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1

Development of a GCR Event-based Risk Model  

NASA Technical Reports Server (NTRS)

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

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

2009-01-01

2

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

NASA Astrophysics Data System (ADS)

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

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

3

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

NASA Technical Reports Server (NTRS)

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

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

2014-01-01

4

GCR environmental models I: Sensitivity analysis for GCR environments  

NASA Astrophysics Data System (ADS)

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.

Slaba, Tony C.; Blattnig, Steve R.

2014-04-01

5

GCR Environmental Models I: Sensitivity Analysis for GCR Environments  

NASA Technical Reports Server (NTRS)

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.

Slaba, Tony C.; Blattnig, Steve R.

2014-01-01

6

NIST GCR 02841 Between Invention  

E-print Network

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 1. The economic nature and value of technology-based innovations . . . . . . . . 27 A. TowardNIST GCR 02­841 Between Invention and Innovation An Analysis of Funding for Early-Stage Technology Development Prepared for Economic Assessment Office Advanced Technology Program National Institute

Magee, Joseph W.

7

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

PubMed

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

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

2011-02-01

8

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

NASA Astrophysics Data System (ADS)

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.

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

2014-04-01

9

Isotopic Effects in Nuclear Fragmentation and GCR Transport Problems  

NASA Technical Reports Server (NTRS)

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

Cucinotta, Francis A.

2002-01-01

10

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

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

11

Host Event Based Network Monitoring  

SciTech Connect

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.

Jonathan Chugg

2013-01-01

12

On the heliospheric characteristics and GCR intensity around solar minima  

NASA Astrophysics Data System (ADS)

Using the data on the solar (Wilcox Solar Obsevatory data and model) and heliospheric (OMNI data) magnetic field, the form of the current sheets and both the regular and current-sheet magnetic drift velocities are calculated for the periods around solar activity minima. The time behavior of different solar and heliospheric characteristics including the averaged over the longitude and longitude current-sheet drift velocity is compared with time profiles of the GCR intensity near the Earth in order to understand the main heliospheric factors fixing the latter. The particular attention is given to the development of the minimum phase of solar cycle 24.

Krainev, Mikhail; Kalinin, Mikhail

13

A complex regulatory element from the yeast gene ENO2 modulates GCR1-dependent transcriptional activation.  

PubMed Central

The GCR1 gene product is required for maximal transcription of many yeast genes including genes encoding glycolytic enzymes. Transcription of the yeast enolase gene ENO2 is reduced 50-fold in strains carrying a gcr1 null mutation. cis-acting sequences that are sufficient for GCR1-dependent regulation of ENO2 expression were identified by using an enhancerless CYC1 promoter which is not normally dependent on GCR1 for expression. A 60-bp ENO2 sequence that was sufficient to provide high-level, GCR1-dependent transcriptional activation of the CYC1 promoter was identified. This 60-bp element could be subdivided into a 30-bp sequence containing a novel RAP1-binding site and a GCR1-binding site which did not activate CYC1 transcription and a 30-bp sequence containing a novel enhancer element that conferred moderate levels of GCR1-independent transcriptional activation. The 60-bp CGCR1-dependent upstream activator sequence is located immediately downstream from previously mapped overlapping binding sites for the regulatory proteins ABFI and RAP1. Evidence is presented that the overlapping ABFI- and RAP1-binding sites function together with sequences that bind GCR1 and RAP1 to stage transcriptional activation of ENO2 expression. Images PMID:8455635

Willett, C E; Gelfman, C M; Holland, M J

1993-01-01

14

Event-based control for memristive systems  

NASA Astrophysics Data System (ADS)

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

Wen, Shiping; Zeng, Zhigang; Huang, Tingwen

2014-10-01

15

Landscape of international event-based biosurveillance  

PubMed Central

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

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

2010-01-01

16

Event-Based Science: Remote Sensing Activities  

NSDL National Science Digital Library

Event-Based Science is a new way to teach science by using newsworthy events to establish the relevance of science topics. Interviews, photographs, web pages, and inquiry-based science activities create a desire to know more about these topics. This collection of activities deals with such topics as damage to agriculture caused by drought, the recovery of forests after a fire, and flooding and the migration of river channels. There are also activities on earthquake hazards, hurricane tracking, the impacts of oil spills, and how to plan an escape route to avoid a volcanic mudflow. Each of these activities uses NASA imagery, in particular LandSat images.

2007-03-15

17

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

PubMed Central

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

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

2013-01-01

18

An Event Based Approach To Situational Representation  

E-print Network

Many application domains require representing interrelated real-world activities and/or evolving physical phenomena. In the crisis response domain, for instance, one may be interested in representing the state of the unfolding crisis (e.g., forest fire), the progress of the response activities such as evacuation and traffic control, and the state of the crisis site(s). Such a situation representation can then be used to support a multitude of applications including situation monitoring, analysis, and planning. In this paper, we make a case for an event based representation of situations where events are defined to be domain-specific significant occurrences in space and time. We argue that events offer a unifying and powerful abstraction to building situational awareness applications. We identify challenges in building an Event Management System (EMS) for which traditional data and knowledge management systems prove to be limited and suggest possible directions and technologies to address the challenges.

Ashish, Naveen; Mehrotra, Sharad; Venkatasubramanian, Nalini

2009-01-01

19

GCR Simulator Reference Field and a Spectral Approach for Laboratory Simulation  

NASA Technical Reports Server (NTRS)

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

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

2015-01-01

20

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

PubMed Central

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

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

2015-01-01

21

Mutations in Gcr3, a Gene Involved in the Expression of Glycolytic Genes in Saccharomyces Cerevisiae, Suppress the Temperature-Sensitive Growth of Hpr1 Mutants  

PubMed Central

To study the functions of DNA topoisomerase I and Hpr1 protein, a suppressor mutant of the temperature-sensitive growth of an hpr1 top1-5(ts) double mutant was isolated. The isolated triple mutant showed cold-sensitive growth. By complementation of this phenotype, the suppressor gene was cloned. DNA sequencing showed it to be GCR3, a gene involved in the expression of glycolytic genes. Further analysis showed that gcr3 mutations also suppressed the temperature-sensitive growth of hpr1 single mutants. Experiments with gcr3 truncation mutants also suggested a genetic interaction between GCR3 and HPR1. The fact that top1 suppressed the growth defect of gcr3 suggested an interaction between those two genes also. Plasmid DNA isolated from gcr3 mutants was significantly more negatively supercoiled than normal, suggesting that Gcr3 protein, like topoisomerase I and Hpr1p, affects chromatin structure, perhaps during transcription. PMID:8846890

Uemura, H.; Pandit, S.; Jigami, Y.; Sternglanz, R.

1996-01-01

22

Taxonomy of Distributed Event-Based Programming Systems  

Microsoft Academic Search

Event-based middleware is currently being applied for application component integration in a range of application domains. As a result, a variety of event services have been proposed to address different requirements. In order to aid the understanding of the relationships between these systems, this paper presents a taxonomy of distributed event-based programming systems. The taxonomy is structured as a hierarchy

René Meier; Vinny Cahill

2002-01-01

23

Discrete-event based simulation conceptual modeling of systems biology  

Microsoft Academic Search

The protein production from DNA to protein via RNA is a very complicated process, which could be called central dogma. In this paper, we used event based simulation to model, simulate, analyze and specify the three main processes that are involved in the process of protein production: replication, transcription, and translation. The whole control flow of event-based simulation is composed

Joe W. Yeol; Issac Barjis; Yeong S. Ryu; Joseph Barjis

2005-01-01

24

Event-Based Approach to Modelling Dynamic Architecture  

E-print Network

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

Paris-Sud XI, Université de

25

Multi-field coupled numerical simulation of hot reversible rolling process of GCr15 steel rod  

NASA Astrophysics Data System (ADS)

In this paper, based on rolling technology of hot reversible rolling mill, a multi-filed coupled finite element (FE) model of hot reversible rolling process of large dimension cross-section GCr15 steel rod is established. Thermal, mechanical and microstructural phenomena during the rolling process are coupled in the model. By employing grain growth experiment, double and single hit hot compression experiments, the austenite grain size growth mathematical model and recrystallization behavior mathematical models are determined. And a designed subprogram is coupled in the FE model. Actual hot reversible rolling process of GCr15 steel is simulated using the model and the distribution and evolution of different filed-variables, such as temperature, effective strain and austenite grain size are obtained. To verify the model predictions, hot rolling experiments are carried out and the temperature and microstructure of the rolling metal are compared with the predicted results. The comparison between the two sets of data shows a good agreement.

Gu, Sendong; Zhang, Liwen; Ruan, Jinhua; Mei, Hongyu; Zhen, Yu; Shi, Xinhua

2013-05-01

26

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

NASA Technical Reports Server (NTRS)

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

ONeill, P. M.

2007-01-01

27

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

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

28

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

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

29

The GCR1, GPA1, PRN1, NF-Y signal chain mediates both blue light and abscisic acid responses in Arabidopsis.  

PubMed

Different classes of biotic (e.g. plant hormones) and abiotic (e.g. different wavelengths of light) signals act through specific signal transduction mechanisms to coordinate higher plant development. While a great deal of progress has been made, full signal transduction chains have not yet been described for most blue light- or abscisic acid-mediated events. Based on data derived from T-DNA insertion mutants and yeast (Saccharomyces cerevisiae) two-hybrid and coprecipitation assays, we report a signal transduction chain shared by blue light and abscisic acid leading to light-harvesting chlorophyll a/b-binding protein expression in etiolated Arabidopsis (Arabidopsis thaliana) seedlings. The chain consists of GCR1 (the sole Arabidopsis protein coding for a potential G-protein-coupled receptor), GPA1 (the sole Arabidopsis Galpha-subunit), Pirin1 (PRN1; one of four members of an iron-containing subgroup of the cupin superfamily), and a nuclear factor Y heterotrimer comprised of A5, B9, and possibly C9. We also demonstrate that this mechanism is present in imbibed seeds wherein it affects germination rate. PMID:17322342

Warpeha, Katherine M; Upadhyay, Snehali; Yeh, Jennifer; Adamiak, Julia; Hawkins, Samuel I; Lapik, Yevgeniya R; Anderson, Mary Beth; Kaufman, Lon S

2007-04-01

30

Event-Based Learning: Educational and Technological Perspectives  

Microsoft Academic Search

Teachers have traditionally introduced current events in the classroom to leverage news topics relevant to the curriculum; however, to my knowledge no studies have attempted to provide a comprehensive research view on these event-related teaching activities. This paper presents an introductory event-based learning analysis from educational and technological research perspectives. This research effort provides a broad characterization of event-based learning

Sebastian de la Chica

31

Asynchronous visual event-based time-to-contact  

PubMed Central

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

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

2014-01-01

32

Efficient transcription of the glycolytic gene ADH1 and three translational component genes requires the GCR1 product, which can act through TUF/GRF/RAP binding sites.  

PubMed Central

Glycolytic gene expression in Saccharomyces cerevisiae is thought to be activated by the GCR and TUF proteins. We tested the hypothesis that GCR function is mediated by TUF/GRF/RAP binding sites (UASRPG elements). We found that UASRPG-dependent activation of a heterologous gene and transcription of ADH1, TEF1, TEF2, and RP59 were sensitive to GCR1 disruption. GCR is not required for TUF/GRF/RAP expression or in vitro DNA-binding activity. Images PMID:2405258

Santangelo, G M; Tornow, J

1990-01-01

33

Galactic Cosmic Ray (GCR) Model of Titan and Formation of HCNO Exobiological Molecules  

NASA Astrophysics Data System (ADS)

Saturn as a system has two very exotic moons Titan and Enceladus. Space radiation effects at both moons, and as coupled by the Saturn magnetosphere, could lead to the evolution of exobiological models at Titan composed of HCNO molecules. At Titan Cassini discovered that 1) keV oxygen ions, evidently from Enceladus, are bombarding Titan’s upper atmosphere (Hartle et al., 2006a,b) and 2) heavy positive and negative ions exist in significant abundances within Titan’s upper atmosphere (Coates et al., 2007). Polycyclic Aromatic Hydrocarbons (PAHs) and fullerenes could form in Titan’s ionosphere. Laboratory measurements indicate that fullerenes, which are hollow carbon shells, can trap the keV oxygen ions. Clustering of the fullerenes with PAHs and the dominant nitrogen molecules could form larger aerosols enriched in trapped oxygen. Aerosol precipitation could then convey these chemically complex structures deeper into the atmosphere and to the moon surface. We estimate that GCR irradiation should dominate the chemical processing of the aerosols on the surface into more complex organic forms such as tholins and amino acids. To further quantify our results, we have developed an advanced model of GCR interaction with Titan’s atmosphere, surface and sub-surface. The model shows dose rates ~ 8x10-6 ergs/cm2/s at the surface which is ~ 4.2x10-9 erg/gm/s for tholin mass density ~ 1.8 gm/cm3. The GCR are found to penetrate ~ 50-100 m below the surface and may therefore also reach the bottom of Titan’s methane-ethane lakes. Reggie Hudson et al. (2008) showed that G-factor ~ 0.001 for Glycine. They used pure Acetonitrile CH3CN ices with very small water levels ~ 0.01% for O. So using G ~ 0.001 and GCR surface energy flux noted above at Titan’s surface we estimate abundance levels ~ 2-10 ppb of amino acids such as Glycine over 450 Myr period. Therefore, we conclude that this synergy of Saturn system, exogenic irradiation, and molecular processes provide a potential pathway for accumulation of prebiotic chemicals on the surface of Titan.

Sittler, Edward C.; Cooper, J. F.

2014-01-01

34

Asynchronous event-based corner detection and matching.  

PubMed

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

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

2015-06-01

35

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

NASA Technical Reports Server (NTRS)

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?

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

2007-01-01

36

Elemental GCR Observations during the 2009-2010 Solar Minimum Period  

NASA Technical Reports Server (NTRS)

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

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

2013-01-01

37

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

NASA Technical Reports Server (NTRS)

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

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

2009-01-01

38

University of Oregon | Public and Government Affairs | 541-346-5020 | gcr@uoregon.edu |11/15/12 | p.1 Collaborations  

E-print Network

University of Oregon | Public and Government Affairs | 541-346-5020 | gcr@uoregon.edu |11/15/12 | p Treasurer's investment management, debt issuance, and debt management functions, and they monitor compliance and the Chancellor's Office or #12;University of Oregon | Public and Government Affairs | 541-346-5020 | gcr

Oregon, University of

39

Spatiotemporal features for asynchronous event-based data.  

PubMed

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

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

2015-01-01

40

STEAM: event-based middleware for wireless ad hoc networks  

Microsoft Academic Search

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

Rene Meier; Vinny Cahill

2002-01-01

41

Dynamic Event-Based Access Control as Term Rewriting  

E-print Network

of access control policies defined in terms of our model, and direct implementa- tions for access controlDynamic Event-Based Access Control as Term Rewriting Clara Bertolissi2 , Maribel Fern´andez1. Despite the widespread adoption of Role-based Access Con- trol (RBAC) models, new access control models

Fernández, Maribel

42

Event based indexing of broadcasted sports video by intermodal collaboration  

Microsoft Academic Search

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

Noboru Babaguchi; Yoshihiko Kawai; Tadahiro Kitahashi

2002-01-01

43

Event-Based Performance Analysis Steven P. Reiss  

E-print Network

resources based on two-level calls, that is, instead of looking at all instances of routine R, they separate-thread analysis of resource utilization. Still other tools look at specific items in a complex system. For examEvent-Based Performance Analysis Steven P. Reiss Department of Computer Science Brown University

Reiss, Steven P.

44

Spatiotemporal features for asynchronous event-based data  

PubMed Central

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.

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

2015-01-01

45

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

SciTech Connect

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.

Battistoni, G.; /Milan U. /INFN, Milan; Cerutti, F.; /CERN; Fasso, A.; /SLAC; Ferrari, A.; /CERN; Garzelli, M.V.; /Milan U. /INFN, Milan; Lantz, M.; /Goteborg, ITP; Muraro, S. /Milan U. /INFN, Milan; Pinsky, L.S.; /Houston U.; Ranft, J.; /Siegen U.; Roesler, S.; /CERN; Sala, P.R.; /Milan U. /INFN, Milan; ,

2009-06-16

46

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

SciTech Connect

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.

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

47

Secondary Cosmic Ray particles due to GCR interactions in the Earth's atmosphere  

E-print Network

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.

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

2007-11-13

48

GCR flux reconstruction during the last three centuries validated by the Ti-44 in meteorites and Be-10 in ice  

NASA Astrophysics Data System (ADS)

In a previous work [1] we deduced that during prolonged minima of solar activity since 1700 the galactic cosmic rays (GCR) flux was much higher (˜2 times) respect to what we can infer from GCR modulation deduced solely by the Sunspot Number series. This flux was higher respect to what we observe in the last decades by Neutron Monitor or balloon and spacecraft-borne detectors and confirmed by the three fresh-fall meteorites that we have measured during solar cycle 22. Recently we have deduced the GCR annual mean spectra for the last 300 years [2], starting from the open solar magnetic flux proposed by Solanki et al. [3]. Utilizing the GCR flux we have calculated the 44Ti (T1/2 = 59.2 y) activity in meteorites taking into account the cross sections for its production from the main target element Fe and Ni. We compare the calculated activity with our measurements of the cosmogenic 44Ti in different chondrites fell in the period 1810-1997. The results are in close agreement both in phase and amplitude. The same procedure has been adopted for calculating the production rate of 10Be in atmosphere. Normalizing to the concentration in ice in the solar cycles 20 and 21 we obtain a good agreement with the 10Be profile in Dye3 core [4]. These results demonstrate that our inference of the GCR flux in the past 300 years is reliable. [1] Bonino G., Cini Castagnoli G., Bhandari N., Taricco C., textit {Science}, 270, 1648, 1995 [2] Bonino G., Cini Castagnoli G., Cane D., Taricco C. and Bhandari N., textit {Proc. XXVII Intern. Cosmic Ray Conf.} (Hamburg, 2001) 3769-3772. [3] Solanki S.K., Schüssler M. and Fligge M.,Nature, 408, 445, 2000 [4] Beer J. et al., private communication

Cini Castagnoli, G.; Cane, D.; Taricco, C.; Bhandari, N.

2003-04-01

49

Mars Science Laboratory; A Model for Event-Based EPO  

NASA Astrophysics Data System (ADS)

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.

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

2012-10-01

50

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

NASA Technical Reports Server (NTRS)

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

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

1999-01-01

51

Event-Based Simulation of Quantum Physics Experiments  

NASA Astrophysics Data System (ADS)

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.

Michielsen, Kristel; de Raedt, Hans

2015-10-01

52

Event-based simulation of quantum physics experiments  

E-print Network

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 one-by-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.

Kristel Michielsen; Hans De Raedt

2014-08-08

53

Event-Based Science: Remote-Sensing Activities  

NSDL National Science Digital Library

These activities enable students to use remotely-sensed data- as they tackle the real-world problems and tasks found in existing Event-Based Science (EBS) modules. Remotely-sensed data are employed as an integral part of both the presentation of Earth system science concepts, and in the solutions to real-world problems. The activities emphasize the use of NASA remote-sensing data from satellites and sensors including: Landsat, GOES, and MODIS, and SeaWiFS. The EBS remote-sensing activities enhance EBS modules, including: Blight! Earthquake! Fire! Flood! Hurricane! Oil Spill! and Volcano!

2011-01-01

54

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

SciTech Connect

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

Tuninetti, G. (Ansaldo S.p.A., Genoa (Italy). Research Div.); Botta, E.; Criscuolo, C.; Riscossa, P. (Ansaldo S.p.A., Genoa (Italy). Nuclear Div.); Giammanco, F. (Pisa Univ. (Italy). Dipt. di Fisica); Rosa-Clot, M. (Florence Univ. (Italy). Dipt. di Fisica)

1989-04-20

55

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

NASA Technical Reports Server (NTRS)

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

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

1998-01-01

56

SloR modulation of the Streptococcus mutans acid tolerance response involves the GcrR response regulator as an essential intermediary.  

PubMed

Streptococcus mutans, the primary causative agent of human dental caries, grows as a biofilm on the tooth surface, where it metabolizes dietary carbohydrates and generates acid byproducts that demineralize tooth enamel. A drop in plaque pH stimulates an adaptive acid-tolerance response (ATR) in this oral pathogen that allows it to survive acid challenge at pHs as low as 3.0. In the present study, we describe the growth of an S. mutans mutant, GMS901, that harbours an insertion-deletion mutation in gcrR, a gene that encodes a transcriptional regulatory protein. The mutant is acid-sensitive and significantly compromised in its ATR relative to the UA159 wild-type progenitor strain. Consistent with these findings are the results of real-time quantitative RT-PCR (qRT-PCR) experiments that support the GcrR-regulated expression of known ATR genes, including atpA/E and ffh. Although we observed gcrR transcription that was not responsive to acidic pH, we did note a significant increase in gcrR expression when S. mutans cells were grown in a manganese-restricted medium. Interestingly, the results of gel mobility shift assays indicate that the S. mutans SloR metalloregulatory protein is a potential regulator of gcrR by virtue of its manganese-dependent binding to the gcrR promoter region, and expression studies support the hypothesis that sloR transcription is responsive to manganese deprivation and acidic pH. Taking these results together, we propose that SloR-Mn modulates S. mutans gcrR expression as part of a general stress response, and that GcrR acts downstream of SloR to control the ATR. PMID:18375805

Dunning, Daniel W; McCall, Lathan W; Powell, William F; Arscott, W Tristram; McConocha, Erin M; McClurg, Cheryl J; Goodman, Steven D; Spatafora, Grace A

2008-04-01

57

11/8/2006 Christian Tominski -Event-Based Visualization for User-Centered Visual Analysis  

E-print Network

11/8/2006 Christian Tominski - Event-Based Visualization for User-Centered Visual Analysis 1 Event-Based Visualization for User-Centered Visual Analysis Christian Tominski University of Rostock November 8th, 2006 #12;11/8/2006 Christian Tominski - Event-Based Visualization for User-Centered Visual Analysis 2 Classic vs. Event

Tominski, Christian

58

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)

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.

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

59

A 3D Monte Carlo model of radiation affecting cells, and its application to neuronal cells and GCR irradiation  

NASA Astrophysics Data System (ADS)

A 3D Monte Carlo model of radiation transport in matter is applied to study the effect of heavy ion radiation on human neuronal cells. Central nervous system effects, including cognitive impairment, are suspected from the heavy ion component of galactic cosmic radiation (GCR) during space missions. The model can count, for instance, the number of direct hits from ions, which will have the most affect on the cells. For comparison, the remote hits, which are received through ?-rays from the projectile traversing space outside the volume of the cell, are also simulated and their contribution is estimated. To simulate tissue effects from irradiation, cellular matrices of neuronal cells, which were derived from confocal microscopy, were simulated in our model. To produce this realistic model of the brain tissue, image segmentation was used to identify cells in the images of cells cultures. The segmented cells were inserted pixel by pixel into the modeled physical space, which represents a volume of interacting cells with periodic boundary conditions (PBCs). PBCs were used to extrapolate the model results to the macroscopic tissue structures. Specific spatial patterns for cell apoptosis are expected from GCR, as heavy ions produce concentrated damage along their trajectories. The apoptotic cell patterns were modeled based on the action cross sections for apoptosis, which were estimated from the available experimental data. The cell patterns were characterized with an autocorrelation function, which values are higher for non-random cell patterns, and the values of the autocorrelation function were compared for X rays and Fe ion irradiations. The autocorrelation function indicates the directionality effects present in apoptotic neuronal cells from GCR.

Ponomarev, Artem; Sundaresan, Alamelu; Kim, Angela; Vazquez, Marcelo E.; Guida, Peter; Kim, Myung-Hee; Cucinotta, Francis A.

60

Event-based user classification in Weibo media.  

PubMed

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

Guo, Liang; Wang, Wendong; Cheng, Shiduan; Que, Xirong

2014-01-01

61

Event-Based User Classification in Weibo Media  

PubMed Central

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

Wang, Wendong; Cheng, Shiduan; Que, Xirong

2014-01-01

62

Event-based internet biosurveillance: relation to epidemiological observation  

PubMed Central

Background The World Health Organization (WHO) collects and publishes surveillance data and statistics for select diseases, but traditional methods of gathering such data are time and labor intensive. Event-based biosurveillance, which utilizes a variety of Internet sources, complements traditional surveillance. In this study we assess the reliability of Internet biosurveillance and evaluate disease-specific alert criteria against epidemiological data. Methods We reviewed and compared WHO epidemiological data and Argus biosurveillance system data for pandemic (H1N1) 2009 (April 2009 – January 2010) from 8 regions and 122 countries to: identify reliable alert criteria among 15 Argus-defined categories; determine the degree of data correlation for disease progression; and assess timeliness of Internet information. Results Argus generated a total of 1,580 unique alerts; 5 alert categories generated statistically significant (p?

2012-01-01

63

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

PubMed Central

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

Williams, Gareth

2015-01-01

64

Rainfall—runoff response, event-based runoff coefficients and hydrograph separation  

Microsoft Academic Search

Event-based runoff coefficients can provide information on watershed response. They are useful for catchment comparison to understand how different landscapes “filter” rainfall into event-based runoff and to explain the observed differences with catchment characteristics and related runoff mechanisms. However, the big drawback of this important parameter is the lack of a standard hydrograph separation method preceding its calculation. Event-based runoff

THERESA BLUME; ERWIN ZEHE; AXEL BRONSTERT

2007-01-01

65

Sequences within an upstream activation site in the yeast enolase gene ENO2 modulate repression of ENO2 expression in strains carrying a null mutation in the positive regulatory gene GCR1.  

PubMed Central

Transcription of the yeast enolase gene ENO2 is reduced 20- to 50-fold in strains carrying a null mutation in the positive regulatory gene GCR1. A small deletion mutation within one of two upstream activation sites (UAS elements) in the 5'-flanking region of ENO2 permitted wild-type levels of ENO2 gene expression in a strain carrying the gcr1 null mutation. These data show that sequences required for UAS element activity in GCR1 strains were required to repress ENO2 expression in a gcr1 strain. Protein factors that specifically bound to this UAS/repression site were identified. We show that the DNA-binding protein ABFI (autonomously replicating sequence-binding factor) is the major protein which binds the UAS/repression site. Minor DNA-binding activities that interact specifically with the UAS/repression site were also identified and may correspond to proteolytic breakdown products of ABFI. None of the observed binding activities were encoded by the GCR1 structural gene. A double-stranded oligonucleotide that included the UAS/repression site activated transcription of UAS-less ENO1 and ENO2 gene cassettes in vivo to wild-type levels in strains carrying the GCR1 allele as well as the gcr1 null mutation. These latter data show that the UAS/repression site is sufficient for transcriptional activation but is not sufficient to repress transcription of the enolase genes in a gcr1 genetic background. Images PMID:2201904

Holland, J P; Brindle, P K; Holland, M J

1990-01-01

66

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

ERIC Educational Resources Information Center

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…

Wright, Russell G.

67

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

ERIC Educational Resources Information Center

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,…

Wright, Russell G.

68

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

ERIC Educational Resources Information Center

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…

Wright, Russell G.

69

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

ERIC Educational Resources Information Center

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,…

Wright, Russell G.

70

Event-based Approach to Money Laundering Data Analysis and Visualization  

E-print Network

Event-based Approach to Money Laundering Data Analysis and Visualization Tat-Man Cheong Faculty, an event-based approach to money laundering data analysis and visualization is proposed in this paper. The effectiveness of the proposed method is demonstrated on a money laundering case from Taiwan. Categories

Si, Yain Whar "Lawrence"

71

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

ERIC Educational Resources Information Center

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…

Wright, Russell G.

72

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

ERIC Educational Resources Information Center

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

Wright, Russell G.

73

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

ERIC Educational Resources Information Center

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

Wright, Russell G.

74

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

ERIC Educational Resources Information Center

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…

Wright, Russell G.

75

Self-Calibrating Marker Tracking in 3D with Event-Based Vision Sensors  

E-print Network

-Tilt Vision Sensors (red) to track an active marker at unknown absolute coordinates X, Y, Z (blue). Right vision sensors (eDVS) independently track a high frequency flickering LED in their respective 2D angular coordinates (blue). 2 Event Based Stimuli Tracking in Sensor Coordinate Frame 2.1 Event Based Embedded Vision

Kuehnlenz, Kolja

76

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

ERIC Educational Resources Information Center

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

Wright, Russell G.

77

Understanding JavaScript Event-Based Interactions Saba Alimadadi Sheldon Sequeira Ali Mesbah Karthik Pattabiraman  

E-print Network

Understanding JavaScript Event-Based Interactions Saba Alimadadi Sheldon Sequeira Ali Mesbah of the JavaScript language. We propose a generic technique for capturing low-level event-based interactions, related JavaScript code executions, and their impact on the dynamic DOM state. Our approach, implemented

Pulfrey, David L.

78

Toxic Leak!: An Event-Based Science Module. Teacher's Guide. Groundwater Module.  

ERIC Educational Resources Information Center

This book is designed for middle school earth science teachers to help their students learn about problems with toxic leaking 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…

Wright, Russell G.

79

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

ERIC Educational Resources Information Center

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,…

Wright, Russell G.

80

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

ERIC Educational Resources Information Center

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…

Wright, Russell G.

81

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

ERIC Educational Resources Information Center

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,…

Wright, Russell G.

82

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

ERIC Educational Resources Information Center

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…

Wright, Russell G.

83

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

performance? (5) List at least four safety precautions during laser operation. #12;(6) List at least threeNd: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

Turro, Claudia

84

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

SciTech Connect

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.

