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Sample records for germcode gcr event-based

  1. Overview of the Graphical User Interface for the GERMcode (GCR Event-Based Risk Model)

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; Cucinotta, Francis A.

    2010-01-01

    The descriptions of biophysical events from heavy ions are of interest in radiobiology, cancer therapy, and space exploration. The biophysical description of the passage of heavy ions in tissue and shielding materials is best described by a stochastic approach that includes both ion track structure and nuclear interactions. A new computer model called the GCR Event-based Risk Model (GERM) code was developed for the description of biophysical events from heavy ion beams at the NASA Space Radiation Laboratory (NSRL). The GERMcode calculates basic physical and biophysical quantities of high-energy protons and heavy ions that have been studied at NSRL for the purpose of simulating space radiobiological effects. For mono-energetic beams, the code evaluates the linear-energy transfer (LET), range (R), and absorption in tissue equivalent material for a given Charge (Z), Mass Number (A) and kinetic energy (E) of an ion. In addition, a set of biophysical properties are evaluated such as the Poisson distribution of ion or delta-ray hits for a specified cellular area, cell survival curves, and mutation and tumor probabilities. The GERMcode also calculates the radiation transport of the beam line for either a fixed number of user-specified depths or at multiple positions along the Bragg curve of the particle. The contributions from primary ion and nuclear secondaries are evaluated. The GERMcode accounts for the major nuclear interaction processes of importance for describing heavy ion beams, including nuclear fragmentation, elastic scattering, and knockout-cascade processes by using the quantum multiple scattering fragmentation (QMSFRG) model. The QMSFRG model has been shown to be in excellent agreement with available experimental data for nuclear fragmentation cross sections, and has been used by the GERMcode for application to thick target experiments. The GERMcode provides scientists participating in NSRL experiments with the data needed for the interpretation of their experiments, including the ability to model the beam line, the shielding of samples and sample holders, and the estimates of basic physical and biological outputs of the designed experiments. We present an overview of the GERMcode GUI, as well as providing training applications.

  2. Development of a GCR Event-based Risk Model

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Ponomarev, Artem L.; Plante, Ianik; Carra, Claudio; Kim, Myung-Hee

    2009-01-01

    A goal at NASA is to develop event-based systems biology models of space radiation risks that will replace the current dose-based empirical models. Complex and varied biochemical signaling processes transmit the initial DNA and oxidative damage from space radiation into cellular and tissue responses. Mis-repaired damage or aberrant signals can lead to genomic instability, persistent oxidative stress or inflammation, which are causative of cancer and CNS risks. Protective signaling through adaptive responses or cell repopulation is also possible. We are developing a computational simulation approach to galactic cosmic ray (GCR) effects that is based on biological events rather than average quantities such as dose, fluence, or dose equivalent. The goal of the GCR Event-based Risk Model (GERMcode) is to provide a simulation tool to describe and integrate physical and biological events into stochastic models of space radiation risks. We used the quantum multiple scattering model of heavy ion fragmentation (QMSFRG) and well known energy loss processes to develop a stochastic Monte-Carlo based model of GCR transport in spacecraft shielding and tissue. We validated the accuracy of the model by comparing to physical data from the NASA Space Radiation Laboratory (NSRL). Our simulation approach allows us to time-tag each GCR proton or heavy ion interaction in tissue including correlated secondary ions often of high multiplicity. Conventional space radiation risk assessment employs average quantities, and assumes linearity and additivity of responses over the complete range of GCR charge and energies. To investigate possible deviations from these assumptions, we studied several biological response pathway models of varying induction and relaxation times including the ATM, TGF -Smad, and WNT signaling pathways. We then considered small volumes of interacting cells and the time-dependent biophysical events that the GCR would produce within these tissue volumes to estimate how GCR event rates mapped to biological signaling induction and relaxation times. We considered several hypotheses related to signaling and cancer risk, and then performed simulations for conditions where aberrant or adaptive signaling would occur on long-duration space mission. Our results do not support the conventional assumptions of dose, linearity and additivity. A discussion on how event-based systems biology models, which focus on biological signaling as the mechanism to propagate damage or adaptation, can be further developed for cancer and CNS space radiation risk projections is given.

  3. GERMcode: A Stochastic Model for Space Radiation Risk Assessment

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; Ponomarev, Artem L.; Cucinotta, Francis A.

    2012-01-01

    A new computer model, the GCR Event-based Risk Model code (GERMcode), was developed to describe biophysical events from high-energy protons and high charge and energy (HZE) particles that have been studied at the NASA Space Radiation Laboratory (NSRL) for the purpose of simulating space radiation biological effects. In the GERMcode, the biophysical description of the passage of HZE particles in tissue and shielding materials is made with a stochastic approach that includes both particle track structure and nuclear interactions. The GERMcode accounts for the major nuclear interaction processes of importance for describing heavy ion beams, including nuclear fragmentation, elastic scattering, and knockout-cascade processes by using the quantum multiple scattering fragmentation (QMSFRG) model. The QMSFRG model has been shown to be in excellent agreement with available experimental data for nuclear fragmentation cross sections. For NSRL applications, the GERMcode evaluates a set of biophysical properties, such as the Poisson distribution of particles or delta-ray hits for a given cellular area and particle dose, the radial dose on tissue, and the frequency distribution of energy deposition in a DNA volume. By utilizing the ProE/Fishbowl ray-tracing analysis, the GERMcode will be used as a bi-directional radiation transport model for future spacecraft shielding analysis in support of Mars mission risk assessments. Recent radiobiological experiments suggest the need for new approaches to risk assessment that include time-dependent biological events due to the signaling times for activation and relaxation of biological processes in cells and tissue. Thus, the tracking of the temporal and spatial distribution of events in tissue is a major goal of the GERMcode in support of the simulation of biological processes important in GCR risk assessments. In order to validate our approach, basic radiobiological responses such as cell survival curves, mutation, chromosomal aberrations, and representative mouse tumor induction curves are implemented into the GERMcode. Extension of these descriptions to other endpoints related to non-targeted effects and biochemical pathway responses will be discussed.

  4. Overview of the Graphical User Interface for the GERM Code (GCR Event-Based Risk Model

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee; Cucinotta, Francis A.

    2010-01-01

    The descriptions of biophysical events from heavy ions are of interest in radiobiology, cancer therapy, and space exploration. The biophysical description of the passage of heavy ions in tissue and shielding materials is best described by a stochastic approach that includes both ion track structure and nuclear interactions. A new computer model called the GCR Event-based Risk Model (GERM) code was developed for the description of biophysical events from heavy ion beams at the NASA Space Radiation Laboratory (NSRL). The GERM code calculates basic physical and biophysical quantities of high-energy protons and heavy ions that have been studied at NSRL for the purpose of simulating space radiobiological effects. For mono-energetic beams, the code evaluates the linear-energy transfer (LET), range (R), and absorption in tissue equivalent material for a given Charge (Z), Mass Number (A) and kinetic energy (E) of an ion. In addition, a set of biophysical properties are evaluated such as the Poisson distribution of ion or delta-ray hits for a specified cellular area, cell survival curves, and mutation and tumor probabilities. The GERM code also calculates the radiation transport of the beam line for either a fixed number of user-specified depths or at multiple positions along the Bragg curve of the particle. The contributions from primary ion and nuclear secondaries are evaluated. The GERM code accounts for the major nuclear interaction processes of importance for describing heavy ion beams, including nuclear fragmentation, elastic scattering, and knockout-cascade processes by using the quantum multiple scattering fragmentation (QMSFRG) model. The QMSFRG model has been shown to be in excellent agreement with available experimental data for nuclear fragmentation cross sections, and has been used by the GERM code for application to thick target experiments. The GERM code provides scientists participating in NSRL experiments with the data needed for the interpretation of their experiments, including the ability to model the beam line, the shielding of samples and sample holders, and the estimates of basic physical and biological outputs of the designed experiments. We present an overview of the GERM code GUI, as well as providing training applications.

  5. Mixed-field GCR Simulations for Radiobiological Research using Ground Based Accelerators

    NASA Astrophysics Data System (ADS)

    Kim, Myung-Hee Y.; Rusek, Adam; Cucinotta, Francis

    Space radiation is comprised of a large number of particle types and energies, which have differential ionization power from high energy protons to high charge and energy (HZE) particles and secondary neutrons produced by galactic cosmic rays (GCR). Ground based accelerators such as the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL) are used to simulate space radiation for radiobiology research and dosimetry, electronics parts, and shielding testing using mono-energetic beams for single ion species. As a tool to support research on new risk assessment models, we have developed a stochastic model of heavy ion beams and space radiation effects, the GCR Event-based Risk Model computer code (GERMcode). For radiobiological research on mixed-field space radiation, a new GCR simulator at NSRL is proposed. The NSRL-GCR simulator, which implements the rapid switching mode and the higher energy beam extraction to 1.5 GeV/u, can integrate multiple ions into a single simulation to create GCR Z-spectrum in major energy bins. After considering the GCR environment and energy limitations of NSRL, a GCR reference field is proposed after extensive simulation studies using the GERMcode. The GCR reference field is shown to reproduce the Z and LET spectra of GCR behind shielding within 20 percents accuracy compared to simulated full GCR environments behind shielding. A major challenge for space radiobiology research is to consider chronic GCR exposure of up to 3-years in relation to simulations with cell and animal models of human risks. We discuss possible approaches to map important biological time scales in experimental models using ground-based simulation with extended exposure of up to a few weeks and fractionation approaches at a GCR simulator.

  6. Mixed-field GCR Simulations for Radiobiological Research Using Ground Based Accelerators

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; Rusek, Adam; Cucinotta, Francis A.

    2014-01-01

    Space radiation is comprised of a large number of particle types and energies, which have differential ionization power from high energy protons to high charge and energy (HZE) particles and secondary neutrons produced by galactic cosmic rays (GCR). Ground based accelerators such as the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL) are used to simulate space radiation for radiobiology research and dosimetry, electronics parts, and shielding testing using mono-energetic beams for single ion species. As a tool to support research on new risk assessment models, we have developed a stochastic model of heavy ion beams and space radiation effects, the GCR Event-based Risk Model computer code (GERMcode). For radiobiological research on mixed-field space radiation, a new GCR simulator at NSRL is proposed. The NSRL-GCR simulator, which implements the rapid switching mode and the higher energy beam extraction to 1.5 GeV/u, can integrate multiple ions into a single simulation to create GCR Z-spectrum in major energy bins. After considering the GCR environment and energy limitations of NSRL, a GCR reference field is proposed after extensive simulation studies using the GERMcode. The GCR reference field is shown to reproduce the Z and LET spectra of GCR behind shielding within 20% accuracy compared to simulated full GCR environments behind shielding. A major challenge for space radiobiology research is to consider chronic GCR exposure of up to 3-years in relation to simulations with cell and animal models of human risks. We discuss possible approaches to map important biological time scales in experimental models using ground-based simulation with extended exposure of up to a few weeks and fractionation approaches at a GCR simulator.

  7. GCR Environmental Models I: Sensitivity Analysis for GCR Environments

    NASA Technical Reports Server (NTRS)

    Slaba, Tony C.; Blattnig, Steve R.

    2014-01-01

    Accurate galactic cosmic ray (GCR) models are required to assess crew exposure during long-duration missions to the Moon or Mars. Many of these models have been developed and compared to available measurements, with uncertainty estimates usually stated to be less than 15%. However, when the models are evaluated over a common epoch and propagated through to effective dose, relative differences exceeding 50% are observed. This indicates that the metrics used to communicate GCR model uncertainty can be better tied to exposure quantities of interest for shielding applications. This is the first of three papers focused on addressing this need. In this work, the focus is on quantifying the extent to which each GCR ion and energy group, prior to entering any shielding material or body tissue, contributes to effective dose behind shielding. Results can be used to more accurately calibrate model-free parameters and provide a mechanism for refocusing validation efforts on measurements taken over important energy regions. Results can also be used as references to guide future nuclear cross-section measurements and radiobiology experiments. It is found that GCR with Z>2 and boundary energies below 500 MeV/n induce less than 5% of the total effective dose behind shielding. This finding is important given that most of the GCR models are developed and validated against Advanced Composition Explorer/Cosmic Ray Isotope Spectrometer (ACE/CRIS) measurements taken below 500 MeV/n. It is therefore possible for two models to very accurately reproduce the ACE/CRIS data while inducing very different effective dose values behind shielding.

  8. Nuclear interactions in heavy ion transport and event-based risk models.

    PubMed

    Cucinotta, Francis A; Plante, Ianik; Ponomarev, Artem L; Kim, Myung-Hee Y

    2011-02-01

    The physical description of the passage of heavy ions in tissue and shielding materials is of interest in radiobiology, cancer therapy and space exploration, including a human mission to Mars. Galactic cosmic rays (GCRs) consist of a large number of ion types and energies. Energy loss processes occur continuously along the path of heavy ions and are well described by the linear energy transfer (LET), straggling and multiple scattering algorithms. Nuclear interactions lead to much larger energy deposition than atomic-molecular collisions and alter the composition of heavy ion beams while producing secondary nuclei often in high multiplicity events. The major nuclear interaction processes of importance for describing heavy ion beams was reviewed, including nuclear fragmentation, elastic scattering and knockout-cascade processes. The quantum multiple scattering fragmentation model is shown to be in excellent agreement with available experimental data for nuclear fragmentation cross sections and is studied for application to thick target experiments. A new computer model, which was developed for the description of biophysical events from heavy ion beams at the NASA Space Radiation Laboratory (NSRL), called the GCR Event Risk-Based Model (GERMcode) is described. PMID:21242169

  9. Isotopic Dependence of GCR Fluence behind Shielding

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Wilson, John W.; Saganti, Premkumar; Kim, Myung-Hee Y.; Cleghorn, Timothy; Zeitlin, Cary; Tripathi, Ram K.

    2006-01-01

    In this paper we consider the effects of the isotopic composition of the primary galactic cosmic rays (GCR), nuclear fragmentation cross-sections, and isotopic-grid on the solution to transport models used for shielding studies. Satellite measurements are used to describe the isotopic composition of the GCR. For the nuclear interaction data-base and transport solution, we use the quantum multiple-scattering theory of nuclear fragmentation (QMSFRG) and high-charge and energy (HZETRN) transport code, respectively. The QMSFRG model is shown to accurately describe existing fragmentation data including proper description of the odd-even effects as function of the iso-spin dependence on the projectile nucleus. The principle finding of this study is that large errors (+/-100%) will occur in the mass-fluence spectra when comparing transport models that use a complete isotopic-grid (approx.170 ions) to ones that use a reduced isotopic-grid, for example the 59 ion-grid used in the HZETRN code in the past, however less significant errors (<+/-20%) occur in the elemental-fluence spectra. Because a complete isotopic-grid is readily handled on small computer workstations and is needed for several applications studying GCR propagation and scattering, it is recommended that they be used for future GCR studies.

  10. GCR Environmental Models III: GCR Model Validation and Propagated Uncertainties in Effective Dose

    NASA Technical Reports Server (NTRS)

    Slaba, Tony C.; Xu, Xiaojing; Blattnig, Steve R.; Norman, Ryan B.

    2014-01-01

    This is the last of three papers focused on quantifying the uncertainty associated with galactic cosmic rays (GCR) models used for space radiation shielding applications. In the first paper, it was found that GCR ions with Z>2 and boundary energy below 500 MeV/nucleon induce less than 5% of the total effective dose behind shielding. This is an important finding since GCR model development and validation have been heavily biased toward Advanced Composition Explorer/Cosmic Ray Isotope Spectrometer measurements below 500 MeV/nucleon. Weights were also developed that quantify the relative contribution of defined GCR energy and charge groups to effective dose behind shielding. In the second paper, it was shown that these weights could be used to efficiently propagate GCR model uncertainties into effective dose behind shielding. In this work, uncertainties are quantified for a few commonly used GCR models. A validation metric is developed that accounts for measurements uncertainty, and the metric is coupled to the fast uncertainty propagation method. For this work, the Badhwar-O'Neill (BON) 2010 and 2011 and the Matthia GCR models are compared to an extensive measurement database. It is shown that BON2011 systematically overestimates heavy ion fluxes in the range 0.5-4 GeV/nucleon. The BON2010 and BON2011 also show moderate and large errors in reproducing past solar activity near the 2000 solar maximum and 2010 solar minimum. It is found that all three models induce relative errors in effective dose in the interval [-20%, 20%] at a 68% confidence level. The BON2010 and Matthia models are found to have similar overall uncertainty estimates and are preferred for space radiation shielding applications.

  11. GCR environmental models III: GCR model validation and propagated uncertainties in effective dose

    NASA Astrophysics Data System (ADS)

    Slaba, Tony C.; Xu, Xiaojing; Blattnig, Steve R.; Norman, Ryan B.

    2014-04-01

    This is the last of three papers focused on quantifying the uncertainty associated with galactic cosmic rays (GCR) models used for space radiation shielding applications. In the first paper, it was found that GCR ions with Z > 2 and boundary energy below 500 MeV/nucleon induce less than 5% of the total effective dose behind shielding. This is an important finding since GCR model development and validation have been heavily biased toward Advanced Composition Explorer/Cosmic Ray Isotope Spectrometer measurements below 500 MeV/nucleon. Weights were also developed that quantify the relative contribution of defined GCR energy and charge groups to effective dose behind shielding. In the second paper, it was shown that these weights could be used to efficiently propagate GCR model uncertainties into effective dose behind shielding. In this work, uncertainties are quantified for a few commonly used GCR models. A validation metric is developed that accounts for measurements uncertainty, and the metric is coupled to the fast uncertainty propagation method. For this work, the Badhwar-O'Neill (BON) 2010 and 2011 and the Matthia GCR models are compared to an extensive measurement database. It is shown that BON2011 systematically overestimates heavy ion fluxes in the range 0.5-4 GeV/nucleon. The BON2010 and BON2011 also show moderate and large errors in reproducing past solar activity near the 2000 solar maximum and 2010 solar minimum. It is found that all three models induce relative errors in effective dose in the interval [-20%, 20%] at a 68% confidence level. The BON2010 and Matthia models are found to have similar overall uncertainty estimates and are preferred for space radiation shielding applications.

  12. Isotopic Effects in Nuclear Fragmentation and GCR Transport Problems

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.

    2002-01-01

    Improving the accuracy of the galactic cosmic ray (GCR) environment and transport models is an important goal in preparing for studies of the projected risks and the efficiency of potential mitigations methods for space exploration. In this paper we consider the effects of the isotopic composition of the primary cosmic rays and the isotopic dependence of nuclear fragmentation cross sections on GCR transport models. Measurements are used to describe the isotopic composition of the GCR including their modulation throughout the solar cycle. The quantum multiple-scattering approach to nuclear fragmentation (QMSFRG) is used as the data base generator in order to accurately describe the odd-even effect in fragment production. Using the Badhwar and O'Neill GCR model, the QMSFRG model and the HZETRN transport code, the effects of the isotopic dependence of the primary GCR composition and on fragment production for transport problems is described for a complete GCR isotopic-grid. The principle finding of this study is that large errors ( 100%) will occur in the mass-flux spectra when comparing the complete isotopic-grid (141 ions) to a reduced isotopic-grid (59 ions), however less significant errors 30%) occur in the elemental-flux spectra. Because the full isotopic-grid is readily handled on small computer work-stations, it is recommended that they be used for future GCR studies.

  13. Impact of AMS-02 Measurements on Reducing GCR Model Uncertainties

    NASA Technical Reports Server (NTRS)

    Slaba, T. C.; O'Neill, P. M.; Golge, S.; Norbury, J. W.

    2015-01-01

    For vehicle design, shield optimization, mission planning, and astronaut risk assessment, the exposure from galactic cosmic rays (GCR) poses a significant and complex problem both in low Earth orbit and in deep space. To address this problem, various computational tools have been developed to quantify the exposure and risk in a wide range of scenarios. Generally, the tool used to describe the ambient GCR environment provides the input into subsequent computational tools and is therefore a critical component of end-to-end procedures. Over the past few years, several researchers have independently and very carefully compared some of the widely used GCR models to more rigorously characterize model differences and quantify uncertainties. All of the GCR models studied rely heavily on calibrating to available near-Earth measurements of GCR particle energy spectra, typically over restricted energy regions and short time periods. In this work, we first review recent sensitivity studies quantifying the ions and energies in the ambient GCR environment of greatest importance to exposure quantities behind shielding. Currently available measurements used to calibrate and validate GCR models are also summarized within this context. It is shown that the AMS-II measurements will fill a critically important gap in the measurement database. The emergence of AMS-II measurements also provides a unique opportunity to validate existing models against measurements that were not used to calibrate free parameters in the empirical descriptions. Discussion is given regarding rigorous approaches to implement the independent validation efforts, followed by recalibration of empirical parameters.

  14. Event-based visual flow.

    PubMed

    Benosman, Ryad; Clercq, Charles; Lagorce, Xavier; Ieng, Sio-Hoi; Bartolozzi, Chiara

    2014-02-01

    This paper introduces a new methodology to compute dense visual flow using the precise timings of spikes from an asynchronous event-based retina. Biological retinas, and their artificial counterparts, are totally asynchronous and data-driven and rely on a paradigm of light acquisition radically different from most of the currently used frame-grabber technologies. This paper introduces a framework to estimate visual flow from the local properties of events' spatiotemporal space. We will show that precise visual flow orientation and amplitude can be estimated using a local differential approach on the surface defined by coactive events. Experimental results are presented; they show the method adequacy with high data sparseness and temporal resolution of event-based acquisition that allows the computation of motion flow with microsecond accuracy and at very low computational cost. PMID:24807038

  15. A Stochastic Model of Space Radiation Transport as a Tool in the Development of Time-Dependent Risk Assessment

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; Nounu, Hatem N.; Ponomarev, Artem L.; Cucinotta, Francis A.

    2011-01-01

    A new computer model, the GCR Event-based Risk Model code (GERMcode), was developed to describe biophysical events from high-energy protons and heavy ions that have been studied at the NASA Space Radiation Laboratory (NSRL) [1] for the purpose of simulating space radiation biological effects. In the GERMcode, the biophysical description of the passage of heavy ions in tissue and shielding materials is made with a stochastic approach that includes both ion track structure and nuclear interactions. The GERMcode accounts for the major nuclear interaction processes of importance for describing heavy ion beams, including nuclear fragmentation, elastic scattering, and knockout-cascade processes by using the quantum multiple scattering fragmentation (QMSFRG) model [2]. The QMSFRG model has been shown to be in excellent agreement with available experimental data for nuclear fragmentation cross sections

  16. Host Event Based Network Monitoring

    SciTech Connect

    Jonathan Chugg

    2013-01-01

    The purpose of INL’s research on this project is to demonstrate the feasibility of a host event based network monitoring tool and the effects on host performance. Current host based network monitoring tools work on polling which can miss activity if it occurs between polls. Instead of polling, a tool could be developed that makes use of event APIs in the operating system to receive asynchronous notifications of network activity. Analysis and logging of these events will allow the tool to construct the complete real-time and historical network configuration of the host while the tool is running. This research focused on three major operating systems commonly used by SCADA systems: Linux, WindowsXP, and Windows7. Windows 7 offers two paths that have minimal impact on the system and should be seriously considered. First is the new Windows Event Logging API, and, second, Windows 7 offers the ALE API within WFP. Any future work should focus on these methods.

  17. Study of laser nitriding on the GCR15 steel surface

    NASA Astrophysics Data System (ADS)

    Gan, Wu; Rui, Wang; Jang-Ping, Yang; Xue-Kang, Chen; Sheng-Zhu, Cao; Wan-Tu, Guo; Kai-Wen, Shang; Bo, Wei; Xiao-Yi, Wang; Lan-Xi, Wang

    Pulse laser nitriding of GCr15 steel in the surrounding of NH3 gas was studied. The experimental results show that a high hardness, good wear resistance, compact and uniformity hard layer of iron nitride was obtained. The results of micro-hardness and wear rate testing shows that after laser nitriding, the micro-hardness of the sample increased 18 percent and wear rate of the sample decreased 50 percent, laser nitriding improves the sample's wear resistance character. The nitriding layer is about 150 μm thick and contains nitrided iron dendrites. The microstructure, phase constitution, micro-hardness, depth and wear character of the nitriding layer were determined and analyzed, and the pulsed laser nitride mechanism on the surface of GCr15 steel was discussed.

  18. Asynchronous frameless event-based optical flow.

    PubMed

    Benosman, Ryad; Ieng, Sio-Hoi; Clercq, Charles; Bartolozzi, Chiara; Srinivasan, Mandyam

    2012-03-01

    This paper introduces a process to compute optical flow using an asynchronous event-based retina at high speed and low computational load. A new generation of artificial vision sensors has now started to rely on biologically inspired designs for light acquisition. Biological retinas, and their artificial counterparts, are totally asynchronous and data driven and rely on a paradigm of light acquisition radically different from most of the currently used frame-grabber technologies. This paper introduces a framework for processing visual data using asynchronous event-based acquisition, providing a method for the evaluation of optical flow. The paper shows that current limitations of optical flow computation can be overcome by using event-based visual acquisition, where high data sparseness and high temporal resolution permit the computation of optical flow with micro-second accuracy and at very low computational cost. PMID:22154354

  19. Event-based control for memristive systems

    NASA Astrophysics Data System (ADS)

    Wen, Shiping; Zeng, Zhigang; Huang, Tingwen

    2014-10-01

    This paper studies the event-based control for memristive systems. Consider the state-dependent properties of the memristor, a new fuzzy model employing parallel distributed compensation (PDC) gives a new way to linearize complicated memristive system with only two subsystems. As the existence of uncertainties of memristor and to reduce the amount of communication, event-based control algorithm to stabilize memristive systems and extend the results to systems with signal quantization and networked induced delays. Through the fuzzy modeling and distributed event-based control, there are three main advantages: (1) only two linear subsystems are considered to reduce the numbers of fuzzy rules from 2n to 2×n as for traditional Takagi-Sugeno fuzzy model, n is the number of memristive subsystems; (2) the memristive subsystem is triggered at its own event time, which reduces communication burdens and lowers the controller updating frequency; (3) the effects of quantization and time delays are taken into account.

  20. The Role of Gcr1p in the Transcriptional Activation of Glycolytic Genes in Yeast Saccharomyces Cerevisiae

    PubMed Central

    Uemura, H.; Koshio, M.; Inoue, Y.; Lopez, M. C.; Baker, H. V.

    1997-01-01

    To study the interdependence of Gcr1p and Rap1p, we prepared a series of synthetic regulatory sequences that contained various numbers and combinations of CT-boxes (Gcr1p-binding sites) and RPG-boxes (Rap1p-binding sites). The ability of the synthetic oligonucleotides to function as regulatory sequences was tested using an ENO1-lacZ reporter gene. As observed previously, synthetic oligonucleotides containing both CT- and RPG-boxes conferred strong UAS activity. Likewise, a lone CT-box did not show any UAS activity. By contrast, oligonucleotides containing tandem CT-boxes but no RPG-box conferred strong promoter activity. This UAS activity was not dependent on position or orientation of the oligonucleotides in the 5' noncoding region. However, it was dependent on both GCR1 and GCR2. These results suggest that the ability of Gcr1p to bind Gcr1p-binding sites in vivo is not absolutely dependent on Rap1p. Eleven independent mutants of GCR1 were isolated that conferred weak UAS activity to a single CT-box. Five mutants had single mutations in Gcr1p's DNA-binding domain and displayed slightly higher affinity for the CT-box. These results support the hypothesis that Gcr1p and Gcr2p play the central role in glycolytic gene expression and that the function of Rap1p is to facilitate the binding of Gcr1p to its target. PMID:9335590

  1. Asynchronous event-based hebbian epipolar geometry.

    PubMed

    Benosman, Ryad; Ieng, Sio-Hoï; Rogister, Paul; Posch, Christoph

    2011-11-01

    Epipolar geometry, the cornerstone of perspective stereo vision, has been studied extensively since the advent of computer vision. Establishing such a geometric constraint is of primary importance, as it allows the recovery of the 3-D structure of scenes. Estimating the epipolar constraints of nonperspective stereo is difficult, they can no longer be defined because of the complexity of the sensor geometry. This paper will show that these limitations are, to some extent, a consequence of the static image frames commonly used in vision. The conventional frame-based approach suffers from a lack of the dynamics present in natural scenes. We introduce the use of neuromorphic event-based--rather than frame-based--vision sensors for perspective stereo vision. This type of sensor uses the dimension of time as the main conveyor of information. In this paper, we present a model for asynchronous event-based vision, which is then used to derive a general new concept of epipolar geometry linked to the temporal activation of pixels. Practical experiments demonstrate the validity of the approach, solving the problem of estimating the fundamental matrix applied, in a first stage, to classic perspective vision and then to more general cameras. Furthermore, this paper shows that the properties of event-based vision sensors allow the exploration of not-yet-defined geometric relationships, finally, we provide a definition of general epipolar geometry deployable to almost any visual sensor. PMID:21954205

  2. Landscape of international event-based biosurveillance

    PubMed Central

    Hartley, DM; Nelson, NP; Walters, R; Arthur, R; Yangarber, R; Madoff, L; Linge, JP; Mawudeku, A; Collier, N; Brownstein, JS; Thinus, G; Lightfoot, N

    2010-01-01

    Event-based biosurveillance is a scientific discipline in which diverse sources of data, many of which are available from the Internet, are characterized prospectively to provide information on infectious disease events. Biosurveillance complements traditional public health surveillance to provide both early warning of infectious disease events and situational awareness. The Global Health Security Action Group of the Global Health Security Initiative is developing a biosurveillance capability that integrates and leverages component systems from member nations. This work discusses these biosurveillance systems and identifies needed future studies. PMID:22460393

  3. On event-based optical flow detection

    PubMed Central

    Brosch, Tobias; Tschechne, Stephan; Neumann, Heiko

    2015-01-01

    Event-based sensing, i.e., the asynchronous detection of luminance changes, promises low-energy, high dynamic range, and sparse sensing. This stands in contrast to whole image frame-wise acquisition by standard cameras. Here, we systematically investigate the implications of event-based sensing in the context of visual motion, or flow, estimation. Starting from a common theoretical foundation, we discuss different principal approaches for optical flow detection ranging from gradient-based methods over plane-fitting to filter based methods and identify strengths and weaknesses of each class. Gradient-based methods for local motion integration are shown to suffer from the sparse encoding in address-event representations (AER). Approaches exploiting the local plane like structure of the event cloud, on the other hand, are shown to be well suited. Within this class, filter based approaches are shown to define a proper detection scheme which can also deal with the problem of representing multiple motions at a single location (motion transparency). A novel biologically inspired efficient motion detector is proposed, analyzed and experimentally validated. Furthermore, a stage of surround normalization is incorporated. Together with the filtering this defines a canonical circuit for motion feature detection. The theoretical analysis shows that such an integrated circuit reduces motion ambiguity in addition to decorrelating the representation of motion related activations. PMID:25941470

  4. Down-regulated Lotus japonicus GCR1 plants exhibit nodulation signalling pathways alteration.

    PubMed

    Rogato, Alessandra; Valkov, Vladimir Totev; Alves, Ludovico Martins; Apone, Fabio; Colucci, Gabriella; Chiurazzi, Maurizio

    2016-06-01

    G Protein Coupled Receptor (GPCRs) are integral membrane proteins involved in various signalling pathways by perceiving many extracellular signals and transducing them to heterotrimeric G proteins, which further transduce these signals to intracellular downstream effectors. GCR1 is the only reliable plant candidate as a member of the GPCRs superfamily. In the legume/rhizobia symbiotic interaction, G proteins are involved in signalling pathways controlling different steps of the nodulation program. In order to investigate the putative hierarchic role played by GCR1 in these symbiotic pathways we identified and characterized the Lotus japonicus gene encoding the seven transmembrane GCR1 protein. The detailed molecular and topological analyses of LjGCR1 expression patterns that are presented suggest a possible involvement in the early steps of nodule organogenesis. Furthermore, phenotypic analyses of independent transgenic RNAi lines, showing a significant LjGCR1 expression down regulation, suggest an epistatic action in the control of molecular markers of nodulation pathways, although no macroscopic symbiotic phenotypes could be revealed. PMID:27095401

  5. Effect of Implantation Sequence on Tribological Behavior of GCr15 Steel by PBII

    NASA Astrophysics Data System (ADS)

    Gu, Le; Zhou, Hui; Cao, Guojian; Tang, Guangze; Ma, Xinxin; Wang, Liqin

    2016-05-01

    In the present work, the effect of implantation sequence on tribological behavior of GCr15 steel treated by plasma-based ion implantation of carbon and nitrogen has been investigated. The treated GCr15 steels were characterized for microstructure and abrasive wear performance through combination of Raman spectroscopy, nano-indentation, and wear tests. Raman spectroscopy indicated that diamond-like carbon (DLC) films were formed after implantation of carbon with or without implantation of nitrogen, and the implantation of nitrogen after the implantation of carbon destroyed the graphite structure of the DLC films. The nano-indentation and wear tests showed that nanohardness as well as wear resistance of the GCr15 steel treated with the implantation sequence of nitrogen-carbon was better than those with the implantation sequence of carbon-nitrogen. Meanwhile, the properties were improved with increasing of carbon ion fluence.

  6. Flexible gray component replacement (GCR) based on CIE L*a*b*

    NASA Astrophysics Data System (ADS)

    Ogatsu, Hitoshi; Murai, Kazumasa; Kita, Shinji

    1995-04-01

    To improve the color fidelity of 4 color reproduction and to increase the flexibility of Gray Component Replacement (GCR) for the text and continuous images, a novel GCR algorithm based on CIE L*a*b* signals is proposed. The algorithm consist of (1) maximum (achromatic) black determination part, (2) black adjustment part based on chroma, and (3) 3 color determination part. On this configuration, black signal is determined ahead of MCY signals, and the freedom of 3 input i.e L*a*b* 4 output i.e. CMYBk conversion is concentrated in (2). By using xerographic color printer, by neural network technique for resolving this, the algorithm is examined. As a result, it is shown that the algorithm can conserve the color fidelity in any GCR rate, and which is applicable on both of text and continuous images.

  7. Effect of Implantation Sequence on Tribological Behavior of GCr15 Steel by PBII

    NASA Astrophysics Data System (ADS)

    Gu, Le; Zhou, Hui; Cao, Guojian; Tang, Guangze; Ma, Xinxin; Wang, Liqin

    2016-04-01

    In the present work, the effect of implantation sequence on tribological behavior of GCr15 steel treated by plasma-based ion implantation of carbon and nitrogen has been investigated. The treated GCr15 steels were characterized for microstructure and abrasive wear performance through combination of Raman spectroscopy, nano-indentation, and wear tests. Raman spectroscopy indicated that diamond-like carbon (DLC) films were formed after implantation of carbon with or without implantation of nitrogen, and the implantation of nitrogen after the implantation of carbon destroyed the graphite structure of the DLC films. The nano-indentation and wear tests showed that nanohardness as well as wear resistance of the GCr15 steel treated with the implantation sequence of nitrogen-carbon was better than those with the implantation sequence of carbon-nitrogen. Meanwhile, the properties were improved with increasing of carbon ion fluence.

  8. Posttranscriptional Regulation of Gcr1 Expression and Activity Is Crucial for Metabolic Adjustment in Response to Glucose Availability.

    PubMed

    Hossain, Munshi Azad; Claggett, Julia M; Edwards, Samantha R; Shi, Aishan; Pennebaker, Sara L; Cheng, Melodyanne Y; Hasty, Jeff; Johnson, Tracy L

    2016-05-01

    The transcription factor Gcr1 controls expression of over 75% of the genes in actively growing yeast. Yet despite its widespread effects, regulation of Gcr1 itself remains poorly understood. Here, we show that posttranscriptional Gcr1 regulation is nutrient dependent. Moreover, GCR1 RNA contains a long, highly conserved intron, which allows the cell to generate multiple RNA and protein isoforms whose levels change upon glucose depletion. Intriguingly, an isoform generated by intron retention is exported from the nucleus, and its translation is initiated from a conserved, intronic translation start site. Expression of gene products from both the spliced and unspliced RNAs is essential, as cells expressing only one isoform cannot adjust their metabolic program in response to environmental changes. Finally, we show that the Gcr1 proteins form dimers, providing an elegant mechanism by which this one gene, through its regulation, can perform the repertoire of transcriptional activities necessary for fine-tuned environmental response. PMID:27153533

  9. GCR Simulator Reference Field and a Spectral Approach for Laboratory Simulation

    NASA Technical Reports Server (NTRS)

    Slaba, Tony C.; Blattnig, Steve R.; Norbury, John W.; Rusek, Adam; La Tessa, Chiara; Walker, Steven A.

    2015-01-01

    The galactic cosmic ray (GCR) simulator at the NASA Space Radiation Laboratory (NSRL) is intended to deliver the broad spectrum of particles and energies encountered in deep space to biological targets in a controlled laboratory setting. In this work, certain aspects of simulating the GCR environment in the laboratory are discussed. Reference field specification and beam selection strategies at NSRL are the main focus, but the analysis presented herein may be modified for other facilities. First, comparisons are made between direct simulation of the external, free space GCR field and simulation of the induced tissue field behind shielding. It is found that upper energy constraints at NSRL limit the ability to simulate the external, free space field directly (i.e. shielding placed in the beam line in front of a biological target and exposed to a free space spectrum). Second, variation in the induced tissue field associated with shielding configuration and solar activity is addressed. It is found that the observed variation is likely within the uncertainty associated with representing any GCR reference field with discrete ion beams in the laboratory, given current facility constraints. A single reference field for deep space missions is subsequently identified. Third, an approach for selecting beams at NSRL to simulate the designated reference field is presented. Drawbacks of the proposed methodology are discussed and weighed against alternative simulation strategies. The neutron component and track structure characteristics of the simulated field are discussed in this context.

  10. Reference field specification and preliminary beam selection strategy for accelerator-based GCR simulation.

    PubMed

    Slaba, Tony C; Blattnig, Steve R; Norbury, John W; Rusek, Adam; La Tessa, Chiara

    2016-02-01

    The galactic cosmic ray (GCR) simulator at the NASA Space Radiation Laboratory (NSRL) is intended to deliver the broad spectrum of particles and energies encountered in deep space to biological targets in a controlled laboratory setting. In this work, certain aspects of simulating the GCR environment in the laboratory are discussed. Reference field specification and beam selection strategies at NSRL are the main focus, but the analysis presented herein may be modified for other facilities and possible biological considerations. First, comparisons are made between direct simulation of the external, free space GCR field and simulation of the induced tissue field behind shielding. It is found that upper energy constraints at NSRL limit the ability to simulate the external, free space field directly (i.e. shielding placed in the beam line in front of a biological target and exposed to a free space spectrum). Second, variation in the induced tissue field associated with shielding configuration and solar activity is addressed. It is found that the observed variation is likely within the uncertainty associated with representing any GCR reference field with discrete ion beams in the laboratory, given current facility constraints. A single reference field for deep space missions is subsequently identified. Third, a preliminary approach for selecting beams at NSRL to simulate the designated reference field is presented. This approach is not a final design for the GCR simulator, but rather a single step within a broader design strategy. It is shown that the beam selection methodology is tied directly to the reference environment, allows facility constraints to be incorporated, and may be adjusted to account for additional constraints imposed by biological or animal care considerations. The major biology questions are not addressed herein but are discussed in a companion paper published in the present issue of this journal. Drawbacks of the proposed methodology are discussed and weighed against alternative simulation strategies. PMID:26948013

  11. Transcriptome Analysis of Arabidopsis GCR1 Mutant Reveals Its Roles in Stress, Hormones, Secondary Metabolism and Phosphate Starvation

    PubMed Central

    Chakraborty, Navjyoti; Sharma, Priyanka; Kanyuka, Kostya; Pathak, Ravi R.; Choudhury, Devapriya; Hooley, Richard A.; Raghuram, Nandula

    2015-01-01

    The controversy over the existence or the need for G-protein coupled receptors (GPCRs) in plant G-protein signalling has overshadowed a more fundamental quest for the role of AtGCR1, the most studied and often considered the best candidate for GPCR in plants. Our whole transcriptome microarray analysis of the GCR1-knock-out mutant (gcr1-5) in Arabidopsis thaliana revealed 350 differentially expressed genes spanning all chromosomes. Many of them were hitherto unknown in the context of GCR1 or G-protein signalling, such as in phosphate starvation, storage compound and fatty acid biosynthesis, cell fate, etc. We also found some GCR1-responsive genes/processes that are reported to be regulated by heterotrimeric G-proteins, such as biotic and abiotic stress, hormone response and secondary metabolism. Thus, GCR1 could have G-protein-mediated as well as independent roles and regardless of whether it works as a GPCR, further analysis of the organism-wide role of GCR1 has a significance of its own. PMID:25668726

  12. Effect of Ultrasonic Treatment on the Solidification Microstructure of GCr15 Bearing Steel

    NASA Astrophysics Data System (ADS)

    Wang, Jianjun; Shi, Xiaofang; Chang, Lizhong; Wang, Haijun; Meng, Lipeng

    2016-02-01

    Ultrasonic treatment with various powers is introduced to liquid steel from the side wall of a mold during GCr15 steel solidification, and the effect of ultrasonic on the microstructure and properties of GCr15 steel is investigated. Results show that the columnar grains in the GCr15 steel are coarse and that the microstructure is inhomogeneous when ultrasonic is not applied on the liquid steel. A suitable power ultrasonic leads to the appearance of a large number of equiaxed grains and increases the uniformity of the microstructure. The segregation of alloy elements gradually decreases as the power increases from 0 W to 500 W. The maximum segregations of carbon and silicon decrease from 2.541 to 1.129 and 2.861 to 1.196, respectively. Given a power of 500 W, the statistical segregations of carbon and silicon decrease from 0.0964 to 0.0693 and 0.1152 to 0.1075, respectively. A further increase in ultrasonic power is not conducive for improving the element segregation. Ultrasonic treatment can remarkably refine the size of carbide and increase the uniformity of its distribution. When the powers are 0 W, 300 W, 500 W, 700 W, and 1,000 W, the average sizes of carbide are 14.63 μm, 2.96 μm, 3.05 μm, 3.72 μm, and 7.83 μm, respectively. The tensile strength, yield strength, and ductility and reduction of the area of the GCr15 bearing steel are correspondingly improved to varying degrees.

  13. Study of Static Recrystallization Behaviors of GCr15 Steel Under Two-Pass Hot Compression Deformation

    NASA Astrophysics Data System (ADS)

    Mao, Huajie; Zhang, Rui; Hua, Lin; Yin, Fei

    2015-02-01

    In order to study the static recrystallization behavior of GCr15 steel during hot deformation process, two-pass hot compression experiments were conducted on Gleeble-3500 thermo-simulation system at the test temperatures from 850 to 1150 °C strain rate from 0.01 to 1 s-1, strain from 0.05 to 0.15 and inter-stage delay time from 1 to 100 s, respectively. The effects of temperature, strain rate and strain on static recrystallization of GCr15 steel were discussed in details. And the kinetic equations, in which the tension-time index n was 0.35 and the activation energy Q was 225.86 kJ/mol, were proposed. The comparison between the experimental results and predicted results was performed and the research results indicated that the effects of deformation parameters on the static recrystallization in multi-stage hot deformation are significant. The predicted results are in good agreement with the experimental ones, which indicates that the proposed kinetic equations can give an accurate estimate of the static recrystallization behaviors and microstructural evolutions for GCr15 steel.

  14. HZETRN: neutron and proton production in quasi-elastic scattering of GCR heavy-ions

    NASA Technical Reports Server (NTRS)

    Shavers, M. R.; Cucinotta, F. A.; Wilson, J. W.

    2001-01-01

    The development of transport models for radiation shielding design and evaluation has provided a series of deterministic computer codes that describe galactic cosmic radiation (GCR), solar particle events, and experimental beams at particle accelerators. These codes continue to be modified to accommodate new theory and improvements to the particle interaction database (Cucinotta et al., 1994, NASA Technical Paper 3472, US Government Printing Office, Washington DC). The solution employed by the heavy-ion transport code HZETRN was derived with the assumption that nuclear fragments are emitted with the same velocity as the incident ion through velocity conserving nuclear interactions. This paper presents a version of the HZETRN transport code that provides a more realistic distribution of the energy of protons and neutrons emitted from GCR interactions in shields. This study shows that the expected GCR dose equivalent is lower than previously calculated for water shields that are less than 110 g cm-2 thick. Calculations of neutron energy spectra in low Earth orbit indicate substantial contributions from relativistic neutrons. c2001 Elsevier Science Ltd. All rights reseved.

  15. On the mechanisms forming the GCR intensity distribution in the heliosphere

    NASA Astrophysics Data System (ADS)

    Krainev, Mikhail

    Recently we draw a conclusion based on solving the boundary-value problem for the galactic cosmic ray (GCR) intensity that during the periods of low and intermediate solar activity the contribution to the GCR intensity of the particle drift in the heliospheric magnetic fields (HMF) is much higher than usually believed. This contribution increases as the cosmic ray energy (T) and the heliocentric distance (r) decrease and for the low energy protons (T ≈ 100 MeV) near the Earth around solar minima it comes to ≈ 70% of the total calculated intensity for both HMF polarities. Here we try to reveal and illustrate the physical mechanisms responsible for this effect using the simple model. Note that in this talk we restrict our consideration only to discussion of the mechanisms forming J(r, θ, T) for any moment characterized by some fixed set of the main parameters (the HMF strength, the solar wind velocity, the current sheet tilt, the HMF polarity etc.). How the relative role of different physical processes changes when this main set is changing with time (t) and the calculated GCR intensity J(r, θ, T; t) describes both the sunspot and magnetic cycles is outside of the scope of the talk.

  16. Badhwar-O'Neil 2007 Galactic Cosmic Ray (GCR) Model Using Advanced Composition Explorer (ACE) Measurements for Solar Cycle 23

    NASA Technical Reports Server (NTRS)

    ONeill, P. M.

    2007-01-01

    Advanced Composition Explorer (ACE) satellite measurements of the galactic cosmic ray flux and correlation with the Climax Neutron Monitor count over Solar Cycle 23 are used to update the Badhwar O'Neill Galactic Cosmic Ray (GCR) model.

  17. Characterization of the DNA-binding activity of GCR1: in vivo evidence for two GCR1-binding sites in the upstream activating sequence of TPI of Saccharomyces cerevisiae.

    PubMed Central

    Huie, M A; Scott, E W; Drazinic, C M; Lopez, M C; Hornstra, I K; Yang, T P; Baker, H V

    1992-01-01

    GCR1 gene function is required for high-level glycolytic gene expression in Saccharomyces cerevisiae. Recently, we suggested that the CTTCC sequence motif found in front of many genes encoding glycolytic enzymes lay at the core of the GCR1-binding site. Here we mapped the DNA-binding domain of GCR1 to the carboxy-terminal 154 amino acids of the polypeptide. DNase I protection studies showed that a hybrid MBP-GCR1 fusion protein protected a region of the upstream activating sequence of TPI (UASTPI), which harbored the CTTCC sequence motif, and suggested that the fusion protein might also interact with a region of the UAS that contained the related sequence CATCC. A series of in vivo G methylation protection experiments of the native TPI promoter were carried out with wild-type and gcr1 deletion mutant strains. The G doublets that correspond to the C doublets in each site were protected in the wild-type strain but not in the gcr1 mutant strain. These data demonstrate that the UAS of TPI contains two GCR1-binding sites which are occupied in vivo. Furthermore, adjacent RAP1/GRF1/TUF- and REB1/GRF2/QBP/Y-binding sites in UASTPI were occupied in the backgrounds of both strains. In addition, DNA band-shift assays were used to show that the MBP-GCR1 fusion protein was able to form nucleoprotein complexes with oligonucleotides that contained CTTCC sequence elements found in front of other glycolytic genes, namely, PGK, ENO1, PYK, and ADH1, all of which are dependent on GCR1 gene function for full expression. However, we were unable to detect specific interactions with CTTCC sequence elements found in front of the translational component genes TEF1, TEF2, and CRY1. Taken together, these experiments have allowed us to propose a consensus GCR1-binding site which is 5'-(T/A)N(T/C)N(G/A)NC(T/A)TCC(T/A)N(T/A)(T/A)(T/G)-3'. Images PMID:1588965

  18. Asynchronous visual event-based time-to-contact.

    PubMed

    Clady, Xavier; Clercq, Charles; Ieng, Sio-Hoi; Houseini, Fouzhan; Randazzo, Marco; Natale, Lorenzo; Bartolozzi, Chiara; Benosman, Ryad

    2014-01-01

    Reliable and fast sensing of the environment is a fundamental requirement for autonomous mobile robotic platforms. Unfortunately, the frame-based acquisition paradigm at the basis of main stream artificial perceptive systems is limited by low temporal dynamics and redundant data flow, leading to high computational costs. Hence, conventional sensing and relative computation are obviously incompatible with the design of high speed sensor-based reactive control for mobile applications, that pose strict limits on energy consumption and computational load. This paper introduces a fast obstacle avoidance method based on the output of an asynchronous event-based time encoded imaging sensor. The proposed method relies on an event-based Time To Contact (TTC) computation based on visual event-based motion flows. The approach is event-based in the sense that every incoming event adds to the computation process thus allowing fast avoidance responses. The method is validated indoor on a mobile robot, comparing the event-based TTC with a laser range finder TTC, showing that event-based sensing offers new perspectives for mobile robotics sensing. PMID:24570652

  19. 27-day variation of the GCR intensity based on corrected and uncorrected for geomagnetic disturbances data of neutron monitors

    NASA Astrophysics Data System (ADS)

    Alania, M. V.; Modzelewska, R.; Wawrzynczak, A.; Sdobnov, V. E.; Kravtsova, M. V.

    2015-08-01

    We study 27-day variations of the galactic cosmic ray (GCR) intensity for 2005-2008 period of the solar cycle #23. We use neutron monitors (NMs) data corrected and uncorrected for geomagnetic disturbances. Besides the limited time intervals when the 27-day variations are clearly established, always exist some feeble 27-day variations in the GCR intensity related to the constantly present weak heliolongitudinal asymmetry in the heliosphere. We calculate the amplitudes of the 27-day variation of the GCR intensity based on the NMs data corrected and uncorrected for geomagnetic disturbances. We show that these amplitudes do not differ for NMs with cut-off rigidities smaller than 4-5 GV comparing with NMs of higher cut-off rigidities. Rigidity spectrum of the 27-day variation of the GCR intensity found in the uncorrected data is soft while it is hard in the case of the corrected data. For both cases exists definite tendency of softening the temporal changes of the 27-day variation's rigidity spectrum in period of 2005 to 2008 approaching the minimum of solar activity. We believe that a study of the 27-day variation of the GCR intensity based on the data uncorrected for geomagnetic disturbances should be carried out by NMs with cut-off rigidities smaller than 4-5 GV.

  20. The GCR1 gene encodes a positive transcriptional regulator of the enolase and glyceraldehyde-3-phosphate dehydrogenase gene families in Saccharomyces cerevisiae.

    PubMed Central

    Holland, M J; Yokoi, T; Holland, J P; Myambo, K; Innis, M A

    1987-01-01

    The intracellular concentrations of the polypeptides encoded by the two enolase (ENO1 and ENO2) and three glyceraldehyde-3-phosphate dehydrogenase (TDH1, TDH2, and TDH3) genes were coordinately reduced more than 20-fold in a Saccharomyces cerevisiae strain carrying the gcr1-1 mutation. The steady-state concentration of glyceraldehyde-3-phosphate dehydrogenase mRNA was shown to be approximately 50-fold reduced in the mutant strain. Overexpression of enolase and glyceraldehyde-3-phosphate dehydrogenase in strains carrying multiple copies of either ENO1 or TDH3 was reduced more than 50-fold in strains carrying the gcr1-1 mutation. These results demonstrated that the GCR1 gene encodes a trans-acting factor which is required for efficient and coordinate expression of these glycolytic gene families. The GCR1 gene and the gcr1-1 mutant allele were cloned and sequenced. GCR1 encodes a predicted 844-amino-acid polypeptide; the gcr1-1 allele contains a 1-base-pair insertion mutation at codon 304. A null mutant carrying a deletion of 90% of the GCR1 coding sequence and a URA3 gene insertion was constructed by gene replacement. The phenotype of a strain carrying this null mutation was identical to that of the gcr1-1 mutant strain. Images PMID:3547083

  1. Miniaturized Hollow-Waveguide Gas Correlation Radiometer (GCR) for Trace Gas Detection in the Martian Atmosphere

    NASA Technical Reports Server (NTRS)

    Wilson, Emily L.; Georgieva, E. M.; Melroy, H. R.

    2012-01-01

    Gas correlation radiometry (GCR) has been shown to be a sensitive and versatile method for detecting trace gases in Earth's atmosphere. Here, we present a miniaturized and simplified version of this instrument capable of mapping multiple trace gases and identifying active regions on the Mars surface. Reduction of the size and mass of the GCR instrument has been achieved by implementing a lightweight, 1 mm inner diameter hollow-core optical fiber (hollow waveguide) for the gas correlation cell. Based on a comparison with an Earth orbiting CO2 gas correlation instrument, replacement of the 10 meter mUltipass cell with hollow waveguide of equivalent pathlength reduces the cell mass from approx 150 kg to approx 0.5 kg, and reduces the volume from 1.9 m x 1.3 m x 0.86 m to a small bundle of fiber coils approximately I meter in diameter by 0.05 m in height (mass and volume reductions of >99%). This modular instrument technique can be expanded to include measurements of additional species of interest including nitrous oxide (N2O), hydrogen sulfide (H2S), methanol (CH3OH), and sulfur dioxide (SO2), as well as carbon dioxide (CO2) for a simultaneous measure of mass balance.

  2. GCR-induced Photon Luminescence of the Moon: The Moon as a CR Detector

    NASA Technical Reports Server (NTRS)

    Wilson, Thomas L.; Lee, Kerry; Andersen, Vic

    2007-01-01

    We report on the results of a preliminary study of the GCR-induced photon luminescence of the Moon using the Monte Carlo program FLUKA. The model of the lunar surface is taken to be the chemical composition of soils found at various landing sites during the Apollo and Luna programs, averaged over all such sites to define a generic regolith for the present analysis. This then becomes the target that is bombarded by Galactic Cosmic Rays (GCRs) in FLUKA to determine the photon fluence when there is no sunshine or Earthshine. From the photon fluence we derive the energy spectrum which can be utilized to design an orbiting optical instrument for measuring the GCR-induced luminescence. This is to be distinguished from the gamma-ray spectrum produced by the radioactive decay of its radiogenic constituents lying in the surface and interior. Also, we investigate transient optical flashes from high-energy CRs impacting the lunar surface (boulders and regolith). The goal is to determine to what extent the Moon could be used as a rudimentary CR detector. Meteor impacts on the Moon have been observed for centuries to generate such flashes, so why not CRs?

  3. Comparison of Transport Codes, HZETRN, HETC and FLUKA, Using 1977 GCR Solar Minimum Spectra

    NASA Technical Reports Server (NTRS)

    Heinbockel, John H.; Slaba, Tony C.; Tripathi, Ram K.; Blattnig, Steve R.; Norbury, John W.; Badavi, Francis F.; Townsend, Lawrence W.; Handler, Thomas; Gabriel, Tony A.; Pinsky, Lawrence S.; Reddell, Brandon; Aumann, Aric R.

    2009-01-01

    The HZETRN deterministic radiation transport code is one of several tools developed to analyze the effects of harmful galactic cosmic rays (GCR) and solar particle events (SPE) on mission planning, astronaut shielding and instrumentation. This paper is a comparison study involving the two Monte Carlo transport codes, HETC-HEDS and FLUKA, and the deterministic transport code, HZETRN. Each code is used to transport ions from the 1977 solar minimum GCR spectrum impinging upon a 20 g/cm2 Aluminum slab followed by a 30 g/cm2 water slab. This research is part of a systematic effort of verification and validation to quantify the accuracy of HZETRN and determine areas where it can be improved. Comparisons of dose and dose equivalent values at various depths in the water slab are presented in this report. This is followed by a comparison of the proton fluxes, and the forward, backward and total neutron fluxes at various depths in the water slab. Comparisons of the secondary light ion 2H, 3H, 3He and 4He fluxes are also examined.

  4. Elemental GCR Observations during the 2009-2010 Solar Minimum Period

    NASA Technical Reports Server (NTRS)

    Lave, K. A.; Israel, M. H.; Binns, W. R.; Christian, E. R.; Cummings, A. C.; Davis, A. J.; deNolfo, G. A.; Leske, R. A.; Mewaldt, R. A.; Stone, E. C.; vonRosenvinge, T. T.; Wiedenbeck, M. E.

    2013-01-01

    Using observations from the Cosmic Ray Isotope Spectrometer (CRIS) onboard the Advanced Composition Explorer (ACE), we present new measurements of the galactic cosmic ray (GCR) elemental composition and energy spectra for the species B through Ni in the energy range approx. 50-550 MeV/nucleon during the record setting 2009-2010 solar minimum period. These data are compared with our observations from the 1997-1998 solar minimum period, when solar modulation in the heliosphere was somewhat higher. For these species, we find that the intensities during the 2009-2010 solar minimum were approx. 20% higher than those in the previous solar minimum, and in fact were the highest GCR intensities recorded during the space age. Relative abundances for these species during the two solar minimum periods differed by small but statistically significant amounts, which are attributed to the combination of spectral shape differences between primary and secondary GCRs in the interstellar medium and differences between the levels of solar modulation in the two solar minima. We also present the secondary-to-primary ratios B/C and (Sc+Ti+V)/Fe for both solar minimum periods, and demonstrate that these ratios are reasonably well fit by a simple "leaky-box" galactic transport model that is combined with a spherically symmetric solar modulation model.

  5. Asynchronous event-based corner detection and matching.

    PubMed

    Clady, Xavier; Ieng, Sio-Hoi; Benosman, Ryad

    2015-06-01

    This paper introduces an event-based luminance-free method to detect and match corner events from the output of asynchronous event-based neuromorphic retinas. The method relies on the use of space-time properties of moving edges. Asynchronous event-based neuromorphic retinas are composed of autonomous pixels, each of them asynchronously generating "spiking" events that encode relative changes in pixels' illumination at high temporal resolutions. Corner events are defined as the spatiotemporal locations where the aperture problem can be solved using the intersection of several geometric constraints in events' spatiotemporal spaces. A regularization process provides the required constraints, i.e. the motion attributes of the edges with respect to their spatiotemporal locations using local geometric properties of visual events. Experimental results are presented on several real scenes showing the stability and robustness of the detection and matching. PMID:25828960

  6. Abstracting event-based control models for high autonomy systems

    NASA Technical Reports Server (NTRS)

    Luh, Cheng-Jye; Zeigler, Bernard P.

    1993-01-01

    A high autonomy system needs many models on which to base control, management, design, and other interventions. These models differ in level of abstraction and in formalism. Concepts and tools are needed to organize the models into a coherent whole. The paper deals with the abstraction processes for systematic derivation of related models for use in event-based control. The multifaceted modeling methodology is briefly reviewed. The morphism concepts needed for application to model abstraction are described. A theory for supporting the construction of DEVS models needed for event-based control is then presented. An implemented morphism on the basis of this theory is also described.

  7. Spatiotemporal features for asynchronous event-based data

    PubMed Central

    Lagorce, Xavier; Ieng, Sio-Hoi; Clady, Xavier; Pfeiffer, Michael; Benosman, Ryad B.

    2015-01-01

    Bio-inspired asynchronous event-based vision sensors are currently introducing a paradigm shift in visual information processing. These new sensors rely on a stimulus-driven principle of light acquisition similar to biological retinas. They are event-driven and fully asynchronous, thereby reducing redundancy and encoding exact times of input signal changes, leading to a very precise temporal resolution. Approaches for higher-level computer vision often rely on the reliable detection of features in visual frames, but similar definitions of features for the novel dynamic and event-based visual input representation of silicon retinas have so far been lacking. This article addresses the problem of learning and recognizing features for event-based vision sensors, which capture properties of truly spatiotemporal volumes of sparse visual event information. A novel computational architecture for learning and encoding spatiotemporal features is introduced based on a set of predictive recurrent reservoir networks, competing via winner-take-all selection. Features are learned in an unsupervised manner from real-world input recorded with event-based vision sensors. It is shown that the networks in the architecture learn distinct and task-specific dynamic visual features, and can predict their trajectories over time. PMID:25759637

  8. Kinetic Analysis of the Austenite Grain Growth in GCr15 Steel

    NASA Astrophysics Data System (ADS)

    Yue, Chongxiang; Zhang, Liwen; Liao, Shulun; Gao, Huiju

    2010-02-01

    The growth behavior of austenite grains in GCr15 steel was investigated through the isothermal annealing tests of the steel under different heating temperatures and holding times. The tests were performed on a Gleeble-3800 thermo-mechanical simulation machine. Austenitizing temperatures 1223, 1323, 1373, and 1423 K were chosen, and holding time varied from 0 to 480 s. Experimental results suggest that austenite grains grow gradually with the increase of heating temperature, and holding time has an important effect on the growth of austenite grains. The time exponent for the growth is bigger at higher temperature, and the growth rate decreases with increasing time. On the basis of previous models and experimental results, a mathematical model that can describe the growth behavior of austenite grains in the tested steel under different heating temperatures and holding times was obtained using regression analysis. The predicted grain sizes by the model are in good agreement with measured ones.

  9. Secondary Cosmic Ray Particles Due to GCR Interactions in the Earth's Atmosphere

    SciTech Connect

    Battistoni, G.; Cerutti, F.; Fasso, A.; Ferrari, A.; Garzelli, M.V.; Lantz, M.; Muraro, S. Pinsky, L.S.; Ranft, J.; Roesler, S.; Sala, P.R.; ,

    2009-06-16

    Primary GCR interact with the Earth's atmosphere originating atmospheric showers, thus giving rise to fluxes of secondary particles in the atmosphere. Electromagnetic and hadronic interactions interplay in the production of these particles, whose detection is performed by means of complementary techniques in different energy ranges and at different depths in the atmosphere, down to the Earth's surface. Monte Carlo codes are essential calculation tools which can describe the complexity of the physics of these phenomena, thus allowing the analysis of experimental data. However, these codes are affected by important uncertainties, concerning, in particular, hadronic physics at high energy. In this paper we shall report some results concerning inclusive particle fluxes and atmospheric shower properties as obtained using the FLUKA transport and interaction code. Some emphasis will also be given to the validation of the physics models of FLUKA involved in these calculations.

  10. Microstructure of warm rolling and pearlitic transformation of ultrafine-grained GCr15 steel

    SciTech Connect

    Sun, Jun-Jie; Lian, Fu-Liang; Liu, Hong-Ji; Jiang, Tao; Guo, Sheng-Wu; Du, Lin-Xiu; Liu, Yong-Ning

    2014-09-15

    Pearlitic transformation mechanisms have been investigated in ultra-fine grained GCr15 steel. The ultrafine-grained steel, whose grain size was less than 1 μm, was prepared by thermo-mechanical treatment at 873 K and then annealing at 923 K for 2 h. Pearlitic transformation was conducted by reheating the ultra-fine grained samples at 1073 K and 1123 K for different periods of time and then cooling in air. Scanning electron microscope observation shows that normal lamellar pearlite, instead of granular cementite and ferrite, cannot be formed when the grain size is approximately less than 4(± 0.6) μm, which yields a critical grain size for normal lamellar pearlitic transformations in this chromium alloyed steel. The result confirms that grain size has a great influence on pearlitic transformation by increasing the diffusion rate of carbon atoms in the ultra-fine grained steel, and the addition of chromium element doesn't change this pearlitic phase transformation rule. Meanwhile, the grain growth rate is reduced by chromium alloying, which is beneficial to form fine grains during austenitizing, thus it facilitating pearlitic transformation by divorced eutectoid transformation. Moreover, chromium element can form a relatively high gradient in the frontier of the undissolved carbide, which promotes carbide formation in the frontier of the undissolved carbide, i.e., chromium promotes divorced eutectoid transformation. - Highlights: • Ultrafine-grained GCr15 steel was obtained by warm rolling and annealing technology. • Reduction of grain size makes pearlite morphology from lamellar to granular. • Adding Cr does not change normal pearlitic phase transformation rule in UFG steel. • Cr carbide resists grain growth and facilitates pearlitic transformation by DET.

  11. Mars Science Laboratory; A Model for Event-Based EPO

    NASA Astrophysics Data System (ADS)

    Mayo, Louis; Lewis, E.; Cline, T.; Stephenson, B.; Erickson, K.; Ng, C.

    2012-10-01

    The NASA Mars Science Laboratory (MSL) and its Curiosity Rover, a part of NASA's Mars Exploration Program, represent the most ambitious undertaking to date to explore the red planet. MSL/Curiosity was designed primarily to determine whether Mars ever had an environment capable of supporting microbial life. NASA's MSL education program was designed to take advantage of existing, highly successful event based education programs to communicate Mars science and education themes to worldwide audiences through live webcasts, video interviews with scientists, TV broadcasts, professional development for teachers, and the latest social media frameworks. We report here on the success of the MSL education program and discuss how this methodological framework can be used to enhance other event based education programs.

  12. GCR Transport in the Brain: Assessment of Self-Shielding, Columnar Damage, and Nuclear Reactions on Cell Inactivation Rates

    NASA Technical Reports Server (NTRS)

    Shavers, M. R.; Atwell, W.; Cucinotta, F. A.; Badhwar, G. D. (Technical Monitor)

    1999-01-01

    Radiation shield design is driven by the need to limit radiation risks while optimizing risk reduction with launch mass/expense penalties. Both limitation and optimization objectives require the development of accurate and complete means for evaluating the effectiveness of various shield materials and body-self shielding. For galactic cosmic rays (GCR), biophysical response models indicate that track structure effects lead to substantially different assessments of shielding effectiveness relative to assessments based on LET-dependent quality factors. Methods for assessing risk to the central nervous system (CNS) from heavy ions are poorly understood at this time. High-energy and charge (HZE) ion can produce tissue events resulting in damage to clusters of cells in a columnar fashion, especially for stopping heavy ions. Grahn (1973) and Todd (1986) have discussed a microlesion concept or model of stochastic tissue events in analyzing damage from HZE's. Some tissues, including the CNS, maybe sensitive to microlesion's or stochastic tissue events in a manner not illuminated by either conventional dosimetry or fluence-based risk factors. HZE ions may also produce important lateral damage to adjacent cells. Fluences of high-energy proton and alpha particles in the GCR are many times higher than HZE ions. Behind spacecraft and body self-shielding the ratio of protons, alpha particles, and neutrons to HZE ions increases several-fold from free-space values. Models of GCR damage behind shielding have placed large concern on the role of target fragments produced from tissue atoms. The self-shielding of the brain reduces the number of heavy ions reaching the interior regions by a large amount and the remaining light particle environment (protons, neutrons, deuterons. and alpha particles) may be the greatest concern. Tracks of high-energy proton produce nuclear reactions in tissue, which can deposit doses of more than 1 Gv within 5 - 10 cell layers. Information on rates of cell killing from GCR, including patterns of cell killing from single particle tracks. can provide useful information on expected differences between proton and HZE tracks and clinical experiences with photon irradiation. To model effects on cells in the brain, it is important that transport models accurately describe changes in the GCR due to interactions in the cranium and proximate tissues. We describe calculations of the attenuated GCR particle fluxes at three dose-points in the brain and associated patterns of cell killing using biophysical models. The effects of the brain self-shielding and bone-tissue interface of the skull in modulating the GCR environment are considered. For each brain dose-point, the mass distribution in the surrounding 4(pi) solid angle is characterized using the CAM model to trace 512 rays. The CAM model describes the self-shielding by converting the tissue distribution to mass-equivalent aluminum, and nominal values of spacecraft shielding is considered. Particle transport is performed with the proton, neutron, and heavy-ion transport code HZETRN with the nuclear fragmentation model QMSFRG. The distribution of cells killed along the path of individual GCR ions is modeled using in vitro cell inactivation data for cells with varying sensitivity. Monte Carlo simulations of arrays of inactivated cells are considered for protons and heavy ions and used to describe the absolute number of cell killing events of various magnitude in the brain from the GCR. Included are simulations of positions of inactivated cells from stopping heavy ions and nuclear stars produced by high-energy ions most importantly, protons and neutrons.

  13. Event-based processing of neutron scattering data

    NASA Astrophysics Data System (ADS)

    Peterson, Peter F.; Campbell, Stuart I.; Reuter, Michael A.; Taylor, Russell J.; Zikovsky, Janik

    2015-12-01

    Many of the world's time-of-flight spallation neutrons sources are migrating to recording individual neutron events. This provides for new opportunities in data processing, the least of which is to filter the events based on correlating them with logs of sample environment and other ancillary equipment. This paper will describe techniques for processing neutron scattering data acquired in event mode which preserve event information all the way to a final spectrum, including any necessary corrections or normalizations. This results in smaller final uncertainties compared to traditional methods, while significantly reducing processing time and memory requirements in typical experiments. Results with traditional histogramming techniques will be shown for comparison.

  14. Event-Based Processing of Neutron Scattering Data

    SciTech Connect

    Peterson, Peter F.; Campbell, Stuart I.; Reuter, Michael A.; Taylor, Russell J.; Zikovsky, Janik L.

    2015-09-16

    Many of the world's time-of-flight spallation neutrons sources are migrating to the recording of individual neutron events. This provides for new opportunities in data processing, the least of which is to filter the events based on correlating them with logs of sample environment and other ancillary equipment. This paper will describe techniques for processing neutron scattering data acquired in event mode that preserve event information all the way to a final spectrum, including any necessary corrections or normalizations. This results in smaller final errors, while significantly reducing processing time and memory requirements in typical experiments. Results with traditional histogramming techniques will be shown for comparison.

  15. MHD compressor---expander conversion system integrated with GCR inside a deployable reflector

    SciTech Connect

    Tuninetti, G. . Research Div.); Botta, E.; Criscuolo, C.; Riscossa, P. . Nuclear Div.); Giammanco, F. . Dipt. di Fisica); Rosa-Clot, M. . Dipt. di Fisica)

    1989-04-20

    This work originates from the proposal MHD Compressor-Expander Conversion System Integrated with a GCR Inside a Deployable Reflector''. The proposal concerned an innovative concept of nuclear, closed-cycle MHD converter for power generation on space-based systems in the multi-megawatt range. The basic element of this converter is the Power Conversion Unit (PCU) consisting of a gas core reactor directly coupled to an MHD expansion channel. Integrated with the PCU, a deployable reflector provides reactivity control. The working fluid could be either uranium hexafluoride or a mixture of uranium hexafluoride and helium, added to enhance the heat transfer properties. The original Statement of Work, which concerned the whole conversion system, was subsequently redirected and focused on the basic mechanisms of neutronics, reactivity control, ionization and electrical conductivity in the PCU. Furthermore, the study was required to be inherently generic such that the study was required to be inherently generic such that the analysis an results can be applied to various nuclear reactor and/or MHD channel designs''.

  16. Assessment and Requirements of Nuclear Reaction Databases for GCR Transport in the Atmosphere and Structures

    NASA Technical Reports Server (NTRS)

    Cucinotta, F. A.; Wilson, J. W.; Shinn, J. L.; Tripathi, R. K.

    1998-01-01

    The transport properties of galactic cosmic rays (GCR) in the atmosphere, material structures, and human body (self-shielding) am of interest in risk assessment for supersonic and subsonic aircraft and for space travel in low-Earth orbit and on interplanetary missions. Nuclear reactions, such as knockout and fragmentation, present large modifications of particle type and energies of the galactic cosmic rays in penetrating materials. We make an assessment of the current nuclear reaction models and improvements in these model for developing required transport code data bases. A new fragmentation data base (QMSFRG) based on microscopic models is compared to the NUCFRG2 model and implications for shield assessment made using the HZETRN radiation transport code. For deep penetration problems, the build-up of light particles, such as nucleons, light clusters and mesons from nuclear reactions in conjunction with the absorption of the heavy ions, leads to the dominance of the charge Z = 0, 1, and 2 hadrons in the exposures at large penetration depths. Light particles are produced through nuclear or cluster knockout and in evaporation events with characteristically distinct spectra which play unique roles in the build-up of secondary radiation's in shielding. We describe models of light particle production in nucleon and heavy ion induced reactions and make an assessment of the importance of light particle multiplicity and spectral parameters in these exposures.

