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Sample records for international geomagnetic reference

  1. The International Geomagnetic Reference Field, 2005

    USGS Publications Warehouse

    Rukstales, Kenneth S.; Love, Jeffrey J.

    2007-01-01

    This is a set of five world charts showing the declination, inclination, horizontal intensity, vertical component, and total intensity of the Earth's magnetic field at mean sea level at the beginning of 2005. The charts are based on the International Geomagnetic Reference Field (IGRF) main model for 2005 and secular change model for 2005-2010. The IGRF is referenced to the World Geodetic System 1984 ellipsoid. Additional information about the USGS geomagnetism program is available at: http://geomag.usgs.gov/

  2. International Geomagnetic Reference Field: the third generation.

    USGS Publications Warehouse

    Peddie, N.W.

    1982-01-01

    In August 1981 the International Association of Geomagnetism and Aeronomy revised the International Geomagnetic Reference Field (IGRF). It is the second revision since the inception of the IGRF in 1968. The revision extends the earlier series of IGRF models from 1980 to 1985, introduces a new series of definitive models for 1965-1976, and defines a provisional reference field for 1975- 1980. The revision consists of: 1) a model of the main geomagnetic field at 1980.0, not continuous with the earlier series of IGRF models together with a forecast model of the secular variation of the main field during 1980-1985; 2) definitive models of the main field at 1965.0, 1970.0, and 1975.0, with linear interpolation of the model coefficients specified for intervening dates; and 3) a provisional reference field for 1975-1980, defined as the linear interpolation of the 1975 and 1980 main-field models.-from Author

  3. International Geomagnetic Reference Field: the 12th generation

    NASA Astrophysics Data System (ADS)

    Thébault, Erwan; Finlay, Christopher C.; Beggan, Ciarán D.; Alken, Patrick; Aubert, Julien; Barrois, Olivier; Bertrand, Francois; Bondar, Tatiana; Boness, Axel; Brocco, Laura; Canet, Elisabeth; Chambodut, Aude; Chulliat, Arnaud; Coïsson, Pierdavide; Civet, François; Du, Aimin; Fournier, Alexandre; Fratter, Isabelle; Gillet, Nicolas; Hamilton, Brian; Hamoudi, Mohamed; Hulot, Gauthier; Jager, Thomas; Korte, Monika; Kuang, Weijia; Lalanne, Xavier; Langlais, Benoit; Léger, Jean-Michel; Lesur, Vincent; Lowes, Frank J.; Macmillan, Susan; Mandea, Mioara; Manoj, Chandrasekharan; Maus, Stefan; Olsen, Nils; Petrov, Valeriy; Ridley, Victoria; Rother, Martin; Sabaka, Terence J.; Saturnino, Diana; Schachtschneider, Reyko; Sirol, Olivier; Tangborn, Andrew; Thomson, Alan; Tøffner-Clausen, Lars; Vigneron, Pierre; Wardinski, Ingo; Zvereva, Tatiana

    2015-05-01

    The 12th generation of the International Geomagnetic Reference Field (IGRF) was adopted in December 2014 by the Working Group V-MOD appointed by the International Association of Geomagnetism and Aeronomy (IAGA). It updates the previous IGRF generation with a definitive main field model for epoch 2010.0, a main field model for epoch 2015.0, and a linear annual predictive secular variation model for 2015.0-2020.0. Here, we present the equations defining the IGRF model, provide the spherical harmonic coefficients, and provide maps of the magnetic declination, inclination, and total intensity for epoch 2015.0 and their predicted rates of change for 2015.0-2020.0. We also update the magnetic pole positions and discuss briefly the latest changes and possible future trends of the Earth's magnetic field.

  4. Simulation of the Geomagnetic Cut-off with GEANT using the International Geomagnetic Reference Field

    NASA Astrophysics Data System (ADS)

    Wentz, J.; Bercuci, A.; Vulpescu, B.

    2001-08-01

    The International Geomagnetic Reference Field is used in a GEANT3 simulation to calculate the geomagnetic cut-off for cosmic rays entering in the Earth's magnetic field. The calculations are done in the back tracking method, where antiprotons start from the top of atmosphere and are tracked to outer space. The geomagnetic cut-off functions are estimated in momentum steps of 0.2 GeV for 131 directions in 1655 locations covering in a nearly equidistant grid the surface of the Earth. For special locations, where neutrino or low energy muon data have been measured, the cut-off functions are calculated in a fine grid of 21601 directions. The estimated geomagnetic cut-offs can be verified by the experimental results for primary protons and helium nuclei measured in different geomagnetic latitudes during the shuttle mission of the AMS prototype. These precise tables of the geomagnetic cut-off can be used in the frame of the CORSIKA code to calculate atmospheric muon and neutrino fluxes.

  5. A proposed International Geomagnetic Reference Field for 1965- 1985.

    USGS Publications Warehouse

    Peddie, N.W.; Fabiano, E.B.

    1982-01-01

    A set of spherical harmonic models describing the Earth's main magnetic field from 1965 to 1985 has been developed and is proposed as the next revision of the International Geomagnetic Reference Field (IGRF). A tenth degree and order spherical harmonic model of the main field was derived from Magsat data. A series of eighth degree and order spherical harmonic models of the secular variation of the main field was derived from magnetic observatory annual mean values. Models of the main field at 1965, 1970, 1975, and 1980 were obtained by extrapolating the main-field model using the secular variation models.-Authors spherical harmonic models Earth main magnetic field Magsat data

  6. Analysis of geomagnetic secular variation during 1980-1985 and 1985- 1990, and geomagnetic models proposed for the 1991 revision of the International Geomagnetic Reference Field

    USGS Publications Warehouse

    Peddie, N.W.

    1992-01-01

    The secular variation of the main geomagnetic field during the periods 1980-1985 and 1985-1990 was analyzed in terms of spherical harmonics up to the eighth degree and order. Data from worldwide magnetic observatories and the Navy's Project MAGNET aerial surveys were used. The resulting pair of secular-variation models was used to update the Definitive Geomagnetic Reference Field (DGRF) model for 1980, resulting in new mainfield models for 1985.0 and 1990.0. These, along with the secular-variation model for 1985-1990, were proposed for the 1991 revision of the International Geomagnetic Reference Field (IGRF). -Author

  7. NOAA/NGDC candidate models for the 12th generation International Geomagnetic Reference Field

    NASA Astrophysics Data System (ADS)

    Alken, Patrick; Maus, Stefan; Chulliat, Arnaud; Manoj, Chandrasekharan

    2015-05-01

    The International Geomagnetic Reference Field (IGRF) is a model of the geomagnetic main field and its secular variation, produced every 5 years from candidate models proposed by a number of international research institutions. For this 12th generation IGRF, three candidate models were solicited: a main field model for the 2010.0 epoch, a main field model for the 2015.0 epoch, and the predicted secular variation for the five-year period 2015 to 2020. The National Geophysical Data Center (NGDC), part of the National Oceanic and Atmospheric Administration (NOAA), has produced three candidate models for consideration in IGRF-12. The 2010 main field candidate was produced from Challenging Minisatellite Payload (CHAMP) satellite data, while the 2015 main field and secular variation candidates were produced from Swarm and Ørsted satellite data. Careful data selection was performed to minimize the influence of magnetospheric and ionospheric fields. The secular variation predictions of our parent models, from which the candidate models were derived, have been validated against independent ground observatory data.

  8. Evaluation of models proposed for the 1991 revision of the International Geomagnetic Reference Field

    USGS Publications Warehouse

    Peddie, N.W.

    1992-01-01

    The 1991 revision of the International Geomagnetic Reference Field (IGRF) comprises a definitive main-field model for 1985.0, a main-field model for 1990.0, and a forecast secular-variation model for the period 1990-1995. The five 1985.0 main-field models and five 1990.0 main-field models that were proposed have been evaluated by comparing them with one another, with magnetic observatory data, and with Project MAGNET aerial survey data. The comparisons indicate that the main-field models proposed by IZMIRAN, and the secular-variation model proposed jointly by the British Geological Survey and the US Naval Oceanographic Office, should be assigned relatively lower weight in the derivation of the new IGRF models. -Author

  9. International geomagnetic reference field 1980: a report by IAGA Division I working group.

    USGS Publications Warehouse

    Peddie, N.W.