NONE

1995-03-31

85

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

PubMed Central

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

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

86

Are Time- and Event-based Prospective Memory Comparably Affected in HIV Infection?†  

PubMed Central

According to the multi-process theory of prospective memory (ProM), time-based tasks rely more heavily on strategic processes dependent on prefrontal systems than do event-based tasks. Given the prominent frontostriatal pathophysiology of HIV infection, one would expect HIV-infected individuals to demonstrate greater deficits in time-based versus event-based ProM. However, the two prior studies examining this question have produced variable results. We evaluated this hypothesis in 143 individuals with HIV infection and 43 demographically similar seronegative adults (HIV?) who completed the research version of the Memory for Intentions Screening Test, which yields parallel subscales of time- and event-based ProM. Results showed main effects of HIV serostatus and cue type, but no interaction between serostatus and cue. Planned pair-wise comparisons showed a significant effect of HIV on time-based ProM and a trend-level effect on event-based ProM that was driven primarily by the subset of participants with HIV-associated neurocognitive disorders. Nevertheless, time-based ProM was more strongly correlated with measures of executive functions, attention/working memory, and verbal fluency in HIV-infected persons. Although HIV-associated deficits in time- and event-based ProM appear to be of comparable severity, the cognitive architecture of time-based ProM may be more strongly influenced by strategic monitoring and retrieval processes. PMID:21459901

Zogg, Jennifer B.; Woods, Steven Paul; Weber, Erica; Doyle, Katie; Grant, Igor; Atkinson, J. Hampton; Ellis, Ronald J.; McCutchan, J. Allen; Marcotte, Thomas D.; Hale, Braden R.; Ellis, Ronald J.; McCutchan, J. Allen; Letendre, Scott; Capparelli, Edmund; Schrier, Rachel; Heaton, Robert K.; Cherner, Mariana; Moore, David J.; Jernigan, Terry; Fennema-Notestine, Christine; Archibald, Sarah L.; Hesselink, John; Annese, Jacopo; Taylor, Michael J.; Masliah, Eliezer; Everall, Ian; Langford, T. Dianne; Richman, Douglas; Smith, David M.; McCutchan, J. Allen; Everall, Ian; Lipton, Stuart; McCutchan, J. Allen; Atkinson, J. Hampton; Ellis, Ronald J.; Letendre, Scott; Atkinson, J. Hampton; von Jaeger, Rodney; Gamst, Anthony C.; Cushman, Clint; Masys, Daniel R.; Abramson, Ian; Ake, Christopher; Vaida, Florin

2011-01-01

87

An Event-Based Approach to Distributed Diagnosis of Continuous Systems  

NASA Technical Reports Server (NTRS)

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.

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

2010-01-01

88

GCR Dose Rate Observed in Lunar Orbit During the Transition from Solar Cycle 23 to Cycle 24  

NASA Astrophysics Data System (ADS)

The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument aboard the Lunar Reconnaissance Orbiter (LRO) spacecraft has been measuring the charged particle radiation environment in low-lunar orbit since 2009-06-27. CRaTER’s charged particle measurements are made with six fully-depleted Si solid state detectors organized into three coaxially aligned pairs consisting of a “thin” (~150 ?m) and “thick” (~1000 ?m) detector. The detector pairs are mounted in a telescope configuration with the adjacent pairs separated by plastic absorbers; the two outermost detectors forming the telescope’s apertures are covered by thin Al end-caps. LRO’s nominal operations are conducted in an ~50 km altitude circular polar orbit with the spacecraft’s attitude oriented to keep the science instruments in a nadir staring direction. This orientation places CRaTER’s longitudinal axis parallel to a radial originating from the center of the Moon, with one pair of detectors facing zenith, another pair facing nadir, with the middle pair shielded on both sides by the plastic absorbers. The daily absorbed dose measured by each detector was computed from the detector’s PHA spectra; for the thin detectors this corresponds to particle interactions with lineal energies between ~1.59 to 1490 keV/ ?m and 0.0970 to 63.1 keV/ ?m for particle interactions in the thick detectors. During the interval 2009-09-16 to 2010-02-28 the average dose rate (in Si) measured by the three thin detectors were 186 ?Gy/day, 161 ?Gy/day, and 171 ?Gy/day for the zenith-facing, plastic-shielded middle, and nadir-facing detectors, respectively. The corresponding dose rates for the three thick detectors were 255 ?Gy/day, 248 ?Gy/day, and 253 ?Gy/day. These dose rates are in good agreement with the average dose rate of 211 ?Gy/day reported for the RADOM instrument on the Chandrayyan-1 mission operating in a 100 km circular polar lunar orbit during the period 2008-11-13 to 2008-12-24. In this analysis period the peak dose rates measured by the CRaTER detectors occurred during the period 2009-12-31 to 2010-01-07 followed by the onset of gradual declines. During this period the Thule neutron monitor count rate, a proxy for moderate-to-high-energy GCR proton flux at the top of the Earth’s atmosphere, peaked during the period 2009-10-01 to 2009-12-31 before undergoing a sharp decrease through the remainder of the analysis period. Assuming the peak in the Thule neutron monitor count rate marks the deepest point of solar cycle 23 and the beginning of an unabated increase in solar activity with the onset of cycle 24, these CRaTER measurements may represent the maximum GCR dose rates directly measured since the inception of space-based measurements more than 50 years ago.

Golightly, M. J.; Schwadron, N. A.; Spence, H. E.; Wilson, J. K.; Case, A.; Townsend, L.; Kasper, J. C.; Blake, J.; Looper, M. D.; Mazur, J.

2010-12-01

89

NASA Space Radiation Program Integrative Risk Model Toolkit  

NASA Technical Reports Server (NTRS)

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

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

2015-01-01

90

Event-Based Data Control in Healthcare Jatinder Singh and Jean Bacon  

E-print Network

Event-Based Data Control in Healthcare Jatinder Singh and Jean Bacon Computer Laboratory University Keywords Data Control, Healthcare, Middleware, Publish/Subscribe 1. HEALTHCARE DIRECTIONS Health services, such a care model is unsustainable. Therefore, there is a global push to reform health services, to improve

Cambridge, University of

91

Exploiting an event-based infrastructure to develop complex distributed systems  

Microsoft Academic Search

The development of complex distributed systems demands for the creation of suitable architectural styles (or paradigms) and related run-time infrastructures. An emerging style that is receiving increasing attention is based o n the notion of event. In an event-based architecture, distributed software components interact by generating and consuming events. The occurrence of an event in a component (called source) is

Gianpaolo Cugola; Elisabetta Di Nitto; Alfonso Fuggetta

1998-01-01

92

The JEDI Event-Based Infrastructure and Its Application to the Development of the OPSS WFMS  

Microsoft Academic Search

The development of complex distributed systems demands for the creation of suitable architectural styles (or paradigms) and related run-time infrastructures. An emerging style that is receiving increasing attention is based on the notion of event. In an event-based architecture, distributed software components interact by generating and consuming events. An event is the occu r- rence of some state change in

Gianpaolo Cugola; Elisabetta Di Nitto; Alfonso Fuggetta

2001-01-01

93

Anticipating railway operation disruption events based on the analysis of discrete-event diagnostic data  

E-print Network

Anticipating railway operation disruption events based on the analysis of discrete-event diagnostic increases operating costs and reduces patronage. In railway systems reliability is significantly influenced on reliability and availability, many advanced railway systems and components include monitoring and diagnostic

Paris-Sud XI, Université de

94

Spatio-Temporal and Events Based Analysis of Topic Popularity in Twitter  

E-print Network

and spatial behavior of popular topics and support our hypotheses by showing that non-popular topics displaySpatio-Temporal and Events Based Analysis of Topic Popularity in Twitter Sebastien Ardon Amitabha- lion topics that include both popular and less popular to- pics. On a data set containing approximately

Bagchi, Amitabha

95

An event-based model of superspreading in epidemics Alex Jamesa  

E-print Network

are explored more comprehensively in Section 4. 2 A simple mechanistic SS model Discrete-time branching of susceptibles in each time step (generation), and the epidemic spreads generation-by-generation. IndividualsAn event-based model of superspreading in epidemics Alex Jamesa , Jonathan W. Pitchfordb

James, Alex

96

Nuclear power installations. [GCR  

Microsoft Academic Search

In a nuclear power installation comprising a fluid-cooled nuclear reactor, main boilers and main coolant circulators driven by steam turbines to circulate coolant fluid through the reactor core and the main boilers, the circulator-driving steam turbines are driven by steam from auxiliary boilers which are also heated by the hot reactor coolant. This steam, after then being reheated by the

1976-01-01

97

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

PubMed Central

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

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

2009-01-01

98

An Energy Efficient Layer for Event-Based Communications in Web-of-Things Frameworks  

E-print Network

to the concept of Internet-of-Things (IoT) [1]. This idiom includes the concept of Wireless Sensor Networks (WSN the energy consumption of things connected to the Internet through Wi-Fi. We rely on the Web-of-ThingsAn Energy Efficient Layer for Event-Based Communications in Web-of-Things Frameworks Gérôme Bovet1

Boyer, Edmond

99

The Link Between Alcohol Use and Aggression Toward Sexual Minorities: An Event-Based Analysis  

Microsoft Academic Search

The current study used an event-based assessment approach to examine the day-to-day relationship between heterosexual men's alcohol consumption and perpetration of aggression toward sexual minorities. Participants were 199 heterosexual drinking men between the ages of 18–30 who completed (1) separate timeline followback interviews to assess alcohol use and aggression toward sexual minorities during the past year, and (2) written self-report

Dominic J. Parrott; Kathryn E. Gallagher; Wilson Vincent; Roger Bakeman

2010-01-01

100

Event-Based Prospective Memory and Executive Control of Working Memory  

Microsoft Academic Search

In 5 experiments, the character of concurrent cognitive processing was manipulated during an event-based prospective memory task. High- and low-load conditions that differed only in the difficulty of the concurrent task were tested in each experiment. In Experiments 1 and 2, attention-demanding tasks from the literature on executive control produced decrements in prospective memory. In Experiment 3, attention was divided

Richard L. Marsh; Jason L. Hicks

1998-01-01

101

Event-based prospective memory and executive control of working memory  

Microsoft Academic Search

In 5 experiments, the character of concurrent cognitive processing was manipulated during an event-based prospective memory task. High- and low-load conditions that differed only in the difficulty of the concurrent task were tested in each experiment. In Experiments 1 and 2, attention-demanding tasks from the literature on executive control produced decrements in prospective memory. In Experiment 3, attention was divided

Richard L. Marsh; Jason L. Hicks

1998-01-01

102

A load-balancing readout method for large event-based PWM imaging arrays  

Microsoft Academic Search

This paper describes concept and implementation of an asynchronous, column-parallel readout method for event-based pulse-width-modulation (PWM) image sensors. These time-based imaging devices transmit exposure information in the form of asynchronous spike-events (AER) via an arbitrated asynchronous data bus that is common to all pixels. Event-collisions on the bus distort the time information and lead to errors in the instantaneous illumination

Daniel Matolin; Rainer Wohlgenannt; Martin Litzenberger; Christoph Posch

2010-01-01

103

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

NASA Astrophysics Data System (ADS)

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.

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

2009-04-01

104

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

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

105

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

SciTech Connect

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.

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

106

Event-based Plausibility Immediately Influences On-line Language Comprehension  

PubMed Central

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

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

2011-01-01

107

Valenced Cues and Contexts Have Different Effects on Event-Based Prospective Memory  

PubMed Central

This study examined the separate influence and joint influences on event-based prospective memory task performance due to the valence of cues and the valence of contexts. We manipulated the valence of cues and contexts with pictures from the International Affective Picture System. The participants, undergraduate students, showed higher performance when neutral compared to valenced pictures were used for cueing prospective memory. In addition, neutral pictures were more effective as cues when they occurred in a valenced context than in the context of neutral pictures, but the effectiveness of valenced cues did not vary across contexts that differed in valence. The finding of an interaction between cue and context valence indicates that their respective influence on event-based prospective memory task performance cannot be understood in isolation from each other. Our findings are not consistent with by the prevailing view which holds that the scope of attention is broadened and narrowed, respectively, by positively and negatively valenced stimuli. Instead, our findings are more supportive of the recent proposal that the scope of attention is determined by the motivational intensity associated with valenced stimuli. Consistent with this proposal, we speculate that the motivational intensity associated with different retrieval cues determines the scope of attention, that contexts with different valence values determine participants’ task engagement, and that prospective memory task performance is determined jointly by attention scope and task engagement. PMID:25647484

Graf, Peter; Yu, Martin

2015-01-01

108

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

| 541-346-5020 | gcr@uoregon.edu | 12/12/12 | p.2 4. Management and control of property on fulfilling the University's public mission Critical statutory authorities needed Broad authority to manage tuition. As a public university, the UO is committed to providing access for Oregon residents. Tuition

Oregon, University of

109

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)

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.

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.

110

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

NASA Astrophysics Data System (ADS)

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

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

2007-12-01

111

Models and Monte Carlo simulations of GCR and SPE organ doses with different shielding, based on the FLUKA code coupled with anthropomorphic phantoms  

NASA Astrophysics Data System (ADS)

Astronauts' exposure to space radiation is of major concern for long-term missions, especially for those in deep space such as a possible mission to Mars. Shielding optimization is therefore a crucial issue, and simulations based on radiation transport codes coupled with anthropomorphic model phantoms can be of great help. In this work, carried out with the FLUKA MC code and two anthropomorphic phantoms (a mathematical model and a "voxel" model), distributions of physical (i.e. absorbed), equivalent and "biological" dose in the various tissues and organs were calculated in different shielding conditions for solar minimum and solar maximum GCR spectra, as well as for the August 1972 Solar Particle Event. The biological dose was modeled as the average number of "Complex Lesions" (CL) per cell in a given organ. CLs are clustered DNA breaks previously calculated with "event-by-event" track structure simulations and integrated in the condensed-history FLUKA code. This approach is peculiar in that it is an example of a mechanistically-based quantification of the ionizing radiation action in biological targets; indeed CLs have been shown to play a fundamental role in chromosome aberration induction. The contributions of primary particles and secondary hadrons were calculated separately, thus allowing quantification of the role of nuclear reactions in the shield and in the human body. As expected, the doses calculated for the 1972 SPE decrease dramatically with increasing the Al shielding; nuclear reactions were found to be of minor importance, although their role is higher for internal organs and large shielding. An Al shield thickness of 10 g/cm2 appears sufficient to respect the 30-day deterministic limits recommended by NCRP for missions in Low Earth Orbit. In contrast with the results obtained for SPE, GCR doses to internal organs are not significantly lower than skin doses. However, the relative contribution of secondary hadrons was found to be more important for internal organs due to nuclear interactions in the human body. Both for skin and for internal organs, the physical dose was found to be essentially independent of the shield thickness. The equivalent and biological doses to skin show a significant decrease starting from 5 g/cm2, whereas internal organs show more complex trends characterized by minima and maxima mainly dependent on the organ type. Polyethylene shielding resulted to be more effective with respect to Aluminum.

Ballarini, F.; Fluka-Phantoms Team

112

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

NASA Astrophysics Data System (ADS)

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

Gaál, L.; Molnar, P.; Szolgay, J.

2014-05-01

113

ASYNCAR, a Radio-Controlled Vehicle for Asynchronous Experiments Implementation of an Event-Based Cruise Control  

E-print Network

-Based Cruise Control Sylvain Durand1,2,3, Julien Minet3,4, Jose Fermi Guerrero Castellanos5, Nicolas Marchand3 to reduce the computational cost. In this paper, we propose to firstly test an asynchronous cruise control, asynchronous cruise con- trol, event-based control INTRODUCTION The classical so-called discrete time framework

Boyer, Edmond

114

Improved isolation of the p-p underlying event based on minimum-bias trigger-associated hadron correlations  

E-print Network

Improved isolation of the p-p underlying event based on minimum-bias trigger-associated hadron aspects of hadron production in p-p collisions remain unresolved, including the low-hadron for hadron production in p-p collisions relate to dijet production, both the frequency of hard parton

Heller, Barbara

115

Monetary incentive effects on event-based prospective memory three months after traumatic brain injury in children  

Microsoft Academic Search

Information regarding the remediation of event-based prospective memory (EB-PM) impairments following pediatric traumatic brain injury (TBI) is scarce. Addressing this, two levels of monetary incentives were used to improve EB-PM in children ages 7 to 16 years with orthopedic injuries (OI, n = 51), or moderate (n = 25) and severe (n = 39) TBI at approximately 3 months postinjury.

Stephen R. McCauley; Claudia Pedroza; Sandra B. Chapman; Lori G. Cook; Ana C. Vásquez; Harvey S. Levin

2011-01-01

116

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

E-print Network

makes use of a fixed displacement pump, a pressure regulating relief valve and a throttling valveEvent 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

Li, Perry Y.

117

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

Microsoft Academic Search

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,

Franklin Dexter; Ruth E Wachtel; Richard H Epstein

2011-01-01

118

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

ERIC Educational Resources Information Center

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

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

2011-01-01

119

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

E-print Network

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

Boyer, Edmond

120

The 32 bit timing unit of a real-time event-based control system for a nuclear fusion experiment  

Microsoft Academic Search

This paper describes the innovative timing unit of a distributed, expandable, real-time, event-based control system for a nuclear fusion experiment. This system is being designed in a tree-type topology, based in VME and CAMAC format modules that produce the timing signals required for the safe operation of the experiment diagnostics and digitizers. It also performs the broadcasting, processing and recording

J. Sousa; A. Combo; A. Batista; C. Correia; C. A. F. Varandas; D. Trotman; J. Waterhouse

1998-01-01

121

On the significance of the Nash-Sutcliffe efficiency measure for event-based flood models  

NASA Astrophysics Data System (ADS)

When modelling flood events, the important challenge that awaits the modeller is first to choose a rainfall-runoff model, then to calibrate a set of parameters that can accurately simulate a number of flood events and related hydrograph shapes, and finally to evaluate the model performance separately on each event using multi-criteria functions. This study analyses the significance of the Nash-Sutcliffe efficiency (NSE) and proposes a new method to assess the performance of flood event models (see Moussa, 2010, "When monstrosity can be beautiful while normality can be ugly : assessing the performance of event-based-flood-models", Hydrological Science Journal, in press). We focus on the specific cases of events difficult to model and characterized by low NSE values, which we call "monsters". The properties of the NSE were analysed as a function of the calculated hydrograph shape and of the benchmark reference model. As application case, a multi-criteria analysis method to assess the model performance on each event is proposed and applied on the Gardon d'Anduze catchment. This paper discusses first the significance of the well-known Nash-Sutcliffe efficiency (NSE) criteria function when calculated separately on flood events. The NSE is a convenient and normalized measure of model performance, but does not provide a reliable basis for comparing the results of different case studies. We show that simulated hydrographs with low or negative values of NSE, called "monsters", can be due solely to a simple lag translation or a homothetic ratio of the observed hydrograph which reproduces the dynamic of the hydrograph, with acceptable errors on other criteria. In the opposite, results show that simulations with a NSE close to 1 can become "monsters" and give very low values (even negative) of the criteria function G, if the average observed discharged used as a benchmark reference model in the NSE is modified. This paper argues that the definition of an appropriate benchmark for model performance, and in particular for measures such as the NSE values should become part of the "best practices" in hydrologic modelling. Every modelling study should justify the choice of an appropriate benchmark which will be necessarily different for different types of case studies depending on the main hydrological processes and the driving variables. The benchmark should be simple such as that every hydrologist can understand its explanatory power and, therefore, appreciate how much better the actual hydrologic model is. Then, on the basis of the previous results, we propose a new simple quick-to-use method to analyse the model performance using multi-criteria functions. In addition to the classical criteria functions, we define new complementary criteria functions, derived from the NSE on the basis of a lag translation (NSET) or a homothetic ratio (NSEH) of the calculated hydrograph. Using the NSET and NSEH, the modeller can see whether the shape of an event is well simulated but not the timing or the volume. We call "normal" the events for which all NSE, NSET and NSEH are high. We call "pseudo-monster" the events for which NSET and NSEH are high while NSE is low; hence, modelling these events can be improved when modifying the production or/and the transfer function. The remaining events for which NSE, NSET, NSEH and the remaining classical criteria functions are low are called "real monsters". This approach enables a correct diagnostic of the model failures and will guide the modeller in searching a solution to improve the simulations of the "pseudo monsters" : review the quality of the input data, modify the concepts of the model, modify the performance criteria functions, etc. However, modelling the "real monsters" remains unresolved, and model parameterisation, calibration, validation and evaluation is still a difficult issue for hydrological modelling.

Moussa, Roger

2010-05-01

122

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

PubMed

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

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

2014-10-01

123

Incentive Effects on Event-Based Prospective Memory Performance in Children and Adolescents with Traumatic Brain Injury  

PubMed Central

Prospective memory (PM) is the formation of an intention and remembering to perform this intention at a future time or in response to specific cues. PM tasks are a ubiquitous part of daily life. Currently, there is a paucity of information regarding PM impairments in children with traumatic brain injury (TBI) and less empirical evidence regarding effective remediation strategies to mitigate these impairments. The present study employed two levels of a motivational enhancement (i.e., a monetary incentive) to determine if event-based PM could be improved in children with severe TBI. In a cross-over design, children with orthopedic injuries and mild or severe TBI were compared on two levels of incentive (dollars versus pennies) given in response to accurate performance. All three groups performed significantly better under the high- versus low-motivation conditions. However, the severe TBI group’s high-motivation condition performance remained significantly below the low-motivation condition performance of the orthopedic injury group. PM scores were positively and significantly related to age-attest, but there were no age-at-injury or time-postinjury effects. Overall, these results suggest that event-based PM can be significantly improved in children with severe TBI. PMID:19254093

McCauley, Stephen R.; McDaniel, Mark A.; Pedroza, Claudia; Chapman, Sandra B.; Levin, Harvey S.

2011-01-01

124

Concentration of electrostatic solitary waves around magnetic nulls within magnetic reconnection diffusion region: single-event-based statistics  

NASA Astrophysics Data System (ADS)

It is important to study the `concentrated' electrostatic solitary waves/structures (ESWs) associated with the magnetic reconnection. In the literature published as regards this topic, very few studies have reported the observation of such a large number of ESWs in a single magnetic reconnection event. In this work, we report our observation of a large number of ESWs around the magnetic null-pairs within the magnetic reconnection ion diffusion region of Earth's magnetosphere on 10 September 2001. With more than 9,600 cases of ESWs observed around magnetic null-pairs and more than 97,600 cases observed during the ion diffusion region crossing time span, the observation of such a large number of ESWs in the diffusion region has not been reported often in published works. We further perform single-event-based statistical analysis of the characteristics of the ESWs around magnetic null-pairs. Based on the statistical result, we speculate that the two-stream instability originating from the magnetic null and traveling outward along the plasma sheet boundary layer (PSBL) is the candidate mechanism of the large number of observed ESWs. Our observation and analysis in this work suggests that even with the presence of a complex magnetic structure around a magnetic null-pair in the three-dimensional regime, concentrated ESWs can be observed. This single-reconnection-event-based statistical result of ESWs around the magnetic null-pairs can aid in understanding the microdynamics associated with three-dimensional (3D) magnetic reconnection.

Li, Shiyou; Zhang, Shifeng; Cai, Hong; Yu, Sufang

2014-12-01

125

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

PubMed Central

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

2011-01-01

126

Monetary Incentive Effects on Event-Based Prospective Memory Three Months after Traumatic Brain Injury in Children  

PubMed Central

Information regarding the remediation of event-based prospective memory (EB-PM) impairments following pediatric traumatic brain injury (TBI) is scarce. Addressing this, two levels of monetary incentives were used to improve EB-PM in children ages 7 to 16 years with orthopedic injuries (OI, n = 51), or moderate (n = 25), and severe (n = 39) TBI at approximately three months postinjury. The EB-PM task consisted of the child giving a specific verbal response to a verbal cue from the examiner while performing a battery of neuropsychological measures (ongoing task). Significant effects were found for Age-at-Test, Motivation Condition, Period, and Group. Within-group analyses indicated OI and moderate TBI groups performed significantly better under the high-versus low-incentive condition, but the severe TBI group demonstrated no significant improvement. These results indicate EB-PM can be significantly improved at three months postinjury in children with moderate, but not severe, TBI. PMID:21347945

Pedroza, Claudia; Chapman, Sandra B.; Cook, Lori G.; Vásquez, Ana C.; Levin, Harvey S.

2011-01-01

127

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

PubMed

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

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

2013-10-30

128

Event-Based Characterization of Hydrologic Change in Urbanizing Southern Ontario Watersheds via High Resolution Stream Gauge Data  

NASA Astrophysics Data System (ADS)

Tracking and quantifying hydrologic change in urban watersheds is a complex problem; land use and permeability can vary not only spatially throughout the effective catchment area but also temporally as change occurs. Hydromodification due to urbanization usually results in a larger peak event stream discharge, a change in typical event volume, a reduced lag time between rainfall and stream discharge events, and a more complex falling hydrograph. Recently extracted Environment Canada data have allowed the creation of a high resolution instantaneous stream flow dataset dating to the late 1960s for many Ontario gauge stations. Hydrometric data were obtained for fifteen urban and semi-urban catchments within Southern Ontario ranging in size from ~50km2 to 300 km2 with an urbanized land area varying from <5% to 80%. Utilizing automated methods, each individual runoff event from the hydrographic record was identified and characterized; event parameters such as peak discharge, duration, volume, and flashiness were calculated. Temporal changes to urban land area, permeability, land use, and road length were quantified for each watershed from aerial photography spanning the period of record at approximately 8 year intervals. This allows for the identified trends in event hydrograph parameters to be correlated quantitatively with the alteration of the catchment over time. In addition, event-based hydrograph separation methodologies were developed to track subtle changes to groundwater infiltration and interflow over time. Changes to flood return intervals through the period of urbanization were also investigated and compared to catchment permeability.

Thompson, P. J.; Annable, W. K.

2011-12-01

129

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

PubMed

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

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

2014-01-01

130

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

ERIC Educational Resources Information Center

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

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

2010-01-01

131

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

E-print Network

systems and the move to a digital infrastructure has transformed surveillance into a large scale data data, perform event based retrieval, receive real time event alerts thru standard web infrastructure in an airport is "cars that stop in the loading zone for extended periods of time." As smart surveillance

Senior, Andrew

132

A Framework for Event-Based Software Integration Daniel J. Barrett, Lori A. Clarke, Peri L. Tarr, and Alexander E. Wise  

E-print Network

A Framework for Event-Based Software Integration Daniel J. Barrett, Lori A. Clarke, Peri L. Tarr F30602-94-C-0137. Name: Daniel J. Barrett Address: barrett@cs.umass.edu Name: Lori A. Clarke Address. Abstracting with credit is permitted. To copy otherwise, to republish, to post on servers, to redistribute

Massachusetts at Amherst, University of

133

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

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…

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

2013-01-01

134

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

PubMed Central

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

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

2012-01-01

135

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

PubMed

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

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

2015-01-01

136

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

NASA Astrophysics Data System (ADS)

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

Leroux, J.; Lague, D.

2012-12-01

137

Modeling of GCR Environment Variations and Interpretation for Human Explorations  

Microsoft Academic Search

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

Premkumar Saganti

2010-01-01

138

GCR-Induced Photon Luminescence of the Moon  

NASA Technical Reports Server (NTRS)

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].

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

2008-01-01

139

Distributed Architectures for Event-Based Systems  

Microsoft Academic Search

\\u000a Event-driven distributed systems have two important characteristics, which differentiate them from other system types: the\\u000a existence of several software or hardware components that run simultaneously on different inter-networked nodes, and the use\\u000a of events as the main vehicle to organize component intercommunication. Clearly, both attributes influence event-driven distributed\\u000a architectures, which are discussed in this chapter. We start with presenting the

Valentin Cristea; Florin Pop; Ciprian Dobre; Alexandru Costan

140

Event-based modeling and processing of digital media  

Microsoft Academic Search

Capture, processing, and assimilation of digital media-based information such as video, images, or audio requires a unified framework within which signal processing techniques and data modeling and retrieval approaches can act and interact. In this paper we present the rudiments of such a framework based on the notion of \\

Rahul Singh; Zhao Li; Pilho Kim; Derik Pack; Ramesh Jain

2004-01-01

141

A Bayesian Model for Event-based Trust  

Microsoft Academic Search

The application scenarios envisioned for 'global ubiquitous computing ' have unique re- quirements that are often incompatible with traditional security paradigms. One alternative currently being investigated is to support security decision-making by explicit representa- tion of principals' trusting relationships, i.e., via systems for computational trust. We focus here on systems where trust in a computational entity is interpreted as the

Mogens Nielsen; Karl Krukow; Vladimiro Sassone

2007-01-01

142

Automating performance-related impact analysis through event based traceability  

Microsoft Academic Search

Current impact analysis techniques tend to focus on assessing the impact of change upon the system's functionality, whilst a consideration of performance related requirements is often deferred until after implementation. This tendency can lead to costly and time-consuming mistakes that frustrate customers and require frantic last-minute efforts to fix. This paper proposes a method for supporting performance-related impact analysis in

Jane Cleland-huang; Carl K. Chang; Jeffrey C. Wise

2003-01-01

143

Event-based runtime verification of java programs  

Microsoft Academic Search

We introduce the temporal logic HAWK and its supporting tool for runtime verification of Java programs. A monitor for a HAWK formula checks if a finite trace of program events satisfies the formula. HAWK is a programming-oriented extension of the rule-based EAGLE logic that has been shown capable of defining and implementing a range of finite trace monitoring logics, including

Marcelo d'Amorim; Klaus Havelund

2005-01-01

144

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

NASA Technical Reports Server (NTRS)

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.

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

2013-01-01

145

Event-Based Soccer Video Retrieval with Interactive Genetic Algorithm  

Microsoft Academic Search

This paper proposes an interactive genetic algorithm (IGA) for soccer video events retrieval with multimodal features. Eight audio-visual features (average shot duration, standard deviation of shot duration, average motion activity, standard deviation of motion activity, average sound energy, standard deviation of sound energy, average speech rate and standard deviation of speech rate) were extracted from each video in database. Then

Guangsheng Zhao

2008-01-01

146

INVITED SESSION NUMBER: 157 Event-Based Feedback Control  

E-print Network

potentials [11],[4]. Such disorders may be treated by a surgically implanted device, similar to a cardiac pacemaker, that sends a high frequency elec- trical stimulus into the motor control region of the brain-compulsive disorder, and even depression [1]. Since its approval by the FDA in 1997 for use in advanced cases of PD

Moehlis, Jeff

147

Visual tracking using neuromorphic asynchronous event-based cameras.  

