulting in the release of microRNAs and mRNAs from platelets. The clinical implications of this reduction in platelet nucleic acids secondary to Intercept remain to be established. PMID:24749844

Field Evaluation of Model II of the Computer-Based, Individual Trainer for the Radar Intercept Officer

DTIC Science & Technology

1974-07-01

of an (almost) completely automated CAI capability for teaching skills for the Radar Intercept Officer’s (RIO’s) job. Contributions made by this...expected) from such features. At present, the utility of developing CAI materials for teaching the utiliza- tion of the AWG-9 system for maintaining...this complexity is necessary even though the trainer -as designed to teach only basic skills used in this performance. Therefore, chc details of the

Intercepting beats in predesignated target zones.

PubMed

Craig, Cathy; Pepping, Gert-Jan; Grealy, Madeleine

2005-09-01

Moving to a rhythm necessitates precise timing between the movement of the chosen limb and the timing imposed by the beats. However, the temporal information specifying the moment when a beat will sound (the moment onto which one must synchronise one's movement) is not continuously provided by the acoustic array. Because of this informational void, the actors need some form of prospective information that will allow them to act sufficiently ahead of time in order to get their hand in the right place at the right time. In this acoustic interception study, where participants were asked to move between two targets in such a way that they arrived and stopped in the target zone at the same time as a beat sounded, we tested a model derived from tau-coupling theory (Lee DN (1998) Ecol Psychol 10:221-250). This model attempts to explain the form of a potential timing guide that specifies the duration of the inter-beat intervals and also describes how this informational guide can be used in the timing and guidance of movements. The results of our first experiment show that, for inter-beat intervals of less than 3 s, a large proportion of the movement (over 70%) can be explained by the proposed model. However, a second experiment, which augments the time between beats so that it surpasses 3 s, shows a marked decline in the percentage of information/movement coupling. A close analysis of the movement kinematics indicates a lack of control and anticipation in the participants' movements. The implications of these findings, in light of other research studies, are discussed.

Opportunities and challenges to conserve water on the landscape in snow-dominated forests: The quest for the radiative minima and more...

NASA Astrophysics Data System (ADS)

Link, T. E.; Kumar, M.; Pomeroy, J. W.; Seyednasrollah, B.; Ellis, C. R.; Lawler, R.; Essery, R.

2012-12-01

In mountainous, forested environments, vegetation exerts a strong control on snowcover dynamics that affect ecohydrological processes, streamflow regimes, and riparian health. Snowcover deposition and ablation patterns in forests are controlled by a complex combination of canopy interception processes coupled with radiative and turbulent heat flux patterns related to topographic and canopy cover variations. In seasonal snow environments, snowcover ablation dynamics in forests are dominated by net radiation. Recent research indicates that in small canopy gaps a net radiation minima relative to both open and forested environments can occur, but depends strongly on solar angle, gap size, slope, canopy height and stem density. The optimal gap size to minimize radiation to snow was estimated to have a diameter between 1 and 2 times the surrounding vegetation height. Physically-based snowmelt simulations indicate that gaps may increase SWE and desynchronize snowmelt by approximately 3 weeks between north and south facing slopes, relative to undisturbed forests. On east and west facing slopes, small gaps cause melt to be slightly delayed relative to intact forests, and have a minimal effect on melt synchronicity between slopes. Recent research focused on canopy thinning also indicates that a net radiation minima occurs in canopies of intermediate densities. Physically-based radiative transfer simulations using a discrete tree-based model indicate that in mid-latitude level forests, the annually-integrated radiative minima occurs at a tree spacing of 2.65 relative to the canopy height. The radiative minima was found to occur in denser forests on south-facing slopes and sparser forests on north-facing slopes. The radiative minimums in thinned forests are controlled by solar angle, crown geometry and density, tree spacing, slope, and aspect. These results indicate that both gap and homogeneous forest thinning may be used to reduce snowmelt rates or alter melt synchronicity

Active charge trapping control in dielectrics under ionizing radiation

NASA Astrophysics Data System (ADS)

Dominguez-Pumar, M.; Bheesayagari, C.; Gorreta, S.; Pons-Nin, J.

2017-12-01

Charge trapping is is a design and reliability factor in plasma sensors. Examples can be found in microchannel plate detectors in plasma analyzers, where multiple layers have been devised to ensure filled trapped electrons for enhanced secondary emission [1]. Charge trap mapping is used to recover distortion in telescope CCDs [2]. Specific technologies are designed to mitigate the effect of ionizing radiation in monolithic Active Pixel Sensors [3]. We report in this paper a control loop designed to control charge in Metal-Oxide-Semiconductor capacitors. We find that the net trapped charge in the device can be set within some limits to arbitrary values that can be changed with time. The control loop periodically senses the net trapped charge by detecting shifts in the capacitance vs voltage characteristic, and generates adequate waveform sequences to keep the trapped charge at the desired level [4]. The waveforms continuously applied have been chosen to provide different levels of charge injection into the dielectric. The control generates the adequate average charge injection to reach and maintain the desired level of trapped charge, compensating external disturbances. We also report that this control can compensate charge generated by ionizing radiation. Experiments will be shown in which this compensation is obtained with X-rays and gamma radiation. The presented results open the possibility of applying active compensation techniques for the first time in a wide number of devices such as radiation sensors, MOS transistors and other devices. The continuous drive towards integration may allow the implementation of this type of controls in devices needing to reject external disturbances, or needing to optimize their response to radiation or ion fluxes. References: [1] patent US 2009/0212680 A1. [2] A&A 534, A20 (2011). [3] Hemperek, Nucl. Instr. and Meth. in Phys. Res. Sect. A.796, pp 8-12, 2015. [4] Dominguez, IEEE Trans. Ind. Electr, 64 (4), 3023-3029, 2017.

Biological activities caused by far-infrared radiation

NASA Astrophysics Data System (ADS)

Inoué, Shojiro; Kabaya, Morihiro

1989-09-01

Contrary to previous presumption, accumulated evidence indicates that far-infrared rays are biologically active. A small ceramic disk that emist far-infrared rays (4 16 μm) has commonly been applied to a local spot or a whole part of the body for exposure. Pioneering attempts to experimentally analyze an effect of acute and chronic radiation of far-infrared rays on living organisms have detected a growth-promoting effect in growing rats, a sleep-modulatory effect in freely behaving rats and an insomiac patient, and a blood circulation-enhancing effect in human skin. Question-paires to 542 users of far-infrared radiator disks embedded in bedelothes revealed that the majority of the users subjectively evaluated an improvement of their health. These effects on living organisms appear to be non-specifically triggered by an exposure to far-infrared rays, which eventually induce an increase in temperature of the body tissues or, more basically, an elevated motility of body fluids due to decrease in size of water clusters.

Pathogen exploitation of an abscisic acid- and jasmonate-inducible MAPK phosphatase and its interception by Arabidopsis immunity.

PubMed

Mine, Akira; Berens, Matthias L; Nobori, Tatsuya; Anver, Shajahan; Fukumoto, Kaori; Winkelmüller, Thomas M; Takeda, Atsushi; Becker, Dieter; Tsuda, Kenichi

2017-07-11

Phytopathogens promote virulence by, for example, exploiting signaling pathways mediated by phytohormones such as abscisic acid (ABA) and jasmonate (JA). Some plants can counteract pathogen virulence by invoking a potent form of immunity called effector-triggered immunity (ETI). Here, we report that ABA and JA mediate inactivation of the immune-associated MAP kinases (MAPKs), MPK3 and MPK6, in Arabidopsis thaliana ABA induced expression of genes encoding the protein phosphatases 2C (PP2Cs), HAI1 , HAI2 , and HAI3 through ABF/AREB transcription factors. These three HAI PP2Cs interacted with MPK3 and MPK6 and were required for ABA-mediated MPK3/MPK6 inactivation and immune suppression. The bacterial pathogen Pseudomonas syringae pv. tomato ( Pto ) DC3000 activates ABA signaling and produces a JA-mimicking phytotoxin, coronatine (COR), that promotes virulence. We found that Pto DC3000 induces HAI1 through COR-mediated activation of MYC2, a master transcription factor in JA signaling. HAI1 dephosphorylated MPK3 and MPK6 in vitro and was necessary for COR-mediated suppression of MPK3/MPK6 activation and immunity. Intriguingly, upon ETI activation, A. thaliana plants overcame the HAI1-dependent virulence of COR by blocking JA signaling. Finally, we showed conservation of induction of HAI PP2Cs by ABA and JA in other Brassicaceae species. Taken together, these results suggest that ABA and JA signaling pathways, which are hijacked by the bacterial pathogen, converge on the HAI PP2Cs that suppress activation of the immune-associated MAPKs. Also, our data unveil interception of JA-signaling activation as a host counterstrategy against the bacterial suppression of MAPKs during ETI.

Survey of the learning activities of Australasian radiation oncology specialist trainees.

PubMed

Holt, T; Bydder, S; Bloomfield, L

2008-12-01

Trainee radiation oncologists must master a substantial body of skills and knowledge to become competent specialists. The resources available to support this are limited. We surveyed the 90 registrars enrolled in the Royal Australian and New Zealand College of Surgeons (RANZCR) radiation oncology training programme to obtain a range of information about their learning activities (with a significant focus on part 1 teaching). Responses were received from 59 registrars (66% of those eligible). Trainees reported spending a median 2.5 h per week (range 0-10 h) in formal teaching activities. With regard to part 1 exam preparation, 83% reported having had physics teaching--the median quality was 5/7; 88% had radiobiology teaching--the median quality was 4/7; 52% had anatomy teaching--the median quality was 3/7. Registrars training within the RANZCR radiation oncologists training programme perceive their own clinical learning environment as generally good; however' 50% of respondents felt that more teaching was needed for part 1 subjects. This compared with only 19% of respondents who felt that more teaching was required for part 2 exam preparation. Innovative solutions, such as centralized web-based teaching, may help to address weaknesses in part 1 teaching. With increasing demands on radiation oncologists and trainees it will be important to monitor learning environments.

Relationship Between Canopy Dynamics and Stem Volume Production of Four Species Receiving Irrigation and Fertilization

Treesearch

Chrisopher B Allen; Rodney E. Will; Terry Sarigumba; Marshall A. Jacobson; Richard F. Daniels; Stephen A. Kennerly

2004-01-01

We measured the effects of irrigation and varying levels of fertilization on intercepted photosynthetically active radiation (IPAR), projected leaf area index (LAI), and foliar nitrogen concentration ([N]) in order to determine the relationship between resource availability, canopy size, and stem-volume growth. Stands of sycamore (Platanus occidentalis...

[Effect of low-intensity 900 MHz frequency electromagnetic radiation on rat liver and blood serum enzyme activities].

PubMed

Nersesova, L S; Petrosian, M S; Gazariants, M G; Mkrtchian, Z S; Meliksetian, G O; Pogosian, L G; Akopian, Zh I

2014-01-01

The comparative analysis of the rat liver and blood serum creatine kinase, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and purine nucleoside phosphorylase post-radiation activity levels after a total two-hour long single and fractional exposure of the animals to low-intensity 900 MHz frequency electromagnetic field showed that the most sensitive enzymes to the both schedules of radiation are the liver creatine kinase, as well as the blood serum creatine kinase and alkaline phosphatase. According to the comparative analysis of the dynamics of changes in the activity level of the liver and blood serum creatine kinase, alanine aminotransferase, aspartate aminotransferase and purine nucleoside phosphorylase, both single and fractional radiation schedules do not affect the permeability of a hepatocyte cell membrane, but rather cause changes in their energetic metabolism. The correlation analysis of the post-radiation activity level changes of the investigated enzymes did not reveal a clear relationship between them. The dynamics of post-radiation changes in the activity of investigated enzyme levels following a single and short-term fractional schedules of radiation did not differ essentially.

Optical design of a high radiative flux solar furnace for Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riveros-Rosas, D.; Perez-Rabago, C.A.; Arancibia-Bulnes, C.A.

2010-05-15

In the present work, the optical design of a new high radiative flux solar furnace is described. Several optical configurations for the concentrator of the system have been considered. Ray tracing simulations were carried out in order to determine the concentrated radiative flux distributions in the focal zone of the system, for comparing the different proposals. The best configuration was chosen in terms of maximum peak concentration, but also in terms of economical and other practical considerations. It consists of an arrangement of 409 first surface spherical facets with hexagonal shape, mounted on a spherical frame. The individual orientation ofmore » the facets is corrected in order to compensate for aberrations. The design considers an intercepted power of 30 kW and a target peak concentration above 10,000 suns. The effect of optical errors was also considered in the simulations. (author)« less

Radiative transfer in shrub savanna sites in Niger: Preliminary results from HAPEX-Sahel. Part 1: Modelling surface reflectance using a geometric-optical approach

NASA Technical Reports Server (NTRS)

Franklin, Janet; Duncan, Jeff; Huete, Alfredo R.; vanLeeuwen, W. J. D.; Li, Xiaowen; Begue, Agnes

1994-01-01

To use optical remote sensing to monitor land surface-climate interactions over large areas, algorithms must be developed to relate multispectral measurements to key variables controlling the exchange of matter (water, carbon dioxide) and energy between the land surface and the atmosphere. The proportion of the ground covered by vegetation and the interception of photosynthetically active radiation (PAR) by vegetation are examples of two variables related to evapotranspiration and primary production, respectively. An areal-proportion model of the multispectral reflectance of shrub savanna, composed of scattered shrubs with a grass, forb or soil understory, predicted the reflectance of two 0.5 km(exp 2) sites as the area-weighted average of the shrub and understory or 'background' reflectances. Although the shaded crown and shaded background have darker reflectances, ignoring them in the area-weighted model is not serious when shrub cover is low and solar zenith angle is small. A submodel predicted the reflectance of the shrub crown as a function of the foliage reflectance and amount of plant material within the crown, and the background reflectance scattered or transmitted through canopy gaps (referred to as a soil-plant 'spectral interaction' term). One may be able to combine these two models to estimate both the fraction of vegetation cover and interception of PAR by green vegetation in a shrub savanna.

Effects of yak-activated protein on hematopoiesis and related cytokines in radiation-induced injury in mice.

PubMed

Duan, Yabin; Yao, Xingchen; Zhu, Junbo; Li, Yongping; Zhang, Juanling; Zhou, Xuejiao; Qiao, Yijie; Yang, Meng; Li, Xiangyang

2017-12-01

The aim of the present study was to investigate the protective effects of yak-activated protein on hematopoiesis and cytokine function in radiation-induced injury in mice. A total of 180 Kunming mice were randomly divided into three groups (A, B and C). Of these, 60 were randomly divided into a normal control group, a radiation model group, a positive control group and 3 yak-activated protein groups (high, medium and low dose groups; 10, 5 and 2.5 mg/kg, respectively). The other 120 mice were used for the subsequent experiments on days 7 and 14 following radiation. Yak-activated protein was administered orally to mice in the treatment groups and an equal volume of saline was administered orally to mice in the normal control and radiation model groups for 14 days. The positive control group received amifostine (150 mg/kg) via intraperitoneal injection. With the exception of the control group, the groups of mice received a 5 Gy quantity of X-radiation evenly over their whole body once. Changes in the peripheral hemogram, thymus and spleen indices, DNA content in the bone marrow, interleukin (IL)-2 and IL-6 levels, and the expression levels of B cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax) following irradiation were assessed. The low dose of yak-activated protein significantly increased Spleen indices in mice 14 days after irradiation and the high and middle dose of yak-activated protein significantly increased Thymus indices in mice 14 days after irradiation (P<0.05) compared with the control group. In addition, hemogram results increased gradually in the low-yak-activated protein dose group and were significantly higher 7 days after irradiation compared with the radiation model group (P<0.05). The DNA content in the bone marrow was markedly increased in the yak-activated protein groups, and increased significantly in the low dose group at 7 days post-irradiation compared with the radiation model group (P<0.05). The IL-2 content was significantly

Effects of yak-activated protein on hematopoiesis and related cytokines in radiation-induced injury in mice

PubMed Central

Duan, Yabin; Yao, Xingchen; Zhu, Junbo; Li, Yongping; Zhang, Juanling; Zhou, Xuejiao; Qiao, Yijie; Yang, Meng; Li, Xiangyang

2017-01-01

The aim of the present study was to investigate the protective effects of yak-activated protein on hematopoiesis and cytokine function in radiation-induced injury in mice. A total of 180 Kunming mice were randomly divided into three groups (A, B and C). Of these, 60 were randomly divided into a normal control group, a radiation model group, a positive control group and 3 yak-activated protein groups (high, medium and low dose groups; 10, 5 and 2.5 mg/kg, respectively). The other 120 mice were used for the subsequent experiments on days 7 and 14 following radiation. Yak-activated protein was administered orally to mice in the treatment groups and an equal volume of saline was administered orally to mice in the normal control and radiation model groups for 14 days. The positive control group received amifostine (150 mg/kg) via intraperitoneal injection. With the exception of the control group, the groups of mice received a 5 Gy quantity of X-radiation evenly over their whole body once. Changes in the peripheral hemogram, thymus and spleen indices, DNA content in the bone marrow, interleukin (IL)-2 and IL-6 levels, and the expression levels of B cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax) following irradiation were assessed. The low dose of yak-activated protein significantly increased Spleen indices in mice 14 days after irradiation and the high and middle dose of yak-activated protein significantly increased Thymus indices in mice 14 days after irradiation (P<0.05) compared with the control group. In addition, hemogram results increased gradually in the low-yak-activated protein dose group and were significantly higher 7 days after irradiation compared with the radiation model group (P<0.05). The DNA content in the bone marrow was markedly increased in the yak-activated protein groups, and increased significantly in the low dose group at 7 days post-irradiation compared with the radiation model group (P<0.05). The IL-2 content was significantly

Missile sizing for ascent-phase intercept

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hull, D.G.; Salguero, D.E.

1994-11-01

A computer code has been developed to determine the size of a ground-launched, multistage missile which can intercept a theater ballistic missile before it leaves the atmosphere. Typical final conditions for the inteceptor are 450 km range, 60 km altitude, and 80 sec flight time. Given the payload mass (35 kg), which includes a kinetic kill vehicle, and achievable values for the stage mass fractions (0.85), the stage specific impulses (290 sec), and the vehicle density (60 lb/ft{sup 3}), the launch mass is minimized with respect to the stage payload mass ratios, the stage burn times, and the missile anglemore » of attack history subject to limits on the angle of attack (10 deg), the dynamic pressure (60,000 psf), and the maneuver load (200,000 psf deg). For a conical body, the minimum launch mass is approximately 1900 kg. The missile has three stages, and the payload coasts for 57 sec. A trade study has been performed by varying the flight time, the range, and the dynamic pressure Emits. With the results of a sizing study for a 70 lb payload and q{sub max} = 35,000 psf, a more detailed design has been carried out to determine heat shield mass, tabular aerodynamics, and altitude dependent thrust. The resulting missile has approximately 100 km less range than the sizing program predicted primarily because of the additional mass required for heat protection. On the other hand, launching the same missile from an aircraft increases its range by approximately 100 km. Sizing the interceptor for air launch with the same final conditions as the ground-launched missile reduces its launch mass to approximately 1000 kg.« less

Technique for Configuring an Actively Cooled Thermal Shield in a Flight System

NASA Technical Reports Server (NTRS)

Barkfknecht, Peter; Mustafi, Shuvo

2011-01-01

Broad area cooling shields are a mass-efficient alternative to conductively cooled thermal radiation shielding. The shield would actively intercept a large portion of incident thermal radiation and transport the heat away using cryogenic helium gas. The design concept consists of a conductive and conformable surface that maximizes heat transfer and formability. Broad Area Cooled (BAC) shields could potentially provide considerable mass savings for spaceflight applications by eliminating the need for a rigid thermal radiation shield for cryogen tanks. The BAC consists of a network of capillary tubes that are thermally connected to a conductive shield material. Chilled helium gas is circulated through the network and transports unwanted heat away from the cryogen tanks. The cryogenic helium gas is pumped and chilled simultaneously using a specialized pulse-tube cryocooler, which further improves the mass efficiency of the system. By reducing the thermal environment temperature from 300 to 100 K, the radiative heat load on a cryogen tank could be reduced by an order of magnitude. For a cryogenic liquid propellant scenario of oxygen and hydrogen, the boiloff of hydrogen would be significantly reduced and completely eliminated for oxygen. A major challenge in implementing this technology on large tanks is that the BAC system must be easily scalable from lab demonstrations to full-scale missions. Also, the BAC shield must be conformable to complex shapes like spheres without losing the ability to maintain constant temperature throughout. The initial design maximizes thermal conductivity between the capillary tube and the conductive radiation shielding by using thin, corrugated aluminum foil with the tube running transverse to the folds. This configuration has the added benefit of enabling the foil to stretch and contract longitudinally. This allows the BAC to conform to the complex curvature of a cryogen tank, which is key to its success. To demonstrate a BAC shield

Radiation activated CHK1/MEPE pathway may contribute to microgravity-induced bone density loss

NASA Astrophysics Data System (ADS)

Zhang, Xiangming; Wang, Ping; Wang, Ya

2015-11-01

Bone density loss in astronauts on long-term space missions is a chief medical concern. Microgravity in space is the major cause of bone density loss (osteopenia), and it is believed that high linear energy transfer (LET) radiation in space exacerbates microgravity-induced bone density loss; however, the mechanism remains unclear. It is known that acidic serine- and aspartate-rich motif (ASARM) as a small peptide released by matrix extracellular phosphoglycoprotein (MEPE) promotes osteopenia. We previously discovered that MEPE interacted with checkpoint kinase 1 (CHK1) to protect CHK1 from ionizing radiation promoted degradation. In this study, we addressed whether the CHK1-MEPE pathway activated by radiation contributes to the effects of microgravity on bone density loss. We examined the CHK1, MEPE and secreted MEPE/ASARM levels in irradiated (1 Gy of X-ray) and rotated cultured human osteoblast cells. The results showed that radiation activated CHK1, decreased the levels of CHK1 and MEPE in human osteoblast cells and increased the release of MEPE/ASARM. These results suggest that the radiation-activated CHK1/MEPE pathway exacerbates the effects of microgravity on bone density loss, which may provide a novel targeting factor/pathway for a future countermeasure design that could contribute to reducing osteopenia in astronauts.

The effect of cactus spines on light interception and Photosystem II for three sympatric species of Opuntia from the Mojave Desert.

PubMed

Loik, Michael E

2008-09-01

Cactus spines reduce herbivory, direct water toward roots and reduce the impacts of high- and low-temperature extremes. Yet, shading of stems by spines reduces incident photosynthetic photon flux density (PFD), photosynthesis and growth. This study compared spinescence, PFD interception, stem temperature, Photosystem II (PSII) photochemistry and xanthophyll pigment composition for three species of cacti from the Mojave Desert, CA. The species vary in spinescence: Opuntia basilaris, which has no central or radial spines; Opuntia erinacea, which is densely covered with spines; and Opuntia phaeacantha, which has an intermediate coverage of spines. The role of spines was tested by removing spines from stems of O. erinacea. PFD interception was similar for both O. basilaris and O. phaeacantha, and about three times that for densely spined O. erinacea; removal of spines increased incident PFD three-fold. There were no effects of spines on stem temperatures. Steady-state light-response curves of chlorophyll a fluorescence from PSII indicated that PhiPSII, photochemical quenching (qP) and electron flux within PSII were lower, and non-photochemical quenching was higher, for O. erinacea in comparison to the other two species with less spines. After 2 months, qP was higher and electron flux lower, and xanthophyll pigment pool size was higher, for stems from which spines had been removed compared with intact stems. These three species allocate different amounts of biomass to spines, resulting in species-specific PFD interception, PSII photochemistry and xanthophyll pigment pool size, which may help maintain rates of photosynthesis during the hot, dry Mojave Desert summer.

Development of Antioxidant COX-2 Inhibitors as Radioprotective Agents for Radiation Therapy—A Hypothesis-Driven Review

PubMed Central

Laube, Markus; Kniess, Torsten; Pietzsch, Jens

2016-01-01

Radiation therapy (RT) evolved to be a primary treatment modality for cancer patients. Unfortunately, the cure or relief of symptoms is still accompanied by radiation-induced side effects with severe acute and late pathophysiological consequences. Inhibitors of cyclooxygenase-2 (COX-2) are potentially useful in this regard because radioprotection of normal tissue and/or radiosensitizing effects on tumor tissue have been described for several compounds of this structurally diverse class. This review aims to substantiate the hypothesis that antioxidant COX-2 inhibitors are promising radioprotectants because of intercepting radiation-induced oxidative stress and inflammation in normal tissue, especially the vascular system. For this, literature reporting on COX inhibitors exerting radioprotective and/or radiosensitizing action as well as on antioxidant COX inhibitors will be reviewed comprehensively with the aim to find cross-points of both and, by that, stimulate further research in the field of radioprotective agents. PMID:27104573

Differential contributions to the interception of occluded ballistic trajectories by the temporoparietal junction, area hMT/V5+, and the intraparietal cortex.

PubMed

Delle Monache, Sergio; Lacquaniti, Francesco; Bosco, Gianfranco

2017-09-01

The ability to catch objects when transiently occluded from view suggests their motion can be extrapolated. Intraparietal cortex (IPS) plays a major role in this process along with other brain structures, depending on the task. For example, interception of objects under Earth's gravity effects may depend on time-to-contact predictions derived from integration of visual signals processed by hMT/V5+ with a priori knowledge of gravity residing in the temporoparietal junction (TPJ). To investigate this issue further, we disrupted TPJ, hMT/V5+, and IPS activities with transcranial magnetic stimulation (TMS) while subjects intercepted computer-simulated projectile trajectories perturbed randomly with either hypo- or hypergravity effects. In experiment 1 , trajectories were occluded either 750 or 1,250 ms before landing. Three subject groups underwent triple-pulse TMS (tpTMS, 3 pulses at 10 Hz) on one target area (TPJ | hMT/V5+ | IPS) and on the vertex (control site), timed at either trajectory perturbation or occlusion. In experiment 2 , trajectories were entirely visible and participants received tpTMS on TPJ and hMT/V5+ with same timing as experiment 1 tpTMS of TPJ, hMT/V5+, and IPS affected differently the interceptive timing. TPJ stimulation affected preferentially responses to 1-g motion, hMT/V5+ all response types, and IPS stimulation induced opposite effects on 0-g and 2-g responses, being ineffective on 1-g responses. Only IPS stimulation was effective when applied after target disappearance, implying this area might elaborate memory representations of occluded target motion. Results are compatible with the idea that IPS, TPJ, and hMT/V5+ contribute to distinct aspects of visual motion extrapolation, perhaps through parallel processing. NEW & NOTEWORTHY Visual extrapolation represents a potential neural solution to afford motor interactions with the environment in the face of missing information. We investigated relative contributions by temporoparietal junction

Quantification of the effects of architectural traits on dry mass production and light interception of tomato canopy under different temperature regimes using a dynamic functional–structural plant model

PubMed Central

Chen, Tsu-Wei; Nguyen, Thi My Nguyet; Kahlen, Katrin; Stützel, Hartmut

2014-01-01

There is increasing interest in evaluating the environmental effects on crop architectural traits and yield improvement. However, crop models describing the dynamic changes in canopy structure with environmental conditions and the complex interactions between canopy structure, light interception, and dry mass production are only gradually emerging. Using tomato (Solanum lycopersicum L.) as a model crop, a dynamic functional–structural plant model (FSPM) was constructed, parameterized, and evaluated to analyse the effects of temperature on architectural traits, which strongly influence canopy light interception and shoot dry mass. The FSPM predicted the organ growth, organ size, and shoot dry mass over time with high accuracy (>85%). Analyses of this FSPM showed that, in comparison with the reference canopy, shoot dry mass may be affected by leaf angle by as much as 20%, leaf curvature by up to 7%, the leaf length:width ratio by up to 5%, internode length by up to 9%, and curvature ratios and leaf arrangement by up to 6%. Tomato canopies at low temperature had higher canopy density and were more clumped due to higher leaf area and shorter internodes. Interestingly, dry mass production and light interception of the clumped canopy were more sensitive to changes in architectural traits. The complex interactions between architectural traits, canopy light interception, dry mass production, and environmental conditions can be studied by the dynamic FSPM, which may serve as a tool for designing a canopy structure which is ‘ideal’ in a given environment. PMID:25183746

Mathematical Model for the Contribution of Individual Organs to Non-Zero Y-Intercepts in Single and Multi-Compartment Linear Models of Whole-Body Energy Expenditure

PubMed Central

Kaiyala, Karl J.