    1982-01-01

    Describes the recommendations of the working group, which suggested additions to IGRF because of the cumulative effect of the inevitable uncertainties in the secular variation models which had led to unacceptable inaccuracies in the IGRF by the late 1970's. The recommendations were accepted by the International Association of Geomagnetism and Aeronomy on August 15, 1981 at the 4th Scientific Assembly, Edinburgh. An extended table sets out spherical harmonic coefficients of the IGRF 1980.-R.House

  10. Comparison of In-Situ Geomagnetic Field Measurement with International Geomagnetic Reference Field (IGRF) Model to Study the Ionosphere over Akure

    NASA Astrophysics Data System (ADS)

    Oladeji Oloketuyi, Jacob

    2015-08-01

    The ionosphere over Akure, south-western Nigeria (7o 15'N 5o 12'E) was investigated for a period of two years (2005-2006) from direct observation and model. Ionosphere over Akure was monitored and measured using a locally produced magnetometer. The International Geomagnetic Reference Field (IGRF) model was used to evaluate the magnetic field over Akure at the same epoch as the direct measurements. The measured values were compared with model values at every local for discrepancies. Diurnal and Seasonal effects were investigated using the two means. The magnetic data generated from locally made magnetometer provided a comprehensive understanding of the geomagnetic variation over the region. The comparison of measured and modeled values showed remarkable deviation. The discrepancies in the values may be attributed to local sources captured in the direct measurements.

  11. Assessment of models proposed for the 1985 revision of the international geomagnetic reference field

    USGS Publications Warehouse

    Peddie, N.W.; Zunde, A.K.

    1987-01-01

    Geomagnetic measurements from land, marine and aerial surveys conducted in the years 1945-1964 were used to test the 14 models proposed as additions, for that period, to the series of definitive geomagnetic reference field (DGRF) models. Overall, NASA's 'SFAS' models and the BGS (British Geological Survey) models agree best with these data. Comparisons of the two proposed definitive main-field models for 1980.0, with each other and with the existing IGRF 1980 main-field model, show mostly close agreement, with the greatest absolute differences (several tens of nanotesla) occurring in the region of Antarctica. Comparison of the the three proposed forecast secular-variation models for 1985-1990 with estimates of recent rates of change at 148 magnetic observatories shows that the IZMIRAN (U.S.S.R.) and USGS models are in closest agreement with these data. ?? 1987.

  12. An assessment of the near-surface accuracy of the international geomagnetic reference field 1980 model of the main geomagnetic field

    USGS Publications Warehouse

    Peddie, N.W.; Zunde, A.K.

    1985-01-01

    The new International Geomagnetic Reference Field (IGRF) model of the main geomagnetic field for 1980 is based heavily on measurements from the MAGSAT satellite survey. Assessment of the accuracy of the new model, as a description of the main field near the Earth's surface, is important because the accuracy of models derived from satellite data can be adversely affected by the magnetic field of electric currents in the ionosphere and the auroral zones. Until now, statements about its accuracy have been based on the 6 published assessments of the 2 proposed models from which it was derived. However, those assessments were either regional in scope or were based mainly on preliminary or extrapolated data. Here we assess the near-surface accuracy of the new model by comparing it with values for 1980 derived from annual means from 69 magnetic observatories, and by comparing it with WC80, a model derived from near-surface data. The comparison with observatory-derived data shows that the new model describes the field at the 69 observatories about as accurately as would a model derived solely from near-surface data. The comparison with WC80 shows that the 2 models agree closely in their description of D and I near the surface. These comparisons support the proposition that the new IGRF 1980 main-field model is a generally accurate description of the main field near the Earth's surface in 1980. ?? 1985.

  13. A 2015 International Geomagnetic Reference Field (IGRF) candidate model based on Swarm's experimental absolute magnetometer vector mode data

    NASA Astrophysics Data System (ADS)

    Vigneron, Pierre; Hulot, Gauthier; Olsen, Nils; Léger, Jean-Michel; Jager, Thomas; Brocco, Laura; Sirol, Olivier; Coïsson, Pierdavide; Lalanne, Xavier; Chulliat, Arnaud; Bertrand, François; Boness, Axel; Fratter, Isabelle

    2015-06-01

    Each of the three satellites of the European Space Agency Swarm mission carries an absolute scalar magnetometer (ASM) that provides the nominal 1-Hz scalar data of the mission for both science and calibration purposes. These ASM instruments, however, also deliver autonomous 1-Hz experimental vector data. Here, we report on how ASM-only scalar and vector data from the Alpha and Bravo satellites between November 29, 2013 (a week after launch) and September 25, 2014 (for on-time delivery of the model on October 1, 2014) could be used to build a very valuable candidate model for the 2015.0 International Geomagnetic Reference Field (IGRF). A parent model was first computed, describing the geomagnetic field of internal origin up to degree and order 40 in a spherical harmonic representation and including a constant secular variation up to degree and order 8. This model was next simply forwarded to epoch 2015.0 and truncated at degree and order 13. The resulting ASM-only 2015.0 IGRF candidate model is compared to analogous models derived from the mission's nominal data and to the now-published final 2015.0 IGRF model. Differences among models mainly highlight uncertainties enhanced by the limited geographical distribution of the selected data set (essentially due to a lack of availability of data at high northern latitude satisfying nighttime conditions at the end of the time period considered). These appear to be comparable to differences classically observed among IGRF candidate models. These positive results led the ASM-only 2015.0 IGRF candidate model to contribute to the construction of the final 2015.0 IGRF model.

  14. Development of a Geomagnetic Storm Correction to the International Reference Ionosphere E-Region Electron Densities Using TIMED/SABER Observations

    NASA Technical Reports Server (NTRS)

    Mertens, C. J.; Xu, X.; Fernandez, J. R.; Bilitza, D.; Russell, J. M., III; Mlynczak, M. G.

    2009-01-01

    Auroral infrared emission observed from the TIMED/SABER broadband 4.3 micron channel is used to develop an empirical geomagnetic storm correction to the International Reference Ionosphere (IRI) E-region electron densities. The observation-based proxy used to develop the storm model is SABER-derived NO+(v) 4.3 micron volume emission rates (VER). A correction factor is defined as the ratio of storm-time NO+(v) 4.3 micron VER to a quiet-time climatological averaged NO+(v) 4.3 micron VER, which is linearly fit to available geomagnetic activity indices. The initial version of the E-region storm model, called STORM-E, is most applicable within the auroral oval region. The STORM-E predictions of E-region electron densities are compared to incoherent scatter radar electron density measurements during the Halloween 2003 storm events. Future STORM-E updates will extend the model outside the auroral oval.

  15. Geomagnetic Disturbances Caused by Internal Atmospheric Dynamics

    NASA Technical Reports Server (NTRS)

    Sonneman, G.

    1984-01-01

    It is commonly believed that geomagnetic disturbances are caused by external influences connected with the solar wind. The 27-day recurrence of perturbations seems to be a strong hint for this interaction. But frequently geomagnetic disturbances occur without any relation to sunspot numbers or radiowave fluxes. This was one of the reasons for introducing hypothetical M-regions on the Sun and their relation to solar wind activities. Only one half of the variance of the geomagnetic AL-index could be related to the solar wind. Therefore it is concluded that internal processes of the magnetosphere were responsible for additional geomagnetic activity. Arguments, which might lead to the suggestion of geomagnetic disturbances as being caused by internal atmospheric dynamics are discussed and a rather preliminary scenario of those processes is proposed.

  16. International reference ionosphere 1990

    NASA Technical Reports Server (NTRS)

    Bilitza, Dieter; Rawer, K.; Bossy, L.; Kutiev, I.; Oyama, K.-I.; Leitinger, R.; Kazimirovsky, E.