  17. Event-based soil loss models for construction sites

    NASA Astrophysics Data System (ADS)

    Trenouth, William R.; Gharabaghi, Bahram

    2015-05-01

    The elevated rates of soil erosion stemming from land clearing and grading activities during urban development, can result in excessive amounts of eroded sediments entering waterways and causing harm to the biota living therein. However, construction site event-based soil loss simulations - required for reliable design of erosion and sediment controls - are one of the most uncertain types of hydrologic models. This study presents models with improved degree of accuracy to advance the design of erosion and sediment controls for construction sites. The new models are developed using multiple linear regression (MLR) on event-based permutations of the Universal Soil Loss Equation (USLE) and artificial neural networks (ANN). These models were developed using surface runoff monitoring datasets obtained from three sites - Greensborough, Cookstown, and Alcona - in Ontario and datasets mined from the literature for three additional sites - Treynor, Iowa, Coshocton, Ohio and Cordoba, Spain. The predictive MLR and ANN models can serve as both diagnostic and design tools for the effective sizing of erosion and sediment controls on active construction sites, and can be used for dynamic scenario forecasting when considering rapidly changing land use conditions during various phases of construction.

  18. Event-Based Processing of Neutron Scattering Data

    DOE PAGESBeta

    Peterson, Peter F.; Campbell, Stuart I.; Reuter, Michael A.; Taylor, Russell J.; Zikovsky, Janik L.

    2015-09-16

    Many of the world's time-of-flight spallation neutrons sources are migrating to the recording of individual neutron events. This provides for new opportunities in data processing, the least of which is to filter the events based on correlating them with logs of sample environment and other ancillary equipment. This paper will describe techniques for processing neutron scattering data acquired in event mode that preserve event information all the way to a final spectrum, including any necessary corrections or normalizations. This results in smaller final errors, while significantly reducing processing time and memory requirements in typical experiments. Results with traditional histogramming techniquesmore » will be shown for comparison.« less

  19. G-protein Signaling Components GCR1 and GPA1 Mediate Responses to Multiple Abiotic Stresses in Arabidopsis.

    PubMed

    Chakraborty, Navjyoti; Singh, Navneet; Kaur, Kanwaljeet; Raghuram, Nandula

    2015-01-01

    G-protein signaling components have been implicated in some individual stress responses in Arabidopsis, but have not been comprehensively evaluated at the genetic and biochemical level. Stress emerged as the largest functional category in our whole transcriptome analyses of knock-out mutants of GCR1 and/or GPA1 in Arabidopsis (Chakraborty et al., 2015a,b). This led us to ask whether G-protein signaling components offer converging points in the plant's response to multiple abiotic stresses. In order to test this hypothesis, we carried out detailed analysis of the abiotic stress category in the present study, which revealed 144 differentially expressed genes (DEGs), spanning a wide range of abiotic stresses, including heat, cold, salt, light stress etc. Only 10 of these DEGs are shared by all the three mutants, while the single mutants (GCR1/GPA1) shared more DEGs between themselves than with the double mutant (GCR1-GPA1). RT-qPCR validation of 28 of these genes spanning different stresses revealed identical regulation of the DEGs shared between the mutants. We also validated the effects of cold, heat and salt stresses in all the 3 mutants and WT on % germination, root and shoot length, relative water content, proline content, lipid peroxidation and activities of catalase, ascorbate peroxidase and superoxide dismutase. All the 3 mutants showed evidence of stress tolerance, especially to cold, followed by heat and salt, in terms of all the above parameters. This clearly shows the role of GCR1 and GPA1 in mediating the plant's response to multiple abiotic stresses for the first time, especially cold, heat and salt stresses. This also implies a role for classical G-protein signaling pathways in stress sensitivity in the normal plants of Arabidopsis. This is also the first genetic and biochemical evidence of abiotic stress tolerance rendered by knock-out mutation of GCR1 and/or GPA1. This suggests that G-protein signaling pathway could offer novel common targets for the development of tolerance/resistance to multiple abiotic stresses. PMID:26635828

  20. G-protein Signaling Components GCR1 and GPA1 Mediate Responses to Multiple Abiotic Stresses in Arabidopsis

    PubMed Central

    Chakraborty, Navjyoti; Singh, Navneet; Kaur, Kanwaljeet; Raghuram, Nandula

    2015-01-01

    G-protein signaling components have been implicated in some individual stress responses in Arabidopsis, but have not been comprehensively evaluated at the genetic and biochemical level. Stress emerged as the largest functional category in our whole transcriptome analyses of knock-out mutants of GCR1 and/or GPA1 in Arabidopsis (Chakraborty et al., 2015a,b). This led us to ask whether G-protein signaling components offer converging points in the plant's response to multiple abiotic stresses. In order to test this hypothesis, we carried out detailed analysis of the abiotic stress category in the present study, which revealed 144 differentially expressed genes (DEGs), spanning a wide range of abiotic stresses, including heat, cold, salt, light stress etc. Only 10 of these DEGs are shared by all the three mutants, while the single mutants (GCR1/GPA1) shared more DEGs between themselves than with the double mutant (GCR1-GPA1). RT-qPCR validation of 28 of these genes spanning different stresses revealed identical regulation of the DEGs shared between the mutants. We also validated the effects of cold, heat and salt stresses in all the 3 mutants and WT on % germination, root and shoot length, relative water content, proline content, lipid peroxidation and activities of catalase, ascorbate peroxidase and superoxide dismutase. All the 3 mutants showed evidence of stress tolerance, especially to cold, followed by heat and salt, in terms of all the above parameters. This clearly shows the role of GCR1 and GPA1 in mediating the plant's response to multiple abiotic stresses for the first time, especially cold, heat and salt stresses. This also implies a role for classical G-protein signaling pathways in stress sensitivity in the normal plants of Arabidopsis. This is also the first genetic and biochemical evidence of abiotic stress tolerance rendered by knock-out mutation of GCR1 and/or GPA1. This suggests that G-protein signaling pathway could offer novel common targets for the development of tolerance/resistance to multiple abiotic stresses. PMID:26635828

  1. Determining the Magnitude of Neutron and Galactic Cosmic Ray (GCR) Fluxes at the Moon using the Lunar Exploration Neutron Detector during the Historic Space-Age Era of High GCR Flux

    NASA Astrophysics Data System (ADS)

    Chin, G.; Sagdeev, R.; Boynton, W. V.; Mitrofanov, I. G.; Milikh, G. M.; Su, J. J.; Livengood, T. A.; McClanahan, T. P.; Evans, L.; Starr, R. D.; litvak, M. L.; Sanin, A.

    2013-12-01

    The Lunar Reconnaissance Orbiter (LRO) was launched June 18, 2009 during an historic space-age era of minimum solar activity [1]. The lack of solar sunspot activity signaled a complex set of heliospheric phenomena [2,3,4] that also gave rise to a period of unprecedentedly high Galactic Cosmic Ray (GCR) flux [5]. These events coincided with the primary mission of the Lunar Exploration Neutron Detector (LEND, [6]), onboard LRO in a nominal 50-km circular orbit of the Moon [7]. Methods to calculate the emergent neutron albedo population using Monte Carlo techniques [8] rely on an estimate of the GCR flux and spectra calibrated at differing periods of solar activity [9,10,11]. Estimating the actual GCR flux at the Moon during the LEND's initial period of operation requires a correction using a model-dependent heliospheric transport modulation parameter [12] to adjust the GCR flux appropriate to this unique solar cycle. These corrections have inherent uncertainties depending on model details [13]. Precisely determining the absolute neutron and GCR fluxes is especially important in understanding the emergent lunar neutrons measured by LEND and subsequently in estimating the hydrogen/water content in the lunar regolith [6]. LEND is constructed with a set of neutron detectors to meet differing purposes [6]. Specifically there are two sets of detector systems that measure the flux of epithermal neutrons: a) the uncollimated Sensor for Epi-Thermal Neutrons (SETN) and b) the Collimated Sensor for Epi-Thermal Neutrons (CSETN). LEND SETN and CSETN observations form a complementary set of simultaneous measurements that determine the absolute scale of emergent lunar neutron flux in an unambiguous fashion and without the need for correcting to differing solar-cycle conditions. LEND measurements are combined with a detailed understanding of the sources of instrumental back-ground, and the performance of CSETN and SETN. This comparison allows us to calculate a constant scale factor that determines the absolute flux of neutrons at the Moon and then subsequently to deduce the proper scale of the GCR flux. References: [1] H. S. Ahluwakia and R. C. Ygbuhay (2010) Twelfth International Solar Wind Conference, 699-702. [2] F. B. McDonald et al. (2010) JRL, 37, L18101. [3] H. Moraal and P. H. Stoker (2010) JGR, 115, 12109-12118. [4] R. Kataoka et al. (2012) Space Weather, 10, 11001-11007. [4] C-L. Huang et al. (2009), JRL, 37, L09109-L09104. [5] R. A. Mewaldt et al. (2010) Ap. J Lett., 723, L1-L6. [6] I. G. Mitrofanov et al. (2010) Space Science Rev., 150, 283-207. [7] C. R. Tooley et al. (2010) Space Science Rev., 150, 23-62. [8] G. W. McKinney et al. (2006) JGR, 111, 6004-6018. [9] P. M. O'Neil (2010) IEEE Trans. Nucl. Sci., 57(6), 3148-3153. [10] American National Standards Institute Tech. Rep. ISO 15390 (2004). [11] I. G. Usokin et al. (2008) JGR, 110, A12108. [12] M. D. Looper et al. (2013) Space Weather, 11, 142-152. [13] A. I. Mrigakshi et al. (2012) JGR, 117, A08109-A08121.

  2. Neuromorphic Event-Based 3D Pose Estimation

    PubMed Central

    Reverter Valeiras, David; Orchard, Garrick; Ieng, Sio-Hoi; Benosman, Ryad B.

    2016-01-01

    Pose estimation is a fundamental step in many artificial vision tasks. It consists of estimating the 3D pose of an object with respect to a camera from the object's 2D projection. Current state of the art implementations operate on images. These implementations are computationally expensive, especially for real-time applications. Scenes with fast dynamics exceeding 30–60 Hz can rarely be processed in real-time using conventional hardware. This paper presents a new method for event-based 3D object pose estimation, making full use of the high temporal resolution (1 μs) of asynchronous visual events output from a single neuromorphic camera. Given an initial estimate of the pose, each incoming event is used to update the pose by combining both 3D and 2D criteria. We show that the asynchronous high temporal resolution of the neuromorphic camera allows us to solve the problem in an incremental manner, achieving real-time performance at an update rate of several hundreds kHz on a conventional laptop. We show that the high temporal resolution of neuromorphic cameras is a key feature for performing accurate pose estimation. Experiments are provided showing the performance of the algorithm on real data, including fast moving objects, occlusions, and cases where the neuromorphic camera and the object are both in motion. PMID:26834547

  3. A storm event-based approach to TMDL development.

    PubMed

    Hsu, Tsung-Hung; Lin, Jen-Yang; Lee, Tsu-Chuan; Zhang, Harry X; Yu, Shaw L

    2010-04-01

    It is vitally important to define the critical condition for a receiving water body in the total maximum daily load (TMDL) development process. One of the major disadvantages of using a continuous simulation approach is that there is no guarantee that the most critical condition will be covered within the subjectively selected representative hydrologic period, which is usually several years depending on the availability of data. Another limitation of the continuous simulation approach, compared to a design storm approach, is the lack of an estimate of the risk involved. Because of the above limitations, a storm event-based critical flow-storm (CFS) approach was previously developed to explicitly address the critical condition as a combination of a prescribed stream flow and a storm event of certain magnitude, both having a certain frequency of occurrence and when combined, would create a critical condition. The CFS approach was tested successfully in a TMDL study for Muddy Creek in Virginia. The present paper reports results of a comparative study on the applicability of the CFS approach in Taiwan. The Dy-yu creek watershed in northern Taiwan differs significantly from Muddy Creek in terms of climate, hydrology, terrain, and other characteristics. Results show that the critical condition for different watersheds might be also different, and that the CFS approach could clearly define that critical condition and should be considered as an alternative method for TMDL development to a continuous simulation approach. PMID:19266300

  4. Event-Based User Classification in Weibo Media

    PubMed Central

    Wang, Wendong; Cheng, Shiduan; Que, Xirong

    2014-01-01

    Weibo media, known as the real-time microblogging services, has attracted massive attention and support from social network users. Weibo platform offers an opportunity for people to access information and changes the way people acquire and disseminate information significantly. Meanwhile, it enables people to respond to the social events in a more convenient way. Much of the information in Weibo media is related to some events. Users who post different contents, and exert different behavior or attitude may lead to different contribution to the specific event. Therefore, classifying the large amount of uncategorized social circles generated in Weibo media automatically from the perspective of events has been a promising task. Under this circumstance, in order to effectively organize and manage the huge amounts of users, thereby further managing their contents, we address the task of user classification in a more granular, event-based approach in this paper. By analyzing real data collected from Sina Weibo, we investigate the Weibo properties and utilize both content information and social network information to classify the numerous users into four primary groups: celebrities, organizations/media accounts, grassroots stars, and ordinary individuals. The experiments results show that our method identifies the user categories accurately. PMID:25133235

  5. Self-Driven Decay Heat Removal in a GCR Closed Brayton Cycle Power System

    SciTech Connect

    Wright, Steven A.; Lipinski, Ronald J.

    2006-07-01

    Closed Brayton Cycle (CBC) systems that are driven by Gas Cooled Reactors (GCR) are being evaluated for high-efficiency electricity generation. These systems were also selected by the Naval Reactor Prime Contractor team for use as space power systems. This paper describes the decay heat removal performance of these systems. A key question for such space or terrestrial based CBC systems is how to shut down the reactor while still removing the decay heat without using substantial amounts of auxiliary power. Tests in the Sandia Brayton Loop (SBL) show that the Brayton cycle is capable of operating on sensible heat for very long times ({approx} hour) after the reactor is shut down. This paper describes the measured and predicted results of generated electrical power produced as a function of time after the heat source had been turned off in the Sandia Brayton Loop. The measured results were obtained from an electrically heated closed Brayton cycle test loop (SBL) that Sandia fabricated and has operating within the laboratories. The predicted behavior is based on integrated dynamic system models that are capable of predicting both the transient and steady state behavior of nuclear heated or electrically heated Brayton cycle systems. The measured data was obtained by running the SBL and shutting off the electrical heater while adjusting the flow through the loop to keep the system operating at (or just above) its self-sustaining operating power level. During the test we were able to produce {approx}500 W of power for over 73 minutes after the heater power was turned off. Thus the Brayton loop was able to operate at self-sustaining conditions (or better) for over one hour. During this time the turbo-compressor was transporting the sensible heat in the heater, ducting, and recuperator to the waste heat rejection system for over an hour. For a reactor-driven system in space, this would give the shutdown decay power sufficient time to decay to levels where it could be removed radially through the core by conduction and then radiated to space. The model predictions show similar behavior; however, the actual generated electrical power was greater than predicted. (authors)

  6. Event-based internet biosurveillance: relation to epidemiological observation

    PubMed Central

    2012-01-01

    Background The World Health Organization (WHO) collects and publishes surveillance data and statistics for select diseases, but traditional methods of gathering such data are time and labor intensive. Event-based biosurveillance, which utilizes a variety of Internet sources, complements traditional surveillance. In this study we assess the reliability of Internet biosurveillance and evaluate disease-specific alert criteria against epidemiological data. Methods We reviewed and compared WHO epidemiological data and Argus biosurveillance system data for pandemic (H1N1) 2009 (April 2009 – January 2010) from 8 regions and 122 countries to: identify reliable alert criteria among 15 Argus-defined categories; determine the degree of data correlation for disease progression; and assess timeliness of Internet information. Results Argus generated a total of 1,580 unique alerts; 5 alert categories generated statistically significant (p < 0.05) correlations with WHO case count data; the sum of these 5 categories was highly correlated with WHO case data (r = 0.81, p < 0.0001), with expected differences observed among the 8 regions. Argus reported first confirmed cases on the same day as WHO for 21 of the first 64 countries reporting cases, and 1 to 16 days (average 1.5 days) ahead of WHO for 42 of those countries. Conclusion Confirmed pandemic (H1N1) 2009 cases collected by Argus and WHO methods returned consistent results and confirmed the reliability and timeliness of Internet information. Disease-specific alert criteria provide situational awareness and may serve as proxy indicators to event progression and escalation in lieu of traditional surveillance data; alerts may identify early-warning indicators to another pandemic, preparing the public health community for disease events. PMID:22709988

  7. The bacterial cell cycle regulator GcrA is a σ70 cofactor that drives gene expression from a subset of methylated promoters.

    PubMed

    Haakonsen, Diane L; Yuan, Andy H; Laub, Michael T

    2015-11-01

    Cell cycle progression in most organisms requires tightly regulated programs of gene expression. The transcription factors involved typically stimulate gene expression by binding specific DNA sequences in promoters and recruiting RNA polymerase. Here, we found that the essential cell cycle regulator GcrA in Caulobacter crescentus activates the transcription of target genes in a fundamentally different manner. GcrA forms a stable complex with RNA polymerase and localizes to almost all active σ(70)-dependent promoters in vivo but activates transcription primarily at promoters harboring certain DNA methylation sites. Whereas most transcription factors that contact σ(70) interact with domain 4, GcrA interfaces with domain 2, the region that binds the -10 element during strand separation. Using kinetic analyses and a reconstituted in vitro transcription assay, we demonstrated that GcrA can stabilize RNA polymerase binding and directly stimulate open complex formation to activate transcription. Guided by these studies, we identified a regulon of ∼ 200 genes, providing new insight into the essential functions of GcrA. Collectively, our work reveals a new mechanism for transcriptional regulation, and we discuss the potential benefits of activating transcription by promoting RNA polymerase isomerization rather than recruitment exclusively. PMID:26545812

  8. Event based climatology of extreme precipitation in Europe

    NASA Astrophysics Data System (ADS)

    Nissen, Katrin M.; Becker, Nico; Ulbrich, Uwe

    2015-04-01

    An event based detection algorithm to identify extreme precipitation events in gridded data sets is introduced and applied to the observational E-OBS data set. The algorithm identifies all grid boxes in which the rainfall exceeds a threshold, which depends on the location and the aggregation period. The aggregation periods taken into account in this study range from a single time step up to 72 hours. The local 50-year return level is calculated for all aggregation periods and used as a threshold. All identified grid boxes which are located within the same continuous rain area (i.e. which are not separated by rain free grid boxes) are considered as belonging to the same event and form a cluster. The centre of mass is calculated for each cluster. The clusters are then tracked in time using a nearest neighbor approach. Thus, each detected event can consist of several grid boxes and can last for several time steps. A precipitation severity index (PSI) is assigned to the events. The severity index takes the affected area and the amount of precipitation accumulated over the duration of the event into account. It is normalized by the long-term mean annual precipitation sum expected for the grid box. The severity index can be used to compare the strength of the identified events. The detection algorithm also stores additional information for each event, such as the date, location, affected area, duration, severity and maximum precipitation. Comparing all events detected in the E-OBS data set, which exceeded the local 50-year return levels, the highest severity index was calculated for an event affecting Spain, which took place in November 1997. It had a severity index of 49.9 and was also described in the literature. In comparison, the average PSI for the extreme precipitation events over Europe is 2.4. Overall, the most active season for extreme precipitation in Europe is summer. The longest duration of an event in the data set was 11 days. It occurred over Estonia in August 1987. The largest extend (152300km2) is associated with an event which occurred in September 1992 with its centre over Eastern Europe. This work has been conducted within the EU project RAIN (Risk Analysis of Infrastructure Networks in response to extreme weather).

  9. Draft Title 40 CFR 191 compliance certification application for the Waste Isolation Pilot Plant. Volume 6: Appendix GCR Volume 1

    SciTech Connect

    1995-03-31

    The Geological Characterization Report (GCR) for the WIPP site presents, in one document, a compilation of geologic information available to August, 1978, which is judged to be relevant to studies for the WIPP. The Geological Characterization Report for the WIPP site is neither a preliminary safety analysis report nor an environmental impact statement; these documents, when prepared, should be consulted for appropriate discussion of safety analysis and environmental impact. The Geological Characterization Report of the WIPP site is a unique document and at this time is not required by regulatory process. An overview is presented of the purpose of the WIPP, the purpose of the Geological Characterization Report, the site selection criteria, the events leading to studies in New Mexico, status of studies, and the techniques employed during geological characterization.

  10. Outbreak!: An Event-Based Science Module. Teacher's Guide. Disease and Immunity Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school life science or physical science teachers to help their students learn scientific literacy through event-based science. Unlike traditional curricula, the event- based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork,

  11. Gold Rush!: An Event-Based Science Module. Student Edition. Rocks and Minerals Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and

  12. Blackout!: An Event-Based Science Module. Teacher's Guide. Electricity and Solar Activity Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school earth science or physical science teachers to help their students learn scientific literacy through event-based science. Unlike traditional curricula, the event- based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork,

  13. Thrill Ride! An Event-Based Science Module. Teacher's Guide. Force and Motion Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school life science or physical science teachers to help their students learn scientific literacy through event-based science. Unlike traditional curricula, the event- based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork,

  14. Tornado! An Event-Based Science Module. Student Edition. Meteorology Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and

  15. Gold Medal!: An Event-Based Science Module. Teacher's Guide. Physiology Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school life science or physical science teachers to help their students learn scientific literacy through event-based science. Unlike traditional curricula, the event- based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork,

  16. Survive?: An Event-Based Science Module. Student Edition. Animals and Adaptation Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and

  17. Earthquake!: An Event-Based Science Module. Teacher's Guide. Earth Science Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school earth science teachers to help their students learn about earthquakes and scientific literacy through event-based science. Unlike traditional curricula, the event- based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork,

  18. Gold Rush!: An Event-Based Science Module. Teacher's Guide. Geology Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school earth science or general science teachers to help their students learn scientific literacy through event-based science. Unlike traditional curricula, the event- based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork,

  19. First Flight!: An Event-Based Science Module. Student Edition. Physics Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and

  20. Volcano!: An Event-Based Science Module. Student Edition. Geology Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and

  1. Survive? An Event-Based Science Module. Teacher's Guide. Animals and Adaptation Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school earth science teachers to help their students learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research,

  2. Outbreak!: An Event-Based Science Module. Student Edition. Disease and Immunity Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and

  3. Thrill Ride! An Event-Based Science Module. Student Edition. Force and Motion Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and

  4. Asteroid! An Event-Based Science Module. Student Edition. Astronomy Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and

  5. Tornado! An Event-Based Science Module. Teacher's Guide. Meteorology Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school earth science teachers to help their students learn about problems with tornadoes and scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning,

  6. Asteroid! An Event-Based Science Module. Teacher's Guide. Astronomy Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school earth science or general science teachers to help their students learn scientific literacy through event-based science. Unlike traditional curricula, the event- based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork,

  7. Gold Medal! An Event-Based Science Module. Student Edition. Physiology Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and

  8. Volcano!: An Event-Based Science Module. Teacher's Guide. Geology Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school earth science teachers to help their students learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research,

  9. Fraud! An Event-Based Science Module. Teacher's Guide. Chemistry Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school life science or physical science teachers to help their students learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork,

  10. First Flight!: An Event-Based Science Module Teacher's Guide. Physics Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school life science or physical science teachers to help their students learn scientific literacy through event-based science. Unlike traditional curricula, the event- based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork,

  11. Fraud! An Event-Based Science Module. Student Edition. Chemistry Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and

  12. Blight! An Event-Based Science Module. Student Edition. Plants and Plant Diseases Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and

  13. Blackout!: An Event-Based Science Module. Student Edition. Electricity and Solar Activity Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and

  14. Flood!: An Event-Based Science Module. Teacher's Guide. Stream Dynamics Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school earth science teachers to help their students learn about problems with floods and scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning,

  15. Blight! An Event-Based Science Module. Teacher's Guide. Plants and Plant Diseases Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school life science or physical science teachers to help their students learn scientific literacy through event-based science. Unlike traditional curricula, the event- based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork,

  16. Gold Medal! An Event-Based Science Module. Student Edition. Physiology Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and…

  17. Gold Medal!: An Event-Based Science Module. Teacher's Guide. Physiology Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school life science or physical science teachers to help their students learn scientific literacy through event-based science. Unlike traditional curricula, the event- based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork,…

  18. Toxic Leak!: An Event-Based Science Module. Student Edition. Groundwater Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for the middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and…

  19. First Flight!: An Event-Based Science Module Teacher's Guide. Physics Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school life science or physical science teachers to help their students learn scientific literacy through event-based science. Unlike traditional curricula, the event- based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork,…

  20. First Flight!: An Event-Based Science Module. Student Edition. Physics Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and…

  1. Blight! An Event-Based Science Module. Teacher's Guide. Plants and Plant Diseases Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school life science or physical science teachers to help their students learn scientific literacy through event-based science. Unlike traditional curricula, the event- based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork,…

  2. Blight! An Event-Based Science Module. Student Edition. Plants and Plant Diseases Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and…

  3. Earthquake!: An Event-Based Science Module. Teacher's Guide. Earth Science Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school earth science teachers to help their students learn about earthquakes and scientific literacy through event-based science. Unlike traditional curricula, the event- based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork,…

  4. Earthquake!: An Event-Based Science Module. Student Edition. Earth Science Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and…

  5. Asteroid! An Event-Based Science Module. Teacher's Guide. Astronomy Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school earth science or general science teachers to help their students learn scientific literacy through event-based science. Unlike traditional curricula, the event- based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork,…

  6. Asteroid! An Event-Based Science Module. Student Edition. Astronomy Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and…

  7. Fire!: An Event-Based Science Module. Teacher's Guide. Chemistry and Fire Ecology Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school earth science or physical science teachers to help their students learn scientific literacy through event-based science. Unlike traditional curricula, the event- based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork,

  8. Fire!: An Event-Based Science Module. Student Edition. Chemistry and Fire Ecology Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and

  9. Fire!: An Event-Based Science Module. Student Edition. Chemistry and Fire Ecology Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and…

  10. Fire!: An Event-Based Science Module. Teacher's Guide. Chemistry and Fire Ecology Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school earth science or physical science teachers to help their students learn scientific literacy through event-based science. Unlike traditional curricula, the event- based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork,…

  11. Tornado! An Event-Based Science Module. Student Edition. Meteorology Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and…

  12. Tornado! An Event-Based Science Module. Teacher's Guide. Meteorology Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school earth science teachers to help their students learn about problems with tornadoes and scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning,…

  13. Gold Rush!: An Event-Based Science Module. Student Edition. Rocks and Minerals Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and…

  14. Gold Rush!: An Event-Based Science Module. Teacher's Guide. Geology Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school earth science or general science teachers to help their students learn scientific literacy through event-based science. Unlike traditional curricula, the event- based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork,…

  15. Oil Spill!: An Event-Based Science Module. Teacher's Guide. Oceanography Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school earth science or general science teachers to help their students learn scientific literacy through event-based science. Unlike traditional curricula, the event- based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork,…

  16. Oil Spill! An Event-Based Science Module. Student Edition. Oceanography Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and…

  17. Survive? An Event-Based Science Module. Teacher's Guide. Animals and Adaptation Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school earth science teachers to help their students learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research,…

  18. Survive?: An Event-Based Science Module. Student Edition. Animals and Adaptation Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and…

  19. Volcano!: An Event-Based Science Module. Teacher's Guide. Geology Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school earth science teachers to help their students learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research,…

  20. Volcano!: An Event-Based Science Module. Student Edition. Geology Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school students to learn scientific literacy through event-based science. Unlike traditional curricula, the event-based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork, independent research, hands-on investigations, and…

  1. Spatial gradients of GCR protons in the inner heliosphere derived from Ulysses COSPIN/KET and PAMELA measurements

    NASA Astrophysics Data System (ADS)

    Gieseler, J.; Heber, B.

    2016-04-01

    Context. During the transition from solar cycle 23 to 24 from 2006 to 2009, the Sun was in an unusual solar minimum with very low activity over a long period. These exceptional conditions included a very low interplanetary magnetic field (IMF) strength and a high tilt angle, which both play an important role in the modulation of galactic cosmic rays (GCR) in the heliosphere. Thus, the radial and latitudinal gradients of GCRs are very much expected to depend not only on the solar magnetic epoch, but also on the overall modulation level. Aims: We determine the non-local radial and the latitudinal gradients of protons in the rigidity range from ~0.45 to 2 GV. Methods: This was accomplished by using data from the satellite-borne experiment Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) at Earth and the Kiel Electron Telescope (KET) onboard Ulysses on its highly inclined Keplerian orbit around the Sun with the aphelion at Jupiter's orbit. Results: In comparison to the previous A> 0 solar magnetic epoch, we find that the absolute value of the latitudinal gradient is lower at higher and higher at lower rigidities. This energy dependence is therefore a crucial test for models that describe the cosmic ray transport in the inner heliosphere.

  2. KlGcr1 controls glucose-6-phosphate dehydrogenase activity and responses to H2O2, cadmium and arsenate in Kluyveromyces lactis.

    PubMed

    Lamas-Maceiras, Mónica; Rodríguez-Belmonte, Esther; Becerra, Manuel; González-Siso, Ma Isabel; Cerdán, Ma Esperanza

    2015-09-01

    It has been previously reported that Gcr1 differentially controls growth and sugar utilization in Saccharomyces cerevisiae and Kluyveromyces lactis, although the regulatory mechanisms causing activation of glycolytic genes are conserved (Neil et al., 2004). We have found that KlGCR1 deletion diminishes glucose consumption and ethanol production, but increases resistance to oxidative stress caused by H2O2, cadmium and arsenate, glucose 6P dehydrogenase activity, and the NADPH/NADP(+) and GSH/GSSG ratios in K. lactis. The gene KlZWF1 that encodes for glucose 6P dehydrogenase, the first enzyme in the pentose phosphate pathway, is transcriptionally regulated by KlGcr1. The high resistance to oxidative stress observed in the ΔKlgcr1 mutant strain, could be explained as a consequence of an increased flux of glucose through the pentose phosphate pathway. Since mitochondrial respiration decreases in the ΔKlgcr1 mutant (García-Leiro et al., 2010), the reoxidation of the NADPH, produced through the pentose phosphate pathway, has to be achieved by the reduction of other molecules implied in the defense against oxidative stress, like GSSG. The higher GSH/GSSG ratio in the mutant would explain its phenotype of increased resistance to oxidative stress. PMID:26164373

  3. G-protein α-subunit (GPA1) regulates stress, nitrate and phosphate response, flavonoid biosynthesis, fruit/seed development and substantially shares GCR1 regulation in A. thaliana.

    PubMed

    Chakraborty, Navjyoti; Sharma, Priyanka; Kanyuka, Kostya; Pathak, Ravi Ramesh; Choudhury, Devapriya; Hooley, Richard; Raghuram, Nandula

    2015-12-01

    Heterotrimeric G-proteins are implicated in several plant processes, but the mechanisms of signal-response coupling and the roles of G-protein coupled receptors in general and GCR1 in particular, remain poorly understood. We isolated a knock-out mutant of the Arabidopsis G-protein α subunit (gpa1-5) and analysed its transcriptome to understand the genomewide role of GPA1 and compared it with that of our similar analysis of a GCR1 mutant (Chakraborty et al. 2015, PLoS ONE 10(2):e0117819). We found 394 GPA1-regulated genes spanning 79 biological processes, including biotic and abiotic stresses, development, flavonoid biosynthesis, transcription factors, transporters and nitrate/phosphate responses. Many of them are either unknown or unclaimed explicitly in other published gpa1 mutant transcriptome analyses. A comparison of all known GPA1-regulated genes (including the above 394) with 350 GCR1-regulated genes revealed 114 common genes. This can be best explained by GCR1-GPA1 coupling, or by convergence of their independent signaling pathways. Though the common genes in our GPA1 and GCR1 mutant datasets constitute only 26% of the GPA1-regulated and 30% of the GCR1-responsive genes, they belong to nearly half of all the processes affected in both the mutants. Thus, GCR1 and GPA1 regulate not only some common genes, but also different genes belonging to the same processes to achieve similar outcomes. Overall, we validate some known and report many hitherto unknown roles of GPA1 in plants, including agronomically important ones such as biotic stress and nutrient response, and also provide compelling genetic evidence to revisit the role of GCR1 in G-protein signalling. PMID:26346778

  4. Efficiency of event-based sampling according to error energy criterion.

    PubMed

    Miskowicz, Marek

    2010-01-01

    The paper belongs to the studies that deal with the effectiveness of the particular event-based sampling scheme compared to the conventional periodic sampling as a reference. In the present study, the event-based sampling according to a constant energy of sampling error is analyzed. This criterion is suitable for applications where the energy of sampling error should be bounded (i.e., in building automation, or in greenhouse climate monitoring and control). Compared to the integral sampling criteria, the error energy criterion gives more weight to extreme sampling error values. The proposed sampling principle extends a range of event-based sampling schemes and makes the choice of particular sampling criterion more flexible to application requirements. In the paper, it is proved analytically that the proposed event-based sampling criterion is more effective than the periodic sampling by a factor defined by the ratio of the maximum to the mean of the cubic root of the signal time-derivative square in the analyzed time interval. Furthermore, it is shown that the sampling according to energy criterion is less effective than the send-on-delta scheme but more effective than the sampling according to integral criterion. On the other hand, it is indicated that higher effectiveness in sampling according to the selected event-based criterion is obtained at the cost of increasing the total sampling error defined as the sum of errors for all the samples taken. PMID:22294925

  5. Efficiency of Event-Based Sampling According to Error Energy Criterion

    PubMed Central

    Miskowicz, Marek

    2010-01-01

    The paper belongs to the studies that deal with the effectiveness of the particular event-based sampling scheme compared to the conventional periodic sampling as a reference. In the present study, the event-based sampling according to a constant energy of sampling error is analyzed. This criterion is suitable for applications where the energy of sampling error should be bounded (i.e., in building automation, or in greenhouse climate monitoring and control). Compared to the integral sampling criteria, the error energy criterion gives more weight to extreme sampling error values. The proposed sampling principle extends a range of event-based sampling schemes and makes the choice of particular sampling criterion more flexible to application requirements. In the paper, it is proved analytically that the proposed event-based sampling criterion is more effective than the periodic sampling by a factor defined by the ratio of the maximum to the mean of the cubic root of the signal time-derivative square in the analyzed time interval. Furthermore, it is shown that the sampling according to energy criterion is less effective than the send-on-delta scheme but more effective than the sampling according to integral criterion. On the other hand, it is indicated that higher effectiveness in sampling according to the selected event-based criterion is obtained at the cost of increasing the total sampling error defined as the sum of errors for all the samples taken. PMID:22294925

  6. An Event-Based Approach to Distributed Diagnosis of Continuous Systems

    NASA Technical Reports Server (NTRS)

    Daigle, Matthew; Roychoudhurry, Indranil; Biswas, Gautam; Koutsoukos, Xenofon

    2010-01-01

    Distributed fault diagnosis solutions are becoming necessary due to the complexity of modern engineering systems, and the advent of smart sensors and computing elements. This paper presents a novel event-based approach for distributed diagnosis of abrupt parametric faults in continuous systems, based on a qualitative abstraction of measurement deviations from the nominal behavior. We systematically derive dynamic fault signatures expressed as event-based fault models. We develop a distributed diagnoser design algorithm that uses these models for designing local event-based diagnosers based on global diagnosability analysis. The local diagnosers each generate globally correct diagnosis results locally, without a centralized coordinator, and by communicating a minimal number of measurements between themselves. The proposed approach is applied to a multi-tank system, and results demonstrate a marked improvement in scalability compared to a centralized approach.

  7. Event-Based Control Strategy for Mobile Robots in Wireless Environments

    PubMed Central

    Socas, Rafael; Dormido, Sebastián; Dormido, Raquel; Fabregas, Ernesto

    2015-01-01

    In this paper, a new event-based control strategy for mobile robots is presented. It has been designed to work in wireless environments where a centralized controller has to interchange information with the robots over an RF (radio frequency) interface. The event-based architectures have been developed for differential wheeled robots, although they can be applied to other kinds of robots in a simple way. The solution has been checked over classical navigation algorithms, like wall following and obstacle avoidance, using scenarios with a unique or multiple robots. A comparison between the proposed architectures and the classical discrete-time strategy is also carried out. The experimental results shows that the proposed solution has a higher efficiency in communication resource usage than the classical discrete-time strategy with the same accuracy. PMID:26633412

  8. Event-Based Control Strategy for Mobile Robots in Wireless Environments.

    PubMed

    Socas, Rafael; Dormido, Sebastián; Dormido, Raquel; Fabregas, Ernesto

    2015-01-01

    In this paper, a new event-based control strategy for mobile robots is presented. It has been designed to work in wireless environments where a centralized controller has to interchange information with the robots over an RF (radio frequency) interface. The event-based architectures have been developed for differential wheeled robots, although they can be applied to other kinds of robots in a simple way. The solution has been checked over classical navigation algorithms, like wall following and obstacle avoidance, using scenarios with a unique or multiple robots. A comparison between the proposed architectures and the classical discrete-time strategy is also carried out. The experimental results shows that the proposed solution has a higher efficiency in communication resource usage than the classical discrete-time strategy with the same accuracy. PMID:26633412

  9. Event Based Simulator for Parallel Computing over the Wide Area Network for Real Time Visualization

    NASA Astrophysics Data System (ADS)

    Sundararajan, Elankovan; Harwood, Aaron; Kotagiri, Ramamohanarao; Satria Prabuwono, Anton

    As the computational requirement of applications in computational science continues to grow tremendously, the use of computational resources distributed across the Wide Area Network (WAN) becomes advantageous. However, not all applications can be executed over the WAN due to communication overhead that can drastically slowdown the computation. In this paper, we introduce an event based simulator to investigate the performance of parallel algorithms executed over the WAN. The event based simulator known as SIMPAR (SIMulator for PARallel computation), simulates the actual computations and communications involved in parallel computation over the WAN using time stamps. Visualization of real time applications require steady stream of processed data flow for visualization purposes. Hence, SIMPAR may prove to be a valuable tool to investigate types of applications and computing resource requirements to provide uninterrupted flow of processed data for real time visualization purposes. The results obtained from the simulation show concurrence with the expected performance using the L-BSP model.

  10. Asymptotic Effectiveness of the Event-Based Sampling according to the Integral Criterion

    PubMed Central

    Miskowicz, Marek

    2007-01-01

    A rapid progress in intelligent sensing technology creates new interest in a development of analysis and design of non-conventional sampling schemes. The investigation of the event-based sampling according to the integral criterion is presented in this paper. The investigated sampling scheme is an extension of the pure linear send-on-delta/level-crossing algorithm utilized for reporting the state of objects monitored by intelligent sensors. The motivation of using the event-based integral sampling is outlined. The related works in adaptive sampling are summarized. The analytical closed-form formulas for the evaluation of the mean rate of event-based traffic, and the asymptotic integral sampling effectiveness, are derived. The simulation results verifying the analytical formulas are reported. The effectiveness of the integral sampling is compared with the related linear send-on-delta/level-crossing scheme. The calculation of the asymptotic effectiveness for common signals, which model the state evolution of dynamic systems in time, is exemplified.

  11. Music, clicks, and their imaginations favor differently the event-based timing component for rhythmic movements.

    PubMed

    Bravi, Riccardo; Quarta, Eros; Del Tongo, Claudia; Carbonaro, Nicola; Tognetti, Alessandro; Minciacchi, Diego

    2015-06-01

    The involvement or noninvolvement of a clock-like neural process, an effector-independent representation of the time intervals to produce, is described as the essential difference between event-based and emergent timing. In a previous work (Bravi et al. in Exp Brain Res 232:1663-1675, 2014a. doi: 10.1007/s00221-014-3845-9 ), we studied repetitive isochronous wrist's flexion-extensions (IWFEs), performed while minimizing visual and tactile information, to clarify whether non-temporal and temporal characteristics of paced auditory stimuli affect the precision and accuracy of the rhythmic motor performance. Here, with the inclusion of new recordings, we expand the examination of the dataset described in our previous study to investigate whether simple and complex paced auditory stimuli (clicks and music) and their imaginations influence in a different way the timing mechanisms for repetitive IWFEs. Sets of IWFEs were analyzed by the windowed (lag one) autocorrelation-wγ(1), a statistical method recently introduced for the distinction between event-based and emergent timing. Our findings provide evidence that paced auditory information and its imagination favor the engagement of a clock-like neural process, and specifically that music, unlike clicks, lacks the power to elicit event-based timing, not counteracting the natural shift of wγ(1) toward positive values as frequency of movements increase. PMID:25837726

  12. An Event-Based Solution to the Perspective-n-Point Problem

    PubMed Central

    Reverter Valeiras, David; Kime, Sihem; Ieng, Sio-Hoi; Benosman, Ryad Benjamin

    2016-01-01

    The goal of the Perspective-n-Point problem (PnP) is to find the relative pose between an object and a camera from a set of n pairings between 3D points and their corresponding 2D projections on the focal plane. Current state of the art solutions, designed to operate on images, rely on computationally expensive minimization techniques. For the first time, this work introduces an event-based PnP algorithm designed to work on the output of a neuromorphic event-based vision sensor. The problem is formulated here as a least-squares minimization problem, where the error function is updated with every incoming event. The optimal translation is then computed in closed form, while the desired rotation is given by the evolution of a virtual mechanical system whose energy is proven to be equal to the error function. This allows for a simple yet robust solution of the problem, showing how event-based vision can simplify computer vision tasks. The approach takes full advantage of the high temporal resolution of the sensor, as the estimated pose is incrementally updated with every incoming event. Two approaches are proposed: the Full and the Efficient methods. These two methods are compared against a state of the art PnP algorithm both on synthetic and on real data, producing similar accuracy in addition of being faster.

  13. Improvement of glucose uptake rate and production of target chemicals by overexpressing hexose transporters and transcriptional activator Gcr1 in Saccharomyces cerevisiae.

    PubMed

    Kim, Daehee; Song, Ji-Yoon; Hahn, Ji-Sook

    2015-12-01

    Metabolic engineering to increase the glucose uptake rate might be beneficial to improve microbial production of various fuels and chemicals. In this study, we enhanced the glucose uptake rate in Saccharomyces cerevisiae by overexpressing hexose transporters (HXTs). Among the 5 tested HXTs (Hxt1, Hxt2, Hxt3, Hxt4, and Hxt7), overexpression of high-affinity transporter Hxt7 was the most effective in increasing the glucose uptake rate, followed by moderate-affinity transporters Hxt2 and Hxt4. Deletion of STD1 and MTH1, encoding corepressors of HXT genes, exerted differential effects on the glucose uptake rate, depending on the culture conditions. In addition, improved cell growth and glucose uptake rates could be achieved by overexpression of GCR1, which led to increased transcription levels of HXT1 and ribosomal protein genes. All genetic modifications enhancing the glucose uptake rate also increased the ethanol production rate in wild-type S. cerevisiae. Furthermore, the growth-promoting effect of GCR1 overexpression was successfully applied to lactic acid production in an engineered lactic acid-producing strain, resulting in a significant improvement of productivity and titers of lactic acid production under acidic fermentation conditions. PMID:26431967

  14. The Effects of Age and Cue-Action Reminders on Event-Based Prospective Memory Performance in Preschoolers

    ERIC Educational Resources Information Center

    Kliegel, Matthias; Jager, Theodor

    2007-01-01

    The present study investigated event-based prospective memory in five age groups of preschoolers (i.e., 2-, 3-, 4-, 5-, and 6-year-olds). Applying a laboratory-controlled prospective memory procedure, the data showed that event-based prospective memory performance improves across the preschool years, at least between 3 and 6 years of age. However,

  15. Measuring pesticides in surface waters - continuous versus event-based sampling design

    NASA Astrophysics Data System (ADS)

    Eyring, J.; Bach, M.; Frede, H.-G.

    2009-04-01

    Monitoring pesticides in surface waters is still a work- and cost-intensive procedure. Therefore, studies are normally carried out with a low monitoring frequency or with only a small selection of substances to be analyzed. In this case, it is not possible to picture the high temporal variability of pesticide concentrations, depending on application dates, weather conditions, cropping seasons and other factors. In 2007 the Institute of Landscape Ecology and Resource Management at Giessen University implemented a monitoring program during two pesticide application periods aiming to produce a detailed dataset of pesticide concentration for a wide range of substances, and which would also be suitable for the evaluation of catchment-scale pesticide exposure models. The Weida catchment in Thuringia (Eastern Germany) was selected as study area due to the availability of detailed pesticide application data for this region. The samples were taken from the river Weida at the gauge Zeulenroda, where it flows into a drinking water reservoir. The catchment area is 102 km². 67% of the area are in agricultural use, the main crops being winter wheat, maize, winter barley and winter rape. Dominant soil texture classes are loamy sand and loamy silt. About one third of the agricultural area is drained. The sampling was carried out in cooperation with the water supply agency of Thuringia (Fernwasserversorgung Thueringen). The sample analysis was done by the Institute of Environmental Research at Dortmund University. Two sampling schemes were carried out using two automatic samplers: continuous sampling with composite samples bottled two times per week and event-based sampling triggered by a discharge threshold. 53 samples from continuous sampling were collected. 19 discharge events were sampled with 45 individual samples (one to six per event). 34 pesticides and two metabolites were analyzed. 21 compounds were detected, nine of which having concentrations above the drinking water limit (0.1 µg/l). Pesticide loads were calculated separately from continuous and event-based samples. Only three pesticides dominated the total load. These were the herbicides metazachlor, terbuthylazine and quinmerac amounting to 75 % of the total load. This result seems to be plausible considering the fact that these three substances are the pesticides with the highest applied amounts in the Weida catchment. The highest pesticide loads of single pesticides were observed during or shortly after their application period, mostly accompanied by larger discharge events. They can be explained as surface runoff and drainage inputs from treated fields, since spray-drift inputs would be detected during the application periods without dependency on discharge events, and inputs from point-sources are usually independent of discharge as well. Annual loads calculated from continuous samples were mainly higher than those of event-based samples due to the fact that they represent a much longer time period. On the other hand, the highest concentrations were found in the event-based samples; in many cases they double the maximum concentrations of continuous samples. The monitoring study presented shows that different sampling strategies lead to different results and can answer different questions. If the intention is to detect maximum concentrations caused by surface runoff or drainage inputs, e.g. to assess the resulting risk to the aquatic community, the event based sampling method can be recommended. If one is rather interested in calculating annual pesticide loads and assessing which fractions of applied amounts finally enter the surface water network, continuous sampling is advisable. The dataset of continuous and event-based pesticide concentrations offers the possibility to evaluate and improve pesticide exposure models at the catchment scale. Further work is scheduled on this issue.

  16. NASA Space Radiation Program Integrative Risk Model Toolkit

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; Hu, Shaowen; Plante, Ianik; Ponomarev, Artem L.; Sandridge, Chris

    2015-01-01

    NASA Space Radiation Program Element scientists have been actively involved in development of an integrative risk models toolkit that includes models for acute radiation risk and organ dose projection (ARRBOD), NASA space radiation cancer risk projection (NSCR), hemocyte dose estimation (HemoDose), GCR event-based risk model code (GERMcode), and relativistic ion tracks (RITRACKS), NASA radiation track image (NASARTI), and the On-Line Tool for the Assessment of Radiation in Space (OLTARIS). This session will introduce the components of the risk toolkit with opportunity for hands on demonstrations. The brief descriptions of each tools are: ARRBOD for Organ dose projection and acute radiation risk calculation from exposure to solar particle event; NSCR for Projection of cancer risk from exposure to space radiation; HemoDose for retrospective dose estimation by using multi-type blood cell counts; GERMcode for basic physical and biophysical properties for an ion beam, and biophysical and radiobiological properties for a beam transport to the target in the NASA Space Radiation Laboratory beam line; RITRACKS for simulation of heavy ion and delta-ray track structure, radiation chemistry, DNA structure and DNA damage at the molecular scale; NASARTI for modeling of the effects of space radiation on human cells and tissue by incorporating a physical model of tracks, cell nucleus, and DNA damage foci with image segmentation for the automated count; and OLTARIS, an integrated tool set utilizing HZETRN (High Charge and Energy Transport) intended to help scientists and engineers study the effects of space radiation on shielding materials, electronics, and biological systems.

  17. Lessons Learned from Real-Time, Event-Based Internet Science Communications

    NASA Technical Reports Server (NTRS)

    Phillips, T.; Myszka, E.; Gallagher, D. L.; Adams, M. L.; Koczor, R. J.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    For the last several years the Science Directorate at Marshall Space Flight Center has carried out a diverse program of Internet-based science communication. The Directorate's Science Roundtable includes active researchers, NASA public relations, educators, and administrators. The Science@NASA award-winning family of Web sites features science, mathematics, and space news. The program includes extended stories about NASA science, a curriculum resource for teachers tied to national education standards, on-line activities for students, and webcasts of real-time events. The focus of sharing science activities in real-time has been to involve and excite students and the public about science. Events have involved meteor showers, solar eclipses, natural very low frequency radio emissions, and amateur balloon flights. In some cases, broadcasts accommodate active feedback and questions from Internet participants. Through these projects a pattern has emerged in the level of interest or popularity with the public. The pattern differentiates projects that include science from those that do not, All real-time, event-based Internet activities have captured public interest at a level not achieved through science stories or educator resource material exclusively. The worst event-based activity attracted more interest than the best written science story. One truly rewarding lesson learned through these projects is that the public recognizes the importance and excitement of being part of scientific discovery. Flying a camera to 100,000 feet altitude isn't as interesting to the public as searching for viable life-forms at these oxygen-poor altitudes. The details of these real-time, event-based projects and lessons learned will be discussed.

  18. Event-Based Parareal: A data-flow based implementation of parareal

    SciTech Connect

    Berry, Lee A; Elwasif, Wael R; Reynolds-Barredo, J.; Samaddar, D.; Sanchez, R.; Newman, David E; Chen, J.

    2012-01-01

    Parareal is an iterative algorithm that, in effect, achieves temporal decomposition for a time-dependent system of differential or partial differential equations. A solution is obtained in a shorter wall-clock time, but at the expense of increased compute cycles. The algorithm combines a fine solver that solves the system to acceptable accuracy with an approximate coarse solver. The critical task for the successful implementation of parareal on any system is the development of a coarse solver that leads to convergence in a small number of iterations compared to the number of time slices in the full time interval, and is, at the same time, much faster than the fine solver. Fast coarse solvers may not lead to sufficiently rapid convergence, and slow coarse solvers may not lead to significant gains even if the number of iterations to convergence is satisfactory. We find that the difficulty of meeting these conflicting demands can be substantially eased by using a data-driven, event-based implementation of parareal instead of the conventional algorithm where solver tasks are executed sequentially. For given convergence properties, the event-based approach relaxes the speed requirements on the coarse solver by a factor of , where is the number of iterations required for a converged solution. This may, for many problems, lead to an efficient parareal implementation that would otherwise not be possible or would require substantial coarse solver development.

  19. Event-based Plausibility Immediately Influences On-line Language Comprehension

    PubMed Central

    Matsuki, Kazunaga; Chow, Tracy; Hare, Mary; Elman, Jeffrey L.; Scheepers, Christoph; McRae, Ken

    2011-01-01

    In some theories of sentence comprehension, linguistically-relevant lexical knowledge such as selectional restrictions is privileged in terms of the time-course of its access and influence. We examined whether event knowledge computed by combining multiple concepts can rapidly influence language understanding even in the absence of selectional restriction violations. Specifically, we investigated whether instruments can combine with actions to influence comprehension of ensuing patients. Instrument-verb-patient triplets were created in a norming study designed to tap directly into event knowledge. In self-paced reading (Experiment 1), participants were faster to read patient nouns such as hair when they were typical of the instrument-action pair (Donna used the shampoo to wash vs. the hose to wash). Experiment 2 showed that these results were not due to direct instrument-patient relations. Experiment 3 replicated Experiment 1 using eyetracking, with effects of event typicality observed in first fixation and gaze durations on the patient noun. This research demonstrates that conceptual event-based expectations are computed and used rapidly and dynamically during on-line language comprehension. We discuss relationships among plausibility and predictability, as well as their implications. We conclude that selectional restrictions may be best considered as event-based conceptual knowledge, rather than lexical-grammatical knowledge. PMID:21517222

  20. Event-based and Multi Agent Control of an Innovative Wheelchair

    NASA Astrophysics Data System (ADS)

    Diomin, U.; Witczak, P.; Stetter, R.

    2015-11-01

    Due to the aging population more and more people require mobility assistance in form of a wheelchair. Generally it would be desirable that such wheelchairs would be easy to use and would allow their users the possibility to move in any direction at any time. Concepts which allow such movements are existing since many years but have for several reasons not found their way to the market. Additionally for semi-autonomous (assisted) operation and fully autonomous operation (e. g. an empty wheelchair driving to its charging station) the control task is much less challenging for such drive system, because no complex manoeuvres needs to be considered and planned. In an ongoing research a drive system for a wheelchair was developed which offers such possibilities employing a relatively simple mechanical design. This drive system is based on a certain steering principle which is based on torque differences between different wheels. This allows a relatively simple mechanical design but poses challenges on the control of the vehicle. This paper describes two possible approaches to address this challenge - the use of an event based control and the application of multiple software agents. Both approaches can solve the control problem individually but can also complement each other for better system performance. The paper stars with a description of the wheelchair drive system. Then the asynchronous event based control software is described as well the multi agent based approach. The next sections report the results of the experiments and discuss the further improvements.

  1. An efficient hybrid causative event-based approach for deriving the annual flood frequency distribution

    NASA Astrophysics Data System (ADS)

    Thyer, Mark; Li, Jing; Lambert, Martin; Kuczera, George; Metcalfe, Andrew

    2015-04-01

    Flood extremes are driven by highly variable and complex climatic and hydrological processes. Derived flood frequency methods are often used to predict the flood frequency distribution (FFD) because they can provide predictions in ungauged catchments and evaluate the impact of land-use or climate change. This study presents recent work on development of a new derived flood frequency method called the hybrid causative events (HCE) approach. The advantage of the HCE approach is that it combines the accuracy of the continuous simulation approach with the computational efficiency of the event-based approaches. Derived flood frequency methods, can be divided into two classes. Event-based approaches provide fast estimation, but can also lead to prediction bias due to limitations of inherent assumptions required for obtaining input information (rainfall and catchment wetness) for events that cause large floods. Continuous simulation produces more accurate predictions, however, at the cost of massive computational time. The HCE method uses a short continuous simulation to provide inputs for a rainfall-runoff model running in an event-based fashion. A proof-of-concept pilot study that the HCE produces estimates of the flood frequency distribution with similar accuracy as the continuous simulation, but with dramatically reduced computation time. Recent work incorporated seasonality into the HCE approach and evaluated with a more realistic set of eight sites from a wide range of climate zones, typical of Australia, using a virtual catchment approach. The seasonal hybrid-CE provided accurate predictions of the FFD for all sites. Comparison with the existing non-seasonal hybrid-CE showed that for some sites the non-seasonal hybrid-CE significantly over-predicted the FFD. Analysis of the underlying cause of whether a site had a high, low or no need to use seasonality found it was based on a combination of reasons, that were difficult to predict apriori. Hence it is recommended that the seasonal hybrid-CE be used as it provided accurate predictions for all sites. The evaluation of the HCE on a wide range of climatology's, including Mediterranean, temperate, sub-tropical/tropical and desert provide greater confidence that it provides an accurate and efficient method for predicting the FFD.

  2. An event based real-time conditioned predictor of hourly hyetograph characteristics

    NASA Astrophysics Data System (ADS)

    Giorgio, Massimiliano; Greco, Roberto

    2010-05-01

    Setting up stochastic models capable to perform real-time conditioned rainfall predictions at high temporal resolution is crucial in developing hydro-geological early warning systems. Indeed, several rainfall-induced dangerous phenomena taking place at catchment or slope scale, such as flash floods and debris flows, may be triggered by relatively short rainfall events. The small spatial resolution at which the predictions are needed does not allow to make use neither of rainfall forecasts based on global circulation models, nor of data coming from radar sensors. Thus, the most reliable source of information is still represented by rain gauges installed at the site to be monitored. Modelling of point rainfall series has been addressed in hydrological literature with two major approaches: cluster-based models and event-based models. In this paper, using rainfall data observed in real time during a storm, a stochastic predictor of its future evolution is presented. The core of the predictor consists in an event based stochastic model. An event based approach is adopted, since it permits to identify a storm on the basis of the observed series of rainfall data and to calculate univocally its probability, thus allowing to perform the desired predictions in a relatively straightforward way. With this approach, predictions can be conditioned only to the part of real time observed rainfall data on which future evolution of the storm depends, in the stochastic sense. Conversely, cluster-based stochastic models, widely used for the generation of synthetic rainfall series, are not trivially suitable for real-time conditioned predictions, since they do not allow to evaluate unambiguously the probability of an observed hyetograph, because it can be generated by more than one combination of rain cells. The proposed model has been calibrated with hourly rainfall series of the rain gauges of the meteorological alert network of the Civil Protection Agency of Campania, Southern Italy. The statistical hypotheses on which the model is based have been checked by classical statistical tests, such as Blum-Kiefer-Rosenblatt test for independence. Furthermore, the information about the observed internal structure of the storm, at hourly scale, has been coupled with the external structure model, allowing to perform conditioned predictions of hydrologic response indexes, depending on the future evolution of hyetograph shape.

  3. Event based self-supervised temporal integration for multimodal sensor data.

    PubMed

    Barakova, Emilia I; Lourens, Tino

    2005-06-01

    A method for synergistic integration of multimodal sensor data is proposed in this paper. This method is based on two aspects of the integration process: (1) achieving synergistic integration of two or more sensory modalities, and (2) fusing the various information streams at particular moments during processing. Inspired by psychophysical experiments, we propose a self-supervised learning method for achieving synergy with combined representations. Evidence from temporal registration and binding experiments indicates that different cues are processed individually at specific time intervals. Therefore, an event-based temporal co-occurrence principle is proposed for the integration process. This integration method was applied to a mobile robot exploring unfamiliar environments. Simulations showed that integration enhanced route recognition with many perceptual similarities; moreover, they indicate that a perceptual hierarchy of knowledge about instant movement contributes significantly to short-term navigation, but that visual perceptions have bigger impact over longer intervals. PMID:15988800

  4. EQRM: An open-source event-based earthquake risk modeling program

    NASA Astrophysics Data System (ADS)

    Robinson, D. J.; Dhu, T.; Row, P.

    2007-12-01

    Geoscience Australia's Earthquake Risk Model (EQRM) is an event-based tool for earthquake scenario ground motion and scenario loss modeling as well as probabilistic seismic hazard (PSHA) and risk (PSRA) modeling. It has been used to conduct PSHA and PSRA for many of Australia's largest cities and it has become an important tool for the emergency management community which use it for scneario response planning. It has the potential to link with earthquake monitoring programs to provide automatic loss estimates from network recorded events. An open-source alpha-release version of the software is freely available on SourceForge. It can be used for hazard or risk analyses in any region of the world by supplying appropriately formatted input files. Source code is also supplied so advanced users can modify individual components to suit their needs.

  5. Qualitative Event-Based Diagnosis: Case Study on the Second International Diagnostic Competition

    NASA Technical Reports Server (NTRS)

    Daigle, Matthew; Roychoudhury, Indranil

    2010-01-01

    We describe a diagnosis algorithm entered into the Second International Diagnostic Competition. We focus on the first diagnostic problem of the industrial track of the competition in which a diagnosis algorithm must detect, isolate, and identify faults in an electrical power distribution testbed and provide corresponding recovery recommendations. The diagnosis algorithm embodies a model-based approach, centered around qualitative event-based fault isolation. Faults produce deviations in measured values from model-predicted values. The sequence of these deviations is matched to those predicted by the model in order to isolate faults. We augment this approach with model-based fault identification, which determines fault parameters and helps to further isolate faults. We describe the diagnosis approach, provide diagnosis results from running the algorithm on provided example scenarios, and discuss the issues faced, and lessons learned, from implementing the approach

  6. Pinning cluster synchronization in an array of coupled neural networks under event-based mechanism.

    PubMed

    Li, Lulu; Ho, Daniel W C; Cao, Jinde; Lu, Jianquan

    2016-04-01

    Cluster synchronization is a typical collective behavior in coupled dynamical systems, where the synchronization occurs within one group, while there is no synchronization among different groups. In this paper, under event-based mechanism, pinning cluster synchronization in an array of coupled neural networks is studied. A new event-triggered sampled-data transmission strategy, where only local and event-triggering states are utilized to update the broadcasting state of each agent, is proposed to realize cluster synchronization of the coupled neural networks. Furthermore, a self-triggered pinning cluster synchronization algorithm is proposed, and a set of iterative procedures is given to compute the event-triggered time instants. Hence, this will reduce the computational load significantly. Finally, an example is given to demonstrate the effectiveness of the theoretical results. PMID:26829603

  7. On the Application of Different Event-Based Sampling Strategies to the Control of a Simple Industrial Process

    PubMed Central

    Sánchez, José; Guarnes, Miguel Ángel; Dormido, Sebastián

    2009-01-01

    This paper is an experimental study of the utilization of different event-based strategies for the automatic control of a simple but very representative industrial process: the level control of a tank. In an event-based control approach it is the triggering of a specific event, and not the time, that instructs the sensor to send the current state of the process to the controller, and the controller to compute a new control action and send it to the actuator. In the document, five control strategies based on different event-based sampling techniques are described, compared, and contrasted with a classical time-based control approach and a hybrid one. The common denominator in the time, the hybrid, and the event-based control approaches is the controller: a proportional-integral algorithm with adaptations depending on the selected control approach. To compare and contrast each one of the hybrid and the pure event-based control algorithms with the time-based counterpart, the two tasks that a control strategy must achieve (set-point following and disturbance rejection) are independently analyzed. The experimental study provides new proof concerning the ability of event-based control strategies to minimize the data exchange among the control agents (sensors, controllers, actuators) when an error-free control of the process is not a hard requirement. PMID:22399975

  8. Event-based surveillance in north-western Ethiopia: experience and lessons learnt in the field

    PubMed Central

    Ota, Masaki; Beyene, Belay Bezabih

    2015-01-01

    This study piloted an event-based surveillance system at the health centre (HC) level in Ethiopia. The system collects rumours in the community and registers them in rumour logbooks to record events of disease outbreaks and public health emergencies. Descriptive analysis was conducted on the events captured at the 59 study HCs in the Amhara Region in north-western Ethiopia between October 2013 and November 2014. A total of 126 rumours were registered at two thirds of the HCs during the study period. The average event reporting time was 3.8 days; response time of the HCs was 0.6 days, resulting in a total response time of 4.4 days. The most commonly reported rumours were measles-related (n = 90, 71%). These rumours followed a similar pattern of measles cases reported in the routine surveillance system. The largest proportion of rumours were reported by community members (n = 38, 36%) followed by health post workers (n = 36, 29%) who were normally informed by the community members about the rumours. This surveillance system was established along with an existing indicator-based surveillance system and was simple to implement. The implementation cost was minimal, requiring only printing and distribution of rumour logbooks to the HCs and brief orientations to focal persons. In countries where routine surveillance is still weak, an event-based surveillance system similar to this should be considered as a supplementary tool for disease monitoring. PMID:26668763

  9. Improvement of hydrological flood forecasting through an event based output correction method

    NASA Astrophysics Data System (ADS)

    Klotz, Daniel; Nachtnebel, Hans Peter

    2014-05-01

    This contribution presents an output correction method for hydrological models. A conceptualisation of the method is presented and tested in an alpine basin in Salzburg, Austria. The aim is to develop a method which is not prone to the drawbacks of autoregressive models. Output correction methods are an attractive option for improving hydrological predictions. They are complementary to the main modelling process and do not interfere with the modelling process itself. In general, output correction models estimate the future error of a prediction and use the estimation to improve the given prediction. Different estimation techniques are available dependent on the utilized information and the estimation procedure itself. Autoregressive error models are widely used for such corrections. Autoregressive models with exogenous inputs (ARX) allow the use of additional information for the error modelling, e.g. measurements from upper basins or predicted input-signals. Autoregressive models do however exhibit deficiencies, since the errors of hydrological models do generally not behave in an autoregressive manner. The decay of the error is usually different from an autoregressive function and furthermore the residuals exhibit different patterns under different circumstances. As for an example, one might consider different error-propagation behaviours under high- and low-flow situations or snow melt driven conditions. This contribution presents a conceptualisation of an event-based correction model and focuses on flood events only. The correction model uses information about the history of the residuals and exogenous variables to give an error-estimation. The structure and parameters of the correction models can be adapted to given event classes. An event-class is a set of flood events that exhibit a similar pattern for the residuals or the hydrological conditions. In total, four different event-classes have been identified in this study. Each of them represents a different hydrological state, which is associated with different error sources and behaviours. Within each event-class, a set of ARX models are applied to simulate the behaviour of the error. This approach makes the correction model highly adaptable and allows for the representation of different behavioural patterns of the error. The procedure is tested and compared with an auto regressive model of first order. It is shown that the event-based correction method can improve the prediction significantly, given that an event is classified correctly.

  10. Too exhausted to remember: ego depletion undermines subsequent event-based prospective memory.

    PubMed

    Li, Jian-Bin; Nie, Yan-Gang; Zeng, Min-Xia; Huntoon, Meghan; Smith, Jessi L

    2013-01-01

    Past research has consistently found that people are likely to do worse on high-level cognitive tasks after exerting self-control on previous actions. However, little has been unraveled about to what extent ego depletion affects subsequent prospective memory. Drawing upon the self-control strength model and the relationship between self-control resources and executive control, this study proposes that the initial actions of self-control may undermine subsequent event-based prospective memory (EBPM). Ego depletion was manipulated through watching a video requiring visual attention (Experiment 1) or completing an incongruent Stroop task (Experiment 2). Participants were then tested on EBPM embedded in an ongoing task. As predicted, the results showed that after ruling out possible intervening variables (e.g. mood, focal and nonfocal cues, and characteristics of ongoing task and ego depletion task), participants in the high-depletion condition performed significantly worse on EBPM than those in the low-depletion condition. The results suggested that the effect of ego depletion on EBPM was mainly due to an impaired prospective component rather than to a retrospective component. PMID:23432682

  11. Can readers ignore implausibility? Evidence for nonstrategic monitoring of event-based plausibility in language comprehension.

    PubMed

    Isberner, Maj-Britt; Richter, Tobias

    2013-01-01

    We present evidence for a nonstrategic monitoring of event-based plausibility during language comprehension by showing that readers cannot ignore the implausibility of information even if it is detrimental to the task at hand. In two experiments using a Stroop-like paradigm, participants were required to provide positive and negative responses independent of plausibility in an orthographical task (Experiment 1) or a nonlinguistic color judgment task (Experiment 2) to target words that were either plausible or implausible in their context. We expected a nonstrategic assessment of plausibility to interfere with positive responses to implausible words. ANOVAs and linear mixed models analyses of the response latencies revealed a significant interaction of plausibility and required response that supported this prediction in both experiments, despite the use of two very different tasks. Moreover, it could be shown that the effect was not driven by the differential predictability of plausible and implausible words. These results suggest that plausibility monitoring is an inherent component of information processing. PMID:23165201

  12. Event-based surveillance in Papua New Guinea: strengthening an International Health Regulations (2005) core capacity.

    PubMed

    Dagina, Rosheila; Murhekar, Manoj; Rosewell, Alexander; Pavlin, Boris I

    2013-01-01

    Under the International Health Regulations (2005), Member States are required to develop capacity in event-based surveillance (EBS). The Papua New Guinea National Department of Health established an EBS system during the influenza pandemic in August 2009. We review its performance from August 2009 to November 2012, sharing lessons that may be useful to other low-resource public health practitioners working in surveillance. We examined the EBS system's event reporting, event verification and response. Characteristics examined included type of event, source of information, timeliness, nature of response and outcome. Sixty-one records were identified. The median delay between onset of the event and date of reporting was 10 days. The largest proportion of reports (39%) came from Provincial Health Offices, followed by direct reports from clinical staff (25%) and reports in the media (11%). Most (84%) of the events were substantiated to be true public health events, and 56% were investigated by the Provincial Health Office alone. A confirmed or probable etiology could not be determined in 69% of true events. EBS is a simple strategy that forms a cornerstone of public health surveillance and response particularly in low-resource settings such as Papua New Guinea. There is a need to reinforce reporting pathways, improve timeliness of reporting, expand sources of information, improve feedback and improve diagnostic support capacity. For it to be successful, EBS should be closely tied to response. PMID:24319609

  13. Fluence-based and microdosimetric event-based methods for radiation protection in space

    NASA Technical Reports Server (NTRS)

    Curtis, Stanley B.; Meinhold, C. B. (Principal Investigator)

    2002-01-01

    The National Council on Radiation Protection and Measurements (NCRP) has recently published a report (Report #137) that discusses various aspects of the concepts used in radiation protection and the difficulties in measuring the radiation environment in spacecraft for the estimation of radiation risk to space travelers. Two novel dosimetric methodologies, fluence-based and microdosimetric event-based methods, are discussed and evaluated, along with the more conventional quality factor/LET method. It was concluded that for the present, any reason to switch to a new methodology is not compelling. It is suggested that because of certain drawbacks in the presently-used conventional method, these alternative methodologies should be kept in mind. As new data become available and dosimetric techniques become more refined, the question should be revisited and that in the future, significant improvement might be realized. In addition, such concepts as equivalent dose and organ dose equivalent are discussed and various problems regarding the measurement/estimation of these quantities are presented.

  14. Simulation of greenhouse climate monitoring and control with wireless sensor network and event-based control.

    PubMed

    Pawlowski, Andrzej; Guzman, Jose Luis; Rodríguez, Francisco; Berenguel, Manuel; Sánchez, José; Dormido, Sebastián

    2009-01-01

    Monitoring and control of the greenhouse environment play a decisive role in greenhouse production processes. Assurance of optimal climate conditions has a direct influence on crop growth performance, but it usually increases the required equipment cost. Traditionally, greenhouse installations have required a great effort to connect and distribute all the sensors and data acquisition systems. These installations need many data and power wires to be distributed along the greenhouses, making the system complex and expensive. For this reason, and others such as unavailability of distributed actuators, only individual sensors are usually located in a fixed point that is selected as representative of the overall greenhouse dynamics. On the other hand, the actuation system in greenhouses is usually composed by mechanical devices controlled by relays, being desirable to reduce the number of commutations of the control signals from security and economical point of views. Therefore, and in order to face these drawbacks, this paper describes how the greenhouse climate control can be represented as an event-based system in combination with wireless sensor networks, where low-frequency dynamics variables have to be controlled and control actions are mainly calculated against events produced by external disturbances. The proposed control system allows saving costs related with wear minimization and prolonging the actuator life, but keeping promising performance results. Analysis and conclusions are given by means of simulation results. PMID:22389597

  15. Selection of intense rainfall events based on intensity thresholds and lightning data in Switzerland

    NASA Astrophysics Data System (ADS)

    Gaal, L.; Molnar, P.; Szolgay, J.

    2014-01-01

    This paper presents a method to identify intense warm season storms of convective character based on intensity thresholds and lightning, and analyzes their statistical properties. Long records of precipitation and lightning data at 4 stations and 10 min resolution in different climatological regions in Switzerland are used. Our premise is that thunderstorms associated with lightning generate bursts of high rainfall intensity. We divided all storms into those accompanied by lightning and those without lightning and found the threshold I* that separates intense events based on peak 10 min intensity Ip ≥ I* for a chosen misclassification rate α. The performance and robustness of the selection method was tested by investigating the inter-annual variability of I* and its relation to the frequency of lightning strikes. The probability distributions of the main storm properties (rainfall depth R, event duration D, average storm intensity Ia and peak 10 min intensity Ip) for the intense storm subsets show that the event average and peak intensities are significantly different between the stations, and highest in Lugano in southern Switzerland. Non-parametric correlations between the main storm properties were estimated for the subsets of intense storms and all storms including stratiform rain. The differences in the correlations between storm subsets are greater than those between stations, which indicates that care must be exercised not to mix events when they are sampled for multivariate analysis, e.g. copula fitting to rainfall data.

  16. Selection of intense rainfall events based on intensity thresholds and lightning data in Switzerland

    NASA Astrophysics Data System (ADS)

    Gaál, L.; Molnar, P.; Szolgay, J.