2014-01-01

Mathematical models for the dependence of energy expenditure (EE) on body mass and composition are essential tools in metabolic phenotyping. EE scales over broad ranges of body mass as a non-linear allometric function. When considered within restricted ranges of body mass, however, allometric EE curves exhibit ‘local linearity.’ Indeed, modern EE analysis makes extensive use of linear models. Such models typically involve one or two body mass compartments (e.g., fat free mass and fat mass). Importantly, linear EE models typically involve a non-zero (usually positive) y-intercept term of uncertain origin, a recurring theme in discussions of EE analysis and a source of confounding in traditional ratio-based EE normalization. Emerging linear model approaches quantify whole-body resting EE (REE) in terms of individual organ masses (e.g., liver, kidneys, heart, brain). Proponents of individual organ REE modeling hypothesize that multi-organ linear models may eliminate non-zero y-intercepts. This could have advantages in adjusting REE for body mass and composition. Studies reveal that individual organ REE is an allometric function of total body mass. I exploit first-order Taylor linearization of individual organ REEs to model the manner in which individual organs contribute to whole-body REE and to the non-zero y-intercept in linear REE models. The model predicts that REE analysis at the individual organ-tissue level will not eliminate intercept terms. I demonstrate that the parameters of a linear EE equation can be transformed into the parameters of the underlying ‘latent’ allometric equation. This permits estimates of the allometric scaling of EE in a diverse variety of physiological states that are not represented in the allometric EE literature but are well represented by published linear EE analyses. PMID:25068692

Mathematical model for the contribution of individual organs to non-zero y-intercepts in single and multi-compartment linear models of whole-body energy expenditure.

PubMed

Kaiyala, Karl J

2014-01-01

Mathematical models for the dependence of energy expenditure (EE) on body mass and composition are essential tools in metabolic phenotyping. EE scales over broad ranges of body mass as a non-linear allometric function. When considered within restricted ranges of body mass, however, allometric EE curves exhibit 'local linearity.' Indeed, modern EE analysis makes extensive use of linear models. Such models typically involve one or two body mass compartments (e.g., fat free mass and fat mass). Importantly, linear EE models typically involve a non-zero (usually positive) y-intercept term of uncertain origin, a recurring theme in discussions of EE analysis and a source of confounding in traditional ratio-based EE normalization. Emerging linear model approaches quantify whole-body resting EE (REE) in terms of individual organ masses (e.g., liver, kidneys, heart, brain). Proponents of individual organ REE modeling hypothesize that multi-organ linear models may eliminate non-zero y-intercepts. This could have advantages in adjusting REE for body mass and composition. Studies reveal that individual organ REE is an allometric function of total body mass. I exploit first-order Taylor linearization of individual organ REEs to model the manner in which individual organs contribute to whole-body REE and to the non-zero y-intercept in linear REE models. The model predicts that REE analysis at the individual organ-tissue level will not eliminate intercept terms. I demonstrate that the parameters of a linear EE equation can be transformed into the parameters of the underlying 'latent' allometric equation. This permits estimates of the allometric scaling of EE in a diverse variety of physiological states that are not represented in the allometric EE literature but are well represented by published linear EE analyses.

[Effects of Light Near-Infrared Radiation on Rats Assessed by Succinate Dehydrogenase Activity in Lymphocytes on Blood Smears].

PubMed

Khunderyakova, N V; Zakharchenko, A V; Zakharchenko, M V; Muller, H; Fedotcheva, I; Kondrashova, M N

2015-01-01

Biological effects of light near infrared radiation (850 nm), with modulation acoustic frequency of 101 Hz, was studied. The study was conducted on rats, the effect was recorded by succinate dehydrogenase activity in lymphocytes on the blood smear after administration of the activating dose of adrenaline, which simulates the state of the organism in the early stages of the pathogenic effects (stress). A pronounced regulating effect of infrared radiation on the activity of succinate dehydrogenase in animals activated by adrenaline was shown. Infrared radiation has a normalizing effect reducing the degree of inhibition or activation of the enzyme induced by adrenaline and had no effect on the control animals. Thus, by modulating the activity of succinate dehydrogenase infrared radiation regulates energy production in the mitochondria supported by the most powerful oxidation substrate--succinic acid, which is especially pronounced under stress.

Gamma-radiation effects on luminescence properties of Eu3+ activated LaPO4 phosphor

NASA Astrophysics Data System (ADS)

Vujčić, Ivica; Gavrilović, Tamara; Sekulić, Milica; Mašić, Slobodan; Putić, Slaviša; Papan, Jelena; Dramićanin, Miroslav D.

2018-05-01

Eu3+ activated LaPO4 phosphors were prepared by a high-temperature solid-state method and irradiated to different high-doses gamma-radiation in the 0-4 MGy range. No effects of high-doses of high-energy radiation on phosphor's morphology and structure were observed, as documented by electron microscopy and X-ray diffraction measurements. On the other hand, photoluminescence measurements showed that emission properties of phosphor were affected by gamma-radiation; changes in radiative properties being prominent for absorbed radiation doses up to 250 kGy after which no additional changes are observed. Judd-Ofelt analysis of emission spectra is performed to thoroughly investigate radiative properties of phosphors. Analysis showed that radiative transition probability of Eu3+ emission decreases while non-radiative probability increases upon gamma-irradiation. Quantum efficiency of emission is decreased from about 46% to 35% when Eu3+ doped LaPO4 powders are exposed to gamma-radiation of 250 kGy dose, showing no additional decrease for higher gamma-radiation doses.

Randomized Clinical Trial of Interceptive and Comprehensive Orthodontics

PubMed Central

King, G.J.; Spiekerman, C.F.; Greenlee, G.M.; Huang, G.J.

2012-01-01

Focusing public insurance programs on interceptive orthodontics (IO) may increase access for low-income children. This report presents outcomes from a randomized clinical trial (RCT) comparing IO with comprehensive orthodontics (CO) in Medicaid patients. One hundred seventy pre-adolescents with Medicaid-eligible malocclusions were randomized to IO (n = 86) followed by observation (OBS) or OBS followed by CO (n = 84). One hundred thirty-four completed the trial. Models at pre-treatment (baseline) and following ≤ 2 years of intervention and 2 years of OBS (48 mos) were scored by calibrated examiners using the Peer Assessment Rating (PAR) and Index of Complexity, Outcome and Need (ICON). Overall outcomes and clinically meaningful categorical ICON data on need/acceptability, complexity, and improvement were compared. At baseline, groups were balanced by age, gender, ethnicity, and PAR/ICON scores. Most were minorities. Most (77%) were rated as difficult-to-very difficult. Scores improved significantly for both groups, but CO more than IO (PAR, 18.6 [95%CI 15.1, 22.1] vs.10.1 [95%CI 6.7, 13.4]; ICON, 44.8 [95% CI 39.7, 49.9] vs. 35.2 [95%CI 29.7, 40.6], respectively). On average, IO is effective at reducing malocclusions in Medicaid patients, but less than CO. (ClinicalTrials.gov number CT00067379) PMID:22699670

Security proof of counterfactual quantum cryptography against general intercept-resend attacks and its vulnerability

NASA Astrophysics Data System (ADS)

Zhang, Sheng; Wang, Jian; Tang, Chao-Jing

2012-06-01

Counterfactual quantum cryptography, recently proposed by Noh, is featured with no transmission of signal particles. This exhibits evident security advantages, such as its immunity to the well-known photon-number-splitting attack. In this paper, the theoretical security of counterfactual quantum cryptography protocol against the general intercept-resend attacks is proved by bounding the information of an eavesdropper Eve more tightly than in Yin's proposal [Phys. Rev. A 82 042335 (2010)]. It is also shown that practical counterfactual quantum cryptography implementations may be vulnerable when equipped with imperfect apparatuses, by proving that a negative key rate can be achieved when Eve launches a time-shift attack based on imperfect detector efficiency.

Effects of UVB radiation on Photosynthesis Activity of Wolffia arrhiza as Probed by Chlorophyll Fluorescence Transient

NASA Astrophysics Data System (ADS)

Wang, Gaohong; Hao, Zongjie; Chen, Kun; Liu, Yongding

UV radiation is one major environmental stress for growth of Wolffia arrhiza which is regarded as a good candidate producer for establishing CELSS during extraterrestrial colonization and spaceflight. In this study, we found that UVB radiation inhibited photosynthetic CO2 assimilation activity significantly, and the content of chlorophyll a, chlorophyll b and carotenoids decreased obviously when plants were exposed to UVB radiation for 6 h. High UVB radiation also declined the quantum yield of primary photochemistry (φPo), the quantum yield for electron transport (φEo) and the efficiency per trapped excitation (ψo) in the cells of Wolffia arrhiza simultaneously, while the amount of active PSII reaction centers per excited cross section (RC/CS) and the total number of active reaction center per absorption (RC/ABS) had the same changes under UV-B radiation stress. These results indicated that the effects of UV- B radiation on photosynthesis of Wolffia arrhiza maybe functioned by inhibition the electron transport and inactivation of reaction centers, but the inhibition maybe happen in more than one site in photosynthetic apparatus which is different to that in salt adaptation.

Mobile phone electromagnetic radiation activates MAPK signaling and regulates viability in Drosophila.

PubMed

Lee, Kyu-Sun; Choi, Jong-Soon; Hong, Sae-Yong; Son, Tae-Ho; Yu, Kweon

2008-07-01

Mobile phones are widely used in the modern world. However, biological effects of electromagnetic radiation produced by mobile phones are largely unknown. In this report, we show biological effects of the mobile phone 835 MHz electromagnetic field (EMF) in the Drosophila model system. When flies were exposed to the specific absorption rate (SAR) 1.6 W/kg, which is the proposed exposure limit by the American National Standards Institute (ANSI), more than 90% of the flies were viable even after the 30 h exposure. However, in the SAR 4.0 W/kg strong EMF exposure, viability dropped from the 12 h exposure. These EMF exposures triggered stress response and increased the production of reactive oxygen species. The EMF exposures also activated extracellular signal regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) signaling, but not p38 kinase signaling. Interestingly, SAR 1.6 W/kg activated mainly ERK signaling and expression of an anti-apoptotic gene, whereas SAR 4.0 W/kg strongly activated JNK signaling and expression of apoptotic genes. In addition, SAR 4.0 W/kg amplified the number of apoptotic cells in the fly brain. These findings demonstrate that the exposure limit on electromagnetic radiation proposed by ANSI triggered ERK-survival signaling but the strong electromagnetic radiation activated JNK-apoptotic signaling in Drosophila.

[Effect of NF-κB activation on the radiation response of esophageal cancer cells].

PubMed

Li, Baozhong; Chen, Zhaoli; Zhou, Fang; He, Jie

2014-07-01

To investigate the effect of NF-κB activation on radiation response of esophageal carcinoma. The expression of NF-κB was detected in pretreatment and posttreatment specimens of patients with ESCC by immunohistochemistry. Electrophoretic mobility shift assay (EMSA) and Western blot were used to detect the activation of NF-κB in esophageal cancer cell line KYSE150 cells. SN50, a specific NF-κB inhibitor, was applied to inhibit the activation of NF-κB. Clone formation test was used to detect the radiosensitivity of esophageal cancer cells. The median survival time of patients with activated and inactivated NF-κB in the pretreatment specimens were 16 and 19 months, respectively, with a non-significant difference between the two groups (P > 0.05). As to the patients with activated and inactivated NF-κB in posttreatment specimens, the median survival times were 13 and 35 months, respectively, with a significant difference (P < 0.01) between them. Western blot showed that the cytoplasmic expression of NF-κB was reduced with increasing radiation dose at 1.5 and 3 hours after radiation treatment. However, the expression of NF-κB in the cell nuclei was increased under the same condition, showing a trend of increased nucleus/cytoplasm ratio. The clone number in SN50 group was 96.66, 64.66, 76.66 and 10.00 under 0, 2, 4 and 12 Gy irradiation, which demonstrated a significant difference compared with the control groups (P < 0.001). Our results show that activation of NF-κB is induced by radiotherapy. Activation of NF-κB reduces the outcome of radiation treatment of esophageal cancer patients.

Nrf2 Activation Protects against Solar-Simulated Ultraviolet Radiation in Mice and Humans.

PubMed

Knatko, Elena V; Ibbotson, Sally H; Zhang, Ying; Higgins, Maureen; Fahey, Jed W; Talalay, Paul; Dawe, Robert S; Ferguson, James; Huang, Jeffrey T-J; Clarke, Rosemary; Zheng, Suqing; Saito, Akira; Kalra, Sukirti; Benedict, Andrea L; Honda, Tadashi; Proby, Charlotte M; Dinkova-Kostova, Albena T

2015-06-01

The transcription factor Nrf2 determines the ability to adapt and survive under conditions of electrophilic, oxidative, and inflammatory stress by regulating the expression of elaborate networks comprising nearly 500 genes encoding proteins with versatile cytoprotective functions. In mice, disruption of Nrf2 increases susceptibility to carcinogens and accelerates disease pathogenesis. Paradoxically, Nrf2 is upregulated in established human tumors, but whether this upregulation drives carcinogenesis is not known. Here we show that the incidence, multiplicity, and burden of solar-simulated UV radiation-mediated cutaneous tumors that form in SKH-1 hairless mice in which Nrf2 is genetically constitutively activated are lower than those that arise in their wild-type counterparts. Pharmacologic Nrf2 activation by topical biweekly applications of small (40 nmol) quantities of the potent bis(cyano enone) inducer TBE-31 has a similar protective effect against solar-simulated UV radiation in animals receiving long-term treatment with the immunosuppressive agent azathioprine. Genetic or pharmacologic Nrf2 activation lowers the expression of the pro-inflammatory factors IL6 and IL1β, and COX2 after acute exposure of mice to UV radiation. In healthy human subjects, topical applications of extracts delivering the Nrf2 activator sulforaphane reduced the degree of solar-simulated UV radiation-induced skin erythema, a quantifiable surrogate endpoint for cutaneous damage and skin cancer risk. Collectively, these data show that Nrf2 is not a driver for tumorigenesis even upon exposure to a very potent and complete carcinogen and strongly suggest that the frequent activation of Nrf2 in established human tumors is a marker of metabolic adaptation. ©2015 American Association for Cancer Research.

Nrf2 activation protects against solar-simulated ultraviolet radiation in mice and humans

PubMed Central

Knatko, Elena V.; Ibbotson, Sally H.; Zhang, Ying; Higgins, Maureen; Fahey, Jed W.; Talalay, Paul; Dawe, Robert S.; Ferguson, James; Huang, Jeffrey T.-J.; Clarke, Rosemary; Zheng, Suqing; Saito, Akira; Kalra, Sukirti; Benedict, Andrea L.; Honda, Tadashi; Proby, Charlotte M.; Dinkova-Kostova, Albena T.

2015-01-01

The transcription factor Nrf2 determines the ability to adapt and survive under conditions of electrophilic, oxidative and inflammatory stress by regulating the expression of elaborate networks comprising nearly 500 genes encoding proteins with versatile cytoprotective functions. In mice, disruption of Nrf2 increases susceptibility to carcinogens and accelerates disease pathogenesis. Paradoxically, Nrf2 is upregulated in established human tumors, but whether this upregulation drives carcinogenesis is not known. Here we show that the incidence, multiplicity and burden of solar-simulated UV radiation-mediated cutaneous tumors that form in SKH-1 hairless mice in which Nrf2 is genetically constitutively activated, are lower than those that arise in their wild-type counterparts. Pharmacological Nrf2 activation by topical bi-weekly applications of small (40 nmol) quantities of the potent bis(cyano enone) inducer TBE-31 has a similar protective effect against solar-simulated UV radiation in animals receiving long-term treatment with the immunosuppressive agent azathioprine. Genetic or pharmacological Nrf2 activation lowers the expression of the pro-inflammatory factors interleukin (IL)-6 and IL-1β, and cyclooxygenase (COX)-2 after acute exposure of mice to UV radiation. In healthy human subjects, topical applications of extracts delivering the Nrf2 activator sulforaphane, reduced the degree of solar-simulated UV radiation-induced skin erythema, a quantifiable surrogate end-point for cutaneous damage and skin cancer risk. Collectively, these data show that Nrf2 is not a driver for tumorigenesis even upon exposure to a very potent and complete carcinogen, and strongly suggest that the frequent activation of Nrf2 in established human tumors is a marker of metabolic adaptation. PMID:25804610

p53 activated by AND gate genetic circuit under radiation and hypoxia for targeted cancer gene therapy

PubMed Central

Ding, Miao; Li, Rong; He, Rong; Wang, Xingyong; Yi, Qijian; Wang, Weidong

2015-01-01

Radio-activated gene therapy has been developed as a novel therapeutic strategy against cancer; however, expression of therapeutic gene in peritumoral tissues will result in unacceptable toxicity to normal cells. To restrict gene expression in targeted tumor mass, we used hypoxia and radiation tolerance features of tumor cells to develop a synthetic AND gate genetic circuit through connecting radiation sensitivity promoter cArG6, heat shock response elements SNF1, HSF1 and HSE4 with retroviral vector plxsn. Their construction and dynamic activity process were identified through downstream enhanced green fluorescent protein and wtp53 expression in non-small cell lung cancer A549 cells and in a nude mice model. The result showed that AND gate genetic circuit could be activated by lower required radiation dose (6 Gy) and after activated, AND gate could induce significant apoptosis effects and growth inhibition of cancer cells in vitro and in vivo. The radiation- and hypoxia-activated AND gate genetic circuit, which could lead to more powerful target tumoricidal activity represented a promising strategy for both targeted and effective gene therapy of human lung adenocarcinoma and low dose activation character of the AND gate genetic circuit implied that this model could be further exploited to decrease side-effects of clinical radiation therapy. PMID:26177264

p53 activated by AND gate genetic circuit under radiation and hypoxia for targeted cancer gene therapy.

PubMed

Ding, Miao; Li, Rong; He, Rong; Wang, Xingyong; Yi, Qijian; Wang, Weidong

2015-09-01

Radio-activated gene therapy has been developed as a novel therapeutic strategy against cancer; however, expression of therapeutic gene in peritumoral tissues will result in unacceptable toxicity to normal cells. To restrict gene expression in targeted tumor mass, we used hypoxia and radiation tolerance features of tumor cells to develop a synthetic AND gate genetic circuit through connecting radiation sensitivity promoter cArG6 , heat shock response elements SNF1, HSF1 and HSE4 with retroviral vector plxsn. Their construction and dynamic activity process were identified through downstream enhanced green fluorescent protein and wtp53 expression in non-small cell lung cancer A549 cells and in a nude mice model. The result showed that AND gate genetic circuit could be activated by lower required radiation dose (6 Gy) and after activated, AND gate could induce significant apoptosis effects and growth inhibition of cancer cells in vitro and in vivo. The radiation- and hypoxia-activated AND gate genetic circuit, which could lead to more powerful target tumoricidal activity represented a promising strategy for both targeted and effective gene therapy of human lung adenocarcinoma and low dose activation character of the AND gate genetic circuit implied that this model could be further exploited to decrease side-effects of clinical radiation therapy. © 2015 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer Association.

Parvovirus B19 Passive Transmission by Transfusion of Intercept® Blood System-Treated Platelet Concentrate

PubMed Central

Gowland, Peter; Fontana, Stefano; Stolz, Martin; Andina, Nicola; Niederhauser, Christoph

2016-01-01

Summary Background Pathogen reduction methods for blood components are effective for a large number of viruses though less against small, non-enveloped viruses such as Parvovirus B19 (B19V). This article describes the passive transmission by transfusion of two B19V-contaminated pooled platelet concentrates (PCs) which were treated with the Intercept® blood pathogen reduction system. Case Reports Two transfusion cases of B19V-contaminated Intercept-treated pooled PCs were described. Due to the analysis delay, the PCs were already transfused. The viral content of each donation was 4.87 × 1010 IU/ml in case 1and 1.46 × 108 IU/ml in case 2. B19V (52 IU/ml) was detected in the recipient of the case 1 PC, whereas no virus could be detected in the case 2 PC recipient. A B19V IgM response and a transient boost of the underlying B19V IgG immune status and was observed in recipient 1. Recipient of the case 2 PC remained B19V IgG- and IgM-negative. B19V DNA sequence and phylogenetic analysis revealed a 100% homology between donor and recipient. Conclusion This report describes passive B19V transmission by a PC with very high B19 viral load which elicited a transient boost of the B19V immunity, but not by a PC with a lower B19V content, suggesting that there is a B19 viral load threshold value at which B19V inactivation is exceeded. PMID:27403092

Solar Activity, Ultraviolet Radiation and Consequences in Birds in Mexico City, 2001- 2002

NASA Astrophysics Data System (ADS)

Valdes, M.; Velasco, V.

2008-12-01

Anomalous behavior in commercial and pet birds in Mexico City was reported during 2002 by veterinarians at the Universidad Nacional Autonoma de Mexico. This was attributed to variations in the surrounding luminosity. The solar components, direct, diffuse, global, ultraviolet band A and B, as well as some meteorological parameters, temperature, relative humidity, and precipitation, were then analyzed at the Solar Radiation Laboratory. Although the total annual radiance of the previously mentioned radiation components did not show important changes, ultraviolet Band-B solar radiation did vary significantly. During 2001 the total annual irradiance , 61.05 Hjcm² to 58.32 Hjcm², was 1.6 standard deviations lower than one year later, in 2002 and increased above the mean total annual irradiance, to 65.75 Hjcm², 2.04 standard deviations, giving a total of 3.73 standard deviations for 2001-2002. Since these differences did not show up clearly in the other solar radiation components, daily extra-atmosphere irradiance was analyzed and used to calculate the total annual extra-atmosphere irradiance, which showed a descent for 2001. Our conclusions imply that Ultraviolet Band-B solar radiation is representative of solar activity and has an important impact on commercial activity related with birds.

Validation of zero-order feedback strategies for medium range air-to-air interception in a horizontal plane

NASA Technical Reports Server (NTRS)

Shinar, J.

1982-01-01

A zero order feedback solution of a variable speed interception game between two aircraft in the horizontal plane, obtained by using the method of forced singular perturbation (FSP), is compared with the exact open loop solution. The comparison indicates that for initial distances of separation larger than eight turning radii of the evader, the accuracy of the feedback approximation is better than one percent. The result validates the zero order FSP approximation for medium range air combat analysis.

Inflammatory bowel diseases activity in patients undergoing pelvic radiation therapy.

PubMed

Annede, Pierre; Seisen, Thomas; Klotz, Caroline; Mazeron, Renaud; Maroun, Pierre; Petit, Claire; Deutsch, Eric; Bossi, Alberto; Haie-Meder, Christine; Chargari, Cyrus; Blanchard, Pierre

2017-02-01

Few studies with contradictory results have been published on the safety of pelvic radiation therapy (RT) in patients with inflammatory bowel disease (IBD). From 1989 to 2015, a single center retrospective analysis was performed including all IBD patients who received pelvic external beam radiation therapy (EBRT) or brachytherapy (BT) for a pelvic malignancy. Treatment characteristics, IBD activity and gastrointestinal (GI) toxicity were examined. Overall, 28 patients with Crohn's disease (CD) (n=13) or ulcerative colitis (n=15) were included in the present study. Median follow-up time after irradiation was 5.9 years. Regarding IBD activity, only one and two patients experienced a severe episode within and after 6 months of follow-up, respectively. Grade 3/4 acute GI toxicity occurred in 3 (11%) patients, whereas one (3.6%) patient experienced late grade 3/4 GI toxicity. Only patients with rectal IBD location (P=0.016) or low body mass index (BMI) (P=0.012) experienced more severe IBD activity within or after 6 months following RT, respectively. We report an acceptable tolerance of RT in IBD patients with pelvic malignancies. Specifically, a low risk of uncontrolled flare-up was observed.

Target selection for a hypervelocity asteroid intercept vehicle flight validation mission

NASA Astrophysics Data System (ADS)

Wagner, Sam; Wie, Bong; Barbee, Brent W.

2015-02-01

Asteroids and comets have collided with the Earth in the past and will do so again in the future. Throughout Earth's history these collisions have played a significant role in shaping Earth's biological and geological histories. The planetary defense community has been examining a variety of options for mitigating the impact threat of asteroids and comets that approach or cross Earth's orbit, known as near-Earth objects (NEOs). This paper discusses the preliminary study results of selecting small (100-m class) NEO targets and mission analysis and design trade-offs for validating the effectiveness of a Hypervelocity Asteroid Intercept Vehicle (HAIV) concept, currently being investigated for a NIAC (NASA Advanced Innovative Concepts) Phase 2 study. In particular this paper will focus on the mission analysis and design for single spacecraft direct impact trajectories, as well as several mission types that enable a secondary rendezvous spacecraft to observe the HAIV impact and evaluate it's effectiveness.

The RaDIATE High-Energy Proton Materials Irradiation Experiment at the Brookhaven Linac Isotope Producer Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ammigan, Kavin; et al.