    1990-01-01

    The International Reference Ionosphere 1990 (IRI-90) is described. IRI described monthly averages of the electron density, electron temperature, ion temperature, and ion composition in the altitude range from 50 to 1000 km for magnetically quiet conditions in the non-auroral ionosphere. The most important improvements and new developments are summarized.

  17. Steady induction effects in geomagnetism. Part 1C: Geomagnetic estimation of steady surficial core motions: Application to the definitive geomagnetic reference field models

    NASA Technical Reports Server (NTRS)

    Voorhies, Coerte V.

    1993-01-01

    In the source-free mantle/frozen-flux core magnetic earth model, the non-linear inverse steady motional induction problem was solved using the method presented in Part 1B. How that method was applied to estimate steady, broad-scale fluid velocity fields near the top of Earth's core that induce the secular change indicated by the Definitive Geomagnetic Reference Field (DGRF) models from 1945 to 1980 are described. Special attention is given to the derivation of weight matrices for the DGRF models because the weights determine the apparent significance of the residual secular change. The derived weight matrices also enable estimation of the secular change signal-to-noise ratio characterizing the DGRF models. Two types of weights were derived in 1987-88: radial field weights for fitting the evolution of the broad-scale portion of the radial geomagnetic field component at Earth's surface implied by the DGRF's, and general weights for fitting the evolution of the broad-scale portion of the scalar potential specified by these models. The difference is non-trivial because not all the geomagnetic data represented by the DGRF's constrain the radial field component. For radial field weights (or general weights), a quantitatively acceptable explication of broad-scale secular change relative to the 1980 Magsat epoch must account for 99.94271 percent (or 99.98784 percent) of the total weighted variance accumulated therein. Tolerable normalized root-mean-square weighted residuals of 2.394 percent (or 1.103 percent) are less than the 7 percent errors expected in the source-free mantle/frozen-flux core approximation.

  18. Statistical signatures of geomagnetic storms with reference to delay distribution

    NASA Astrophysics Data System (ADS)

    Aslam, A. M.; Gwal, Ashok Kumar

    2016-07-01

    This paper presents a statistical study on the nature and association of time delay (between IMF Bz and Dst) with various solar wind parameters and Inter planetary Magnetic field components. The study integrally covers all (634 storms) the geomagnetic storms observed during 1996 to 2011. We have calculated the time delay (∆T) between the peak values of IMF Bz and minimum Dst for each event and statistically investigated its relation with various solar wind parameters and IMF. For this analysis we have taken Solar wind parameters; Velocity, Density, Plasma beta and Temperature as well as IMF Bz, into consideration. We have categorized the storms into three categories based on the Dst Index as weak (-30nT ≤ Dst ≤ -50nT), moderate (-50nT ≤ Dst ≤ -100nT) and intense (Dst ≤ -100nT) storms. The relation of delay with solar wind parameters and IMF components were studied separately for different classes of storms and for different delays viz. 0,1,2,3,4 (hours). From our analysis we are able to draw some interesting inferences. The fact, that the characteristic feature describing the geoeffectiveness of the IMF is its z-component; Bz, and the electric field component -V× Bz, stands true for all delay classes of the storms. The time delay (∆T) between peak values of IMF Bz and minimum Dst can vary in a wide range and mostly varies from 0-10 hours. However, it was found that a major percentage (~80 %) of the storms have a 0 - 4 hour delay. Meanwhile Temperature, density and plasma beta seems to have no significant association with the storm intensity.

  19. The Development of a Dynamic Geomagnetic Cutoff Rigidity Model for the International Space Station

    NASA Technical Reports Server (NTRS)

    Smart, D. F.; Shea, M. A.

    1999-01-01

    We have developed a computer model of geomagnetic vertical cutoffs applicable to the orbit of the International Space Station. This model accounts for the change in geomagnetic cutoff rigidity as a function of geomagnetic activity level. This model was delivered to NASA Johnson Space Center in July 1999 and tested on the Space Radiation Analysis Group DEC-Alpha computer system to ensure that it will properly interface with other software currently used at NASA JSC. The software was designed for ease of being upgraded as other improved models of geomagnetic cutoff as a function of magnetic activity are developed.

  20. The International Celestial Reference System

    NASA Astrophysics Data System (ADS)

    Fomalont, E.

    2016-05-01

    The International Celestial Reference System (ICRS) is a set of prescriptions, conventions, observational techniques and modeling required to define an celestial inertial frame. The origin of the frame is the solar-system barycenter. The ICRS was adopted by the International Astronomical Union in 1997 as the replacement of the FK5 system. The frame is called the International Celestial Reference Frame (ICRF), and is realized (defined) by the accurate position of 295 radio sources, distributed over the sky, and the accuracy of the frame orientation is about 10 microarcsec. This review will cover: the history of the development of the ICRS; the basics of the major observational technique of Very Long Baseline Interferometry; the use of the fundamental observable, the group delay; experimental strategies to optimize the accuracy; the computational methods for analyzing the large data base; the two major error limitations; and the possible of ICRS/Gaia interactions.

  1. Mysterious misalignments between geomagnetic and stellar reference frames seen in CHAMP and Swarm satellite measurements

    NASA Astrophysics Data System (ADS)

    Maus, Stefan

    2015-12-01

    The orientation of a spacecraft in Low Earth Orbit can be determined accurately from either magnetic field measurements or star camera images. Ideally, the independently computed spacecraft attitudes should agree. However, we find that the German CHAMP and European Space Agency triple-satellite Swarm geomagnetic satellites exhibit consistent misalignments between the stellar and geomagnetic reference frames, which oscillate with the local time of the orbit. Having an amplitude of 20 arcsec, these oscillations are more than an order of magnitude larger than the stability of the optical bench, which cohosts the magnetometers and star cameras. The misalignments could originate either from the magnetometer or star camera measurements. On one hand, as-yet-unknown external magnetic field contributions could appear as a rotation of the geomagnetic reference frame. On the other hand, the observed misalignments agree in amplitude and phase with the effects of stellar aberration, caused by the movement of the star cameras relative to the light rays emitted by the stars. This is surprising because stellar aberration is allegedly already corrected for by the star image processing system. Resolving these mysterious misalignments is key to fulfilling the measurement accuracy requirements and science objectives of the ongoing Swarm mission. If caused by stellar aberration, fully correcting for this effect could significantly improve the attitude accuracy not only of CHAMP and Swarm, but also of several other past and ongoing scientific satellite missions.

  2. The International Reference Ionosphere - 45 Years of International Space Weather Collaboration

    NASA Astrophysics Data System (ADS)

    Bilitza, D.; Reinisch, B. W.; Rawer, K. M.

    2015-12-01

    The International Reference Ionosphere (IRI) project was started in 1970 when the Committee on Space Research (COSPAR) and the International Union of Radio Science (URSI) joined forces to establish an internationally accepted reference model for the ionosphere. COSPAR needed such a specification for the evaluation of environmental effects on spacecraft and experiments in space, and URSI for radiowave propagation studies and applications. Because of this operational needs both unions requested that IRI be based primarily on data using all available and reliable data sources from space and ground. Similar activities had been started for the Atmosphere with the COSPAR International Reference Atmosphere (CIRA) model and for the Earth's magnetic field with the International Geomagnetic Reference Field (IGRF) model of the International Association of Geomagnetism and Aeronomy (IAGA). This presentation will give a brief overview over the IRI project and the progress made since its inception. An important milestone was reached early last year when IRI was voted to become the ISO standard for the ionosphere; the International Standardization Organization (ISO) is in charge of establishing and publishing international standards. This talk will discuss the most recent status of IRI activities including the development of a Real-Time IRI and the IRI 2015 Workshop, the first COSPAR Capacity Building Workshop on a Space Weather topic, that will be held in Bangkok from November 2 to 13. The IRI model is heavily used for a wide range of applications in science, engineering and education. We will discuss some of the more important ones of these applications and present measures of success that underline the superior performance of the model and the wide acceptance in the science community and science-interested public.