    2014-05-01

    This paper presents a method to identify intense warm season storms with convective character based on intensity thresholds and the presence of lightning, and analyzes their statistical properties. Long records of precipitation and lightning data at 4 stations and 10 min resolution in different climatological regions in Switzerland are used. Our premise is that thunderstorms associated with lightning generate bursts of high rainfall intensity. We divided all recorded storms into those accompanied by lightning and those without lightning and found the threshold I* that separates intense events based on peak 10 min intensity Ip ≥ I* for a chosen misclassification rate α. The performance and robustness of the selection method was tested by investigating the inter-annual variability of I* and its relation to the frequency of lightning strikes. The probability distributions of the main storm properties (rainfall depth R, event duration D, average storm intensity Ia and peak 10 min intensity Ip) for the intense storm subsets show that the event average and peak intensities are significantly different between the stations. Non-parametric correlations between the main storm properties were estimated for intense storms and all storms including stratiform rain. The differences in the correlations between storm subsets are greater than those between stations, which indicates that care must be exercised not to mix events of different origin when they are sampled for multivariate analysis, for example, copula fitting to rainfall data.

  17. A Review of Evaluations of Electronic Event-Based Biosurveillance Systems

    PubMed Central

    Gajewski, Kimberly N.; Peterson, Amy E.; Chitale, Rohit A.; Pavlin, Julie A.; Russell, Kevin L.; Chretien, Jean-Paul

    2014-01-01

    Electronic event-based biosurveillance systems (EEBS’s) that use near real-time information from the internet are an increasingly important source of epidemiologic intelligence. However, there has not been a systematic assessment of EEBS evaluations, which could identify key uncertainties about current systems and guide EEBS development to most effectively exploit web-based information for biosurveillance. To conduct this assessment, we searched PubMed and Google Scholar to identify peer-reviewed evaluations of EEBS’s. We included EEBS’s that use publicly available internet information sources, cover events that are relevant to human health, and have global scope. To assess the publications using a common framework, we constructed a list of 17 EEBS attributes from published guidelines for evaluating health surveillance systems. We identified 11 EEBS’s and 20 evaluations of these EEBS’s. The number of published evaluations per EEBS ranged from 1 (Gen-Db, GODsN, MiTAP) to 8 (GPHIN, HealthMap). The median number of evaluation variables assessed per EEBS was 8 (range, 3–15). Ten published evaluations contained quantitative assessments of at least one key variable. No evaluations examined usefulness by identifying specific public health decisions, actions, or outcomes resulting from EEBS outputs. Future EEBS assessments should identify and discuss critical indicators of public health utility, especially the impact of EEBS’s on public health response. PMID:25329886

  18. On-Board Event-Based State Estimation for Trajectory Approaching and Tracking of a Vehicle

    PubMed Central

    Martínez-Rey, Miguel; Espinosa, Felipe; Gardel, Alfredo; Santos, Carlos

    2015-01-01

    For the problem of pose estimation of an autonomous vehicle using networked external sensors, the processing capacity and battery consumption of these sensors, as well as the communication channel load should be optimized. Here, we report an event-based state estimator (EBSE) consisting of an unscented Kalman filter that uses a triggering mechanism based on the estimation error covariance matrix to request measurements from the external sensors. This EBSE generates the events of the estimator module on-board the vehicle and, thus, allows the sensors to remain in stand-by mode until an event is generated. The proposed algorithm requests a measurement every time the estimation distance root mean squared error (DRMS) value, obtained from the estimator's covariance matrix, exceeds a threshold value. This triggering threshold can be adapted to the vehicle's working conditions rendering the estimator even more efficient. An example of the use of the proposed EBSE is given, where the autonomous vehicle must approach and follow a reference trajectory. By making the threshold a function of the distance to the reference location, the estimator can halve the use of the sensors with a negligible deterioration in the performance of the approaching maneuver. PMID:26102489

  19. Asynchronous Event-Based Multikernel Algorithm for High-Speed Visual Features Tracking.

    PubMed

    Lagorce, Xavier; Meyer, Cdric; Ieng, Sio-Hoi; Filliat, David; Benosman, Ryad

    2015-08-01

    This paper presents a number of new methods for visual tracking using the output of an event-based asynchronous neuromorphic dynamic vision sensor. It allows the tracking of multiple visual features in real time, achieving an update rate of several hundred kilohertz on a standard desktop PC. The approach has been specially adapted to take advantage of the event-driven properties of these sensors by combining both spatial and temporal correlations of events in an asynchronous iterative framework. Various kernels, such as Gaussian, Gabor, combinations of Gabor functions, and arbitrary user-defined kernels, are used to track features from incoming events. The trackers described in this paper are capable of handling variations in position, scale, and orientation through the use of multiple pools of trackers. This approach avoids the N(2) operations per event associated with conventional kernel-based convolution operations with N N kernels. The tracking performance was evaluated experimentally for each type of kernel in order to demonstrate the robustness of the proposed solution. PMID:25248193

  20. Event-based design tool for construction site erosion and sediment controls

    NASA Astrophysics Data System (ADS)

    Trenouth, William R.; Gharabaghi, Bahram

    2015-09-01

    This paper provides additional discussion surrounding the novel event-based soil loss models developed by Trenouth and Gharabaghi (2015) for the design of erosion and sediment controls (ESCs) for various phases of construction - from pre-development to post-development conditions. The datasets for the study were obtained from three Ontario sites - Greensborough, Cookstown, and Alcona - in addition to datasets mined from the literature for three additional sites - Treynor, Iowa, Coshocton, Ohio and Cordoba, Spain. Model performances were evaluated for each of the study sites, and quantified using commonly-reported statistics. This work is nested within a broader conceptual framework, which includes the estimation of ambient receiving water quality, the prediction of event mean runoff quality for a given design storm, and the calculation of the required level of protection using adequate ESCs to meet receiving water quality guidelines. These models allow design engineers and regulatory agencies to assess the potential risk of ecological damage to receiving waters due to inadequate soil erosion and sediment control practices using dynamic scenario forecasting when considering rapidly changing land use conditions during various phases of construction, typically for a 2- or 5-year design storm return period.

  1. Assessing the Continuum of Event-Based Biosurveillance Through an Operational Lens

    SciTech Connect

    Corley, Courtney D.; Lancaster, Mary J.; Brigantic, Robert T.; Chung, James S.; Walters, Ronald A.; Arthur, Ray; Bruckner-Lea, Cindy J.; Calapristi, Augustin J.; Dowling, Glenn; Hartley, David M.; Kennedy, Shaun; Kircher, Amy; Klucking, Sara; Lee, Eva K.; McKenzie, Taylor K.; Nelson, Noele P.; Olsen, Jennifer; Pancerella, Carmen M.; Quitugua, Teresa N.; Reed, Jeremy T.; Thomas, Carla S.

    2012-03-28

    This research follows the Updated Guidelines for Evaluating Public Health Surveillance Systems, Recommendations from the Guidelines Working Group, published by the Centers for Disease Control and Prevention nearly a decade ago. Since then, models have been developed and complex systems have evolved with a breadth of disparate data to detect or forecast chemical, biological, and radiological events that have significant impact in the One Health landscape. How the attributes identified in 2001 relate to the new range of event-based biosurveillance (EBB) technologies is unclear. This manuscript frames the continuum of EBB methods, models, and constructs through an operational lens (i.e., aspects and attributes associated with operational considerations in the development, testing, and validation of the EBB methods and models and their use in an operational environment). A 2-day subject matter expert workshop was held to scientifically identify, develop, and vet a set of attributes for the broad range of such operational considerations. Workshop participants identified and described comprehensive attributes for the characterization of EBB. The identified attributes are: (1) event, (2) readiness, (3) operational aspects, (4) geographic coverage, (5) population coverage, (6) input data, (7) output, and (8) cost. Ultimately, the analyses herein discuss the broad scope, complexity, and relevant issues germane to EBB useful in an operational environment.

  2. An event-based approach for examining the effects of wildland fire decisions on communities.

    PubMed

    McCool, Stephen F; Burchfield, James A; Williams, Daniel R; Carroll, Matthew S

    2006-04-01

    Public concern over the consequences of forest fire to wildland interface communities has led to increased resources devoted to fire suppression, fuel treatment, and management of fire events. The social consequences of the decisions involved in these and other fire-related actions are largely unknown, except in an anecdotal sense, but do occur at a variety of temporal and social organizational scales. These consequences are not limited to the fire event itself. Preparation for the possibility of a fire, actions that suppression agencies take during a fire, and postfire decisions all have consequences, if unknown currently. This article presents an "event-based" approach that can be useful for constructing and systematic discussion about the consequences of wildland fire to human communities. For each of the three major periods within this approach, agencies, communities, and individuals make decisions and take actions that have consequences. The article presents an integrated, temporally based process for examining these consequences, which is similar to others developed in the natural hazards and disaster management literature. PMID:16465562

  3. On-Board Event-Based State Estimation for Trajectory Approaching and Tracking of a Vehicle.

    PubMed

    Martínez-Rey, Miguel; Espinosa, Felipe; Gardel, Alfredo; Santos, Carlos

    2015-01-01

    For the problem of pose estimation of an autonomous vehicle using networked external sensors, the processing capacity and battery consumption of these sensors, as well as the communication channel load should be optimized. Here, we report an event-based state estimator (EBSE) consisting of an unscented Kalman filter that uses a triggering mechanism based on the estimation error covariance matrix to request measurements from the external sensors. This EBSE generates the events of the estimator module on-board the vehicle and, thus, allows the sensors to remain in stand-by mode until an event is generated. The proposed algorithm requests a measurement every time the estimation distance root mean squared error (DRMS) value, obtained from the estimator's covariance matrix, exceeds a threshold value. This triggering threshold can be adapted to the vehicle's working conditions rendering the estimator even more efficient. An example of the use of the proposed EBSE is given, where the autonomous vehicle must approach and follow a reference trajectory. By making the threshold a function of the distance to the reference location, the estimator can halve the use of the sensors with a negligible deterioration in the performance of the approaching maneuver. PMID:26102489

  4. Simulation of Greenhouse Climate Monitoring and Control with Wireless Sensor Network and Event-Based Control

    PubMed Central

    Pawlowski, Andrzej; Guzman, Jose Luis; Rodríguez, Francisco; Berenguel, Manuel; Sánchez, José; Dormido, Sebastián

    2009-01-01

    Monitoring and control of the greenhouse environment play a decisive role in greenhouse production processes. Assurance of optimal climate conditions has a direct influence on crop growth performance, but it usually increases the required equipment cost. Traditionally, greenhouse installations have required a great effort to connect and distribute all the sensors and data acquisition systems. These installations need many data and power wires to be distributed along the greenhouses, making the system complex and expensive. For this reason, and others such as unavailability of distributed actuators, only individual sensors are usually located in a fixed point that is selected as representative of the overall greenhouse dynamics. On the other hand, the actuation system in greenhouses is usually composed by mechanical devices controlled by relays, being desirable to reduce the number of commutations of the control signals from security and economical point of views. Therefore, and in order to face these drawbacks, this paper describes how the greenhouse climate control can be represented as an event-based system in combination with wireless sensor networks, where low-frequency dynamics variables have to be controlled and control actions are mainly calculated against events produced by external disturbances. The proposed control system allows saving costs related with wear minimization and prolonging the actuator life, but keeping promising performance results. Analysis and conclusions are given by means of simulation results. PMID:22389597

  5. A coupled model of TiN inclusion growth in GCr15SiMn during solidification in the electroslag remelting process

    NASA Astrophysics Data System (ADS)

    Yang, Liang; Cheng, Guo-guang; Li, Shi-jian; Zhao, Min; Feng, Gui-ping; Li, Tao

    2015-12-01

    TiN inclusions observed in an ingot produced by electroslag remelting (ESR) are extremely harmful to GCr15SiMn steel. Therefore, accurate predictions of the growth size of these inclusions during steel solidification are significant for clean ESR ingot production. On the basis of our previous work, a coupled model of solute microsegregation and TiN inclusion growth during solidification has been established. The results demonstrate that compared to a non-coupled model, the coupled model predictions of the size of TiN inclusions are in good agreement with experimental results using scanning electron microscopy with energy disperse spectroscopy (SEM-EDS). Because of high cooling rate, the sizes of TiN inclusions in the edge area of the ingots are relatively small compared to the sizes in the center area. During the ESR process, controlling the content of Ti in the steel is a feasible and effective method of decreasing the sizes of TiN inclusions.

  6. Coupling urban event-based and catchment continuous modelling for combined sewer overflow river impact assessment

    NASA Astrophysics Data System (ADS)

    Andrés-Doménech, I.; Múnera, J. C.; Francés, F.; Marco, J. B.

    2010-05-01

    Since the Water Framework Directive (WFD) was passed in year 2000, the protection of water bodies in the EU must be understood in a completely different way. Regarding to combined sewer overflows (CSOs) from urban drainage networks, the WFD implies that CSOs cannot be accepted because of their intrinsic features, but must be assessed for their impact on the receiving water bodies in agreement with specific environmental aims. Consequently, both, the urban system and the receiving one must be jointly analysed to evaluate their impact. In this context, a coupled scheme is presented in this paper to assess the CSOs impact in a river system in Torrelavega (Spain). First, an urban model is developed to characterise statistically the CSOs frequency, volume and duration. The main feature of this first model is the fact of being event-based: the system is modelled with some built synthetic storms which cover adequately the probability range of the main rainfall descriptors, i.e., rainfall event volume and peak intensity. Thus, CSOs are characterised in terms of their occurrence probability. Secondly, a continuous and distributed basin model is built to assess the river response at different points in the river network. This model was calibrated initially on a daily scale and downscaled later to the hourly scale. The main objective of this second element of the scheme is to provide the most likely state of the receiving river when a CSO occurs. By combining results of both models, CSO and river flows are homogeneously characterised from a statistical point of view. Finally, results from both models were coupled to estimate the final concentration of some analysed pollutants (the biochemical oxygen demand, BOD, and the total ammonium, NH4+), in the river just after the spills.

  7. Coupling urban event-based and catchment continuous modelling for combined sewer overflow river impact assessment

    NASA Astrophysics Data System (ADS)

    Andrés-Doménech, I.; Múnera, J. C.; Francés, F.; Marco, J. B.

    2010-10-01

    Since Water Framework Directive (WFD) was passed in year 2000, the conservation of water bodies in the EU must be understood in a completely different way. Regarding to combined sewer overflows (CSOs) from urban drainage networks, the WFD implies that we cannot accept CSOs because of their intrinsic features, but they must be assessed for their impact on the receiving water bodies in agreement with specific environmental aims. Consequently, both, urban system and the receiving water body must be jointly analysed to evaluate the environmental impact generated on the latter. In this context, a coupled scheme is presented in this paper to assess the CSOs impact on a river system in Torrelavega (Spain). First, a urban model is developed to statistically characterise the CSOs frequency, volume and duration. The main feature of this first model is the fact of being event-based: the system is modelled with some built synthetic storms which cover adequately the probability range of the main rainfall descriptors, i.e., rainfall event volume and peak intensity. Thus, CSOs are characterised in terms of their occurrence probability. Secondly, a continuous and distributed basin model is built to assess river response at different points in the river network. This model was calibrated initially on a daily scale and downscaled later to hourly scale. The main objective of this second element of the scheme is to provide the most likely state of the receiving river when a CSO occurs. By combining results of both models, CSO and river flows are homogeneously characterised from a statistical point of view. Finally, results from both models were coupled to estimate the final concentration of some analysed pollutants (biochemical oxygen demand, BOD, and total ammonium, NH4+), within the river just after the spills.

  8. Advanced Science/Event-based Data Service Framework at GES DISC

    NASA Astrophysics Data System (ADS)

    Shie, C. L.; Shen, S.; Kempler, S. J.

    2014-12-01

    The NASA Goddard Earth Sciences Data and Information Service Center (GES DISC) has provided numerous Earth science data, information, and services to various research communities and general publics for decades. To maintain an overall fine service including improving serving our users with advanced data services has been our primary goal. We are developing an advanced science/event-based data service framework. The framework aims to effectively provide users with a sophisticatedly integrated data package via user-friendly discovering and selecting a system-preset science/event topic (e.g., hurricane, volcano, etc.) from an in-developing knowledge database of the framework. A data recipe page related to the Hurricane topic has been developed to demo the concept. More showcases of various subjects such as Volcano, Dust Storm, and Forest Fire are also under development. This framework is in developing on top of existing data services at GES DISC, such as Mirador (data search engine), Giovanni (visualization), OPeNDAP, and data recipes. It also involves other data tools, such as Panoply, GrADS, IDL, etc. The Hurricane Sandy (Oct 22-31 2012) event is used here for a sample description. As Hurricane Sandy being selected as a user case, a table containing nine system-preset data variables (i.e., precipitation, winds, sea surface temperature, sea level pressure, air temperature, relative humidity, aerosols, soil moisture and surface runoff, and trace gases) linked to the respective data products with fine temporal and spatial resolutions from various in-house sources is provided. The "bundled" variable data can thus be readily downloaded through Mirador. The in-house Giovanni is accessible for users to acquire quick views of Level 3 (gridded) variables. For Level 2 (swath) or the Giovanni-unavailable Level 3 data, the system provides a link to data recipes that give a how-to guide to read and visualize the data using offline tools, such as Panoply, GrADS, or IDL.

  9. A Neuromorphic Event-Based Neural Recording System for Smart Brain-Machine-Interfaces.

    PubMed

    Corradi, Federico; Indiveri, Giacomo

    2015-10-01

    Neural recording systems are a central component of Brain-Machince Interfaces (BMIs). In most of these systems the emphasis is on faithful reproduction and transmission of the recorded signal to remote systems for further processing or data analysis. Here we follow an alternative approach: we propose a neural recording system that can be directly interfaced locally to neuromorphic spiking neural processing circuits for compressing the large amounts of data recorded, carrying out signal processing and neural computation to extract relevant information, and transmitting only the low-bandwidth outcome of the processing to remote computing or actuating modules. The fabricated system includes a low-noise amplifier, a delta-modulator analog-to-digital converter, and a low-power band-pass filter. The bio-amplifier has a programmable gain of 45-54 dB, with a Root Mean Squared (RMS) input-referred noise level of 2.1 μV, and consumes 90 μW . The band-pass filter and delta-modulator circuits include asynchronous handshaking interface logic compatible with event-based communication protocols. We describe the properties of the neural recording circuits, validating them with experimental measurements, and present system-level application examples, by interfacing these circuits to a reconfigurable neuromorphic processor comprising an array of spiking neurons with plastic and dynamic synapses. The pool of neurons within the neuromorphic processor was configured to implement a recurrent neural network, and to process the events generated by the neural recording system in order to carry out pattern recognition. PMID:26513801

  10. On the Relationship Between Effort Toward an Ongoing Task and Cue Detection in Event-Based Prospective Memory

    ERIC Educational Resources Information Center

    Marsh, Richard L.; Hicks, Jason L.; Cook, Gabriel I.

    2005-01-01

    In recent theories of event-based prospective memory, researchers have debated what degree of resources are necessary to identify a cue as related to a previously established intention. In order to simulate natural variations in attention, the authors manipulated effort toward an ongoing cognitive task in which intention-related cues were embedded…

  11. Modulation of a Fronto-Parietal Network in Event-Based Prospective Memory: An rTMS Study

    ERIC Educational Resources Information Center

    Bisiacchi, P. S.; Cona, G.; Schiff, S.; Basso, D.

    2011-01-01

    Event-based prospective memory (PM) is a multi-component process that requires remembering the delayed execution of an intended action in response to a pre-specified PM cue, while being actively engaged in an ongoing task. Some neuroimaging studies have suggested that both prefrontal and parietal areas are involved in the maintenance and…

  12. Comparison of event-based landslide inventory maps obtained interpreting satellite images and aerial photographs

    NASA Astrophysics Data System (ADS)

    Fiorucci, Federica; Cardinali, Mauro; Carlà Roberto; Mondini, Alessandro; Santurri, Leonardo; Guzzetti, Fausto

    2010-05-01

    Landslide inventory maps are a common type of map used for geomorphological investigations, land planning, and hazard and risk assessment. Landslide inventory maps covering medium to large areas are obtained primarily exploiting traditional geomorphological techniques. These techniques combine the visual and heuristic interpretation of stereoscopic aerial photographs with more or less extensive field investigations. Aerial photographs most commonly used to prepare landslide inventory maps range in scale from about 1:10,000 to about 1:40,000. Interpretation of satellite images is a relatively recent, powerful tool to obtain information of the Earth surface potentially useful for the production of landslide inventory maps. The usefulness of satellite information - and the associated technology - for the identification of landslides and the production of landslide inventory maps, remains largely unexplored. In this context, it is of interest to investigate the type, quantity, and quality of the information that can be retrieved analyzing images taken by the last generation of high and very-high resolution satellite sensors, and to compare this information with the information obtained from the analysis of traditional stereoscopic aerial photographs, or in the field. In the framework of the MORFEO project for the exploitation of Earth Observation data and technology for landslide identification and risk assessment, of the Italian Space Agency, we have compared two event-based landslide inventory maps prepared exploiting two different techniques. The two maps portray the geographical distribution and types of landslides triggered by rainfall in the period from November 2004 to May 2005 in the Collazzone area, Umbria, central Italy. The first map was prepared through reconnaissance field surveys carried out mostly along roads. The second map was obtained through the combined visual interpretation of 1:10,000 scale, colour ortho-photo maps, and images taken by the IKONOS high-resolution satellite. The comparison was executed considering: (i) descriptive landslide statistics, (ii) cartographic matching or mismatching, to quantify positional and dimensional errors (over-estimated or under-estimated landslide size), and (iii) differences in the frequency-area statistics, that quantify the number of landslides in different size classes. We discuss the results obtained in view of their importance for the production of landslide inventory maps. We emphasize advantages and limitations of the different information used, and of the adopted approaches and techniques.

  13. Event-based approach of downstream Rhône River flood regimes variability since 1982

    NASA Astrophysics Data System (ADS)

    Hénaff, Quentin; Arnaud-Fassetta, Gilles; Beltrando, Gérard

    2015-04-01

    Numerous downstream Rhône River floods have been recorded as catastrophic by French inter-ministerial order since the creation of natural disaster state recognition in 1982. Downstream Rhône River flood regimes, influenced by Mediterranean climate, are fundamentally affected by the spatio-temporal variability of rainfall events, especially in case of widespread flooding. Event-based analysis of cumulative rainfall data should allow us to characterise downstream Rhône River flood regimes variability by applying data mining methods to a spatio-temporal hydro-meteorological database. The first objective of this study is to determine if extreme rainfall events could be considered as geographical events, in other words if rainfall distribution is related to spatial processes. The proposed method is based on the measure of rainfall distribution spatial auto-correlation through the calculation of (i) Global Moran's index and (ii) the significance evaluation of that index with a z-score statistical test and its associated p-value. Secondly, cumulative rainfall data are integrated into a geo-event two-dimensional matrix: (i) cumulative rainfall per sub-catchment in row (spatial base unit) and (ii) cumulative rainfall per catastrophic event in column (temporal base unit). This matrix was co-clustered which allows simultaneous clustering of the rows (sub-catchment) and columns (events) by hierarchical clustering on principal components (HCPC) using Ward's method applying Euclidean Distance as similarity measure. Computing the Global Moran's index demonstrated a spatial aggregation tendency of rainfall distribution and the associated statistical test (z-core and p-value) noted the improbability of statistical evidence of random spatial pattern. Spatial variability of rainfall distribution is the result of two factors: rainfall event structure and rainfall event scale. The co-clustering geo-event matrix provided two co-clustering maps on two different cumulative rainfall distributions: (i) a reduced centered distribution of cumulative rainfall per sub-catchment (row) and (ii) a reduced centered distribution of cumulative rainfall per event (column). Both co-clustering maps are complementary to define spatio-temporal co-clusters. The geographical dimension of catastrophic hydro-meteorological events could be assessed by measuring and comparing the spatial auto-correlation of rainfall spatial distributions. These distributions were co-clustered to provide a geo-event typology of downstream Rhône River flood regimes. Moreover, these results show the interest of data mining methods to study spatio-temporal dimension of hydro-meteorological disasters.

  14. Incorporating seasonality into event-based joint probability methods for predicting flood frequency: A hybrid causative event approach

    NASA Astrophysics Data System (ADS)

    Li, Jing; Thyer, Mark; Lambert, Martin; Kuzera, George; Metcalfe, Andrew

    2016-02-01

    Flood extremes are driven by highly variable and complex climatic and hydrological processes. Observational evidence has identified that seasonality of climate variables has a major impact on flood peaks. However, event-based joint probability approaches for predicting the flood frequency distribution (FFD), which are commonly used in practice, do not commonly incorporate climate seasonality. This study presents an advance in event-based joint probability approaches by incorporating seasonality using the hybrid causative events (HCE) approach. The HCE was chosen because it uses the true causative events of the floods of interest and is able to combine the accuracy of continuous simulation with the computational efficiency of event-based approaches. The incorporation of seasonality is evaluated using a virtual catchment approach at eight sites over a wide range of Australian climate zones, including tropical, temperature, Mediterranean and desert climates (virtual catchment data for the eight sites is freely available via digital repository). The seasonal HCE provided accurate predictions of the FFD at all sites. In contrast, the non-seasonal HCE significantly over-predicted the FFD at some sites. The need to include seasonality was influenced by the magnitude of the seasonal variation in soil moisture and its coherence with the seasonal variation in extreme rainfall. For sites with a low seasonal variation in soil moisture the non-seasonal HCE provided reliable estimates of the FFD. For the remaining sites, it was found difficult to predict a priori whether ignoring seasonality provided a reliable estimate of the FFD, hence it is recommended that the seasonal HCE always be used. The practical implications of this study are that the HCE approach with seasonality is an accurate and efficient event-based joint probability approach to derive the flood frequency distribution across a wide range of climatologies.

  15. Effective utilization of flue gases in raceway reactor with event-based pH control for microalgae culture.

    PubMed

    Pawlowski, A; Mendoza, J L; Guzmán, J L; Berenguel, M; Acién, F G; Dormido, S

    2014-10-01

    This work addresses effective utilization of flue gases through the proper pH control in raceway reactors. The pH control problem has been addressed with an event-based control approach using a Generalized Predictive Controller (GPC) with actuator deadband. Applying this control strategy it is possible to reduce the control effort, and at the same time saving control resources. In the pH process case, the event-based controller with actuator deadband can be tuned to supply only necessary amount of CO2 to keep the pH close to its optimal value. On the other hand, the evaluated control algorithm significantly improves the pH control accuracy, what has a direct influence on biomass production. In order to test the performance of the event-based GPC controller, several experiments have been performed on a real raceway reactor. Additionally, several control performance indexes have been used to compare the analyzed technique with commonly used on/off controller. PMID:25113401

  16. Observer Agreement for Timed-Event Sequential Data: A Comparison of Time-Based and Event-Based Algorithms

    PubMed Central

    Bakeman, Roger; Quera, Vicenç; Gnisci, Augusto

    2009-01-01

    Observer agreement is often regarded as the sine qua non of observational research. Cohen’s kappa is a widely-used index and is appropriate when discrete entities, such as a turn-of-talk or a demarcated time-interval, are presented to pairs of observers to code. Kappa-like statistics and agreement matrixes are also used for the timed-event sequential data produced when observers first segment and then code events detected in the stream of behavior, noting onset and offset times. Such kappas are of two kinds, time-based and event-based. Available for download is a computer program (OASTES, Observer Agreement for Simulated Timed Event Sequences) that simulates the coding of observers of a stated accuracy, and then computes agreement statistics for two time-based kappas (with and without tolerance) and three event-based kappas (one implemented in The Observer, one in INTERACT, and one in GSEQ). Based on simulation results presented here, and due to the somewhat different information provide by each, reporting of both a time-based and an event-based kappa is recommended. PMID:19182133

  17. Breaking the millisecond barrier on SpiNNaker: implementing asynchronous event-based plastic models with microsecond resolution.

    PubMed

    Lagorce, Xavier; Stromatias, Evangelos; Galluppi, Francesco; Plana, Luis A; Liu, Shih-Chii; Furber, Steve B; Benosman, Ryad B

    2015-01-01

    Spike-based neuromorphic sensors such as retinas and cochleas, change the way in which the world is sampled. Instead of producing data sampled at a constant rate, these sensors output spikes that are asynchronous and event driven. The event-based nature of neuromorphic sensors implies a complete paradigm shift in current perception algorithms toward those that emphasize the importance of precise timing. The spikes produced by these sensors usually have a time resolution in the order of microseconds. This high temporal resolution is a crucial factor in learning tasks. It is also widely used in the field of biological neural networks. Sound localization for instance relies on detecting time lags between the two ears which, in the barn owl, reaches a temporal resolution of 5 μs. Current available neuromorphic computation platforms such as SpiNNaker often limit their users to a time resolution in the order of milliseconds that is not compatible with the asynchronous outputs of neuromorphic sensors. To overcome these limitations and allow for the exploration of new types of neuromorphic computing architectures, we introduce a novel software framework on the SpiNNaker platform. This framework allows for simulations of spiking networks and plasticity mechanisms using a completely asynchronous and event-based scheme running with a microsecond time resolution. Results on two example networks using this new implementation are presented. PMID:26106288

  18. Breaking the millisecond barrier on SpiNNaker: implementing asynchronous event-based plastic models with microsecond resolution

    PubMed Central

    Lagorce, Xavier; Stromatias, Evangelos; Galluppi, Francesco; Plana, Luis A.; Liu, Shih-Chii; Furber, Steve B.; Benosman, Ryad B.

    2015-01-01

    Spike-based neuromorphic sensors such as retinas and cochleas, change the way in which the world is sampled. Instead of producing data sampled at a constant rate, these sensors output spikes that are asynchronous and event driven. The event-based nature of neuromorphic sensors implies a complete paradigm shift in current perception algorithms toward those that emphasize the importance of precise timing. The spikes produced by these sensors usually have a time resolution in the order of microseconds. This high temporal resolution is a crucial factor in learning tasks. It is also widely used in the field of biological neural networks. Sound localization for instance relies on detecting time lags between the two ears which, in the barn owl, reaches a temporal resolution of 5 μs. Current available neuromorphic computation platforms such as SpiNNaker often limit their users to a time resolution in the order of milliseconds that is not compatible with the asynchronous outputs of neuromorphic sensors. To overcome these limitations and allow for the exploration of new types of neuromorphic computing architectures, we introduce a novel software framework on the SpiNNaker platform. This framework allows for simulations of spiking networks and plasticity mechanisms using a completely asynchronous and event-based scheme running with a microsecond time resolution. Results on two example networks using this new implementation are presented. PMID:26106288

  19. Event-based Prospective Memory and Everyday Forgetting in Healthy Older Adults and Individuals with Mild Cognitive Impairment

    PubMed Central

    Tam, Joyce W.; Schmitter-Edgecombe, Maureen

    2013-01-01

    An event-based non-focal task was used to evaluate prospective memory (PM), and the relationship between PM, neuropsychological testing data and everyday forgetting. Twenty-four participants with mild cognitive impairment (MCI) and 24 age and education matched cognitively healthy adults responded to a non-focal PM cue, while completing an ongoing working memory task. Neuropsychological testing data and self- and informant-report of frequency of forgetting were also gathered. Compared to healthy adults, the MCI participants exhibited significantly poorer prospective remembering and ongoing task performance, despite similar self-reported effort directed to the PM task. Both self- and informant-report indicated that the MCI group was experiencing a higher frequency of everyday forgetting than the healthy adult group. Self-report of everyday forgetting was correlated with PM task performance for the healthy adults, but not the MCI participants. For the healthy adults, correlational analyses also showed significant relationships between PM accuracy and tests of memory and executive functioning, suggesting that both spontaneous retrieval processes and effortful, strategic monitoring may be important in supporting prospective remembering for this non-focal PM task. The stronger relationships between PM accuracy and memory and language tests for the MCI group suggests that their poorer event-based prospective remembering might be linked to impaired spontaneous retrieval processes, which are thought to be supported by medial temporal structures. PMID:23419059

  20. Event-based criteria in GT-STAF information indices: theory, exploratory diversity analysis and QSPR applications.

    PubMed

    Barigye, S J; Marrero-Ponce, Y; Martínez López, Y; Martínez Santiago, O; Torrens, F; García Domenech, R; Galvez, J

    2013-01-01

    Versatile event-based approaches for the definition of novel information theory-based indices (IFIs) are presented. An event in this context is the criterion followed in the "discovery" of molecular substructures, which in turn serve as basis for the construction of the generalized incidence and relations frequency matrices, Q and F, respectively. From the resultant F, Shannon's, mutual, conditional and joint entropy-based IFIs are computed. In previous reports, an event named connected subgraphs was presented. The present study is an extension of this notion, in which we introduce other events, namely: terminal paths, vertex path incidence, quantum subgraphs, walks of length k, Sach's subgraphs, MACCs, E-state and substructure fingerprints and, finally, Ghose and Crippen atom-types for hydrophobicity and refractivity. Moreover, we define magnitude-based IFIs, introducing the use of the magnitude criterion in the definition of mutual, conditional and joint entropy-based IFIs. We also discuss the use of information-theoretic parameters as a measure of the dissimilarity of codified structural information of molecules. Finally, a comparison of the statistics for QSPR models obtained with the proposed IFIs and DRAGON's molecular descriptors for two physicochemical properties log P and log K of 34 derivatives of 2-furylethylenes demonstrates similar to better predictive ability than the latter. PMID:23066866

  1. Deficits in cue detection underlie event-based prospective memory impairment in major depression: an eye tracking study.

    PubMed

    Chen, Siyi; Zhou, Renlai; Cui, Hong; Chen, Xinyin

    2013-10-30

    This study examined the cue detection in the non-focal event-based prospective memory (PM) of individuals with and without a major depressive disorder using behavioural and eye tracking assessments. The participants were instructed to search on each trial for a different target stimulus that could be present or absent and to make prospective responses to the cue object. PM tasks included cue only and target plus cue, whereas ongoing tasks included target only and distracter only. The results showed that a) participants with depression performed more poorly than those without depression in PM; b) participants with depression showed more fixations and longer total and average fixation durations in both ongoing and PM conditions; c) participants with depression had lower scores on accuracy in target-plus-cue trials than in cue-only trials and had a higher gaze rate of targets on hits and misses in target-plus-cue trials than did those without depression. The results indicate that the state of depression may impair top-down cognitive control function, which in turn results in particular deficits in the engagement of monitoring for PM cues. PMID:23477903

  2. Evaluation of the Health Protection Event-Based Surveillance for the London 2012 Olympic and Paralympic Games.

    PubMed

    Severi, E; Kitching, A; Crook, P

    2014-01-01

    The Health Protection Agency (HPA) (currently Public Health England) implemented the Health Protection Event-Based Surveillance (EBS) to provide additional national epidemic intelligence for the 2012 London Olympic and Paralympic Games (the Games). We describe EBS and evaluate the system attributes. EBS aimed at identifying, assessing and reporting to the HPA Olympic Coordination Centre (OCC) possible national infectious disease threats that may significantly impact the Games. EBS reported events in England from 2 July to 12 September 2012. EBS sourced events from reports from local health protection units and from screening an electronic application 'HPZone Dashboard' (DB). During this period, 147 new events were reported to EBS, mostly food-borne and vaccine-preventable diseases: 79 from regional units, 144 from DB (76 from both). EBS reported 61 events to the OCC: 21 of these were reported onwards. EBS sensitivity was 95.2%; positive predictive value was 32.8%; reports were timely (median one day; 10th percentile: 0 days - same day; 90th percentile: 3.6 days); completeness was 99.7%; stability was 100%; EBS simplicity was assessed as good; the daily time per regional or national unit dedicated to EBS was approximately 4 hours (weekdays) and 3 hours (weekends). OCC directors judged EBS as efficient, fast and responsive. EBS provided reliable, reassuring, timely, simple and stable national epidemic intelligence for the Games. PMID:24970374

  3. Infectious diseases prioritisation for event-based surveillance at the European Union level for the 2012 Olympic and Paralympic Games.

    PubMed

    Economopoulou, A; Kinross, P; Domanovic, D; Coulombier, D

    2014-01-01

    In 2012, London hosted the Olympic and Paralympic Games (the Games), with events occurring throughout the United Kingdom (UK) between 27 July and 9 September 2012. Public health surveillance was performed by the Health Protection Agency (HPA). Collaboration between the HPA and the European Centre for Disease Prevention and Control (ECDC) was established for the detection and assessment of significant infectious disease events (SIDEs) occurring outside the UK during the time of the Games. Additionally, ECDC undertook an internal prioritisation exercise to facilitate ECDC’s decisions on which SIDEs should have preferentially enhanced monitoring through epidemic intelligence activities for detection and reporting in daily surveillance in the European Union (EU). A team of ECDC experts evaluated potential public health risks to the Games, selecting and prioritising SIDEs for event-based surveillance with regard to their potential for importation to the Games, occurrence during the Games or export to the EU/European Economic Area from the Games. The team opted for a multilevel approach including comprehensive disease selection, development and use of a qualitative matrix scoring system and a Delphi method for disease prioritisation. The experts selected 71 infectious diseases to enter the prioritisation exercise of which 27 were considered as priority for epidemic intelligence activities by ECDC for the EU for the Games. PMID:24762663

  4. Assessing the impact of utilizing event based water erosion versus static average water erosion (RUSLE) in carbon turnover modeling

    NASA Astrophysics Data System (ADS)

    Wilken, Florian; Fiener, Peter

    2015-04-01

    The discrepancy between the time scales at which soil redistribution processes and SOC turnover occur is an unresolved issue in erosion related carbon turnover modeling. The use of a static average erosion rate (e.g. revised universal soil loss equation; RUSLE) ignores event dynamic processes of (i) SOC enrichment during erosion, transport and deposition, (ii) event specific C release to the atmosphere during erosion processes, and (iii) event specific depth of SOC burial,. We hypothesize that event driven SOC enrichment and SOC burial is of fundamental importance for inter-annual carbon turnover. The study was carried out in an arable watershed (3.7 ha) with no-till management located in the loess dominated Tertiary hills 40 km north of Munich, Germany. To assess the importance of event dynamic SOC redistribution processes, we implemented two different water erosion modelling approaches in the coupled erosion and turnover model SPEROS-C. The first, RUSLE-based approach as already implemented in SPEROS-C, represents long-term mean erosion, while the second is based on the high-resolution, event-based and especially sediment size class selective Multi-Class Sediment Transport model (MCST). In both cases bulk sediment delivery and in case of MCST sediment size specific sediment delivery are tested and partly calibrated against an eight year monitoring data set. First results indicate that especially SOC enrichment during erosion, transport and deposition should be included in estimates of soil redistribution processes upon watershed C balances. The modelling with MCST also indicates that interpreting SOC patterns in eroding landscapes might be also biased if the selective nature of SOC erosion and deposition is ignored.

  5. Investigating the variation and non-stationarity in precipitation extremes based on the concept of event-based extreme precipitation

    NASA Astrophysics Data System (ADS)

    She, Dunxian; Shao, Quanxi; Xia, Jun; Taylor, John A.; Zhang, Yongyong; Zhang, Liping; Zhang, Xiang; Zou, Lei

    2015-11-01

    Extreme precipitations (EP) could induce a series of social, environmental and ecological problems. Traditional EP analysis usually investigated the characteristics based on a fixed time scale and therefore ignored the continuity of EP occurrence. As a result, a comprehensive assessment on the influence and consequence of the EP occurring during consecutive time periods were largely eliminated. On the other hand, the characteristics of EP, including variables such as frequency, intensity and extreme volume, were commonly defined without sufficient consideration of the local tolerance capacity (which can be represented by a threshold level of EP) and therefore would sometimes be inappropriate. In this study, we proposed a concept of event-based extreme precipitation (EEP) by considering the continuity of EP and defined the statistical variables for the characteristics of an EEP event by taking account of local tolerance capacity. An EEP was identified as a collection of precipitation data over the consecutive time period in which all the precipitation amounts are above the pre-defined threshold, and EEP events are separated by at least one time step (e.g., day or hour) with precipitation amount below the threshold. As a case study which in fact motivated our proposal, we investigated the changes and variations of EEP with the consideration of potential non-stationarity in the Hanjiang River Basin of China (HJRB) during the time period of 1960-2013. Results showed that the concept of EEP, which could reflect the impact of continuity of EP occurrence and mirror the differences of local tolerance capacity, was more appropriate than the traditional method in the EP analysis.

  6. Comparison of Patients with Parkinson's Disease or Cerebellar Lesions in the Production of Periodic Movements Involving Event-Based or Emergent Timing

    ERIC Educational Resources Information Center

    Spencer, R.M.C.; Ivry, R.B.

    2005-01-01

    We have hypothesized a distinction between the processes required to control the timing of different classes of periodic movements. In one class, salient events mark successive cycles. For these movements, we hypothesize that the temporal goal is a requisite component of the task representation, what we refer to as event-based timing. In the other…

  7. Time-Based and Event-Based Prospective Memory in Autism Spectrum Disorder: The Roles of Executive Function and Theory of Mind, and Time-Estimation

    ERIC Educational Resources Information Center

    Williams, David; Boucher, Jill; Lind, Sophie; Jarrold, Christopher

    2013-01-01

    Prospective memory (remembering to carry out an action in the future) has been studied relatively little in ASD. We explored time-based (carry out an action at a pre-specified time) and event-based (carry out an action upon the occurrence of a pre-specified event) prospective memory, as well as possible cognitive correlates, among 21

  8. The Cognitive Processes Underlying Event-Based Prospective Memory in School-Age Children and Young Adults: A Formal Model-Based Study

    ERIC Educational Resources Information Center

    Smith, Rebekah E.; Bayen, Ute J.; Martin, Claudia

    2010-01-01

    Fifty children 7 years of age (29 girls, 21 boys), 53 children 10 years of age (29 girls, 24 boys), and 36 young adults (19 women, 17 men) performed a computerized event-based prospective memory task. All 3 groups differed significantly in prospective memory performance, with adults showing the best performance and with 7-year-olds showing the…

  9. Time-Based and Event-Based Prospective Memory in Autism Spectrum Disorder: The Roles of Executive Function and Theory of Mind, and Time-Estimation

    ERIC Educational Resources Information Center

    Williams, David; Boucher, Jill; Lind, Sophie; Jarrold, Christopher

    2013-01-01

    Prospective memory (remembering to carry out an action in the future) has been studied relatively little in ASD. We explored time-based (carry out an action at a pre-specified time) and event-based (carry out an action upon the occurrence of a pre-specified event) prospective memory, as well as possible cognitive correlates, among 21…

  10. Flood modelling with a distributed event-based parsimonious rainfall-runoff model: case of the karstic Lez river catchment

    NASA Astrophysics Data System (ADS)

    Coustau, M.; Bouvier, C.; Borrell-Estupina, V.; Jourde, H.

    2012-04-01

    Rainfall-runoff models are crucial tools for the statistical prediction of flash floods and real-time forecasting. This paper focuses on a karstic basin in the South of France and proposes a distributed parsimonious event-based rainfall-runoff model, coherent with the poor knowledge of both evaporative and underground fluxes. The model combines a SCS runoff model and a Lag and Route routing model for each cell of a regular grid mesh. The efficiency of the model is discussed not only to satisfactorily simulate floods but also to get powerful relationships between the initial condition of the model and various predictors of the initial wetness state of the basin, such as the base flow, the Hu2 index from the Meteo-France SIM model and the piezometric levels of the aquifer. The advantage of using meteorological radar rainfall in flood modelling is also assessed. Model calibration proved to be satisfactory by using an hourly time step with Nash criterion values, ranging between 0.66 and 0.94 for eighteen of the twenty-one selected events. The radar rainfall inputs significantly improved the simulations or the assessment of the initial condition of the model for 5 events at the beginning of autumn, mostly in September-October (mean improvement of Nash is 0.09; correction in the initial condition ranges from -205 to 124 mm), but were less efficient for the events at the end of autumn. In this period, the weak vertical extension of the precipitation system and the low altitude of the 0 C isotherm could affect the efficiency of radar measurements due to the distance between the basin and the radar (~60 km). The model initial condition S is correlated with the three tested predictors (R2 > 0.6). The interpretation of the model suggests that groundwater does not affect the first peaks of the flood, but can strongly impact subsequent peaks in the case of a multi-storm event. Because this kind of model is based on a limited amount of readily available data, it should be suitable for operational applications.

  11. The Cognitive Processes Underlying Event-Based Prospective Memory In School Age Children and Young Adults: A Formal Model-Based Study

    PubMed Central

    Smith, Rebekah E.; Bayen, Ute Johanna; Martin, Claudia

    2010-01-01

    Fifty 7-year-olds (29 female), 53 10-year-olds (29 female), and 36 young adults (19 female), performed a computerized event-based prospective memory task. All three groups differed significantly in prospective memory performance with adults showing the best performance and 7-year-olds the poorest performance. We used a formal multinomial process tree model of event-based prospective memory to decompose age differences in cognitive processes that jointly contribute to prospective memory performance. The formal modeling results demonstrated that adults differed significantly from the 7-year-olds and 10-year-olds on both the prospective component and the retrospective component of the task. The 7-year-olds and 10-year-olds differed only in the ability to recognize prospective memory target events. The prospective memory task imposed a cost to ongoing activities in all three age groups. PMID:20053020

  12. Time-based and event-based prospective memory in autism spectrum disorder: the roles of executive function and theory of mind, and time-estimation.

    PubMed

    Williams, David; Boucher, Jill; Lind, Sophie; Jarrold, Christopher

    2013-07-01

    Prospective memory (remembering to carry out an action in the future) has been studied relatively little in ASD. We explored time-based (carry out an action at a pre-specified time) and event-based (carry out an action upon the occurrence of a pre-specified event) prospective memory, as well as possible cognitive correlates, among 21 intellectually high-functioning children with ASD, and 21 age- and IQ-matched neurotypical comparison children. We found impaired time-based, but undiminished event-based, prospective memory among children with ASD. In the ASD group, time-based prospective memory performance was associated significantly with diminished theory of mind, but not with diminished cognitive flexibility. There was no evidence that time-estimation ability contributed to time-based prospective memory impairment in ASD. PMID:23179340

  13. Diminished Time-Based, but Undiminished Event-Based, Prospective Memory Among Intellectually High-Functioning Adults With Autism Spectrum Disorder: Relation to Working Memory Ability

    PubMed Central

    2013-01-01

    Objective: Prospective memory (PM) is the ability to remember to carry out an intended action. Working memory is the ability to store information in mind while processing potentially distracting information. The few previous studies of PM in autism spectrum disorder (ASD) have yielded inconsistent findings. Studies of working memory ability in ASD have suggested a selective impairment of “visual working memory.” However, it remains unclear whether any such impairment is the result of diminished (domain-specific; visual/verbal) storage capacity or diminished (domain-general) processing capacity. We aim to clarify these issues and explore the relation between PM and working memory in ASD. Method: Seventeen adults with ASD and 17 age- and IQ-matched comparison participants completed experimental measures of both event-based (perform action x when event y occurs) and time-based (perform action a at time b) PM, plus a self-report measure of PM skills. Participants also completed a working memory test battery. Results: Participants with ASD self-reported diminished PM skill, and showed diminished performance on the time-based, but not event-based, PM task. On the working memory test battery, visual but not verbal storage capacity was diminished among participants with ASD, as was processing ability. Whereas visual storage was associated with event-based PM task performance among comparison participants, verbal storage was associated among ASD participants. Conclusions: ASD appears to involve a selective deficit in time-based PM and a selective difficulty with aspects of working memory that depend on the storage of visual information. However, event-based PM may be achieved through compensatory strategies in ASD. PMID:24128041

  14. Event-Based Runoff Across Changing Land Covers in the Panama Canal Watershed: A Synthesis of Hydrophysical Measurements and Hydrochemical Tracers Using Hydrograph Separation

    NASA Astrophysics Data System (ADS)

    Litt, G.; Gardner, C.; Ogden, F. L.; Lyons, W. B.

    2014-12-01

    Tropical hydrology is understudied relative to its temperate counterparts and thus presents challenges for understanding catchment runoff behavior undergoing land use change. Combining hydrometric and hydrochemical observations can shed light on potential differences in runoff processes under changing land covers. We compare event-based dual member hydrograph separations across humid tropical lowland forest (142 ha), mixed land use (176 ha) and pasture (36 ha) catchments following two years of monitoring during the seasonal dry to wet season transition. Stable water isotope and electrical conductivity tracer event water fraction estimations agree well during small runoff events, but exhibit different results during a large runoff event with a greater runoff coefficient. Geochemical tracers exhibit event water fraction maximums during hydrograph recessions and a seasonal transition in runoff behavior among all land uses. From these results we identify potential runoff mechanisms in these steep humid tropical catchments under varying land uses.

  15. Simulation of event-based and long-term spatial redistribution of Chernobyl-derived radiocaesium within catchments using geographical information system embedded models

    NASA Astrophysics Data System (ADS)

    van der Perk, Marcel; Slávik, Ondrej

    2003-04-01

    The Chernobyl accident contaminated vast areas of Europe with radiocaesium (137Cs) in 1986. To evaluate long-term and event-based redistribution of Chernobyl-derived 137Cs at the catchment scale, two geographical information system embedded models have been developed. The first model simulates 137Cs redistribution using a monthly time step based on a long-term soil erosion model. The second model simulates lateral radiocaesium transport at the event scale based on the existing Limburg soil erosion model. This model accounts for surface runoff, soil erosion and deposition, and radiocaesium exchange between the topsoil layer, runoff water, and suspended sediment. Both models have been tested and applied to the Mochovce catchment, western Slovakia. The spatial distribution of 137Cs activity in soil simulated by the long-term model was used as input for the event-based model to assess the changes in 137Cs transport during rainfall events between 1986 and 2002. Soil erosion events in the first months after initial fallout input before ploughing caused a considerable decline in the 137Cs soil inventories, which were estimated at 8·9% of the total initial inventory. The majority of 137Cs transport during rainfall events occurs in particulate form. Both the absolute amounts of particulate 137Cs transport and the fraction of particulate 137Cs transport were shown to be positively related to suspended sediment transport. Between 1986 and 2002, dissolved 137Cs transport has declined by a factor of about 26, which can be largely attributed to the increased sorption to sediment particles. Particulate 137Cs transport has declined by a factor of about two, which can be largely attributed to the decrease in soil 137Cs. The 137Cs inventories in soil have decreased by a factor between three and four at the steep hillslopes, but have remained at about the same level as the initial fallout input at the valley bottoms.

  16. Issues for Simulation of Galactic Cosmic Ray Exposures for Radiobiological Research at Ground-Based Accelerators.

    PubMed

    Kim, Myung-Hee Y; Rusek, Adam; Cucinotta, Francis A

    2015-01-01

    For radiobiology research on the health risks of galactic cosmic rays (GCR) ground-based accelerators have been used with mono-energetic beams of single high charge, Z and energy, E (HZE) particles. In this paper, we consider the pros and cons of a GCR reference field at a particle accelerator. At the NASA Space Radiation Laboratory (NSRL), we have proposed a GCR simulator, which implements a new rapid switching mode and higher energy beam extraction to 1.5 GeV/u, in order to integrate multiple ions into a single simulation within hours or longer for chronic exposures. After considering the GCR environment and energy limitations of NSRL, we performed extensive simulation studies using the stochastic transport code, GERMcode (GCR Event Risk Model) to define a GCR reference field using 9 HZE particle beam-energy combinations each with a unique absorber thickness to provide fragmentation and 10 or more energies of proton and (4)He beams. The reference field is shown to well represent the charge dependence of GCR dose in several energy bins behind shielding compared to a simulated GCR environment. However, a more significant challenge for space radiobiology research is to consider chronic GCR exposure of up to 3 years in relation to simulations with animal models of human risks. We discuss issues in approaches to map important biological time scales in experimental models using ground-based simulation, with extended exposure of up to a few weeks using chronic or fractionation exposures. A kinetics model of HZE particle hit probabilities suggests that experimental simulations of several weeks will be needed to avoid high fluence rate artifacts, which places limitations on the experiments to be performed. Ultimately risk estimates are limited by theoretical understanding, and focus on improving knowledge of mechanisms and development of experimental models to improve this understanding should remain the highest priority for space radiobiology research. PMID:26090339

  17. Issues for Simulation of Galactic Cosmic Ray Exposures for Radiobiological Research at Ground-Based Accelerators

    PubMed Central

    Kim, Myung-Hee Y.; Rusek, Adam; Cucinotta, Francis A.

    2015-01-01

    For radiobiology research on the health risks of galactic cosmic rays (GCR) ground-based accelerators have been used with mono-energetic beams of single high charge, Z and energy, E (HZE) particles. In this paper, we consider the pros and cons of a GCR reference field at a particle accelerator. At the NASA Space Radiation Laboratory (NSRL), we have proposed a GCR simulator, which implements a new rapid switching mode and higher energy beam extraction to 1.5 GeV/u, in order to integrate multiple ions into a single simulation within hours or longer for chronic exposures. After considering the GCR environment and energy limitations of NSRL, we performed extensive simulation studies using the stochastic transport code, GERMcode (GCR Event Risk Model) to define a GCR reference field using 9 HZE particle beam–energy combinations each with a unique absorber thickness to provide fragmentation and 10 or more energies of proton and 4He beams. The reference field is shown to well represent the charge dependence of GCR dose in several energy bins behind shielding compared to a simulated GCR environment. However, a more significant challenge for space radiobiology research is to consider chronic GCR exposure of up to 3 years in relation to simulations with animal models of human risks. We discuss issues in approaches to map important biological time scales in experimental models using ground-based simulation, with extended exposure of up to a few weeks using chronic or fractionation exposures. A kinetics model of HZE particle hit probabilities suggests that experimental simulations of several weeks will be needed to avoid high fluence rate artifacts, which places limitations on the experiments to be performed. Ultimately risk estimates are limited by theoretical understanding, and focus on improving knowledge of mechanisms and development of experimental models to improve this understanding should remain the highest priority for space radiobiology research. PMID:26090339

  18. Preserved Intention Maintenance and Impaired Execution of Prospective Memory Responses in Schizophrenia: Evidence from an Event-based Prospective Memory Study

    PubMed Central

    Demeter, Gyula; Szendi, István; Domján, Nóra; Juhász, Marianna; Greminger, Nóra; Szőllősi, Ágnes; Racsmány, Mihály

    2016-01-01

    Executive system dysfunction and impaired prospective memory (PM) are widely documented in schizophrenia. However, it is not yet clarified which components of PM function are impaired in this disorder. Two plausible target components are the maintenance of delayed intentions and the execution of PM responses. Furthermore, it is debated whether the impaired performance on frequently used executive tasks is associated with deficit in PM functions. The aim of our study was twofold. First, we aimed to investigate the specific processes involved in event-based PM function, mainly focusing on difference between maintenance of intention and execution of PM responses. Second, we aimed to unfold the possible connections between executive functions, clinical symptoms, and PM performance. An event-based PM paradigm was applied with three main conditions: baseline (with no expectation of PM stimuli, and without PM stimuli), expectation condition (participants were told that PM stimuli might occur, though none actually did), and execution condition (participants were told that PM stimuli might occur, and PM stimuli did occur). This procedure allowed us to separately investigate performances associated with intention maintenance and execution of PM responses. We assessed working memory and set-shifting executive functions by memory span tasks and by the Wisconsin Card Sorting Test (WCST), respectively. Twenty patients diagnosed with schizophrenia and 20 healthy control subjects (matched according to age and education) took part in the study. It was hypothesized that patients would manifest different levels of performance in the expectation and execution conditions of the PM task. Our results confirmed that the difference between baseline performance and performance in the execution condition (execution cost) was significantly larger for participants diagnosed with schizophrenia in comparison with matched healthy control group. However, this difference was not observed in the expectation condition. The PM performance in the execution condition was correlated with impaired executive functions in schizophrenia. Specifically, the size of execution cost positively correlated with percent of perseverative errors committed on WCST by the patient group. Our results suggest that maintenance of delayed intentions is unimpaired in schizophrenia, whereas the impairment in execution of PM responses is associated with set-shifting deficit. PMID:27199827

  19. Task Importance Affects Event-based Prospective Memory Performance in Adults with HIV-Associated Neurocognitive Disorders and HIV-infected Young Adults with Problematic Substance Use

    PubMed Central

    Woods, Steven Paul; Doyle, Katie L.; Morgan, Erin E.; Naar-King, Sylvie; Outlaw, Angulique Y.; Nichols, Sharon L.; Loft, Shayne

    2014-01-01

    Objective Two experiments were conducted to examine the effects of task importance on event-based prospective memory (PM) in separate samples of adults with HIV-associated Neurocognitive Disorders (HAND) and HIV-infected young adults with Substance Use Disorders (SUD). Method All participants completed three conditions of an ongoing lexical decision task: 1) without PM task requirements; 2) with PM task requirements that emphasized the importance of the ongoing task; and 3) with PM task requirements that emphasized the importance of the PM task. Results In both experiments, all HIV+ groups showed the expected increase in response costs to the ongoing task when the PM task’s importance was emphasized. In Experiment 1, individuals with HAND showed significantly lower PM accuracy as compared to HIV+ subjects without HAND when the importance of the ongoing task was emphasized, but improved significantly and no longer differed from HIV+ subjects without HAND when the PM task was emphasized. A similar pattern of findings emerged in Experiment 2, whereby HIV+ young adults with SUD (especially cannabis) showed significant improvements in PM accuracy when the PM task was emphasized. Conclusions Findings suggest that both HAND and SUD may increase the amount of cognitive attentional resources that need to be allocated to support PM performance in persons living with HIV infection. PMID:24834469

  20. Sexual frequency and planning among at-risk men who have sex with men (MSM) in the US: implications for event-based intermittent pre-exposure prophylaxis (iPrEP)

    PubMed Central

    Volk, Jonathan E.; Liu, Albert; Vittinghoff, Eric; Irvin, Risha; Kroboth, Elizabeth; Krakower, Douglas; Mimiaga, Matthew J.; Mayer, Kenneth H.; Sullivan, Patrick S.; Buchbinder, Susan

    2012-01-01

    Intermittent dosing of pre-exposure prophylaxis (iPrEP) has potential to decrease costs, improve adherence, and minimize toxicity. Practical event-based dosing of iPrEP requires men who have sex with men (MSM) to be sexually active on fewer than 3 days each week and plan for sexual activity. MSM who may be most suitable for event-based dosing were older, more educated, more frequently used sexual networking websites, and more often reported that their last sexual encounter was not with a committed partner. A substantial proportion of these MSM endorse high-risk sexual activity, and event-based iPrEP may best target this population. PMID:22592590

  1. Modeller subjectivity and calibration impacts on hydrological model applications: an event-based comparison for a road-adjacent catchment in south-east Norway.

    PubMed

    Kalantari, Zahra; Lyon, Steve W; Jansson, Per-Erik; Stolte, Jannes; French, Helen K; Folkeson, Lennart; Sassner, Mona

    2015-01-01

    Identifying a 'best' performing hydrologic model in a practical sense is difficult due to the potential influences of modeller subjectivity on, for example, calibration procedure and parameter selection. This is especially true for model applications at the event scale where the prevailing catchment conditions can have a strong impact on apparent model performance and suitability. In this study, two lumped models (CoupModel and HBV) and two physically-based distributed models (LISEM and MIKE SHE) were applied to a small catchment upstream of a road in south-eastern Norway. All models were calibrated to a single event representing typical winter conditions in the region and then applied to various other winter events to investigate the potential impact of calibration period and methodology on model performance. Peak flow and event-based hydrographs were simulated differently by all models leading to differences in apparent model performance under this application. In this case-study, the lumped models appeared to be better suited for hydrological events that differed from the calibration event (i.e., events when runoff was generated from rain on non-frozen soils rather than from rain and snowmelt on frozen soil) while the more physical-based approaches appeared better suited during snowmelt and frozen soil conditions more consistent with the event-specific calibration. This was due to the combination of variations in subsurface conditions over the eight events considered, the subsequent ability of the models to represent the impact of the conditions (particularly when subsurface conditions varied greatly from the calibration event), and the different approaches adopted to calibrate the models. These results indicate that hydrologic models may not only need to be selected on a case-by-case basis but also have their performance evaluated on an application-by-application basis since how a model is applied can be equally important as inherent model structure. PMID:25262294

  2. Flood-event based metal distribution patterns in water as approach for source apportionment of pollution on catchment scale: Examples from the River Elbe

    NASA Astrophysics Data System (ADS)

    Baborowski, Martina; Einax, Jürgen W.

    2016-04-01

    With the implementation of European Water Frame Work Directive (EU-WFD), the pollution sources in the River Elbe were assessed by the River Basin Community Elbe (RBC Elbe). Contaminated old sediments played the most significant role for inorganic and organic pollution. In terms of further improvement of the water quality in the river system, a prioritization of the known pollution sources is necessary, with respect to the expected effect in the case of their remediation. This requires information on mobility of contaminated sediments. To create a tool that allows the assessment of pollution trends in the catchment area, event based flood investigations were carried out at a sampling site in the Middle Elbe. The investigations were based on a comparable, discharge related sampling strategy. Four campaigns were performed between 1995 and 2006. The majority of the investigated 16 elements (>80%) studied more intensively in 2006 reached its maximum concentration during the first five days of the event. Only the concentrations of B, Cl-, and U declined with increasing discharge during the flood. The aim of the study was to verify that each flood event is characterized by an internal structure of the water quality. This structure is formed by the appearance of maximum values of water quality parameters at different times during the event. It could be detected by descriptive and multivariate statistical methods. As a result, internal structure of the water quality during the flood was influenced primarily by the source of the metals in the catchment area and its distance from the sampling point. The transport of metals in dissolved, colloidal or particulate form and changes of their ratios during the flood were however, not decisive for the formation of the structure. Our results show that the comparison of the structures obtained from events in different years is indicative of the pollution trend in the catchment area. Exemplarily the trend of the metal pollution in the River Elbe will be discussed.

  3. Modeling rates of bank erosion in sinuous tidal channel derived from event-based terrestrial lidar surveys in the Mont Saint Michel Bay

    NASA Astrophysics Data System (ADS)

    Leroux, J.; Lague, D.

    2012-12-01

    The Mont-Saint-Michel (MSM) bay is characterized by a semi-diurnal regime with a tidal range of 14 meter. Understanding river bank migration of tidal channels in such mega tidal salt marshes requires a precise quantification of the relative contribution of frequent and infrequent bank erosion events to the longer term dynamics. We use terrestrial lidar scanner (TLS) which overcomes the limitations of traditional bank measurement approaches (e.g. aerial photography, GPS measurements) with high resolution and high precision topographic data. We use 30 TLS measurements and traditional data sources to quantify the annual and daily dynamics of bank erosion for a sinuous salt marsh channel near the island of the MSM. We present the results of a 2 years study that begun in September 2010. We compare annual bank retreat with daily surveys focused on spring tides in order to calculate "event-based" volume of bank erosion. For active steep banks, the volume of sediment eroded is computed between 2 set of point cloud that are classified by the CANUPO algorithm to remove vegetation (Brodu and Lague, 2012). A new algorithm allows a direct comparison of point clouds in 3D based on surface normal computation and measurement of mean surface change along the normal direction. On a 5 centimeter resolution grid, the changes between 2 banks point cloud is computed and used to calculate volume of eroded bank. Measured rates of bank retreat varied between no detectable change to 2 m/tide, which correspond roughly to 100 cubic meters/tide. We also document a non-homothetic pattern of bank erosion during spring tides : erosion is focused in narrow zones of the meander and shifts spatially at daily timescales. To relate bank erosion to hydraulic characteristics of the channel, an ADCP was used to measure flow velocity during tides. The measurements highlights two main points that only occurs when tides overcomes the salt marsh: (i) the ebb flow is stronger than flood flow with velocities up to 2.2 m/s and (ii) the maximum ebb velocity (MEV) increase linearly with the maximum tide height. The dominant role of the ebb was also noted during field observations : during the ebb, the flow is focused on a narrow zone of the bank due to rapid bathymetric modifications at daily timescales. This could explain the non-homothetic behavior of bank erosion. The daily volume of eroded bank is only significant when the tide overcome the salt marsh which occurs 10 % of time. From the linear relationship between tide height and MEV, we can relate bank erosion to flow velocity. We show that the eroded volume increases exponentially with the MEV. This new physical model of bank erosion is applied on daily tides records. From Sept 2010 to June 2012, the model succeeds to estimate the volume of bank eroded. However, the model fails to reproduce the dynamics before Sept 2010, which can be explained by a significant change in channel curvature and morphology. The study shows that the combination of TLS and hydrosedimentary measurements can be used to construct 'field' models of tidal channel dynamics. Our data highlights a strong non-linearity between bank erosion, tidal amplitude and ebb flow velocity that results in spring tide events representing 95.7 % of the total erosion for a duration of 10 % of time.

  4. GCR-Induced Photon Luminescence of the Moon

    NASA Technical Reports Server (NTRS)

    Lee, K. T.; Wilson, T. L.

    2008-01-01

    It is shown that the Moon has a ubiquitous photon luminescence induced by Galactic cosmic-rays (GCRs), using the Monte Carlo particle-physics program FLUKA. Both the fluence and the flux of the radiation can be determined by this method, but only the fluence will be presented here. This is in addition to thermal radiation emitted due to the Moon s internal temperature and radioactivity. This study is a follow-up to an earlier discussion [1] that addressed several misconceptions regarding Moonshine in the Earth-Moon system (Figure 1) and predicted this effect. There also exists a related x-ray fluorescence induced by solar energetic particles (SEPs, <350 MeV) and solar photons at lower x-ray energies, although this latter fluorescence was studied on Apollo 15 and 16 [2- 5], Lunar Prospector [6], and even EGRET [7].

  5. Production of neutrons from interactions of GCR-like particles

    NASA Technical Reports Server (NTRS)

    Heilbronn, L.; Frankel, K.; Holabird, K.; Zeitlin, C.; McMahan, M. A.; Rathbun, W.; Cronqvist, M.; Gong, W.; Madey, R.; Htun, M.; Elaasar, M.; Anderson, B. D.; Baldwin, A. R.; Jiang, J.; Keane, D.; Scott, A.; Shao, Y.; Watson, J. W.; Zhang, W. M.; Galonsky, A.; Ronningen, R.; Zecher, P.; Kruse, J.; Wang, J.; Miller, J. (Principal Investigator)

    1998-01-01

    In order to help assess the risk to astronauts due to the long-term exposure to the natural radiation environment in space, an understanding of how the primary radiation field is changed when passing through shielding and tissue materials must be obtained. One important aspect of the change in the primary radiation field after passing through shielding materials is the production of secondary particles from the breakup of the primary. Neutrons are an important component of the secondary particle field due to their relatively high biological weighting factors, and due to their relative abundance, especially behind thick shielding scenarios. Because of the complexity of the problem, the estimation of the risk from exposure to the secondary neutron field must be handled using calculational techniques. However, those calculations will need an extensive set of neutron cross section and thicktarget neutron yield data in order to make an accurate assessment of the risk. In this paper we briefly survey the existing neutron-production data sets that are applicable to the space radiation transport problem, and we point out how neutron production from protons is different than neutron production from heavy ions. We also make comparisons of one the heavy-ion data sets with Boltzmann-Uehling-Uhlenbeck (BUU) calculations.

  6. Event-based total suspended sediment particle size distribution model

    NASA Astrophysics Data System (ADS)

    Thompson, Jennifer; Sattar, Ahmed M. A.; Gharabaghi, Bahram; Warner, Richard C.

    2016-05-01

    One of the most challenging modelling tasks in hydrology is prediction of the total suspended sediment particle size distribution (TSS-PSD) in stormwater runoff generated from exposed soil surfaces at active construction sites and surface mining operations. The main objective of this study is to employ gene expression programming (GEP) and artificial neural networks (ANN) to develop a new model with the ability to more accurately predict the TSS-PSD by taking advantage of both event-specific and site-specific factors in the model. To compile the data for this study, laboratory scale experiments using rainfall simulators were conducted on fourteen different soils to obtain TSS-PSD. This data is supplemented with field data from three construction sites in Ontario over a period of two years to capture the effect of transport and deposition within the site. The combined data sets provide a wide range of key overlooked site-specific and storm event-specific factors. Both parent soil and TSS-PSD in runoff are quantified by fitting each to a lognormal distribution. Compared to existing regression models, the developed model more accurately predicted the TSS-PSD using a more comprehensive list of key model input parameters. Employment of the new model will increase the efficiency of deployment of required best management practices, designed based on TSS-PSD, to minimize potential adverse effects of construction site runoff on aquatic life in the receiving watercourses.

  7. Poisson-event-based analysis of cell proliferation.

    PubMed

    Summers, Huw D; Wills, John W; Brown, M Rowan; Rees, Paul

    2015-05-01

    A protocol for the assessment of cell proliferation dynamics is presented. This is based on the measurement of cell division events and their subsequent analysis using Poisson probability statistics. Detailed analysis of proliferation dynamics in heterogeneous populations requires single cell resolution within a time series analysis and so is technically demanding to implement. Here, we show that by focusing on the events during which cells undergo division rather than directly on the cells themselves a simplified image acquisition and analysis protocol can be followed, which maintains single cell resolution and reports on the key metrics of cell proliferation. The technique is demonstrated using a microscope with 1.3 μm spatial resolution to track mitotic events within A549 and BEAS-2B cell lines, over a period of up to 48 h. Automated image processing of the bright field images using standard algorithms within the ImageJ software toolkit yielded 87% accurate recording of the manually identified, temporal, and spatial positions of the mitotic event series. Analysis of the statistics of the interevent times (i.e., times between observed mitoses in a field of view) showed that cell division conformed to a nonhomogeneous Poisson process in which the rate of occurrence of mitotic events, λ exponentially increased over time and provided values of the mean inter mitotic time of 21.1 ± 1.2 hours for the A549 cells and 25.0 ± 1.1 h for the BEAS-2B cells. Comparison of the mitotic event series for the BEAS-2B cell line to that predicted by random Poisson statistics indicated that temporal synchronisation of the cell division process was occurring within 70% of the population and that this could be increased to 85% through serum starvation of the cell culture. PMID:25572722

  8. An event-based hydrologic simulation model for bioretention systems.

    PubMed

    Roy-Poirier, A; Filion, Y; Champagne, P

    2015-01-01

    Bioretention systems are designed to treat stormwater and provide attenuated drainage between storms. Bioretention has shown great potential at reducing the volume and improving the quality of stormwater. This study introduces the bioretention hydrologic model (BHM), a one-dimensional model that simulates the hydrologic response of a bioretention system over the duration of a storm event. BHM is based on the RECARGA model, but has been adapted for improved accuracy and integration of pollutant transport models. BHM contains four completely-mixed layers and accounts for evapotranspiration, overflow, exfiltration to native soils and underdrain discharge. Model results were evaluated against field data collected over 10 storm events. Simulated flows were particularly sensitive to antecedent water content and drainage parameters of bioretention soils, which were calibrated through an optimisation algorithm. Temporal disparity was observed between simulated and measured flows, which was attributed to preferential flow paths formed within the soil matrix of the field system. Modelling results suggest that soil water storage is the most important short-term hydrologic process in bioretention, with exfiltration having the potential to be significant in native soils with sufficient permeability. PMID:26524443

  9. An event-based architecture for solving constraint satisfaction problems.

    PubMed

    Mostafa, Hesham; Müller, Lorenz K; Indiveri, Giacomo

    2015-01-01

    Constraint satisfaction problems are ubiquitous in many domains. They are typically solved using conventional digital computing architectures that do not reflect the distributed nature of many of these problems, and are thus ill-suited for solving them. Here we present a parallel analogue/digital hardware architecture specifically designed to solve such problems. We cast constraint satisfaction problems as networks of stereotyped nodes that communicate using digital pulses, or events. Each node contains an oscillator implemented using analogue circuits. The non-repeating phase relations among the oscillators drive the exploration of the solution space. We show that this hardware architecture can yield state-of-the-art performance on random SAT problems under reasonable assumptions on the implementation. We present measurements from a prototype electronic chip to demonstrate that a physical implementation of the proposed architecture is robust to practical non-idealities and to validate the theory proposed. PMID:26642827

  10. Address-event-based platform for bioinspired spiking systems

    NASA Astrophysics Data System (ADS)

    Jiménez-Fernández, A.; Luján, C. D.; Linares-Barranco, A.; Gómez-Rodríguez, F.; Rivas, M.; Jiménez, G.; Civit, A.

