Sample records for germcode gcr event-based

  1. GCR environmental models II: Uncertainty propagation methods for GCR environments

    NASA Astrophysics Data System (ADS)

    Slaba, Tony C.; Blattnig, Steve R.

    2014-04-01

    In order to assess the astronaut exposure received within vehicles or habitats, accurate models of the ambient galactic cosmic ray (GCR) environment are required. Many models have been developed and compared to measurements, with uncertainty estimates often stated to be within 15%. However, intercode comparisons can lead to differences in effective dose exceeding 50%. This is the second of three papers focused on resolving this discrepancy. The first paper showed that GCR heavy ions with boundary energies below 500 MeV/n induce less than 5% of the total effective dose behind shielding. Yet, due to limitations on available data, model development and validation are heavily influenced by comparisons to measurements taken below 500 MeV/n. In the current work, the focus is on developing an efficient method for propagating uncertainties in the ambient GCR environment to effective dose values behind shielding. A simple approach utilizing sensitivity results from the first paper is described and shown to be equivalent to a computationally expensive Monte Carlo uncertainty propagation. The simple approach allows a full uncertainty propagation to be performed once GCR uncertainty distributions are established. This rapid analysis capability may be integrated into broader probabilistic radiation shielding analysis and also allows error bars (representing boundary condition uncertainty) to be placed around point estimates of effective dose.

  2. 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.

  3. Illuminant Multiplexed Imaging: Special Effects using GCR

    E-print Network

    Sharma, Gaurav

    Illuminant Multiplexed Imaging: Special Effects using GCR Gaurav Sharma , Robert P. Loce+ , Steven revealed when the print is illuminated by suitably chosen illumi- nants. In its basic form, the technique illumina- tion. The paper is accompanied by a light-booth based demonstration of illuminant multiplexed

  4. 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.

  5. 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

  6. GCR as a source for Inner radiation belt of Saturn.

    NASA Astrophysics Data System (ADS)

    Kotova, A.; Roussos, E.; Krupp, N.; Dandouras, I. S.

    2014-12-01

    During the insertion orbit of Cassini in 2004 the Ion and Neutron Camera measured significant fluxes of the energetic neutral atoms (ENA) coming from the area between the D-ring and the Saturn's atmosphere, what brought up the idea of the possible existence of the innermost radiation belt in this narrow gap (1). There are two main sources of energetic charged particles for such inner radiation belt: the interaction of the Galactic Cosmic Rays (GCR) with the Saturn's atmosphere and rings, which due to CRAND process can produce the keV-MeV ions or electrons in the region, and the double charge exchange of the ENAs, coming from the middle magnetosphere, what can bring the keV ions to the region of our interest. Using the particles tracer, which was developed in our group, and GEANT4 software, we study in details those two processes. With a particle tracer we evaluate the GCR access to the Saturn atmosphere and rings. Simulation of the GCR trajectories allows to calculate the energy spectra of the arriving energetic particles, which is much more accurate, compare to the analytically predicted spectra using the Stoermer theory, since simulation includes effects of the ring shadow and non-dipolar processes in the magnetosphere. Using the GEANT4 software the penetration of the GCR through the matter of rings was simulated, and the production of secondaries particles was estimated. Finally, the motion of secondaries was simulated using the particles tracer, and evaluation of the energy spectrum of neutrons the decay of which leads to the production of final CRAND elements in the inner Saturnian radiation belts was done. We show that for inner radiation belt most energetic ions comes from GCR interaction with rings, it's penetration and from interaction of secondaries with Saturn's atmosphere. This simulation allows us to predict the fluxes of energetic ions and electrons, which particle detector MIMI/LEMMS onboard the Cassini can measure during the so-called "proximal" orbits in 2017, when the Cassini spacecraft will pass directly through this diverse and enigmatic region extremely close to the planet. References: (1) S. M. Krimigis et al., "Dynamics of Saturn's Magnetosphere from MIMI During Cassini's Orbital Insertion", Science 25 February 2005: 307 (5713), 1270-1273.

  7. 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.

  8. Engineering Event-Based Systems with Scopes

    Microsoft Academic Search

    Ludger Fiege; Mira Mezini; Gero Mühl; Alejandro P. Buchmann

    2002-01-01

    Event notification services enable loose coupling and they are therefore becoming an essential part of distributed systems' design. How- ever, the development of event services follows the early stages of pro- gramming language evolution, disregarding the need for efficient mech- anisms to structure event-based applications. In this paper, the well- known notion of scopes is introduced to event-based systems. We

  9. A New gcrR-Deficient Streptococcus mutans Mutant for Replacement Therapy of Dental Caries

    PubMed Central

    Pan, Wenting; Mao, Tiantian; Xu, Qing-an; Shao, Jin; Liu, Chang; Fan, Mingwen

    2013-01-01

    Background. gcrR gene acts as a negative regulator related to sucrose-dependent adherence in S. mutans. It is constructive to test the potential capacity of mutans with gcrR gene deficient in bacteria replacement therapy. Methods. In this study, we constructed the mutant by homologous recombination. The morphological characteristics of biofilms were analyzed by confocal laser scanning microscopy. S. mutans UA159 and the mutant MS-gcrR-def were inoculated, respectively, or together for competitive testing in vitro and in rat model. Results. Adhesion assay showed that the adhesion ability of the mutant increased relative to the wild type, especially in the early stage. MS-gcrR-def out-competed S. mutans UA159 in vitro biofilm, and correspondingly coinfection displayed significantly fewer caries in vivo. The former possessed both a lower level of acid production and a stronger colonization potential than S. mutans UA159. Conclusion. These findings demonstrate that MS-gcrR-def appears to be a good candidate for replacement therapy. PMID:24453853

  10. Asynchronous event-based binocular stereo matching.

    PubMed

    Rogister, Paul; Benosman, Ryad; Ieng, Sio-Hoi; Lichtsteiner, Patrick; Delbruck, Tobi

    2012-02-01

    We present a novel event-based stereo matching algorithm that exploits the asynchronous visual events from a pair of silicon retinas. Unlike conventional frame-based cameras, recent artificial retinas transmit their outputs as a continuous stream of asynchronous temporal events, in a manner similar to the output cells of the biological retina. Our algorithm uses the timing information carried by this representation in addressing the stereo-matching problem on moving objects. Using the high temporal resolution of the acquired data stream for the dynamic vision sensor, we show that matching on the timing of the visual events provides a new solution to the real-time computation of 3-D objects when combined with geometric constraints using the distance to the epipolar lines. The proposed algorithm is able to filter out incorrect matches and to accurately reconstruct the depth of moving objects despite the low spatial resolution of the sensor. This brief sets up the principles for further event-based vision processing and demonstrates the importance of dynamic information and spike timing in processing asynchronous streams of visual events. PMID:24808513

  11. Amorphous GCr15?Ta film formation by dynamic ion beam mixing and the film properties

    NASA Astrophysics Data System (ADS)

    Wang, Peilu; Liu, Zhong Yang; Jiang, Jingyun; Guo, Huachong

    1991-12-01

    Ta-rich surface alloys have been prepared directly on GCr15 bearing steel (corresponding to AISI52100 steel) substrates by the dynamic ion beam mixing technique. An amorphous alloy film of a given composition can be formed when the deposition temperature and the atom-ion arrival ratio are controlled appropriately. The microstructure and composition of such films were examined using TEM, EDX and XPS. Corrosion tests in H 2SO 4 and NaCl solutions, as well as friction and wear tests have shown that the amorphous GCr15?Ta alloy films formed by this technology have superior chemical and physical properties.

  12. CENDA: Camouflage Event Based Malicious Node Detection Architecture

    E-print Network

    Liu, Alex X.

    CENDA: Camouflage Event Based Malicious Node Detection Architecture Kanthakumar Pongaliur Li Xiao type of attack and lacks a unified architecture to identify multiple attack types. Camouflage Event Based Malicious Node Detection Architecture (CENDA) is a proactive architecture that uses camouflage

  13. p. 2 Time to say goodbye p. 3 GCR: President's report, Chairperson's report,

    E-print Network

    Wirosoetisno, Djoko

    Honours 2011 p. 5 Social Events: Eurovision, GCR BBQ, Summer Ball, Sports Formal p. 11 Off the Hill: MBA Academic: Café Politique, Ustinov Seminar p. 21 Alumni: A political life p. 23 Clubs & Societies p. 24. I was very pleased to have Penny at the table for many meetings where issues affecting postgraduate

  14. Amorphous GCr15Ta film formation by dynamic ion beam mixing and the film properties

    Microsoft Academic Search

    Peilu Wang; Zhong Yang Liu; Jingyun Jiang; Huachong Guo

    1991-01-01

    Ta-rich surface alloys have been prepared directly on GCr15 bearing steel (corresponding to AISI52100 steel) substrates by the dynamic ion beam mixing technique. An amorphous alloy film of a given composition can be formed when the deposition temperature and the atom-ion arrival ratio are controlled appropriately. The microstructure and composition of such films were examined using TEM, EDX and XPS.

  15. 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.

  16. Event-Based Approach to Modelling Dynamic Architecture

    E-print Network

    Paris-Sud XI, Université de

    Event-Based Approach to Modelling Dynamic Architecture: Application to Mobile Ad-Hoc Network.Attiogbe@univ-nantes.fr Abstract. We describe an event-based approach to specifiy systems with dynamically evolving architecture tools. Keywords: Specification, Verification, Dynamic Architecture, Event B. 1 Introduction Distributed

  17. Static Analysis for Event-Based XML Processing

    Microsoft Academic Search

    Anders Møller

    Event-based processing of XML data - as exemplified by the pop - ular SAX framework - is a powerful alternative to using W3C's DOM or similar tree-based APIs. The event-based approach is particularly superior when processing large XML documents in a streaming fashion with minimal memory consumption. This paper discusses challenges for creating program analy ses for SAX applications. In

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

    PubMed Central

    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. 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.

  20. 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?

  1. Secondary Cosmic Ray Particles due to GCR Interactions in the Earth's Atmosphere

    SciTech Connect

    Battistoni, G.; Garzelli, M. V.; Muraro, S.; Sala, P. R. [University of Milano, Department of Physics, and INFN, Milan (Italy); Cerutti, F.; Ferrari, A.; Roesler, S. [CERN, Geneva (Switzerland); Fasso, A. [SLAC, Stanford, CA (United States); Lantz, M. [Chalmers University, Department of Fundamental Physics, Goteborg (Sweden); Pinsky, L. S. [University of Houston, Department of Physics, Houston, TX (United States); Ranft, J. [Siegen University, Fachbereich 7-Physik, Siegen (Germany)

    2008-01-24

    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.

  2. Exploiting Interference Diversity for Event-Based Spectrum Sensing

    E-print Network

    Sahai, Anant

    Exploiting Interference Diversity for Event-Based Spectrum Sensing Anant Sahai presenting jointSpAN 2008 Chicago, IL Anant Sahai (UC Berkeley) Exploiting Interference Diversity 10/15/2008 1 / 15 #12;Motivation: recovering spectrum holes Anant Sahai (UC Berkeley) Exploiting Interference Diversity 10

  3. Assessment and Event Based Analysis of Dynamic Wireless Networks

    E-print Network

    Paris-Sud XI, Université de

    Assessment and Event Based Analysis of Dynamic Wireless Networks Denis Carvin1,2, Guillaume Kremer1 of mobile nodes in networks is significantly changing the way they are managed. Indeed, these wireless-estimation algorithm for wireless mobile networks. We then provide events' collection and distributed mining methods

  4. Event based indexing of broadcasted sports video by intermodal collaboration

    Microsoft Academic Search

    Noboru Babaguchi; Yoshihiko Kawai; Tadahiro Kitahashi

    2002-01-01

    In this paper, we propose event-based video indexing, which is a kind of indexing by its semantical contents. Because video data is composed of multimodal information streams such as visual, auditory, and textual [closed caption (CC)] streams, we introduce a strategy of intermodal collaboration, i.e., collaborative processing taking account of the semantical dependency between these streams. Its aim is to

  5. 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

  6. Training Team Problem Solving Skills: An Event-Based Approach.

    ERIC Educational Resources Information Center

    Oser, R. L.; Gualtieri, J. W.; Cannon-Bowers, J. A.; Salas, E.

    1999-01-01

    Discusses how to train teams in problem-solving skills. Topics include team training, the use of technology, instructional strategies, simulations and training, theoretical framework, and an event-based approach for training teams to perform in naturalistic environments. Contains 68 references. (Author/LRW)

  7. SLEDE: event-based specification of sensor network security protocols

    Microsoft Academic Search

    Youssef Hanna; Hridesh Rajan

    2006-01-01

    The semantic gap between specification and implementation languages for sensor networks security protocols impedes the specification and verification of the protocols. In this work, we present SLEDE, an event-based specification language and its verifying compiler that address this semantic gap. We demonstrate the features of SLEDE through an exam- ple specification of the µTesla, secure broadcast protocol for sensor networks.

  8. STEAM: event-based middleware for wireless ad hoc networks

    Microsoft Academic Search

    Rene Meier; Vinny Cahill

    2002-01-01

    With the widespread deployment and use of wireless data communications in the mobile computing domain the need for middleware that interconnects the components that comprise a mobile application in distributed and potentially heterogeneous environments arises. Middleware utilizing an event-based communication model is well suited to address the requirements of the mobile computing domain, as it requires a less tightly coupled

  9. STEAM: Event-Based Middleware for Wireless Ad Hoc Network

    Microsoft Academic Search

    René Meier; Vinny Cahill

    2002-01-01

    With the widespread deployment and use of wireless datacommunications in the mobile computing domain the needfor middleware that interconnects the components that comprisea mobile application in distributed and potentiallyheterogeneous environments arises. Middleware utilizingan event-based communication model is well suited to addressthe requirements of the mobile computing domain, asit requires a less tightly coupled communication relationshipbetween application components compared to ...

  10. 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.

  11. Event-based Simulation Model for Quantum Optics Experiments

    SciTech Connect

    De Raedt, H. [Department of Applied Physics, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, NL-9747 AG Groningen (Netherlands); Michielsen, K. [Institute for Advanced Simulation, Juelich Supercomputing Centre, Research Centre Juelich, D-52425 Juelich (Germany)

    2011-03-28

    We present a corpuscular simulation model of optical phenomena that does not require the knowledge of the solution of a wave equation of the whole system and reproduces the results of Maxwell's theory by generating detection events one-by-one. The event-based corpuscular model gives a unified description of multiple-beam fringes of a plane parallel plate and single-photon Mach-Zehnder interferometer, Wheeler's delayed choice, photon tunneling, quantum eraser, two-beam interference, double-slit, Einstein-Podolsky-Rosen-Bohm and Hanbury Brown-Twiss experiments. We also discuss the possibility to refute our corpuscular model.

  12. Event-Based Simulation of Quantum Physics Experiments

    NASA Astrophysics Data System (ADS)

    Michielsen, Kristel; de Raedt, Hans

    2015-10-01

    We review an event-based simulation approach which reproduces the statistical distributions of wave theory not by requiring the knowledge of the solution of the wave equation of the whole system but by generating detection events oneby- one according to an unknown distribution. We illustrate its applicability to various single photon and single neutron interferometry experiments and to two Bell-test experiments, a single-photon Einstein-Podolsky-Rosen experiment employing post-selection for photon pair identification and a single-neutron Bell test interferometry experiment with nearly 100% detection efficiency.

  13. 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.

  14. DNA Binding of the Cell Cycle Transcriptional Regulator GcrA Depends on N6-Adenosine Methylation in Caulobacter crescentus and Other Alphaproteobacteria

    PubMed Central

    Mohapatra, Saswat S.; Bompard, Coralie; Brilli, Matteo; Frandi, Antonio; Castric, Vincent; Villeret, Vincent; Viollier, Patrick H.; Biondi, Emanuele G.

    2013-01-01

    Several regulators are involved in the control of cell cycle progression in the bacterial model system Caulobacter crescentus, which divides asymmetrically into a vegetative G1-phase (swarmer) cell and a replicative S-phase (stalked) cell. Here we report a novel functional interaction between the enigmatic cell cycle regulator GcrA and the N6-adenosine methyltransferase CcrM, both highly conserved proteins among Alphaproteobacteria, that are activated early and at the end of S-phase, respectively. As no direct biochemical and regulatory relationship between GcrA and CcrM were known, we used a combination of ChIP (chromatin-immunoprecipitation), biochemical and biophysical experimentation, and genetics to show that GcrA is a dimeric DNA–binding protein that preferentially targets promoters harbouring CcrM methylation sites. After tracing CcrM-dependent N6-methyl-adenosine promoter marks at a genome-wide scale, we show that these marks recruit GcrA in vitro and in vivo. Moreover, we found that, in the presence of a methylated target, GcrA recruits the RNA polymerase to the promoter, consistent with its role in transcriptional activation. Since methylation-dependent DNA binding is also observed with GcrA orthologs from other Alphaproteobacteria, we conclude that GcrA is the founding member of a new and conserved class of transcriptional regulators that function as molecular effectors of a methylation-dependent (non-heritable) epigenetic switch that regulates gene expression during the cell cycle. PMID:23737758

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

    SciTech Connect

    Wright, Steven A.; Lipinski, Ronald J. [Sandia National Laboratories, PO Box 5800, Albuquerque New Mexico 87185 (United States)

    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)

  16. 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

  17. Event-based user classification in Weibo media.

    PubMed

    Guo, Liang; 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

  18. Database of Gene Co-Regulation (dGCR): A Web Tool for Analysing Patterns of Gene Co-regulation across Publicly Available Expression Data

    PubMed Central

    Williams, Gareth

    2015-01-01

    The database of Gene Co-Regulation (dGCR) is a web tool for the analysis of gene relationships based on correlated patterns of gene expression over publicly available transcriptional data. The motivation behind dGCR is that genes whose expression patterns correlate across many experiments tend to be co-regulated and hence share biological function. In addition to revealing functional connections between individual gene pairs, extended sets of co-regulated genes can also be assessed for enrichment of gene ontology classes and interaction pathways. This functionality provides an insight into the biological function of the query gene itself. The dGCR web tool extends the range of expression data curated by existing co-regulation databases and provides additional insights into gene function through the analysis of pathways, gene ontology classes and co-regulation modules. PMID:25628763

  19. 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).

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

    SciTech Connect

    NONE

    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.

  1. Local and nonlocal geometry of interplanetary coronal mass ejections: Galactic cosmic ray (GCR) short-period variations and magnetic field modeling

    Microsoft Academic Search

    J. J. Quenby; T. Mulligan; J. B. Blake; J. E. Mazur; D. Shaul

    2008-01-01

    Energetic galactic cosmic ray (GCR) particles, arriving within the solar system, are modulated by the overall interplanetary field carried in the solar wind. Localized disturbances related to solar activity cause further reduction in intensity, the largest being Forbush decreases in which fluxes can fall ?20% over a few days. Understanding Forbush decreases leads to a better understanding of the magnetic

  2. Nd:YAG Laser: GCR-150-10 These questions have been designed to ensure that the users of the laser system understand the

    E-print Network

    Turro, Claudia

    Nd:YAG Laser: GCR-150-10 These questions have been designed to ensure that the users of the laser system understand the underlying principles of laser operation, that the laser is not damaged in the manual, please ask the person responsible for the laser. These questions must be answered fully

  3. 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,…

  4. 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…

  5. 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,…

  6. 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…

  7. Flood!: An Event-Based Science Module. Student Edition. Stream Dynamics 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. 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,…

  9. Shaping Event-Based Haptic Transients Via an Improved Understanding of Real Contact Dynamics

    E-print Network

    Kuchenbecker, Katherine J.

    Shaping Event-Based Haptic Transients Via an Improved Understanding of Real Contact Dynamics realistic when a short-duration transient is added to the spring force at contact. But how should this event-based transient be shaped? To answer this question, we present a targeted user study on virtual surface realism

  10. Hurricane!: 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 hurricanes 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,…

  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. An Event-based Approach to Distributed Diagnosis of Continuous Systems

    E-print Network

    Daigle, Matthew

    engineering systems, and the advent of smart sensors and computing elements. This paper presents a novel event- namic fault signatures expressed as event-based fault models. We develop a distributed diagnoser design algorithm that uses these models for de- signing local event-based diagnosers based on global diagnosability

  13. 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,…

  14. 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…

  15. Issues in Testing Dependable Event-Based Systems at a Systems Integration Company

    Microsoft Academic Search

    Armin Beer; Matthias Heindl

    2007-01-01

    Testing of dependable event-based systems is very important to ensure that all requirements (including nonfunctional requirements such as reliability, availability, safety and security) are met and the relevant standards are considered. Siemens Program and Systems Engineering is a company that builds dependable event-based systems in multiple domains. A special unit at PSE, the Support Center Test, focuses on testing issues.

  16. 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…

  17. 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,…

  18. Event-Based Imaging with Active Illumination in Sensor Thiago Teixeira, Andreas G. Andreou

    E-print Network

    Teixeira, Thiago

    imager is employed at the sensor level, to convert light intensity at each pixel into pulse densityEvent-Based Imaging with Active Illumination in Sensor Networks Thiago Teixeira, Andreas G. Andreou a distributed imaging architecture with active illumination for sensor network applications. An event-based CMOS

  19. 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,…

  20. Patterns of gene expression and a transactivation function exhibited by the vGCR (ORF74) chemokine receptor protein of Kaposi's sarcoma-associated herpesvirus.

    PubMed

    Chiou, Chuang-Jiun; Poole, Lynn J; Kim, Peter S; Ciufo, Dolores M; Cannon, Jennifer S; ap Rhys, Colette M; Alcendor, Donald J; Zong, Jian-Chao; Ambinder, Richard F; Hayward, Gary S

    2002-04-01

    The ORF74 or vGCR gene encoded by Kaposi's sarcoma-associated herpesvirus (KSHV; also called human herpesvirus 8) has properties of a ligand-independent membrane receptor signaling protein with angiogenic properties that is predicted to play a key role in the biology of the virus. We have examined the expression of vGCR mRNA and protein in primary effusion lymphoma (PEL) cell lines, PEL and multicentric Castleman's disease (MCD) tumors, Kaposi's sarcoma lesions and infected endothelial cell cultures. The vGCR gene proved to be expressed in PEL cell lines as a large spliced bicistronic mRNA of 3.2 kb that also encompasses the upstream vOX2 (K14) gene. This mRNA species was induced strongly by phorbol ester (TPA) and sodium butyrate treatment in the BCBL-1 cell line, but only weakly in the HBL6 cell line, and was classified as a relatively late and low-abundance delayed early class lytic cycle gene product. A complex bipartite upstream lytic cycle promoter for this mRNA was nestled within the intron of the 5'-overlapping but oppositely oriented latent-state transcription unit for LANA1/vCYC-D/vFLIP and responded strongly to both TPA induction and cotransfection with the KSHV RNA transactivator protein (RTA or ORF50) in transient reporter gene assays. A vGCR protein product of 45 kDa that readily dimerized was detected by Western blotting and in vitro translation and was localized in a cytoplasmic and membrane pattern in DNA-transfected Vero and 293T cells or adenovirus vGCR-transduced dermal microvascular endothelial cells (DMVEC) as detected by indirect immunofluorescence assay (IFA) and immunohistochemistry with a specific rabbit anti-vGCR antibody. Similarly, a subfraction of KSHV-positive cultured PEL cells and of KSHV (JSC-1) persistently infected DMVEC cells displayed cytoplasmic vGCR protein expression, but only after TPA or spontaneous lytic cycle induction, respectively. The vGCR protein was also detectable by immunohistochemical staining in a small fraction (0.5 to 3%) of the cells in PEL and MCD tumor and nodular Kaposi's sarcoma lesion specimens that were apparently undergoing lytic cycle expression. These properties are difficult to reconcile with the vGCR protein's playing a direct role in spindle cell proliferation, transformation, or latency, but could be compatible with proposed contributions to angiogenesis via downstream paracrine effects. The ability of vGCR to transactivate expression of both several KSHV promoter-driven luciferase (LUC) reporter genes and an NFkappaB motif containing the chloramphenicol acetyltransferase (CAT) reporter gene may also suggest an unexpected regulatory role in viral gene expression. PMID:11884567

  1. A Categorical Semantics of Event-based Architectures Jos Luiz Fiadeiro1

    E-print Network

    Lopes, Antónia

    , PORTUGAL mal@di.fc.ul.pt Abstract. We propose a mathematical semantics for event-based architectures-level #12;­ 2 ­ design. The advantages of adopting such a style so early in the development process stem

  2. A Formal Approach to Event-Based Architectures Jos Luiz Fiadeiro1

    E-print Network

    Lopes, Antónia

    mal@di.fc.ul.pt Abstract. We develop a formal approach to event-based architectures that serves two. The advantages of adopting such a style so early in the development process stem from exactly the same properties

  3. Event Based Low Frequency Impedance Modeling using Well Logs and Seismic Attributes

    E-print Network

    Mosegaard, Klaus

    a broad spatial frequency response, the accuracy of the predicted low frequency response and therefore the porosity estimates as comparedEvent Based Low Frequency Impedance Modeling using Well Logs and Seismic Attributes Radmila

  4. Concepts and models for typing events for event-based systems

    Microsoft Academic Search

    Szabolcs Rozsnyai; Josef Schiefer; Alexander Schatten

    2007-01-01

    Event-based systems are increasingly gaining widespread attention for applications that require integration with loosely coupled and distributed systems for time-critical business solutions. In this paper, we show concepts and models for representing, structuring and typing events. We discuss existing event models in the field and introduce the event model of the event-based system SARI for illustrating various typing concepts. The

  5. A methodology for unit testing actors in proprietary discrete event based simulations

    Microsoft Academic Search

    Mark E. Coyne; Scott R. Graham; Kenneth M. Hopkinson; Stuart H. Kurkowski

    2008-01-01

    1 ABSTRACT This paper presents a dependency injection based, unit test- ing methodology for unit testing components, or actors, involved in discrete event based computer network simu- lation via an xUnit testing framework. The fundamental purpose of discrete event based computer network simulation is verification of networking protocols used in physical-not simulated-networks. Thus, use of rigorous unit testing and test

  6. In vitro Manganese-Dependent Cross-Talk between Streptococcus mutans VicK and GcrR: Implications for Overlapping Stress Response Pathways

    PubMed Central

    Downey, Jennifer S.; Mashburn-Warren, Lauren; Ayala, Eduardo A.; Senadheera, Dilani B.; Hendrickson, Whitney K.; McCall, Lathan W.; Sweet, Julie G.; Cvitkovitch, Dennis G.; Spatafora, Grace A.; Goodman, Steven D.

    2014-01-01

    Streptococcus mutans, a major acidogenic component of the dental plaque biofilm, has a key role in caries etiology. Previously, we demonstrated that the VicRK two-component signal transduction system modulates biofilm formation, oxidative stress and acid tolerance responses in S. mutans. Using in vitro phosphorylation assays, here we demonstrate for the first time, that in addition to activating its cognate response regulator protein, the sensor kinase, VicK can transphosphorylate a non-cognate stress regulatory response regulator, GcrR, in the presence of manganese. Manganese is an important micronutrient that has been previously correlated with caries incidence, and which serves as an effector of SloR-mediated metalloregulation in S. mutans. Our findings supporting regulatory effects of manganese on the VicRK, GcrR and SloR, and the cross-regulatory networks formed by these components are more complex than previously appreciated. Using DNaseI footprinting we observed overlapping DNA binding specificities for VicR and GcrR in native promoters, consistent with these proteins being part of the same transcriptional regulon. Our results also support a role for SloR as a positive regulator of the vicRK two component signaling system, since its transcription was drastically reduced in a SloR-deficient mutant. These findings demonstrate the regulatory complexities observed with the S. mutans manganese-dependent response, which involves cross-talk between non-cognate signal transduction systems (VicRK and GcrR) to modulate stress response pathways. PMID:25536343

  7. Friction and Wear Behavior of UltraHigh Molecular Weight Polyethylene Sliding Against GCr15 Steel and Electroless Ni–P Alloy Coating Under the Lubrication of Seawater

    Microsoft Academic Search

    Jianzhang Wang; Fengyuan Yan; Qunji Xue

    2009-01-01

    The friction and wear behavior of ultra-high molecular weight polyethylene (UHMWPE) sliding against GCr15 steel and electroless\\u000a Ni-P alloy coating under the lubrication of seawater was investigated and compared with that under dry sliding and lubrication\\u000a of pure water and 3.5 wt.% NaCl solution, respectively. It was found that under the lubrication of aqueous medium, the friction\\u000a and wear behavior of

  8. 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.

  9. Context-Awareness and Adaptation in Distributed Event-Based Systems

    E-print Network

    Waterloo, University of

    Context-Awareness and Adaptation in Distributed Event-Based Systems Eduardo S. Barrenechea, Paulo S of Waterloo Technical Report CS-2011-14 Abstract Context-aware and proactive technologies have been through events. Although there have been significant advances in distributed context-aware systems

  10. Lecture 11: Event-based control over wireless networks Lecture 11 Outline

    E-print Network

    Johansson, Karl Henrik

    The control uk for the optimal closed-loop system has a dual e ect. Event-based scheduler Ramesh et al Access with Collision Avoidance #12;4/25/13 9 Detailed model of CSMA/CA in IEEE 802: collision probability Idle state Backoff stage 1CCA Tx CCA Retransmission stage n Backof

  11. PrivateFlow: Decentralised Information Flow Control in Event Based Middleware (Demo)

    E-print Network

    Pietzuch, Peter

    be generally acceptable, in a privacy-aware health- care environment guarantees must exist that it will neverPrivateFlow: Decentralised Information Flow Control in Event Based Middleware (Demo) I the security of the whole platform. Aiming to minimize these problems, we propose a demon- stration of Private

  12. Low-Latency Event-Based Visual Odometry Andrea Censi Davide Scaramuzza

    E-print Network

    Low-Latency Event-Based Visual Odometry Andrea Censi Davide Scaramuzza Abstract-- The agility odometry methods are not applicable. This paper presents the first visual odometry system based on a DVS are automatically spatiotemporally calibrated from logs taken during normal operation. We design a visual odometry

  13. Qualitative Event-based Diagnosis with Possible Conflicts Applied to Spacecraft

    E-print Network

    Daigle, Matthew

    . In this scheme, fault isolation is achieved through analysis of the transients produced by faults, manifesting based on a qualitative event-based fault isolation framework augmented with model-based fault, fault isolation, and fault identification; whereas the other uses a set of minimal submodels computed

  14. Event-Based Haptics and Acceleration Matching: Portraying and Assessing the Realism of Contact

    E-print Network

    Kuchenbecker, Katherine J.

    - uated this haptic rendering paradigm by conducting a study in which users blindly rated the realism but not actively con- trolled. Most haptic algorithms attempt to re-create the expe- rience of hard contactEvent-Based Haptics and Acceleration Matching: Portraying and Assessing the Realism of Contact

  15. Event-based motion control for mobile sensor networks Zack Butler and Daniela Rus

    E-print Network

    Butler, Zack

    Event-based motion control for mobile sensor networks Zack Butler and Daniela Rus Dept. of Computer. In Sec. 2 we present two different control methods for sensors to converge on arbitrary distributions-driven control method, so that the sensors will follow the control law unless required to stop to ensure coverage

  16. Empirical study of Mandarin Chinese discourse analysis: an event-based approach

    Microsoft Academic Search

    Yuan-Kai Wang; Yi-Shiou Chen; Wen-Lian Hsu

    1998-01-01

    Discourse analysis plays an important role in natural language understanding. Mandarin Chinese discourse, which has many different properties compared with English discourse, is still far behind in the construction of a basic computational model. We propose an event model to elucidate anaphora and ellipsis in Mandarin Chinese. An event based approach (EBA) based on the model is designed to resolve

  17. Use of Unstructured Event-Based Reports for Global Infectious Disease Surveillance

    PubMed Central

    Blench, Michael; Tolentino, Herman; Freifeld, Clark C.; Mandl, Kenneth D.; Mawudeku, Abla; Eysenbach, Gunther; Brownstein, John S.

    2009-01-01

    Free or low-cost sources of unstructured information, such as Internet news and online discussion sites, provide detailed local and near real-time data on disease outbreaks, even in countries that lack traditional public health surveillance. To improve public health surveillance and, ultimately, interventions, we examined 3 primary systems that process event-based outbreak information: Global Public Health Intelligence Network, HealthMap, and EpiSPIDER. Despite similarities among them, these systems are highly complementary because they monitor different data types, rely on varying levels of automation and human analysis, and distribute distinct information. Future development should focus on linking these systems more closely to public health practitioners in the field and establishing collaborative networks for alert verification and dissemination. Such development would further establish event-based monitoring as an invaluable public health resource that provides critical context and an alternative to traditional indicator-based outbreak reporting. PMID:19402953

  18. Prediction of solar proton events based on solar radio emissions. Environmental research papers

    Microsoft Academic Search

    OBrien

    1970-01-01

    The short-term prediction of solar proton events based on a distinct U-shaped radio burst signature is verified. The prediction technique uses peak flux density values of discrete frequency solar radio burst observations in the 100 to 10,000 MHz region. The criteria are applied to all major proton events from 1952 to 1969 and afford almost total success in predicting near-earth

  19. Event-based Transmission Line Matrix Method for Simulating Site-Specific Multipath Propagation Characteristics

    SciTech Connect

    Kuruganti, Phani Teja [ORNL] [ORNL; Nutaro, James J [ORNL] [ORNL; Djouadi, Seddik M [ORNL] [ORNL

    2012-01-01

    Accurate radio channel modeling is essential for deploying advanced wireless sensors in harsh industrial and urban environments. Site-specific propagation modeling tools are required to understand the channel parameters with in these environments. Multipath delay spread determines the frequency-selective fading characteristics of the channel. This paper describes a novel computationally inexpensive technique to determine multipath delay spread. Event-based transmission line matrix-based method is used to simulate the channel.

  20. The influence of event-based sampling techniques on data transmission and control performance

    Microsoft Academic Search

    A. Pawlowski; J. L. Guzman; F. Rodriguez; M. Berenguel; J. Sanchez; S. Dormido

    2009-01-01

    Event-based systems are becoming increasingly commonplace, particularly for distributed real-time sensing and control. Furthermore, remote monitoring and control through data-communication networks are very popular for process supervision and control. The usage of networks provide many well-known benefits, but it also presents some limitations in the amount of transmitted data. This fact is especially visible in Wireless Sensor Network (WSN), where

  1. Investigating the output monitoring component of event-based prospective memory performance

    Microsoft Academic Search

    Richard L. Marsh; Jason L. Hicks; Thomas W. Hancock; Kirk Munsayac

    2002-01-01

    The goal of this study was to augment the standard event-based prospective memory paradigm with an output monitoring component.\\u000a That component involves memory for past actions and, in the context of prospective memory, is largely responsible for repetition\\u000a and omission errors. The modified paradigm also provides an index of what people believe to be true concerning their past\\u000a prospective memory

  2. 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-w?(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 w?(1) toward positive values as frequency of movements increase. PMID:25837726

  3. 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.

  4. University of Oregon | Public and Government Affairs | 541-346-5020 | gcr@uoregon.edu | 12/12/12 | p.1 A Public Institutional Board for the University of Oregon

    E-print Network

    Oregon, University of

    to advance the state's 40-40-20 educational goals, the UO needs access to capital. A public institutional tuition. As a public university, the UO is committed to providing access for Oregon residents. TuitionUniversity of Oregon | Public and Government Affairs | 541-346-5020 | gcr@uoregon.edu | 12

  5. GCR and SPE organ doses in deep space with different shielding: Monte Carlo simulations based on the FLUKA code coupled to anthropomorphic phantoms

    NASA Astrophysics Data System (ADS)

    Ballarini, F.; Battistoni, G.; Cerutti, F.; Fassò, A.; Ferrari, A.; Gadioli, E.; Garzelli, M. V.; Mairani, A.; Ottolenghi, A.; Paretzke, H. G.; Parini, V.; Pelliccioni, M.; Pinsky, L.; Sala, P. R.; Scannicchio, D.; Trovati, S.; Zankl, M.

    Astronauts' exposure to space radiation is of high concern for long-term missions, especially for those in deep space such as possible travels to Mars. In these cases shielding optimization is a crucial issue, and simulations based on radiation transport codes and anthropomorphic model phantoms can be of great help. In this work the FLUKA Monte Carlo code was coupled with two anthropomorphic phantoms (a mathematical model and a "voxel" model) to calculate organ-averaged dose, dose equivalent and "biological dose" in the various tissues and organs following exposure to the August 1972 Solar Particle Event and to Galactic Cosmic Rays under different shielding conditions. The "biological dose" was characterized by the average number of induced "Complex Lesions" (CLs) per cell in a given organ or tissue, where CLs are clustered DNA breaks which can play an important role in chromosome aberration induction. Separate calculation of the contributions from secondary hadrons - in particular neutrons - with respect to primary particles allowed us to quantify the role played by nuclear interactions occurring in the shield and in the human body. Specifically for GCR, the contributions from the different components of the incident primary spectra were calculated separately as well. As expected, the SPE doses showed a dramatic decrease with increasing Al shielding. Furthermore, for SPEs internal organs received much lower doses with respect to skin, and nuclear interactions were found to be of minor importance. A 10 g/cm 2 Al storm shelter turned out to be sufficient to respect the NCRP limits for 30-days LEO missions in case of a SPE similar to the August 1972 event. In contrast with SPEs, GCR absorbed doses remained roughly constant with increasing Al shielding. The organ-averaged dose equivalent and biological dose showed a (slight) decrease starting from a shield thickness of 2 g/cm 2, probably due the lower LET of projectile fragments.

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

    SciTech Connect

    Berry, Lee A [ORNL; Elwasif, Wael R [ORNL; Reynolds-Barredo, J. [University of Alaska; University Carlos III de Madrid; Samaddar, D. [ITER Organization, Saint Paul Lez Durance, France; Sanchez, R. [Universidad Carlos III, Madrid, Spain; Newman, David E [University of Alaska; Chen, J. [Princeton Plasma Physics Laboratory (PPPL)

    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.

  7. 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

  8. Event-based knowledge extraction from free-text descriptions for art images by using semantic role labeling approaches

    Microsoft Academic Search

    Chia-hung Lin; Chia-wei Yen; Jen-shin Hong; Samuel Cruz-lara

    2008-01-01

    Purpose – The purpose of this paper is to show how previous studies have demonstrated that non-professional users prefer using event-based conceptual descriptions, such as “a woman wearing a hat”, to describe and search images. In many art image archives, these conceptual descriptions are manually annotated in free-text fields. This study aims to explore technologies to automate event-based knowledge extractions

  9. Comparing Older and Younger Adults in an Event-Based Prospective Memory Paradigm Containing an Output Monitoring Component

    Microsoft Academic Search

    Richard L. Marsh; Jason L. Hicks; Gabriel I. Cook; Christopher B. Mayhorn

    2007-01-01

    Two experiments with younger and older adults were conducted to investigate the output-monitoring component of event-based prospective memory. In the standard form of the task, participants must remember to press a key when a certain class of items is encountered. To evaluate output monitoring, event-based cues were repeated and participants were asked to press a different key if they could

  10. 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.

  11. Event-based parareal: A data-flow based implementation of parareal

    NASA Astrophysics Data System (ADS)

    Berry, L. A.; Elwasif, W.; Reynolds-Barredo, J. M.; Samaddar, D.; Sanchez, R.; Newman, D. E.

    2012-07-01

    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. Very 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. As a result, tasks for one iteration do not wait for the previous iteration to complete, but are started when the needed data are available. For given convergence properties, the event-based approach relaxes the speed requirements on the coarse solver by a factor of ˜K, where K 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. In addition, the framework used for this implementation executes a task when the data dependencies are satisfied and computational resources are available. This leads to improved computational efficiency over previous approaches that pipeline or schedule groups of tasks to a particular processor or group of processors.

  12. 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

  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. 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

  15. 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

  16. Event based Kalman filter observer for rotary high speed on/off valve Meng Wang, Perry Y. Li

    E-print Network

    Li, Perry Y.

    Event based Kalman filter observer for rotary high speed on/off valve Meng Wang, Perry Y. Li ERC, pli}@me.umn.edu Abstract-- A novel hydraulic rotary self-spinning high speed on/off valve is being- width-modulation (PWM). The valve is designed to operate at a spool frequency of 20Hz to 40Hz. A coarse

  17. Event-Based Control for Embedded and Networked System Application to a Mini Quadrotor Helicopter using Motion Capture

    E-print Network

    Paris-Sud XI, Université de

    Event-Based Control for Embedded and Networked System Application to a Mini Quadrotor Helicopter for controlling the position of a real-time mini quadrotor helicopter using a motion capture system with deported of the controlled system varies). Typical event-detection mechanisms are functions on the variation of the state (or

  18. Reducing Inter-Cell Handover Events based on Cell ID Information in Multi-hop Relay Systems

    E-print Network

    Kim, Yong Jung

    Reducing Inter-Cell Handover Events based on Cell ID Information in Multi-hop Relay Systems Ji Hyun is needed for Mobile Multi-hop Relay (MMR) systems. This article proposes a novel handover method. Therefore, some novel cellular network architectures are being studied. Multi-hop relaying concept is a key

  19. Submission to International Journal of Control, Automation, and Systems 1 Event-Based Control of the Inverted Pendulum

    E-print Network

    Boyer, Edmond

    of the Inverted Pendulum: Swing up and Stabilization Sylvain Durand, J. Fermi Guerrero-Castellanos, Nicolas to control a nonlinear and unstable system, that is the inverted pendulum. We are first interested on the stabilization of the pendulum near its inverted position and propose an event-based control approach

  20. Using Event Based Data to Assess Vehicle Pedestrian Crash Risk in the Absence of All-Red

    E-print Network

    Minnesota, University of

    Using Event Based Data to Assess Vehicle Pedestrian Crash Risk in the Absence of All-Red Phase decision making at a signalized intersection? Ø How effective is the signal timing (particularly "All-Red lane.) #12;4 4 ØData analyzed between 10:30 am to 5 pm. ØTypical Yellow duration = 3 secs, All-Red

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. NIST GCR 02841 Between Invention

    E-print Network

    Magee, Joseph W.

    _branscomb@harvard.edu Philip E. Auerswald Assistant Director, Science, Technology, and Public Policy Program Kennedy School . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 1. The economic nature and value of technology-based innovations . . . . . . . . 27 A. Toward a project-level definition of technology-based innovation . . . . . 27 B. Applied research? Seed investment

  6. 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 ?s. 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

  7. Event-based knowledge elicitation of operating room management decision-making using scenarios adapted from information systems data

    PubMed Central

    2011-01-01

    Background No systematic process has previously been described for a needs assessment that identifies the operating room (OR) management decisions made by the anesthesiologists and nurse managers at a facility that do not maximize the efficiency of use of OR time. We evaluated whether event-based knowledge elicitation can be used practically for rapid assessment of OR management decision-making at facilities, whether scenarios can be adapted automatically from information systems data, and the usefulness of the approach. Methods A process of event-based knowledge elicitation was developed to assess OR management decision-making that may reduce the efficiency of use of OR time. Hypothetical scenarios addressing every OR management decision influencing OR efficiency were created from published examples. Scenarios are adapted, so that cues about conditions are accurate and appropriate for each facility (e.g., if OR 1 is used as an example in a scenario, the listed procedure is a type of procedure performed at the facility in OR 1). Adaptation is performed automatically using the facility's OR information system or anesthesia information management system (AIMS) data for most scenarios (43 of 45). Performing the needs assessment takes approximately 1 hour of local managers' time while they decide if their decisions are consistent with the described scenarios. A table of contents of the indexed scenarios is created automatically, providing a simple version of problem solving using case-based reasoning. For example, a new OR manager wanting to know the best way to decide whether to move a case can look in the chapter on "Moving Cases on the Day of Surgery" to find a scenario that describes the situation being encountered. Results Scenarios have been adapted and used at 22 hospitals. Few changes in decisions were needed to increase the efficiency of use of OR time. The few changes were heterogeneous among hospitals, showing the usefulness of individualized assessments. Conclusions Our technical advance is the development and use of automated event-based knowledge elicitation to identify suboptimal OR management decisions that decrease the efficiency of use of OR time. The adapted scenarios can be used in future decision-making. PMID:21214905

  8. 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…

  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. Is the isotopic composition of event based precipitation driven by moisture source or synoptic scale weather in the Sydney Basin, Australia?