The RaDIATE collaboration (Radiation Damage In Accelerator Target Environments) was founded in 2012 to bring together the high-energy accelerator target and nuclear materials communities to address the challenging issue of radiation damage effects in beam-intercepting materials. Success of current and future high intensity accelerator target facilities requires a fundamental understanding of these effects including measurement of materials property data. Toward this goal, the RaDIATE collaboration organized and carried out a materials irradiation run at the Brookhaven Linac Isotope Producer facility (BLIP). The experiment utilized a 181 MeV proton beam to irradiate several capsules, each containing many candidate material samples formore » various accelerator components. Materials included various grades/alloys of beryllium, graphite, silicon, iridium, titanium, TZM, CuCrZr, and aluminum. Attainable peak damage from an 8-week irradiation run ranges from 0.03 DPA (Be) to 7 DPA (Ir). Helium production is expected to range from 5 appm/DPA (Ir) to 3,000 appm/DPA (Be). The motivation, experimental parameters, as well as the post-irradiation examination plans of this experiment are described.« less

Proposed algorithm for determining the delta intercept of a thermocouple psychrometer curve

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurzmack, M.A.

1993-07-01

The USGS Hydrologic Investigations Program is currently developing instrumentation to study the unsaturated zone at Yucca Mountain in Nevada. Surface-based boreholes up to 2,500 feet in depth will be drilled, and then instrumented in order to define the water potential field within the unsaturated zone. Thermocouple psychrometers will be used to monitor the in-situ water potential. An algorithm is proposed for simply and efficiently reducing a six wire thermocouple psychrometer voltage output curve to a single value, the delta intercept. The algorithm identifies a plateau region in the psychrometer curve and extrapolates a linear regression back to the initial startmore » of relaxation. When properly conditioned for the measurements being made, the algorithm results in reasonable results even with incomplete or noisy psychrometer curves over a 1 to 60 bar range.« less

Active Control of Sound Radiation due to Subsonic Wave Scattering from Discontinuities on Thin Elastic Beams.

NASA Astrophysics Data System (ADS)

Guigou, Catherine Renee J.

1992-01-01

Much progress has been made in recent years in active control of sound radiation from vibrating structures. Reduction of the far-field acoustic radiation can be obtained by directly modifying the response of the structure by applying structural inputs rather than by adding acoustic sources. Discontinuities, which are present in many structures are often important in terms of sound radiation due to wave scattering behavior at their location. In this thesis, an edge or boundary type discontinuity (clamped edge) and a point discontinuity (blocking mass) are analytically studied in terms of sound radiation. When subsonic vibrational waves impinge on these discontinuities, large scattered sound levels are radiated. Active control is then achieved by applying either control forces, which approximate shakers, or pairs of control moments, which approximate piezoelectric actuators, near the discontinuity. Active control of sound radiation from a simply-supported beam is also examined. For a single frequency, the flexural response of the beam subject to an incident wave or an input force (disturbance) and to control forces or control moments is expressed in terms of waves of both propagating and near-field types. The far-field radiated pressure is then evaluated in terms of the structural response, using Rayleigh's formula or a stationary phase approach, depending upon the application. The control force and control moment magnitudes are determined by optimizing a quadratic cost function, which is directly related to the control performance. On determining the optimal control complex amplitudes, these can be resubstituted in the constitutive equations for the system under study and the minimized radiated fields can be evaluated. High attenuation in radiated sound power and radiated acoustic pressure is found to be possible when one or two active control actuators are located near the discontinuity, as is shown to be mostly associated with local changes in beam response near

Acute Cerebrovascular Radiation Syndrome: Radiation Neurotoxicity , mechanisms of CNS radiation injury, advanced countermeasures for Radiation Protection of Central Nervous System.

NASA Astrophysics Data System (ADS)

Popov, Dmitri; Jones, Jeffrey; Maliev, Slava

Key words: Cerebrovascular Acute Radiation Syndrome (Cv ARS), Radiation Neurotoxins (RNT), Neurotransmitters, Radiation Countermeasures, Antiradiation Vaccine (ArV), Antiradiation Blocking Antibodies, Antiradiation Antidote. Psychoneuroimmunology, Neurotoxicity. ABSTRACT: To review the role of Radiation Neurotoxins in triggering, developing of radiation induced central nervous system injury. Radiation Neurotoxins - rapidly acting blood toxic lethal agent, which activated after irradiation and concentrated, circulated in interstitial fluid, lymph, blood with interactions with cell membranes, receptors and cell compartments. Radiation Neurotoxins - biological molecules with high enzymatic activity and/or specific lipids and activated or modified after irradiation. The Radiation Neurotoxins induce increased permeability of blood vessels, disruption of the blood-brain barrier, blood-cerebrospinal fluid (CSF) barrier and developing severe disorder of blood macro- and micro-circulation. Principles of Radiation Psychoneuro-immunology and Psychoneuro-allergology were applied for determination of pathological processes developed after irradiation or selective administration of Radiation Neurotoxins to radiation naïve mammals. Effects of radiation and exposure to radiation can develop severe irreversible abnormalities of Central Nervous System, brain structures and functions. Antiradiation Vaccine - most effective, advanced methods of protection, prevention, mitigation and treatment and was used for of Acute Radiation Syndromes and elaboration of new technology for immune-prophylaxis and immune-protection against ϒ, Heavy Ion, Neutron irradiation. Results of experiments suggested that blocking, antitoxic, antiradiation antibodies can significantly reduce toxicity of Radiation Toxins. New advanced technology include active immune-prophylaxis with Antiradiation Vaccine and Antiradiation therapy that included specific blocking antibodies to Radiation Neurotoxins

Radiation-induced inflammatory markers of brain injury are modulated by PPARdelta activation in vitro and in vivo

NASA Astrophysics Data System (ADS)

Schnegg, Caroline Isabel

As a result of improvements in cancer therapy and health care, the population of long-term cancer survivors is growing. For these approximately 12 million long-term cancer survivors, brain metastases are a significant risk. Fractionated partial or whole-brain irradiation (fWBI) is often required to treat both primary and metastatic brain cancer. Radiation-induced normal tissue injury, including progressive cognitive impairment, however, can significantly affect the well-being of the approximately 200,000 patients who receive these treatments each year. Recent reports indicate that radiation-induced brain injury is associated with chronic inflammatory and oxidative stress responses, as well as increased microglial activation in the brain. Anti-inflammatory drugs may, therefore, be a beneficial therapy to mitigate radiation-induced brain injury. We hypothesized that activation of peroxisomal proliferator activated receptor delta (PPARō) would prevent or ameliorate radiation-induced brain injury, including cognitive impairment, in part, by alleviating inflammatory responses in microglia. For our in vitro studies, we hypothesized that PPARō activation would prevent the radiation-induced inflammatory response in microglia following irradiation. Incubating BV-2 murine microglial cells with the (PPAR)ō agonist, L-165041, prevented the radiation-induced increase in: i) intracellular ROS generation, ii) Cox-2 and MCP-1 expression, and iii) IL-1β and TNF-α message levels. This occured, in part, through PPARō-mediated modulation of stress activated kinases and proinflammatory transcription factors. PPARō inhibited NF-κB via transrepression by physically interacting with the p65 subunit, and prevented activation of the PKCα/MEK1/2/ERK1/2/AP-1 pathway by inhibiting the radiation-induced increase in intracellular ROS generation. These data support the hypothesis that PPARō activation can modulate the radiation-induced oxidative stress and inflammatory

[The activity of prooxidant-antioxidant system in loach embryos under the action of microwave radiation].

PubMed

Iaremchuk, M M; Dyka, M V; Sanahurs'kyĭ, D I

2014-01-01

Electromagnetic radiation (EMR) affects biological organisms, primarily on the cellular level. However, the effects of EMR at low-intensity exposure on animals and state of metabolic systems are not fully defined yet. Thus, research of microwave radiation influence on the processes of lipid peroxidation and antioxidant protection system is important for understanding the mechanisms of EMR action on the cell, in particular, and organism development on the whole. The content of lipid peroxidation products--lipid hydroperoxides, thiobarbituric acid reactive substances and the activity of antioxidant enzymes--superoxide dismutase, glutathione peroxidase and catalase in loach embryos under the action of microwave radiation (GSM-900 MHz, SAR = 1.1 Vt/kg) lasting 1; 5; 10 and 20 min during early embryogenesis were studied. It has been found that content of lipid peroxidation products in germ cells undergoes significant changes under the action of low-intensity EMR. The effect of microwave radiation (1, 5, 10 min) leads to the increase of superoxide dismutase activity, nevertheless, 20 min exposure decreased this index to the level of control values as it is shown. It has been established that EMR at frequencies used for mobile communications reduce the activity of antioxidant protection system components, especially catalase and glutathione peroxidase. The growth of catalase activity at the 10-cell stage of blastomere division (P < 0.05) is an exception. The results of two-way analysis of variance attest that microwave radiation factor causes the large part of all observable modifications.

Synoptic Traveling Weather Systems on Mars: Effects of Radiatively-Active Water Ice Clouds

NASA Astrophysics Data System (ADS)

Hollingsworth, Jeffery L.; Kahre, Melinda A.; Haberle, Robert; Atsuki Urata, Richard

2016-10-01

Atmospheric aerosols on Mars are critical in determining the nature of its thermal structure, its large-scale circulation, and hence the overall climate of the planet. We conduct multi-annual simulations with the latest version of the NASA Ames Mars global climate model (GCM), gcm2.3+, that includes a modernized radiative-transfer package and complex water-ice cloud microphysics package which permit radiative effects and interactions of suspended atmospheric aerosols (e.g., water ice clouds, water vapor, dust, and mutual interactions) to influence the net diabatic heating. Results indicate that radiatively active water ice clouds profoundly affect the seasonal and annual mean climate. The mean thermal structure and balanced circulation patterns are strongly modified near the surface and aloft. Warming of the subtropical atmosphere at altitude and cooling of the high latitude atmosphere at low levels takes place, which increases the mean pole-to-equator temperature contrast (i.e., "baroclinicity"). With radiatively active water ice clouds (RAC) compared to radiatively inert water ice clouds (nonRAC), significant changes in the intensity of the mean state and forced stationary Rossby modes occur, both of which affect the vigor and intensity of traveling, synoptic period weather systems. Such weather systems not only act as key agents in the transport of heat and momentum beyond the extent of the Hadley circulation, but also the transport of trace species such as water vapor, water ice-clouds, dust and others. The northern hemisphere (NH) forced Rossby waves and resultant wave train are augmented in the RAC case: the modes are more intense and the wave train is shifted equatorward. Significant changes also occur within the subtropics and tropics. The Rossby wave train sets up, combined with the traveling synoptic-period weather systems (i.e., cyclones and anticyclones), the geographic extent of storm zones (or storm tracks) within the NH. A variety of circulation

Synoptic Traveling Weather Systems on Mars: Effects of Radiatively-Active Water Ice Clouds

NASA Technical Reports Server (NTRS)

Hollingsworth, Jeffery; Kahre, Melinda; Haberle, Robert; Urata, Richard

2017-01-01

Atmospheric aerosols on Mars are critical in determining the nature of its thermal structure, its large-scale circulation, and hence the overall climate of the planet. We conduct multi-annual simulations with the latest version of the NASA Ames Mars global climate model (GCM), gcm2.3+, that includes a modernized radiative-transfer package and complex water-ice cloud microphysics package which permit radiative effects and interactions of suspended atmospheric aerosols (e.g., water ice clouds, water vapor, dust, and mutual interactions) to influence the net diabatic heating. Results indicate that radiatively active water ice clouds profoundly affect the seasonal and annual mean climate. The mean thermal structure and balanced circulation patterns are strongly modified near the surface and aloft. Warming of the subtropical atmosphere at altitude and cooling of the high latitude atmosphere at low levels takes place, which increases the mean pole-to-equator temperature contrast (i.e., "baroclinicity"). With radiatively active water ice clouds (RAC) compared to radiatively inert water ice clouds (nonRAC), significant changes in the intensity of the mean state and forced stationary Rossby modes occur, both of which affect the vigor and intensity of traveling, synoptic period weather systems. Such weather systems not only act as key agents in the transport of heat and momentum beyond the extent of the Hadley circulation, but also the transport of trace species such as water vapor, water ice-clouds, dust and others. The northern hemisphere (NH) forced Rossby waves and resultant wave train are augmented in the RAC case: the modes are more intense and the wave train is shifted equatorward. Significant changes also occur within the subtropics and tropics. The Rossby wave train sets up, combined with the traveling synoptic period weather systems (i.e., cyclones and anticyclones), the geographic extent of storm zones (or storm tracks) within the NH. A variety of circulation

Synoptic Traveling Weather Systems on Mars: Effects of Radiatively-Active Water Ice Clouds

NASA Technical Reports Server (NTRS)

Hollingsworth, Jeffery; Kahre, Melinda; Haberle, Robert; Urata, Richard

2017-01-01

Atmospheric aerosols on Mars are critical in determining the nature of its thermal structure, its large-scale circulation, and hence the overall climate of the planet. We conduct multi-annual simulations with the latest version of the NASA Ames Mars global climate model (GCM), gcm2.3+, that includes a modernized radiative-transfer package and complex water-ice cloud microphysics package which permit radiative effects and interactions of suspended atmospheric aerosols (e.g., water ice clouds, water vapor, dust, and mutual interactions) to influence the net diabatic heating. Results indicate that radiatively active water ice clouds profoundly affect the seasonal and annual mean climate. The mean thermal structure and balanced circulation patterns are strongly modified near the surface and aloft. Warming of the subtropical atmosphere at altitude and cooling of the high latitude atmosphere at low levels takes place, which increases the mean pole-to-equator temperature contrast (i.e., "baroclinicity"). With radiatively active water ice clouds (RAC) compared to radiatively inert water ice clouds (nonRAC), significant changes in the intensity of the mean state and forced stationary Rossby modes occur, both of which affect the vigor and intensity of traveling, synoptic period weather systems.Such weather systems not only act as key agents in the transport of heat and momentum beyond the extent of the Hadley circulation, but also the transport of trace species such as water vapor, water ice-clouds, dust and others. The northern hemisphere (NH) forced Rossby waves and resultant wave train are augmented in the RAC case: the modes are more intense and the wave train is shifted equatorward. Significant changes also occur within the subtropics and tropics. The Rossby wave train sets up, combined with the traveling synoptic period weather systems (i.e., cyclones and anticyclones), the geographic extent of storm zones (or storm tracks) within the NH. A variety of circulation

Modern Radiotherapy Concepts and the Impact of Radiation on Immune Activation

PubMed Central

Deloch, Lisa; Derer, Anja; Hartmann, Josefin; Frey, Benjamin; Fietkau, Rainer; Gaipl, Udo S.

2016-01-01

Even though there is extensive research carried out in radiation oncology, most of the clinical studies focus on the effects of radiation on the local tumor tissue and deal with normal tissue side effects. The influence of dose fractionation and timing particularly with regard to immune activation is not satisfactorily investigated so far. This review, therefore, summarizes current knowledge on concepts of modern radiotherapy (RT) and evaluates the potential of RT for immune activation. Focus is set on radiation-induced forms of tumor cell death and consecutively the immunogenicity of the tumor cells. The so-called non-targeted, abscopal effects can contribute to anti-tumor responses in a specific and systemic manner and possess the ability to target relapsing tumor cells as well as metastases. The impact of distinct RT concepts on immune activation is outlined and pre-clinical evidence and clinical observations on RT-induced immunity will be discussed. Knowledge on the radiosensitivity of immune cells as well as clinical evidence for enhanced immunity after RT will be considered. While stereotactic ablative body radiotherapy seem to have a beneficial outcome over classical RT fractionation in pre-clinical animal models, in vitro model systems suggest an advantage for classical fractionated RT for immune activation. Furthermore, the optimal approach may differ based on the tumor site and/or genetic signature. These facts highlight that clinical trials are urgently needed to identify whether high-dose RT is superior to induce anti-tumor immune responses compared to classical fractionated RT and in particular how the outcome is when RT is combined with immunotherapy in selected tumor entities. PMID:27379203

Active Thermal Extraction and Temperature Sensing of Near-field Thermal Radiation

DOE PAGES

Ding, D.; Kim, T.; Minnich, A. J.

2016-09-06

Recently, we proposed an active thermal extraction (ATX) scheme that enables thermally populated surface phonon polaritons to escape into the far-field. The concept is based on a fluorescence upconversion process that also occurs in laser cooling of solids (LCS). Here, we present a generalized analysis of our scheme using the theoretical framework for LCS. We show that both LCS and ATX can be described with the same mathematical formalism by replacing the electron-phonon coupling parameter in LCS with the electron-photon coupling parameter in ATX. Using this framework, we compare the ideal efficiency and power extracted for the two schemes andmore » examine the parasitic loss mechanisms. As a result, this work advances the application of ATX to manipulate near-field thermal radiation for applications such as temperature sensing and active radiative cooling.« less

Active control of spectral detail radiated by an air-loaded impacted membrane

NASA Astrophysics Data System (ADS)

Rollow, J. Douglas, IV

An active control system is developed to independently operate on the vibration of individual modes of an air-loaded drum head, resulting in changes in the acoustic field radiated from the structure. The timbre of the system is investigated, and techniques for changing the characteristic frequencies by means of the control system are proposed. A feedforward control system is constructed for empirical investigation of this approach, creating a musical instrument which can produce a variety of sounds not available with strictly mechanical systems. The work is motivated by applications for actively controlled structures, active control of sound quality, and musical acoustics. The instrument consists of a Mylar timpano head stretched over an enclosure which has been outfitted with electroacoustic drivers. Sensors are arranged on the surface of the drum head and combined to measure modal vibration, and the array of drivers allows independent control of these modes. A signal processor is used to form modal control filters which can modify the loading of each mode, changing the time-dependent and spectral characteristics, and therefore the timbre, of the radiated sound. A theoretical formulation of active control of structural vibration by means of fluid-coupled actuators is expressed, and computational solutions show the effects of fluid loading and the radiated field. Experimental results with the new instrument are shown, with implementations of the control system providing a demonstrated degree of control, and illustrating several limitations of such systems.

Leaf traits in relation to crown development, light interception and growth of elite families of loblolly and slash pine.

PubMed

Chmura, Daniel J; Tjoelker, Mark G

2008-05-01

Crown architecture and size influence leaf area distribution within tree crowns and have large effects on the light environment in forest canopies. The use of selected genotypes in combination with silvicultural treatments that optimize site conditions in forest plantations provide both a challenge and an opportunity to study the biological and environmental determinants of forest growth. We investigated tree growth, crown development and leaf traits of two elite families of loblolly pine (Pinus taeda L.) and one family of slash pine (P. elliottii Mill.) at canopy closure. Two contrasting silvicultural treatments -- repeated fertilization and control of competing vegetation (MI treatment), and a single fertilization and control of competing vegetation treatment (C treatment) -- were applied at two experimental sites in the West Gulf Coastal Plain in Texas and Louisiana. At a common tree size (diameter at breast height), loblolly pine trees had longer and wider crowns, and at the plot-level, intercepted a greater fraction of photosynthetic photon flux than slash pine trees. Leaf-level, light-saturated assimilation rates (A(max)) and both mass- and area-based leaf nitrogen (N) decreased, and specific leaf area (SLA) increased with increasing canopy depth. Leaf-trait gradients were steeper in crowns of loblolly pine trees than of slash pine trees for SLA and leaf N, but not for A(max). There were no species differences in A(max), except in mass-based photosynthesis in upper crowns, but the effect of silvicultural treatment on A(max) differed between sites. Across all crown positions, A(max) was correlated with leaf N, but the relationship differed between sites and treatments. Observed patterns of variation in leaf properties within crowns reflected acclimation to developing light gradients in stands with closing canopies. Tree growth was not directly related to A(max), but there was a strong correlation between tree growth and plot-level light interception in both

Impacts of Wildfire on Interception Losses and Net Precipitation in a Sub-Alpine Rocky Mountain Watershed in Alberta, Canada.

NASA Astrophysics Data System (ADS)

Williams, C.; Silins, U.; Wagner, M. J.; Bladon, K. D.; Martens, A. M.; Anderson, A.; Stone, M.; Emelko, M. B.

2014-12-01

Interception of precipitation in sub-alpine forests is likely to be strongly reduced after wildfire, potentially producing large increases in net precipitation. Objectives of this study were to describe changes in rainfall and snow interception, and net precipitation after the severe 2003 Lost Creek wildfire as part of the Southern Rockies Watershed Project in the south-west Rocky Mountains of Alberta, Canada. Throughfall troughs and stemflow gauges were used to explore relationships between throughfall, stemflow, and net rainfall with variation in gross rainfall in burned and undisturbed stands during the summers of 2006-2008. These relationships were used to scale the effects of the wildfire on net rainfall for the first decade after the wildfire (2004-2013) using a 10 year rainfall record in the watershed. Annual snowpack surveys (5 snow courses in each of burned and reference stands) measured peak snowpack depth, density, and snow water equivalent (SWE) for this same period. Mean annual P was 1140 mm (684-1519 mm) during the first 10 years after the wildfire, with 61% falling as snow. Throughfall and stemflow in the burned forest accounted for 86% and 7% of gross rainfall, respectively, compared with 53% and 0.002% in the unburned stands in the summers of 2006-2008. Scaled rainfall interception relationships (=f(rainfall event size)) indicated annual increases in net rainfall were 192 mm/yr (133-347 mm) for 10 years after the fire. Similarly, mean increases in peak SWE were 134 mm/yr (93-216 mm). Collectively, the mean increase in net precipitation was 325 mm/yr (226-563 mm; 29%) for the first decade after the wildfire. Hydrologic forcing by increased net precipitation may be a particularly important element of wildfire impacts on sub-alpine watersheds. Furthermore, because of the very slow growth rates of sub-alpine forests, increases in net precipitation are likely to persist and affect precipitation-runoff relationships for decades in these environments.

Engineering low phorbol ester Jatropha curcas seed by intercepting casbene biosynthesis.

PubMed

Li, Chunhong; Ng, Ailing; Xie, Lifen; Mao, Huizhu; Qiu, Chengxiang; Srinivasan, Ramachandran; Yin, Zhongchao; Hong, Yan

2016-01-01

Casbene is a precursor to phorbol esters and down-regulating casbene synthase effectively reduces phorbol ester biosynthesis. Seed-specific reduction of phorbol ester (PE) helps develop Jatropha seed cake for animal nutrition. Phorbol esters (PEs) are diterpenoids present in some Euphorbiaceae family members like Jatropha curcas L. (Jatropha), a tropical shrub yielding high-quality oil suitable as feedstock for biodiesel and bio jet fuel. Jatropha seed contains up to 40 % of oil and can produce oil together with cake containing high-quality proteins. However, skin-irritating and cancer-promoting PEs make Jatropha cake meal unsuitable for animal nutrition and also raise some safety and environmental concerns on its planting and processing. Two casbene synthase gene (JcCASA163 and JcCASD168) homologues were cloned from Jatropha genome and both genes were highly expressed during seed development. In vitro functional analysis proved casbene synthase activity of JcCASA163 in converting geranylgeranyl diphosphate into casbene which has been speculated to be the precursor to PEs. A seed-specific promoter driving inverted repeats for RNAi interference targeting at either JcCASA163 or both genes could effectively down-regulate casbene synthase gene expression with concurrent marked reduction of PE level (by as much as 85 %) in seeds with no pleiotropic effects observed. Such engineered low PE in seed was heritable and co-segregated with the transgene. Our work implicated casbene synthase in Jatropha PE biosynthesis and provided evidence for casbene being the precursor for PEs. The success in reducing seed PE content through down-regulation of casbene synthase demonstrates the feasibility of intercepting PE biosynthesis in Jatropha seed to help address safety concerns on Jatropha plantation and seed processing and facilitate use of its seed protein for animal nutrition.

[INFLUENCE OF IONIZING RADIATION ON THE LOCOMOTOR ACTIVITY AND BODY WEIGHT OF RATS].

PubMed

Saimova, A; Chaizhunusоva, N; Kairkhanova, Y; Uzbеkоv, D; Hоshi, М

2017-02-01

The aim of our study was to study influence of ionizing radiation on the locomotor activity and body weight of rats, for this animals was irradiated by via inhalation. Beta- emitter 56Mn was obtained by neutron activation of powdered MnО2 by using nuclear reactor IVG.1M (experimental facility «Baikal-1», Kurchatov, Kazakhstan). Exposure of rats to radioactive powder had two way, the first experiment was contained only air filter for animal's breathing and the second with the system of forced ventilation. Also we developed the method for observation of the locomotor activity of rats, based on quantitative data. The experiment was conducted on 8 «Wistar» breed white laboratory rats. Statistical analysis was performed using descriptive statistics and non-parametric test. Based on our data, we can say that our method has the advantage over the others is that there is no need to move about the animal out of the box in the test field. So we reduce animal stress factor, as the transfer of an animal from one to second place creates additional stress for him. The initial activity of the pulverized powder in both experiments were 2,74х108Bq, but in the second experiment when we used the system of forced ventilation, internal radiation doses were 0.041±0.0075 Gy, this didn't have effect on locomotor activity of rats (Z= -0,841, р=0,4). In the first experiment where we used only air filter for animal's breathing internal radiation doses were 0.15±0.025 Gr, that showed a decrease in locomotor activity in rats (Z=-6,653, р=0,001). After exposure to ionizing radiation changes in the mammals' weight were not found. Thus, based on our data we have made conclusion, that even after a single irradiation at low dose 0.15±0.025 Gr changes occur in the nervous system.

A dynamic analysis of the radiation excitation from the activation of a current collecting system in space

NASA Technical Reports Server (NTRS)

Wang, J.; Hastings, D. E.

1991-01-01

Current collecting systems moving in the ionosphere will induce electromagnetic wave radiation. The commonly used static analysis is incapable of studying the situation when such systems undergo transient processes. A dynamic analysis has been developed, and the radiation excitation processes are studied. This dynamic analysis is applied to study the temporal wave radiation from the activation of current collecting systems in space. The global scale electrodynamic interactions between a space-station-like structure and the ionospheric plasma are studied. The temporal evolution and spatial propagation of the electric wave field after the activation are described. The wave excitations by tethered systems are also studied. The dependencies of the temporal Alfven wave and lower hybrid wave radiation on the activation time and the space system structure are discussed. It is shown that the characteristics of wave radiation are determined by the matching of two sets of characteristic frequencies, and a rapid change in the current collection can give rise to substantial transient radiation interference. The limitations of the static and linear analysis are examined, and the condition under which the static assumption is valid is obtained.

Genius Sand: A Miniature Kill Vehicle Technology to Support Boost Phase Intercepts and Midcourse Engagements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ledebuhr, A.G.; Ng, L.C.; Kordas, J.F.