    2007-05-01

    Address Event Representation (AER) is an emergent neuromorphic interchip communication protocol that allows a real-time virtual massive connectivity between huge number neurons, located on different chips. By exploiting high speed digital communication circuits (with nano-seconds timings), synaptic neural connections can be time multiplexed, while neural activity signals (with mili-seconds timings) are sampled at low frequencies. Also, neurons generate "events" according to their activity levels. More active neurons generate more events per unit time, and access the interchip communication channel more frequently, while neurons with low activity consume less communication bandwidth. When building multi-chip muti-layered AER systems, it is absolutely necessary to have a computer interface that allows (a) reading AER interchip traffic into the computer and visualizing it on the screen, and (b) converting conventional frame-based video stream in the computer into AER and injecting it at some point of the AER structure. This is necessary for test and debugging of complex AER systems. In the other hand, the use of a commercial personal computer implies to depend on software tools and operating systems that can make the system slower and un-robust. This paper addresses the problem of communicating several AER based chips to compose a powerful processing system. The problem was discussed in the Neuromorphic Engineering Workshop of 2006. The platform is based basically on an embedded computer, a powerful FPGA and serial links, to make the system faster and be stand alone (independent from a PC). A new platform is presented that allow to connect up to eight AER based chips to a Spartan 3 4000 FPGA. The FPGA is responsible of the network communication based in Address-Event and, at the same time, to map and transform the address space of the traffic to implement a pre-processing. A MMU microprocessor (Intel XScale 400MHz Gumstix Connex computer) is also connected to the FPGA to allow the platform to implement eventbased algorithms to interact to the AER system, like control algorithms, network connectivity, USB support, etc. The LVDS transceiver allows a bandwidth of up to 1.32 Gbps, around ~66 Mega events per second (Mevps).

  11. Event-based text mining for biology and functional genomics.

    PubMed

    Ananiadou, Sophia; Thompson, Paul; Nawaz, Raheel; McNaught, John; Kell, Douglas B

    2015-05-01

    The assessment of genome function requires a mapping between genome-derived entities and biochemical reactions, and the biomedical literature represents a rich source of information about reactions between biological components. However, the increasingly rapid growth in the volume of literature provides both a challenge and an opportunity for researchers to isolate information about reactions of interest in a timely and efficient manner. In response, recent text mining research in the biology domain has been largely focused on the identification and extraction of 'events', i.e. categorised, structured representations of relationships between biochemical entities, from the literature. Functional genomics analyses necessarily encompass events as so defined. Automatic event extraction systems facilitate the development of sophisticated semantic search applications, allowing researchers to formulate structured queries over extracted events, so as to specify the exact types of reactions to be retrieved. This article provides an overview of recent research into event extraction. We cover annotated corpora on which systems are trained, systems that achieve state-of-the-art performance and details of the community shared tasks that have been instrumental in increasing the quality, coverage and scalability of recent systems. Finally, several concrete applications of event extraction are covered, together with emerging directions of research. PMID:24907365

  12. Galactic Cosmic Ray Event-Based Risk Model (GERM) Code

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Plante, Ianik; Ponomarev, Artem L.; Kim, Myung-Hee Y.

    2013-01-01

    This software describes the transport and energy deposition of the passage of galactic cosmic rays in astronaut tissues during space travel, or heavy ion beams in patients in cancer therapy. Space radiation risk is a probability distribution, and time-dependent biological events must be accounted for physical description of space radiation transport in tissues and cells. A stochastic model can calculate the probability density directly without unverified assumptions about shape of probability density function. The prior art of transport codes calculates the average flux and dose of particles behind spacecraft and tissue shielding. Because of the signaling times for activation and relaxation in the cell and tissue, transport code must describe temporal and microspatial density of functions to correlate DNA and oxidative damage with non-targeted effects of signals, bystander, etc. These are absolutely ignored or impossible in the prior art. The GERM code provides scientists data interpretation of experiments; modeling of beam line, shielding of target samples, and sample holders; and estimation of basic physical and biological outputs of their experiments. For mono-energetic ion beams, basic physical and biological properties are calculated for a selected ion type, such as kinetic energy, mass, charge number, absorbed dose, or fluence. Evaluated quantities are linear energy transfer (LET), range (R), absorption and fragmentation cross-sections, and the probability of nuclear interactions after 1 or 5 cm of water equivalent material. In addition, a set of biophysical properties is evaluated, such as the Poisson distribution for a specified cellular area, cell survival curves, and DNA damage yields per cell. Also, the GERM code calculates the radiation transport of the beam line for either a fixed number of user-specified depths or at multiple positions along the Bragg curve of the particle in a selected material. The GERM code makes the numerical estimates of basic physical and biophysical quantities of high-energy protons and heavy ions that have been studied at the NASA Space Radiation Laboratory (NSRL) for the purpose of simulating space radiation biological effects. In the first option, properties of monoenergetic beams are treated. In the second option, the transport of beams in different materials is treated. Similar biophysical properties as in the first option are evaluated for the primary ion and its secondary particles. Additional properties related to the nuclear fragmentation of the beam are evaluated. The GERM code is a computationally efficient Monte-Carlo heavy-ion-beam model. It includes accurate models of LET, range, residual energy, and straggling, and the quantum multiple scattering fragmentation (QMSGRG) nuclear database.

  13. Event-based text mining for biology and functional genomics

    PubMed Central

    Thompson, Paul; Nawaz, Raheel; McNaught, John; Kell, Douglas B.

    2015-01-01

    The assessment of genome function requires a mapping between genome-derived entities and biochemical reactions, and the biomedical literature represents a rich source of information about reactions between biological components. However, the increasingly rapid growth in the volume of literature provides both a challenge and an opportunity for researchers to isolate information about reactions of interest in a timely and efficient manner. In response, recent text mining research in the biology domain has been largely focused on the identification and extraction of ‘events’, i.e. categorised, structured representations of relationships between biochemical entities, from the literature. Functional genomics analyses necessarily encompass events as so defined. Automatic event extraction systems facilitate the development of sophisticated semantic search applications, allowing researchers to formulate structured queries over extracted events, so as to specify the exact types of reactions to be retrieved. This article provides an overview of recent research into event extraction. We cover annotated corpora on which systems are trained, systems that achieve state-of-the-art performance and details of the community shared tasks that have been instrumental in increasing the quality, coverage and scalability of recent systems. Finally, several concrete applications of event extraction are covered, together with emerging directions of research. PMID:24907365

  14. Visualization of Sedentary Behavior Using an Event-Based Approach

    ERIC Educational Resources Information Center

    Loudon, David; Granat, Malcolm H.

    2015-01-01

    Visualization is commonly used in the interpretation of physical behavior (PB) data, either in conjunction with or as precursor to formal analysis. Effective representations of the data can enable the identification of patterns of behavior, and how they relate to the temporal context in a single day, or across multiple days. An understanding of

  15. Tsunami Warning Criteria for Cascadia events based on Tsunami models

    NASA Astrophysics Data System (ADS)

    Huang, P. Y.; Nyland, D. L.; Knight, W.; Gately, K.; Hale, D.; Urban, G.; Waddell, J.; Carrick, J.; Popham, C.; Bahng, B.; Kim, Y.; Burgy, M.; Langley, S.; Preller, C. C.; Whitmore, P.

    2013-12-01

    Initial tsunami warning, advisory, and watch zones for potential Cascadia earthquakes have been revised based on maximum expected threat for tsunamis generated by earthquakes in this region. Presently, alert zones are initially based on travel time for earthquakes greater than magnitude 7.8 with all areas less than three hours away from the source being put into a tsunami warning. The impact of this change is to reduce the length of coastline which is immediately put it into a warning status. Tsunami Warning Centers often delineate initial tsunami alert zones based on pre-set criteria dependent on earthquake magnitude, location, depth, and tsunami travel time. In many cases, this approach can lead to over-warning. Over the last several years, the West Coast/Alaska Tsunami Warning Center (WCATWC) has attempted to refine the amount of coastline immediately placed in a warning status based on maximum expected threat instead of travel time. Tsunami forecast models used to predict impacts during events (for example, Alaska Tsunami Forecast Model (ATFM), Short-term Inundation Forecasting for Tsunamis (SIFT), and Rapid Inundation Forecasting of Tsunamis (RIFT)) can also be used a-priori to delineate zones at-risk for specified source zones. forecast models have proven reasonably accurate during recent events. For the Cascadia Subduction zone, several rupture scenarios ranging from magnitude 7.9 to 9.2, were computed. Forecasted wave heights at various points are then used to set the initial Warning/Watch/Advisory regions. This procedure is more efficient than a blanket warning - or a refined warning based on travel times - as appropriate threat levels are assigned based on expected impact. For example, after a magnitude 8.7 earthquake in the southern Cascadia Subduction zone, southern and most of central California can be left out of the warning zone and placed in an advisory, as none of this region contains expected impacts in the warning threshold (tsunami amplitude over 1m). Under previous criteria, these zones would have been placed in a warning. Several examples are shown which help refine criteria used by the Tsunami Warning Center during hypothetical Cascadia events.

  16. An event-based architecture for solving constraint satisfaction problems

    NASA Astrophysics Data System (ADS)

    Mostafa, Hesham; Müller, Lorenz K.; Indiveri, Giacomo

    2015-12-01

    Constraint satisfaction problems are ubiquitous in many domains. They are typically solved using conventional digital computing architectures that do not reflect the distributed nature of many of these problems, and are thus ill-suited for solving them. Here we present a parallel analogue/digital hardware architecture specifically designed to solve such problems. We cast constraint satisfaction problems as networks of stereotyped nodes that communicate using digital pulses, or events. Each node contains an oscillator implemented using analogue circuits. The non-repeating phase relations among the oscillators drive the exploration of the solution space. We show that this hardware architecture can yield state-of-the-art performance on random SAT problems under reasonable assumptions on the implementation. We present measurements from a prototype electronic chip to demonstrate that a physical implementation of the proposed architecture is robust to practical non-idealities and to validate the theory proposed.

  17. An event-based architecture for solving constraint satisfaction problems

    PubMed Central

    Mostafa, Hesham; Müller, Lorenz K.; Indiveri, Giacomo

    2015-01-01

    Constraint satisfaction problems are ubiquitous in many domains. They are typically solved using conventional digital computing architectures that do not reflect the distributed nature of many of these problems, and are thus ill-suited for solving them. Here we present a parallel analogue/digital hardware architecture specifically designed to solve such problems. We cast constraint satisfaction problems as networks of stereotyped nodes that communicate using digital pulses, or events. Each node contains an oscillator implemented using analogue circuits. The non-repeating phase relations among the oscillators drive the exploration of the solution space. We show that this hardware architecture can yield state-of-the-art performance on random SAT problems under reasonable assumptions on the implementation. We present measurements from a prototype electronic chip to demonstrate that a physical implementation of the proposed architecture is robust to practical non-idealities and to validate the theory proposed. PMID:26642827

  18. Visualization of Sedentary Behavior Using an Event-Based Approach

    ERIC Educational Resources Information Center

    Loudon, David; Granat, Malcolm H.

    2015-01-01

    Visualization is commonly used in the interpretation of physical behavior (PB) data, either in conjunction with or as precursor to formal analysis. Effective representations of the data can enable the identification of patterns of behavior, and how they relate to the temporal context in a single day, or across multiple days. An understanding of…

  19. No-migration variance petition: Draft. Volume 4, Appendices DIF, GAS, GCR (Volume 1)

    SciTech Connect

    1995-05-31

    The Department of Energy is responsible for the disposition of transuranic (TRU) waste generated by national defense-related activities. Approximately 2.6 million cubic feet of the se waste have been generated and are stored at various facilities across the country. The Waste Isolation Pilot Plant (WIPP), was sited and constructed to meet stringent disposal requirements. In order to permanently dispose of TRU waste, the DOE has elected to petition the US EPA for a variance from the Land Disposal Restrictions of RCRA. This document fulfills the reporting requirements for the petition. This report is volume 4 of the petition which presents details about the transport characteristics across drum filter vents and polymer bags; gas generation reactions and rates during long-term WIPP operation; and geological characterization of the WIPP site.

  20. GCR access to the Moon as measured by the CRaTER instrument on LRO

    NASA Astrophysics Data System (ADS)

    Case, A. W.; Spence, H. E.; Golightly, M. J.; Kasper, J. C.; Blake, J. B.; Mazur, J. E.; Townsend, L. W.; Zeitlin, C. J.

    2010-10-01

    Recent modeling efforts have yielded varying and conflicting results regarding the possibility that Earth's magnetosphere is able to shield energetic particles of >10 MeV at lunar distances. This population of particles consists of galactic cosmic rays as well as energetic particles that are accelerated by solar flares and coronal mass ejections. The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) onboard the Lunar Reconnaissance Orbiter is in orbit about the Moon and is thus able to directly test these modeling results. Over the course of a month, CRaTER samples the upstream solar wind as well as various regions of Earth's magnetotail. CRaTER data from multiple lunations demonstrate that Earth's magnetosphere at lunar distances produces no measurable influence on energetic particle flux, even at the lowest energies (>14 MeV protons) where any effect should be maximized. For particles with energies of 14-30 MeV, we calculate an upper limit (determined by counting statistics) on the amount of shielding caused by the magnetosphere of 1.7%. The high energy channel (>500 MeV) provides an upper limit of 3.2%.

  1. Microstructure and corrosion behavior of hot-rolled GCr15 bearing steel

    NASA Astrophysics Data System (ADS)

    Fu, Junwei

    2016-04-01

    Microstructure, corrosion behavior and evolution of hot-rolled high-carbon-chromium bearing steel were investigated using scanning electron microscopy and energy dispersive spectrometer (EDS). The results show that corrosion initiates adjacent to the network carbide, which is the initial austenite grain boundary. With the further increase in corrosion time, corrosion fraction is increased and extended into the grains. Finally, the whole grain near the network carbide is etched off and the grain boundary is detached from the sample, which forms the corroded holes. Based on the EDS analyses, it is confirmed that this corrosion behavior is resulted from the depletion of Cr as solid solute at the grain boundary. The depletion of Cr is the result of the formation of Cr carbide near the grain boundary.

  2. Solar modulation of GCR electrons over the 23rd solar minimum with PAMELA

    NASA Astrophysics Data System (ADS)

    Munini, R.; Di Felice, V.; Adriani, O.; Barbarino, G. C.; Bazilevskaya, G. A.; Bellotti, R.; Boezio, M.; Bogomolov, E. A.; Bongi, M.; Bonvicini, V.; Bottai, S.; Bruno, A.; Cafagna, F.; Campana, D.; Carlson, P.; Casolino, M.; Castellini, G.; De Donato, C.; De Santis, C.; De Simone, N.; Formato, V.; Galper, A. M.; Karelin, A. V.; Koldashov, S. V.; Koldobskiy, S.; Krutkov, S. Y.; Kvashnin, A. N.; Leonov, A.; Malakhov, V.; Marcelli, L.; Martucci, M.; Mayorov, A. G.; Menn, W.; Merge, M.; Mikhailov, V. V.; Mocchiutti, E.; Monaco, A.; Mori, N.; Osteria, G.; Palma, F.; Panico, B.; Papini, P.; Pearce, M.; Picozza, P.; Ricci, M.; Ricciarini, S. B.; Sarkar, R.; Scotti, V.; Simon, M.; Sparvoli, R.; Spillantini, P.; Stozhkov, Y. I.; Vacchi, A.; Vannuccini, E.; Vasilyev, G.; Voronov, S. A.; Yurkin, Y. T.; Zampa, G.; Zampa, N.; Potgieter, M. S.; Vos, E. E.

    2015-08-01

    The satellite-borne PAMELA experiment has been continuously collecting data since 15th June 2006, when it was launched from the Baikonur cosmodrome to detect the charged component of cosmic rays over a wide energy range and with unprecedented statistics. The apparatus design is particularly suited for particle and antiparticle identification. The PAMELA experiment has measured the electron spectrum at Earth in great detail, extending up to about 100 GeV and down to about 200 MeV. The galactic cosmic ray electron spectra for 2007 and 2009, i.e. measured during the A<0 solar minimum of solar cycle 23, are presented. These fluxes provide important information for the study of charge dependent solar modulation effects.

  3. Draft no-migration variance petition. Volume 5, Appendices: GCR (Vol. 2), HSC, PAR

    SciTech Connect

    1995-05-31

    The Department of Energy is responsible for the disposition of transuranic (TRU) waste generated by national defense-related activities. Approximately 2,6 million cubic feet of these waste have been generated and are stored at various facilities across the country. The Waste Isolation Pilot Plant (WIPP), was sited and constructed to meet stringent disposal requirements. In order to permanently dispose of TRU waste, the DOE has elected to petition the US EPA for a variance from the Land Disposal Restrictions of RCRA. This document fulfills the reporting requirements for the petition. This is Volume 5 of the petition which present details about the geological characterization report, average VOC concentration calculations, and the permeability and porosity of the salado formation.

  4. Draft Title 40 CFR 191 compliance certification application for the Waste Isolation Pilot Plant. Volume 7: Appendix GCR Volume 2

    SciTech Connect

    1995-03-31

    This report contains the second part of the geological characterization report for the Waste Isolation Pilot Plant. Both hydrology and geochemistry are evaluated. The following aspects of hydrology are discussed: surface hydrology; ground water hydrology; and hydrology drilling and testing. Hydrologic studies at the site and adjacent site areas have concentrated on defining the hydrogeology and associated salt dissolution phenomena. The geochemical aspects include a description of chemical properties of geologic media presently found in the surface and subsurface environments of southeastern New Mexico in general, and of the proposed WIPP withdrawal area in particular. The characterization does not consider any aspect of artificially-introduced material, temperature, pressure, or any other physico-chemical condition not native to the rocks of southeastern New Mexico.

  5. Prediction problem for target events based on the inter-event waiting time

    NASA Astrophysics Data System (ADS)

    Shapoval, A.

    2010-11-01

    In this paper we address the problem of forecasting the target events of a time series given the distribution ξ of time gaps between target events. Strong earthquakes and stock market crashes are the two types of such events that we are focusing on. In the series of earthquakes, as McCann et al. show [W.R. Mc Cann, S.P. Nishenko, L.R. Sykes, J. Krause, Seismic gaps and plate tectonics: seismic potential for major boundaries, Pure and Applied Geophysics 117 (1979) 1082-1147], there are well-defined gaps (called seismic gaps) between strong earthquakes. On the other hand, usually there are no regular gaps in the series of stock market crashes [M. Raberto, E. Scalas, F. Mainardi, Waiting-times and returns in high-frequency financial data: an empirical study, Physica A 314 (2002) 749-755]. For the case of seismic gaps, we analytically derive an upper bound of prediction efficiency given the coefficient of variation of the distribution ξ. For the case of stock market crashes, we develop an algorithm that predicts the next crash within a certain time interval after the previous one. We show that this algorithm outperforms random prediction. The efficiency of our algorithm sets up a lower bound of efficiency for effective prediction of stock market crashes.

  6. System architecture for supporting event-based interaction and information access

    NASA Astrophysics Data System (ADS)

    Drew, Richard S.; Morris, David; Dew, Peter M.; Leigh, Christine

    1996-03-01

    The University of Leeds Virtual Science Park (VSP) is an example of a virtual working system for supporting the provision of a number of services, including virtual consultancy, workbased learning, consortium building and access to information. This paper presents a new architecture based on event mechanisms. The extensions fall into 3 areas: provision of timely, up-to-date information based on users' interests; integration with existing information sources; and chance interaction. The main problems addressed are facilities for keeping the VSP information up to date and keeping users notified of relevant changes to the data. Integration with existing data sources is also key to the provision of an information space capable of supporting VSP services. We describe an event mechanism to support information location, information monitoring, chance interaction and integration with existing information sources. The system will be used in a VSP Workbased learning project for supplying multimedia information and collaboration facilities to remote students to support distance learning. A World Wide Web gateway has also been developed to provide wide scale access to the VSP.

  7. Event based statistics from high spatial and temporal resolution gauge and radar data

    NASA Astrophysics Data System (ADS)

    Berg, Peter; Eggert, Bastian; Haerter, Jan; Moseley, Christopher

    2013-04-01

    Studies of extreme precipitation is often focused on daily resolution and for point measurements, i.e. gauge data. A main problem with this coarse temporal resolution is the strong averaging effect on short events. Here we present a study based on high temporal resolution (five minutes) data from radar (1x1 km horizontal resolution) and a high spatial density gauge data set over southwestern Germany. For the gauge data, an event is defined as a sequence of consecutive precipitation measurements above the measurement threshold, while for radar data the events are defined as continuous horizontal regions with above measurement limit intensities. With samples from about two years of data for the radar and from about 90 gauges each with 8 years of data, we get solid statistics for different aspects of the event distributions. A strong relationship between the temporal and spatial definitions of events is found. Additional use of synoptic observations allow the distinction of convective and stratiform precipitation types. The two types show largely different intensity distributions and characteristics for both spatial and temporal statistics. With probability and intensity distributions of the events, it is possible to calculate statistics of the precipitation yield from different duration (or size) events. We found that the yield from stratiform events decrease in a near power-law manner, while convective precipitation shows a concave dependence an a log-log scale, with the largest yields for events of around 20 minutes duration or 30 km2 area. The results emphasise the utility of high temporal resolution data of less than one hour, which allows proper resolution of convective showers and additionally to derive event statistics, which are important for impact assessments.

  8. Correction for missed events based on a realistic model of a detector.

    PubMed Central

    Draber, S; Schultze, R

    1994-01-01

    Quantitative patch-clamp analysis based on dwell-time histograms has to deal with the problem of missed events. The correction of the evaluated time constants has to take into account the characteristics of the detector used for the reconstruction of the time series. In previous approaches a simple model of the detector has been used, which is based on the assumption that all events shorter than the temporal resolution tres were missed, irrespective of the preceding events. Rather than the standard assumption of a fixed dead time, we introduce a more realistic model of a detector by a continuous-time version of the Hinkley detector. The combined state of the channel and the detector obeys a Markov model, which is governed by a Fokker-Planck-Kolmogorov partial differential equation. The steady-state solution leads to the determination of the apparent time constants tau o and tau c depending on the true rate constants koc and kco and the temporal resolution tres of the detector. Simulations with different kinds of detectors, including the Bessel filter with half-amplitude threshold detection, are performed. They show that our new equation predicts the dependence of tau c and tau o on koc, kco, and tres better than the standard equation used until now. PMID:7510527

  9. A mobile robots experimental environment with event-based wireless communication.

    PubMed

    Guinaldo, María; Fábregas, Ernesto; Farias, Gonzalo; Dormido-Canto, Sebastián; Chaos, Dictino; Sánchez, José; Dormido, Sebastián

    2013-01-01

    An experimental platform to communicate between a set of mobile robots through a wireless network has been developed. The mobile robots get their position through a camera which performs as sensor. The video images are processed in a PC and a Waspmote card sends the corresponding position to each robot using the ZigBee standard. A distributed control algorithm based on event-triggered communications has been designed and implemented to bring the robots into the desired formation. Each robot communicates to its neighbors only at event times. Furthermore, a simulation tool has been developed to design and perform experiments with the system. An example of usage is presented. PMID:23881139

  10. Prediction of consequences of meteor events based on atmospheric trajectory analysis

    NASA Astrophysics Data System (ADS)

    Kuznetsova, D.; Gritsevich, M.; Christou, A.

    2014-07-01

    In this study, we develop a model which describes how meteoroid enter the atmosphere of a planet, and categorize different consequences of the collisions of cosmic bodies with the atmosphere and the surface of a planet. We focus on two types of possible results: (1) meteorite fall, when a fragment of a meteoroid can be found on the surface, and (2) full ablation, when meteoroid does not reach the ground. The model is based on the analytical solution of the classical equations of meteor-body deceleration [1,2]. The dimensionless solution for the mass-velocity dependence and the height-velocity dependence can be expressed using two main dimensionless parameters: the ballistic coefficient, which shows the ratio between the mass of the atmospheric column along the trajectory and the body's pre-entry mass, and the mass loss parameter, which is proportional to the ratio between the initial kinetic energy of the body and energy required to insure total mass loss of the body due to ablation and fragmentation. Thus, every given meteoroid case is described by a pair of these parameters. To distinguish the two possible impact consequences (meteorite fall or full ablation) we use the meteorite fall condition: the terminal mass of a meteoroid exceeds or is equal to a certain chosen value. This condition can be written using the parameters introduced above. Thus, we get a boundary curve in the parameter plane and associate different events with the location of the point relative to this curve. This theory is applied in the classification of collisions of cosmic bodies with the Earth's atmosphere and surface. The observational data are used to calculate the values of the parameters used in current study, and these values are shown in the parameter plane and their locations are compared against the location of boundary curve in each case. The obtained results show a good agreement with the known consequences for the observed fireballs, including ones registered by the Canadian, Prairie and European Fireball Networks [3,4]. As an extension of this theory, we model the meteoroid entry into the Martian atmosphere using introduced parameters. A number of investigations by different authors show an increasing interest to this subject, e.g. [5--9]. To apply our theory, we take two meteoroid types as an example: a chondrite with the entry velocity 10 km/s, and an iron meteoroid with the entry velocity 15 km/s. For each type, we take several pre-entry mass values and show the impact consequences by constructing the boundary curve on the parameter plane and the point corresponding to the meteoroid. These results are also compared with the meteoroid entries into the terrestrial atmosphere with the same pre-entry characteristics. It is shown that for some pre-entry mass range, a meteoroid would be fully ablated for the case of Earth, but a fraction of it would reach the surface for the case of Mars.

  11. Issues in Informal Education: Event-Based Science Communication Involving Planetaria and the Internet

    NASA Technical Reports Server (NTRS)

    Adams, M.; Gallagher, D. L.; Whitt, A.; Six, N. Frank (Technical Monitor)

    2002-01-01

    For the past four years the Science Directorate at Marshall Space Flight Center has carried out a diverse program of science communication through the web resources on the Internet. The program includes extended stories about NAS.4 science, a curriculum resource for teachers tied to national education standards, on-line activities for students, and webcasts of real-time events. Events have involved meteor showers, solar eclipses, natural very low frequency radio emissions, and amateur balloon flights. In some cases broadcasts accommodate active feedback and questions from Internet participants. We give here, examples of events, problems, and lessons learned from these activities.

  12. Issues in Informal Education: Event-Based Science Communication Involving Planetaria and the Internet

    NASA Technical Reports Server (NTRS)

    Adams, Mitzi L.; Gallagher, D. L.; Whitt, A.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    For the last several years the Science Directorate at Marshall Space Flight Center has carried out a diverse program of Internet-based science communication. The program includes extended stories about NASA science, a curriculum resource for teachers tied to national education standards, on-line activities for students, and webcasts of real-time events. The focus of sharing real-time science related events has been to involve and excite students and the public about science. Events have involved meteor showers, solar eclipses, natural very low frequency radio emissions, and amateur balloon flights. In some cases broadcasts accommodate active feedback and questions from Internet participants. Panel participation will be used to communicate the problems and lessons learned from these activities over the last three years.

  13. Prediction and evaluation of solar particle events based on precursor information.

    PubMed

    Heckman, G R; Kunches, J M; Allen, J H

    1992-01-01

    Protection from the radiation effects of solar particle events for deep space mission crews requires a warning system to observe solar flares and predict subsequent charged particle fluxes. Such a system relates precursor information observed in each flare to the intensity, delay, and duration of the subsequent Solar Particle Event (SPE) at other locations in the solar system. A warning system of this type is now in operation at the NOAA Space Environment Services Center in Boulder, Colorado for support of space missions. It has been used to predict flare particle fluxes at the earth for flares of Solar Cycle 22. The flare parameters used and the effectiveness of the current warning system, based on Solar Cycle 22 experience, are presented, with an examination of the shortcomings. Needed improvements to the system include more complete observations of solar activity, especially information on the occurrences of solar mass ejections; and consideration of the effects of propagation conditions in the solar corona and interplanetary medium. Requirements for solar observations and forecasting systems on board the spacecraft are discussed. PMID:11537021

  14. Projected changes in extreme temperature events based on the NARCCAP model suite

    NASA Astrophysics Data System (ADS)

    Horton, Radley M.; Coffel, Ethan D.; Winter, Jonathan M.; Bader, Daniel A.

    2015-09-01

    Once-per-year (annual) maximum temperature extremes in North American Regional Climate Change Assessment Program (NARCCAP) models are projected to increase more (less) than mean daily maximum summer temperatures over much of the eastern (western) United States. In contrast, the models almost everywhere project greater warming of once-per-year minimum temperatures as compared to mean daily minimum winter temperatures. Under projected changes associated with extremes of the temperature distribution, Baltimore's maximum temperature that was met or exceeded once per year historically is projected to occur 17 times per season by midcentury, a 28% increase relative to projections based on summer mean daily maximum temperature change. Under the same approach, historical once-per-year cold events in Baltimore are projected to occur once per decade. The models are generally able to capture observed geopotential height anomalies associated with temperature extremes in two subregions. Projected changes in extreme temperature events cannot be explained by geopotential height anomalies or lower boundary conditions as reflected by soil moisture anomalies or snow water equivalent.

  15. Event based analysis of chlorothalonil concentrations following application to managed turf.

    PubMed

    King, Kevin W; Balogh, James C

    2013-03-01

    Chlorothalonil concentrations exceeding acute toxicity levels for certain organisms have been measured in surface water discharge events from managed turf watersheds. The duration of exceedence and the timing of these events related to precipitation/runoff and time since application, however, have not been explored. Chlorothalonil concentrations were measured from discharge waters draining a managed turf watershed in Duluth, Minnesota, USA, between 2003 and 2009. The median chlorothalonil concentration was 0.58 µg/L. Approximately 2% of all measured concentrations exceeded the 7.6 µg/L median lethal concentration (LC50) acute toxicity level for rainbow trout. One-twentieth the LC50 concentration, equivalent to the level of concern (0.38 µg/L) for endangered species, was exceeded 31% of the time during the present study. The concentrations that exceeded the LC50 threshold were associated with eight rainfall/runoff events. Low dose exposures are a more important biological concern than acute occurrences. Exceedence concentrations associated with acute effects were significantly (p < 0.05) correlated to time since application and were measured only in the fall following extensive application. A conflict exists between the transportability of chlorothalonil as suggested by its chemical properties and the data collected in the present study. With respect to course-wide golf course application, avoiding application until after the major autumn rainfall period but before the first snow coverage is recommended to reduce occurrence of chlorothalonil concentrations that exceed toxic levels associated with acute and chronic levels of concern. PMID:23233324

  16. The Relationship between Event-Based Prospective Memory and Ongoing Task Performance in Chimpanzees (Pan troglodytes)

    PubMed Central

    Evans, Theodore A.; Perdue, Bonnie; Beran, Michael J.

    2014-01-01

    Prospective memory is remembering to do something at a future time. A growing body of research supports that prospective memory may exist in nonhuman animals, but the methods used to test nonhuman prospective memory differ from those used with humans. The current work tests prospective memory in chimpanzees using a method that closely approximates a typical human paradigm. In these experiments, the prospective memory cue was embedded within an ongoing task. Tokens representing food items could be used in one of two ways: in a matching task with pictures of items (the ongoing task) or to request a food item hidden in a different location at the beginning of the trial. Chimpanzees had to disengage from the ongoing task in order to use the appropriate token to obtain a higher preference food item. In Experiment 1, chimpanzees effectively matched tokens to pictures, when appropriate, and disengaged from the ongoing task when the token matched the hidden item. In Experiment 2, performance did not differ when the target item was either hidden or visible. This suggested no effect of cognitive load on either the prospective memory task or the ongoing task, but performance was near ceiling, which may have contributed to this outcome. In Experiment 3, we created a more challenging version of the task. More errors on the matching task occurred before the prospective memory had been carried out, and this difference seemed to be limited to the hidden condition. This finding parallels results from human studies and suggests that working memory load and prospective memory may have a similar relationship in nonhuman primates. PMID:25372809

  17. Landslide susceptibility analysis by means of event-based multi-temporal landslide inventories

    NASA Astrophysics Data System (ADS)

    Tseng, C. M.; Lin, C. W.; Hsieh, W. D.

    2015-02-01

    This study uses landslide inventory of a single typhoon event and Weight of Evidence (WOE) analysis to establish landslide susceptibility map of the Laonung River in southern Taiwan. Eight factors including lithology, elevation, slope, slope aspect, landform, Normalized Difference Vegetation Index (NDVI), distance to geological structure, and distance to stream are used to evaluate the susceptibility of landslide. Effect analysis and the assessment of grouped factors showed that lithology, slope, elevation, and NDVI are the dominant factors of landslides in the study area. Landslide susceptibility analysis with these four factors achieves over 90% of the AUC (area under curve) of the success rate curve of all eight factors. Four landslide susceptibility models for four typhoons from 2007 to 2009 are established, and each model is cross validated. Results indicate that the best model should be constructed by using landslide inventory close to the landslide occurrence threshold and should reflect the most common spatial rainfall pattern in the study region for ideal simulation and validation results. The prediction accuracy of the best model in this study reached 90.2%. The two highest susceptibility categories (very high and high levels) cover around 80% of the total landslides in the study area.

  18. Event based analysis of Chlorothalonil concentrations following application to managed turf

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chlorothalonil concentrations exceeding acute toxicity levels for certain organisms have been measured in surface water discharge events from managed turf watersheds. However, the duration of exceedence and the timing of those events with respect to precipitation/runoff and time since application ha...

  19. A Mobile Robots Experimental Environment with Event-Based Wireless Communication

    PubMed Central

    Guinaldo, María; Fábregas, Ernesto; Farias, Gonzalo; Dormido-Canto, Sebastián; Chaos, Dictino; Sánchez, José; Dormido, Sebastián

    2013-01-01

    An experimental platform to communicate between a set of mobile robots through a wireless network has been developed. The mobile robots get their position through a camera which performs as sensor. The video images are processed in a PC and a Waspmote card sends the corresponding position to each robot using the ZigBee standard. A distributed control algorithm based on event-triggered communications has been designed and implemented to bring the robots into the desired formation. Each robot communicates to its neighbors only at event times. Furthermore, a simulation tool has been developed to design and perform experiments with the system. An example of usage is presented. PMID:23881139

  20. An event-based neural network architecture with an asynchronous programmable synaptic memory.

    PubMed

    Moradi, Saber; Indiveri, Giacomo

    2014-02-01

    We present a hybrid analog/digital very large scale integration (VLSI) implementation of a spiking neural network with programmable synaptic weights. The synaptic weight values are stored in an asynchronous Static Random Access Memory (SRAM) module, which is interfaced to a fast current-mode event-driven DAC for producing synaptic currents with the appropriate amplitude values. These currents are further integrated by current-mode integrator synapses to produce biophysically realistic temporal dynamics. The synapse output currents are then integrated by compact and efficient integrate and fire silicon neuron circuits with spike-frequency adaptation and adjustable refractory period and spike-reset voltage settings. The fabricated chip comprises a total of 32 × 32 SRAM cells, 4 × 32 synapse circuits and 32 × 1 silicon neurons. It acts as a transceiver, receiving asynchronous events in input, performing neural computation with hybrid analog/digital circuits on the input spikes, and eventually producing digital asynchronous events in output. Input, output, and synaptic weight values are transmitted to/from the chip using a common communication protocol based on the Address Event Representation (AER). Using this representation it is possible to interface the device to a workstation or a micro-controller and explore the effect of different types of Spike-Timing Dependent Plasticity (STDP) learning algorithms for updating the synaptic weights values in the SRAM module. We present experimental results demonstrating the correct operation of all the circuits present on the chip. PMID:24681923

  1. An events based algorithm for distributing concurrent tasks on multi-core architectures

    NASA Astrophysics Data System (ADS)

    Holmes, David W.; Williams, John R.; Tilke, Peter

    2010-02-01

    In this paper, a programming model is presented which enables scalable parallel performance on multi-core shared memory architectures. The model has been developed for application to a wide range of numerical simulation problems. Such problems involve time stepping or iteration algorithms where synchronization of multiple threads of execution is required. It is shown that traditional approaches to parallelism including message passing and scatter-gather can be improved upon in terms of speed-up and memory management. Using spatial decomposition to create orthogonal computational tasks, a new task management algorithm called H-Dispatch is developed. This algorithm makes efficient use of memory resources by limiting the need for garbage collection and takes optimal advantage of multiple cores by employing a "hungry" pull strategy. The technique is demonstrated on a simple finite difference solver and results are compared to traditional MPI and scatter-gather approaches. The H-Dispatch approach achieves near linear speed-up with results for efficiency of 85% on a 24-core machine. It is noted that the H-Dispatch algorithm is quite general and can be applied to a wide class of computational tasks on heterogeneous architectures involving multi-core and GPGPU hardware.

  2. Event-based Modeling of Fecal Coliform Concentrations in Runoff from Manured Fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantitative evaluation of the effect of field manure application on bacterial concentrations in creeks adjacent to the field requires developing microbial transport models. Reliable testing of such models with bacteria monitoring data requires a better understanding and estimation of the uncertaint...

  3. Suspended solids transport: an analysis based on turbidity measurements and event based fully calibrated hydrodynamic models.

    PubMed

    Langeveld, J G; Veldkamp, R G; Clemens, F

    2005-01-01

    Modelling suspended solids transport is a key issue for predicting the pollution load discharged by CSOs. Nonetheless, there is still much debate on the main drivers for suspended solids transport and on the modelling approach to be adopted. Current sewer models provide suspended solids transport models. These models, however, rely upon erosion-deposition criteria developed in fluvial environments, therewith oversimplifying the sewer sediment characteristics. Consequently, the performance of these models is poor from a theoretical point of view. To get an improved understanding of the temporal and spatial variations in suspended solids transport, a measuring network was installed in the sewer system of Loenen in conjunction with a hydraulic measuring network from June through December 2001. During the measuring period, 15 storm events rendered high-quality data on both the hydraulics and the turbidity. For each storm event, a hydrodynamic model was calibrated using the Clemens' method. The conclusion of the paper is that modelling of suspended solids transport has been and will be one of the challenges in the field of urban drainage modelling. A direct relation of either shear stress or flow velocity with turbidity could not be found, likely because of the time varying characteristics of the suspended solids. PMID:16206848

  4. Adverse Drug Events-based Tumor Stratification for Ovarian Cancer Patients Receiving Platinum Therapy

    PubMed Central

    Wang, Chen; Zimmermann, Michael T.; Chute, Christopher G.; Jiang, Guoqian

    2015-01-01

    The underlying molecular mechanisms of adverse drug events (ADEs) associated with cancer therapy drugs may overlap with their antineoplastic mechanisms. In a previous study, we developed an ADE-based tumor stratification framework (known as ADEStrata) with a case study of breast cancer patients receiving aromatase inhibitors, and demonstrated that the prediction of per-patient ADE propensity simultaneously identifies high-risk patients experiencing poor outcomes. In this study, we aim to evaluate the ADEStrata framework with a different tumor type and chemotherapy class – ovarian cancer treated with platinum chemotherapeutic drugs. We identified a cohort of ovarian cancer patients receiving cisplatin (a standard platinum therapy) from The Cancer Genome Atlas (TCGA) (n=156). We demonstrated that somatic variant prioritization guided by known ADEs associated with cisplatin could be used to stratify patients treated with cisplatin and uncover tumor subtypes with different clinical outcomes. PMID:26306234

  5. Frequency analysis of extreme events based on precipitation station data over southeastern Brazil

    NASA Astrophysics Data System (ADS)

    Zilli, M. T.; Carvalho, L. V.

    2013-12-01

    The southeastern coast (SE) of Brazil is among the most densely populated areas of eastern South America with population largely concentrated in urban centers. Due to complex terrain and chaotic urbanization, this region is subject to a variety of natural disasters, including but not limited to floods and landslides that frequently occur during the austral summer (September to March). The South American Monsoon System (SAMS) and the South Atlantic Convergence zone (SACZ) are the most important climatic features that affect precipitation regimes in SE Brazil during the Austral summer. Previous studies have shown an overall increasing trend in daily precipitation and consequently in extreme events in SE Brazil. Future scenarios of climate change seem to indicate that SAMS daily precipitation will likely continue to increase throughout the 21st century. However, the rainfall response to the predicted warming is heterogeneous, and there is large uncertainty in the projected rainfall change and corresponding regional-to-local impacts. Some observational studies have demonstrated a positive trend in the frequency of extreme events in particular locations. Nevertheless, these analyses either focus on one single station or investigate relatively short periods. This study further investigates interannual to multiannual variations and changes in the frequency of daily extreme precipitation events in SE Brazil using long time series from a set of rain gauges stations. The analyzed rain gauge stations are located along the coastal area of SE Brazil (between 18°S and 25°S) and have at least 74 years of daily data, with less than 5% missing. The period of analysis varies slightly from station to station, but roughly all stations have data between 1930 and 2012. The analysis of the frequency of extreme events is based on the Peaks-over-Threshold (POT) approach, which follows a General Pareto Distribution (GPD), under the independent identically distributed assumption. Furthermore, these approaches can be applied to non-stationary series, as they are based on time dependent thresholds composed by the extreme quantiles of the daily rainfall. The presence of annual trend is also tested using a non-parametric Mann-Kendall test. In addition, the stations encompass the area with large influence of the SACZ. This study also investigates stations located at the margin of the climatological position of the SACZ, in order to contrast the importance of the convergence zone for trends in extreme precipitation.

  6. Bonsai: an event-based framework for processing and controlling data streams.

    PubMed

    Lopes, Gonçalo; Bonacchi, Niccolò; Frazão, João; Neto, Joana P; Atallah, Bassam V; Soares, Sofia; Moreira, Luís; Matias, Sara; Itskov, Pavel M; Correia, Patrícia A; Medina, Roberto E; Calcaterra, Lorenza; Dreosti, Elena; Paton, Joseph J; Kampff, Adam R

    2015-01-01

    The design of modern scientific experiments requires the control and monitoring of many different data streams. However, the serial execution of programming instructions in a computer makes it a challenge to develop software that can deal with the asynchronous, parallel nature of scientific data. Here we present Bonsai, a modular, high-performance, open-source visual programming framework for the acquisition and online processing of data streams. We describe Bonsai's core principles and architecture and demonstrate how it allows for the rapid and flexible prototyping of integrated experimental designs in neuroscience. We specifically highlight some applications that require the combination of many different hardware and software components, including video tracking of behavior, electrophysiology and closed-loop control of stimulation. PMID:25904861

  7. An event-based approach to understanding decadal fluctuations in the Atlantic meridional overturning circulation

    NASA Astrophysics Data System (ADS)

    Allison, Lesley; Hawkins, Ed; Woollings, Tim

    2015-01-01

    Many previous studies have shown that unforced climate model simulations exhibit decadal-scale fluctuations in the Atlantic meridional overturning circulation (AMOC), and that this variability can have impacts on surface climate fields. However, the robustness of these surface fingerprints across different models is less clear. Furthermore, with the potential for coupled feedbacks that may amplify or damp the response, it is not known whether the associated climate signals are linearly related to the strength of the AMOC changes, or if the fluctuation events exhibit nonlinear behaviour with respect to their strength or polarity. To explore these questions, we introduce an objective and flexible method for identifying the largest natural AMOC fluctuation events in multicentennial/multimillennial simulations of a variety of coupled climate models. The characteristics of the events are explored, including their magnitude, meridional coherence and spatial structure, as well as links with ocean heat transport and the horizontal circulation. The surface fingerprints in ocean temperature and salinity are examined, and compared with the results of linear regression analysis. It is found that the regressions generally provide a good indication of the surface changes associated with the largest AMOC events. However, there are some exceptions, including a nonlinear change in the atmospheric pressure signal, particularly at high latitudes, in HadCM3. Some asymmetries are also found between the changes associated with positive and negative AMOC events in the same model. Composite analysis suggests that there are signals that are robust across the largest AMOC events in each model, which provides reassurance that the surface changes associated with one particular event will be similar to those expected from regression analysis. However, large differences are found between the AMOC fingerprints in different models, which may hinder the prediction and attribution of such events in reality.

  8. Event-Based Modeling of Driver Yielding Behavior at Unsignalized Crosswalks

    PubMed Central

    Schroeder, Bastian J.; Rouphail, Nagui M.

    2011-01-01

    This research explores factors associated with driver yielding behavior at unsignalized pedestrian crossings and develops predictive models for yielding using logistic regression. It considers the effect of variables describing driver attributes, pedestrian characteristics and concurrent conditions at the crosswalk on the yield response. Special consideration is given to ‘vehicle dynamics constraints’ that form a threshold for the potential to yield. Similarities are identified to driver reaction in response to the ‘amber’ indication at a signalized intersection. The logit models were developed from data collected at two unsignalized mid-block crosswalks in North Carolina. The data include ‘before’ and ‘after’ observations of two pedestrian safety treatments, an in-street pedestrian crossing sign and pedestrian-actuated in-roadway warning lights. The analysis suggests that drivers are more likely to yield to assertive pedestrians who walk briskly in their approach to the crosswalk. In turn, the yield probability is reduced with higher speeds, deceleration rates and if vehicles are traveling in platoons. The treatment effects proved to be significant and increased the propensity of drivers to yield, but their effectiveness may be dependent on whether the pedestrian activates the treatment. The results of this research provide new insights on the complex interaction of pedestrians and vehicles at unsignalized intersections and have implications for future work towards predictive models for driver yielding behavior. The developed logit models can provide the basis for representing driver yielding behavior in a microsimulation modeling environment. PMID:21852892

  9. Event-Based Plausibility Immediately Influences On-Line Language Comprehension

    ERIC Educational Resources Information Center

    Matsuki, Kazunaga; Chow, Tracy; Hare, Mary; Elman, Jeffrey L.; Scheepers, Christoph; McRae, Ken

    2011-01-01

    In some theories of sentence comprehension, linguistically relevant lexical knowledge, such as selectional restrictions, is privileged in terms of the time-course of its access and influence. We examined whether event knowledge computed by combining multiple concepts can rapidly influence language understanding even in the absence of selectional…

  10. Event-based stormwater quality and quantity loadings from elevated urban infrastructure affected by transportation.

    PubMed

    Sansalone, John J; Hird, Jonathan P; Cartledge, Frank K; Tittlebaum, Marty E

    2005-01-01

    Urban-rainfall runoff affected by transportation is a complex matrix of a very wide gradation of particulate matter (< 1 to > 10 000 microm) and dissolved inorganic and organic constituents. Particulate matter transported by rainfall runoff can be a significant vector for many reactive particulate-bound constituents, particularly metal elements. The water quality and hydrology of nine events from a representative elevated section of Interstate 10 (I-10) (eastbound average daily traffic load of 70 400 vehicles) in Baton Rouge, Louisiana, were characterized and compared with respect to the passage of each hydrograph. Residence time on the paved concrete surface was less than 30 minutes for all events. Results indicate that event-mean concentrations (EMCs) of particulate matter as total-suspended solids (TSS) (138 to 561 mg/L) and chemical-oxygen demand (COD) (128 to 1440 mg/L) were greater than those found in untreated municipal wastewater from the same service area. Particulate-matter dissolution and COD partitioned as a function of pH, pavement residence time, and organic content. In general, delivery of mass for aggregate indices, such as particulate matter (measured as TSS) and COD mass, were driven by the hydrology of the event, while concentrations of aggregate-constituent measurements, such as total-dissolved solids (TDS), illustrated an exponential-type decline during the rising limb of the hydrograph. Despite the short residence times, wide solids gradation, partitioning, and complexity of the rainfall-runoff chemistry, conductivity and dissolved solids were strongly correlated. Characterization of the transport and loads of constituents in urban-rainfall runoff, as a function of hydrology, is a necessary first step when considering treatability, structural or nonstructural controls, and mass trading for discharges from paved infrastructure. PMID:16121503

  11. Bonsai: an event-based framework for processing and controlling data streams

    PubMed Central

    Lopes, Gonçalo; Bonacchi, Niccolò; Frazão, João; Neto, Joana P.; Atallah, Bassam V.; Soares, Sofia; Moreira, Luís; Matias, Sara; Itskov, Pavel M.; Correia, Patrícia A.; Medina, Roberto E.; Calcaterra, Lorenza; Dreosti, Elena; Paton, Joseph J.; Kampff, Adam R.

    2015-01-01

    The design of modern scientific experiments requires the control and monitoring of many different data streams. However, the serial execution of programming instructions in a computer makes it a challenge to develop software that can deal with the asynchronous, parallel nature of scientific data. Here we present Bonsai, a modular, high-performance, open-source visual programming framework for the acquisition and online processing of data streams. We describe Bonsai's core principles and architecture and demonstrate how it allows for the rapid and flexible prototyping of integrated experimental designs in neuroscience. We specifically highlight some applications that require the combination of many different hardware and software components, including video tracking of behavior, electrophysiology and closed-loop control of stimulation. PMID:25904861

  12. The relationship between event-based prospective memory and ongoing task performance in chimpanzees (Pan troglodytes).

    PubMed

    Evans, Theodore A; Perdue, Bonnie; Beran, Michael J

    2014-01-01

    Prospective memory is remembering to do something at a future time. A growing body of research supports that prospective memory may exist in nonhuman animals, but the methods used to test nonhuman prospective memory differ from those used with humans. The current work tests prospective memory in chimpanzees using a method that closely approximates a typical human paradigm. In these experiments, the prospective memory cue was embedded within an ongoing task. Tokens representing food items could be used in one of two ways: in a matching task with pictures of items (the ongoing task) or to request a food item hidden in a different location at the beginning of the trial. Chimpanzees had to disengage from the ongoing task in order to use the appropriate token to obtain a higher preference food item. In Experiment 1, chimpanzees effectively matched tokens to pictures, when appropriate, and disengaged from the ongoing task when the token matched the hidden item. In Experiment 2, performance did not differ when the target item was either hidden or visible. This suggested no effect of cognitive load on either the prospective memory task or the ongoing task, but performance was near ceiling, which may have contributed to this outcome. In Experiment 3, we created a more challenging version of the task. More errors on the matching task occurred before the prospective memory had been carried out, and this difference seemed to be limited to the hidden condition. This finding parallels results from human studies and suggests that working memory load and prospective memory may have a similar relationship in nonhuman primates. PMID:25372809

  13. Event-Based Plausibility Immediately Influences On-Line Language Comprehension

    ERIC Educational Resources Information Center

    Matsuki, Kazunaga; Chow, Tracy; Hare, Mary; Elman, Jeffrey L.; Scheepers, Christoph; McRae, Ken

    2011-01-01

    In some theories of sentence comprehension, linguistically relevant lexical knowledge, such as selectional restrictions, is privileged in terms of the time-course of its access and influence. We examined whether event knowledge computed by combining multiple concepts can rapidly influence language understanding even in the absence of selectional

  14. Alcohol, drugs, and condom use among drug offenders: An event-based analysis

    PubMed Central

    Leigh, Barbara C.; Ames, Susan L.; Stacy, Alan W.

    2008-01-01

    Background Studies of the association between substance use and condom use in specific sexual encounters often do not separate the effects of alcohol and different types of drugs. Because the pharmacological effects and social settings of various substances differ, their effects on unprotected intercourse may vary as well. Goal This study examined the relationship between alcohol and drug use and the use of condoms in sexual encounters with casual partners in a high-risk population of drug offenders Design Participants in court-ordered drug diversion programs (n=536; 26% female) completed a questionnaire in which they reported on the circumstances of their most recent sexual encounter with a casual partner. Results In multivariate logistic models, alcohol use in conjunction with sex was not related to decreased condom use in either men or women. Amphetamines (smoked or injected) were associated with decreased condom use, while cocaine, marijuana, and orally-administered amphetamines were not significantly associated with condom use. Conclusions In this high-risk sample, links between substance use and unprotected sex differ with type of drug used. PMID:17928167

  15. Event-Based Hydrologic Model Calibration using NEXRAD Data in a Southern New Jersey Watershed

    NASA Astrophysics Data System (ADS)

    Seigel, C.; Daraio, J. A.

    2014-12-01

    Proper calibration of hydrologic models requires both reliable observed stream flow and precipitation data. Southern New Jersey has a notable lack of observed precipitation data, in particular, at the event scale; therefore model calibration represents a significant challenge. From a design standpoint this has not been a major concern as hydrologic models have been driven using design storms and are not calibrated. However, the need for research and impact analyses in the face of climate change (changes in extreme precipitation and sea-level rise in particular) and expected population growth in the region requires calibrated models, and reliable observed precipitation data are necessary for model calibration. Several HEC-HMS watershed models were developed and calibrated using NEXRAD data for the upper Maurice River watershed in southern New Jersey, which contains the two growing urban areas of Vineland and Glassboro, to meet three objectives: (1) to validate that NEXRAD data can be effectively utilized in this region, (2) to better understand the roles that spatial variability and scaling play in the use of NEXRAD data within a hydrologic model, and (3) to determine the possible effects of urbanization on stream flow within this watershed. Gridded NEXRAD data were converted to virtual rain gages using the Watershed Modeling System and used as input for HEC-HMS models. Preliminary results indicate that models forced by a spatially coarse distribution (one rain gage for the watershed) of precipitation perform better than models driven by higher resolution precipitation data (14 rain gages for the watershed) for large or extreme events (e.g. hurricanes), and higher resolution precipitation driven models performed better than lower resolution models for smaller events indicating that models should be calibrated from events of the same scale for valid model application.

  16. Event-Based Computation of Motion Flow on a Neuromorphic Analog Neural Platform

    PubMed Central

    Giulioni, Massimiliano; Lagorce, Xavier; Galluppi, Francesco; Benosman, Ryad B.

    2016-01-01

    Estimating the speed and direction of moving objects is a crucial component of agents behaving in a dynamic world. Biological organisms perform this task by means of the neural connections originating from their retinal ganglion cells. In artificial systems the optic flow is usually extracted by comparing activity of two or more frames captured with a vision sensor. Designing artificial motion flow detectors which are as fast, robust, and efficient as the ones found in biological systems is however a challenging task. Inspired by the architecture proposed by Barlow and Levick in 1965 to explain the spiking activity of the direction-selective ganglion cells in the rabbit's retina, we introduce an architecture for robust optical flow extraction with an analog neuromorphic multi-chip system. The task is performed by a feed-forward network of analog integrate-and-fire neurons whose inputs are provided by contrast-sensitive photoreceptors. Computation is supported by the precise time of spike emission, and the extraction of the optical flow is based on time lag in the activation of nearby retinal neurons. Mimicking ganglion cells our neuromorphic detectors encode the amplitude and the direction of the apparent visual motion in their output spiking pattern. Hereby we describe the architectural aspects, discuss its latency, scalability, and robustness properties and demonstrate that a network of mismatched delicate analog elements can reliably extract the optical flow from a simple visual scene. This work shows how precise time of spike emission used as a computational basis, biological inspiration, and neuromorphic systems can be used together for solving specific tasks. PMID:26909015

  17. Sentiment Diffusion of Public Opinions about Hot Events: Based on Complex Network.

    PubMed

    Hao, Xiaoqing; An, Haizhong; Zhang, Lijia; Li, Huajiao; Wei, Guannan

    2015-01-01

    To study the sentiment diffusion of online public opinions about hot events, we collected people's posts through web data mining techniques. We calculated the sentiment value of each post based on a sentiment dictionary. Next, we divided those posts into five different orientations of sentiments: strongly positive (P), weakly positive (p), neutral (o), weakly negative (n), and strongly negative (N). These sentiments are combined into modes through coarse graining. We constructed sentiment mode complex network of online public opinions (SMCOP) with modes as nodes and the conversion relation in chronological order between different types of modes as edges. We calculated the strength, k-plex clique, clustering coefficient and betweenness centrality of the SMCOP. The results show that the strength distribution obeys power law. Most posts' sentiments are weakly positive and neutral, whereas few are strongly negative. There are weakly positive subgroups and neutral subgroups with ppppp and ooooo as the core mode, respectively. Few modes have larger betweenness centrality values and most modes convert to each other with these higher betweenness centrality modes as mediums. Therefore, the relevant person or institutes can take measures to lead people's sentiments regarding online hot events according to the sentiment diffusion mechanism. PMID:26462230

  18. Motion Entropy Feature and Its Applications to Event-Based Segmentation of Sports Video

    NASA Astrophysics Data System (ADS)

    Chen, Chen-Yu; Wang, Jia-Ching; Wang, Jhing-Fa; Hu, Yu-Hen

    2008-12-01

    An entropy-based criterion is proposed to characterize the pattern and intensity of object motion in a video sequence as a function of time. By applying a homoscedastic error model-based time series change point detection algorithm to this motion entropy curve, one is able to segment the corresponding video sequence into individual sections, each consisting of a semantically relevant event. The proposed method is tested on six hours of sports videos including basketball, soccer, and tennis. Excellent experimental results are observed.

  19. The cognitive cost of event-based prospective memory in children.

    PubMed

    Leigh, Janet; Marcovitch, Stuart

    2014-11-01

    Prospective memory is the act of remembering to perform an action in the future, often after the presentation of a cue. However, processes involved in remembering the future intention might hinder performance on activities leading up to and surrounding the event in which an intention must be carried out. The current study was designed to assess whether young children who were asked to engage in prospective memory do so at a cost to current cognitive processing. Participants (4-, 5-, and 6-year-olds) either performed a simple ongoing selection task only (control condition) or performed the selection task with an embedded prospective memory task (experimental condition). Results revealed that children in the experimental condition were slower in the execution of the ongoing task relative to children in the control condition, lending support to the theory that children as young as 4 ears selectively allocate resources in an effort to succeed in multiple tasks. PMID:24853249

  20. A Program Structure for Event-Based Speech Synthesis by Rules within a Flexible Segmental Framework.

    ERIC Educational Resources Information Center

    Hill, David R.

    1978-01-01

    A program structure based on recently developed techniques for operating system simulation has the required flexibility for use as a speech synthesis algorithm research framework. This program makes synthesis possible with less rigid time and frequency-component structure than simpler schemes. It also meets real-time operation and memory-size…

  1. Folk Theorems on the Correspondence between State-Based and Event-Based Systems

    NASA Astrophysics Data System (ADS)

    Reniers, Michel A.; Willemse, Tim A. C.

    Kripke Structures and Labelled Transition Systems are the two most prominent semantic models used in concurrency theory. Both models are commonly believed to be equi-expressive. One can find many ad-hoc embeddings of one of these models into the other. We build upon the seminal work of De Nicola and Vaandrager that firmly established the correspondence between stuttering equivalence in Kripke Structures and divergence-sensitive branching bisimulation in Labelled Transition Systems. We show that their embeddings can also be used for a range of other equivalences of interest, such as strong bisimilarity, simulation equivalence, and trace equivalence. Furthermore, we extend the results by De Nicola and Vaandrager by showing that there are additional translations that allow one to use minimisation techniques in one semantic domain to obtain minimal representatives in the other semantic domain for these equivalences.

  2. Iterative and Event-Based Frameworks for University and School District Technology Professional Development Partnerships

    ERIC Educational Resources Information Center

    Winslow, Joseph; Dickerson, Jeremy; Weaver, Carmen; Josey, Fair

    2016-01-01

    Forming technology partnerships between universities and public schools in an era of competition and economic difficulty is a challenge. However, when these partnerships are formed and sustained, the benefits for both are extremely valuable. For a university instructional technology graduate program and school partnership to be successful, the…

  3. Event-based prediction of stream turbidity using a combined cluster analysis and classification tree approach

    NASA Astrophysics Data System (ADS)

    Mather, Amanda L.; Johnson, Richard L.

    2015-11-01

    Stream turbidity typically increases during streamflow events; however, similar event hydrographs can produce markedly different event turbidity behaviors because many factors influence turbidity in addition to streamflow, including antecedent moisture conditions, season, and supply of turbidity-causing materials. Modeling of sub-hourly turbidity as a function of streamflow shows that event model parameters vary on an event-by-event basis. Here we examine the extent to which stream turbidity can be predicted through the prediction of event model parameters. Using three mid-sized streams from the Mid-Atlantic region of the U.S., we show the model parameter set for each event can be predicted based on the event characteristics (e.g., hydrologic, meteorologic and antecedent moisture conditions) using a combined cluster analysis and classification tree approach. The results suggest that the ratio of beginning event discharge to peak event discharge (an estimate of the event baseflow index), as well as catchment antecedent moisture, are important factors in the prediction of event turbidity. Indicators of antecedent moisture, particularly those derived from antecedent discharge, account for the majority of the splitting nodes in the classification trees for all three streams. For this study, prediction of turbidity during streamflow events is based upon observed data (e.g., measured streamflow, precipitation and air temperature). However, the results also suggest that the methods presented here can, in future work, be used in conjunction with forecasts of streamflow, precipitation and air temperature to forecast stream turbidity.

  4. Probing the possible trigger mechanisms of an equatorial plasma bubble event based on multistation optical data

    NASA Astrophysics Data System (ADS)

    Taori, A.; Parihar, N.; Ghodpage, R.; Dashora, N.; Sripathi, S.; Kherani, E. A.; Patil, P. T.

    2015-10-01

    We analyze an equatorial plasma bubble (EPB) event observed in optical 630 nm image data simultaneously from Gadanki (13.5°N, 79.2°E), Kolhapur (16.8°N, 74.2°E), India. The total electron content data from Gadanki together with the ionosonde data from an equatorial Indian station, Tirunelveli (8.7°N, 77.8°E) confirmed the association of observed EPB event with equatorial spread F (ESF). The optical 630 nm images from a farther low-latitude Indian station Ranchi (23.3°N, 85.3°E) show clear signatures of tilted east-west wave structures propagating toward equator. Further, the upward wave energy noted in mesospheric airglow data was found to be negligible. These data suggest that possibly the off-equatorial tilted east-west structures triggered the observed EPB/ESF event.

  5. Extraction of spatio-temporal information of earthquake event based on semantic technology

    NASA Astrophysics Data System (ADS)

    Fan, Hong; Guo, Dan; Li, Huaiyuan

    2015-12-01

    In this paper a web information extraction method is presented which identifies a variety of thematic events utilizing the event knowledge framework derived from text training, and then further uses the syntactic analysis to extract the event key information. The method which combines the text semantic information and domain knowledge of the event makes the extraction of information people interested more accurate. In this paper, web based earthquake news extraction is taken as an example. The paper firstly briefs the overall approaches, and then details the key algorithm and experiments of seismic events extraction. Finally, this paper conducts accuracy analysis and evaluation experiments which demonstrate that the proposed method is a promising way of hot events mining.

  6. Sentiment Diffusion of Public Opinions about Hot Events: Based on Complex Network

    PubMed Central

    Hao, Xiaoqing; An, Haizhong; Zhang, Lijia; Li, Huajiao; Wei, Guannan

    2015-01-01

    To study the sentiment diffusion of online public opinions about hot events, we collected people’s posts through web data mining techniques. We calculated the sentiment value of each post based on a sentiment dictionary. Next, we divided those posts into five different orientations of sentiments: strongly positive (P), weakly positive (p), neutral (o), weakly negative (n), and strongly negative (N). These sentiments are combined into modes through coarse graining. We constructed sentiment mode complex network of online public opinions (SMCOP) with modes as nodes and the conversion relation in chronological order between different types of modes as edges. We calculated the strength, k-plex clique, clustering coefficient and betweenness centrality of the SMCOP. The results show that the strength distribution obeys power law. Most posts’ sentiments are weakly positive and neutral, whereas few are strongly negative. There are weakly positive subgroups and neutral subgroups with ppppp and ooooo as the core mode, respectively. Few modes have larger betweenness centrality values and most modes convert to each other with these higher betweenness centrality modes as mediums. Therefore, the relevant person or institutes can take measures to lead people’s sentiments regarding online hot events according to the sentiment diffusion mechanism. PMID:26462230

  7. Simulation of event-based landslides and debris flows at watershed level

    NASA Astrophysics Data System (ADS)

    Chiang, Shou-Hao; Chang, Kang-Tsung; Mondini, Alessandro C.; Tsai, Bor-Wen; Chen, Chen-Yu

    2012-02-01

    A coupled model has been developed to simulate, at watershed level, landslides and debris flows induced by a severe typhoon (tropical cyclone) in Taiwan. The model comprises a landslide susceptibility model to predict landslide occurrence, an empirical model to select debris-flow initiation points, and a debris flow model to simulate the transport and deposit of failed materials from the identified source areas. In raster format with a 10 m spatial resolution, the model output includes unstable cells, debris-flow initiation cells, debris-flow velocities, runout paths, and deposition zones. The model was first tested and calibrated in a small area, where the damage by landslides had been investigated and recorded. It was then applied to a watershed, and the simulation results were validated by comparing them with a landslide/debris-flow inventory map prepared from satellite images using a multiple change detection technique. Model test and validation results confirm the usefulness of the model in predicting the number and size of affected areas (landslides and runouts combined), runout path, and volume of runout deposits. It is a common practice in Taiwan to separate landslide and debris-flow inventories and to study debris flows only in select drainage basins. This study suggests that landslide and debris flow should be modeled as a sequential process for efficient watershed management.

  8. Simulation of Event-Based Landslides and Debris Flows at Watershed Level

    NASA Astrophysics Data System (ADS)

    Chiang, S.; Chang, K.

    2011-12-01

    A coupled model has been developed to simulate, at watershed level, landslides and debris flows induced by a severe typhoon (tropical cyclone) in Taiwan. The model comprises a landslide susceptibility model to predict landslide occurrence, an empirical model to select debris-flow initiation points, and a debris flow model to simulate the transport and deposit of failed materials from the identified source areas. In raster format with a 10 m spatial resolution, the model output includes unstable cells, debris-flow initiation cells, debris-flow velocities, runout paths, and deposition zones. The model was first tested and calibrated in a small area, where the damage by landslides and debris flows had been investigated and recorded. It was then applied to a watershed, and the simulation results (Figure 1) were validated by comparing them with a landslide/debris-flow inventory map prepared from satellite images using a multiple change detection technique. Model test and validation results confirm the usefulness of the model in predicting the number and size of affected areas (landslides and runouts combined), runout path, and volume of runout deposits. Details of model results and model limitations will be introduced in the conference presentation. This study suggests that landslide and debris flow should be modeled as a sequential process for efficient watershed management.

  9. Tsunami Source Identification on the 1867 Tsunami Event Based on the Impact Intensity

    NASA Astrophysics Data System (ADS)

    Wu, T. R.

    2014-12-01

    The 1867 Keelung tsunami event has drawn significant attention from people in Taiwan. Not only because the location was very close to the 3 nuclear power plants which are only about 20km away from the Taipei city but also because of the ambiguous on the tsunami sources. This event is unique in terms of many aspects. First, it was documented on many literatures with many languages and with similar descriptions. Second, the tsunami deposit was discovered recently. Based on the literatures, earthquake, 7-meter tsunami height, volcanic smoke, and oceanic smoke were observed. Previous studies concluded that this tsunami was generated by an earthquake with a magnitude around Mw7.0 along the Shanchiao Fault. However, numerical results showed that even a Mw 8.0 earthquake was not able to generate a 7-meter tsunami. Considering the steep bathymetry and intense volcanic activities along the Keelung coast, one reasonable hypothesis is that different types of tsunami sources were existed, such as the submarine landslide or volcanic eruption. In order to confirm this scenario, last year we proposed the Tsunami Reverse Tracing Method (TRTM) to find the possible locations of the tsunami sources. This method helped us ruling out the impossible far-field tsunami sources. However, the near-field sources are still remain unclear. This year, we further developed a new method named 'Impact Intensity Analysis' (IIA). In the IIA method, the study area is divided into a sequence of tsunami sources, and the numerical simulations of each source is conducted by COMCOT (Cornell Multi-grid Coupled Tsunami Model) tsunami model. After that, the resulting wave height from each source to the study site is collected and plotted. This method successfully helped us to identify the impact factor from the near-field potential sources. The IIA result (Fig. 1) shows that the 1867 tsunami event was a multi-source event. A mild tsunami was trigged by a Mw7.0 earthquake, and then followed by the submarine landslide or volcanic events. A near-field submarine landslide and landslide at Mien-Hwa Canyon were the most possible scenarios. As for the volcano scenarios, the volcanic eruption located about 10 km away from Keelung with 2.5x108 m3 disturbed water volume might be a candidate. The detailed scenario results will be presented in the full paper.

  10. Team-Teaching a Current Events-Based Biology Course for Nonmajors

    ERIC Educational Resources Information Center

    Bondos, Sarah E.; Phillips, Dereth

    2008-01-01

    Rice University has created a team-taught interactive biology course for nonmajors with a focus on cutting edge biology in the news--advances in biotechnology, medicine, and science policy, along with the biological principles and methodology upon which these advances are based. The challenges inherent to teaching current topics were minimized by…

  11. Event-Based Monitoring of Sediment Flux Following Removal of Oregon's Marmot Dam

    NASA Astrophysics Data System (ADS)

    Major, J. J.; O'Connor, J. E.; Spicer, K. R.; Bragg, H. M.; Wallick, J. R.; Kittleson, R. L.; Lee, K. K.; Cushman, D.; Piatt, D.; Tanner, D. Q.; Hale, T.; Uhrich, M. A.; Rhode, A.

    2008-12-01

    Breaching of Oregon's Marmot Dam in October 2007 allowed the 80-km-long Sandy River to flow freely from Mount Hood to the Columbia River for the first time in nearly 100 years. When breached, the dam was brimful with sediment. As part of an analysis examining the redistribution of ~730,000 m3 of stored sediment following the dam removal, we measured suspended-sediment load and bedload at sites 10 km upstream and 0.5 to 18 km downstream of the dam before, during and after breaching, and during five subsequent high-water events. Prior to breaching of the dam, suspended-sediment and bedload mass fluxes along the Sandy River both upstream and downstream of the dam were of the order of a few to a few tens of kg/s. Suspended sediment upstream was composed chiefly of sand in contrast to mostly silt and clay passing measurement sites 0.5 and 18 km below the dam. In all reaches bedload consisted chiefly (>90%) of sand. Breaching of the dam released a pulse of turbid water having an instantaneous suspended-sediment flux of 5200 kg/s. The initial sediment pulse consisted predominantly of silt and clay, presumably eroded from thin, fine-grained topset beds at the downstream end of the reservoir. However, the suspended load coarsened rapidly as the Sandy River incised into the stored sand and gravel that filled the former reservoir. Following the initial peak value, median fluxes of sandy suspended sediment 0.5 km below the dam site hovered around several tens to hundreds of kg/s for at least 24 hours, whereas the median suspended- sediment flux remained about 30 kg/s both 10 km upstream and 18 km downstream. Bedload transport also increased following breaching, but its response was slower than for suspended sediment. Bedload flux 0.5 km below the dam site increased from ~1 kg/s before breaching to 60 kg/s by 6 hours and to about 70 kg/s by 18 hours after breaching, in contrast to the steady, low (<10 kg/s) flux of sandy bedload passing upstream and farther downstream before and after breaching. Initially, the near-field bedload consisted predominantly of sand transported in large dunes. Significant gravel transport did not begin until 18 to 20 hours after breaching, in conjunction with rapid bed aggradation and downstream propagation of mid- channel gravel bars. This enhanced sediment transport occurred under a median flow just 30% greater than the river's mean annual flow at Marmot Dam. Within 3 months of breaching, the near-field high-flow-driven bedload flux remained significantly elevated above both upstream and downstream fluxes, but the suspended-sediment flux had declined substantially. Near-field bedload flux was persistently 10 to 100 times greater than that upstream and farther downstream, and remained gravel-rich compared to the sandy bedload passing stations upstream and 18 km distant. In contrast, near-field suspended-sediment concentrations declined approximately logarithmically, and by January 2008 the associated sandy suspended-sediment flux was comparable in both composition and magnitude to the suspended-sediment flux 18 km distant. The newly energetic Sandy River thus rapidly flushed sandy suspended-sediment downstream. Gravel-rich bedload continues to disperse downstream, but has yet to reach distal reaches of the river system. The majority of gravel transported thus far is stored chiefly along the 2-km-long channel reach below the dam site and within the Sandy River gorge 2-8 km downstream from the dam site.