    NASA Astrophysics Data System (ADS)

    Crawford, Jagoda; Hughes, Catherine E.; Parkes, Stephen D.

    2013-12-01

    Event based rainfall samples from Mt Werong were analysed for isotopic composition.?18O was more enriched when the moisture was sourced over land compared to the ocean.?18O in rainfall from East Coast Lows was more depleted than other synoptic weather systems.Winter and summer depleted events were associated with higher precipitation amount.

  11. Invited paper on Special Issue of Machine Vision and Applications Journal IBM Smart Surveillance System (S3): Event Based Video Surveillance

    E-print Network

    Senior, Andrew

    System (S3): Event Based Video Surveillance System with an Open and Extensible Framework Ying-li Tian. Introduction Smart Video Surveillance is the use of computer vision and pattern recognition technologies applications. Video analysis and video surveillance are active areas of research. The key technologies

  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. Tracing time in the ocean: a brief review of chronological constraints (60-8 kyr) on North Atlantic marine event-based stratigraphies

    NASA Astrophysics Data System (ADS)

    Austin, William E. N.; Hibbert, Fiona D.

    2012-03-01

    Well-resolved event-based stratigraphies in marine sediments spanning a significant portion of the last glacial period (60-8 kyr) provide a unique opportunity for time-stratigraphic correlation in the North Atlantic region. Here, we review the current methods available to chronologically constrain these event-based stratigraphies, highlighting, in particular, the value of tephrochronology as an independent tool to validate correlations between records. While the INTIMATE protocols (Lowe et al., 2008; Blockley et al., 2011) are equally applicable to marine and terrestrial records, spatially and temporally variable marine radiocarbon reservoir age effects (MREs) provide a challenge to using marine radiocarbon in the former as an independent chronostratigraphic tool. Despite the inherent uncertainties associated with 'tuning', we conclude that the mid-points of the common abrupt warming transitions associated with the well-defined, millennial-scale climate oscillations (the Dansgaard-Oeschger (D/O) cycles) observed in the oxygen isotopes of the Greenland ice cores and North Atlantic sea surface temperature (SST) records currently provide the most robust correlation tie-points from which to derive age control. In this invited INTIMATE special issue article we propose a new protocol for establishing marine event-based chronostratigraphies in the North Atlantic region and focus on areas of chronological potential in palaeoceanographic research.

  14. Simulation of the interaction of GCR protons with meteoroids: On the production of radionuclides in thick gabbro and iron targets irradiated isotropically with 1.6 GeV protons

    NASA Astrophysics Data System (ADS)

    Leya, I.; Lange, H.-J.; Lüpke, M.; Neupert, U.; Daunke, R.; Fanenbruck, O.; Michel, R.; Rösel, R.; Meltzow, B.; Schiekel, T.; Sudbrock, F.; Herpers, U.; Filges, D.; Bonani, G.; Dittrich-Hannen, B.; Suter, M.; Kubik, P. W.; Synal, H.-A.

    2000-03-01

    Thick spherical targets made of gabbro (R = 25 cm) and of steel (R = 10 cm) were irradiated isotropically with 1.6 GeV protons at the Saturne synchrotron at Laboratoire National Saturne (LNS) / CEN Saclay in order to simulate the interaction in space of galactic cosmic ray (GCR) protons with stony and iron meteoroids. Proton fluences of 1.32 ( 1014 cm-2 and 2.45 ( 1014 cm-2 were received by the gabbro and iron sphere, respectively, which corresponds to cosmic ray exposure ages of about 1.6 Ma and 3.0 Ma. Both artificial meteoroids contained large numbers of high-purity target foils of up to 28 elements at different depths. In these individual target foils, elementary production rates of radionuclides and rare gas isotopes were measured by X- and (-spectrometry, by low-level counting, accelerator mass spectrometry (AMS) and by conventional rare gas mass spectrometry. Also samples of the gabbro itself were analyzed. Up to now, for each of the experiments about 500 target-product combinations were investigated of which the results for radionuclides are presented here. The experimental production rates show a wide range of depth profiles reflecting the differences between low-, medium- and high-energy products. The influence of the stony and iron matrices on the production of secondary particles and on particle transport, in general, and consequently on the production rates is clearly exhibited by the phenomenology of the production rates as well as by a detailed theoretical analysis. Theoretical production rates were calculated in an a priori way by folding depth-dependent spectra of primary and secondary protons and secondary neutrons calculated by Monte Carlo techniques with the excitation functions of the underlying nuclear reactions. Discrepancies of up to a factor of 2 between the experimental and a priori calculated depth profiles are attributed to the poor quality of the mostly theoretical neutron excitation functions. Improved neutron excitation functions were obtained by least-squares deconvolution techniques from experimental thick-target production rates of up to five thick-target experiments in which isotropic irradiations were performed. A posteriori calculations using the adjusted neutron cross sections describe the measured depth profiles of all these simulation experiments within 9 %. The thus validated model calculations provide a basis for reliable physical model calculations of the production rates of cosmogenic nuclides in stony and iron meteorites as well as in lunar samples and terrestrial materials.

  15. 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

  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. The Semantic Relatedness of Cue-Intention Pairings Influences Event-Based Prospective Memory Failures in Older Adults with HIV Infection

    PubMed Central

    Woods, Steven Paul; Dawson, Matthew S.; Weber, Erica; Grant, Igor

    2009-01-01

    HIV infection and aging are each independently associated with prospective memory (ProM) impairment, which increases the risk of poor functional outcomes, including medication adherence. The incidence and prevalence of HIV infection among older adults has increased in recent years, thereby raising questions about the combined effects of these risk factors on ProM. In the present study, 118 participants were classified into four groups on the basis of HIV serostatus and age (i.e., ? 40 years and ? 50 years). Results showed significant additive effects of HIV and aging on event-based ProM, with the greatest deficits evident in the older HIV+ group, even after controlling for other demographic factors and potential medical, and psychiatric confounds. Event-based ProM impairment was particularly apparent in the older HIV+ group on trials for which the retrieval cue and intention were not semantically related. Worse performance on the semantically unrelated cue-intention trials was associated with executive dysfunction, older age, and histories of immunocompromise in the older HIV+ cohort. These data suggest that older HIV-infected adults are significantly less proficient at engaging the strategic encoding and retrieval processes required to a execute a future intention when the cue is unrelated to the intended action, perhaps secondary to greater neuropathological burden in the prefrontostriatal systems critical to optimal ProM functioning. PMID:19763997

  18. 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.

  19. Limited correlation between conventional pathologist and automatic computer-assisted quantification of hepatic steatosis due to difference between event-based and surface-based analysis.

    PubMed

    Deng, Meihong; Dahmen, Uta; Sun, Jian; Huang, Hai; Sehestedt, Christian; Homeyer, Andre; Schenk, Andrea; Dirsch, Olaf

    2014-07-01

    Computer-assisted automatic quantification (CAQ) was developed as an alternative method for the diagnosis of hepatic steatosis in order to compensate for observer-dependent bias. Here, we aim to demonstrate that CAQ can provide an accurate and precise result in analysis of fatty content, but that it is inappropriate to validate CAQ by comparison with conventional pathologist estimation (PE). Male rats were fed with a methionine-choline-deficient plus high-fat diet for three days, one week, or two weeks to induce mild, moderate, or severe steatosis. Samples were collected from all liver lobes. Severity of hepatic steatosis was assessed by an experienced pathologist who estimated the percentage of hepatocytes containing lipid droplets. Fatty content was quantified by PE, CAQ, and biochemical analysis (BA). CAQ, PE, and BA can correctly reflect severe fatty change. However, in the case of mild and moderate steatosis, PE could not reflect the true fatty content ( r between PE and BA was <0). The result of CAQ correlated well with that of BA among the various degrees of severity of hepatic steatosis. In conclusion, due to a difference between event-based and surface-based analysis, it is inappropriate to validate the CAQ of hepatic steatosis by comparison with PE. PMID:24235313

  20. 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

  1. Change of address is an event-based SEVIS reporting requirement. Address verification is also required for initial SEVIS registration and periodic 30-day status reporting in the beginning of each fall

    E-print Network

    Fernandez, Eduardo

    Change of address is an event-based SEVIS reporting requirement. Address verification is also visa classification must report a change of address to the school within 10 days from occurrence. ISSS has 21 days from receiving the information to report the change of address to SEVIS. ISSS will use

  2. 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].

  3. p. 2--GCR Executive columns p.4--Arrivals and Returns

    E-print Network

    Wirosoetisno, Djoko

    Walking to work today in my new winter coat and hat it's difficult to remember that only a few, short everyone involved in the ten days of Induction `Week'. It wouldn't have been possible without the dozens, representation and welfare support that can benefit all students in Ustinov. Chairperson's Report Iain Wallace

  4. Modeling of GCR Environment Variations and Interpretation for Human Explorations

    NASA Astrophysics Data System (ADS)

    Saganti, Premkumar

    We currently have wealth of data with several short duration Space Shuttle (STS) flights to the low earth orbit (LEO) and long duration International Space Station (ISS) expeditions as well as Shuttle-Mir missions over the past few solar cycles. Assessment of such radiation risk is very important particularly for the anticipated long-term and deep-space human explorations. Recently, we have developed a database of first 500 + human explorers and their space travel logs from space exploration missions during the past four decades. Many have traveled into space for only few days while others have been in space for several months. We present the time-line distribution of the space travelers log along with the time correlated radiation en-vironment changes in to aid in the radiation risk assessment for human explorations. These model calculated results and assessment of radiation exposure helps in our understanding of radiation risk and biological consequences.

  5. Stochastic Event-Based Control and Estimation

    E-print Network

    -concavity like inverse covariance in a Kalman filter. A recursive state estimator is developed for systems with both stochastic and set-bounded process and measurement noise terms. A time-varying linear filter gain control. Example problems for first-order plants are investigated, for a single control loop

  6. Event based Control for Distributed Systemsy

    E-print Network

    Johansson, Karl Henrik

    ;A history of controlA history of control Wireless control [Baillieul & Antsaklis, 2007] Today Controller Ore Waste #12;SAP OPC-UA ClientWireless control demonstration integrating Web services Siemans Wireless control demonstration integrating ABB Siemens SAP systems 17 18 Jun 2008 Gateway: OPC-UA Server

  7. 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.

  8. Process Mining Discovering Workflow Models from Event-Based Data

    E-print Network

    van der Aalst, Wil

    ordered. Any information system using transactional systems such as ERP, CRM, or workflow management 2473857/2290 Abstract Contemporary workflow management systems are driven by explicit process models, i the actual workflow processes and the processes as perceived by the management. Therefore, we propose

  9. INVITED SESSION NUMBER: 157 Event-Based Feedback Control

    E-print Network

    Moehlis, Jeff

    successful in alleviating the symptoms of a variety of diseases including neuromotor disorders, obsessive in the tissue). In the limit of weak coupling, we envision a set of such controllers driving a population

  10. Balboa: A Framework for Event-Based Process Data Analysis

    Microsoft Academic Search

    Jonathan E. Cook; Alexander L. Wolf

    1998-01-01

    Software process research has suer ed from a lack of focussed data analysis techniques and tools. Part of the problem is the ad hoc and heterogeneous nature of the data, as well as the methods of collecting those data. While collection methods must be specic to their data source, analysis tools should be shielded from specic data formats and idiosyncrasies.

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

    PubMed

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

    2015-01-01

    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 ?m 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, ? 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. © 2015 International Society for Advancement of Cytometry. PMID:25572722

  12. Event-based data dissemination control in healthcare

    E-print Network

    Cambridge, University of

    in healthcare towards preventative care. This shift involves using technology to assist in care provision outside tra- ditional care institutions -- for instance, in a patient's home. To support such an environment, care providers require notification of incidents as they occur. However, health information

  13. Event-based Simulation Model for Quantum Optics Experiments

    E-print Network

    of the whole system and reproduces the results of Maxwell's theory by generating detection events one-separated directions, allowing for the cascade emission to be detected using a time-coincidence technique [5]. In Fig level cascade process: Only if detector D and D0, D1 or both fire, a cascade emission event occurred

  14. Event-based systems: opportunities and challenges at exascale

    Microsoft Academic Search

    Greg Eisenhauer; Matthew Wolf; Hasan Abbasi; Karsten Schwan

    2009-01-01

    Streaming data models have been shown to be useful in many applications requiring high-performance data exchange. Application-level overlay networks are a natural way to realize these applications' data flows and their internal computations, but existing middleware is not designed to scale to the data rates and low overhead computations necessary for the high performance domain. This paper describes EVPath, a

  15. Distributed Event-Based Control Strategies for Interconnected Linear

    E-print Network

    Johansson, Karl Henrik

    (NCS) for allowing a more efficient usage of the limited bandwidth of the network [2]-[6]. Large. Hence, there is a natural interest in applying event-triggering to decentralized NCS. There are some information. In the most common implementations, an event is triggered when the error of the system exceeds

  16. Event-Based Blackboard Architecture for Multi-Agent Systems

    Microsoft Academic Search

    Jing Dong; Shanguo Chen; Jun-jang Jeng

    2005-01-01

    Developing large multi-agent systems is a complex task involving the processes of the requirement, architecture, design and implementation of these systems. In particular, the architectural design is critical to cope with the increasing size and complexity of these systems. The multi-agent system that accesses a central repository is typically based on the Blackboard architectural pattern. However, the control strategies of

  17. 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

  18. An Event-Based Digital Forensic Investigation Framework

    Microsoft Academic Search

    Brian D. Carrier; Eugene H. Spafford

    2004-01-01

    In this paper, we present a framework for digital forensics that includes an investigation process model based on physical crime scene procedures. In this model, each digital device is considered a digital crime scene, which is included in the physical crime scene where it is located. The investigation includes the preservation of the system, the search for digital evidence, and

  19. 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

  20. Deterministic event-based simulation of quantum phenomena

    NASA Astrophysics Data System (ADS)

    De Raedt, K.; De Raedt, H.; Michielsen, K.

    2005-09-01

    We propose and analyse simple deterministic algorithms that can be used to construct machines that have primitive learning capabilities. We demonstrate that locally connected networks of these machines can be used to perform blind classification on an event-by-event basis, without storing the information of the individual events. We also demonstrate that properly designed networks of these machines exhibit behavior that is usually only attributed to quantum systems. We present networks that simulate quantum interference on an event-by-event basis. In particular we show that by using simple geometry and the learning capabilities of the machines it is possible to simulate single-photon interference in a Mach-Zehnder interferometer. The interference pattern generated by the network of deterministic learning machines is in perfect agreement with the quantum theoretical result for the single-photon Mach-Zehnder interferometer. To illustrate that networks of these machines are indeed capable of simulating quantum interference we simulate, event-by-event, a setup involving two chained Mach-Zehnder interferometers, and demonstrate that also in this case the simulation results agree with quantum theory.

  1. Deterministic event-based simulation of quantum phenomena

    Microsoft Academic Search

    K. de Raedt; H. de Raedt; K. Michielsen

    2005-01-01

    We propose and analyse simple deterministic algorithms that can be used to construct machines that have primitive learning capabilities. We demonstrate that locally connected networks of these machines can be used to perform blind classification on an event-by-event basis, without storing the information of the individual events. We also demonstrate that properly designed networks of these machines exhibit behavior that

  2. Deterministic event-based simulation of quantum interference

    Microsoft Academic Search

    K. De Raedt; H. De Raedt; K. Michielsen

    2004-01-01

    We propose and analyse simple deterministic algorithms that can be used to\\u000aconstruct machines that have primitive learning capabilities. We demonstrate\\u000athat locally connected networks of these machines can be used to perform blind\\u000aclassification on an event-by-event basis, without storing the information of\\u000athe individual events. We also demonstrate that properly designed networks of\\u000athese machines exhibit behavior that

  3. Dynamic Event-Based Access Control as Term Rewriting

    E-print Network

    Fernández, Maribel

    . Despite the widespread adoption of Role-based Access Con- trol (RBAC) models, new access control models are required for new applications for which RBAC may not be especially well suited and for which implementations of RBAC do not enable properties of access con- trol policies to be adequately defined and proven

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

    Microsoft Academic Search

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

    2010-01-01

    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

  5. Simulation of performance of centrifugal circulators with vaneless diffuser for GCR applications

    Microsoft Academic Search

    N. Tauveron; I. Dor

    2010-01-01

    In the frame of the international forum GenIV, CEA has selected various innovative concepts of gas-cooled nuclear reactor. Thermal hydraulic performances are a key issue for the design. For transient conditions and decay heat removal situations, the thermal hydraulic performance must remain as high as possible. In this context, all the transient situations, the incidental and accidental scenarii must be

  6. "The GCR Collection: from Alaska to Antarctica and from Martinique to Macquarie Ridge"

    E-print Network

    Layer 3 A B 0 Depth (km) Seismic wave velocity (km/s) A Basalt Diabase Gabbro Peridotite Seismic models Diabase Gabbro Peridotite #12;#12;Peridotite, Gabbro, and Diabase/Layer 2b Cores from DSDP, ODP, IODP

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

    SciTech Connect

    NONE

    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.

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

    SciTech Connect

    NONE

    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.

  9. Role of GCR positive and negative particles in charging the LISA-PF test masses in 2015

    NASA Astrophysics Data System (ADS)

    Grimani, C.; Fabi, M.; Lobo, A. J.; Mateos, I.; Telloni, D.

    2015-05-01

    The LISA Pathfinder (LISA-PF) mission launch is scheduled during the second half of 2015. Galactic and solar ions with energies larger than 100 MeV/n and electrons above 10 MeV penetrate the spacecraft material and charge the gold-platinum test masses. This charging process generates spurious forces that, in some cases, may mimic the effects of genuine gravitational wave signals. A study of the test-mass charging due to galactic cosmic rays (GCRs) down to 1% in composition is reported here. The reliability of the results of this work is mainly limited by our capability to predict the energy spectra of GCRs in 2015. To this purpose, our model is applied to the expected PAMELA experiment proton data for the period January- March 2014 characterized by a positive polarity period and a level of solar modulation similar to those expected at the time of LISA-PF. The PAMELA observations will be available in the next few months. The comparison between our projections and measurements will provide valuable clues on the test-mass charging estimate uncertainty.

  10. 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.

  11. Some implications of an event-based definition of exposure to the risk of road accident.

    PubMed

    Elvik, Rune

    2015-03-01

    This paper proposes a new definition of exposure to the risk of road accident as any event, limited in space and time, representing a potential for an accident to occur by bringing road users close to each other in time or space of by requiring a road user to take action to avoid leaving the roadway. A typology of events representing a potential for an accident is proposed. Each event can be interpreted as a trial as defined in probability theory. Risk is the proportion of events that result in an accident. Defining exposure as events demanding the attention of road users implies that road users will learn from repeated exposure to these events, which in turn implies that there will normally be a negative relationship between exposure and risk. Four hypotheses regarding the relationship between exposure and risk are proposed. Preliminary tests support these hypotheses. Advantages and disadvantages of defining exposure as specific events are discussed. It is argued that developments in vehicle technology are likely to make events both observable and countable, thus ensuring that exposure is an operational concept. PMID:25560900

  12. A THREADED EVENT-BASED SIMULATION APPROACH TO ANALYZING THE INTELLI-

    E-print Network

    Ritter, Frank

    In intelligence analysis, data can be incomplete, ambiguous, and of large volume. Also, the data may help with intelligence analysis of WMD attacks against critical infrastructure. Keywords: Intelligence #12;2 Figure 1. Workflow of the intelligence analysis paper is on analyzing the intelligence on WMD

  13. Rain Characteristics and Large-Scale Environment Associated with Extreme Precipitation Events Based on TRMM Observations

    NASA Astrophysics Data System (ADS)

    Zhou, Y.; Lau, W. K.

    2012-12-01

    This study utilizes the Precipitation Feature (PF) database developed at the University of Utah to analyze extreme precipitation events from 13-year TRMM observations. Characteristics of instantaneous extreme volumetric PFs, their geophysical distributions and diurnal variations are examined and compared to those of intermediate and small systems. It is found that the instantaneous PF exhibits much larger scale range than daily gridded precipitation, with those at top 1% of PFs two orders of magnitude greater than the medium PF but contributing to over 50% of instantaneous rainfall. The study shows that extreme PFs are significantly larger, deeper and colder than the lower 80% of the PFs. NCEP reanalysis shows a systematic increase in surface moist static energy (MSE) with larger PFs but convective available potential energy (CAPE) levels off for extremely large systems. Mid-level relative humidity and total precipitable water increase consistently for increasingly heavy precipitation events, suggesting a potential role of increasing moisture in a warming climate in producing extreme precipitation events.

  14. 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.

  15. AN EVENT-BASED MODEL FOR WEB SERVICES COORDINATION Mohsen Rouached

    E-print Network

    Paris-Sud XI, Université de

    of Web services in B2B, B2C, and enterprize application integration environments will require the ability structure than can be described by just the definition of entry points. Indeed, to form real B2B or B2C

  16. An event-based model of braided river system aquifers heterogeneity based on Multiple Points Statistics

    NASA Astrophysics Data System (ADS)

    Renard, P.; Pirot, G.

    2012-12-01

    Braided-rivers are common in mountainous regions like the Swiss Alps. These dynamic systems generate highly heterogeneous deposits and form an important part of alluvial aquifers which are tapped for agriculture and drinking water supply. In this presentation, we propose to integrate large scale and high resolution LIDAR data in a pseudo genetic approach embedding Multiple Points Statistics (MPS) to model the heterogeneity of such aquifers. A way to build 3D sedimentary models is to use descriptive methods, which translate data into conceptual facies models but do not offer uncertainty quantification. Another possibility is the use of stochastic models but most of them do not include strong geological knowledge and their degree of realism can be rather weak. Another approach is to use process-based methods. In this work, we imitate the processes occurring during flood events, by building successive topographies with the Direct Sampling (DS) multiple point statistics algorithm. Each successive topography is conditioned by the previous one. All those steps are constrained by a series of LIDAR data sets allowing to train the algorithm. This is different from classical MPS models, since we do not directly use MPS to model the lithofacies directly, but instead to simulate the processes that lead to the heterogeneity in order to ensure that higher statistics that can be inferred from field data are accurately reproduced. The use of the DS is motivated by the fact that it an MPS technique allowing to co-simulate continuous variables. It is easy to condition to field data and offers a high degree of realism in the simulations. The underlying erosion-deposition process leaves some records of each event in the form of remaining layers, which are populated with facies of different granulometry, according to some predefined rules function of the geobody's shape and dimensions. Input parameters allow controlling the aggradation/degradation intensity.

  17. An Event-based Platform for Collaborative Threats Detection and Monitoring

    E-print Network

    Tucci, Sara

    , 2014 #12;1. Introduction Threats such as frauds and cyber attacks can have serious and mea- surable-the-shelf hardware and software with documented and well-known vulnerabilities. Although the sophistication of cyber attacks has increased over time, the technical knowledge required to exploit existing vulnerabilities

  18. Qualitative Event-based Diagnosis: Case Study on the Second International Diagnostic Competition

    E-print Network

    Daigle, Matthew

    of faults in engineering systems lies at the core of systems health management technologies. This paper as deviations in observed behavior from predicted nominal behavior. We incorporate addi- tional diagnostic is organized as follows. Section 2 overviews the diagnosis approach. Section 3 provides the system model

  19. Event-based aquifer-to-atmosphere modeling over the European CORDEX domain

    NASA Astrophysics Data System (ADS)

    Keune, J.; Goergen, K.; Sulis, M.; Shrestha, P.; Springer, A.; Kusche, J.; Ohlwein, C.; Kollet, S. J.

    2014-12-01

    Despite the fact that recent studies focus on the impact of soil moisture on climate and especially land-energy feedbacks, groundwater dynamics are often neglected or conceptual groundwater flow models are used. In particular, in the context of climate change and the occurrence of droughts and floods, a better understanding and an improved simulation of the physical processes involving groundwater on continental scales is necessary. This requires the implementation of a physically consistent terrestrial modeling system, which explicitly incorporates groundwater dynamics and the connection with shallow soil moisture. Such a physics-based system enables simulations and monitoring of groundwater storage and enhanced representations of the terrestrial energy and hydrologic cycles over long time periods. On shorter timescales, the prediction of groundwater-related extremes, such as floods and droughts, are expected to improve, because of the improved simulation of components of the hydrological cycle. In this study, we present a fully coupled aquifer-to-atmosphere modeling system over the European CORDEX domain. The integrated Terrestrial Systems Modeling Platform, TerrSysMP, consisting of the three-dimensional subsurface model ParFlow, the Community Land Model CLM3.5 and the numerical weather prediction model COSMO of the German Weather Service, is used. The system is set up with a spatial resolution of 0.11° (12.5km) and closes the terrestrial water and energy cycles from aquifers into the atmosphere. Here, simulations of the fully coupled system are performed over events, such as the 2013 flood in Central Europe and the 2003 European heat wave, and over extended time periods on the order of 10 years. State and flux variables of the terrestrial hydrologic and energy cycle are analyzed and compared to both in situ (e.g. stream and water level gauge networks, FLUXNET) and remotely sensed observations (e.g. GRACE, ESA ICC ECV soil moisture and SMOS). Additionally, the presented modeling system may be useful in the assessment of groundwater-related uncertainties in virtual reality and scenario simulations.

  20. An Early Warning System for Hypoglycemic/Hyperglycemic Events Based on Fusion of Adaptive Prediction Models

    PubMed Central

    Daskalaki, Elena; Nørgaard, Kirsten; Züger, Thomas; Prountzou, Aikaterini; Diem, Peter; Mougiakakou, Stavroula

    2013-01-01

    Introduction Early warning of future hypoglycemic and hyperglycemic events can improve the safety of type 1 diabetes mellitus (T1DM) patients. The aim of this study is to design and evaluate a hypoglycemia/hyperglycemia early warning system (EWS) for T1DM patients under sensor-augmented pump (SAP) therapy. Methods The EWS is based on the combination of data-driven online adaptive prediction models and a warning algorithm. Three modeling approaches have been investigated: (i) autoregressive (ARX) models, (ii) auto-regressive with an output correction module (cARX) models, and (iii) recurrent neural network (RNN) models. The warning algorithm performs postprocessing of the models? outputs and issues alerts if upcoming hypoglycemic/hyperglycemic events are detected. Fusion of the cARX and RNN models, due to their complementary prediction performances, resulted in the hybrid autoregressive with an output correction module/recurrent neural network (cARN)-based EWS. Results The EWS was evaluated on 23 T1DM patients under SAP therapy. The ARX-based system achieved hypoglycemic (hyperglycemic) event prediction with median values of accuracy of 100.0% (100.0%), detection time of 10.0 (8.0) min, and daily false alarms of 0.7 (0.5). The respective values for the cARX-based system were 100.0% (100.0%), 17.5 (14.8) min, and 1.5 (1.3) and, for the RNN-based system, were 100.0% (92.0%), 8.4 (7.0) min, and 0.1 (0.2). The hybrid cARN-based EWS presented outperforming results with 100.0% (100.0%) prediction accuracy, detection 16.7 (14.7) min in advance, and 0.8 (0.8) daily false alarms. Conclusion Combined use of cARX and RNN models for the development of an EWS outperformed the single use of each model, achieving accurate and prompt event prediction with few false alarms, thus providing increased safety and comfort. PMID:23759402

  1. 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.

  2. Event-Based Concepts for User-Driven Visualization Christian Tominskia,

    E-print Network

    Tominski, Christian

    important tool to support exploration and analysis of the large volumes of data we are facing today. However their interests are. (2) During visualization, matches of these interests are sought in the data. (3 and spatio-temporal data. Key words: Visualization, User, Event 1. Introduction Visual representations

  3. Multipath routing for cluster-based and event-based protocols in wireless sensor networks

    Microsoft Academic Search

    Thu Ngo Quynh; Thuy Tran Vinh; Mai Banh Thi Quynh

    2012-01-01

    Wireless Sensor Network (WSN) that consists of a large number of small sensing self-powered nodes is a promising approach for a variety of applications. Possible applications of WSN are of interest to the most diverse fields: environmental monitoring, warfare, child education, surveillance, micro-surgery and agriculture are only few examples. Due to limited power of sensor nodes that are distributed in

  4. Event-Based Modeling of Driver Yielding Behavior to Pedestrians at Two-Lane Roundabout Approaches

    PubMed Central

    Salamati, Katayoun; Schroeder, Bastian J.; Geruschat, Duane R.; Rouphail, Nagui M.

    2013-01-01

    Unlike other types of controlled intersections, drivers do not always comply with the “yield to pedestrian” sign at the roundabouts. This paper aims to identify the contributing factors affecting the likelihood of driver yielding to pedestrians at two-lane roundabouts. It further models the likelihood of driver yielding based on these factors using logistic regression. The models have been applied to 1150 controlled pedestrian crossings at entry and exit legs of two-lane approaches of six roundabouts across the country. The logistic regression models developed support prior research that the likelihood of driver yielding at the entry leg of roundabouts is higher than at the exit. Drivers tend to yield to pedestrians carrying a white cane more often than to sighted pedestrians. Drivers traveling in the far lane, relative to pedestrian location, have a lower probability of yielding to a pedestrian. As the speed increases the probability of driver yielding decreases. At the exit leg of the roundabout, drivers turning right from the adjacent lane have a lower propensity of yielding than drivers coming from other directions. The findings of this paper further suggest that although there has been much debate on pedestrian right-of-way laws and distinction between pedestrian waiting positions (in the street versus at the curb), this factor does not have a significant impact on driver yielding rate. The logistic regression models also quantify the effect of each of these factors on propensity of driver yielding. The models include variables which are specific to each study location and explain the impact size of each study location on probability of yielding. The models generated in this research will be useful to transportation professionals and researchers interested in understanding the factors that impact driver yielding at modern roundabouts. The results of the research can be used to isolate factors that may increase yielding (such as lower roundabout approach speeds), and can feasibly be incorporated into microsimulation algorithms to model driver yielding at roundabouts. PMID:24619314

  5. 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

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

    PubMed

    Schroeder, Bastian J; Rouphail, Nagui M

    2011-07-01

    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

  7. Synthesising Non-Anomalous Event-Based Controllers for Liveness Goals

    E-print Network

    Figueira, Santiago

    .piterman@leicester.ac.uk; S. Uchitel, Department of Computing, Imperial College, 180 Queen's Gate, London, SW7 2RH, UK; su2@doc.ic.ac.uk. Permission to make digital or hard copies of part or all of this work for personal

  8. 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 ? 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 ?. 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.

  9. Real-Time Processing of Media Streams: A Case for Event-Based Interaction

    Microsoft Academic Search

    Viktor S. Wold Eide; Frank Eliassen; Olav Lysne; Ole-christoffer Granmo

    2002-01-01

    There are many challenges in devising solutions for on- line content processing of live networked multimedia ses- sions. These include the computational complexity of fea- ture extraction and high-level concept recognition, the mas- sive amount of data to be analyzed under real-time require- ments and the intricate correspondence between low-level features and high-level concepts. Our approach to these challenges is

  10. Southern Hemisphere Biogeography Inferred by Event-Based Models: Plant versus Animal Patterns

    Microsoft Academic Search

    ISABEL SANMARTÍN; FREDRIK RONQUIST

    2004-01-01

    The Southern Hemisphere has traditionally been considered as having a fundamentally vicariant history. The common trans-Pacific disjunctions are usually explained by the sequential breakup of the supercontinent Gondwana during the last 165 million years, causing successive division of an ancestral biota. However, recent biogeographic studies, based on molecular estimates and more accurate paleogeographic reconstructions, indicate that dispersal may have been

  11. SUPERVISED MODEL TRAINING FOR OVERLAPPING SOUND EVENTS BASED ON UNSUPERVISED SOURCE SEPARATION

    E-print Network

    Virtanen, Tuomas

    with a database con- taining recordings from various contexts, against the baseline sys- tem trained without percentage units in the detection accuracy. Index Terms-- acoustic event detection, sound source separa- tion, supervised model training, acoustic pattern recognition 1. INTRODUCTION A sound event is a segment of audio

  12. An extensible framework for middleware design based on concurrent event-based AOP

    E-print Network

    Ferreira, Paulo

    , Luís Veiga, Paulo Ferreira Distributed Systems Group INESC-ID/Technical Univ. of Lisbon Rua Alves Redol in modular reusable com- ponents. However, the traditional methods of software de- composition fail of such devices (e.g. variable bandwidth, limited battery capacity, etc.) become an obsta- cle that considerably

  13. 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…

  14. Implementation of an airline recovery model in an event-based simulation

    E-print Network

    Rabbani, Fábio Faizi Rahnemay, 1978-

    2004-01-01

    Airlines maximize the use of their resources by minimizing the time between consecutive flight legs in their aircraft and crew schedules. As a result, bad weather or unscheduled aircraft maintenance events can have a ...

  15. EventCJ: a context-oriented programming language with declarative event-based context transition

    Microsoft Academic Search

    Tetsuo Kamina; Tomoyuki Aotani; Hidehiko Masuhara

    2011-01-01

    This paper proposes EventCJ, a context-oriented programming (COP) language that can modularly control layer activation based on user-defined events. In addition to defining context-specific behaviors by using existing COP constructs, the EventCJ programmer declares events to specify when and on which instance layer switching should happen, and layer transition rules to specify which layers should be activated\\/deactivated upon events. These

  16. A Simplified Dynamical Approach To The Study of Atmospheric Events Based On Data Fusion

    NASA Astrophysics Data System (ADS)

    Berardo, V.; Siccardi, F.; Taramasso, A. C.

    Improvements and developments in operational remote sensing technology make available high-resolution observations describing the hydrometeorological conditions associated with heavy precipitation events. This work deals with the possibility of combining different data sources to study the precipitation process. Data fusion seems to be an effective way to combine models and measurements from different sensors operating over a range of scales. The goal is to take advantage of the strengths of each source to improve the knowledge of deep convection mechanisms. Special attention is paid to weather radar data. Doppler radial wind data lead to the retrieval of quite reliable wind fields when more than one sensor overlaps its optical visibility range with another. The new Italian weather-radar coverage design requires to deeply analyse the capabilities of this measurement system, which is strongly linked to raindrop characteristics. A three-dimensional physically based rainfall-forecasting model is formulated with the aim of performing data fusion. The work focuses on a description of the primary processes, interacting at a variety of spatial and temporal scales, within a column of atmosphere associated with a convective cloud. Parameterization of the model compo- nents is based on hydrometeorological observations, including radar Doppler velocity data, satellite-infrared brightness temperature and ground-level measurements of tem- perature, pressure and dew point temperature. The capability of assimilating different types of data and observations helps to compensate the simplified dynamics and leads to an enhanced definition of the convective processes.

  17. 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

  18. An empirical-stochastic, event-based program for simulating inflow from a tributary network

    E-print Network

    California at Santa Barbara, University of

    , and detecting bed level change. INDEX TERMS: 1860 Hydrology: Runoff and streamflow; 1821 Hydrology: Floods; 1833 in flood events. It incorporates seasonality, event basis, and correlation in flood occurrence and flood002725. 1. Introduction [2] For a number of purposes (estimation of flood risk, sediment transport

  19. Event-based progression detection strategies using scanning laser polarimetry images of the human retina.

    PubMed

    Vermeer, K A; Lo, B; Zhou, Q; Vos, F M; Vossepoel, A M; Lemij, H G

    2011-09-01

    Monitoring glaucoma patients and ensuring optimal treatment requires accurate and precise detection of progression. Many glaucomatous progression detection strategies may be formulated for Scanning Laser Polarimetry (SLP) data of the local nerve fiber thickness. In this paper, several strategies, all based on repeated GDx VCC SLP measurements, are tested to identify the optimal one for clinical use. The parameters of the methods were adapted to yield a set specificity of 97.5% on real image series. For a fixed sensitivity of 90%, the minimally detectable loss was subsequently determined for both localized and diffuse loss. Due to the large size of the required data set, a previously described simulation method was used for assessing the minimally detectable loss. The optimal strategy was identified and was based on two baseline visits and two follow-up visits, requiring two-out-of-four positive tests. Its associated minimally detectable loss was 5-12 ?m, depending on the reproducibility of the measurements. PMID:21803348

  20. An Event-Based Paradigm for E-commerce Application Specification and Execution

    E-print Network

    Cambridge, University of

    Kingdom asa28@wharton.upenn.edu, {David.Eyers, Jean.Bacon}@cl.cam.ac.uk Abstract This paper describes, specifications (policies) are decomposed into events which, like operational events, are stored and animated participating as the purchased items (role)'. Naming and classification events will be describe in further

  1. Event-based PI Control of an Underactuated Biped J.W. Grizzle

    E-print Network

    Grizzle, Jessy W.

    , no actuation is applied between the stance leg and the ground, while all other joints are actuated. A rigid without actuation between the stance leg and ground is an important step in designing natural- ment conventions. Fig. 1. Example bipeds. No actuation is applied between the stance leg and the ground

  2. Historical Chronology of ENSO Events Based Upon Documentary Data From South America: Strengths and Limitations

    NASA Astrophysics Data System (ADS)

    Luc, O.

    2007-05-01

    The first reconstructions of past El Niño occurrences were proposed by W. Quinn twenty years ago. They were based on documentary evidence of anomalous rainfall episodes, destructive floods and other possible impacts of El Niño conditions in Peru and other South-American countries. It has been shown, later, that the El Niño chronological sequence covering the last four and a half centuries produced by Quinn needed a thorough revision since many so-called EN events had not occurred while some others had been overlooked. Beside the classical methodological problems met in historical climatology studies (reliability of data, confidence in the sources, primary and secondary information), the reconstruction of former EN events faces specific difficulties dealing with the significance of the indicators and their spatial location. For instance, strong precipitation anomalies during summer in Southern Ecuador and northern Peru and precipitation excess recorded in the preceding winter in central Chile constitute quite reliable proxies of El Niño conditions, in modern times. However this observed teleconnection pattern, which is useful to reinforce the interpretation of past EN occurrences, seems to have been inoperative before the early nineteenth century. It is interpreted that atmospheric circulation features during the Little Ice Age interfered with the teleconnection system linking the EN impacts in northern Peru and central Chile. As a consequence, how should be evaluated the significance of documented winter precipitation excess in central Chile in years during which there is drought evidence in northern Peru, during the sixteenth to eighteenth century? And vice versa, are former evidences for precipitation excess in northern Peru (prior to the nineteenth century) quite reliable indicators for EN conditions, even if the preceding winter was dry in the Valparaiso-Santiago region? Other specific problems met in the building-up of a consolidated EN chronological sequence deal with the non-homogeneity of the documentary records, the reconstruction of the paleo-events strength and the difficulty to cross check documentary data with other annually resolved records (corals, tree-rings and ice-core data). In spite of all these limitations, the documentation of former EN occurrences based upon written archives from colonial South-America remains an unavoidable and powerful tool to reconstruct a solid El Niño chronology for the last half millennium and to better understand the interplay of the different modes (at the interannual, decadal, multidecadal and centennial scales) of climate variations in this part of the world.

  3. Fast sensory motor control based on event-based hybrid neuromorphic-procedural system

    Microsoft Academic Search

    Tobi Delbrück; Patrick Lichtsteiner

    2007-01-01

    Abstract—Fast sensory-motor processing is challenging when using traditional frame-based cameras and computers. Here we show how a hybrid neuromorphic-procedural system consisting of an address-event silicon retina, a computer, and a servo motor can be used to implement a fast sensory-motor reactive controller totrack and block balls shot at a goal. The system consists of a 128x128 retina that asynchronously reports

  4. Event completion: Event based inferences distort memory in a matter of seconds

    Microsoft Academic Search

    Brent Strickland; Frank Keil

    2011-01-01

    We present novel evidence that implicit causal inferences distort memory for events only seconds after viewing. Adults watched videos of someone launching (or throwing) an object. However, the videos omitted the moment of contact (or release). Subjects falsely reported seeing the moment of contact when it was implied by subsequent footage but did not do so when the contact was

  5. 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

  6. 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.

  7. Event-based Information Extraction for the biomedical domain: the Caderige project

    Microsoft Academic Search

    Érick Alphonse; Sophie Aubin; Philippe Bessières; Gilles Bisson; Thierry Hamon; Sandrine Lagarrigue; Adeline Nazarenko; Alain-Pierre Manine; Claire Nédellec; Mohamed Ould Abdel Vetah; Thierry Poibeau; Davy Weissenbacher

    2006-01-01

    This paper gives an overview of the Caderige project. This project involves teams from different areas (biology, machine learning, natural language processing) in order to develop high- level analysis tools for extracting structured information from biological bibliographical databases, especially Medline. The paper gives an overview of the approach and compares it to the state of the art.

  8. DEVS Today: Recent Advances in Discrete Event-Based Information Technology

    E-print Network

    further, we stop to review the basic DEVS formalism within a larger framework for modeling and simulation provides a means of specifying a mathematical object called a system [3,4,5]. Basically, a system has specify discrete event system parameters. 1 Apparently, readers of Mandarin use a vertical line and use

  9. 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…

  10. Rediscovering Workflow Models from Event-Based Data using Little Thumb

    E-print Network

    van der Aalst, Wil

    . Consider for example ERP (Enterprise Resource Planning) systems such as SAP, PeopleSoft, Baan and Oracle systems such as SAP and Baan). The rediscovering technique proposed in this paper can deal with noise

  11. Infrastructure for Smart Cities: The Killer Application for Event-Based Computing

    Microsoft Academic Search

    Alejandro P. Buchmann

    2007-01-01

    Smart cities are part of the Ambient Intelligence vision that foresees the vanishing of computational devices into the fabric of society and the ubiquitous availability of intelligent services in support of our daily lives. In this vision we should not be burdened by conscious manipulation of devices and ever more powerful but also complex interfaces. Instead, devices should be able

  12. Event-based approach to money laundering data analysis and visualization

    Microsoft Academic Search

    Tat-Man Cheong; Yain-Whar Si

    2010-01-01

    Crime specific event patterns are crucial in detecting potential relationships among suspects in criminal networks. However, current link analysis tools commonly used in detection do not utilize such patterns for detecting various types of crimes. These analysis tools usually provide generic functions for all types of crimes and heavily rely on the user's expertise on the domain knowledge of the

  13. 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...

  14. 14 CFR 399.41 - Zones of limited suspension for international cargo rates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... (1) For all bulk rates (GCR's and SCR's) in the Atlantic region, 20 percent... (2) For all bulk rates (GCR's and SCR's) in the Pacific region, 15 percent... (3) For all bulk rates (GCR's and SCR's) in the Western Hemisphere...

  15. Violence among men and women in substance use disorder treatment: A multi-level event-based analysis

    Microsoft Academic Search

    Stephen T. Chermack; Andy Grogan-Kaylor; Brian E. Perron; Regan L. Murray; Peter De Chavez; Maureen A. Walton

    2010-01-01

    BackgroundThis study examined associations between acute alcohol and drug use and violence towards others in conflict incidents (overall, partner, and non-partner conflict incidents) by men and women recruited from substance use disorder (SUD) treatment.

  16. Violence Among Men and Women in Substance Use Disorder Treatment: A Multi-level Event-based Analysis

    PubMed Central

    Chermack, Stephen T.; Grogan-Kaylor, Andy; Perron, Brian E.; Murray, Regan L.; De Chavez, Peter; Walton, Maureen A.