2002-06-30

This paper summarizes Lawrence Livermore National Laboratory's (LLNL) approach to a proposed Technology Demonstration program for the development of a new class of miniature kill vehicles (MKVs), that they have termed Genius Sand (GS). These miniaturized kinetic kill vehicles offer new capabilities for boost phase intercept (BPI) missions, as well as midcourse intercepts and the defeat of advanced countermeasures. The specific GS MKV properties will depend on the choice of mission application and system architecture, as well as the level of coordinated or autonomous operations in these missions. In general the GS MKVs will mass from between 1 to 5more » kilograms and have several hundred meters per second of {Delta}v and be capable of several g's of acceleration. Based on the results of their previous study effort, they believe that it is feasible to develop and integrate the required technologies into a fully functional GS MKV prototype within the scope of a three-year development effort. They will discuss some of the system architecture trades and applicable technologies that can be applied in an operational MKV system, as a guide to focus any technology demonstration program. They will present the results of a preliminary 6DOF analysis to determine the minimum capabilities of an MKV system. They also will discuss a preliminary design configuration of a 2 kg GS MKV that has between 300-500 m/s of {Delta}v and has at least 2-g's of acceleration capability. They believe a successful GS MKV development effort will require not only a comprehensive component miniaturization program, but a rapid hardware prototyping process, and the ability to utilize high fidelity ground testing methodologies.« less

Effects of planting density and genotype on canopy size, canopy structure, and growth of 25-year-old loblolly pine stands in southeastern Oklahoma

Treesearch

Thomas C. Hennessey; Rodney E. Will; Thomas B. Lynch; Robert Heinemann; Randal Holeman; Dennis Wilson; Keith Anderson; Gregory Campbell

2013-01-01

Leaf biomass and its display within the canopy are important driving variables of stand growth because they reflect a tree or stand’s capacity to intercept radiation, reduce carbon dioxide, and transpire water. We determined the effects of planting density (4- by 4-, 6- by 6-, 8- by 8-, and 10- by 10-foot spacing) on annual needle fall biomass, intercepted radiation,...

Radiation Protection Studies of International Space Station Extravehicular Activity Space Suits

NASA Technical Reports Server (NTRS)

Cucinotta, Francis A. (Editor); Shavers, Mark R. (Editor); Saganti, Premkumar B. (Editor); Miller, Jack (Editor)

2003-01-01

This publication describes recent investigations that evaluate radiation shielding characteristics of NASA's and the Russian Space Agency's space suits. The introduction describes the suits and presents goals of several experiments performed with them. The first chapter provides background information about the dynamic radiation environment experienced at ISS and summarized radiation health and protection requirements for activities in low Earth orbit. Supporting studies report the development and application of a computer model of the EMU space suit and the difficulty of shielding EVA crewmembers from high-energy reentrant electrons, a previously unevaluated component of the space radiation environment. Chapters 2 through 6 describe experiments that evaluate the space suits' radiation shielding characteristics. Chapter 7 describes a study of the potential radiological health impact on EVA crewmembers of two virtually unexamined environmental sources of high-energy electrons-reentrant trapped electrons and atmospheric albedo or "splash" electrons. The radiological consequences of those sources have not been evaluated previously and, under closer scrutiny. A detailed computational model of the shielding distribution provided by components of the NASA astronauts' EMU is being developed for exposure evaluation studies. The model is introduced in Chapters 8 and 9 and used in Chapter 10 to investigate how trapped particle anisotropy impacts female organ doses during EVA. Chapter 11 presents a review of issues related to estimating skin cancer risk form space radiation. The final chapter contains conclusions about the protective qualities of the suit brought to light form these studies, as well as recommendations for future operational radiation protection.

Using Multisite Experiments to Study Cross-Site Variation in Treatment Effects: A Hybrid Approach with Fixed Intercepts and A Random Treatment Coefficient

ERIC Educational Resources Information Center

Bloom, Howard S.; Raudenbush, Stephen W.; Weiss, Michael J.; Porter, Kristin

2017-01-01

The present article considers a fundamental question in evaluation research: "By how much do program effects vary across sites?" The article first presents a theoretical model of cross-site impact variation and a related estimation model with a random treatment coefficient and fixed site-specific intercepts. This approach eliminates…

Trade-offs between light interception and leaf water shedding: a comparison of shade- and sun-adapted species in a subtropical rainforest.

PubMed

Meng, Fengqun; Cao, Rui; Yang, Dongmei; Niklas, Karl J; Sun, Shucun

2014-01-01

Species in high-rainfall regions have two major alternative approaches to quickly drain off water, i.e., increasing leaf inclination angles relative to the horizontal plane, or developing long leaf drip tips. We hypothesized that shade-adapted species will have more pronounced leaf drip tips but not greater inclination angles (which can reduce the ability to intercept light) compared to sun-adapted species and that length of leaf drip tips will be negatively correlated with photosynthetic capacity [characterized by light-saturated net photosynthetic rates (Amax), associated light compensation points (LCP), and light saturation points (LSP)]. We tested this hypothesis by measuring morphological and physiological traits that are associated with light-interception and water shedding for seven shade-adapted shrub species, ten sun-adapted understory shrub species, and 15 sun-adapted tree species in a subtropical Chinese rainforest, where mean annual precipitation is around 1,600 mm. Shade-adapted understory species had lower LMA, Amax, LSP, and LCP compared to understory or canopy sun-adapted species; their leaf and twig inclination angles were significantly smaller and leaf drip tips were significantly longer than those in sun-adapted species. This suggests that shade-adapted understory species tend to develop pronounced leaf drip tips but not large leaf inclination angles to shed water. The length of leaf drip tips was negatively correlated with leaf inclination angles and photosynthetic capacity. These relationships were consistent between ordinary regression and phylogenetic generalized least squares analyses. Our study illustrates the trade-offs between light interception and leaf water shedding and indicates that length of leaf drip tips can be used as an indicator of adaptation to shady conditions and overall photosynthetic performance of shrub species in subtropical rainforests.

Analysis of Radiation Transport Due to Activated Coolant in the ITER Neutral Beam Injection Cell

DOE Office of Scientific and Technical Information (OSTI.GOV)

Royston, Katherine; Wilson, Stephen C.; Risner, Joel M.

Detailed spatial distributions of the biological dose rate due to a variety of sources are required for the design of the ITER tokamak facility to ensure that all radiological zoning limits are met. During operation, water in the Integrated loop of Blanket, Edge-localized mode and vertical stabilization coils, and Divertor (IBED) cooling system will be activated by plasma neutrons and will flow out of the bioshield through a complex system of pipes and heat exchangers. This paper discusses the methods used to characterize the biological dose rate outside the tokamak complex due to 16N gamma radiation emitted by the activatedmore » coolant in the Neutral Beam Injection (NBI) cell of the tokamak building. Activated coolant will enter the NBI cell through the IBED Primary Heat Transfer System (PHTS), and the NBI PHTS will also become activated due to radiation streaming through the NBI system. To properly characterize these gamma sources, the production of 16N, the decay of 16N, and the flow of activated water through the coolant loops were modeled. The impact of conservative approximations on the solution was also examined. Once the source due to activated coolant was calculated, the resulting biological dose rate outside the north wall of the NBI cell was determined through the use of sophisticated variance reduction techniques. The AutomateD VAriaNce reducTion Generator (ADVANTG) software implements methods developed specifically to provide highly effective variance reduction for complex radiation transport simulations such as those encountered with ITER. Using ADVANTG with the Monte Carlo N-particle (MCNP) radiation transport code, radiation responses were calculated on a fine spatial mesh with a high degree of statistical accuracy. In conclusion, advanced visualization tools were also developed and used to determine pipe cell connectivity, to facilitate model checking, and to post-process the transport simulation results.« less

Analysis of Radiation Transport Due to Activated Coolant in the ITER Neutral Beam Injection Cell

DOE PAGES

Royston, Katherine; Wilson, Stephen C.; Risner, Joel M.; ...

2017-07-26

Detailed spatial distributions of the biological dose rate due to a variety of sources are required for the design of the ITER tokamak facility to ensure that all radiological zoning limits are met. During operation, water in the Integrated loop of Blanket, Edge-localized mode and vertical stabilization coils, and Divertor (IBED) cooling system will be activated by plasma neutrons and will flow out of the bioshield through a complex system of pipes and heat exchangers. This paper discusses the methods used to characterize the biological dose rate outside the tokamak complex due to 16N gamma radiation emitted by the activatedmore » coolant in the Neutral Beam Injection (NBI) cell of the tokamak building. Activated coolant will enter the NBI cell through the IBED Primary Heat Transfer System (PHTS), and the NBI PHTS will also become activated due to radiation streaming through the NBI system. To properly characterize these gamma sources, the production of 16N, the decay of 16N, and the flow of activated water through the coolant loops were modeled. The impact of conservative approximations on the solution was also examined. Once the source due to activated coolant was calculated, the resulting biological dose rate outside the north wall of the NBI cell was determined through the use of sophisticated variance reduction techniques. The AutomateD VAriaNce reducTion Generator (ADVANTG) software implements methods developed specifically to provide highly effective variance reduction for complex radiation transport simulations such as those encountered with ITER. Using ADVANTG with the Monte Carlo N-particle (MCNP) radiation transport code, radiation responses were calculated on a fine spatial mesh with a high degree of statistical accuracy. In conclusion, advanced visualization tools were also developed and used to determine pipe cell connectivity, to facilitate model checking, and to post-process the transport simulation results.« less

Simulation and experimental measurement of radon activity using a multichannel silicon-based radiation detector.

PubMed

Ozdemir, F B; Selcuk, A B; Ozkorucuklu, S; Alpat, A B; Ozdemir, T; Ӧzek, N

2018-05-01

In this study, high-precision radiation detector (HIPRAD), a new-generation semiconductor microstrip detector, was used for detecting radon (Rn-222) activity. The aim of this study was to detect radon (Rn-222) activity experimentally by measuring the energy of particles in this detector. Count-ADC channel, eta-charge, and dose-response values were experimentally obtained using HIPRAD. The radon simulation in the radiation detector was theoretically performed using the Geant4 software package. The obtained radioactive decay, energy generation, energy values, and efficiency values of the simulation were plotted using the root program. The new-generation radiation detector proved to have 95% reliability according to the obtained dose-response graphs. The experimental and simulation results were found to be compatible with each other and with the radon decays and literature studies. Copyright © 2018 Elsevier Ltd. All rights reserved.

Temporary microglia-depletion after cosmic radiation modifies phagocytic activity and prevents cognitive deficits.

PubMed

Krukowski, Karen; Feng, Xi; Paladini, Maria Serena; Chou, Austin; Sacramento, Kristen; Grue, Katherine; Riparip, Lara-Kirstie; Jones, Tamako; Campbell-Beachler, Mary; Nelson, Gregory; Rosi, Susanna

2018-05-18

Microglia are the main immune component in the brain that can regulate neuronal health and synapse function. Exposure to cosmic radiation can cause long-term cognitive impairments in rodent models thereby presenting potential obstacles for astronauts engaged in deep space travel. The mechanism/s for how cosmic radiation induces cognitive deficits are currently unknown. We find that temporary microglia depletion, one week after cosmic radiation, prevents the development of long-term memory deficits. Gene array profiling reveals that acute microglia depletion alters the late neuroinflammatory response to cosmic radiation. The repopulated microglia present a modified functional phenotype with reduced expression of scavenger receptors, lysosome membrane protein and complement receptor, all shown to be involved in microglia-synapses interaction. The lower phagocytic activity observed in the repopulated microglia is paralleled by improved synaptic protein expression. Our data provide mechanistic evidence for the role of microglia in the development of cognitive deficits after cosmic radiation exposure.

Activation of eNOS in endothelial cells exposed to ionizing radiation involves components of the DNA damage response pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nagane, Masaki; Yasui, Hironobu; Sakai, Yuri

2015-01-02

Highlights: • eNOS activity is increased in BAECs exposed to X-rays. • ATM is involved in this increased eNOS activity. • HSP90 modulates the radiation-induced activation of ATM and eNOS. - Abstract: In this study, the involvement of ataxia telangiectasia mutated (ATM) kinase and heat shock protein 90 (HSP90) in endothelial nitric oxide synthase (eNOS) activation was investigated in X-irradiated bovine aortic endothelial cells. The activity of nitric oxide synthase (NOS) and the phosphorylation of serine 1179 of eNOS (eNOS-Ser1179) were significantly increased in irradiated cells. The radiation-induced increases in NOS activity and eNOS-Ser1179 phosphorylation levels were significantly reduced bymore » treatment with either an ATM inhibitor (Ku-60019) or an HSP90 inhibitor (geldanamycin). Geldanamycin was furthermore found to suppress the radiation-induced phosphorylation of ATM-Ser1181. Our results indicate that the radiation-induced eNOS activation in bovine aortic endothelial cells is regulated by ATM and HSP90.« less

Effects of Pharmacological Inhibition and Genetic Deficiency of Plasminogen Activator Inhibitor-1 in Radiation-Induced Intestinal Injury

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abderrahmani, Rym; Francois, Agnes; Buard, Valerie

2009-07-01

Purpose: To investigate effects of plasminogen activator inhibitor 1 (PAI-1) genetic deficiency and pharmacological PAI-1 inhibition with PAI-039 in a mouse model of radiation-induced enteropathy. Methods and Materials: Wild-type (Wt) and PAI-1{sup -/-} knockout mice received a single dose of 19 Gy to an exteriorized localized intestinal segment. Sham and irradiated Wt mice were treated orally with 1 mg/g of PAI-039. Histological modifications were quantified using a radiation injury score. Moreover, intestinal gene expression was monitored by real-time PCR. Results: At 3 days after irradiation, PAI-039 abolished the radiation-induced increase in the plasma active form of PAI-1 and limited themore » radiation-induced gene expression of transforming growth factor {beta}1 (TGF-{beta}1), CTGF, PAI-1, and COL1A2. Moreover, PAI-039 conferred temporary protection against early lethality. PAI-039 treatment limited the radiation-induced increase of CTGF and PAI-1 at 2 weeks after irradiation but had no effect at 6 weeks. Radiation injuries were less severe in PAI-1{sup -/-} mice than in Wt mice, and despite the beneficial effect, 3 days after irradiation, PAI-039 had no effects on microscopic radiation injuries compared to untreated Wt mice. Conclusions: A genetic deficiency of PAI-1 is associated with amelioration of late radiation enteropathy. Pharmacological inhibition of PAI-1 by PAI-039 positively impacts the early, acute phase increase in plasma PAI-1 and the associated radiation-induced gene expression of inflammatory/extracellular matrix proteins. Since PAI-039 has been shown to inhibit the active form of PAI-1, as opposed to the complete loss of PAI-1 in the knockout animals, these data suggest that a PAI-1 inhibitor could be beneficial in treating radiation-induced tissue injury in acute settings where PAI-1 is elevated.« less

Cloud and Radiation Mission with Active and Passive Sensing from the Space Station

NASA Technical Reports Server (NTRS)

Spinhirne, James D.

1998-01-01

A cloud and aerosol radiative forcing and physical process study involving active laser and radar profiling with a combination of passive radiometric sounders and imagers would use the space station as an observation platform. The objectives are to observe the full three dimensional cloud and aerosol structure and the associated physical parameters leading to a complete measurement of radiation forcing processes. The instruments would include specialized radar and lidar for cloud and aerosol profiling, visible, infrared and microwave imaging radiometers with comprehensive channels for cloud and aerosol observation and specialized sounders. The low altitude,. available power and servicing capability of the space station are significant advantages for the active sensors and multiple passive instruments.

The potential of detecting intermediate-scale biomass and canopy interception in a coniferous forest using cosmic-ray neutron intensity measurements and neutron transport modeling

NASA Astrophysics Data System (ADS)

Andreasen, M.; Looms, M. C.; Bogena, H. R.; Desilets, D.; Zreda, M. G.; Sonnenborg, T. O.; Jensen, K. H.

2014-12-01

The water stored in the various compartments of the terrestrial ecosystem (in snow, canopy interception, soil and litter) controls the exchange of the water and energy between the land surface and the atmosphere. Therefore, measurements of the water stored within these pools are critical for the prediction of e.g. evapotranspiration and groundwater recharge. The detection of cosmic-ray neutron intensity is a novel non-invasive method for the quantification of continuous intermediate-scale soil moisture. The footprint of the cosmic-ray neutron probe is a hemisphere of a few hectometers and subsurface depths of 10-70 cm depending on wetness. The cosmic-ray neutron method offers measurements at a scale between the point-scale measurements and large-scale satellite retrievals. The cosmic-ray neutron intensity is inversely correlated to the hydrogen stored within the footprint. Overall soil moisture represents the largest pool of hydrogen and changes in the soil moisture clearly affect the cosmic-ray neutron signal. However, the neutron intensity is also sensitive to variations of hydrogen in snow, canopy interception and biomass offering the potential to determine water content in such pools from the signal. In this study we tested the potential of determining canopy interception and biomass using cosmic-ray neutron intensity measurements within the framework of the Danish Hydrologic Observatory (HOBE) and the Terrestrial Environmental Observatories (TERENO). Continuous measurements at the ground and the canopy level, along with profile measurements were conducted at towers at forest field sites. Field experiments, including shielding the cosmic-ray neutron probes with cadmium foil (to remove lower-energy neutrons) and measuring reference intensity rates at complete water saturated conditions (on the sea close to the HOBE site), were further conducted to obtain an increased understanding of the physics controlling the cosmic-ray neutron transport and the equipment used

Coherence properties of blackbody radiation and application to energy harvesting and imaging with nanoscale rectennas

NASA Astrophysics Data System (ADS)

Lerner, Peter B.; Cutler, Paul H.; Miskovsky, Nicholas M.

2015-01-01

Modern technology allows the fabrication of antennas with a characteristic size comparable to the electromagnetic wavelength in the optical region. This has led to the development of new technologies using nanoscale rectifying antennas (rectennas) for solar energy conversion and sensing of terahertz, infrared, and visible radiation. For example, a rectenna array can collect incident radiation from an emitting source and the resulting conversion efficiency and operating characteristics of the device will depend on the spatial and temporal coherence properties of the absorbed radiation. For solar radiation, the intercepted radiation by a micro- or nanoscale array of devices has a relatively narrow spatial and angular distribution. Using the Van Cittert-Zernike theorem, we show that the coherence length (or radius) of solar radiation on an antenna array is, or can be, tens of times larger than the characteristic wavelength of the solar spectrum, i.e., the thermal wavelength, λT=2πℏc/(kBT), which for T=5000 K is about 3 μm. Such an effect is advantageous, making possible the rectification of solar radiation with nanoscale rectenna arrays, whose size is commensurate with the coherence length. Furthermore, we examine the blackbody radiation emitted from an array of antennas at temperature T, which can be quasicoherent and lead to a modified self-image, analogous to the Talbot-Lau self-imaging process but with thermal rather than monochromatic radiation. The self-emitted thermal radiation may be important as a nondestructive means for quality control of the array.

Comparison of lighting activity and inner radiation belt particle fluxes perturbations

NASA Astrophysics Data System (ADS)

Martinez Calderon, C.; Bortnik, J.; Li, W.; Spence, H. E.; Rodger, C. J.

2016-12-01

Lightning discharges are known to inject whistlers into the inner magnetosphere over a wide range of latitudes around their source. When a discharge occurs, it radiates electromagnetic energy, some of which propagates in the whistler-mode wave through the ionospheric plasma travelling away from the Earth. Previous studies have discussed the effects of whistler-induced electron precipitation and radiation belt losses associated with lightning but there has been little research on the long term effects of these precipitation on the inner radiation belts [Rodger et al. (2004), Clilverd et al. (2004)].Here, we use data from the World Wide Lightning Location Network (WWLLN), which has continuously monitored global lightning since 2004, to examine one year of lightning data and locate the L-shells with high lighting activity. We use Van Allen Probes' Energetic Particle, Composition, and Thermal Plasma Suite (ECT) from both satellites (RBSP-A/B) to measure electron fluxes in the inner radiation belt at the L-shells of interest. We compare these fluxes to a globally-integrated count of lightning strikes and investigate the relationship between global lightning occurrence and RBSP electron fluxes. We examine several factors, such as different energy ranges, timescales ranging from a few weeks to the entire year and seasonal changes in order to quantify the loss process driven by lightning in the inner radiation belts.

Multifrequency dial sensing of the atmospheric gaseous constituents using the first and second harmonics of a tunable CO2 laser radiation

NASA Technical Reports Server (NTRS)

Zuev, V. E.; Andreev, Y. M.; Voevodin, V. G.; Gribenyukov, A. I.; Kapitanov, V. A.; Sosnin, A. V.; Stuchebrov, G. A.; Khmelnitskii, G. S.

1986-01-01

The results of field measurements of concentration of some gaseous components of the atmosphere along the paths, in Sofia, Bulgaria, using a gas analyzer based on the use of a CO2 laser radiation frequency-doubled with ZnGeP2 monocrystals are presented. The gas analyzer is a traditional long path absorption meter. Radiation from the tunable CO2 laser of low pressure and from an additional He-Ne laser is directed to a colliminating hundredfold Gregori telescope with a 300 mm diameter of the principal mirror. The dimensions of the mirrors of a retroreflector 500 x 500 mm and a receiving telescope allow one to totally intercept the beam passed through the atmospheric layer under study and back.

A survey of radiation treatment planning peer-review activities in a provincial radiation oncology programme: current practice and future directions

PubMed Central

Brundage, Michael; Foxcroft, Sophie; McGowan, Tom; Gutierrez, Eric; Sharpe, Michael; Warde, Padraig

2013-01-01

Objectives To describe current patterns of practice of radiation oncology peer review within a provincial cancer system, identifying barriers and facilitators to its use with the ultimate aim of process improvement. Design A survey of radiation oncology programmes at provincial cancer centres. Setting All cancer centres within the province of Ontario, Canada (n=14). These are community-based outpatient facilities overseen by Cancer Care Ontario, the provincial cancer agency. Participants A delegate from each radiation oncology programme filled out a single survey based on input from their multidisciplinary team. Outcome measures Rated importance of peer review; current utilisation; format of the peer-review process; organisation and timing; case attributes; outcomes of the peer-review process and perceived barriers and facilitators to expanding peer-review processes. Results 14 (100%) centres responded. All rated the importance of peer review as at least 8/10 (10=extremely important). Detection of medical error and improvement of planning processes were the highest rated perceived benefits of peer review (each median 9/10). Six centres (43%) reviewed at least 50% of curative cases; four of these centres (29%) conducted peer review in more than 80% of cases treated with curative intent. Fewer than 20% of cases treated with palliative intent were reviewed in most centres. Five centres (36%) reported usually conducting peer review prior to the initiation of treatment. Five centres (36%) recorded the outcomes of peer review on the medical record. Thirteen centres (93%) planned to expand peer-review activities; a critical mass of radiation oncologists was the most important limiting factor (median 6/10). Conclusions Radiation oncology peer-review practices can vary even within a cancer system with provincial oversight. The application of guidelines and standards for peer-review processes, and monitoring of implementation and outcomes, will require effective knowledge

Up-stream events in the nuclear factor κB activation cascade in response to sparsely ionizing radiation

NASA Astrophysics Data System (ADS)

Hellweg, Christine E.; Langen, Britta; Klimow, Galina; Ruscher, Roland; Schmitz, Claudia; Baumstark-Khan, Christa; Reitz, Günther

2009-10-01

Radiation is a potentially limiting factor for manned long-term space missions. Prolonged exposure to galactic cosmic rays may shorten the healthy life-span after return to Earth due to cancer induction. During the mission, a solar flare can be life threatening. For better risk estimation and development of appropriate countermeasures, the study of the cellular radiation response is necessary. Since apoptosis may be a mechanism the body uses to eliminate damaged cells, the induction by cosmic radiation of the nuclear anti-apoptotic transcription factor nuclear factor κB (NF-κB) could influence the cancer risk of astronauts exposed to cosmic radiation by improving the survival of radiation-damaged cells. In previous studies using a screening assay for the detection of NF-κB-dependent gene induction (HEK-pNF-κB-d2EGFP/Neo cells), the activation of this transcription factor by heavy ions was shown [Baumstark-Khan, C., Hellweg, C.E., Arenz, A., Meier, M.M. Cellular monitoring of the nuclear factor kappa B pathway for assessment of space environmental radiation. Radiat. Res. 164, 527-530, 2005]. Studies with NF-κB inhibitors can map functional details of the NF-κB pathway and the influence of radiation-induced NF-κB activation on various cellular outcomes such as survival or cell cycle arrest. In this work, the efficacy and cytotoxicity of four different NF-κB inhibitors, caffeic acid phenethyl ester (CAPE), capsaicin, the proteasome inhibitor MG-132, and the cell permeable peptide NF-κB SN50 were analyzed using HEK-pNF-κB-d2EGFP/Neo cells. In the recommended concentration range, only CAPE displayed considerable cytotoxicity. CAPE and capsaicin partially inhibited NF-κB activation by the cytokine tumor necrosis factor α. MG-132 completely abolished the activation and was therefore used for experiments with X-rays. NF-κB SN-50 could not reduce NF-κB dependent expression of the reporter destabilized Enhanced Green Fluorescent Protein (d2EGFP). MG-132

Hornet peak flight activity is correlated with solar UV radiation: a multi-annual survey.

PubMed

Ishay, Jacob S; Pertsis, Vitaly

2002-01-01

This study deals with the effect which solar irradiation of short wavelength, particularly ultraviolet (UV), exerts on the activities of hornets. The findings are based on multi-annual observations carried out during the years 1985, 1989 and 1998 on hornet nests in the field. At the peak of UV radiation, which occurs at noon, hornet activity is greater by 1-2 orders of magnitude than that during the morning or evening hours. The main visible hornet activity appears to be the removal of soil particles from the nest so as to enlarge its volume, enable the building of additional combs and also increase the size of existing combs. Hornet flight during peak insolation hours is characterized by its briefness (5-20 seconds only) and brevity (to distances of 5-10 meters only) as compared to flights at other hours of the day. These prolonged, multi-annual observations lead to the conclusion that hornets are capable of converting the energy of UV radiation into a form amenable to metabolic usage. In this respect the hornet cuticle behaves as a thermophotovoltaic device, i.e., a semiconductor diode that converts photons radiating from the sunlight into electrical energy.