  3. Geomagnetic survey and geomagnetic model research in China

    NASA Astrophysics Data System (ADS)

    Gu, Zuowen; Zhan, Zhijia; Gao, Jintian; Han, Wei; An, Zhenchang; Yao, Tongqi; Chen, Bin

    2006-06-01

    The geomagnetic survey at 135 stations in China were carried out in 2003. These stations are with better environmental condition and small magnetic field gradient (<5 nT/m). In the field survey, the geomagnetic declination D, the inclination I and the total intensity F were measured. Ashtech ProMark2 differential GPS (Global Positioning System) was used in measuring the azimuth, the longitude, the latitude and the elevation at these stations. The accuracy of the azimuth is 0.1'. The geomagnetic survey data were reduced using the data at geomagnetic observatories in China. The mean standard deviations of the geomagnetic reduced values are: <1.5 nT for F, <0.5' for D and I. Using the geomagnetic data which include the data at 135 stations and 35 observatories in China, and the data at 38 IGRF (International Geomagnetic Reference Field) calculation points in China's adjacent regions, the Taylor polynomial model and the spherical cap harmonic model were calculated for the geomagnetic field in China. The truncation order of the Taylor polynomial model is 5, and its original point is at 36.0°N and 104.5°E. Based on the geomagnetic anomalous values and using the method of spherical cap harmonic (SCH) analysis, the SCH model of the geomagnetic anomalous field was derived. In the SCH model, the pole of the spherical cap is at 36.0°N and 104.5°E, and the half-angle is 30°, the truncation order K= 8 is determined according to the mean square deviation between the model calculation value and the observation value, the AIC (Akaike Information Criterion) and the distribution of geomagnetic field.

  4. The International Reference Preparation of Gramicidin*

    PubMed Central

    Lightbown, J. W.; Bond, Jillian M.; Woodward, Patricia M.

    1967-01-01

    The National Institute for Medical Research, London, was requested by the WHO Expert Committee on Biological Standardization to establish an International Reference Preparation of Gramicidin. This preparation was needed to standardize preparations of gramicidin containing predominantly gramicidin A, B and C, for which purpose the International Reference Preparation of Gramicidin S cannot be used. A batch of 100 g of crystalline gramicidin obtained in 1963 was distributed into ampoules in 55 mg amounts and dried in vacuo; the ampoules were then filled with dried nitrogen and sealed. The proposed international reference preparation was assayed biologically against the Master Standard of Gramicidin of the US Food and Drug Administration in 7 laboratories in 6 countries by turbidimetric methods. Significant curvature of the dose—response lines was found for most assays; no single transformation improved the linearity of assays from all laboratories. Although significant heterogeneity of potencies was obtained in 5 laboratories the mean potency ratios for all laboratories only varied over a range of 5% to 6%. The composition of the material is 7% gramicidin B, 50% gramicidin A and 25% gramicidin C; preparations of gramicidin containing appreciably higher concentrations of gramicidin B can be expected to give invalid assays against the international reference preparation. The material has been established as the International Reference Preparation of Gramicidin with a defined potency of 1000 IU/mg. The International Unit of Gramicidin is defined as the activity of 0.001 mg of the International Reference Preparation of Gramicidin. PMID:5299675

  5. Ionosphere over Africa: Results from Geomagnetic Field Measurements During International Heliophysical Year IHY

    NASA Astrophysics Data System (ADS)

    Rabiu, A. B.; Yumoto, K.; Falayi, E. O.; Bello, O. R.; Magdas/Cpmn Group

    2011-12-01

    Space Environment Research Centre of Kyushu University, Japan, installed 13 units of Magnetic Data Acquisition Systems MAGDAS over Africa during the International Heliophysical Year IHY. Magnetic records from 10 stations along the African 96o Magnetic Meridian (Geographical 30° - 40° East) were examined for Solar quiet daily Sq variations in the two geomagnetic field components H and D. Latitudinal variations of Sq in the geomagnetic components were examined. Signatures of equatorial electrojet and worldwide Sq were identified and studied in detail. H field experienced more variation within the equatorial electrojet zone. Diurnal variations of the geomagnetic variations in the two components were discussed. Sq H is expectedly consistently maximum within the electrojet zone as a result of EEJ. Sq D has maximum values at about -20ɛ (sunrise), -10ɛ (noon time) and +10ɛ (sunset). Levels of inter-relationships between the Sq and its variability in the two components were statistically derived and interpreted in line with the mechanisms responsible for the variations of the geomagnetic field. Data from 2 magnetic observatories within equatorial electrojet EEJ strip and 2 stations outside the EEJ strip were employed to evaluate and study the signatures of the Equatorial electrojet over the African sector. The transient variations of the EEJ at two almost parallel axes using Lagos-Ilorin (West Africa) and Nairobi-Addis Ababa (East Africa) pairs were examined. The eastern electrojet appeared stronger than the western. The latitudinal and longitudinal profiles of the Sq were examined and inferences drawn from observed results were discussed.

  6. New idea of geomagnetic monitoring through ENA detection from the International Space Station: ENAMISS project

    NASA Astrophysics Data System (ADS)

    Milillo, Anna; De Angelis, Elisabetta; Orsini, Stefano; Rubini, Alda; Evangelista, Yuri; Mura, Alessandro; Rispoli, Rosanna; Vertolli, Nello; Carrubba, Elisa; Donati, Alessandro; Di Lellis, Andrea Maria; Plainaki, Christina; Lazzarotto, Francesco

    2016-04-01

    Remote sensing of Energetic Neutral Atoms (ENA) in the Earth's environment has been proven to be a successful technique able to provide detailed information on the ring current plasma population at energies below 100 keV. Indeed, the existing space weather databases usually include a good coverage of Sun and solar wind monitoring. The global imaging of the Earth's magnetosphere/ ionosphere is usually obtained by the high-latitudes monitoring of aurorae, ground magnetic field variations and high-latitude radio emissions. The equatorial magnetic field variations on ground, from which the geomagnetic indices like Dst, Sym-H and Asym-H are derived, include the effects of all current systems (i.e. ring current, Chapman -Ferraro current, tails currents, etc...) providing a kind of global information. Nevertheless, the specific information related to the ring current cannot be easily derived from such indices. Only occasional local plasma data are available by orbiting spacecraft. ENA detection is the only way to globally view the ring current populations. Up-to-now this technique has been used mainly from dedicated high altitude polar orbiting spacecraft, which do not allow a continuous and systematic monitoring, and a discrimination of the particle latitude distribution. The Energetic Neutral Atoms Monitor on the International space Station (ENAMISS) project intends to develop an ENA imager and install it on the ISS for continuous monitoring of the spatially distributed ring current plasma population. ISS is the ideal platform to perform continuous ENA monitoring since its particular low altitude and medium/low latitude orbit allows wide-field ENA images of various magnetospheric regions. The calibrated ENA data, the deconvolved ion distributions and ad-hoc ENA-based new geomagnetic indices will be freely distributed to the space weather community. Furthermore, new services based on plasma circulation models, spacecraft surface charging models and radiation dose models

  7. The use of geomagnetic field models in magnetic surveys

    NASA Technical Reports Server (NTRS)

    Regan, R. D.; Gain, J. C.

    1974-01-01

    The importance of global geomagnetic field models for the reduction of magnetic surveys is discussed. It is demonstrated that a numerical model with adequate secular variation correction, provides a suitable representation of the regional field. The limitations of the presently available models are reported, with emphasis on the International Geomagnetic Reference Field.

  8. The calculation of corrected geomagnetic coordinates in the high latitude region

    NASA Astrophysics Data System (ADS)

    Alperovich, Leonid; Levitin, Anatoly; Gromova, Lyudmila; Dremukhina, Lyudmila

    Because the real geomagnetic field in Space, especially during geomagnetic perturbations has very complex spatial distribution, we had to use adjusted geomagnetic coordinates. The calculation of these coordinates is connected with the correct calculation of field lines inclusive the internal IGRF (International Geomagnetic Reference Field) and external geomagnetic field. Tables of such coordinates are somewhat incorrect as they do not account for the coordinates' dependency on geomagnetic activity dynamics. We demonstrate how the coordinates vary with geomagnetic activity in high latitude regions. The calculations revealed that during magnetic storms in a major part of the near pole area the field lines are disclosed and for points of this area on the earth's surface the corrected geomagnetic coordinates cannot be calculated.