    2010-01-01

    Background This study examined associations between acute alcohol and drug use and violence towards others in conflict incidents (overall, partner, and non-partner conflict incidents) by men and women recruited from substance use disorder (SUD) treatment. Methods Semi-structured interviews were used to obtain details about interpersonal conflict incidents (substance use, whether specific conflicts were with intimate partners or non-partners) in the 180 days pre-treatment. Participants for this study were selected for screening positive for past-year violence (N = 160; 77% men, 23% women). Results Multilevel multinomial regression models showed that after adjusting for clustering within individual participants, the most consistent predictors of violence across models were acute cocaine use (significant for overall, intimate partner and non-partner models), acute heavy alcohol use (significant for overall and non-partner models), and male gender (significant in all models). Conclusions This study was the first to explicitly examine the role of acute alcohol and drug use across overall, partner and non-partner conflict incidents. Consistent with prior studies using a variety of methodologies, alcohol, cocaine use and male gender were most consistently and positively related to violence severity (e.g., resulting in injury). The results provide important and novel event-level information regarding the relationship between acute alcohol and specific drug use and the severity of violence in interpersonal conflict incidents. PMID:20667666

  17. 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

  18. 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

  19. A novel regulatory event-based gene set analysis method for exploring global functional changes in heterogeneous genomic data sets

    Microsoft Academic Search

    Chien-Yi Tung; Chih-Hung Jen; Ming-Ta Hsu; Hsei-Wei Wang; Chi-Hung Lin

    2009-01-01

    BACKGROUND: Analyzing gene expression data by assessing the significance of pre-defined gene sets, rather than individual genes, has become a main approach in microarray data analysis and this has promisingly derive new biological interpretations of microarray data. However, the detection power of conventional gene list or gene set-based approaches is limited on highly heterogeneous samples, such as tumors. RESULTS: We

  20. conference on limestone hydrogeology, 2011, Besanon, France 91 Infiltration processes in karst using an event-based conceptual

    E-print Network

    Paris-Sud XI, Université de

    9th conference on limestone hydrogeology, 2011, Besançon, France 91 Infiltration processes in karst The aim of this study is to characterize karst infiltration processes during flood events using a rainfall on a classical karst devoted model with three connected reservoirs: SOIL (and epikarst) that feeds the aquifer

  1. Formal development method of control systems using the event-based B Case study : A parcel sorting device

    E-print Network

    Boyer, Edmond

    sorting device Olfa MOSBAHI Jacques JARAY Leila JEMNI BEN AYED Faculty of Sciences of Tunis INRIA Lorraine Faculty of Sciences of Tunis University Tunis El Manar II LORIA-INPL University Tunis El Manar II Tunis, Tunisie Nancy, France Tunis, Tunisie olfa.mosbahi@loria.fr jacques.jaray@loria.fr leila

  2. Detection of water-quality contamination events based on multi-sensor fusion using an extented Dempster-Shafer method

    NASA Astrophysics Data System (ADS)

    Hou, Dibo; He, Huimei; Huang, Pingjie; Zhang, Guangxin; Loaiciga, Hugo

    2013-05-01

    This study presents a method for detecting contamination events of sources of drinking water based on the Dempster-Shafer (D-S) evidence theory. The detection method has the purpose of protecting water supply systems against accidental and intentional contamination events. This purpose is achieved by first predicting future water-quality parameters using an autoregressive (AR) model. The AR model predicts future water-quality parameters using recent measurements of these parameters made with automated (on-line) water-quality sensors. Next, a probabilistic method assigns probabilities to the time series of residuals formed by comparing predicted water-quality parameters with threshold values. Finally, the D-S fusion method searches for anomalous probabilities of the residuals and uses the result of that search to determine whether the current water quality is normal (that is, free of pollution) or contaminated. The D-S fusion method is extended and improved in this paper by weighted averaging of water-contamination evidence and by the analysis of the persistence of anomalous probabilities of water-quality parameters. The extended D-S fusion method makes determinations that have a high probability of being correct concerning whether or not a source of drinking water has been contaminated. This paper's method for detecting water-contamination events was tested with water-quality time series from automated (on-line) water quality sensors. In addition, a small-scale, experimental, water-pipe network was tested to detect water-contamination events. The two tests demonstrated that the extended D-S fusion method achieves a low false alarm rate and high probabilities of detecting water contamination events.

  3. 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

  4. 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...

  5. REGULAR PAPER SUBMITTED TO IEEE TRANSACTIONS ON ROBOTICS 1 Event-based Stabilization of Periodic Orbits for

    E-print Network

    Grizzle, Jessy W.

    describing the stance phase and a discrete map describing the impact event, that is, the non-stance leg bipedal robot with series-compliant actuators and point feet, against external disturbances as well feet and series-compliant actuators (see Fig. 1). During the single support phase, the robot has 13

  6. In-Silico Effects of Mg2+ Diffusion Rates on Stochastic Event Based Simulation of the PhoPQ System

    Microsoft Academic Search

    Preetam Ghosh; Kalyan Basu; Sajal K. Das; Chaoyang Zhang

    2009-01-01

    The challenge today is to develop a modeling and simulation paradigm that integrates structural, molecular and genetic data for a quantitative understanding of physiology and behavior of biological processes at multiple scales. This paradigm requires techniques that maintain a reasonable accuracy of the biological process and also reduces the computational overhead. This objective motivates the use of new methods that

  7. 638 IEEE TRANSACTIONS ON MULTIMEDIA, VOL. 7, NO. 4, AUGUST 2005 Multimedia Event-Based Video Indexing

    E-print Network

    Fan, Jianping

    the Allen temporal interval relations and allows for proper inclusion of context and synchronization of the heterogeneous information sources involved in multimodal video analysis. To demonstrate the viability of our of semantic events, we compare three different machine learning techniques, i.c. C4.5 decision tree, maximum

  8. 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...

  9. Estimating the response effect of future events based on historical analogy: A methodology and illustration on generic substitution of brand-name drug sales following patent expiration

    Microsoft Academic Search

    Wilfried R. Vanhonacker; Lydia J. Price

    1995-01-01

    Managerial decisions often are made with considerable uncertainty about their possible effects. In assessing such problems, we often rely in an ad hoc fashion on analogous situations in the hope that they will shed light on the possible outcomes. This paper introduces a formal methodology for transferring information or data from one situation to another. A simple recursive least-squares approach

  10. A technique for short-term warning of solar energetic particle events based on flare location, flare size, and evidence of particle escape

    Microsoft Academic Search

    M. Laurenza; E. W. Cliver; J. Hewitt; M. Storini; A. G. Ling; C. C. Balch; M. L. Kaiser

    2009-01-01

    We have developed a technique to provide short-term warnings of solar energetic proton (SEP) events that meet or exceed the Space Weather Prediction Center threshold of J (>10 MeV) = 10 pr cm?2 s?1 sr?1. The method is based on flare location, flare size, and evidence of particle acceleration\\/escape as parameterized by flare longitude, time-integrated soft X-ray intensity, and time-integrated

  11. Linguistic scope-based and biological event-based speculation and negation annotations in the BioScope and Genia Event corpora

    PubMed Central

    2011-01-01

    Background The treatment of negation and hedging in natural language processing has received much interest recently, especially in the biomedical domain. However, open access corpora annotated for negation and/or speculation are hardly available for training and testing applications, and even if they are, they sometimes follow different design principles. In this paper, the annotation principles of the two largest corpora containing annotation for negation and speculation – BioScope and Genia Event – are compared. BioScope marks linguistic cues and their scopes for negation and hedging while in Genia biological events are marked for uncertainty and/or negation. Results Differences among the annotations of the two corpora are thematically categorized and the frequency of each category is estimated. We found that the largest amount of differences is due to the issue that scopes – which cover text spans – deal with the key events and each argument (including events within events) of these events is under the scope as well. In contrast, Genia deals with the modality of events within events independently. Conclusions The analysis of multiple layers of annotation (linguistic scopes and biological events) showed that the detection of negation/hedge keywords and their scopes can contribute to determining the modality of key events (denoted by the main predicate). On the other hand, for the detection of the negation and speculation status of events within events, additional syntax-based rules investigating the dependency path between the modality cue and the event cue have to be employed. PMID:22166355

  12. Beam-splitters don't have memory: a comment on "Event-based corpuscular model for quantum optics experiments'' by K.Michielsen et al

    E-print Network

    Radu Ionicioiu

    2010-12-03

    In a recent article (arXiv:1006.1728) K.Michielsen et al. claim that a simple corpuscular model can explain many quantum optics experiments. We discuss these claims and show that their proposal fails at several levels. Finally, we propose an experiment to falsify the model.

  13. Comment on "Beam-splitters don't have memory: a comment on "Event-based corpuscular model for quantum optics experiments" by K.Michielsen et al."

    E-print Network

    V. A. Kuz'menko

    2010-12-10

    R. Ionicioiu in arXiv:1012.0647 claims that beam-splitters do not have memory. This is the unproved statement. From other side, such small quantum objects as molecules, atoms and even photons have memory, which is connected with the inequality of forward and reversed processes in quantum physics.

  14. Separately accounting for uncertainties in rainfall and runoff: Calibration of event-based conceptual hydrological models in small urban catchments using Bayesian method

    NASA Astrophysics Data System (ADS)

    Sun, Siao; Bertrand-Krajewski, Jean-Luc

    2013-09-01

    Uncertainty analysis of hydrological models is usually based on model calibration, and the Bayesian method is a popular way to evaluate the uncertainty. The traditional Bayesian method usually uses lumped model residuals to form the likelihood function, where uncertainty in inputs (rainfall) is not explicitly addressed. This paper compares three approaches based on Bayesian inferences, considering rainfall uncertainty either implicitly or explicitly in calibration. Consistent parameter estimation and reliable quantification of predictive uncertainty are mainly examined. When rainfall uncertainty is explicitly treated in calibration, several rainfall observations at one-minute time steps are grouped to share one multiplier to consider the possible observation errors. The appropriate grouping strategy that balances the representativeness and the complexity of the problem is suggested. The application of the methods considered in this study focuses on small urban catchments (<200 ha) with a small temporal scale (1 min time step), in contrast to most literature studies dealing with larger catchments monitored at larger time steps. It is found that uncertainty in rainfall has a minor contribution to the total uncertainty in runoff estimation, and this minor role can be explained by the low pass filter effect of the linear reservoir model. However, the approach explicitly accounting for input uncertainty results in more informed knowledge for uncertainties related with hydrological model calibrations, which can possibly provide an estimation of uncertainty attributed to rainfall records. It should be noted that rainfall error estimates can compensate model structural uncertainty that is not explicitly addressed in this study.

  15. Event-based measurement of boundary-layer winds and topographic effects with a small unmanned aircraft system (sUas)

    NASA Astrophysics Data System (ADS)

    Riddell, K.; Hugenholtz, C.

    2012-12-01

    Numerical models are invaluable tools for developing and testing hypotheses about interactions and feedbacks between wind and topography. However, field-based measurements are equally important for building and enhancing confidence in model output. Several field methods are available, including conventional approaches using tall masts equipped with an array of anemometers, as well as weather balloons, but few methods are able to match the level of detail available in model simulations of topographically-modified windflow. Here we propose an alternative method that may enhance numerical models. The method involves a small unmanned aircraft system (sUas) equipped with a meteorological sensor payload. The sUas is a two blade helicopter that weighs 5.5 kg, and has a length of 1.32 m. We designed a simple measurement and control system using an Arduino micro-controller, which acquired measurements at pre-defined coordinates autonomously. The entire survey was pre-configured and uploaded to the aircraft, effectively avoiding the need for manual aircraft operation and data collection. We collected raw measurements at each waypoint, yielding a point cloud of windspeed data. During test flights the sUas was able to maintain a stable position (± 0.6 m vertical and horizontal) in wind speeds up to 50 km/h. We used the raw data to map the wind speed-up ratio relative to a reference anemometer. Although it would be preferable to acquire continuous measurements at each waypoint, the sUas method only provides a snapshot of wind at each location. However, despite this limitation, the sUas does fill a void in terms of spatial measurements within the boundary layer. It may be possible to enhance this method in the future through deployment of sUas swarms that measure wind concurrently at many locations. Furthermore, other sensors can be deployed on sUas for measuring aeolian processes such as dust.

  16. Badhwar–O’Neill galactic cosmic ray model update based on advanced composition explorer (ACE) energy spectra from 1997 to present

    Microsoft Academic Search

    P. M. O’Neill

    2006-01-01

    Accurate knowledge of the interplanetary Galactic Cosmic Ray (GCR) environment is critical to planning and operating manned space flight to the moon and beyond. In the early 1990s, Badhwar and O’Neill developed a GCR model based on balloon and satellite data from 1954 to 1992. Since August 1997 the Advanced Composition Explorer (ACE) has provided significantly more accurate GCR energy

  17. Badhwar O'Neill galactic cosmic ray model update based on advanced composition explorer (ACE) energy spectra from 1997 to present

    Microsoft Academic Search

    P. M. O'Neill

    2006-01-01

    Accurate knowledge of the interplanetary Galactic Cosmic Ray (GCR) environment is critical to planning and operating manned space flight to the moon and beyond. In the early 1990s, Badhwar and O'Neill developed a GCR model based on balloon and satellite data from 1954 to 1992. Since August 1997 the Advanced Composition Explorer (ACE) has provided significantly more accurate GCR energy

  18. The cosmic ray source abundance of CSi isotopes: Dependence upon nuclear interaction cross sections

    Microsoft Academic Search

    Guzik

    1993-01-01

    New measurements of the Galactic Cosmic Ray (GCR) isotopic composition in the charge range C to Si are now becoming available. The GCR source composition of these isotopes are particularly interesting as they are synthesized by a broad range of processes requiring very different astrophysical conditions. However, these source abundances are obtained from the GCR measurements only by unfolding the

  19. Influence of cosmic-ray variability on the monsoon rainfall and temperature

    E-print Network

    Badruddin,

    2014-01-01

    We study the role of galactic cosmic ray (GCR) variability in influencing the rainfall variability in Indian Summer Monsoon Rainfall (ISMR) season. We find that on an average during 'drought' (low ISMR) periods in India, GCR flux is decreasing, and during 'flood' (high ISMR) periods, GCR flux is increasing. The results of our analysis suggest for a possibility that the decreasing GCR flux during the summer monsoon season in India may suppress the rainfall. On the other hand, increasing GCR flux may enhance the rainfall. We suspect that in addition to real environmental conditions, significant levitation/dispersion of low clouds and hence reduced possibility of collision/coalescence to form raindrops suppresses the rainfall during decreasing GCR flux in monsoon season. On the other hand, enhanced collision/coalescence efficiency during increasing GCR flux due to electrical effects may contribute to enhancing the rainfall. Based on the observations, we put forward the idea that, under suitable environmental con...

  20. Dispatch R539 Cytokinin action: Two receptors better than one?

    E-print Network

    Estelle, Mark

    of plants [4]. To investigate the function of GCR1, Plakidou-Dymock et al. [4] generated transgenic, no expression of GCR1 could be detected in the transgenic plants by RT-PCR. This phenotype is suggestive of a hormonal defect, so Plakidou-Dymock et al. [4] examined the responses of the transgenic plants to a nu

  1. Issues in deep space radiation protection

    Microsoft Academic Search

    J. Miller; C. Zeitlin; L. Heilbronn; F. A. Cucinotta; G. D. Badhwar; A. K. Noor; M. Y. Kim; F. F. Badavi; J. H. Heinbockel

    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

  2. Badhwar - O'Neill galactic cosmic ray model update based on Advanced Composition Explorer (ACE) energy spectra from 1997 to present

    Microsoft Academic Search

    P. O'Neill

    2004-01-01

    Accurate knowledge of the interplanetary Galactic Cosmic Ray (GCR) environment is critical to planning and operating manned space flight to the moon and beyond. In the early 1990's Badhwar and O'Neill developed a GCR model based on balloon and satellite data from 1954 to 1992. This model accurately accounts for solar modulation of each element (hydrogen -- iron) by propagating

  3. Occurence 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...

  4. Martian Radiation Environment Experiment (MARIE)

    Microsoft Academic Search

    Gautam D. Badhwar

    1999-01-01

    Space radiation presents a very serious hazard to crews of interplanetary human missions. The two sources of this radiation are the galactic cosmic rays (GCR) and solar energetic particle (SEP) events. The GCR provides a steady source of low dose rate radiation that is primarily responsible for stochastic effects, such as cancer, and can effect the response of the central

  5. Assessing access of galactic cosmic rays at Moon's orbit

    Microsoft Academic Search

    Chia-Lin Huang; Harlan E. Spence; Brian T. Kress

    2009-01-01

    Characterizing the lunar radiation environment is essential for preparing future robotic and human explorations on lunar bases. Galactic cosmic rays (GCR) represent one source of ionizing radiation at the Moon that poses a biological risk. Because GCR are charged particles, their paths are affected by the magnetic fields along their trajectories. Unlike the Earth, the Moon has no strong, shielding

  6. 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.

  7. Influence of cosmic-ray variability on the monsoon rainfall and temperature

    NASA Astrophysics Data System (ADS)

    Badruddin; Aslam, O. P. M.

    2015-01-01

    We study the role of galactic cosmic ray (GCR) variability in influencing the rainfall variability in Indian Summer Monsoon Rainfall (ISMR) season. We find that on an average during 'drought' (low ISMR) periods in India, GCR flux is decreasing, and during 'flood' (high ISMR) periods, GCR flux is increasing. The results of our analysis suggest for a possibility that the decreasing GCR flux during the summer monsoon season in India may suppress the rainfall. On the other hand, increasing GCR flux may enhance the rainfall. We suspect that in addition to real environmental conditions, significant levitation/dispersion of low clouds and hence reduced possibility of collision/coalescence to form raindrops suppresses the rainfall during decreasing GCR flux in monsoon season. On the other hand, enhanced collision/coalescence efficiency during increasing GCR flux due to electrical effects may contribute to enhancing the rainfall. Based on the observations, we put forward the idea that, under suitable environmental conditions, changing GCR flux may influence precipitation by suppressing/enhancing it, depending upon the decreasing/increasing nature of GCR flux variability during monsoon season in India, at least. We further note that the rainfall variability is inversely related to the temperature variation during ISMR season. We suggest an explanation, although speculative, how a decreasing/increasing GCR flux can influence the rainfall and the temperature. We speculate that the proposed hypothesis, based on the Indian climate data can be extended to whole tropical and sub-tropical belt, and that it may contribute to global temperature in a significant way. If correct, our hypothesis has important implication for the sun - climate link.

  8. 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.

  9. 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.

  10. 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,

  11. Comparison of Heating Methods for In-Situ Oil Shale Extraction

    E-print Network

    Hazra, Kaushik Gaurav

    2014-04-29

    . CRUSH Chevron’s technology for the recovery and in-situ upgrading of oil shale Cum Cumulative viii CWE Cold water equivalent EF Electrofrac EOS Equation of state GCR Gas combustion retort GFC Geothermic fuel cell GPRS...

  12. Research article Expression and evolution of the phosphoinositide-specific

    E-print Network

    Brendel, Volker

    MurashigeeSkoog salts, dehydration, and the plant hormone abscisic acid. Results of this and previous studies, inositol 1,4,5-trisphosphate; DAG, 1,2-diacylglycerol; MS, MurashigeeSkoog; ABA, abscisic acid; GCR1, G

  13. Alert, Response, and Capacity Building under the International Health Regulations

    MedlinePLUS

    ... the IHR About IHR A global system for alert and response A multi-hazard dimension Country capacity ... is led by the Department of Global Capacities Alert and Response (GCR). IHR Emergency Committee The Emergency ...

  14. Catalysinganenergyrevolution Nuclear Failures

    E-print Network

    Laughlin, Robert B.

    construction Fast Breeder Reactor (FBR) GCR reactor Heavy of nuclear power 10 Safety: lessons learned or lessons still to come? 12 Security: secrecy and unpredictable, this merged with Framatome, the nuclear reactor builder, to create the Areva group. Currently, 96

  15. Identification of Licopyranocoumarin and Glycyrurol from Herbal Medicines as Neuroprotective Compounds for Parkinson's Disease

    PubMed Central

    Fujimaki, Takahiro; Saiki, Shinji; Tashiro, Etsu; Yamada, Daisuke; Kitagawa, Mitsuhiro; Hattori, Nobutaka; Imoto, Masaya

    2014-01-01

    In the course of screening for the anti-Parkinsonian drugs from a library of traditional herbal medicines, we found that the extracts of choi-joki-to and daio-kanzo-to protected cells from MPP+-induced cell death. Because choi-joki-to and daio-kanzo-to commonly contain the genus Glycyrrhiza, we isolated licopyranocoumarin (LPC) and glycyrurol (GCR) as potent neuroprotective principals from Glycyrrhiza. LPC and GCR markedly blocked MPP+-induced neuronal PC12D cell death and disappearance of mitochondrial membrane potential, which were mediated by JNK. LPC and GCR inhibited MPP+-induced JNK activation through the suppression of reactive oxygen species (ROS) generation, thereby inhibiting MPP+-induced neuronal PC12D cell death. These results indicated that LPC and GCR derived from choi-joki-to and daio-kanzo-to would be promising drug leads for PD treatment in the future. PMID:24960051

  16. Janice L. Huff, Ph.D. Francis A. Cucinotta, Ph.D.

    E-print Network

    & Degenerative Tissue Risks cataracts, heart-disease, etc. ·Acute Radiation Sickness Prodromal risks (nausea, vomiting, fatigue) Lens changes in cataracts (E. Blakely) First experiments for leukemia induction with GCR

  17. Variations of galactic cosmic rays: modeling and observations

    NASA Astrophysics Data System (ADS)

    Gil, Agnieszka

    We analyze relationships of different classes of galactic cosmic ray (GCR) intensity variations with parameters of solar wind, solar and geomagnetic activities, studding profiles of amplitudes and rigidity spectra. We demonstrate that the amplitudes of the first, second and third harmonics of the 27-day variation of the GCR intensity changes in a similar way, being greater in the A > 0 than in A < 0 polarity periods. We show that the amplitudes of the 27-day variation of the GCR anisotropy are greater in the A > 0 than in A < 0 polarity periods. The larger amplitudes of the 27-day variations of the GCR anisotropy and intensity in the minimum epochs of solar activity for the A > 0 polarity period than for the A < 0 period are related with the heliolongitudinal asymmetry of the solar wind velocity. We reveal the long -lived (˜22 years) active region of the heliolongitudes being the source of the long-lived 27-day variation of the solar wind velocity during the A > 0 polarity period. The 27-day variations of the GCR intensity and anisotropy have a sporadic character; appear and disappear as a wave packages with an average duration of 5-7 solar rotations. The ampli-tudes of the 27-day variations of the GCR intensity and anisotropy do not depend on the tilt angles of the heliospheric neutral sheet in both the A > 0 and A < 0 periods. We show that the rigidity spectra of the first, second and third harmonics of the 27-day variation of the GCR intensity change in a analogous manner, being hard in the maximum epochs and soft in the minimum epochs of solar activity. We ascribe this finding to the alternation of the sizes of the modulation regions of the 27-day variation of the GCR intensity in different epochs of solar activity. We also show that the temporal changes of the power rigidity spectrum of the harmonics of the 27-day variation of the GCR intensity are negatively correlated with the rigidity spectrum of the 11-year variation of the galactic cosmic ray intensity. We propose the full 3-D stationary model describing the GCR variations including diffusion, convection, drift and the energy changes of the particles based on the Parker's transport equa-tion. We show that our models explain well the profiles of the behavior of the amplitudes and the rigidity spectrum exponent ? of the GCR variations. Our theoretical calculations are in a good agreement with the results obtained based on the neutron monitors experimental data.

  18. On the depth-dependent production of radionuclides (44?A?59) by solar protons in extraterrestrial matter

    Microsoft Academic Search

    R. Michel; G. Brinkmann

    1980-01-01

    In order to interpret cosmogenic radionuclides in extraterrestrial matter one has to differentiate between p- and ?-induced\\u000a reactions with solar (SCR) and with galactic (GCR) cosmic rays. Our earlier studies have shown that for a satisfactory description\\u000a of GCR-interactions with dense matter rather few but characteristic high energy cross sections are required. In contrast,\\u000a for the low and medium energy

  19. Composite Materials for Radiation Shielding During Deep Space Missions

    NASA Technical Reports Server (NTRS)

    Grugel, R. N.; Watts, J.; Adams, J. H.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Minimizing radiation exposure from the galactic cosmic ray (GCR) environment during deep space missions is essential to human health and sensitive instrument survivability. Given the fabrication constraints of space transportation vehicles protective shielding is, consequently, a complicated materials issue. These concerns are presented and considered in view of some novel composite materials being developed/suggested for GCR shielding applications. Advantages and disadvantages of the composites will be discussed as well as the need for coordinated testing/evaluation and modeling efforts.

  20. Movement Patterns of Wintering Lesser Scaup in Grand Calumet River—Indiana Harbor Canal, Indiana

    Microsoft Academic Search

    Christine M. Custer; Thomas W. Custer; Daniel W. Sparks; Randy K. Hines; Christopher O. Kochanny

    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

  1. Mph1p promotes gross chromosomal rearrangement through partial inhibition of homologous recombination.

    PubMed

    Banerjee, Soma; Smith, Stephanie; Oum, Ji-Hyun; Liaw, Hung-Jiun; Hwang, Ji-Young; Sikdar, Nilabja; Motegi, Akira; Lee, Sang Eun; Myung, Kyungjae

    2008-06-30

    Gross chromosomal rearrangement (GCR) is a type of genomic instability associated with many cancers. In yeast, multiple pathways cooperate to suppress GCR. In a screen for genes that promote GCR, we identified MPH1, which encodes a 3'-5' DNA helicase. Overexpression of Mph1p in yeast results in decreased efficiency of homologous recombination (HR) as well as delayed Rad51p recruitment to double-strand breaks (DSBs), which suggests that Mph1p promotes GCR by partially suppressing HR. A function for Mph1p in suppression of HR is further supported by the observation that deletion of both mph1 and srs2 synergistically sensitize cells to methyl methanesulfonate-induced DNA damage. The GCR-promoting activity of Mph1p appears to depend on its interaction with replication protein A (RPA). Consistent with this observation, excess Mph1p stabilizes RPA at DSBs. Furthermore, spontaneous RPA foci at DSBs are destabilized by the mph1Delta mutation. Therefore, Mph1p promotes GCR formation by partially suppressing HR, likely through its interaction with RPA. PMID:18591428

  2. DESPIKING OF SPACECRAFT ENERGETIC PROTON FLUX TO STUDY GALACTIC COSMIC-RAY MODULATION

    SciTech Connect

    Qin, G.; Zhao, L.-L. [State Key Laboratory of Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190 (China); Chen, H.-C., E-mail: gqin@spaceweather.ac.cn, E-mail: llzhao@spaceweather.ac.cn, E-mail: chchao@mail.ustc.edu.cn [Laboratory of Geophysical experiment, Institute of Geophysics, China Earthquake Administration, Beijing 100081 (China)

    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.

  3. 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.

  4. Cosmogenic-nuclide production by primary cosmic-ray protons

    SciTech Connect

    Reedy, R.C.

    1985-01-01

    The production rates of cosmogenic nuclides 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 GCR, the exceptions being nuclides made only by high-energy reactions (like Be-10). Because the particle fluxes inside meteorites and other large objects in space include many secondary neutrons, the production rates and ratios inside large objects are often very different from those by just the primary GCR protons. Thus it is possible to determine, by examining its cosmogenic nuclides, if a small object, such as found among deep-sea spherules, was small in space or broken from a meteorite. Because heliospherical modulation and other interactions change the GCR particle spectrum, the production of cosmogenic nuclides by the GCR particles outside the heliosphere will be different from that by modulated GCR primaries. Production rates and ratios for cosmogenic nuclides would be able to identify small particles, possibly interstellar in origin, that were exposed to an unmodulated spectrum of GCR particles and to characterize the spectrum of particles to which they were exposed. 6 refs., 1 tab.

  5. 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.

  6. The influence of galactic cosmic ray on all India annual rainfall and temperature

    NASA Astrophysics Data System (ADS)

    Chaudhuri, Sutapa; Pal, Jayanti; Guhathakurta, Suchandra

    2015-02-01

    The inverse relation between galactic cosmic ray (GCR) and sunspot numbers (SSN) suggests that the increase (decrease) in GCR count is linked with low (high) solar activity. The present study attempts to reveal the influence of GCR on all India annual rainfall and temperature during the period from 1953 to 2005. The inter-annual variation depicts that during the transition from maximum to minimum count of GCR, the rainfall anomaly shows alternative variation over India. Similar variation has also been observed for maximum temperature. Implementation of Fourier analysis shows an 11 year cycle of cosmic ray and depicts an increase in GCR count in the 11 year interval during the study period. The Fourier analysis of all India annual rainfall (AIR) and temperature also shows an 11 year cycle with a decreasing trend during the 11 year interval. The inter-decadal variation shows that during high GCR count there is a possibility of decrease in rainfall and minimum temperature but an increase in maximum temperature. The seasonal correlation shows a possible proportional association between cosmic ray and rainfall during the post monsoon season. The result further depicts that the sunspot number and temperature is positively correlated during the post-monsoon season. The correlation map of rainfall and temperature shows a meager but significant correlation with cosmic ray over some parts of West and East Indian coasts.

  7. 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.

  8. 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.

  9. 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.

  10. Regulation of gross chromosomal rearrangements by ubiquitin and SUMO ligases in Saccharomyces cerevisiae.

    PubMed

    Motegi, Akira; Kuntz, Karen; Majeed, Anju; Smith, Stephanie; Myung, Kyungjae

    2006-02-01

    Gross chromosomal rearrangements (GCRs) are frequently observed in many cancers. Previously, we showed that inactivation of Rad5 or Rad18, ubiquitin ligases (E3) targeting for proliferating cell nuclear antigen (PCNA), increases the de novo telomere addition type of GCR (S. Smith, J. Y. Hwang, S. Banerjee, A. Majeed, A. Gupta, and K. Myung, Proc. Natl. Acad. Sci. USA 101:9039-9044, 2004). GCR suppression by Rad5 and Rad18 appears to be exerted by the RAD5-dependent error-free mode of bypass DNA repair. In contrast, Siz1 SUMO ligase and another ubiquitin ligase, Bre1, which target for PCNA and histone H2B, respectively, have GCR-supporting activities. Inactivation of homologous recombination (HR) proteins or the helicase Srs2 reduces GCR rates elevated by the rad5 or rad18 mutation. GCRs are therefore likely to be produced through the restrained recruitment of an HR pathway to stalled DNA replication forks. Since this HR pathway is compatible with Srs2, it is not a conventional form of recombinational pathway. Lastly, we demonstrate that selection of proper DNA repair pathways to stalled DNA replication forks is controlled by the Mec1-dependent checkpoint and is executed by cooperative functions of Siz1 and Srs2. We propose a mechanism for how defects in these proteins could lead to diverse outcomes (proper repair or GCR formation) through different regulation of DNA repair machinery. PMID:16449653

  11. 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 TNF?, a strong pro-inflammatory mediator in numerous inflammatory diseases, compromises the protective function of the glucocorticoid receptor (GR) against TNF?-induced lethal inflammation. Indeed, protection of mice by dexamethasone against TNF? lethality was completely abolished when it was administered after TNF? stimulation, indicating compromised GR function upon TNF? challenge. TNF?-induced GCR was further demonstrated by impaired GR-dependent gene expression in the liver. Furthermore, TNF? down-regulates the levels of both GR mRNA and protein. However, this down-regulation seems to occur independently of GC production, as TNF? 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 TNF?-induced shock, as supported by our studies with GR heterozygous mice. We propose that by inducing GCR, TNF? 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 TNF? is intimately involved. PMID:21646349

  12. 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

  13. Step-like Flux Variations of Quiet-time Low-energy Proton and He Nuclei In 1978-90 Near 1 Au

    NASA Astrophysics Data System (ADS)

    Zeldovich, M.; Logachev, Yu.; Kecskemety, K.

    In the period of 1978-81 the galactic cosmic ray (GCR) intensity decreased in three steps whereas in 1989-90 two prominent GCR steps were observed. At the same time, energetic (1-10 MeV/n) proton and He populations, based on monthly minima of quiet-time fluxes near 1 AU, exhibited a step-like variation as well, but in a phase opposite to GCR modulation. Each low-energy particle step ended with the mostly low in the year proton and He nuclei intensity simultaneously with a temporary in- crease of GCR flux. Here five different particle steps observed during the ascending phases of the 21st and 22nd solar cycles are investigated, each of which appeared fol- lowing steps of GCR modulation. The analysis of the p/He ratio around steps yields a very low value (5 to 25)at the end of each step, while the intensities of low-energy pro- ton and He fluxes exhibit the lowest values marking the presence of additional proton population to background during modulation step. Discussed are the possibilities that Global Merged Interaction Regions and variations of solar activity are responsible for the observed stepwise variations in the quiet-time fluxes of 1-10 MeV/n particles and simultaneous variations of galactic particles.

  14. Step-like flux variations of quiet-time low-energy protons and HE nuclei in 1978-90 near 1 AU

    NASA Astrophysics Data System (ADS)

    Zeldovich, M. A.; Logachev, Yu. I.; Kecskemety, K.

    2001-08-01

    In the period of 1978-81 the galactic cosmic ray (GCR) intensity decreased in three steps whereas in 1989-90 one prominent GCR step was observed. At the same time, energetic (1-10 MeV/n) proton and He populations, based on monthly minima of quiet-time fluxes near 1 AU, exhibited a step-like variation as well, but in a phase opposite to GCR modulation. Each low-energy particle step ended with the yearly lowest proton and He intensity simultaneously with a temporary increase of GCR flux. Here five different particle steps observed during the ascending phases of the 21st and 22nd solar cycles are investigated, each of which appeared following steps of GCR modulation. The analysis of the p/He ratio around steps yields a very low value (5 to 25) at the end of each step, while the intensities of low-energy proton and He fluxes exhibit the lowest values marking the presence of a proton population additional to background near modulation steps. Discussed are the possibilities that Global Merged Interaction Regions and variations of solar activity are responsible for the observed stepwise variations in the quiet-time fluxes of 1-10 MeV/n particles and simultaneous variations of galactic particles.

  15. 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.

  16. 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.

  17. 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 ?E* 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.

  18. 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.

  19. 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.

  20. 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

  1. Modeling and experimental study of the 27-day variation of galactic cosmic-ray intensity for a solar-wind velocity depending on heliolongitude

    E-print Network

    Alania, M V; Wawrzynczak, A

    2015-01-01

    We develop a three dimensional (3-D) model of the 27-day variation of galactic cosmic ray (GCR) intensity with a spatial variation of the solar wind velocity. A consistent, divergence-free interplanetary magnetic field is derived by solving the corresponding Maxwell equations with a variable solar wind speed, which reproduces in situ observed experimental data for the time interval to be analyzed (24 August 2007-28 February 2008). We perform model calculations for the GCR intensity using the variable solar wind and the corresponding magnetic field. Results are compatible with experimental data; the correlation coefficient between our model predictions and observed 27-day GCR variation is 0.80 0.05.

  2. 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.

  3. 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.

  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. Modulation of UK lightning and the atmospheric electric circuit by heliospheric magnetic field polarity

    NASA Astrophysics Data System (ADS)

    Owens, Mathew; Scott, Chris; Lockwood, Mike; Barnard, Luke; Harrison, Giles; Nicoll, Keri; Watt, Clare; Bennett, Alec

    2015-04-01

    Observational studies have reported solar magnetic modulation of terrestrial lightning on a range of time scales, from days to decades. The proposed mechanism is two-step: lightning rates vary with galactic cosmic ray (GCR) flux incident on Earth, either via changes in atmospheric conductivity and/or direct triggering of lightning. GCR flux is, in turn, primarily controlled by the heliospheric magnetic field (HMF) intensity. Consequently, global changes in lightning rates are expected. This study instead considers HMF polarity, which doesn't greatly affect total GCR flux. Opposing HMF polarities are, however, associated with a 40 to 60% difference in observed UK lightning and thunder rates. As HMF polarity skews the terrestrial magnetosphere from its nominal position, this perturbs local ionospheric potential at high latitudes and local exposure to energetic charged particles from the magnetosphere. We speculate as to the mechanism(s) by which this may, in turn, redistribute the global location and/or intensity of thunderstorm activity.

  6. A study of the link between cosmic rays and clouds with a cloud chamber at the CERN PS

    E-print Network

    Fastrup, B; Lillestøl, Egil; Thorn, E; Bosteels, Michel; Gonidec, A; Harigel, G G; Kirkby, Jasper; Mele, S; Minginette, P; Nicquevert, Bertrand; Schinzel, D; Seidl, W; Grundsøe, P; Marsh, N D; Polny, J; Svensmark, H; Viisanen, Y; Kurvinen, K L; Orava, Risto; Hämeri, K; Kulmala, M; Laakso, I; Mäkelä, J M; O'Dowd, C D; Afrosimov, V; Basalaev, A; Panov, M; Laaksonen, B D; Joutsensaari, J; Ermakov, V; Makhmutov, V S; Maksumov, O; Pokrevsky, P; Stozhkov, Yu I; Svirzhevsky, N S; Carslaw, K; Yin, Y; Trautmann, T; Arnold, F; Wohlfrom, K H; Hagen, D; Schmitt, J; Whitefield, P; Aplin, K; Harrison, R G; Bingham, R; Close, Francis Edwin; Gibbins, C; Irving, A; Kellett, B; Lockwood, M; Petersen, D; Szymanski, W W; Wagner, P E; Vrtala, A; CERN. Geneva. SPS-PS Experiments Committee

    2000-01-01

    Recent satellite data have revealed a surprising correlation between galactic cosmic ray (GCR) intensity and the fraction of the Earth covered by clouds. If this correlation were to be established by a causal mechanism, it could provide a crucial step in understanding the long-sought mechanism connecting solar and climate variability. The Earth's climate seems to be remarkably sensitive to solar activity, but variations of the Sun's electromagnetic radiation appear to be too small to account for the observed climate variability. However, since the GCR intensity is strongly modulated by the solar wind, a GCR-cloud link may provide a sufficient amplifying mechanism. Moreover if this connection were to be confirmed, it could have profound consequences for our understanding of the solar contributions to the current global warming. The CLOUD (Cosmics Leaving OUtdoor Droplets) project proposes to test experimentally the existence a link between cosmic rays and cloud formation, and to understand the microphysical me...

  7. Cosmic ray fluctuations parameter as indicator of interplanetary "magnetic cork"

    NASA Astrophysics Data System (ADS)

    Kozlov, V. I.; Kozlov, V. V.

    2013-02-01

    It is established, that the main contribution into dynamics of galactic cosmic ray intensity fluctuations (GCR) in a vicinity of magnetic "cork" from a shock gives a nonrandom, non-Gauss component of GCR intensity. An occurrence of correlated fluctuations is caused by following circumstance: due to laws of conservation the probability that the cosmic ray particles reflected from a magnetic cork (in the expanding magnetic field) will undergo collimations, becomes considerable. The collimation will be manifested in focusing of particles into the anisotropic beams. In this case, observations should show "scintillations" of celestial sphere in cosmic rays i.e. the" HALO" effect. Similar scintillations are the indicator of interplanetary magnetic cork. The algorithm of detection of GCR scintillations is realized in real time using "Cyber-FORSHOCK" robotized system.

  8. 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.

  9. Updated Computational Model of Cosmic Rays Near Earth

    NASA Technical Reports Server (NTRS)

    ONeill, Patrick M.

    2006-01-01

    An updated computational model of the galactic-cosmic-ray (GCR) environment in the vicinity of the Earth, Earth s Moon, and Mars has been developed, and updated software has been developed to implement the updated model. This model accounts for solar modulation of the cosmic-ray contribution for each element from hydrogen through iron by computationally propagating the local interplanetary spectrum of each element through the heliosphere. The propagation is effected by solving the Fokker-Planck diffusion, convection, energy-loss boundary-value problem. The Advanced Composition Explorer NASA satellite has provided new data on GCR energy spectra. These new data were used to update the original model and greatly improve the accuracy of prediction of interplanetary GCR.

  10. 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.

  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. 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.

  13. 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

  14. 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.

  15. 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.

  16. Issues in deep space radiation protection.

    PubMed

    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. PMID:11669118

  17. 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.

  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. Sustained Interleukin-1? Exposure Modulates Multiple Steps in Glucocorticoid Receptor Signaling, Promoting Split-Resistance to the Transactivation of Prominent Anti-Inflammatory Genes by Glucocorticoids

    PubMed Central

    2015-01-01

    Clinical treatment with glucocorticoids (GC) can be complicated by cytokine-induced glucocorticoid low-responsiveness (GC-resistance, GCR), a condition associated with a homogeneous reduction in the expression of GC-receptor- (GR-) driven anti-inflammatory genes. However, GR level and phosphorylation changes modify the expression of individual GR-responsive genes differently. As sustained IL-1? exposure is key in the pathogenesis of several major diseases with prevalent GCR, we examined GR signaling and the mRNA expression of six GR-driven genes in cells cultured in IL-1? and afterwards challenged with GC. After a GC challenge, sustained IL-1? exposure reduced the cytoplasmic GR level, GRSer203 and GRSer211 phosphorylation, and GR nuclear translocation and led to selective GCR in the expression of the studied genes. Compared to GC alone, in a broad range of GC doses plus sustained IL-1?, FKBP51 mRNA expression was reduced by 1/3, TTP by 2/3, and IRF8 was completely knocked down. In contrast, high GC doses did not change the expression of GILZ and DUSP1, while IGFBP1 was increased by 5-fold. These effects were cytokine-selective, IL-1? dose- and IL-1R1-dependent. The integrated gain and loss of gene functions in the “split GCR” model may provide target cells with a survival advantage by conferring resistance to apoptosis, chemotherapy, and GC. PMID:25977599

  20. Mars Odyssey measurements of galactic cosmic rays and solar particles in Mars orbit, 2002–2008

    Microsoft Academic Search

    C. Zeitlin; W. Boynton; I. Mitrofanov; D. Hassler; W. Atwell; T. F. Cleghorn; F. A. Cucinotta; M. Dayeh; M. Desai; S. B. Guetersloh; K. Kozarev; K. T. Lee; L. Pinsky; P. Saganti; N. A. Schwadron; R. Turner

    2010-01-01

    The instrument payload aboard the 2001 Mars Odyssey orbiter includes several instruments that are sensitive to energetic charged particles from the galactic cosmic rays (GCR) and solar particle events (SPE). The Martian Radiation Environment Experiment (MARIE) was a dedicated energetic charged particle spectrometer, but it ceased functioning during the large solar storm of October\\/November 2003. Data from two other Odyssey

  1. Invited Editorial: Radiation exposures of aircrew in high altitude flight

    Microsoft Academic Search

    Lawrence W. Townsend

    2001-01-01

    Introduction Background radiation levels in the atmosphere vary in intensity with latitude, altitude and phase of the solar cycle. These background levels are generated primarily by galactic cosmic rays (GCR), consisting of energetic nuclei of all naturally occurring elements, interacting with atmospheric constituents, primarily through atomic and nuclear collisions. Cosmic rays were discovered in 1912, about the same time that

  2. 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 ? -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 ? -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.

  3. Transport signatures of electronic-nematic stripe phases This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-print Network

    Stroud, David

    . 2010 ApJ 711 744 (http://iopscience.iop.org/0004-637X/711/2/744) Download details: IP Address: 128 conditions with energetic electrons generated in the track of galactic cosmic-ray (GCR) particles to simulate

  4. Charge replacement in hybrid electrical energy storage systems

    Microsoft Academic Search

    Qing Xie; Yanzhi Wang; Massoud Pedram; Younghyun Kim; Donghwa Shin; Naehyuck Chang

    2012-01-01

    Hybrid electrical energy storage (HEES) systems are composed of multiple banks of heterogeneous electrical energy storage (EES) elements with distinctive properties. Charge replacement in a HEES system (i.e., dynamic assignment of load demands to EES banks) is one of the key operations in the system. This paper formally describes the global charge replacement (GCR) optimization problem and provides an algorithm

  5. Entrepreneurship and economic growth: Evidence from emerging and developed countries

    Microsoft Academic Search

    Dave Valliere; Rein Peterson

    2009-01-01

    This paper presents an extension to the economic growth model developed by Wong, Ho, and Autio (2005), to reflect differences in the economic effects of opportunity and necessity-based entrepreneurship in both emerging and developed countries. Data from 44 countries for the years 2004 and 2005, as collected by Global Entrepreneurship Monitor (GEM) research and Global Competitiveness Report (GCR) research, are

  6. The Astrophysical Journal, 697:20832088, 2009 June 1 doi:10.1088/0004-637X/697/2/2083 C 2009. The American Astronomical Society. All rights reserved. Printed in the U.S.A.