PubMed

This letter presents a novel computationally efficient and robust pattern tracking method based on a time-encoded, frame-free visual data. Recent interdisciplinary developments, combining inputs from engineering and biology, have yielded a novel type of camera that encodes visual information into a continuous stream of asynchronous, temporal events. These events encode temporal contrast and intensity locally in space and time. We show that the sparse yet accurately timed information is well suited as a computational input for object tracking. In this letter, visual data processing is performed for each incoming event at the time it arrives. The method provides a continuous and iterative estimation of the geometric transformation between the model and the events representing the tracked object. It can handle isometry, similarities, and affine distortions and allows for unprecedented real-time performance at equivalent frame rates in the kilohertz range on a standard PC. Furthermore, by using the dimension of time that is currently underexploited by most artificial vision systems, the method we present is able to solve ambiguous cases of object occlusions that classical frame-based techniques handle poorly. PMID:25710087

Ni, Zhenjiang; Ieng, Sio-Hoi; Posch, Christoph; Régnier, Stéphane; Benosman, Ryad

2015-04-01

148

Event-based Simulation Model for Quantum Optics Experiments  

E-print Network

. With Einstein's explanation of the photoelectric effect in terms of photons, that is in terms of indivisible quanta gave birth to the quantum description of light. As the photoelectric effect can be explained by treating the electromagnetic field without assuming the existence of photons [3], the photoelectric effect

149

Event-based data dissemination control in healthcare  

E-print Network

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

Cambridge, University of

150

Event-based Service Coordination Gianluigi Ferrari1  

E-print Network

-56127, Pisa, Italy {giangi,strollo}@di.unipi.it 2 Institute for Advanced Studies IMT Lucca Piazza S. Ponziano 6, 55100, Lucca, Italy {roberto.guanciale,daniele.strollo}@imtlucca.it 3 University of Leicester

Tuosto, Emilio

151

"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

152

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

SciTech Connect

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.

NONE

1995-05-31

153

at a rate of 4.8 protons cm 2 --that is, the GCR  

E-print Network

a typical solar cycle. The production rate of 59 Ni was calculat- ed by integration over the energy-NCS-44945 (ENDF-102) (Brookhaven National Laboratory, Upton, NY 1995). 24. J. Klein et al., Lunar Planet

Davis, James C.

154

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

SciTech Connect

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.

NONE

1995-03-31

155

Conduction Velocity of the Uterine Contraction in Serial Magnetomyogram (MMG) Data: Event Based Simulation and Validation  

PubMed Central

We propose a novel approach to calculate the conduction velocity (CV) of the uterine contraction bursts in magnetomyogram (MMG) signals measured using a multichannel SQUID array. For this purpose, we partition the sensor coordinates into four different quadrants and identify the contractile bursts using a previously proposed Hilbert-wavelet transform approach. If contractile burst is identified in more than one quadrant, we calculate the center of gravity (CoG) in each quadrant for each time point as the sum of the product of the sensor coordinates with the Hilbert amplitude of the MMG signals normalized by the sum of the Hilbert amplitude of the signals over all sensors. Following this we compute the delay between the CoGs of all (six) possible quadrant pairs combinations. As a first step, we validate this approach by simulating a stochastic model based on independent second-order autoregressive processes (AR2) and we divide them into 30 second disjoint windows and insert burst activity at specific time instances in preselected sensors. Also we introduce a lag of 5 ± 1 seconds between different quadrants. Using our approach we calculate the CoG of the signals in a quadrant. To this end, we compute the delay between CoGs obtained from different quadrants and show that our approach is able to reliably capture the delay incorporated in the model. We apply the proposed approach to 19 serial MMG data obtained from two subjects and show an increase in the CV as the subjects approached labor. PMID:22255713

Preissl, Hubert; Lowery, Curtis L.; Eswaran, Hari; Govindan, Rathinaswamy B.

2012-01-01

156

Event-based approach to money laundering data analysis and visualization  

Microsoft Academic Search

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

Tat-Man Cheong; Yain-Whar Si

2010-01-01

157

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

NASA Astrophysics Data System (ADS)

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.

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

2015-02-01

158

Prediction of consequences of meteor events based on atmospheric trajectory analysis  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

159

Event-Based Modeling of Driver Yielding Behavior at Unsignalized Crosswalks  

PubMed Central

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

Schroeder, Bastian J.; Rouphail, Nagui M.

2011-01-01

160

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

Microsoft Academic Search

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

ISABEL SANMARTÍN; FREDRIK RONQUIST

2004-01-01

161

Department of Computing Combining event-based and state-based  

E-print Network

with the formal modelling of sig- nalling and point control in the domain of railway engineering. Rules counter example traces if verification fails. 1 Introduction Formal verification of railway control-based and state-based modeling for railway verification Faron Moller Hoang Nga Nguyen Markus Roggenbach Steve

Doran, Simon J.

162

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

PubMed

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

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

2013-01-01

163

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

PubMed Central

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

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

2013-01-01

164

Uncovering continuous and transient monitoring profiles in event-based prospective memory.  

PubMed

The present study implemented response time distribution modeling to better characterize context-specific attention dynamics underlying task interference due to possessing a prospective memory intention. During a three-phase paradigm in which prospective memory cues appeared only in the final phase, prospective memory performance was better when participants were informed at encoding of the context in which cues were to appear than when participants were not informed. Additionally, task interference increased during the third phase when the cue context was previously specified. Ex-Gaussian parameter estimates revealed that task interference during the third phase was due to a greater relative frequency of longer latencies, rather than an overall increase in latencies across all trials, suggesting that participants relied primarily on transient, rather than continuous, monitoring processes to support cue detection. Functionally, variability in transient and continuous monitoring profiles was predictive of prospective memory cue detection. More generally, the results from the present study suggest that ex-Gaussian parameter estimation procedures may provide a fruitful avenue for better understanding how attention is differentially allocated to ongoing tasks, what processes might underlie monitoring behavior, and how this behavior is related to eventual intention fulfillment. PMID:25100232

Ball, B Hunter; Brewer, Gene A; Loft, Shayne; Bowden, Vanessa

2015-04-01

165

An Event Based Framework for Improving Information Quality That Integrates Baseline Models, Causal Models  

E-print Network

Models and Formal Reference Models Joseph Bugajski Visa International PO Box 8999 San Francisco, CA is the real time analysis of traffic pat- terns over a metropolitan region in order to quickly identify

Grossman, Robert

166

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

Microsoft Academic Search

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

O. Luc

2007-01-01

167

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

PubMed Central

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.

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

168

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

E-print Network

, bi- ological, radiological, nuclear, and combinations of these. These WMD types differ and communications, recruitment, weapons procure- ment, logistics, surveillance, operations, and finance to the various specific tasks outlined above, generally con- tributes to the likelihood of a successful, high

Ritter, Frank

169

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

E-print Network

University of Technology Department of Information and Computer Science, Aalto University ABSTRACT Sound and understand the human and social activities. Automatic sound event detection aims at processing a continuous, having multiple overlapping sound events active at the same time. If an algorithm that detects only

Virtanen, Tuomas

170

Dynamic Event-Based Runtime Monitoring of Real-Time and Contextual Properties  

E-print Network

for the runtime monitoring of a real life case study -- an online transaction system for credit card. The features- timate holy grail of providing a guarantee of the absence of errors from a given system. Though testing. We present dynamic communicating au- tomata with timers and events to describe properties of systems

Pace, Gordon J.

171

Event-Based Input Validation Using Design-by-Contract Patterns  

Microsoft Academic Search

This paper proposes an approach for validation of numerical inputs based on graphical user interfaces (GUI) that are modeled and specified by event sequence graphs (ESG). For considering complex structures of input data, ESGs are augmented by decision tables and patterns of design by contract (DbC). The approach is evaluated by experiments on boundary overflows, which occur when input values

Tugkan Tuglular; Can Arda Muftuoglu; Fevzi Belli; Michael Linschulte

2009-01-01

172

Earthquake source inversion for moderate magnitude seismic events based on GPS simulated high-rate data  

NASA Astrophysics Data System (ADS)

The development of GNSS technology with the potential of high-rate (up to 100Hz) GNSS (GPS, GLONASS, Galileo, Compass) records allows the monitoring of the seismic ground motions. In this study we show the potential of estimating the earthquake magnitude (Mw) and the fault geometry parameters (slip, depth, length, rake, dip, strike) during the propagation of seismic waves based on high-rate GPS network data and using a non-linear inversion algorithm. The examined area is the Valais (South-West Switzerland) where a permanent GPS network of 15 stations (COGEAR and AGNES GPS networks) is operational and where the occurrence of an earthquake of Mw?6 is possible every 80 years. We test our methodology using synthetic events of magnitude 6.0-6.5 corresponding to normal fault according to most of the fault mechanisms of the area, for surface and buried rupture. The epicentres are located in the Valais close to the epicentre of previous historical earthquakes. For each earthquake, synthetic seismic data (velocity records) of 15 sites, corresponding to the current GPS network sites in Valais, were produced. The synthetic seismic data were integrated into displacement time-series. By jointly using these time-series with the Bernese GNSS Software 5.1 (modified), 10Hz sampling rate GPS records were generated assuming a noise of peak-to-peak amplitudes of ±1cm and ±3cm for the horizontal and for the vertical components, respectively. The GPS records were processed and resulted in kinematic time series from where the seismic displacements were derived and inverted for the magnitude and the fault geometry parameters. The inversion results indicate that it is possible to estimate both, the earthquake magnitudes and the fault geometry parameters in real-time (~10 seconds after the fault rupture). The accuracy of the results depends on the geometry of the GPS network and of the position of the earthquake epicentre.

Psimoulis, Panos; Dalguer, Luis; Houlie, Nicolas; Zhang, Youbing; Clinton, John; Rothacher, Markus; Giardini, Domenico

2013-04-01

173

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

E-print Network

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 ...

Rabbani, Fábio Faizi Rahnemay, 1978-

2004-01-01

174

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

PubMed Central

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

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

2013-01-01

175

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

PubMed

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

Schroeder, Bastian J; Rouphail, Nagui M

2011-07-01

176

Rainfall–runoff response and event-based runoff coefficients in a humid area (northwest Spain)  

Microsoft Academic Search

The hydrological response of a small agroforestry catchment in northwest Spain (Corbeira catchment, 16 km) is analysed, with particular focus on rainfall events. Fifty-four rainfall–runoff events, from December 2004 to September 2007, were used to analyse the principal hydrological patterns and show which factors best explain the hydrological response. The nonlinearity between rainfall and runoff showed that the variability in

M. L. Rodríguez-Blanco; M. M. Taboada-Castro; M. T. Taboada-Castro

2012-01-01

177

Climate-Induced Shifts in Extreme Precipitation Events Based on Resolved Atmospheric Changes  

Microsoft Academic Search

Possible changes in patterns, intensity and frequency of extreme precipitation are among the primary hazardous impacts of climate change, and are also at the forefront of scientific and societal concern. Yet climate-model simulations in general do not resolve moist processes well, and further, cannot be relied upon for their representation of extreme events. However, these models do resolve large-scale (hemispheric)

C. A. Schlosser; X. Gao; M. Weber; D. Entekhabi

2010-01-01

178

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

NASA Astrophysics Data System (ADS)

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.

Shapoval, A.

2010-11-01

179

A Mobile Robots Experimental Environment with Event-Based Wireless Communication  

PubMed Central

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

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

2013-01-01

180

Correcting Parameters of Events Based on the Entropy of Microlensing Ensemble  

E-print Network

We entertain the idea that robust theoretical expectations can become a tool in removing hidden observational or data-reduction biases. We illustrate this approach for a specific problem associated with gravitational microlensing. Using the fact that a group is more than just a collection of individuals, we derive formulae for correcting the distribution of the dimensionless impact parameters of events, u_min. We refer to the case when undetected biases in the u_min distribution can be alleviated by multiplication of impact parameters of all events by a common constant factor. We show that in this case the general maximum likelihood problem of solving an infinite number of equations reduces to two constraints, and we find an analytic solution. Under the above assumptions, this solution represents a state in which the ``entropy'' of a microlensing ensemble is at its maximum, that is, the distribution of u_min resembles a specific, theoretically expected, box-like distribution to the highest possible extent. We also show that this technique does not allow one to correct the parameters of individual events on the event by event basis independently from each other.

Piotr Popowski; Charles Alcock

2002-02-21

181

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

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

182

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

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

183

An event based formal specification method to diabetic's behavior monitor system  

Microsoft Academic Search

Modern medical monitor systems shoulder the responsibility of patients’ surveillance. Such life-critical systems steering by software will put patient’s life in peril if they try in vain to satisfy patient’s requirements. As a prelude to reliable software construction of such systems, formal specification of the software behavior has been noted as an effective method because it is susceptible of formal

S. M. Babamir; M. Borhani Dehkordi

2011-01-01

184

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

PubMed Central

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

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

2014-01-01

185

Event based analysis of Chlorothalonil concentrations following application to managed turf  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

186

Securing harbor by combining probabilistic approach with event-based approach Salma Zouaoui-Elloumi  

E-print Network

As a part of SECuring MARitime (SECMAR) project that aimed to improve security at Marseilles harbor, we, it is worth paying a particular attention to the maritime space, which can be exposed to signicant risks to strengthen the overall supply chain and U.S. border security. · The Seveso directive of 1996: a European law

Boyer, Edmond

187

Hydrologic characterization using event based ?18O, Si, and hydrometric measurements  

NASA Astrophysics Data System (ADS)

Stable isotopes (i.e. ?18O and ?D) have been mainly used for defining sources of water in catchment studies. Studies on isotope exchange in soil water and hydrological flow paths during storm events are needed to complement hydrologic characterization of dominant hydrologic processes. We present preliminary results of the combination of hydrometric measurements, chemical tracers, and isotope hydrograph separation (IHS) that provide new insights into the role that geological characteristics and soil properties play during hydrological episodes such as spring snowmelt and rainfall events. Stream water, rainfall, snow melt, soil and shallow groundwater were analyzed for ?18O and ?D as well as silica using Wavelength-Scanned Cavity Ring Down Spectroscopy (WS-CRS) and spectrometric analysis, respectively. Geologic characterization and soil water content were recorded using Electrical Resistivity Tomography (ERT). Our findings will be related to hydrologic model parameterization.

Sanchez-Murillo, R.; Boll, J.; Brooks, E.

2009-12-01

188

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

ERIC Educational Resources Information Center

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…

Bondos, Sarah E.; Phillips, Dereth

2008-01-01

189

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

NASA Astrophysics Data System (ADS)

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.

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

190

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

Microsoft Academic Search

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

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

2008-01-01

191

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

E-print Network

for extracting structured information from biological bibliographical databases, especially Medline. The paper species (e.g. Flybase, specialized on Drosophilia Menogaster) or not (e.g. Medline). This type (LIPN, INRA and Leibniz- IMAG) and NLP teams (LIPN) as major partners, plus LRI and INRIA from 2000

Paris-Sud XI, Université de

192

Event-based integration using on-the-fly matching Anders Moen Hagalisletto  

E-print Network

(CARDX) msg GETCARD msg GETCARD A wildcard(DECK) from DEAL to A from DEAL to A msg DONE msg refresh from DEAL to A msg JOINGAME from A to DEAL msg WIN A wildcard(VALUE) from DEAL to A msg REQUESTCARD from DEAL to A from A to DEAL start from DEAL to A msg LOOSE A play evaluate dealerplay2stand dealerplay submit

Tucci, Sara

193

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

PubMed

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

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

2005-01-01

194

Admission Control for Wireless Networks with Heterogeneous Traffic using Event Based Resource Estimation  

Microsoft Academic Search

In this paper a new distributed adaptive admission control algorithm for wireless cellular networks with heterogeneous traffic is proposed. The resources needed for handoff calls are estimated by calculating the probability of visiting particular cells during the call lifetime based on the call duration and residence time statistics. This information is then communicated to the base stations in the S

Jelena V. Misic; Samuel T. Chanson; Frederick S. Lai

1997-01-01

195

Event based resource estimation in admission control for wireless networks with heterogeneous traffic  

Microsoft Academic Search

A technique for estimating the resources needed to maintain an upper bound on handoff dropping probability in wireless networks with heterogeneous traffic is presented. The calculation is based on the number and characteristics of connections in the surrounding cells. The information is collected from the base stations in the S surrounding rings and is updated at handoff and call termination

Jelena Miši?; Samuel T. Chanson; Frederick S. Lai

1997-01-01

196

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

PubMed

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

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

1992-01-01

197

Event-Based Plausibility Immediately Influences On-Line Language Comprehension  

ERIC Educational Resources Information Center

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…

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

2011-01-01

198

An Event-based Platform for Collaborative Threats Detection and Monitoring  

E-print Network

from the same cyber crimes. Sharing and correlating information could help them in early detecting Aniello, Giuseppe A. Di Luna, Roberto Baldoni Cyber Intelligence and Information Security Research Centre those crimes and mitigating the damages. The paper discusses the Semantic Room (SR) abstraction which en

Tucci, Sara

199

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

PubMed

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

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

2011-09-01

200

Event-Based Monitoring of Open Source Software Projects Dindin Wahyudin, A Min Tjoa  

E-print Network

indicators of five OSS projects listed in the Apache Incubator. Keywords--Software Project Management, System) proposes the Incubator System2 for newly-added projects under its umbrella. ASF is mainly interested: 17/11/2006 2 http://incubator.apache.org/ developers; hence one of the Incubator's objectives

201

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

Microsoft Academic Search

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

Alejandro P. Buchmann

2007-01-01

202

Investigation of the Earth Ionosphere during extreme solar events based on two different observation methods  

NASA Astrophysics Data System (ADS)

The first approach is based on observations from ground stations to GNSS. Apart from global TEC maps also regional maps were determined and compared to those offered by different analysis centres within the IGS. Beside a solution based on smoothed code also one with double differenced carrier phase were calculated. The research covered not only the present quiet conditions but also periods of extreme solar events like the Halloween events in 2003. The other approach used accelerometer data from LEO like CHAMP and GRACE to calculate the thermospheric density in about 400km height. Results were compared with state of the art models like the Jacchia Bowman 2008.

Krauss, S.; Stangl, G.; Hausleitner, W.

2009-04-01

203

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

204

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

205

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

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

206

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

Code of Federal Regulations, 2010 CFR

... (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...

2010-01-01

207

Proposal for an Interference Experiment to Test the Applicability of Quantum Theory to Event-Based Processes  

NASA Astrophysics Data System (ADS)

We analyze a single-particle Mach--Zehnder interferometer experiment in which the path length of one arm may change (randomly or systematically) according to the value of an external two-valued variable x, for each passage of a particle through the interferometer. Quantum theory predicts an interference pattern that is independent of the sequence of the values of x. On the other hand, corpuscular models that reproduce the results of quantum optics experiments carried out to date show a reduced visibility and a shift of the interference pattern depending on the details of the sequence of the values of x. The proposed experiment will show that: (1) it can be described by quantum theory, and thus not by the current corpuscular models, or (2) it cannot be described by quantum theory but can be described by the corpuscular models or variations thereof, or (3) it can neither be described by quantum theory nor by corpuscular models. Therefore, the proposed experiment can be used to determine the extent to which quantum theory provides a description of observed events beyond the usual statistical level.

Michielsen, Kristel; Lippert, Thomas; Richter, Marcus; Barbara, Bernard; Miyashita, Seiji; Raedt, Hans De

2012-03-01

208

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

NASA Astrophysics Data System (ADS)

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.

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

2013-05-01

209

Survey of accidents in suburban Tehran and the prediction of future events based on a time-series model  

PubMed Central

Background: Car accidents are currently a social issue globally because they result in the deaths of many people. The aim of this study was to examine traffic accidents in suburban Tehran and forecast the number of future accidents using a time-series model. Methods: The sample population of this cross-sectional study was all traffic accidents that caused death and physical injuries in suburban Tehran in 2010 and 2011, as registered by the Tehran Emergency Section. In the present study, Minitab 15 software was used to provide a description of traffic accidents in suburban Tehran for the specified time period as well as those that occurred during April 2012. Results: The results indicated that the average number of traffic accidents in suburban Tehran per day in 2010 was 7.91 with a standard deviation of 7.70. This figure for 2011 was 6 daily traffic accidents with a standard deviation of 5.30. A one-way analysis of variance indicated that the average of traffic accidents in suburban Tehran was different for different months of the year (P = 0.000). The study results showed that different seasons in 2010 and 2011 had significantly different numbers of traffic accidents (P < 0.05). Through an auto-regressive moving average (ARMA), it was predicted that there would be 166 traffic accidents in April 2012 with a mean of 5.53 and maximum of 6 traffic accidents/day. Conclusion: There has been a decreasing trend in the average number of traffic accidents per day. PMID:25763141

Heidar Teymuri, Ghulam; Bahmani, Rahman; Asghari, Mehdi; Madrese, Elham; Rahmani, Abdolrasoul; Abbasinia, Marzieh; Ahmadnezhad, Iman; Samavati, Mehdi

2014-01-01

210

AdScorer: an event-based system for near real-time impact analysis of television advertisements (industry article)  

Microsoft Academic Search

The media measurement industry is in turmoil, with the old prediction-based models being challenged by more accurate measurement techniques, based on actual viewer behaviour drawn from much larger sample selections. As measurement methods converge across different types of media, the online\\/offline measurement divide will diminish. Television is one such medium that has traditionally required offline measurements. Advertisers are, for the

Pål Evensen; Hein Meling

2012-01-01

211

RCPSP with res. production and consumption Proposals Computational results Conclusions An On/Off Event-based formulation for the  

E-print Network

(parallel machines, flow-shops, job-shops, flexible shop problems...) 4/30 O. KONE, C. ARTIGUES, P. LOPEZ, M Definition RCPSP: Resource-Constrained Project Scheduling Problem Definition: Cumulative scheduling problem Multi-resources Many applications in industry Covers a large number of theoretical scheduling problems

Ingrand, François

212

RCPSP with res. production and consumption Proposals Computational results Conclusions Event-based formulations for the RCPSP with  

E-print Network

...) Covers a large number of theoretical scheduling problems (parallel machines, flow-shops, job-shops Conclusions Definition RCPSP: Resource-Constrained Project Scheduling Problem Definition: Cumulative scheduling problem Multi-resources Many applications in industry (staff scheduling, parallel processors

Ingrand, François

213

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

PubMed

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

Delbruck, Tobi; Lang, Manuel

2013-01-01

214

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

NASA Astrophysics Data System (ADS)

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

Xu, Kang; Su, Jingzhi; Zhu, Congwen

2014-07-01

215

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

PubMed

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

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

2013-01-01

216

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

PubMed Central

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

Delbruck, Tobi; Lang, Manuel

2013-01-01

217

A Semi-automatic Ontology Learning Based on WordNet and Event-based Natural Language Processing  

Microsoft Academic Search

Ontology is more and more popular in all kinds of knowledge management system, but the manual acquisition of ontologies still remains a tedious, cumbersome task. Meanwhile moving toward semi-automation or automation of ontology construction is a solution. In this paper, we proposed a semiautomatic ontology building approach. In this approach the system starts form a small core ontology constructed by

Wen Zhou; Zongtian Liu; Yan Zhao; Libin Xu; Guang Chen; Qiang Wu; Mei-li Huang; Yu Wen Qiang

2006-01-01

218

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

E-print Network

of the controlled system varies). Typical event-detection mechanisms are functions on the variation of the state (or). Among many embedded and networked cyber-physical systems, Unmanned Aerial Vehicles (UAVs) have received

Paris-Sud XI, Université de

219

Integration of a loop based and an event based framework for control of a bimanual dextrous service robot  

Microsoft Academic Search

Different components are needed to control a service robot, which helps people in the household environment to do daily tasks. Controllers in closed loop are needed to control the actuators and sensors to provide actions. A sequencer schedules and coordinates these actions to finish a given task. And an AI planner is also needed to generate the sequence of the

S. W. Ruhl; Zhixing Xue; J. M. Zollner; R. Dillmann

2009-01-01

220

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

Microsoft Academic Search

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

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

2009-01-01

221

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

PubMed

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

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

2015-04-01

222

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

PubMed

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

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

2005-01-01

223

Observer agreement for timed-event sequential data: A comparison of time-based and event-based algorithms  

Microsoft Academic Search

Observer agreement is often regarded as the sine qua non of observational research. Cohen’s ? ?is a widely used index and is appropriate when discrete entities—such as a turn-of-talk\\u000a or a demarcated time interval—are presented to pairs of observers to code. ?-like statistics and agreement matrices are also\\u000a used for the timed-event sequential data produced when observers first segment and

Roger Bakeman; Vicenç Quera; Augusto Gnisci

2009-01-01

224

Monitoring of event based mobilization of hydrophobic pollutants in rivers: Calibration of turbidity as a proxy for particle facilitated transport  

NASA Astrophysics Data System (ADS)

Transport of many pollutants in rivers is coupled to transport of suspended particles which is typically enhanced during events such as floods, snow melts etc. As the amount of total suspended solids (TSS) in rivers can be monitored by turbidity measurements this may be used as a proxy for the total concentration of particle associated pollutants in rivers such as polycyclic aromatic hydrocarbons (PAHs), PCBs, etc. and several heavy metals. On-line turbidity measurements (e.g. by optical backscattering sensors) then allow for an assessment of particle and pollutant flux dynamics. In this study, pronounced flood and thus turbidity events were sampled at high temporal resolution in three contrasting catchments in Southwest Germany (Rivers Ammer, Goldersbach, Steinlach) as well as in the River Neckar. Samples were analyzed for turbidity, the total amount of PAH and total suspended solids (TSS) in water. Additionally, the grain size distributions of suspended solids were determined. Discharge and turbidity were measured on-line at gauging stations in three of the catchments. Results showed that turbidity and TSS were linearly correlated over an extended turbidity range up to 2000 NTU for the flood samples (i.e. independent on grain size). This also holds for total PAH concentrations which can be reasonably well predicted based on the turbidity measurements and TSS versus PAH relationships - even for very high turbidity or TSS values (> 2000 NTU or mg l-1, respectively). From these linear regressions concentrations of PAHs on suspended particles were obtained which varied by catchment. The values comprise a robust measure of the average sediment quality in a river network and may be correlated to the degree of urbanization represented by the number of inhabitants per total flux of suspended particles. Based on long-term on-line turbidity measurements mass flow rates of particle bound pollutants over time could be calculated. Results showed that by far the largest amount of pollutant loads occur at relative high turbidities > 100 NTU which are observed only during very short time periods. Therefore it is of particular importance not to miss these pronounced but rare events.

Rügner, Hermann; Schwientek, Marc; Grathwohl, Peter

2014-05-01

225

USA/FRG umbrella agreement for cooperation in GCR [Gas Cooled Reactor] development: Fuel, fission products and graphite subprogram. Part 1, Management meeting report: Part 2, Revised subprogram plan, Revision 10  

SciTech Connect

This Subprogram Plan describes cooperative work in the areas of HTR fuel and graphite development and fission product studies that is being carried out under US/FRG/Swiss Implementing Agreement for cooperation in Gas Cooled Reactor development. Only bilateral US/FRG cooperation is included, since it is the only active work in this subprogram area at this time. The cooperation has been in progress since February 1977. A number of Project Work Statements have been developed in each of the major areas of the subprogram, and work on many of them is in progress. The following specific areas are included in the scope of this plan: fuel development; graphite development; fission product release; and fission product behavior outside the fuel elements.

NONE

1986-05-01

226

Open-loop Stability of Time-based vs. Event-based Switching in Locomotion Nelson Rosa Jr. and Kevin M. Lynch  

E-print Network

similar dynamics, a well- designed walking robot might also be made to brachiate. This work is a step-link dynamic wall- climbing Gibbot robot that can achieve a "foothold" at any location in the vertical plane: A step by a compass-gait biped (left) and a swing by a two-link brachiator (right) on the same slope

Hartmann, Mitra J. Z.

227

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

NASA Astrophysics Data System (ADS)

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.

Riddell, K.; Hugenholtz, C.

2012-12-01

228

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

229

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

ERIC Educational Resources Information Center

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

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

2012-01-01

230

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

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.

Radu Ionicioiu

2010-12-03

231

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

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.

V. A. Kuz'menko

2010-12-10

232

Characterising Seismic Hazard Input for Analysis Risk to Multi-System Infrastructures: Application to Scenario Event-Based Models and extension to Probabilistic Risk  

NASA Astrophysics Data System (ADS)

The potential human and economic cost of earthquakes to complex urban infrastructures has been demonstrated in the most emphatic manner by recent large earthquakes such as that of Haiti (February 2010), Christchurch (September 2010 and February 2011) and Tohoku (March 2011). Consideration of seismic risk for a homogenous portfolio, such as a single building typology or infrastructure, or independent analyses of separate typologies or infrastructures, are insufficient to fully characterise the potential impacts that arise from inter-connected system failure. Individual elements of each infrastructure may be adversely affected by different facets of the ground motion (e.g. short-period acceleration, long-period displacement, cumulative energy input etc.). The accuracy and efficiency of the risk analysis is dependent on the ability to characterise these multiple features of the ground motion over a spatially distributed portfolio of elements. The modelling challenges raised by this extension to multi-system analysis of risk have been a key focus of the European Project "Systemic Seismic Vulnerability and Risk Analysis for Buildings, Lifeline Networks and Infrastructures Safety Gain (SYNER-G)", and are expected to be developed further within the Global Earthquake Model (GEM). Seismic performance of a spatially distributed infrastructure during an earthquake may be assessed by means of Monte Carlo simulation, in order to incorporate the aleatory variability of the ground motion into the network analysis. Methodologies for co-simulating large numbers of spatially cross-correlated ground motion fields are appraised, and their potential impacts on a spatially distributed portfolio of mixed building typologies assessed using idealised case study scenarios from California and Europe. Potential developments to incorporate correlation and uncertainty in site amplification and geotechnical hazard are also explored. Whilst the initial application of the seismic risk analysis is directed toward seismic scenarios, this methodology can be extended to the application of probabilistic analysis of seismic hazard and risk. These applications present new challenges in terms of both the theoretical and computational implementation. They also illustrate the need for the integration of seismic hazard and risk calculations into a common software platform capable of modelling the risk analysis from end-to-end. The development of OpenQuake, the open source hazard and risk calculation platform developed as part of GEM, provides such a means of integrating state-of-the-art hazard and risk calculators. The potential direction of future developments to this software will need to take into account many of the modelling issues raised in this discussion.

Weatherill, G. A.; Silva, V.

2011-12-01

233

A Framework for EventBased Software Integration Daniel J. Barrett, Lori A. Clarke, Peri L. Tarr, and Alexander E. Wise  

E-print Network

A Framework for Event­Based Software Integration Daniel J. Barrett, Lori A. Clarke, Peri L. Tarr F30602­94­C­0137. Name: Daniel J. Barrett Address: barrett@cs.umass.edu Name: Lori A. Clarke Address. Abstracting with credit is permitted. To copy otherwise, to republish, to post on servers, to redistribute

Massachusetts at Amherst, University of

234

Monitoring of event-based mobilization of hydrophobic pollutants in rivers: calibration of turbidity as a proxy for particle facilitated transport in field and laboratory.  