Effects of UV-B radiation on photosynthesis activity of Wolffia arrhiza as probed by chlorophyll fluorescence transients

NASA Astrophysics Data System (ADS)

Wang, Gaohong; Hao, Zongjie; Anken, Ralf H.; Lu, Jinying; Liu, Yongding

2010-04-01

The higher plant Wolffia arrhiza is regarded to be well suited concerning the provision of photosynthetic products in the cycle of matter of a Controlled Ecological Life Support System (CELSS) to be established in the context of extraterrestrial, human-based colonization and long-term space flight. Since UV radiation is one major extraterrestrial environmental stress for growth of any plant, effects of UV-B radiation on W. arrhiza were assessed in the present study. We found that UV-B radiation significantly inhibited photosynthetic CO2 assimilation activity, and the contents of chlorophyll a, chlorophyll b (Chl a, Chl b) and carotenoids considerably decreased when plants were exposed to UV-B radiation for 12 h. High UV-B radiation also declined the quantum yield of primary photochemistry (φpo), the quantum yield for electron transport (φEo) and the efficiency per trapped excitation (Ψo) in W. arrhiza simultaneously, while the amount of active PSII reaction centers per excited cross section (RC/CS) and the total number of active reaction centers per absorption (RC/ABS) had comparative changes. These results indicate that the effects of UV-B radiation on photosynthesis of W. arrhiza is due to an inhibition of the electron transport and via inactivation of reaction centers, but the inhibition may take place at more than one site in the photosynthetic apparatus.

Ionizing radiation induces O6-alkylguanine-DNA-alkyltransferase mRNA and activity in mouse tissues.

PubMed

Wilson, R E; Hoey, B; Margison, G P

1993-04-01

The effect of exposure to whole-body gamma-irradiation or fast electrons on O6-alkylguanine-DNA-alkyltransferase (ATase) activity and mRNA abundance has been examined in mice. In response to gamma-radiation, hepatic ATase activity was significantly raised in BDF1 mice 24 h post-irradiation, reaching a maximum of 2- to 3-fold at 36 h and beginning to decrease by 48-60 h. A small but consistently higher level of induction was achieved when mice were exposed using a low dose rate (0.015 Gy/min) compared to a high dose rate (0.5 Gy/min). ATase activity was also induced approximately 2-fold 48 h post-irradiation in brain, kidney, lung and spleen, with a greater induction again observed in response to the lower dose rate. In response to fast electrons from a linear accelerator hepatic ATase activity was also induced 2- to 3-fold 48 h post-irradiation in BDF1, BALB/c, C57Bl and DBA2 strains. Induction of ATase activity in livers of BDF1 mice was observed 48 h after a total single dose of 5 Gy gamma-radiation (2-fold), increasing to a slightly higher level at 15 Gy, but no induction was observed at doses of 2 Gy and below. Although a maximum 2- to 3-fold induction of ATase activity was observed, mRNA levels were induced 3- to 4-fold by 48 h after a dose of 15 Gy. Furthermore, significant increases in mRNA levels were detected at low doses (1-2 Gy) at which there was no apparent increase in ATase activity. This suggests that ionizing radiation increases ATase levels by a process involving transcriptional upregulation but that strong post-transcriptional and/or translational controls operate to limit induction of enzyme activity to 2- to 3-fold. This is the first report of an in vivo induction of ATase by ionizing radiation in a species other than the rat.

Thermal Performance of Orion Active Thermal Control System With Seven-Panel Reduced-Curvature Radiator

NASA Technical Reports Server (NTRS)

Wang, Xiao-Yen J.; Yuko, James R.

2010-01-01

The active thermal control system (ATCS) of the crew exploration vehicle (Orion) uses radiator panels with fluid loops as the primary system to reject heat from spacecraft. The Lockheed Martin (LM) baseline Orion ATCS uses eight-panel radiator coated with silver Teflon coating (STC) for International Space Station (ISS) missions, and uses seven-panel radiator coated with AZ 93 white paint for lunar missions. As an option to increase the radiator area with minimal impact on other component locations and interfaces, the reduced-curvature (RC) radiator concept was introduced and investigated here for the thermal perspective. Each RC radiator panel has 15 percent more area than each Lockheed Martin (LM) baseline radiator panel. The objective was to determine if the RC seven-panel radiator concept could be used in the ATCS for both ISS and lunar missions. Three radiator configurations the LM baseline, an RC seven-panel radiator with STC, and an RC seven-panel radiator with AZ 93 coating were considered in the ATCS for ISS missions. Two radiator configurations the LM baseline and an RC seven-panel radiator with AZ 93 coating were considered in the ATCS for lunar missions. A Simulink/MATLAB model of the ATCS was used to compute the ATCS performance. Some major hot phases on the thermal timeline were selected because of concern about the large amount of water sublimated for thermal topping. It was concluded that an ATCS with an RC seven-panel radiator could be used for both ISS and lunar missions, but with two different coatings STC for ISS missions and AZ 93 for lunar missions to provide performance similar to or better than that of the LM baseline ATCS.

Exoatmospheric intercepts using zero effort miss steering for midcourse guidance

NASA Astrophysics Data System (ADS)

Newman, Brett

The suitability of proportional navigation, or an equivalent zero effort miss formulation, for exatmospheric intercepts during midcourse guidance, followed by a ballistic coast to the endgame, is addressed. The problem is formulated in terms of relative motion in a general, three dimensional framework. The proposed guidance law for the commanded thrust vector orientation consists of the sum of two terms: (1) along the line of sight unit direction and (2) along the zero effort miss component perpendicular to the line of sight and proportional to the miss itself and a guidance gain. If the guidance law is to be suitable for longer range targeting applications with significant ballistic coasting after burnout, determination of the zero effort miss must account for the different gravitational accelerations experienced by each vehicle. The proposed miss determination techniques employ approximations for the true differential gravity effect and thus, are less accurate than a direct numerical propagation of the governing equations, but more accurate than a baseline determination, which assumes equal accelerations for both vehicles. Approximations considered are constant, linear, quadratic, and linearized inverse square models. Theoretical results are applied to a numerical engagement scenario and the resulting performance is evaluated in terms of the miss distances determined from nonlinear simulation.

The responses of light interception, photosynthesis and fruit yield of cucumber to LED-lighting within the canopy.

PubMed

Trouwborst, Govert; Oosterkamp, Joke; Hogewoning, Sander W; Harbinson, Jeremy; van Ieperen, Wim

2010-03-01

Mathematical models of light attenuation and canopy photosynthesis suggest that crop photosynthesis increases by more uniform vertical irradiance within crops. This would result when a larger proportion of total irradiance is applied within canopies (interlighting) instead of from above (top lighting). These irradiance profiles can be generated by Light Emitting Diodes (LEDs). We investigated the effects of interlighting with LEDs on light interception, on vertical gradients of leaf photosynthetic characteristics and on crop production and development of a greenhouse-grown Cucumis sativus'Samona' crop and analysed the interaction between them. Plants were grown in a greenhouse under low natural irradiance (winter) with supplemental irradiance of 221 micromol photosynthetic photon flux m(-2) s(-1) (20 h per day). In the interlighting treatment, LEDs (80% Red, 20% Blue) supplied 38% of the supplemental irradiance within the canopy with 62% as top lighting by High-Pressure Sodium (HPS)-lamps. The control was 100% top lighting (HPS lamps). We measured horizontal and vertical light extinction as well as leaf photosynthetic characteristics at different leaf layers, and determined total plant production. Leaf mass per area and dry mass allocation to leaves were significantly greater but leaf appearance rate and plant length were smaller in the interlighting treatment. Although leaf photosynthetic characteristics were significantly increased in the lower leaf layers, interlighting did not increase total biomass or fruit production, partly because of a significantly reduced vertical and horizontal light interception caused by extreme leaf curling, likely because of the LED-light spectrum used, and partly because of the relatively low irradiances from above.

Influence of Extraterrestrial Radiation on Radiation Portal Monitors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keller, Paul E.; Kouzes, Richard T.

2009-06-01

Cosmic radiation and solar flares can be a major source of background radiation at the Earth’s surface. This paper examines the relationship between extraterrestrial radiation and the detectable background in radiation portal monitors used for homeland security applications. Background radiation data from 13 radiation portal monitor facilities are examined and compared against external sources of data related to extraterrestrial radiation, including measurements at neutron monitors located at 53 cosmic-ray observatories around the Earth, four polar orbiting satellites, three geostationary satellites, ground-based geomagnetic field data from observatories around the Earth, a solar magnetic index, solar radio flux data, and sunspot activitymore » data. Four-years (January 2003 through December 2006) of data are used in this study, which include the latter part of Solar Cycle 23 as solar activity was on the decline. The analysis shows a significant relationship between some extraterrestrial radiation and the background detected in the radiation portal monitors. A demonstrable decline is shown in the average gamma ray and neutron background at the radiation portal monitors as solar activity declined over the period of the study.« less

The role of obesity and physical activity in non-specific and radiating low back pain: the Young Finns study.

PubMed

Shiri, Rahman; Solovieva, Svetlana; Husgafvel-Pursiainen, Kirsti; Telama, Risto; Yang, Xiaolin; Viikari, Jorma; Raitakari, Olli T; Viikari-Juntura, Eira

2013-06-01

To study the effects of obesity, physical activity, and change in physical activity on the incidence of low back pain and explore whether obesity modifies the effects of physical activity. As part of the ongoing Young Finns Study, 1224 subjects aged 24-39 years free from low back pain during the preceding 12 months at baseline in 2001 were included. Obesity was defined based on the body mass index (BMI) and waist circumference, and physical activity was assessed by the metabolic equivalent of task (MET) index in 2001 and 2007. Abdominal obesity, defined by an increased waist circumference, was associated with an increased incidence of radiating low back pain (adjusted odds ratio (OR) = 1.7 and 95% confidence interval (CI) 1.1-2.7), while it had no effect on non-specific low back pain. BMI was associated neither with the incidence of radiating low back pain nor with non-specific low back pain. Compared with subjects who stayed active during follow-up, those with a low level of physical activity (adjusted OR = 2.0 and 95% CI 1.1-3.5) and active subjects who further increased their physical activity during follow-up (OR = 3.1 and 95% CI 1.5-6.7) had a higher incidence of radiating low back pain. Low level of physical activity was associated with an increased incidence of radiating low back pain in obese (OR = 3.3 and 95% 1.1-10.4), but not in non-overweight subjects (OR = 1.1 and 95% CI 0.6-1.9). Physical activity was not associated with non-specific low back pain. Our findings indicate that both obesity and low level of physical activity are independent risk factors of radiating low back pain. The current findings propose a U-shaped relation between physical activity and radiating low back pain. Moderate level of physical activity is recommended for the prevention of low back pain, especially in obese individuals. In all, our findings imply that obese individuals should stay physically active, even if they may not lose weight. Copyright © 2013 Elsevier Inc. All

From Assumption of Knowledge to Knowledgeable Considerations: a Class Activity on 'Ionizing Radiation' and Its Biological Effects.

ERIC Educational Resources Information Center

Ronen, Miky; Ganiel, Uri

1988-01-01

Describes a class activity, a game called "Beware--Radiation," developed as a framework for the introduction of the topic of radiation. Reports that both students and teachers had similar and mostly wrong preconceptions. (Author/YP)

Considering species richness and rarity when selecting optimal survey traps: comparison of semiochecmial baited flight intercept traps for Cerambycidae in eastern North America

Treesearch

Kevin J. Dodds; Jeremy D. Allison; Daniel R. Miller; Ryan P. Hanavan; Jon Sweeney

2015-01-01

1.) We compared standard multiple-funnel, modified multiple-funnel, intercept panel and canopy malaise (SLAM) traps with top and bottom collecting cups for their effectiveness (species richness, rarity, abundance) at capturing Cerambycidae in eastern North America. 2.) Experiments were conducted in New York, Louisiana, Massachusetts and Georgia in 2011 and 2012. A...

Consistent radiative transfer modeling of active and passive observations of precipitation

NASA Astrophysics Data System (ADS)

Adams, Ian

2016-04-01

Spaceborne platforms such as the Tropical Rainfall Measurement Mission (TRMM) and the Global Precipitation Measurement (GPM) mission exploit a combination of active and passive sensors to provide a greater understanding of the three-dimensional structure of precipitation. While "operationalized" retrieval algorithms require fast forward models, the ability to perform higher fidelity simulations is necessary in order to understand the physics of remote sensing problems by testing assumptions and developing parameterizations for the fast models. To ensure proper synergy between active and passive modeling, forward models must be consistent when modeling the responses of radars and radiometers. This work presents a self-consistent transfer model for simulating radar reflectivities and millimeter wave brightness temperatures for precipitating scenes. To accomplish this, we extended the Atmospheric Radiative Transfer Simulator (ARTS) version 2.3 to solve the radiative transfer equation for active sensors and multiple scattering conditions. Early versions of ARTS (1.1) included a passive Monte Carlo solver, and ARTS is capable of handling atmospheres of up to three dimensions with ellipsoidal planetary geometries. The modular nature of ARTS facilitates extensibility, and the well-developed ray-tracing tools are suited for implementation of Monte Carlo algorithms. Finally, since ARTS handles the full Stokes vector, co- and cross-polarized reflectivity products are possible for scenarios that include nonspherical particles, with or without preferential alignment. The accuracy of the forward model will be demonstrated with precipitation events observed by TRMM and GPM, and the effects of multiple scattering will be detailed. The three-dimensional nature of the radiative transfer model will be useful for understanding the effects of nonuniform beamfill and multiple scattering for spatially heterogeneous precipitation events. The targets of this forward model are GPM (the

Effect of 99 GHz continuous millimeter wave electro-magnetic radiation on E. coli viability and metabolic activity.

PubMed

Cohen, Irena; Cahan, Rivka; Shani, Gad; Cohen, Eyal; Abramovich, Amir

2010-05-01

To investigate time exposure dependence of continuous millimeter wave (CW) 99 GHz radiation on Escherichia coli bacterial cell viability and metabolic activity. Suspensions of E. coli bacterial cells with an optical density of OD(660 nm) = 0.1 were used for viability tests and OD(660 nm) = 1.0 for metabolic activity tests. These suspensions were exposed to 99 GHz CW electromagnetic radiation, generated by a Backward Wave Oscillator (BWO) tube base instrument with a horn antenna at the BWO exit, to obtain an almost ideal Gaussian beam. Calculations of the Gaussian beam show that a power of 0.2 mW/cm(2) was obtained at the bacterial plane. The experimental results show that 1 hour of exposure to 99 GHz CW electromagnetic radiation had no effect on E. coli viability and colony characterisation. In 19 h of radiation, the number of colonies forming units was half order of magnitude higher than the sham-exposed and the control. However, 19 h of exposure did not affect the E. coli metabolic activity. Exposure of E. coli to millimeter wave (MW) CW 99 GHz radiation for a short period did not affect the viability of E. coli bacterial cells. However, exposure for 19 h caused a slight proliferation but did not influence the metabolic activities of about 90 biochemical reactions that were examined. Hence, we assume that the slight proliferation (half order of magnitude) after 19 h of exposure dose not have a biological meaning.

Neutron radiation tolerance of Au-activated silicon

NASA Technical Reports Server (NTRS)

Joyner, W. T.

1987-01-01

Double injection devices prepared by the introduction of deep traps, using the Au activation method have been found to tolerate gamma irradiation into the Gigarad (Si) region without significant degradation of operating characteristics. Silicon double injection devices, using deep levels creacted by Au diffusion, can tolerate fast neutron irradiation up to 10 to the 15th n/sq cm. Significant parameter degradation occurs at 10 to the 16th n/sq cm. However, since the actual doping of the basic material begins to change as a result of the transmutation of silicon into phosphorus for neutron fluences greater than 10 to the 17th/sq cm, the radiation tolerance of these devices is approaching the limit possible for any device based on initially doped silicon.

First-Episode Psychosis and the Criminal Justice System: Using a Sequential Intercept Framework to Highlight Risks and Opportunities.

PubMed

Wasser, Tobias; Pollard, Jessica; Fisk, Deborah; Srihari, Vinod

2017-10-01

In first-episode psychosis there is a heightened risk of aggression and subsequent criminal justice involvement. This column reviews the evidence pointing to these heightened risks and highlights opportunities, using a sequential intercept model, for collaboration between mental health services and existing diversionary programs, particularly for patients whose behavior has already brought them to the attention of the criminal justice system. Coordinating efforts in these areas across criminal justice and clinical spheres can decrease the caseload burden on the criminal justice system and optimize clinical and legal outcomes for this population.

CERTAIN SPECIFIC FEATURES OF THE HIGHER NERVOUS ACTIVITY OF FULLY GROWN ANIMALS IRRADIATED ANTENATALLY WITH IONIZING RADIATION. I. THE INFLUENCE OF IONIZING RADIATION ON THE OFFSPRING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Piontkovskii, I.A.

1958-09-01

Irradiation of pregnant female aniamals and women with ionizing radiation may cause the appearance of a variety of congenital deformities in the offspring and may interfere with their postnatal development. L. Hicks points out the particular sensitivity of the nervous system of the embryo to ionizing radiation. Thus irradiation of rats on the 9th, 11th, 12th, and 13th days of prenatal development may cause, in addition to somatic deformities, anencephaly (on the 9th day), hydrocephaly (on the 11th day), microcephaly (on the 12th13th day), failure of development of the subcortical structures, the corpora callosa and so on. The influence ofmore » ionizing radiation on the nervous system during antenatal irradiation has been studied mainly morphologically. There are no indications in the literature of the state of the higher nervous activity of fully grown animals exposed at various periods of their antenatal development to the action of ionizing radiation. The effect of ionizing radiation, applied in various doses and at different stages of embryonic development, on the state of the higher nervous activity of animals was studied. (auth)« less

Recovery and Stability of Δ9-Tetrahydrocannabinol Using the Oral-Eze® Oral Fluid Collection System and Intercept® Oral Specimen Collection Device.

PubMed

Samano, Kimberly L; Anne, Lakshmi; Johnson, Ted; Tang, Kenneth; Sample, R H Barry

2015-10-01

Oral fluid (OF) is increasingly used for clinical, forensic and workplace drug testing as an alternative to urine. Uncertainties surrounding OF collection device performance, drug stability and testing reproducibility may be partially responsible for delays in the implementation of OF testing in regulated drug testing programs. Stability of Δ(9)-tetrahydrocannabinol (THC) fortified and authentic specimens was examined after routine collection, transport and laboratory testing. Acceptable recovery and stability were observed when THC-fortified OF (1.5 and 4.5 ng/mL) was applied to Oral-Eze devices. Neat OF samples collected with Oral-Eze, processed per the package insert, and fortified with THC (3 and 6 ng/mL) were stable (±20%) at room temperature (21-25°C), refrigerated (2-8°C) and frozen (-25 to -15°C) conditions up to 1 month, while samples collected with Intercept devices showed decreases at refrigerated and room temperatures. After long-term refrigerated or frozen storage, maximum reductions in THC concentrations were 42% for Oral-Eze and 69% for Intercept. After ≥1 year frozen storage, 80.7% of laboratory specimens positive for THC (3 ng/mL cut-off) by GC-MS were reconfirmed positive (within 25%), with an average THC decrease of 4.2%. Specimens (n = 47) processed with Oral-Eze (diluted) and tested via enzyme immunoassay were concordant with LC-MS-MS results and showed 100% sensitivity and 95% specificity. Paired specimens collected with Oral-Eze and Intercept exhibited 98% overall agreement between the immunoassay test systems. Collectively, these data demonstrate consistent and reproducible recovery and stability of THC in OF after collection, transport and laboratory testing using the Oral-Eze OF Collection System. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Recruiting Hard-to-Reach Populations for Survey Research: Using Facebook and Instagram Advertisements and In-Person Intercept in LGBT Bars and Nightclubs to Recruit LGBT Young Adults.

PubMed

Guillory, Jamie; Wiant, Kristine F; Farrelly, Matthew; Fiacco, Leah; Alam, Ishrat; Hoffman, Leah; Crankshaw, Erik; Delahanty, Janine; Alexander, Tesfa N

2018-06-18

Tobacco public education campaigns focus increasingly on hard-to-reach populations at higher risk for smoking, prompting campaign creators and evaluators to develop strategies to reach hard-to-reach populations in virtual and physical spaces where they spend time. The aim of this study was to describe two novel recruitment strategies (in-person intercept interviews in lesbian, gay, bisexual, and transgender [LGBT] social venues and targeted social media ads) and compares characteristics of participants recruited via these strategies for the US Food and Drug Administration's This Free Life campaign evaluation targeting LGBT young adults who smoke cigarettes occasionally. We recruited LGBT adults aged 18-24 years in the United States via Facebook and Instagram ads (N=1709, mean age 20.94, SD 1.94) or intercept in LGBT social venues (N=2348, mean age 21.98, SD 1.69) for the baseline evaluation survey. Covariates related to recruitment strategy were age; race or ethnicity; LGBT identity; education; pride event attendance; and alcohol, cigarette, and social media use. Lesbian or gay women (adjusted odds ratio, AOR 1.88, 95% CI 1.54-2.29, P<.001), bisexual men and women (AOR 1.46, 95% CI 1.17-1.82, P=.001), gender minorities (AOR 1.68, 95% CI 1.26-2.25, P<.001), and other sexual minorities (AOR 2.48, 95% CI 1.62-3.80, P<.001) were more likely than gay men to be recruited via social media (than intercept). Hispanic (AOR 0.73, 95% CI 0.61-0.89, P=.001) and other or multiracial, non-Hispanic participants (AOR 0.70, 95% CI 0.54-0.90, P=.006) were less likely than white, non-Hispanic participants to be recruited via social media. As age increased, odds of recruitment via social media decreased (AOR 0.76, 95% CI 0.72-0.80, P<.001). Participants with some college education (AOR 1.27, 95% CI 1.03-1.56, P=.03) were more likely than those with a college degree to be recruited via social media. Participants reporting past 30-day alcohol use were less likely to be recruited via

Evaluating potential chlorinated methanes degradation mechanisms and treatments in interception trenches filled with concrete-based construction wastes

NASA Astrophysics Data System (ADS)

Rodríguez-Fernandez, Diana; Torrentó, Clara; Rosell, Mònica; Audí-Miró, Carme; Soler, Albert

2014-05-01

A complex mixture of chlorinated organic compounds is located in an unconfined carbonated bedrock aquifer with low permeability in a former industrial area next to Barcelona (NE Spain). The site exhibited an especially high complexity due to the presence of multiple contaminant sources, wide variety of pollutants (mainly chlorinated ethenes but also chlorinated methanes) and unknown system of fractures (Palau et al., 2014). Interception trenches were installed in the place of the removed pollution sources and were filled with construction wastes with the aim of retaining and treating the accumulated contaminated recharge water before reaching the aquifer. Recycled concrete-based aggregates from a construction and demolition waste recycling plant were used to maintain alkaline conditions in the water accumulated in the trenches (pH 11.6±0.3) and thus induce chloroform (CF) degradation by alkaline hydrolysis. An efficacy of around 30-40% CF degradation in the interception trenches was calculated from the significant and reproducible CF carbon isotopic fractionation (-53±3o obtained in batch experiments (Torrentó et al., 2014). Surprisingly, although hydrolysis of carbon tetrachloride (CT) is extremely slow, a significant CT carbon isotopic enrichment was also observed in the trenches. The laboratory experiments verified the low capability of concrete to hydrolyze the CT and showed the high adsorption of CT on the concrete particles (73% after 50 days) with invariability in its δ13C values. Therefore, the significant CT isotopic fractionation observed in the interception trenches could point out the occurrence of other degradation processes distinct than alkaline hydrolysis. Geochemical speciation modelling using the code PHREEQC showed that water collected at the trenches is supersaturated with respect to several iron oxy-hydroxides and therefore, CT degradation processes related to these iron minerals cannot be discarded. In addition, the combination of alkaline

Radiation damage caused by cold neutrons in boron doped CMOS active pixel sensors

NASA Astrophysics Data System (ADS)

Linnik, B.; Bus, T.; Deveaux, M.; Doering, D.; Kudejova, P.; Wagner, F. M.; Yazgili, A.; Stroth, J.

2017-05-01

CMOS Monolithic Active Pixel Sensors (MAPS) are considered as an emerging technology in the field of charged particle tracking. They will be used in the vertex detectors of experiments like STAR, CBM and ALICE and are considered for the ILC and the tracker of ATLAS. In those applications, the sensors are exposed to sizeable radiation doses. While the tolerance of MAPS to ionizing radiation and fast hadrons is well known, the damage caused by low energy neutrons was not studied so far. Those slow neutrons may initiate nuclear fission of 10B dopants found in the B-doped silicon active medium of MAPS. This effect was expected to create an unknown amount of radiation damage beyond the predictions of the NIEL (Non Ionizing Energy Loss) model for pure silicon. We estimate the impact of this effect by calculating the additional NIEL created by this fission. Moreover, we show first measured data for CMOS sensors which were irradiated with cold neutrons. The empirical results contradict the prediction of the updated NIEL model both, qualitatively and quantitatively: the sensors irradiated with slow neutrons show an unexpected and strong acceptor removal, which is not observed in sensors irradiated with MeV neutrons.

Spectral properties of plant leaves pertaining to urban landscape design of broad-spectrum solar ultraviolet radiation reduction

NASA Astrophysics Data System (ADS)

Yoshimura, Haruka; Zhu, Hui; Wu, Yunying; Ma, Ruijun

2010-03-01

Human exposure to harmful ultraviolet (UV) radiation has important public health implications. Actual human exposure to solar UV radiation depends on ambient UV irradiance, and the latter is influenced by ground reflection. In urban areas with higher reflectivity, UV exposure occurs routinely. To discover the solar UV radiation regulation mechanism of vegetation, the spectral reflectance and transmittance of plant leaves were measured with a spectrophotometer. Typically, higher plants have low leaf reflectance (around 5%) and essentially zero transmittance throughout the UV region regardless of plant species and seasonal change. Accordingly, incident UV radiation decreases to 5% by being reflected and is reduced to zero by passing through a leaf. Therefore, stratified structures of vegetation are working as another terminator of UV rays, protecting whole terrestrial ecosystems, while vegetation at waterfronts contributes to protect aquatic ecosystems. It is possible to protect the human population from harmful UV radiation by urban landscape design of tree shade and the botanical environment. Even thin but uniformly distributed canopy is effective in attenuating UV radiation. To intercept diffuse radiation, UV screening by vertical structures such as hedges should be considered. Reflectivity of vegetation is around 2%, as foliage surfaces reduce incident UV radiation via reflection, while also eliminating it by transmittance. Accordingly, vegetation reduces incident UV radiation to around 2% by reflection. Vegetation influence on ambient UV radiation is broad-spectrum throughout the UV region. Only trees provide cool UV protective shade. Urban landscapes aimed at abating urban heat islands integrated with a reduction of human UV over-exposure would contribute to mitigation of climate change.

Relative Performance of Lindgren Multiple-Funnel, Intercept Panel, and Colossus Pipe Traps in Catching Cerambycidae and Associated Species in the Southeastern United States

Treesearch

Daniel R. Miller; Christopher M. Crowe

2011-01-01

In 2004, we evaluated the relative performance of 8-unit Lindgren multiple-funnel (funnel), Intercept panel (panel), and Colossus pipe (pipe) traps, baited with ethanol and -pinene lures, in catching saproxylic beetles (Coleoptera) in pine stands in northern Florida and western South Carolina. Panel traps were as good as, if not better than, funnel and pipe...