    E-print Network

    Fegley Jr., Bruce

    additional isotopic abundance ratios, calculated at the GCR source, reported from ACE/CRIS (see, e of Technology, Pasadena, CA 91125, USA 5 University of Minnesota, Minneapolis, MN 55455, USA 6 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA Received 2009 January 30; accepted

  7. The Conservation Equations for a Magnetically Confined Gas Core Nuclear Rocket

    Microsoft Academic Search

    Terry Kammash; David L. Galbraith

    1994-01-01

    A very promising propulsion scheme that could meet the objectives of the Space Exploration Initiative (SEI) of sending manned missions to Mars in the early part of the next century is the open-cycle Gas Core (GCR) Nuclear Rocket. Preliminary assessments of the performance of such advice indicate that specific impulses of several thousand seconds, and thrusts of hundreds of kilonewtons

  8. 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. [and others

    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.

  9. Cosmic radiation exposure of aircraft occupants on simulated high-latitude flights during solar proton events from 1 January 1986 through 1 January 2008

    Microsoft Academic Search

    Kyle Copeland; Herbert H. Sauer; Frances E. Duke; Wallace Friedberg

    2008-01-01

    From 1 January 1986 through 1 January 2008, GOES satellites recorded 170 solar proton events. For 169 of these events, we estimated effective and equivalent dose rates and doses of galactic cosmic radiation (GCR) and solar cosmic radiation (SCR), received by aircraft occupants on simulated high-latitude flights. Dose rate and dose estimates that follow are for altitudes 30, 40, 50,

  10. Impact of galactic cosmic radiation and CO2 on Phanerozoic climate change

    Microsoft Academic Search

    Klaus Wallmann

    2010-01-01

    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

  11. Cancer risk from exposure to galactic cosmic rays: implications for space exploration by human beings

    Microsoft Academic Search

    Marco Durante

    2006-01-01

    must be balanced with the cost, safety, and ethical concerns when deciding acceptable risks for astronauts. The main health concerns are exposure to galactic cosmic rays (GCR) and solar proton events, which lead to substantial, but poorly understood, risks of carcinogenesis and degenerative disease. 2,3 Spacefl ights in low Earth orbit, such as missions on a space shuttle and at

  12. 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

  13. 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.

  14. Glomerular glucocorticoid receptor expression is reduced in late responders to steroids in adult-onset minimal change disease

    Microsoft Academic Search

    Seung Hyeok Han; Sun Young Park; Jin-Ji Li; Seung Jae Kwak; Dong Sub Jung; Hoon Young Choi; Jung Eun Lee; Sung Jin Moon; Dong Ki Kim; Dae-Suk Han; Shin-Wook Kang

    Background. Compared to children, adult patients with minimal change disease (MCD) tend to have a slower response to steroids, but little is known about the factors influencing the steroid responsiveness in these patients. In this study, we investigated the difference in the expression of the glomerular glucocorticoid recep- tor (GCR) according to steroid responsiveness in 28 adult-onset MCD patients. Methods.

  15. Multifunctional Martian habitat composite material synthesized from in situ resources

    Microsoft Academic Search

    S. Sen; S. Carranza; S. Pillay

    2010-01-01

    The two primary requirements for a Martian habitat structure include effective radiation shielding against the Galactic Cosmic Ray (GCR) environment and sufficient structural and thermal integrity. To significantly reduce the cost associated with transportation of such materials and structures from earth, it is imperative that such building materials should be synthesized primarily from Martian in situ resources. This paper illustrates

  16. Evaluating shielding effectiveness for reducing space radiation cancer risks

    Microsoft Academic Search

    Francis A. Cucinotta; Myung-Hee Y. Kim; Lei Ren

    2006-01-01

    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 PDFs are used in significance tests for evaluating 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

  17. Biological Production of an Integrin ?v?3 Targeting Imaging Probe and Functional Verification

    PubMed Central

    Hwang, Mi-Hye; Kim, Jung Eun; Kim, Sang-Yeob; Kalimuthu, Senthilkumar; Jeong, Shin Young; Lee, Sang-Woo; Lee, Jaetae; Ahn, Byeong-Cheol

    2015-01-01

    The aim of the present study is to establish a bacterial clone capable of secreting an integrin ?v?3 targeting probe with bioluminescent and fluorescent activities, and to verify its specific targeting and optical activities using molecular imaging. A bacterial vector expressing a fusion of secretory Gaussia luciferase (sGluc), mCherry, and RGD (sGluc-mCherry-RGDX3; GCR), and a control vector expressing a fusion of secretory Gaussia luciferase and mCherry (sGluc-mCherry; GC) were constructed. The GCR and GC proteins were expressed in E. coli and secreted into the growth medium, which showed an approximately 10-fold higher luciferase activity than the bacterial lysate. Successful purification of GCR and GC was achieved using the 6X His-tag method. The GCR protein bound with higher affinity to U87MG cells than CHO cells in confocal microscopy and IVIS imaging, and also showed a high affinity for integrin ?v?3 expressing tumor xenografts in an in vivo animal model. An E. coli clone was established to secrete an integrin ?v?3 targeting imaging probe with bioluminescent and fluorescent activities. The probe was produced feasibly and at low cost, and has shown to be useful for the assessment of angiogenesis in vitro and in vivo. PMID:25654118

  18. Helium Production of Prompt Neutrinos on the Moon

    Microsoft Academic Search

    V. Andersen; T. L. Wilson; L. S. Pinksy

    2004-01-01

    The use of the moon as an astrophysical neutrino observatory is limited by the neutrino background produced by the interaction of galactic cosmic rays with the surface of the moon. We present the results of simulations of neutrino production by GCR Helium.

  19. Probing the heliosphere with the directional anisotropy of galactic cosmic-ray intensity

    NASA Astrophysics Data System (ADS)

    Munakata, Kazuoki

    2012-07-01

    Because of the large detector volume that can be deployed, ground-based detectors remain state-of-the-art instrumentation for measuring high-energy galactic cosmic-rays (GCRs). This paper demonstrates how useful information can be derived from observations of the directional anisotropy of the high-energy GCR intensity, introducing the most recent results obtained from the ground-based observations. The anisotropy observed with the global muon detector network (GMDN) provides us with a unique information of the spatial gradient of the GCR density which reflects the large-scale magnetic structure in the heliosphere. The solar cycle variation of the gradient gives an important information on the GCR transport in the heliosphere, while the short-term variation of the gradient enables us to deduce the large-scale geometry of the magnetic flux rope and the interplanetary coronal mass ejection (ICME). Real-time monitoring of the precursory anisotropy which has often been observed at the Earth preceding the arrival of the ICME accompanied by a strong shock may provide us with useful tools for forecasting the space weather with a long lead time. The solar cycle variation of the Sun's shadow observed in the TeV GCR intensity is also useful for probing the large-scale magnetic structure of the solar corona.

  20. Custom Device for Low-Dose Gamma Irradiation of Biological Samples 

    E-print Network

    Bi, Ruoming

    2012-02-14

    When astronauts travel in space, their primary health hazards are high-energy cosmic radiations from galactic cosmic rays (GCR). Most galactic cosmic rays have energies between 100 MeV and 10 GeV. For occupants inside of a space shuttle...

  1. The experimental and simulated LET spectrum and charge spectrum from CR39 detectors exposed to irons near CRaTER at BNL

    Microsoft Academic Search

    D. Zhou; E. Semones; S. Guetersloh; N. Zapp; M. Weyland; E. R. Benton

    2010-01-01

    Human will be sooner or later return to the moon and will eventually travel to the planets near Earth. Space radiation hazards are an important concern for human space flight in deep space where galactic cosmic rays (GCR) and solar energetic particles are dominated and radiation is much stronger than that in LEO (Low Earth Orbit) because in deep space

  2. Radiation shielding requirements for manned deep space missions

    Microsoft Academic Search

    R. T. Santoro; D. T. Ingersoll

    1991-01-01

    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

  3. Improvement of Risk Assessment from Space Radiation Exposure for Future Space Exploration Missions

    Microsoft Academic Search

    M. Y. Kim; A. L. Ponomarev; H. Nounu; H. Hussein; F. A. Cucinotta; William Atwell

    2007-01-01

    Protecting astronauts from space radiation exposure is an important challenge for mission design and operations for future exploration-class and long-duration missions. Crew members are exposed to sporadic solar particle events (SPEs) as well as to the continuous galactic cosmic radiation (GCR). If sufficient protection is not provided the radiation risk to crew members from SPEs could be significant. To improve

  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. IE 361 Exam 1 October 5, 2004 Prof. Vardeman

    E-print Network

    Vardeman, Stephen B.

    . One of their first steps toward process improvement was to do some gauge studies. An R&R study comparison of 38.46MSE = to the engineering specifications of 10± indicate about production-line measurement% confidence limits for the GCR (gauge capability ratio) here. (No need to simplify.) e) Suppose

  6. Biological production of an integrin ?v?3 targeting imaging probe and functional verification.

    PubMed

    Hwang, Mi-Hye; Kim, Jung Eun; Kim, Sang-Yeob; Kalimuthu, Senthilkumar; Jeong, Shin Young; Lee, Sang-Woo; Lee, Jaetae; Ahn, Byeong-Cheol

    2015-01-01

    The aim of the present study is to establish a bacterial clone capable of secreting an integrin ?v?3 targeting probe with bioluminescent and fluorescent activities, and to verify its specific targeting and optical activities using molecular imaging. A bacterial vector expressing a fusion of secretory Gaussia luciferase (sGluc), mCherry, and RGD (sGluc-mCherry-RGDX3; GCR), and a control vector expressing a fusion of secretory Gaussia luciferase and mCherry (sGluc-mCherry; GC) were constructed. The GCR and GC proteins were expressed in E. coli and secreted into the growth medium, which showed an approximately 10-fold higher luciferase activity than the bacterial lysate. Successful purification of GCR and GC was achieved using the 6X His-tag method. The GCR protein bound with higher affinity to U87MG cells than CHO cells in confocal microscopy and IVIS imaging, and also showed a high affinity for integrin ?v?3 expressing tumor xenografts in an in vivo animal model. An E. coli clone was established to secrete an integrin ?v?3 targeting imaging probe with bioluminescent and fluorescent activities. The probe was produced feasibly and at low cost, and has shown to be useful for the assessment of angiogenesis in vitro and in vivo. PMID:25654118

  7. Possible satellite perspective effects on the reported correlations between solar activity and clouds

    E-print Network

    and clouds E. Palle´ Big Bear Solar Observatory, New Jersey Institute of Technology, Big Bear City February 2005. [1] Recently some correlations between low cloud cover and solar activity have been reported in the literature. In this paper we show how the flux of GCR is found to correlate positively with the low clouds

  8. Predictions of the electrical conductivity and charging of the cloud particles in Jupiter's atmosphere

    Microsoft Academic Search

    R. C. Whitten; W. J. Borucki; K. O'Brien; S. N. Tripathi

    2008-01-01

    The electrical conductivity and electrical charge on cloud particles (composed of ammonia, ammonium hydrosulfide, and water) in the atmosphere of Jupiter are computed for pressures between 5.5 and 0.1 bars. The source of ionization is galactic cosmic rays (GCR). The distribution of charge among the various reservoirs is a function of altitude and the total area of the aerosol particles.

  9. Track structure and radiation transport model for space radiobiology studies

    Microsoft Academic Search

    F. A Cucinotta; J. W Wilson; R Katz; W Atwell; G. D Badhwar; M. R Shavers

    1996-01-01

    Radiobiology experiments performed in space are deemed necessary for validation of risk-assessment methods. The understanding of space radiobiology experiments must combine knowledge of the space radiation environment, radiation transport, and models of biological response. The heavy ion transport code HZETRN has recently been combined with improved models of the galactic cosmic rays (GCR) and extensive comparisons made to measurements on

  10. Thursday, March 26, 2009 POSTER SESSION II: PURSUING LUNAR EXPLORATION

    E-print Network

    Rathbun, Julie A.

    Exhibit Area Wilson T. L. Lee K. T. Photon Luminescence of the Moon [#1918] The space-radiation-induced photon luminescence existing on the Moon is derived from SEP and GCR sources. Its spectrum is present: Comparison of Shackleton Base Scenario and Sortie Surface Scenarios at the Nectaris Basin, Marius Hills

  11. Managing Technical Risk: Understanding Private Sector

    E-print Network

    , Technology-based Projects ADADVANCEDANCED TECHNOLOGY PRTECHNOLOGY PROGRAMOGRAM NIST GCR 00-787 National 00-787 Managing Technical Risk Understanding Private Sector Decision Making on Early Stage Technology-based Entrepreneurship Center, Sloan School of Management Massachusetts Institute of Technology Michael J. Roberts

  12. A study of the link between cosmic rays and clouds with a cloud chamber at the CERN PS

    Microsoft Academic Search

    E. Pedersen; E. Lillestol; E. Thorn; M. Bosteels; A. Gonidec; G. Harigel; J. Kirkby; S. Mele; B. Nicquevert; D. Schinzel; W. Seidl; P. Grundsøe; N. Marsh; J. Polny; H. Svensmark; Y. Viisanen; K. Kurvinen; R. Orava; K. Hameri; M. Kulmala; L. Laakso; J. M. Makela; C. D. O'Dowd

    2001-01-01

    Recent satellite data have revealed a surprising correlation between galactic cosmic ray (GCR) intensity and the fraction of the Earth covered by clouds. If this correlation were to be established by a causal mechanism, it could provide a crucial step in understanding the long-sought mechanism connecting solar and climate variability. The Earth's climate seems to be remarkably sensitive to solar

  13. 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.

  14. Results from the Martian Radiation Environment Experiment

    Microsoft Academic Search

    C. Zeitlin; T. F. Cleghorn; F. A. Cucinotta; P. Saganti

    2003-01-01

    Ionizing radiation in space presents a potentially serious health hazard to astronauts on long-duration missions outside the geomagnetosphere. As a precursor to possible human exploration, the Martian Radiation Environment Experiment, MARIE, is returning the first detailed radiation data from Mars. MARIE is designed to measure the nearly constant flux of energetic Galactic Cosmic Rays (GCR) and intermittent Solar Particle Events

  15. The Martian Radiation Environment Experiment: Overview and First Results

    Microsoft Academic Search

    C. Zeitlin; F. A. Cucinotta; T. F. Cleghorn; P. Saganti; L. S. Pinsky; K. T. Lee; W. A. Atwell

    2002-01-01

    The Martian Radiation Environment Experiment (MARIE) is designed to measure charged particle radiation in Mars orbit as a precursor to possible human exploration. Charged nuclear particles originating from galactic sources (the Galactic Cosmic Rays, or GCR) are known to pose a health risk from chronic exposures, which will be inevitable during transit and during prolonged stays on the Martian surface.

  16. 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.

  17. Impact of atmospheric CO2 and galactic cosmic radiation on Phanerozoic climate change and the marine ?18O 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, ?18O), marine carbonates (Sr/Ca, 87Sr/86Sr, ?13C, ?18O), atmospheric CO2 and surface temperature. The marine carbonate records (Sr/Ca, 87Sr/86Sr, ?13C) 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 ?18O 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 ?18O 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 ?18O values observed in the geological record are caused by low pH values in surface waters rather than cold surface conditions.

  18. Sponsorship Package International Conference on

    E-print Network

    Tucci, Sara

    Sponsorship Package International Conference on Distributed Event-Based Systems Rome, Italy, July 2nd-4th, 2008 http://debs08.dis.uniroma1.it/ DEBS20082nd International Conference on Distributed Event-Based Systems 1 #12;DEBS20082nd International Conference on Distributed Event-Based Systems Conference Overview

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. On manifestation of the solar wind turbulence in fluctuations of the galactic cosmic ray intensity

    NASA Astrophysics Data System (ADS)

    Alania, Michael V.; Modzelewska, Renata; Wawrzynczak, Anna

    2010-05-01

    We study a relationship between the interplanetary magnetic field (IMF) and the solar wind speed (SWS) turbulence measured in the interplanetary space (in situ) and the galactic cosmic ray (GCR) intensity fluctuations measured by neutron monitors (at earth surface) for different time scales of ranges 5 - 60 minutes and 1 - 24 hours. We calculate the Probability Distribution Functions (PDF) of differences ?B?, ?V ? , and ?I? of the time series B(ti) of the IMF strength , V (ti) of the SWS, and I(ti) of the GCR intensity, respectively, as ?B? = B(t + ?) - B(t), ?V ? = V (t + ?) - V (t) and ?I? = I(t + ?) - I(t) over varying time scales ?. Then, we find correlation coefficients among them and characteristic time scale ?0 for which (? > ?0) the asymmetry (skewness) and kurtosis of PDFs are minimum, and in good approximation PDFs have Gaussian distributions. We show that the asymmetry and inhomogeneities of the IMF and solar wind turbulence generally are manifested for time scale ? < 1 day, while for the GCR fluctuations for ? ?0, and PDF has a Gaussian distribution, the IMF turbulence is characterized by the power spectral density (PSD), with parameters p and ? (PSD = Pf-? , where P is power and f is a frequency). In this case diffusion of GCR particles could be described by the quasi linear theory (QLT), and diffusion coefficient K is proportional to the rigidity R, as K ~ R2-?; correspondingly, the exponent ? of the rigidity R spectrum (?D(R)-D(R) ? R-?) of the GCR intensity variations (e.g. of Forbush decrease) of the energy to which neutron monitors and muon telescopes (for rigidity > 5 - 10 GV) respond, is determined by the exponent ? of PSD of the IMF turbulence.

  4. Stochastic differences of the solar cycles according to monitoring cosmogenic radionuclides in fresh-fallen meteorites

    NASA Astrophysics Data System (ADS)

    Alexeev, Victor; Ustinova, Galina; Povinec, Pavel; Laubenstein, Matthias

    Cosmogenic radionuclides with different T_1/2, which are observed in meteorites, are natural detectors of cosmic rays along the meteorite orbits during ~1.5 T_1/2 of the radionuclides before the meteorite fall onto the Earth. The investigation of radionuclides with different T_1/2 in the chondrites with various dates of fall, which have various extension and inclination of orbits, provides us with such long sequences of homogeneous data on variation of the GCR intensity and integral gradients (E>100 MeV) in the 3D heliosphere [1]. The long sequences of homogeneous data on the GCR intensity in the stratosphere are used for evaluation of the gradients [2]. Nowadays, such a sequence of certain homogeneous data on the GCR intensity and gradients in the inner heliosphere covers ~5 solar cycles [3]. This smoothes, to a considerable extent, both the temporal and spatial GCR variations revealing the most important general regularities, namely: the dependence of the GCR gradients in the inner heliosphere (at 2-4 AU from the Sun) on the phase of the solar cycles and the constancy of the mechanism of the solar modulation of GCRs, at least over the last ~1 Ma. The most striking effect - which due to the monitoring became evident - is a stochastic difference of the solar cycles in addition to their determination by the solar activity. A rigorous analysis of correlations between the distribution and variations of GCRs and various indexes of the solar activity, as well as the strength of interplanetary magnetic fields and the title of the heliospheric current sheet in the three-dimensional heliosphere, have been carry out. As a whole, it testifies to the approximately positive correlations of all the parameters. However, the analysis has revealed some dependence of the depth of GCR modulation in the heliosphere on the character of the solar magnetic fields inversion during the maximum phases of the solar cycles, namely, on N-S asymmetry of emergence of active areas, on difference of their beginning and developing, on different lasting of the inversion periods, etc. For instance, a combined operation of the effects resulted in the deepest minimum of the GCR intensity in stratosphere in 1990-1991 and the highest GCR gradients for the 22nd solar cycle. Some peculiarities of the 23 and 24 solar cycles are considered due to study of radionuclides in the recently fallen Kosice and Chelyabinsk chondrites. The observed features of the GCR modulation during the last solar cycles could be conditioned by some disturbances of processes in the convective zone of the Sun at the change of the current secular cycle. [1] Lavrukhina A K and Ustinova G K 1990 Meteorites as Probes of Cosmic Ray Variations (Moscow: Nauka) [2] Stozhkov Yu I et al. 2009 Adv. Space Res. 44 1124-37 [3] Alexeev V A et al. 2013 Journal of Physics: Conf. Ser. 409 012146

  5. 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

  6. 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.

  7. 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 ?Gy/h and the dose equivalent rates are 24.6-36.7 ?Sv/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.

  8. 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.

  9. An analytical model for the prediction of a micro-dosimeter response function

    NASA Astrophysics Data System (ADS)

    Badavi, Francis; Michael, Michael; Wilson, John W.

    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 (? rays) events. At any designated (ray traced) target point within the vehicle, the model as input accepts the differential flux spectrum of Galactic Cosmic Rays (GCR) and/or trapped protons at LEO. 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's GCR model (2004), covering charge particles in the 1?Z?28 range. O'Neill's free space GCR model is coupled with the Langley Research Center (LaRC) cutoff model with angular dependency compensation to compute the transmission coefficient at 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 56, 51, 110 and 114 flights are accomplished by using the most recent version (2005) of LaRC's deterministic ionized particle transport code High charge (Z) and Energy TRaNsport (HZETRN). Herein, 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 in the y domain between STS 56, 51, 110 and 114 TEPC measured data and current calculations indicates that there still exists an underestimation by the simulations (model) at low to mid range y values. This underestimation is argued to be partly related the exclusion of the secondary pion and kaon particle production from the current version of HZETRN.

  10. 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.

  11. A Saccharomyces cerevisiae RNase H2 Interaction Network Functions To Suppress Genome Instability

    PubMed Central

    Allen-Soltero, Stephanie; Martinez, Sandra L.; Putnam, Christopher D.

    2014-01-01

    Errors during DNA replication are one likely cause of gross chromosomal rearrangements (GCRs). Here, we analyze the role of RNase H2, which functions to process Okazaki fragments, degrade transcription intermediates, and repair misincorporated ribonucleotides, in preventing genome instability. The results demonstrate that rnh203 mutations result in a weak mutator phenotype and cause growth defects and synergistic increases in GCR rates when combined with mutations affecting other DNA metabolism pathways, including homologous recombination (HR), sister chromatid HR, resolution of branched HR intermediates, postreplication repair, sumoylation in response to DNA damage, and chromatin assembly. In some cases, a mutation in RAD51 or TOP1 suppressed the increased GCR rates and/or the growth defects of rnh203? double mutants. This analysis suggests that cells with RNase H2 defects have increased levels of DNA damage and depend on other pathways of DNA metabolism to overcome the deleterious effects of this DNA damage. PMID:24550002

  12. 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.

  13. 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.

  14. Cermet coating tribological behavior in high temperature helium

    SciTech Connect

    CACHON, Lionel; ALBALADEJO, Serge; TARAUD, Pascal; LAFFONT, G. [Centre de Cadarache, 13108 Saint-Paul-lez-Durance (France)

    2006-07-01

    As the CEA is highly involved in the Generation IV Forum, a comprehensive research and development program has been conducted for several years, in order to establish the feasibility of Gas Cooled Reactor (GCR) technology projects using helium as a cooling fluid. Within this framework, a tribology program was launched in order to select and qualify coatings and materials, and to provide recommendations for the sliding components operating in GCRs. The purpose of this paper is to describe the CEA Helium tribology study on several GCR components (thermal barriers, control rod drive mechanisms, reactor internals, ..) requiring protection against wear and bonding. Tests in helium atmosphere are necessary to be fully representative of tribological environments and to assess the material or coating candidates which can provide a reliable answer to these situations. This paper focuses on the tribology tests performed on CERMET (Cr{sub 3}C-2- NiCr) coatings within a temperature range of between 800 and 1000 deg C.

  15. Variations of dose rate observed by MSL/RAD in transit to Mars

    E-print Network

    Guo, Jingnan; Wimmer-Schweingruber, Robert F; Hassler, Donald M; Posner, Arik; Heber, Bernd; Köhler, Jan; Rafkin, Scot; Ehresmann, Bent; Appel, Jan K; Böhm, Eckart; Böttcher, Stephan; Burmeister, Sönke; Brinza, David E; Lohf, Henning; Martin, Cesar; Reitz, Günther

    2015-01-01

    Aims: To predict the cruise radiation environment related to future human missions to Mars, the correlation between solar modulation potential and the dose rate measured by the Radiation Assessment Detector (RAD) has been analyzed and empirical models have been employed to quantify this correlation. Methods: The instrument RAD, onboard Mars Science Laboratory's (MSL) rover Curiosity, measures a broad spectrum of energetic particles along with the radiation dose rate during the 253-day cruise phase as well as on the surface of Mars. With these first ever measurements inside a spacecraft from Earth to Mars, RAD observed the impulsive enhancement of dose rate during solar particle events as well as a gradual evolution of the galactic cosmic ray (GCR) induced radiation dose rate due to the modulation of the primary GCR flux by the solar magnetic field, which correlates with long-term solar activities and heliospheric rotation. Results: We analyzed the dependence of the dose rate measured by RAD on solar modulatio...

  16. Quiet-Time Spectra and Abundances of Energetic Particles During the 1996 Solar Minimum

    NASA Technical Reports Server (NTRS)

    Reames, Donald V.

    1999-01-01

    We report the energy spectra and abundances of ions with atomic number, Z, in the interval Z is greater than or equal to 2 and Z is less than or equal to 36 and energies approximately 3-20 MeV/amu for solar and interplanetary quiet periods between 1994 November and 1998 April as measured by the large-geometry Low Energy Matrix Telescope (LEMT) telescope on the Wind spacecraft near Earth. The energy spectra show the presence of galactic (GCR) and "anomalous" cosmic ray (ACR) components, depending on the element. ACR components are reported for Mg and Si for the first time at 1 AU and the previous observation of S and Ar is confirmed. However, only GCR components are clearly apparent for the elements Ca, Ti, Cr, Fe, as well as for C. New limits are placed on a possible ACR contribution for other elements, including Kr.

  17. Quiet-Time Spectra and Abundances of Energetic Particles During the 1996 Solar Minimum

    NASA Technical Reports Server (NTRS)

    Reames, Donald V.

    1998-01-01

    This report concerns the energy spectra and abundances of ions with atomic number, Z, in the interval 2 greater than or equal to Z and Z less than or equal to 36 and energies approximately 3-20 MeV/amu for solar and interplanetary quiet periods between November 1994 and April 1998 as measured by the large-geometry LEMT telescope on the Wind spacecraft near Earth. The energy spectra show the presence of galactic (GCR) and 'anomalous' cosmic ray (ACR) components, depending on the element. ACR components are reported for Mg and Si for the first time at 1 AU and the previous observation of S and Ar is confirmed. However, only GCR components are clearly apparent for the elements Ca, Ti, Cr, Fe, as well as for C. New limits are placed on a possible ACR contribution for other elements, including Kr.

  18. 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.

  19. 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.

  20. Suppression of gross chromosomal rearrangements by a new alternative replication factor C complex

    SciTech Connect

    Banerjee, Soma; Sikdar, Nilabja [Genome Instability Section, Genetics and Molecular Biology Branch, National Human Genome Research Institute, National Institutes of Health, 49 Convent Drive, Room 4A22, Bethesda, MD 20892 (United States); Myung, Kyungjae [Genome Instability Section, Genetics and Molecular Biology Branch, National Human Genome Research Institute, National Institutes of Health, 49 Convent Drive, Room 4A22, Bethesda, MD 20892 (United States)], E-mail: kmyung@nhgri.nih.gov

    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.

  1. 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%.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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).

  8. Modeling the variations of Dose Rate measured by RAD during the first MSL Martian year: 2012-2014

    E-print Network

    Guo, Jingnan; Wimmer-Schweingruber, Robert F; Rafkin, Scot; Hassler, Donald M; Posner, Arik; Heber, Bernd; Koehler, Jan; Ehresmann, Bent; Appel, Jan K; Boehm, Eckart; Boettcher, Stephan; Burmeister, Soenke; Brinza, David E; Lohf, Henning; Martin, Cesar; Kahanpaeae, H; Reitz, Guenther

    2015-01-01

    The Radiation Assessment Detector (RAD), on board Mars Science Laboratory's (MSL) rover Curiosity, measures the {energy spectra} of both energetic charged and neutral particles along with the radiation dose rate at the surface of Mars. With these first-ever measurements on the Martian surface, RAD observed several effects influencing the galactic cosmic ray (GCR) induced surface radiation dose concurrently: [a] short-term diurnal variations of the Martian atmospheric pressure caused by daily thermal tides, [b] long-term seasonal pressure changes in the Martian atmosphere, and [c] the modulation of the primary GCR flux by the heliospheric magnetic field, which correlates with long-term solar activity and the rotation of the Sun. The RAD surface dose measurements, along with the surface pressure data and the solar modulation factor, are analysed and fitted to empirical models which quantitatively demonstrate} how the long-term influences ([b] and [c]) are related to the measured dose rates. {Correspondingly we ...

  9. 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.

  10. Application of real-time radiation dosimetry using a new silicon LET sensor

    NASA Technical Reports Server (NTRS)

    Doke, T.; Hayashi, T.; Kikuchi, J.; Nagaoka, S.; Nakano, T.; Sakaguchi, T.; Terasawa, K.; Badhwar, G. D.

    1999-01-01

    A new type of real-time radiation monitoring device, RRMD-III, consisting of three double-sided silicon strip detectors (DSSDs), has been developed and tested on-board the Space Shuttle mission STS-84. The test succeeded in measuring the linear energy transfer (LET) distribution over the range of 0.2 keV/micrometer to 600 keV/micrometer for 178 h. The Shuttle cruised at an altitude of 300 to 400 km and an inclination angle of 51.6 degrees for 221.3 h, which is equivalent to the International Space Station orbit. The LET distribution obtained for particles was investigated by separating it into galactic cosmic ray (GCR) particles and trapped particles in the South Atlantic Anomaly (SAA) region. The result shows that the contribution in dose-equivalent due to GCR particles is almost equal to that from trapped particles. The total absorbed dose rate during the mission was 0.611 mGy/day; the effective quality factor, 1.64; and the dose equivalent rate, 0.998 mSv/day. The average absorbed dose rates are 0.158 mGy/min for GCR particles and 3.67 mGy/min for trapped particles. The effective quality factors are 2.48 for GCR particles and 1.19 for trapped particles. The absorbed doses obtained by the RRMD-III and a conventional method using TLD (Mg(2)SiO(4)), which was placed around the RRMD-III were compared. It was found that the TLDs showed a lower efficiency, just 58% of absorbed dose registered by the RRMD-III.

  11. 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.

  12. Optimized Shielding for Space Radiation Protection

    Microsoft Academic Search

    J. W. Wilson; F. A. Cucinotta; M.-H. Y. Kim; W. Schimmerling

    2000-01-01

    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

  13. Radiation risk predictions for Space Station Freedom orbits

    NASA Astrophysics Data System (ADS)

    Cucinotta, Francis A.; Atwell, William; Weyland, Mark; Hardy, Alva C.; Wilson, John W.; Townsend, Lawrence W.; Shinn, Judy L.; Katz, Robert

    1991-06-01

    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.

  14. Radiation climate map for analyzing risks to astronauts on the mars surface from galactic cosmic rays

    Microsoft Academic Search

    Premkumar B. Saganti; Francis A. Cucinotta; John W. Wilson; Lisa C. Simonsen; Cary Zeitlin

    2004-01-01

    The potential risks for late effects including cancer, cataracts, and neurological disorders due to exposures to the galactic\\u000a cosmic rays (GCR) is a large concern for the human exploration of Mars. Physical models are needed to project the radiation\\u000a exposures to be received by astronauts in transit to Mars and on the Mars surface, including the understanding of the modification

  15. Smc5–Smc6 complex suppresses gross chromosomal rearrangements mediated by break-induced replications

    Microsoft Academic Search

    Ji-Young Hwang; Stephanie Smith; Audrey Ceschia; Jordi Torres-Rosell; Luis Aragon; Kyungjae Myung

    2008-01-01

    Translocations in chromosomes alter genetic information. Although the frequent translocations observed in many tumors suggest the altered genetic information by translocation could promote tumorigenesis, the mechanisms for how translocations are suppressed and produced are poorly understood. The smc6–9 mutation increased the translocation class gross chromosomal rearrangement (GCR). Translocations produced in the smc6–9 strain are unique because they are non-reciprocal and

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Predictions of the electrical conductivity and charging of the aerosols in Titan's atmosphere

    Microsoft Academic Search

    W. J. Borucki; R. C. Whitten; E. L. O. Bakes; E. Barth; S. Tripathi

    2006-01-01

    The electrical conductivity and electrical charge on the aerosols in atmosphere of Titan are computed for altitudes between 0 and 400 km. Ionization of methane and nitrogen due to galactic cosmic rays (GCR) is important at night where these ions are converted to ion clusters such as CH+5CH4, C7H+7, C4H+7, and H4C7N+. The ubiquitous aerosols observed also play an important

  1. Anisotropy Observed at the Brazilian Southern Space Observatory by the Multidirectional Muon Detector MMD

    Microsoft Academic Search

    Níkolas Kemmerich; Alisson Dal Lago; Nelson Jorge Schuch; Marlos da Silva; Lucas Ramos Vieira; Carlos Roberto Braga; Marcos Vinicius Dias Silveira; Tardelli Ronan Coelho Stekel

    2010-01-01

    Galactic Cosmic Rays (GCR) (about 50 GeV) are observed by ground-level detectors. They suf-fer modulation effects due to interplanetary disturbances such as ICMEs and its correspondent structures, i.e., interplanetary shock waves and magnetic clouds which can cause geomagnetic storms in the Earth's magnetosphere. Forbush Decrease (FD) is an intense decrease of cosmic rays formed behind the shock accompanied by an

  2. Turbo-EEPRML: An EEPR4 channel with an error-correcting post-processor designed for 16\\/17 rate quasi-MTR code

    Microsoft Academic Search

    Takushi Nishiya; Kyoko Tsukano; T. Hirai; Takashi Nara; Seiichi Mita

    1998-01-01

    An EEPRML channel with a post processor has been developed for compensating for the degradation in performance due to noise correlation. This Turbo-EEPRML is designed for 16\\/17 rate quasi-MTR (QMTR) code. The proposed method has high performance and simple circuitry. Simulation showed that Turbo-EEPRML has a 2.0-2.5 dB coding gain over a conventional EPRML channel for 16\\/17 GCR code

  3. 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.

  4. Record Intensities of Galactic Cosmic Rays in 2009

    NASA Astrophysics Data System (ADS)

    Mewaldt, R. A.; Davis, Andrew; Lave, Kelly; Leske, Richard; Wiedenbeck, Mark; Binns, Walter; Cummings, A. C.; Israel, Martin; Stone, E. C.; von Rosenvinge, Tycho

    Data from the Advanced Composition Explorer (ACE) show that in late 2009 the galactic cosmic ray (GCR) intensity at 200 MeV/nuc (near the peak in the spectrum at 1 AU) reached the highest intensities of the space era. During mid-2007 GCR intensities had apparently leveled off at intensities comparable to those measured in the 1976-77 and 1997-1998 solar minima, and the onset of new solar activity was expected in 2008. Instead, solar-minimum conditions continued, and the GCR intensity began to increase again in early 2008. By the end of 2009 the 200 MeV/nuc intensities of the major species from C to Fe were all about 20 percent above those in the 1997-1998 solar minimum. Comparisons with earlier spacecraft data show conclusively that the GCR intensities late 2009 were the highest of the space era. However, viewed in the context of the long-term Be-10 record, the space era has experienced a below-average cosmic-ray intensity. The record-setting intensity levels are likely due to a combination of factors that include the weakened interplanetary magnetic field strength, the reduced solar wind speed and dynamic pressure, and the extended solar minimum conditions. In addition, during alternate solar minima, including the present one, the drift pattern of cosmic rays in the heliosphere is sensitive to the tilt of the interplanetary magnetic current sheet, which gradually declined during 2008-2009, eventually reaching 10 degrees. This paper will compare the 2009 cosmic ray intensities with those from the past 50 years and with the long-term archival record, and discuss the role of the various solar-wind parameters in modulating the near-Earth cosmic ray intensity.

  5. 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

  6. 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. [Infrared Processing and Analysis Center, California Institute of Technology, Mail Code 220-6, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Cotera, A. [SETI Institute, 515 North Whisman Road, Mountain View, CA 94043 (United States); Dong, H.; Wang, Q. D. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Morris, M. R. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Lang, C., E-mail: mauerhan@ipac.caltech.edu [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52245 (United States)

    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.

  7. The Predicted G-Protein-Coupled Receptor GPR1 Is Required for Female Sexual Development in the Multicellular Fungus Neurospora crassa

    Microsoft Academic Search

    Svetlana Krystofova; Katherine A. Borkovich

    2006-01-01

    G-protein-coupled receptors (GPCRs) control important aspects of asexual and sexual development in eukaryotic organisms. We have identified a predicted GPCR in the filamentous fungus Neurospora crassa with similarity to cyclic AMP-receptor like GPCRs from Dictyostelium discoideum and GCR1 from Arabidopsis thaliana. Expression of gpr-1 is highest in female reproductive structures, and deletion of gpr-1 leads to defects during sexual development.

  8. The Martian Radiation Environment Experiment -- Results and Status

    Microsoft Academic Search

    C. Zeitlin; T. F. Cleghorn; F. A. Cucinotta; P. Saganti; V. Andersen; K. T. Lee; L. S. Pinsky; W. Atwell; R. Turner

    2004-01-01

    Ionizing radiation in space presents a potentially serious health hazard to astronauts on long-duration missions. Missions that take humans outside the geomagnetosphere (which provides significant shielding for crews in low-Earth orbit) are of particular concern. A mission to Mars would expose a crew to a substantial radiation dose from high-energy heavy ions in the Galactic Cosmic Radiation (GCR). Though not

  9. The 22-Year Hale Cycle in Cosmic Ray Flux - Evidence for Direct Heliospheric Modulation

    NASA Astrophysics Data System (ADS)

    Thomas, S. R.; Owens, M. J.; Lockwood, M.

    2014-01-01

    The ability to predict times of greater galactic cosmic ray (GCR) fluxes is important for reducing the hazards caused by these particles to satellite communications, aviation, or astronauts. The 11-year solar-cycle variation in cosmic rays is highly correlated with the strength of the heliospheric magnetic field. Differences in GCR flux during alternate solar cycles yield a 22-year cycle, known as the Hale Cycle, which is thought to be due to different particle drift patterns when the northern solar pole has predominantly positive (denoted as qA>0 cycle) or negative ( qA<0) polarities. This results in the onset of the peak cosmic-ray flux at Earth occurring earlier during qA>0 cycles than for qA<0 cycles, which in turn causes the peak to be more dome-shaped for qA>0 and more sharply peaked for qA<0. In this study, we demonstrate that properties of the large-scale heliospheric magnetic field are different during the declining phase of the qA<0 and qA>0 solar cycles, when the difference in GCR flux is most apparent. This suggests that particle drifts may not be the sole mechanism responsible for the Hale Cycle in GCR flux at Earth. However, we also demonstrate that these polarity-dependent heliospheric differences are evident during the space-age but are much less clear in earlier data: using geomagnetic reconstructions, we show that for the period of 1905 - 1965, alternate polarities do not give as significant a difference during the declining phase of the solar cycle. Thus we suggest that the 22-year cycle in cosmic-ray flux is at least partly the result of direct modulation by the heliospheric magnetic field and that this effect may be primarily limited to the grand solar maximum of the space-age.

  10. Monte Carlo transport model comparison with 1A GeV accelerated iron experiment: heavy-ion shielding evaluation of NASA space flight-crew foodstuff

    NASA Technical Reports Server (NTRS)

    Stephens, D. L. Jr; Townsend, L. W.; Miller, J.; Zeitlin, C.; Heilbronn, L.

    2002-01-01

    Deep-space manned flight as a reality depends on a viable solution to the radiation problem. Both acute and chronic radiation health threats are known to exist, with solar particle events as an example of the former and galactic cosmic rays (GCR) of the latter. In this experiment Iron ions of 1A GeV are used to simulate GCR and to determine the secondary radiation field created as the GCR-like particles interact with a thick target. A NASA prepared food pantry locker was subjected to the iron beam and the secondary fluence recorded. A modified version of the Monte Carlo heavy ion transport code developed by Zeitlin at LBNL is compared with experimental fluence. The foodstuff is modeled as mixed nuts as defined by the 71st edition of the Chemical Rubber Company (CRC) Handbook of Physics and Chemistry. The results indicate a good agreement between the experimental data and the model. The agreement between model and experiment is determined using a linear fit to ordered pairs of data. The intercept is forced to zero. The slope fit is 0.825 and the R2 value is 0.429 over the resolved fluence region. The removal of an outlier, Z=14, gives values of 0.888 and 0.705 for slope and R2 respectively. c2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

  11. Optimizing Reduction in Basal Hyperglucagonaemia to Repair Defective Glucagon Counterregulation in Insulin Deficiency

    PubMed Central

    Farhy, Leon S.; McCall, Anthony L.

    2012-01-01

    In health, the pancreatic islet cells work as a network with highly coordinated signals over time to balance glycaemia within a narrow range. In type 1 diabetes (T1DM), with autoimmune destruction of the ?-cells, lack of insulin is considered the primary abnormality and is the primary therapy target. However, replacing insulin alone does not achieve adequate glucose control and recent studies have focused on controlling the endogenous glucagon release as well. In T1DM, glucagon secretion is disordered but not absolutely deficient; it may be excessive postprandially yet it is characteristically insufficient and delayed in response to hypoglycaemia. We review our system-level analysis of the pancreatic endocrine network mechanisms of glucagon counterregulation (GCR) and their dysregulation in T1DM and focus on possible use of ?-cell inhibitors (ACI) to manipulate the glucagon axis to repair the defective GCR. Our results indicate that the GCR abnormalities are of “network origin”. The lack of ?-cell signalling is the primary deficiency which contributes to two separate network abnormalities: (i) absence of a ?-cell switch-off trigger and (ii) increase intraislet basal glucagon. A strategy to repair these abnormalities with ACI is proposed which could achieve better control of glycaemia with reduced hypoglycaemia risk. PMID:21824267

  12. Galactic-cosmic-ray-produced 3He in a ferromanganese crust: any supernova 60Fe excess on earth?

    PubMed

    Basu, S; Stuart, F M; Schnabel, C; Klemm, V

    2007-04-01

    An excess of 60Fe in 2.4-3.2 x 10(6) year old ferromanganese crust (237 KD) from the deep Pacific Ocean has been considered as evidence for the delivery of debris from a nearby supernova explosion to Earth. Extremely high ;{3}He/;{4}He (up to 6.12 x 10(-3)) and 3He concentrations (up to 8 x 10(9) atoms/g) measured in 237 KD cannot be supernova-derived. The helium is produced by galactic cosmic rays (GCR) and delivered in micrometeorites that have survived atmospheric entry to be trapped by the crust. 60Fe is produced by GCR reactions on Ni in extraterrestrial material. The maximum (3)He/(60)Fe of 237 KD (80-850) is comparable to the GCR (3)He/(60)Fe production ratio (400-500) predicted for Ni-bearing minerals in iron meteorites. The excess 60Fe can be plausibly explained by the presence of micrometeorites trapped by the crust, rather than injection from a supernova source. PMID:17501264

  13. A model for predicting the radiation exposure for mission planning aboard the international space station

    NASA Astrophysics Data System (ADS)

    El-Jaby, Samy; Lewis, Brent J.; Tomi, Leena

    2014-04-01

    The International Space Station Cosmic Radiation Exposure Model (ISSCREM) has been developed as a possible tool for use in radiation mission planning as based on operational data collected with a tissue equivalent proportional counter (TEPC) aboard the ISS since 2000. It is able to reproduce the observed trapped radiation and galactic cosmic radiation (GCR) contributions to the total dose equivalent to within ±20% and ±10%, respectively, as would be measured by the onboard TEPC at the Zvezda Service Module panel 327 (SM-327). Furthermore, when these contributions are combined, the total dose equivalent that would be measured at this location is estimated to within ±10%. The models incorporated into ISSCREM correlate the GCR dose equivalent rate to the cutoff rigidity magnetic shielding parameter and the trapped radiation dose equivalent rate to atmospheric density inside the South Atlantic Anomaly. The GCR dose equivalent rate is found to vary minimally with altitude and TEPC module location however, due to the statistics and data available, the trapped radiation model could only be developed for the TEPC located at SM-327. Evidence of the variation in trapped radiation dose with detector orientation and the East-West asymmetry were observed at this location.