  12. Event-Based Computation of Motion Flow on a Neuromorphic Analog Neural Platform.

    PubMed

    Giulioni, Massimiliano; Lagorce, Xavier; Galluppi, Francesco; Benosman, Ryad B

    2016-01-01

    Estimating the speed and direction of moving objects is a crucial component of agents behaving in a dynamic world. Biological organisms perform this task by means of the neural connections originating from their retinal ganglion cells. In artificial systems the optic flow is usually extracted by comparing activity of two or more frames captured with a vision sensor. Designing artificial motion flow detectors which are as fast, robust, and efficient as the ones found in biological systems is however a challenging task. Inspired by the architecture proposed by Barlow and Levick in 1965 to explain the spiking activity of the direction-selective ganglion cells in the rabbit's retina, we introduce an architecture for robust optical flow extraction with an analog neuromorphic multi-chip system. The task is performed by a feed-forward network of analog integrate-and-fire neurons whose inputs are provided by contrast-sensitive photoreceptors. Computation is supported by the precise time of spike emission, and the extraction of the optical flow is based on time lag in the activation of nearby retinal neurons. Mimicking ganglion cells our neuromorphic detectors encode the amplitude and the direction of the apparent visual motion in their output spiking pattern. Hereby we describe the architectural aspects, discuss its latency, scalability, and robustness properties and demonstrate that a network of mismatched delicate analog elements can reliably extract the optical flow from a simple visual scene. This work shows how precise time of spike emission used as a computational basis, biological inspiration, and neuromorphic systems can be used together for solving specific tasks. PMID:26909015

  13. Event-based rainfall-runoff modelling of the Kelantan River Basin

    NASA Astrophysics Data System (ADS)

    Basarudin, Z.; Adnan, N. A.; Latif, A. R. A.; Tahir, W.; Syafiqah, N.

    2014-02-01

    Flood is one of the most common natural disasters in Malaysia. According to hydrologists there are many causes that contribute to flood events. The two most dominant factors are the meteorology factor (i.e climate change) and change in land use. These two factors contributed to floods in recent decade especially in the monsoonal catchment such as Malaysia. This paper intends to quantify the influence of rainfall during extreme rainfall events on the hydrological model in the Kelantan River catchment. Therefore, two dynamic inputs were used in the study: rainfall and river discharge. The extreme flood events in 2008 and 2004 were compared based on rainfall data for both years. The events were modeled via a semi-distributed HEC-HMS hydrological model. Land use change was not incorporated in the study because the study only tries to quantify rainfall changes during these two events to simulate the discharge and runoff value. Therefore, the land use data representing the year 2004 were used as inputs in the 2008 runoff model. The study managed to demonstrate that rainfall change has a significant impact to determine the peak discharge and runoff depth for the study area.

  14. Transcriptional regulatory analysis reveals PDR3 and GCR1 as regulators of significantly induced genes by 5-hydroxymethylfurfural stress involved in bioethanol conversion for ethanologenic yeast Saccharomyces cerevisiae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    5-Hydroxymethylfurfural (HMF) is one of major inhibitory compounds derived from dehydration of hexoses during biomass degradation using dilute acid hydrolysis. It inhibits yeast growth, reduces enzymatic activities, breaks down DNA, and represses protein and RNA synthesis. We study stress toleranc...

  15. Simulation of the ATIC-2 Silicon Matrix for Protons and Helium GCR Primaries at 0.3, 10, and 25 TeV/Nucleon

    NASA Technical Reports Server (NTRS)

    Watts, J.; Adams, J. H.; Bashindzhagyan, G.; Batkov, K. E.; Chang, J.; Christl, M.; Fazely, A. R.; Ganel, O.; Gunasingha R. M.; Guzik, T. G.

    2005-01-01

    The energy deposition distribution for protons and helium galactic cosmic ray primaries at 0.3, 10, and 25 TeV/nucleon in the ATIC-2 silicon matrix detector are simulated with GEANT4. The GEANT3 geometrical model of ATIC developed by the University of Maryland was combined with a GEANT4 application developed for the Deep Space Test Bed (DSTB) detector package. The new code included relatively minor modifications to completely describe the ATIC materials and a more detailed model of the Silicon Matrix detector. For this analysis all particles were started as a unidirectional beam at a single point near the center of the Silicon Matrix front surface. The point was selected such that each primary passed through at least two of the overlapping silicon pixels.

  16. Event-based surveillance of food- and waterborne diseases in Europe: urgent inquiries (outbreak alerts) during 2008 to 2013.

    PubMed

    Gossner, C M; de Jong, B; Hoebe, C J; Coulombier, D

    2015-01-01

    During 2008 to 2013, 215 outbreak alerts, also known as 'urgent inquiries' (UI), for food- and waterborne diseases were launched in Europe, the majority of them (135; 63%) being related to salmonellosis. For 110 (51%) UI, a potential food vehicle of infection was identified, with vegetables being the most reported category (34;31%). A total of 28% (n = 60) of the outbreaks reported had an international dimension, involving at least two countries (mean: 4; standard deviation: 2; range:2–14). Participating countries posted 2,343 messages(initial posts and replies, excluding updates), with a median of 11 messages per urgent inquiry (range:1–28). Of 60 multicountry UI, 50 involved between two and four countries. The UI allowed early detection of multicountry outbreaks, facilitated the identification of the suspected vehicles and consequently contributed to the timely implementation of control measures. The introduction of an epidemic intelligence information system platform in 2010 has strengthened the role of the Food- and Waterborne Diseases and Zoonoses network in facilitating timely exchange of information between public health authorities of the participating countries. PMID:26132769

  17. The natural oscillation of two types of ENSO events based on analyses of CMIP5 model control runs

    NASA Astrophysics Data System (ADS)

    Xu, Kang; Su, Jingzhi; Zhu, Congwen

    2014-07-01

    The eastern- and central-Pacific El Niño-Southern Oscillation (EP- and CP-ENSO) have been found to be dominant in the tropical Pacific Ocean, and are characterized by interannual and decadal oscillation, respectively. In the present study, we defined the EP- and CP-ENSO modes by singular value decomposition (SVD) between SST and sea level pressure (SLP) anomalous fields. We evaluated the natural features of these two types of ENSO modes as simulated by the pre-industrial control runs of 20 models involved in phase five of the Coupled Model Intercomparison Project (CMIP5). The results suggested that all the models show good skill in simulating the SST and SLP anomaly dipolar structures for the EP-ENSO mode, but only 12 exhibit good performance in simulating the tripolar CP-ENSO modes. Wavelet analysis suggested that the ensemble principal components in these 12 models exhibit an interannual and multi-decadal oscillation related to the EP- and CP-ENSO, respectively. Since there are no changes in external forcing in the pre-industrial control runs, such a result implies that the decadal oscillation of CP-ENSO is possibly a result of natural climate variability rather than external forcing.

  18. Event-based estimation of water budget components using the network of multi-sensor capacitance probes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A time-scale-free approach was developed for estimation of water fluxes at boundaries of monitoring soil profile using water content time series. The approach uses the soil water budget to compute soil water budget components, i.e. surface-water excess (Sw), infiltration less evapotranspiration (I-E...

  19. An event-based vibration control for a two-link flexible robotic arm: Numerical and experimental observations

    NASA Astrophysics Data System (ADS)

    Özer, Abdullah; Eren Semercigil, S.

    2008-06-01

    Flexible robot manipulators have numerous advantages over their rigid counterparts. They have increased payload-to-weight ratio, they run at higher speeds, use less energy and smaller actuators, and they are safer during interaction with their environments. On the other hand, light design combined with external effects result in components which can oscillate with excessive amplitudes. These oscillations cause deviation from the desired path and long idle periods between tasks in order to perform the intended operation safely and accurately. This paper is on an investigation into the effectiveness of a vibration control technique for a two-link flexible robotic arm. Variable stiffness control (VSC) technique is used to control the excessive oscillations. Owing to its dissipative nature, the technique is stable, it is relatively insensitive to significant parameter changes and suitable to be implemented on existing robots. This research considers that the source of the flexibility is either the joints or the links or both. Simulation results of the response of the arm are presented to show the versatility of the proposed control technique. Experiments are performed on a laboratory prototype and the results are presented to test the validity of simulations.

  20. Building a knowledge base of severe adverse drug events based on AERS reporting data using semantic web technologies.

    PubMed

    Jiang, Guoqian; Wang, Liwei; Liu, Hongfang; Solbrig, Harold R; Chute, Christopher G

    2013-01-01

    A semantically coded knowledge base of adverse drug events (ADEs) with severity information is critical for clinical decision support systems and translational research applications. However it remains challenging to measure and identify the severity information of ADEs. The objective of the study is to develop and evaluate a semantic web based approach for building a knowledge base of severe ADEs based on the FDA Adverse Event Reporting System (AERS) reporting data. We utilized a normalized AERS reporting dataset and extracted putative drug-ADE pairs and their associated outcome codes in the domain of cardiac disorders. We validated the drug-ADE associations using ADE datasets from SIDe Effect Resource (SIDER) and the UMLS. We leveraged the Common Terminology Criteria for Adverse Event (CTCAE) grading system and classified the ADEs into the CTCAE in the Web Ontology Language (OWL). We identified and validated 2,444 unique Drug-ADE pairs in the domain of cardiac disorders, of which 760 pairs are in Grade 5, 775 pairs in Grade 4 and 2,196 pairs in Grade 3. PMID:23920604

  1. Interplanetary crew dose estimates for worst case solar particle events based on historical data for the Carrington flare of 1859.

    PubMed

    Stephens, Daniel L; Townsend, Lawrence W; Hoff, Jennifer L

    2005-01-01

    Over the past two decades, hypothetical models of "worst-case" solar particle event (SPE) spectra have been proposed in order to place an upper bound on radiation doses to critical body organs of interplanetary crews on deep space missions. These event spectra are usually formulated using hypothetical extrapolations of space measurements for previous large events. Here we take a different approach. Recently reported analyses of ice core samples indicate that the Carrington flare of 1859 is the largest event observed in the past 500 years. These ice core data yield estimates of the proton fluence for energies greater than 30 MeV, but provide no other spectrum information. Assuming that the proton energy distribution for such an event is similar to that measured for other recent, large events, interplanetary crew doses are estimated for these hypothetical worst case SPE spectra. These estimated doses are life threatening unless substantial shielding is provided. PMID:15835055

  2. Event based recharge assessment from soil moisture monitoring sites under a steep Mediterranean - semi-arid climatic gradient

    NASA Astrophysics Data System (ADS)

    Ries, Fabian; Sauter, Martin; Lange, Jens

    2014-05-01

    The unsaturated soil zone is of fundamental importance for the understanding of temporal and spatial variability of groundwater recharge. This is especially true for the Mediterranean region where a large fraction of long-term groundwater recharge occurs during above-average wet winters. To improve process knowledge, a dense monitoring network consisting of rainfall gauges, meteorological stations and soil moisture plots was installed along a steep climatic gradient in the Jordan Valley region. Ten-minute soil moisture dynamics of two entire years were modelled by Hydrus-1D whose parameters were calibrated with the help of the Shuffled Complex Evolution algorithm. The scrutinized model was applied to four locations with entirely different soil depth and annual rainfall. During high intensity rainfall events, saturation of deep soil layers was observed for several hours. The continuously modelled water balance yielded percolation pulses that depended on rainfall amounts and occurred simultaneously to a cooling of karst groundwater in a nearby groundwater well. Overall, a strong correlation between the magnitude of deep percolation and soil depth was observed. When the model was applied to a 40-year time series of rainfall data, a mean annual percolation fraction of 40% resulted. This value varied by up to 30% between years with similar (average) rainfall but different rainfall distribution. Here the length of dry spells between single recharge events was one important factor. Percolation fraction of exceptional wet years reached up to 69% of rainfall while for very dry years no percolation was modelled at all. A focused view on the unsaturated soil zone in areas with highly variable annual rainfall can provide valuable insights into recharge heterogeneity under Mediterranean and semi-arid climates.

  3. Pre-Processing Effect on the Accuracy of Event-Based Activity Segmentation and Classification through Inertial Sensors

    PubMed Central

    Fida, Benish; Bernabucci, Ivan; Bibbo, Daniele; Conforto, Silvia; Schmid, Maurizio

    2015-01-01

    Inertial sensors are increasingly being used to recognize and classify physical activities in a variety of applications. For monitoring and fitness applications, it is crucial to develop methods able to segment each activity cycle, e.g., a gait cycle, so that the successive classification step may be more accurate. To increase detection accuracy, pre-processing is often used, with a concurrent increase in computational cost. In this paper, the effect of pre-processing operations on the detection and classification of locomotion activities was investigated, to check whether the presence of pre-processing significantly contributes to an increase in accuracy. The pre-processing stages evaluated in this study were inclination correction and de-noising. Level walking, step ascending, descending and running were monitored by using a shank-mounted inertial sensor. Raw and filtered segments, obtained from a modified version of a rule-based gait detection algorithm optimized for sequential processing, were processed to extract time and frequency-based features for physical activity classification through a support vector machine classifier. The proposed method accurately detected >99% gait cycles from raw data and produced >98% accuracy on these segmented gait cycles. Pre-processing did not substantially increase classification accuracy, thus highlighting the possibility of reducing the amount of pre-processing for real-time applications. PMID:26378544

  4. Adverse Drug Event-based Stratification of Tumor Mutations: A Case Study of Breast Cancer Patients Receiving Aromatase Inhibitors

    PubMed Central

    Wang, Chen; Zimmermann, Michael T.; Prodduturi, Naresh; Chute, Christopher G.; Jiang, Guoqian

    2014-01-01

    Adverse drug events (ADEs) are a critical factor for selecting cancer therapy options. The underlying molecular mechanisms of ADEs associated with cancer therapy drugs may overlap with their antineoplastic mechanisms; an aspect of toxicity. In the present study, we develop a novel knowledge-driven approach that provides an ADE-based stratification (ADEStrata) of tumor mutations. We demonstrate clinical utility of the ADEStrata approach through performing a case study of breast invasive carcinoma (BRCA) patients receiving aromatase inhibitors (AI) from The Cancer Genome Atlas (TCGA) (n=212), focusing on the musculoskeletal adverse events (MS-AEs). We prioritized somatic variants in a manner that is guided by MS-AEs codified as 6 Human Phenotype Ontology (HPO) terms. Pathway enrichment and hierarchical clustering of prioritized variants reveals clusters associated with overall survival. We demonstrated that the prediction of per-patient ADE propensity simultaneously identifies high-risk patients experiencing poor outcomes. In conclusion, the ADEStrata approach could produce clinically and biologically meaningful tumor subtypes that are potentially predictive of the drug response to the cancer therapy drugs. PMID:25954427

  5. Explorative research of methods for discrete space/time simulation integrated with the event-based approach and agent concept

    NASA Astrophysics Data System (ADS)

    Zhou, Yuhong; de By, Rolf; Augustijn, Ellen-Wien

    2006-10-01

    Geographic Information Science (GIS) has provided the methodological and technical supports for modeling and simulation in the geographical domain. However, research methods on building complex simulations in which agents behave and interact in discrete time and space are lacking. The existing simulation systems/software are application-oriented and do not provide a theoretical (conceptual) view. The simulation theories and methods that exist do not incorporate spatial issues, which are the key to linking GIS with simulation theory and practice. This paper introduces a method for developing a conceptual theoretical framework for a spatial simulation system which can potentially be integrated with GIS. Firstly, based on classical discrete event simulation and fresh agent technology, a simulation theory is proposed, which is represented by a conceptual simulation model using UML-based visual syntax. In this theoretical framework, spatial issues including spatial setting, spatial constraints, spatial effects and spatial awareness are emphasized. Next, a testing scenario in the microscopic traffic simulation domain is set up to examine the feasibility of the simulation philosophy. Finally, the method is evaluated from the aspects of feasibility, uncertainty and applicability.

  6. An event-based comparison of two types of automated-recording, weighing bucket rain gauges 1890

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A multi-year, multi-gage comparison of two types of automated-recording weighing-bucket raingages was conducted using precipitation data collected at the United States Department of Agriculture, Agricultural Research Service’s Walnut Gulch Experimental Watershed in Southeast Arizona. The compariso...

  7. Event-based prospective memory in patients with Parkinson’s disease: the effect of emotional valence

    PubMed Central

    Mioni, G.; Meligrana, L.; Rendell, P. G.; Bartolomei, L.; Perini, F.; Stablum, F.

    2015-01-01

    The present study investigated the effect of Parkinson’s disease (PD) on prospective memory (PM) tasks by varying the emotional content of the PM actions. Twenty-one older adults with PD and 25 healthy older adults took part in the present study. Participants performed three virtual days in the Virtual Week task. On each virtual day, participants performed actions with positive, negative or neutral content. Immediately following each virtual day, participants completed a recognition task to assess their retrospective memory for the various PM tasks. PD patients were less accurate than the control group at both PM accuracy and recognition task accuracy. The effect of emotional valence was also evident, indicating that all participants were more accurate on positive PM tasks than both negative and neutral. This study confirmed PM impairment in PD patients and extended previous research showing how positive emotional stimuli can influence PM performance. PMID:26257636

  8. Event-based quantification of emerging pollutant removal for an open stormwater retention basin - loads, efficiency and importance of uncertainties.

    PubMed

    Sébastian, C; Becouze-Lareure, C; Lipeme Kouyi, G; Barraud, S

    2015-04-01

    Up to now, emerging contaminants have not been further-studied in in-situ stormwater best management practices and especially in detention basins. In this article, the efficiency of a dry stormwater detention basin was investigated regarding the removal of 7 alkylphenols and alkylphenol ethoxylates, 9 polybrominated diphenyl ethers, 45 pesticides and bisphenol A. Concentrations of contaminants were obtained by chemical analysis on dissolved and particulate phase distinctly. The removal efficiency was assessed on total, dissolved and particulate phase accounting for the global chain of uncertainty with a 95% confidence interval. Results showed that pesticides (rather hydrophilic) are not trapped in the detention basin but are released contrarily to B209 which is mostly in particulate phase. Alkylphenols and alkylphenol ethoxylates are present in both phases and the efficiency is storm event-dependent. Uncertainty consideration in efficiency determination revealed efficiency data, usually presented by raw values are not relevant to conclude on the performance of a detention basin. In this case study, efficiency data with a 95% confidence interval indicate that only 35%, 50% and 41% of campaigns showed an impact (in trapping or releasing) of the detention basin on alkylphenols and ethoxylates, polybrominated diphenyl ethers and pesticides respectively. PMID:25683631

  9. Robotic goalie with 3 ms reaction time at 4% CPU load using event-based dynamic vision sensor.

    PubMed

    Delbruck, Tobi; Lang, Manuel

    2013-01-01

    Conventional vision-based robotic systems that must operate quickly require high video frame rates and consequently high computational costs. Visual response latencies are lower-bound by the frame period, e.g., 20 ms for 50 Hz frame rate. This paper shows how an asynchronous neuromorphic dynamic vision sensor (DVS) silicon retina is used to build a fast self-calibrating robotic goalie, which offers high update rates and low latency at low CPU load. Independent and asynchronous per pixel illumination change events from the DVS signify moving objects and are used in software to track multiple balls. Motor actions to block the most "threatening" ball are based on measured ball positions and velocities. The goalie also sees its single-axis goalie arm and calibrates the motor output map during idle periods so that it can plan open-loop arm movements to desired visual locations. Blocking capability is about 80% for balls shot from 1 m from the goal even with the fastest-shots, and approaches 100% accuracy when the ball does not beat the limits of the servo motor to move the arm to the necessary position in time. Running with standard USB buses under a standard preemptive multitasking operating system (Windows), the goalie robot achieves median update rates of 550 Hz, with latencies of 2.2 ± 2 ms from ball movement to motor command at a peak CPU load of less than 4%. Practical observations and measurements of USB device latency are provided. PMID:24311999

  10. Robotic goalie with 3 ms reaction time at 4% CPU load using event-based dynamic vision sensor

    PubMed Central

    Delbruck, Tobi; Lang, Manuel

    2013-01-01

    Conventional vision-based robotic systems that must operate quickly require high video frame rates and consequently high computational costs. Visual response latencies are lower-bound by the frame period, e.g., 20 ms for 50 Hz frame rate. This paper shows how an asynchronous neuromorphic dynamic vision sensor (DVS) silicon retina is used to build a fast self-calibrating robotic goalie, which offers high update rates and low latency at low CPU load. Independent and asynchronous per pixel illumination change events from the DVS signify moving objects and are used in software to track multiple balls. Motor actions to block the most “threatening” ball are based on measured ball positions and velocities. The goalie also sees its single-axis goalie arm and calibrates the motor output map during idle periods so that it can plan open-loop arm movements to desired visual locations. Blocking capability is about 80% for balls shot from 1 m from the goal even with the fastest-shots, and approaches 100% accuracy when the ball does not beat the limits of the servo motor to move the arm to the necessary position in time. Running with standard USB buses under a standard preemptive multitasking operating system (Windows), the goalie robot achieves median update rates of 550 Hz, with latencies of 2.2 ± 2 ms from ball movement to motor command at a peak CPU load of less than 4%. Practical observations and measurements of USB device latency are provided1. PMID:24311999

  11. Pre-Processing Effect on the Accuracy of Event-Based Activity Segmentation and Classification through Inertial Sensors.

    PubMed

    Fida, Benish; Bernabucci, Ivan; Bibbo, Daniele; Conforto, Silvia; Schmid, Maurizio

    2015-01-01

    Inertial sensors are increasingly being used to recognize and classify physical activities in a variety of applications. For monitoring and fitness applications, it is crucial to develop methods able to segment each activity cycle, e.g., a gait cycle, so that the successive classification step may be more accurate. To increase detection accuracy, pre-processing is often used, with a concurrent increase in computational cost. In this paper, the effect of pre-processing operations on the detection and classification of locomotion activities was investigated, to check whether the presence of pre-processing significantly contributes to an increase in accuracy. The pre-processing stages evaluated in this study were inclination correction and de-noising. Level walking, step ascending, descending and running were monitored by using a shank-mounted inertial sensor. Raw and filtered segments, obtained from a modified version of a rule-based gait detection algorithm optimized for sequential processing, were processed to extract time and frequency-based features for physical activity classification through a support vector machine classifier. The proposed method accurately detected >99% gait cycles from raw data and produced >98% accuracy on these segmented gait cycles. Pre-processing did not substantially increase classification accuracy, thus highlighting the possibility of reducing the amount of pre-processing for real-time applications. PMID:26378544

  12. Evaluation of Event-Based Algorithms for Optical Flow with Ground-Truth from Inertial Measurement Sensor

    PubMed Central

    Rueckauer, Bodo; Delbruck, Tobi

    2016-01-01

    In this study we compare nine optical flow algorithms that locally measure the flow normal to edges according to accuracy and computation cost. In contrast to conventional, frame-based motion flow algorithms, our open-source implementations compute optical flow based on address-events from a neuromorphic Dynamic Vision Sensor (DVS). For this benchmarking we created a dataset of two synthesized and three real samples recorded from a 240 × 180 pixel Dynamic and Active-pixel Vision Sensor (DAVIS). This dataset contains events from the DVS as well as conventional frames to support testing state-of-the-art frame-based methods. We introduce a new source for the ground truth: In the special case that the perceived motion stems solely from a rotation of the vision sensor around its three camera axes, the true optical flow can be estimated using gyro data from the inertial measurement unit integrated with the DAVIS camera. This provides a ground-truth to which we can compare algorithms that measure optical flow by means of motion cues. An analysis of error sources led to the use of a refractory period, more accurate numerical derivatives and a Savitzky-Golay filter to achieve significant improvements in accuracy. Our pure Java implementations of two recently published algorithms reduce computational cost by up to 29% compared to the original implementations. Two of the algorithms introduced in this paper further speed up processing by a factor of 10 compared with the original implementations, at equal or better accuracy. On a desktop PC, they run in real-time on dense natural input recorded by a DAVIS camera. PMID:27199639

  13. Controls of event-based pesticide leaching in natural soils: A systematic study based on replicated field scale irrigation experiments

    NASA Astrophysics Data System (ADS)

    Klaus, Julian; Zehe, Erwin; Elsner, Martin; Palm, Juliane; Schneider, Dorothee; Schröder, Boris; Steinbeiss, Sibylle; van Schaik, Loes; West, Stephanie

    2014-05-01

    Tile drains strongly influence the water cycle in agricultural catchment in terms of water quantity and quality. The connectivity of preferential flow to tile drains can create shortcuts for rapid transport of solutes into surface waters. The leaching of pesticides can be linked to a set of main factors including, rainfall characteristics, soil moisture, chemical properties of the pesticides, soil properties, and preferential flow paths. The connectivity of the macropore system to the tile drain is crucial for pesticide leaching. Concurring influences of the main factors, threshold responses and the role of flow paths are still poorly understood. The objective of this study is to investigate these influences by a replica series of three irrigation experiments on a tile drain field site using natural and artificial tracers together with applied pesticides. We found a clear threshold behavior in the initialization of pesticide transport that was different between the replica experiments. Pre-event soil water contributed significantly to the tile drain flow, and creates a flow path for stored pesticides from the soil matrix to the tile drain. This threshold is controlled by antecedent soil moisture and precipitation characteristics, and the interaction between the soil matrix and preferential flow system. Fast transport of pesticides without retardation and the remobilization could be attributed to this threshold and the interaction between the soil matrix and the preferential flow system. Thus, understanding of the detailed preferential flow processes clearly enhances the understanding of pesticide leaching on event and long term scale, and can further improve risk assessment and modeling approaches.

  14. Integrated Data Products to Forecast, Mitigate, and Educate for Natural Hazard Events Based on Recent and Historical Observations

    NASA Astrophysics Data System (ADS)

    McCullough, H. L.; Dunbar, P. K.; Varner, J. D.

    2011-12-01

    Immediately following a damaging or fatal natural hazard event there is interest to access authoritative data and information. The National Geophysical Data Center (NGDC) maintains and archives a comprehensive collection of natural hazards data. The NGDC global historic event database includes all tsunami events, regardless of intensity, as well as earthquakes and volcanic eruptions that caused fatalities, moderate damage, or generated a tsunami. Examining the past record provides clues to what might happen in the future. NGDC also archives tide gauge data from stations operated by the NOAA/NOS Center for Operational Oceanographic Products and Services and the NOAA Tsunami Warning Centers. In addition to the tide gauge data, NGDC preserves deep-ocean water-level, 15-second sampled data as collected by the Deep-ocean Assessment and Reporting of Tsunami (DART) buoys. Water-level data provide evidence of sea-level fluctuation and possible inundation events. NGDC houses an extensive collection of geologic hazards photographs available online as digital images. Visual media provide invaluable pre- and post-event data for natural hazards. Images can be used to illustrate inundation and possible damage or effects. These images are organized by event or hazard type (earthquake, volcano, tsunami, landslide, etc.), along with description and location. They may be viewed via interactive online maps and are integrated with historic event details. The planning required to achieve collection and dissemination of hazard event data is extensive. After a damaging or fatal event, NGDC begins to collect and integrate data and information from many people and organizations into the hazards databases. Sources of data include the U.S. NOAA Tsunami Warning Centers, the U.S. Geological Survey, the U.S. NOAA National Data Buoy Center, the UNESCO Intergovernmental Oceanographic Commission (IOC), Smithsonian Institution's Global Volcanism Program, news organizations, etc. NGDC then works to promptly distribute data and information for the appropriate audience. For example, when a major tsunami occurs, all of the related tsunami data are combined into one timely resource. NGDC posts a publicly accessible online report which includes: 1) event summary; 2) eyewitness and instrumental recordings from preliminary field surveys; 3) regional historical observations including similar past events and effects; 4) observed water heights and calculated tsunami travel times; and 5) near-field effects. This report is regularly updated to incorporate the most recent news and observations. Providing timely access to authoritative data and information ultimately benefits researchers, state officials, the media and the public.

  15. Medical mitigation strategies for acute radiation exposure during spaceflight.

    PubMed

    Epelman, Slava; Hamilton, Douglas R

    2006-02-01

    The United States Government has recently refocused their space program on manned missions to the Moon by 2018 and later to Mars. While there are many potential risks associated with exploration-class missions, one of the most serious and unpredictable is the effect of acute space radiation exposure, and the space program must make every reasonable effort to mitigate this risk. The two cosmic sources of radiation that could impact a mission outside the Earth's magnetic field are solar particle events (SPE) and galactic cosmic radiation (GCR). Either can cause acute and chronic medical illness. Numerous researchers are currently examining the ability of GCR exposure to induce the development of genetic changes that lead to malignancies and other delayed effects. However, relatively little has been published on the medical management of an acute SPE event and the potential impact on the mission and crew. This review paper will provide the readers with medical management options for an acute radiation event based on recommendations from the Department of Homeland Security (DHS), Centers for Disease Control (CDC), and evidence-based critical analysis of the scientific literature. It is the goal of this paper to stimulate debate regarding the definition of safety parameters for exploration-class missions to determine the level of medical care necessary to provide for the crew that will undertake such missions. PMID:16491581

  16. Executive and Theory-of-Mind Contributions to Event-Based Prospective Memory in Children: Exploring the Self-Projection Hypothesis

    ERIC Educational Resources Information Center

    Ford, Ruth M.; Driscoll, Timothy; Shum, David; Macaulay, Catrin E.

    2012-01-01

    In two studies, 4- to 6-year-olds were asked to name pictures of animals for the benefit of a watching hand puppet (the ongoing task) but to refrain from naming and to remove from view any pictures of dogs (the prospective memory [PM] task). Children also completed assessments of verbal ability, cognitive inhibition, working memory, and…

  17. Reconstruction of flood events based on documentary data and transnational flood risk analysis of the Upper Rhine and its French and German tributaries since AD 1480

    NASA Astrophysics Data System (ADS)

    Himmelsbach, I.; Glaser, R.; Schoenbein, J.; Riemann, D.; Martin, B.

    2015-10-01

    This paper presents the long-term analysis of flood occurrence along the southern part of the Upper Rhine River system and of 14 of its tributaries in France and Germany covering the period starting from 1480 BC. Special focus is given on the temporal and spatial variations of flood events and their underlying meteorological causes over time. Examples are presented of how long-term information about flood events and knowledge about the historical aspect of flood protection in a given area can help to improve the understanding of risk analysis and therefor transnational risk management. Within this context, special focus is given to flood vulnerability while comparing selected historical and modern extreme events, establishing a common evaluation scheme. The transnational aspect becomes especially evident analyzing the tributaries: on this scale, flood protection developed impressively different on the French and German sides. We argue that comparing high technological standards of flood protection, which were initiated by the dukes of Baden on the German side starting in the early 19th century, misled people to the common belief that the mechanical means of flood protection like dams and barrages can guarantee the security from floods and their impacts. This lead to widespread settlements and the establishment of infrastructure as well as modern industries in potentially unsafe areas until today. The legal status in Alsace on the French side of the Rhine did not allow for continuous flood protection measurements, leading to a constant - and probably at last annoying - reminder that the floodplains are a potentially unsafe place to be. From a modern perspective of flood risk management, this leads to a significant lower aggregation of value in the floodplains of the small rivers in Alsace compared to those on the Baden side - an interesting fact - especially if the modern European Flood directive is taken into account.

  18. Executive and theory-of-mind contributions to event-based prospective memory in children: exploring the self-projection hypothesis.

    PubMed

    Ford, Ruth M; Driscoll, Timothy; Shum, David; Macaulay, Catrin E

    2012-03-01

    In two studies, 4- to 6-year-olds were asked to name pictures of animals for the benefit of a watching hand puppet (the ongoing task) but to refrain from naming and to remove from view any pictures of dogs (the prospective memory [PM] task). Children also completed assessments of verbal ability, cognitive inhibition, working memory, and false-belief understanding (both studies), empathy (Study 1 only), and performance on false-sign tests that matched the false-belief tests in narrative content and structure (Study 2 only). Both studies found that inhibition and false-belief performance made unique contributions to the variance in PM, although in Study 1 the influence of inhibition was evident only when children needed to withhold naming. Study 2 further demonstrated that false-belief performance was the only reliable predictor of whether children remembered to return to the researcher an object that had been loaned to them prior to the picture-naming game. Both experiments uncovered moderate relations between PM and chronological age, but such relations were rarely significant after taking account of cognitive ability. We consider the implications of the findings for (a) current views regarding frontal/executive contributions to PM development and (b) the suggestion that the same brain network underlies various forms of mental self-projection, including envisioning the future and understanding the minds of other people. PMID:22169353

  19. High Temporal Frequency Biophysical and Structural Vegetation Information from Multiple Remote Sensing Sensors can Support Modelling of Event Based Hillslope Erosion in Queensland

    NASA Astrophysics Data System (ADS)

    Schoettker, B.; Searle, R.; Schmidt, M.; Phinn, S.

    2012-07-01

    This study demonstrates the potential applicability of high temporal frequency information on the biophysical condition of the vegetation from a time series of the global Moderate Resolution Imaging Spectroradiometer (MODIS) Fraction of Photosynthetically Active Radiation absorbed by vegetation (FPAR) from 2000 to 2006 (collection 4; 8-day composites in 1 km spatial resolution) to improve modelling of soil loss in a tropical, semi-arid catchment in Queensland. Combining the biophysical information from the MODIS FPAR with structural vegetation information from the Geoscience Laser Altimeter System on the Ice, Cloud, and land Elevation Satellite (ICESat) for six vegetation structural categories identified from a Landsat Thematic Mapper 5 (TM) and Enhanced Thematic Mapper 7 (ETM+) woody foliage projective cover product representing floristically and structurally homogeneous areas, dynamic vegetative cover factor (vCf) estimates were calculated. The dynamic vCf were determined in accordance with standard calculation methods used in erosion models worldwide. Time series of dynamic vCf were integrated into a regionally improved version of the Universal Soil Loss Equation (USLE) to predict daily soil losses for the study area. Resulting time series of daily soil loss predictions averaged over the study area coincided well with measures of total suspended solids (TSS) (mg/l) at a gauge at the outlet of the catchment for three wet seasons (R2 of 0.96 for a TSS-event). By integrating the dynamic vCf into modified USLE, the strength of the dependence of daily soil loss predictions to the only other dynamic factor in the equation - daily rainfall erosivity - was reduced.

  20. Executive and Theory-of-Mind Contributions to Event-Based Prospective Memory in Children: Exploring the Self-Projection Hypothesis

    ERIC Educational Resources Information Center

    Ford, Ruth M.; Driscoll, Timothy; Shum, David; Macaulay, Catrin E.

    2012-01-01

    In two studies, 4- to 6-year-olds were asked to name pictures of animals for the benefit of a watching hand puppet (the ongoing task) but to refrain from naming and to remove from view any pictures of dogs (the prospective memory [PM] task). Children also completed assessments of verbal ability, cognitive inhibition, working memory, and

  1. Precipitation induced stream flow: An event based chemical andisotopic study of a small stream in the Great Plains region of theUSA

    SciTech Connect

    Machavaram, Madhav V.; Whittemore, Donald O.; Conrad, Mark E.; Miller, Norman L.

    2005-03-22

    A small stream in the Great Plains of USA was sampled tounderstand the streamflow components following intense precipitation andthe influence of water storage structures in the drainage basin.Precipitation, stream, ponds, ground-water and soil moisture were sampledfor determination of isotopic (D, 18O) and chemical (Cl, SO4) compositionbefore and after two intense rain events. Following the first stormevent, flow at the downstream locations was generated primarily throughshallow subsurface flow and runoff whereas in the headwaters region --where a pond is located in the stream channel -- shallow ground-water andpond outflow contributed to the flow. The distinct isotopic signatures ofprecipitation and the evaporated pond water allowed separation of theevent water from the other sources that contributed to the flow.Similarly, variations in the Cl and SO4 concentrations helped identifythe relative contributions of ground-water and soil moisture to thestream flow. The relationship between deuterium excess and Cl or SO4content reveals that the early contributions from a rain event tostreamflow depend upon the antecedent climatic conditions and theposition along the stream channel within the watershed. The design ofthis study, in which data from several locations within a watershed werecollected, shows that in small streams changes in relative contributionsfrom ground water and soil moisture complicate hydrograph separation,with surface-water bodies providing additional complexity. It alsodemonstrates the usefulness of combined chemical and isotopic methods inhydrologic investigations, especially the utility of the deuterium excessparameter in quantifying the relative contributions of various sourcecomponents to the stream flow.

  2. A Hydrologic Event-based Evaluation of Water Quality Trends in Goodwater Creek Experimental Watershed, Missouri USA: Implications for Watershed Monitoring Strategies and Objective Setting

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Continued public support for U.S. tax-payer funded programs aimed at reducing agricultural non-point source pollutants depends on clear demonstrations of water quality improvements. However, little is currently known about past watershed-scale effects due to implementation of structural best manage...

  3. Precipitation induced stream flow: An event based chemical and isotopic study of a small stream in the Great Plains region of the USA

    USGS Publications Warehouse

    Machavaram, M.V.; Whittemore, D.O.; Conrad, M.E.; Miller, N.L.

    2006-01-01

    A small stream in the Great Plains of USA was sampled to understand the streamflow components following intense precipitation and the influence of water storage structures in the drainage basin. Precipitation, stream, ponds, ground-water and soil moisture were sampled for determination of isotopic (D, 18O) and chemical (Cl, SO4) composition before and after two intense rain events. Following the first storm event, flow at the downstream locations was generated primarily through shallow subsurface flow and runoff whereas in the headwaters region - where a pond is located in the stream channel - shallow ground-water and pond outflow contributed to the flow. The distinct isotopic signatures of precipitation and the evaporated pond water allowed separation of the event water from the other sources that contributed to the flow. Similarly, variations in the Cl and SO4 concentrations helped identify the relative contributions of ground-water and soil moisture to the streamflow. The relationship between deuterium excess and Cl or SO4 content reveals that the early contributions from a rain event to streamflow depend upon the antecedent climatic conditions and the position along the stream channel within the watershed. The design of this study, in which data from several locations within a watershed were collected, shows that in small streams changes in relative contributions from ground water and soil moisture complicate hydrograph separation, with surface-water bodies providing additional complexity. It also demonstrates the usefulness of combined chemical and isotopic methods in hydrologic investigations, especially the utility of the deuterium excess parameter in quantifying the relative contributions of various source components to the stream flow. ?? 2006 Elsevier B.V. All rights reserved.

  4. Global environmental change: The role of space in understanding earth; Proceedings of the Twenty-seventh Goddard Memorial Symposium, Washington, DC, Mar. 8-10, 1989

    SciTech Connect

    Johnson, R.G.

    1990-01-01

    The present conference on environmental change-related earth remote sensing from space discusses NASA goals and plans for global change research (GCR), the NOAA's role in GCR, the International Space Year's Mission to Planet Earth, biological systems' roles in global change, ocean sciences and global change, and solid-earth and hydrological sciences in the GCR context. Also discussed are passive microwave sensors, active optical sensor technology, passive electrooptic sensors for GCR, and UV remote sensing technology.

  5. Galactic Cosmic Ray Simulator at the NASA Space Radiation Laboratory

    NASA Technical Reports Server (NTRS)

    Norbury, John W.; Slaba, Tony C.; Rusek, Adam

    2015-01-01

    The external Galactic Cosmic Ray (GCR) spectrum is significantly modified when it passes through spacecraft shielding and astronauts. One approach for simulating the GCR space radiation environment is to attempt to reproduce the unmodified, external GCR spectrum at a ground based accelerator. A possibly better approach would use the modified, shielded tissue spectrum, to select accelerator beams impinging on biological targets. NASA plans for implementation of a GCR simulator at the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory will be discussed.

  6. International Collaboration for Galactic Cosmic Ray Simulation at the NASA Space Radiation Laboratory

    NASA Technical Reports Server (NTRS)

    Norbury, John W.; Slaba, Tony C.; Rusek, Adam; Durante, Marco; Reitz, Guenther

    2015-01-01

    An international collaboration on Galactic Cosmic Ray (GCR) simulation is being formed to make recommendations on how to best simulate the GCR spectrum at ground based accelerators. The external GCR spectrum is significantly modified when it passes through spacecraft shielding and astronauts. One approach for simulating the GCR space radiation environment at ground based accelerators would use the modified spectrum, rather than the external spectrum, in the accelerator beams impinging on biological targets. Two recent workshops have studied such GCR simulation. The first workshop was held at NASA Langley Research Center in October 2014. The second workshop was held at the NASA Space Radiation Investigators' workshop in Galveston, Texas in January 2015. The anticipated outcome of these and other studies may be a report or journal article, written by an international collaboration, making accelerator beam recommendations for GCR simulation. This poster describes the status of GCR simulation at the NASA Space Radiation Laboratory and encourages others to join the collaboration.

  7. Projecting Event-Based Analysis Dates in Clinical Trials: An Illustration Based on the International Duration Evaluation of Adjuvant Chemotherapy (IDEA) Collaboration. Projecting analysis dates for the IDEA collaboration

    PubMed Central

    Renfro, Lindsay A.; Grothey, Axel M.; Paul, James; Floriani, Irene; Bonnetain, Franck; Niedzwiecki, Donna; Yamanaka, Takeharu; Souglakos, Ioannis; Yothers, Greg; Sargent, Daniel J.

    2015-01-01

    Purpose Clinical trials are expensive and lengthy, where success of a given trial depends on observing a prospectively defined number of patient events required to answer the clinical question. The point at which this analysis time occurs depends on both patient accrual and primary event rates, which typically vary throughout the trial's duration. We demonstrate real-time analysis date projections using data from a collection of six clinical trials that are part of the IDEA collaboration, an international preplanned pooling of data from six trials testing the duration of adjuvant chemotherapy in stage III colon cancer, and we additionally consider the hypothetical impact of one trial's early termination of follow-up. Patients and Methods In the absence of outcome data from IDEA, monthly accrual rates for each of the six IDEA trials were used to project subsequent trial-specific accrual, while historical data from similar Adjuvant Colon Cancer Endpoints (ACCENT) Group trials were used to construct a parametric model for IDEA's primary endpoint, disease-free survival, under the same treatment regimen. With this information and using the planned total accrual from each IDEA trial protocol, individual patient accrual and event dates were simulated and the overall IDEA interim and final analysis times projected. Projections were then compared with actual (previously undisclosed) trial-specific event totals at a recent census time for validation. The change in projected final analysis date assuming early termination of follow-up for one IDEA trial was also calculated. Results Trial-specific predicted event totals were close to the actual number of events per trial for the recent census date at which the number of events per trial was known, with the overall IDEA projected number of events only off by eight patients. Potential early termination of follow-up by one IDEA trial was estimated to postpone the overall IDEA final analysis date by 9 months. Conclusions Real-time projection of the final analysis time during a trial, or the overall analysis time during a trial collaborative such as IDEA, has practical implications for trial feasibility when these projections are translated into additional time and resources required.

  8. Aromatase inhibitors alone or sequentially combined with tamoxifen in postmenopausal early breast cancer compared with tamoxifen or placebo - Meta-analyses on efficacy and adverse events based on randomized clinical trials.

    PubMed

    Rydén, Lisa; Heibert Arnlind, Marianne; Vitols, Sigurd; Höistad, Malin; Ahlgren, Johan

    2016-04-01

    Tamoxifen (TAM) and aromatase inhibitors (AI) are adjuvant therapy options for postmenopausal women with estrogen receptor positive (ER+) breast cancer. This systematic review of seven randomized controlled studies comparing TAM and AI, and one study comparing extended therapy with an AI with placebo after about 5 years of tamoxifen, aims to assess long-term clinical efficacy and adverse events. The literature review was performed according to the principles of the Cochrane Collaboration. The search included common databases up to 2013-01-14. Studies of high or moderate quality were used for grading of evidence. Revman™ software was utilized for meta-analyses of published data. Disease free survival (DFS) and overall survival (OS) were improved with AI monotherapy compared to TAM with high and moderate quality of evidence respectively. Sequenced therapy with AI → TAM (or vice versa) improved DFS compared with TAM with moderate quality of evidence, but did not improve OS (low quality of evidence). However, if only studies on sequenced AI therapy with randomization before endocrine therapy were considered, no improvement of DFS could be found. Fractures are more frequently associated with AI whereas the risk of endometrial cancer and venous thromboembolism are higher with TAM. For cardiovascular events no difference was found between AI (mono- or sequenced therapy) and TAM, whereas sequenced therapy compared with AI had lower risk of cardiovascular events (moderate level of evidence). AIs are superior to TAM as adjuvant hormonal therapy for postmenopausal ER-positive breast cancer. TAM can be considered for individual patients due to the different toxicity profile compared with AI. Cardiovascular events related to AI treatment deserve further attention. PMID:27017249

  9. Do Plants Contain G Protein-Coupled Receptors?1[C][W][OPEN

    PubMed Central

    Taddese, Bruck; Upton, Graham J.G.; Bailey, Gregory R.; Jordan, Siân R.D.; Abdulla, Nuradin Y.; Reeves, Philip J.; Reynolds, Christopher A.

    2014-01-01

    Whether G protein-coupled receptors (GPCRs) exist in plants is a fundamental biological question. Interest in deorphanizing new GPCRs arises because of their importance in signaling. Within plants, this is controversial, as genome analysis has identified 56 putative GPCRs, including G protein-coupled receptor1 (GCR1), which is reportedly a remote homolog to class A, B, and E GPCRs. Of these, GCR2 is not a GPCR; more recently, it has been proposed that none are, not even GCR1. We have addressed this disparity between genome analysis and biological evidence through a structural bioinformatics study, involving fold recognition methods, from which only GCR1 emerges as a strong candidate. To further probe GCR1, we have developed a novel helix-alignment method, which has been benchmarked against the class A-class B-class F GPCR alignments. In addition, we have presented a mutually consistent set of alignments of GCR1 homologs to class A, class B, and class F GPCRs and shown that GCR1 is closer to class A and/or class B GPCRs than class A, class B, or class F GPCRs are to each other. To further probe GCR1, we have aligned transmembrane helix 3 of GCR1 to each of the six GPCR classes. Variability comparisons provide additional evidence that GCR1 homologs have the GPCR fold. From the alignments and a GCR1 comparative model, we have identified motifs that are common to GCR1, class A, B, and E GPCRs. We discuss the possibilities that emerge from this controversial evidence that GCR1 has a GPCR fold. PMID:24246381

  10. Low Clouds and Cosmic Rays: Possible Reasons for Correlation Changes

    NASA Astrophysics Data System (ADS)

    Veretenenko, S. V.; Ogurtsov, M. G.

    2015-03-01

    In this work we investigated the nature of correlations between low cloud cover anomalies (LCA) and galactic cosmic ray (GCR) variations detected on the decadal time scale, as well as possible reasons for the violation of these correlations in the early 2000s. It was shown that the link between cloud cover at middle latitudes and GCR fluxes is not direct, but it is realized through GCR influence on the development of extratropical baric systems (cyclones and troughs) which form cloud field. As the sign of GCR effects on the troposphere dynamics seems to depend on the strength of the stratospheric polar vortex, a possible reason for the violation of a positive correlation between LCA and GCR fluxes in the early 2000s may be the change of the vortex state which resulted in the reversal of GCR effects on extratropical cyclone development.

  11. Galactic cosmic ray currents and magnetic field irregularity degree in high-speed solar wind streams

    NASA Technical Reports Server (NTRS)

    Kuzmin, A. I.; Samsonov, I. S.; Samsonova, Z. N.

    1985-01-01

    Currents of galactic cosmic rays (GCR) obtained by global survey method are analyzed. The cases of almost total disappearance of GCR currents are compared with the results of direct measurements of the solar wind parameters. The conclusion is made on a restricted application of the convective-diffusive mechanism of the GCR modulation by the solar wind during the occurrence of stationary and regular magnetic fields in the interplanetary medium.

  12. Galactic cosmic ray transport methods and radiation quality issues

    NASA Technical Reports Server (NTRS)

    Townsend, L. W.; Wilson, J. W.; Cucinotta, F. A.; Shinn, J. L.

    1992-01-01

    An overview of galactic cosmic ray (GCR) interaction and transport methods, as implemented in the Langley Research Center GCR transport code, is presented. Representative results for solar minimum, exo-magnetospheric GCR dose equivalents in water are presented on a component by component basis for various thicknesses of aluminum shielding. The impact of proposed changes to the currently used quality factors on exposure estimates and shielding requirements are quantified. Using the cellular track model of Katz, estimates of relative biological effectiveness (RBE) for the mixed GCR radiation fields are also made.

  13. [Study of morphological types of nephrotic glomerulonephritis and the number of glucocorticoid receptors of lymphocytes for prognosis of the effectiveness of glucocorticoid therapy].

    PubMed

    Sasu, B I; Mukhin, N A; Serov, V V; Varshavskiĭ, V A

    1984-01-01

    The study of the glucocortocoid receptors (GCR) level of blood lymphocytes in 31 patients with glomerulonephritis (GN) of the nephrotic type revealed the lack of a clear parallelism between the morphological type of GN and GCR level. A relatively low GCR level correlates with the resistance of nephrotic GN patients regardless of the GN morphological type. The patients with a relatively low GCR level did not respond to the glucocorticoid (GC) therapy even if they had morphological types of nephrotic GN considered to be "favourable" for this therapy (mesangio-proliferative and membranous GN). It is stated that the GC therapy for such patients is not justified. PMID:6383286

  14. An inhibitor of viral RNA replication is encoded by a plant resistance gene.

    PubMed

    Ishibashi, Kazuhiro; Masuda, Kiyoshi; Naito, Satoshi; Meshi, Tetsuo; Ishikawa, Masayuki

    2007-08-21

    The tomato Tm-1 gene confers resistance to tomato mosaic virus (ToMV). Here, we report that the extracts of Tm-1 tomato cells (GCR237) have properties that inhibit the in vitro RNA replication of WT ToMV more strongly than that of the Tm-1-resistance-breaking mutant of ToMV, LT1. We purified this inhibitory activity and identified a polypeptide of approximately 80 kDa (p80(GCR237)) using LC-tandem MS. The amino acid sequence of p80(GCR237) had no similarity to any characterized proteins. The p80(GCR237) gene cosegregated with Tm-1; transgenic expression of p80(GCR237) conferred resistance to ToMV within tomato plants; and the knockdown of p80(GCR237) sensitized Tm-1 tomato plants to ToMV, indicating that Tm-1 encodes p80(GCR237) itself. We further show that in vitro-synthesized Tm-1 (p80(GCR237)) protein binds to the replication proteins of WT ToMV and inhibits their function at a step before, but not after, the viral replication complex is formed on the membrane surfaces. Such binding was not observed for the replication proteins of LT1. These results suggest that Tm-1 (p80(GCR237)) inhibits the replication of WT ToMV RNA through binding to the replication proteins. PMID:17699618

  15. An inhibitor of viral RNA replication is encoded by a plant resistance gene

    PubMed Central

    Ishibashi, Kazuhiro; Masuda, Kiyoshi; Naito, Satoshi; Meshi, Tetsuo; Ishikawa, Masayuki

    2007-01-01

    The tomato Tm-1 gene confers resistance to tomato mosaic virus (ToMV). Here, we report that the extracts of Tm-1 tomato cells (GCR237) have properties that inhibit the in vitro RNA replication of WT ToMV more strongly than that of the Tm-1-resistance-breaking mutant of ToMV, LT1. We purified this inhibitory activity and identified a polypeptide of ≈80 kDa (p80GCR237) using LC–tandem MS. The amino acid sequence of p80GCR237 had no similarity to any characterized proteins. The p80GCR237 gene cosegregated with Tm-1; transgenic expression of p80GCR237 conferred resistance to ToMV within tomato plants; and the knockdown of p80GCR237 sensitized Tm-1 tomato plants to ToMV, indicating that Tm-1 encodes p80GCR237 itself. We further show that in vitro-synthesized Tm-1 (p80GCR237) protein binds to the replication proteins of WT ToMV and inhibits their function at a step before, but not after, the viral replication complex is formed on the membrane surfaces. Such binding was not observed for the replication proteins of LT1. These results suggest that Tm-1 (p80GCR237) inhibits the replication of WT ToMV RNA through binding to the replication proteins. PMID:17699618

  16. Development of a Miniaturized Hollow-Waveguide Gas Correlation Radiometer for Trace Gas Measurements in the Martian Atmosphere

    NASA Technical Reports Server (NTRS)

    Wilson, Emily L.; Georgieva, E. M.; Blalock, G. W.; Marx, C. T.; Heaps, W. S.

    2012-01-01

    We present preliminary results in the development of a miniaturized gas correlation radiometer (GCR) for column trace gas measurements in the Martian atmosphere. The GCR is designed as an orbiting instrument capable of mapping multiple trace gases and identifying active regions on the Mars surface.

  17. Guiding Preservice Teachers to Critically Reflect: Towards a Renewed Sense about English Learners

    ERIC Educational Resources Information Center

    Markos, Amy Michele

    2011-01-01

    The purpose of this practitioner inquiry was to explore the use of Guided Critical Reflection (GCR) in preparing preservice teachers for English learners (ELs). As a teacher researcher, I documented, analyzed, and discussed the ways in which students in my course used the process of GCR to transform their passively held understandings about ELs.

  18. Antimicrobial-resistant fecal bacteria from ceftiofur-treated and non-antimicrobial-treated co-mingled beef cows at a cow-calf operation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We compared the occurrences of 3rd-generation cephalosporin-resistant (3GCr ), tetracycline-resistant (TETr) and trimethoprim-sulfamethoxazole-resistant (COTr ) Escherichia coli, 3GCr Salmonella enterica, nalidixic acid-resistant (NALr) S. enterica and erythromycin-resistant (ERYr) enterococci from ...

  19. Occurrence of antimicrobial-resistant Escherichia coli and Salmonella enterica in the beef cattle production and processing continuum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Specific concerns have been raised that 3rd-generation cephalosporin-resistant (3GCr) Escherichia coli, trimethoprim-sulfamethoxazole-resistant (COTr) E. coli, 3GCr Salmonella enterica, and nalidixic acid-resistant (NALr) S. enterica, may be present in cattle production environments, persist through...

  20. Guiding Preservice Teachers to Critically Reflect: Towards a Renewed Sense about English Learners

    ERIC Educational Resources Information Center

    Markos, Amy Michele

    2011-01-01

    The purpose of this practitioner inquiry was to explore the use of Guided Critical Reflection (GCR) in preparing preservice teachers for English learners (ELs). As a teacher researcher, I documented, analyzed, and discussed the ways in which students in my course used the process of GCR to transform their passively held understandings about ELs.…

  1. Astrophysical Li-7 as a product of big bang nucleosynthesis and galactic cosmic-ray spallation

    NASA Technical Reports Server (NTRS)

    Olive, Keith A.; Schramm, David N.

    1992-01-01

    The astrophysical Li-7 abundance is considered to be largely primordial, while the Be and B abundances are thought to be due to galactic cosmic ray (GCR) spallation reactions on top of a much smaller big bang component. But GCR spallation should also produce Li-7. As a consistency check on the combination of big bang nucleosynthesis and GCR spallation, the Be and B data from a sample of hot population II stars is used to subtract from the measured Li-7 abundance an estimate of the amount generated by GCR spallation for each star in the sample, and then to add to this baseline an estimate of the metallicity-dependent augmentation of Li-7 due to spallation. The singly reduced primordial Li-7 abundance is still consistent with big bang nucleosynthesis, and a single GCR spallation model can fit the Be, B, and corrected Li-7 abundances for all the stars in the sample.

  2. Three dimensional solar anisotropy of galactic cosmic rays near the recent solar minimum 23/24

    NASA Astrophysics Data System (ADS)

    Modzelewska, R.; Alania, M. V.

    2015-08-01

    Three dimensional (3D) galactic cosmic ray (GCR) anisotropy has been studied for 2006-2012. The GCR anisotropy, both in the ecliptic plane and in polar direction, were obtained based on the neutron monitors (NMs) and Nagoya muon telescopes (MT) data. We analyze two dimensional (2D) GCR anisotropy in the ecliptic plane and north-south anisotropy normal to the ecliptic plane. We reveal quasi-periodicities - the annual and 27-days waves in the GCR anisotropy in 2006-2012. We investigate the relationship of the 27-day variation of the GCR anisotropy in the ecliptic plane and in the polar direction with the parameters of solar activity and solar wind.

  3. Galactic cosmic ray simulation at the NASA Space Radiation Laboratory.

    PubMed

    Norbury, John W; Schimmerling, Walter; Slaba, Tony C; Azzam, Edouard I; Badavi, Francis F; Baiocco, Giorgio; Benton, Eric; Bindi, Veronica; Blakely, Eleanor A; Blattnig, Steve R; Boothman, David A; Borak, Thomas B; Britten, Richard A; Curtis, Stan; Dingfelder, Michael; Durante, Marco; Dynan, William S; Eisch, Amelia J; Robin Elgart, S; Goodhead, Dudley T; Guida, Peter M; Heilbronn, Lawrence H; Hellweg, Christine E; Huff, Janice L; Kronenberg, Amy; La Tessa, Chiara; Lowenstein, Derek I; Miller, Jack; Morita, Takashi; Narici, Livio; Nelson, Gregory A; Norman, Ryan B; Ottolenghi, Andrea; Patel, Zarana S; Reitz, Guenther; Rusek, Adam; Schreurs, Ann-Sofie; Scott-Carnell, Lisa A; Semones, Edward; Shay, Jerry W; Shurshakov, Vyacheslav A; Sihver, Lembit; Simonsen, Lisa C; Story, Michael D; Turker, Mitchell S; Uchihori, Yukio; Williams, Jacqueline; Zeitlin, Cary J

    2016-02-01

    Most accelerator-based space radiation experiments have been performed with single ion beams at fixed energies. However, the space radiation environment consists of a wide variety of ion species with a continuous range of energies. Due to recent developments in beam switching technology implemented at the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL), it is now possible to rapidly switch ion species and energies, allowing for the possibility to more realistically simulate the actual radiation environment found in space. The present paper discusses a variety of issues related to implementation of galactic cosmic ray (GCR) simulation at NSRL, especially for experiments in radiobiology. Advantages and disadvantages of different approaches to developing a GCR simulator are presented. In addition, issues common to both GCR simulation and single beam experiments are compared to issues unique to GCR simulation studies. A set of conclusions is presented as well as a discussion of the technical implementation of GCR simulation. PMID:26948012

  4. Cosmic rays and climate change over the past 1000 million years

    NASA Astrophysics Data System (ADS)

    Sloan, T.; Wolfendale, A. W.

    2013-12-01

    The Galactic cosmic ray (GCR) intensity has been postulated by others to vary cyclically with a peak to valley ratio of ˜3:1, as the Solar System moves from the Spiral Arm to the Inter-Arm regions of the Galaxy. These intensities have been correlated with global temperatures and used to support the hypothesis of GCR induced climate change. In this paper we show that the model used to deduce such a large ratio of Arm to Interarm GCR intensity requires unlikely values of some of the GCR parameters, particularly the diffusion length in the interstellar medium, if as seems likely to be the case, the diffusion is homogeneous. Comparison is made with the existing gamma ray astronomy data and this also indicates that the ratio is not large. The variation in the intensity is probably of order 10-20% and should be no more than 30% as the Solar System moves between these two regions, unless the conventional parameters of the GCR are incorrect. In addition we show that the variation of the GCR intensity, as the trajectory of the Solar System oscillates about the Galactic Plane, is too small to account for the extinctions of species as has been postulated unless, again, conventional assumptions about the GCR parameters are not correct.

  5. MODULATION OF GALACTIC COSMIC RAYS OBSERVED AT L1 IN SOLAR CYCLE 23

    SciTech Connect

    Fludra, A.

    2015-01-20

    We analyze a unique 15 yr record of galactic cosmic-ray (GCR) measurements made by the SOHO Coronal Diagnostic Spectrometer NIS detectors, recording integrated GCR numbers with energies above 1.0 GeV between 1996 July and 2011 June. We are able to closely reproduce the main features of the SOHO/CDS GCR record using the modulation potential calculated from neutron monitor data by Usoskin et al. The GCR numbers show a clear solar cycle modulation: they decrease by 50% from the 1997 minimum to the 2000 maximum of the solar cycle, then return to the 1997 level in 2007 and continue to rise, in 2009 December reaching a level 25% higher than in 1997. This 25% increase is in contrast with the behavior of Ulysses/KET GCR protons extrapolated to 1 AU in the ecliptic plane, showing the same level in 2008-2009 as in 1997. The GCR numbers are inversely correlated with the tilt angle of the heliospheric current sheet. In particular, the continued increase of SOHO/CDS GCRs from 2007 until 2009 is correlated with the decrease of the minimum tilt angle from 30° in mid-2008 to 5° in late 2009. The GCR level then drops sharply from 2010 January, again consistent with a rapid increase of the tilt angle to over 35°. This shows that the extended 2008 solar minimum was different from the 1997 minimum in terms of the structure of the heliospheric current sheet.

  6. Modulation of Galactic Cosmic Rays Observed at L1 in Solar Cycle 23

    NASA Astrophysics Data System (ADS)

    Fludra, A.

    2015-01-01

    We analyze a unique 15 yr record of galactic cosmic-ray (GCR) measurements made by the SOHO Coronal Diagnostic Spectrometer NIS detectors, recording integrated GCR numbers with energies above 1.0 GeV between 1996 July and 2011 June. We are able to closely reproduce the main features of the SOHO/CDS GCR record using the modulation potential calculated from neutron monitor data by Usoskin et al. The GCR numbers show a clear solar cycle modulation: they decrease by 50% from the 1997 minimum to the 2000 maximum of the solar cycle, then return to the 1997 level in 2007 and continue to rise, in 2009 December reaching a level 25% higher than in 1997. This 25% increase is in contrast with the behavior of Ulysses/KET GCR protons extrapolated to 1 AU in the ecliptic plane, showing the same level in 2008-2009 as in 1997. The GCR numbers are inversely correlated with the tilt angle of the heliospheric current sheet. In particular, the continued increase of SOHO/CDS GCRs from 2007 until 2009 is correlated with the decrease of the minimum tilt angle from 30° in mid-2008 to 5° in late 2009. The GCR level then drops sharply from 2010 January, again consistent with a rapid increase of the tilt angle to over 35°. This shows that the extended 2008 solar minimum was different from the 1997 minimum in terms of the structure of the heliospheric current sheet.

  7. Glucocorticoid (GC) sensitivity and GC receptor expression differ in thymocyte subpopulations.

    PubMed

    Berki, Timea; Pálinkás, László; Boldizsár, Ferenc; Németh, Péter

    2002-05-01

    Positive and negative selection steps in the thymus prevent non-functional or harmful T cells from reaching the periphery. To examine the role of glucocorticoid (GC) hormone and its intracellular receptor (GCR) in thymocyte development we measured the GCR expression in different thymocyte subpopulations of BALB/c mice with or without previous dexamethasone (DX), anti-CD3 mAb, RU-486 and RU-43044 treatment. Four-color labeling of thymocytes allowed detection of surface CD4/CD8/CD69 expression in parallel with intracellular GCR molecules by flow cytometry. Double-positive (DP) CD4+CD8+ thymocytes showed the lowest GCR expression compared to double-negative (DN) CD4-CD8- thymocytes and mature single-positive (SP) cells. DX treatment caused a concentration-dependent depletion of the DP cell population and increased appearance of mature SP cells with reduced GCR levels. GCR antagonists (RU-486 or RU-43044) did not influence the effect of DX on thymocyte composition; however, RU-43044 inhibited the high-dose GC-induced GCR down-regulation in SP and DN cells. GCR antagonists alone did not influence the maturation of thymocytes and receptor numbers. Combined low-dose anti-CD3 mAb and DX treatment caused an enhanced maturation (positive selection) of thymocytes followed by the elevation of CD69+ DP cells. The sensitivity of DP thymocytes with a GCRlow phenotype to GC action and the ineffectiveness of the GCR antagonist treatment may reflect a non-genomic GC action in the thymic selection steps. PMID:11978776

  8. Solar activity, the QBO, and tropospheric responses

    NASA Technical Reports Server (NTRS)

    Tinsley, Brian A.; Brown, Geoffrey M.; Scherrer, Philip H.

    1989-01-01

    The suggestion that galactic cosmic rays (GCR) as modulated by the solar wind are the carriers of the component of solar variability that affects weather and climate has been discussed in the literature for 30 years, and there is now a considerable body of evidence that supports it. Variations of GCR occur with the 11 year solar cycle, matching the time scale of recent results for atmospheric variations, as modulated by the quasibiennial oscillation of equatorial stratospheric winds (the QBO). Variations in GCR occur on the time scale of centuries with a well defined peak in the coldest decade of the little ice age. New evidence is presented on the meteorological responses to GCR variations on the time scale of a few days. These responses include changes in the vertical temperature profile in the troposphere and lower stratosphere in the two days following solar flare related high speed plasma streams and associated GCR decreases, and in decreases in Vorticity Area Index (VAI) following Forbush decreases of GCR. The occurrence of correlations of GCR and meteorological responses on all three time scales strengthens the hypothesis of GCR as carriers of solar variability to the lower atmosphere. Both short and long term tropospheric responses are understandable as changes in the intensity of cyclonic storms initiated by mechanisms involving cloud microphysical and cloud electrification processes, due to changes in local ion production from changes in GCR fluxes and other high energy particles in the MeV to low GeV range. The nature of these mechanisms remains undetermined. Possible stratospheric wind (particularly QBO) effects on the transport of HNO3 and other constituents incorporated in cluster ions and possible condensation and freezing nuclei are considered as relevant to the long term variations.

  9. Practical Applications of Cosmic Ray Science: Spacecraft, Aircraft, Ground-Based Computation and Control Systems, Exploration, and Human Health and Safety

    NASA Technical Reports Server (NTRS)

    Koontz, Steve

    2015-01-01

    In this presentation a review of galactic cosmic ray (GCR) effects on microelectronic systems and human health and safety is given. The methods used to evaluate and mitigate unwanted cosmic ray effects in ground-based, atmospheric flight, and space flight environments are also reviewed. However not all GCR effects are undesirable. We will also briefly review how observation and analysis of GCR interactions with planetary atmospheres and surfaces and reveal important compositional and geophysical data on earth and elsewhere. About 1000 GCR particles enter every square meter of Earth’s upper atmosphere every second, roughly the same number striking every square meter of the International Space Station (ISS) and every other low- Earth orbit spacecraft. GCR particles are high energy ionized atomic nuclei (90% protons, 9% alpha particles, 1% heavier nuclei) traveling very close to the speed of light. The GCR particle flux is even higher in interplanetary space because the geomagnetic field provides some limited magnetic shielding. Collisions of GCR particles with atomic nuclei in planetary atmospheres and/or regolith as well as spacecraft materials produce nuclear reactions and energetic/highly penetrating secondary particle showers. Three twentieth century technology developments have driven an ongoing evolution of basic cosmic ray science into a set of practical engineering tools needed to design, test, and verify the safety and reliability of modern complex technological systems and assess effects on human health and safety effects. The key technology developments are: 1) high altitude commercial and military aircraft; 2) manned and unmanned spacecraft; and 3) increasingly complex and sensitive solid state micro-electronics systems. Space and geophysical exploration needs drove the development of the instruments and analytical tools needed to recover compositional and structural data from GCR induced nuclear reactions and secondary particle showers. Finally, the possible role of GCR secondary particle showers in addressing an important homeland security problem, finding nuclear contraband and weapons, will be briefly reviewed.

  10. Multiplex Assay for Protein Profiling and Potency Measurement of German Cockroach Allergen Extracts

    PubMed Central

    Khurana, Taruna; Dobrovolskaia, Ekaterina; Shartouny, Jessica R.; Slater, Jay E.

    2015-01-01

    Background German cockroach (GCr) allergens induce IgE responses and may cause asthma. Commercial GCr allergen extracts are variable and existing assays may not be appropriate for determining extract composition and potency. Objective Our aim was to develop a multiplex antibody/bead-based assay for assessment of GCr allergen extracts. Methods Single chain fragment variable (scFv) antibodies against GCr were obtained by screening libraries derived from naïve human lymphocytes and hyperimmunized chicken splenocytes and bone marrow. Selected clones were sequenced and characterized by immunoblotting. Eighteen scFv antibodies (17 chicken, 1 human) coupled to polystyrene beads were used in this suspension assay; binding of targeted GCr allergens to antibody-coated beads was detected using rabbit antisera against GCr, and against specific allergens rBla g 1, rBla g 2, and rBla g 4. The assay was tested for specificity, accuracy, and precision. Extracts were also compared by IgE competition ELISA. Results Chicken scFv’s generated eight different binding patterns to GCr proteins from 14 to 150 kDa molecular weight. Human scFv’s recognized a 100 kDa GCr protein. The multiplex assay was found to be specific and reproducible with intra-assay coefficient of variation (CV) of 2.64% and inter-assay CV of 10.0%. Overall potencies of various GCr extracts were calculated using mean logEC50s for eight selected scFvs. Overall potency measures were also analyzed by assessing the contributions to potency of each target. Conclusions An scFv antibody-based multiplex assay has been developed capable of simultaneously measuring different proteins in a complex mixture, and to determine the potencies and compositions of allergen extracts. PMID:26444288

  11. Sun Cycles as Interchange of Low-dimension Attractors in Chaotic Dynamics of Solar Activity

    NASA Astrophysics Data System (ADS)

    Kozlov, Valery

    The scale-invariant character (a scaling) of the cosmic ray scintillation dynamics observed during GCR intensity decreases of different scales is proved by the monofractal dependence of the correlation dimension of a process with the explicitly express plateau: d=2.5±0.1. The scaling of GCR scintillation dynamics reflects the hierarchically self-similarity, i. e. a fractal structure of GCR intensity decreases at the geoeffective phase of the 11-year solar cycle. The "window of order" in the chaotic, on the whole, dynamics of solar activity correspond to the low-dimension attractor, and the interchange of "windows of order" is manifested as solar cycles.

  12. Pulsed Magnetic Field Driven Gas Core Reactors for Space Power & Propulsion Applications

    NASA Technical Reports Server (NTRS)

    Anghaie, Samim; Smith, Blair; Knight, Travis; Butler, Carey

    2003-01-01

    The present results indicated that: 1. A pulsed magnetic driven fission power concept, PMD-GCR is developed for closed (NER) and semi-open (NTR) operations. 2. In power mode, power is generated at alpha less than 1 for power levels of hundreds of KW or higher 3. IN semi open NTR mode, PMD-GCR generates thrust at I(sub sp) approx. 5,000 s and jet power approx. 5KW/Kg. 4. PMD-GCR is highly subcritical and is actively driven to critically. 5. Parallel path with fusion R&D needs in many areas including magnet and plasma.

  13. Galactic Cosmic Ray Simulation at the NASA Space Radiation Laboratory

    NASA Technical Reports Server (NTRS)

    Norbury, John W.; Slaba, Tony C.; Rusek, Adam

    2015-01-01

    The external Galactic Cosmic Ray (GCR) spectrum is significantly modified when it passes through spacecraft shielding and astronauts. One approach for simulating the GCR space radiation environment at ground based accelerators would use the modified spectrum, rather than the external spectrum, in the accelerator beams impinging on biological targets. Two recent workshops have studied such GCR simulation. The first workshop was held at NASA Langley Research Center in October 2014. The second workshop was held at the NASA Space Radiation Investigators' workshop in Galveston, Texas in January 2015. The results of these workshops will be discussed in this paper.

  14. Iron Isotopes in the Metal Phase of IAB Iron Meteorites

    NASA Astrophysics Data System (ADS)

    Cook, D. L.; Burkhard, R.; Schönbächler, M.; Leya, I.

    2015-07-01

    We analyzed IAB irons with a range of CRE ages to investigate whether effects from GCR may influence Fe isotopes. No resolvable anomalies were observed. Modeling of potential cosmic ray effects on Fe are underway to compare to our observations.

  15. Particle Radiation Environments and Their Effects at Planetary Surfaces of Airless Bodies: Remote Sensing Lessons Learned at the Moon by LRO/CRaTER and Extension to Other Planetary Objects

    NASA Astrophysics Data System (ADS)

    Spence, H. E.; Schwadron, N. A.; Wilson, J. K.; Jordan, A. P.; Winslow, R.; Joyce, C.; Looper, M. D.; Case, A. W.; Stubbs, T. J.; Zeitlin, C.; Blake, J. B.; Kasper, J. C.; Mazur, J. E.; Smith, S. S.; Townsend, L. W.

    2015-11-01

    We summarize the physics of GCR and SEP interactions with the Moon's surface and quantify how these same processes operate at similar airless objects throughout the solar system, including at Mercury, Mars' moons, asteroids, and the Pluto system.

  16. Validation of Cosmic Ray Ionization Model CORIMIA applied for solar energetic particles and Anomalous Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Asenovski, S.; Velinov, P.; Mateev, L.

    2016-02-01

    Based on the electromagnetic interaction between the cosmic ray (CR) and the atmospheric neutral constituents, CORIMIA (COsmic Ray Ionization Model) gives an estimation of the dynamical ionization condition of the lower ionosphere and middle atmosphere (about 30-120 km). Galactic Cosmic Rays (GCR), modified by solar wind and later by geomagnetic and atmospheric cut offs, produce ionization in the entire atmosphere. In this paper we show the GCR ionization in periods of solar minimum and maximum. Despite the considerably lower energies than GCR, Anomalous Cosmic Rays (ACR) contribute to the ionization state mostly over the polar regions and as we present here this contribution is comparable with those of GCR. Solar energetic particles (SEP), which differ vastly from one another for different solar events, can be responsible for significant ionization over the high latitude regions. Here we compare flows of SEP caused by two of the most powerful solar proton events at February 23, 1956 and January 20, 2005.