PubMed

Transport of many pollutants in rivers is coupled to mobilization of suspended particles which typically occurs during floods. Since the amount of total suspended solids (TSS) in rivers can be monitored by turbidity measurements this may be used as a proxy for the total concentration of particle associated pollutants such as PAHs, PCBs, etc. and several heavy metals. Online turbidity measurements (e.g. by optical backscattering sensors) would then also allow for an assessment of particle and pollutant flux dynamics if once calibrated against TSS and total pollutant concentrations for a given catchment. In this study, distinct flood and thus turbidity events were sampled at high temporal resolution in three contrasting sub-catchments of the River Neckar in Southwest Germany (Ammer, Goldersbach, Steinlach) as well as in the River Neckar itself and investigated for the total amount of PAHs and TSS in water; turbidity (NTU) and grain size distributions of suspended solids were determined as well. Laboratory experiments were performed with natural river bed sediments from different locations (Ammer) to investigate PAH concentrations, TSS and turbidity during sedimentation of suspended particles under controlled conditions (yielding smaller and smaller suspended particles and TSS with time). Laboratory and field results agreed very well and showed that turbidity and TSS were linearly correlated over an extended turbidity range up to 2000 NTU for the field samples and up to 8000 NTU in lab experiments. This also holds for total PAH concentrations which can be reasonably well predicted based on turbidity measurements and TSS vs. PAHs relationships - even for high turbidity values observed during flood events (>2000 NTU). Total PAH concentrations on suspended solids were independent of grain size of suspended particles. This implies that for the rivers investigated the sorption capacity of particles did not change significantly during the observed events. PMID:24858216

Rügner, Hermann; Schwientek, Marc; Egner, Marius; Grathwohl, Peter

2014-08-15

235

Generation of Polyclonal Antibodies Against Recombinant Human Glucocerebrosidase Produced in Escherichia coli  

Microsoft Academic Search

Deficiency of the lysosomal glucocerebrosidase (GCR) enzyme results in Gaucher’s disease, the most common inherited storage\\u000a disorder. Treatment consists of enzyme replacement therapy by the administration of recombinant GCR produced in Chinese hamster\\u000a ovary cells. The production of anti-GCR antibodies has already been described with placenta-derived human GCR that requires\\u000a successive chromatographic procedures. Here, we report a practical and efficient

Juliana Branco Novo; Maria Leonor Sarno Oliveira; Ligia Morganti; Isaías Raw; Paulo Lee Ho

2010-01-01

236

The First Intron of the Human Growth Hormone Gene Contains a Binding Site for Glucocorticoid Receptor  

Microsoft Academic Search

Glucocorticoid receptor (GCR) protein stimulates transcription from a variety of cellular genes. We show here that GCR partially purified from rat liver binds specifically to a site within the first intron of the human growth hormone (hGH) gene, ≈ 100 base pairs downstream from the start of hGH transcription. GCR binding is selectively inhibited by methylation of two short, symmetrically

David D. Moore; Andrew R. Marks; Douglas I. Buckley; Geoffrey Kapler; Farhang Payvar; Howard M. Goodman

1985-01-01

237

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

PubMed Central

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

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

2014-01-01

238

Migration process of very low-frequency events based on a chain-reaction model1 and its application to the detection of preseismic slip for megathrust earthquakes2  

E-print Network

University, Sendai 980-8578, Japan11 3 Seismological Laboratory, California Institute of Technology, Pasadena Hasegawa2 5 6 E-mail: ariyoshi@jamstec.go.jp7 1 Earthquake and Tsunami Research Project for Disaster Prevention, Japan Agency for8 Marine-Earth Science and Technology, Yokohama 236-0001, Japan9 2 Research

Ampuero, Jean Paul

239

46 CFR Table I to Part 150 - Alphabetical List of Cargoes  

Code of Federal Regulations, 2011 CFR

...GCR Polyisobutenamine in aliphatic (C10-C14) solvent7PIB Polyisobutenyl anhydride adduct11Poly(4+)isobutylene 30Polymethylene polyphenyl isocyanate12 PPIPolymethylsiloxane34 Polyolefin (molecular weight...

2011-10-01

240

46 CFR Table I to Part 150 - Alphabetical List of Cargoes  

Code of Federal Regulations, 2012 CFR

...GCR Polyisobutenamine in aliphatic (C10-C14) solvent7PIB Polyisobutenyl anhydride adduct11Poly(4+)isobutylene 30Polymethylene polyphenyl isocyanate12 PPIPolymethylsiloxane34 Polyolefin (molecular weight...

2012-10-01

241

Real Distribution of the Coronal Green Line Intensity and Modelling Study of Galactic Cosmic Ray Propagation  

NASA Astrophysics Data System (ADS)

transport equation of galactic cosmic rays (GCR) has been numerically solved for different qA>0 (1996) and qA<0 (1987) epochs assuming that free path of GCR scattering in the interplanetary space is controlled by the Sun's coronal green line intensity (CGLI). We found some distinctions in the distribution of the expected heliolatitudinal gradients of GCR for two and three dimensional interplanetary magnetic field. INTRODUCTION. modulation of GCR in the interplanetary space is generally determined by four processesdiffusion, convection, drift and energy change of GCR particles due to interaction with the solar wind. The joint effect of all above mentioned processes result the 11year variation of GCR. In papers [1-3] are assumed that the general reason of the 11-year variation of GCR in the energy range more than 1 GeV is different structure of the irregularities of the IMF in the maxima and minima epochs of solar activity (SA) caused the radical changes of the dependence of diffusion coefficient on the rigidity of GCR particles. EXPERIMENTAL DATA AND METHOD OF INVESTIGATION. experimental data of sunspot numbers, sunspots' areas and CGLI (? = 5303?) show a considerable changes during the 11-year cycle of SA, while e.g. A the changes of the solar wind velocity are not so noticeable [4, 5]. An attempt to take into account influences of the real distributions of the sunspot's areas and the Sun's CGLI on the modulation of GCR considering delay time of the phenomena in the interplanetary space with respect to the processes on the Sun have been undertaken in papers [6-8]. One of parameters of SA contentiously observed on the Earth is the Sun's CGLI. One can suppose that a modulation of GCR by some means is controlled by the changes of the CGLI; particularly there is assumed that a scattering free path of GCR transport is related with the

Gushchina, R. T.; Alania, M. V.; Gil, A.; Iskra, K.; Siluszyk, M.

2003-07-01

242

Development of a Miniaturized Hollow-Waveguide Gas Correlation Radiometer for Trace Gas Measurements in the Martian Atmosphere  

NASA Technical Reports Server (NTRS)

We present preliminary results in the development of a miniaturized gas correlation radiometer (GCR) for column trace gas measurements in the Martian atmosphere. The GCR is designed as an orbiting instrument capable of mapping multiple trace gases and identifying active regions on the Mars surface.

Wilson, Emily L.; Georgieva, E. M.; Blalock, G. W.; Marx, C. T.; Heaps, W. S.

2012-01-01

243

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...

244

Interplanetary Coronal Mass Ejections, Associated Features, and Transient Modulation of Galactic Cosmic Rays  

NASA Astrophysics Data System (ADS)

Interplanetary structures such as shocks, sheaths, interplanetary counterparts of coronal mass ejections (ICMEs), magnetic clouds, and corotating interaction regions (CIRs) are of special interest for the study of the transient modulation of galactic cosmic rays (GCRs). These structures modulate the GCR intensity with varying amplitudes and recovery-time profiles. It is known that ICMEs are mainly responsible for Forbush decreases in the GCR intensity. However, not all of the ICMEs produce such decreases in GCR intensity. We utilize GCR intensity data recorded by neutron monitors and solar-wind plasma/field data during the passage of ICMEs with different features and structures, and we perform a superposed-epoch analysis of the data. We also adopt the best-fit approach with suitable functions to interpret the observed similarities and differences in various parameters. Using the GCR-effectiveness as a measure of the cosmic-ray response to the passage of ICMEs, about half of the ICMEs identified during 1996 - 2009 are found to produce moderate to very large intensity depressions in GCR intensity. The ICMEs associated with halo CMEs, magnetic-cloud (MC) structures, bidirectional superthermal electron (BDE) signatures, and those driving shocks are 1.5 to 4 times more GCR effective than the ICMEs not associated with these structures/features. Further, the characteristic recovery time of GCR intensity due to shock/BDE/MC/halo-CME-associated ICMEs is larger than those due to ICMEs not associated with these structures/features.

Kumar, Anand; Badruddin

2014-06-01

245

Advances in Geosciences, 7, 157161, 2006 SRef-ID: 1680-7359/adgeo/2006-7-157  

E-print Network

to penetrate the in- ner solar system and reach the Earth. Thus, the GCR inten- sity is lower when solar to precipitable water availability. 1 Introduction Cosmic rays are energetic particles originating from both so- lar and non-solar sources. The latter are called galactic cos- mic rays (GCR) and come mainly from

Boyer, Edmond

246

Association of Basal Hyperglucagonemia with Impaired Glucagon Counterregulation in Type 1 Diabetes  

PubMed Central

Glucagon counterregulation (GCR) protects against hypoglycemia, but is impaired in type 1 diabetes (T1DM). A model-based analysis of in vivo animal data predicts that the GCR defects are linked to basal hyperglucagonemia. To test this hypothesis we studied the relationship between basal glucagon (BasG) and the GCR response to hypoglycemia in 29 hyperinsulinemic clamps in T1DM patients. Glucose levels were stabilized in euglycemia and then steadily lowered to 50?mg/dL. Glucagon was measured before induction of hypoglycemia and at 10?min intervals after glucose reached levels below 70?mg/dL. GCR was assessed by CumG, the cumulative glucagon levels above basal; MaxG, the maximum glucagon response; and RIG, the relative increase in glucagon over basal. Analysis of the results was performed with our mathematical model of GCR. The model describes interactions between islet peptides and glucose, reproduces the normal GCR axis and its impairment in diabetes. It was used to identify a control mechanism consistent with the observed link between BasG and GCR. Analysis of the clinical data showed that higher BasG was associated with lower GCR response. In particular, CumG and RIG correlated negatively with BasG (r?=??0.46, p?=?0.012 and r?=??0.74, p?GCR in which the secretion of glucagon has two components. The first is under (auto) feedback control and drives a pulsatile GCR and the second is feedback independent (basal secretion) and its increase suppresses the GCR. Our simulations showed that this model explains the observed relationships between BasG and GCR during a three-fold simulated increase in BasG. Our findings support the hypothesis that basal hyperglucagonemia contributes to the GCR impairment in T1DM and show that the predictive power of our GCR animal model applies to human pathophysiology in T1DM. PMID:22403550

Farhy, Leon S.; Chan, Alice; Breton, Marc D.; Anderson, Stacey M.; Kovatchev, Boris P.; McCall, Anthony L.

2012-01-01

247

Expression of glucocorticoid receptor ? and its regulation in the bovine endometrium: possible role in cyclic prostaglandin F2? production.  

PubMed

Cortisol (Cr), the most important glucocorticoid (GC), is well known to suppress uterine prostaglandin F2? (PGF) production. However, the details of the regulatory mechanisms controlling the cyclic changes in endometrial PGF production remain unclear. Here we investigated the expression of the GC receptor (GC-R?), the actions of cortisol throughout the estrous cycle and the regulatory mechanism of GC-R? in the bovine endometrium. The levels of GC-R? protein were greater at the mid-luteal stage (Days 8-12) than at the other stages. Cr more strongly suppressed PGF production at the mid-luteal stage than at the follicular stage. GC-R? expression was increased by progesterone (P4) but decreased by estradiol-17? (E2) in cultured endometrial stromal cells. The overall results suggest that ovarian steroid hormones control the cyclic changes in endometrial PGF production by regulating GC-R? expression in bovine endometrial stromal cells. PMID:23563496

Kuse, Mariko; Lee, Hwa-Yong; Acosta, Tomas J; Hojo, Takuo; Okuda, Kiyoshi

2013-01-01

248

Astrophysical Li-7 as a product of big bang nucleosynthesis and galactic cosmic-ray spallation  

NASA Technical Reports Server (NTRS)

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.

Olive, Keith A.; Schramm, David N.

1992-01-01

249

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

NASA Astrophysics Data System (ADS)

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.

Badruddin; Aslam, O. P. M.

2015-01-01

250

Modulation of Galactic Cosmic Rays Observed at L1 in Solar Cycle 23  

NASA Astrophysics Data System (ADS)

We analyze a unique 15 yr record of galactic cosmic-ray (GCR) measurements made by the SOHO Coronal Diagnostic Spectrometer NIS detectors, recording integrated GCR numbers with energies above 1.0 GeV between 1996 July and 2011 June. We are able to closely reproduce the main features of the SOHO/CDS GCR record using the modulation potential calculated from neutron monitor data by Usoskin et al. The GCR numbers show a clear solar cycle modulation: they decrease by 50% from the 1997 minimum to the 2000 maximum of the solar cycle, then return to the 1997 level in 2007 and continue to rise, in 2009 December reaching a level 25% higher than in 1997. This 25% increase is in contrast with the behavior of Ulysses/KET GCR protons extrapolated to 1 AU in the ecliptic plane, showing the same level in 2008-2009 as in 1997. The GCR numbers are inversely correlated with the tilt angle of the heliospheric current sheet. In particular, the continued increase of SOHO/CDS GCRs from 2007 until 2009 is correlated with the decrease of the minimum tilt angle from 30° in mid-2008 to 5° in late 2009. The GCR level then drops sharply from 2010 January, again consistent with a rapid increase of the tilt angle to over 35°. This shows that the extended 2008 solar minimum was different from the 1997 minimum in terms of the structure of the heliospheric current sheet.

Fludra, A.

2015-01-01

251

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)

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.

Koontz, Steve

2015-01-01

252

Pulsed Magnetic Field Driven Gas Core Reactors for Space Power & Propulsion Applications  

NASA Technical Reports Server (NTRS)

The present results indicated that: 1. A pulsed magnetic driven fission power concept, PMD-GCR is developed for closed (NER) and semi-open (NTR) operations. 2. In power mode, power is generated at alpha less than 1 for power levels of hundreds of KW or higher 3. IN semi open NTR mode, PMD-GCR generates thrust at I(sub sp) approx. 5,000 s and jet power approx. 5KW/Kg. 4. PMD-GCR is highly subcritical and is actively driven to critically. 5. Parallel path with fusion R&D needs in many areas including magnet and plasma.

Anghaie, Samim; Smith, Blair; Knight, Travis; Butler, Carey

2003-01-01

253

Drug delivery systems based on sugar-macromolecule conjugates Benjamin G Davis* & Mark A Robinson  

E-print Network

-Galactosamine GCR Glucocerebrosidase Glc D-Glucose GlcNAc N-Acetyl-D-glucosamine Glu Glutamate GPT Glutamic pyruvic nucleic acid PGE1 Prostaglandin E1 PVLA Poly(vinylbenzyl-lactonamide) rhIL-2 Recombinant human interleukin

Davis, Ben G.

254

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

PubMed Central

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

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

2014-01-01

255

W W W. N A T U R E . C O M / N A T U R E | 1 SUPPLEMENTARYINFORMATION doi:10.1038/nature12149  

E-print Network

to generate clones that will grow on plates containing 5-FOA and canavanine (FOA+Can). After standard GCR4 insert grew on ­Leu medium) but not on media containing FOA, Can, or both (data not shown). Thus-GCR pif1-m2 + G4, pif1-m2 rrm3 + G4, and pif1-m2 rrm3 clones demonstrated that they grew on FOA, Can

Kowalczykowski, Stephen C.

256

Grey Component Replacement Research, Modelling Tone And Color Reproduction  

NASA Astrophysics Data System (ADS)

Four different scanning Color Electronic Pagination System (CEPS) devices were tested to study their conventional and Grey Component Replacement/Undercolor Addition (GCR/UCA) tone and color response in the 4 color Positive Acting Offset Lithographic printing process. A common transparency input and ganged printing output was used. Inter and intra machine differences are disclosed. A new depiction of the full tone reproduction characteristics is presented for several different levels of GCR/UCA and conventional printing.

Fisch, Richard S.

1990-06-01

257

Galactic cosmic ray radiation levels in spacecraft on interplanetary missions  

NASA Technical Reports Server (NTRS)

Using the Langley Research Center Galactic Cosmic Ray (GCR) transport computer code (HZETRN) and the Computerized Anatomical Man (CAM) model, crew radiation levels inside manned spacecraft on interplanetary missions are estimated. These radiation-level estimates include particle fluxes, LET (Linear Energy Transfer) spectra, absorbed dose, and dose equivalent within various organs of interest in GCR protection studies. Changes in these radiation levels resulting from the use of various different types of shield materials are presented.

Shinn, J. L.; Nealy, J. E.; Townsend, L. W.; Wilson, J. W.; Wood, J.S.

1994-01-01

258

Experimental study and theoretical modeling of the long period variations of Galactic Cosmic Rays  

NASA Astrophysics Data System (ADS)

We analyze experimental data of neutron monitors and solar wind parameters during #21 solar cycle (1976-1987). In galactic cosmic ray (GCR) intensity is well established a step like changes in both ascending and descending periods of solar activity. We compose two-dimensional (2-D) time dependent model of GCR modulation based on Parker's transport equation to explain a general 11-year wave of the GCR intensity with the step-like changes, and each step-like changes individually, i.e. time scale of investigations is carried out by means of daily and monthly data. An innovation in proposed model is that besides the well known fundamental processes responsible for modulation of the GCR intensity, we implement in the model the parameters characterizing temporal changes of the exponent n of the Power Spectral Density (PSD) of the Interplanetary Magnetic Field (IMF) turbulence, module B of the IMF, tilt angle ? of the Heliospheric Neutral Sheet, and changes of drift effect of the GCR particles upon solar activity assuming that drift effect of the GCR particles is maximal in the minimum epoch, when drift dominates, and is neglected in the maximum epoch, when diffusion dominates. We show that an acceptable compatibility is kept for the investigated period of 1976-1987 (solar cycle #21), when the expected temporal changes of the GCR particles density (11-year wave) is shifted for 18 months with respect to the temporal changes of the smoothed experimental data of the GCR intensity. We consider, that a delay time ˜18 months can be considered as an effective delay time caused by the combined influence of all parameters implemented in the 2-D model.

Alania, Michael; Siluszyk, Marek; Wawrzynczak-Szaban, Anna

2012-07-01

259

The boron-to-beryllium ratio in halo stars - A signature of cosmic-ray nucleosynthesis in the early Galaxy  

NASA Technical Reports Server (NTRS)

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.

Walker, T. P.; Steigman, G.; Schramm, D. N.; Olive, K. A.; Fields, B.

1993-01-01

260

Computational and Genetic Reduction of a Cell Cycle to Its Simplest, Primordial Components  

PubMed Central

What are the minimal requirements to sustain an asymmetric cell cycle? Here we use mathematical modelling and forward genetics to reduce an asymmetric cell cycle to its simplest, primordial components. In the Alphaproteobacterium Caulobacter crescentus, cell cycle progression is believed to be controlled by a cyclical genetic circuit comprising four essential master regulators. Unexpectedly, our in silico modelling predicted that one of these regulators, GcrA, is in fact dispensable. We confirmed this experimentally, finding that ?gcrA cells are viable, but slow-growing and elongated, with the latter mostly due to an insufficiency of a key cell division protein. Furthermore, suppressor analysis showed that another cell cycle regulator, the methyltransferase CcrM, is similarly dispensable with simultaneous gcrA/ccrM disruption ameliorating the cytokinetic and growth defect of ?gcrA cells. Within the Alphaproteobacteria, gcrA and ccrM are consistently present or absent together, rather than either gene being present alone, suggesting that gcrA/ccrM constitutes an independent, dispensable genetic module. Together our approaches unveil the essential elements of a primordial asymmetric cell cycle that should help illuminate more complex cell cycles. PMID:24415923

Fumeaux, Coralie; Viollier, Patrick H.; Howard, Martin

2013-01-01

261

Effects of Cutoffs on Galactic Cosmic-Ray Interactions in Solar-System Matter  

NASA Technical Reports Server (NTRS)

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.

Kim, K. J.; Reedy, R. C.; Masarik, J.

2005-01-01

262

Orbiting Astrophysical Spectrometer in Space (OASIS)  

NASA Astrophysics Data System (ADS)

NASA has selected the Orbiting Astrophysical Spectrometer in Space (OASIS) mission for study as an astrophysics strategic mission concept, to determine its feasibility and cost. The goal of the OASIS mission is to identify the local site or sites where galactic cosmic rays (GCRs) originate and are accelerated. This will allow GCR data to be used to refine our understanding of supernovae and nucleosynthesis. OASIS will also investigate GCR acceleration and transport using measurements of the composition of ultra-heavy nuclei, the ratio of boron to carbon (B/C) and the energy spectrum of electrons. OASIS will measure the relative abundances in the actinide group to determine the age of the r-process material in GCRs. The B/C ratio measures how the GCR composition was altered by nuclear interactions during transport from their source to Earth. The presence of young r-process material would indicate that GCRs are a sample of the interstellar medium in OB associations. OASIS will identify the nearest GCR sources by following the GCR electron spectrum to its high-energy end. OASIS will also look for anisotropy and features at the high energy end of the spectrum that are predicted for the nearest sources. The actinide composition will be measured using a combination of silicon detectors, a scintillating fiber hodoscope and Cherenkov detectors. The GCR electron spectrum will be measured using an ionization calorimeter consisting of tungsten and silicon strip detectors. Details of OASIS will be presented along with its expected performance.

Adams, James; Adams, James; Barbier, Louis; Binns, Walter; Guzik, T. Gregory; Hams, Thomas; Isbert, Joachim; Mewaldt, R. A.; Mitchell, John; Sasaki, Makoto; Stone, Edward; Wefel, John P.; Wiedenbeck, Mark; Adams, Robert; Alexander, Reginald; Cherry, Michael; Christl, Mark; de Nolfo, Gerogia; Elrod, Stephen; Israel, Martin; Krizmanic, John; Link, Jason; Moiseev, Alexander; Stochaj, Steve; Streitmatter, Robert; Watts, John

263

Near-Earth Cosmic Ray Decreases Associated with Remote Coronal Mass Ejections  

NASA Astrophysics Data System (ADS)

Galactic cosmic ray (GCR) flux is modulated by both particle drift patterns and solar wind structures on a range of timescales. Over solar cycles, GCR flux varies as a function of the total open solar magnetic flux and the latitudinal extent of the heliospheric current sheet. Over hours, drops of a few percent in near-Earth GCR flux (Forbush decreases, FDs) are well known to be associated with the near-Earth passage of solar wind structures resulting from corotating interaction regions (CIRs) and transient coronal mass ejections (CMEs). We report on four FDs seen at ground-based neutron monitors which cannot be immediately associated with significant structures in the local solar wind. Similarly, there are significant near-Earth structures which do not produce any corresponding GCR variation. Three of the FDs are during the STEREO era, enabling in situ and remote observations from three well-separated heliospheric locations. Extremely large CMEs passed the STEREO-A spacecraft, which was behind the West limb of the Sun, approximately 2-3 days before each near-Earth FD. Solar wind simulations suggest that the CMEs combined with pre-existing CIRs, enhancing the pre-existing barriers to GCR propagation. Thus these observations provide strong evidence for the modulation of GCR flux by remote solar wind structures.

Thomas, S. R.; Owens, M. J.; Lockwood, M.; Barnard, L.; Scott, C. J.

2015-03-01

264

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

NASA Astrophysics Data System (ADS)

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.

Chaudhuri, Sutapa; Pal, Jayanti; Guhathakurta, Suchandra

2015-02-01

265

Analysis distribution of galactic cosmic rays particle energy with polar orbit satellite for Geant4 application  

NASA Astrophysics Data System (ADS)

Galactic Cosmic Rays (GCR) are photon waves originating from astrophysical sources which traverse through the interstellar/interplanetary medium and reaching the terrestrial atmosphere. The energies of Galactic Cosmic Ray particles up to and exceeding 1012 eV, and this spectrum are peaked around 1 GeV. The National Aeronautics and Space Administration (NASA) provide satellite mission for monitoring the energy GCR particles in polar orbit, so-called the ACE and OMNI. In this paper, we analyze results from measurement error of GCR sensor. The error result is obtained by comparing the measurements from GCR sensor with ground-based neutron monitors at Bartol University. The measurements were taken for two periods during a Solar Particle Event (SPE) maximum on 14 July 2000 and 28 October 2003. The largest value of measurement error from GCR sensor in this study is OMNI satellites. After the error results were obtained, they were applied into Geant4 simulation. This simulation shows the shape of particle energy distribution of GCR sensors. The simulation has been tested and can be operated very well under Linux based platform.

Suparta, W.; Putro, W. S.

2014-04-01

266

Cosmic rays linked to rapid mid-latitude cloud changes  

NASA Astrophysics Data System (ADS)

The effect of the Galactic Cosmic Ray (GCR) flux on Earth's climate is highly uncertain. Using a novel sampling approach based around observing periods of significant cloud changes, a statistically robust relationship is identified between the rate of GCR flux and the most rapid mid-latitude (60°-30° N/S) cloud decreases operating over daily timescales; this signal is verified in surface level air temperature (SLAT) reanalysis data. A General Circulation Model experiment is used to test the causal relationship of the observed cloud changes to the detected SLAT anomalies. Results indicate that the cloud anomalies were responsible for producing the observed SLAT changes, implying a link between significant decreases in the rate of GCR flux (~0.79%/day (relative to the peak-to-peak amplitude of 11-yr solar cycle)), decreases in cloud cover (~1.9%/day) and increases in SLAT (~0.05 K/day). The influence of GCRs is clearly distinguishable from changes in solar irradiance and the interplanetary magnetic field. These results provide the most compelling evidence presented thus far of a GCR-climate relationship. From this analysis we conclude: (i) a GCR-climate relationship is governed by both the rate of GCR flux and internal precursor conditions; and (ii) it is likely that this natural forcing has not contributed significantly to recent anthropogenic temperature rises.

Laken, B. A.; Kniveton, D. R.; Frogley, M. R.

2010-08-01

267

NASA Galactic Cosmic Radiation Environment Model: Badhwar-O'Neill (2014)  

NASA Technical Reports Server (NTRS)

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.

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

2015-01-01

268

Implementing Badhwar-O'Neill Galactic Cosmic Ray Model for the Analysis of Space Radiation Exposure  

NASA Technical Reports Server (NTRS)

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.

Kim, Myung-Hee Y.; O'Neill, Patrick M.; Slaba, Tony C.

2014-01-01

269

Calculation of The Ti Activity In 44 Chondrites Which Fell In The Last Two Centuries and Comparison With Measurements  

NASA Astrophysics Data System (ADS)

The cosmogenic radioisotopes in meteorites, produced by nuclear interactions of the galactic cosmic rays (GCR) with the meteoroids in the interplanetary space are good proxies of both the GCR flux and the solar activity. Different cosmogenic radionu- clides with different half-lives give information over different time scales. Recently we have inferred the GCR annual mean spectra for the last 300 years [1]. The most prominent result concerns the cosmic ray flux during prolonged solar quiet periods. We deduced that during the Maunder minimum of solar acivity (1700), the Dal- ton minimum (1800) and the Modern minimum (1900) the GCR flux was much higher (2 times) respect to the flux observed in the last decades. Utilizing these GCR spectra we have calculated the 44 Ti (T1/2 = 59.2 y) activity in meteorites taking into account its exitation function for production from the main target element Fe, Ni and Ti [2]. Furthermore, in the last years we have measured the very low activity of the cosmogenic 44Ti in different fell chondrites and now our data cover the interval 1810 to present. The calculated 44Ti profile is in close agreement with the observed mea- surements. This result demonstrates that our inference of the GCR flux in the past 300 years is reliable. The cosmogenic 44Ti in meteorites is a unique tool, free from ter- restrial influences, for validation of both the GCR flux and the heliospheric behaviour over century time scale. [1] G. Bonino, G. Cini Castagnoli, D. Cane, C. Taricco and N. Bhandari, Proc. XXVII Intern. Cosmic Ray Conf. (Hamburg, 2001) 3769-3772. [2] R. Michel and S. Neumann (1998) Proc. Indian Acad. Sci. Earth Planet. Sci. , 107, 441-457.

Bonino, G.; Cane, D.; Cini Castagnoli, G.; Taricco, C.; Bhandari, N.

270

Badhwar-O'Neill 2011 Galactic Cosmic Ray Model Update and Future Improvements  

NASA Technical Reports Server (NTRS)

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.

O'Neill, Pat M.; Kim, Myung-Hee Y.

2014-01-01

271

Movement patterns of wintering lesser scaup in Grand Calumet River - Indiana Harbor Canal, Indiana  

USGS Publications Warehouse

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.

Custer, Christine M.; Custer, T.W.; Sparks, D.W.; Hines, Randy K.; Kochanny, C.O.

1996-01-01

272

The nanoparticulation by octaarginine-modified liposome improves ?-galactosylceramide-mediated antitumor therapy via systemic administration.  

PubMed

Alpha-galactosylceramide (?GC), a lipid antigen present on CD1d molecules, is predicted to have clinical applications as a new class of adjuvant, because ?GC strongly activates natural killer T (NKT) cells which produce large amounts of IFN-?. Here, we incorporated ?GC into stearylated octaarginine-modified liposomes (R8-Lip), our original delivery system developed for vaccines, and investigated the effect of nanoparticulation. Unexpectedly, the systemic administered R8-Lip incorporating ?GC (?GC/R8-Lip) failed to improve the immune responses mediated by ?GC compared with soluble ?GC in vivo, although ?GC/R8-Lip drastically enhanced ?GC presentation on CD1d in antigen presenting cells in vitro. Thus, we optimized the ?GC/R8-Lip in vivo to overcome this inverse correlation. In optimization in vivo, we found that size control of liposome and R8-modification were critical for enhancing the production of IFN-?. The optimization led to the accumulation of ?GC/R8-Lip in the spleen and a positive therapeutic effect against highly malignant B16 melanoma cells. The optimized ?GC/R8-Lip also enhanced ?GC presentation on CD1d in antigen presenting cells and resulted in an expansion in the population of NKT cells. Herein, we show that R8-Lip is a potent delivery system, and size control and R8-modification in liposomal construction are promising techniques for achieving systemic ?GC therapy. PMID:23860186

Nakamura, Takashi; Yamazaki, Daiki; Yamauchi, Jun; Harashima, Hideyoshi

2013-10-28

273

Search for cosmogenic Ar-42 in meteorites  

NASA Astrophysics Data System (ADS)

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

Cini Castagnoli, G.; Cane, D.; Taricco, C.; Bhandari, N.