  14. Initiation-promotion model of tumor prevalence in mice from space radiation exposures.

    PubMed

    Cucinotta, F A; Wilson, J W

    1995-08-01

    Exposures in space consist of low-level background components from galactic cosmic rays (GCR), occasional intense-energetic solar-particle events, periodic passes through geomagnetic-trapped radiation, and exposure from possible onboard nuclear-propulsion engines. Risk models for astronaut exposure from such diverse components and modalities must be developed to assure adequate protection in future NASA missions. The low-level background exposures (GCR), including relativistic heavy ions (HZE), will be the ultimate limiting factor for astronaut career exposure. We consider herein a two-mutation, initiation-promotion, radiation-carcinogenesis model in mice in which the initiation stage is represented by a linear kinetics model of cellular repair/misrepair, including the track-structure model for heavy ion action cross-sections. The model is validated by comparison with the harderian gland tumor experiments of Alpen et al. for various ion beams. We apply the initiation-promotion model to exposures from galactic cosmic rays, using models of the cosmic-ray environment and heavy ion transport, and consider the effects of the age of the mice prior to and after the exposure and of the length of time in space on predictions of relative risk. Our results indicate that biophysical models of age-dependent radiation hazard will provide a better understanding of GCR risk than models that rely strictly on estimates of the initial slopes of these radiations. PMID:7480628

  15. On the 27-day Variations of Cosmic Ray Intensity in Recent Solar Minimum 23/24

    E-print Network

    Modzelewska, R

    2015-01-01

    We have studied the 27-day variations and their harmonics of the galactic cosmic ray (GCR) intensity, solar wind velocity, and interplanetary magnetic field (IMF) components in the recent prolonged solar minimum 23 24. The time evolution of the quasi-periodicity in these parameters connected with the Suns rotation reveals that their synodic period is stable and is aprox 26-27 days. This means that the changes in the solar wind speed and IMF are related to the Suns near equatorial regions in considering the differential rotation of the Sun. However, the solar wind parameters observed near the Earths orbit provide only the conditions in the limited local vicinity of the equatorial region in the heliosphere (within in latitude). We also demonstrate that the observed period of the GCR intensity connected with the Suns rotation increased up to aprox 33-36 days in 2009. This means that the process driving the 27-day variations of the GCR intensity takes place not only in the limited local surroundings of the equato...

  16. Serine-arginine-rich protein p30 directs alternative splicing of glucocorticoid receptor pre-mRNA to glucocorticoid receptor beta in neutrophils.

    PubMed

    Xu, Qing; Leung, Donald Y M; Kisich, Kevin O

    2003-07-18

    Glucocorticoid (GC) insensitivity is a major clinical challenge in the treatment of many inflammatory diseases. It has been shown previously that GC insensitivity, in several inflammatory cell types, is due to an overabundance of the beta isoform of the glucocorticoid receptor (GCRbeta) relative to the ligand binding isoform, GCRalpha. GCRbeta functions as a dominant inhibitor of GCRalpha action. A number of GCR isoforms are created from the same pre-mRNA transcript via alternative splicing, and the factor or factors that control alternative splicing of GCR pre-mRNA are of great importance. In the current study, we have identified the predominant alternative splicing factor present in human neutrophils, which is known to be exceptionally GC-insensitive. The predominant alternative splicing factor in neutrophils is SRp30c, which is one of several highly conserved serine-arginine-rich (SR) proteins that are involved in both constitutive and alternative splicing in eukaryotic cells. Inhibition of SRp30c expression with antisense oligonucleotide strongly inhibited expression of GCRbeta and stimulated expression of GCRalpha. Antisense molecules targeted to other SR proteins had no effect. Our data indicate that SRp30c is necessary for alternative splicing of the GCR pre-mRNA to create mRNA encoding GCRbeta. PMID:12738786

  17. Use of Apollo 17 Epoch Neutron Spectrum as a Benchmark in Testing LEND Collimated Sensor

    NASA Technical Reports Server (NTRS)

    Chin, Gordon; Sagdeev, R.; Milikh, G.

    2011-01-01

    The Apollo 17 neutron experiment LPNE provided a unique set of data on production of neutrons in the Lunar soil bombarded by Galactic Cosmic Rays (GCR). It serves as valuable "ground-truth" in the age of orbital remote sensing. We used the neutron data attributed to Apollo 17 epoch as a benchmark for testing the LEND's collimated sensor, as introduced by the geometry of collimator and efficiency of He3 counters. The latter is defined by the size of gas counter and pressure inside it. The intensity and energy spectrum of neutrons escaping the lunar surface are dependent on incident flux of Galactic Cosmic Rays (GCR) whose variability is associated with Solar Cycle and its peculiarities. We obtain first the share of neutrons entering through the field of view of collimator as a fraction of the total neutron flux by using the angular distribution of neutron exiting the Moon described by our Monte Carlo code. We computed next the count rate of the 3He sensor by using the neutron energy spectrum from McKinney et al. [JGR, 2006] and by consider geometry and gas pressure of the LEND sensor. Finally the neutron count rate obtained for the Apollo 17 epoch characterized by intermediate solar activity was adjusted to the LRO epoch characterized by low solar activity. It has been done by taking into account solar modulation potential, which affects the GCR flux, and in turn changes the neutron albedo flux.

  18. A temporal forecast of radiation environments for future space exploration missions.

    PubMed

    Kim, Myung-Hee Y; Cucinotta, Francis A; Wilson, John W

    2007-06-01

    The understanding of future space radiation environments is an important goal for space mission operations, design, and risk assessment. We have developed a solar cycle statistical model in which sunspot number is coupled to space-related quantities, such as the galactic cosmic radiation (GCR) deceleration potential (phi) and the mean occurrence frequency of solar particle events (SPEs). Future GCR fluxes were derived from a predictive model, in which the temporal dependence represented by phi was derived from GCR flux and ground-based Climax neutron monitor rate measurements over the last four decades. These results showed that the point dose equivalent inside a typical spacecraft in interplanetary space was influenced by solar modulation by up to a factor of three. It also has been shown that a strong relationship exists between large SPE occurrences and phi. For future space exploration missions, cumulative probabilities of SPEs at various integral fluence levels during short-period missions were defined using a database of proton fluences of past SPEs. Analytic energy spectra of SPEs at different ranks of the integral fluences for energies greater than 30 MeV were constructed over broad energy ranges extending out to GeV for the analysis of representative exposure levels at those fluences. Results will guide the design of protection systems for astronauts during future space exploration missions. PMID:17165049

  19. Nested Krylov methods and preserving the orthogonality

    NASA Technical Reports Server (NTRS)

    Desturler, Eric; Fokkema, Diederik R.

    1993-01-01

    Recently the GMRESR inner-outer iteraction scheme for the solution of linear systems of equations was proposed by Van der Vorst and Vuik. Similar methods have been proposed by Axelsson and Vassilevski and Saad (FGMRES). The outer iteration is GCR, which minimizes the residual over a given set of direction vectors. The inner iteration is GMRES, which at each step computes a new direction vector by approximately solving the residual equation. However, the optimality of the approximation over the space of outer search directions is ignored in the inner GMRES iteration. This leads to suboptimal corrections to the solution in the outer iteration, as components of the outer iteration directions may reenter in the inner iteration process. Therefore we propose to preserve the orthogonality relations of GCR in the inner GMRES iteration. This gives optimal corrections; however, it involves working with a singular, non-symmetric operator. We will discuss some important properties, and we will show by experiments that, in terms of matrix vector products, this modification (almost) always leads to better convergence. However, because we do more orthogonalizations, it does not always give an improved performance in CPU-time. Furthermore, we will discuss efficient implementations as well as the truncation possibilities of the outer GCR process. The experimental results indicate that for such methods it is advantageous to preserve the orthogonality in the inner iteration. Of course we can also use iteration schemes other than GMRES as the inner method; methods with short recurrences like GICGSTAB are of interest.

  20. [Results of statistical analysis of the dynamics of ionizing radiation dose fields in the service module of the International Space Station in 2000-2012].

    PubMed

    Mitrikas, V G

    2014-01-01

    The on-going 24th solar cycle (SC) is distinguished from the previous ones by low activity. On the contrary, levels of proton fluxes from galactic cosmic rays (GCR) are high, which increases the proton flow striking the Earth's radiation belts (ERB). Therefore, at present the absorbed dose from ERB protons should be calculated with consideration of the tangible increase of protons intensity built into the model descriptions based on experimental measurements during the minimum between cycles 19 and 20, and the cycle 21 maximum. The absorbed dose from GCR and ERB protons copies galactic protons dynamics, while the ERB electrons dose copies SC dynamics. The major factors that determine the absorbed dose value are SC phase, ISS orbital altitude and shielding of the dosimeter readings of which are used in analysis. The paper presents the results of dynamic analysis of absorbed doses measured by a variety of dosimeters, namely, R-16 (2 ionization chambers), DB8-1, DB8-2, DB8-3, DB8-4 as a function of ISS orbit altitude and SC phase. The existence of annual variation in the absorbed dose dynamics has been confirmed; several additional variations with the periods of 17 and 52 months have been detected. Modulation of absorbed dose variations by the SC and GCR amplitudes has been demonstrated. PMID:25035897

  1. Assessing access of galactic cosmic rays at Moon's orbit

    NASA Astrophysics Data System (ADS)

    Huang, Chia-Lin; Spence, Harlan E.; Kress, Brian T.

    2009-05-01

    Characterizing the lunar radiation environment is essential for preparing future robotic and human explorations on lunar bases. Galactic cosmic rays (GCR) represent one source of ionizing radiation at the Moon that poses a biological risk. Because GCR are charged particles, their paths are affected by the magnetic fields along their trajectories. Unlike the Earth, the Moon has no strong, shielding magnetic field of its own. However, as it orbits Earth, the Moon traverses not only the weak interplanetary magnetic field but also the distant magnetic tail of Earth's magnetosphere. We combine an empirical magnetic field model of Earth's magnetosphere with a fully-relativistic charged particle trajectory code to model and assess the access of GCR at the Moon's orbit. We follow protons with energies of 1, 10 and 100 MeV starting from an isotropic distribution at large distances outside a volume of space including Earth's magnetosphere and the lunar orbit. The simulation result shows that Earth's magnetosphere does not measurably modify protons of energy greater than 1 MeV at distances outside the geomagnetic cutoff imposed by Earth's strong dipole field very near to the planet. Therefore, in contrast to Winglee and Harnett (2007), we conclude that Earth's magnetosphere does not provide any substantial magnetic shielding at the Moon's orbit. These simulation results will be compared to LRO/CRaTER data after its planned launch in June 2009.

  2. 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 be

  3. Cosmogenic nuclides in the Martian surface: Constraints for sample recovery and transport

    NASA Technical Reports Server (NTRS)

    Englert, Peter A. J.

    1988-01-01

    Stable and radioactive cosmogenic nuclides and radiation damage effects such as cosmic ray tracks can provide information on the surface history of Mars. A recent overview on developments in cosmogenic nuclide research for historical studies of predominantly extraterrestrial materials was published previously. The information content of cosmogenic nuclides and radiation damage effects produced in the Martian surface is based on the different ways of interaction of the primary galactic and solar cosmic radiation (GCR, SCR) and the secondary particle cascade. Generally the kind and extent of interactions as seen in the products depend on the following factors: (1) composition, energy and intensity of the primary SCR and GCR; (2) composition, energy and intensity of the GCR-induced cascade of secondary particles; (3) the target geometry, i.e., the spatial parameters of Martian surface features with respect to the primary radiation source; (4) the target chemistry, i.e., the chemical composition of the Martian surface at the sampling location down to the minor element level or lower; and (5) duration of the exposure. These factors are not independent of each other and have a major influence on sample taking strategies and techniques.

  4. Solar-Cosmic-Ray-Produced Nuclides in Extraterrestrial Matter

    NASA Technical Reports Server (NTRS)

    Reedy, Robert C.

    1999-01-01

    There are two main types of cosmic rays that have sufficient energy to induce nuclear reactions -- the galactic cosmic rays (GCR) and solar cosmic rays (also called solar energetic particles). Both types of particles can have production rates and production ratios in the small objects often found in cold and hot deserts that are different from those seen for most meteorites, which typically have radii of approx. 10-100 centimeters. GCR production rates are often lower than those for most meteorites. GCR production ratios, such as Ne-22/Ne-21, are also often different in small objects. Smaller meteoroids also are more likely to have nuclides made by solar-cosmic-ray (SCR) particles than typically-sized meteorites. The very small meteorite Salem had large amounts of SCR-produced radionuclides. Meteorites recovered in Antarctica are more likely to contain SCR-produced nuclides than other meteorites. Martian and lunar meteorites are also likely to have SCR-produced nuclides. Production rates and profiles for SCR-produced nuclides in meteoroids have been calculated previously. However, the cross sections for the nuclear reactions making many SCR-produced nuclides, such as Be-10 were not well measured then. New rates and profiles are calculated here using good cross sections for the reactions making these nuclides.

  5. Solar-Cosmic-Ray-Produced Nuclides in Extraterrestrial Matter

    NASA Technical Reports Server (NTRS)

    Reedy, Robert C.

    2000-01-01

    There are two main types of cosmic rays that have sufficient energy to induce nuclear reactions -- the galactic cosmic rays (GCR) and solar cosmic rays (also called solar energetic particles). Both types of particles can have production rates and production ratios in the small objects often found in cold and hot deserts that are different from those seen for most meteorites, which typically have radii of approx.10-100 centimeters. GCR production rates are often lower than those for most meteorites. GCR production ratios, such as Ne-22/Ne-21, are also often different in small objects. Smaller meteoroids also are more likely to have nuclides made by solar-cosmic-ray (SCR) particles than typically-sized meteorites. The very small meteorite Salem had large amounts of SCR-produced radionuclides. Meteorites recovered in Antarctica are more likely to contain SCR-produced nuclides than other meteorites. Martian and lunar meteorites are also likely to have SCR-produced nuclides. Production rates and profiles for SCR-produced nuclides in meteoroids have been calculated previously. However, the cross sections for the nuclear reactions making many SCR-produced nuclides, such as Be-10, were not well measured then. New rates and profiles are calculated here using good cross sections for the reactions making these nuclides.

  6. Temporal variability of solar activity effects on the lower atmosphere and natural climatic oscillations

    NASA Astrophysics Data System (ADS)

    Veretenenko, Svetlana; Ogurtsov, Maxim

    Temporal variability of relationships between the Earth’s climate and solar activity is a very important problem in solar-terrestrial physics. In this work we continue studying possible reasons for this variability. The temporal evolution of correlations between troposphere pressure at extratropical latitudes and characteristics of solar activity (SA) and galactic cosmic rays (GCR) are compared with natural climatic oscillations. It was found that the ~60-year variations detected earlier in the amplitude and sign of SA/GCR effects (Veretenenko and Ogurtsov, 2012) correlate well with similar variations in global temperature anomalies, as well as meteorological characteristics of the polar atmosphere (the Arctic Oscillation). The results obtained suggest that the character of SA/GCR influence on the lower atmosphere depends on the epoch of the large-scale circulation which, in turn, seems to be closely related to the state of the polar vortex forming in the stratosphere of high latitudes. The evidences for a roughly 60-year periodicity in the vortex strength, as well as an important part of this periodicity in the mechanism of solar-climatic links are provided. This work was supported by the Presidium of the Russian Academy of Sciences (Project No. 22) and Russian Foundation for Basic Research (Grant No.13-02-00783). References: Veretenenko S., Ogurtsov M. (2012) Regional and temporal variability of solar activity and galactic cosmic ray effects on the lower atmosphere circulation. Adv. Space Res. 49, 770-783.

  7. Investigation of Galactic Cosmic Rays Modulation by the Corotating Interaction Regions

    NASA Astrophysics Data System (ADS)

    Guo, X.; Florinski, V. A.

    2014-12-01

    Corotating interaction regions (CIRs) are produced as a result of the interaction between fast and slowsolar-wind streams, and quite ubiquitous in every region of the heliosphere. Observations shown thatthe stream interfaces of CIRs between fast and slow solar wind streams and the leading edges of CIRsare responsible for the depressions of galactic cosmic rays (GCRs) intensity. Based on the well knownlocal-scale expansion of the ideal MHD conservation law and the developed global MHD model ofCIRs in the heliosphere, we perform the numerical investigation of the transport and turbulence of thesolar wind fluctuation in CIRs. Turbulent energy density and correlation length distribution throughoutthe heliosphere are presented, and further in turn used to compute the mean free path and perpendiculardiffusion coefficient of energetic particles. We attempt to use the plasma background from the globalMHD simulations and the transport coefficients in our existing stochastic cosmic-ray transport code tonumerically solve the Parker transport equation for GCRs. The modulated GCR spectrum from Voyager2 observations near the termination shock was used at the external boundary condition. The computedGCR spectral features and temporal profiles at any given location was directly compared withobservations by spacecraft based cosmic-ray detectors and neutron monitors on the ground, which willgreatly enhance our understanding of the physics of GCR modulation by the CIRs in heliosphere.

  8. Calibration of the Galactic Cosmic Ray Flux

    NASA Technical Reports Server (NTRS)

    Mathew, K. J.; Marti, K.

    2004-01-01

    We report first Xe data on the cross-calibration of I-129-Xe-129(sub n) ages with conventional CRE ages, a method which is expected to provide information on the long-term constancy of the galactic cosmic ray (GCR) flux. We studied isotopic signatures of Xe released in stepwise heating, decomposition and melting of troilites in the Cape York iron meteorite to identify isotopic shifts in Xe-129 and Xe-131 due to neutron capture in Te-128 and Te-130. We also resolve components due to extinct 129I, spallation and fission Xe. There has recently been much speculation on the constancy of GCR over long time scales, as may be inferred from iron meteorites. If GCRs originate from supernova events, this provides the basis for postulating increased fluxes at locations with higher than average densities of supernovae, specifically in OB-associations. The solar system at present appears to be inside a local bubble between spiral arms and may experience an increased GCR flux.

  9. Galactic cosmic ray exposure estimates for SAGE-3 mission in polar orbit

    NASA Technical Reports Server (NTRS)

    Nealy, John E.; Tipton, Bryan E.

    1992-01-01

    An analysis of the effects of galactic cosmic ray (GCR) exposures on charge-coupled devices (CCDs) was performed for the SAGE-III 5-year mission in sun-synchronous orbit between 1996 and 2001. A detailed environment model used in conjunction with a geomagnetic vertical cut-off code provides the predicted 5-year fluence of GCR ions. A computerized solid model of the spacecraft was used to define the effective shield thickness distribution around the CCD detector. The particle fluences at the detector location are calculated with the Langley heavy-ion transport code, and these fluences are used in conjunction with estimated nuclear stopping powers to evaluate dosimetric quantities related to the detector degradation. A previous study analyzing effects of trapped particle and solar flare protons indicated an approximate 20 percent reduction in detector sensitivity for the mission. The galactic cosmic ray contribution was thought to be relatively small and therefore was not previously analyzed. The present study provides quantification of the GCR effects, which are found to contribute less than 1 percent of the total environment degradation.

  10. Radiation considerations for interplanetary missions

    NASA Technical Reports Server (NTRS)

    Badwar, Gautam D.; Oneill, Patrick M.; Cucinotta, Francis A.

    1993-01-01

    Galactic cosmic radiation (GCR) poses a serious radiation hazard for long-duration missions. In designing a lunar habitat or Mars transfer vehicle, the worst-case radiation exposure determines shielding thickness and, hence, the weight of spacecraft. Using the spherically symmetric diffusion theory of the solar modulation of GCR, it was possible to use data on the differential energy spectra of hydrogen, helium, oxygen, and iron from 1954 to 1989 to show that the flux at 1 A.U. is determined by the diffusion parameter, K, which is a function of the time in the solar cycle. This analysis also showed that the solar minimum of 1976 to 1977 was the deepest minimum in the last 37 years. Using this theory, we have obtained the GCR spectra for all the nuclei and calculated the depth-dose as a function of aluminum shield thickness. Using the ICRP-26 definition of the quality factor, it is shown that the shielding required to stay below the LEO recommended annual limit of 50 cSv is 17.5 (+8, -3), g/sq cm of aluminum; if the limit is raised to 60 cSv, the required shielding is 9 (5, -1.5) g/sq cm. We also discuss the issues and shielding needs for protection against solar particle events.

  11. Full Mission Astronaut Radiation Exposure Assessments for Long Duration Lunar Surface Missions

    NASA Technical Reports Server (NTRS)

    Adamczyk, Anne; Clowdsley, Martha; Qualls, Garry; Blattnig, Steve; Lee, Kerry; Fry, Dan; Stoffle, Nicholas; Simonsen, Lisa; Slaba, Tony; Walker, Steven; Zapp, Edward

    2011-01-01

    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. For short missions, radiation risk is dominated by the possibility of a large Solar Particle Event (SPE). Longer duration missions have both SPE and Galactic Cosmic Ray (GCR) risks. SPE exposure can contribute significantly toward cancer induction in combination with GCR. As mission duration increases, mitigation strategies must address the combined risks from SPE and GCR exposure. In this paper, full mission exposure assessments were performed for the proposed long duration lunar surface mission scenarios. In order to accomplish these assessments, previously developed radiation shielding models for a proposed lunar habitat and rover were utilized. 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 the proposed timelines. Mission exposure results, assessed in terms of effective dose, are presented for the proposed timelines and recommendations are made for improved astronaut shielding and safer operational practices.

  12. The deep space galactic cosmic ray lineal energy spectrum at solar minimum

    NASA Astrophysics Data System (ADS)

    Case, A. W.; Kasper, J. C.; Spence, H. E.; Zeitlin, C. J.; Looper, M. D.; Golightly, M. J.; Schwadron, N. A.; Townsend, L. W.; Mazur, J. E.; Blake, J. B.; Iwata, Y.

    2013-06-01

    The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument is an energetic particle telescope on board the Lunar Reconnaissance Orbiter spacecraft. CRaTER measures energetic charged particles that have sufficient energy to penetrate the outer shielding of the instrument (about 12 MeV/nucleon). Galactic cosmic rays (GCR) with these energies are the primary radiation concern for spacecraft and astronauts outside of the Earth's magnetosphere during times of minimal solar activity. These particles can easily penetrate typical shielding and damage electronics, causing increased electronics failure rates and single event upsets. When this radiation impacts biological cells, it causes an increased risk of cancer. The CRaTER instrument was built to characterize the radiation dose and lineal energy with unprecedented time and energy resolution and was fortuitously flown during a period of time that coincided with the highest GCR fluxes in the modern space age. We report here this worst-case GCR lineal energy spectrum. Observations are made behind a thin aluminum window and different thicknesses of tissue-equivalent plastic. These measurements provide important observational data points to compare with current model predictions of the dose deposited by energetic particles within a tissue-like material.

  13. Radiation climate map for analyzing risks to astronauts on the mars surface from galactic cosmic rays

    NASA Astrophysics Data System (ADS)

    Saganti, Premkumar B.; Cucinotta, Francis A.; Wilson, John W.; Simonsen, Lisa C.; Zeitlin, Cary

    2004-01-01

    The potential risks for late effects including cancer, cataracts, and neurological disorders due to exposures to the galactic cosmic rays (GCR) is a large concern for the human exploration of Mars. Physical models are needed to project the radiation exposures to be received by astronauts in transit to Mars and on the Mars surface, including the understanding of the modification of the GCR by the Martian atmosphere and identifying shielding optimization approaches. The Mars Global Surveyor (MGS) mission has been collecting Martian surface topographical data with the Mars Orbiter Laser Altimeter (MOLA). Here we present calculations of radiation climate maps of the surface of Mars using the MOLA data, the radiation transport model HZETRN (high charge and high energy transport), and the quantum multiple scattering fragmentation model, QMSFRG. Organ doses and the average number of particle hits per cell nucleus from GCR components (protons, heavy ions, and neutrons) are evaluated as a function of the altitude on the Martian surface. Approaches to improve the accuracy of the radiation climate map, presented here using data from the 2001 Mars Odyssey mission, are discussed.

  14. Radiation Climate Map for Analyzing Risks to Astronauts on the Mars Surface from Galactic Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Saganti, Premkumar B.; Cucinotta, Francis A.; Wilson, John W.; Simonsen, Lisa C.; Zeitlin, Cary

    The potential risks for late effects including cancer, cataracts, and neurological disorders due to exposures to the galactic cosmic rays (GCR) is a large concern for the human exploration of Mars. Physical models are needed to project the radiation exposures to be received by astronauts in transit to Mars and on the Mars surface, including the understanding of the modification of the GCR by the Martian atmosphere and identifying shielding optimization approaches. The Mars Global Surveyor (MGS) mission has been collecting Martian surface topographical data with the Mars Orbiter Laser Altimeter (MOLA). Here we present calculations of radiation climate maps of the surface of Mars using the MOLA data, the radiation transport model HZETRN (high charge and high energy transport), and the quantum multiple scattering fragmentation model, QMSFRG. Organ doses and the average number of particle hits per cell nucleus from GCR components (protons, heavy ions, and neutrons) are evaluated as a function of the altitude on the Martian surface. Approaches to improve the accuracy of the radiation climate map, presented here using data from the 2001 Mars Odyssey mission, are discussed.

  15. Designing Spacecraft and Mission Operations Plans to Meet Flight Crew Radiation Dose Requirements: Why is this an "Epic Challenge" for Long-Term Manned Interplanetary Flight

    NASA Technical Reports Server (NTRS)

    Koontz, Steven

    2012-01-01

    Outline of presentation: (1) Radiation Shielding Concepts and Performance - Galactic Cosmic Rays (GCRs) (1a) Some general considerations (1b) Galactic Cosmic Rays (2)GCR Shielding I: What material should I use and how much do I need? (2a) GCR shielding materials design and verification (2b) Spacecraft materials point dose cosmic ray shielding performance - hydrogen content and atomic number (2c) Accelerator point dose materials testing (2d) Material ranking and selection guidelines (2e) Development directions and return on investment (point dose metric) (2f) Secondary particle showers in the human body (2f-1) limited return of investment for low-Z, high-hydrogen content materials (3) GCR shielding II: How much will it cost? (3a) Spacecraft design and verification for mission radiation dose to the crew (3b) Habitat volume, shielding areal density, total weight, and launch cost for two habitat volumes (3c) It's All about the Money - Historical NASA budgets and budget limits (4) So, what can I do about all this? (4a) Program Design Architecture Trade Space (4b) The Vehicle Design Trade Space (4c) Some Near Term Recommendations

  16. Commensal enteric bacteria engender a self-limiting humoral mucosal immune response while permanently colonizing the gut.

    PubMed Central

    Shroff, K E; Meslin, K; Cebra, J J

    1995-01-01

    We have employed a germfree mouse model to study the development and persistence of a humoral mucosal immune response to a gram-negative murine commensal organism, Morganella morganii. M. morganii bacteria rapidly colonize the gut, resulting in hypertrophy of Peyer's patches (PP), including germinal center reactions (GCR), and the development of specific immunoglobulin A (IgA) responses detected in vitro in PP fragment cultures and by ELISPOT assays of lamina propria cells. The GCR peaks 14 days after infection and begins to wane thereafter. Upon colonization, the organisms successfully translocate to the mesenteric lymph node and spleen, but the number of translocating bacteria begins to drop with the onset of a specific IgA response. A clonal B-cell microculture technique was used to determine the frequency of specific IgA plasmablasts and IgA memory cells. The frequencies of preplasmablasts were seen to be higher in the earlier stages of germinal center development, whereas the frequencies of antigen-specific memory cells appeared to remain at a relatively constant level even after 193 days postmonoassociation. We suggest that a successful secretory IgA response can attenuate chronic stimulation of GCR even though the bacteria persist in the gut. The observed developing hyporesponsiveness to a chronically present commensal organism may be relevant to the use of bacterial vectors for mucosal immunization. PMID:7558298

  17. Effects of Nuclear Cross Sections at Different Energies on Space Radiation Exposure from Galactic Cosmic Rays

    NASA Technical Reports Server (NTRS)

    Li, Zi-Wei; Adams, James H., Jr.

    2007-01-01

    Space radiation from galactic cosmic rays (GCR) is a major hazard to space crews, especially in long duration human space explorations. For this reason, they will be protected by radiation shielding that fragments the GCR heavy ions. Here we investigate how sensitive the crew's radiation exposure is to nuclear fragmentation cross sections at different energies. We find that in deep space cross sections between about 0.2 and 1.2 GeV/u have the strongest effect on dose equivalent behind shielding in solar minimum GCR environments, and cross sections between about 0.6 and 1.7 GeV/u are the most important at solar maximum'. On the other hand, at the location of the International Space Station, cross sections at_higher -energies, between about 0.6 and 1.7 GeV /u at solar minimum and between about 1.7 and 3.4 GeV/u'at,solar maximum, are the most important This is. due-to the average geomagnetic cutoff for the ISS orbit. We also show the effect of uncertainties in the fragmentation cross sections on the elemental energy spectra behind shielding. These results help to focus the studies of fragmentation cross sections on the proper energy range in order to improve our predictions of crew exposures.

  18. Schema-based Scheduling of Event Processors and Buffer Minimization for Queries on Structured Data Streams

    Microsoft Academic Search

    Christoph Koch; Stefanie Scherzinger; Nicole Schweikardt; Bernhard Stegmaier

    2004-01-01

    We introduce an extension of the XQuery lan- guage, FluX, that supports event-based query processing and the conscious handling of main memory buffers. Purely event-based queries of this language can be executed on stream- ing XML data in a very direct way. We then develop an algorithm that allows to efficiently rewrite XQueries into the event-based FluX language. This algorithm

  19. Galactic Cosmic Rays in the inner magnetosphere of Saturn

    NASA Astrophysics Data System (ADS)

    Kotova, Anna; Roussos, Elias; Krupp, Norbert; Dandouras, Iannis

    2015-04-01

    Existence of the Saturn innermost radiation belt in the tiny gap between planetary atmosphere and D-ring was first proposed in 2004 after the discovery of the significant fluxes of the energetic neutral atoms (ENA) coming from this area, what was measured by Ion and Neutron Camera on board of Cassini during the insertion orbit (1). One of the main sources of energetic charged particles for such inner radiation belt is the interaction of the Galactic Cosmic Rays (GCR) with the Saturn's atmosphere and rings, which due to CRAND process can produce the keV-MeV ions or electrons in the region. Using charged particles tracer developed in our group, we simulate the motion of the GCR using the backward tracing method and analyze the differences, arising from the usage of different magnetospheric models. The simulation was performed under assumptions of the dipole magnetic field model, then using more complex model with a magnetic equator offset and some other non-dipolar effects and later on using the Khurana model (2), which is based on the Cassini observations and for today is the most realistic model of the Saturn magnetosphere. We created maps of the GCR access to the Saturn atmosphere, analyzed changes of the minimum energy needed for GCR to reach the planet from different directions depending on the latitude and longitude and explained difference with analytically derived by Stormer theory values. Using those simulations and combine its results with Saturn atmospheric model and rings composition model, we estimate the production of secondaries resulting from the interaction of the GCR with atmosphere and from its penetration of the rings. This allows us to estimate the flux of energetic particles close to the planet, what will be useful for the preparation of the final "proximal" orbits of the Cassini spacecraft in 2017. For the validation of the results they are compared with the data from the Cassini insertion orbit. References: (1) S. M. Krimigis et al., "Dynamics of Saturn's Magnetosphere from MIMI During Cassini's Orbital Insertion", Science 25 February 2005: 307 (5713), 1270-1273. (2) Khurana, K. K., C. S. Arridge, H. Schwarzl, and M. K. Dougherty (2006b), A model of Saturn's magnetospheric field based on latest Cassini observations, Eos Trans. AGU, 87(36), Jt. Assem. Suppl., Abstract P44A-01.

  20. An analytical model for the prediction of a micro-dosimeter response function

    NASA Astrophysics Data System (ADS)

    Badavi, F. F.; Xapsos, M. A.; Wilson, J. W.

    2009-07-01

    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 (GCRs) 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 s/ion. The ionizing radiation environment at LEO is represented by O'Neill's GCR model (2004), covering charged particles in the 1 ? Z ? 28 range. 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.

  1. Bacteraemia caused by third-generation cephalosporin-resistant Escherichia coli in France: prevalence, molecular epidemiology and clinical features.

    PubMed

    Courpon-Claudinon, A; Lefort, A; Panhard, X; Clermont, O; Dornic, Q; Fantin, B; Mentré, F; Wolff, M; Denamur, E; Branger, C

    2011-04-01

    Escherichia coli is one of the major pathogens responsible for bactaeremia. Empirical antibiotherapy of these infections usually relies on third-generation cephalosporins (3GCs). Thus, the occurrence and epidemiology of 3GC-resistant strains have to be monitored. The French prospective multicentre study COLIBAFI collected 1081 strains of E. coli responsible for bacteraemia in 2005. In the present work, the prevalence of resistance to 3GCs was evaluated, and the implicated molecular mechanisms were characterized by specific PCR and sequencing. Phylogenetic grouping, O-typing, pulsed-field gel electrophoresis and virulence factor analysis were used to investigate the genetic background of the 3GC-resistant (3GC-R) strains. Clinical features of the patients with documented data (n = 1051) were analysed. Decreased susceptibility to 3GCs was observed in 41 strains (3.8%): 19, 18 and four had extended-spectrum ?-lactamase (ESBL), AmpC cephalosporinase and OXA-type penicillinase phenotypes, respectively. Pulsed-field gel electrophoresis revealed that the 3GC-R strains constitute a diverse population. All but one of the strains with an ESBL phenotype produced a CTX-M-type enzyme, and six of them belonged to the widespread intercontinental clone O25b:H4-ST131. AmpC phenotype strains harboured various chromosomal ampC promoter and coding region mutations and/or the bla(CMY-2) plasmidic gene. 3GC-R strains carried fewer virulence factors and were more co-resistant to other antibiotics than 3GC-susceptible (3GC-S) strains. Infections with 3GC-R strains were mostly community-acquired and, as compared with those caused by their 3GC-S counterparts, were more severe. Underlying chronic disease and prior use of antibiotics were independent risk factors for development of a 3GC-R strain bacteraemia. The fact that the molecular support of 3GC resistance is mainly plasmid-mediated represents a potentially epidemic threat. PMID:20649802

  2. F. Saglietti and N. Oster (Eds.): SAFECOMP 2007, LNCS 4680, pp. 276282, 2007. Springer-Verlag Berlin Heidelberg 2007

    E-print Network

    Belli, Fevzi

    applications requir- ing extensive testing lasting several months, both testability and the choice of tests safety requirements. State-based and event-based methods have been used for almost four decades-Verlag Berlin Heidelberg 2007 Modeling, Analysis and Testing of Safety Issues - An Event-Based Approach and Case

  3. Coupled W-Os-Pt isotope systematics in IVB iron meteorites: In situ neutron dosimetry for W isotope chronology

    NASA Astrophysics Data System (ADS)

    Wittig, N.; Humayun, M.; Brandon, A. D.; Huang, S.; Leya, I.

    2013-01-01

    Tungsten isotope compositions of magmatic iron meteorites yield ages of differentiation that are within ±2 Ma of the formation of CAIs, with the exception of IVB irons that plot to systematically less radiogenic compositions yielding erroneously old ages. Secondary neutron capture due to galactic cosmic ray (GCR) irradiation is known to lower the ?182W of iron meteorites, adequate correction of which requires a measure of neutron dosage which has not been available, thus far. The W, Os and Pt isotope systematics of 12 of the 13 known IVB iron meteorites were determined by MC-ICP-MS (W, Os, Pt) and TIMS (Os). On the same dissolutions that yield precise ?182W, stable Os and Pt isotopes were determined as in situ neutron dosimeters for empirical correction of the ubiquitous cosmic-ray induced burn-out of 182W in iron meteorites. The W isotope data reveal a main cluster with ?182W of ˜-3.6, but a much larger range than observed in previous studies including irons (Weaver Mountains and Warburton Range) that show essentially no cosmogenic effect on their ?182W. The IVB data exhibits resolvable negative anomalies in ?189Os (-0.6?) and complementary ?190Os anomalies (+0.4?) in Tlacotepec due to neutron capture on 189Os which has approximately the same neutron capture cross section as 182W, and captures neutrons to produce 190Os. The least irradiated IVB iron, Warburton Range, has ?189Os and ?190Os identical to terrestrial values. Similarly, Pt isotopes, which are presented as ?192Pt, ?194Pt and ?196Pt range from +4.4? to +53?, +1.54? to -0.32? and +0.73? to -0.20?, respectively, also identify Tlacotepec and Dumont as the most GCR-damaged samples. In W-Os and W-Pt isotope space, the correlated isotope data back-project toward a 0-epsilon value of ?192Pt, ?189Os and ?190Os from which a pre-GCR irradiation ?182W of -3.42±0.09 (2?) is derived. This pre-GCR irradiation ?182W is within uncertainty of the currently accepted CAI initial ?182W. The Pt and Os isotope correlations in the IVB irons are in good agreement with a nuclear model for spherical irons undergoing GCR spallation, although this model over-predicts the change of ?182W by ˜2×, indicating a need for better W neutron capture cross section determinations. A nucleosynthetic effect in ?184W in these irons of -0.14±0.08 is confirmed, consistent with the presence of Mo and Ru isotope anomalies in IVB irons. The lack of a non-GCR Os isotope anomaly in these irons requires more complex explanations for the production of W, Ru and Mo anomalies than nebular heterogeneity in the distribution of s-process to r-process nuclides.

  4. Radiation Protection Effectiveness of Polymeric Based Shielding Materials at Low Earth Orbit

    NASA Technical Reports Server (NTRS)

    Badavi, Francis F.; Stewart-Sloan, Charlotte R.; Wilson, John W.; Adams, Daniel O.

    2008-01-01

    Correlations of limited ionizing radiation measurements onboard the Space Transportation System (STS; shuttle) and the International Space Station (ISS) with numerical simulations of charged particle transport through spacecraft structure have indicated that usage of hydrogen rich polymeric materials improves the radiation shielding performance of space structures as compared to the traditionally used aluminum alloys. We discuss herein the radiation shielding correlations between measurements on board STS-81 (Atlantis, 1997) using four polyethylene (PE) spheres of varying radii, and STS-89 (Endeavour, 1998) using aluminum alloy spheres; with numerical simulations of charged particle transport using the Langley Research Center (LaRC)-developed High charge (Z) and Energy TRaNsport (HZETRN) algorithm. In the simulations, the Galactic Cosmic Ray (GCR) component of the ionizing radiation environment at Low Earth Orbit (LEO) covering ions in the 1< or equals Z< or equals 28 range is represented by O'Neill's (2004) model. To compute the transmission coefficient for GCR ions at LEO, O'Neill's model is coupled with the angular dependent LaRC cutoff model. The trapped protons/electrons component of LEO 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 resulting from interaction of GCR ions with upper atmosphere is modeled through extrapolation of the Atmospheric Ionizing Radiation (AIR) measurements. With the validity of numerical simulations through correlation with PE and aluminum spheres measurements established, we further present results from the expansion of the simulations through the selection of high hydrogen content commercially available polymeric constituents such as PE foam core and Spectra fiber(Registered TradeMark) composite face sheet to assess their radiation shield properties as compared to generic PE.

  5. EXPOSE-R cosmic radiation time profile

    NASA Astrophysics Data System (ADS)

    Dachev, Tsvetan; Horneck, Gerda; Häder, Donat-Peter; Schuster, Martin

    2015-01-01

    The aim of the paper is to present the time profile of cosmic radiation exposure obtained by the radiation risks radiometer-dosimeter (R3DR) during the ESA exposition facility for EXPOSE-R mission (EXPOSE-R) in the EXPOSE-R facility outside the Russian Zvezda module of the International Space Station (ISS). Another aim is to make the obtained results available to other EXPOSE-R teams for use in their data analysis. R3DR is a low mass and small dimensions automated device, which measures solar radiation in four channels and in addition cosmic ionizing radiation. The main results of cosmic ionizing radiation measurements are: three different radiation sources were detected and quantified: galactic cosmic rays (GCR), energetic protons from the inner radiation belt (IRB) in the region of the South Atlantic anomaly and energetic electrons from the outer radiation belt (ORB). The highest daily averaged absorbed dose rate of 506 ?Gy day-1 came from IRB protons; GCR delivered much smaller daily absorbed dose rates of 81.4 ?Gy day-1 on average, and ORB source delivered on average a dose rate of 89 ?Gy day-1. The IRB and ORB daily averaged absorbed dose rates were higher than those observed during the ESA exposition facility for EXPOSE-E mission (EXPOSE-E), whereas the GCR rate was smaller than that measured during the EXPOSE-E mission. The reason for this difference is much less surrounding constructions shielding of the R3DR instrument in comparison with the R3DE instrument.

  6. A stochastic simulation of the propagation of Galactic cosmic rays reflecting the discreteness of cosmic ray sources Age and path length distribution

    NASA Astrophysics Data System (ADS)

    Miyake, S.; Muraishi, H.; Yanagita, S.

    2015-01-01

    Aims: The path length distribution of Galactic cosmic rays (GCRs) is the fundamental ingredient for modeling the propagation process of GCRs based on the so-called weighted slab method. We try to derive this distribution numerically by taking into account the discreteness in both space and time of occurrences of supernova explosions where GCRs are suspected to be born. The resultant age distribution and ratio of B/C are to be compared with recent observations. Methods: We solve numerically the stochastic differential equations equivalent to the Parker diffusion-convection equation which describes the propagation process of GCR in the Galaxy. We assume the three-dimensional diffusion is an isotropic one without any free escape boundaries. We ignore any energy change of GCRs and the existence of the Galactic wind for simplicity. We also assume axisymmetric configurations for the density distributions of the interstellar matter and for the surface density of supernovae. We have calculated age and path length of GCR protons arriving at the solar system with this stochastic method. The obtained age is not the escape time of GCRs from the Galaxy as usually assumed, but the time spent by GCRs during their journey to the solar system from the supernova remnants where they were born. Results: The derived age and path length show a distribution spread in a wide range even for GCR protons arriving at the solar system with the same energy. The distributions show a cut-off at a lower range in age or path length depending on the energy of GCRs. These cut-offs clearly come from the discreteness of occurrence of supernovae. The mean age of GeV particles obtained from the distributions is consistent with the age obtained by direct observation of radioactive secondary nuclei. The energy dependence of the B/C ratio estimated with the path length distribution reproduces reliably the energy dependence of B/C obtained by recent observations in space.

  7. Space Weather Nowcasting of Atmospheric Ionizing Radiation for Aviation Safety

    NASA Technical Reports Server (NTRS)

    Mertens, Christopher J.; Wilson, John W.; Blattnig, Steve R.; Solomon, Stan C.; Wiltberger, J.; Kunches, Joseph; Kress, Brian T.; Murray, John J.

    2007-01-01

    There is a growing concern for the health and safety of commercial aircrew and passengers due to their exposure to ionizing radiation with high linear energy transfer (LET), particularly at high latitudes. The International Commission of Radiobiological Protection (ICRP), the EPA, and the FAA consider the crews of commercial aircraft as radiation workers. During solar energetic particle (SEP) events, radiation exposure can exceed annual limits, and the number of serious health effects is expected to be quite high if precautions are not taken. There is a need for a capability to monitor the real-time, global background radiations levels, from galactic cosmic rays (GCR), at commercial airline altitudes and to provide analytical input for airline operations decisions for altering flight paths and altitudes for the mitigation and reduction of radiation exposure levels during a SEP event. The Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) model is new initiative to provide a global, real-time radiation dosimetry package for archiving and assessing the biologically harmful radiation exposure levels at commercial airline altitudes. The NAIRAS model brings to bear the best available suite of Sun-Earth observations and models for simulating the atmospheric ionizing radiation environment. Observations are utilized from ground (neutron monitors), from the atmosphere (the METO analysis), and from space (NASA/ACE and NOAA/GOES). Atmospheric observations provide the overhead shielding information and the ground- and space-based observations provide boundary conditions on the GCR and SEP energy flux distributions for transport and dosimetry simulations. Dose rates are calculated using the parametric AIR (Atmospheric Ionizing Radiation) model and the physics-based HZETRN (High Charge and Energy Transport) code. Empirical models of the near-Earth radiation environment (GCR/SEP energy flux distributions and geomagnetic cut-off rigidity) are benchmarked against the physics-based CMIT (Coupled Magnetosphere- Ionosphere-Thermosphere) and SEP-trajectory models.