  17. Comparison of Space Radiation Calculations from Deterministic and Monte Carlo Transport Codes

    NASA Technical Reports Server (NTRS)

    Adams, J. H.; Lin, Z. W.; Nasser, A. F.; Randeniya, S.; Tripathi, r. K.; Watts, J. W.; Yepes, P.

    2010-01-01

    The presentation outline includes motivation, radiation transport codes being considered, space radiation cases being considered, results for slab geometry, results from spherical geometry, and summary. ///////// main physics in radiation transport codes hzetrn uprop fluka geant4, slab geometry, spe, gcr,

  18. Observations of the Li, Be, and B Isotopes and Constraints on Cosmic-ray Propagation

    NASA Technical Reports Server (NTRS)

    deNolfo, G. A.; Moskalenko, I. V.; Binns, W. R.; Christian, E. R.; Cummings, A. C.; Davis, A. J.; George, J. S.; Hink, P. L.; Israel, M. H.; Leske, R. A.; Lijowski, M.; Mewaldt, R. A.; Stone, E. C.; Strong, A. W.; vonRosenvinge, T. T.; Wiedenbeck, M. E.; Yanasak, N. E.

    2007-01-01

    The abundance of Li, Be, and B isotopes in galactic cosmic rays (GCR) between E=50-200 MeV/nucleon has been observed by the Cosmic Ray Isotope Spectrometer (CRIS) on NASA's ACE mission since 1997 with high statistical accuracy. Precise observations of Li, Be, B can be used to constrain GCR propagation models. We find that a diffusive reacceleration model with parameters that best match CRIS results (e.g. B/C, Li/C, etc) are also consistent with other GCR observations. A approx. 15-20% overproduction of Li and Be in the model predictions is attributed to uncertainties in the production cross-section data. The latter becomes a significant limitation to the study of rare GCR species that are generated predominantly via spallation.

  19. Geant4-based radiation hazard assessment for human exploration missions

    NASA Astrophysics Data System (ADS)

    Bernabeu, J.; Casanova, I.

    Human exploration missions in the Solar System will spend most of the time in deep space, without the shielding from the Earth's magnetic field and hence, directly exposed to Galactic Cosmic Rays (GCR) and Solar Particle Events (SPE). Both GCR and SPE fluences have been used to calculate the dose deposited on a water slab phantom using MULASSIS, a program based on the Geant4 Monte Carlo particle transport code. Doses from several extreme SPE events and from a GCR model are calculated for different shielding materials and thicknesses using a planar slab geometry and compared to current dose limits for space operations. Cross-comparison of MULASSIS with HZETRN (a deterministic code) has also been performed for SPE and GCR environments showing an overall reasonable agreement between both codes.

  20. Observations of the Li, Be, and B isotopes and Constraints on Cosmic-ray Propagation

    SciTech Connect

    de Nolfo, Georgia A.; Moskalenko, I.V.; Binns, W.R.; Christian, E.R.; Cummings, A.C.; Davis, A.J.; George, J.S.; Hink, P.L.; Israel, M.H.; Leske, R.A.; Lijowski, M.; Mewaldt, R.A.; Stone, E.C.; Strong, A.W.; von Rosenvinge, T.T.; Wiedenbeck, M.E.; Yanasak, N.E.; /NASA, Goddard /Stanford U., HEPL /Washington U., St. Louis /NASA, Headquarters /Caltech, SRL /Aerospace Corp. /Garching, Max Planck Inst., MPE /Caltech, JPL

    2006-11-15

    The abundance of Li, Be, and B isotopes in galactic cosmic rays (GCR) between E=50-200 MeV/nucleon has been observed by the Cosmic Ray Isotope Spectrometer (CRIS) on NASA's ACE mission since 1997 with high statistical accuracy. Precise observations of Li, Be, B can be used to constrain GCR propagation models. We find that a diffusive reacceleration model with parameters that best match CRIS results (e.g. B/C, Li/C, etc) are also consistent with other GCR observations. A {approx}15-20% overproduction of Li and Be in the model predictions is attributed to uncertainties in the production cross-section data. The latter becomes a significant limitation to the study of rare GCR species that are generated predominantly via spallation.

  1. Energy, water, and carbon fluxes in a loblolly pine stand: Results from uniform and gappy canopy models with comparisons to eddy flux data

    NASA Astrophysics Data System (ADS)

    Song, Conghe; Katul, Gabriel; Oren, Ram; Band, Lawrence E.; Tague, Christina L.; Stoy, Paul C.; McCarthy, Heather R.

    2009-12-01

    This study investigates the impacts of canopy structure specification on modeling net radiation (Rn), latent heat flux (LE) and net photosynthesis (An) by coupling two contrasting radiation transfer models with a two-leaf photosynthesis model for a maturing loblolly pine stand near Durham, North Carolina, USA. The first radiation transfer model is based on a uniform canopy representation (UCR) that assumes leaves are randomly distributed within the canopy, and the second radiation transfer model is based on a gappy canopy representation (GCR) in which leaves are clumped into individual crowns, thereby forming gaps between the crowns. To isolate the effects of canopy structure on model results, we used identical model parameters taken from the literature for both models. Canopy structure has great impact on energy distribution between the canopy and the forest floor. Comparing the model results, UCR produced lower Rn, higher LE and higher An than GCR. UCR intercepted more shortwave radiation inside the canopy, thus producing less radiation absorption on the forest floor and in turn lower Rn. There is a higher degree of nonlinearity between An estimated by UCR and by GCR than for LE. Most of the difference for LE and An between UCR and GCR occurred around noon, when gaps between crowns can be seen from the direction of the incident sunbeam. Comparing with eddy-covariance measurements in the same loblolly pine stand from May to September 2001, based on several measures GCR provided more accurate estimates for Rn, LE and An than UCR. The improvements when using GCR were much clearer when comparing the daytime trend of LE and An for the growing season. Sensitivity analysis showed that UCR produces higher LE and An estimates than GCR for canopy cover ranging from 0.2 to 0.8. There is a high degree of nonlinearity in the relationship between UCR estimates for An and those of GCR, particularly when canopy cover is low, and suggests that simple scaling of UCR parameters cannot compensate for differences between the two models. LE from UCR and GCR is also nonlinearly related when canopy cover is low, but the nonlinearity quickly disappears as canopy cover increases, such that LE from UCR and GCR are linearly related and the relationship becomes stronger as canopy cover increases. These results suggest the uniform canopy assumption can lead to underestimation of Rn, and overestimation of LE and An. Given the potential in mapping regional scale forest canopy structure with high spatial resolution optical and Lidar remote sensing plotforms, it is possible to use GCR for up-scaling ecosystem processes from flux tower measurements to heterogeneous landscapes, provided the heterogeneity is not too extreme to modify the flow dynamics.

  2. Galactic cosmic ray radiation levels in spacecraft on interplanetary missions

    NASA Technical Reports Server (NTRS)

    Shinn, J. L.; Nealy, J. E.; Townsend, L. W.; Wilson, J. W.; Wood, J.S.

    1994-01-01

    Using the Langley Research Center Galactic Cosmic Ray (GCR) transport computer code (HZETRN) and the Computerized Anatomical Man (CAM) model, crew radiation levels inside manned spacecraft on interplanetary missions are estimated. These radiation-level estimates include particle fluxes, LET (Linear Energy Transfer) spectra, absorbed dose, and dose equivalent within various organs of interest in GCR protection studies. Changes in these radiation levels resulting from the use of various different types of shield materials are presented.

  3. History of the solar environment

    NASA Astrophysics Data System (ADS)

    Marti, Kurt; Lavielle, Bernard

    2009-03-01

    Galactic cosmic rays (GCR) provide information on the solar neighborhood during the sun's motion in the galaxy. There is now considerable evidence for GCR acceleration by shock waves of supernova in active star-forming regions (OB associations) in the galactic spiral arms. During times of passage into star-forming regions increases in the GCR-flux are expected. Recent data from the Spitzer Space Telescope (SST) are shedding light on the structure of the Milky Way and of its star-forming-regions in spiral arms. Records of flux variations may be found in solar system detectors, and iron meteorites with GCR-exposure times of several hundred million years have long been considered to be potential detectors (Voshage, 1962). Variable concentration ratios of GCR-produced stable and radioactive nuclides, with varying half-lives and therefore integration times, were reported by Lavielle et al. (1999), indicating a recent 38% GCR-flux increase. Potential flux recorders consisting of different pairs of nuclides can measure average fluxes over different time scales (Lavielle et al., 2007; Mathew and Marti, 2008). Specific characteristics of two pairs of recorders (81Kr-Kr and 129I-129Xe) are the properties of self-correction for GCR-shielding (flux variability within meteorites of varying sizes). The 81Kr-Kr method (Marti, 1967) is based on Kr isotope ratios, while stable 129Xe is the decay product of the radionuclide 129I, which is produced by secondary neutron reactions on Te in troilites of iron meteorites. The two chronometers provide records of the average GCR flux over 1 and 100 million year time scales, respectively.

  4. Activation of glucocorticoid receptors in Müller glia is protective to retinal neurons and suppresses microglial reactivity.

    PubMed

    Gallina, Donika; Zelinka, Christopher Paul; Cebulla, Colleen M; Fischer, Andy J

    2015-11-01

    Reactive microglia and macrophages are prevalent in damaged retinas. Glucocorticoid signaling is known to suppress inflammation and the reactivity of microglia and macrophages. In the vertebrate retina, the glucocorticoid receptor (GCR) is known to be activated and localized to the nuclei of Müller glia (Gallina et al., 2014). Accordingly, we investigated how signaling through GCR influences the survival of neurons using the chick retina in vivo as a model system. We applied intraocular injections of GCR agonist or antagonist, assessed microglial reactivity, and the survival of retinal neurons following different damage paradigms. Microglial reactivity was increased in retinas from eyes that were injected with vehicle, and this reactivity was decreased by GCR-agonist dexamethasone (Dex) and increased by GCR-antagonist RU486. We found that activation of GCR suppresses the reactivity of microglia and inhibited the loss of retinal neurons resulting from excitotoxicity. We provide evidence that the protection-promoting effects of Dex were maintained when the microglia were selectively ablated. Similarly, intraocular injections of Dex protected ganglion cells from colchicine-treatment and protected photoreceptors from damage caused by retinal detachment. We conclude that activation of GCR promotes the survival of ganglion cells in colchicine-damaged retinas, promotes the survival of amacrine and bipolar cells in excitotoxin-damaged retinas, and promotes the survival of photoreceptors in detached retinas. We propose that suppression of microglial reactivity is secondary to activation of GCR in Müller glia, and this mode of signaling is an effective means to lessen the damage and vision loss resulting from different types of retinal damage. PMID:26272753

  5. Grey Component Replacement Research, Modelling Tone And Color Reproduction

    NASA Astrophysics Data System (ADS)

    Fisch, Richard S.

    1990-06-01

    Four different scanning Color Electronic Pagination System (CEPS) devices were tested to study their conventional and Grey Component Replacement/Undercolor Addition (GCR/UCA) tone and color response in the 4 color Positive Acting Offset Lithographic printing process. A common transparency input and ganged printing output was used. Inter and intra machine differences are disclosed. A new depiction of the full tone reproduction characteristics is presented for several different levels of GCR/UCA and conventional printing.

  6. Experimental study and theoretical modeling of the long period variations of Galactic Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Alania, Michael; Siluszyk, Marek; Wawrzynczak-Szaban, Anna

    2012-07-01

    We analyze experimental data of neutron monitors and solar wind parameters during #21 solar cycle (1976-1987). In galactic cosmic ray (GCR) intensity is well established a step like changes in both ascending and descending periods of solar activity. We compose two-dimensional (2-D) time dependent model of GCR modulation based on Parker's transport equation to explain a general 11-year wave of the GCR intensity with the step-like changes, and each step-like changes individually, i.e. time scale of investigations is carried out by means of daily and monthly data. An innovation in proposed model is that besides the well known fundamental processes responsible for modulation of the GCR intensity, we implement in the model the parameters characterizing temporal changes of the exponent n of the Power Spectral Density (PSD) of the Interplanetary Magnetic Field (IMF) turbulence, module B of the IMF, tilt angle δ of the Heliospheric Neutral Sheet, and changes of drift effect of the GCR particles upon solar activity assuming that drift effect of the GCR particles is maximal in the minimum epoch, when drift dominates, and is neglected in the maximum epoch, when diffusion dominates. We show that an acceptable compatibility is kept for the investigated period of 1976-1987 (solar cycle #21), when the expected temporal changes of the GCR particles density (11-year wave) is shifted for 18 months with respect to the temporal changes of the smoothed experimental data of the GCR intensity. We consider, that a delay time ˜18 months can be considered as an effective delay time caused by the combined influence of all parameters implemented in the 2-D model.

  7. Radiation environment during the long space mission (Mars) due to galactic cosmic rays

    SciTech Connect

    Pissarenko, N.F.

    1993-12-31

    Galactic cosmic radiation (GCR) mostly determines dose equivalents inside the spacecraft during long-term manned missions in space. In this paper some new results are collected concerning different characteristics of GCR`s. Together with earlier obtained data they show that during most part of the solar cycle such spacecflights are not possible. Attention is drawn to very great errors in the estimates of dose equivalent and shielding thickness.

  8. Galactic Cosmic Ray Access to the Inner Magnetosphere Measured by the Relativistic Proton Spectrometer aboard the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Looper, M. D.; Mazur, J. E.; O'Brien, T. P.; George, J. S.

    2013-12-01

    The Relativistic Proton Spectrometer (RPS) aboard the Van Allen Probes is designed to measure the energy and angular distributions of protons with energies of about 50 MeV to 2 GeV that are trapped in the Earth's inner radiation belt. The upper end of this energy range also covers the peak of the galactic cosmic ray (GCR) spectrum, and when each spacecraft is near apogee we obtain a clean sample of GCR protons at locations well outside the region populated by trapped protons at these energies. As each spacecraft moves closer to Earth, the increasing strength of the geomagnetic field shunts away protons of progressively higher energies, a process that can be studied by analyzing the changes in the measured GCR spectrum as the sensor is carried toward and back away from apogee. In addition, the spin of the Van Allen Probes spacecraft allows us to study the east-west asymmetry of GCR protons, as the arcs of gyration of the protons that are measured at the spacecraft bring them to the sensors along different tracks through the outer parts of the Earth's magnetic field. We will present observations of these effects from the lowest altitudes reached by GCR protons out to apogee at about L = 6 over the mission to date, using data from the CRaTER sensor aboard the Lunar Reconnaissance Orbiter as a baseline for variations of the GCR flux well outside the magnetosphere.

  9. NASA Galactic Cosmic Radiation Environment Model: Badhwar - O'Neill (2014)

    NASA Technical Reports Server (NTRS)

    Golge, S.; O'Neill, P. M.; Slaba, T. C.

    2015-01-01

    The Badhwar-O'Neill (BON) Galactic Cosmic Ray (GCR) flux model has been used by NASA to certify microelectronic systems and in the analysis of radiation health risks for human space flight missions. Of special interest to NASA is the kinetic energy region below 4.0 GeV/n due to the fact that exposure from GCR behind shielding (e.g., inside a space vehicle) is heavily influenced by the GCR particles from this energy domain. The BON model numerically solves the Fokker-Planck differential equation to account for particle transport in the heliosphere due to diffusion, convection, and adiabatic deceleration under the assumption of a spherically symmetric heliosphere. The model utilizes a comprehensive database of GCR measurements from various particle detectors to determine boundary conditions. By using an updated GCR database and improved model fit parameters, the new BON model (BON14) is significantly improved over the previous BON models for describing the GCR radiation environment of interest to human space flight.

  10. NASA Galactic Cosmic Radiation Environment Model: Badhwar-O'Neill (2014)

    NASA Technical Reports Server (NTRS)

    O'Neill, P. M.; Golge, S.; Slaba, T. C.

    2015-01-01

    The Badhwar-O'Neill (BON) Galactic Cosmic Ray (GCR) flux model is used by NASA to certify microelectronic systems and in the analysis of radiation health risks for human space flight missions. Of special interest to NASA is the kinetic energy region below 4.0 GeV/n due to the fact that exposure from GCR behind shielding (e.g., inside a space vehicle) is heavily influenced by the GCR particles from this energy domain. The BON model numerically solves the Fokker-Planck differential equation to account for particle transport in the heliosphere due to diffusion, convection, and adiabatic deceleration under the assumption of a spherically symmetric heliosphere. The model utilizes a GCR measurements database from various particle detectors to determine the boundary conditions. By using an updated GCR database and improved model fit parameters, the new BON model (BON14) is significantly improved over the previous BON models for describing the GCR radiation environment of interest to human space flight.

  11. Monitoring Short-term Cosmic-ray Spectral Variations Using Neutron Monitor Time-delay Measurements

    NASA Astrophysics Data System (ADS)

    Ruffolo, D.; Sáiz, A.; Mangeard, P.-S.; Kamyan, N.; Muangha, P.; Nutaro, T.; Sumran, S.; Chaiwattana, C.; Gasiprong, N.; Channok, C.; Wuttiya, C.; Rujiwarodom, M.; Tooprakai, P.; Asavapibhop, B.; Bieber, J. W.; Clem, J.; Evenson, P.; Munakata, K.

    2016-01-01

    Neutron monitors (NMs) are ground-based detectors of cosmic-ray showers that are widely used for high-precision monitoring of changes in the Galactic cosmic-ray (GCR) flux due to solar storms and solar wind variations. In the present work, we show that a single neutron monitor station can also monitor short-term changes in the GCR spectrum, avoiding the systematic uncertainties in comparing data from different stations, by means of NM time-delay histograms. Using data for 2007-2014 from the Princess Sirindhorn Neutron Monitor, a station at Doi Inthanon, Thailand, with the world’s highest vertical geomagnetic cutoff rigidity of 16.8 GV, we have developed an analysis of time-delay histograms that removes the chance coincidences that can dominate conventional measures of multiplicity. We infer the “leader fraction” L of neutron counts that do not follow a previous neutron count in the same counter from the same atmospheric secondary, which is inversely related to the actual multiplicity and increases for increasing GCR spectral index. After correction for atmospheric pressure and water vapor, we find that L indicates substantial short-term GCR spectral hardening during some but not all Forbush decreases in GCR flux due to solar storms. Such spectral data from Doi Inthanon provide information about cosmic-ray energies beyond the Earth’s maximum geomagnetic cutoff, extending the reach of the worldwide NM network and opening a new avenue in the study of short-term GCR decreases.

  12. Near-Earth Cosmic Ray Decreases Associated with Remote Coronal Mass Ejections

    NASA Astrophysics Data System (ADS)

    Thomas, S. R.; Owens, M. J.; Lockwood, M.; Barnard, L.; Scott, C. J.

    2015-03-01

    Galactic cosmic ray (GCR) flux is modulated by both particle drift patterns and solar wind structures on a range of timescales. Over solar cycles, GCR flux varies as a function of the total open solar magnetic flux and the latitudinal extent of the heliospheric current sheet. Over hours, drops of a few percent in near-Earth GCR flux (Forbush decreases, FDs) are well known to be associated with the near-Earth passage of solar wind structures resulting from corotating interaction regions (CIRs) and transient coronal mass ejections (CMEs). We report on four FDs seen at ground-based neutron monitors which cannot be immediately associated with significant structures in the local solar wind. Similarly, there are significant near-Earth structures which do not produce any corresponding GCR variation. Three of the FDs are during the STEREO era, enabling in situ and remote observations from three well-separated heliospheric locations. Extremely large CMEs passed the STEREO-A spacecraft, which was behind the West limb of the Sun, approximately 2-3 days before each near-Earth FD. Solar wind simulations suggest that the CMEs combined with pre-existing CIRs, enhancing the pre-existing barriers to GCR propagation. Thus these observations provide strong evidence for the modulation of GCR flux by remote solar wind structures.

  13. Analysis distribution of galactic cosmic rays particle energy with polar orbit satellite for Geant4 application

    NASA Astrophysics Data System (ADS)

    Suparta, W.; Putro, W. S.

    2014-04-01

    Galactic Cosmic Rays (GCR) are photon waves originating from astrophysical sources which traverse through the interstellar/interplanetary medium and reaching the terrestrial atmosphere. The energies of Galactic Cosmic Ray particles up to and exceeding 1012 eV, and this spectrum are peaked around 1 GeV. The National Aeronautics and Space Administration (NASA) provide satellite mission for monitoring the energy GCR particles in polar orbit, so-called the ACE and OMNI. In this paper, we analyze results from measurement error of GCR sensor. The error result is obtained by comparing the measurements from GCR sensor with ground-based neutron monitors at Bartol University. The measurements were taken for two periods during a Solar Particle Event (SPE) maximum on 14 July 2000 and 28 October 2003. The largest value of measurement error from GCR sensor in this study is OMNI satellites. After the error results were obtained, they were applied into Geant4 simulation. This simulation shows the shape of particle energy distribution of GCR sensors. The simulation has been tested and can be operated very well under Linux based platform.

  14. The boron-to-beryllium ratio in halo stars - A signature of cosmic-ray nucleosynthesis in the early Galaxy

    NASA Technical Reports Server (NTRS)

    Walker, T. P.; Steigman, G.; Schramm, D. N.; Olive, K. A.; Fields, B.

    1993-01-01

    We discuss Galactic cosmic-ray (GCR) spallation production of Li, Be, and B in the early Galaxy with particular attention to the uncertainties in the predictions of this model. The observed correlation between the Be abundance and the metallicity in metal-poor Population II stars requires that Be was synthesized in the early Galaxy. We show that the observations and such Population II GCR synthesis of Be are quantitatively consistent with the big bang nucleosynthesis production of Li-7. We find that there is a nearly model independent lower bound to B/Be of about 7 for GCR synthesis. Recent measurements of B/Be about 10 in HD 140283 are in excellent agreement with the predictions of Population II GCR nucleosynthesis. Measurements of the boron abundance in additional metal-poor halo stars is a key diagnostic of the GCR spallation mechanism. We also show that Population II GCR synthesis can produce amounts of Li-6 which may be observed in the hottest halo stars.

  15. DESPIKING OF SPACECRAFT ENERGETIC PROTON FLUX TO STUDY GALACTIC COSMIC-RAY MODULATION

    SciTech Connect

    Qin, G.; Zhao, L.-L.; Chen, H.-C. E-mail: llzhao@spaceweather.ac.cn

    2012-06-20

    Galactic cosmic ray (GCR) is usually assumed as a stable 'background', with solar influence considered as a modulation. The violent solar energetic particle (SEP) events associated with solar activities change particle fluxes by several orders of magnitude in a few minutes. Thus, the flux observation of GCR provided by satellites may be heavily contaminated by spurious spikes due to SEPs, and that provided by ground-based neutron monitors (NMs) may be contaminated by the system error spikes and the ground level enhancement effect. To obtain the 'pure' background GCR flux for modulation research, the removal of multifarious spikes is necessary. In this article, we use a robust automatic despiking algorithm based on the Poincare map thresholding method provided by Goring and Nikora for 'purification' of the time-series GCR flux observations. We can show that the algorithm is good at cleaning up the heavily contaminated GCR intensity rates measured by both spacecraft and NMs without artificial parameters. In addition, using the algorithm to despike the spacecraft observations of relatively lower energetic proton flux, we get both 11 year and 27 day period cycles comparable to the much higher energy GCR flux data measured by the ground-based NMs.

  16. Heliospheric and geomagnetic modulation of galactic cosmic rays under quiet and disturbed interplanetary conditions during solar cycles 20-23

    NASA Astrophysics Data System (ADS)

    Chukwudi Okpala, Kingsley

    2015-08-01

    The modulation of galactic cosmic rays (GCR) within the heliosphere leads to a reduction in the GCR count rates during period of high solar activity and conversely. Data from three geomagnetic observatories and three Neutron monitors (in close proximity to the geomagnetic stations) have been studied. The monthly residuals of the geomagnetic field components with respect to quiet time conditions from these three stations have been computed and compared with the cosmic ray count rates. The modulations of the GCR during quiet and disturbed interplanetary conditions have been investigated with a view to better understand the role of the global merged interaction regions and intense magnetic fields to the GCR modulation. From first-order partial correlation, we found that removing the influence of the total IMF-B, (especially during quiet conditions) and the influence of SW dynamic pressure (during disturbed conditions) generally enhances the correlation of the residual geomagnetic field with the GCR significantly. The influence of the more subtle parameters like speed, Bz component and proton density were masked by these dominant parameters. Results from this work are important for the modeling of long term GCR variability.

  17. Computational and Genetic Reduction of a Cell Cycle to Its Simplest, Primordial Components

    PubMed Central

    Fumeaux, Coralie; Viollier, Patrick H.; Howard, Martin

    2013-01-01

    What are the minimal requirements to sustain an asymmetric cell cycle? Here we use mathematical modelling and forward genetics to reduce an asymmetric cell cycle to its simplest, primordial components. In the Alphaproteobacterium Caulobacter crescentus, cell cycle progression is believed to be controlled by a cyclical genetic circuit comprising four essential master regulators. Unexpectedly, our in silico modelling predicted that one of these regulators, GcrA, is in fact dispensable. We confirmed this experimentally, finding that ΔgcrA cells are viable, but slow-growing and elongated, with the latter mostly due to an insufficiency of a key cell division protein. Furthermore, suppressor analysis showed that another cell cycle regulator, the methyltransferase CcrM, is similarly dispensable with simultaneous gcrA/ccrM disruption ameliorating the cytokinetic and growth defect of ΔgcrA cells. Within the Alphaproteobacteria, gcrA and ccrM are consistently present or absent together, rather than either gene being present alone, suggesting that gcrA/ccrM constitutes an independent, dispensable genetic module. Together our approaches unveil the essential elements of a primordial asymmetric cell cycle that should help illuminate more complex cell cycles. PMID:24415923

  18. Despiking of energetic proton flux to study galactic cosmic ray modulation

    NASA Astrophysics Data System (ADS)

    Zhao, L.; Qin, G.; Chen, H.

    2011-12-01

    The solar influence on Galactic cosmic ray (GCR) flux can be generally described as the usually stable "background" modulation. The violent Solar Energetic Particle (SEP) events associated with solar activities can cause surging particle flux. Thus, the GCR flux observation from satellites may be heavily contaminated by spurious spikes due to SEPs. And spike may also arise in the long time series count rates data provided by ground-based neutron monitors, e.g., system glitch. To obtain the "pure" background GCR flux for modulation research, the removal of multifarious spikes is necessary. In this article, we present a robust automatic despiking algorithm based on Poincare map thresholding method to "purify" time-series GCR flux. The algorithm is effective and robust for detecting various types of spikes in the GCR count rates of neutron monitors. In addition, after despiking spacecraft observations of relatively lower energy energetic proton flux using our algorithm, we get both 11-year and 27-day period cycles comparable to the much higher energy GCR count rate data from the ground-based neutron monitors.

  19. Despiking of Spacecraft Energetic Proton Flux to Study Galactic Cosmic-Ray Modulation

    NASA Astrophysics Data System (ADS)

    Qin, G.; Zhao, L.-L.; Chen, H.-C.

    2012-06-01

    Galactic cosmic ray (GCR) is usually assumed as a stable "background," with solar influence considered as a modulation. The violent solar energetic particle (SEP) events associated with solar activities change particle fluxes by several orders of magnitude in a few minutes. Thus, the flux observation of GCR provided by satellites may be heavily contaminated by spurious spikes due to SEPs, and that provided by ground-based neutron monitors (NMs) may be contaminated by the system error spikes and the ground level enhancement effect. To obtain the "pure" background GCR flux for modulation research, the removal of multifarious spikes is necessary. In this article, we use a robust automatic despiking algorithm based on the Poincare map thresholding method provided by Goring and Nikora for "purification" of the time-series GCR flux observations. We can show that the algorithm is good at cleaning up the heavily contaminated GCR intensity rates measured by both spacecraft and NMs without artificial parameters. In addition, using the algorithm to despike the spacecraft observations of relatively lower energetic proton flux, we get both 11 year and 27 day period cycles comparable to the much higher energy GCR flux data measured by the ground-based NMs.

  20. Effects of Cutoffs on Galactic Cosmic-Ray Interactions in Solar-System Matter

    NASA Technical Reports Server (NTRS)

    Kim, K. J.; Reedy, R. C.; Masarik, J.

    2005-01-01

    The energetic particles in the galactic cosmic rays (GCR) induce many interactions in a variety of solar-system matter. Cosmogenic nuclides are used to study the histories of meteorites and lunar samples. Gamma rays and neutrons are used to map the compositions of planetary surfaces, such as Mars, the Moon, and asteroids. In almost all of these cases, the spectra of incident GCR particles are fairly similar, with only some modulation by the Sun over an 11-year cycle. Strong magnetic fields can seriously affect the energy spectrum of GCR particles hitting the surface of objects inside the magnetic fields. The Earth s geomagnetic field is strong enough that only GCR particles with magnetic rigidities above approx. 17 GV (a proton energy of approx. 17 GeV) reach the atmosphere over certain regions near the equator. This effect of removing lower-energy GCR particles is called a cutoff. The jovian magnetic fields are so strong that the fluxes of GCR particles hitting the 4 large Galilean satellites are similarly affected. The cutoff at Europa is estimated to be similar to or a little higher than at the Earth s equator.

  1. Implementing Badhwar-O'Neill Galactic Cosmic Ray Model for the Analysis of Space Radiation Exposure

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; O'Neill, Patrick M.; Slaba, Tony C.

    2014-01-01

    For the analysis of radiation risks to astronauts and planning exploratory space missions, accurate energy spectrum of galactic cosmic radiation (GCR) is necessary. Characterization of the ionizing radiation environment is challenging because the interplanetary plasma and radiation fields are modulated by solar disturbances and the radiation doses received by astronauts in interplanetary space are likewise influenced. A model of the Badhwar-O'Neill 2011 (BO11) GCR environment, which is represented by GCR deceleration potential theta, has been derived by utilizing all of the GCR measurements from balloons, satellites, and the newer NASA Advanced Composition Explorer (ACE). In the BO11 model, the solar modulation level is derived from the mean international sunspot numbers with time-delay, which has been calibrated with actual flight instrument measurements to produce better GCR flux data fit during solar minima. GCR fluxes provided by the BO11 model were compared with various spacecraft measurements at 1 AU, and further comparisons were made for the tissue equivalent proportional counters measurements at low Earth orbits using the high-charge and energy transport (HZETRN) code and various GCR models. For the comparison of the absorbed dose and dose equivalent calculations with the measurements by Radiation Assessment Detector (RAD) at Gale crater on Mars, the intensities and energies of GCR entering the heliosphere were calculated by using the BO11 model, which accounts for time-dependent attenuation of the local interstellar spectrum of each element. The BO11 model, which has emphasized for the last 24 solar minima, showed in relatively good agreement with the RAD data for the first 200 sols, but it was resulted in to be less well during near the solar maximum of solar cycle 24 due to subtleties in the changing heliospheric conditions. By performing the error analysis of the BO11 model and the optimization in reducing overall uncertainty, the resultant BO13 model corrects the fit at solar maxima as well as being accurate at solar minima. The BO13 model is implemented to the NASA Space Cancer Risk model for the assessment of radiation risks. Overall cumulative probability distribution of solar modulation parameters represents the percentile rank of the average interplanetary GCR environment, and the probabilistic radiation risks can be assessed for various levels of GCR environment to support mission design and operational planning for future manned space exploration missions.

  2. Galactic cosmic ray variations at the moon

    NASA Astrophysics Data System (ADS)

    Case, Anthony W.

    2011-05-01

    Galactic Cosmic Rays (GCR) are the predominant source of highly energetic particles in the inner heliosphere during solar quiet times. These particles are fully ionized atoms that are accelerated to near-relativistic speeds during events of extreme energy release throughout the Milky Way Galaxy and beyond. Some GCR particles eventually find their way to the outer edges of the heliosphere and a portion of those are able to propagate to 1 AU. GCR have sufficient energy to ionize atoms and molecules in the matter that they impact, causing radiation damage to both robotic and biologic materials. Understanding the flux and spectrum of GCR is of great importance to future robotic and human explorers venturing beyond low-Earth orbit. In this dissertation, we use the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument along with modeling efforts to study a variety of phenomena that can influence the energetic particle flux in the near-Moon environment, including Interplanetary Coronal Mass Ejections (ICMEs), Corotating Interaction Regions (CIRs) and the Earth's magnetotail. As part of this study, the CRaTER instrument and its calibration are discussed in detail. A new model is developed to better predict the transit times of Interplanetary Coronal Mass Ejections and the associated drops in GCR flux called Forbush decreases. This model could provide a more accurate estimate of an ICME's arrival time within hours of ejection from the Sun. An important model discrepancy is resolved by using the CRaTER instrument to measure GCR while the Moon is in the Earth's magnetotail. Previous studies that predicted shielding of GCR by the magnetotail are disproven; we find no evidence for a drop in GCR, intensity as a result of passage through the magnetotail. We use the CRaTER instrument to investigate step-like durable decreases in GCR flux with time. We find that these decreases occurred when CIRs convected past the observing spacecraft shortly after solar minimum, presumably caused by the more effective shielding provided by the outward propagating magnetic structures. A change in the proton linear energy transfer spectrum is observed in conjunction with the GCR flux decrease.

  3. Badhwar-O'Neill 2011 Galactic Cosmic Ray Model Update and Future Improvements

    NASA Technical Reports Server (NTRS)

    O'Neill, Pat M.; Kim, Myung-Hee Y.

    2014-01-01

    The Badhwar-O'Neill Galactic Cosmic Ray (GCR) Model based on actual GCR measurements is used by deep space mission planners for the certification of microelectronic systems and the analysis of radiation health risks to astronauts in space missions. The BO GCR Model provides GCR flux in deep space (outside the earth's magnetosphere) for any given time from 1645 to present. The energy spectrum from 50 MeV/n - 20 GeV/n is provided for ions from hydrogen to uranium. This work describes the most recent version of the BO GCR model (BO'11). BO'11 determined the GCR flux at a given time applying an emperical time delay function to past sunspot activity. We describe the GCR measurement data used in the BO'11 update - modern data from BESS, PAMELA, CAPRICE, and ACE emphasized more than the older balloon data used for the previous BO model (BO'10). We look at the GCR flux for the last 24 solar minima and show how much greater the flux was for the cycle 24 minimum in 2010. The BO'11 Model uses the traditional, steady-state Fokker-Planck differential equation to account for particle transport in the heliosphere due to diffusion, convection, and adiabatic deceleration. It assumes a radially symmetrical diffusion coefficient derived from magnetic disturbances caused by sunspots carried outward by a constant solar wind. A more complex differential equation is now being tested to account for particle transport in the heliosphere in the next generation BO model. This new model is time-dependent (no longer a steady state model). In the new model, the dynamics and anti-symmetrical features of the actual heliosphere are accounted for so emperical time delay functions will no longer be required. The new model will be capable of simulating the more subtle features of modulation - such as the Sun's polarity and modulation dependence on gradient and curvature drift. This improvement is expected to significantly improve the fidelity of the BO GCR model. Preliminary results of its performance will be presented.

  4. Neutron yields and effective doses produced by Galactic Cosmic Ray interactions in shielded environments in space.

    PubMed

    Heilbronn, Lawrence H; Borak, Thomas B; Townsend, Lawrence W; Tsai, Pi-En; Burnham, Chelsea A; McBeth, Rafe A

    2015-11-01

    In order to define the ranges of relevant neutron energies for the purposes of measurement and dosimetry in space, we have performed a series of Monte Carlo transport model calculations that predict the neutron field created by Galactic Cosmic Ray interactions inside a variety of simple shielding configurations. These predictions indicate that a significant fraction of the neutron fluence and neutron effective dose lies in the region above 20 MeV up to several hundred MeV. These results are consistent over thicknesses of shielding that range from very thin (2.7 g/cm(2)) to thick (54 g/cm(2)), and over both shielding materials considered (aluminum and water). In addition to these results, we have also investigated whether simplified Galactic Cosmic Ray source terms can yield predictions that are equivalent to simulations run with a full GCR source term. We found that a source using a GCR proton and helium spectrum together with a scaled oxygen spectrum yielded nearly identical results to a full GCR spectrum, and that the scaling factor used for the oxygen spectrum was independent of shielding material and thickness. Good results were also obtained using a GCR proton spectrum together with a scaled helium spectrum, with the helium scaling factor also independent of shielding material and thickness. Using a proton spectrum alone was unable to reproduce the full GCR results. PMID:26553642

  5. Depth-dose equivalent relationship for cosmic rays at various solar minima

    NASA Technical Reports Server (NTRS)

    Badhwar, G. D.; Cucinotta, F. A.; O'Neill, P. M.

    1993-01-01

    Galactic cosmic rays (GCR) pose a serious radiation hazard for long-duration missions. In designing a lunar habitat or a Mars transfer vehicle, the radiation exposure determines the GCR shielding thickness, and hence the weight of spacecraft. Using the spherically symmetric diffusion theory of the solar modulation of GCR, and data on the differential energy spectra of H, He, O, and Fe, from 1965 to 1989, it has been shown that (1) the flux is determined by the diffusion parameter which is a function of the time in the solar cycle, and (2) the fluxes in the 1954 and 1976-1977 solar minima were similar and higher than those in 1965. In this paper, we have extended the spherical solar modulation theory back to 1954. The 1954-1955 GCR flux was nearly the same as that from 1976 to 1977; the 1965 flux values were nearly the same as those in 1986. Using this theory we have obtained the GCR spectra for all the nuclei, and calculated the depth dose as a function of Al thickness. It is shown that the shielding required to stay below 0.5 Sv is 17.5 -3/+8 g/sq cm of Al, and 9 -1.5/+5 g/sq cm to stay below 0.6 Sv. The calculated dose equivalent using the ICRP 60 values for quality factors is about 15 percent higher than that calculated using the ICRP 26 value.

  6. Evaluating Shielding Effectiveness for Reducing Space Radiation Cancer Risks

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Kim, Myung-Hee Y.; Ren, Lei

    2007-01-01

    We discuss calculations of probability distribution functions (PDF) representing uncertainties in projecting fatal cancer risk from galactic cosmic rays (GCR) and solar particle events (SPE). The PDF s are used in significance tests of the effectiveness of potential radiation shielding approaches. Uncertainties in risk coefficients determined from epidemiology data, dose and dose-rate reduction factors, quality factors, and physics models of radiation environments are considered in models of cancer risk PDF s. Competing mortality risks and functional correlations in radiation quality factor uncertainties are treated in the calculations. We show that the cancer risk uncertainty, defined as the ratio of the 95% confidence level (CL) to the point estimate is about 4-fold for lunar and Mars mission risk projections. For short-stay lunar missions (<180 d), SPE s present the most significant risk, however one that is mitigated effectively by shielding, especially for carbon composites structures with high hydrogen content. In contrast, for long duration lunar (>180 d) or Mars missions, GCR risks may exceed radiation risk limits, with 95% CL s exceeding 10% fatal risk for males and females on a Mars mission. For reducing GCR cancer risks, shielding materials are marginally effective because of the penetrating nature of GCR and secondary radiation produced in tissue by relativistic particles. At the present time, polyethylene or carbon composite shielding can not be shown to significantly reduce risk compared to aluminum shielding based on a significance test that accounts for radiobiology uncertainties in GCR risk projection.

  7. Breast Cancer by Age at Diagnosis in the Gharbiah, Egypt, Population-Based Registry Compared to the United States Surveillance, Epidemiology, and End Results Program, 2004–2008

    PubMed Central

    Schlichting, Jennifer A.; Soliman, Amr S.; Schairer, Catherine; Harford, Joe B.; Hablas, Ahmed; Ramadan, Mohamed; Seifeldin, Ibrahim; Merajver, Sofia D.

    2015-01-01

    Objective. Although breast cancers (BCs) in young women often display more aggressive features, younger women are generally not screened for early detection. It is important to understand the characteristics of young onset breast cancer to increase awareness in this population. This analysis includes all ages, with emphasis placed on younger onset BC in Egypt as compared to the United States. Methods. BC cases in the Gharbiah cancer registry (GCR), Egypt, were compared to those in the Surveillance, Epidemiology, and End Results (SEER) database. This analysis included 3,819 cases from the GCR and 273,019 from SEER diagnosed 2004–2008. Results. GCR cases were diagnosed at later stages, with <5% diagnosed at Stage I and 12% diagnosed at Stage IV. 48% of all SEER cases were diagnosed at Stage I, dropping to 30% among those ≤40. Significant differences in age, tumor grade, hormone receptor status, histology, and stage exist between GCR and SEER BCs. After adjustment, GCR cases were nearly 45 times more likely to be diagnosed at stage III and 16 times more likely to be diagnosed at stage IV than SEER cases. Conclusions. Future research should examine ways to increase literacy about early detection and prompt therapy in young cases. PMID:26495294

  8. Tumor Necrosis Factor Inhibits Glucocorticoid Receptor Function in Mice

    PubMed Central

    Van Bogaert, Tom; Vandevyver, Sofie; Dejager, Lien; Van Hauwermeiren, Filip; Pinheiro, Iris; Petta, Ioanna; Engblom, David; Kleyman, Anna; Schütz, Günther; Tuckermann, Jan; Libert, Claude

    2011-01-01

    As glucocorticoid resistance (GCR) and the concomitant burden pose a worldwide problem, there is an urgent need for a more effective glucocorticoid therapy, for which insights into the molecular mechanisms of GCR are essential. In this study, we addressed the hypothesis that TNFα, a strong pro-inflammatory mediator in numerous inflammatory diseases, compromises the protective function of the glucocorticoid receptor (GR) against TNFα-induced lethal inflammation. Indeed, protection of mice by dexamethasone against TNFα lethality was completely abolished when it was administered after TNFα stimulation, indicating compromised GR function upon TNFα challenge. TNFα-induced GCR was further demonstrated by impaired GR-dependent gene expression in the liver. Furthermore, TNFα down-regulates the levels of both GR mRNA and protein. However, this down-regulation seems to occur independently of GC production, as TNFα also resulted in down-regulation of GR levels in adrenalectomized mice. These findings suggest that the decreased amount of GR determines the GR response and outcome of TNFα-induced shock, as supported by our studies with GR heterozygous mice. We propose that by inducing GCR, TNFα inhibits a major brake on inflammation and thereby amplifies the pro-inflammatory response. Our findings might prove helpful in understanding GCR in inflammatory diseases in which TNFα is intimately involved. PMID:21646349

  9. Interstellar propagation and electron capture processes of galactic cosmic ray heavy ions in space

    NASA Technical Reports Server (NTRS)

    Miltra, B.; Biswas, S.; Goswami, J. N.

    1995-01-01

    The new information on galactic cosmic rays (GCR) derived from the Spacelab-3 cosmic ray experiment 'Anuradha' shows that at 25-125 MeV/N GCR sub-iron and iron (Z = 21-28) particles consists of a mixture of partially ionized and fully ionized ions. Computation of electron capture and loss cross sections in hydrogen in 1-50 MeV/N energy range are made for Fe, Cr, Ti and Ni. From these it is concluded that: (1) these GCR particles must have captured orbital electrons at energies of about 1-5 MeV/N and (2) these particles are then reaccelerated to 300-500 MeV/N most probably in interstellar medium by collision with SNR shock fronts. Some reacceleration may take place also in heliospheric boundary region. It is suggested that these observations of partially ionized GCR ions of about 100 MeV/N in Spacelab-3 provide a direct evidence of reacceleration of GCR.

  10. Study the effect of gray component replacement level on reflectance spectra and color reproduction accuracy

    NASA Astrophysics Data System (ADS)

    Spiridonov, I.; Shopova, M.; Boeva, R.

    2013-03-01

    The aim of this study is investigation of gray component replacement (GCR) levels on reflectance spectrum for different overprints of the inks and color reproduction accuracy. The most commonly implemented method in practice for generation of achromatic composition is gray component replacement (GCR). The experiments in this study, have been performed in real production conditions with special test form generated by specialized software. The measuring of reflection spectrum of printed colors, gives a complete conception for the effect of different gray component replacement levels on color reproduction accuracy. For better data analyses and modeling of processes, we have calculated (converted) the CIEL*a*b* color coordinates from the reflection spectra data. The assessment of color accuracy by using different GCR amount has been made by calculation of color difference ΔE* ab. In addition for the specific printing conditions we have created ICC profiles with different GCR amounts. A comparison of the color gamuts has been performed. For a first time a methodology is implemented for examination and estimation of effect of GCR levels on color reproduction accuracy by studying a big number of colors in entire visible spectrum. Implementation in practice of the results achieved in this experiment, will lead to improved gray balance and better color accuracy. Another important effect of this research is reduction of financial costs of printing production by decreasing of ink consumption, indirect reduction of emissions during the manufacture of inks and facilitates the process of deinking during the recycling paper.

  11. Nuclide production by primary cosmic-ray protons

    SciTech Connect

    Reedy, R.C.

    1986-01-01

    The production rates of cosmogenic nuclides in the solar system and in interstellar space were calculated for the primary protons in the galactic and solar cosmic rays. At 1 AU, the long-term average fluxes of solar protons usually produce many more atoms of a cosmogenic nuclide than the primary protons in the galactic cosmic rays (GCR), the exceptions being nuclides made only by high-energy reactions (like /sup 10/Be). Because the particle fluxes inside meteorites and other large objects in space include many secondary neutrons, the production rates are much higher and ratios inside large objects are often very different from those by just the primary GCR protons in small objects. The production rates of cosmogenic nuclides are calculated to vary by about factors of 2.5 during at typical 11-year solar cycle, in agreement with measurements of short-lived radionuclides in recently fallen meteorites. The production of cosmogenic nuclides by the GCR particles outside the heliosphere is higher than that by the modulated GCR primaries normally in the solar system. However, there is considerable uncertainty in the fluxes of interstellar protons and, therefore, in the production rates of cosmogenic nuclides in interstellar space. Production rates and ratios for cosmogenic nuclides would be able to identify particles that were small in space or that were exposed to an unmodulated spectrum of GCR particles. 25 refs., 2 figs., 2 tabs.

  12. Modeling of the recurrent Forbush effect of the galactic cosmic ray intensity and comparison with the experimental data

    NASA Astrophysics Data System (ADS)

    Wawrzynczak, A.; Alania, M. V.

    We developed a new three dimensional 3-D steady-state model of the recurrent Forbush effect of the galactic cosmic ray GCR intensity using Parker s transport equation New code for the solution of the transport equation is realized by C and needs less time for computations than the FORTRAN variant Convection diffusion drift and energy change of the GCR particles in the diverged solar wind are taken into account in the modeling Changes of the strength of the interplanetary magnetic field IMF and the power spectral density PSD of the IMF s turbulence in the range of frequencies sim 10 -6 -- 10 -5 Hz versus the radial distance heliolatitudes and heliolongitudes are the sources of the recurrent Forbush effect of the GCR intensity The state of this range of the frequencies sim 10 -6 -- 10 -5 Hz of the IMF s turbulence is responsible for the intensive diffusion of the GCR particles of the energy 5-50 GeV responding by neutron monitors and for a peculiarities of the rigidity spectrum of the Forbush effect Results of the modeling calculations time profile amplitude rigidity spectrum are compatible with the experimental data of the Forbush effects of the GCR intensity observed by neutron monitors in the positive A 0 and in the negative A 0 periods of solar magnetic cycle

  13. Search for cosmogenic Ar-42 in meteorites

    NASA Astrophysics Data System (ADS)

    Cini Castagnoli, G.; Cane, D.; Taricco, C.; Bhandari, N.

    2003-04-01

    We have evidence for decreasing galactic cosmic ray (GCR) flux in the past 3 centuries by a factor about two [1]. The measurements of the activity of cosmogenic 44Ti (T1/2 = 59.2 y) produced by GCR in stony meteorites that fell during the last two centuries are in good agreement with the calculated values and validate the decreasing trend of GCR flux. The measurements were obtained by an hyperpure (372 cm3) Ge-NaI(Tl) spectrometer operating in the Monte dei Cappuccini laboratory in Torino[2]. To further improve upon statistical precision of 44Ti data and also to be able to measure the 42Ar (T1/2 = 33 y) which is produced in even smaller amounts by GCR in meteorites, we have set up in the same laboratory a larger (581 cm3) hyperpure Ge detector operating in coincidence with a 100 kg NaI(Tl) crystal assembly. This should enable us to confirm the above results about GCR variations. We wish to acknowledge our deep gratitude to professor Bonino, deceased on September 29, 2002, to whom the assemblage of the new equipment is due. [1] G. Bonino, G. Cini Castagnoli, D. Cane, C. Taricco and N. Bhandari,Proc. XXVII Intern. Cosmic Ray Conf. (Hamburg, 2001) 3769-3772. [2] Bonino G., Cini Castagnoli G., Cane D., Taricco C., Bhandari N, textit {34th COSPAR Sci. Ass. Houston 2002 (Adv. Space Res.)}, in press

  14. Stratospheric polar vortex as a possible reason for temporal variations of solar activity and galactic cosmic ray effects on the lower atmosphere circulation

    NASA Astrophysics Data System (ADS)

    Veretenenko, S.; Ogurtsov, M.

    2014-12-01

    Possible reasons for the temporal instability of long-term effects of solar activity (SA) and galactic cosmic ray (GCR) variations on the lower atmosphere circulation were studied. It was shown that the detected earlier ∼60-year oscillations of the amplitude and sign of SA/GCR effects on the troposphere pressure at high and middle latitudes (Veretenenko and Ogurtsov, Adv.Space Res., 2012) are closely related to the state of a cyclonic vortex forming in the polar stratosphere. The intensity of the vortex was found to reveal a roughly 60-year periodicity affecting the evolution of the large-scale atmospheric circulation and the character of SA/GCR effects. An intensification of both Arctic anticyclones and mid-latitudinal cyclones associated with an increase of GCR fluxes at minima of the 11-year solar cycles is observed in the epochs of a strong polar vortex. In the epochs of a weak polar vortex SA/GCR effects on the development of baric systems at middle and high latitudes were found to change the sign. The results obtained provide evidence that the mechanism of solar activity and cosmic ray influences on the lower atmosphere circulation involves changes in the evolution of the stratospheric polar vortex.

  15. The role of the stratospheric polar vortex in solar activity and cosmic ray effects on the lower atmosphere circulation

    NASA Astrophysics Data System (ADS)

    Veretenenko, Svetlana; Ogurtsov, Maxim

    2012-07-01

    Possible reasons for a temporal instability of long-term effects of solar activity (SA) and galactic cosmic ray (GCR) variations on the lower atmosphere circulation were studied. It was shown that the detected earlier ˜60-year oscillations of the amplitude and sign of SA/GCR effects on the troposphere pressure at high and middle latitudes (Veretenenko and Ogurtsov, 2012) were closely related to the state of a cyclonic vortex forming in the polar stratosphere. An intensity of the vortex was found to reveal a roughly 60-year periodicity affecting the evolution of the large-scale atmospheric circulation and, then, the character of SA/GCR effects. An intensification of polar anticyclones and mid-latitudinal cyclones associated with an increase of GCR fluxes at minima of the 11-year solar cycles is observed in the epochs of a strong polar vortex. In the epochs of a weak polar vortex SA/GCR effects on the development of baric systems at middle and high latitudes were found to change the sign. The results obtained provide evidence that the mechanism of solar activity and cosmic ray influences on the lower atmosphere circulation involves changes in the evolution of the stratospheric polar vortex. Veretenenko S.V., Ogurtsov M.G. Regional and temporal variability of solar activity and galactic cosmic ray effects on the lower atmosphere circulation. Adv. Space Res., 49, 770-783, 2012.

  16. Movement patterns of wintering lesser scaup in Grand Calumet River - Indiana Harbor Canal, Indiana

    USGS Publications Warehouse

    Custer, Christine M.; Custer, T.W.; Sparks, D.W.; Hines, Randy K.; Kochanny, C.O.

    1996-01-01

    Lesser scaup (Aythya affinis) winter in the Grand Calumet River-Indiana Harbor Canal (GCR-IHC) drainage into southern Lake Michigan, a polluted oasis in the highly urban and industrial corridor of northern Illinois and Indiana. The GCR-IHC is an important wintering area for lesser scaup in northwestern Indiana, especially after Lake Michigan freezes, because of the lack of other wildlife habitat in the area. We investigated the feeding and movement patterns of these wintering lesser scaup to better understand the ecological significance of this area to wintering waterfowl and to interpret contaminant levels in these lesser scaup. We implanted radio transmitters in 20 individuals in January 1994 and tracked them until early March 1994. Four lesser scaup disappeared and four died within the first 2 weeks after implantation; 12 lesser scaup remained in the GCR-IHC for the next 6-7 weeks. Individual radio-marked scaup (n = 12) were located in the GCR-IHC on an average of 62.2% (extreme values = 25-87%) of the searches. No radio-marked lesser scaup were located outside the GCR-IHC. Lesser scaup were feeding during 23% of the radio fixes.

  17. Super-TIGER: A Balloon-Borne Instrument to Probe Galactic Cosmic Ray Origins

    NASA Astrophysics Data System (ADS)

    Rauch, Brian

    2012-07-01

    Super-TIGER (Super Trans-Iron Galactic Element Recorder) is a balloon-borne instrument under construction for a long-duration flight from Antarctica in 2012. It is designed to measure the relative abundances of the ultra-heavy (UH) Galactic cosmic rays (GCR) with individual-element resolution from _{30}Zn to _{42}Mo and make exploratory measurements through _{56}Ba, as well as the energy spectra of the GCR from _{10}Ne to _{29}Cu between 0.8 and 10 GeV/nucleon. The UH measurements will test the OB association origin model of the GCR, as well as the model of preferential acceleration of refractory elements. The GCR spectrum measurements will probe for microquasars or other sources that could superpose spectral features. Super-TIGER is a ˜ 4 × larger evolution of the preceding TIGER instrument, and is comprised of two independent modules with a total area of 5.4 m^{2}. A combination of plastic scintillation detectors, acrylic and silica-aerogel Cherenkov detectors, and scintillating fiber hodoscopes are used to resolve particle charge, kinetic energy per nucleon, and trajectory. Refinements in the Super-TIGER design over TIGER, including reduced material in the beam, give it a collecting power that is ˜ 6.4× larger. This paper will report on the instrument development status, the expected flight performance, and the scientific impact of the anticipated Super-TIGER GCR measurements. This research was supported by NASA under Grant NNX09AC17G

  18. Simulated Response of a Tissue-equivalent Proportional Counter on the Surface of Mars.

    PubMed

    Northum, Jeremy D; Guetersloh, Stephen B; Braby, Leslie A; Ford, John R

    2015-10-01

    Uncertainties persist regarding the assessment of the carcinogenic risk associated with galactic cosmic ray (GCR) exposure during a mission to Mars. The GCR spectrum peaks in the range of 300(-1) MeV n to 700 MeV n(-1) and is comprised of elemental ions from H to Ni. While Fe ions represent only 0.03% of the GCR spectrum in terms of particle abundance, they are responsible for nearly 30% of the dose equivalent in free space. Because of this, radiation biology studies focusing on understanding the biological effects of GCR exposure generally use Fe ions. Acting as a thin shield, the Martian atmosphere alters the GCR spectrum in a manner that significantly reduces the importance of Fe ions. Additionally, albedo particles emanating from the regolith complicate the radiation environment. The present study uses the Monte Carlo code FLUKA to simulate the response of a tissue-equivalent proportional counter on the surface of Mars to produce dosimetry quantities and microdosimetry distributions. The dose equivalent rate on the surface of Mars was found to be 0.18 Sv y(-1) with an average quality factor of 2.9 and a dose mean lineal energy of 18.4 keV μm(-1). Additionally, albedo neutrons were found to account for 25% of the dose equivalent. It is anticipated that these data will provide relevant starting points for use in future risk assessment and mission planning studies. PMID:26313586

  19. The Development of Materials for Structures and Radiation Shielding in Aerospace

    NASA Technical Reports Server (NTRS)

    Kiefer, Richard L.; Orwoll, Robert A.

    2001-01-01

    Polymeric materials on space vehicles and high-altitude aircraft win be exposed to highly penetrating radiations. These radiations come from solar flares and galactic cosmic rays (GCR). Radiation from solar flares consists primarily of protons with energies less than 1 GeV. On the other hand, GCR consist of nuclei with energies as high as 10(exp 10) GeV. Over 90% of the nuclei in GCR are protons and alpha particles, however there is a small but significant component of particles with atomic numbers greater than ten. Particles with high atomic number (Z) and high energy interact with very high specific ionization and thus represent a serious hazard for humans and electronic equipment on a spacecraft or on high-altitude commercial aircraft (most importantly for crew members who would have long exposures). Neutrons generated by reactions with the high energy particles also represent a hazard both for humans and electronic equipment.

  20. Stopping powers and cross sections due to two-photon processes in relativistic nucleus-nucleus collision

    NASA Technical Reports Server (NTRS)

    Cheung, Wang K.; Norbury, John W.

    1992-01-01

    The radiation dose received from high energy galactic cosmic rays (GCR) is a limiting factor in the design of long duration space flights and the building of lunar and martian habitats. It is of vital importance to have an accurate understanding of the interactions of GCR in order to assess the radiation environment that the astronauts will be exposed to. Although previous studies have concentrated on the strong interaction process in GCR, there are also very large effects due to electromagnetic (EM) interactions. In this report we describe our first efforts at understanding these EM production processes due to two-photon collisions. More specifically, we shall consider particle production processes in relativistic heavy ion collisions (RHICs) through two-photon exchange.

  1. Low-energy break in the spectrum of Galactic cosmic rays.

    PubMed

    Neronov, A; Semikoz, D V; Taylor, A M

    2012-02-01

    Measurements of the low-energy spectrum of Galactic cosmic rays (GCRs) by detectors on or near Earth are affected by solar modulation. To overcome this difficulty, we consider nearby molecular clouds as GCR detectors outside the Solar System. Using γ-ray observations of the clouds by the Fermi telescope, we derive the spectrum of GCRs in the clouds from the observed γ-ray emission spectrum. We find that the GCR spectrum has a low-energy break with the spectral slope hardening by ΔΓ=1.1±0.3 at an energy of E=9±3  GeV. Detection of a low-energy break enables a measurement of GCR energy density in the interstellar space U=0.9±0.3  eV/cm{3}. PMID:22400923

  2. Cellular track model of biological damage to mammalian cell cultures from galactic cosmic rays

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Katz, Robert; Wilson, John W.; Townsend, Lawrence W.; Nealy, John E.; Shinn, Judy L.

    1991-01-01

    The assessment of biological damage from the galactic cosmic rays (GCR) is a current interest for exploratory class space missions where the highly ionizing, high-energy, high-charge ions (HZE) particles are the major concern. The relative biological effectiveness (RBE) values determined by ground-based experiments with HZE particles are well described by a parametric track theory of cell inactivation. Using the track model and a deterministic GCR transport code, the biological damage to mammalian cell cultures is considered for 1 year in free space at solar minimum for typical spacecraft shielding. Included are the effects of projectile and target fragmentation. The RBE values for the GCR spectrum which are fluence-dependent in the track model are found to be more severe than the quality factors identified by the International Commission on Radiological Protection publication 26 and seem to obey a simple scaling law with the duration period in free space.

  3. Overview of on-board measurements during solar storm periods.

    PubMed

    Beck, P; Dyer, C; Fuller, N; Hands, A; Latocha, M; Rollet, S; Spurný, F

    2009-10-01

    Radiation exposure of aircraft crew caused by cosmic radiation is regulated in Europe by the European Community Council Directive 96/29/EURATOM and implemented into law in almost every country of the European Union. While the galactic cosmic radiation (GCR) leads on average to an exposure of about 3 mSv per year, solar cosmic radiation can lead to 1 mSv per one subsonic flight during solar storm periods. Compared to GCR, solar cosmic radiation shows a much softer proton spectrum but with a larger contribution of several orders of magnitude. This is the reason for the large radiation exposure in high northern and southern geographic latitudes during solar particle events. Here an overview of active radiation in-flight measurements undertaken during solar storms is given. In particular, tissue-equivalent proportional counter on-board measurements are shown and the radiation quality during solar storm periods with that for GCR is compared. PMID:19825832

  4. Experimental Plans for Subsystems of a Shock Wave Driven Gas Core Reactor

    NASA Technical Reports Server (NTRS)

    Kazeminezhad, F.; Anghai, S.

    2008-01-01

    This Contractor Report proposes a number of plans for experiments on subsystems of a shock wave driven pulsed magnetic induction gas core reactor (PMI-GCR, or PMD-GCR pulsed magnet driven gas core reactor). Computer models of shock generation and collision in a large-scale PMI-GCR shock tube have been performed. Based upon the simulation results a number of issues arose that can only be addressed adequately by capturing experimental data on high pressure (approx.1 atmosphere or greater) partial plasma shock wave effects in large bore shock tubes ( 10 cm radius). There are three main subsystems that are of immediate interest (for appraisal of the concept viability). These are (1) the shock generation in a high pressure gas using either a plasma thruster or pulsed high magnetic field, (2) collision of MHD or gas dynamic shocks, their interaction time, and collision pile-up region thickness, and (3) magnetic flux compression power generation (not included here).

  5. Cycling Changes in the Amplitudes of the 27-Day Variation of the Galactic Cosmic Ray Intensity

    NASA Astrophysics Data System (ADS)

    Gil, A.; Alania, M. V.

    2012-06-01

    We study quasi-periodical changes in the amplitudes of the 27-day variation of the galactic cosmic ray (GCR) intensity, and the parameters of solar wind and solar activity. We have recently found quasi-periodicity of three to four Carrington rotation periods (3 - 4 CRP) in the amplitudes of the 27-day variation of the GCR intensity (Gil and Alania in J. Atmos. Solar-Terr. Phys. 73, 294, 2011). A similar recurrence is recognized in parameters of solar activity (sunspot number, solar radio flux) and solar wind (components of the interplanetary magnetic field, solar wind velocity). We believe that the 3 - 4 CRP periodicity, among other periodicities, observed in the amplitudes of the 27-day variation of the GCR intensity is caused by a specific cycling structure of the Sun's magnetic field, which may originate from the turbulent nature of the solar dynamo.

  6. A genetic network that suppresses genome rearrangements in Saccharomyces cerevisiae and contains defects in cancers.

    PubMed

    Putnam, Christopher D; Srivatsan, Anjana; Nene, Rahul V; Martinez, Sandra L; Clotfelter, Sarah P; Bell, Sara N; Somach, Steven B; E S de Souza, Jorge; Fonseca, André F; de Souza, Sandro J; Kolodner, Richard D

    2016-01-01

    Gross chromosomal rearrangements (GCRs) play an important role in human diseases, including cancer. The identity of all Genome Instability Suppressing (GIS) genes is not currently known. Here multiple Saccharomyces cerevisiae GCR assays and query mutations were crossed into arrays of mutants to identify progeny with increased GCR rates. One hundred eighty two GIS genes were identified that suppressed GCR formation. Another 438 cooperatively acting GIS genes were identified that were not GIS genes, but suppressed the increased genome instability caused by individual query mutations. Analysis of TCGA data using the human genes predicted to act in GIS pathways revealed that a minimum of 93% of ovarian and 66% of colorectal cancer cases had defects affecting one or more predicted GIS gene. These defects included loss-of-function mutations, copy-number changes associated with reduced expression, and silencing. In contrast, acute myeloid leukaemia cases did not appear to have defects affecting the predicted GIS genes. PMID:27071721

  7. Revised Production Rates for Na-22 and Mn-54 in Meteorites Using Cross Sections Measured for Neutron-induced Reactions

    NASA Technical Reports Server (NTRS)

    Sisterson, J. M.; Kim, K. J.; Reedy, R. C.

    2004-01-01

    The interactions of galactic cosmic rays (GCR) with extraterrestrial bodies produce small amounts of radionuclides and stable isotopes. The production rates of many relatively short-lived radionuclides, including 2.6-year Na-22 and 312-day Mn-54, have been measured in several meteorites collected very soon after they fell. Theoretical models used to calculate production rates for comparison with the measured values rely on input data containing good cross section measurements for all relevant reactions. Most GCR particles are protons, but secondary neutrons make most cosmogenic nuclides. Calculated production rates using only cross sections for proton-induced reactions do not agree well with measurements. One possible explanation is that the contribution to the production rate from reactions initiated by secondary neutrons produced in primary GCR interactions should be included explicitly. This, however, is difficult to do because so few of the relevant cross sections for neutron-induced reactions have been measured.

  8. Radiation shielding requirements for manned deep space missions

    SciTech Connect

    Santoro, R.T.; Ingersoll, D.T.

    1991-04-01

    Galactic cosmic rays (GCR) and, particularly, solar flares (SF) constitute the major radiation hazards in deep space. The dose to astronauts from these radiation sources and the shielding required to mitigate its effect during a 480 day Mars mission is estimated here for a simplistic spacecraft geometry. The intent is to ball park'' the magnitude of the doses for the constant GCR background and for SF's that occur randomly during the mission. The spacecraft shielding and dose data are given only for primary GCR and SF radiation, recognizing that secondary particles produced by primary particle reactions in the spacecraft and High Z-High Energy particles will also contribute to the dose suffered by the astronauts. 22 refs., 7 figs., 2 tabs.

  9. A genetic network that suppresses genome rearrangements in Saccharomyces cerevisiae and contains defects in cancers

    PubMed Central

    Putnam, Christopher D.; Srivatsan, Anjana; Nene, Rahul V.; Martinez, Sandra L.; Clotfelter, Sarah P.; Bell, Sara N.; Somach, Steven B.; E.S. de Souza, Jorge; Fonseca, André F.; de Souza, Sandro J.; Kolodner, Richard D.

    2016-01-01

    Gross chromosomal rearrangements (GCRs) play an important role in human diseases, including cancer. The identity of all Genome Instability Suppressing (GIS) genes is not currently known. Here multiple Saccharomyces cerevisiae GCR assays and query mutations were crossed into arrays of mutants to identify progeny with increased GCR rates. One hundred eighty two GIS genes were identified that suppressed GCR formation. Another 438 cooperatively acting GIS genes were identified that were not GIS genes, but suppressed the increased genome instability caused by individual query mutations. Analysis of TCGA data using the human genes predicted to act in GIS pathways revealed that a minimum of 93% of ovarian and 66% of colorectal cancer cases had defects affecting one or more predicted GIS gene. These defects included loss-of-function mutations, copy-number changes associated with reduced expression, and silencing. In contrast, acute myeloid leukaemia cases did not appear to have defects affecting the predicted GIS genes. PMID:27071721

  10. The role of mediastinal adipose tissue 11β-hydroxysteroid d ehydrogenase type 1 and glucocorticoid expression in the development of coronary atherosclerosis in obese patients with ischemic heart disease

    PubMed Central

    2012-01-01

    Background Visceral fat deposition and its associated atherogenic complications are mediated by glucocorticoids. Cardiac visceral fat comprises mediastinal adipose tissue (MAT) and epicardial adipose tissue (EAT), and MAT is a potential biomarker of risk for obese patients. Aim Our objective was to evaluate the role of EAT and MAT 11beta-hydroxysteroid dehydrogenase type 1 (11β-HSD-1) and glucocorticoid receptor (GCR) expression in comparison with subcutaneous adipose tissue (SAT) in the development of coronary atherosclerosis in obese patients with coronary artery disease (CAD), and to assess their correlations with CD68 and fatty acids from these tissues. Methods and results Expression of 11β-HSD-1 and GCR was measured by qRT-PCR in EAT, MAT and SAT of thirty-one obese patients undergoing coronary artery bypass grafting due to CAD (obese CAD group) and sixteen obese patients without CAD undergoing heart valve surgery (controls). 11β-HSD-1 and GCR expression in MAT were found to be significantly increased in the obese CAD group compared with controls (p < 0.05). In the obese CAD group, 11β-HSD-1 and GCR mRNA levels were strongly correlated in MAT. Stearidonic acid was significantly increased in EAT and MAT of the obese CAD group and arachidonic acid was significantly expressed in MAT of the obese male CAD group (p < 0.05). Conclusions We report for the first time the increased expression of 11β-HSD-1 and GCR in MAT compared with EAT and SAT, and also describe the interrelated effects of stearidonic acid, HOMA-IR, plasma cortisol and GCR mRNA levels, explaining 40.2% of the variance in 11β-HSD-1 mRNA levels in MAT of obese CAD patients. These findings support the hypothesis that MAT contributes locally to the development of coronary atherosclerosis via glucocorticoid action. PMID:23009206

  11. Occurrence of Antimicrobial-Resistant Escherichia coli and Salmonella enterica in the Beef Cattle Production and Processing Continuum

    PubMed Central

    Agga, Getahun E.; Bosilevac, Joseph M.; Brichta-Harhay, Dayna M.; Shackelford, Steven D.; Wang, Rong; Wheeler, Tommy L.; Arthur, Terrance M.

    2014-01-01

    Specific concerns have been raised that third-generation cephalosporin-resistant (3GCr) Escherichia coli, trimethoprim-sulfamethoxazole-resistant (COTr) E. coli, 3GCr Salmonella enterica, and nalidixic acid-resistant (NALr) S. enterica may be present in cattle production environments, persist through beef processing, and contaminate final products. The prevalences and concentrations of these organisms were determined in feces and hides (at feedlot and processing plant), pre-evisceration carcasses, and final carcasses from three lots of fed cattle (n = 184). The prevalences and concentrations were further determined for strip loins from 103 of the carcasses. 3GCr Salmonella was detected on 7.6% of hides during processing and was not detected on the final carcasses or strip loins. NALr S. enterica was detected on only one hide. 3GCr E. coli and COTr E. coli were detected on 100.0% of hides during processing. Concentrations of 3GCr E. coli and COTr E. coli on hides were correlated with pre-evisceration carcass contamination. 3GCr E. coli and COTr E. coli were each detected on only 0.5% of final carcasses and were not detected on strip loins. Five hundred and 42 isolates were screened for extraintestinal pathogenic E. coli (ExPEC) virulence-associated markers. Only two COTr E. coli isolates from hides were ExPEC, indicating that fed cattle products are not a significant source of ExPEC causing human urinary tract infections. The very low prevalences of these organisms on final carcasses and their absence on strip loins demonstrate that current sanitary dressing procedures and processing interventions are effective against antimicrobial-resistant bacteria. PMID:25398858

  12. North-south component of galactic cosmic ray anisotropy at 1 AU

    NASA Astrophysics Data System (ADS)

    Ahluwalia, H. S.

    2015-12-01

    The galactic cosmic ray (GCR) solar diurnal anisotropy (SDA) may be represented by a vector (A; Ar, Aφ, Aθ) in a spherical polar coordinate system centered on the sun. We reported (elsewhere) the results of a detailed study of time variations of yearly radial (Ar) and east-west (Aφ) components recorded by the global network of the neutron monitors (NMs) with a long track record for 1963-2013, for four sunspot number (SSN) cycles (20-23) and the rising phase of cycle 24. A powerful new technique is used to compute and study time variations of the transverse component (Aθ) due to off-ecliptic GCR contributions, with the same NM data; GCR radial particle density gradient (Gr) drives all three components. The north-south anisotropy (Aθ) is computed from yearly NM data (Gϕ = 0), a flat heliospheric current sheet (HCS) model and the concept of GCR isotropic hard sphere scattering in the solar wind plasma. Relationships to SSN, rigidity and solar polarity intervals are studied. For a positive (p-) polarity the solar magnetic field in the northern hemisphere points outward and GCRs drift from polar regions toward equatorial plane and out along HCS, setting up a symmetric gradient (Gθs) pointing away from HCS (there is a local GCR density minimum on HCS); for n-polarity interval Gθs points towards HCS (there is a local GCR density maximum on HCS). Also, there exists a heliospheric asymmetric density gradient (Gθa) perpendicular to the ecliptic plane, it is the main contributor to Aθ for the period of our analysis. This is the most interesting and significant insight.