2003-04-01

274

Features of the Diffusion Processes of the Galactic Cosmic Rays around 21/22, 22/23 and 23/24 Solar Minima Epochs: 2-D Modeling and Experimental Study  

NASA Astrophysics Data System (ADS)

We study changes of perpendicular and parallel diffusion coefficients versus the different structure of the Interplanetary Magnetic Field (IMF) in ascending and descending periods of solar activity. We find periods when sub and super diffusion nature for Galactic Cosmic Rays (GCR) propagation in heliosphere distinct from each other in positive and negative polarities of solar magnetic activity for GCR particles to which neutron monitors and ground muon telescopes respond. We study different pairs of ascending and descending periods around various minima epochs (21/22, 22/23 and 23/24) comparing timelines of the exponent nu of the Power Spectral Density (PSD f (-nu) ) of the IMF and the changes of the rigidity R spectrum exponent gamma of the GCR isotropic intensity variations (deltaD(R)/D(R) R (-gamma) ). It is demonstrated that decay and creation processes of the IMF turbulence structure defer from each other for ascending and descending periods. We show that there are periods with cases of dominant sub diffusion processes over normal markovian one. We develop two-dimensional (2D) time dependent model to describe the long period variations of the GCR intensity with a new proposal to take into account a delay time among the GCR intensity changes, on one side and parameters of solar wind and solar activity (e.g. interplanetary magnetic field, tilt angle), on the other. We also attempt to take into account in modeling a more realistic role of drift during different phases of the 11-year cycle of solar activity.

Siluszyk, Marek; Alania, Michael; Iskra, Krzysztof

275

The orphan protein bis-?-glutamylcystine reductase joins the pyridine nucleotide-disulfide reductase family  

PubMed Central

Facile DNA sequencing became possible decades after many enzymes had been purified and characterized. Consequently, there are still “orphan” enyzmes whose activity is known but the genes that encode them have not been identified. Identification of the genes encoding orphan enzymes is important because it allows correct annotation of genes of unknown function or with mis-assigned function. Bis-?-glutamylcystine reductase (GCR) is an orphan protein that was purified in 1988. This enzyme catalyzes the reduction of bis-?-glutamylcystine. ?-Glutamylcysteine (?-Glu-Cys) is the major low molecular weight thiol in halobacteria. We purified GCR from Halobacterium sp. NRC-1 and identified the sequence of 23 tryptic peptides by NanoLC electrospray ionization tandem mass spectrometry. These peptides cover 62% of the protein predicted to be encoded by a gene in Halobacterium sp. NRC-1 that is annotated as mercuric reductase. GCR and mercuric reductase activities were assayed using enzyme that was expressed in E. coli and re-folded from inclusion bodies. The enzyme had robust GCR activity, but no mercuric reductase activity. The genomes of most, but not all, halobacteria for which whole genome sequences are available have close homologs of GCR, suggesting that there is more to be learned about the low molecular weight thiols used in halobacteria. PMID:23560638

Kim, Juhan; Copley, Shelley D.

2014-01-01

276

Generation of a Chinese hamster ovary cell line producing recombinant human glucocerebrosidase.  

PubMed

Impaired activity of the lysosomal enzyme glucocerebrosidase (GCR) results in the inherited metabolic disorder known as Gaucher disease. Current treatment consists of enzyme replacement therapy by administration of exogenous GCR. Although effective, it is exceptionally expensive, and patients worldwide have a limited access to this medicine. In Brazil, the public healthcare system provides the drug free of charge for all Gaucher's patients, which reaches the order of $ 84 million per year. However, the production of GCR by public institutions in Brazil would reduce significantly the therapy costs. Here, we describe a robust protocol for the generation of a cell line producing recombinant human GCR. The protein was expressed in CHO-DXB11 (dhfr(-)) cells after stable transfection and gene amplification with methotrexate. As expected, glycosylated GCR was detected by immunoblotting assay both as cell-associated (~64 and 59 kDa) and secreted (63-69 kDa) form. Analysis of subclones allowed the selection of stable CHO cells producing a secreted functional enzyme, with a calculated productivity of 5.14 pg/cell/day for the highest producer. Although being laborious, traditional methods of screening high-producing recombinant cells may represent a valuable alternative to generate expensive biopharmaceuticals in countries with limited resources. PMID:23091360

Novo, Juliana Branco; Morganti, Ligia; Moro, Ana Maria; Paes Leme, Adriana Franco; Serrano, Solange Maria de Toledo; Raw, Isaias; Ho, Paulo Lee

2012-01-01

277

Nuclide production by primary cosmic-ray protons  

SciTech Connect

The production rates of cosmogenic nuclides in the solar system and in interstellar space were calculated for the primary protons in the galactic and solar cosmic rays. At 1 AU, the long-term average fluxes of solar protons usually produce many more atoms of a cosmogenic nuclide than the primary protons in the galactic cosmic rays (GCR), the exceptions being nuclides made only by high-energy reactions (like /sup 10/Be). Because the particle fluxes inside meteorites and other large objects in space include many secondary neutrons, the production rates are much higher and ratios inside large objects are often very different from those by just the primary GCR protons in small objects. The production rates of cosmogenic nuclides are calculated to vary by about factors of 2.5 during at typical 11-year solar cycle, in agreement with measurements of short-lived radionuclides in recently fallen meteorites. The production of cosmogenic nuclides by the GCR particles outside the heliosphere is higher than that by the modulated GCR primaries normally in the solar system. However, there is considerable uncertainty in the fluxes of interstellar protons and, therefore, in the production rates of cosmogenic nuclides in interstellar space. Production rates and ratios for cosmogenic nuclides would be able to identify particles that were small in space or that were exposed to an unmodulated spectrum of GCR particles. 25 refs., 2 figs., 2 tabs.

Reedy, R.C.

1986-01-01

278

Evaluating Shielding Effectiveness for Reducing Space Radiation Cancer Risks  

NASA Technical Reports Server (NTRS)

We discuss calculations of probability distribution functions (PDF) representing uncertainties in projecting fatal cancer risk from galactic cosmic rays (GCR) and solar particle events (SPE). The PDF s are used in significance tests of the effectiveness of potential radiation shielding approaches. Uncertainties in risk coefficients determined from epidemiology data, dose and dose-rate reduction factors, quality factors, and physics models of radiation environments are considered in models of cancer risk PDF s. Competing mortality risks and functional correlations in radiation quality factor uncertainties are treated in the calculations. We show that the cancer risk uncertainty, defined as the ratio of the 95% confidence level (CL) to the point estimate is about 4-fold for lunar and Mars mission risk projections. For short-stay lunar missions (<180 d), SPE s present the most significant risk, however one that is mitigated effectively by shielding, especially for carbon composites structures with high hydrogen content. In contrast, for long duration lunar (>180 d) or Mars missions, GCR risks may exceed radiation risk limits, with 95% CL s exceeding 10% fatal risk for males and females on a Mars mission. For reducing GCR cancer risks, shielding materials are marginally effective because of the penetrating nature of GCR and secondary radiation produced in tissue by relativistic particles. At the present time, polyethylene or carbon composite shielding can not be shown to significantly reduce risk compared to aluminum shielding based on a significance test that accounts for radiobiology uncertainties in GCR risk projection.

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

2007-01-01

279

Depth-dose equivalent relationship for cosmic rays at various solar minima  

NASA Technical Reports Server (NTRS)

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.

Badhwar, G. D.; Cucinotta, F. A.; O'Neill, P. M.

1993-01-01

280

Diffusion coefficient and radial gradient of galactic cosmic rays  

E-print Network

We present the temporal changes of the diffusion coefficient K of galactic cosmic rays (GCRs) at the Earth orbit calculated based on the experimental data using two different methods. The first approach is based on the Parker convection-diffusion approximation of GCR modulation [1]: i.e. K~Vr=dI where dI is the variation of the GCR intensity measured by neutron monitors (NM),V is the solar wind velocity and r is the radial distance. The second approach is based on the interplanetary magnetic field (IMF) data. It was suggested that parallel mean free path can be expressed in terms of B as in [2]-[4]. Using data of the product of the parallel mean free path and radial gradient of GCR calculated based on the GCR anisotropy data (Ahluwalia et al., this conference ICRC 2013, poster ID: 487 [5]), we estimate the temporal changes of the radial gradient of GCR at the Earth orbit. We show that the radial gradient exhibits a strong solar cycle dependence (11-year variation) and a weak solar magnetic cycle dependence (2...

Modzelewska, Renata

2015-01-01

281

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)

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.

Veretenenko, S.; Ogurtsov, M.

2014-12-01

282

The phosphorus/sulfur abundance ratio as a test of galactic cosmic-ray source models  

NASA Astrophysics Data System (ADS)

Galactic cosmic-ray (GCR) elemental abundances display a fractionation compared to solar-system values that appears ordered by atomic properties such as the first ionization potential (FIP) or condensation temperature (volatility). Determining which parameter controls the observed fractionation is crucial to distinguish between GCR origin models. The Cosmic-Ray Isotope Spectrometer (CRIS) instrument on board NASA's Advanced Composition Explorer (ACE) spacecraft can measure the abundances of several elements that break the general correlation between FIP and volatility (e.g., Na, P, K, Cu, Zn, Ga, and Ge). Phosphorus is a particularly interesting case as it is a refractory (high condensation temperature) element with a FIP value nearly identical to that of its semi-volatile neighbor, sulfur. Using a leaky-box galactic propagation model we find that the P/S and Na/Mg ratios in the GCR source favor volatility as the controlling parameter. .

George, J. S.; Wiedenbeck, M. E.; Binns, W. R.; Christian, E. R.; Cummings, A. C.; Hink, P. L.; Leske, R. A.; Mewaldt, R. A.; Stone, E. C.; von Rosenvinge, T. T.; Yanasak, N. E.

2001-11-01

283

Cellular track model of biological damage to mammalian cell cultures from galactic cosmic rays  

NASA Technical Reports Server (NTRS)

The assessment of biological damage from the galactic cosmic rays (GCR) is a current interest for exploratory class space missions where the highly ionizing, high-energy, high-charge ions (HZE) particles are the major concern. The relative biological effectiveness (RBE) values determined by ground-based experiments with HZE particles are well described by a parametric track theory of cell inactivation. Using the track model and a deterministic GCR transport code, the biological damage to mammalian cell cultures is considered for 1 year in free space at solar minimum for typical spacecraft shielding. Included are the effects of projectile and target fragmentation. The RBE values for the GCR spectrum which are fluence-dependent in the track model are found to be more severe than the quality factors identified by the International Commission on Radiological Protection publication 26 and seem to obey a simple scaling law with the duration period in free space.

Cucinotta, Francis A.; Katz, Robert; Wilson, John W.; Townsend, Lawrence W.; Nealy, John E.; Shinn, Judy L.

1991-01-01

284

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

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.

Alania, M V; Wawrzynczak, A

2015-01-01

285

Mars surface radiation exposure for solar maximum conditions and 1989 solar proton events.  

NASA Astrophysics Data System (ADS)

The Langley heavy-ion/nucleon and the high-energy nucleon transport codes 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 August, September, and October 1989 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.

Simonsen, L. C.; Nealy, J. E.

1993-02-01

286

Revised Production Rates for Na-22 and Mn-54 in Meteorites Using Cross Sections Measured for Neutron-induced Reactions  

NASA Technical Reports Server (NTRS)

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.

Sisterson, J. M.; Kim, K. J.; Reedy, R. C.

2004-01-01

287

The Development of Materials for Structures and Radiation Shielding in Aerospace  

NASA Technical Reports Server (NTRS)

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.

Kiefer, Richard L.; Orwoll, Robert A.

2001-01-01

288

The knee in the Galactic cosmic ray spectrum and variety in Supernovae  

NASA Astrophysics Data System (ADS)

This paper proposes a qualitative and quantitative solution of a long-standing problem in astrophysics: the origin of the knee in the Galactic cosmic ray (GCR) spectrum. We calculate GCR flux averaged over Supernova explosion energies and types, applying only the formulae of the standard model of CR acceleration in Supernova remnants (SNR) and the latest astronomical data on the variety in Supernovae. For this purpose we estimate the distribution of SNe in explosion energies and show this distribution to be probably a very asymmetric function with large dispersion. In the case under consideration the cosmic ray flux in the whole energy range should be predominantly formed by the most energetic SN explosions. The knee in the GCR spectrum at energy around E_knee=3 PeV can quantitatively be explained by the dominant contribution of Hypernovae. The model sketches the all-particle cosmic ray spectrum up to 1018 eV.

Sveshnikova, L. G.

2003-10-01

289

Updated Computational Model of Cosmic Rays Near Earth  

NASA Technical Reports Server (NTRS)

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.

ONeill, Patrick M.

2006-01-01

290

Modulation of UK lightning by heliospheric magnetic field polarity  

NASA Astrophysics Data System (ADS)

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 40–60% 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.

Owens, M. J.; Scott, C. J.; Lockwood, M.; Barnard, L.; Harrison, R. G.; Nicoll, K.; Watt, C.; Bennett, A. J.

2014-11-01

291

Stopping powers and cross sections due to two-photon processes in relativistic nucleus-nucleus collision  

NASA Technical Reports Server (NTRS)

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.

Cheung, Wang K.; Norbury, John W.

1992-01-01

292

Cycling Changes in the Amplitudes of the 27-Day Variation of the Galactic Cosmic Ray Intensity  

NASA Astrophysics Data System (ADS)

We study quasi-periodical changes in the amplitudes of the 27-day variation of the galactic cosmic ray (GCR) intensity, and the parameters of solar wind and solar activity. We have recently found quasi-periodicity of three to four Carrington rotation periods (3 - 4 CRP) in the amplitudes of the 27-day variation of the GCR intensity (Gil and Alania in J. Atmos. Solar-Terr. Phys. 73, 294, 2011). A similar recurrence is recognized in parameters of solar activity (sunspot number, solar radio flux) and solar wind (components of the interplanetary magnetic field, solar wind velocity). We believe that the 3 - 4 CRP periodicity, among other periodicities, observed in the amplitudes of the 27-day variation of the GCR intensity is caused by a specific cycling structure of the Sun's magnetic field, which may originate from the turbulent nature of the solar dynamo.

Gil, A.; Alania, M. V.

2012-06-01

293

Experimental Plans for Subsystems of a Shock Wave Driven Gas Core Reactor  

NASA Technical Reports Server (NTRS)

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).

Kazeminezhad, F.; Anghai, S.

2008-01-01

294

Expression and Dexamethasone-induced Nuclear Translocation of Glucocorticoid and Mineralocorticoid Receptors in Guinea Pig Cochlear Cells  

PubMed Central

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

Kil, Sung-Hee; Kalinec, Federico

2013-01-01

295

Occurrence of Antimicrobial-Resistant Escherichia coli and Salmonella enterica in the Beef Cattle Production and Processing Continuum.  

PubMed

Specific concerns have been raised that third-generation cephalosporin-resistant (3GC(r)) Escherichia coli, trimethoprim-sulfamethoxazole-resistant (COT(r)) E. coli, 3GC(r) Salmonella enterica, and nalidixic acid-resistant (NAL(r)) 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. 3GC(r) Salmonella was detected on 7.6% of hides during processing and was not detected on the final carcasses or strip loins. NAL(r) S. enterica was detected on only one hide. 3GC(r) E. coli and COT(r) E. coli were detected on 100.0% of hides during processing. Concentrations of 3GC(r) E. coli and COT(r) E. coli on hides were correlated with pre-evisceration carcass contamination. 3GC(r) E. coli and COT(r) 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 COT(r) 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

Schmidt, John W; Agga, Getahun E; Bosilevac, Joseph M; Brichta-Harhay, Dayna M; Shackelford, Steven D; Wang, Rong; Wheeler, Tommy L; Arthur, Terrance M

2015-01-01

296

A membrane glucocorticoid receptor mediates the rapid/non-genomic actions of glucocorticoids in mammalian skeletal muscle fibres  

PubMed Central

Glucocorticoids (GCs) are steroid hormones released from the adrenal gland in response to stress. They are also some of the most potent anti-inflammatory and immunosuppressive drugs currently in clinical use. They exert most of their physiological and pharmacological actions through the classical/genomic pathway. However, they also have rapid/non-genomic actions whose physiological and pharmacological functions are still poorly understood. Therefore, the primary aim of this study was to investigate the rapid/non-genomic effects of two widely prescribed glucocorticoids, beclomethasone dipropionate (BDP) and prednisolone acetate (PDNA), on force production in isolated, intact, mouse skeletal muscle fibre bundles. The results show that the effects of both GCs on maximum isometric force (Po) were fibre-type dependent. Thus, they increased Po in the slow-twitch fibre bundles without significantly affecting that of the fast-twitch fibre bundles. The increase in Po occurred within 10 min and was insensitive to the transcriptional inhibitor actinomycin D. Also, it was maximal at ?250 nm and was blocked by the glucocorticoid receptor (GCR) inhibitor RU486 and a monoclonal anti-GCR, suggesting that it was mediated by a membrane (m) GCR. Both muscle fibre types expressed a cytosolic GCR. However, a mGCR was present only in the slow-twitch fibres. The receptor was more abundant in oxidative than in glycolytic fibres and was confined mainly to the periphery of the fibres where it co-localised with laminin. From these findings we conclude that the rapid/non-genomic actions of GCs are mediated by a mGCR and that they are physiologically/therapeutically beneficial, especially in slow-twitch muscle fibres. PMID:23878367

Pérez, María Hernández-Alcalá; Cormack, Jonathan; Mallinson, David; Mutungi, Gabriel

2013-01-01

297

Assessment of galactic cosmic ray models  

NASA Astrophysics Data System (ADS)

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.

Mrigakshi, Alankrita Isha; Matthiä, Daniel; Berger, Thomas; Reitz, Günther; Wimmer-Schweingruber, Robert F.

2012-08-01

298

Cosmic rays linked to rapid mid-latitude cloud changes  

NASA Astrophysics Data System (ADS)

The effect of the Galactic Cosmic Ray (GCR) flux on Earth's climate is highly uncertain. Using a novel sampling approach based around observing periods of significant cloud changes, a statistically robust relationship is identified between short-term GCR flux changes and the most rapid mid-latitude (60°-30° N/S) cloud decreases operating over daily timescales; this signal is verified in surface level air temperature (SLAT) reanalysis data. A General Circulation Model (GCM) experiment is used to test the causal relationship of the observed cloud changes to the detected SLAT anomalies. Results indicate that the anomalous cloud changes were responsible for producing the observed SLAT changes, implying that if there is a causal relationship between significant decreases in the rate of GCR flux (~0.79 GU, where GU denotes a change of 1% of the 11-year solar cycle amplitude in four days) and decreases in cloud cover (~1.9 CU, where CU denotes a change of 1% cloud cover in four days), an increase in SLAT (~0.05 KU, where KU denotes a temperature change of 1 K in four days) can be expected. The influence of GCRs is clearly distinguishable from changes in solar irradiance and the interplanetary magnetic field. However, the results of the GCM experiment are found to be somewhat limited by the ability of the model to successfully reproduce observed cloud cover. These results provide perhaps the most compelling evidence presented thus far of a GCR-climate relationship. From this analysis we conclude that a GCR-climate relationship is governed by both short-term GCR changes and internal atmospheric precursor conditions.

Laken, B. A.; Kniveton, D. R.; Frogley, M. R.

2010-11-01

299

Three dimensional non stationary mathematical model describing Forbush decreases of galactic cosmic ray intensity  

NASA Astrophysics Data System (ADS)

Using experimental data we show that there exist a clear dependence of the exponent ? of the rigidity R spectrum ?D(R)-D(R) ? R-? of the Forbush decrease (Fd) of the galactic cosmic ray (GCR) intensity on the exponent ? of the Power Spectral Density (PSD) of the interplanetary magnetic field (IMF). To confirm this finding by theoretical study we propose a three dimensional (3D) non stationary model of the Fd of GCR intensity based on the Parker's transport equation taking into account diffusion, convection, drifts due to gradient and curvature of the IMF, and on the heliospheric neutral sheet with the energy changes in the diverged solar wind. This model implements the parameter describing the temporal changes of the IMF turbulence via the exponent ? of the PSD of the IMF. Owing to this innovation we confirm a relationship between the rigidity spectrum exponent ? and the exponent ? based on the numerical solutions of the 3D non stationary model of Fd. Also, we show that an increase of the size of the disturbed vicinity of the space causes the hardening of the rigidity spectrum of the Fd; namely, an increase of the size of the disturbed vicinity involves GCR particles with relatively larger larmour radius (in other equal conditions), so the GCR particles with the higher rigidities are modulated, which leads to the hardening of the rigidity spectrum (decreases). We find that for the higher rigidities of GCR particles a recovery time of the Fd is less than for the lower rigidities; a rate of the intensity reduction decreases with the increase of the diffusion coefficient and increasing GCR particle's rigidity. Theoretical calculations are compatible with the results obtained based on the neutron monitors and muon telescopes experimental data and confirm theoretically a unique dependence of the expected rigidity spectrum exponent ? of the Fd on the exponent ? of the PSD of the IMF turbulence.

Wawrzynczak, Anna; Alania, Michael V.

2010-05-01

300

Modeling and Experimental Study of Forbush Effects of Galactic Cosmic Rays  

NASA Astrophysics Data System (ADS)

temporal changes of the rigidity spectrum of the sporadic and recurrent Forbush effects of galactic cosmic rays (GCR) have been studied using neutron monitors data. An attempt to find a relationship between the rigidity spectrum exponent ? of the Forbush effects (?D/D(R) ? R-? , where R is the rigidity of GCR particles) and an exponent ? of the power spectral density (PSD) of the fluctuations of the strength of the interplanetary magnetic field (IMF) (PSD ? f-? , where f is the frequency) has been made. EXPERIMENTAL DATA AND METHOD OF INVESTIGATION. An attempt to find a relationship between the rigidity spectrum exponent ? of the Forbush effects [1] (? D/D(R) ? R-? , where R is the rigidity of GCR particles) and an exponent ? of the PSD of the fluctuations of the strength of the IMF has been made. Data of neutron super monitors and the IMF's Bx , By , and Bz components have been used to study peculiarities of two great sporadic Forbush effects (9-23 July 1982 and 9-29 July 2000) and one recurrent Forbush effect of the 1-16 September 1996 (figures 1ab c). It is well known that one of the ma jor parameters for the characterizing of the Forbush effects of GCR is the rigidity spectrum of the GCR intensity variations, hereafter called the rigidity spectrum of Forbush effect (? D(R)/D(R ) = A R-? , where R is the rigidity of GCR particles and A is the power). The rigidity spectrum of the Forbush effects has been calculated using the data of neutron super monitors and the method presented, e.g. in [2,3]. There was assumed: ? D(R)/D(R) = A R-? for R?Rmax . And ? D(R)/D(R) = 0 for R>Rmax. Here Rmax is the upper limiting rigidity beyond which the Forbush effect of GCR intensity vanishes. Results of calculations of ? based on daily means of data for the sporadic Forbush effects, 9-23 July 1982 (14 stations), 9-29 July 2000 (11 stations) and for the recurrent Forbush effect of 1-16 September 1996 (7 stations) are presented in the figures 1def. RESULTS, PHYSICAL MODEL AND DISCUSSION. It is seen from the fig.1de that the rigidity spectrum of the sporadic Forbush effects are soft at the phases of the decreasing of GCR intensity, while that

Alania, Michael V.; Szabelski, J.; Wawrzynczak, A.

2003-07-01

301

FLUKA Simulation of the Radiation Environment on the Surface of Mars  

E-print Network

only 0.03% of the GCR spectrum in terms of particle abundance, they are responsible for nearly 30% of the dose equivalent in free space. Because of this, radiation biology studies focusing on understanding the biological e ects of GCR exposure.... Stephen Guetersloh and my committee members Dr. Leslie Braby, Dr. John Ford, and Dr. John Lawler. I am thankful for their e orts. This work was supported by the U.S. Nuclear Regulatory Commission, Faculty Development Program, grant number NRC-38...

Northum, Jeremy

2013-07-10

302

Issues in deep space radiation protection  

NASA Technical Reports Server (NTRS)

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.

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

303

An Improved Analytic Model for Microdosimeter Response  

NASA Technical Reports Server (NTRS)

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.

Shinn, Judy L.; Wilson, John W.; Xapsos, Michael A.

2001-01-01

304

Badhwar-O'Neill 2011 Galactic Cosmic Ray Model Update and Future Improvements  

NASA Technical Reports Server (NTRS)

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.

O'Neill, Pat M.; Kim, Myung-Hee Y.

2014-01-01

305

The Projection of Space Radiation Environments with a Solar Cycle Statistical Model  

NASA Technical Reports Server (NTRS)

A solar cycle statistical model has been developed to project sunspot numbers which represent the variations in the space radiation environment. The resultant projection of sunspot numbers in near future were coupled to space-related quantities of interest in radiation protection, such as the galactic cosmic radiation (GCR) deceleration potential (f) and the mean occurrence frequency of solar particle event (SPE). Future GCR fluxes have been derived from a predictive model, in which GCR temporal dependence represented by f was derived from GCR flux and ground-based Climax neutron monitor rate measurements over the last four decades. Results showed that the point dose equivalent inside a typical spacecraft in interplanetary radiation fields was influenced by solar modulation up to a factor of three. One important characteristic of sporadic SPEs is their mean frequency of occurrence, which is dependent on solar activity. Projections of future mean frequency of SPE occurrence were estimated from a power law function of sunspot number. Furthermore, the cumulative probabilities of SPE during short-period missions were defined with the continuous database of proton fluences of SPE. The analytic representation of energy spectra of SPE was constructed by the Weibull distribution for different event sizes. The representative exposure level at each event size was estimated for the guideline of protection systems for astronauts during future space exploration missions.

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

2006-01-01

306

Pathologic role of stressed-induced glucocorticoids in drug-induced liver injury in mice  

Microsoft Academic Search

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,

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

2010-01-01

307

Lunar soil as shielding against space radiation  

Microsoft Academic Search

We have measured the radiation transport and dose reduction properties of lunar soil with respect to selected heavy ion beams with charges and energies comparable to some components of the galactic cosmic radiation (GCR), using soil samples returned by the Apollo missions and several types of synthetic soil glasses and lunar soil simulants. The suitability for shielding studies of synthetic

J. Miller; L. Taylor; C. Zeitlin; L. Heilbronn; S. Guetersloh; M. DiGiuseppe; Y. Iwata; T. Murakami

2009-01-01

308

Radiation Transmission Properties of In-Situ Materials  

Microsoft Academic Search

Exposure to Galactic Cosmic Radiation (GCR) and Solar Particle Events (SPE) is an inherent risk to human personnel working in Earth orbit and in deep-space missions. Future NASA manned missions, such as the construction and manning of the Space Station, the mission to Mars, and the return to the moon, will require longer duration stays in space, which in turn

Lawrence H. Heilbronn

309

Sex differences in operant responding and survivability following exposure to space radiation  

Technology Transfer Automated Retrieval System (TEKTRAN)

On exploratory class missions, such as a mission to Mars, astronauts will be exposed to types and doses of radiation (galactic cosmic rays [GCR]) which are not experienced in low earth orbit where the space shuttle and International Space Station operate. Despite the fact that the crew on such a mi...

310

Models for the Radiation Environment of Planet Mars and of Its Moon Phobos  

Microsoft Academic Search

Models of radiation environment induced by Galactic Cosmic Rays (GCR) and Solar Particle Events (SPE) on Mars and Phobos have been developed, as well as for the mission cruise phase, and used for the Liulin-Phobos experiment onboard the Phobos-Soil mission.

G. de Angelis; Ts. P. Dachev; J. V. Semkova; S. Maltchev; B. Tomov; Yu. Matviichuk; R. Koleva; V. Benghin; I. Chernykh; V. Shurshakov; V. Petrov

2009-01-01

311

Dependence of the 27-Day Variation of Cosmic Rays on the Global Magnetic Field of the Sun  

E-print Network

We show that the higher range of the heliolongitudinal asymmetry of the solar wind speed in the positive polarity period (Apos) than in the negative polarity period (Aneg) is one of the important reasons of the larger amplitudes of the 27-day variation of the galactic cosmic ray (GCR) intensity in the period of 1995-1997 (Apos) than in 1985-1987 (Aneg). Subsequently, different ranges of the heliolongitudinal asymmetry of the solar wind speed jointly with equally important corresponding drift effect are general causes of the polarity dependence of the amplitudes of the 27-day variation of the GCR intensity. At the same time, we show that the polarity dependence is feeble for the last unusual minimum epoch of solar activity 2007-2009 (Aneg); the amplitude of the 27-day variation of the GCR intensity shows only a tendency of the polarity dependence. We present a three dimensional (3-D) model of the 27-day variation of GCR based on the Parkers transport equation. In the 3-D model is implemented a longitudinal var...

Modzelewska, R

2015-01-01

312

Adv. Space Res. Vol. 14, No. 10, pp. (10)863-(10)871, 1994 1994 COSPAR  

E-print Network

Britain. All tights reserved. 0273-1177/94 $7.00 + 0.00 GALACTIC COSMIC RAY RADIATION LEVELS IN SPACECRAFT and Control, Inc., Hampton, VA 23669, U.S.A. ABSTRACT Using the Langley Research Center galactic cosmic ray, the cumulative exposure to the low level, high-LET (linear energy transfer) components of GCR poses a challenge

Shepherd, Simon

313

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

NASA Astrophysics Data System (ADS)

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.

Munakata, Kazuoki

2012-07-01

314

Mars surface radiation exposure for solar maximum conditions and 1989 solar proton events  

NASA Technical Reports Server (NTRS)

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.

Simonsen, Lisa C.; Nealy, John E.

1992-01-01

315

G-Protein Complex Mutants Are Hypersensitive to Abscisic Acid Regulation of Germination  

E-print Network

G-Protein Complex Mutants Are Hypersensitive to Abscisic Acid Regulation of Germination throughout plant growth and development. Seed germination, early seedling development, stomatal guard cell), and the candidate G-protein-coupled receptor (GCR1) in ABA signaling during germination and early seedling

Jones, Alan M.