  9. International comparisons to establish the traceability in the global network of geomagnetic observatories to SI units

    NASA Astrophysics Data System (ADS)

    Shifrin, V. Ya; Khorev, V. N.; Rasson, J.; Park, Po Gyu

    2014-01-01

    The international comparisons in the field of earth-level dc magnetic flux density measurements with the participation of six National Metrology Institutes (NMIs) and four geomagnetic observatories (GMOs) have been carried out in 2013 and 2014 under the auspices of the Regional Metrology Organization Asia Pacific Metrology Programme (APMP). The obtained expanded uncertainty (k = 2) of the weighted mean value of correction values does not exceed 0.1 nT in the range of 20 μT to 100 μT, which was one of the main aims of this comparison. VNIIM (D I Mendeleyev Institute for Metrology) was the pilot laboratory for this comparison registered in the Key Comparison Data Base (KCDB) under index APMP.EM-S14. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  10. International linear collider reference design report

    SciTech Connect

    Aarons, G.

    2007-06-22

    The International Linear Collider will give physicists a new cosmic doorway to explore energy regimes beyond the reach of today's accelerators. A proposed electron-positron collider, the ILC will complement the Large Hadron Collider, a proton-proton collider at the European Center for Nuclear Research (CERN) in Geneva, Switzerland, together unlocking some of the deepest mysteries in the universe. With LHC discoveries pointing the way, the ILC -- a true precision machine -- will provide the missing pieces of the puzzle. Consisting of two linear accelerators that face each other, the ILC will hurl some 10 billion electrons and their anti-particles, positrons, toward each other at nearly the speed of light. Superconducting accelerator cavities operating at temperatures near absolute zero give the particles more and more energy until they smash in a blazing crossfire at the centre of the machine. Stretching approximately 35 kilometres in length, the beams collide 14,000 times every second at extremely high energies -- 500 billion-electron-volts (GeV). Each spectacular collision creates an array of new particles that could answer some of the most fundamental questions of all time. The current baseline design allows for an upgrade to a 50-kilometre, 1 trillion-electron-volt (TeV) machine during the second stage of the project. This reference design provides the first detailed technical snapshot of the proposed future electron-positron collider, defining in detail the technical parameters and components that make up each section of the 31-kilometer long accelerator. The report will guide the development of the worldwide R&D program, motivate international industrial studies and serve as the basis for the final engineering design needed to make an official project proposal later this decade.

  11. Kinetic theory of geomagnetic pulsations: I. Internal excitations by energetic particles

    SciTech Connect

    Chen, Liu . Plasma Physics Lab. Princeton Univ., NJ . Dept. of Astrophysical Sciences); Hasegawa, Akira )

    1990-05-01

    Motivated by recent satellite observations, we have carried out a comprehensive theoretical analysis on the generation of hydromagnetic Alfven waves in a realistic magnetospheric plasma environment consisting of a core and an energetic components. Our theoretical formulation employs the gyrokinetic equations and, thus, retains nonuniform plasma equilibria, anisotropy, finite Larmor radii, magnetic trapping as well as wave-particle interactions. A set of coupled equations for transverse and compressional magnetic perturbations is derived and analyzed for its stabilities assuming interchange stable equilibrium distribution functions. Our findings are compressional and tranverse shear Alfven oscillations are generally coupled in realistic plasmas. In the decoupled limit, for the compressional wave branch, one recovers the drift-mirror instability due to the Landau resonances and {tau} {equivalent to} 1 + 4 {pi}({partial derivative}P{sub {perpendicular}}/B{partial derivative}B) < 0. Here, P{sub {perpendicular}} = P{sub {perpendicular}}({psi},B) is the perpendicular pressure and {psi} is the magnetic flux function. For the decoupled transverse shear Alfven branch, one obtains the drift Alfven ballooning instability due to the Landau resonances and free energy of the pressure gradient for {tau} > 0. For both branches, the most unstable modes have antisymmetric structures and propagate in the diamagnetic drift direction of the energetic ions. Finite coupling can be shown to further enhance the drift Alfven ballooning instabilities. Thus, we conclude that for {tau} {ge} 0, the coupled drift Alfven ballooning-mirror instability constitutes an important internal generating mechanism of geomagnetic pulsations. The various predicted features of this instability are also found to be consistent with satellite observations.

  12. Kinetic theory of geomagnetic pulsations 1. Internal excitations by energetic particles

    SciTech Connect

    Liu Chen ); Hasegawa, Akira )

    1991-02-01

    Motivated by recent satellite observations. the authors have carried out a comprehensive theoretical analysis on the generation of hydromagnetic Alfven waves in a realistic magnetospheric plasma environment consisting of a core ({approximately}100 eV) component and an energetic ({approximately}10 keV) component. The theoretical formulation employs the gyrokinetic equations and, thus, retains anisotropy, finite Larmor radii, magnetic trapping, and wave-particle interactions in addition to nonuniform plasma equilibria. A set of coupled equations for transverse and compressional magnetic perturbations is derived and analyzed for its stabilities assuming equilibrium distribution functions which are interchange stable. The findings are as follows: (1) compressional and transverse shear Alfven oscillations are generally coupled in realistic plasmas; (2) in the decoupled limit, for the compressional wave branch, one recovers the drift mirror instability due to the Landau resonances and {tau}{triple bond} 1 + 4{pi}({partial derivative}P{sub {perpendicular}}/B{partial derivative}B) < 0; here, P{sub {perpendicular}}=P{sub {perpendicular}}({psi},B) is the perpendicular pressure and {psi} is the magnetic flux function; (3) for the decoupled transverse shear Alfven branch, one obtains the drift Alfven ballooning instability due to the Landau resonances and free energy of the pressure gradient for {tau} > 0; (4) for both branches, the most unstable modes have antisymmetric structures and propagate in the diamagnetic drift direction of the energetic ions; and (5) finite coupling can be shown to further enhance the drift Alfven ballooning instabilities. Thus they conclude that for {tau}{ge}0, the coupled drift Alfven ballooning mirror instability constitutes an important internal generating mechanism of geomagnetic pulsations. The various predicted features of this instability are consistent with satellite observations.

  13. 75 FR 34017 - International Mail Manual; Incorporation by Reference

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-16

    ... 20 International Mail Manual; Incorporation by Reference AGENCY: Postal Service TM . ACTION: Final... United States Postal Service, International Mail Manual (IMM ) and its incorporation by reference in the...: Issue 36 of the International Mail Manual was issued on May 11, 2009. It replaced all previous...

  14. The International Reference Ionosphere: Model Update 2016

    NASA Astrophysics Data System (ADS)

    Bilitza, Dieter; Altadill, David; Reinisch, Bodo; Galkin, Ivan; Shubin, Valentin; Truhlik, Vladimir

    2016-04-01

    The International Reference Ionosphere (IRI) is recognized as the official standard for the ionosphere (COSPAR, URSI, ISO) and is widely used for a multitude of different applications as evidenced by the many papers in science and engineering journals that acknowledge the use of IRI (e.g., about 11% of all Radio Science papers each year). One of the shortcomings of the model has been the dependence of the F2 peak height modeling on the propagation factor M(3000)F2. With the 2016 version of IRI, two new models will be introduced for hmF2 that were developed directly based on hmF2 measurements by ionosondes [Altadill et al., 2013] and by COSMIC radio occultation [Shubin, 2015], respectively. In addition IRI-2016 will include an improved representation of the ionosphere during the very low solar activities that were reached during the last solar minimum in 2008/2009. This presentation will review these and other improvements that are being implemented with the 2016 version of the IRI model. We will also discuss recent IRI workshops and their findings and results. One of the most exciting new projects is the development of the Real-Time IRI [Galkin et al., 2012]. We will discuss the current status and plans for the future. Altadill, D., S. Magdaleno, J.M. Torta, E. Blanch (2013), Global empirical models of the density peak height and of the equivalent scale height for quiet conditions, Advances in Space Research 52, 1756-1769, doi:10.1016/j.asr.2012.11.018. Galkin, I.A., B.W. Reinisch, X. Huang, and D. Bilitza (2012), Assimilation of GIRO Data into a Real-Time IRI, Radio Science, 47, RS0L07, doi:10.1029/2011RS004952. Shubin V.N. (2015), Global median model of the F2-layer peak height based on ionospheric radio-occultation and ground-based Digisonde observations, Advances in Space Research 56, 916-928, doi:10.1016/j.asr.2015.05.029.