[Variations of solar activity and radiation situation on board MIR station during the period 1986-1994].

PubMed

Bondarenko, V A; Mitrikas, V G; Tsetlin , V V

1995-01-01

This paper is dedicated to the analysis of the radiation situation onboard Mir station over a period of 1986-1994, there examined the main cosmophysics parameters and indices of the solar activity as well as the variations of the parameters of the earth's magnetic field and their association with the changes in the power of absorbed dose onboard the station. There noted the high levels of radiation exposure to the cosmonauts under terrestrial conditions when carrying out the roentgeno-radiologic examinations and procedures comparable or exceeding the absorbed doses during the flights. For revealing the regular associations of the radiation situation onboard the station with the parameters of solar activity there has been analyzed the time changes of average monthly values of dose power since the beginning of station functioning in 1986 until returning the fifteenth expedition to Earth. From the analyses of the results it might be assumed that the best statistical associations of average monthly power of the absorbed dose are found with the streams of protons of GCR. Wolff numbers and background stream of the radio emission of the Sun which reflects the existence of the radiation situation upon the phase of solar activity cycle. From this paper it transpires that calculating the dose loads during the period of the extreme phases of solar activity, it is possible to make between them the interpolations of time dependence by analogy with the dynamics in time of the background streams of GCR or Wolff numbers.

Absorbed photosynthetically active radiation of steppe vegetation and sun-view geometry effects on APAR estimates

NASA Technical Reports Server (NTRS)

Walter-Shea, E. A.; Blad, B. L.; Mesarch, M. A.; Hays, C. J.; Deering, D. W.; Eck, T. F.

1992-01-01

Instantaneous fractions of absorbed photosynthetically active radiation (APAR) were measured at the Streletskaya Steppe Reserve in conjunction with canopy bidirectional-reflected radiation measured at solar zenith angles ranging between 37 and 74 deg during the Kursk experiment (KUREX-91). APAR values were higher for KUREX-91 than those for the first ISLSCP field experiment (FIFE-89) and the amount of APAR of a canopy was a function of solar zenith angle, decreasing as solar zenith angle increased at the resrve. Differences in absorption are attributed to leaf area index (LAI) and leaf angle distribution and subsequently transmitted radiation interactions. LAIs were considerably higher at the reserve than those at the FIFE site. Leaf angle distributions of the reserve approach a uniform distribution while distributions at the FIFE site more closely approximate erectophile distributions. Reflected photosynthetically active radiation (PAR) components at KUREX-91 and FIFE-89 were similar in magnitude and in their response to solar zenith angle. Transmitted PAR increased with increasing solar zenith angle at KUREX-91 and decreased with increasing solar zenith angle at FIFE-89. Transmitted PAR at FIFE-89 was considerably larger than those at KUREX-91.

Tree Canopy Light Interception Estimates in Almond and a Walnut Orchards Using Ground, Low Flying Aircraft, and Satellite Based Methods to Improve Irrigation Scheduling Programs

NASA Technical Reports Server (NTRS)

Rosecrance, Richard C.; Johnson, Lee; Soderstrom, Dominic

2016-01-01

Canopy light interception is a main driver of water use and crop yield in almond and walnut production. Fractional green canopy cover (Fc) is a good indicator of light interception and can be estimated remotely from satellite using the normalized difference vegetation index (NDVI) data. Satellite-based Fc estimates could be used to inform crop evapotranspiration models, and hence support improvements in irrigation evaluation and management capabilities. Satellite estimates of Fc in almond and walnut orchards, however, need to be verified before incorporating them into irrigation scheduling or other crop water management programs. In this study, Landsat-based NDVI and Fc from NASA's Satellite Irrigation Management Support (SIMS) were compared with four estimates of canopy cover: 1. light bar measurement, 2. in-situ and image-based dimensional tree-crown analyses, 3. high-resolution NDVI data from low flying aircraft, and 4. orchard photos obtained via Google Earth and processed by an Image J thresholding routine. Correlations between the various estimates are discussed.

Tree canopy light interception estimates in almond and a walnut orchards using ground, low flying aircraft, and satellite based methods to improve irrigation scheduling programs.

NASA Astrophysics Data System (ADS)

Rosecrance, R. C.; Johnson, L.; Soderstrom, D.

2016-12-01

Canopy light interception is a main driver of water use and crop yield in almond and walnut production. Fractional green canopy cover (Fc) is a good indicator of light interception and can be estimated remotely from satellite using the normalized difference vegetation index (NDVI) data. Satellite-based Fc estimates could be used to inform crop evapotranspiration models, and hence support improvements in irrigation evaluation and management capabilities. Satellite estimates of Fc in almond and walnut orchards, however, need to be verified before incorporating them into irrigation scheduling or other crop water management programs. In this study, Landsat-based NDVI and Fc from NASA's Satellite Irrigation Management Support (SIMS) were compared with four estimates of canopy cover: 1. light bar measurement, 2. in-situ and image-based dimensional tree-crown analyses, 3. high-resolution NDVI data from low flying aircraft, and 4. orchard photos obtained via Google Earth and processed by an Image J thresholding routine. Correlations between the various estimates are discussed.

Darcy-Forchheimer flow of Maxwell nanofluid flow with nonlinear thermal radiation and activation energy

NASA Astrophysics Data System (ADS)

Sajid, T.; Sagheer, M.; Hussain, S.; Bilal, M.

2018-03-01

The present article is about the study of Darcy-Forchheimer flow of Maxwell nanofluid over a linear stretching surface. Effects like variable thermal conductivity, activation energy, nonlinear thermal radiation is also incorporated for the analysis of heat and mass transfer. The governing nonlinear partial differential equations (PDEs) with convective boundary conditions are first converted into the nonlinear ordinary differential equations (ODEs) with the help of similarity transformation, and then the resulting nonlinear ODEs are solved with the help of shooting method and MATLAB built-in bvp4c solver. The impact of different physical parameters like Brownian motion, thermophoresis parameter, Reynolds number, magnetic parameter, nonlinear radiative heat flux, Prandtl number, Lewis number, reaction rate constant, activation energy and Biot number on Nusselt number, velocity, temperature and concentration profile has been discussed. It is viewed that both thermophoresis parameter and activation energy parameter has ascending effect on the concentration profile.

Physical activity in Georgia state parks: A pilot study

Treesearch

Lincoln R. Larson; Jason W. Whiting; Gary T. Green

2012-01-01

This pilot study assessed the role of Georgia State Parks in the promotion of physical activity among different racial/ethnic and age groups. Data were collected at three state parks in north Georgia during the summer of 2009 using two research methods: behavior observations (N=2281) and intercept surveys (N=473).

Radiation thermometry at NIST: An update of services and research activities

NASA Technical Reports Server (NTRS)

Hillard, G. Barry

1989-01-01

An overview of activities at the National Institute of Standards and Terminology (NIST) in radiation thermometry and related temperature scale research is presented. An expansion of calibration services for pyrometers will be described as well as efforts to develop calibration services for blackbody simulators. Research relevant to the realization of the new international temperature scale (ITS 90) will be discussed.

Food-purchasing patterns for home: a grocery store-intercept survey.

PubMed

Yoo, Sunmi; Baranowski, Tom; Missaghian, Mariam; Baranowski, Janice; Cullen, Karen; Fisher, Jennifer O; Watson, Kathy; Zakeri, Issa F; Nicklas, Theresa

2006-05-01

To identify the most common frequency of food-purchasing patterns and relate this pattern to characteristics of individuals and families. A customer-intercept survey was conducted in the greater Houston area, Texas, USA, in 2002. The frequency of food shopping at supermarkets, convenience stores and restaurants to buy food for eating at home was assessed. A total of 823 adults (78.5% female; mean age 37.4 years) who went to any of several grocery or convenience stores, including European, Hispanic and African Americans, and Asian/Pacific Islanders. Major food-shopping patterns were a weekly big trip with a few small trips (34.9%), biweekly big trips with a few small trips (21.9%), no big shopping trips (15.4%), a weekly big trip without small trips (13.9%), a monthly big trip (8.3%), and biweekly big trips without small trips (6.4%). While 61.1% of participants never went to convenience stores to buy fruit and vegetables (F&V) for eating at home, 67% went to restaurants for F&V. African American families shopped for food least frequently, while Asian American families shopped for food most frequently. Educational level was negatively associated with the use of convenience stores and positively associated with take-away from restaurants. There is substantial variability in the frequency of food shopping. Future research on food shopping should incorporate this variable.

Radiation tolerant passive and active optical fiber products for use in space environments

NASA Astrophysics Data System (ADS)

Hill, Mark; Hankey, Judith; Gray, Rebecca

2017-11-01

This paper reports the radiation performance results of several new product types designed for high radiation environments. The products tested include radiation hardened highly birefringent (HiBi) passive products for polarised applications and radiation tolerant active erbium doped fiber products for amplifiers. Radiation hardened, short beatlength HiBi fiber products have been developed for high accuracy polarisation maintaining (PM) gyros and sensors at both 1310nm and 1550nm operation in the space environment. The fibers have been tested up to 5kGy (500krad) - levels which could be expected in extreme, extra-terrestrial space environments. Results show a consistently low Radiation Induced Attenuation (RIA) of <7dB/km at 5kGy, giving a RIA value of 1.37×10-2 dB/km/krad at 1550nm for this product range. Radiation tolerant EDF AstroGain™ fibers are intended for use in multichannel amplifiers in optical intersatellite communications. The structure of the fibers have been designed to deliver an accelerated recovery of radiation damage through photo-annealing using only the residual energy already available in an amplifier using a 980nm pumping regime. These products have been tested up to 200Gy (20krad) - levels which can be expected in Earth orbit environments over a 20-30 mission lifetime. Results show up to 100% recovery under continuous use for dose rates of 0.11rad/hr. It has also been demonstrated through analysis of the optical spectral output that this effect reverses the gain tilt, or spectral narrowing, induced by radiation damage through the C and L band. These combined fiber characteristics allow performance stability of the amplifier over the lifetime of the space mission.

Extinction cross-section cancellation of a cylindrical radiating active source near a rigid corner and acoustic invisibility

NASA Astrophysics Data System (ADS)

Mitri, F. G.

2017-11-01

Active cloaking in its basic form requires that the extinction cross-section (or energy efficiency) from a radiating body vanishes. In this analysis, this physical effect is demonstrated for an active cylindrically radiating acoustic source in a non-viscous fluid, undergoing periodic axisymmetric harmonic vibrations near a rigid corner (i.e., quarter-space). The rigorous multipole expansion method in cylindrical coordinates, the method of images, and the addition theorem of cylindrical wave functions are used to derive closed-form mathematical expressions for the radiating, amplification, and extinction cross-sections of the active source. Numerical computations are performed assuming monopole and dipole modal oscillations of the circular source. The results reveal some of the situations where the extinction energy efficiency factor of the active source vanishes depending on its size and location with respect to the rigid corner, thus, achieving total invisibility. Moreover, the extinction energy efficiency factor varies between positive or negative values. These effects also occur for higher-order modal oscillations of the active source. The results find potential applications in the development of acoustic cloaking devices and invisibility in underwater acoustics or other areas.

Gaze Behavior in One-Handed Catching and Its Relation with Interceptive Performance: What the Eyes Can't Tell

PubMed Central

Cesqui, Benedetta; Mezzetti, Maura; Lacquaniti, Francesco; d'Avella, Andrea

2015-01-01

In ball sports, it is usually acknowledged that expert athletes track the ball more accurately than novices. However, there is also evidence that keeping the eyes on the ball is not always necessary for interception. Here we aimed at gaining new insights on the extent to which ocular pursuit performance is related to catching performance. To this end, we analyzed eye and head movements of nine subjects catching a ball projected by an actuated launching apparatus. Four different ball flight durations and two different ball arrival heights were tested and the quality of ocular pursuit was characterized by means of several timing and accuracy parameters. Catching performance differed across subjects and depended on ball flight characteristics. All subjects showed a similar sequence of eye movement events and a similar modulation of the timing of these events in relation to the characteristics of the ball trajectory. On a trial-by-trial basis there was a significant relationship only between pursuit duration and catching performance, confirming that keeping the eyes on the ball longer increases catching success probability. Ocular pursuit parameters values and their dependence on flight conditions as well as the eye and head contributions to gaze shift differed across subjects. However, the observed average individual ocular behavior and the eye-head coordination patterns were not directly related to the individual catching performance. These results suggest that several oculomotor strategies may be used to gather information on ball motion, and that factors unrelated to eye movements may underlie the observed differences in interceptive performance. PMID:25793989

Interceptive orthopedics for the correction of maxillary transverse and sagittal deficiency in the early mixed dentition period

PubMed Central

Talapaneni, Ashok Kumar; Kumar, Karnati Praveen; Kommi, Pradeep Babu; Nuvvula, Sivakumar

2011-01-01

Dentofacial Orthopedics directed to a hypoplastic maxilla in the prepubertal period redirects growth of the maxilla in the vertical, transverse and sagittal planes of space. The orthopedic correction of maxillary hypoplasia in the early mixed dentition period thus intercepts the establishment of permanent structural asymmetry in the mandible and helps in the achievement of optimal dentofacial esthetics. This paper presents the growth redirection in a hypoplastic maxilla of an 8-year-old girl with simultaneous rapid maxillary expansion and protraction headgear therapy for a period of 11 months which corrected the posterior unilateral cross-bite, the positional asymmetry of the mandible and established an orthognathic profile in the individual. PMID:22346162

Interception loss, throughfall and stemflow in a maritime pine stand. I. Variability of throughfall and stemflow beneath the pine canopy

NASA Astrophysics Data System (ADS)

Loustau, D.; Berbigier, P.; Granier, A.; Moussa, F. El Hadj

1992-10-01

Patterns of spatial variability of throughfall and stemflow were determined in a maritime pine ( Pinus pinaster Ait.) stand for two consecutive years. Data were obtained from 52 fixed rain gauges and 12 stemflow measuring devices located in a 50m × 50m plot at the centre of an 18-year-old stand. The pine trees had been sown in rows 4m apart and had reached an average height of 12.6m. The spatial distribution of stems had a negligible effect on the throughfall partitioning beneath the canopy. Variograms of throughfall computed for a sample of storms did not reveal any spatial autocorrelation of throughfall for the sampling design used. Differences in throughfall, in relation to the distance from the rows, were not consistently significant. In addition, the distance from the tree stem did not influence the amount of throughfall. The confidence interval on the amount of throughfall per storm was between 3 and 8%. The stemflow was highly variable between trees. The effect of individual trees on stemflow was significant but the amount of stemflow per tree was not related to tree size (i.e. height, trunk diameter, etc.). The cumulative sampling errors on stemflow and throughfall for a single storm created a confidence interval of between ±7 and ±51% on interception. This resulted mainly from the low interception rate and sampling error on throughfall.

Structural-electrical coupling optimisation for radiating and scattering performances of active phased array antenna

NASA Astrophysics Data System (ADS)

Wang, Congsi; Wang, Yan; Wang, Zhihai; Wang, Meng; Yuan, Shuai; Wang, Weifeng

2018-04-01

It is well known that calculating and reducing of radar cross section (RCS) of the active phased array antenna (APAA) are both difficult and complicated. It remains unresolved to balance the performance of the radiating and scattering when the RCS is reduced. Therefore, this paper develops a structure and scattering array factor coupling model of APAA based on the phase errors of radiated elements generated by structural distortion and installation error of the array. To obtain the optimal radiating and scattering performance, an integrated optimisation model is built to optimise the installation height of all the radiated elements in normal direction of the array, in which the particle swarm optimisation method is adopted and the gain loss and scattering array factor are selected as the fitness function. The simulation indicates that the proposed coupling model and integrated optimisation method can effectively decrease the RCS and that the necessary radiating performance can be simultaneously guaranteed, which demonstrate an important application value in engineering design and structural evaluation of APAA.

IAEA activities related to radiation biology and health effects of radiation.

PubMed

Wondergem, Jan; Rosenblatt, Eduardo

2012-03-01

The IAEA is involved in capacity building with regard to the radiobiological sciences in its member states through its technical cooperation programme. Research projects/programmes are normally carried out within the framework of coordinated research projects (CRPs). Under this programme, two CRPs have been approved which are relevant to nuclear/radiation accidents: (1) stem cell therapeutics to modify radiation-induced damage to normal tissue, and (2) strengthening biological dosimetry in IAEA member states.

[Effects of nitrogen application rate on light interception and dry matter distribution at diffe-rent layers in wheat canopy under supplemental irrigation based on measuring soil moisture.

PubMed

Zheng, Xue Jiao; Yu, Zhen Wen; Zhang, Yong Li; Shi, Yu

2018-02-01

With the large-spike wheat cultivar Shannong 23 as test material,a field experiment was conducted by increasing the relative soil moisture content to 70% and 65% at jointing and anthesis stages. Four nitrogen levels,0 (N 0 ), 180 (N 1 ), 240 (N 2 ) and 300 kg·hm -2 (N 3 ), were designed to examine the effects of nitrogen application rates on the interception of photosynthetic active radiation (PAR) and dry matter distribution of wheat at different canopy layers. The results showed that the total stem number of wheat population at anthesis stage, the leaf area index at 10, 20 and 30 days after anthesis, PAR capture ratio at upper and middle layers and total PAR capture ratio in wheat canopy on day 20 after anthesis of treatment N 2 were significantly higher than those in the treatments of both N 0 and N 1 . Those indexes showed no significant increase when the application rate increased to 300 kg·hm -2 (N 3 ). The vegetative organ dry matter accumulation of all layers at maturity stage of treatment N 2 were significantly higher than N 0 and N 1 . Compared with treatment N 0 and N 1 , N 2 increased the grain and total dry matter accumulation by 36.7% and 35.4%, 9.5% and 10.2%, respectively, but had no significant difference with treatment N 3 . The vegetative organ dry matter accumulation at all layers, grain and total dry matter accumulation were significantly and positively correlated with PAR capture ratio at upper and middle layers, and had no significant correlation with that at lower layer. The vegetative organ dry matter accumulation at all layers was significantly and positively correlated with grain dry matter accumulation. The application rate at 240 kg·hm -2 (N 2 ) would be the optimum treatment under the present experimental condition.

Acoustic manipulation of active spherical carriers: Generation of negative radiation force

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rajabi, Majid, E-mail: majid_rajabi@iust.ac.ir; Mojahed, Alireza

2016-09-15

This paper examines theoretically a novel mechanism of generating negative (pulling) radiation force for acoustic manipulation of spherical carriers equipped with piezoelectric actuators in its inner surface. In this mechanism, the spherical particle is handled by common plane progressive monochromatic acoustic waves instead of zero-/higher- order Bessel beams or standing waves field. The handling strategy is based on applying a spatially uniform harmonic electrical voltage at the piezoelectric actuator with the same frequency of handling acoustic waves, in order to change the radiation force effect from repulsive (away from source) to attractive (toward source). This study may be considered asmore » a start point for development of contact-free precise handling and entrapment technology of active carriers which are essential in many engineering and medicine applications.« less

Olive Crown Porosity Measurement Based on Radiation Transmittance: An Assessment of Pruning Effect.

PubMed

Castillo-Ruiz, Francisco J; Castro-Garcia, Sergio; Blanco-Roldan, Gregorio L; Sola-Guirado, Rafael R; Gil-Ribes, Jesus A

2016-05-19

Crown porosity influences radiation interception, air movement through the fruit orchard, spray penetration, and harvesting operation in fruit crops. The aim of the present study was to develop an accurate and reliable methodology based on transmitted radiation measurements to assess the porosity of traditional olive trees under different pruning treatments. Transmitted radiation was employed as an indirect method to measure crown porosity in two olive orchards of the Picual and Hojiblanca cultivars. Additionally, three different pruning treatments were considered to determine if the pruning system influences crown porosity. This study evaluated the accuracy and repeatability of four algorithms in measuring crown porosity under different solar zenith angles. From a 14° to 30° solar zenith angle, the selected algorithm produced an absolute error of less than 5% and a repeatability higher than 0.9. The described method and selected algorithm proved satisfactory in field results, making it possible to measure crown porosity at different solar zenith angles. However, pruning fresh weight did not show any relationship with crown porosity due to the great differences between removed branches. A robust and accurate algorithm was selected for crown porosity measurements in traditional olive trees, making it possible to discern between different pruning treatments.

Effect of ionizing radiation on the physiological activities of ethanol extract from hizikia fusiformis cooking drips.

PubMed

Kim, Hyun-Joo; Choi, Jong-il; Kim, Duk-Jin; Kim, Jae-Hun; Soo Chun, Byeong; Hyun Ahn, Dong; Sun Yook, Hong; Byun, Myung-Woo; Kim, Mi-Jung; Shin, Myung-Gon; Lee, Ju-Woon

2009-01-01

Although the byproduct from Hizikia fusiformis industry had many nutrients, it is being wasted. In this study, the physiological activities of cooking drip extracts from H. fusiformis (CDHF) were determined to investigate the effect of a gamma and an electron beam irradiations. DPPH radical scavenging activity and tyrosinase and ACE inhibition effects of the gamma and electron beam irradiated CDHF extracts were increased with increasing irradiation dose. These were reasoned by the increase in the content of the total polyphenolic compound of CDHF by the gamma and electron beam irradiation. There were no differences for the radiation types. These results show that ionizing radiation could be used for enhancing the functional activity of CDHF which is a major by-product in Hizikia fusiformis processing, in various applications.

Effects of ionizing radiation on the enzyme activities and ultrastructural changes of poultry

NASA Astrophysics Data System (ADS)

Hwang, H.-I.; Hau, L.-B.

1995-02-01

Enzyme-catalyzed changes are generally recognized as one of the major reasons for fresh meat deterioration after irradiation. In this study, the effects of ionizing radiation and storage on the enzyme activities of poultry as well as the ultrastructural change of muscle were evaluated. When chicken breasts were irradiated at 4°C and -20°C, both Ca 2+-dependent protease and cathepsin D showed some degree of resistance to irradiation. The activities of those two enzymes decreased with the increase of irradiation doses. During storage, Ca 2+-dependent proteases showed a marked decrease in activity. On the other hand, the cathepsin D activity was not significantly changed at either 4°C or -20°C after 20 days. Transmission electron microscope examination showed no structural changes of the myofibrils with a radiation dose of up to 10 kGy at either 4°C or -20°C. Freezing protected the irradiated chicken breasts from autolytic enzymes damage during storage. In contrast, considerable sarcomere degradation occurred in Z-line for irradiated samples when stored at 4°C for 20 days. The action of the proteolytic enzymes may have been responsible for the sarcomere degradation in irradiated chicken breasts.

Scattering and Absorption of E&M radiation by small particles-applications to study impact of biomass aerosols on climate

NASA Astrophysics Data System (ADS)

Bililign, Solomon; Singh, Sujeeta; Fiddler, Marc; Smith, Damon

2015-03-01

The phenomena of scattering, absorption, and emission of light and other electromagnetic radiation by small particles are central to many science and engineering disciplines. Absorption of solar radiation by black carbon aerosols has a significant impact on the atmospheric energy distribution and hydrologic processes. By intercepting incoming solar radiation before it reaches the surface, aerosols heat the atmosphere and, in turn, cool the surface. The magnitude of the atmospheric forcing induced by anthropogenic absorbing aerosols, mainly black carbon (BC) emitted from biomass burning and combustion processes has been suggested to be comparable to the atmospheric forcing by all greenhouse gases (GHGs). Despite the global abundance of biomass burning for cooking, forests clearing for agriculture and wild fires, the optical properties of these aerosols have not been characterized at wide range of wavelengths. Our laboratory uses a combination of Cavity ring down spectroscopy and integrating nephelometry to measure optical properties of (extinction, absorption and scattering coefficients) of biomass aerosols. Preliminary results will be presented. Supported by the Department of Defense under Grant #W911NF-11-1-0188.

The influence of super-high-frequency radiation on the enzyme activity and number of microorganisms in soils of southern Russia

NASA Astrophysics Data System (ADS)

Denisova, T. V.; Kolesnikov, S. I.

2009-04-01

The effects of super-high-frequency radiation (SHF radiation) on the microflora and enzymatic activity of an ordinary chernozem, a chestnut soil, a brown forest soil, and gray sands were studied. The exposure time of the 800-W SHF radiation was 30 s, 1, 10, and 60 min. The activity of the soil enzymes (catalase and invertase) was found to be more resistant to the action of SHF radiation than the number of microorganisms (ammonifying bacteria (including sporogenous ones), bacteria of the genus Azotobacter, and micromycetes). According to the resistance of the enzymes, the soils studied form the following sequence: gray sands > ordinary chernozem ≥ chestnut soil > brown forest soil. Under the action of the SHF radiation, the number of microorganisms in the ordinary chernozem decreased to a lesser extent.

Introduction to Radiation Issues for International Space Station Extravehicular Activities. Chapter 1

NASA Technical Reports Server (NTRS)

Shavers, M. R.; Saganti, P. B.; Miller, J.; Cucinotta, F. A.

2003-01-01

The International Space Station (ISS) provides significant challenges for radiation protection of the crew due to a combination of circumstances including: the extended duration of missions for many crewmembers, the exceptionally dynamic nature of the radiation environment in ISS orbit, and the necessity for numerous planned extravehicular activities (EVA) for station construction and maintenance. Radiation protection requires accurate radiation dose measurements and precise risk modeling of the transmission of high fluxes of energetic electrons and protons through the relatively thin shielding provided by the space suits worn during EVA. Experiments and analyses have been performed due to the necessity to assure complete radiation safety for the EVA crew and thereby ensure mission success. The detailed characterization described of the material and topological properties of the ISS space suits can be used as a basis for design of space suits used in future exploration missions. In radiation protection practices, risk from exposure to ionizing radiation is determined analytically by the level of exposure, the detrimental quality of the radiation field, the inherent radiosensitivity of the tissues or organs irradiated, and the age and gender of the person at the time of exposure. During low Earth orbit (LEO) EVA, the relatively high fluxes of low-energy electrons and protons lead to large variations in exposure of the skin, lens of the eye, and tissues in other shallow anatomical locations. The technical papers in this publication describe a number of ground-based experiments that precisely measure the thickness of the NASA extravehicular mobility unit (EMU) and Russian Zvezda Orlan-M suits using medical computerized tomography (CT) X-ray analysis, and particle accelerator experiments that measure the minimum kinetic energy required by electrons and photons to penetrate major components of the suits. These studies provide information necessary for improving the

Fast adaptation of the internal model of gravity for manual interceptions: evidence for event-dependent learning.