  8. Modeling the Relationship Between Neutron Counting Rates and Sunspot Numbers Using the Hysteresis Effect

    NASA Astrophysics Data System (ADS)

    Inceoglu, F.; Knudsen, M. F.; Karoff, C.; Olsen, J.

    2014-04-01

    Several studies show that temporal variations in the Galactic cosmic ray (GCR) intensity display a distinct 11-year periodicity due to solar modulation of the galactic cosmic rays in the heliosphere. The 11-year periodicity of GCRs is inversely proportional to, but out of phase with, the 11-year solar cycle, implying that there is a time lag between actual solar cycle and the GCR intensity, which is known as the hysteresis effect. In this study, we use the hysteresis effect to model the relationship between neutron counting rates (NCRs), an indicator of the GCR intensity, and sunspot numbers (SSNs) over the period that covers the last four solar cycles (20, 21, 22, and 23). Both linear and ellipse models were applied to SSNs during odd and even cycles in order to calculate temporal variations of NCRs. We find that ellipse modeling provides higher correlation coefficients for odd cycles compared to linear models, e.g. 0.97, 0.97, 0.92, and 0.97 compared to 0.69, 0.72, 0.53, and 0.68 for data from McMurdo, Swarthmore, South Pole, and Thule neutron monitors, respectively, during solar cycle 21 with overall improvement of 31 % for odd cycles. When combined to a continuous model, the better correlation observed for the odd cycles increases the overall correlation between observed and modeled NCRs. The new empirical model therefore provides a better representation of the relationship between NCRs and SSNs. A major goal of the ongoing research is to use the new non-linear empirical model to reconstruct SSNs on annual time scales prior to 1610, where we do not have observational records of SSNs, based on changes in NCRs reconstructed from 10Be in ice cores.

  9. Pion and electromagnetic contribution to dose: Comparisons of HZETRN to Monte Carlo results and ISS data

    NASA Astrophysics Data System (ADS)

    Slaba, Tony C.; Blattnig, Steve R.; Reddell, Brandon; Bahadori, Amir; Norman, Ryan B.; Badavi, Francis F.

    2013-07-01

    Recent work has indicated that pion production and the associated electromagnetic (EM) cascade may be an important contribution to the total astronaut exposure in space. Recent extensions to the deterministic space radiation transport code, HZETRN, allow the production and transport of pions, muons, electrons, positrons, and photons. In this paper, the extended code is compared to the Monte Carlo codes, Geant4, PHITS, and FLUKA, in slab geometries exposed to galactic cosmic ray (GCR) boundary conditions. While improvements in the HZETRN transport formalism for the new particles are needed, it is shown that reasonable agreement on dose is found at larger shielding thicknesses commonly found on the International Space Station (ISS). Finally, the extended code is compared to ISS data on a minute-by-minute basis over a seven day period in 2001. The impact of pion/EM production on exposure estimates and validation results is clearly shown. The Badhwar-O'Neill (BO) 2004 and 2010 models are used to generate the GCR boundary condition at each time-step allowing the impact of environmental model improvements on validation results to be quantified as well. It is found that the updated BO2010 model noticeably reduces overall exposure estimates from the BO2004 model, and the additional production mechanisms in HZETRN provide some compensation. It is shown that the overestimates provided by the BO2004 GCR model in previous validation studies led to deflated uncertainty estimates for environmental, physics, and transport models, and allowed an important physical interaction (?/EM) to be overlooked in model development. Despite the additional ?/EM production mechanisms in HZETRN, a systematic under-prediction of total dose is observed in comparison to Monte Carlo results and measured data.

  10. Evaluations of Risks from the Lunar and Mars Radiation Environments

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee; Hayat, Matthew J.; Feiveson, Alan H.; Cucinotta, Francis A.

    2008-01-01

    Protecting astronauts from the space radiation environments requires accurate projections of radiation in future space missions. 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. The galactic cosmic radiation (GCR) flux for the next solar cycle was estimated as a function of interplanetary deceleration potential, which has been derived from GCR flux and Climax neutron monitor rate measurements over the last 4 decades. For the chaotic nature of solar particle event (SPE) occurrence, the mean frequency of SPE at any given proton fluence threshold during a defined mission duration was obtained from a Poisson process model using proton fluence measurements of SPEs during the past 5 solar cycles (19-23). Analytic energy spectra of 34 historically large SPEs were constructed over broad energy ranges extending to GeV. Using an integrated space radiation model (which includes the transport codes HZETRN [1] and BRYNTRN [2], and the quantum nuclear interaction model QMSFRG[3]), the propagation and interaction properties of the energetic nucleons through various media were predicted. Risk assessment from GCR and SPE was evaluated at the specific organs inside a typical spacecraft using CAM [4] model. The representative risk level at each event size and their standard deviation were obtained from the analysis of 34 SPEs. Risks from different event sizes and their frequency of occurrences in a specified mission period were evaluated for the concern of acute health effects especially during extra-vehicular activities (EVA). The results will be useful for the development of an integrated strategy of optimizing radiation protection on the lunar and Mars missions. Keywords: Space Radiation Environments; Galactic Cosmic Radiation; Solar Particle Event; Radiation Risk; Risk Analysis; Radiation Protection.

  11. High Energy Utilization, Co-Generation Nuclear power Plants With Static Energy Conversion

    SciTech Connect

    El-Genk, Mohamed S.; Tournier, Jean-Michel P. [Institute for Space and Nuclear Power Studies and Chemical and Nuclear Engineering Department, The University of New Mexico, Albuquerque, NM (United States)

    2002-07-01

    In addition to being cost effective, very small nuclear power plants with static energy conversion could meet the needs and the energy mix in underdeveloped countries and remote communities, which may include electricity, residential and industrial space heating, seawater desalination, and/or high temperature process heat or steam for industrial uses. These plants are also an attractive option in naval, marine, and undersea applications, when the absence of a sound signature is highly desirable. An Analysis is performed of Gas Cooled Reactor (CGR) and Liquid Metal Cooled Reactor (LMR), very small nuclear power plants with static energy conversion, using a combination of options. These include Alkali Metal Thermal-to-Electric Converters (AMTECs) and both single segment and segmented thermoelectric converters. The total energy utilization of these plants exceeds 88%. It includes the fraction of the reactor's thermal power converted into electricity and delivered to the Grid at 6.6 kVA and those used for residential and industrial space heating at {approx}370 K, seawater desalination at 400 K, and/or high temperature process heat or steam at {approx}850 K. In addition to its inherently high reliability, modularity, low maintenance and redundancy, static energy conversion used in the present study could deliver electricity to the Grid at a net efficiency of 29.5%. A LMR plant delivers 2-3 times the fraction of the reactor thermal power converted into electricity in a GCR plant, but could not provide for both seawater desalination and high temperature process heat/steam concurrently, which is possible in GCR plants. The fraction of the reactor's thermal power used for non-electrical power generation in a GCR plant is {approx} 10 - 15% higher than in a LMR plant. (authors)

  12. Development and application of one-step multiplex reverse transcription PCR for simultaneous detection of five diarrheal viruses in adult cattle.

    PubMed

    Fukuda, Masaharu; Kuga, Kazufumi; Miyazaki, Ayako; Suzuki, Tohru; Tasei, Keito; Aita, Tsunehiko; Mase, Masaji; Sugiyama, Makoto; Tsunemitsu, Hiroshi

    2012-06-01

    A one-step multiplex reverse transcription (RT)-PCR method was developed for the simultaneous detection of five viruses causing diarrhea in adult cattle: bovine group A rotavirus (GAR), bovine group B rotavirus (GBR), bovine group C rotavirus (GCR), bovine coronavirus (BCV), and bovine torovirus (BToV). The detection limit of the one-step multiplex RT-PCR for GAR, GCR, BCV, and BToV was 10(2), 10(0), 10(1), and 10(2) TCID(50)/ml, respectively, and that for GBR was 10(6) copies/ml. The one-step multiplex RT-PCR with newly designed primers to detect GAR had higher sensitivity than a single RT-PCR with conventional primers, with no false-positive reactions observed for ten other kinds of bovine RNA viruses To assess its field applicability, 59 of 60 fecal samples containing one of these five viruses from all 25 epidemic diarrhea outbreaks in adult cattle were positive in the one-step multiplex RT-PCR assay. Furthermore, using four additional fecal samples containing two viruses (GBR and BCV or BToV), two amplified products of the expected sizes were obtained simultaneously. In contrast, all 80 fecal samples lacking the five target viruses from normal adult cattle were negative in the multiplex assay. Taken together, our results indicate that the one-step multiplex RT-PCR developed here for the detection of GAR, GBR, GCR, BCV, and BToV can be expected to be a useful tool for the rapid and cost-effective diagnosis and surveillance of viral diarrhea in adult cattle. PMID:22407445

  13. Protection from Space Radiation

    NASA Technical Reports Server (NTRS)

    Tripathi, R. K.; Wilson, J. W.; Shinn, J. L.; Singleterry, R. C.; Clowdsley, M. S.; Cucinotta, F. A.; Badhwar, G. D.; Kim, M. Y.; Badavi, F. F.; Heinbockel, J. H.

    2000-01-01

    The exposures anticipated for our astronauts in the anticipated Human Exploration and Development of Space (HEDS) will be significantly higher (both annual and carrier) than any other occupational group. In addition, the exposures in deep space result largely from the Galactic Cosmic Rays (GCR) for which there is as yet little experience. Some evidence exists indicating that conventional linear energy transfer (LET) defined protection quantities (quality factors) may not be appropriate [1,2]. The purpose of this presentation is to evaluate our current understanding of radiation protection with laboratory and flight experimental data and to discuss recent improvements in interaction models and transport methods.

  14. Cosmic ray produced nitrogen in extra terrestrial matter

    Microsoft Academic Search

    K. J. Mathew; S. V. S. Murty

    1993-01-01

    Production rates of15N by both solar cosmic rays (SCR) and galactic cosmic rays (GCR) have been calculated for moon, as well as meteorites of various\\u000a sizes. Our production rates of15N which considered both the reaction channels16O(p, pn)15O and16O(p, 2p)15N separately are about 30% higher than those by Reedy (1981) who considered only the channel16O(p, pn)15O and used an empirical scaling

  15. Miniaturized Gas Correlation Radiometer for the Detection of Trace Gases in the Martian Atmosphere

    NASA Astrophysics Data System (ADS)

    Melroy, H.; Wilson, E. L.; Georgieva, E.

    2012-12-01

    We present a miniaturized and simplified version of a gas correlation radiometer (GCR) capable of simultaneously mapping multiple trace gases and identifying active regions on the Mars surface. Gas correlation radiometry (GCR) has been shown to be a sensitive and versatile method for detecting trace gases in Earth's atmosphere. Reduction of the size and mass of the GCR was achieved by implementing compact, light-weight 1 mm inner diameter hollow-core optical fibers (hollow waveguides) as the gas correlation cells. In a comparison with an Earth orbiting CO2 GCR instrument, exchanging the 10 m multipass cells with hollow waveguide gas correlation cells of equivalent pathlength reduces the mass from ~150 kg to ~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 1 meter in diameter by 0.05 m in height (mass and volume reductions of >99%). A unique feature of this instrument is its stackable module design, with a single module for each trace gas. Each of the modules is self-contained, and fundamentally identical; differing by the bandpass filter wavelength range and gas mixtures inside the hollow-waveguide absorption cells. The current configuration contains four stacked modules for simultaneous measurements of methane (CH4), formaldehyde (H2CO), water vapor (H2O), and deuterated water vapor (HDO) but could easily 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. Preliminary results indicate that a 1 ppb detection limit is possible for both formaldehyde and methane with one second of averaging. Using non-optimized components, we have demonstrated an instrument sensitivity equivalent to ~30 ppb for formaldehyde, and ~500 ppb for methane. We expect custom bandpass filters and 6 m long waveguides to significantly improve these promising results. Ongoing testing is being conducted on water vapor and deuterated water vapor.

  16. Miniaturized Gas Correlation Radiometer for the Detection of Trace Gases in the Martian Atmosphere

    NASA Technical Reports Server (NTRS)

    Melroy, Hilary R.; Wilson, Emily L.; Georgieva, Elena

    2012-01-01

    We present a miniaturized and simplified version of a gas correlation radiometer (GCR) capable of simultaneously mapping multiple trace gases and identifying active regions on the Mars surface. Gas correlation radiometry (GCR) has been shown to be a sensitive and versatile method for detecting trace gases in Earth's atmosphere. Reduction of the size and mass of the GCR was achieved by implementing compact, light-weight 1 mm inner diameter hollow-core optical fibers (hollow waveguides) as the gas correlation cells. In a comparison with an Earth orbiting CO2 GCR instrument, exchanging the 10 m multipass cells with hollow waveguide gas correlation cells of equivalent path length reduces the mass from approximately 150 kg to approximately 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 1 meter in diameter by 0.05 m in height (mass and volume reductions of greater than 99%). A unique feature of this instrument is its stackable module design, with a single module for each trace gas. Each of the modules is self-contained, and fundamentally identical; differing by the bandpass filter wavelength range and gas mixtures inside the hollow-waveguide absorption cells. The current configuration contains four stacked modules for simultaneous measurements of methane (CH4), formaldehyde (H2CO), water vapor (H2O), and deuterated water vapor (HDO) but could easily 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. Preliminary results indicate that a 1 ppb detection limit is possible for both formaldehyde and methane with one second of averaging. Using non-optimized components, we have demonstrated an instrument sensitivity equivalent to approximately 30 ppb for formaldehyde, and approximately 500 ppb for methane. We expect custom bandpass filters and 6 m long waveguides to significantly improve these promising results. Ongoing testing is being conducted on water vapor and deuterated water vapor.

  17. Biological effectiveness of nuclear fragments produced by high-energy protons interacting in tissues near the bone- soft tissue interface

    NASA Astrophysics Data System (ADS)

    Shavers, Mark Randall

    1999-12-01

    High-energy protons in the galactic cosmic rays (GCR)-or generated by nuclear interactions of GCR heavy-ions with material-are capable of penetrating great thicknesses of shielding to irradiate humans in spacecraft or in lunar or Martian habitats. As protons interact with the nuclei of the elemental constituents of soft tissue and bone, low energy nuclei-target fragments-are emitted into the cells responsible for bone development and maintenance and for hematopoiesis. Leukemogenesis is the principal endpoint of concern because it is the most likely deleterious effect, and it has a short latency period and comparatively low survival rate, although other myelo- proliferative disorders and osteosarcoma also may be induced. A one-dimensional proton-target fragment transport model was used to calculate the energy spectra of fragments produced in bone and soft tissue, and present in marrow cavities at distances from a bone interface. In terms of dose equivalent, the target fragments are as significant as the incident protons. An average radiation quality factor was found to be between 1.8 and 2.6. Biological response to the highly non- uniform energy deposition of the target fragments is such that an alternative approach to conventional predictive risk assessment is needed. Alternative procedures are presented. In vitro cell response and relative biological effectiveness were calculated from the radial dose distribution of each fragment produced by 1-GeV protons using parameters of a modified Ion-Gamma- Kill (IGK) model of radiation action. The modelled endpoints were survival of C3H10t 1/2 and V79 cells, neoplastic transformation of C3H10t1/2 cells, and mutation of the X-linked hypoxanthine phosphoribosyltransferase (HPRT) locus in V79 cells. The dose equivalent and cell responses increased by 10% or less near the interface. Since RBE increases with decreasing dose in the IGK model, comparisons with quality factors were made at dose levels 0.01 <= D [Gy] <= 2. Applying average quality factors derived herein to GCR exposures results in a <= 5% increase of in average quality. Calculated RBEs indicate that accepted quality factors for high-energy protons may be too low due to the relatively high effectiveness of the low-charged target fragments. Derived RBEs for target fragments increase the calculated biological effectiveness of GCR by 20% to 180%.

  18. Grey Component Replacement In Newspaper Printing

    NASA Astrophysics Data System (ADS)

    Juhola, Helene

    1990-06-01

    The possibilities to achieve a good four-colour print quality are much more limited in newspaper printing than in heat-set or gravure web printing. Nevertheless, the percentage of four-colour printing and, consequently, the quality requirements continue to grow in newspapers. One way of making the printer's work easier in the colour separation process is the socalled Grey Component Replacement (GCR). This technology has been available with digital scanners for several years. Our laboratory has also studied its applicability, especially in newspaper printing, on different occasions.

  19. Space Radiation Superconducting Shields

    NASA Astrophysics Data System (ADS)

    R-Musenich; Calvelli, V.; Farinon, S.; Burger, W. J.; Battiston, R.

    2014-05-01

    The interest on shields to protect astronauts I long term missions against GCR has recently grown and several projects have been funded. Due to their large mass, passive shields for large volume habitable modules are no longer an option and the attention is focused on the more complex, technologically challenging active systems. Among the possible solutions, the most promising is based on huge superconducting coils having a bending power sufficient to deflect out of the habitat charged particles with kinetic energy in the order of 1 GeV. Toroidal magnet systems based wound with Ti clad MgB2 conductor is proposed and described.

  20. Urinary bromide and breathing zone concentrations of 1-bromopropane from workers exposed to flexible foam spray adhesives.

    PubMed

    Hanley, K W; Petersen, M; Curwin, B D; Sanderson, W T

    2006-08-01

    1-Bromopropane (1-BP) has been marketed as an alternative for ozone depleting solvents and suspect carcinogens and is in aerosol products, adhesives and solvents used for metal, precision and electronics cleaning. Toxicity of 1-BP is poorly understood, but it may be a neurologic, reproductive and hematologic toxin. Sparse exposure information prompted this exposure assessment study using air sampling, and measurement of urinary metabolites. Mercapturic acid conjugates are excreted in urine from 1-BP metabolism involving removal of bromide (Br) from the propyl group. One research objective was to evaluate the utility of urinary Br analysis for assessing 1-BP exposure using a relatively inexpensive, commercially available method. Complete 48 h urine specimens were obtained from 30 workers on two consecutive days at two facilities using 1-BP adhesives to construct polyurethane foam seat cushions and from seven unexposed control subjects. All of the workers' urine was collected into composite samples representing three daily time intervals (at work; after work but before bedtime; and upon wake-up) and analyzed for Br ion by inductively coupled plasma-mass spectrometry. Full-shift breathing zone samples were collected for 1-BP on Anasorb carbon molecular sieve sorbent tubes and analyzed by gas chromatography-flame ionization detection via NIOSH method 1025. Geometric mean (GM) breathing zone concentrations of 1-BP were 92 parts per million (p.p.m.) for adhesive sprayers and 11 p.p.m. for other jobs. For sprayers, urinary Br concentrations ranged from 77 to 542 milligrams per gram of creatinine [mg (g-cr)(-1)] at work; from 58 to 308 mg (g-cr)(-1) after work; and from 46 to 672 mg (g-cr)(-1) in wake-up samples. Pre-week urinary Br concentrations for sprayers were substantially higher than for the non-sprayers and controls, with GMs of 102, 31 and 3.8 mg (g-cr)(-1), respectively. An association of 48 h urinary Br concentration with 1-BP exposure was statistically significant (r(2) = 0.89) for all jobs combined. This study demonstrates that urinary elimination is an important excretion pathway for 1-BP metabolism, and Br may be a useful biomarker of exposure. PMID:16698849

  1. Characterization of Peptide-Oligonucleotide Heteroconjugates by Mass Spectrometry

    E-print Network

    Jensen, Ole N.; Kulkarni, Sandhya; Aldrich, Jane V.; Barofsky, Douglas F.

    1996-09-15

    . The chromatography system consisted of a Perkin-Elmer ABI 140B syringe pump, a 1 mm × 250 mm, 5 µm particle, 300 Å pore, Vydac C18 column (The Separations Group), and an ABI/Kratos Model 783 UV-detector equipped with a microbore flow cell (1 µl dead volume... was produced from 30 consecutive pulses of 355 nm photons from a Nd:YAG laser (Spectra Physics GCR-11). Signals from matrix ions or ions from various standards added to the sample were used for mass calibration. Prior to being mass analyzed, aliquots from...

  2. [Individual characteristics of correction of the cosmonauts' vegetative status with a method of adaptive biofeedback

    NASA Technical Reports Server (NTRS)

    Kornilova, L. N.; Cowings, P.; Arlashchenko, N. I.; Korneev, D. Iu; Sagalovich, S. V.; Sarantseva, A. V.; Toscano, W.; Kozlovskaia, I. B.

    2003-01-01

    The ability of 4 cosmonauts to voluntarily control their physiological parameters during the standing test was evaluated following a series of the adaptive feedback (AF) training sessions. Vegetative status of the cosmonauts during voluntary "relaxation" and "straining" was different when compared with its indices determined before these sessions. In addition, there was a considerable individual variability in the intensity and direction of the AF effects, and the range of parameters responding to AF. It was GCR which was the easiest one for the AF control.

  3. An Experience Improving Intrusion Detection Systems False Alarm Ratio by Using Honeypot

    E-print Network

    Bentahar, Jamal

    . GIDO is the specification of messaging as its encoded content is either some particular occurrence the intrusion detection system, generates events based on the traffic thereon and handovers them in GIDO format

  4. SIMULATING SUB-DECADAL CHANNEL MORPHOLOGIC CHANGE IN EPHEMERAL STREAM NETWORKS

    EPA Science Inventory

    A distributed watershed model was modified to simulate cumulative channel morphologic change from multiple runoff events in ephemeral stream networks. The model incorporates the general design of the event-based Kinematic Runoff and" Erosion Model (KINEROS), which describes t...

  5. Cyber-Physical Systems and Events

    Microsoft Academic Search

    Carolyn L. Talcott

    2008-01-01

    This paper discusses event-based semantics in the context of the emerging concept of Cyber Physical Systems and describes two related formal models concerning policy-based\\u000a coordination and Interactive Agents.

  6. Event-by-event Simulation of Quantum Cryptography Protocols

    E-print Network

    Shuang Zhao; Hans De Raedt

    2007-08-13

    We present a new approach to simulate quantum cryptography protocols using event-based processes. The method is validated by simulating the BB84 protocol and the Ekert protocol, both without and with the presence of an eavesdropper.

  7. Changes in Tropical Cyclone Behavior Changes in the Upper Air Environment

    E-print Network

    Kuligowski, Bob

    Events Left Turns -------------------- 79 Events Eye Structure Changes ----- 47 Events Intensification Events Base Surges ------------------ 73 Events Dry Air Effects -------------- 50 Events Adjacent System Behavior Right Turns ----------------- 153 Events Left Turns -------------------- 79 Events Eye Structure

  8. Real-Time Light Curve Classification Dan Cervone

    E-print Network

    Wolfe, Patrick J.

    (short-period variable stars), eclipsing binary systems (EB), RR Lyrae, and long period variables (LPV). Non-periodic, stochastic sources: Be, Quasars. Event-based: Supernovae, microlensing events. (There

  9. Design of Two RadWorks Storm Shelters for Solar Particle Event Shielding

    NASA Technical Reports Server (NTRS)

    Simon, Matthew; Cerro, Jeffery; Latorella, Kara; Clowdsley, Martha; Watson, Judith; Albertson, Cindy; Norman, Ryan; Le Boffe, Vincent; Walker, Steven

    2014-01-01

    In order to enable long-duration human exploration beyond low-Earth orbit, the risks associated with exposure of astronaut crews to space radiation must be mitigated with practical and affordable solutions. The space radiation environment beyond the magnetosphere is primarily a combination of two types of radiation: galactic cosmic rays (GCR) and solar particle events (SPE). While mitigating GCR exposure remains an open issue, reducing astronaut exposure to SPEs is achievable through material shielding because they are made up primarily of medium-energy protons. In order to ensure astronaut safety for long durations beyond low-Earth orbit, SPE radiation exposure must be mitigated. However, the increasingly demanding spacecraft propulsive performance for these ambitious missions requires minimal mass and volume radiation shielding solutions which leverage available multi-functional habitat structures and logistics as much as possible. This paper describes the efforts of NASA's RadWorks Advanced Exploration Systems (AES) Project to design two minimal mass SPE radiation shelter concepts leveraging available resources: one based upon reconfiguring habitat interiors to create a centralized protection area and one based upon augmenting individual crew quarters with waterwalls and logistics. Discussion items include the design features of the concepts, a radiation analysis of their implementations, an assessment of the parasitic mass of each concept, and the result of a human in the loop evaluation performed to drive out design and operational issues.

  10. Space Exploration: Where We Have Been, Where We Are and Where We Are Going: A Human Perspective

    NASA Technical Reports Server (NTRS)

    Tripathi, R. K.

    2005-01-01

    NASA is moving forward towards the agency's new vision for space exploration in the 21st Century encompassing a broad range of human and robotic missions including missions to Moon, Mars and beyond. Exposure from the hazards of severe space radiation in deep space long duration missions is the show stopper. Langley has developed state-of-the-art radiation protection and shielding technology for space missions. The payload penalty demands a very stringent requirement on the design of the spacecrafts for human deep space missions. The exploration beyond low Earth orbit (LEO) to enable routine access to more interesting regions of space will require protection from the hazards of the accumulated exposures of space radiation, Galactic Cosmic Rays (GCR) and Solar Particle Events (SPE), and minimizing the production of secondary radiation is a great advantage. The better understanding of radiation environment (GCR & SPE) and their interaction is a key to the success of the program due to the vital role and importance of cosmic rays for space missions.

  11. Monte Carlo Analysis of Pion Contribution to Absorbed Dose from Galactic Cosmic Rays

    NASA Technical Reports Server (NTRS)

    Aghara, S.K.; Battnig, S.R.; Norbury, J.W.; Singleterry, R.C.

    2009-01-01

    Accurate knowledge of the physics of interaction, particle production and transport is necessary to estimate the radiation damage to equipment used on spacecraft and the biological effects of space radiation. For long duration astronaut missions, both on the International Space Station and the planned manned missions to Moon and Mars, the shielding strategy must include a comprehensive knowledge of the secondary radiation environment. The distribution of absorbed dose and dose equivalent is a function of the type, energy and population of these secondary products. Galactic cosmic rays (GCR) comprised of protons and heavier nuclei have energies from a few MeV per nucleon to the ZeV region, with the spectra reaching flux maxima in the hundreds of MeV range. Therefore, the MeV - GeV region is most important for space radiation. Coincidentally, the pion production energy threshold is about 280 MeV. The question naturally arises as to how important these particles are with respect to space radiation problems. The space radiation transport code, HZETRN (High charge (Z) and Energy TRaNsport), currently used by NASA, performs neutron, proton and heavy ion transport explicitly, but it does not take into account the production and transport of mesons, photons and leptons. In this paper, we present results from the Monte Carlo code MCNPX (Monte Carlo N-Particle eXtended), showing the effect of leptons and mesons when they are produced and transported in a GCR environment.

  12. Radiation Effects and Protection for Moon and Mars Missions

    NASA Technical Reports Server (NTRS)

    Parnell, Thomas A.; Watts, John W., Jr.; Armstrong, Tony W.

    1998-01-01

    Manned and robotic missions to the Earth's moon and Mars are exposed to a continuous flux of Galactic Cosmic Rays (GCR) and occasional, but intense, fluxes of Solar Energetic Particles (SEP). These natural radiations impose hazards to manned exploration, but also present some constraints to the design of robotic missions. The hazards to interplanetary flight crews and their uncertainties have been studied recently by a National Research Council Committee (Space Studies Board 1996). Considering the present uncertainty estimates, thick spacecraft shielding would be needed for manned missions, some of which could be accomplished with onboard equipment and expendables. For manned and robotic missions, the effects of radiation on electronics, sensors, and controls require special consideration in spacecraft design. This paper describes the GCR and SEP particle fluxes, secondary particles behind shielding, uncertainties in radiobiological effects and their impact on manned spacecraft design, as well as the major effects on spacecraft equipment. The principal calculational tools and considerations to mitigate the radiation effects are discussed, and work in progress to reduce uncertainties is included.

  13. Does the space environment affect the ecosphere?

    NASA Astrophysics Data System (ADS)

    Schwadron, Nathan A.; Spence, Harlan E.; Came, Rosemarie

    2011-09-01

    The Sun is now emerging from a deep and protracted solar minimum, when the power, pressure, flux, and magnetic flux of solar wind were at their lowest levels [McComas et al., 2008; Schwadron and McComas, 2008; Connick et al., 2011]. Because of an anomalously weak heliospheric magnetic field and low solar wind pressure, galactic cosmic rays (GCRs)—protons, electrons, and ionized nuclei of elements accelerated to high energies—achieved the highest fluxes observed in the space age (Figure 1) [Mewaldt et al., 2010]. Related observations have shown remarkably rapid changes in the fluxes of energetic neutral atoms (ENAs) used by NASA's Interstellar Boundary Explorer mission to image the global heliosphere surrounding the solar system [McComas et al., 2010]. These changes in ENAs are caused by decreasing solar wind pressure. Does the recent anomalous deep solar minimum hint at larger changes in store? And how do changing GCR fluxes and conditions on the Sun influence Earth's ecosphere? Given the fact that GCR radiation can damage living tissue, causing cellular mutagenesis, the changing state of the Sun may have serious implications for life on the planet.

  14. Yeast Assay Highlights the Intrinsic Genomic Instability of Human PML Intron 6 over Intron 3 and the Role of Replication Fork Proteins

    PubMed Central

    Chanet, Roland; Kienda, Guy; Heneman-Masurel, Amélie; Vernis, Laurence; Cassinat, Bruno; Guardiola, Philippe; Fenaux, Pierre; Chomienne, Christine; Huang, Meng-Er

    2015-01-01

    Human acute promyelocytic leukemia (APL) is characterized by a specific balanced translocation t(15;17)(q22;q21) involving the PML and RARA genes. In both de novo and therapy-related APL, the most frequent PML breakpoints are located within intron 6, and less frequently in intron 3; the precise mechanisms by which these breakpoints arise and preferentially in PML intron 6 remain unsolved. To investigate the intrinsic properties of the PML intron sequences in vivo, we designed Saccharomyces cerevisiae strains containing human PML intron 6 or intron 3 sequences inserted in yeast chromosome V and measured gross chromosomal rearrangements (GCR). This approach provided evidence that intron 6 had a superior instability over intron 3 due to an intrinsic property of the sequence and identified the 3’ end of intron 6 as the most susceptible to break. Using yeast strains invalidated for genes that control DNA replication, we show that this differential instability depended at least upon Rrm3, a DNA helicase, and Mrc1, the human claspin homolog. GCR induction by hydrogen peroxide, a general genotoxic agent, was also dependent on genetic context. We conclude that: 1) this yeast system provides an alternative approach to study in detail the properties of human sequences in a genetically controlled situation and 2) the different susceptibility to produce DNA breaks in intron 6 versus intron 3 of the human PML gene is likely due to an intrinsic property of the sequence and is under replication fork genetic control. PMID:26053431

  15. Space Radiation: The Number One Risk to Astronaut Health beyond Low Earth Orbit

    PubMed Central

    Chancellor, Jeffery C.; Scott, Graham B. I.; Sutton, Jeffrey P.

    2014-01-01

    Projecting a vision for space radiobiological research necessitates understanding the nature of the space radiation environment and how radiation risks influence mission planning, timelines and operational decisions. Exposure to space radiation increases the risks of astronauts developing cancer, experiencing central nervous system (CNS) decrements, exhibiting degenerative tissue effects or developing acute radiation syndrome. One or more of these deleterious health effects could develop during future multi-year space exploration missions beyond low Earth orbit (LEO). Shielding is an effective countermeasure against solar particle events (SPEs), but is ineffective in protecting crew members from the biological impacts of fast moving, highly-charged galactic cosmic radiation (GCR) nuclei. Astronauts traveling on a protracted voyage to Mars may be exposed to SPE radiation events, overlaid on a more predictable flux of GCR. Therefore, ground-based research studies employing model organisms seeking to accurately mimic the biological effects of the space radiation environment must concatenate exposures to both proton and heavy ion sources. New techniques in genomics, proteomics, metabolomics and other “omics” areas should also be intelligently employed and correlated with phenotypic observations. This approach will more precisely elucidate the effects of space radiation on human physiology and aid in developing personalized radiological countermeasures for astronauts. PMID:25370382

  16. Charged Particle Measurements with the Mars Science Laboratory's Radiation Assessment Detector (MSL/RAD)

    NASA Astrophysics Data System (ADS)

    Ehresmann, B.; Hassler, D.; Zeitlin, C. J.; Kohler, J.; Wimmer-Schweingruber, R. F.; Appel, J. K.; Boehm, E.; Böttcher, S. I.; Brinza, D. E.; Burmeister, S.; Guo, J.; Lohf, H.; Martin-Garcia, C.; Matthiae, D.; Posner, A.; Rafkin, S. C.; Reitz, G.

    2014-12-01

    Since the Curiosity rover's landing in Gale crater on the surface of Mars, the Radiation Assessment Detector (RAD) on board the rover has been conducting the first-ever measurements of the Martian surface radiation field. This field is induced by Galactic Cosmic Rays (GCRs) and their interactions with the atoms of the Martian atmosphere and soil. Furthermore, sporadic Solar Energetic Particle (SEP) events can lead to large, but short-term enhancements in the intensity of the radiation field. A large part of the radiation environment is made up of charged particles, e.g., ions and their isotopes, electrons, and positrons amongst others. There are mainly two factors influencing the surface radiation field: the modulation of the incoming GCR flux due to the solar magnetic field correlating with the solar cycle; the amount of atmospheric column mass above Gale crater resulting in changes of GCR penetration depth into the atmosphere, as well as influencing the secondary particle production rate. Here, we focus on the temporal evolution of the radiation environment since the landing, analyzing changes in the measured particle spectra for different phases in the Martian seasonal cycle and solar activity. Furthermore, we present enhancements in the proton flux during directly observed SEP events.

  17. The Earth climate and life evolution response to cosmic radiation enhancement arising from reversals and excursions of geomagnetic field

    NASA Astrophysics Data System (ADS)

    Kuznetsova, N.

    Climate abrupt warming as well as biologic evolutionary events in respect to fauna and human evolution are shown to originate during reversals and excursions of geomagnetic field when the geomagnetic field loses a lot in its module value and consequently in its protective characteristics making galactic cosmic rays GCR and solar protons penetration into the Earth atmosphere possible Usually preceded by climate cooling and populations reduction reversals and excursions stimulate evolutionary genetic mutations generated by intense radiation and climate abrupt warming resulted from destruction of stratospheric aerosols by GCR Favorable environment conditions on new features and species origin For example it was Gauss-Matuyama reversal 2 3 Myr to make for Hominid evolutionary mutations and for distinctly new species Homo erectus origin The evolutionary events and climate shifts appear explicable on the context of the fundamentally new model of the geomagnetic field generation based on hypothesis of the hot Earth and the theory of the Earth magnetic poles drift throughout reversals and excursions theory

  18. Shielding experiments with high-energy heavy ions for spaceflight applications

    NASA Astrophysics Data System (ADS)

    Zeitlin, C.; Guetersloh, S.; Heilbronn, L.; Miller, J.; Elkhayari, N.; Empl, A.; LeBourgeois, M.; Mayes, B. W.; Pinsky, L.; Christl, M.; Kuznetsov, E.

    2008-07-01

    Mitigation of radiation exposures received by astronauts on deep-space missions must be considered in the design of future spacecraft. The galactic cosmic rays (GCR) include high-energy heavy ions, many of which have ranges that exceed the depth of shielding that can be launched in realistic scenarios. Some of these ions are highly ionizing (producing a high dose per particle) and for some biological endpoints are more damaging per unit dose than sparsely ionizing radiation. The principal physical mechanism by which the dose and dose equivalent delivered by these particles can be reduced is nuclear fragmentation, the result of inelastic collisions between nuclei in the hull of the spacecraft and/or other materials. These interactions break the incident ions into lighter, less ionizing and less biologically effective particles. We have previously reported the tests of shielding effectiveness using many materials in a 1 GeV nucleon-1 56Fe beam, and also reported results using a single polyethylene (CH2) target in a variety of beam ions and energies up to 1 GeV nucleon-1. An important, but tentative, conclusion of those studies was that the average behavior of heavy ions in the GCR would be better simulated by heavy beams at energies above 1 GeV nucleon-1. Following up on that work, we report new results using beams of 12C, 28Si and 56Fe, each at three energies, 3, 5 and 10 GeV nucleon-1, on carbon, polyethylene, aluminium and iron targets.

  19. LET spectra measurements of charged particles in the P0006 experiment on LDEF

    NASA Technical Reports Server (NTRS)

    Benton, E. V.; Csige, I.; Oda, K.; Henke, R. P.; Frank, A. L.; Benton, E. R.; Frigo, L. A.; Parnell, T. A.; Watts, J. W., Jr.; Derrickson, J. H.

    1993-01-01

    Measurements are under way of the charged particle radiation environment of the Long Duration Exposure Facility (LDEF) satellite using stacks of plastic nuclear track detectors (PNTD's) placed in different locations of the satellite. In the initial work the charge, energy, and linear energy transfer (LET) spectra of charged particles were measured with CR-39 double layer PNTD's located on the west side of the satellite (Experiment P0006). Primary and secondary stopping heavy ions were measured separately from the more energetic particles. Both trapped and galactic cosmic ray (GCR) particles are included, with the latter component being dominated by relativistic iron particles. The results from the P0006 experiment will be compared with similar measurements in other locations on LDEF with different orientation and shielding conditions. The remarkably detailed investigation of the charged particle radiation environment of the LDEF satellite will lead to a better understanding of the radiation environment of the Space Station Freedom. It will enable more accurate prediction of single event upsets (SEU's) in microelectronics and, especially, more accurate assessment of the risk - contributed by different components of the radiation field (GCR's, trapped protons, secondaries and heavy recoils, etc.) - to the health and safety of crew members.

  20. Overview of Atmospheric Ionizing Radiation (AIR) Research: SST - Present

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Goldhagen, P.; Rafnsson, V.; Clem, J. M.; DeAngelis, G.; Friedberg, W.

    2002-01-01

    The Supersonic Transport (SST) program, proposed in 1961, first raised concern for the exposure of pregnant occupants by solar energetic particles (SEP), and neutrons were suspected to have a main role in particle propagation deep into the atmosphere. An eight-year flight program confirmed the role of SEP as a significant hazard and of the neutrons as contributing over half of the galactic cosmic ray (GCR) exposures, with the largest contribution from neutrons above 10 MeV. The FAA Advisory Committee on the Radiobiological Aspects of the SST provided operational requirements. The more recent (1990) lowering of recommended exposure limits by the International Commission on Radiological Protection with the classification of aircrew as "radiation workers" renewed interest in GCR background exposures at commercial flight altitudes and stimulated epidemiological studies in Europe, Japan, Canada and the USA. The proposed development of a High Speed Civil Transport (HSCT) required validation of the role of high-energy neutrons, and this resulted in ER-2 flights at solar minimum (June 1997) and studies on effects of aircraft materials on interior exposures. Recent evaluation of health outcomes of DOE nuclear workers resulted in legislation for health compensation in year 2000 and recent European aircrew epidemiological studies of health outcomes bring renewed interest in aircraft radiation exposures. As improved radiation models become available, it is imperative that a corresponding epidemiological program of US aircrew be implemented.

  1. ACTINIDE AND ULTRA-HEAVY ABUNDANCES IN THE LOCAL GALACTIC COSMIC RAYS: AN ANALYSIS OF THE RESULTS FROM THE LDEF ULTRA-HEAVY COSMIC-RAY EXPERIMENT

    SciTech Connect

    Donnelly, J. [Dublin Institute of Technology (DIT), School of Physics, Kevin Street, Dublin 8 (Ireland); Thompson, A.; O'Sullivan, D.; Daly, J.; Drury, L. [School of Cosmic Physics, Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland); Domingo, V.; Wenzel, K.-P. [European Space Research and Technology Centre (ESTEC), Keplerlaan 1, Postbus 299, 2200 AG Noordwijk (Netherlands)

    2012-03-01

    The LDEF Ultra-Heavy Cosmic-Ray Experiment (UHCRE) detected Galactic cosmic rays (GCRs) of charge Z {>=} 70 in Earth orbit with an exposure factor of 170 m{sup 2} sr yr, much larger than any other experiment. The major results include the first statistically significant uniform sample of GCR actinides with 35 events passing quality cuts, evidence for the existence of transuranic nuclei in the GCR with one {sub 96}Cm candidate event, and a low {sub 82}Pb/{sub 78}Pt ratio consistent with other experiments. The probability of the existence of a transuranic component is estimated as 96%, while the most likely {sub 92}U/{sub 90}Th ratio is found to be 0.4 within a wide 70% confidence interval ranging from 0 to 0.96. Overall, the results are consistent with a volatility-based acceleration bias and source material which is mainly ordinary interstellar medium material with some recent contamination by freshly synthesized material. Uncertainty in the key {sub 92}U/{sub 90}Th ratio is dominated by statistical errors resulting from the small sample size and any improved determination will thus require an experiment with a substantially larger exposure factor than the UHCRE.

  2. Comparisons Between Model Predictions and Spectral Measurements of Charged and Neutral Particles on the Martian Surface

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee Y.; Cucinotta, Francis A.; Zeitlin, Cary; Hassler, Donald M.; Ehresmann, Bent; Rafkin, Scot C. R.; Wimmer-Schweingruber, Robert F.; Boettcher, Stephan; Boehm, Eckart; Guo, Jingnan; Koehler, Jan; Martin, Cesar; Reitz, Guenther; Posner, Arik

    2914-01-01

    Detailed measurements of the energetic particle radiation environment on the surface of Mars have been made by the Radiation Assessment Detector (RAD) on the Curiosity rover since August 2012. RAD is a particle detector that measures the energy spectrum of charged particles (10 to approx. 200 MeV/u) and high energy neutrons (approx 8 to 200 MeV). The data obtained on the surface of Mars for 300 sols are compared to the simulation results using the Badhwar-O'Neill galactic cosmic ray (GCR) environment model and the high-charge and energy transport (HZETRN) code. For the nuclear interactions of primary GCR through Mars atmosphere and Curiosity rover, the quantum multiple scattering theory of nuclear fragmentation (QMSFRG) is used. For describing the daily column depth of atmosphere, daily atmospheric pressure measurements at Gale Crater by the MSL Rover Environmental Monitoring Station (REMS) are implemented into transport calculations. Particle flux at RAD after traversing varying depths of atmosphere depends on the slant angles, and the model accounts for shielding of the RAD "E" dosimetry detector by the rest of the instrument. Detailed comparisons between model predictions and spectral data of various particle types provide the validation of radiation transport models, and suggest that future radiation environments on Mars can be predicted accurately. These contributions lend support to the understanding of radiation health risks to astronauts for the planning of various mission scenarios

  3. Rapid assessment of radiobiological doses for terrestrial and interplanetary space missions.

    PubMed

    Melkonian, G; Bourrieau, J

    1994-11-01

    This paper presents the doses levels expected in orbits in chart form, covering the range 300-800 km of altitude and 0-90 degrees of inclination behind shieldings similar to the Hermes spacecraft and the EVA spacesuit matter distributions. These charts allow users to rapidly find the radiobiological dose received in the most critical organs of the human body either in normal situations or during a large solar event. Outside the magnetosphere, during interplanetary or lunar missions, when the dose received during crossing of the radiation belts become negligible, the dose is due to galactic cosmic rays (GCR) and solar flares. The correct radiobiological assessment of the components of this radiation field becomes a major problem. On the Moon a permanent ground-based station can be shielded by lunar materials against meteoroids and radiations. The radiobiological hazard, essentially linked to the solar flare risk during the transfer phase and the extra-station activities, may be solved by mission planning. For interplanetary flights the problem comes from both increased risk of solar events and from the continuous exposure to GCR. These energetic particles cannot be easily stopped by shieldings; cost considerations imply that more effective materials must be used. Impact on the vehicle design and the mission planning is important. PMID:11538449

  4. Pathologic Role of Stressed-Induced Glucocorticoids in Drug-Induced Liver Injury in Mice

    PubMed Central

    Masson, Mary Jane; Collins, Lindsay A.; Carpenter, Leah D.; Graf, Mary L.; Ryan, Pauline M.; Bourdi, Mohammed; Pohl, Lance R.