  15. Off median phenomena and international reference ionosphere; COSPAR International Scientific Symposium, Trieste, Italy, Oct. 19-22, 1993

    NASA Technical Reports Server (NTRS)

    Rawer, K. (Editor); Piggott, W. R. (Editor); Paul, A. K. (Editor)

    1995-01-01

    The main subject of the symposium was 'off-median phenomena'. The title denotes a range of problems that are rarely considered in 'pure science' studies of the ionosphere. The appearance of regular ionospheric variations is well known. Most of these depend on evident solar-geophysical influences like day and night, solar zenith angle, the seasons, geomagnetic control, solar activity, etc. Applicants and theoreticians as well used to work with monthly medians so that the in fact existing and quite important day-to-day variability is systematically overlooked. It is evident that a descriptive model like the International Reference Ionosphere (IRI) would be inadequate if this variability were denied. Interesting contributions from the symposium on 'off-median phenomena' and the IRI are presented.

  16. The null magnetic field as reference for the study of geomagnetic directional effects in animals and man.

    NASA Technical Reports Server (NTRS)

    Beischer, D. E.

    1971-01-01

    Techniques for producing very low and zero magnetic fields are considered, giving attention to the compensation of the geomagnetic field by a Helmholtz coil system, approaches utilizing the shielding power of highly permeable alloys, and the complete exclusion of the geomagnetic field with the aid of a superconductive shield. Animal experiments in low magnetic fields are discussed, together with the exposure of man to 'null' magnetic fields and the Josephson junction as a possible biosensor of magnetic fields. It is found that neither the functions nor the behavior of man changes significantly during a two-week exposure to magnetic fields below 50 gammas.

  17. Reference Guide to the International Space Station

    NASA Technical Reports Server (NTRS)

    Kitmacher, Gary H.

    2006-01-01

    The International Space Station (ISS) is a great international, technological, and political achievement. It is the latest step in humankind's quest to explore and live in space. The research done on the ISS may advance our knowledge in various areas of science, enable us to improve life on this planet, and give us the experience and increased understanding that can eventually equip us to journey to other worlds. As a result of the Station s complexity, few understand its configuration, its design and component systems, or the complex operations required in its construction and operation. This book provides high-level insight into the ISS. The ISS is in orbit today, operating with a crew of three. Its assembly will continue through 2010. As the ISS grows, its capabilities will increase, thus requiring a larger crew. Currently, 16 countries are involved in this venture. This CD-ROM includes multimedia files and animations.

  18. 76 FR 50414 - International Mail Manual; Incorporation by Reference

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-15

    ... 20 International Mail Manual; Incorporation by Reference AGENCY: Postal Service\\TM\\. ACTION: Final... Postal Service, International Mail Manual (IMM ) dated April 17, 2011, updated with Postal Bulletin... International Mail Manual was issued on April 17, 2011, and was updated with postal bulletin revisions...

  19. 77 FR 64724 - International Mail Manual; Incorporation by Reference

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-23

    ... 20 International Mail Manual; Incorporation by Reference AGENCY: Postal Service\\TM\\. ACTION: Final... Postal Service, International Mail Manual (IMM ) dated June 24, 2012, updated with Postal Bulletin...: Lizbeth Dobbins, (202) 268-3789. SUPPLEMENTARY INFORMATION: The International Mail Manual was issued...

  20. A model of geomagnetic secular variation for 1980-1983

    USGS Publications Warehouse

    Peddie, N.W.; Zunde, A.K.

    1987-01-01

    We developed an updated model of the secular variation of the main geomagnetic field during 1980 through 1983 based on annual mean values for that interval from 148 worldwide magnetic observatories. The model consists of a series of 80 spherical harmonics, up to and including those of degree and order 8. We used it to form a proposal for the 1985 revision of the International Geomagnetic Reference Field (IGRF). Comparison of the new model, whose mean epoch is approximately 1982.0, with the Provisional Geomagnetic Reference Field for 1975-1980 (PGRF 1975), indicates that the moment of the centered-dipole part of the geomagnetic field is now decreasing faster than it was 5 years ago. The rate (in field units) indicated by PGRF 1975 was about -25 nT a-1, while for the new model it is -28 nT a-1. ?? 1987.

  1. Developing an international Pseudomonas aeruginosa reference panel

    PubMed Central

    De Soyza, Anthony; Hall, Amanda J; Mahenthiralingam, Eshwar; Drevinek, Pavel; Kaca, Wieslaw; Drulis-Kawa, Zuzanna; Stoitsova, Stoyanka R; Toth, Veronika; Coenye, Tom; Zlosnik, James E A; Burns, Jane L; Sá-Correia, Isabel; De Vos, Daniel; Pirnay, Jean-Paul; Kidd, Timothy J; Reid, David; Manos, Jim; Klockgether, Jens; Wiehlmann, Lutz; Tümmler, Burkhard; McClean, Siobhán; Winstanley, Craig

    2013-01-01

    Pseudomonas aeruginosa is a major opportunistic pathogen in cystic fibrosis (CF) patients and causes a wide range of infections among other susceptible populations. Its inherent resistance to many antimicrobials also makes it difficult to treat infections with this pathogen. Recent evidence has highlighted the diversity of this species, yet despite this, the majority of studies on virulence and pathogenesis focus on a small number of strains. There is a pressing need for a P. aeruginosa reference panel to harmonize and coordinate the collective efforts of the P. aeruginosa research community. We have collated a panel of 43 P. aeruginosa strains that reflects the organism's diversity. In addition to the commonly studied clones, this panel includes transmissible strains, sequential CF isolates, strains with specific virulence characteristics, and strains that represent serotype, genotype or geographic diversity. This focussed panel of P. aeruginosa isolates will help accelerate and consolidate the discovery of virulence determinants, improve our understanding of the pathogenesis of infections caused by this pathogen, and provide the community with a valuable resource for the testing of novel therapeutic agents. PMID:24214409

  2. International Relations: A Student's Guide to Reference Resources.

    ERIC Educational Resources Information Center

    Silvester, Elizabeth

    Intended for students, this annotated bibliography describes reference materials in International Relations that may be found in either the McLennan or Law Library of McGill University. Scope includes political science, international law, and related areas in the social and behavioral sciences, but titles which relate to the foreign relations of a…

  3. Preface: International Reference Ionosphere and Global Navigation Satellite Systems

    NASA Astrophysics Data System (ADS)

    Bilitza, Dieter; Reinisch, Bodo

    2015-04-01

    The International Reference Ionosphere (IRI) is a joint undertaking by the Committee on Space Research (COSPAR) and the International Union of Radio Science (URSI) with the goal of developing and improving an international standard for the specification of Earth's ionosphere. This endeavor was originally triggered by the need for an ionosphere model for the satellite/experiment design and satellite data analysis (COSPAR) and for radio propagation studies (URSI) but has meanwhile found a much broader range of users with space weather concerns.

  4. Evolution of Consistency Between Eop Series and International Reference

    NASA Astrophysics Data System (ADS)

    Bizouard, C.; Gambis, D.