PubMed

Zago, Myrka; Bosco, Gianfranco; Maffei, Vincenzo; Iosa, Marco; Ivanenko, Yuri P; Lacquaniti, Francesco

2005-02-01

We studied how subjects learn to deal with two conflicting sensory environments as a function of the probability of each environment and the temporal distance between repeated events. Subjects were asked to intercept a visual target moving downward on a screen with randomized laws of motion. We compared five protocols that differed in the probability of constant speed (0g) targets and accelerated (1g) targets. Probability ranged from 9 to 100%, and the time interval between consecutive repetitions of the same target ranged from about 1 to 20 min. We found that subjects systematically timed their responses consistent with the assumption of gravity effects, for both 1 and 0g trials. With training, subjects rapidly adapted to 0g targets by shifting the time of motor activation. Surprisingly, the adaptation rate was independent of both the probability of 0g targets and their temporal distance. Very few 0g trials sporadically interspersed as catch trials during immersive practice with 1g trials were sufficient for learning and consolidation in long-term memory, as verified by retesting after 24 h. We argue that the memory store for adapted states of the internal gravity model is triggered by individual events and can be sustained for prolonged periods of time separating sporadic repetitions. This form of event-related learning could depend on multiple-stage memory, with exponential rise and decay in the initial stages followed by a sample-and-hold module.

Simulation of TGF-Beta Activation by Low-Dose HZE Radiation in a Cell Culture

NASA Technical Reports Server (NTRS)

Plante, Ianik; Cucinotta, Francis A.

2009-01-01

High charge (Z) and energy (E) (HZE) nuclei comprised in the galactic cosmic rays are main contributors to space radiation risk. They induce many lesions in living matter such as non-specific oxidative damage and the double-strand breaks (DSBs), which are considered key precursors of early and late effects of radiation. There is increasing evidence that cells respond collectively rather than individually to radiation, suggesting the importance of cell signaling1. The transforming growth factor (TGF ) is a signaling peptide that is expressed in nearly all cell type and regulates a large array of cellular processes2. TGF have been shown to mediate cellular response to DNA damage3 and to induce apoptosis in non-irradiated cells cocultured with irradiated cells4. TFG molecules are secreted by cells in an inactive complex known as the latency-associated peptide (LAP). TGF is released from the LAP by a conformational change triggered by proteases, thrombospondin-1, integrins, acidic conditions and .OH radical5. TGF then binds to cells receptors and activates a cascade of events mediated by Smad proteins6, which might interfere with the repair of DNA. Meanwhile, increasingly sophisticated Brownian Dynamics (BD) algorithms have appeared recently in the literature7 and can be applied to study the interaction of molecules with receptors. These BD computer models have contributed to the elucidation of signal transduction, ligand accumulation and autocrine loops in the epidermal growth factor (EGF) and its receptor (EFGR) system8. To investigate the possible roles of TGF in an irradiated cell culture, our Monte-Carlo simulation codes of the radiation track structure9 will be used to calculate the activation of TFG triggered by .OH produced by low doses of HZE ions. The TGF molecules will then be followed by a BD algorithm in a medium representative of a cell culture to estimate the number of activated receptors.

Cell Cycle Regulators Guide Mitochondrial Activity in Radiation-Induced Adaptive Response

PubMed Central

Alexandrou, Aris T.

2014-01-01

Abstract Significance: There are accruing concerns on potential genotoxic agents present in the environment including low-dose ionizing radiation (LDIR) that naturally exists on earth's surface and atmosphere and is frequently used in medical diagnosis and nuclear industry. Although its long-term health risk is being evaluated and remains controversial, LDIR is shown to induce temporary but significant adaptive responses in mammalian cells and animals. The mechanisms guiding the mitochondrial function in LDIR-induced adaptive response represent a unique communication between DNA damage and cellular metabolism. Elucidation of the LDIR-regulated mitochondrial activity may reveal new mechanisms adjusting cellular function to cope with hazardous environmental stress. Recent Advances: Key cell cycle regulators, including Cyclin D1/CDK4 and Cyclin B1/cyclin-dependent kinase 1 (CDK1) complexes, are actively involved in the regulation of mitochondrial functions via phosphorylation of their mitochondrial targets. Accumulating new evidence supports a concept that the Cyclin B1/CDK1 complex acts as a mediator in the cross talk between radiation-induced DNA damage and mitochondrial functions to coordinate cellular responses to low-level genotoxic stresses. Critical Issues: The LDIR-mediated mitochondrial activity via Cyclin B1/CDK1 regulation is an irreplaceable network that is able to harmonize vital cellular functions with adjusted mitochondrial metabolism to enhance cellular homeostasis. Future Directions: Further investigation of the coordinative mechanism that regulates mitochondrial activities in sublethal stress conditions, including LDIR, will reveal new insights of how cells cope with genotoxic injury and will be vital for future targeted therapeutic interventions that reduce environmental injury and cancer risk. Antioxid. Redox Signal. 20, 1463–1480. PMID:24180340

Use of descriptors of ecosystem functioning for monitoring a national park network: a remote sensing approach.

PubMed

Alcaraz-Segura, Domingo; Cabello, Javier; Paruelo, José M; Delibes, Miguel

2009-01-01

Baseline assessments and monitoring of protected areas are essential for making management decisions, evaluating the effectiveness of management practices, and tracking the effects of global changes. For these purposes, the analysis of functional attributes of ecosystems (i.e., different aspects of the exchange of matter and energy) has advantages over the traditional use of structural attributes, like a quicker response to disturbances and the fact that they are easily monitored through remote sensing. In this study, we described the spatiotemporal patterns of different aspects of the ecosystem functioning of the Spanish national parks and their response to environmental changes between 1982 and 2006. To do so, we used the NOAA/AVHRR-GIMMS dataset of the Normalized Difference Vegetation Index (NDVI), a linear estimator of the fraction of photosynthetic active radiation intercepted by vegetation, which is the main control of carbon gains. Nearly all parks have significantly changed during the last 25 years: The radiation interception has increased, the contrast between the growing and nongrowing seasons has diminished, and the dates of maximum and minimum interception have advanced. Some parks concentrated more changes than others and the degree of change varied depending on their different environmental conditions, management, and conservation histories. Our approach identified reference conditions and temporal changes for different aspects of ecosystem functioning, which can be used for management purposes of protected areas in response to global changes.

The impact of radiatively active water-ice clouds on Martian mesoscale atmospheric circulations

NASA Astrophysics Data System (ADS)

Spiga, A.; Madeleine, J.-B.; Hinson, D.; Navarro, T.; Forget, F.

2014-04-01

Background and Goals Water ice clouds are a key component of the Martian climate [1]. Understanding the properties of the Martian water ice clouds is crucial to constrain the Red Planet's climate and hydrological cycle both in the present and in the past [2]. In recent years, this statement have become all the more true as it was shown that the radiative effects of water ice clouds is far from being as negligible as hitherto believed; water ice clouds plays instead a key role in the large-scale thermal structure and dynamics of the Martian atmosphere [3, 4, 5]. Nevertheless, the radiative effect of water ice clouds at lower scales than the large synoptic scale (the so-called meso-scales) is still left to be explored. Here we use for the first time mesoscale modeling with radiatively active water ice clouds to address this open question.

Modeling the ratio of photosynthetically active radiation to broadband global solar radiation using ground and satellite-based data in the tropics

NASA Astrophysics Data System (ADS)

Janjai, S.; Wattan, R.; Sripradit, A.

2015-12-01

Data from four stations in Thailand are used to model the ratio of photosynthetically active radiation (PAR) to broadband global solar radiation. The model expresses the ratio of PAR-to-broadband global solar radiation as a function of cloud index, aerosol optical depth, precipitable water, total ozone column and solar zenith angle. Data from the MTSAT-1R and OMI/AURA satellites are used to estimate the cloud index and total ozone column, respectively at each of the four stations, while aerosol optical depth and precipitable water are retrieved from Aerosol Robotic Network (AERONET) sunphotometer measurements, also available at each station. When tested against hourly measurements, the model exhibits a coefficient of variance (R2) equal to or better than 0.96, and root mean square difference (RMSD) in the range of 7.3-7.9% and mean bias difference (MBD) of -4.5% to 3.5%. The model compares favorably with other existing models.

Energy management of three-dimensional minimum-time intercept. [for aircraft flight optimization

NASA Technical Reports Server (NTRS)

Kelley, H. J.; Cliff, E. M.; Visser, H. G.

1985-01-01

A real-time computer algorithm to control and optimize aircraft flight profiles is described and applied to a three-dimensional minimum-time intercept mission. The proposed scheme has roots in two well known techniques: singular perturbations and neighboring-optimal guidance. Use of singular-perturbation ideas is made in terms of the assumed trajectory-family structure. A heading/energy family of prestored point-mass-model state-Euler solutions is used as the baseline in this scheme. The next step is to generate a near-optimal guidance law that will transfer the aircraft to the vicinity of this reference family. The control commands fed to the autopilot (bank angle and load factor) consist of the reference controls plus correction terms which are linear combinations of the altitude and path-angle deviations from reference values, weighted by a set of precalculated gains. In this respect the proposed scheme resembles neighboring-optimal guidance. However, in contrast to the neighboring-optimal guidance scheme, the reference control and state variables as well as the feedback gains are stored as functions of energy and heading in the present approach. Some numerical results comparing open-loop optimal and approximate feedback solutions are presented.

A Novel Passive Tracking Scheme Exploiting Geometric and Intercept Theorems

PubMed Central

Zhou, Biao; Sun, Chao; Ahn, Deockhyeon; Kim, Youngok

2018-01-01

Passive tracking aims to track targets without assistant devices, that is, device-free targets. Passive tracking based on Radio Frequency (RF) Tomography in wireless sensor networks has recently been addressed as an emerging field. The passive tracking scheme using geometric theorems (GTs) is one of the most popular RF Tomography schemes, because the GT-based method can effectively mitigate the demand for a high density of wireless nodes. In the GT-based tracking scheme, the tracking scenario is considered as a two-dimensional geometric topology and then geometric theorems are applied to estimate crossing points (CPs) of the device-free target on line-of-sight links (LOSLs), which reveal the target’s trajectory information in a discrete form. In this paper, we review existing GT-based tracking schemes, and then propose a novel passive tracking scheme by exploiting the Intercept Theorem (IT). To create an IT-based CP estimation scheme available in the noisy non-parallel LOSL situation, we develop the equal-ratio traverse (ERT) method. Finally, we analyze properties of three GT-based tracking algorithms and the performance of these schemes is evaluated experimentally under various trajectories, node densities, and noisy topologies. Analysis of experimental results shows that tracking schemes exploiting geometric theorems can achieve remarkable positioning accuracy even under rather a low density of wireless nodes. Moreover, the proposed IT scheme can provide generally finer tracking accuracy under even lower node density and noisier topologies, in comparison to other schemes. PMID:29562621

Visual and somatic sensory feedback of brain activity for intuitive surgical robot manipulation.

PubMed

Miura, Satoshi; Matsumoto, Yuya; Kobayashi, Yo; Kawamura, Kazuya; Nakashima, Yasutaka; Fujie, Masakatsu G

2015-01-01

This paper presents a method to evaluate the hand-eye coordination of the master-slave surgical robot by measuring the activation of the intraparietal sulcus in users brain activity during controlling virtual manipulation. The objective is to examine the changes in activity of the intraparietal sulcus when the user's visual or somatic feedback is passed through or intercepted. The hypothesis is that the intraparietal sulcus activates significantly when both the visual and somatic sense pass feedback, but deactivates when either visual or somatic is intercepted. The brain activity of three subjects was measured by the functional near-infrared spectroscopic-topography brain imaging while they used a hand controller to move a virtual arm of a surgical simulator. The experiment was performed several times with three conditions: (i) the user controlled the virtual arm naturally under both visual and somatic feedback passed, (ii) the user moved with closed eyes under only somatic feedback passed, (iii) the user only gazed at the screen under only visual feedback passed. Brain activity showed significantly better control of the virtual arm naturally (p<;0.05) when compared with moving with closed eyes or only gazing among all participants. In conclusion, the brain can activate according to visual and somatic sensory feedback agreement.

A comparison of time-optimal interception trajectories for the F-8 and F-15

NASA Technical Reports Server (NTRS)

Calise, Anthony J.; Pettengill, James B.

1990-01-01

The simulation results of a real time control algorithm for onboard computation of time-optimal intercept trajectories for the F-8 and F-15 aircraft are given. Due to the inherent aerodynamic and propulsion differences in the aircraft, there are major differences in their optimal trajectories. The significant difference in the two aircrafts are their flight envelopes. The F-8's optimal cruise velocity is thrust limited, while the F-15's optimal cruise velocity is at the intersection of the Mach and dynamic pressure constraint boundaries. This inherent difference necessitated the development of a proportional thrust controller for use as the F-15 approaches it's optimal cruise energy. Documented here is the application of singular perturbation theory to the trajectory optimization problem, along with a summary of the control algorithms. Numerical results for the two aircraft are compared to illustrate the performance of the minimum time algorithm, and to compute the resulting flight paths.

Estimation of land photosynthetically active radiation in clear sky using MODIS atmosphere and land products

NASA Astrophysics Data System (ADS)

Xie, Xiaoping; Gao, Wei; Gao, Zhiqiang

2008-08-01

Photosynthetically active radiation (PAR) is an essential parameter in vegetation growth model and soil carbon sequestration models. A method is presented with which instantaneous PAR can be calculated with high accuracy from Moderate Resolution Imaging Spectroradiometer (MODIS) atmosphere and land products. The method is based on a simplification of the general radiative transfer equation, which considers five major processes of attenuation of solar radiation: Rayleigh scattering, absorption by ozone and water vapor, aerosol scattering, multiply reflectance between surface and atmosphere. Comparing 108 retrieveled results to filed measured PAR in Yucheng station of Chinese Ecosystem Research Network (CERN) in 2006, and the r-square of 0.855 indicates that the computed results can interpret actual PAR well.

Modeling Rainfall-Runoff Dynamics in Tropical, Urban Socio-Hydrological Systems: Green Infrastructure and Variable Precipitation Interception

NASA Astrophysics Data System (ADS)

Nytch, C. J.; Meléndez-Ackerman, E. J.

2014-12-01

There is a pressing need to generate spatially-explicit models of rainfall-runoff dynamics in the urban humid tropics that can characterize flow pathways and flood magnitudes in response to erratic precipitation events. To effectively simulate stormwater runoff processes at multiple scales, complex spatio-temporal parameters such as rainfall, evapotranspiration, and antecedent soil moisture conditions must be accurately represented, in addition to uniquely urban factors including stormwater conveyance structures and connectivity between green and gray infrastructure elements. In heavily urbanized San Juan, Puerto Rico, stream flashiness and frequent flooding are major issues, yet still lacking is a hydrological analysis that models the generation and movement of fluvial and pluvial stormwater through the watershed. Our research employs a novel and multifaceted approach to dealing with this problem that integrates 1) field-based rainfall interception and infiltration methodologies to quantify the hydrologic functions of natural and built infrastructure in San Juan; 2) remote sensing analysis to produce a fine-scale typology of green and gray cover types in the city and determine patterns of spatial distribution and connectivity; 3) assessment of precipitation and streamflow variability at local and basin-wide scales using satellite and radar precipitation estimates in concert with rainfall and stream gauge point data and participatory flood mapping; 4) simulation of historical, present-day, and future stormwater runoff scenarios with a fully distributed hydrologic model that couples diverse components of urban socio-hydrological systems from formal and informal knowledge sources; and 5) bias and uncertainty analysis of parameters and model structure within a Bayesian hierarchical framework. Preliminary results from the rainfall interception study suggest that canopy structure and leaf area index of different tree species contribute to variable throughfall and

Improved estimations of gross primary production using satellite-derived photosynthetically active radiation

NASA Astrophysics Data System (ADS)

Cai, Wenwen; Yuan, Wenping; Liang, Shunlin; Zhang, Xiaotong; Dong, Wenjie; Xia, Jiangzhou; Fu, Yang; Chen, Yang; Liu, Dan; Zhang, Qiang

2014-01-01

Terrestrial vegetation gross primary production (GPP) is an important variable in determining the global carbon cycle as well as the interannual variability of the atmospheric CO2 concentration. The accuracy of GPP simulation is substantially affected by several critical model drivers, one of the most important of which is photosynthetically active radiation (PAR) which directly determines the photosynthesis processes of plants. In this study, we examined the impacts of uncertainties in radiation products on GPP estimates in China. Two satellite-based radiation products (GLASS and ISCCP), three reanalysis products (MERRA, ECMWF, and NCEP), and a blended product of reanalysis and observations (Princeton) were evaluated based on observations at hundreds of sites. The results revealed the highest accuracy for two satellite-based products over various temporal and spatial scales. The three reanalysis products and the Princeton product tended to overestimate radiation. The GPP simulation driven by the GLASS product exhibited the highest consistency with those derived from site observations. Model validation at 11 eddy covariance sites suggested the highest model performance when utilizing the GLASS product. Annual GPP in China driven by GLASS was 5.55 Pg C yr-1, which was 68.85%-94.87% of those derived from the other products. The results implied that the high spatial resolution, satellite-derived GLASS PAR significantly decreased the uncertainty of the GPP estimates at the regional scale.

[Effect of Low-Intensity 900 MHz Frequency Electromagnetic Radiation on Rat Brain Enzyme Activities Linked to Energy Metabolism].

PubMed

Petrosyan, M S; Nersesova, L S; Gazaryants, M G; Meliksetyan, G O; Malakyan, M G; Bajinyan, S A; Akopian, J I

2015-01-01

The research deals with the effect of low-intensity 900 MHz frequency electromagnetic radiation (EMR), power density 25 μW/cm2, on the following rat brain and blood serum enzyme activities: creatine kinase (CK), playing a central role in the process of storing and distributing the cell energy, as well as alanine aminotransferase (ALT) and aspartate aminotransferase (AST) that play a key role in providing the conjunction of carbohydrate and amino acid metabolism. The comparative analysis of the changes in the enzyme activity studied at different times following the two-hour single, as well as fractional, radiation equivalent of the total time showed that the most radiosensitive enzyme is the brain creatine kinase, which may then be recommended as a marker of the radio frequency radiation impact. According to the analysis of the changing dynamics of the CK, ALT and AST activity level, with time these changes acquire the adaptive character and are directed to compensate the damaged cell energy metabolism.

Pregnancy interceptive efficacy and biological profile of 3-amino-6,7-dimethoxy-1H-pyrazolo [3,4-b] quinoline (compound 85/83) in rodents.

PubMed

Mehrotra, P K; Shukla, R; Dwivedi, A; Srivastava, R P; Bhat, N; Seth, M; Bhaduri, A P; Kamboj, V P

1991-05-01

Administration of compound 85/83 during the peri- and post-implantation period intercepted pregnancy in hamster and guinea pig by parenteral route and in hamster by oral route also. The m.e.d. for hamster and guinea pig was 10 and 20 mg/kg, respectively; lower doses were less effective. Restricting the administration to early post-implantation schedule interrupted pregnancy partially in both species. The compound was, however, ineffective in rat and in the pre-implantation schedule (days 1-4 post-coitum) in hamster. When tested in vitro on growing trophoblasts at 13.8 x 10(-5) M concentration, it prevented growth and caused degeneration of the cells within 24 h; lower concentration (9.2 x 10(-5) M) was less effective. The compound was found to be devoid of estrogenic, antiestrogenic, progestational and antiprogestational properties in conventional bioassays. In hormone competition assays, its relative binding affinity (RBA) to estrogen receptor was negligible (0.002% of estradiol-17 beta), while for uterine cytosol progesterone receptors in rabbit and hamster was 0.06 and 0.08% of progesterone, respectively. The compound 85/83 appears to intercept pregnancy by interfering with development of trophoblast cells.

Inhibiting the phosphatidylinositide 3-kinase pathway blocks radiation-induced metastasis associated with Rho-GTPase and Hypoxia-inducible factor-1 activity.

PubMed

Burrows, Natalie; Telfer, Brian; Brabant, Georg; Williams, Kaye J

2013-09-01

Undifferentiated follicular and anaplastic thyroid tumours often respond poorly to radiotherapy and show increased metastatic potential. We evaluated radiation-induced effects on metastasis in thyroid carcinoma cells and tumours, mechanistically focusing on phosphatidylinositide 3-kinase (PI3K) and associated pathways. Migration was analysed in follicular (FTC133) and anaplastic (8505c) cells following radiotherapy (0-6 Gray) with concomitant pharmacological (GDC-0941) or genetic inhibition of PI3K. Hypoxia-inducible factor-1 (HIF-1)-activity was measured using luciferase reporter assays and was inhibited using a dominant-negative variant. Activation and subcellular localisation of target proteins were assessed via Western blot and immunofluorescence. In vivo studies used FTC133 xenografts with metastatic lung dissemination assessed ex vivo. Radiation induced migration in a HIF-dependent manner in FTC133 cells but decreased migration in 8505c's. Post-radiation HIF-activity correlated with migratory phenotype. PI3K-targeting inhibited migration under basal and irradiated conditions through inhibition of HIF-1α, Rho-GTPase expression/activity and localisation whilst having little effect on src/FAK. In vivo, radiation induced PI3K, HIF, Rho-GTPases and src but only PI3K, HIF and Rho-GTPases were inhibited by GDC-0941. Co-treatment with GDC-0941 and radiation significantly reduced metastatic dissemination versus radiotherapy alone. Radiation modifies metastatic characteristics of thyroid carcinoma cells, which can be successfully inhibited by targeting PI3K using GDC-0941 in vitro and in vivo. Copyright © 2013 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

CHARACTERIZATION OF AN ACTIVELY COOLED METAL FOIL THERMAL RADIATION SHIELD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feller, J. R.; Salerno, L. J.; Kashani, A.

2010-04-09

Zero boil-off (ZBO) or reduced boil-off (RBO) systems that involve active cooling of large cryogenic propellant tanks will most likely be required for future space exploration missions. For liquid oxygen or methane, such systems could be implemented using existing high technology readiness level (TRL) cryocoolers. However, for liquid hydrogen temperatures (approx20 K) no such coolers exist. In order to partially circumvent this technology gap, the concept of broad area cooling (BAC) has been developed, whereby a low mass thermal radiation shield could be maintained at temperatures around 100 K by steady circulation of cold pressurized gas through a network ofmore » narrow tubes. By this method it is possible to dramatically reduce the radiative heat leak to the 20 K tank. A series of experiments, designed to investigate the heat transfer capabilities of BAC systems, have been conducted at NASA Ames Research Center (ARC). Results of the final experiment in this series, investigating heat transfer from a metal foil film to a distributed cooling line, are presented here.« less

Mapping diffuse photosynthetically active radiation from satellite data in Thailand

NASA Astrophysics Data System (ADS)

Choosri, P.; Janjai, S.; Nunez, M.; Buntoung, S.; Charuchittipan, D.

2017-12-01

In this paper, calculation of monthly average hourly diffuse photosynthetically active radiation (PAR) using satellite data is proposed. Diffuse PAR was analyzed at four stations in Thailand. A radiative transfer model was used for calculating the diffuse PAR for cloudless sky conditions. Differences between the diffuse PAR under all sky conditions obtained from the ground-based measurements and those from the model are representative of cloud effects. Two models are developed, one describing diffuse PAR only as a function of solar zenith angle, and the second one as a multiple linear regression with solar zenith angle and satellite reflectivity acting linearly and aerosol optical depth acting in logarithmic functions. When tested with an independent data set, the multiple regression model performed best with a higher coefficient of variance R2 (0.78 vs. 0.70), lower root mean square difference (RMSD) (12.92% vs. 13.05%) and the same mean bias difference (MBD) of -2.20%. Results from the multiple regression model are used to map diffuse PAR throughout the country as monthly averages of hourly data.

Spectral estimators of absorbed photosynthetically active radiation in corn canopies

NASA Technical Reports Server (NTRS)

Gallo, K. P.; Daughtry, C. S. T.; Bauer, M. E.

1985-01-01

Most models of crop growth and yield require an estimate of canopy leaf area index (LAI) or absorption of radiation. Relationships between photosynthetically active radiation (PAR) absorbed by corn canopies and the spectral reflectance of the canopies were investigated. Reflectance factor data were acquired with a Landsat MSS band radiometer. From planting to silking, the three spectrally predicted vegetation indices examined were associated with more than 95 percent of the variability in absorbed PAR. The relationships developed between absorbed PAR and the three indices were evaluated with reflectance factor data acquired from corn canopies planted in 1979 through 1982. Seasonal cumulations of measured LAI and each of the three indices were associated with greater than 50 percent of the variation in final grain yields from the test years. Seasonal cumulations of daily absorbed PAR were associated with up to 73 percent of the variation in final grain yields. Absorbed PAR, cumulated through the growing season, is a better indicator of yield than cumulated leaf area index. Absorbed PAR may be estimated reliably from spectral reflectance data of crop canopies.

Spectral estimators of absorbed photosynthetically active radiation in corn canopies

NASA Technical Reports Server (NTRS)

Gallo, K. P.; Daughtry, C. S. T.; Bauer, M. E.

1984-01-01

Most models of crop growth and yield require an estimate of canopy leaf area index (LAI) or absorption of radiation. Relationships between photosynthetically active radiation (PAR) absorbed by corn canopies and the spectral reflectance of the canopies were investigated. Reflectance factor data were acquired with a LANDSAT MSS band radiometer. From planting to silking, the three spectrally predicted vegetation indices examined were associated with more than 95% of the variability in absorbed PAR. The relationships developed between absorbed PAR and the three indices were evaluated with reflectance factor data acquired from corn canopies planted in 1979 through 1982. Seasonal cumulations of measured LAI and each of the three indices were associated with greater than 50% of the variation in final grain yields from the test years. Seasonal cumulations of daily absorbed PAR were associated with up to 73% of the variation in final grain yields. Absorbed PAR, cumulated through the growing season, is a better indicator of yield than cumulated leaf area index. Absorbed PAR may be estimated reliably from spectral reflectance data of crop canopies.