    2010-01-01

    We previously reported that acetaminophen (APAP)-induced liver injury (AILI) in mice is associated with a rise in serum levels of the glucocorticoid (GC), corticosterone. In the current study, we provide evidence that endogenous GC play a pathologic role in AILI. Specifically, pretreatment of mice with the GC receptor (GCR) inhibitor, RU486 (mifepristrone), protected normal but not adrenalectomized mice from AILI, while pretreatment with dexamethasone, a synthetic GC, exacerbated AILI. RU486 did not affect the depletion of whole liver reduced GSH or the formation of APAP-protein adducts. It also had no effects on the formation of reactive oxygen species or the depletion of mitochondrial GSH or ATP. While RU486 pretreatment also protected against halothane-induced liver injury, it exacerbated concanavalin A (ConA)- and carbon tetrachloride (CCl4)-induced liver injury, demonstrating the complexity of GC effects in different types of liver injury. Conclusion: These results suggest that under certain conditions, elevated levels of GC might represent a previously unappreciated risk factor for liver injury caused by APAP and other drugs through the diverse biological processes regulated by GCR. PMID:20510877

  5. Human exposure to space radiation: role of primary and secondary particles.

    PubMed

    Trovati, S; Ballarini, F; Battistoni, G; Cerutti, F; Fassò, A; Ferrari, A; Gadioli, E; Garzelli, M V; Mairani, A; Ottolenghi, A; Paretzke, H G; Parini, V; Pelliccioni, M; Pinsky, L; Sala, P R; Scannicchio, D; Zankl, M

    2006-01-01

    Human exposure to space radiation implies two kinds of risk, both stochastic and deterministic. Shielding optimisation therefore represents a crucial goal for long-term missions, especially in deep space. In this context, the use of radiation transport codes coupled with anthropomorphic phantoms allows to simulate typical radiation exposures for astronauts behind different shielding, and to calculate doses to different organs. In this work, the FLUKA Monte Carlo code and two phantoms, a mathematical model and a voxel model, were used, taking the Galactic Cosmic Rays (GCR) spectra from the model of Badhwar and O'Neill. The time integral spectral proton fluence of the August 1972 Solar Particle Event (SPE) was represented by an exponential function. For each aluminium shield thickness, besides total doses the contributions from primary and secondary particles for different organs and tissues were calculated separately. More specifically, organ-averaged absorbed doses, dose equivalents and a form of 'biological dose', defined on the basis of initial (clustered) DNA damage, were calculated. As expected, the SPE doses dramatically decreased with increasing shielding, and doses in internal organs were lower than in skin. The contribution of secondary particles to SPE doses was almost negligible; however it is of note that, at high shielding (10 g cm(-2)), most of the secondaries are neutrons. GCR organ doses remained roughly constant with increasing Al shielding. In contrast to SPE results, for the case of cosmic rays, secondary particles accounted for a significant fraction of the total dose. PMID:17151013

  6. Lunar radiation environment: a study by using Kaguya gamma-ray spectrometer and Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Kobayashi, Shingo; Hayatsu, Kanako; Uchihori, Yukio; Hareyama, Makoto; Hasebe, Nobuyuki; Fujibayashi, Yukari

    2012-07-01

    We have continued to improve the estimation of radiation dose on the Moon based on observation by remote sensing and calculation of the transportation of cosmic-ray particles in the lunar materials in order to provide basic data for a future manned lunar exploration. On the lunar surface, the dose of primary galactic cosmic rays (pGCR) is the most significant and the contributions of neutrons and gamma rays are relatively small and are approximately 10% and 1% of that of pGCR, respectively. However, these percentages are changed by use of thick shieldings and also geographical feature of the lunar surface, such as margin of a huge boulder, bottom of a pit, inside of a possible lava tube. In this case, the dose by pGCRs is moderated and the contributions of neutrons and gamma rays relatively increase. Here, we show the recent estimation of spatial variation of the lunar dose due to gamma ray and neutrons measured by Kaguya gamma-ray spectrometer. The energy spectrum of gamma rays from the lunar surface are precisely measured by a germanium (Ge) gamma-ray spectrometer onboard the Japanese lunar orbiter (Kaguya/SELENE). The flux of fast neutrons from the lunar surface was also measured by detecting the characteristic gamma rays due to the neutron inelastic reaction with the Ge of the spectrometer, that is 72Ge(n, n'g)72Ge. The estimation of radiation dose on the Moon based on Monte Carlo simulation will also be presented.

  7. Low dose radiation hypersensitivity and clustered DNA damages in human fibroblasts exposed to low dose and dose rate protons or 137CS y-rays

    SciTech Connect

    Bennett P. V.; Bennett, P.V.; Keszenman, D.J.; Johnson, A.M.; Sutherland, B.M.; Wilson, P.F.

    2013-05-14

    Effective radioprotection for human space travelers hinges upon understanding the individual properties of charged particles. A significant fraction of particle radiation astronauts will encounter in space exploratory missions will come from high energy protons in galactic cosmic radiation (GCR) and/or possible exposures to lower energy proton flux from solar particle events (SPEs). These potential exposures present major concerns for NASA and others, in planning and executing long term space exploratory missions. We recently reported cell survival and transformation (acquisition of anchorage-independent growth in soft agar) frequencies in apparently normal NFF-28 primary human fibroblasts exposed to 0-30 cGy of 50MeV, 100MeV (SPE-like), or 1000 MeV (GCR-like) monoenergetic protons. These were modeled after 1989 SPE energies at an SPE-like low dose-rate (LDR) of 1.65 cGy/min or high dose rate (HDR) of 33.3 cGy/min delivered at the NASA Space Radiation Laboratory (NSRL) at BNL.

  8. Summary of Atmospheric Ionizing AIR Research: SST-Present

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Goldhagen, P.; Rafnsson, V.; deAngelis, G.; Friedberg, W.; Clem, J. M.

    2003-01-01

    The Supersonic Transport (SST) program, proposed in 1961, first raised concern for the exposure of pregnant occupants by solar energetic particles (SEP), and neutrons were suspected to have a main role in particle propagation deep into the atmosphere. An eight-year flight program confirmed the role of SEP as a significant hazard and of the neutrons as contributing over half of the galactic cosmic ray (GCR) exposures, with the largest contribution from neutrons above 10 MeV. The FAA Advisory Committee on the Radiobiological Aspects of the SST provided operational requirements. The more recent lowering of the radiation exposure limits by the International Commission on Radiological Protection with the classification of aircrew as radiation workers renewed interest in GCR background exposures at commercial flight altitudes and stimulated epidemiological studies in Europe, Japan, Canada and the USA. The proposed development of a High Speed Civil Transport (HSCT) required validation of the role of high-energy neutrons, and this resulted in ER-2 flights at solar minimum (June 1997) and studies on effects of aircraft materials on interior exposures. Recent evaluation of health outcomes of DOE nuclear workers resulted in legislation for health compensation in year 2000 and recent European aircrew epidemiological studies of health outcomes bring renewed interest in aircraft radiation exposures. As improved radiation models become available, it is imperative that a corresponding epidemiological program of US aircrew be implemented.

  9. Synchronized Northern Hemisphere climate change and solar magnetic cycles during the Maunder Minimum

    PubMed Central

    Yamaguchi, Yasuhiko T.; Yokoyama, Yusuke; Miyahara, Hiroko; Sho, Kenjiro; Nakatsuka, Takeshi

    2010-01-01

    The Maunder Minimum (A.D. 1645–1715) is a useful period to investigate possible sun–climate linkages as sunspots became exceedingly rare and the characteristics of solar cycles were different from those of today. Here, we report annual variations in the oxygen isotopic composition (?18O) of tree-ring cellulose in central Japan during the Maunder Minimum. We were able to explore possible sun–climate connections through high-temporal resolution solar activity (radiocarbon contents; ?14C) and climate (?18O) isotope records derived from annual tree rings. The tree-ring ?18O record in Japan shows distinct negative ?18O spikes (wetter rainy seasons) coinciding with rapid cooling in Greenland and with decreases in Northern Hemisphere mean temperature at around minima of decadal solar cycles. We have determined that the climate signals in all three records strongly correlate with changes in the polarity of solar dipole magnetic field, suggesting a causal link to galactic cosmic rays (GCRs). These findings are further supported by a comparison between the interannual patterns of tree-ring ?18O record and the GCR flux reconstructed by an ice-core 10Be record. Therefore, the variation of GCR flux associated with the multidecadal cycles of solar magnetic field seem to be causally related to the significant and widespread climate changes at least during the Maunder Minimum. PMID:21076031

  10. Simulation of Earth-Moon-Mars Environments for the Assessment of Organ Doses

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee; Schwadron, Nathan; Townsend, Lawrence W.; Cucinotta, Francis A.

    2010-01-01

    Space radiation environments for historically large solar particle events (SPE) and galactic cosmic rays (GCR) at solar minimum and solar maximum are simulated in order to characterize exposures to radio-sensitive organs for missions to low-Earth orbit (LEO), moon, and Mars. Primary and secondary particles for SPE and GCR are transported through the respective atmosphere of Earth or Mars, space vehicle, and astronaut s body tissues using the HZETRN/QMSFRG computer code. In LEO, exposures are reduced compared to deep space because particles are deflected by the Earth s magnetic field and absorbed by the solid body of the Earth. Geomagnetic transmission function as a function of altitude was applied for the particle flux of charged particles, and the shift or the organ exposures to higher velocity or lower stopping powers compared to those in deep space were analyzed. In the transport through Mars atmosphere, a vertical distribution of atmospheric thickness was calculated from the temperature and pressure data of Mars Global Surveyor, and the directional cosine distribution was implemented to describe the spherically distributed atmospheric distance along the slant path at each altitude. The resultant directional shielding by Mars atmosphere at solar minimum and solar maximum was used for the particle flux simulation at various altitudes on the Martian surface. Finally, atmospheric shielding was coupled with vehicle and body shielding for organ dose estimates. We made predictions of radiation dose equivalents and evaluated acute symptoms at LEO, moon, and Mars at solar minimum and solar maximum.

  11. A comparative study of space radiation organ doses and associated cancer risks using PHITS and HZETRN

    NASA Astrophysics Data System (ADS)

    Bahadori, Amir A.; Sato, Tatsuhiko; Slaba, Tony C.; Shavers, Mark R.; Semones, Edward J.; Van Baalen, Mary; Bolch, Wesley E.

    2013-10-01

    NASA currently uses one-dimensional deterministic transport to generate values of the organ dose equivalent needed to calculate stochastic radiation risk following crew space exposures. In this study, organ absorbed doses and dose equivalents are calculated for 50th percentile male and female astronaut phantoms using both the NASA High Charge and Energy Transport Code to perform one-dimensional deterministic transport and the Particle and Heavy Ion Transport Code System to perform three-dimensional Monte Carlo transport. Two measures of radiation risk, effective dose and risk of exposure-induced death (REID) are calculated using the organ dose equivalents resulting from the two methods of radiation transport. For the space radiation environments and simplified shielding configurations considered, small differences (<8%) in the effective dose and REID are found. However, for the galactic cosmic ray (GCR) boundary condition, compensating errors are observed, indicating that comparisons between the integral measurements of complex radiation environments and code calculations can be misleading. Code-to-code benchmarks allow for the comparison of differential quantities, such as secondary particle differential fluence, to provide insight into differences observed in integral quantities for particular components of the GCR spectrum.

  12. A comparative study of space radiation organ doses and associated cancer risks using PHITS and HZETRN.

    PubMed

    Bahadori, Amir A; Sato, Tatsuhiko; Slaba, Tony C; Shavers, Mark R; Semones, Edward J; Van Baalen, Mary; Bolch, Wesley E

    2013-10-21

    NASA currently uses one-dimensional deterministic transport to generate values of the organ dose equivalent needed to calculate stochastic radiation risk following crew space exposures. In this study, organ absorbed doses and dose equivalents are calculated for 50th percentile male and female astronaut phantoms using both the NASA High Charge and Energy Transport Code to perform one-dimensional deterministic transport and the Particle and Heavy Ion Transport Code System to perform three-dimensional Monte Carlo transport. Two measures of radiation risk, effective dose and risk of exposure-induced death (REID) are calculated using the organ dose equivalents resulting from the two methods of radiation transport. For the space radiation environments and simplified shielding configurations considered, small differences (<8%) in the effective dose and REID are found. However, for the galactic cosmic ray (GCR) boundary condition, compensating errors are observed, indicating that comparisons between the integral measurements of complex radiation environments and code calculations can be misleading. Code-to-code benchmarks allow for the comparison of differential quantities, such as secondary particle differential fluence, to provide insight into differences observed in integral quantities for particular components of the GCR spectrum. PMID:24061091

  13. Improvement Accuracy of Assessment of Total Equivalent Dose Rate during Air Travel

    NASA Astrophysics Data System (ADS)

    Dorenskiy, Sergey; Minligareev, Vladimir

    For radiation safety on the classic flight altitudes 8-11 km is necessary to develop a methodology for calculating the total equivalent dose rate (EDR) to prevent excess exposure of passengers and crews of airliners. During development it became necessary to assess all components affecting the calculation of EDR Comprehensive analysis of the solution to this problem, based on the developed program basis, allowing to automate calculations , as well as on the assessment of the statistical data is introduced. The results have shown that: 1) Limiting accuracy of error of geomagnetic cutoff rigidity (GCR) in the period from 2005 to 2010 was 5% This error is not significant within the considered problems. 2) It is necessary to take into account seasonal variations of atmospheric parameters in the calculation of the EDR. The difference in the determination of dose rate can reach 31% Diurnal variations of atmospheric parameters are offered to consider to improve reliability of EDR estimates. 3) Introduction in the GCR calculations of additional parameters is necessary for reliability improvement and estimation accuracy of EDR on flight routs (Kp index of geomagnetic activity , etc.).

  14. A comparison of depth dependence of dose and linear energy transfer spectra in aluminum and polyethylene.

    PubMed

    Badhwar, G D; Cucinotta, F A

    2000-01-01

    A set of four tissue-equivalent proportional counters (TEPCs), with their detector heads at the centers of 0 (bare), 3, 7 and 9-inch-diameter aluminum spheres, were flown on Shuttle flight STS-89. Five such detectors at the centers of polyethylene spheres were flown 1 year earlier on STS-81. The results of dose-depth dependence for the two materials convincingly show the merits of using material rich in hydrogen to decrease the radiation exposure to the crew. A comparison of the calculated galactic cosmic radiation (GCR) absorbed dose and dose-equivalent rates using the radiation transport code HZETRN with nuclear fragmentation model NUCFRG2 and the measured GCR absorbed dose rates and dose-equivalent rates shows that they agree within root mean square (rms) error of 12.5 and 8.2%, respectively. However, there are significant depth-dependent differences in the linear energy transfer (LET) spectra. A comparison for trapped protons using the proton transport code BRYNTRN and the AP-8 MIN trapped-proton model shows a systematic bias, with the model underpredicting dose and dose-equivalent rates. These results show the need for improvements in the radiation transport and/or fragmentation models. PMID:10630971

  15. Time Profile of Cosmic Radiation Exposure During the EXPOSE-E Mission: The R3DE Instrument

    PubMed Central

    Horneck, Gerda; Häder, Donat-Peter; Schuster, Martin; Richter, Peter; Lebert, Michael; Demets, Rene

    2012-01-01

    Abstract The aim of this paper is to present the time profile of cosmic radiation exposure obtained by the Radiation Risk Radiometer-Dosimeter during the EXPOSE-E mission in the European Technology Exposure Facility on the International Space Station's Columbus module. Another aim is to make the obtained results available to other EXPOSE-E teams for use in their data analysis. Radiation Risk Radiometer-Dosimeter is a low-mass and small-dimension automatic device that measures solar radiation in four channels and cosmic ionizing radiation as well. The main results of the present study include the following: (1) three different radiation sources were detected and quantified—galactic cosmic rays (GCR), energetic protons from the South Atlantic Anomaly (SAA) region of the inner radiation belt, and energetic electrons from the outer radiation belt (ORB); (2) the highest daily averaged absorbed dose rate of 426 ?Gy d?1 came from SAA protons; (3) GCR delivered a much smaller daily absorbed dose rate of 91.1 ?Gy d?1, and the ORB source delivered only 8.6 ?Gy d?1. The analysis of the UV and temperature data is a subject of another article (Schuster et al., 2012). Key Words: Ionizing radiation—R3D—ISS. Astrobiology 12, 403–411. PMID:22680687

  16. EVALUATION OF ZERO-POWER, ELEVATED-TEMPERATURE MEASUREMENTS AT JAPAN’S HIGH TEMPERATURE ENGINEERING TEST REACTOR

    SciTech Connect

    John D. Bess; Nozomu Fujimoto; James W. Sterbentz; Luka Snoj; Atsushi Zukeran

    2011-03-01

    The High Temperature Engineering Test Reactor (HTTR) of the Japan Atomic Energy Agency (JAEA) is a 30 MWth, graphite-moderated, helium-cooled reactor that was constructed with the objectives to establish and upgrade the technological basis for advanced high-temperature gas-cooled reactors (HTGRs) as well as to conduct various irradiation tests for innovative high-temperature research. The core size of the HTTR represents about one-half of that of future HTGRs, and the high excess reactivity of the HTTR, necessary for compensation of temperature, xenon, and burnup effects during power operations, is similar to that of future HTGRs. During the start-up core physics tests of the HTTR, various annular cores were formed to provide experimental data for verification of design codes for future HTGRs. The experimental benchmark performed and currently evaluated in this report pertains to the data available for two zero-power, warm-critical measurements with the fully-loaded HTTR core. Six isothermal temperature coefficients for the fully-loaded core from approximately 340 to 740 K have also been evaluated. These experiments were performed as part of the power-up tests (References 1 and 2). Evaluation of the start-up core physics tests specific to the fully-loaded core (HTTR-GCR-RESR-001) and annular start-up core loadings (HTTR-GCR-RESR-002) have been previously evaluated.

  17. ACCELERATION OF GALACTIC COSMIC RAYS IN THE INTERSTELLAR MEDIUM

    SciTech Connect

    Fisk, L. A.; Gloeckler, G., E-mail: lafisk@umich.edu [Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109-2143 (United States)

    2012-01-10

    Challenges have arisen to diffusive shock acceleration as the primary means to accelerate galactic cosmic rays (GCRs) in the interstellar medium. Diffusive shock acceleration is also under challenge in the heliosphere, where at least the simple application of diffusive shock acceleration cannot account for observations. In the heliosphere, a new acceleration mechanism has been invented-a pump mechanism, driven by ambient turbulence, in which particles are pumped up in energy out of a low-energy core particle population through a series of adiabatic compressions and expansions-that can account for observations not only at shocks but in quiet conditions in the solar wind and throughout the heliosheath. In this paper, the pump mechanism is applied to the acceleration of GCRs in the interstellar medium. With relatively straightforward assumptions about the magnetic field in the interstellar medium, and how GCRs propagate in this field, the pump mechanism yields (1) the overall shape of the GCR spectrum, a power law in particle kinetic energy, with a break at the so-called knee in the GCR spectrum to a slightly steeper power-law spectrum. (2) The rigidity dependence of the H/He ratio observed from the PAMELA satellite instrument.

  18. Benchmark Analysis of Pion Contribution from Galactic Cosmic Rays

    NASA Technical Reports Server (NTRS)

    Aghara, Sukesh K.; Blattnig, Steve R.; Norbury, John W.; Singleterry, Robert C., Jr.

    2008-01-01

    Shielding strategies for extended stays in space must include a comprehensive resolution of the secondary radiation environment inside the spacecraft induced by the primary, external radiation. The distribution of absorbed dose and dose equivalent is a function of the type, energy and population of these secondary products. A systematic verification and validation effort is underway for HZETRN, which is a space radiation transport code currently used by NASA. It performs neutron, proton and heavy ion transport explicitly, but it does not take into account the production and transport of mesons, photons and leptons. The question naturally arises as to what is the contribution of these particles to space radiation. The pion has a production kinetic energy threshold of about 280 MeV. The Galactic cosmic ray (GCR) spectra, coincidentally, reaches flux maxima in the hundreds of MeV range, corresponding to the pion production threshold. We present results from the Monte Carlo code MCNPX, showing the effect of lepton and meson physics when produced and transported explicitly in a GCR environment.

  19. Modeling the variations of Dose Rate measured by RAD during the first MSL Martian year: 2012-2014

    E-print Network

    Jingnan Guo; Cary Zeitlin; Robert F. Wimmer-Schweingruber; Scot Rafkin; Donald M. Hassler; Arik Posner; Bernd Heber; Jan Koehler; Bent Ehresmann; Jan K. Appel; Eckart Boehm; Stephan Boettcher; Soenke Burmeister; David E. Brinza; Henning Lohf; Cesar Martin; H. Kahanpaeae; Guenther Reitz

    2015-07-13

    The Radiation Assessment Detector (RAD), on board Mars Science Laboratory's (MSL) rover Curiosity, measures the {energy spectra} of both energetic charged and neutral particles along with the radiation dose rate at the surface of Mars. With these first-ever measurements on the Martian surface, RAD observed several effects influencing the galactic cosmic ray (GCR) induced surface radiation dose concurrently: [a] short-term diurnal variations of the Martian atmospheric pressure caused by daily thermal tides, [b] long-term seasonal pressure changes in the Martian atmosphere, and [c] the modulation of the primary GCR flux by the heliospheric magnetic field, which correlates with long-term solar activity and the rotation of the Sun. The RAD surface dose measurements, along with the surface pressure data and the solar modulation factor, are analysed and fitted to empirical models which quantitatively demonstrate} how the long-term influences ([b] and [c]) are related to the measured dose rates. {Correspondingly we can estimate dose rate and dose equivalents under different solar modulations and different atmospheric conditions, thus allowing empirical predictions of the Martian surface radiation environment.

  20. An assessment of galactic cosmic radiation quality considering heavy ion track structures within the cellular environment

    NASA Astrophysics Data System (ADS)

    Craven, P. A.; Rycroft, M. J.

    Beyond the magnetic influence of the Earth, the flux of galactic cosmic radiation (GCR) represents a radiological concern for long-term manned space missions. Current concepts of radiation quality and equivalent dose are inadequate for accurately specifying the relative biological ``efficiency'' of low doses of such heavily ionising radiations, based as they are on the single parameter of Linear Energy Transfer (LET). Such methods take no account of the mechanisms, nor of the highly inhomogeneous spatial structure, of energy deposition in radiation tracks. DNA damage in the cell nucleus, which ultimately leads to the death or transformation of the cell, is usually initiated by electrons liberated from surrounding molecules by the incident projectile ion. The characteristics of these emitted ``delta-rays'', dependent primarily upon the charge and velocity of the ion, are considered in relation to an idealised representation of the cellular environment. Theoretically calculated delta-ray energy spectra are multiplied by a series of weighting algorithms designed to represent the potential for DNA insult in this environment, both in terms of the quantity and quality of damage. By evaluating the resulting curves, and taking into account the energy spectra of heavy ions in space, a relative measure of the biological relevance of the most abundant GCR species is obtained, behind several shielding configurations. It is hoped that this method of assessing the radiation quality of galactic cosmic rays will be of value when considering the safety of long-term manned space missions.

  1. Full Calculation of Clumpiness Boost factors for Antimatter Cosmic Rays in the light of \\LambdaCDM N-body simulation results

    E-print Network

    Lavalle, J; Maurin, D; Bi, X -J

    2007-01-01

    Anti-proton and positron Galactic cosmic ray (GCR) spectra are among the key targets for indirect detection of dark matter (DM). The boost factors, corresponding to an enhancement of the signal|linked to the clumpiness properties of the dark matter distribution|, have been taken as high as thousands in the past. The dramatic impact of these boost factors for indirect detection of antiparticles, for instance with the PAMELA satellite or the coming AMS-02 experiment, asks for their detailed calculation. We take into account the state-of-the-art results of high resolution N-body dark matter simulations to calculate the most likely energy dependent boost factors|linked to the GCR propagation properties|, for anti-protons and positrons. The results from extreme, but still possible, configurations of the clumpy dark matter component is also discussed. Starting from the mass and space distributions of sub-halos, the anti-proton and positron propagators are used to calculate the mean value and the variance of the boo...

  2. Systematic configuration and automatic tuning of neuromorphic systems

    Microsoft Academic Search

    Sadique Sheik; Fabio Stefanini; Emre Neftci; Elisabetta Chicca; Giacomo Indiveri

    2011-01-01

    In the past recent years several research groups have proposed neuromorphic Very Large Scale Integration (VLSI) devices that implement event-based sensors or bio- physically realistic networks of spiking neurons. It has been argued that these devices can be used to build event-based systems, for solving real-world applications in real-time, with efficiencies and robustness that cannot be achieved with conven- tional

  3. Evaluation of the new radiation belt AE9/AP9/SPM model for a cislunar mission

    NASA Astrophysics Data System (ADS)

    Badavi, Francis F.; Walker, Steven A.; Santos Koos, Lindsey M.

    2014-09-01

    Space mission planners continue to experience challenges associated with human space flight. Concerned with the omnipresence of harmful ionizing radiation in space, at the mission design stage, mission planners must evaluate the amount of exposure the crew of a spacecraft is subjected to during the transit trajectory from low Earth orbit (LEO) to geosynchronous orbit (GEO) and beyond (free space). The Earth's geomagnetic field is located within the domain of LEO-GEO and, depending on latitude, extends out some 40,000-60,000 km. This field contains the Van Allen trapped electrons, protons, and low-energy plasmas, such as the nuclei of hydrogen, helium, oxygen, and to a lesser degree other atoms. In addition, there exist the geomagnetically attenuated energetic galactic cosmic rays (GCR). These particles are potentially harmful to improperly shielded crew members and onboard subsystems. Mitigation strategies to limit the exposure due to free space GCR and sporadic solar energetic particles (SEP) such as flare and coronal mass ejection (CME) must also be exercised beyond the trapped field. Presented in this work is the exposure analysis for a multi-vehicle mission planned for the epoch of February 2020 from LEO to the Earth-moon Lagrange-point two (L2), located approximately 63,000 km beyond the orbit of the Earth-moon binary system. Space operation at L2 provides a gravitationally stable orbit for a vehicle and partially eliminates the need for periodic thrust-vectoring to maintain orbital stability. In the cislunar (Earth-moon) space of L2, the mission trajectory and timeline in this work call for a cargo vehicle to rendezvous with a crew vehicle. This is followed by 15 days of space activities at L2 while the cargo and crew vehicles are docked after which the crew returns to Earth. The mission epoch of 2020 is specifically chosen as it is anticipated that the next solar minimum (i.e. end of cycle 24) in the Sun's approximate 11 years cycle will take place around this time. From a mission planning point of view, this date is ideal as the predictable GCR exposure will be at a maximum, while the sporadic SEP will be at a minimum. In addition, it is anticipated that by 2020 a vehicle capable of launching a crew of four will be operationally ready. During the LEO-GEO transit, the crew and cargo vehicles will encounter exposure from trapped particles and attenuated GCR, followed by free space exposure due to GCR and SEP during solar active times. Within the trapped field, a challenge arises from properly calculating the amount of exposure acquired. Within this field, in the absence of SEP (i.e. solar quiet times), the vehicles will have to transit through an inner proton belt, an inner and outer electron belts, and an attenuated GCR field. There exist a number of models to define the intensities of the trapped particles during the quiet and active SEP. Among the more established trapped models are the historic and popular electron/proton AE8/AP8 model dating back to the 1980s, the historic and less popular electron/proton CRRES model dating back to 1990s, and the recently released electron/proton/space plasma AE9/AP9/SPM model. The AE9/AP9/SPM model is a major improvement over the older AE8/AP8 and CRRES models. This model is derived from numerous measurements acquired over four solar cycles dating back to the 1970s, roughly representing 40 years of data collection. In contrast, the older AE8/AP8 and CRRES models were limited to only a few months of measurements taken during the prior solar minima and maxima. In this work, within the trapped field, along the design trajectory of the crew vehicle, the AE9/AP9/SPM model is evaluated against the older AE8/AP8 model during solar quiet times. The analysis is then extended to the GCR dominated en-route, cislunar L2 space and return trajectories in order to provide cumulative exposure estimates to the crew vehicle for the duration of the entire mission.

  4. Predictions for Radiation Shielding Materials

    NASA Technical Reports Server (NTRS)

    Kiefer, Richard L.

    2002-01-01

    Radiation from galactic cosmic rays (GCR) and solar particle events (SPE) is a serious hazard to humans and electronic instruments during space travel, particularly on prolonged missions outside the Earth s magnetic fields. Galactic cosmic radiation (GCR) is composed of approx. 98% nucleons and approx. 2% electrons and positrons. Although cosmic ray heavy ions are 1-2% of the fluence, these energetic heavy nuclei (HZE) contribute 50% of the long-term dose. These unusually high specific ionizations pose a significant health hazard acting as carcinogens and also causing microelectronics damage inside spacecraft and high-flying aircraft. These HZE ions are of concern for radiation protection and radiation shielding technology, because gross rearrangements and mutations and deletions in DNA are expected. Calculations have shown that HZE particles have a strong preference for interaction with light nuclei. The best shield for this radiation would be liquid hydrogen, which is totally impractical. For this reason, hydrogen-containing polymers make the most effective practical shields. Shielding is required during missions in Earth orbit and possibly for frequent flying at high altitude because of the broad GCR spectrum and during a passage into deep space and LunarMars habitation because of the protracted exposure encountered on a long space mission. An additional hazard comes from solar particle events (SPEs) which are mostly energetic protons that can produce heavy ion secondaries as well as neutrons in materials. These events occur at unpredictable times and can deliver a potentially lethal dose within several hours to an unshielded human. Radiation protection for humans requires safety in short-term missions and maintaining career exposure limits within acceptable levels on future long-term exploration missions. The selection of shield materials can alter the protection of humans by an order of magnitude. If improperly selected, shielding materials can actually increase radiation damage due to penetration properties and nuclear fragmentation. Protecting space-borne microelectronics from single event upsets (SEUs) by transmitted radiation will benefit system reliability and system design cost by using optimal shield materials. Long-term missions on the surface of the Moon or Mars will require the construction of habitats to protect humans during their stay. One approach to the construction is to make structural materials from lunar or Martian regolith using a polymeric material as a binder. The hydrogen-containing polymers are considerably more effective for radiation protection than the regolith, but the combination minimizes the amount of polymer to be transported. We have made composites of simulated lunar regolith with two different polymers, LaRC-SI, a high-performance polyimide thermoset, and polyethylene, a thermoplastic.

  5. Third generation cephalosporin resistant Enterobacteriaceae and multidrug resistant gram-negative bacteria causing bacteremia in febrile neutropenia adult cancer patients in Lebanon, broad spectrum antibiotics use as a major risk factor, and correlation with poor prognosis

    PubMed Central

    Moghnieh, Rima; Estaitieh, Nour; Mugharbil, Anas; Jisr, Tamima; Abdallah, Dania I.; Ziade, Fouad; Sinno, Loubna; Ibrahim, Ahmad

    2015-01-01

    Introduction: Bacteremia remains a major cause of life-threatening complications in patients receiving anticancer chemotherapy. The spectrum and susceptibility profiles of causative microorganisms differ with time and place. Data from Lebanon are scarce. We aim at evaluating the epidemiology of bacteremia in cancer patients in a university hospital in Lebanon, emphasizing antibiotic resistance and risk factors of multi-drug resistant organism (MDRO)-associated bacteremia. Materials and Methods: This is a retrospective study of 75 episodes of bacteremia occurring in febrile neutropenic patients admitted to the hematology-oncology unit at Makassed General Hospital, Lebanon, from October 2009-January 2012. It corresponds to epidemiological data on bacteremia episodes in febrile neutropenic cancer patients including antimicrobial resistance and identification of risk factors associated with third generation cephalosporin resistance (3GCR) and MDRO-associated bacteremia. Results: Out of 75 bacteremias, 42.7% were gram-positive (GP), and 57.3% were gram-negative (GN). GP bacteremias were mostly due to methicillin-resistant coagulase negative staphylococci (28% of total bacteremias and 66% of GP bacteremias). Among the GN bacteremias, Escherichia coli (22.7% of total, 39.5% of GN organisms) and Klebsiella pneumoniae(13.3% of total, 23.3% of GN organisms) were the most important causative agents. GN bacteremia due to 3GC sensitive (3GCS) bacteria represented 28% of total bacteremias, while 29% were due to 3GCR bacteria and 9% were due to carbapenem-resistant organisms. There was a significant correlation between bacteremia with MDRO and subsequent intubation, sepsis and mortality. Among potential risk factors, only broad spectrum antibiotic intake >4 days before bacteremia was found to be statistically significant for acquisition of 3GCR bacteria. Using carbapenems or piperacillin/tazobactam>4 days before bacteremia was significantly associated with the emergence of MDRO (p < 0.05). Conclusion: Our findings have major implications for the management of febrile neutropenia, especially in breakthrough bacteremia and fever when patients are already on broadspectrum antibiotics. Emergence of resistance to 3GCs and, to a lesser extent, to carbapenems in GN isolates has to be considered seriously in our local guidelines for empiric treatment of febrile neutropenia, especially given that their occurrence was proven to be associated with poorer outcomes. PMID:25729741

  6. The effect of irradiation on the magnetic properties of rock and synthetic samples with implications to irradiation of extraterrestrial materials in space

    NASA Astrophysics Data System (ADS)

    Bezaeva, N. S.; Gattacceca, J.; Rochette, P.; Duprat, J.; Rizza, G.; Vernazza, P.; Trukhin, V. I.

    2013-05-01

    Before reaching the Earth through meteorite falls or sample return, most extraterrestrial materials have been exposed to space radiations at different stages in their history. In the Solar System there are three main types of particle radiation: large fluxes of low-energy solar wind (SW) particles, smaller fluxes of high-energy galactic-cosmic-ray (GCR) particles, and intermittent intense fluxes of solar-flare-associated particles, also called solar cosmic rays or solar energetic particles (SEP). We report here the results of laboratory analog experiments to consider the potential effects of SEP and GCR on the magnetic properties of extraterrestrial materials. We carried out proton bombardment experiments (with irradiation energies E1=400 keV and E2=850 keV and three irradiation fluences in 1014-1016 p/cm2 range) and lead-ion bombardment experiments (E=1 GeV) on (previously demagnetized by 120 mT alternating magnetic field) rock and synthetic samples with the following magnetic carriers: metallic iron and nickel iron, Ti-rich and Ti-free magnetite, pyrrhotite. Irradiation experiments resulted in either further demagnetization or magnetization of irradiated samples depending on the type of magnetic mineralogy and type of ionizing radiation involved. Apart for the formation of radiation-induced remanent magnetization (RIRM), we observed major changes in bulk magnetic properties, i.e., a moderate to dramatic decrease (up to 93%) in the coercivity of remanence Bcr for all iron-bearing phases (iron-in-epoxy and Bensour meteorite samples). Contrary to iron-bearing samples, several magnetite-bearing samples experienced a radiation-induced magnetic hardening (increase in Bcr). Magnetic hardening was also observed for Ar2+ ion-irradiated nickel iron-bearing HED meteorites, measured for comparison with the previously stated results. Therefore, the combined effect of SEP with GCR may magnetically soften iron-bearing materials and harden magnetite-bearing materials. In order to answer the question weather RIRM may account for natural remanent magnetization of meteorites and lunar samples, physical mechanism of RIRM formation and potential dependence of RIRM intensity on the background magnetic field present during irradiation event should be investigated.

  7. Modelling human exposure to space radiation with different shielding: the FLUKA code coupled with anthropomorphic phantoms

    NASA Astrophysics Data System (ADS)

    Ballarini, F.; Alloni, D.; Battistoni, G.; Cerutti, F.; Ferrari, A.; Gadioli, E.; Garzelli, M. V.; Liotta, M.; Mairani, A.; Ottolenghi, A.; Paretzke, H. G.; Parini, V.; Pelliccioni, M.; Pinsky, L.; Sala, P.; Scannicchio, D.; Trovati, S.; Zankl, M.

    2006-05-01

    Astronauts' exposure to the various components of the space radiation field is of great concern for long-term missions, especially for those in deep space such as a possible travel to Mars. Simulations based on radiation transport/interaction codes coupled with anthropomorphic model phantoms can be of great help in view of risk evaluation and shielding optimisation, which is therefore a crucial issue. The FLUKA Monte Carlo code can be coupled with two types of anthropomorphic phantom (a mathematical model and a ''voxel'' model) to calculate organ-averaged absorbed dose, dose equivalent and ''biological'' dose under different shielding conditions. Herein the ''biological dose'' is represented by the average number of ''Complex Lesions'' (CLs) per cell in a given organ. CLs are clustered DNA breaks previously calculated by means of event-by-event track structure simulations at the nm level and integrated on-line into FLUKA, which adopts a condensed-history approach; such lesions have been shown to play a fundamental role in chromosome aberration induction, which in turn can be correlated with carcinogenesis. Examples of calculation results will be presented relative to Galactic Cosmic Rays, as well as to the August 1972 Solar Particle Event. The contributions from primary ions and secondary particles will be shown separately, thus allowing quantification of the role played by nuclear reactions occurring in the shield and in the human body itself. As expected, the SPE doses decrease dramatically with increasing the Al shielding thickness; nuclear reaction products, essentially due to target fragmentation, are of minor importance. A 10 g/cm2 Al shelter resulted to be sufficient to respect the 30-day limits for deterministic effects recommended for missions in Low Earth Orbit. In contrast with the results obtained for SPEs, the calculated GCR doses are almost independent of the Al shield thickness, and the GCR doses to internal organs are not significantly lower than the skin doses. Furthermore, nuclear interactions play a much larger role for GCR than for SPE doses.

  8. Long-term modulation of Galactic Cosmic Radiation and its model for space exploration.

    PubMed

    Badhwar, G D; O'Neill, P M

    1994-10-01

    As the human exploration of space has received new attention in the United States, studies find that exposure to space radiation could adversely impact the mission design. Galactic Cosmic Radiation (GCR), with its very wide range of charges and energies, is particularly important for a mission to Mars, because it imposes a stiff mass penalty for spacecraft shielding. Dose equivalent versus shielding thickness calculations, show a rapid initial drop in exposure with thickness, but an asymptotic behavior at a higher shielding thickness. Uncertainties in the radiobiology are largely unknown. For a fixed radiation risk, this leads to large uncertain ties in shielding thickness for small uncertainties in estimated dose. In this paper we investigate the application of steady-state, spherically-symmetric diffusion-convection theory of solar modulation to individual measurements of differential energy spectra from 1954 to 1989 in order to estimate the diffusion coefficient, kappa (r,t), as a function of time. We have correlated the diffusion coefficient to the Climax neutron monitor rates and show that, if the diffusion coefficient can be separated into independent functions of space and time: kappa (-r,t)=K(t)kappa 0 beta P kappa 1(r), where beta is the particle velocity and P the rigidity, then (i) The time dependent quantity 1/K(t), which is proportional to the deceleration potential, phi(r,t), is linearly related to the Climax neutron monitor counting rate. (ii) The coefficients obtained from hydrogen or helium intensity measurements are the same. (iii) There are different correlation functions for odd and even solar cycles. (iv) The correlation function for the Climax neutron monitor counting rate for given time, t, can be used to estimate mean deceleration parameter phi(t) to within +/- 15% with 90% confidence. We have shown that kappa(r,t) determined from hydrogen and/or helium data, can be used to fit the oxygen and iron differential energy spectra with a root mean square error of about +/- 10%, and essentially independent of the particle charge or energy. We have also examined the ion chamber and 14C measurements which allow the analysis to be extended from the year 1906 to 1990. Using this model we have defined reference GCR spectra at solar minimum and solar maximum. These can be used for space exploration studies and provide a quantitative estimate of the error in dose due to changes in GCR intensities. PMID:11540020

  9. NAIRAS aircraft radiation model development, dose climatology, and initial validation

    PubMed Central

    Mertens, Christopher J; Meier, Matthias M; Brown, Steven; Norman, Ryan B; Xu, Xiaojing

    2013-01-01

    [1] The Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) is a real-time, global, physics-based model used to assess radiation exposure to commercial aircrews and passengers. The model is a free-running physics-based model in the sense that there are no adjustment factors applied to nudge the model into agreement with measurements. The model predicts dosimetric quantities in the atmosphere from both galactic cosmic rays (GCR) and solar energetic particles, including the response of the geomagnetic field to interplanetary dynamical processes and its subsequent influence on atmospheric dose. The focus of this paper is on atmospheric GCR exposure during geomagnetically quiet conditions, with three main objectives. First, provide detailed descriptions of the NAIRAS GCR transport and dosimetry methodologies. Second, present a climatology of effective dose and ambient dose equivalent rates at typical commercial airline altitudes representative of solar cycle maximum and solar cycle minimum conditions and spanning the full range of geomagnetic cutoff rigidities. Third, conduct an initial validation of the NAIRAS model by comparing predictions of ambient dose equivalent rates with tabulated reference measurement data and recent aircraft radiation measurements taken in 2008 during the minimum between solar cycle 23 and solar cycle 24. By applying the criterion of the International Commission on Radiation Units and Measurements (ICRU) on acceptable levels of aircraft radiation dose uncertainty for ambient dose equivalent greater than or equal to an annual dose of 1 mSv, the NAIRAS model is within 25% of the measured data, which fall within the ICRU acceptable uncertainty limit of 30%. The NAIRAS model predictions of ambient dose equivalent rate are generally within 50% of the measured data for any single-point comparison. The largest differences occur at low latitudes and high cutoffs, where the radiation dose level is low. Nevertheless, analysis suggests that these single-point differences will be within 30% when a new deterministic pion-initiated electromagnetic cascade code is integrated into NAIRAS, an effort which is currently underway.

  10. Impact of Track Structure Effects on Shielding and Dosimetry

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Cucinotta, F. A.; Schimmerling, W.; Kim, M. Y.

    1999-01-01

    Galactic cosmic rays (GCR) consisting of nuclei of all the known elements with kinetic energies extending from tens to millions of MeV pose a significant health hazard to future deep space operations. Even half of the radiation exposures expected in ISS will result from GCR components. The biological actions of these radiations are known to depend on the details of the energy deposition (not just linear energy transfer, LET, but the lateral dispersion of energy deposition about the particle track). Energy deposits in tissues are dominated by the transfer of tens to hundreds of eV to the tissue's atomic electrons. In the case of low LET radiations, the collisions are separated by large dimensions compared to the size of important biomolecular structures. If such events are also separated in time, then the radiation adds little to the background of radicals occurring from ordinary metabolic processes and causes little or no biological injury. Hence, dose rate is a strong determinant of the action of low LET exposures. The GCR exposures are dominated by ions of high charge and energy (HZE) characterized by many collisions with atomic electrons over biomolecular dimensions, resulting in high radical- density events associated with a few isolated ion paths through the cell and minimal dose rate dependence at ordinary exposure levels. The HZE energy deposit declines quickly laterally and merges with the background radical density in the track periphery for which the exact lateral distribution of the energy deposit is the determinant of the biological injury. Although little data exists on human exposures from HZE radiations, limited studies in mice and mammalian cell cultures allow evaluation of the effects of track structure on shield attenuation properties and evaluation of implications for dosimetry. The most complete mammalian cell HZE exposure data sets have been modeled including the C3H10T1/2 survival and transformation data of Yang et al., the V79 survival and mutation data of various groups, and the Harderian gland tumor data of Alpen et al. Model results for the Harderian gland tumor data in comparison with data from Alpen et al. The Harderian target cell initiation cross section compares closely with the transformation cross section found for the C3H10T1/2 cell transformation data of Yang et al. The most notable feature of the cross sections are the multivalued cross sections for a given LET which implies the corresponding relative biological effectiveness (RBE) is dependent not only on the LET but also the ion type. This fact is at variance with the latest ICRP recommended quality factor which is a defined function of only the LET.