    One fundamental problem associated with EOP series collected by IERS EOP- Prod- uct Center (the former Central Bureau of the IERS of Paris Observatory) is their consistency with the International Celestial Reference Frame (ICRF) and the Inter- national Terrestrial Reference Frame (ITRF). Individual EOP series are referred to frames which can present some small rotations with respect to ICRF and ITRF. From the knowledge of these rotations it is possible to infer the biais of these series with re- spect to the combined reference series C04, which are referred to the ICRF and ITRF. The consistency is defined, for each EOP, by the offset between this theoretical biais and the real one. We present the evolution of consistency from 1988 (the creation of IERS) to 2001 for VLBI, LLR, SLR and GPS series. We show the progress which has been achieved, and we focuse on the new challenges.

  5. A Proposed International Tropical Reference Atmosphere up to 80 Km

    NASA Technical Reports Server (NTRS)

    Ananthasayanam, M. R.; Narasimha, R.

    1985-01-01

    Based upon previous standard reference atmosphere, which are usually inspired by temperature regions, a proposal is made for an International Tropical Reference Atmosphere (ITRA). It is a modification of the Indian Standard Tropical Atmosphere (ISIA). The data at the available longitudinal stations in the tropics was considered in formulating the present proposal. Balloonsonde, rocketsonde, and grenade and falling sphere data was used in developing the temperature data bse fromt he stratosphere, troposphere and mesosphere. Temperature distribution and mean sea level pressures up to 80 km altitudes is discussed.

  6. Geomagnetism applications

    USGS Publications Warehouse

    Campbell, Wallace H.

    1995-01-01

    The social uses of geomagnetism include the physics of the space environment, satellite damage, pipeline corrosion, electric power-grid failure, communication interference, global positioning disruption, mineral-resource detection, interpretation of the Earth's formation and structure, navigation, weather, and magnetoreception in organisms. The need for continuing observations of the geomagnetic field, together with careful archiving of these records and mechanisms for dissemination of these data, is emphasized.

  7. Construction of Taiwanese Adult Reference Phantoms for Internal Dose Evaluation.

    PubMed

    Chang, Shu-Jun; Hung, Shih-Yen; Liu, Yan-Lin; Jiang, Shiang-Huei

    2016-01-01

    In the internal dose evaluation, the specific absorbed fraction (SAF) and S-value are calculated from the reference phantom based on Caucasian data. The differences in height and weight between Caucasian and Asian may lead to inaccurate dose estimation. In this study, we developed the Taiwanese reference phantoms. 40 volunteers were recruited. Magnetic resonance images (MRI) were obtained, and the contours of 15 organs were drawn. The Taiwanese reference man (TRM) and Taiwanese reference woman (TRW) were constructed. For the SAF calculation, the differences in the self-absorption SAF (self-SAF) between the TRM, TRW, and Oak Ridge National Laboratory (ORNL) adult phantom were less than 10% when the difference in organ mass was less than 20%. The average SAF from liver to pancreas of TRM was 38% larger than that of the ORNL adult phantom, and the result of TRW was 2.02 times higher than that of the ORNL adult phantom. For the S-value calculation, the ratios of TRW and ORNL adult phantom ranged from 0.91 to 1.57, and the ratios of TRM and ORNL adult phantom ranged from 1.04 to 2.29. The SAF and S-value results were dominantly affected by the height, weight, organ mass, and geometric relationship between organs. By using the TRM and TRW, the accuracy of internal dose evaluation can be increased for radiation protection and nuclear medicine. PMID:27618708

  8. Observed Coupling Between the International Space Station PCU Plasma and a FPMU Langmuir Probe Facilitated by the Geomagnetic Field

    NASA Technical Reports Server (NTRS)

    Hartman, William; Koontz, Steven L.

    2010-01-01

    Electrical charging of the International Space Station (ISS) is a matter of serious concern resulting from the possibility of vehicle arcing and electrical shock hazard to crew during extravehicular activity (EVA). A Plasma Contactor Unit (PCU) was developed and integrated into ISS in order to control the ISS floating potential, thereby, minimize vehicle charging and associated hazards. One of the principle factors affecting ISS electrical charging is the ionosphere plasma state (i.e., electron temperature and density). To support ISS electrical charging studies a Floating Potential Monitoring Unit (FPMU) is also integrated into ISS in order to measure the ionosphere properties using Langmuir probes (LP). The FPMU was located on the Starboard side of ISS. The PCU is located near the center of ISS with its plasma exhaust pointed to port. From its integration on ISS in 2006 through November of 2009, the FPMU data exhibited nominal characteristics during PCU operation. On November 21, 2009 the FPMU was relocated from the Starboard location to a new Port location. After relocation significant enhanced noise was observed in both the LP current-voltage sweeps and the derived electron temperature data. The enhanced noise only occurred when the PCU was in discharge and at unique and repeatable locations of the ISS orbit. The cause of this enhanced noise was investigated. It was found that there is coupling occurring between the PCU plasma and the FPMU LP. In this paper we shall 1) present the on-orbit data and the presence of enhanced noise, 2) demonstrate that the coupling of the PCU plasma and the FPMU measurements is geomagnetically organized, 3) show that coupling of the PCU plasma and the FPMU is primarily due to and driven by particle-wave interaction and 4) show that the ionosphere conditions are adequate for Alfven waves to be generated by the PCU plasma.

  9. The International Reference Ionosphere: Rawer's IRI and its status today

    NASA Astrophysics Data System (ADS)

    Bilitza, D.

    2014-11-01

    When the Committee on Space Research (COSPAR) initiated the International Reference Ionosphere (IRI) project in 1968 it wisely selected K. Rawer as its first Chairperson. With a solid footing and good contacts in both the ground-based and space-based ionospheric communities he was ideally suited to pull together colleagues and data from both communities to help build the first version of the IRI. He assembled a team of 20+ international ionospheric experts in the IRI Working Group and chaired and directed the group from 1968 to 1984. The working group has now grown to 63 members and the IRI model has undergone many revisions as new data became available and new modeling techniques were applied. This paper was presented during a special session of the Kleinheubach Tagung 2013 in honor of K. Rawer's 100th birthday. It will review the current status of the IRI model and project and the international recognition it has achieved. It is quite fitting that this year we not only celebrate K. Rawer's 100th birthday but also the exciting news that his favorite science endeavor, IRI, has been internationally recognized as an ISO (International Standardization Organization) standard. The IRI homepage is at http://irimodel.org.

  10. The 1995 revision of the joint US/UK geomagnetic field models - I. Secular variation

    USGS Publications Warehouse

    Macmillan, S.; Barraclough, D.R.; Quinn, J.M.; Coleman, R.J.

    1997-01-01

    We present the methods used to derive mathematical models of global secular variation of the main geomagnetic field for the period 1985 to 2000. These secular-variation models are used in the construction of the candidate US/UK models for the Definitive Geomagnetic Reference Field at 1990, the International Geomagnetic Reference Field for 1995 to 2000, and the World Magnetic Model for 1995 to 2000 (see paper II, Quinn et al., 1997). The main sources of data for the secular-variation models are geomagnetic observatories and repeat stations. Over the areas devoid of these data secular-variation information is extracted from aeromagnetic and satellite data. We describe how secular variation is predicted up to the year 2000 at the observatories and repeat stations, how the aeromagnetic and satellite data are used, and how all the data are combined to produce the required models.