316

How Safe Is Safe Enough? Radiation Risk for a Human Mission to Mars  

PubMed Central

Astronauts on a mission to Mars would be exposed for up to 3 years to galactic cosmic rays (GCR) — made up of high-energy protons and high charge (Z) and energy (E) (HZE) nuclei. GCR exposure rate increases about three times as spacecraft venture out of Earth orbit into deep space where protection of the Earth's magnetosphere and solid body are lost. NASA's radiation standard limits astronaut exposures to a 3% risk of exposure induced death (REID) at the upper 95% confidence interval (CI) of the risk estimate. Fatal cancer risk has been considered the dominant risk for GCR, however recent epidemiological analysis of radiation risks for circulatory diseases allow for predictions of REID for circulatory diseases to be included with cancer risk predictions for space missions. Using NASA's models of risks and uncertainties, we predicted that central estimates for radiation induced mortality and morbidity could exceed 5% and 10% with upper 95% CI near 10% and 20%, respectively for a Mars mission. Additional risks to the central nervous system (CNS) and qualitative differences in the biological effects of GCR compared to terrestrial radiation may significantly increase these estimates, and will require new knowledge to evaluate. PMID:24146746

Cucinotta, Francis A.; Kim, Myung-Hee Y.; Chappell, Lori J.; Huff, Janice L.

2013-01-01

317

How safe is safe enough? Radiation risk for a human mission to Mars.  

PubMed

Astronauts on a mission to Mars would be exposed for up to 3 years to galactic cosmic rays (GCR)--made up of high-energy protons and high charge (Z) and energy (E) (HZE) nuclei. GCR exposure rate increases about three times as spacecraft venture out of Earth orbit into deep space where protection of the Earth's magnetosphere and solid body are lost. NASA's radiation standard limits astronaut exposures to a 3% risk of exposure induced death (REID) at the upper 95% confidence interval (CI) of the risk estimate. Fatal cancer risk has been considered the dominant risk for GCR, however recent epidemiological analysis of radiation risks for circulatory diseases allow for predictions of REID for circulatory diseases to be included with cancer risk predictions for space missions. Using NASA's models of risks and uncertainties, we predicted that central estimates for radiation induced mortality and morbidity could exceed 5% and 10% with upper 95% CI near 10% and 20%, respectively for a Mars mission. Additional risks to the central nervous system (CNS) and qualitative differences in the biological effects of GCR compared to terrestrial radiation may significantly increase these estimates, and will require new knowledge to evaluate. PMID:24146746

Cucinotta, Francis A; Kim, Myung-Hee Y; Chappell, Lori J; Huff, Janice L

2013-01-01

318

Mars surface radiation exposure for solar maximum conditions and 1989 solar proton events  

NASA Astrophysics Data System (ADS)

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.

Simonsen, Lisa C.; Nealy, John E.

1992-02-01

319

On the influence of cosmic rays on the earth ozone layer as observed by microwave radiometry  

Microsoft Academic Search

The significant fluctuation of ozone content under altitude h>20 km above sea level has been connected with the atmosphere dynamics, and particularly with the stratospheric warmings and with internal gravitational waves. The galactic cosmic rays (GCR) are considered as the main reason of the ionization of atmospheric gas constituents. Among different methods of stratospheric ozone measurements, microwave radiometry observations make

A. G. Kislyakov; Yu. Yu. Kulikov

2004-01-01

320

GUIDELINES FOR DETERMINATION OF LABORATORY ACCEPTABILITY FOR ANALYSIS OF VOLATILE ORGANIC POLLUTANTS COLLECTED ON TENAX GC (TRADE NAME) ADSORBENT  

EPA Science Inventory

A Technical Assistant Document (TAD) has been prepared which is intended to serve as a guide to those persons responsible for evaluating and/or selecting a laboratory to perform sampling and analysis of airborne, organic pollutants using Tenax GCR polymer and gas chromatography/m...

321

This content has been downloaded from IOPscience. Please scroll down to see the full text. Download details  

E-print Network

polarities are, however, associated with a 40­60% difference in observed UK lightning and thunder rates lightning and thunder rates, possibly via lower energy solar particles compensating for the GCR decrease [26 and conditions apply. Modulation of UK lightning by heliospheric magnetic field polarity View the table

Lockwood, Mike

322

MCNP6 Cosmic-Source Option  

Microsoft Academic Search

MCNP is a Monte Carlo radiation transport code that has been under development for over half a century. Over the last decade, the development team of a high-energy offshoot of MCNP, called MCNPX, has implemented several physics and algorithm improvements important for modeling galactic cosmic-ray (GCR) interactions with matter. In this presentation, we discuss the latest of these improvements, a

Gregg W McKinney; Hirotatsu Armstrong; Michael R James; John Clem; Paul Goldhagen

2012-01-01

323

What can we learn on germinal centre reactions from in silico experiments?  

E-print Network

and further differentiate to plasma and memory cells (Kosco-Vilbois 2003). GCR in that way give rise to memory: Implications of the seeder cell quality for the GC development are to be clarified. The mechanisms leading centrocytes either re-proliferate or further differentiate to plasma and memory cells. All parameters

Meyer-Hermann, Michael

324

Computational trigonometry  

SciTech Connect

By means of the author`s earlier theory of antieigenvalues and antieigenvectors, a new computational approach to iterative methods is presented. This enables an explicit trigonometric understanding of iterative convergence and provides new insights into the sharpness of error bounds. Direct applications to Gradient descent, Conjugate gradient, GCR(k), Orthomin, CGN, GMRES, CGS, and other matrix iterative schemes will be given.

Gustafson, K. [Univ. of Colorado, Boulder, CO (United States)

1994-12-31

325

Managing Lunar and Mars Mission Radiation Risks. Part 1; Cancer Risks, Uncertainties, and Shielding Effectiveness  

NASA Technical Reports Server (NTRS)

This document addresses calculations of probability distribution functions (PDFs) representing uncertainties in projecting fatal cancer risk from galactic cosmic rays (GCR) and solar particle events (SPEs). PDFs are used to test the effectiveness of potential radiation shielding approaches. Monte-Carlo techniques are used to propagate uncertainties in risk coefficients determined from epidemiology data, dose and dose-rate reduction factors, quality factors, and physics models of radiation environments. Competing mortality risks and functional correlations in radiation quality factor uncertainties are treated in the calculations. The cancer risk uncertainty is about four-fold for lunar and Mars mission risk projections. For short-stay lunar missins (<180 d), SPEs present the most significant risk, but one effectively mitigated by shielding. For long-duration (>180 d) lunar or Mars missions, GCR risks may exceed radiation risk limits. While shielding materials are marginally effective in reducing GCR cancer risks because of the penetrating nature of GCR and secondary radiation produced in tissue by relativisitc particles, polyethylene or carbon composite shielding cannot be shown to significantly reduce risk compared to aluminum shielding. Therefore, improving our knowledge of space radiobiology to narrow uncertainties that lead to wide PDFs is the best approach to ensure radiation protection goals are met for space exploration.

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

2005-01-01

326

Designing a Complex Fragmentation Block for Simulating the Galactic Environment by Using a Single Accelerator Beam in PHITS (Practicle and Heavy Ion Transport Code System)  

E-print Network

the linear energy transfer (LET) spectrum found in the GCR. The purpose of this thesis research is to use a Monte Carlo transport code to study the fragmentation of a combined iron and proton beam source using a multi-depth moderator block to reproduce...

Chen, Gary

2011-10-21

327

Cosmic Ray Acceleration and Non-thermal X-rays in Cyg OB2  

Microsoft Academic Search

The astrophysical sites where Galactic cosmic ray (GCR) nuclei gain their extreme energies continue to defy indentification. It has been argued that the interacting, supersonic winds blowing from the many massive stars in young stellar associations - together with any SNRs therein - will set up shocks whose scale, power and duration could accelerate particles to CR energies. Thus, the

Yousaf Butt

2003-01-01

328

The production of cosmogenic nuclides in stony meteoroids by galactic cosmic ray particles  

Microsoft Academic Search

We present a purely physical model for the calculation of depth- and size-dependent production rates of cosmogenic nuclides by galactic cosmic ray particles. Besides the spectra of primary and secondary particles and the excitation functions of the underlying nuclear reactions the model is based on only one free parameter, the integral number of GCR particles in the meteoroid orbits. We

Ingo Leya; Hans-Jürgen Lange; Sonja Neumann; Rainer Wieler; Rolf Michel

2000-01-01

329

The proposed connection between clouds and cosmic rays: Cloud  

E-print Network

The proposed connection between clouds and cosmic rays: Cloud behaviour during the past 50 of galactic cosmic rays (GCR) and cloudiness. Here we review the evidence for such a connection from studies for the low cloud decrease predicted by the rising levels of solar activity and the low cloud­cosmic ray flux

330

Sudden cosmic ray decreases: No change of global cloud cover J. Calogovic,1  

E-print Network

Click Here for Full Article Sudden cosmic ray decreases: No change of global cloud cover J; revised 22 December 2009; accepted 4 January 2010; published 3 February 2010. [1] Currently a cosmic ray that galactic cosmic rays (GCR) intruding the Earth's atmosphere influence cloud cover. If correct it would have

Wehrli, Bernhard

331

CHEMICAL TECHNOLOGY DIVISION, UNIT OPERATIONS SECTION MONTHLY PROGRESS REPORT FOR FEBRUARY 1960  

Microsoft Academic Search

Vibratory compaction using air-operated piston type vibrators with ; accelerations up to 150 gees and frequencies up to 85 cycles\\/sec produced ; densities up to 8.2 g\\/cc. A test facility is being installed to study helium ; coolant purification for the GCR. Thorium dioxide particle size obtained by ; flame preparation appears to be Ilinited by particle division within the

M. E. Whatley; P. A. Haas; R. W. Horton; A. D. Ryon; J. C. Suddath; C. D. Watson

1960-01-01

332

Human follicular dendritic cells: function, origin and development  

Microsoft Academic Search

Follicular dendritic cells (FDCs) have important functions in the selection of memory B lymphocytes during germinal center reactions (GCR). They present native antigens to potential memory cells, of which only B cells with high affinity B cell receptors (BCR) can bind. These B lymphocytes survive, whereas nonbinding B cells undergo apoptotic cell death. FDCs are present in follicles of any

Kirsten van Nierop; Cornelis de Groot

2002-01-01

333

Radiation Dose Analysis of Galactic Cosmic Ray in Low Earth Orbit/Near Equatorial Orbit  

NASA Astrophysics Data System (ADS)

Space environment contained harmful radiation that posed risk to spacecraft orbiting the Earth. In this paper, we looked into radiation doses caused by galactic cosmic ray (GCR) towards satellites orbiting in low earth orbit (LEO) near Earth's equator (NEqO) and compared them with doses caused by solar energetic particles (SEP) and trapped particles to determine the damage level of GCR. The radiation doses included linear energy transfer (LET) and nonionizing energy loss (NIEL) through a 1mm gallium arsenide (GaAs) planar geometry by using Space Environment Information System (SPENVIS) method. The orbital data followed Malaysian Razaksat satellite at 685km altitude and 9° inclination during selected solar minimum and solar maximum from solar cycles 21 to 24. We found that trapped particles gave the highest LET and no SEP was detected in SPENVIS. The LET values tend to be higher during solar minimum for trapped particles and GCR, corresponding to their anti-correlated fluxes with the solar activity. However, the NIEL values for GCR in solar cycle 23 did not follow the anti-correlation pattern.

Suparta, W.; Zulkeple, S. K.

2014-10-01

334

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

Microsoft Academic Search

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

Marco Durante

2006-01-01

335

National Institute of Standards and Technology Technology Administration U.S. Department of Commerce February 2007  

E-print Network

With Applications in Packaging, Metals Recycling, Energy, and Water Treatment GCR 06-897 Thomas Pelsoci A Benefit with Applications in Packaging, Metals Recycling, Energy, and Water Treatment A Benefit-Cost Analysis Prepared (innovation in products, processes, and services from ATP supported projects) · Impacts (long term impacts

336

Cosmic Ray 11-Year Modulation for Sunspot Cycle 24  

NASA Astrophysics Data System (ADS)

Galactic cosmic-ray (GCR) modulation at 1 AU for sunspot (SSN) Cycle 24 is studied using data from a global network of detectors and balloon measurements of low-energy ions at high latitudes in Russia. The observed modulation is modest compared with previous cycles. The tilt angle of the heliospheric current sheet reached a maximum value for Cycle 24 even though the peak of the interplanetary magnetic-field intensity at 1 AU has a much lower value (? 5 nT). The solar polar field in the northern hemisphere reversed in June 2012 and again in March 2014 while that in the southern hemisphere reversed in July 2013. The double field reversal in northern hemisphere after SSN maximum is not expected from dynamo theory. GCR modulation is at maximum phase in 2013. We have also studied the anomalous GCR recovery in 2009 using data from a low-energy proton channel on Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA). The rigidity dependence of the Cycle 24 modulation is computed using data from neutron monitors, directional muon telescopes at Nagoya, Japan, and detectors on balloons at high latitudes in Russia. It is a power law with an exponent -1.29, similar to previous solar cycles (-1.2±0.1); the nearly linear dependence of the modulation on the rigidity over a wide range poses a challenge to the quasi-linear theory (QLT) of GCR modulation.

Ahluwalia, H. S.; Ygbuhay, R. C.

2015-02-01

337

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

PubMed Central

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

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

338

Custom Device for Low-Dose Gamma Irradiation of Biological Samples  

E-print Network

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...

Bi, Ruoming

2012-02-14

339

Comparison of CREME (cosmic-ray effects on microelectronics) model LET (linear energy transfer) spaceflight dosimetry data  

SciTech Connect

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.

Letaw, J.R.; Adams, J.H.

1986-07-15

340

The Average Quality Factors by TEPC for Charged Particles  

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

341

A field assessment of long-term laboratory sediment toxicity tests with the amphipod Hyalella azteca  

USGS Publications Warehouse

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.

Ingersoll, C.G.; Wang, N.; Hayward, J.M.R.; Jones, J.R.; Jones, S.B.; Ireland, D.S.

2005-01-01

342

Simulation and Comparison of Martian Surface Ionization Radiation  

NASA Astrophysics Data System (ADS)

The spectrum of energetic particle radiation and corresponding doses at the surface of Mars is being characterized by the Radiation Assessment Detector (RAD), one of ten science instruments on the Mars Science Laboratory (MSL) Curiosity Rover. The time series of dose rate for the first 300 Sols after landing on Mars on August 6, 2012 is presented here. For the comparison to RAD measurements of dose rate, Martian surface ionization radiation is simulated by utilizing observed space quantities. The GCR primary radiation spectrum is calculated by using the Badhwar-O'Neill 2011 (BO11) galactic cosmic ray (GCR) model, which has been developed by utilizing all balloon and satellite GCR measurements since 1955 and the newer 1997-2012 Advanced Composition Explorer (ACE) measurements. In the BO11 model, solar modulation of the GCR primary radiation spectrum is described in terms of the international smoothed sunspot number and a time delay function. For the transport of the impingent GCR primary radiation through Mars atmosphere, a vertical distribution of atmospheric thickness at each elevation is calculated using the vertical profiles of atmospheric temperature and pressure made by Mars Global Surveyor measurements. At Gale Crater in the southern hemisphere, the seasonal variation of atmospheric thickness is accounted for the daily atmospheric pressure measurements of the MSL Rover Environmental Monitoring Station (REMS) by using low- and high-density models for cool- and warm-season, respectively. The spherically distributed atmospheric distance is traced along the slant path, and the resultant directional shielding by Martian atmosphere is coupled with Curiosity vehicle for dose estimates. We present predictions of dose rate and comparison to the RAD measurements. The simulation agrees to within +-20% with the RAD measurements showing clearly the variation of dose rate by heliospheric conditions, and presenting the sensitivity of dose rate by atmospheric pressure, which has been found from the RAD experiments and driven by thermal tides on Martian surface.

Kim, M. Y.; Zeitlin, C. J.; Hassler, D.; Cucinotta, F.

2013-12-01

343

Large Galactic Cosmic Ray Anisotropies in the Heliosheath  

NASA Astrophysics Data System (ADS)

The angular distribution of galactic cosmic ray (GCR) intensities had been observed to be nearly isotropic throughout the space age, with even the largest anisotropies falling well short of 1%. Voyager 1, after the initial GCR intensity enhancement in May 2012 and upon sustainably entering a region depleted of hot plasma on 25 August 2012 (Burlaga et al. 2013; Krimigis et al. 2013; Stone et al. 2013; Webber & McDonald 2013), has uncovered a new regime where large GCR anisotropies prevail. We recently reported on the largest GCR anisotropies observed (Krimigis et al., 2013; Hill et al., 2013), with the second order anisotropy of >200 MeV GCRs reaching ~3.5%. We developed a new technique to extract bi-directional intensities from a double-ended particle telescope that has asymmetric viewing geometry (i.e., the geometric factor for particle detection with one end is unequal to the geometric factor of the other end). Applying this technique we report here on the variation of GCR anisotropies at Voyager 1 and 2 in the depletion region, in the hot heliosheath, and upstream of the termination shock. Burlaga, L.F. et al, 2013, Science 341, 147-150, DOI: 10.1126/science.1235451. Hill, M.E. et al, 2013, presented at the 12th Ann. Inter. Astrophys. Conf., Myrtle Beach, SC, 15-19 April 2013. Krimigis, S.M. et al., 2013, Science 341, 144-147, DOI: 10.1126/science.1235721. Stone, E.C. et al., 2013, Science 341, 150-153, DOI: 10.1126/science.1236408. Webber & McDonald, 2013, Geophys. Res. Let. 40, 1665-1668, DOI: 10.1002/grl.50383.

Hill, M. E.; Decker, R. B.; Hamilton, D. C.; Brown, L. E.; Krimigis, S. M.; Roelof, E. C.

2013-12-01

344

Assessing the experience in complex hepatopancreatobiliary surgery among graduating chief residents: Is the operative experience enough?  

PubMed Central

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

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

345

An Analytical Model for the Prediction of a Micro-Dosimeter Response Function  

NASA Technical Reports Server (NTRS)

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.

Badavi, Francis F.; Xapsos, Mike

2008-01-01

346

Validity of the Aluminum Equivalent Approximation in Space Radiation Shielding  

NASA Technical Reports Server (NTRS)

The origin of the aluminum equivalent shield approximation in space radiation analysis can be traced back to its roots in the early years of the NASA space programs (Mercury, Gemini and Apollo) wherein the primary radiobiological concern was the intense sources of ionizing radiation causing short term effects which was thought to jeopardize the safety of the crew and hence the mission. Herein, it is shown that the aluminum equivalent shield approximation, although reasonably well suited for that time period and to the application for which it was developed, is of questionable usefulness to the radiobiological concerns of routine space operations of the 21 st century which will include long stays onboard the International Space Station (ISS) and perhaps the moon. This is especially true for a risk based protection system, as appears imminent for deep space exploration where the long-term effects of Galactic Cosmic Ray (GCR) exposure is of primary concern. The present analysis demonstrates that sufficiently large errors in the interior particle environment of a spacecraft result from the use of the aluminum equivalent approximation, and such approximations should be avoided in future astronaut risk estimates. In this study, the aluminum equivalent approximation is evaluated as a means for estimating the particle environment within a spacecraft structure induced by the GCR radiation field. For comparison, the two extremes of the GCR environment, the 1977 solar minimum and the 2001 solar maximum, are considered. These environments are coupled to the Langley Research Center (LaRC) deterministic ionized particle transport code High charge (Z) and Energy TRaNsport (HZETRN), which propagates the GCR spectra for elements with charges (Z) in the range I <= Z <= 28 (H -- Ni) and secondary neutrons through selected target materials. The coupling of the GCR extremes to HZETRN allows for the examination of the induced environment within the interior' of an idealized spacecraft as approximated by a spherical shell shield, and the effects of the aluminum equivalent approximation for a good polymeric shield material such as genetic polyethylene (PE). The shield thickness is represented by a 25 g/cm spherical shell. Although one could imagine the progression to greater thickness, the current range will be sufficient to evaluate the qualitative usefulness of the aluminum equivalent approximation. Upon establishing the inaccuracies of the aluminum equivalent approximation through numerical simulations of the GCR radiation field attenuation for PE and aluminum equivalent PE spherical shells, we Anther present results for a limited set of commercially available, hydrogen rich, multifunctional polymeric constituents to assess the effect of the aluminum equivalent approximation on their radiation attenuation response as compared to the generic PE.

Badavi, Francis F.; Adams, Daniel O.; Wilson, John W.

2009-01-01

347

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

NASA Technical Reports Server (NTRS)

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.

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

348

Time-dependent radiation hazard estimations during space flights  

NASA Astrophysics Data System (ADS)

Cosmic particle radiation is a limiting factor for the out of magnetosphere crewed flights. The cosmic radiation uncrewed flights inside heliosphere and crewed flights inside of magnetosphere tend to become a routine procedure, whereas there have been only few shot time flights out of it (Apollo missions 1969-1972) with maximum duration less than a month. Long term crewed missions set much higher requirements to the radiation shielding, primarily because of long exposition term. Inside the helosphere there are two main sources of cosmic radiation: galactic cosmic rays (GCR) and coronal mass ejections (CME). GCR come from the outside of heliosphere forming a background of overall radiation that affects the spacecraft. The intensity of GCR is varied according to solar activity, increasing with solar activity decrease and backward, with the modulation time (time between nearest maxima) of 11 yeas. CME are shot term events, comparing to GCR modulation time, but are much more energetic. The probability of CME increases with the increase of solar activity. Time dependences of the intensity of these two components encourage looking for a time window of flight, when intensity and affection of CME and GCR would be minimized. Applying time dependent models of GCR spectra [1] and estimations of CME we show the time dependence of the radiation dose in a realistic human phantom [2] inside the shielding capsule. We pay attention to the shielding capsule design, looking for an optimal geometry parameters and materials. Different types of particles affect differently on the human providing more or less harm to the tissues. Incident particles provide a large amount of secondary particles while propagating through the shielding capsule. We make an attempt to find an optimal combination of shielding capsule parameters, namely material and thickness, that will effectively decrease the incident particle energy, at the same time minimizing flow of secondary induced particles and minimizing most harmful particle types flows. 1.Nymmik et. al., “Galactic cosmic ray flux simulation and prediction”, Adv. Space Res. 17:19-30, (1996); 2. Xu et. al., “VIP-Man: an image-based whole-body adult male model constructed from color photographs of the Visible Human Project for multi-particle Monte Carlo calculations” Health Phys. 78:476-86, (2000).

Dobynde, Mikhail; Shprits, Yuri; Drozdov, Alexander

349

Radiation Physics for Space and High Altitude Air Travel  

NASA Technical Reports Server (NTRS)

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.

Cucinotta, F. A.; Wilson, J. W.; Goldhagen, P.; Saganti, P.; Shavers, M. R.; McKay, Gordon A. (Technical Monitor)

2000-01-01

350

Measurement of the Relative Abundances of the Ultra-Heavy Galactic Cosmic-Ray Abundances (30 ? Z ? 40) with TIGER  

NASA Astrophysics Data System (ADS)

Observations of Ultra-Heavy galactic cosmic rays (GCR) help to distinguish the possible origins of GCRs. The Trans-Iron Galactic Recorder (TIGER) is designed to measure the charge (Z) and energy of GCRs using a combination of scintillation counters, Cherenkov counters, and a scintillating fiber hodoscope. TIGER has accumulated data on two successful flights from McMurdo, Antarctica: the first launched in December of 2001 with a total flight duration of 31.8 days and the second in December of 2003 with a total flight duration of 18 days. The two flights of TIGER achieved sufficient statistics and charge resolution to resolve ~140 particles with Z > 30, and have provided the best measurements to date for Zn, Ga, Ge, and Se. We present a preliminary analysis of the combined data from both flights for Ultra-Heavy GCRs and discuss the results in the context of different GCR source models.

Rauch, B. F.; Barbier, L. M.; Binns, W. R.; Cummings, J. R.; de Nolfo, G. A.; Geier, S.; Israel, M. H.; Link, J. T.; Mewaldt, R. A.; Mitchell, J. W.; Schindler, S. M.; Scott, L. M.; Stone, E. C.; Streitmatter, R. E.; Waddington, C. J.

2007-11-01

351

Measurement of the Relative Abundances of the Ultra-Heavy Galactic Cosmic Rays (30 <=Z <=40) at the Top of the Atmosphere with TIGER  

NASA Astrophysics Data System (ADS)

Observations of Ultra-Heavy galactic cosmic rays (GCR) help to distinguish the possible origins of GCRs. The Trans-Iron Galactic Element Recorder (TIGER) is designed to measure the charge (Z) and energy of GCRs using a combination of scintillation counters, Cherenkov counters, and a scintillating fiber hodoscope. TIGER has accumulated data on two successful flights from McMurdo, Antarctica in December of 2001 and in December of 2003 with a total flight duration of ˜50 days. The combined TIGER dataset achieved sufficient statistics and charge resolution to resolve ˜140 particle with Z>30, and provides the measurements to date for 30Zn, 31Ga, 32Ge, and 34Se. We present the preliminary abundances of the Ultra-Heavy GCRs derived from the combined dataset propagated to the top of the atmosphere, and discuss the results in the context of previous measurements and different GCR source models.

Rauch, B. F.; Binns, W. R.; Israel, M. H.; Link, J. T.; Scott, L. M.; Barbier, L. M.; Cummings, J. R.; de Nolfo, G. A.; Mitchell, J. W.; Streitmatter, R. E.; Geier, S.; Mewaldt, R. A.; Schindler, S. M.; Stone, E. C.; Waddington, C. J.

2007-04-01

352

Numerical Study of the Generation of Linear Energy Transfer Spectra for Space Radiation Applications  

NASA Technical Reports Server (NTRS)

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.

Badavi, Francis F.; Wilson, John W.; Hunter, Abigail

2005-01-01

353

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

E-print Network

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...

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

354

Space Radiation and Exploration - Information for the Augustine Committee Review  

NASA Technical Reports Server (NTRS)

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).

Cucinotta, Francis; Semones, Edward; Kim, Myung-Hee; Jackson, Lori

2009-01-01

355

MARIE: Current Status and Results from 20 Months of Observations at Mars  

NASA Technical Reports Server (NTRS)

The MARIE instrument aboard the 2001 Mars Odyssey spacecraft detects energetic charged particles in the Galactic Cosmic Radiation (GCR) and during solar particle events (SPE) [1]. As of this writing (January 2004), MARIE has been turned off, after losing communication with the spacecraft during the large SPE of October 28, 2003. However, during the prior 20 months, MARIE collected data almost continuously, observing several solar events and the nearly-constant GCR. There is still a possibility the instrument can be recovered, and troubleshooting efforts are scheduled to begin in May 2004, following the completion of the primary missions of MER-A (Spirit) and MER-B (Opportunity). At present, Odyssey is acting as a telecommunications relay for the rovers and only routine science operations are permitted in this mode.

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

2004-01-01

356

Results from the Martian Radiation Environment Experiment MARIE  

NASA Technical Reports Server (NTRS)

One of the three science instruments aboard the 2001 Mars Odyssey spacecraft is the Martian Radiation Environment Experiment, MARIE. MARIE consists of a stack of silicon detectors, augmented by a Cerenkov detector. MARIE is designed to measure a portion of the particle spectrum of the Galactic Cosmic Rays (GCR), as well as the high fluxes of low-energy protons (energies less than about 100 MeV) that are intermittently produced by active regions on the sun in Solar Particle Events (SPE). MARIE is providing the first detailed information about the radiation environment near Mars.measurements. MARIE has been operating successfully for nearly a year. Solar particle events of considerable interest have been observed, and data have been obtained that will yield GCR spectra from a novel observation point in the solar system.

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

2003-01-01

357

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

PubMed Central

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

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

2014-01-01

358

Preliminary Design of a Galactic Cosmic Ray Shielding Materials Testbed for the International Space Station  

NASA Technical Reports Server (NTRS)

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.

Gaier, James R.; Berkebile, Stephen; Sechkar, Edward A.; Panko, Scott R.

2012-01-01

359

Light ion components of the galactic cosmic rays: Nuclear interactions and transport theory  

NASA Technical Reports Server (NTRS)

Light nuclei are present in the primary galactic cosmic rays (GCR) and are produced in thick targets due to projectile or target fragmentation from both nucleon and heavy induced reactions. In the primary GCR, He-4 is the most abundant nucleus after H-1. However, there are also a substantial fluxes of H-2 and He-3. In this paper we describe theoretical models based on quantum multiple scattering theory for the description of light ion nuclear interactions. The energy dependence of the light ion fragmentation cross section is considered with comparisons of inclusive yields and secondary momentum distributions to experiments described. We also analyze the importance of a fast component of lights ions from proton and neutron induced target fragementation. These theoretical models have been incorporated into the cosmic ray transport code HZETRN and will be used to analyze the role of shielding materials in modulating the production and the energy spectrum of light ions.

Cucinotta, F. A.; Townsend, L. W.; Wilson, J. W.; Shinn, J. L.; Badhwar, G. D.; Dubey, R. R.

1996-01-01

360

Solar cosmic ray produced neon in lunar soils and their implication for gas-rich meteorite studies  

NASA Technical Reports Server (NTRS)

Characteristic neon isotopic ratios, produced due to solar cosmic ray spallation (SCR) in lunar soils, are useful in deciphering and estimating the relative contributions of SCR and GCR spallation. To delineate these features, etched mineral grains from mature and immature lunar soils (14148 and 61221 respectively) were analyzed using mass spectrometry. The SF-Ne composition deduced in this work agrees with that obtained from earlier etched lunar pyroxene studies. The data points for mature soil 14148 define a line which significantly deviates from the 61221 tie line. This deviation is attributed to the presence of SCR spallation component. In this context, neon isotopic compositions (step-wise heating) in Pantar and Leighton dark portions were studied and compared with that of Fayetteville. The meteorite data points deviate significantly from the tie line joining SF-Ne and GCR (pyroxene) end points. This deviation is attributed to SCR-spallation in gas-rich chondrites.

Nautiyal, C. M.; Rao, M. N.

1984-01-01

361

Effects of radiobiological uncertainty on vehicle and habitat shield design for missions to the moon and Mars  

NASA Technical Reports Server (NTRS)

Some consequences of uncertainties in radiobiological risk due to galactic cosmic ray (GCR) exposure are analyzed for their effect on engineering designs for the first lunar outpost and a mission to explore Mars. This report presents the plausible effect of biological uncertainties, the design changes necessary to reduce the uncertainties to acceptable levels for a safe mission, and an evaluation of the mission redesign cost. Estimates of the amount of shield mass required to compensate for radiobiological uncertainty are given for a simplified vehicle and habitat. The additional amount of shield mass required to provide a safety factor for uncertainty compensation is calculated from the expected response to GCR exposure. The amount of shield mass greatly increases in the estimated range of biological uncertainty, thus, escalating the estimated cost of the mission. The estimates are used as a quantitative example for the cost-effectiveness of research in radiation biophysics and radiation physics.