  11. Secondary particle contribution to LET spectra on LDEF.

    PubMed

    Benton, E R; Benton, E V; Frank, A L; Frigo, L A; Csige, I

    1996-11-01

    Four experiments utilizing passive detectors (P0006, P0004, A0015, M0004) were flown on LDEF to study the radiation environment. These experiments have been summarized in a companion paper (Benton et al., 1996). One of the experimental goals was to measure LET spectra at different locations and shielding depths with plastic nuclear track detectors (PNTD). It was found that the LET spectra extended well above the LET cutoff imposed by the geomagnetic field on GCR particle penetration into LEO. The high LET particles detected were mostly short-range (range < 2000 m), indicating that they were secondaries produced locally within the PNTD. The presence of these high LET particle fluences is important for the determination of dose equivalent because of the high Quality Factors (Q) involved. A relatively small fraction of particle fluence can contribute a large fraction of dose equivalent. Short-range, inelastic secondary particles produced by trapped protons in the South Atlantic Anomaly (SAA) were found to be a major contributor to the LET spectra above 100 keV/micrometer. The LET spectra were found to extend beyond the approximately 137 keV/micrometer relativistic GCR Fe peak to over 1000 keV/micrometer. The high LET tail of the LET spectra was measured in CR-39 and polycarbonate PNTDs using different techniques. GCR made a relatively modest contribution to the LET spectra as compared to the contributions from short-range secondary particles and stopping protons. LET spectra intercomparisons were made between LDEF measurements and exposures to 154 MeV accelerated proton beams. The similarities support the role of nuclear interactions by trapped protons as the major source of secondary particles in the PNTDs. Also techniques were employed to reduce the range cutoff for detection of the short-range secondaries to approximately 1 micrometer, so that essentially all secondary particles were included in the LET spectra. This has allowed a more realistic assessment of secondary contribution to dose equivalent. Comparisons of measured and calculated LET spectra have been made that demonstrate the need for more accurate modeling of secondary particles in radiation transport codes. Comparisons include preliminary calculations in which attempts have been made to include secondary particles. PMID:11540511

  12. Global Corruption Report 2001

    NSDL National Science Digital Library

    2001-01-01

    Released on October 15, this new annual report from Transparency International (TI, see the September 7, 2000 Scout Report for Business & Economics) reviews the "state of corruption" worldwide, July 2000-June 2001. After the introduction and prefatory material, the report is divided into three main sections: Regional reports, Global issues (such as money laundering and an update from OECD on implementing the Anti-Bribery Convention), and Data and research, which summarizes a wide variety of research projects from governments, private organizations, scholars, international organizations, and more. The About the GCR link on the front page of the report gives a summary of authors contributing to the different report sections and an overview of the report as a whole. The report is designed for a wide audience and should appeal both to policymakers and interested members of the general public.

  13. Radiation protection using Martian surface materials in human exploration of Mars

    NASA Technical Reports Server (NTRS)

    Kim, M. H.; Thibeault, S. A.; Wilson, J. W.; Heilbronn, L.; Kiefer, R. L.; Weakley, J. A.; Dueber, J. L.; Fogarty, T.; Wilkins, R.

    2001-01-01

    To develop materials for shielding astronauts from the hazards of GCR, natural Martian surface materials are considered for their potential as radiation shielding for manned Mars missions. The modified radiation fluences behind various kinds of Martian rocks and regolith are determined by solving the Boltzmann equation using NASA Langley's HZETRN code along with the 1977 Solar Minimum galactic cosmic ray environmental model. To develop structural shielding composite materials for Martian surface habitats, theoretical predictions of the shielding properties of Martian regolith/polyimide composites has been computed to assess their shielding effectiveness. Adding high-performance polymer binders to Martian regolith to enhance structural properties also enhances the shielding properties of these composites because of the added hydrogenous constituents. Heavy ion beam testing of regolith simulant/polyimide composites is planned to validate this prediction. Characterization and proton beam tests are performed to measure structural properties and to compare the shielding effects on microelectronic devices, respectively.

  14. Solar particle events observed at Mars: dosimetry measurements and model calculations.

    PubMed

    Cleghorn, Timothy F; Saganti, Premkumar B; Zeitlin, Cary J; Cucinotta, Francis A

    2004-01-01

    During the period from March 13, 2002 to mid-September, 2002, six solar particle events (SPE) were observed by the MARIE instrument onboard the Odyssey Spacecraft in Martian Orbit. These events were observed also by the GOES 8 satellite in Earth orbit, and thus represent the first time that the same SPE have been observed at these separate locations. The characteristics of these SPE are examined, given that the active regions of the solar disc from which the event originated can usually be identified. The dose rates at Martian orbit are calculated, both for the galactic and solar components of the ionizing particle radiation environment. The dose rates due to galactic cosmic rays (GCR) agree well with the HZETRN model calculations. PMID:15791734

  15. Radiation shield requirements for manned nuclear propulsion space vehicles

    NASA Astrophysics Data System (ADS)

    Sager, Paul H.

    1992-01-01

    Manned nuclear propulsion space vehicles require radiation shielding to protect the crew from a number of diverse radiation sources: the propulsion system reactor, the Earth's Van Allen radiation belts, anomalously large solar proton events (ALSPEs), and galactic cosmic radiation (GCR). The sources are characterized not only in terms of species and energy spectrum, but also by frequency, duration, and probability of occurrence. Such factors as effectiveness of available vehicle materials (such as propellants) in providing shielding and operational strategies (such as multiple periapsis burns) must be factored into the design and mission planning for the vehicle. The optimum distribution of the shielding to limit exposure to the crew and meet established dose limits with minimum vehicle mass was determined for a typical Mars transfer vehicle using a NERVA-derivative nuclear rocket engine. For this case, the optimum shielding for a 434-day mission was also adequate to limit the exposure of crew to short-term exposure to historical ALSPEs.

  16. Once we know all the radiobiology we need to know, how can we use it to predict space radiation risks and achieve fame and fortune?

    NASA Technical Reports Server (NTRS)

    Cucinotta, F. A.

    2001-01-01

    It has been over 40 years since occupational radiation exposures to NASA's astronauts began and more than 300 individuals have been exposed to low and intermediate doses of trapped protons and galactic cosmic rays (GCR). The International Space Station (ISS) will add substantially to this number and significantly increase average lifetime doses. We review these exposures in this report. After many years of investigation, the method used to assess risk have not changed significantly. However, molecular biology and genetics have made enormous progress in establishing the mechanisms of cancer formation, damage to the central nervous system, and individual variation in sensitivity to radiation. We discuss critical questions and possible new approaches to the prediction of risk from space radiation exposures. Experimental models can lead to testable theories that along with extensive biophysical and informatics approaches, will lead to fame and fortune by allowing for accurate projections of astronaut risks and for the development of biological countermeasures.

  17. Prototype Biology-Based Radiation Risk Module Project

    NASA Technical Reports Server (NTRS)

    Terrier, Douglas; Clayton, Ronald G.; Patel, Zarana; Hu, Shaowen; Huff, Janice

    2015-01-01

    Biological effects of space radiation and risk mitigation are strategic knowledge gaps for the Evolvable Mars Campaign. The current epidemiology-based NASA Space Cancer Risk (NSCR) model contains large uncertainties (HAT #6.5a) due to lack of information on the radiobiology of galactic cosmic rays (GCR) and lack of human data. The use of experimental models that most accurately replicate the response of human tissues is critical for precision in risk projections. Our proposed study will compare DNA damage, histological, and cell kinetic parameters after irradiation in normal 2D human cells versus 3D tissue models, and it will use a multi-scale computational model (CHASTE) to investigate various biological processes that may contribute to carcinogenesis, including radiation-induced cellular signaling pathways. This cross-disciplinary work, with biological validation of an evolvable mathematical computational model, will help reduce uncertainties within NSCR and aid risk mitigation for radiation-induced carcinogenesis.

  18. Solar particle events observed at Mars: dosimetry measurements and model calculations

    NASA Technical Reports Server (NTRS)

    Cleghorn, Timothy F.; Saganti, Premkumar B.; Zeitlin, Cary J.; Cucinotta, Francis A.

    2004-01-01

    During the period from March 13, 2002 to mid-September, 2002, six solar particle events (SPE) were observed by the MARIE instrument onboard the Odyssey Spacecraft in Martian Orbit. These events were observed also by the GOES 8 satellite in Earth orbit, and thus represent the first time that the same SPE have been observed at these separate locations. The characteristics of these SPE are examined, given that the active regions of the solar disc from which the event originated can usually be identified. The dose rates at Martian orbit are calculated, both for the galactic and solar components of the ionizing particle radiation environment. The dose rates due to galactic cosmic rays (GCR) agree well with the HZETRN model calculations. Published by Elsevier Ltd on behalf of COSPAR.

  19. Mars Surface Ionizing Radiation Environment: Need for Validation

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Kim, M. Y.; Clowdsley, M. S.; Heinbockel, J. H.; Tripathi, R. K.; Singleterry, R. C.; Shinn, J. L.; Suggs, R.

    1999-01-01

    Protection against the hazards from exposure to ionizing radiation remains an unresolved issue in the Human Exploration and Development of Space (HEDS) enterprise [1]. The major uncertainty is the lack of data on biological response to galactic cosmic ray (GCR) exposures but even a full understanding of the physical interaction of GCR with shielding and body tissues is not yet available and has a potentially large impact on mission costs. "The general opinion is that the initial flights should be short-stay missions performed as fast as possible (so-called 'Sprint' missions) to minimize crew exposure to the zero-g and space radiation environment, to ease requirements on system reliability, and to enhance the probability of mission success." The short-stay missions tend to have long transit times and may not be the best option due to the relatively long exposure to zero-g and ionizing radiation. On the other hand the short-transit missions tend to have long stays on the surface requiring an adequate knowledge of the surface radiation environment to estimate risks and to design shield configurations. Our knowledge of the surface environment is theoretically based and suffers from an incomplete understanding of the physical interactions of GCR with the Martian atmosphere, Martian surface, and intervening shield materials. An important component of Mars surface robotic exploration is the opportunity to test our understanding of the Mars surface environment. The Mars surface environment is generated by the interaction of Galactic Cosmic Rays (GCR) and Solar Particle Events (SPEs) with the Mars atmosphere and Mars surface materials. In these interactions, multiple charged ions are reduced in size and secondary particles are generated, including neutrons. Upon impact with the Martian surface, the character of the interactions changes as a result of the differing nuclear constituents of the surface materials. Among the surface environment are many neutrons diffusing from the Martian surface and especially prominent are energetic neutrons with energies up to a few hundred MeV. Testing of these computational results is first supported by ongoing experiments at the Brookhaven National Laboratory but equally important is the validation to the extent possible by measurements on the Martian surface. Such measurements are limited by power and weight requirements of the specific mission and simplified instrumentation by necessity lacks the full discernment of particle type and spectra as is possible with laboratory experimental equipment. Yet, the surface measurements are precise and a necessary requisite to validate our understanding of the surface environment. At the very minimum the surface measurements need to provide some spectral information on the neutron environment. Of absolute necessity is the precise knowledge of the detector response functions for absolute comparisons between the computational model of the surface environment and the detector measurements on the surface.

  20. Radiation Protection for Manned Interplanetary Missions - Radiation Sources, Risks, Remedies

    NASA Astrophysics Data System (ADS)

    Facius, R.; Reitz, G.

    Health risks in interplanetary explorative missions differ in two major features significantly from those during the manned missions experienced so far. For one, presently available technologies lead to durations of such missions significantly longer than so far encountered - with the added complication that emergency returns are ruled out. Thus radiation exposures and hence risks for late radiation sequelae like cancer increase proportional to mission duration - similar like most other health and many technical risks too. Secondly, loss of the geomagnetic shielding available in low earth orbits (LEO) does increase the radiation dose rates from galactic cosmic rays (GCR) since significant fractions of the GCR flux below about 10 GeV/n now can reach the space vehicle. In addition, radiation from solar particle events (SPE) which at most in polar orbit segments can contribute to the radiation exposure during LEO missions now can reach the spaceship unattenuated. Radiation doses from extreme SPEs can reach levels where even early acute radiation sickness might ensue - with the added risks from potentially associated crew performance decrements. In contrast to the by and large predictable GCR contribution, the doses and hence risks from large SPEs can only stochastically be assessed. Mission designers face the task to contain the overall health risk within acceptable limits. Towards this end they have to transport the particle fluxes of the radiation fields in free space through the walls of the spaceship and through the tissue of the astronaut to the radiation sensitive organs. To obtain a quantity which is useful for risk assessment, the radiobiological effectiveness as well as the specific sensitivity of a given organ has to be accounted for in such transport calculations which of course require a detailed knowledge of the spatial distribution and the atomic composition of the surrounding shielding material. In doing so the mission designer encounters two major difficulties in addition to those connected with the knowledge of the external radiation fields and the cross sections necessary for the transport calculations. The radiobiological effectiveness of the GCR heavy ions is to a large extent only nominally known with large error margins. Furthermore, the reference risk, late cancer mortality, usually only materializes many years after the mission, in contrast to the risk from early radiation sickness or the other health risks, including those from prolonged exposure to weightlessness. 1 Given these large radiobiological uncertainties of space radiation risk assessment, a first and most effective countermeasure consists of research directed at their diminishment. Furthermore, a new risk criterion is needed which allows a unified quantitative treatment of all health and technical risks arising during the mission as well as the risk of late radiogenic cancer mortality many years after the mission. Countermeasures to reduce radiation exposure comprise judicious planning of the mission with respect to solar activity, skilful utilization and optimization of shielding materials, and research into advanced propulsion systems capable to cut down transit times in free space. Finally, research into means to reduce sensitivity to radiation health effects e.g. by chemical substances and nutritional additives constitutes the third class of possible countermeasures. Arguably, the single most effective among these measures would be reduction of transit time in free space. 2

  1. End-To-End Risk Assesment: From Genes and Protein to Acceptable Radiation Risks for Mars Exploration

    NASA Astrophysics Data System (ADS)

    Cucinotta, Francis A.; Schimmerling, Walter

    2000-07-01

    The human exploration of Mars will impose unavoidable health risks from galactic cosmic rays (GCR) and possibly solar particle events (SPE). It is the goal of NASA's Space Radiation Health Program to develop the capability to predict health risks with significant accuracy to ensure that risks are well below acceptable levels and to allow for mitigation approaches to be effective at reasonable costs. End-to-End risk assessment is the approach being followed to understand proton and heavy ion damage at the molecular, cellular, and tissue levels in order to predict the probability of the major health risk including cancer, neurological disorders, hereditary effects, cataracts, and acute radiation sickness and to develop countermeasures for mitigating risks.

  2. LRO Cosmic Ray Telescope for the Effects of Radiation (CRaTER): Instrument Overviw and Computer Simulations of Detector Response to SEPs and GCRs

    NASA Astrophysics Data System (ADS)

    Charara, Y.; Towsend, L.; Spence, H.; Blake, J. B.; Golightly, M.; Kepko, E.; Kasper, J.; Looper, M.; Mazur, J.

    2006-12-01

    The Lunar Reconnaissance Orbiter (LRO) Mission, scheduled to be launched by the end of 2008, will carry six instruments to serve several exploratory objectives for a return of astronauts to the Moon. One of the six instruments, the Cosmic Ray Telescope for the Effects of Radiation (CRaTER), will characterize the lunar radiation environment and its biological impacts on humans. In this presentation, we provide an overview of CRaTER measurement objectives and implementation. CRaTER has two Tissue Equivalent Plastic volumes embedded between three pairs of solid-state detectors. We present preliminary computer calculations of expected CRaTER detector responses to Solar Energetic Particles (SEPs) and Galactic Cosmic Rays (GCRs) by simulating several SEPs and energetic, heavy, GCR particle spectra using two state-of-the-art Monte Carlo Codes, HETC-HEDS and BBFRAG.

  3. Low concentration ratio solar array for low Earth orbit multi-100kW application. Volume 2: Drawings

    NASA Technical Reports Server (NTRS)

    Nalbandian, S. J.; French, E. P.

    1982-01-01

    A preliminary design effort directed toward a low concentration ratio photovoltaic array system based on 1984 technology and capable of delivering multi-hundred kilowatts (300 kW to 100 kW range) in low Earth orbit. The array system consists of two or more array modules each capable of delivering between 113 kW to 175 kW using silicon solar cells or gallium arsenide solar cells, respectively. The array module deployed area is 1320 square meters and consists of 4356 pyramidal concentrator elements. The module, when stowed in the Space Shuttle's payload bay, has a stowage volume of a cube with 3.24 meters on a side. The concentrator elements are sized for a geometric concentration ratio (GCR) of six with an aperture area of 0.5 meters x 0.5 meters. Drawings for the preliminary design configuration and for the test hardware that was fabricated for design evaluation and test are provided.

  4. Application of blind source separation to gamma ray spectra acquired by GRaND around Vesta

    NASA Astrophysics Data System (ADS)

    Mizzon, H.; Toplis, M. J.; Forni, O.; Prettyman, T. H.; Raymond, C. A.; Russell, C. T.

    2012-12-01

    The bismuth germinate (BGO) scintillator is one of the sensors of the gamma ray and neutron detector (GRaND)1 on board the Dawn spacecraft, that has spent just over one year in orbit around the asteroid 4-Vesta. The BGO detector is excited by energetic gamma-rays produced by galactic cosmic rays (GCR) or energetic solar particles interacting either with Vesta and/or the Dawn spacecraft. In detail, during periods of quiet solar activity, gamma ray spectra produced by the scintillator can be considered as consisting of three signals: i) a contribution of gamma-rays from Vesta produced by GCR interactions at the asteroid's surface, ii) a contribution from the spacecraft excited by neutrons coming from Vesta, and iii) a contribution of the spacecraft excited by local interaction with galactic cosmic rays. While the first two contributions should be positive functions of the solid angle of Vesta in the field of view during acquisition, the last one should have a negative dependence because Vesta partly shields the spacecraft from GCR. This theoretical mix can be written formally as: S=a?SV+b?SSCNV+c(4?-?)SSCGCR (1) where S is the series of recorded spectra, ? is the solid angle, SV is the contribution of gamma rays coming from Vesta, SSCNV is the contribution of gamma rays coming from the spacecraft excited by the neutron coming from Vesta and SSCGCR is the contribution of gamma rays coming from the spacecraft excited by GCR. A blind source separation method called independent component analysis enables separating additive subcomponents supposing the mutual statistical independence of the non-Gaussian source signals2. Applying this method to BGO spectra acquired during the first three months of the low-altitude measurement orbit (LAMO) reveals two main independent components. The first one is dominated by the positron electron annihilation peak and is positively correlated to the solid angle. The second is negatively correlated to the solid angle and displays peaks of elements present in the spacecraft, of energy in the range 1 to 3.5 MeV. At energy >3.5 MeV, the dominant independent component highlighted by this method has no significant peaks, suggesting that it is not influenced by Vesta itself which is known to have a strong signal associated with iron at 7.6 MeV. Our method therefore represents a first step in retrieving the contribution of the spacecraft that could be used in conjunction with the mixing equation (1) to determine the contribution from the planet itself. 1 : Prettyman, T. H., Mcsween, Jr., H. Y., Feldman, W. C., JUN 2010. Dawn's GRaND to map the chemical composition of asteroids Vesta and Ceres. Geochimica and Cosmochimica Acta 74 (12, 1), A832, Con- ference on Goldschmidt 2010 - Earth, Energy, and the Environment, Knoxville, TN, JUN 13-18, 2010. 2 : Hyvarinen, A., Oja, E., May-Jun 2000. Independent component analysis: algorithms and applications. Neural Networks 13 (4-5), 411-430.

  5. Hydrogen Absorbing Materials for Use as Radiation Shielding During Extended Space Flight Missions

    NASA Technical Reports Server (NTRS)

    Grugel, Richard N.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Minimizing radiation exposure from the galactic cosmic ray (GCR) environment during extended space missions is particularly crucial to crew health and safety. Here, an ideal candidate for shielding would be pure solid or liquid hydrogen, a material that effectively fragments heavy ions into ones of lower mass and energy that are more easily attenuated. Unfortunately, utilizing pure hydrogen is not presently feasible. It is, however, known that the hydrogen content of other materials (for example, metal hydrides, palladium alloys, and organic compounds) can exceed that of pure solid hydrogen and thus merit consideration as shielding candidates. This presentation will discuss an ongoing effort to develop novel shielding from such materials in concert with a coordinated testing/evaluation and modeling effort.

  6. Radiation issues for piloted Mars mission

    NASA Technical Reports Server (NTRS)

    Badhwar, Gautam D.; Nachtwey, D. S.; Yang, Tracy C.

    1992-01-01

    Current radiation risk for a piloted Mars mission is estimated using the idea of absorbed dose and ICRP-26, LET-dependent quality factors. In a spacecraft with aluminum walls (2 g/sq cm) at solar minimum the calculated dose equivalent is 0.73 Sv for a 406-day mission. Based on the current thinking this leads to an excess cancer mortality in a 35-year male of about 1 percent. About 75 percent of the dose equivalent is contributed by HZE particles and target fragments with average quality factors of 10.3 and 20, respectively. The entire concept of absorbed dose, quality factor, and dose equivalent as applied to such missions needs to be reexamined, in light of the fact that less than 50 percent of the nuclei in the body of the astronaut would have been traversed by a single GCR nuclei in the 406-day mission.

  7. Spatial Analysis of Galactic Cosmic Ray Particles in Low Earth Orbit/Near Equator Orbit Using SPENVIS

    NASA Astrophysics Data System (ADS)

    Suparta, W.; Zulkeple, S. K.

    2014-04-01

    The space environment has grown intensively harmful to spacecraft and astronauts. Galactic cosmic rays (GCRs) are one of the radiation sources that composed of high energetic particles originated from space and capable of damaging electronic systems through single event upset (SEU) process. In this paper, we analyzed GCR fluxes at different altitudes by using Space Environment Information System (SPENVIS) software and the results are compared to determine their intensities with respect to distance in the Earth's orbit. The altitudes are set at low earth orbit (400 km and 685 km), medium earth orbit (19,100 km and 20,200 km) and high earth orbit (35,793 km and 1,000,000 km). Then, within Low Earth Orbit (LEO) near the equator (NEqO), we used altitude of 685 km to compare GCRs with the intensities of solar particles and trapped particles in the radiation belt to determine the significance of GCRs in the orbit itself.

  8. End-To-End Risk Assesment: From Genes and Protein to Acceptable Radiation Risks for Mars Exploration

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Schimmerling, Walter

    2000-01-01

    The human exploration of Mars will impose unavoidable health risks from galactic cosmic rays (GCR) and possibly solar particle events (SPE). It is the goal of NASA's Space Radiation Health Program to develop the capability to predict health risks with significant accuracy to ensure that risks are well below acceptable levels and to allow for mitigation approaches to be effective at reasonable costs. End-to-End risk assessment is the approach being followed to understand proton and heavy ion damage at the molecular, cellular, and tissue levels in order to predict the probability of the major health risk including cancer, neurological disorders, hereditary effects, cataracts, and acute radiation sickness and to develop countermeasures for mitigating risks.

  9. Particle directionality and trapped proton fluences on LDEF.

    PubMed

    Nefedov, N; Csige, I; Benton, E V; Frank, A L; Frigo, L A; Benton, E R

    1996-11-01

    Directionality of incident space radiation is a significant factor in spacecraft shielding and astronaut dosimetry in low Earth orbit (LEO). Particle directionality of GCR and trapped protons were measured on LDEF with plastic nuclear track detectors (PNTD) from the P0006 west-side experiment. This experiment consisted of a thick detector stack and is described more fully in a companion article (Benton et al., 1996). The anisotropy of the trapped protons produced maximum intensity for protons arriving from the west. The fluences of the eastward directed trapped protons have been measured by selection of the particles on the basis of range in the PNTDs. The measured fluences are compared with the model calculations of Armstrong and Colborn (1993). PMID:11540520

  10. Radiation Protection for Lunar Mission Scenarios

    NASA Technical Reports Server (NTRS)

    Clowdsley, Martha S.; Nealy, John E.; Wilson, John W.; Anderson, Brooke M.; Anderson, Mark S.; Krizan, Shawn A.

    2005-01-01

    Preliminary analyses of shielding requirements to protect astronauts from the harmful effects of radiation on both short-term and long-term lunar missions have been performed. Shielding needs for both solar particle events (SPEs) and galactic cosmic ray (GCR) exposure are discussed for transit vehicles and surface habitats. This work was performed under the aegis of two NASA initiatives. The first study was an architecture trade study led by Langley Research Center (LaRC) in which a broad range of vehicle types and mission scenarios were compared. The radiation analysis for this study primarily focused on the additional shielding mass required to protect astronauts from the rare occurrence of a large SPE. The second study, led by Johnson Space Center (JSC), involved the design of lunar habitats. Researchers at LaRC were asked to evaluate the changes to mission architecture that would be needed if the surface stay were lengthened from a shorter mission duration of 30 to 90 days to a longer stay of 500 days. Here, the primary radiation concern was GCR exposure. The methods used for these studies as well as the resulting shielding recommendations are discussed. Recommendations are also made for more detailed analyses to minimize shielding mass, once preliminary vehicle and habitat designs have been completed. Here, methodologies are mapped out and available radiation analysis tools are described. Since, as yet, no dosimetric limits have been adopted for missions beyond low earth orbit (LEO), radiation exposures are compared to LEO limits. Uncertainties associated with the LEO career effective dose limits and the effects of lowering these limits on shielding mass are also discussed.

  11. Fundamentals of Aerospace Medicine: Cosmic Radiation

    NASA Technical Reports Server (NTRS)

    Bagshaw, Michael; Cucionotta, Francis A.

    2007-01-01

    Cosmic rays were discovered in 1911 by the Austrian physicist, Victor Hess. The planet earth is continuously bathed in high-energy galactic cosmic ionizing radiation (GCR), emanating from outside the solar system, and sporadically exposed to bursts of energetic particles from the sun referred to as solar particle events (SPEs). The main source of GCR is believed to be supernovae (exploding stars), while occasionally a disturbance in the sun's atmosphere (solar flare or coronal mass ejection) leads to a surge of radiation particles with sufficient energy to penetrate the earth's magnetic field and enter the atmosphere. The inhabitants of planet earth gain protection from the effects of cosmic radiation from the earth s magnetic field and the atmosphere, as well as from the sun's magnetic field and solar wind. These protective effects extend to the occupants of aircraft flying within the earth s atmosphere, although the effects can be complex for aircraft flying at high altitudes and high latitudes. Travellers in space do not have the benefit of this protection and are exposed to an ionizing radiation field very different in magnitude and quality from the exposure of individuals flying in commercial airliners. The higher amounts and distinct types of radiation qualities in space lead to a large need for understanding the biological effects of space radiation. It is recognized that although there are many overlaps between the aviation and the space environments, there are large differences in radiation dosimetry, risks and protection for airline crew members, passengers and astronauts. These differences impact the application of radiation protection principles of risk justification, limitation, and the principle of as low as reasonably achievable (ALARA). This chapter accordingly is divided into three major sections, the first dealing with the basic physics and health risks, the second with the commercial airline experience, and the third with the aspects of cosmic radiation appertaining to space travel including future considerations.

  12. DHS Written Report

    SciTech Connect

    Palomares, Javier [Los Alamos National Laboratory

    2012-08-31

    Recently, a new galactic cosmic-ray (GCR) source option [1] was implemented in the all-energy, all-particle transport code MCNP6 [2]. In this paper, we made use of this feature to calculate surface neutron and photon background fluxes on a terrestrial grid around the earth. These spectra have been incorporated into Release 2 of the 'background.dat' file, which is read and sampled by MCNP6 whenever a user invokes the background source option [2]. Cosmic radiation bombards Earth with various particles, such as protons and {alpha} particles, some of which are deflected by the Earth's shielding magnetic field. Particles that carry sufficient energy can overcome the deflection and penetrate into the atmosphere. The sufficient energy is dependent on the terrestrial coordinates due to the magnetic force's proportionality to the sine of the angle between the velocity vector of the incoming particle and the magnetic field. As the particles propagate through the atmosphere, collisions with atmospheric molecules generate new particles such as neutrons, protons, photons, muons, pions, and other exotic particles. These secondary often have sufficient energy to undergo additional nuclear interactions, and so on, forming what is known as a cascade shower. The tabulation of background particle fluxes on the surface of the earth is important for a variety of reasons, one of which is the design of nuclear material detection systems. The simulations used various models and formulations for the cosmic source spectra, atmosphere, and terrestrial conditions to correctly model the propagation of GCR particles through the atmosphere to surface level.

  13. Comparison of organ dose and dose equivalent for human phantoms of CAM vs. MAX

    NASA Astrophysics Data System (ADS)

    Kim, Myung-Hee Y.; Qualls, Garry D.; Slaba, Tony C.; Cucinotta, Francis A.

    2010-04-01

    For the evaluation of organ dose and dose equivalent of astronauts on space shuttle and the International Space Station (ISS) missions, the CAMERA models of CAM (Computerized Anatomical Male) and CAF (Computerized Anatomical Female) of human tissue shielding have been implemented and used in radiation transport model calculations at NASA. One of new human geometry models to meet the “reference person” of International Commission on Radiological Protection (ICRP) is based on detailed Voxel (volumetric and pixel) phantom models denoted for male and female as MAX (Male Adult voXel) and FAX (Female Adult voXel), respectively. We compared the CAM model predictions of organ doses to those of MAX model, since the MAX model represents the male adult body with much higher fidelity than the CAM model currently used at NASA. Directional body-shielding mass was evaluated for over 1500 target points of MAX for specified organs considered to be sensitive to the induction of stochastic effects. Radiation exposures to solar particle event (SPE), trapped protons, and galactic cosmic ray (GCR) were assessed at the specific sites in the MAX phantom by coupling space radiation transport models with the relevant body-shielding mass. The development of multiple-point body-shielding distributions at each organ made it possible to estimate the mean and variance of organ doses at the specific organ. For the estimate of doses to the blood forming organs (BFOs), data on active marrow distributions in adult were used to weight the bone marrow sites over the human body. The discrete number of target points of MAX organs resulted in a reduced organ dose and dose equivalent compared to the results of CAM organs especially for SPE, and should be further investigated. Differences of effective doses between the two approaches were found to be small (<5%) for GCR.

  14. Characterization of the particle radiation environment at three potential landing sites on Mars using ESA’s MEREM models

    NASA Astrophysics Data System (ADS)

    McKenna-Lawlor, S.; Gonçalves, P.; Keating, A.; Morgado, B.; Heynderickx, D.; Nieminen, P.; Santin, G.; Truscott, P.; Lei, F.; Foing, B.; Balaz, J.

    2012-03-01

    The ‘Mars Energetic Radiation Environment Models’ (dMEREM and eMEREM) recently developed for the European Space Agency are herein used to estimate, for the first time, background Galactic Cosmic Ray (GCR) radiation and flare related solar energetic particle (SEP) events at three candidate martian landing sites under conditions where particle arrival occurred at solar minimum (December, 2006) and solar maximum (April, 2002) during Solar Cycle 23. The three landing sites were selected on the basis that they are characterized by significantly different hydrological conditions and soil compositions. Energetic particle data sets recorded on orbit at Mars at the relevant times were incomplete because of gaps in the measurements due to operational constraints. Thus, in the present study, comprehensive near-Earth particle measurements made aboard the GOES spacecraft were used as proxies to estimate the overall particle doses at each perspective landing site, assuming in each case that the fluxes fell off as 1/r2 (where r is the helio-radial distance) and that good magnetic connectivity always prevailed. The results indicate that the particle radiation environment on Mars can vary according to the epoch concerned and the landing site selected. Particle estimations obtained using MEREM are in reasonable agreement, given the inherent differences between the models, with the related NASA Heavy Ion-Nucleon Transport Code for Space Radiation/HZETRN. Both sets of results indicated that, for short (30 days) stays, the atmosphere of Mars, in the cases of the SEPs studied and the then prevailing background galactic cosmic radiation, provided sufficient shielding at the planetary surface to maintain annual skin and blood forming organ/BFO dose levels below currently accepted ionizing radiation exposure limits. The threat of occurrence of a hard spectrum SEP during Cruise-Phase transfers to/from Mars over 400 days, combined with the associated cumulative effect of prolonged GCR exposure, poses an as yet unsolved hazard to prospective onboard personnel.

  15. Cosmogenic production rates and recoil loss effects in micrometeorites and interplanetary dust particles

    NASA Astrophysics Data System (ADS)

    Trappitsch, Reto; Leya, Ingo

    2013-02-01

    We present a purely physical model to determine cosmogenic production rates for noble gases and radionuclides in micrometeorites (MMs) and interplanetary dust particles (IDPs) by solar cosmic-rays (SCR) and galactic cosmic-rays (GCR) fully considering recoil loss effects. Our model is based on various nuclear model codes to calculate recoil cross sections, recoil ranges, and finally the percentages of the cosmogenic nuclides that are lost as a function of grain size, chemical composition of the grain, and the spectral distribution of the projectiles. The main advantage of our new model compared with earlier approaches is that we consider the entire SCR particle spectrum up to 240 MeV and not only single energy points. Recoil losses for GCR-produced nuclides are assumed to be equal to recoil losses for SCR-produced nuclides. Combining the model predictions with Poynting-Robertson orbital lifetimes, we calculate cosmic-ray exposure ages for recently studied MMs, cosmic spherules, and IDPs. The ages for MMs and the cosmic-spherule are in the range <2.2-233 Ma, which corresponds, according to the Poynting-Robertson drag, to orbital distances in the range 4.0-34 AU. For two IDPs, we determine exposure ages of longer than 900 Ma, which corresponds to orbital distances larger than 150 AU. The orbital distance in the range 4-6 AU for one MM and the cosmic spherule indicate an origin either in the asteroid belt or release from comets coming either from the Kuiper Belt or the Oort Cloud. Three of the studied MMs have orbital distances in the range 23-34 AU, clearly indicating a cometary origin, either from short-period comets from the Kuiper Belt or from the Oort Cloud. The two IDPs have orbital distances of more than 150 AU, indicating an origin from Oort Cloud comets.

  16. Space Environment (Natural and Induced)

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

    Considerable effort and improvement have been made in the study of ionizing radiation exposure occurring in various regions of space. Satellites and spacecrafts equipped with innovative instruments are continually refining particle data and providing more accurate information on the ionizing radiation environment. The major problem in accurate spectral definition of ionizing radiation appears to be the detailed energy spectra, especially at high energies, which is important parameter for accurate radiation risk assessment. Magnitude of risks posed by exposure to radiation in future space missions is subject to the accuracies of predictive forecast of event size of SPE, GCR environment, geomagnetic fields, and atmospheric radiation environment. Although heavy ion fragmentations and interactions are adequately resolved through laboratory study and model development, improvements in fragmentation cross sections for the light nuclei produced from HZE nuclei and their laboratory validation are still required to achieve the principal goal of planetary GCR simulation at a critical exposure site. More accurate prediction procedure for ionizing radiation environment can be made with a better understanding of the solar and space physics, fulfillment of required measurements for nuclear/atomic processes, and their validation and verification with spaceflights and heavy ion accelerators experiments. It is certainly true that the continued advancements in solar and space physics combining with physical measurements will strengthen the confidence of future manned exploration of solar system. Advancements in radiobiology will surely give the meaningful radiation hazard assessments for short and long term effects, by which appropriate and effective mitigation measures can be placed to ensure that humans safely live and work in the space, anywhere, anytime.

  17. Monte Carlo Simulation of Lunar Neutron Spectrum and Orbital Neutron Detection

    NASA Astrophysics Data System (ADS)

    SU, J.; Khachatryan, R.; Sadgeev, R.; Usikov, D.; Milikh, G. M.; Chin, G.

    2012-12-01

    The early detection of lunar neutrons produced by precipitation of galactic cosmic ray (GCR) particles in the upper layer of lunar soil goes back to Apollo Moon landing (Apollo 17) epoch. Since then it has been developed into its own type of remote sensing (Lunar Prospector/1998-1999; LRO/2009-till now), which is especially sensitive for singling out the information on presence of hydrogen (e.g. frozen water inside permanently shadowed craters) from neutron based cosmo-chemistry data. The final interpretation technique relies on comprehensive Monte Carlo simulation of neutron production by GCR and subsequent leakage from the Moon. Until now such extensive simulation was carried mostly with the use of MCNPX code [1], [2]. Here we report on the use of alternative MC code GEANT4, developed at CERN and offered as the open source software [3]. We believe that cross-comparison and inter-calibration of both codes will add more weight to the importance, versatility and reliability of Monte Carlo approach for neutron detection based planetary remote sensing. As a first step we compare basic results for neutron leakage from lunar soil (for several modeled elemental compositions). Then GEANT4 code was used to study the modification of neutron leakage in presence of top layer of dry and wet regolith. These data were applied to analysis of physical nature of SNRs (Suppressed Neutron Regions) found by LEND in polar areas of the Moon [4]. [1] Lawrence D.J. et al., (2006) JGR, 111, doi:10.1029/2005JE002637. [2] Mitrofanov I.G. et al. (2008) Astrobiology, 8, doi:10.1089/ast.207.0158. [3] Agostinelli S. et al., (2003) Nuclear Instr. Method in Phys. Res., 506A, 250-303. [4] Mitrofanov I.G. et al. (2010) Science, 330, doi:10.1126/science.1185696.

  18. Modeling the Action of Protons and Heavier Ions in Biological Targets: Nuclear Interactions in Hadrontherapy and Space Radiation Protection

    SciTech Connect

    Ballarini, F.; Ottolenghi, A.; Scannicchio, D. [Universita degli Studi di Pavia, Dipartimento di Fisica Nucleare e Teorica, Pavia (Italy); Istituto Nazionale di Fisica Nucleare (INFN) (Italy); Battistoni, G.; Pelliccioni, M.; Sala, P. [Istituto Nazionale di Fisica Nucleare (INFN) (Italy); Cerutti, F.; Gadioli, E. [Istituto Nazionale di Fisica Nucleare (INFN) (Italy); Universita degli Studi di Milano, Dipartimento di Fisica, Milan (Italy); Ferrari, A. [Istituto Nazionale di Fisica Nucleare (INFN) (Italy); CERN, Geneva (Switzerland); Garzelli, M. V. [Universita degli Studi di Milano, Dipartimento di Fisica, Milan (Italy); Parini, V. [Universita degli Studi di Pavia, Dipartimento di Fisica Nucleare e Teorica, Pavia (Italy); Pinsky, L. [University of Houston, Houston, TX (United States)

    2005-05-24

    Tumor treatment with protons and Carbon ions can allow for a better optimization of Tumor Control Probability and Normal Tissue Complication Probability, especially for radio-resistant tumors. Exposure to protons and heavier ions is also of concern for manned space missions such as future travels to the Moon and Mars. Nuclear reactions with the human body constituents, the beam line components (for hadrontherapy), and the spacecraft walls and shielding (for space radiation protection) can significantly modify the characteristics of the primary radiation field and thus the dose distributions in the various target tissues. In this context the FLUKA Monte Carlo transport code, integrated with radiobiological data and coupled with anthropomorphic phantoms, was applied to the characterization of therapeutic proton beams and the calculation of space radiation organ doses, with focus on the role of nuclear interactions. Besides absorbed and equivalent doses, distributions of 'biological' dose (modeled as the average number of DNA clustered lesions per cell induced in a given organ or tissue) were calculated as well. Concerning space radiation protection, exposure to Galactic Cosmic Rays (GCR) and Solar Particle Events (SPE) under different shielding conditions was simulated. Both for hadrontherapy and for space radiation exposure, nuclear reaction products were found to play a more important role for the equivalent and 'biological' dose than for the absorbed dose. Furthermore, while for SPEs the doses (both absorbed and equivalent/'biological') decreased dramatically by increasing the shield thickness, the GCR doses showed a slight shielding dependence. Overall, these examples of application of FLUKA to radiotherapy and radiation protection problems emphasized the need of further models and data, typically double-differential cross sections for nucleus-nucleus interactions at energies below a few hundred MeV/n.

  19. {sup 14}C depth profiles in Apollo 15 and 17 cores and lunar rock 68815

    SciTech Connect

    Jull, A.J.T.; Cloudt, S.; Donahue, D.J. [Univ. of Arizona, Tucson, AZ (United States). NSF Arizona AMS Facility] [Univ. of Arizona, Tucson, AZ (United States). NSF Arizona AMS Facility; Sisterson, J.M. [Harvard Univ., Cambridge, MA (United States). Harvard Cyclotron Lab.] [Harvard Univ., Cambridge, MA (United States). Harvard Cyclotron Lab.; Reedy, R.C. [Los Alamos National Lab., NM (United States)] [Los Alamos National Lab., NM (United States); Masarik, J. [Comenius Univ., Bratislava (Slovakia). Dept. of Nuclear Physics] [Comenius Univ., Bratislava (Slovakia). Dept. of Nuclear Physics

    1998-09-01

    Accelerator mass spectrometry (AMS) was used to measure the activity vs. depth profiles of {sup 14}C produced by both solar cosmic rays (SCR) and galactic cosmic rays (GCR) in Apollo 15 lunar cores 15001-6 and 15008, Apollo 17 core 76001, and lunar rock 68815. Calculated GCR production rates are in good agreement with {sup 14}C measurements at depths below {approximately}10 cm. Carbon-14 produced by solar protons was observed in the top few cm of the Apollo 15 cores and lunar rock 68815, with near-surface values as high as 66 dpm/kg in 68815. Only low levels of SCR-produced {sup 14}C were observed in the Apollo 17 core 76001. New cross sections for production of {sup 14}C by proton spallation on O, Si, Al, Mg, Fe, and Ni were measured using AMS. These cross sections are essential for the analysis of the measured {sup 14}C depth profiles. The best fit to the activity-depth profiles for solar-proton-produced {sup 14}C measured in the tops of both the Apollo 15 cores and 68815 was obtained for an exponential rigidity spectral shape R{sub 0} of 110--115 MV and a 4 {pi} flux (J{sub 10}, Ep > 10 MeV) of 103--108 protons/cm{sup 2}/s. These values of R{sub 0} are higher, indicating a harder rigidity, and the solar-proton fluxes are higher than those determined from {sup 10}Be, {sup 26}Al, and {sup 53}Mn measurements.

  20. An Overview of NASA's Risk of Cardiovascular Disease from Radiation Exposure

    NASA Technical Reports Server (NTRS)

    Patel, Zarana S.; Huff, Janice L.; Simonsen, Lisa C.

    2015-01-01

    The association between high doses of radiation exposure and cardiovascular damage is well established. Patients that have undergone radiotherapy for primary cancers of the head and neck and mediastinal regions have shown increased risk of heart and vascular damage and long-term development of radiation-induced heart disease [1]. In addition, recent meta-analyses of epidemiological data from atomic bomb survivors and nuclear industry workers has also shown that acute and chronic radiation exposures is strongly correlated with an increased risk of circulatory disease at doses above 0.5 Sv [2]. However, these analyses are confounded for lower doses by lifestyle factors, such as drinking, smoking, and obesity. The types of radiation found in the space environment are significantly more damaging than those found on Earth and include galactic cosmic radiation (GCR), solar particle events (SPEs), and trapped protons and electrons. In addition to the low-LET data, only a few studies have examined the effects of heavy ion radiation on atherosclerosis, and at lower, space-relevant doses, the association between exposure and cardiovascular pathology is more varied and unclear. Understanding the qualitative differences in biological responses produced by GCR compared to Earth-based radiation is a major focus of space radiation research and is imperative for accurate risk assessment for long duration space missions. Other knowledge gaps for the risk of radiation-induced cardiovascular disease include the existence of a dose threshold, low dose rate effects, and potential synergies with other spaceflight stressors. The Space Radiation Program Element within NASA's Human Research Program (HRP) is managing the research and risk mitigation strategies for these knowledge gaps. In this presentation, we will review the evidence and present an overview of the HRP Risk of Cardiovascular Disease and Other Degenerative Tissue Effects from Radiation Exposure.