  13. Near-Earth Cosmic Ray Decreases Associated with Remote Coronal Mass Ejection

    NASA Astrophysics Data System (ADS)

    Thomas, Simon; Owens, Mathew; Lockwood, Mike; Barnard, Luke; Scott, Chris; Owen, Chris

    2015-04-01

    Galactic cosmic ray (GCR) flux is modulated by both particle drift patterns and solar wind structures on a range of time scales. Over solar cycles, GCR flux varies as a function of the total open solar magnetic flux and the latitudinal extent of the heliospheric current sheet. Over time-scales of hours, drops of a few percent in near-Earth GCR flux (Forbush decreases, FDs) are well known to be associated with the near-Earth passage of solar wind structures resulting from corotating interaction regions (CIRs) and transient coronal mass ejections (CMEs). We present four FDs seen at ground-based neutron monitors which cannot be immediately associated with significant structures in the local solar wind. Similarly, there are significant near-Earth structures which do not produce any corresponding GCR variation. Three of the FDs are shown to be during the STEREO era, enabling in-situ and remote observations from three well-separated heliospheric locations. Extremely large CMEs passed the STEREO-A spacecraft, which was behind the West limb of the Sun, approximately 2-3 days before each near-Earth FD. Solar wind simulations suggest that the CMEs combined with pre-existing CIRs, enhancing the pre-existing barriers to GCR propagation. These events are compared to the well-documented extreme event of July 2012 as a good comparison. Our observations provide strong evidence for the modulation of GCR flux by remote solar wind structures and a potential to detect these remote structures using neutron monitor data.

  14. Three dimensional non stationary mathematical model describing Forbush decreases of galactic cosmic ray intensity

    NASA Astrophysics Data System (ADS)

    Wawrzynczak, Anna; Alania, Michael V.

    2010-05-01

    Using experimental data we show that there exist a clear dependence of the exponent γ of the rigidity R spectrum δD(R)-D(R) ∞ R-γ of the Forbush decrease (Fd) of the galactic cosmic ray (GCR) intensity on the exponent ν of the Power Spectral Density (PSD) of the interplanetary magnetic field (IMF). To confirm this finding by theoretical study we propose a three dimensional (3D) non stationary model of the Fd of GCR intensity based on the Parker's transport equation taking into account diffusion, convection, drifts due to gradient and curvature of the IMF, and on the heliospheric neutral sheet with the energy changes in the diverged solar wind. This model implements the parameter describing the temporal changes of the IMF turbulence via the exponent ν of the PSD of the IMF. Owing to this innovation we confirm a relationship between the rigidity spectrum exponent γ and the exponent ν based on the numerical solutions of the 3D non stationary model of Fd. Also, we show that an increase of the size of the disturbed vicinity of the space causes the hardening of the rigidity spectrum of the Fd; namely, an increase of the size of the disturbed vicinity involves GCR particles with relatively larger larmour radius (in other equal conditions), so the GCR particles with the higher rigidities are modulated, which leads to the hardening of the rigidity spectrum (decreases). We find that for the higher rigidities of GCR particles a recovery time of the Fd is less than for the lower rigidities; a rate of the intensity reduction decreases with the increase of the diffusion coefficient and increasing GCR particle's rigidity. Theoretical calculations are compatible with the results obtained based on the neutron monitors and muon telescopes experimental data and confirm theoretically a unique dependence of the expected rigidity spectrum exponent γ of the Fd on the exponent ν of the PSD of the IMF turbulence.

  15. Assessment of galactic cosmic ray models

    NASA Astrophysics Data System (ADS)

    Mrigakshi, Alankrita Isha; Matthiä, Daniel; Berger, Thomas; Reitz, Günther; Wimmer-Schweingruber, Robert F.

    2012-08-01

    Among several factors involved in the development of a manned space mission concept, the astronauts' health is a major concern that needs to be considered carefully. Galactic cosmic rays (GCRs), which mainly consist of high-energetic nuclei ranging from hydrogen to iron and beyond, pose a major radiation health risk in long-term space missions. It is therefore required to assess the radiation exposure of astronauts in order to estimate their radiation risks. This can be done either by performing direct measurements or by making computer based simulations from which the dose can be derived. A necessary prerequisite for an accurate estimation of the exposure using simulations is a reliable description of the GCR spectra. The aim of this work is to compare GCR models and to test their applicability for the exposure assessment of astronauts. To achieve this, commonly used models capable of describing both light and heavy GCR particle spectra were evaluated by investigating the model spectra for various particles over several decades. The updated Badhwar-O'Neill model published in the year 2010, CREME2009 which uses the International Standard model for GCR, CREME96 and the Burger-Usoskin model were examined. Hydrogen, helium, oxygen and iron nuclei spectra calculated by the different models are compared with measurements from various high-altitude balloon and space-borne experiments. During certain epochs in the last decade, there are large discrepancies between the GCR energy spectra described by the models and the measurements. All the models exhibit weaknesses in describing the increased GCR flux that was observed in 2009-2010.

  16. Expression and Dexamethasone-induced Nuclear Translocation of Glucocorticoid and Mineralocorticoid Receptors in Guinea Pig Cochlear Cells

    PubMed Central

    Kil, Sung-Hee; Kalinec, Federico

    2013-01-01

    Glucocorticoids (GC) are powerful anti-inflammatory agents frequently used to protect the auditory organ against damage associated with a variety of conditions, including noise exposure and ototoxic drugs as well as bacterial and viral infections. In addition to glucocorticoid receptors (GC-R), natural and synthetic GC are known to bind mineralocorticoid receptors (MC-R) with great affinity. We used light and laser scanning confocal microscopy to investigate the expression of GC-R and MC-R in different cell populations of the guinea pig cochlea, and their translocation to different cell compartments after treatment with the synthetic GC dexamethasone. We found expression of both types of receptors in the cytoplasm and nucleus of sensory inner and outer hair cells as well as pillar, Hensen and Deiters cells in the organ of Corti, inner and outer sulcus cells, spiral ganglion neurons and several types of spiral ligament and spiral limbus cells; stria vascularis cells expressed mostly MC-R whereas fibrocytes type IV were positive for GC-R only. GC-R and MC-R were also localized at or near the plasma membrane of pillar cells and outer hair cells, whereas GC-R were found at or near the plasma membrane of Hensen cells only. We investigated the relative levels of receptor expression in the cytoplasm and the nucleus of Hensen cells treated with dexamethasone, and found they varied in a way suggestive of dose-induced translocation. These results suggest that the oto-protective effects of GC could be associated with the concerted activation of genomic and non-genomic, GC-R and MC-R mediated signaling pathways in different regions of the cochlea. PMID:23403298

  17. Assessment of Galactic Cosmic Ray Models and Implications on the Estimation of Radiation Exposure in Space

    NASA Astrophysics Data System (ADS)

    Mrigakshi, A. I.; Matthiä, D.; Berger, T.; Reitz, G.; Wimmer-Schweingruber, R. F.

    2012-12-01

    Astronauts are subjected to elevated levels of high-energy ionizing radiation in space which poses a substantial risk to their health. Therefore, the assessment of the radiation exposure for long duration manned spaceflight is essential. This is done by measuring dose using various detector techniques and by performing numerical simulations utilizing radiation transport codes which allow to predict radiation exposure for future missions and for conditions where measurements are not feasible or available. A necessary prerequisite for an accurate estimation of the exposure using the latter approach is a reliable description of the radiation spectra. Accordingly, in order to estimate the exposure from the Galactic Cosmic Rays (GCRs), which are one of the major sources of radiation exposure in space, GCR models are required. This work presents an evaluation of GCR models for dosimetry purposes and the effect of applying these models on the estimation of GCR exposure in space outside and inside the Earth's magnetosphere. To achieve this, widely used GCR models - Badhwar-O'Neill2010, Burger-Usoskin, CREME2009 and CREME96, were evaluated by comparing model spectra for light and heavy nuclei with measurements from various high-altitude balloon and space missions over several decades. Additionally a new model, based on the GCR-ISO model, developed at the German Aerospace Centre (DLR) was also investigated. The differences arising in the radiation exposure by applying these models are quantified in terms of absorbed dose and dose equivalent rates that were estimated numerically using the GEANT4 Monte-Carlo framework. During certain epochs in the last decade, there are large discrepancies between the model and the measured spectra. All models exhibit weaknesses in describing the increased GCR flux that was observed in 2009-2010. The differences in the spectra, described by the models, result in considerable differences in the estimated dose quantities.

  18. An Improved Analytic Model for Microdosimeter Response

    NASA Technical Reports Server (NTRS)

    Shinn, Judy L.; Wilson, John W.; Xapsos, Michael A.

    2001-01-01

    An analytic model used to predict energy deposition fluctuations in a microvolume by ions through direct events is improved to include indirect delta ray events. The new model can now account for the increase in flux at low lineal energy when the ions are of very high energy. Good agreement is obtained between the calculated results and available data for laboratory ion beams. Comparison of GCR (galactic cosmic ray) flux between Shuttle TEPC (tissue equivalent proportional counter) flight data and current calculations draws a different assessment of developmental work required for the GCR transport code (HZETRN) than previously concluded.

  19. Badhwar-O'Neill 2011 Galactic Cosmic Ray Model Update and Future Improvements

    NASA Technical Reports Server (NTRS)

    O'Neill, Pat M.; Kim, Myung-Hee Y.

    2014-01-01

    The Badhwar-O'Neill Galactic Cosmic Ray (GCR) Model based on actual GR measurements is used by deep space mission planners for the certification of micro-electronic systems and the analysis of radiation health risks to astronauts in space missions. The BO GCR Model provides GCR flux in deep space (outside the earth's magnetosphere) for any given time from 1645 to present. The energy spectrum from 50 MeV/n-20 GeV/n is provided for ions from hydrogen to uranium. This work describes the most recent version of the BO GCR model (BO'11). BO'11 determines the GCR flux at a given time applying an empirical time delay function to past sunspot activity. We describe the GCR measurement data used in the BO'11 update - modern data from BESS, PAMELA, CAPRICE, and ACE emphasized for than the older balloon data used for the previous BO model (BO'10). We look at the GCR flux for the last 24 solar minima and show how much greater the flux was for the cycle 24 minimum in 2010. The BO'11 Model uses the traditional, steady-state Fokker-Planck differential equation to account for particle transport in the heliosphere due to diffusion, convection, and adiabatic deceleration. It assumes a radially symmetrical diffusion coefficient derived from magnetic disturbances caused by sunspots carried onward by a constant solar wind. A more complex differential equation is now being tested to account for particle transport in the heliosphere in the next generation BO model. This new model is time-dependent (no longer a steady state model). In the new model, the dynamics and anti-symmetrical features of the actual heliosphere are accounted for so empirical time delay functions will no longer be required. The new model will be capable of simulating the more subtle features of modulation - such as the Sun's polarity and modulation dependence on the gradient and curvature drift. This improvement is expected to significantly improve the fidelity of the BO GCR model. Preliminary results of its performance will be presented.

  20. Issues in deep space radiation protection

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Shinn, J. L.; Tripathi, R. K.; Singleterry, R. C.; Clowdsley, M. S.; Thibeault, S. A.; Cheatwood, F. M.; Schimmerling, W.; Cucinotta, F. A.; Badhwar, G. D.; Noor, A. K.; Kim, M. Y.; Badavi, F. F.; Heinbockel, J. H.; Miller, J.; Zeitlin, C.; Heilbronn, L.

    2001-01-01

    The exposures in deep space are largely from the Galactic Cosmic Rays (GCR) for which there is as yet little biological experience. Mounting evidence indicates that conventional linear energy transfer (LET) defined protection quantities (quality factors) may not be appropriate for GCR ions. The available biological data indicates that aluminum alloy structures may generate inherently unhealthy internal spacecraft environments in the thickness range for space applications. Methods for optimization of spacecraft shielding and the associated role of materials selection are discussed. One material which may prove to be an important radiation protection material is hydrogenated carbon nanofibers. c 2001. Elsevier Science Ltd. All rights reserved.

  1. Accelerator experiments on the contribution of secondary particles to the production of cosmogenic nuclides in meteorites

    NASA Technical Reports Server (NTRS)

    Dragovitsch, P.; Englert, P.

    1985-01-01

    Through the interaction of galactic cosmic particle radiation (GCR) a wide variety of cosmogenic nuclides is produced in meteorites. They provide historical information about the cosmic radiation and the bombarded meteorites. An important way to understand the production mechanisms of cosmogenic nuclides in meteorites is to gather information about the depth and size dependence of the build-up of Galactic Rays Cosmic-secondary particles within meteorites of different sizes and chemical compositions. Simulation experiments with meteorite models offer an alternative to direct observation providing a data basis to describe the development and action of the secondary cascade induced by the GCR in meteorites.

  2. Managing Lunar and Mars Mission Radiation Risks. Part 1; Cancer Risks, Uncertainties, and Shielding Effectiveness

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Kim, Myung-Hee Y.; Ren, Lei

    2005-01-01

    This document addresses calculations of probability distribution functions (PDFs) representing uncertainties in projecting fatal cancer risk from galactic cosmic rays (GCR) and solar particle events (SPEs). PDFs are used to test the effectiveness of potential radiation shielding approaches. Monte-Carlo techniques are used to propagate uncertainties in risk coefficients determined from epidemiology data, dose and dose-rate reduction factors, quality factors, and physics models of radiation environments. Competing mortality risks and functional correlations in radiation quality factor uncertainties are treated in the calculations. The cancer risk uncertainty is about four-fold for lunar and Mars mission risk projections. For short-stay lunar missins (<180 d), SPEs present the most significant risk, but one effectively mitigated by shielding. For long-duration (>180 d) lunar or Mars missions, GCR risks may exceed radiation risk limits. While shielding materials are marginally effective in reducing GCR cancer risks because of the penetrating nature of GCR and secondary radiation produced in tissue by relativisitc particles, polyethylene or carbon composite shielding cannot be shown to significantly reduce risk compared to aluminum shielding. Therefore, improving our knowledge of space radiobiology to narrow uncertainties that lead to wide PDFs is the best approach to ensure radiation protection goals are met for space exploration.

  3. How Safe Is Safe Enough? Radiation Risk for a Human Mission to Mars

    PubMed Central

    Cucinotta, Francis A.; Kim, Myung-Hee Y.; Chappell, Lori J.; Huff, Janice L.

    2013-01-01

    Astronauts on a mission to Mars would be exposed for up to 3 years to galactic cosmic rays (GCR) — made up of high-energy protons and high charge (Z) and energy (E) (HZE) nuclei. GCR exposure rate increases about three times as spacecraft venture out of Earth orbit into deep space where protection of the Earth's magnetosphere and solid body are lost. NASA's radiation standard limits astronaut exposures to a 3% risk of exposure induced death (REID) at the upper 95% confidence interval (CI) of the risk estimate. Fatal cancer risk has been considered the dominant risk for GCR, however recent epidemiological analysis of radiation risks for circulatory diseases allow for predictions of REID for circulatory diseases to be included with cancer risk predictions for space missions. Using NASA's models of risks and uncertainties, we predicted that central estimates for radiation induced mortality and morbidity could exceed 5% and 10% with upper 95% CI near 10% and 20%, respectively for a Mars mission. Additional risks to the central nervous system (CNS) and qualitative differences in the biological effects of GCR compared to terrestrial radiation may significantly increase these estimates, and will require new knowledge to evaluate. PMID:24146746

  4. How Galactic Cosmic Ray models affect the estimation of radiation exposure in space

    NASA Astrophysics Data System (ADS)

    Mrigakshi, Alankrita Isha; Matthiä, Daniel; Berger, Thomas; Reitz, Günther; Wimmer-Schweingruber, Robert F.

    2013-03-01

    The radiation environment in space is a major concern for human spaceflight because of the adverse effects of high levels of radiation on astronauts' health. Therefore, it is essential to perform radiation risk assessments already during the concept studies of a manned mission. Galactic Cosmic Rays (GCR) have been identified to be one of the primary sources of radiation exposure in space.This work presents an evaluation of the radiation exposure caused by GCR between 1970 and 2011 in near-Earth interplanetary space and at the orbit of the International Space Station (ISS) by making numerical simulations with the Monte-Carlo framework GEANT4. Commonly used GCR models - CREME96, CREME2009 and Badhwar-O'Neill2010 are used to describe the GCR spectra and the differences arising from the application of these different models in terms of absorbed dose and dose equivalent rates are investigated. Additionally, the depth distribution of the dose quantities and the relative contribution of particles with different energies to the total exposure during solar maximum and minimum conditions are studied.The differences in the spectra, described by the models, result in considerable differences in the estimation of the radiation exposure.

  5. Galactic Cosmic Rays and Ion Induced Aerosol Production

    NASA Astrophysics Data System (ADS)

    Kazil, J.; Lovejoy, E. R.; Desorgher, L.

    2003-12-01

    The effect of ions on the production of sulfate aerosol in the Earth's atmosphere has been a topic of a number of modeling studies in the recent past. These studies were able to explain new particle formation in the middle and lower troposphere, observed in field campaigns under conditions where classical binary nucleation theory does not allow for a substantial particle production. However, recent observations of massive charged clusters in the upper troposphere indicate that ions may play an important role for aerosol formation in higher atmospheric regions as well. A major source of ions in the lower and middle atmosphere are galactic cosmic rays (GCR). The ion production due to GCR and the subsequent formation of sulfuric aerosol, together with its variations in altitude and solar cycle phase, were another topic of modeling studies. However, these studies relied mainly on theoretical approaches to ion-induced nucleation, and on sparse data of ion production in the atmosphere due to GCR. We present a study of aerosol formation based on laboratory thermochemistry data of negative sulfuric acid / water clusters and on modeled ion production rates due to GCR, covering different atmospheric regions. This approach allows for results which are subject to less quantitative uncertainties than previous work, and enables us to investigate and compare the aerosol production due to binary and ion-induced nucleation in various conditions.

  6. Comparison of CREME (cosmic-ray effects on microelectronics) model LET (linear energy transfer) spaceflight dosimetry data

    SciTech Connect

    Letaw, J.R.; Adams, J.H.

    1986-07-15

    The galactic cosmic radiation (GCR) component of space radiation is the dominant cause of single-event phenomena in microelectronic circuits when Earth's magnetic shielding is low. Spaceflights outside the magnetosphere and in high inclination orbits are examples of such circumstances. In high-inclination orbits, low-energy (high LET) particles are transmitted through the field only at extreme latitudes, but can dominate the orbit-averaged dose. GCR is an important part of the radiation dose to astronauts under the same conditions. As a test of the CREME environmental model and particle transport codes used to estimate single event upsets, we have compiled existing measurements of HZE doses were compiled where GCR is expected to be important: Apollo 16 and 17, Skylab, Apollo Soyuz Test Project, and Kosmos 782. The LET spectra, due to direct ionization from GCR, for each of these missions has been estimated. The resulting comparisons with data validate the CREME model predictions of high-LET galactic cosmic-ray fluxes to within a factor of two. Some systematic differences between the model and data are identified.

  7. How safe is safe enough? Radiation risk for a human mission to Mars.

    PubMed

    Cucinotta, Francis A; Kim, Myung-Hee Y; Chappell, Lori J; Huff, Janice L

    2013-01-01

    Astronauts on a mission to Mars would be exposed for up to 3 years to galactic cosmic rays (GCR)--made up of high-energy protons and high charge (Z) and energy (E) (HZE) nuclei. GCR exposure rate increases about three times as spacecraft venture out of Earth orbit into deep space where protection of the Earth's magnetosphere and solid body are lost. NASA's radiation standard limits astronaut exposures to a 3% risk of exposure induced death (REID) at the upper 95% confidence interval (CI) of the risk estimate. Fatal cancer risk has been considered the dominant risk for GCR, however recent epidemiological analysis of radiation risks for circulatory diseases allow for predictions of REID for circulatory diseases to be included with cancer risk predictions for space missions. Using NASA's models of risks and uncertainties, we predicted that central estimates for radiation induced mortality and morbidity could exceed 5% and 10% with upper 95% CI near 10% and 20%, respectively for a Mars mission. Additional risks to the central nervous system (CNS) and qualitative differences in the biological effects of GCR compared to terrestrial radiation may significantly increase these estimates, and will require new knowledge to evaluate. PMID:24146746

  8. 14 CFR 399.41 - Zones of limited suspension for international cargo rates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    .... (3) For all bulk rates (GCR's and SCR's) in the Western Hemisphere region (except Mexico and Canada.../Mexico transborder markets, 10 percent above the standard foreign rate level for the Western Hemisphere... any tariff if it finds that: (1) The suspension is in the public interest because of...

  9. Galactic Cosmic Ray Dose Rate at 1 A.U. During Solar Activity Cycle 24 Minimum

    NASA Astrophysics Data System (ADS)

    Golightly, M. J.; Schwadron, N. A.; Spence, H. E.; Wilson, J. K.; Case, A. W.; Townsend, L.; Kasper, J. C.; Blake, J. B.; Looper, M. D.; Mazur, J. E.

    2011-12-01

    Measurements made by the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument aboard the Lunar Reconnaissance Orbiter (LRO) have been used to create a time history of the absorbed dose rate resulting from galactic cosmic rays (GCR) exposure at a distance from the Sun of 1 astronomical unit (A.U.). These measurements, made during the period 2009-06-26 to 2010-12-31, include the deepest point of solar minimum activity (2009 Oct), maximum GCR dose rate (2010 Jan), and the onset of the first solar energetic particle (SEP) events of solar activity cycle 24 (2010 Jun). General features of the dose rate time history include: (a) an approximately 90-day lag between an increase in the coronal mass ejection (CME) rate/IMF field strength and the modulation of the daily GCR dose rate; a 21% decrease in the average daily GCR dose rate 15 months after solar activity minimum; and the detection of a cluster of 5 particle enhancements between 2010-06-12 and 2010-08-20 at the location of the LRO orbiter. Three additional enhancements measured between 2010-09-01 and 2010-09-23 do not appear to be linked with any observed solar activity, although two of the enhancements occurred during passage of coronal high-speed solar wind streams at the location of Earth.

  10. Rigidity spectrum of the long-period variations of the galactic cosmic ray intensity in different epochs of solar activity

    NASA Astrophysics Data System (ADS)

    Iskra, K.; Siluszyk, M.; Alania, M.

    2015-08-01

    We investigate character of correlations between the rigidity spectrum exponent γ of the 11-year variations of the Galactic Cosmic Ray (GCR) intensity and the exponent v of the Power Spectral Density (PSD) of the Interplanetary Magnetic Field (IMF) turbulence in period 1968-2012 using data of the IMF and carefully selected neutron monitors. We show that a clear inversely correlation between γ and v is observed when a resonance frequency range f1-f2 of the IMF turbulence (using for calculation of v), are determined taking into account changes of the solar wind velocity Vsw and strength B of the IMF versus solar activity. We assume that an essential contribution to the scattering of GCR particles in the heliosphere is setting up generally by the turbulence of By and Bz components of the IMF. Therefore, in this paper we use the exponents vy and vz of PSD of the By and Bz components of the IMF turbulence. Generally, both γ and v can be accepted as the essential proxies to study GCR propagation near earth orbit in heliosphere for the rigidity range of GCR particles to which neutron monitors and ground muon telescopes respond

  11. Impact of Consciousness-Raising Activities on Young English Language Learners' Grammar Performance

    ERIC Educational Resources Information Center

    Fatemipour, Hamidreza; Hemmati, Shiva

    2015-01-01

    Grammar Consciousness-Raising (GCR) is an approach to teaching of grammar which learners instead of being taught the given rules, experience language data. The data challenge them to rethink, restructure their existing mental grammar and construct an explicit rule to describe the grammatical feature which the data illustrate (Ellis, 2002). And…

  12. Mars surface radiation exposure for solar maximum conditions and 1989 solar proton events

    NASA Technical Reports Server (NTRS)

    Simonsen, Lisa C.; Nealy, John E.

    1992-01-01

    The Langley heavy-ion/nucleon transport code, HZETRN, and the high-energy nucleon transport code, BRYNTRN, are used to predict the propagation of galactic cosmic rays (GCR's) and solar flare protons through the carbon dioxide atmosphere of Mars. Particle fluences and the resulting doses are estimated on the surface of Mars for GCR's during solar maximum conditions and the Aug., Sep., and Oct. 1989 solar proton events. These results extend previously calculated surface estimates for GCR's at solar minimum conditions and the Feb. 1956, Nov. 1960, and Aug. 1972 solar proton events. Surface doses are estimated with both a low-density and a high-density carbon dioxide model of the atmosphere for altitudes of 0, 4, 8, and 12 km above the surface. A solar modulation function is incorporated to estimate the GCR dose variation between solar minimum and maximum conditions over the 11-year solar cycle. By using current Mars mission scenarios, doses to the skin, eye, and blood-forming organs are predicted for short- and long-duration stay times on the Martian surface throughout the solar cycle.

  13. Cosmic Ray 11-Year Modulation for Sunspot Cycle 24

    NASA Astrophysics Data System (ADS)

    Ahluwalia, H. S.; Ygbuhay, R. C.

    2015-02-01

    Galactic cosmic-ray (GCR) modulation at 1 AU for sunspot (SSN) Cycle 24 is studied using data from a global network of detectors and balloon measurements of low-energy ions at high latitudes in Russia. The observed modulation is modest compared with previous cycles. The tilt angle of the heliospheric current sheet reached a maximum value for Cycle 24 even though the peak of the interplanetary magnetic-field intensity at 1 AU has a much lower value (≈ 5 nT). The solar polar field in the northern hemisphere reversed in June 2012 and again in March 2014 while that in the southern hemisphere reversed in July 2013. The double field reversal in northern hemisphere after SSN maximum is not expected from dynamo theory. GCR modulation is at maximum phase in 2013. We have also studied the anomalous GCR recovery in 2009 using data from a low-energy proton channel on Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA). The rigidity dependence of the Cycle 24 modulation is computed using data from neutron monitors, directional muon telescopes at Nagoya, Japan, and detectors on balloons at high latitudes in Russia. It is a power law with an exponent -1.29, similar to previous solar cycles (-1.2±0.1); the nearly linear dependence of the modulation on the rigidity over a wide range poses a challenge to the quasi-linear theory (QLT) of GCR modulation.

  14. Predictors of Satisfaction in Geographically Close and Long-Distance Relationships

    ERIC Educational Resources Information Center

    Lee, Ji-yeon; Pistole, M. Carole

    2012-01-01

    In this study, the authors examined geographically close (GCRs) and long-distance (LDRs) romantic relationship satisfaction as explained by insecure attachment, self-disclosure, gossip, and idealization. After college student participants (N = 536) completed a Web survey, structural equation modeling (SEM) multigroup analysis revealed that the GCR

  15. GUIDELINES FOR DETERMINATION OF LABORATORY ACCEPTABILITY FOR ANALYSIS OF VOLATILE ORGANIC POLLUTANTS COLLECTED ON TENAX GC (TRADE NAME) ADSORBENT

    EPA Science Inventory

    A Technical Assistant Document (TAD) has been prepared which is intended to serve as a guide to those persons responsible for evaluating and/or selecting a laboratory to perform sampling and analysis of airborne, organic pollutants using Tenax GCR polymer and gas chromatography/m...

  16. The Projection of Space Radiation Environments with a Solar Cycle Statistical Model

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee; Cucinotta, Francis A.; Wilson, John W.

    2006-01-01

    A solar cycle statistical model has been developed to project sunspot numbers which represent the variations in the space radiation environment. The resultant projection of sunspot numbers in near future were coupled to space-related quantities of interest in radiation protection, such as the galactic cosmic radiation (GCR) deceleration potential (f) and the mean occurrence frequency of solar particle event (SPE). Future GCR fluxes have been derived from a predictive model, in which GCR temporal dependence represented by f was derived from GCR flux and ground-based Climax neutron monitor rate measurements over the last four decades. Results showed that the point dose equivalent inside a typical spacecraft in interplanetary radiation fields was influenced by solar modulation up to a factor of three. One important characteristic of sporadic SPEs is their mean frequency of occurrence, which is dependent on solar activity. Projections of future mean frequency of SPE occurrence were estimated from a power law function of sunspot number. Furthermore, the cumulative probabilities of SPE during short-period missions were defined with the continuous database of proton fluences of SPE. The analytic representation of energy spectra of SPE was constructed by the Weibull distribution for different event sizes. The representative exposure level at each event size was estimated for the guideline of protection systems for astronauts during future space exploration missions.

  17. Commitment Predictors: Long-Distance versus Geographically Close Relationships

    ERIC Educational Resources Information Center

    Pistole, M. Carole; Roberts, Amber; Mosko, Jonathan E.

    2010-01-01

    In this web-based study, the authors examined long-distance relationships (LDRs) and geographically close relationships (GCRs). Two hierarchical multiple regressions (N = 138) indicated that attachment predicted LDR and GCR commitment in Step 1. Final equations indicated that high satisfaction and investments predicted LDR commitment, whereas low…

  18. Force-field parameterization of the galactic cosmic ray spectrum: Validation for Forbush decreases

    NASA Astrophysics Data System (ADS)

    Usoskin, I. G.; Kovaltsov, G. A.; Adriani, O.; Barbarino, G. C.; Bazilevskaya, G. A.; Bellotti, R.; Boezio, M.; Bogomolov, E. A.; Bongi, M.; Bonvicini, V.; Bottai, S.; Bruno, A.; Cafagna, F.; Campana, D.; Carbone, R.; Carlson, P.; Casolino, M.; Castellini, G.; De Donato, C.; De Santis, C.; De Simone, N.; Di Felice, V.; Formato, V.; Galper, A. M.; Karelin, A. V.; Koldashov, S. V.; Koldobskiy, S.; Krutkov, S. Y.; Kvashnin, A. N.; Leonov, A.; Malakhov, V.; Marcelli, L.; Martucci, M.; Mayorov, A. G.; Menn, W.; Mergé, M.; Mikhailov, V. V.; Mocchiutti, E.; Monaco, A.; Mori, N.; Munini, R.; Osteria, G.; Palma, F.; Panico, B.; Papini, P.; Pearce, M.; Picozza, P.; Pizzolotto, C.; Ricci, M.; Ricciarini, S. B.; Rossetto, L.; Sarkar, R.; Scotti, V.; Simon, M.; Sparvoli, R.; Spillantini, P.; Stozhkov, Y. I.; Vacchi, A.; Vannuccini, E.; Vasilyev, G. I.; Voronov, S. A.; Yurkin, Y. T.; Zampa, G.; Zampa, N.; Zverev, V. G.

    2015-06-01

    A useful parametrization of the energy spectrum of galactic cosmic rays (GCR) near Earth is offered by the so-called force-field model which describes the shape of the entire spectrum with a single parameter, the modulation potential. While the usefulness of the force-field approximation has been confirmed for regular periods of solar modulation, it was not tested explicitly for disturbed periods, when GCR are locally modulated by strong interplanetary transients. Here we use direct measurements of protons and α -particles performed by the PAMELA space-borne instrument during December 2006, including a major Forbush decrease, in order to directly test the validity of the force-field parameterization. We conclude that (1) The force-field parametrization works very well in describing the energy spectra of protons and α -particles directly measured by PAMELA outside the Earths atmosphere; (2) The energy spectrum of GCR can be well parameterized by the force-field model also during a strong Forbush decrease; (3) The estimate of the GCR modulation parameter, obtained using data from the world-wide neutron monitor network, is in good agreement with the spectra directly measured by PAMELA during the studied interval. This result is obtained on the basis of a single event analysis, more events need to be analyzed.

  19. Sex differences in operant responding and survivability following exposure to space radiation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    On exploratory class missions, such as a mission to Mars, astronauts will be exposed to types and doses of radiation (galactic cosmic rays [GCR]) which are not experienced in low earth orbit where the space shuttle and International Space Station operate. Despite the fact that the crew on such a mi...

  20. Do supernovae of type 1 paly a role in cosmic-ray production?

    NASA Technical Reports Server (NTRS)

    Shapiro, M. M.

    1985-01-01

    A model of cosmic-ray origin is suggested which aims to account for some salient features of the composition. Relative to solar abundances, the Galactic cosmic rays (GCR) are deficient in hydrogen and helim (H and He) by an order of magnitude when the two compositions are normalized at iron. Our conjectural model implicates supernovae of Type I (SN-I) as sources of some of the GCR. SN-I occur approximately as often as SN-II, through their genesis is thought to be different. Recent studies of nucleosynthesis in SN-I based on accreting white dwarfs, find that the elements from Si to Fe are produced copiously. On the other hand, SN-I are virtually devoid of hydrogen, and upper limits deduced for He are low. If SN-I contribute significantly to the pool of GCR by injecting energetic particles into the interstellar medium (ISM), then this could explain why the resulting GCR is relatively deficient in H and He. A test of the model is proposed, and difficulties are discussed.

  1. A heavy ion spectrometer system for the measurement of projectile fragmentation of relativistic heavy ions

    SciTech Connect

    Engelage, J.; Crawford, H.J.; Greiner, L.; Kuo, C.

    1996-06-01

    The Heavy Ion Spectrometer System (HISS) at the LBL Bevalac provided a unique facility for measuring projectile fragmentation cross sections important in deconvolving the Galactic Cosmic Ray (GCR) source composition. The general characteristics of the apparatus specific to this application are described and the main features of the event reconstruction and analysis used in the TRANSPORT experiment are discussed.

  2. Space Radiation Transport Codes: A Comparative Study for Galactic Cosmic Rays Environment

    NASA Astrophysics Data System (ADS)

    Tripathi, Ram; Wilson, John W.; Townsend, Lawrence W.; Gabriel, Tony; Pinsky, Lawrence S.; Slaba, Tony

    For long duration and/or deep space human missions, protection from severe space radiation exposure is a challenging design constraint and may be a potential limiting factor. The space radiation environment consists of galactic cosmic rays (GCR), solar particle events (SPE), trapped radiation, and includes ions of all the known elements over a very broad energy range. These ions penetrate spacecraft materials producing nuclear fragments and secondary particles that damage biological tissues, microelectronic devices, and materials. In deep space missions, where the Earth's magnetic field does not provide protection from space radiation, the GCR environment is significantly enhanced due to the absence of geomagnetic cut-off and is a major component of radiation exposure. Accurate risk assessments critically depend on the accuracy of the input information as well as radiation transport codes used, and so systematic verification of codes is necessary. In this study, comparisons are made between the deterministic code HZETRN2006 and the Monte Carlo codes HETC-HEDS and FLUKA for an aluminum shield followed by a water target exposed to the 1977 solar minimum GCR spectrum. Interaction and transport of high charge ions present in GCR radiation environment provide a more stringent constraint in the comparison of the codes. Dose, dose equivalent and flux spectra are compared; details of the comparisons will be discussed, and conclusions will be drawn for future directions.

  3. Impact of galactic cosmic radiation and CO2 on Phanerozoic climate change

    NASA Astrophysics Data System (ADS)

    Wallmann, Klaus

    The flux of galactic cosmic radiation (GCR) reaching the solar system has been modulated periodically by the passage of the solar system through the spiral arms of our galaxy on long geological time scales (tens of millions of years) while solar irradiance increased continuously due to the aging of the sun. Therefore, the analysis of Phanerozoic time-series data allows for a discrimination between the potential effects of cosmic versus solar radiation on global climate change over the past 540 million years. The d18O record of marine carbonates features secular variations that are suggesting strong effects of GCR on Phanerozoic climate change. Against this background, a model is presented to evaluate the relative climate effects of atmospheric pCO2, GCR and solar irradiance over the Phanerozoic. The model is making use of the avail-able geological time series data (87Sr/86Sr, d13C, and d18O in marine carbonates and other geological archives) to constrain critical model parameter values and to evaluate the model output. The model confirms that the increase in solar radiation had no significant effect on the evolution of global mean surface temperatures over the model period. The climate evolution seems to be controlled by changes in GCR and pCO2. According to the model, the two major Phanerozoic glaciations during the late Carboniferous to early Permian and the late Cenozoic are the result of dense cloud coverage induced by strong GCR fluxes and carbon cycling pro-cesses causing a draw-down of atmospheric pCO2. The two moderately cool periods during the Ordovician -Silurian and late Jurassic -early Cretaceous are characterized by both high pCO2 and GCR levels such that greenhouse warming compensated for the cooling effect of GCR-enhanced cloudiness (Wallmann, 2004). References Wallmann, K., 2004. Impact of atmospheric CO2 and galactic cosmic radiation on Phanerozoic climate change and the marine d18O record. Geochemistry, Geophysics, Geosys-tems, 5(1): doi:10.1029/2003GC000683.

  4. Impact of atmospheric CO2 and galactic cosmic radiation on Phanerozoic climate change and the marine δ18O record

    NASA Astrophysics Data System (ADS)

    Wallmann, K.

    2004-06-01

    A new model is developed and applied to simulate the Phanerozoic evolution of seawater composition (dissolved Ca, Sr, dissolved inorganic carbon, alkalinity, pH, δ18O), marine carbonates (Sr/Ca, 87Sr/86Sr, δ13C, δ18O), atmospheric CO2 and surface temperature. The marine carbonate records (Sr/Ca, 87Sr/86Sr, δ13C) are used to reconstruct changes in volcanic/tectonic activity and organic carbon burial over the Phanerozoic. Seawater pH is calculated assuming saturation with respect to calcite and considering the changing concentration of dissolved Ca documented by brine inclusion data. The depth of calcite saturation is allowed to vary through time and the effects of changing temperature and pressure on the stability constants of the carbonate system are considered. Surface temperatures are calculated using the GEOCARB III approach considering also the changing flux of galactic cosmic radiation (GCR). It is assumed that GCR cools the surface of the Earth via enhanced cloud formation at low altitudes. The δ18O of marine carbonates is calculated considering the changing isotopic composition of seawater, the prevailing surface temperatures and seawater pH. Repeated model runs showed that the trends observed in the marine δ18O record can only be reproduced by the model if GCR is allowed to have a strong effect on surface temperature. The climate evolution predicted by the model is consistent with the geological record. Warm periods (Cambrian, Devonian, Triassic, Cretaceous) are characterized by low GCR levels. Cold periods during the late Carboniferous to early Permian and the late Cenozoic are marked by high GCR fluxes and low pCO2 values. The major glaciations occurring during these periods are the result of carbon cycling processes causing a draw-down of atmospheric CO2 and a coevally prevailing dense cloud cover at low-altitudes induced by strong GCR fluxes. The two moderately cool periods during the Ordovician - Silurian and Jurassic - early Cretaceous are characterized by both high pCO2 and GCR levels so that greenhouse warming compensated for the cooling effect of low-altitude clouds. The very high Jurassic δ18O values observed in the geological record are caused by low pH values in surface waters rather than cold surface conditions.

  5. First Results From the Martian Radiation Environment Experiment MARIE

    NASA Astrophysics Data System (ADS)

    Zeitlin, C.; Cleghorn, T. F.; Cucinotta, F. A.; Saganti, P.; Pinsky, L. S.; Andersen, V.; Lee, K. T.; Turner, R.; Atwell, W.

    2002-12-01

    The Martian Radiation Environment Experiment (MARIE), aboard the 2001 Mars Odyssey spacecraft, is returning the first detailed radiation data from Mars orbit. Characterization of the Martian radiation environment is a necessary precursor to eventual human exploration of Mars. MARIE, which consists primarily of an 8-element silicon detector telescope, is providing high-quality measurements of Solar Energetic Particles (SEP) from a unique vantage point, and is also able to measure a significant portion of the spectrum of Galactic Cosmic Rays (GCR). The GCR are composed of atomic nuclei with kinetic energies ranging from tens of MeV per nucleon to hundreds of GeV per nucleon and higher. Energy distributions typically peak in the region of several hundred MeV per nucleon. These highly charged and energetic particles can penetrate tens of centimeters of matter, including tissue and practical depths of spacecraft shielding. The combination of high energy and high ionization associated with heavy nuclei in the GCR make these particles much more effective in causing biological damage than a comparable dose of sparsely-ionizing radiation such as muons or X-rays. These particles therefore present a potentially serious long-term health risk to astronauts, particularly on missions outside the protection of the geomagnetosphere. At Mars, the GCR spectrum is expected to be substantially the same as seen at Earth, modulated slightly by variations in the solar magnetic field. The spectrum of SEP tends to be dominated by low-energy protons; though less exotic than heavy ions in the GCR, these particles, produced in Coronal Mass Ejections, pose the risk of acute radiation exposure, owing to the high fluxes that are often generated. SEP spectra for a given CME may be entirely different at Earth and Mars, for a variety of reasons. MARIE has been operational in Mars orbit since March 2002. Several solar events have been observed, in addition to GCR ions. We will present dosimetric results as well as preliminary particle spectra from SEP and GCR.

  6. Production and evolution of Li, Be, and B isotopes in the Galaxy

    NASA Astrophysics Data System (ADS)

    Prantzos, N.

    2012-06-01

    Context. We reassess the problem of the production and evolution of the light elements Li, Be and B and of their isotopes in the Milky Way in the light of new observational and theoretical developments. Aims: The main novelty is the introduction of a new scheme for the origin of Galactic cosmic rays (GCR), which for the first time enables a self-consistent calculation of their composition during galactic evolution. Methods: The scheme accounts for key features of the present-day GCR source composition, it is based on the wind yields of the Geneva models of rotating, mass-losing stars and it is fully coupled to a detailed galactic chemical evolution code. Results: We find that the adopted GCR source composition accounts naturally for the observations of primary Be and helps understanding why Be follows Fe more closely than O. We find that GCR produce ~70% of the solar 11B/10B isotopic ratio; the remaining 30% of 11B presumably result from ν-nucleosynthesis in massive star explosions. We find that GCR and primordial nucleosynthesis can produce at most ~30% of solar Li. At least half of the solar Li has to originate in low-mass stellar sources (red giants, asymptotic giant branch stars, or novae), but the required average yields of those sources are found to be much higher than obtained in current models of stellar nucleosynthesis. We also present radial profiles of LiBeB elemental and isotopic abundances in the Milky Way disc. We argue that the shape of those profiles - and the late evolution of LiBeB in general - reveals important features of the production of those light elements through primary and secondary processes.

  7. Atmospheric changes caused by galactic cosmic rays over the period 1960-2010

    NASA Astrophysics Data System (ADS)

    Jackman, C. H.; Marsh, D. R.; Kinnison, D. E.; Mertens, C. J.; Fleming, E. L.

    2015-12-01

    The Specified Dynamics version of the Whole Atmosphere Community Climate Model (SD-WACCM) and the Goddard Space Flight Center two-dimensional (GSFC 2-D) models are used to investigate the effect of galactic cosmic rays (GCRs) on the atmosphere over the 1960-2010 time period. The Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) computation of the GCR-caused ionization rates are used in these simulations. GCR-caused maximum NOx increases of 4-15 % are computed in the Southern polar troposphere with associated ozone increases of 1-2 %. NOx increases of ∼ 1-6 % are calculated for the lower stratosphere with associated ozone decreases of 0.2-1 %. The primary impact of GCRs on ozone was due to their production of NOx. The impact of GCRs varies with the atmospheric chlorine loading, sulfate aerosol loading, and solar cycle variation. Because of the interference between the NOx and ClOx ozone loss cycles (e.g., the ClO + NO2 + M → ClONO2 + M reaction) and the change in the importance of ClOx in the ozone budget, GCRs cause larger atmospheric impacts with less chlorine loading. GCRs also cause larger atmospheric impacts with less sulfate aerosol loading and for years closer to solar minimum. GCR-caused decreases of annual average global total ozone (AAGTO) were computed to be 0.2 % or less with GCR-caused tropospheric column ozone increases of 0.08 % or less and GCR-caused stratospheric column ozone decreases of 0.23 % or less. Although these computed ozone impacts are small, GCRs provide a natural influence on ozone and need to be quantified over long time periods.

  8. Physics of the Isotopic Dependence of Galactic Cosmic Ray Fluence Behind Shielding

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Saganti, Premkumar B.; Hu, Xiao-Dong; Kim, Myung-Hee Y.; Cleghorn, Timothy F.; Wilson, John W.; Tripathi, Ram K.; Zeitlin, Cary J.

    2003-01-01

    For over 25 years, NASA has supported the development of space radiation transport models for shielding applications. The NASA space radiation transport model now predicts dose and dose equivalent in Earth and Mars orbit to an accuracy of plus or minus 20%. However, because larger errors may occur in particle fluence predictions, there is interest in further assessments and improvements in NASA's space radiation transport model. In this paper, we consider the effects of the isotopic composition of the primary galactic cosmic rays (GCR) and the isotopic dependence of nuclear fragmentation cross-sections on the solution to transport models used for shielding studies. Satellite measurements are used to describe the isotopic composition of the GCR. Using NASA's quantum multiple-scattering theory of nuclear fragmentation (QMSFRG) and high-charge and energy (HZETRN) transport code, we study the effect of the isotopic dependence of the primary GCR composition and secondary nuclei on shielding calculations. The QMSFRG is shown to accurately describe the iso-spin dependence of nuclear fragmentation. The principal finding of this study is that large errors (plus or minus 100%) will occur in the mass-fluence spectra when comparing transport models that use a complete isotope grid (approximately 170 ions) to ones that use a reduced isotope grid, for example the 59 ion-grid used in the HZETRN code in the past, however less significant errors (less than 20%) occur in the elemental-fluence spectra. Because a complete isotope grid is readily handled on small computer workstations and is needed for several applications studying GCR propagation and scattering, it is recommended that they be used for future GCR studies.

  9. Radiation effects in space: The Clementine I mission

    SciTech Connect

    Guzik, T. G.; Clayton, E.; Wefel, J. P.

    1994-12-20

    The space radiation environment for the CLEMENTINE I mission was investigated using a new calculational model, CHIME, which includes the effects of galactic cosmic rays (GCR), anomalous component (AC) species and solar energetic particle (SEP) events and their variations as a function of time. Unlike most previous radiation environment models, CHIME is based upon physical theory and is {open_quotes}calibrated{close_quotes} with energetic particle measurements made over the last two decades. Thus, CHIME provides an advance in the accuracy of estimating the interplanetary radiation environment. Using this model we have calculated particle energy spectra, fluences and linear energy transfer (LET) spectra for all three major components of the CLEMENTINE I mission during 1994: (1) the spacecraft in lunar orbit, (2) the spacecraft during asteroid flyby, and (3) the interstate adapter USA in Earth orbit. Our investigations indicate that during 1994 the level of solar modulation, which dominates the variation in the GCR and AC flux as a function of time, will be decreasing toward solar minimum levels. Consequently the GCR and AC flux will be increasing during Y, the year and, potentially, will rise to levels seen during previous solar minimums. The estimated radiation environment also indicates that the AC will dominate the energetic particle spectra for energies below 30-50 MeV/nucleon, while the GCR have a peak flux at {approximately}300 MeV/nucleon and maintain a relatively high flux level up to >1000 MeV/nucleon. The AC significantly enhances the integrated flux for LET in the range 1 to 10 MeV/(mg/cm{sup 2}), but due to the steep energy spectra of the AC a relatively small amount of material ({approximately}50 mils of Al) can effectively shield against this component. The GCR are seen to be highly penetrating and require massive amounts of shielding before there is any appreciable decrease in the LET flux.

  10. Sunspot numbers, interplanetary magnetic field, and cosmic ray intensity at earth: Nexus for the twentieth century

    NASA Astrophysics Data System (ADS)

    Ahluwalia, H. S.

    2013-12-01

    The pivotal role played by the interplanetary magnetic field (B) in modulating galactic cosmic ray (GCR) intensity in the heliosphere is described. We show that the inverse correlation observed by Forbush (1958) between GCRs and sunspot numbers (SSNs) is reflected in high correlation between SSNs and B (cc = 0.94). The SSN data are available since 1700 and the derived B data since 1835. The paleo-cosmic ray data are available for several millennia in the form of 10Be radionuclide sequestered in polar ice. The data of the ion chambers (ICs) at the Cheltenham-Fredericksburg-Yakutsk (CFY) sites are combined to create a data string for 1937-1988. In turn, these data are used to extend the measurements of the low energy GCR ions (>0.1 GeV) at balloon altitudes at high latitudes in Russia to 1937. These data are then correlated to B and the fit parameters are used to extend the low energy ion data to 1900, creating the instrumental era GCR time series for the twentieth century. The derived GCR time series is compared to 10Be measured at two sites in Greenland, namely Dye 3 and NGRIP for 1900-2000 to check the internal consistency of datasets for the long-term trend. We find that the annual mean rate (%) for 1965 at NGRIP is an outlier. We replace it with the mean of 1964 and 1965 rates and construct a new re-normalized time series at NGIP, improving the agreement with the derived instrumental era GCR time series for the twentieth century as well. This should encourage its use by heliophysics community for varied applications.

  11. Voyager 1 and 2 Measurements of Galactic and Anomalous Cosmic Ray Intensities and Anisotropies in and Beyond the Heliosheath

    NASA Astrophysics Data System (ADS)

    Hill, M. E.; Decker, R. B.; Hamilton, D. C.; Krimigis, S. M.

    2014-12-01

    Voyager 1 (V1) exited the nominal heliosheath in August 2012, clearly demarcated by an extreme drop in heliospheric particle intensities known as the heliocliff. Whether it entered the interstellar medium proper or some other radically different region is still subject to debate, but observationally the galactic cosmic ray (GCR) intensities and anisotropies are still varying, apparently responding to heliospheric perturbations, and the region is certainly bearing little resemblance to the expected quiescent interstellar medium. Voyager 2 (V2) continues to push towards the outer boundary of the heliosheath, being in a region heavily influenced by the interstellar interaction, as evidenced by dramatically diverted plasma flows, measuring on average greater than 60 degrees from the radial. We have studied the anomalous cosmic ray (ACR) and GCR particle behavior using V1 and V2 Low Energy Charge Particle observations, beyond the termination shock, and report the largest measured ~3% second-order GCR anisotropy at V1 after the heliocliff crossing and the order-of-magnitude variations in ACR and GCR intensities at V2 (e.g., from 2007-2012). These V2 observations are dissonant with the steady intensity profiles seen at V1 during the same period in the heliosheath and are seemingly related to the proximity to the magnetically sectored heliosheath, which arises from the increasingly compressed heliospheric current sheet (HCS) folds. We extend our earlier post-heliocliff, V1 GCR anisotropy work to the entire the heliosheath (V1 and V2) and report on the relationship between particle intensities and newly released V2 magnetometer data, particularly in regard to the HCS location.

  12. Corotating solar wind structures and recurrent trains of enhanced diurnal variation in galactic cosmic rays

    SciTech Connect

    Yeeram, T.; Ruffolo, D.; Sáiz, A.; Kamyan, N.; Nutaro, T. E-mail: david.ruf@mahidol.ac.th E-mail: p_chang24@hotmail.com

    2014-04-01

    Data from the Princess Sirindhorn Neutron Monitor at Doi Inthanon, Thailand, with a vertical cutoff rigidity of 16.8 GV, were utilized to determine the diurnal anisotropy (DA) of Galactic cosmic rays (GCRs) near Earth during solar minimum conditions between 2007 November and 2010 November. We identified trains of enhanced DA over several days, which often recur after a solar rotation period (∼27 days). By investigating solar coronal holes as identified from synoptic maps and solar wind parameters, we found that the intensity and anisotropy of cosmic rays are associated with the high-speed streams (HSSs) in the solar wind, which are in turn related to the structure and evolution of coronal holes. An enhanced DA was observed after the onset of some, but not all, HSSs. During time periods of recurrent trains, the DA was often enhanced or suppressed according to the sign of the interplanetary magnetic field B, which suggests a contribution from a mechanism involving a southward gradient in the GCR density, n, and a gradient anisotropy along B × ∇n. In one non-recurrent and one recurrent sequence, an HSS from an equatorial coronal hole was merged with that from a trailing mid-latitude extension of a polar coronal hole, and the slanted HSS structure in space with suppressed GCR density can account for the southward GCR gradient. We conclude that the gradient anisotropy is a source of temporary changes in the GCR DA under solar minimum conditions, and that the latitudinal GCR gradient can sometimes be explained by the coronal hole morphology.

  13. May 2005 Halo CMEs and Galactic Cosmic Ray Flux Changes at Earth's Orbit

    NASA Astrophysics Data System (ADS)

    Ahluwalia, H. S.; Alania, M. V.; Wawrzynczak, A.; Ygbuhay, R. C.; Fikani, M. M.

    2014-05-01

    The pressure corrected hourly data from the global network of cosmic ray detectors, measurements of the interplanetary magnetic field (IMF) intensity ( B) at Earth's orbit and its components B x , B y , B z (in the geocentric solar ecliptic coordinates) are used to conduct a comprehensive study of the galactic cosmic ray (GCR) intensity fluctuations caused by the halo coronal mass ejection of 13 May 2005. Distinct differences exist in GCR timelines recorded by neutron monitors (NMs) and multidirectional muon telescopes (MTs), the latter respond to the high rigidity portion of the GCR differential rigidity spectrum. The Forbush decrease (FD) onset in MTs is delayed (˜5 h) with respect to the onset of a geomagnetic storm sudden commencement (SSC) and a large pre-increase is present in MT data before, during, and after the SSC onset, of unknown origin. The rigidity spectrum, for a range of GCR rigidities (≤200 GV), is a power law in rigidity (R) with a negative exponent ( γ=-1.05) at GCR minimum intensity, leading us to infer that the quasi-linear theory of modulation is inconsistent with observations at high rigidities (>1 GV); the results support the force field theory of modulation. At present, we do not have a comprehensive model for the FD explaining quantitatively all the observational features but we present a preliminary model listing physical processes that may contribute to a FD timeline. We explored the connections between different phases of the FD and the power spectra of IMF components but did not find a sustained relationship.

  14. Image transformation into device-dependent color printer description using 4th-order polynomial regression and object-oriented programming development of image processing modules

    NASA Astrophysics Data System (ADS)

    Mongeon, Michael C.

    1996-03-01

    This paper investigates the development of printer device profiles used in color document printing system environments when devices with intrinsically different gamut capabilities communicate with one another in a common (CIELAB) color space. While the main thrust of this activity focuses on the output printer, namely the Xerox 5760 printer, and its rendition of some device independent image description, characterizations are provided which investigate relative areas of photographic, monitor, and printer gamuts using a visual hue leaf comparison between devices. The printer is modeled using 4th-order polynomial regression which maps the device independent CIELAB image representation into device dependent printer CMYK. This technique results in 1.89 AEEavg over the training data set. Some key properties of the proposed calibration method are as follows: (1) Linearized CMYK tone reproduction curves with respect to AEEpaper to improve the distribution of calibration data in color space. (2) Application of GCR strategy and linearization to the calibration target prior to the regression on the measured CIELAB and original CMY values. Each strategy employs a K addition/No CMY removal method which maximizes printer gamut and relies on the regression to determine the appropriate CMY removal. The following GCR strategies are explored: CMY only (0% K addition), 50% K addition, 100% K addition, and non-linear K addition. A library of image processing algorithms is included, using LabView object oriented programming, which provides a modular approach for key color processing tasks. In the user interface, an image is selected with appropriate GCR strategy, and the program operates on the image. In general, the pictorial image quality is excellent for each GCR strategy with subtle differences between GCR approaches. Quantitative analysis of Q60 color matching performance is included.

  15. Large Galactic Cosmic Ray Anisotropies in the Heliosheath

    NASA Astrophysics Data System (ADS)

    Hill, M. E.; Decker, R. B.; Hamilton, D. C.; Brown, L. E.; Krimigis, S. M.; Roelof, E. C.

    2013-12-01

    The angular distribution of galactic cosmic ray (GCR) intensities had been observed to be nearly isotropic throughout the space age, with even the largest anisotropies falling well short of 1%. Voyager 1, after the initial GCR intensity enhancement in May 2012 and upon sustainably entering a region depleted of hot plasma on 25 August 2012 (Burlaga et al. 2013; Krimigis et al. 2013; Stone et al. 2013; Webber & McDonald 2013), has uncovered a new regime where large GCR anisotropies prevail. We recently reported on the largest GCR anisotropies observed (Krimigis et al., 2013; Hill et al., 2013), with the second order anisotropy of >200 MeV GCRs reaching ~3.5%. We developed a new technique to extract bi-directional intensities from a double-ended particle telescope that has asymmetric viewing geometry (i.e., the geometric factor for particle detection with one end is unequal to the geometric factor of the other end). Applying this technique we report here on the variation of GCR anisotropies at Voyager 1 and 2 in the depletion region, in the hot heliosheath, and upstream of the termination shock. Burlaga, L.F. et al, 2013, Science 341, 147-150, DOI: 10.1126/science.1235451. Hill, M.E. et al, 2013, presented at the 12th Ann. Inter. Astrophys. Conf., Myrtle Beach, SC, 15-19 April 2013. Krimigis, S.M. et al., 2013, Science 341, 144-147, DOI: 10.1126/science.1235721. Stone, E.C. et al., 2013, Science 341, 150-153, DOI: 10.1126/science.1236408. Webber & McDonald, 2013, Geophys. Res. Let. 40, 1665-1668, DOI: 10.1002/grl.50383.

  16. Simulation and Comparison of Martian Surface Ionization Radiation

    NASA Astrophysics Data System (ADS)

    Kim, M. Y.; Zeitlin, C. J.; Hassler, D.; Cucinotta, F.

    2013-12-01

    The spectrum of energetic particle radiation and corresponding doses at the surface of Mars is being characterized by the Radiation Assessment Detector (RAD), one of ten science instruments on the Mars Science Laboratory (MSL) Curiosity Rover. The time series of dose rate for the first 300 Sols after landing on Mars on August 6, 2012 is presented here. For the comparison to RAD measurements of dose rate, Martian surface ionization radiation is simulated by utilizing observed space quantities. The GCR primary radiation spectrum is calculated by using the Badhwar-O'Neill 2011 (BO11) galactic cosmic ray (GCR) model, which has been developed by utilizing all balloon and satellite GCR measurements since 1955 and the newer 1997-2012 Advanced Composition Explorer (ACE) measurements. In the BO11 model, solar modulation of the GCR primary radiation spectrum is described in terms of the international smoothed sunspot number and a time delay function. For the transport of the impingent GCR primary radiation through Mars atmosphere, a vertical distribution of atmospheric thickness at each elevation is calculated using the vertical profiles of atmospheric temperature and pressure made by Mars Global Surveyor measurements. At Gale Crater in the southern hemisphere, the seasonal variation of atmospheric thickness is accounted for the daily atmospheric pressure measurements of the MSL Rover Environmental Monitoring Station (REMS) by using low- and high-density models for cool- and warm-season, respectively. The spherically distributed atmospheric distance is traced along the slant path, and the resultant directional shielding by Martian atmosphere is coupled with Curiosity vehicle for dose estimates. We present predictions of dose rate and comparison to the RAD measurements. The simulation agrees to within +-20% with the RAD measurements showing clearly the variation of dose rate by heliospheric conditions, and presenting the sensitivity of dose rate by atmospheric pressure, which has been found from the RAD experiments and driven by thermal tides on Martian surface.

  17. Cosmogenic helium and neon in individual chondrules from Allende and Murchison: Implications for the precompaction exposure history of chondrules

    NASA Astrophysics Data System (ADS)

    Roth, A. S. G.; Baur, H.; Heber, V. S.; Reusser, E.; Wieler, R.

    2011-07-01

    We analyzed cosmogenic He and Ne in more than 60 individual chondrules separated from small chips from the carbonaceous chondrites Allende and Murchison. The goal of this work is to search for evidence of an exposure of chondrules to energetic particles—either solar or galactic—prior to final compaction of their host chondrites and prior to the exposure of the meteoroids to galactic cosmic rays (GCR) on their way to Earth. Production rates of GCR-produced He and Ne are calculated for each chondrule based on major element composition and a physical model of cosmogenic nuclide production in carbonaceous chondrites (Leya and Masarik 2009). All studied chondrules in Allende show nominal exposure ages identical to each other within uncertainties of a few hundred thousand years. Allende chondrules therefore show no signs of a precompaction exposure. The majority of the Murchison chondrules (the "normal" chondrules) also have nominal exposure ages identical within a few hundred thousand years. However, roughly 20% of the studied Murchison chondrules (the "pre-exposed" chondrules) contain considerably or even much higher concentrations of cosmogenic noble gases than the normal chondrules, equivalent to exposure ages to GCR at present-day fluxes in a 4π irradiation of up to about 30 Myr. The data do not allow to firmly conclude whether these excesses were acquired by an exposure of the pre-exposed chondrules to an early intense flux of solar energetic particles (solar cosmic rays) or rather by an exposure to GCR in the regolith of the Murchison parent asteroid. However, we prefer the latter explanation. Two major reasons are the GCR-like isotopic composition of the excess Ne and the distribution of solar flare tracks in Murchison samples.

  18. A field assessment of long-term laboratory sediment toxicity tests with the amphipod Hyalella azteca

    USGS Publications Warehouse

    Ingersoll, C.G.; Wang, N.; Hayward, J.M.R.; Jones, J.R.; Jones, S.B.; Ireland, D.S.

    2005-01-01

    Response of the amphipod Hyalella azteca exposed to contaminated sediments for 10 to 42 d in laboratory toxicity tests was compared to responses observed in controlled three-month invertebrate colonization exposures conducted in a pond. Sediments evaluated included a sediment spiked with dichlorodiphenyldichloroethane (DDD) or dilutions of a field sediment collected from the Grand Calumet River (GCR) in Indiana (USA) (contaminated with organic compounds and metals). Consistent effects were observed at the highest exposure concentrations (400 ??g DDD/goc [DDD concentrations normalized to grams of organic carbon (goc) in sedimentl or 4% GCR sediment) on survival, length, and reproduction of amphipods in the laboratory and on abundance of invertebrates colonizing sediments in the field. Effect concentrations for DDD observed for 10-d length and 42-d reproduction of amphipods (e.g., chronic value [ChV] of 66 ??g DDD/goc and 25% inhibition concentration [IC25] of 68 ??g DDD/goc for reproduction) were similar to the lowest effect concentrations for DDD measured on invertebrates colonizing sediment the field. Effect concentrations for GCR sediment on 28-d survival and length and 42-d reproduction and length of amphipods (i.e., ChVs of 0.20-0.66% GCR sediment) provided more conservative effect concentrations compared to 10-d survival or length of amphipods in the laboratory or the response of invertebrates colonizing sediment in the field (e.g., ChVs of 2.2% GCR sediment). Results of this study indicate that use of chronic laboratory toxicity tests with H. azteca and benthic colonization studies should be used to provide conservative estimates of impacts on benthic communities exposed to contaminated sediments. Bioaccumulation of DDD by oligochaetes colonizing the DDD-spiked sediment was similar to results of laboratory sediment tests previously conducted with the oligochaete Lumbriculus variegates, confirming that laboratory exposures can be used to estimate bioaccumulation by oligochaetes exposed in the field. ?? 2005 SETAC.

  19. Simulation and Comparison of Martian Surface Ionization Radiation

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; Zeitlin, Cary; Hassler, Donald M.; Cucinotta, Francis A.

    2013-01-01

    The spectrum of energetic particle radiation and corresponding doses at the surface of Mars is being characterized by the Radiation Assessment Detector (RAD), one of ten science instruments on the Mars Science Laboratory (MSL) Curiosity Rover. The time series of dose rate for the first 300 Sols after landing on Mars on August 6, 2012 is presented here. For the comparison to RAD measurements of dose rate, Martian surface ionization radiation is simulated by utilizing observed space quantities. The GCR primary radiation spectrum is calculated by using the Badhwar-O'Neill 2011 (BO11) galactic cosmic ray (GCR) model, which has been developed by utilizing all balloon and satellite GCR measurements since 1955 and the newer 1997-2012 Advanced Composition Explorer (ACE) measurements. In the BO11 model, solar modulation of the GCR primary radiation spectrum is described in terms of the international smoothed sunspot number and a time delay function. For the transport of the impingent GCR primary radiation through Mars atmosphere, a vertical distribution of atmospheric thickness at each elevation is calculated using the vertical profiles of atmospheric temperature and pressure made by Mars Global Surveyor measurements. At Gale Crater in the southern hemisphere, the seasonal variation of atmospheric thickness is accounted for the daily atmospheric pressure measurements of the MSL Rover Environmental Monitoring Station (REMS) by using low- and high-density models for cool- and warm-season, respectively. The spherically distributed atmospheric distance is traced along the slant path, and the resultant directional shielding by Martian atmosphere is coupled with Curiosity vehicle for dose estimates. We present predictions of dose rate and comparison to the RAD measurements. The simulation agrees to within +/- 20% with the RAD measurements showing clearly the variation of dose rate by heliospheric conditions, and presenting the sensitivity of dose rate by atmospheric pressure, which has been found from the RAD experiments and driven by thermal tides on Martian surface.

  20. The Average Quality Factors by TEPC for Charged Particles

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; Nikjoo, Hooshang; Cucinotta, Francis A.

    2004-01-01

    The quality factor used in radiation protection is defined as a function of LET, Q(sub ave)(LET). However, tissue equivalent proportional counters (TEPC) measure the average quality factors as a function of lineal energy (y), Q(sub ave)(Y). A model of the TEPC response for charged particles considers energy deposition as a function of impact parameter from the ion s path to the volume, and describes the escape of energy out of sensitive volume by delta-rays and the entry of delta rays from the high-density wall into the low-density gas-volume. A common goal for operational detectors is to measure the average radiation quality to within accuracy of 25%. Using our TEPC response model and the NASA space radiation transport model we show that this accuracy is obtained by a properly calibrated TEPC. However, when the individual contributions from trapped protons and galactic cosmic rays (GCR) are considered; the average quality factor obtained by TEPC is overestimated for trapped protons and underestimated for GCR by about 30%, i.e., a compensating error. Using TEPC's values for trapped protons for Q(sub ave)(y), we obtained average quality factors in the 2.07-2.32 range. However, Q(sub ave)(LET) ranges from 1.5-1.65 as spacecraft shielding depth increases. The average quality factors for trapped protons on STS-89 demonstrate that the model of the TEPC response is in good agreement with flight TEPC data for Q(sub ave)(y), and thus Q(sub ave)(LET) for trapped protons is overestimated by TEPC. Preliminary comparisons for the complete GCR spectra show that Q(sub ave)(LET) for GCR is approximately 3.2-4.1, while TEPC measures 2.9-3.4 for QQ(sub ave)(y), indicating that QQ(sub ave)(LET) for GCR is underestimated by TEPC.

  1. Assessing the experience in complex hepatopancreatobiliary surgery among graduating chief residents: Is the operative experience enough?

    PubMed Central

    Sachs, Teviah E.; Ejaz, Aslam; Weiss, Matthew; Spolverato, Gaya; Ahuja, Nita; Makary, Martin A.; Wolfgang, Christopher L.; Hirose, Kenzo; Pawlik, Timothy M.

    2015-01-01

    Introduction Resident operative autonomy and case volume is associated with posttraining confidence and practice plans. Accreditation Council for Graduate Medical Education requirements for graduating general surgery residents are four liver and three pancreas cases. We sought to evaluate trends in resident experience and autonomy for complex hepatopancreatobiliary (HPB) surgery over time. Methods We queried the Accreditation Council for Graduate Medical Education General Surgery Case Log (2003–2012) for all cases performed by graduating chief residents (GCR) relating to liver, pancreas, and the biliary tract (HPB); simple cholecystectomy was excluded. Mean (±SD), median [10th–90th percentiles] and maximum case volumes were compared from 2003 to 2012 using R2 for all trends. Results A total of 252,977 complex HPB cases (36% liver, 43% pancreas, 21% biliary) were performed by 10,288 GCR during the 10-year period examined (Mean = 24.6 per GCR). Of these, 57% were performed during the chief year, whereas 43% were performed as postgraduate year 1–4. Only 52% of liver cases were anatomic resections, whereas 71% of pancreas cases were major resections. Total number of cases increased from 22,516 (mean = 23.0) in 2003 to 27,191 (mean = 24.9) in 2012. During this same time period, the percentage of HPB cases that were performed during the chief year decreased by 7% (liver: 13%, pancreas 8%, biliary 4%). There was an increasing trend in the mean number of operations (mean ± SD) logged by GCR on the pancreas (9.1 ± 5.9 to 11.3 ± 4.3; R2 = .85) and liver (8.0 ± 5.9 to 9.4 ± 3.4; R2 = .91), whereas those for the biliary tract decreased (5.9 ± 2.5 to 3.8 ± 2.1; R2 = .96). Although the median number of cases [10th:90th percentile] increased slightly for both pancreas (7.0 [4.0:15] to 8.0 [4:20]) and liver (7.0 [4:13] to 8.0 [5:14]), the maximum number of cases preformed by any given GCR remained stable for pancreas (51 to 53; R2 = .18), but increased for liver (38 to 45; R2 = .32). The median number of HPB cases that GCR performed as teaching assistants (TAs) remained at zero during this time period. The 90th percentile of cases performed as TA was less than two for both pancreas and liver. Conclusion Roughly one-half of GCR have performed fewer than 10 cases in each of the liver, pancreas, or biliary categories at time of completion of residency. Although the mean number of complex liver and pancreatic operations performed by GCR increased slightly, the median number remained low, and the number of TA cases was virtually zero. Most GCR are unlikely to be prepared to perform complex HPB operations. PMID:24953270

  2. An Analytical Model for the Prediction of a Micro-Dosimeter Response Function

    NASA Technical Reports Server (NTRS)

    Badavi, Francis F.; Xapsos, Mike

    2008-01-01

    A rapid analytical procedure for the prediction of a micro-dosimeter response function in low Earth orbit (LEO), correlated with the Space Transportation System (STS, shuttle) Tissue Equivalent Proportional Counter (TEPC) measurements is presented. The analytical model takes into consideration the energy loss straggling and chord length distribution of the detector, and is capable of predicting energy deposition fluctuations in a cylindrical micro-volume of arbitrary aspect ratio (height/diameter) by incoming ions through both direct and indirect (ray) events. At any designated (ray traced) target point within the vehicle, the model accepts the differential flux spectrum of Galactic Cosmic Rays (GCR) and/or trapped protons at LEO as input. On a desktop PC, the response function of TEPC for each ion in the GCR/trapped field is computed at the average rate of 30 seconds/ion. The ionizing radiation environment at LEO is represented by O'Neill fs GCR model (2004), covering charged particles in the 1 less than or equal to Z less than or equal to 28. O'Neill's free space GCR model is coupled with the Langley Research Center (LaRC) angular dependent geomagnetic cutoff model to compute the transmission coefficient in LEO. The trapped proton environment is represented by a LaRC developed time dependent procedure which couples the AP8MIN/AP8MAX, Deep River Neutron Monitor (DRNM) and F10.7 solar radio frequency measurements. The albedo neutron environment is represented by the extrapolation of the Atmospheric Ionizing Radiation (AIR) measurements. The charged particle transport calculations correlated with STS 51 and 114 flights are accomplished by using the most recent version (2005) of the LaRC deterministic High charge (Z) and Energy TRaNsport (HZETRN) code. We present the correlations between the TEPC model predictions (response function) and TEPC measured differential/integral spectra in the lineal energy (y) domain for both GCR and trapped protons, with the conclusion that the model correctly accounts for the increase in flux at low y values where energetic ions are the primary contributor. We further discuss that, even with the incorporation of angular dependency in the cutoffs, comparison of the GCR differential/integral flux between STS 51 and 114 TEPC measured data and current calculations indicates that there still exists an underestimation by the simulations at low to mid range y values. This underestimation is partly related the exclusion of the secondary pion particle production from the current version of HZETRN.

  3. Validity of the Aluminum Equivalent Approximation in Space Radiation Shielding

    NASA Technical Reports Server (NTRS)

    Badavi, Francis F.; Adams, Daniel O.; Wilson, John W.