Wilson, John W.; Nealy, John E.; Schimmerling, Walter; Cucinotta, Francis A.; Wood, James S.

1993-01-01

362

Solar modulation and nuclear fragmentation effects in galactic cosmic ray transport through shielding  

NASA Technical Reports Server (NTRS)

Crews of manned interplanetary missions may accumulate significant radiation exposures from the Galactic Cosmic Ray (GCR) environment in space. Estimates of how these dose levels are affected by the assumed temporal and spatial variations in the composition of the GCR environment, and by the effects of the spacecraft and body self-shielding on the transported fields are presented. In this work, the physical processes through which shielding alters the transported radiation fields are described. We then present estimates of the effects on model calculations of (1) nuclear fragmentation model uncertainties, (2) solar modulation, (3) variations between solar cycles, and (4) proposed changes to the quality factors which relate dose equivalent to absorbed dose.

Townsend, L. W.; Cucinotta, C. F.; Wilson, J. W.; Shinn, J. L.; Badhwar, G.

1994-01-01

363

Revisited modeling of Titan’s middle atmosphere electrical conductivity  

NASA Astrophysics Data System (ADS)

The atmospheric electrical conductivity measured by the Permittivity, Wave and Altimetry (PWA) subsystem on board the Huygens probe, during the landing mission on Titan, has been modeled in the present work. Previous modeling studies showed a Galactic Cosmic Ray (GCR) peak of conductivity at a higher altitude and a quantitative overestimation in the altitude range 0-100 km compared to that observed by the PWA instrument. Recently the PWA data was revisited and provided new constraints on the conductivity at altitudes 100-180 km. Because the aerosols in the atmosphere are known to alter the electron concentration, using a detailed distribution of the aerosols at all altitudes, the electron conductivity has been calculated in the altitude range 0-180 km. By using a variable range of photoemission threshold for the aerosols, the present model is able to reasonably predict the altitude at which the GCR peak of conductivity occurs and to meet the new constraints for the conductivity profile.

Mishra, Alabhya; Michael, Marykutty; Tripathi, Sachchida Nand; Béghin, Christian

2014-08-01

364

Interphases, gelation, vitrification, porous glasses and the generalized Cauchy relation: epoxy/silica nanocomposites  

NASA Astrophysics Data System (ADS)

The generalized Cauchy relation (gCR) of epoxy/silica nano-composites does not show either the chemically induced sol-gel transition or the chemically induced glass transition in the course of polymerization. Astonishingly, by varying the silica nanoparticles' concentration between 0 and 25 vol% in the composites, the Cauchy parameter A of the gCR remains universal and can be determined from the pure epoxy's elastic moduli. Air-filled porous silica glasses are considered as models for percolated silica particles. A longitudinal modulus versus density representation evidences the aforementioned transition phenomena during polymerization of the epoxy/silica nanocomposites. The existence of optically and mechanically relevant interphases is discussed.

Philipp, M.; Müller, U.; Jiménez Riobóo, R. J.; Baller, J.; Sanctuary, R.; Possart, W.; Krüger, J. K.

2009-02-01

365

Study - Radiation Shielding Effectiveness of the Prototyped High Temperature Superconductivity (HTS) 'Artificial' Magnetosphere for Deep Space Missions  

NASA Technical Reports Server (NTRS)

The high temperature superconductor (HTS) is being used to develop the magnets for the Variable Specific Impulse Magneto-plasma Rocket (VASIMR ) propulsion system and may provide lightweight magnetic radiation shielding to protect spacecraft crews from radiation caused by GCR and SPEs on missions to Mars. A study is being planned to assess the radiation shielding effectiveness of the artificial magnetosphere produced by the HTS magnet. VASIMR is an advanced technology propulsion engine which is being touted as enabling one way transit to Mars in 90 days or less. This is extremely important to NASA. This technology would enable a significant reduction in the number of days in transit to and from Mars and significantly reduce the astronauts exposure to a major threat - high energy particles from solar storms and GCR during long term deep space missions. This paper summarizes the plans for the study and the subsequent testing of the VASIMR technology onboard the ISS slated for 2013.

Denkins, Pamela

2010-01-01

366

Cosmic Ray Modulation in the Outer Heliosphere During the Minimum of Solar Cycle 23/24  

NASA Technical Reports Server (NTRS)

We report a next generation model of galactic cosmic ray (GCR) transport in the three dimensional heliosphere. Our model is based on an accurate three-dimensional representation of the heliospheric interface. This representation is obtained by taking into account the interaction between partially ionized, magnetized plasma flows of the solar wind and the local interstellar medium. Our model reveals that after entering the heliosphere GCRs are stored in the heliosheath for several years. The preferred GCR entry locations are near the nose of the heliopause and at high latitudes. Low-energy (hundreds of MeV) galactic ions observed in the heliosheath have spent, on average, a longer time in the solar wind than those observed in the inner heliosphere, which would explain their cooled-off spectra at these energies. We also discuss radial gradients in the heliosheath and the implications for future Voyager observations.

Adams, James H., Jr.; Florinski, V.; Washimi, H.; Pogorelov, N. V.

2011-01-01

367

Galactic Cosmic Rays in the Outer Heliosphere  

NASA Technical Reports Server (NTRS)

We report a next generation model of galactic cosmic ray (GCR) transport in the three dimensional heliosphere. Our model is based on an accurate three-dimensional representation of the heliospheric interface. This representation is obtained by taking into account the interaction between partially ionized, magnetized plasma flows of the solar wind and the local interstellar medium. Our model reveals that after entering the heliosphere GCRs are stored in the heliosheath for several years. The preferred GCR entry locations are near the nose of the heliopause and at high latitudes. Low-energy (hundreds of MeV) galactic ions observed in the heliosheath have spent, on average, a longer time in the solar wind than those observed in the inner heliosphere, which would explain their cooled-off spectra at these energies. We also discuss radial gradients in the heliosheath and the implications for future Voyager observations

Florinski, V.; Washimi, H.; Pogorelov, N. V.; Adams, J. H.

2010-01-01

368

Cosmic-ray record in solar system matter  

NASA Technical Reports Server (NTRS)

The interaction of galactic cosmic rays (GCR) and solar cosmic rays (SCR) with bodies in the solar system is discussed, and what the record of that interaction reveals about the history of the solar system is considered. The influence of the energy, charge, and mass of the particles on the interaction is addressed, showing long-term average fluxes of solar protons, predicted production rates for heavy-nuclei tracks and various radionuclides as a function of depth in lunar rock, and integral fluxes of protons emitted by solar flares. The variation of the earth's magnetic field, the gardening of the lunar surface, and the source of meteorites and cosmic dust are studied using the cosmic ray record. The time variation of GCR, SCR, and VH and VVH nuclei is discussed for both the short and the long term.

Reedy, R. C.; Arnold, J. R.; Lal, D.

1983-01-01

369

Long term variation of the solar diurnal anisotropy of galactic cosmic rays observed with the Nagoya multi-directional muon detector  

E-print Network

We analyze the three dimensional anisotropy of the galactic cosmic ray (GCR) intensities observed independently with a muon detector at Nagoya in Japan and neutron monitors over four solar activity cycles. We clearly see the phase of the free-space diurnal anisotropy shifting toward earlier hours around solar activity minima in A>0 epochs, due to the reduced anisotropy component parallel to the mean magnetic field. The average parallel component is consistent with a rigidity independent spectrum, while the perpendicular component increases with GCR rigidity. We suggest that this harder spectrum of the perpendicular component is due to contribution from the drift streaming. We find that the bidirectional latitudinal density gradient is positive in A>0 epoch, while it is negative in A0 and A0. We also find, however, that parallel mean free path (radial gradient) appears to persistently increase (decreasing) in the last three cycles of weakening solar activity. We suggest that simple differences between these pa...

Munakata, K; Kato, C; Kota, J

2014-01-01

370

Galactic cosmic ray abundances and spectra behind defined shielding.  

PubMed

LET spectra have been measured for lunar missions and for several near Earth orbits ranging from 28 degrees to 83 degrees inclination. In some of the experiments the flux of GCR was determined separately from contributions caused by interactions in the detector material. Results of these experiments are compared to model calculations. The general agreement justifies the use of the model to calculate GCR fluxes. The magnitude of variations caused by solar modulation, geomagnetic shielding, and shielding by matter determined from calculated LET spectra is generally in agreement with experimental data. However, more detailed investigations show that there are some weak points in modeling solar modulation and shielding by material. These points are discussed in more detail. PMID:11540030

Heinrich, W; Benton, E V; Wiegel, B; Zens, R; Rusch, G

1994-10-01

371

The Feasibility of Multipole Electrostatic Radiation Shielding  

NASA Technical Reports Server (NTRS)

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.

Metzger, Philip T.; Lane, John E.; Youngquist, Robert C.

2004-01-01

372

Matrix models and graph colouring  

NASA Astrophysics Data System (ADS)

We study an edge-colouring problem on random planar graphs which is one of the simplest vertex models that may be analyzed by standard methods of large N matrix models. The main features of the saddle point solution and its critical behaviour are described. At the critical value of the coupling gcr the eigen value density u(?)M is found to vanish at the border of the support as ?-a2/3.

Cicuta, Giovanni M.; Molinari, Luca; Montaldi, Emilio

1993-06-01

373

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

NASA Astrophysics Data System (ADS)

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.

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

2014-01-01

374

ISOLATED WOLF-RAYET STARS AND O SUPERGIANTS IN THE GALACTIC CENTER REGION IDENTIFIED VIA PASCHEN-{alpha} EXCESS  

SciTech Connect

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.

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

375

Multi-Scale Model of Galactic Cosmic Ray Effects on the Hippocampus  

NASA Astrophysics Data System (ADS)

An important concern for risk assessment from galactic cosmic ray (GCR) exposures is impacts to the central nervous systems including changes in cognition, and associations with increased risk of Alzheimer’s disease (AD). AD, which affects about 50 percent of the population above age 80-yr, is a degenerative disease that worsens with time after initial onset leading to death, and has no known cure. AD is difficult to detect at early stages, and the small number of epidemiology studies that have considered the possibility have not identified an association with low dose radiation. However, experimental studies in transgenic mice suggest the possibility exits. We discuss modeling approaches to consider mechanisms whereby GCR would accelerate the occurrence of AD to earlier ages. Biomarkers of AD include Amyloid beta plaques, and neurofibrillary tangles (NFT) made up of aggregates of the hyper-phosphorylated form of the micro-tubule associated, tau protein. Related markers include synaptic degeneration, dendritic spine loss, and neuronal cell loss through apoptosis. GCR may affect these processes by causing oxidative stress, aberrant signaling following DNA damage, and chronic neuro-inflammation. Cell types considered in multi-scale models are neurons, astrocytes, and microglia. We developed biochemical and cell kinetics models of DNA damage signaling related to glycogen synthase kinase-3 beta and neuro-inflammation, and considered approaches to develop computer simulations of GCR induced cell interactions and their relationships to Amyloid beta plaques and NFTs. Comparison of model results to experimental data for the age specific development of plaques in transgenic mice and predictions of space radiation effects will be discussed.

Cucinotta, Francis

376

PAHs in the Chinese environment: levels, inventory mass, source and toxic potency assessment.  

PubMed

This paper presents a systematic but preliminary study on the levels, inventory mass, emission sources and risk of exposure to PAHs in China by examining 14 polycyclic aromatic hydrocarbons (from the 16 priority PAHs listed by the U.S. EPA, excluding naphthalene and acenaphthylene) in four main environmental media (air, water, soil and sediment). The concentration of individual PAHs in the air, soil, freshwater, seawater, freshwater sediment and marine sediment of China was compared with the global concentration range (GCR) of PAHs from a large number of studies. The PAH levels were found at the high end of the GCR in the air, at the upper middle of the GCR in the water body, and at the middle of the GCR in the soil and sediment. These indicate that PAHs still are emitted heavily in China. About 530?000 tons of ?14PAH was estimated to be distributed into these four media in China. Soil possesses the highest proportion of the PAHs (60%), and the air has the lowest proportion (<0.5%). Therefore, the soil and sediment play an important role in the storage of PAHs. More than 10 thousand tons of PAHs are emitted from all kinds of sources. Firewood, straw, domestic and coking were considered as the main emissions of PAHs in the energy supply. A benzo[a]pyrene (BaP) based hazard quotient (HQ) was introduced to assess the potential toxic risk of exposure. The terrestrial water environment was found to have a high BaP exposure. The HQ value was more than 1 for 58% of freshwater and 39% of freshwater sediment samples. Urban and developed sites were considered to have high BaP exposure risk. PMID:23665869

Wang, Ji-Zhong; Zhu, Cheng-Zhu; Chen, Tian-Hu

2013-06-01

377

Minimizing Astronauts' Risk from Space Radiation during Future Lunar Missions  

NASA Technical Reports Server (NTRS)

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.

Kim, Myung-Hee Y.; Hayat, Mathew; Nounu, Hatem N.; Feiveson, Alan H.; Cucinotta, Francis A.

2007-01-01

378

Present situation of the operation and maintenance management of nuclear power plants in Japan - Aiming at further improved safety and reliability  

Microsoft Academic Search

In Japan, more than 28 years have passed since the first commercial nuclear power plant started operation, and now, as of September 1993, a total 45 plants with 37,196 MWe are in operation. (24 BWR plants\\/20,914 MWe; 20 PWR plants\\/16, 116 MWe and 1 GCR plant\\/166 MWe). After about 550 reactor - years of operating experience, as of July 1993,

T. Hattori; K. Imoto; K. Akutagawa

1994-01-01

379

Radiation risk predictions for Space Station Freedom orbits  

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

380

Polymeric Materials With Additives for Durability and Radiation Shielding in Space  

NASA Technical Reports Server (NTRS)

Polymeric materials are attractive for use in space structures because of their light weight and high strength In addition, polymers are made of elements with low atomic numbers (Z), primarily carbon (C), hydrogen (H), oxygen (0), and nitrogen (N) which provide the best shielding from galactic cosmic rays (GCR) (ref. 1). Galactic cosmic rays are composed primarily of nuclei (i.e., fully ionized atoms) plus a contribution of about 2% from electrons and positrons. There is a small but significant component of GCR particles with high charge (Z > 10) and high energy (E >100 GeV) (ref. 2). These so-called HZE particles comprise only 1 to 2% of the cosmic ray fluence but they interact with very high specific ionization and contribute 50% of the long- term dose to humans. The best shield for this radiation would be liquid hydrogen, which is not feasible. For this reason, hydrogen-containing polymers make the most effective practical shields. Moreover, neutrons are formed in the interactions of GCR particles with materials. Neutrons can only lose energy by collisions or reactions with a nucleus since they are uncharged. This is a process that is much less probable than the Coulombic interactions of charged particles. Thus, neutrons migrate far from the site of the reaction in which they were formed. This increases the probability of neutrons reaching humans or electronic equipment. Fast neutrons (> 1 MeV) can interact with silicon chips in electronic equipment resulting in the production of recoil ions which can cause single event upsets (SEU) in sensitive components (ref. 3). Neutrons lose energy most effectively by elastic collisions with light atoms, particularly hydrogen atoms. Therefore, hydrogen-containing polymers are not only effective in interacting with GCR particles; they are also effective in reducing the energy of the neutrons formed in the interactions.

Kiefer, Richard

2011-01-01

381

Radiation Measured with Different Dosimeters for ISS-Expedition 18-19/ULF2 on Board International Space Station during Solar Minimum  

NASA Technical Reports Server (NTRS)

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.

Zhou, Dazhuang; Gaza, R.; Roed, Y.; Semones, E.; Lee, K.; Steenburgh, R.; Johnson, S.; Flanders, J.; Zapp, N.

2010-01-01

382

Sunspot activity and cosmic ray modulation at 1 a.u. for 1900-2013  

NASA Astrophysics Data System (ADS)

The descent of sunspot cycle 23 to an unprecedented minimum of long duration in 2006-2009 led to a prolonged galactic cosmic ray (GCR) recovery to the highest level observed in the instrumental era for a variety of energetic charged particle species on Earth, over a wide range of rigidities. The remarkable GCR increase measured by several ground-based, balloon-borne, and detectors on a satellite is described and discussed. It is accompanied by a decrease in solar wind velocity and interplanetary magnetic field at 1 a.u., reaching the lowest values since measurements of the solar wind began in October 1963; the solar polar field strength (?T) measured at the Wilcox Solar Observatory (WSO) is also significantly reduced compared to prior cycles since the start of the program in 1976, the polar field in the northern hemisphere reversed in June 2012 and again in February 2014, that in the southern hemisphere reversed in July 2013. If updates of WSO data confirm the second reversal in northern solar hemisphere, it would pose a serious challenge to the Dynamo Theory. The long-term change in solar behavior may have begun in 1992, perhaps earlier. The physical underpinnings of these solar changes need to be understood and their effect on GCR modulation processes clarified. The study discusses the recent phenomena in the context of GCR modulation since 1900. These happenings affected our empirical predictions for the key parameters for the next two sunspot cycles (they may be progressively less active than sunspot cycle 24) but it enhanced support for our prediction that solar activity is descending into a Dalton-like grand minimum in the middle of the twentyfirst century, reducing the frequency of the coronal mass ejections; they determine the space weather affecting the quality of life on Earth, radiation dose for hardware and human activities in space as well as the frequency of large Forbush decreases at 1 a.u.

Ahluwalia, H. S.

2014-10-01

383

Comparisons of Integrated Radiation Transport Models with Microdosimetry Data in Spaceflight  

NASA Technical Reports Server (NTRS)

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.

Cucinotta, Francis A.; Nikjoo, H.; Kim, M. Y.; Hu, X.; Dicello, J. F.; Pisacane, V. L.

2006-01-01

384

The influence of cosmic rays on the size of the Antarctic Ozone Hole  

E-print Network

The Antarctic region in which severe ozone depletion has taken place is known as the ozone hole. This region has two basic indicators: the area, where the ozone abundance is low (size), and the quantity of ozone mass deficit (depth). The energetic particles that penetrate deeply into the atmosphere and galactic cosmic rays (GCR) modify the ozone abundance in the stratosphere. With this research project, we are looking for evidence of a connection between variations in the cosmic ray flux and variations in the size of the ozone hole. In addition, we are looking for signs of the kind of processes that physically connect GCR fluxes with variations in the stratospheric ozone hole size (OHS) in the Antarctic region. With this goal in mind, we also analyze here the atmospheric temperature (AT) anomalies, which have often been linked with such variations. Using Morlet's wavelet spectral analysis to compute the coherence between two time series, we found that during the analyzed period (1982-2005), there existed a common signal of around 3 and 5 years between the OHS and GCR time series, during September and November, respectively. In both cases, the relationship showed a time-dependent anti-correlation between the two series. On the other hand, for October the analysis showed a time-dependent correlation that occurs around 1.7 years. These results seem to indicate that there exist at least two kinds of modulation processes of GCR fluxes on the OHS that work simultaneously but that change their relative relevance along the timeline.

M. Alvarez Madrigal; J. Perez Peraza; V. M. Velasco

2010-01-15

385

Radiation Transport Properties of Potential In Situ-Developed Regolith-Epoxy Materials for Martian Habitats  

NASA Technical Reports Server (NTRS)

Mission crews in space outside the Earth s magnetic field will be exposed to high energy heavy charged particles in the galactic cosmic radiation (GCR). These highly ionizing particles will be a source of radiation risk to crews on extended missions to the Moon and Mars, and the biological effects of and countermeasures to the GCR have to be investigated as part of the planning of exploration-class missions. While it is impractical to shield spacecraft and planetary habitats against the entire GCR spectrum, biological and physical studies indicate that relatively modest amounts of shielding are effective at reducing the radiation dose. However, nuclear fragmentation in the shielding materials produces highly penetrating secondary particles, which complicates the problem: in some cases, some shielding is worse than none at all. Therefore the radiation transport properties of potential shielding materials need to be carefully investigated. One intriguing option for a Mars mission is the use of material from the Martian surface, in combination with chemicals carried from Earth and/or fabricated from elements found in the Martian atmosphere, to construct crew habitats. We have measured the transmission properties of epoxy-Martian regolith composites with respect to heavy charged particles characteristic of the GCR ions which bombard the Martian surface. The composites were prepared at NASA Langley Research Center using simulated Martian regolith, in the process also evaluating fabrication methods which could lead to technologies for in situ fabrication on Mars. Initial evaluation of the radiation shielding properties is made using radiation transport models developed at NASA-LaRC, and the results of these calculations are used to select the composites with the most favorable radiation transmission properties. These candidates are then evaluated at particle accelerators which produce beams of heavy charged particles representative in energy and charge of the radiation at the surface of Mars. The ultimate objective is to develop the models into a design tool for use by mission planners, flight surgeons and radiation health specialists.

Miller, Jack; Heilbronn, Lawrence H.; Zeitlin, Cary J.; Wilson, John W.; Singleterry, Robert C., Jr.; Thibeault, Sheila Ann

2003-01-01

386

An Algorithm for the Transport of Anisotropic Neutrons  

NASA Technical Reports Server (NTRS)

One major obstacle to human space exploration is the possible limitations imposed by the adverse effect of long-term exposure to the space environment. Even before human spaceflight began, the potentially brief exposure of astronauts to the very intense random solar particle events (SPE) were of great concern. A new challenge appears in deep space exploration from exposure to the low-intensity heavy-ion flux of the galactic cosmic rays (GCR) since the missions are of long duration and the accumulated GCR exposures can be high. Because cancer induction rates increase behind low to rather large thicknesses of aluminum shielding, according to available biological data on mammalian exposures to GCR like ions, the shield requirements for a Mars mission are prohibitively expensive in terms of mission launch costs. Therefore, a critical issue in the Human Exploration and Development of Space enterprise is cost effective mitigation of risk associated with ionizing radiation exposure. In order to estimate astronaut risk to GCR exposure and associated cancer risks and health hazards, it is necessary to do shield material studies. To determine an optimum radiation shield material it is necessary to understand nuclear interaction processes such as fragmentation and secondary particle production which is a function of energy dependent cross sections. This requires knowledge of material transmission characteristics either through laboratory testing or improved theoretical modeling. Here ion beam transport theory is of importance in that testing of materials in the laboratory environment generated by particle accelerators is a necessary step in materials development and evaluation for space use. The approximations used in solving the Boltzmann transport equation for the space setting are often not sufficient for laboratory work and those issues are a major emphasis of the present work.

Tweed, J.

2005-01-01

387

MCNP6 Cosmic-Source Option  

SciTech Connect

MCNP is a Monte Carlo radiation transport code that has been under development for over half a century. Over the last decade, the development team of a high-energy offshoot of MCNP, called MCNPX, has implemented several physics and algorithm improvements important for modeling galactic cosmic-ray (GCR) interactions with matter. In this presentation, we discuss the latest of these improvements, a new Cosmic-Source option, that has been implemented in MCNP6.

McKinney, Gregg W [Los Alamos National Laboratory; Armstrong, Hirotatsu [Los Alamos National Laboratory; James, Michael R [Los Alamos National Laboratory; Clem, John [University of Delaware, BRI; Goldhagen, Paul [DHS, National Urban Security Technology Laboratory

2012-06-19

388

Energetic Particles at Voyager 1 in the Interstellar Medium and Voyager 2 in the Heliosheath  

NASA Astrophysics Data System (ADS)

Voyager 1 (at 128 AU, N35(°) lat. in mid-2014) evidently made a transition from the heliosheath into the local interstellar medium on or about doy 238 of 2012 at 121.6 AU. Prior to the doy 238 transition, Voyager 1 passed through two partial “depletion regions” during 2012 doys 210-215 and 226-234. In the depletion regions, intensities of charged particles of heliospheric origin (suprathermal ions, ACRs, low-energy electrons) decreased, while those of galactic origin (GCR ions and electrons) increased, and the magnetic field intensity increased but its direction remained close to that measured in the heliosheath. Low-energy helosheath electrons 26-70 keV begin decreasing ?2012.5, dropped sharply at the 1st GCR increase, made a weak recovery between 1st and 2nd GCR increase, and dropped to background levels after 2nd GCR increase. After 2012/238 the intensity decreases of protons 3-30 MeV showed pancake-like pitch-angle distributions. At Voyager 2 (at 105 AU, S31(°) lat.), which is still in the heliosheath, low-energy ions from at least 0.03 to 30 MeV showed increasing 1st order anisotropies during the period 2013.0-2013.3 that are directed in the +T direction, i.e., away from the heliosheath nose toward its flank from the perspective of Voyager 2 (at a longitude ?45(°) from the nose). Both the intensities and associated partial pressures of low-energy heliosheath ions had decreased at Voyager 2 since its termination shock crossing on 2007/242. Intensities of suprathermal ions ?100 keV, which dropped by a factor ?7 from the shock crossing to 2013.3, have since increased by a factor ?2, apparently in response to a transient disturbance that is also associated with the enhanced tangential streaming of energetic ions in the +T direction.

Decker, Robert; Roelof, Edmond; Krimigis, Stamatios; Hill, Matthew

389

PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES: Ultra-Thin Silicon Carbon Nitride Film: a Promising Protective Coating for Read\\/Write Heads in Magnetic Storage Devices  

Microsoft Academic Search

Ultra-thin amorphous Si-C-N films, down to 2nm, have been synthesized by MW-ECR, plasma enhanced unbalanced magnetron sputtering. The friction coefficient of the film is only 0.11, determined in dry friction tests against the GCr15 ball at a load of 400 mN for 20 min. The films exhibit good protection against corrosion when they are immersed in a more severe corrosion

Peng Gao; Jun Xu; Wan-Yu Ding; Chuang Dong

2009-01-01

390

Photometric and Spectroscopic Monitoring of of Colliding-Wind X-ray Binaries in the Galactic Center  

Microsoft Academic Search

In the 2007A semester we performed spectroscopic follow-up of a large sample of Chandra X-ray sources having bright NIR counterparts. This resulted in the discovery of a 13 new colliding-wind Wolf-Rayet\\/O X- ray binaries in the GCR. These binaries are likely to have relatively small physical separations to account for the hard X-ray emission of their colliding winds. Such close

Jon Mauerhan; Mark Morris; Michael Muno

2008-01-01

391

Early Energetic Particle Irradiation of the HED Parent Body Regolith  

NASA Technical Reports Server (NTRS)

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

Bogard, D. D.; Garrison, D. H.; Rao, M. N.

1996-01-01

392

ANISOTROPY AS A PROBE OF THE GALACTIC COSMIC-RAY PROPAGATION AND HALO MAGNETIC FIELD  

SciTech Connect

The anisotropy of cosmic rays (CRs) in the solar vicinity is generally attributed to CR streaming due to the discrete distribution of CR sources or local magnetic field modulation. Recently, the two-dimensional large-scale CR anisotropy has been measured by many experiments in the TeV-PeV energy range in both hemispheres. The tail-in excess along the tangential direction of the local spiral arm and the loss cone deficit pointing to the north Galactic pole direction agree with what have been obtained in tens to hundreds of GeV. The persistence of the two large-scale anisotropy structures in such a wide energy range suggests that the anisotropy might be due to global streaming of the Galactic CRs (GCRs). This work tries to extend the observed CR anisotropy picture from the solar system to the whole galaxy. In such a case, we can find a new interesting signature, a loop of GCR streaming, of the GCR propagation. We further calculate the overall GCR streaming induced magnetic field, and find a qualitative consistency with the observed structure of the halo magnetic field.

Qu, Xiao-bo; Zhang, Yi; Liu, Cheng; Hu, Hong-bo [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Xue, Liang, E-mail: zhangyi@mail.ihep.ac.cn [School of Physics, Shandong University, Ji'nan 250100 (China)

2012-05-01

393

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

NASA Technical Reports Server (NTRS)

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.

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

2011-01-01

394

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

E-print Network

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...

Modzelewska, R

2015-01-01

395

Radiation exposure predictions for short-duration stay Mars missions.  

PubMed

The human radiation environment for several short-duration stay manned Mars missions is predicted using the Mission Radiation Calculation (MIRACAL) program, which was developed at NASA Langley Research Center. This program provides dose estimates for galactic cosmic rays (GCR) and large and ordinary solar proton flare events for various amounts of effective spacecraft shielding (both operational and storm shelter thicknesses) and a given time history of the spacecraft's heliocentric position. The results of this study show that most of the missions can survive the most recent large flares (if they were to occur at the missions' perihelion) if a 25 g/cm2 storm shelter is assumed. The dose predictions show that missions during solar minima (when solar flare activity is the lowest) are not necessarily the minimum dose cases, due to increased GCR contribution during this time period. The direct transfer mission studied has slightly lower doses than the outbound Venus swingby mission [on the order of 10-20 centi-Sieverts (cSv) lower], with the greatest dose differences for the assumed worst case scenario (when the large flares occur at perihelion). The GCR dose for a mission can be reduced by having the crew spend some fraction of its day nominally in the storm shelter (other than during flare events). PMID:11538210

Striepe, S A; Nealy, J E; Simonsen, L C

1992-01-01

396

Short-term and Long-term Variations of Dose Rate measured by MSL/RAD  

NASA Astrophysics Data System (ADS)

The Radiation Assessment Detector (RAD), onboard Mars Science Laboratory’s (MSL) rover Curiosity, measures the spectra of both energetic charged and neutral particles along with radiation dose rate at the surface of Mars. Several effects have been observed for the first time to influence the Galactic Cosmic Ray (GCR)-driven particle radiation on the surface: [a] short-term diurnal variations of the Martian atmospheric pressure caused by daily thermal tides [Rafkin 2014]; [b] long-term seasonal pressure changes in the Martian atmosphere; and [c] the modulation of the primary GCR fluxes by the heliospheric magnetic field, which correlates with long-term solar activities and heliospheric rotation. These concurrent factors affect the dose rate variations measured by RAD on the Martian surface. RAD also recorded the dose rate during the 253-day cruise phase of MSL from the Earth to Mars. The variations of the GCR-induced dose rates during quiet time period without the direct detection of Solar Particle Events (SPE) were solely driven by the changes of heliospheric conditions (i.e. [c]). The RAD cruise and surface dose measurements, along with the surface pressure data and the solar modulation factor, are analysed in order to understand how the long-term influences ([b] and [c]) individually correlate with the measured dose rates.