Exploiting different active silicon detectors in the International Space Station: ALTEA and DOSTEL galactic cosmic radiation (GCR) measurements

NASA Astrophysics Data System (ADS)

Narici, Livo; Berger, Thomas; Burmeister, Sönke; Di Fino, Luca; Rizzo, Alessandro; Matthiä, Daniel; Reitz, Günther

2017-08-01

The solar system exploration by humans requires to successfully deal with the radiation exposition issue. The scientific aspect of this issue is twofold: knowing the radiation environment the astronauts are going to face and linking radiation exposure to health risks. Here we focus on the first issue. It is generally agreed that the final tool to describe the radiation environment in a space habitat will be a model featuring the needed amount of details to perform a meaningful risk assessment. The model should also take into account the shield changes due to the movement of materials inside the habitat, which in turn produce changes in the radiation environment. This model will have to undergo a final validation with a radiation field of similar complexity. The International Space Station (ISS) is a space habitat that features a radiation environment inside which is similar to what will be found in habitats in deep space, if we use measurements acquired only during high latitude passages (where the effects of the Earth magnetic field are reduced). Active detectors, providing time information, that can easily select data from different orbital sections, are the ones best fulfilling the requirements for these kinds of measurements. The exploitation of the radiation measurements performed in the ISS by all the available instruments is therefore mandatory to provide the largest possible database to the scientific community, to be merged with detailed Computer Aided Design (CAD) models, in the quest for a full model validation. While some efforts in comparing results from multiple active detectors have been attempted, a thorough study of a procedure to merge data in a single data matrix in order to provide the best validation set for radiation environment models has never been attempted. The aim of this paper is to provide such a procedure, to apply it to two of the most performing active detector systems in the ISS: the Anomalous Long Term Effects in Astronauts (ALTEA

THE EFFECT OF RADIATION AND POLYMYXIN B SULFATE ON THE SERIUM BETA- GLUCURONIDASE ACTIVITY LEVEL IN CANCER PATIENTS: A PRELIMINARY REPORT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bartalos, M.; Gyoerkey, F.

1962-01-01

Serial serum BETA -glucuronidase activity determinations showed a consistently higher level in 50 cancer patients as compared with a group of healthy adults. In 1 group of these patients treated with radiation alone, the serum BETA glucuronidase level rose in all reaching the highest peak about the 12th day. Another group of these cancer patients was treated with radiation and polymyxin B each day for 2 consecutive days. In all, the serum activity showed a sharp fall after the 2nd injection which was followed by clinical improvement. In order to exclude the possibility of a direct deactivating effect of radiationmore » of BETA -glucuronidase in the circulating blood, the following in vitro experiments were performed. A pure crystalline enzyme was dissolved in distilled water to an approximately similar concentration to that found in cancer patients' serums with and without polymyxin and exposed to 50,000 r radiation. This did not lower the enzyme activity level. Pleural fluid from cancer patients showing high BETA -glucoronidase activity, with and without polymyxin, exposed to a similar dose of radiation showed no change in activity. (H.H.D.)« less

Attenuation mechanisms of N-nitrosodimethylamine at an operating intercept and treat groundwater remediation system.

PubMed

Gunnison, D; Zappi, M E; Teeter, C; Pennington, J C; Bajpai, R

2000-04-03

The North Boundary Containment System (NBCS), an intercept-and-treat system, was established at Rocky Mountain Arsenal (RMA), Commerce City, CO, to remove low-level organic contaminants from a groundwater plume exiting RMA to the north and northwest. N-nitrosodimethylamine (NDMA) was detected in groundwater collected from the dewatering and recharge zones of the NBCS system. Concern over the fate of NDMA, in terms of potentially exiting the boundaries of the arsenal, prompted an investigation to evaluate potential attenuation mechanisms for NDMA within the alluvial aquifer system and within the NBCS itself. Groundwater, soil, and granular activated carbon (GAC) samples were taken from key locations in the NBCS system. Soil and GAC samples were assayed for sorption kinetics and for adsorption and desorption properties using 14C-labeled NDMA. NDMA biodegradation experiments were conducted by following 14CO(2) evolution from 14C-labeled NDMA in soils and GAC samples under aerobic and anaerobic conditions. The sorptive capacity of the site soils for NDMA was insignificant. Furthermore, the adsorption of the NDMA by the soil was almost completely reversible. Evaluation of the degradation potential of the native microbial consortia indicated a high level of NDMA mineralization when measured using bench-scale microcosms. The native consortia had capability to mineralize the NDMA under both aerobic and anaerobic incubations, indicating facultative characteristics. Testing of the local groundwater chemistry revealed that the area of the aquifer of interest was microaerobic and neutral in pH. These conditions were optimal for NDMA removal. While sorption was insignificant, degradation was a significant attenuation mechanism, which may be the reason that no NDMA has migrated off-site. This gives rise to the potential of a long-term sink for attenuating NDMA within the recharge zone of the treatment system.

Geometrically Thick Obscuration by Radiation-driven Outflow from Magnetized Tori of Active Galactic Nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chan, Chi-Ho; Krolik, Julian H.

2017-07-01

Near-Eddington radiation from active galactic nuclei (AGNs) has significant dynamical influence on the surrounding dusty gas, plausibly furnishing AGNs with geometrically thick obscuration. We investigate this paradigm with radiative magnetohydrodynamics simulations. The simulations solve the magnetohydrodynamics equations simultaneously with the infrared (IR) and ultraviolet (UV) radiative transfer (RT) equations; no approximate closure is used for RT. We find that our torus, when given a suitable sub-Keplerian angular momentum profile, spontaneously evolves toward a state in which its opening angle, density distribution, and flow pattern change only slowly. This “steady” state lasts for as long as there is gas resupply towardmore » the inner edge. The torus is best described as a midplane inflow and a high-latitude outflow. The outflow is launched from the torus inner edge by UV radiation and expands in solid angle as it ascends; IR radiation continues to drive the wide-angle outflow outside the central hole. The dusty outflow obscures the central source in soft X-rays, the IR, and the UV over three-quarters of solid angle, and each decade in column density covers roughly equal solid angle around the central source; these obscuration properties are similar to what observations imply.« less

Estimation of canopy water interception of a near-tropical montane cloud forest in Taiwan

NASA Astrophysics Data System (ADS)

Apurva, B.; Huang, C. Y.; Zhang, J.

2017-12-01

Tropical and subtropical montane cloud forests are some of the rarest and least studied ecosystems. Due to the frequent immersion of fog water with high humidity, these zones are major water sources for lowland environments and habitats for many fauna and flora. Their dependence on cloud water leaves them highly susceptible to the effects of climate change. Studies have been conducted to quantify the characteristics of the low altitude clouds such as spatial dynamics, cloud top and base heights, occurrence frequency or immersion duration. In this study, we carried out a field measurement to estimate canopy water interception (CWI), which is directly utilized by the ecosystems. The study site was a 61 ha near-tropical hinoki cypress montane cloud forest plantation in northern Taiwan at 1705 m asl. Leaves of CHOB were clipped, air-dried and attached to trees at three different canopy depths from the top to the base of canopies along a high tower. The samples were weighed before and after the occurrence of a fog event. In addition, a cylinder shaped fog gauge was installed at the ground level next to the tower to assess amount of fog water penetrating the canopy layer. After afternoon fog events with the duration of 60 minutes, we found that there was an apparent trend of decline of CWI from top (mean ± standard deviation = 0.023 g ± 0.0015 g), middle (0.021 g ± 0.0015 g) to the bottom (0.013 g ± 0.0015 g) of the canopies. Since the study site is a coniferous evergreen forest plantation with a relatively homogenous surface through seasons, with the background knowledge of the average leaf area index of 4.4, we estimated that this 61 ha site harvested 28.2 Mg of CWI for a daily fog event. We also found that no clear evidence of CWI was observed below the canopies by referring to bi-weekly records from the cylinder shaded fog gauge. Therefore, we can assume that the majority fog water was intercepted by the hinoki cypress canopy layer. This study demonstrates that a

Radiation dosimetry predicts IQ after conformal radiation therapy in pediatric patients with localized ependymoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Merchant, Thomas E.; Kiehna, Erin N.; Li Chenghong

2005-12-01

Purpose: To assess the effects of radiation dose-volume distribution on the trajectory of IQ development after conformal radiation therapy (CRT) in pediatric patients with ependymoma. Methods and Materials: The study included 88 patients (median age, 2.8 years {+-} 4.5 years) with localized ependymoma who received CRT (54-59.4 Gy) that used a 1-cm margin on the postoperative tumor bed. Patients were evaluated with tests that included IQ measures at baseline (before CRT) and at 6, 12, 24, 36, 48, and 60 months. Differential dose-volume histograms (DVH) were derived for total-brain, supratentorial-brain, and right and left temporal-lobe volumes. The data were partitionedmore » into three dose intervals and integrated to create variables that represent the fractional volume that received dose over the specified intervals (e.g., V{sub 0-20Gy}, V{sub 20-40Gy}, V{sub 40-65Gy}) and modeled with clinical variables to develop a regression equation to estimate IQ after CRT. Results: A total of 327 IQ tests were performed in 66 patients with infratentorial tumors and 20 with supratentorial tumors. The median follow-up was 29.4 months. For all patients, IQ was best estimated by age (years) at CRT; percent volume of the supratentorial brain that received doses between 0 and 20 Gy, 20 and 40 Gy, and 40 and 65 Gy; and time (months) after CRT. Age contributed significantly to the intercept (p > 0.0001), and the dose-volume coefficients were statistically significant (V{sub 0-20Gy}, p = 0.01; V{sub 20-40Gy}, p < 0.001; V{sub 40-65Gy}, p = 0.04). A similar model was developed exclusively for patients with infratentorial tumors but not supratentorial tumors. Conclusion: Radiation dosimetry can be used to predict IQ after CRT in patients with localized ependymoma. The specificity of models may be enhanced by grouping according to tumor location.« less

Saccades to future ball location reveal memory-based prediction in a virtual-reality interception task

PubMed Central

Diaz, Gabriel; Cooper, Joseph; Rothkopf, Constantin; Hayhoe, Mary

2013-01-01

Despite general agreement that prediction is a central aspect of perception, there is relatively little evidence concerning the basis on which visual predictions are made. Although both saccadic and pursuit eye-movements reveal knowledge of the future position of a moving visual target, in many of these studies targets move along simple trajectories through a fronto-parallel plane. Here, using a naturalistic and racquet-based interception task in a virtual environment, we demonstrate that subjects make accurate predictions of visual target motion, even when targets follow trajectories determined by the complex dynamics of physical interactions and the head and body are unrestrained. Furthermore, we found that, following a change in ball elasticity, subjects were able to accurately adjust their prebounce predictions of the ball's post-bounce trajectory. This suggests that prediction is guided by experience-based models of how information in the visual image will change over time. PMID:23325347

Saccades to future ball location reveal memory-based prediction in a virtual-reality interception task.

PubMed

Diaz, Gabriel; Cooper, Joseph; Rothkopf, Constantin; Hayhoe, Mary

2013-01-16

Despite general agreement that prediction is a central aspect of perception, there is relatively little evidence concerning the basis on which visual predictions are made. Although both saccadic and pursuit eye-movements reveal knowledge of the future position of a moving visual target, in many of these studies targets move along simple trajectories through a fronto-parallel plane. Here, using a naturalistic and racquet-based interception task in a virtual environment, we demonstrate that subjects make accurate predictions of visual target motion, even when targets follow trajectories determined by the complex dynamics of physical interactions and the head and body are unrestrained. Furthermore, we found that, following a change in ball elasticity, subjects were able to accurately adjust their prebounce predictions of the ball's post-bounce trajectory. This suggests that prediction is guided by experience-based models of how information in the visual image will change over time.

Radiative transfer and radiative driving of outflows in active galactic nuclei and starbursts

NASA Astrophysics Data System (ADS)

Novak, G. S.; Ostriker, J. P.; Ciotti, L.

2012-12-01

To facilitate the study of black hole fuelling, star formation and feedback in galaxies, we outline a method for treating the radial forces on interstellar gas due to absorption of photons by dust grains. The method gives the correct behaviour in all of the relevant limits [dominated by the central point source; dominated by the distributed isotropic source; optically thin; optically thick to ultraviolet (UV)/optical; optically thick to infrared (IR)] and reasonably interpolates between the limits when necessary. The method is explicitly energy conserving so that UV/optical photons that are absorbed are not lost, but are rather redistributed to the IR where they may scatter out of the galaxy. We implement the radiative transfer algorithm in a two-dimensional hydrodynamical code designed to study feedback processes in the context of early-type galaxies. We find that the dynamics and final state of simulations are measurably but only moderately affected by radiative forces on dust, even when assumptions about the dust-to-gas ratio are varied from zero to a value appropriate for the Milky Way. In simulations with high gas densities designed to mimic ultraluminous IR galaxies with a star formation rate of several hundred solar masses per year, dust makes a more substantial contribution to the dynamics and outcome of the simulation. We find that, despite the large opacity of dust to UV radiation, the momentum input to the flow from radiation very rarely exceeds L/c due to two factors: the low opacity of dust to the re-radiated IR and the tendency for dust to be destroyed by sputtering in hot gas environments. We also develop a simplification of our radiative transfer algorithm that respects the essential physics but is much easier to implement and requires a fraction of the computational cost.

Novel Concrete Chemistry Achieved with Low Dose Gamma Radiation Curing and Resistance to Neutron Activation

NASA Astrophysics Data System (ADS)

Burnham, Steven Robert

As much as 50% of ageing-related problems with concrete structures can be attributed to con-struction deficiencies at the time of placement. The most influential time affecting longevity of concrete structures is the curing phase, or commonly the initial 28 days following its placement. A novel advanced atomistic analysis of novel concrete chemistry is presented in this dissertation with the objective to improve concrete structural properties and its longevity. Based on experiments and computational models, this novel concrete chemistry is discussed in two cases: (a) concrete chemistry changes when exposed to low-dose gamma radiation in its early curing stage, thus improving its strength in a shorter period of time then curing for the conventional 28 days; (b) concrete chemistry is controlled by its atomistic components to assure strength is not reduced but that its activation due to long-term exposure to neutron flux in nuclear power plants is negligible. High dose gamma radiation is well documented as a degradation mechanism that decreases concrete's compressive strength; however, the effects of low-dose gamma radiation on the initial curing phase of concrete, having never been studied before, proved its compressive strength increases. Using a 137 Cs source, concrete samples were subjected to gamma radiation during the initial curing phase for seven, 14, and 28 days. The compressive strength after seven days is improved for gamma cured concrete by 24% and after 14 days by 76%. Concrete shows no improvement in compressive strength after 28 days of exposure to gamma radiation, showing that there is a threshold effect. Scanning Electron Microscopy is used to examine the microstructure of low-dose gamma radiation where no damage to its microstructure is found, showing no difference between gamma cured and conventionally cured concrete. Molecular dynamics modeling based on the MOPAC package is used to study how gamma radiation during the curing stage improves

European activities in radiation protection in medicine.

PubMed

Simeonov, Georgi

2015-07-01

The recently published Council Directive 2013/59/Euratom ('new European Basic Safety Standards', EU BSS) modernises and consolidates the European radiation protection legislation by taking into account the latest scientific knowledge, technological progress and experience with implementing the current legislation and by merging five existing Directives into a single piece of legislation. The new European BSS repeal previous European legislation on which the national systems for radiation protection in medicine of the 28 European Union (EU) Member States are based, including the 96/29/Euratom 'BSS' and the 97/43/Euratom 'Medical Exposure' Directives. While most of the elements of the previous legislation have been kept, there are several legal changes that will have important influence over the regulation and practice in the field all over Europe-these include, among others: (i) strengthening the implementation of the justification principle and expanding it to medically exposed asymptomatic individuals, (ii) more attention to interventional radiology, (iii) new requirements for dose recording and reporting, (iv) increased role of the medical physics expert in imaging, (v) new set of requirements for preventing and following up on accidents and (vi) new set of requirements for procedures where radiological equipment is used on people for non-medical purposes (non-medical imaging exposure). The EU Member States have to enforce the new EU BSS before January 2018 and bring into force the laws, regulations and administrative provisions necessary to comply with it. The European Commission has certain legal obligations and powers to verify the compliance of the national measures with the EU laws and, wherever necessary, issue recommendations to, or open infringement cases against, national governments. In order to ensure timely and coordinated implementation of the new European legal requirements for radiation protection, the Commission is launching several actions

The Structural Heat Intercept-Insulation-Vibration Evaluation Rig (SHIVER)

NASA Technical Reports Server (NTRS)

Johnson, W. L.; Zoeckler, J. G.; Best-Ameen, L. M.

2015-01-01

NASA is currently investigating methods to reduce the boil-off rate on large cryogenic upper stages. Two such methods to reduce the total heat load on existing upper stages are vapor cooling of the cryogenic tank support structure and integration of thick multilayer insulation systems to the upper stage of a launch vehicle. Previous efforts have flown a 2-layer MLI blanket and shown an improved thermal performance, and other efforts have ground-tested blankets up to 70 layers thick on tanks with diameters between 2 3 meters. However, thick multilayer insulation installation and testing in both thermal and structural modes has not been completed on a large scale tank. Similarly, multiple vapor cooled shields are common place on science payload helium dewars; however, minimal effort has gone into intercepting heat on large structural surfaces associated with rocket stages. A majority of the vapor cooling effort focuses on metallic cylinders called skirts, which are the most common structural components for launch vehicles. In order to provide test data for comparison with analytical models, a representative test tank is currently being designed to include skirt structural systems with integral vapor cooling. The tank is 4 m in diameter and 6.8 m tall to contain 5000 kg of liquid hydrogen. A multilayer insulation system will be designed to insulate the tank and structure while being installed in a representative manner that can be extended to tanks up to 10 meters in diameter. In order to prove that the insulation system and vapor cooling attachment methods are structurally sound, acoustic testing will also be performed on the system. The test tank with insulation and vapor cooled shield installed will be tested thermally in the B2 test facility at NASAs Plumbrook Station both before and after being vibration tested at Plumbrooks Space Power Facility.

Mapping high-resolution incident photosynthetically active radiation over land surfaces from MODIS and GOES satellite data

NASA Astrophysics Data System (ADS)

Liang, S.; Wang, K.; Wang, D.; Townshend, J.; Running, S.; Tsay, S.

2008-05-01

Incident photosynthetically active radiation (PAR) is a key variable required by almost all terrestrial ecosystem models. Many radiation efficiency models are linearly related canopy productivity to the absorbed PAR. Unfortunately, the current incident PAR products estimated from remotely sensed data or calculated by radiation models at spatial and temporal resolutions are not sufficient for carbon cycle modeling and various applications. In this study, we aim to develop incident PAR products at one kilometer scale from multiple satellite sensors, such as Moderate Resolution Imaging Spectrometer (MODIS) and Geostationary Operational Environmental Satellite (GOES) sensor. We first developed a look-up table approach to estimate instantanerous incident PAR product from MODIS (Liang et al., 2006). The temporal observations of each pixel are used to estimate land surface reflectance and look-up tables of both aerosol and cloud are searched, based on the top-of-atmosphere reflectance and surface reflectance for determining incident PAR. The incident PAR product includes both the direct and diffuse components. The calculation of a daily integrated PAR using two different methods has also been developed (Wang, et al., 2008a). The similar algorithm has been further extended to GOES data (Wang, et al., 2008b, Zheng, et al., 2008). Extensive validation activities are conducted to evaluate the algorithms and products using the ground measurements from FLUXNET and other networks. They are also compared with other satellite products. The results indicate that our approaches can produce reasonable PAR product at 1km resolution. We have generated 1km incident PAR products over North America for several years, which are freely available to the science community. Liang, S., T. Zheng, R. Liu, H. Fang, S. C. Tsay, S. Running, (2006), Estimation of incident Photosynthetically Active Radiation from MODIS Data, Journal of Geophysical Research ¡§CAtmosphere. 111, D15208,doi:10

Photosynthetically active radiation measurements in pure pine and mixed pine forests in Poland

Treesearch

Jaroslaw Smialkowski

1998-01-01

Photosynthetically active radiation (PAR) has been measured in pure pine and mixed pine forests on 15 sites in two transects in Poland: the "climatic" (from the western to the eastern border), and the "Silesian" (from the most to the less polluted part of the country). PAR was measured by using the standard procedure developed by the USDA Forest...

Interception of Cocaine by Enzyme or Antibody Delivered with Viral Gene Transfer: A Novel Strategy for Preventing Relapse in Recovering Drug Users

PubMed Central

Brimijoin, Stephen

2013-01-01

Recent progress in enzyme engineering has led to versions of human butyrylcholinesterase (BChE) that hydrolyze cocaine efficiently in plasma, reduce concentrations reaching reward neurocircuity in the brain, and weaken behavioral responses to this drug. Along with enzyme advances, increasingly avid anti-cocaine antibodies and potent anti-cocaine vaccines have also been developed. Here we review these developments and consider the potential advantages along with the risks of delivering drug-intercepting proteins via gene transfer approaches to treat cocaine addiction. PMID:22229308

Design and Testing of an Active Heat Rejection Radiator with Digital Turn-Down Capability

NASA Technical Reports Server (NTRS)

Sunada, Eric; Birur, Gajanana C.; Ganapathi, Gani B.; Miller, Jennifer; Berisford, Daniel; Stephan, Ryan

2010-01-01

NASA's proposed lunar lander, Altair, will be exposed to vastly different external environment temperatures. The challenges to the active thermal control system (ATCS) are compounded by unfavorable transients in the internal waste heat dissipation profile: the lowest heat load occurs in the coldest environment while peak loads coincide with the warmest environment. The current baseline for this fluid is a 50/50 inhibited propylene glycol/water mixture with a freeze temperature around -35 C. While the overall size of the radiator's heat rejection area is dictated by the worst case hot scenario, a turn-down feature is necessary to tolerate the worst case cold scenario. A radiator with digital turn-down capability is being designed as a robust means to maintain cabin environment and equipment temperatures while minimizing mass and power consumption. It utilizes active valving to isolate and render ineffective any number of parallel flow tubes which span across the ATCS radiator. Several options were assessed in a trade-study to accommodate flow tube isolation and how to deal with the stagnant fluid that would otherwise remain in the tube. Bread-board environmental tests were conducted for options to drain the fluid from a turned-down leg as well an option to allow a leg to freeze/thaw. Each drain option involved a positive displacement gear pump with different methods of providing a pressure head to feed it. Test results showed that a start-up heater used to generate vapor at the tube inlet held the most promise for tube evacuation. Based on these test results and conclusions drawn from the trade-study, a full-scale radiator design is being worked for the Altair mission profile.

9,400 years of cosmic radiation and solar activity from ice cores and tree rings

PubMed Central

Steinhilber, Friedhelm; Beer, Jürg; Brunner, Irene; Christl, Marcus; Fischer, Hubertus; Heikkilä, Ulla; Kubik, Peter W.; Mann, Mathias; McCracken, Ken G.; Miller, Heinrich; Miyahara, Hiroko; Oerter, Hans

2012-01-01

Understanding the temporal variation of cosmic radiation and solar activity during the Holocene is essential for studies of the solar-terrestrial relationship. Cosmic-ray produced radionuclides, such as 10Be and 14C which are stored in polar ice cores and tree rings, offer the unique opportunity to reconstruct the history of cosmic radiation and solar activity over many millennia. Although records from different archives basically agree, they also show some deviations during certain periods. So far most reconstructions were based on only one single radionuclide record, which makes detection and correction of these deviations impossible. Here we combine different 10Be ice core records from Greenland and Antarctica with the global 14C tree ring record using principal component analysis. This approach is only possible due to a new high-resolution 10Be record from Dronning Maud Land obtained within the European Project for Ice Coring in Antarctica in Antarctica. The new cosmic radiation record enables us to derive total solar irradiance, which is then used as a proxy of solar activity to identify the solar imprint in an Asian climate record. Though generally the agreement between solar forcing and Asian climate is good, there are also periods without any coherence, pointing to other forcings like volcanoes and greenhouse gases and their corresponding feedbacks. The newly derived records have the potential to improve our understanding of the solar dynamics and to quantify the solar influence on climate. PMID:22474348

9,400 years of cosmic radiation and solar activity from ice cores and tree rings.

PubMed

Steinhilber, Friedhelm; Abreu, Jose A; Beer, Jürg; Brunner, Irene; Christl, Marcus; Fischer, Hubertus; Heikkilä, Ulla; Kubik, Peter W; Mann, Mathias; McCracken, Ken G; Miller, Heinrich; Miyahara, Hiroko; Oerter, Hans; Wilhelms, Frank

2012-04-17

Understanding the temporal variation of cosmic radiation and solar activity during the Holocene is essential for studies of the solar-terrestrial relationship. Cosmic-ray produced radionuclides, such as (10)Be and (14)C which are stored in polar ice cores and tree rings, offer the unique opportunity to reconstruct the history of cosmic radiation and solar activity over many millennia. Although records from different archives basically agree, they also show some deviations during certain periods. So far most reconstructions were based on only one single radionuclide record, which makes detection and correction of these deviations impossible. Here we combine different (10)Be ice core records from Greenland and Antarctica with the global (14)C tree ring record using principal component analysis. This approach is only possible due to a new high-resolution (10)Be record from Dronning Maud Land obtained within the European Project for Ice Coring in Antarctica in Antarctica. The new cosmic radiation record enables us to derive total solar irradiance, which is then used as a proxy of solar activity to identify the solar imprint in an Asian climate record. Though generally the agreement between solar forcing and Asian climate is good, there are also periods without any coherence, pointing to other forcings like volcanoes and greenhouse gases and their corresponding feedbacks. The newly derived records have the potential to improve our understanding of the solar dynamics and to quantify the solar influence on climate.

Antiradiation Vaccine: Immunological neutralization of Radiation Toxins at Acute Radiation Syndromes.

NASA Astrophysics Data System (ADS)

Popov, Dmitri; Maliev, Slava

Introduction: Current medical management of the Acute Radiation Syndromes (ARS) does not include immune prophylaxis based on the Antiradiation Vaccine. Existing principles for the treatment of acute radiation syndromes are based on the replacement and supportive therapy. Haemotopoietic cell transplantation is recomended as an important method of treatment of a Haemopoietic form of the ARS. Though in the different hospitals and institutions, 31 pa-tients with a haemopoietic form have previously undergone transplantation with stem cells, in all cases(100%) the transplantants were rejected. Lethality rate was 87%.(N.Daniak et al. 2005). A large amount of biological substances or antigens isolated from bacterias (flagellin and derivates), plants, different types of venom (honeybees, scorpions, snakes) have been studied. This biological active substances can produce a nonspecific stimulation of immune system of mammals and protect against of mild doses of irradiation. But their radioprotection efficacy against high doses of radiation were not sufficient. Relative radioprotection characteristics or adaptive properties of antioxidants were expressed only at mild doses of radiation. However antioxidants demonstrated a very low protective efficacy at high doses of radiation. Some ex-periments demonstrated even a harmful effect of antioxidants administered to animals that had severe forms of the ARS. Only Specific Radiation Toxins roused a specific antigenic stim-ulation of antibody synthesis. An active immunization by non-toxic doses of radiation toxins includes a complex of radiation toxins that we call the Specific Radiation Determinant (SRD). Immunization must be provided not less than 24 days before irradiation and it is effective up to three years and more. Active immunization by radiation toxins significantly reduces the mortality rate (100%) and improves survival rate up to 60% compare with the 0% sur-vival rate among the irradiated animals in control groups

NASA Crew Personal Active Dosimeters (CPADs): Leveraging Novel Terrestrial Personal Radiation Monitoring Capabilities for Space Exploration

NASA Technical Reports Server (NTRS)