    2009-01-01

    The origin of the aluminum equivalent shield approximation in space radiation analysis can be traced back to its roots in the early years of the NASA space programs (Mercury, Gemini and Apollo) wherein the primary radiobiological concern was the intense sources of ionizing radiation causing short term effects which was thought to jeopardize the safety of the crew and hence the mission. Herein, it is shown that the aluminum equivalent shield approximation, although reasonably well suited for that time period and to the application for which it was developed, is of questionable usefulness to the radiobiological concerns of routine space operations of the 21 st century which will include long stays onboard the International Space Station (ISS) and perhaps the moon. This is especially true for a risk based protection system, as appears imminent for deep space exploration where the long-term effects of Galactic Cosmic Ray (GCR) exposure is of primary concern. The present analysis demonstrates that sufficiently large errors in the interior particle environment of a spacecraft result from the use of the aluminum equivalent approximation, and such approximations should be avoided in future astronaut risk estimates. In this study, the aluminum equivalent approximation is evaluated as a means for estimating the particle environment within a spacecraft structure induced by the GCR radiation field. For comparison, the two extremes of the GCR environment, the 1977 solar minimum and the 2001 solar maximum, are considered. These environments are coupled to the Langley Research Center (LaRC) deterministic ionized particle transport code High charge (Z) and Energy TRaNsport (HZETRN), which propagates the GCR spectra for elements with charges (Z) in the range I <= Z <= 28 (H -- Ni) and secondary neutrons through selected target materials. The coupling of the GCR extremes to HZETRN allows for the examination of the induced environment within the interior' of an idealized spacecraft as approximated by a spherical shell shield, and the effects of the aluminum equivalent approximation for a good polymeric shield material such as genetic polyethylene (PE). The shield thickness is represented by a 25 g/cm spherical shell. Although one could imagine the progression to greater thickness, the current range will be sufficient to evaluate the qualitative usefulness of the aluminum equivalent approximation. Upon establishing the inaccuracies of the aluminum equivalent approximation through numerical simulations of the GCR radiation field attenuation for PE and aluminum equivalent PE spherical shells, we Anther present results for a limited set of commercially available, hydrogen rich, multifunctional polymeric constituents to assess the effect of the aluminum equivalent approximation on their radiation attenuation response as compared to the generic PE.

  4. Time-dependent radiation hazard estimations during space flights

    NASA Astrophysics Data System (ADS)

    Dobynde, Mikhail; Shprits, Yuri; Drozdov, Alexander

    Cosmic particle radiation is a limiting factor for the out of magnetosphere crewed flights. The cosmic radiation uncrewed flights inside heliosphere and crewed flights inside of magnetosphere tend to become a routine procedure, whereas there have been only few shot time flights out of it (Apollo missions 1969-1972) with maximum duration less than a month. Long term crewed missions set much higher requirements to the radiation shielding, primarily because of long exposition term. Inside the helosphere there are two main sources of cosmic radiation: galactic cosmic rays (GCR) and coronal mass ejections (CME). GCR come from the outside of heliosphere forming a background of overall radiation that affects the spacecraft. The intensity of GCR is varied according to solar activity, increasing with solar activity decrease and backward, with the modulation time (time between nearest maxima) of 11 yeas. CME are shot term events, comparing to GCR modulation time, but are much more energetic. The probability of CME increases with the increase of solar activity. Time dependences of the intensity of these two components encourage looking for a time window of flight, when intensity and affection of CME and GCR would be minimized. Applying time dependent models of GCR spectra [1] and estimations of CME we show the time dependence of the radiation dose in a realistic human phantom [2] inside the shielding capsule. We pay attention to the shielding capsule design, looking for an optimal geometry parameters and materials. Different types of particles affect differently on the human providing more or less harm to the tissues. Incident particles provide a large amount of secondary particles while propagating through the shielding capsule. We make an attempt to find an optimal combination of shielding capsule parameters, namely material and thickness, that will effectively decrease the incident particle energy, at the same time minimizing flow of secondary induced particles and minimizing most harmful particle types flows. 1.Nymmik et. al., “Galactic cosmic ray flux simulation and prediction”, Adv. Space Res. 17:19-30, (1996); 2. Xu et. al., “VIP-Man: an image-based whole-body adult male model constructed from color photographs of the Visible Human Project for multi-particle Monte Carlo calculations” Health Phys. 78:476-86, (2000).

  5. On the validity of the aluminum equivalent approximation in space radiation shielding applications

    NASA Astrophysics Data System (ADS)

    Badavi, Francis F.; Adams, Daniel O.; Wilson, John W.

    2010-09-01

    The origin of the aluminum equivalent shield approximation in space radiation analysis can be traced back to its roots in the early years of the NASA space programs (Mercury, Gemini and Apollo) wherein the primary radiobiological concern was the intense sources of ionizing radiation causing short term effects which was thought to jeopardize the safety of the crew and hence the mission. Herein, it is shown that the aluminum equivalent shield approximation, although reasonably well suited for that time period and to the application for which it was developed, is of questionable usefulness to the radiobiological concerns of routine space operations of the 21st century which will include long stays onboard the International Space Station (ISS) and perhaps the moon. This is especially true for a risk based protection system, as appears imminent for deep space exploration where the long-term effects of Galactic Cosmic Ray (GCR) exposure is of primary concern. The present analysis demonstrates that sufficiently large errors in the interior particle environment of a spacecraft result from the use of the aluminum equivalent approximation, and such approximations should be avoided in future astronaut risk estimates. In this study, the aluminum equivalent approximation is evaluated as a means for estimating the particle environment within a spacecraft structure induced by the GCR radiation field. For comparison, the two extremes of the GCR environment, the 1977 solar minimum and the 2001 solar maximum, are considered. These environments are coupled to the Langley Research Center (LaRC) deterministic ionized particle transport code High charge ( Z) and Energy TRaNsport (HZETRN), which propagates the GCR spectra for elements with charges ( Z) in the range 1 ⩽ Z ⩽ 28 (H-Ni) and secondary neutrons through selected target materials. The coupling of the GCR extremes to HZETRN allows for the examination of the induced environment within the interior of an idealized spacecraft as approximated by a spherical shell shield, and the effects of the aluminum equivalent approximation for a good polymeric shield material such as generic polyethylene (PE). The shield thickness is represented by a 25 g/cm 2 spherical shell. Although, one could imagine the progression to greater thickness, the current range will be sufficient to evaluate the qualitative usefulness of the aluminum equivalent approximation. Upon establishing the inaccuracies of the aluminum equivalent approximation through numerical simulations of the GCR radiation field attenuation for PE and aluminum equivalent PE spherical shells, we further present results for a limited set of commercially available, hydrogen rich, multifunctional polymeric constituents to assess the effect of the aluminum equivalent approximation on their radiation attenuation response as compared to the generic PE.

  6. Radiation characteristics in the spherical tissue-equivalent phantom on the ISS during solar activity minimum according to the data from Liulin-5 experiment

    NASA Astrophysics Data System (ADS)

    Semkova, J.; Koleva, R.; Maltchev, St.; Bankov, N.; Benghin, V.; Chernykh, I.; Shurshakov, V.; Petrov, V.

    2013-07-01

    The Liulin-5 charged particle telescope observes the radiation characteristics in the spherical tissue-equivalent phantom of MATROSHKA-R international project on the International Space Station (ISS). Liulin-5 measures time resolved deposited energy spectra, linear energy transfer (LET) spectrum, flux and absorbed dose rates for electrons, protons and the biologically relevant heavy ion components of the cosmic radiation at three depths along the phantom's radius. We present some new results of Liulin-5 experiment obtained from June 2007 to March 2010. The average quality factor for different time intervals is between 2.7 and 4.4. Due to the heavy ions in LET spectrum of the galactic cosmic rays (GCR), the GCR quality factor is bigger than that of the trapped protons. The absorbed dose rates measured at depths in the phantom corresponding to the depths of blood forming organs in human body are 7.75-9.6 μGy/h and the dose equivalent rates are 24.6-36.7 μSv/h. Usually the trapped protons contribute about 60% of the total absorbed dose at 40 mm depth in the phantom and about 40% at 165 mm depth. The rest of the dose comes from GCR. Space Shuttle docking and the change of ISS attitude preformed for that purpose lead to a decrease in the total doses and to decreasing the trapped protons contributions. The doses from GCR are not affected neither by the depth of measurement not by Shuttle docking. At 165 mm depth in the phantom the largest fluxes along the ISS orbit are obtained from the trapped protons in the South Atlantic Anomaly (SAA) at L values 1.26-1.27, B∼0.198 Gs, geographical longitude ∼-51° to -55°, latitude ∼-28° to -29° and altitudes 361-363 km. Minimal values about 0.1 particles/cm2s were recorded at L∼1 from GCR, at L≥4 the GCR flux reaches 2.1 particles/cm2s.

  7. Full Mission Astronaut Radiation Exposure Assessments for Long Duration Lunar Surface Missions

    NASA Technical Reports Server (NTRS)

    Adamczyk, Anne M.; Clowdsley, Martha S.; Qualls, Garry D.; Blattnig, Steve B.; Lee, Kerry T.; Fry, Dan J.; Stoffle, Nicholas N.; Simonsen, Lisa C.; Slaba, Tony C.; Walker, Steven A.; Zapp, Edward N.

    2010-01-01

    Risk to astronauts due to ionizing radiation exposure is a primary concern for missions beyond Low Earth Orbit (LEO) and will drive mission architecture requirements, mission timelines, and operational practices. Both galactic cosmic ray (GCR) and solar particle event (SPE) environments pose a risk to astronauts for missions beyond LEO. The GCR environment, which is made up of protons and heavier ions covering a broad energy spectrum, is ever present but varies in intensity with the solar cycle, while SPEs are sporadic events, consisting primarily of protons moving outward through the solar system from the sun. The GCR environment is more penetrating and is more difficult to shield than SPE environments, but lacks the intensity to induce acute effects. Large SPEs are rare, but they could result in a lethal dose, if adequate shielding is not provided. For short missions, radiation risk is dominated by the possibility of a large SPE. Longer missions also require planning for large SPEs; adequate shielding must be provided and operational constraints must allow astronauts to move quickly to shielded locations. The dominant risk for longer missions, however, is GCR exposure, which accumulates over time and can lead to late effects such as cancer. SPE exposure, even low level SPE exposure received in heavily shielded locations, will increase this risk. In addition to GCR and SPE environments, the lunar neutron albedo resulting mainly from the interaction of GCRs with regolith will also contribute to astronaut risk. Full mission exposure assessments were performed for proposed long duration lunar surface mission scenarios. In order to accomplish these assessments, radiation shielding models were developed for a proposed lunar habitat and rover. End-to-End mission exposure assessments were performed by first calculating exposure rates for locations in the habitat, rover, and during extra-vehicular activities (EVA). Subsequently, total mission exposures were evaluated for proposed timelines. A number of computational tools and mathematical models, which have been incorporated into NASA's On-Line Tool for the Assessment of Radiation In Space (OLTARIS), were used for this study. These tools include GCR and SPE environment models, human body models, and the HZETRN space radiation transport code, which is used to calculate the transport of the charged particles and neutrons through shielding materials and human tissue. Mission exposure results, assessed in terms of effective dose, are presented for proposed timelines and recommendations are made for improved astronaut shielding and safer operational practice.

  8. Integration of the QMSFRG Database into the HZETRN Code

    NASA Technical Reports Server (NTRS)

    Cucinotta, F. A.; Shavers, M. R.; Tripathi, R. K.; Wilson, J. W.

    2001-01-01

    Accurate nuclear interaction data bases are needed for describing the transport of space radiation in matter including space craft structures, atmospheres, and tissues. Transport models support the identification and development of new material concepts for human and electronic part protection. Quantum effects are manifested in nuclear reactions in several ways including interference effects between terms in the multiple scattering series, the many-body nuclear wave functions (for e.g. the roles of shell structure and Fermi momentum) and nuclear clustering. The quantum multiple scattering fragmentation model (QMSFRG) is a comprehensive model for generating nuclear interaction databases for galactic cosmic ray (GCR) transport. Other nuclear databases including the NUCFRG model and Monte-Carlo simulation codes such as FLUKA, LAHET, HETC, and GEANT ignore quantum effects. These codes fail to describe many important features of nuclear reactions and are thus inaccurate for the evaluation of materials for radiation protection. Previously we have shown that quantum effects are manifested through constructive interference in forward production spectra, the effects of Fermi momentum on production spectra, cluster nuclei knockout, and the nuclear response function. Quantum effects are especially important for heavy ions with mass numbers less than 20 that dominate radiation transport in human tissues and for the materials that are expected to be superior in space radiation protection. We describe the integration of the QMSFRG model into the HZETRN transport code. Integration milestones include proper treatment of odd-even charge-mass effects in nuclear fragmentation and the momentum distribution of nucleon production from GCR primary heavy ions. We have also modified the two-body amplitudes in the model to include nuclear medium effects. In order to include a comprehensive description of the GCR isotopic composition in materials, we have described the isotopic composition of the GCR by extending the 59-isotope version of HZETRN to an 120-isotope version. The isotopic composition of most primary GCR elements (including H, He, C, N, O, Ne, Mg, Si, Ar, Ca, Cr, and Fe) are included in the extended model. We discuss results for the high-energy neutron composition inside materials, and the charge and mass distribution for benchmark GCR problems.

  9. Early Energetic Particle Irradiation of the HED Parent Body Regolith

    NASA Technical Reports Server (NTRS)

    Bogard, D. D.; Garrison, D. H.; Rao, M. N.

    1996-01-01

    Previous studies have shown that many individual grains within the dark phase of the Kapoeta howardite were irradiated with energetic particles while residing on the surface of the early HED regolith. Particle tracks in these grains vary in density by more than an order of magnitude and undoubtedly were formed by energetic heavy (Fe) ions associated with early solar flares. Early Irradiation of HED Regolith: Concentrations of excess Ne alone are not sufficient to decide between competing galactic and solar irradiation models. However, from recent studies of depth samples of oriented lunar rocks, we have shown that the cosmogenic 21-Ne/22-Ne ratio produced in feldspar differs substantially between Galactic Cosmic Radiation (GCR) and solar protons, and that this difference is exactly that predicted from cross-section data. Using Ne literature data and new isotopic data we obtained on acid-etched, separated feldspar from both the light and dark phases of Kapoeta, we derive 21-Ne/22-Ne = 0.80 for the recent GCR irradiation and 21-Ne/22-Ne = 0.68 for the early regolith irradiation. This derived ratio indicates that the early Ne production in the regolith occurred by both galactic and solar protons. If we adopt a likely one-component regolith model in which all grains were exposed to galactic protons but individual grains had variable exposure to solar protons, we estimate that this early GCR irradiation lasted for about 3-6 m.y. More complex two-component regolith models involving separate solar and galactic irradiation would permit this GCR age to be longer. Higher-energy solar protons would permit the GCR to be longer. Higher-energy solar protons would permit the GCR age to be shorter. Further, cosmogenic 126(Xe) in Kapoeta dark is no more than a factor of about 2 higher than that observed in Kapoeta light. Because 126(Xe) can only be formed by galactic protons and not solar protons, these data support a short GCR irradiation for the HED regolith. This would also be the maximum time peRiod for the solar irradiation. Various asteroidal regolith models, based on Monte Carlo modeling of impact rates as a function of size and on irradiation features of meteorites, predict surface exposure times of about 0.1 to 10 m.y., and depend on such factors as gravity, rock mechanical properties, and micrometeoroid flux. Because the depth at which solar Fe tracks are produced (is much less than 1 micrometer) is much less than the depth at which Solar Cosmic Rays (SCR) Ne is produced (about 1 cm), for a reasonably well-stirred HED regolith the "surface exposure time" for SCR 21-Ne production should be significantly longer than that for solar tracks and some other surface irradiation features. Enhanced Solar Proton Irradiation: For bulk samples of Kapoeta dark feldspar and a one-component regolith model, the derived ratio of 21-Ne/22-Ne = 0.68 implies that the early production ratio of SCR 21-Ne to GCR 21-Ne was about 0.5-1.5. This ratio is independent of any assumptions about the fraction of dark grains that are irradiated or of the variability in the degree of solar irradiation among grains. The 21-Ne SCR/GCR ratio indirectly derived from bulk Kapoeta pyroxene is somewhat larger, as is the ratio derived for simple two-component regolith models. Individual feldspar grains that were extensively solar irradiated would require even larger 21-Ne SCR/GCR production ratios. In contrast, the theoretical SCR/GCR production ratio for lunar feldspar with 0 g/CM2 shield ing is is less than or equal to 2, and the lowest ratio observed in near-surface samples of lunar anorthosites is less than or equal to 1. Considering the greater solar distance of Vesta (compared to the Moon), the likelihood that SCR 21-Ne was acquired under some shielding where production rates are lower, and the likelihood that the exposure time to galactic protons exceeded the exposure time to solar protons because of their very different penetration depths, the 21-Ne SCR/GCR production ratio on the HED parent body was probably < 0.1. The relatively large difference between the derived 21-Ne SCR/GCR ratio in Kapoeta dark feldspar and the estimated production ratio strongly indicates that the early solar irradiation involved a flux -20-50x the recent solar flux. This enhanced proton flux was probably associated with an overall greater solar activity in the first approximately 10(exp 7) to 10(exp 8) years of solar history.

  10. Optimized shielding for space radiation protection.

    PubMed

    Wilson, J W; Cucinotta, F A; Kim, M H; Schimmerling, W

    2001-01-01

    Future deep space mission and International Space Station exposures will be dominated by the high-charge and -energy (HZE) ions of the Galactic Cosmic Rays (GCR). A few mammalian systems have been extensively tested over a broad range of ion types and energies. For example, C3H10T1/2 cells, V79 cells, and Harderian gland tumors have been described by various track-structure dependent response models. The attenuation of GCR induced biological effects depends strongly on the biological endpoint, response model used, and material composition. Optimization of space shielding is then driven by the nature of the response model and the transmission characteristics of the given material. PMID:11770540

  11. Radiation quality of cosmic ray nuclei studied with Geant4-based simulations

    NASA Astrophysics Data System (ADS)

    Burigo, Lucas N.; Pshenichnov, Igor A.; Mishustin, Igor N.; Bleicher, Marcus

    2014-04-01

    In future missions in deep space a space craft will be exposed to a non-negligible flux of high charge and energy (HZE) particles present in the galactic cosmic rays (GCR). One of the major concerns of manned missions is the impact on humans of complex radiation fields which result from the interactions of HZE particles with the spacecraft materials. The radiation quality of several ions representing GCR is investigated by calculating microdosimetry spectra. A Geant4-based Monte Carlo model for Heavy Ion Therapy (MCHIT) is used to simulate microdosimetry data for HZE particles in extended media where fragmentation reactions play a certain role. Our model is able to reproduce measured microdosimetry spectra for H, He, Li, C and Si in the energy range of 150-490 MeV/u. The effect of nuclear fragmentation on the relative biological effectiveness (RBE) of He, Li and C is estimated and found to be below 10%.

  12. Effects of Nuclear Cross Sections at Different Energies on the Radiation Hazard from Galactic Cosmic Rays

    NASA Technical Reports Server (NTRS)

    Lin, Z. W.; Adams, J. H., Jr.

    2006-01-01

    The radiation hazard for astronauts from galactic cosmic rays is a major obstacle in long duration human space explorations. Space radiation transport codes have been developed to calculate radiation environment on missions to the Moon, Mars or beyond. We have studied how uncertainties in fragmentation cross sections at different energies affect the accuracy of predictions from such radiation transport. We find that, in deep space, cross sections between 0.3 and 0.85 GeV/u usually have the largest effect on dose-equivalent behind shielding in solar minimum GCR environments, and cross sections between 0.85 and 1.2 GeV/u have the largest effect in solar maximum GCR environments. At the International Space Station, cross sections at higher energies have the largest effect due to the geomagnetic cutoff.

  13. Light ion components of the galactic cosmic rays: Nuclear interactions and transport theory

    NASA Technical Reports Server (NTRS)

    Cucinotta, F. A.; Townsend, L. W.; Wilson, J. W.; Shinn, J. L.; Badhwar, G. D.; Dubey, R. R.

    1996-01-01

    Light nuclei are present in the primary galactic cosmic rays (GCR) and are produced in thick targets due to projectile or target fragmentation from both nucleon and heavy induced reactions. In the primary GCR, He-4 is the most abundant nucleus after H-1. However, there are also a substantial fluxes of H-2 and He-3. In this paper we describe theoretical models based on quantum multiple scattering theory for the description of light ion nuclear interactions. The energy dependence of the light ion fragmentation cross section is considered with comparisons of inclusive yields and secondary momentum distributions to experiments described. We also analyze the importance of a fast component of lights ions from proton and neutron induced target fragementation. These theoretical models have been incorporated into the cosmic ray transport code HZETRN and will be used to analyze the role of shielding materials in modulating the production and the energy spectrum of light ions.

  14. Study - Radiation Shielding Effectiveness of the Prototyped High Temperature Superconductivity (HTS) 'Artificial' Magnetosphere for Deep Space Missions

    NASA Technical Reports Server (NTRS)

    Denkins, Pamela

    2010-01-01

    The high temperature superconductor (HTS) is being used to develop the magnets for the Variable Specific Impulse Magneto-plasma Rocket (VASIMR ) propulsion system and may provide lightweight magnetic radiation shielding to protect spacecraft crews from radiation caused by GCR and SPEs on missions to Mars. A study is being planned to assess the radiation shielding effectiveness of the artificial magnetosphere produced by the HTS magnet. VASIMR is an advanced technology propulsion engine which is being touted as enabling one way transit to Mars in 90 days or less. This is extremely important to NASA. This technology would enable a significant reduction in the number of days in transit to and from Mars and significantly reduce the astronauts exposure to a major threat - high energy particles from solar storms and GCR during long term deep space missions. This paper summarizes the plans for the study and the subsequent testing of the VASIMR technology onboard the ISS slated for 2013.

  15. 3-D models of the Forbush decrease and 27-day variation of galactic cosmic rays with three dimensional divergence-free interplanetary magnetic field

    NASA Astrophysics Data System (ADS)

    Alania, Michael; Modzelewska, Renata; Wawrzynczak-Szaban, Anna

    2012-07-01

    We develop the three dimensional (3-D) models of the Forbush decrease (Fd) and 27-day variation of the galactic cosmic ray (GCR) intensity with the variable solar wind velocity. In the models is implemented a structure of the three dimensional interplanetary magnetic field (IMF) obtained as a numerical solution of Maxwell's equations with the heliolongitudinal and heliolatitudinal dependencies of the radial component of the solar wind velocity that approximately corresponds to in situ measurements. Based on the Bernoulli principle we consider the possible circumstances leading to the formation of the latitudinal B _{θ} component of the IMF due to violence of the equilibrium between different layers of the variable solar wind streams. We compare 3-D modeling results of the Forbush decrease (Fd) and 27-day variation of the GCR intensity with the observed variation of cosmic ray intensity from world wide network of neutron monitors.

  16. Suppression of gross chromosomal rearrangements by a new alternative replication factor C complex

    SciTech Connect

    Banerjee, Soma; Sikdar, Nilabja; Myung, Kyungjae

    2007-10-26

    Defects in DNA replication fidelity lead to genomic instability. Gross chromosomal rearrangement (GCR), a type of genomic instability, is highly enhanced by various initial mutations affecting DNA replication. Frequent observations of GCRs in many cancers strongly argue the importance of maintaining high fidelity of DNA replication to suppress carcinogenesis. Recent genome wide screens in Saccharomyces cerevisiae identified a new GCR suppressor gene, ELG1, enhanced level of genome instability gene 1. Its physical interaction with proliferating cell nuclear antigen (PCNA) and complex formation with Rfc2-5p proteins suggest that Elg1 functions to load/unload PCNA onto DNA during a certain DNA metabolism. High level of DNA damage accumulation and enhanced phenotypes with mutations in genes involved in cell cycle checkpoints, homologous recombination (HR), or chromatin assembly in the elg1 strain suggest that Elg1p-Rfc2-5p functions in a fundamental DNA metabolism to suppress genomic instability.

  17. Large inverted repeats in the vicinity of a single double-strand break strongly affect repair in yeast diploids lacking Rad51

    PubMed Central

    Downing, Brandon; Morgan, Rachel; VanHulle, Kelly; Deem, Angela; Malkova, Anna

    2008-01-01

    DNA double-strand breaks (DSBs) are critical lesions that can lead to cell death or chromosomal rearrangements. Rad51 is necessary for most mitotic and meiotic DSB repair events, although a number of RAD51-independent pathways exist. Previously, we described DSB repair in rad51Δ yeast diploids that was stimulated by a DNA region termed “facilitator of break-induced replication” (FBI) located approximately 30 kb from the site of an HO-induced DSB. Here, we demonstrate that FBI is a large inverted DNA repeat that channels repair of DSBs into the singlestrand annealing-gross chromosomal rearrangements (SSA-GCR) pathway. Further, analysis of DSB repair in rad54Δ cells allowed us to propose that the SSA-GCR repair pathway is suppressed in the presence of Rad51p. Therefore, an additional role of Rad51 might be to protect eukaryotic genomes from instabilities by preventing chromosomal rearrangements. PMID:18755201

  18. Galactic Cosmic Rays in the Outer Heliosphere

    NASA Technical Reports Server (NTRS)

    Florinski, V.; Washimi, H.; Pogorelov, N. V.; Adams, J. H.

    2010-01-01

    We report a next generation model of galactic cosmic ray (GCR) transport in the three dimensional heliosphere. Our model is based on an accurate three-dimensional representation of the heliospheric interface. This representation is obtained by taking into account the interaction between partially ionized, magnetized plasma flows of the solar wind and the local interstellar medium. Our model reveals that after entering the heliosphere GCRs are stored in the heliosheath for several years. The preferred GCR entry locations are near the nose of the heliopause and at high latitudes. Low-energy (hundreds of MeV) galactic ions observed in the heliosheath have spent, on average, a longer time in the solar wind than those observed in the inner heliosphere, which would explain their cooled-off spectra at these energies. We also discuss radial gradients in the heliosheath and the implications for future Voyager observations

  19. Badhwar - O'Neill 2014 Galactic Cosmic Ray Flux Model Description

    NASA Technical Reports Server (NTRS)

    O'Neill, P. M.; Golge, S.; Slaba, T. C.

    2014-01-01

    The Badhwar-O'Neill (BON) Galactic Cosmic Ray (GCR) model is based on GCR measurements from particle detectors. The model has mainly been used by NASA to certify microelectronic systems and the analysis of radiation health risks to astronauts in space missions. The BON14 model numerically solves the Fokker-Planck differential equation to account for particle transport in the heliosphere due to diffusion, convection, and adiabatic deceleration under the assumption of a spherically symmetric heliosphere. The model also incorporates an empirical time delay function to account for the lag of the solar activity to reach the boundary of the heliosphere. This technical paper describes the most recent improvements in parameter fits to the BON model (BON14). Using a comprehensive measurement database, it is shown that BON14 is significantly improved over the previous version, BON11.

  20. Radiation Physics for Space and High Altitude Air Travel

    NASA Technical Reports Server (NTRS)

    Cucinotta, F. A.; Wilson, J. W.; Goldhagen, P.; Saganti, P.; Shavers, M. R.; McKay, Gordon A. (Technical Monitor)

    2000-01-01

    Galactic cosmic rays (GCR) are of extra-solar origin consisting of high-energy hydrogen, helium, and heavy ions. The GCR are modified by physical processes as they traverse through the solar system, spacecraft shielding, atmospheres, and tissues producing copious amounts of secondary radiation including fragmentation products, neutrons, mesons, and muons. We discuss physical models and measurements relevant for estimating biological risks in space and high-altitude air travel. Ambient and internal spacecraft computational models for the International Space Station and a Mars mission are discussed. Risk assessment is traditionally based on linear addition of components. We discuss alternative models that include stochastic treatments of columnar damage by heavy ion tracks and multi-cellular damage following nuclear fragmentation in tissue.

  1. A space radiation shielding model of the Martian radiation environment experiment (MARIE)

    NASA Technical Reports Server (NTRS)

    Atwell, W.; Saganti, P.; Cucinotta, F. A.; Zeitlin, C. J.

    2004-01-01

    The 2001 Mars Odyssey spacecraft was launched towards Mars on April 7, 2001. Onboard the spacecraft is the Martian radiation environment experiment (MARIE), which is designed to measure the background radiation environment due to galactic cosmic rays (GCR) and solar protons in the 20-500 MeV/n energy range. We present an approach for developing a space radiation-shielding model of the spacecraft that includes the MARIE instrument in the current mapping phase orientation. A discussion is presented describing the development and methodology used to construct the shielding model. For a given GCR model environment, using the current MARIE shielding model and the high-energy particle transport codes, dose rate values are compared with MARIE measurements during the early mapping phase in Mars orbit. The results show good agreement between the model calculations and the MARIE measurements as presented for the March 2002 dataset. c2003 COSPAR. Published by Elsevier Ltd. All rights reserved.

  2. Numerical Study of the Generation of Linear Energy Transfer Spectra for Space Radiation Applications

    NASA Technical Reports Server (NTRS)

    Badavi, Francis F.; Wilson, John W.; Hunter, Abigail

    2005-01-01

    In analyzing charged particle spectra in space due to galactic cosmic rays (GCR) and solar particle events (SPE), the conversion of particle energy spectra into linear energy transfer (LET) distributions is a convenient guide in assessing biologically significant components of these spectra. The mapping of LET to energy is triple valued and can be defined only on open energy subintervals where the derivative of LET with respect to energy is not zero. Presented here is a well-defined numerical procedure which allows for the generation of LET spectra on the open energy subintervals that are integrable in spite of their singular nature. The efficiency and accuracy of the numerical procedures is demonstrated by providing examples of computed differential and integral LET spectra and their equilibrium components for historically large SPEs and 1977 solar minimum GCR environments. Due to the biological significance of tissue, all simulations are done with tissue as the target material.

  3. Cosmic-ray record in solar system matter

    NASA Technical Reports Server (NTRS)

    Reedy, R. C.; Arnold, J. R.; Lal, D.

    1983-01-01

    The interaction of galactic cosmic rays (GCR) and solar cosmic rays (SCR) with bodies in the solar system is discussed, and what the record of that interaction reveals about the history of the solar system is considered. The influence of the energy, charge, and mass of the particles on the interaction is addressed, showing long-term average fluxes of solar protons, predicted production rates for heavy-nuclei tracks and various radionuclides as a function of depth in lunar rock, and integral fluxes of protons emitted by solar flares. The variation of the earth's magnetic field, the gardening of the lunar surface, and the source of meteorites and cosmic dust are studied using the cosmic ray record. The time variation of GCR, SCR, and VH and VVH nuclei is discussed for both the short and the long term.

  4. Low-energy Galactic centre gamma-rays from low-mass X-ray binaries

    NASA Technical Reports Server (NTRS)

    Kluzniak, W.; Ruderman, M.; Shaham, J.; Tavani, M.

    1988-01-01

    Nonthermal processes in low-mass X-ray binaries concentrated in the Galactic bulge are proposed as the direct source of the three continuum components of the emission from the Galactic center region (GCR) and also, possibly, as the indirect source of the 511-keV electron-positron annihilation line. It is suggested that the softer power-law component of the GCR continuum arises from synchrotron emission of relativistic electrons in the strongly nonuniform magnetic field of the neutron star and, more tentatively, that the MeV bump is the result of interaction of harder gamma rays with power-law photons. The hardest power law may be due to Compton scattering of relativistic electrons or photons.

  5. Radiological health risks

    NASA Technical Reports Server (NTRS)

    Nachtwey, D. Stuart

    1989-01-01

    The crew of a manned Mars mission will be unavoidably exposed to galactic cosmic ray (GCR) flux. The Mars mission crew shielded by 2 g/sq cm Al could receive about 0.7 Sv in a 460-day mission at solar minimum. However, three-fourths of this dose-equivalent in free space is contributed by high LET heavy ions (Z 3 or greater) and target fragments with average Q of 10.3 and 20, respectively. Such high quality factors for these particles may be inappropriate. Moreover, in a 460-day mission, less than half of the nuclei in the body of an astronaut will have been traversed by a single heavy particle. The entire concept of absorbed dose/quality factors/dose-equivalents as applied to GCR must be reconsidered.

  6. Expansion of Interstitial Telomeric Sequences in Yeast.

    PubMed

    Aksenova, Anna Y; Han, Gil; Shishkin, Alexander A; Volkov, Kirill V; Mirkin, Sergei M

    2015-11-24

    Telomeric repeats located within chromosomes are called interstitial telomeric sequences (ITSs). They are polymorphic in length and are likely hotspots for initiation of chromosomal rearrangements that have been linked to human disease. Using our S. cerevisiae system to study repeat-mediated genome instability, we have previously shown that yeast telomeric (Ytel) repeats induce various gross chromosomal rearrangements (GCR) when their G-rich strands serve as the lagging strand template for replication (G orientation). Here, we show that interstitial Ytel repeats in the opposite C orientation prefer to expand rather than cause GCR. A tract of eight Ytel repeats expands at a rate of 4 10(-4) per replication, ranking them among the most expansion-prone DNA microsatellites. A candidate-based genetic analysis implicates both post-replication repair and homologous recombination pathways in the expansion process. We propose a model for Ytel repeat expansions and discuss its applications for genome instability and alternative telomere lengthening (ALT). PMID:26586439

  7. [Radiation risk to cosmonauts in a flight to Mars].

    PubMed

    Shafirkin, A V; Grigor'ev, Iu G; Kolomenskiĭ, A V

    2004-01-01

    The paper presents results of the 14-year studies (1966-1980) with dogs irradiated by presumable doses of the galactic cosmic rays (GCR) and solar cosmic rays (SCR) that might affect cosmonauts during a flight to Mars. Along with data of chronic experiments with small laboratory animals exposed to a broad variety of dose rates, our data formed a basis for construction of mathematical models of processes of radiation damage to living organisms, and growth of the probability of mammal death or life span reduction caused by repeated acute and chronic irradiation by different dose rates. Described are present-date estimates of equivalent doses from GCR and SCR behind various shields, and radiation risks for cosmonauts of different age on a mission to Mars. Also compared are values of total radiation risks over the length of life, risks of cancer and lifetime reduction after the planetary mission derived by the mathematical modeling and calculation. PMID:15233030

  8. Galactic cosmic ray abundances and spectra behind defined shielding.

    PubMed

    Heinrich, W; Benton, E V; Wiegel, B; Zens, R; Rusch, G

    1994-10-01

    LET spectra have been measured for lunar missions and for several near Earth orbits ranging from 28 degrees to 83 degrees inclination. In some of the experiments the flux of GCR was determined separately from contributions caused by interactions in the detector material. Results of these experiments are compared to model calculations. The general agreement justifies the use of the model to calculate GCR fluxes. The magnitude of variations caused by solar modulation, geomagnetic shielding, and shielding by matter determined from calculated LET spectra is generally in agreement with experimental data. However, more detailed investigations show that there are some weak points in modeling solar modulation and shielding by material. These points are discussed in more detail. PMID:11540030

  9. Optimized shielding for space radiation protection

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Cucinotta, F. A.; Kim, M. H.; Schimmerling, W.

    2001-01-01

    Future deep space mission and International Space Station exposures will be dominated by the high-charge and -energy (HZE) ions of the Galactic Cosmic Rays (GCR). A few mammalian systems have been extensively tested over a broad range of ion types and energies. For example, C3H10T1/2 cells, V79 cells, and Harderian gland tumors have been described by various track-structure dependent response models. The attenuation of GCR induced biological effects depends strongly on the biological endpoint, response model used, and material composition. Optimization of space shielding is then driven by the nature of the response model and the transmission characteristics of the given material.

  10. Optimized Shielding for Space Radiation Protection

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Cucinotta, F. A.; Kim, M.-H. Y.; Schimmerling, W.

    2000-01-01

    Abstract. Future deep space mission and International Space Station exposures will be dominated by the high-charge and -energy (HZE) ions of the Galactic Cosmic Rays (GCR). A few mammalian systems have been extensively tested over a broad range of ion types and energies. For example, C3H10T1/2 cells, V79 cells, and Harderian gland tumors have been described by various track-structure dependent response models. The attenuation of GCR induced biological effects depends strongly on the biological endpoint, response model used, and material composition. Optimization of space shielding is then driven by the nature of the response model and the transmission characteristics of the given material.

  11. The Heavy Nuclei eXplorer (HNX) Mission

    NASA Technical Reports Server (NTRS)

    Binns, W. R.; Adams, J. H.; Barbier, L. M.; Craig, N.; Cummings, A. C.; Cummings, J. R.; Doke, T.; Hasebe, N.; Hayashi, T.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    The primary scientific objectives of HNX, which was recently selected by NASA for a Small Explorer (SMEX) Mission Concept Study, are to measure the age of the galactic cosmic rays (GCR) since nucleosynthesis, determine the injection mechanism for the GCR accelerator (Volatility or FIP), and study the mix of nucleosynthetic processes that contribute to the source of GCRs. The experimental goal of HNX is to measure the elemental abundances of all individual stable nuclei from neon through the actinides and possibly beyond. HNX is composed of two instruments: ECCO, which measures elemental abundances of nuclei with Z greater than or equal to 72, and ENTICE. which measures elemental abundances of nuclei with Z between 10 and 82. We describe the mission and the science that can be addressed by HNX.

  12. Space Radiation and Exploration - Information for the Augustine Committee Review

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis; Semones, Edward; Kim, Myung-Hee; Jackson, Lori

    2009-01-01

    Space radiation presents significant health risks including mortality for Exploration missions: a) Galactic cosmic ray (GCR) heavy ions are distinct from radiation that occurs on Earth leading to different biological impacts. b) Large uncertainties in GCR risk projections impact ability to design and assess mitigation approaches and select crew. c) Solar Proton Events (SPEs) require new operational and shielding approaches and new biological data on risks. Risk estimates are changing as new scientific knowledge is gained: a) Research on biological effects of space radiation show qualitative and quantitative differences with X- or gamma-rays. b) Expert recommendations and regulatory policy are changing. c) New knowledge leads to changes in estimates for the number of days in space to stay below Permissible Exposure Limits (PELS).

  13. Solar Particle Events Observed by the Odyssey MARIE Instrument at Mars: Dose and Model Calculations

    NASA Technical Reports Server (NTRS)

    Cleghorn, T. F.; Saganti, P. B.; Zeitlin, C. J.; Cucinotta, F. A.

    2003-01-01

    One of the primary concerns prior to human exploration of Mars is the need to accurately characterize the charged particle radiation environment both for the surface stay, and for the transit period to and from the planet. The Odyssey spacecraft, currently in Mars orbit includes a charged particle radiation detector, MARIE, which can measure particle fluxes with energies above approx. 30 MeV and charges between 1 and 10. Two classes of particles are of particular interest: the Galactic Cosmic Rays, (GCR), and those charged particles associated with Solar Particle Events, (SPE). The GCR are present continuously throughout the solar activity cycle, and their numbers vary inversely with the level of solar activity. They are characteristically more energetic than those particles originating from solar activity, and hence less influences by the solar magnetic field.

  14. Preliminary Design of a Galactic Cosmic Ray Shielding Materials Testbed for the International Space Station

    NASA Technical Reports Server (NTRS)

    Gaier, James R.; Berkebile, Stephen; Sechkar, Edward A.; Panko, Scott R.

    2012-01-01

    The preliminary design of a testbed to evaluate the effectiveness of galactic cosmic ray (GCR) shielding materials, the MISSE Radiation Shielding Testbed (MRSMAT) is presented. The intent is to mount the testbed on the Materials International Space Station Experiment-X (MISSE-X) which is to be mounted on the International Space Station (ISS) in 2016. A key feature is the ability to simultaneously test nine samples, including standards, which are 5.25 cm thick. This thickness will enable most samples to have an areal density greater than 5 g/sq cm. It features a novel and compact GCR telescope which will be able to distinguish which cosmic rays have penetrated which shielding material, and will be able to evaluate the dose transmitted through the shield. The testbed could play a pivotal role in the development and qualification of new cosmic ray shielding technologies.

  15. Cosmogenic 44Ti in meteorites and century scale solar modulation.

    PubMed

    Bonino, G; Cini Castagnoli, G; Taricco, C; Bhandari, N

    1994-10-01

    The galactic cosmic ray (GCR) flux is modulated by solar activity: 11 and 22 year cycles are well established. Meteorites offer the possibility of studying longer cycles in the interplanetary space, due to GCR nuclear interactions. 44Ti cosmogenic isotope produced in meteorites is suitable for detecting a century scale modulation. So far reliable measurements of 44Ti in the samples are scarce, the radioisotope concentration being very low. A gamma-ray sensitive spectrometer has been set up in the underground laboratory of Monte dei Cappuccini. The system consists of a 2 kg HPGe detector inside a 28 kg NaI well. The system has a background of approximately 1 count/day (in coincidence mode) in the 44Ti region. We present here the results obtained on the Rio Negro meteorite, which fell in the year 1934. PMID:11540026

  16. Cosmic Ray Modulation in the Outer Heliosphere During the Minimum of Solar Cycle 23/24

    NASA Technical Reports Server (NTRS)

    Adams, James H., Jr.; Florinski, V.; Washimi, H.; Pogorelov, N. V.

    2011-01-01

    We report a next generation model of galactic cosmic ray (GCR) transport in the three dimensional heliosphere. Our model is based on an accurate three-dimensional representation of the heliospheric interface. This representation is obtained by taking into account the interaction between partially ionized, magnetized plasma flows of the solar wind and the local interstellar medium. Our model reveals that after entering the heliosphere GCRs are stored in the heliosheath for several years. The preferred GCR entry locations are near the nose of the heliopause and at high latitudes. Low-energy (hundreds of MeV) galactic ions observed in the heliosheath have spent, on average, a longer time in the solar wind than those observed in the inner heliosphere, which would explain their cooled-off spectra at these energies. We also discuss radial gradients in the heliosheath and the implications for future Voyager observations.

  17. Revisited modeling of Titan’s middle atmosphere electrical conductivity

    NASA Astrophysics Data System (ADS)

    Mishra, Alabhya; Michael, Marykutty; Tripathi, Sachchida Nand; Béghin, Christian

    2014-08-01

    The atmospheric electrical conductivity measured by the Permittivity, Wave and Altimetry (PWA) subsystem on board the Huygens probe, during the landing mission on Titan, has been modeled in the present work. Previous modeling studies showed a Galactic Cosmic Ray (GCR) peak of conductivity at a higher altitude and a quantitative overestimation in the altitude range 0-100 km compared to that observed by the PWA instrument. Recently the PWA data was revisited and provided new constraints on the conductivity at altitudes 100-180 km. Because the aerosols in the atmosphere are known to alter the electron concentration, using a detailed distribution of the aerosols at all altitudes, the electron conductivity has been calculated in the altitude range 0-180 km. By using a variable range of photoemission threshold for the aerosols, the present model is able to reasonably predict the altitude at which the GCR peak of conductivity occurs and to meet the new constraints for the conductivity profile.

  18. Variations of Dose Rate Observed by MSL/RAD in Transit to Mars

    NASA Astrophysics Data System (ADS)

    Guo, Jingnan; Zeitlin, Cary; Wimmer-Schweingruber, Robert; Hassler, Donald; Posner, Arik; Heber, Bernd; Koehler, Jan; Rafkin, Scot; Ehresmann, Bent; Appel, Jan; Boehm, Eckart; Boettcher, Stephan; Burmeister, Soenke; Brinza, David; Lohf, Henning; Martin, Cesar; Reitz, Guenther

    2015-04-01

    The Radiation Assessment Detector (RAD), on board Mars Science Laboratory's (MSL) rover Curiosity, measured the radiation dose rate during the 253-day cruise phase to Mars, along with a broad spectrum of energetic particles. RAD carried out the first radiation measurements inside a spacecraft from Earth to Mars. It observed not only the impulsive enhancement of dose rate during Solar Particle Events (SPE) but also a gradual evolution of the Galactic Cosmic Ray (GCR) -induced radiation dose rate. The primary GCR flux rate is modulated by the solar magnetic field, which correlates with long-term solar activities and heliospheric rotation. The correlation between solar modulation and the dose rate measured by RAD has been analyzed, and the results have been used to estimate the dose and dose equivalent rates under different solar modulation conditions. Such estimations could form the basis for a reliable model of the radiation environment related to future human missions to Mars.

  19. Predicting space climate change

    NASA Astrophysics Data System (ADS)

    Barnard, L.; Lockwood, M.; Hapgood, M. A.; Owens, M. J.; Davis, C. J.; Steinhilber, F.

    2011-08-01

    The recent decline in the open magnetic flux of the Sun heralds the end of the Grand Solar Maximum (GSM) that has persisted throughout the space age, during which the largest-fluence Solar Energetic Particle (SEP) events have been rare and Galactic Cosmic Ray (GCR) fluxes have been relatively low. In the absence of a predictive model of the solar dynamo, we here make analogue forecasts by studying past variations of solar activity in order to evaluate how long-term change in space climate may influence the hazardous energetic particle environment of the Earth in the future. We predict the probable future variations in GCR flux, near-Earth interplanetary magnetic field (IMF), sunspot number, and the probability of large SEP events, all deduced from cosmogenic isotope abundance changes following 24 GSMs in a 9300-year record.

  20. Emerging Radiation Health-Risk Mitigation Technologies

    NASA Astrophysics Data System (ADS)

    Wilson, J. W.; Cucinotta, F. A.; Schimmerling, W.

    2004-02-01

    Past space missions beyond the confines of the Earth's protective magnetic field have been of short duration and protection from the effects of solar particle events was of primary concern. The extension of operational infrastructure beyond low-Earth orbit to enable routine access to more interesting regions of space will require protection from the hazards of the accumulated exposures of Galactic Cosmic Rays (GCR). There are significant challenges in providing protection from the long-duration exposure to GCR: the human risks to the exposures are highly uncertain and safety requirements places unreasonable demands in supplying sufficient shielding materials in the design. A vigorous approach to future radiation health-risk mitigation requires a triage of techniques (using biological and technical factors) and reduction of the uncertainty in radiation risk models. The present paper discusses the triage of factors for risk mitigation with associated materials issues and engineering design methods.

  1. Effects of radiobiological uncertainty on vehicle and habitat shield design for missions to the moon and Mars

    NASA Technical Reports Server (NTRS)

    Wilson, John W.; Nealy, John E.; Schimmerling, Walter; Cucinotta, Francis A.; Wood, James S.

    1993-01-01

    Some consequences of uncertainties in radiobiological risk due to galactic cosmic ray (GCR) exposure are analyzed for their effect on engineering designs for the first lunar outpost and a mission to explore Mars. This report presents the plausible effect of biological uncertainties, the design changes necessary to reduce the uncertainties to acceptable levels for a safe mission, and an evaluation of the mission redesign cost. Estimates of the amount of shield mass required to compensate for radiobiological uncertainty are given for a simplified vehicle and habitat. The additional amount of shield mass required to provide a safety factor for uncertainty compensation is calculated from the expected response to GCR exposure. The amount of shield mass greatly increases in the estimated range of biological uncertainty, thus, escalating the estimated cost of the mission. The estimates are used as a quantitative example for the cost-effectiveness of research in radiation biophysics and radiation physics.

  2. Radiation Measured with Different Dosimeters for ISS-Expedition 18-19/ULF2 on Board International Space Station during Solar Minimum

    NASA Technical Reports Server (NTRS)

    Zhou, Dazhuang; Gaza, R.; Roed, Y.; Semones, E.; Lee, K.; Steenburgh, R.; Johnson, S.; Flanders, J.; Zapp, N.

    2010-01-01

    Radiation field of particles in low Earth orbit (LEO) is mainly composed of galactic cosmic rays (GCR), solar energetic particles and particles in SAA (South Atlantic Anomaly). GCR are modulated by solar activity, at the period of solar minimum activity, GCR intensity is at maximum and the main contributor for space radiation is GCR. At present for space radiation measurements conducted by JSC (Johnson Space Center) SRAG (Space Radiation Analysis Group), the preferred active dosimeter sensitive to all LET (Linear Energy Transfer) is the tissue equivalent proportional counter (TEPC); the preferred passive dosimeters are thermoluminescence dosimeters (TLDs) and optically stimulated luminescence dosimeters (OSLDs) sensitive to low LET as well as CR-39 plastic nuclear track detectors (PNTDs) sensitive to high LET. For the method using passive dosimeters, radiation quantities for all LET can be obtained by combining radiation results measured with TLDs/OSLDs and CR-39 PNTDs. TEPC, TLDs/OSLDs and CR-39 detectors were used to measure the radiation field for the ISS (International Space Station) - Expedition 18-19/ULF2 space mission which was conducted from 15 November 2008 to 31 July 2009 - near the period of the recent solar minimum activity. LET spectra (differential and integral fluence, absorbed dose and dose equivalent) and radiation quantities were measured for positions TEPC, TESS (Temporary Sleeping Station, inside the polyethylene lined sleep station), SM-P 327 and 442 (Service Module - Panel 327 and 442). This paper presents radiation LET spectra measured with TEPC and CR-39 PNTDs and radiation dose measured with TLDs/OSLDs as well as the radiation quantities combined from results measured with passive dosimeters.

  3. Space Radiation Hazards on Human Missions to the Moon and Mars

    NASA Astrophysics Data System (ADS)

    Townsend, L.

    2004-12-01

    One of the most significant health risks for humans exploring Earth's moon and Mars is exposure to the harsh space radiation environment. Crews on these exploration missions will be exposed to a complex mixture of very energetic particles. Chronic exposures to the ever-present background galactic cosmic ray (GCR) spectrum consisting of various fluxes of all naturally - occurring chemical elements are combined with infrequent, possibly acute exposures to large fluxes of solar energetic particles, consisting of protons and heavier particles. The GCR environment is primarily a concern for stochastic effects, such as the induction of cancer, with subsequent mortality in many cases, and late deterministic effects, such as cataracts and possible damage to the central nervous system. An acute radiation syndrome response ("radiation sickness") is not possible from the GCR environment since the organ doses are well below levels of concern. Unfortunately, the actual risks of cancer induction and mortality for the very important high-energy heavy ion component of the GCR spectrum are essentially unknown. The sporadic occurrence of extremely large solar energetic particle events, usually associated with intense solar activity, is also a major concern for Lunar and Mars missions because of the possible manifestation of acute effects from the accompanying high doses of such radiations, especially acute radiation syndrome effects such as nausea, emesis, hemorrhaging or possibly even death. Large solar energetic particle events can also contribute significantly to crew risks from cancer mortality. In this presentation an overview of current estimates of critical organ doses and equivalent doses for crews of Lunar and Mars bases and on those on transits between Earth and Mars is presented. Possible methods of mitigating these radiation exposures by shielding, thereby reducing the associated health risks to crews, are also described.

  4. Fabrication of Regolith-Derived Radiation Shield Project

    NASA Technical Reports Server (NTRS)

    Zeitlin, Nancy; Mantovani, James G.; Townsend, Ivan

    2015-01-01

    Mars and asteroids have little or no atmosphere, and do not possess a magnetosphere that can protect humans, mechanisms and electronics from damaging Galactic Cosmic Radiation (GCR) and solar particle events (SPE) as does the Earth. These types of space radiation present one of the highest risks to a human crew during interplanetary journeys and to onboard electronics. This project aims to evaluate the effectiveness of carbonaceous asteroid materials as a potential radiation shielding material.

  5. ISOLATED WOLF-RAYET STARS AND O SUPERGIANTS IN THE GALACTIC CENTER REGION IDENTIFIED VIA PASCHEN-{alpha} EXCESS

    SciTech Connect

    Mauerhan, J. C.; Stolovy, S. R.; Cotera, A.; Dong, H.; Wang, Q. D.; Morris, M. R.; Lang, C.

    2010-12-10

    We report the discovery of 19 hot, evolved, massive stars near the Galactic center region (GCR). These objects were selected for spectroscopy owing to their detection as strong sources of Paschen-{alpha} (P{alpha}) emission-line excess, following a narrowband imaging survey of the central 0.{sup 0}65 x 0.{sup 0}25 (l, b) around Sgr A* with the Hubble Space Telescope. Discoveries include six carbon-type (WC) and five nitrogen-type (WN) Wolf-Rayet stars, six O supergiants, and two B supergiants. Two of the O supergiants have X-ray counterparts having properties consistent with solitary O stars and colliding-wind binaries. The infrared photometry of 17 stars is consistent with the Galactic center distance, but 2 of them are located in the foreground. Several WC stars exhibit a relatively large infrared excess, which is possibly thermal emission from hot dust. Most of the stars appear scattered throughout the GCR, with no relation to the three known massive young clusters; several others lie near the Arches and Quintuplet clusters and may have originated within one of these systems. The results of this work bring the total sample of Wolf-Rayet (WR) stars in the GCR to 88. All sources of strong P{alpha} excess have been identified in the area surveyed with HST, which implies that the sample of WN stars in this region is near completion, and is dominated by late (WNL) types. The current WC sample, although probably not complete, is almost exclusively dominated by late (WCL) types. The observed WR subtype distribution in the GCR is a reflection of the intrinsic rarity of early subtypes (WNE and WCE) in the inner Galaxy, an effect that is driven by metallicity.

  6. Krylov Subspace and Multigrid Methods Applied to the Incompressible Navier-Stokes Equations

    NASA Technical Reports Server (NTRS)

    Vuik, C.; Wesseling, P.; Zeng, S.

    1996-01-01

    We consider numerical solution methods for the incompressible Navier-Stokes equations discretized by a finite volume method on staggered grids in general coordinates. We use Krylov subspace and multigrid methods as well as their combinations. Numerical experiments are carried out on a scalar and a vector computer. Robustness and efficiency of these methods are studied. It appears that good methods result from suitable combinations of GCR and multigrid methods.

  7. Multi-Scale Model of Galactic Cosmic Ray Effects on the Hippocampus

    NASA Astrophysics Data System (ADS)

    Cucinotta, Francis

    An important concern for risk assessment from galactic cosmic ray (GCR) exposures is impacts to the central nervous systems including changes in cognition, and associations with increased risk of Alzheimer’s disease (AD). AD, which affects about 50 percent of the population above age 80-yr, is a degenerative disease that worsens with time after initial onset leading to death, and has no known cure. AD is difficult to detect at early stages, and the small number of epidemiology studies that have considered the possibility have not identified an association with low dose radiation. However, experimental studies in transgenic mice suggest the possibility exits. We discuss modeling approaches to consider mechanisms whereby GCR would accelerate the occurrence of AD to earlier ages. Biomarkers of AD include Amyloid beta plaques, and neurofibrillary tangles (NFT) made up of aggregates of the hyper-phosphorylated form of the micro-tubule associated, tau protein. Related markers include synaptic degeneration, dendritic spine loss, and neuronal cell loss through apoptosis. GCR may affect these processes by causing oxidative stress, aberrant signaling following DNA damage, and chronic neuro-inflammation. Cell types considered in multi-scale models are neurons, astrocytes, and microglia. We developed biochemical and cell kinetics models of DNA damage signaling related to glycogen synthase kinase-3 beta and neuro-inflammation, and considered approaches to develop computer simulations of GCR induced cell interactions and their relationships to Amyloid beta plaques and NFTs. Comparison of model results to experimental data for the age specific development of plaques in transgenic mice and predictions of space radiation effects will be discussed.

  8. Status of experimental data base development relevant to spaceradiation transport and protection

    SciTech Connect

    Heilbronn, Lawrence H.; Guetersloh, Stephen; Zeitlin, Cary; Miller, Jack

    2004-04-01

    This report describes the highlights and progress made in aprogram of measurements studying radiation transport through materials ofinterest to NASA. All measurements were preformed at acceleratorfacilities, primarily using GCR-like heavy-ion beams incident uponvarious elemental and composite targets. Both primary and secondaryparticles exiting the target were measured. The secondary particlesinclude both charged particles and neutrons. These measurements serve asuseful benchmarks and input to transport model calculations.

  9. MCNP6 Cosmic-Source Option

    SciTech Connect

    McKinney, Gregg W; Armstrong, Hirotatsu; James, Michael R; Clem, John; Goldhagen, Paul

    2012-06-19

    MCNP is a Monte Carlo radiation transport code that has been under development for over half a century. Over the last decade, the development team of a high-energy offshoot of MCNP, called MCNPX, has implemented several physics and algorithm improvements important for modeling galactic cosmic-ray (GCR) interactions with matter. In this presentation, we discuss the latest of these improvements, a new Cosmic-Source option, that has been implemented in MCNP6.

  10. Comparisons of Integrated Radiation Transport Models with Microdosimetry Data in Spaceflight

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Nikjoo, H.; Kim, M. Y.; Hu, X.; Dicello, J. F.; Pisacane, V. L.

    2006-01-01

    Astronauts are exposed to galactic cosmic rays (GCR), trapped protons, and possible solar particle events (SPE) during spaceflight. For such complicated mixtures of radiation types and kinetic energies, tissue equivalent proportional counters (TEPC's) represent a simple time-dependent approach for radiation monitoring. Of interest in radiation protection is the average quality factor of a radiation field defined as a function of linear energy transfer, LET, Q(sub ave)(LET). However TEPC's measure the average quality factors as a function of lineal energy (y), Q(sub ave)(y) defined as the average energy deposition in a volume divided by the average chord length of the volume. Lineal energy, y deviates from LET due to energy straggling, delta-ray escape or entry, and nuclear fragments produced in the detector. Using integrated space radiation models that includes the transport code HZETRN/BRYNTRN, the quantum nuclear interaction model, QMSFRG, and results from Monte-Carlo track simulations of TEPC's response to ions, we consider comparisons of model calculations to TEPC results from NASA missions in low Earth orbit and make predictions for lunar and Mars missions. Good agreement between the model and measured spectra from past NASA missions is found. A finding of this work is that TEPC's values for trapped or solar protons of Q(sub ave)(y) range from 1.9-2.5, overestimating Q(sub ave)(LET), which ranges from 1.4-1.6 with both quantities increasing with shielding depth due to nuclear secondaries Comparisons for the complete GCR spectra show that Q(sub ave)(LET) for GCR is approximately 3.5-4.5, while TEPC's measure 2.9-3.4 for Q(sub ave)(y) with the GCR values decreasing with depth as heavy ions are absorbed in shielding material. Our results support the use of TEPC's for space radiation environmental monitoring when computational analysis is used for proper data interpretation.

  11. Polymeric Materials With Additives for Durability and Radiation Shielding in Space

    NASA Technical Reports Server (NTRS)

    Kiefer, Richard

    2011-01-01

    Polymeric materials are attractive for use in space structures because of their light weight and high strength In addition, polymers are made of elements with low atomic numbers (Z), primarily carbon (C), hydrogen (H), oxygen (0), and nitrogen (N) which provide the best shielding from galactic cosmic rays (GCR) (ref. 1). Galactic cosmic rays are composed primarily of nuclei (i.e., fully ionized atoms) plus a contribution of about 2% from electrons and positrons. There is a small but significant component of GCR particles with high charge (Z > 10) and high energy (E >100 GeV) (ref. 2). These so-called HZE particles comprise only 1 to 2% of the cosmic ray fluence but they interact with very high specific ionization and contribute 50% of the long- term dose to humans. The best shield for this radiation would be liquid hydrogen, which is not feasible. For this reason, hydrogen-containing polymers make the most effective practical shields. Moreover, neutrons are formed in the interactions of GCR particles with materials. Neutrons can only lose energy by collisions or reactions with a nucleus since they are uncharged. This is a process that is much less probable than the Coulombic interactions of charged particles. Thus, neutrons migrate far from the site of the reaction in which they were formed. This increases the probability of neutrons reaching humans or electronic equipment. Fast neutrons (> 1 MeV) can interact with silicon chips in electronic equipment resulting in the production of recoil ions which can cause single event upsets (SEU) in sensitive components (ref. 3). Neutrons lose energy most effectively by elastic collisions with light atoms, particularly hydrogen atoms. Therefore, hydrogen-containing polymers are not only effective in interacting with GCR particles; they are also effective in reducing the energy of the neutrons formed in the interactions.

  12. Minimizing Astronauts' Risk from Space Radiation during Future Lunar Missions

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; Hayat, Mathew; Nounu, Hatem N.; Feiveson, Alan H.; Cucinotta, Francis A.

    2007-01-01

    This viewgraph presentation reviews the risk factors from space radiation for astronauts on future lunar missions. Two types of radiation are discussed, Galactic Cosmic Radiation (GCR) and Solar Particle events (SPE). Distributions of Dose from 1972 SPE at 4 DLOCs inside Spacecraft are shown. A chart with the organ dose quantities is also given. Designs of the exploration class spacecraft and the planned lunar rover are shown to exhibit radiation protections features of those vehicles.

  13. Radiation Measured with Different Dosimeters for ISS-Expedition 18-19/ULF2 on Board International Space Station during Solar Minimum

    NASA Astrophysics Data System (ADS)

    Zhou, Dazhuang

    Radiation field of particles in low Earth orbit (LEO) is mainly composed of galactic cosmic rays (GCR), solar energetic particles and particles in SAA (South Atlantic Anomaly). GCR are modulated by solar activity, at the period of solar minimum activity, GCR intensity is at maximum and the main contributor for space radiation is GCR. At present for space radiation measurements conducted by JSC (Johnson Space Center) -SRAG (Space Radiation Analysis Group), the preferred active dosimeter sensitive to all LET (Linear Energy Transfer) is the tissue equivalent proportional counter (TEPC); the preferred passive dosimeters are thermoluminescence dosimeters (TLDs) and optically stimulated luminescence dosimeters (OSLDs) sensitive to low LET as well as CR-39 plastic nuclear track detectors (PNTDs) sensitive to high LET. For the method using passive dosimeters, radiation quantities for all LET can be obtained by combining radiation results measured with TLDs/OSLDs and CR-39 PNTDs. TEPC, TLDs/OSLDs and CR-39 detectors were used to measure the radiation field for the ISS (International Space Station) -Expedition 18-19/ULF2 space mission which was conducted from 15 November 2008 to 31 July 2009 -near the period of the recent solar minimum activity. LET spectra (differential and integral fluence, absorbed dose and dose equivalent) and radiation quantities were measured for positions TEPC, TESS (Temporary Sleeping Station, inside the polyethylene lined sleep station), SM-P 327 and 442 (Service Module -Panel 327 and 442). This paper presents radiation LET spectra measured with TEPC and CR-39 PNTDs and radiation dose measured with TLDs/OSLDs as well as the radiation quantities combined from results measured with passive dosimeters.

  14. Expression of 11?-hydroxysteroid dehydrogenase type 1 and glucocorticoid receptors in reproductive tissue of male horses at different stages of sexual maturity.

    PubMed

    Herrera-Luna, C V; Budik, S; Helmreich, M; Walter, I; Aurich, C

    2013-04-01

    Glucocorticoids (GCs) as mediators of the stress response may affect Leydig cell function by inhibiting either luteinizing hormone receptor expression or testosterone biosynthesis. The isozymes 11?-hydroxysteroid dehydrogenase (11?HSD) 1 and 11?HSD2 control the intracellular cortisol levels. Little is known about the effects of stress on fertility in the equine. The objective of the present study was to determine the presence and cellular localization of glucocorticoid receptors (GCR) and glucocorticoid-metabolizing enzymes (11?HSD1 and 11?HSD2) in equine epididymal and testicular tissue with special regard to sexual maturation. Testicular and epididymal tissue was collected from 21 healthy stallions, and four age groups were designed: pre-pubertal, young, mature and older horses. Immunohistochemistry (IHC) analysis and quantitative real-time PCR (qRT-PCR) were used. Pre-pubertal horses showed higher testicular gene expression of 11?HSD1, 11?HSD2 and GCR than horses of all other groups (p < 0.05). A positive intranuclear immunoreaction for GCR was seen in epithelial cells of caput, corpus and cauda epididymidis and in Leydig cells. Significant differences (p < 0.05) between age groups occurred. The number of Leydig cells staining positive for GCR was highest in immature stallions (p < 0.05). The enzyme 11?HSD1 was localized in epithelial cells of the caput and corpus epididymidis and in Leydig cells. As determined by enzyme assay, nicotinamide adenine dinucleotide (NAD)-dependant dehydrogenase (oxidation) activity was not detected in testicular tissue from immature stallions but in all other age groups (n = 3 per group). Results of this study suggest a contribution of GCs to maturation of male reproductive tissue in horses. In mature stallions, expression of 11?HSD enzymes and the oxidative 11?HSD activity in Leydig cells and epididymal basal and principal cells suggest a protective role on these tissues contributing to physiological intracellular glucocorticoid concentrations. PMID:22734562

  15. The Feasibility of Multipole Electrostatic Radiation Shielding

    NASA Technical Reports Server (NTRS)

    Metzger, Philip T.; Lane, John E.; Youngquist, Robert C.

    2004-01-01

    Although passive shielding appears to be the only workable solution for galactic cosmic radiation (GCR), active shielding may play an important augmenting role to control the dose from solar particle events (SPEs). It has been noted that, to meet the guidelines of NCRP Report No. 98 through the six SPEs of 1989, a crew member would need roughly double the passive shielding that is necessary to control the GCR dose . This would dramatically increase spacecraft mass, and so it has been proposed that a small but more heavily shielded storm shelter may be used to protect the crew during SPEs. Since a gradual SPE may last 5 or more days, staying in a storm shelter may be psychologically and physiologically distressing to the crew. Storm shelters do not provide shielding for the spacecraft itself against the SPE radiation, and radiation damage to critical electronics may result in loss of mission and life. Single-event effects during the radiation storm may require quick crew response to maintain the integrity of the spacecraft, and confining the crew to a storm shelter prohibits their attending to the spacecraft at the precise time when that attention is needed the most. Active shielding cannot protect against GCR because the particle energies are too high. Although lower energy particles are easier to stop in a passive shield, such shielding is more satisfactory against GCR than against SPE radiation because of the tremendous difference in their initial fluences. Even a small fraction of the SPE fluence penetrating the passive shielding may result in an unacceptably high dose. Active shielding is more effective than passive shielding against SPE radiation because it offers 100% shielding effectiveness up to the cutoff energy, and significant shielding effectiveness beyond the cutoff as well.

  16. On time variations of the intensity of galactic cosmic rays for the recent billion years from the data on exposure ages of iron meteorites

    NASA Astrophysics Data System (ADS)

    Alexeev, V. A.

    2016-01-01

    To ascertain probable variations of the intensity of galactic cosmic rays (GCR) for the recent billion years, the distribution of exposure ages T of iron meteorites has been analyzed. We considered all ~80 values of ages from the data by Voshage and Feldmann (1979), Voshage et al. (1983), and Voshage (1984), as well as a set of values obtained from the correction for eliminating the meteorites formed in a single collision. To correct the data, the Akaike information criterion was used. For the distributions of the phase values Ph = T/t-int( T/t), the dependence of the criterion χ 2 on the presumable period t in the exposure age variations was analyzed. For t ~ 400-500 Myr and, partly, for t ~ 150 Myr, the significant deviations of this criterion from the corresponding mean values were found. To clear up the influence of the GCR intensity variations on the age distribution, the numerical models were calculated with an account of the set of ages randomly distributed in the interval of 0-1000 Myr with the presumptive mean lifetime of iron meteorites in outer space τ = 700 Myr. It has been ascertained that, for variations with a period of t = 450 Myr, the distribution of exposure ages of the model set is similar to that found for iron meteorites. The obtained data suggest that the GCR intensity variations with a period of approximately 400-500 Myr have probably existed during the recent billion years. These variations may be caused by periodic passages of the Solar System through spiral arms of the Galaxy. It has been shown that the earlier discussed changes in the GCR intensity with a period of ~150 Myr (Shaviv, 2002; 2003; Scherer et al., 2006) are less defined.

  17. Sunspot activity and cosmic ray modulation at 1 a.u. for 1900-2013

    NASA Astrophysics Data System (ADS)

    Ahluwalia, H. S.

    2014-10-01

    The descent of sunspot cycle 23 to an unprecedented minimum of long duration in 2006-2009 led to a prolonged galactic cosmic ray (GCR) recovery to the highest level observed in the instrumental era for a variety of energetic charged particle species on Earth, over a wide range of rigidities. The remarkable GCR increase measured by several ground-based, balloon-borne, and detectors on a satellite is described and discussed. It is accompanied by a decrease in solar wind velocity and interplanetary magnetic field at 1 a.u., reaching the lowest values since measurements of the solar wind began in October 1963; the solar polar field strength (μT) measured at the Wilcox Solar Observatory (WSO) is also significantly reduced compared to prior cycles since the start of the program in 1976, the polar field in the northern hemisphere reversed in June 2012 and again in February 2014, that in the southern hemisphere reversed in July 2013. If updates of WSO data confirm the second reversal in northern solar hemisphere, it would pose a serious challenge to the Dynamo Theory. The long-term change in solar behavior may have begun in 1992, perhaps earlier. The physical underpinnings of these solar changes need to be understood and their effect on GCR modulation processes clarified. The study discusses the recent phenomena in the context of GCR modulation since 1900. These happenings affected our empirical predictions for the key parameters for the next two sunspot cycles (they may be progressively less active than sunspot cycle 24) but it enhanced support for our prediction that solar activity is descending into a Dalton-like grand minimum in the middle of the twentyfirst century, reducing the frequency of the coronal mass ejections; they determine the space weather affecting the quality of life on Earth, radiation dose for hardware and human activities in space as well as the frequency of large Forbush decreases at 1 a.u.

  18. An Algorithm for the Transport of Anisotropic Neutrons

    NASA Technical Reports Server (NTRS)

    Tweed, J.

    2005-01-01

    One major obstacle to human space exploration is the possible limitations imposed by the adverse effect of long-term exposure to the space environment. Even before human spaceflight began, the potentially brief exposure of astronauts to the very intense random solar particle events (SPE) were of great concern. A new challenge appears in deep space exploration from exposure to the low-intensity heavy-ion flux of the galactic cosmic rays (GCR) since the missions are of long duration and the accumulated GCR exposures can be high. Because cancer induction rates increase behind low to rather large thicknesses of aluminum shielding, according to available biological data on mammalian exposures to GCR like ions, the shield requirements for a Mars mission are prohibitively expensive in terms of mission launch costs. Therefore, a critical issue in the Human Exploration and Development of Space enterprise is cost effective mitigation of risk associated with ionizing radiation exposure. In order to estimate astronaut risk to GCR exposure and associated cancer risks and health hazards, it is necessary to do shield material studies. To determine an optimum radiation shield material it is necessary to understand nuclear interaction processes such as fragmentation and secondary particle production which is a function of energy dependent cross sections. This requires knowledge of material transmission characteristics either through laboratory testing or improved theoretical modeling. Here ion beam transport theory is of importance in that testing of materials in the laboratory environment generated by particle accelerators is a necessary step in materials development and evaluation for space use. The approximations used in solving the Boltzmann transport equation for the space setting are often not sufficient for laboratory work and those issues are a major emphasis of the present work.

  19. Identification of Quantitative Trait Loci Associated with Rice Eating Quality Traits Using a Population of Recombinant Inbred Lines Derived from a Cross between Two Temperate japonica Cultivars

    PubMed Central

    Kwon, Soon-Wook; Cho, Young-Chan; Lee, Jeong-Heui; Suh, Jung-Pi; Kim, Jeong-Ju; Kim, Myeong-Ki; Choi, Im-Soo; Hwang, Hung-Goo; Koh, Hee-Jong; Kim, Yeon-Gyu

    2011-01-01

    Improved eating quality is a major breeding target in japonica rice due to market demand. In this study, we performed genetic analysis to identify quantitative trait loci (QTLs) that control rice eating quality traits using 192 recombinant inbred lines (RILs) derived from a cross between two japonica cultivars, ‘Suweon365’ and ‘Chucheongbyeo’. We evaluated the stickiness (ST) and overall evaluation (OE) of cooked rice using a sensory test, the glossiness of cooked rice (GCR) using a Toyo-taste meter, and measured the amylose content (AC), protein content (PC), alkali digestion value (ADV), and days to heading (DH) of the RILs in the years 2006 and 2007. Our analysis revealed 21 QTLs on chromosomes 1, 4, 6, 7, 8, and 11. QTLs on chromosomes 6, 7, and 8 were detected for three traits related to eating quality in both years. QTLs for ST and OE were identified by a sensory test in the same region of the QTLs for AC, PC, ADV, GCR and DH on chromosome 8. QTL effects on the GCR were verified using QTL-NILs (near-isogenic lines) of BC3F4-6 in the Suweon365 background, a low eating quality variety, and some BC1F3 lines. Chucheongbyeo alleles at QTLs on chromosomes 7 and 8 increased the GCR in the NILs and backcrossed lines. The QTLs identified by our analysis will be applicable to future marker-assisted selection (MAS) strategies for improving the eating quality of japonica rice. PMID:21360198

  20. Radiation risk predictions for Space Station Freedom orbits

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Atwell, William; Weyland, Mark; Hardy, Alva C.; Wilson, John W.; Townsend, Lawrence W.; Shinn, Judy L.; Katz, Robert

    1991-01-01

    Risk assessment calculations are presented for the preliminary proposed solar minimum and solar maximum orbits for Space Station Freedom (SSF). Integral linear energy transfer (LET) fluence spectra are calculated for the trapped proton and GCR environments. Organ dose calculations are discussed using the computerized anatomical man model. The cellular track model of Katz is applied to calculate cell survival, transformation, and mutation rates for various aluminum shields. Comparisons between relative biological effectiveness (RBE) and quality factor (QF) values for SSF orbits are made.