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

397

Spectrum and ionization rate of low-energy Galactic cosmic rays  

NASA Astrophysics Data System (ADS)

We consider the rate of ionization of diffuse and molecular clouds in the interstellar medium by Galactic cosmic rays (GCRs) in order to constrain its low-energy spectrum. We extrapolate the GCR spectrum obtained from PAMELA at high energies (?200 GeV nucleon-1) and a recently derived GCR proton flux at 1-200 GeV from observations of gamma-rays from molecular clouds, and find that the observed average Galactic ionization rate can be reconciled with this GCR spectrum if there is a low-energy cut-off for protons at 10-100 MeV. We also identify the flattening below a few GeV as being due to (a) decrease of the diffusion coefficient and dominance of convective loss at low energy and (b) the expected break in energy spectrum for a constant spectral index in momentum. We show that the inferred CR proton spectrum of ? for Ekin? few GeV is consistent with a power-law spectrum in momentum p-2.45± 0.4, which we identify as the spectrum at source. Diffusion loss at higher energies then introduces a steepening by E-? with ?˜ 1/3, making it consistent with high-energy measurements.

Nath, Biman B.; Gupta, Nayantara; Biermann, Peter L.

2012-09-01

398

MCNPX Cosmic Ray Shielding Calculations with the NORMAN Phantom Model  

NASA Technical Reports Server (NTRS)

The United States is planning manned lunar and interplanetary missions in the coming years. Shielding from cosmic rays is a critical aspect of manned spaceflight. These ventures will present exposure issues involving the interplanetary Galactic Cosmic Ray (GCR) environment. GCRs are comprised primarily of protons (approx.84.5%) and alpha-particles (approx.14.7%), while the remainder is comprised of massive, highly energetic nuclei. The National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) has commissioned a joint study with Los Alamos National Laboratory (LANL) to investigate the interaction of the GCR environment with humans using high-fidelity, state-of-the-art computer simulations. The simulations involve shielding and dose calculations in order to assess radiation effects in various organs. The simulations are being conducted using high-resolution voxel-phantom models and the MCNPX[1] Monte Carlo radiation-transport code. Recent advances in MCNPX physics packages now enable simulated transport over 2200 types of ions of widely varying energies in large, intricate geometries. We report here initial results obtained using a GCR spectrum and a NORMAN[3] phantom.

James, Michael R.; Durkee, Joe W.; McKinney, Gregg; Singleterry Robert

2008-01-01

399

Rigidity Dependence of the Long-Term Variations of Galactic Cosmic-Ray Intensity in Relation to the Interplanetary Magnetic-Field Turbulence: 1968 - 2002  

NASA Astrophysics Data System (ADS)

We studied the relationship between the power-law exponent ? on the rigidity R of the spectrum of galactic cosmic-ray (GCR) intensity variation ( ?D( R)/ D( R)? R - ? ) and the exponents ? y and ? z of the power spectral density (PSD) of the B y and B z components of the interplanetary magnetic field (IMF) turbulence (PSD˜ f - ? , where f is the frequency). We used the data from neutron monitors and IMF for the period of 1968 - 2002. The exponents ? y and ? z were calculated in the frequency interval ? f= f 2- f 1=3×10-6 Hz of the resonant frequencies ( f 1=1×10-6 Hz, f 2=4×10-6 Hz) that are responsible for the scattering of GCR particles with the rigidity range detected by neutron monitors. We found clear inverse correlations between ? and ? y or ? z when the time variations of the resonant frequencies were derived from in situ measurements of the solar wind velocity U sw and IMF strength B during 1968 - 2002. We argue that these inverse relations are a fundamental feature in the GCR modulation that is not restricted to the analyzed years of 1968 - 2002.

Siluszyk, M.; Iskra, K.; Alania, M. V.

2014-11-01

400

Calibration of the Galactic Cosmic Ray Flux  

NASA Technical Reports Server (NTRS)

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.

Mathew, K. J.; Marti, K.

2004-01-01

401

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

PubMed

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

Cucinotta, F A; Wilson, J W

1995-08-01

402

Galactic Cosmic Ray Intensity Response to Interplanetary Coronal Mass Ejections/Magnetic Clouds in 1995-2009  

NASA Technical Reports Server (NTRS)

We summarize the response of the galactic cosmic ray (CGR) intensity to the passage of the more than 300 interplanetary coronal mass ejections (ICMEs) and their associated shocks that passed the Earth during 1995-2009, a period that encompasses the whole of Solar Cycle 23. In approx.80% of cases, the GCR intensity decreased during the passage of these structures, i.e., a "Forbush decrease" occurred, while in approx.10% there was no significant change. In the remaining cases, the GCR intensity increased. Where there was an intensity decrease, minimum intensity was observed inside the ICME in approx.90% of these events. The observations confirm the role of both post-shock regions and ICMEs in the generation of these decreases, consistent with many previous studies, but contrary to the conclusion of Reames, Kahler, and Tylka (Astrophys. 1. Lett. 700, L199, 2009) who, from examining a subset of ICMEs with flux-rope-like magnetic fields (magnetic clouds) argued that these are "open structures" that allow free access of particles including GCRs to their interior. In fact, we find that magnetic clouds are more likely to participate in the deepest GCR decreases than ICMEs that are not magnetic clouds.

Richardson, I. G.; Cane, H. V.

2011-01-01

403

Space Radiation Cancer Risks and Uncertainities for Different Mission Time Periods  

NASA Technical Reports Server (NTRS)

Space radiation consists of solar particle events (SPEs), comprised largely of medium energy protons (less than several hundred MeV); and galactic cosmic ray (GCR), which includes high energy protons and high charge and energy (HZE) nuclei. For long duration missions, space radiation presents significant health risks including cancer mortality. Probabilistic risk assessment (PRA) is essential for radiation protection of crews on long term space missions outside of the protection of the Earth s magnetic field and for optimization of mission planning and costs. For the assessment of organ dosimetric quantities and cancer risks, the particle spectra at each critical body organs must be characterized. In implementing a PRA approach, a statistical model of SPE fluence was developed, because the individual SPE occurrences themselves are random in nature while the frequency distribution of SPEs depends strongly upon the phase within the solar activity cycle. Spectral variability of SPEs was also examined, because the detailed energy spectra of protons are important especially at high energy levels for assessing the cancer risk associated with energetic particles for large events. An overall cumulative probability of a GCR environment for a specified mission period was estimated for the temporal characterization of the GCR environment represented by the deceleration potential (theta). Finally, this probabilistic approach to space radiation cancer risk was coupled with a model of the radiobiological factors and uncertainties in projecting cancer risks. Probabilities of fatal cancer risk and 95% confidence intervals will be reported for various periods of space missions.

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

2012-01-01

404

[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

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

Mitrikas, V G

2014-01-01

405

Dexamethasone augments CXCR4-mediated signaling in resting human T cells via the activation of the Src kinase Lck  

PubMed Central

Dexamethasone (DM) is a synthetic member of the glucocorticoid (GC) class of hormones that possesses anti-inflammatory and immunosuppressant activity and is commonly used to treat chronic inflammatory disorders, severe allergies, and other disease states. Although GCs are known to mediate well-defined transcriptional effects via GC receptors (GCR), there is increasing evidence that GCs also initiate rapid nongenomic signaling events in a variety of cell types. Here, we report that DM induces the phosphorylation of Lck and the activation of other downstream mediators, including p59Fyn, Zap70, Rac1, and Vav in resting but not activated human T cells. DM treatment also augments CXCL12-mediated signaling in resting T cells through its cell surface receptor, CXCR4 resulting in the enhanced actin polymerization, Rac activation, and cell migration on ligand exposure. Lck was found to be a critical intermediate in these DM-induced signaling activities. Moreover, DM-mediated Lck phosphorylation in T cells was dependent on the presence of both the GCR and the CD45 molecule. Overall, these results elucidate additional nongenomic effects of DM and the GCR on resting human T cells, inducing Lck and downstream kinase activation and augmenting chemokine signaling and function. PMID:18840710

Ghosh, Manik C.; Baatar, Dolgor; Collins, Gary; Carter, Arnell; Indig, Fred; Biragyn, Arya

2009-01-01

406

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)

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

Koontz, Steven

2012-01-01

407

Radiation exposure predictions for short-duration stay Mars missions  

NASA Technical Reports Server (NTRS)

The human radiation environment for several short-duration stay manned Mars missions is predicted using the Mission Radiation Calculation program, which was developed at NASA Langley Research Center. This program provides dose estimates for Galactic cosmic rays (GCR) and large and ordinary solar proton flare events for various amounts of effective spacecraft shielding and a given time history of the spacecraft's heliocentric position. The results of this study show that most of the missions can survive the most recent large flares if a 25 g/sq cm storm shelter is assumed. The dose predictions show that missions during solar minima are not necessarily the minimum dose cases, due to increased GCR contribution during this time period. The direct transfer mission studied has slightly lower doses than the outbound Venus swingby mission, with the greatest dose differences for the assumed worst case scenario. The GCR dose for a mission can be reduced by having the crew spend some fraction of its day nominally in the storm shelter.

Striepe, Scott A.; Nealy, John E.; Simonsen, Lisa C.

1992-01-01

408

Probabilistic Assessment of Radiation Risk for Astronauts in Space Missions  

NASA Technical Reports Server (NTRS)

Accurate predictions of the health risks to astronauts from space radiation exposure are necessary for enabling future lunar and Mars missions. Space radiation consists of solar particle events (SPEs), comprised largely of medium energy protons, (less than 100 MeV); and galactic cosmic rays (GCR), which include protons and heavy ions of higher energies. While the expected frequency of SPEs is strongly influenced by the solar activity cycle, SPE occurrences themselves are random in nature. A solar modulation model has been developed for the temporal characterization of the GCR environment, which is represented by the deceleration potential, phi. The risk of radiation exposure from SPEs during extra-vehicular activities (EVAs) or in lightly shielded vehicles is a major concern for radiation protection, including determining the shielding and operational requirements for astronauts and hardware. To support the probabilistic risk assessment for EVAs, which would be up to 15% of crew time on lunar missions, we estimated the probability of SPE occurrence as a function of time within a solar cycle using a nonhomogeneous Poisson model to fit the historical database of measurements of protons with energy > 30 MeV, (phi)30. The resultant organ doses and dose equivalents, as well as effective whole body doses for acute and cancer risk estimations are analyzed for a conceptual habitat module and a lunar rover during defined space mission periods. This probabilistic approach to radiation risk assessment from SPE and GCR is in support of mission design and operational planning to manage radiation risks for space exploration.

Kim, Myung-Hee; DeAngelis, Giovanni; Cucinotta, Francis A.

2009-01-01

409

Stockholm School of Economics in Russia Working Paper #04-102 Russian Competitiveness in the Global Economy  

E-print Network

Draft: Please do not quote without the authors ’ permissionRussian Competitiveness in the Global Economy Using data from the World Economic Forum’s Global Competitiveness Report (GCR) and Michael Porter’s theories on economic development, this paper explores how competitive Russia is and what can be done to make Russia more competitive in forthcoming years. We show that Russia’s continued dependency on natural resources for economic growth is detrimental to the creation of competitive business within the country. This article uses time series data from the past three years from the GCR for Russia (which the authors collected) and compares it to GCR competitiveness data from other countries. In this article we identify the strengths and weaknesses of Russia’s current business environment, discuss current theories on economic development and consider case studies of three industry clusters where we consider Russia has potential to have a global competitive advantage: IT Outsourcing, Oil and Food Processing. We conclude by analyzing what needs to be done to assist Russia, and these industries in particular, in becoming Understanding how competitive Russia is today and how it can become more competitive

Thea Mills; Igor Dukeov; Carl F. Fey

2004-01-01

410

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

NASA Astrophysics Data System (ADS)

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.

Veretenenko, Svetlana; Ogurtsov, Maxim

411

The First Cosmic Ray Albedo Proton Map of the Moon  

NASA Astrophysics Data System (ADS)

The Lunar Reconnaissance Orbiter (LRO) has been observing the surface and environment of the Moon since June of 2009. The CRaTER instrument (Cosmic Ray Telescope for the Effects of Radiation) on LRO is designed to characterize the lunar radiation environment and its effects on simulated human tissue. CRaTER's multiple solid state detectors can be used to discriminate the different elements in the galactic cosmic ray (GCR) population above ~10 MeV/nucleon, and can also distinguish between primary GCR protons arriving from deep space and secondary albedo particles ejected from the lunar surface. We use protons coming up from the lunar surface with energies greater than 60 MeV to construct an albedo proton map of the Moon. The map accounts for variations in the secondary particles driven by fluctuations in the primary GCR population, and thus reveals any true spatial variations in the proton spallation yield related to elemental abundances in the regolith. Presently we find no significant differences in the yields from different regions on the Moon, although the anticipated collection of more data will improve the proton counting statistics. The average global proton yield has been increasing for the past several months, consistent with the reduction in lower-energy GCRs that is expected when solar activity increases.

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

2011-12-01

412

Nested Krylov methods and preserving the orthogonality  

NASA Technical Reports Server (NTRS)

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.

Desturler, Eric; Fokkema, Diederik R.

1993-01-01

413

Solar-Cosmic-Ray-Produced Nuclides in Extraterrestrial Matter  

NASA Technical Reports Server (NTRS)

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.

Reedy, Robert C.

2000-01-01

414

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

NASA Technical Reports Server (NTRS)

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.

Englert, Peter A. J.

1988-01-01

415

Solar-Cosmic-Ray-Produced Nuclides in Extraterrestrial Matter  

NASA Technical Reports Server (NTRS)

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.

Reedy, Robert C.

1999-01-01

416

LISA Pathfinder test-mass charging during galactic cosmic-ray flux short-term variations  

NASA Astrophysics Data System (ADS)

Metal free-floating test masses aboard the future interferometers devoted to gravitational wave detection in space are charged by galactic and solar cosmic rays with energies \\gt 100 MeV/n. This process represents one of the main sources of noise in the lowest frequency band (\\lt 10-3 Hz) of these experiments. We study here the charging of the LISA Pathfinder (LISA-PF) gold-platinum test masses due to galactic cosmic-ray (GCR) protons and helium nuclei with the Fluka Monte Carlo toolkit. Projections of the energy spectra of GCRs during the LISA-PF operations in 2015 are considered. This work was carried out on the basis of the solar activity level and solar polarity epoch expected for LISA-PF. The effects of GCR short-term variations are evaluated here for the first time. Classical Forbush decreases, GCR variations induced by the Sun rotation, and fluctuations in the LISA-PF frequency bandwidth are discussed.

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

2015-02-01

417

A computational model for an open-cycle gas core nuclear rocket  

SciTech Connect

A computational model of an open-cycle gas core nuclear rocket (GCR) is developed. The solution is divided into two distinct areas--thermal hydraulics and neutronics. To obtain the thermal-hydraulic solution, a computer code is written that solves the Navier-Stokes, energy, and species diffusion equations. The two-dimensional transport code TWODANT is used to obtain the neutronics solution. The thermal-hydraulic and neutronic models are coupled, and the solution proceeds in an iterative manner until a consistent power density profile is obtained. Various open-cycle GCR designs are evaluated. First, it is assumed that the fuel and propellant do not mix. In this ideal case, it is found that the limiting factor in determining thrust and specific impulse is the maximum allowable wall heat flux. Following this simplified study, the results from a complete thermal-hydraulic/neutronic solution are presented, and the use of alternate fuels and propellants is considered. Next, a parametric design study is conducted that examine the rocket performance of the open-cycle GCR as a function of various design and operational parameters. It is found that fuel containment is very adversely affected by high reactor power or rocket acceleration. Finally, some concepts are discussed that could help improve fuel containment.

Poston, D.I. [Los Alamos National Lab., NM (United States). Nuclear Systems Design and Analysis Group; Kammash, T. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Nuclear Engineering

1996-01-01

418

Radiation Shielding Optimization on Mars  

NASA Technical Reports Server (NTRS)

Future space missions to Mars will require radiation shielding to be optimized for deep space transit and an extended stay on the surface. In deep space, increased shielding levels and material optimization will reduce the exposure from most solar particle events (SPE) but are less effective at shielding against galactic cosmic rays (GCR). On the surface, the shielding provided by the Martian atmosphere greatly reduces the exposure from most SPE, and long-term GCR exposure is a primary concern. Previous work has shown that in deep space, additional shielding of common materials such as aluminum or polyethylene does not significantly reduce the GCR exposure. In this work, it is shown that on the Martian surface, almost any amount of aluminum shielding increases exposure levels for humans. The increased exposure levels are attributed to neutron production in the shield and Martian regolith as well as the electromagnetic cascade induced in the Martian atmosphere. This result is significant for optimization of vehicle and shield designs intended for the surface of Mars.

Slaba, Tony C.; Mertens, Chris J.; Blattnig, Steve R.

2013-01-01

419

Development of Liquid-Vapor Core Reactors with MHD Generator for Space Power and Propulsion Applications  

SciTech Connect

Any reactor that utilizes fuel consisting of a fissile material in a gaseous state may be referred to as a gaseous core reactor (GCR). Studies on GCRs have primarily been limited to the conceptual phase, mostly due to budget cuts and program cancellations in the early 1970's. A few scientific experiments have been conducted on candidate concepts, primarily of static pressure fissile gas filling a cylindrical or spherical cavity surrounded by a moderating shell, such as beryllium, heavy water, or graphite. The main interest in this area of nuclear power generation is for space applications. The interest in space applications has developed due to the promise of significant enhancement in fuel utilization, safety, plant efficiency, special high-performance features, load-following capabilities, power conversion optimization, and other key aspects of nuclear power generation. The design of a successful GCR adapted for use in space is complicated. The fissile material studied in the pa st has been in a fluorine compound, either a tetrafluoride or a hexafluoride. Both of these molecules have an impact on the structural material used in the making of a GCR. Uranium hexafluoride as a fuel allows for a lower operating temperature, but at temperatures greater than 900K becomes essentially impossible to contain. This difficulty with the use of UF6 has caused engineers and scientists to use uranium tetrafluoride, which is a more stable molecule but has the disadvantage of requiring significantly higher operating temperatures. Gas core reactors have traditionally been studied in a steady state configuration. In this manner a fissile gas and working fluid are introduced into the core, called a cavity, that is surrounded by a reflector constructed of materials such as Be or BeO. These reactors have often been described as cavity reactors because the density of the fissile gas is low and criticality is achieved only by means of the reflector to reduce neutron leakage from the core. Still there are problems of containment since many of the proposed vessel materials such as W or Mo have high neutron cross sections making the design of a critical system difficult. There is also the possibility for a GCR to remain in a subcritical state, and by the use of a shockwave mechanism, increase the pressure and temperature inside the core to achieve criticality. This type of GCR is referred to as a shockwave-driven pulsed gas core reactor. These two basic designs were evaluated as advance concepts for space power and propulsion.

Samim Anghaie

2002-08-13

420

The Hazards of Underspecified Models: The Case of Symmetry in Everyday Predictions  

ERIC Educational Resources Information Center

Should one be more confident when predicting the whole (or an event based on a larger sample) from the part (or an event based on a smaller sample) than when predicting the reverse? The relevant literature on judgment under uncertainty argues that such predictions are symmetrical but that, as an empirical matter, people often fail to appreciate…

Sedlmeier, Peter; Kilinc, Berna

2004-01-01

421

Solar Drivers of 11-yr and Long-Term Cosmic Ray Modulation  

NASA Technical Reports Server (NTRS)

In the current paradigm for the modulation of galactic cosmic rays (GCRs), diffusion is taken to be the dominant process during solar maxima while drift dominates at minima. Observations during the recent solar minimum challenge the pre-eminence of drift: at such times. In 2009, the approx.2 GV GCR intensity measured by the Newark neutron monitor increased by approx.5% relative to its maximum value two cycles earlier even though the average tilt angle in 2009 was slightly larger than that in 1986 (approx.20deg vs. approx.14deg), while solar wind B was significantly lower (approx.3.9 nT vs. approx.5.4 nT). A decomposition of the solar wind into high-speed streams, slow solar wind, and coronal mass ejections (CMEs; including postshock flows) reveals that the Sun transmits its message of changing magnetic field (diffusion coefficient) to the heliosphere primarily through CMEs at solar maximum and high-speed streams at solar minimum. Long-term reconstructions of solar wind B are in general agreement for the approx. 1900-present interval and can be used to reliably estimate GCR intensity over this period. For earlier epochs, however, a recent Be-10-based reconstruction covering the past approx. 10(exp 4) years shows nine abrupt and relatively short-lived drops of B to < or approx.= 0 nT, with the first of these corresponding to the Sporer minimum. Such dips are at variance with the recent suggestion that B has a minimum or floor value of approx.2.8 nT. A floor in solar wind B implies a ceiling in the GCR intensity (a permanent modulation of the local interstellar spectrum) at a given energy/rigidity. The 30-40% increase in the intensity of 2.5 GV electrons observed by Ulysses during the recent solar minimum raises an interesting paradox that will need to be resolved.

Cliver, E. W.; Richardson, I. G.; Ling, A. G.

2011-01-01

422

Probing Our Heliospheric History II  

NASA Astrophysics Data System (ADS)

A physical relationship between our local interstellar medium (ISM), galactic cosmic rays (GCR), and our planetary environment has long been a subject of interest to the astronomical community. Clouds of sufficient density to compress the heliosphere to within 1 AU are commonly seen throughout the galactic environment, including within the Local Bubble (LB). Such a compression would lead to an increase in the GCR flux at 1 AU and would have drastic consequences for many planetary processes such as atmospheric chemistry, lightning production, cloud cover, and DNA mutation rates for surface organisms. Prior to this work, we derived a column density profile of the ISM toward 49 bright stars along a narrow cone centered on the historical solar path. High resolution spectra were taken of NaI and CaII absorption out to a distance of 610 pc, with a median separation distance of 11 pc between adjacent stars. No absorption is seen out to a distance of 120 pc (consistent with the LB), but a complex number of absorbers is seen beyond. We now present the detection of several distinct clouds, their associated column densities, radial velocities, inferred distances, and size constraints. This combination of cloud properties allows us to derive a volume density profile of the ISM in the Sun's “rear-view mirror,” which represents one plausible record of actual ISM encounters for the Sun. We also make use of empirical relations to determine the effect these clouds would have on the historical heliosphere. Our analysis suggests that within the last 10 million years, if the Sun encountered a cloud with the same properties as we have detected along the solar historical trajectory, the Sun's termination shock would have resided inside the orbit of Uranus, with a GCR flux at Earth an order of magnitude greater than it is currently.

Wyman, Katherine; Redfield, S.

2012-05-01

423

Effect of the shrinking dipole on solar-terrestrial energy input to the Earth's atmosphere  

NASA Astrophysics Data System (ADS)

The global average temperature of the Earth is rising rapidly. This rise is primarily attributed to the release of greenhouse gases as a result of human activity. However, it has been argued that changes in radiation from the Sun might play a role. Most energy input to the Earth is light in the visible spectrum. Our best measurements suggest this power input has been constant for the last 40 years (the space age) apart from a small 11-year variation due to the solar cycle of sunspot activity. Another possible energy input from the Sun is the solar wind. The supersonic solar wind carries the magnetic field of the Sun into the solar system. As it passes the Earth it can connect to the Earth's magnetic field whenever it is antiparallel t the Earth's field. This connection allows mass, momentum, and energy from the solar wind to enter the magnetosphere producing geomagnetic activity. Ultimately much of this energy is deposited at high latitudes in the form of particle precipitation (aurora) and heating by electrical currents. Although the energy input by this process is miniscule compared to that from visible radiation it might alter the absorption of visible radiation. Two other processes affected by the solar cycle are atmospheric entry of galactic cosmic rays (GCR) and solar energetic protons (SEP). A weak solar magnetic field at sunspot minimum facilitates GCR entry which has been implicated in creation of clouds. Large coronal mass ejections and solar flares create SEP at solar maximum. All of these alternative energy inputs and their effects depend on the strength of the Earth's magnetic field. Currently the Earth's field is decreasing rapidly and conceivably might reverse polarity in 1000 years. In this paper we describe the changes in the Earth's magnetic field and how this might affect GCR, SEP, electrical heating, aurora, and radio propagation. Whether these effects are important in global climate change can only be determined by detailed physical models.

McPherron, R. L.

2011-12-01

424

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

NASA Astrophysics Data System (ADS)

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.

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

2013-10-01

425

EXPOSE-R cosmic radiation time profile  

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

426

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)

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.

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

2015-01-01

427

Probabilistic Assessment of Cancer Risk from Solar Particle Events  

NASA Technical Reports Server (NTRS)

For long duration missions outside of the protection of the Earth s magnetic field, space radiation presents significant health risks including cancer mortality. Space radiation consists of solar particle events (SPEs), comprised largely of medium energy protons (less than several hundred MeV); and galactic cosmic ray (GCR), which include high energy protons and heavy ions. While the frequency distribution of SPEs depends strongly upon the phase within the solar activity cycle, the individual SPE occurrences themselves are random in nature. We estimated the probability of SPE occurrence using a non-homogeneous Poisson model to fit the historical database of proton measurements. Distributions of particle fluences of SPEs for a specified mission period were simulated ranging from its 5 th to 95th percentile to assess the cancer risk distribution. Spectral variability of SPEs was also examined, because the detailed energy spectra of protons are important especially at high energy levels for assessing the cancer risk associated with energetic particles for large events. We estimated the overall cumulative probability of GCR environment for a specified mission period using a solar modulation model for the temporal characterization of the GCR environment represented by the deceleration potential (^). Probabilistic assessment of cancer fatal risk was calculated for various periods of lunar and Mars missions. This probabilistic approach to risk assessment from space radiation is in support of mission design and operational planning for future manned space exploration missions. In future work, this probabilistic approach to the space radiation will be combined with a probabilistic approach to the radiobiological factors that contribute to the uncertainties in projecting cancer risks.

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

2010-01-01

428

Estimation of Effective Doses for Radiation Cancer Risks on ISS, Lunar, and Mars Missions with Space Radiation Measurement  

NASA Technical Reports Server (NTRS)

Radiation protection practices define the effective dose as a weighted sum of equivalent dose over major sites for radiation cancer risks. Since a crew personnel dosimeter does not make direct measurement of effective dose, it has been estimated with skin-dose measurements and radiation transport codes for ISS and STS missions. The Phantom Torso Experiment (PTE) of NASA s Operational Radiation Protection Program has provided the actual flight measurements of active and passive dosimeters which were placed throughout the phantom on STS-91 mission for 10 days and on ISS Increment 2 mission. For the PTE, the variation in organ doses, which is resulted by the absorption and the changes in radiation quality with tissue shielding, was considered by measuring doses at many tissue sites and at several critical body organs including brain, colon, heart, stomach, thyroid, and skins. These measurements have been compared with the organ dose calculations obtained from the transport models. Active TEPC measurements of lineal energy spectra at the surface of the PTE also provided the direct comparison of galactic cosmic ray (GCR) or trapped proton dose and dose equivalent. It is shown that orienting the phantom body as actual in ISS is needed for the direct comparison of the transport models to the ISS data. One of the most important observations for organ dose equivalent of effective dose estimates on ISS is the fractional contribution from trapped protons and GCR. We show that for most organs over 80% is from GCR. The improved estimation of effective doses for radiation cancer risks will be made with the resultant tissue weighting factors and the modified codes.

Kim, M.Y.; Cucinotta, F.A.

2005-01-01

429

Space Weather Nowcasting of Atmospheric Ionizing Radiation for Aviation Safety  

NASA Technical Reports Server (NTRS)

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.

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

430

Effect of cosmic rays on the latent atmosphere energy  

NASA Astrophysics Data System (ADS)

The value and the type of "response" in the ground pressure (over Apatity, Moscow and Yakutsk) depending on the effect of galactic cosmic rays (GCR) in the period of Forbush-decreases are analyzed. A few days are required for the noticeable effect from the release of latent energy on vast squares of the planet. So, to study the cosmic ray effect on the ground pressure at the latitudes considerably distant from the auroral zone but at which the Forbush - effects are noticeably manifested, Moscow and Yakutsk stations have been chosen. They are sufficiently distant in longitude but they are within middle latitudes. The effect of action of GCR on the atmosphere covers, at least, polar and mid-latitude regions of the Earth. Thus, the Forbush-decreases cause the increase of pressure by1-6 mb. In this case, the value of effect over different regions can differ by a factor of 2 -3. In Moscow it is6 mb, in Yakutsk1.5 mb, in Apatity 3 mb. At such a wide difference in amplitude the type of temporal changes doesn't have substantial differences. In all 3 points the maximum of effect falls on 13-14 days from the onset of the main Forbush -e f f ect phase. Its average duration in all points is approximately 10 -15 days. The ionization of air by GCR can essentially influence processes where the generation of water aerosols occurs. In the atmosphere there are always physical chemical conditions tender which, in the case of realization of aggregate transfers of water, the changes of ground pressure by (1-6) mb. Will occur. Thereby, such changes can be stronger by a factor of 2-3 in the damper and warmer atmosphere.

Timofeev, V.; Grigoryev, V.; Skryabin, N.; Samsonov, S.

431

Are Cosmic Rays Modulated beyond the Heliopause?  

NASA Astrophysics Data System (ADS)

We discuss the possible spatial variation of Galactic and anomalous cosmic rays (GCRs and ACRs) at and beyond the heliopause (HP). Remaining within the framework of the Parker transport equation and assuming incompressible plasma in the heliosheath, we consider highly idealized simple-flow models and compare our GCR results with recent publications of Scherer et al. and Strauss et al. First, we discuss an order-of-magnitude estimate and a simple spherical model to demonstrate that the modulation of GCRs beyond the HP must be quite small if the diffusion coefficient beyond the HP is greater than ?1026 cm2 s-1, a value that is two orders of magnitude smaller than the value of 1028 cm2 s-1 determined from observations of GCR composition. Second, we construct a non-spherical model, which allows lateral deflection of the flow and uses different diffusion coefficients parallel and perpendicular to the magnetic field. We find that modulation of GCRs beyond the HP remains small even if the perpendicular diffusion coefficient beyond the HP is quite small (?1022 cm2 s-1) as long as the parallel diffusion is sufficiently fast. We also consider the case when the parallel diffusion beyond the HP is fast, but the perpendicular diffusion is as small as ?1020 cm2 s-1 this results in a sharp, almost step-like increase of GCR flux (and decrease of ACRs) at the HP. Possible implications are briefly discussed. We further suggest the possibility that the observed sharp gradient of GCRs at the HP might push the HP closer to the Sun than previously thought.

Kóta, J.; Jokipii, J. R.

2014-02-01

432

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

E-print Network

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 mechanis