  11. Preface: International Reference Ionosphere - Progress in Ionospheric Modelling

    NASA Technical Reports Server (NTRS)

    Bilitza Dieter; Reinisch, Bodo

    2010-01-01

    The international reference ionosphere (lRI) is the internationally recommended empirical model for the specification of ionospheric parameters supported by the Committee on Space Research (COSPAR) and the International Union of Radio Science (URSI) and recognized by the International Standardization Organization (ISO). IRI is being continually improved by a team of international experts as new data become available and better models are being developed. This issue chronicles the latest phase of model updates as reported during two IRI-related meetings. The first was a special session during the Scientific Assembly of the Committee of Space Research (COSPAR) in Montreal, Canada in July 2008 and the second was an IRI Task Force Activity at the US Air Force Academy in Colorado Springs in May 2009. This work led to several improvements and additions of the model which will be included in the next version, IRI-201O. The issue is divided into three sections focusing on the improvements made in the topside ionosphere, the F-peak, and the lower ionosphere, respectively. This issue would not have been possible without the reviewing efforts of many individuals. Each paper was reviewed by two referees. We thankfully acknowledge the contribution to this issue made by the following reviewers: Jacob Adeniyi, David Altadill, Eduardo Araujo, Feza Arikan, Dieter Bilitza, Jilijana Cander, Bela Fejer, Tamara Gulyaeva, Manuel Hermindez-Pajares, Ivan Kutiev, John MacDougal, Leo McNamara, Bruno Nava, Olivier Obrou, Elijah Oyeyemi, Vadym Paznukhov, Bodo Reinisch, John Retterer, Phil Richards, Gary Sales, J.H. Sastri, Ludger Scherliess, Iwona Stanislavska, Stamir Stankov, Shin-Yi Su, Manlian Zhang, Y ongliang Zhang, and Irina Zakharenkova. We are grateful to Peggy Ann Shea for her final review and guidance as the editor-in-chief for special issues of Advances in Space Research. We thank the authors for their timely submission and their quick response to the reviewer comments and humbly

  12. The End of the International Reference Pricing System?

    PubMed

    Persson, Ulf; Jönsson, Bengt

    2016-02-01

    All 28 EU member states except Sweden and the UK apply international reference pricing (IRP), international price comparison, external reference pricing or cross-reference pricing. The attractiveness of using prices of other countries as a benchmark for decisions within a national price control is obvious. Alternative models for price and reimbursement decision making such as value-based pricing (VBP), i.e. cost-effectiveness analyses, are more complicated. However, IRP provides incentives for stakeholders to take action not in line with optimal (welfare-maximizing) pricing. IRP is costly for two reasons. First, manufacturers are incentivised to limit or delay access to new innovative treatments in countries with small markets and/or a low income, which can be costly in terms of loss of health. Second, all countries also experience a loss of welfare (health) because IRP reduces the opportunities for differential pricing (Ramsey pricing), i.e. using the fact that the ability and willingness to pay differs between countries. Thus, IRP results in less sales revenue to finance research and development of new innovative drugs. We can now observe that payers and manufacturers are engaged in different types of risk-sharing schemes, price-volume negotiations, payback arrangements, confidential discounts, coverage with evidence developments, etc., all with the purpose of returning to the old model of price discrimination and Ramsey pricing. Shortly, real prices for use in IRP systems will cease to exist and, thus, we expect to soon see the end of IRP, a new system for price discrimination and an increasing demand for VBP. PMID:26112982

  13. Realization of the International Celestial Reference Frame from VLBI Astrometry

    NASA Astrophysics Data System (ADS)

    Ma, C.

    1997-12-01

    The International Celestial Reference Frame (ICRF) has now been realized with compact extragalactic objects whose radio-frequency positions are measured at the submilliarcsecond level by VLBI (Very Long Baseline Interferometry). The ICRF replaces the FK5 as the defining realization of the celestial reference system as of 1 Jan 1998 according the resolution adopted by the IAU General Assembly in Kyoto. The ICRF catalog includes 212 defining sources, 294 candidate sources, and 102 other sources, the sum uniformly populating the celestial sphere. The majority are quasars with compact cores and many have optical counterparts. Because of the nature of the VLBI observations (precise angular measurements over a large portion of the sky in a 24-hr interval) and the absence of measurable real transverse motion of the objects, the ICRF can be constructed rigidly and with great precision using data of considerable temporal and geographic extent. The positions and uncertainties, typically <0.5 mas, represent the distillation of 1.6 million dual-frequency Mark III VLBI delay and delay rate observations acquired between August 1979 and July 1995 from various geodetic and astrometric observing programs using radio observatories on every continent. Following IAU resolutions, individual ICRF positions will evolve as more observations and improved models become available, but the orientation (axes) of the ICRF will be maintained by a statistical no-net-rotation condition between the catalog positions of successive realizations. Celestial positions are no longer referred to a system associated with the equator or the ecliptic. Further information about the ICRF can be found in Technical Note 23 of the International Earth Rotation Service.

  14. Evidence for a New Geomagnetic Jerk in 2014

    NASA Astrophysics Data System (ADS)

    Pavón-Carrasco, F. J.; Torta, J. M.; Marsal, S.; Finlay, C. C.

    2015-12-01

    The production of quasi-definitive data at an observatory has enabled us to detect a new geomagnetic jerk in 2014. The jerk has been confirmed by inspecting recent direct observations of the development of the time derivative of the field elements at several other geomagnetic observatories. Its characteristics are similar to those reported for previous jerks, though on this occasion the change in the secular variation slope in Europe almost equals that experienced at the Africa-Atlantic observatories. A global model produced with the latest available satellite and observatory data supports these findings, giving a global perspective on both the jerk and a related secular acceleration pulse at the core-mantle boundary. Should the present field variation persist, predictions from models produced with data only up until the epoch during which the jerk occurred, such as the 12th generation International Geomagnetic Reference Field, might be poorer than expected in the upcoming years.

  15. Magnetospheric effects of cosmic rays. 1. Long-term changes in the geomagnetic cutoff rigidities for the stations of the global network of neutron monitors

    NASA Astrophysics Data System (ADS)

    Gvozdevskii, B. B.; Abunin, A. A.; Kobelev, P. G.; Gushchina, R. T.; Belov, A. V.; Eroshenko, E. A.; Yanke, V. G.

    2016-07-01

    Vertical geomagnetic cutoff rigidities are obtained for the stations of the global network of neutron monitors via trajectory calculations for each year of the period from 1950 to 2020. Geomagnetic cutoff rigidities are found from the model of the Earth's main field International Geomagnetic Reference Field (IGRF) for 1950-2015, and the forecast until 2020 is provided. In addition, the geomagnetic cutoff rigidities for the same period are obtained by Tsyganenko model T89 (Tsyganenko, 1989) with the average annual values of the Kp-index. In each case, the penumbra is taken into account in the approximation of the flat and power spectra of variations of cosmic rays. The calculation results show an overall decrease in geomagnetic cutoff rigidities, which is associated with the overall decrease and restructuring of the geomagnetic field during the reporting period, at almost all points.

  16. AOAC INTERNATIONAL's Technical Division on Reference Materials (TDRM) Reference Materials Database.

    PubMed

    Zink, Donna

    2016-09-01

    The Technical Division on Reference Materials (TDRM) of AOAC INTERNATIONAL recommends policy and criteria to facilitate the development and use of reference materials (RMs) in the validation, implementation, and routine use of AOAC INTERNATIONAL methods. To aid analysts in these areas, TDRM has developed a searchable online database to identify RMs suitable for use with AOAC Official Methods of Analysis(SM) (OMA). RMs can be queried by analyte, by analyte and matrix, or by the selection of an OMA, based on analytes and matrixes described within the scope of the selected method. Only essential information is included in the database, to maximize usefulness and minimize the effort required to keep information current. Additional information, such as measurement uncertainty and purchasing instructions, is available through a link to the producer's Web site, when that information is available online. Data sets are solicited on a voluntary basis from National Metrology Institutes and accredited producers. Consideration of ease-of-use and ease-of-operation is a guiding principle in this database, as is cost management. PMID:27619655

  17. International collaborative assay of the International Reference Preparation of Anti-Yellow-Fever Serum

    PubMed Central

    Krag, P.; MacNamara, F. N.; Lyng, J.; Bentzon, M. Weis; Larsen, S. Olesen

    1965-01-01

    A yellow fever immune serum was established in 1962 by the WHO Expert Committee on Biological Standardization as the International Reference Preparation of Anti-Yellow-Fever Serum, intended to serve as an immune reference serum in the mouse protection test used in the control of yellow fever vaccines. Before its establishment as the International Reference Preparation, the proposed material was assayed in eleven laboratories in ten countries against a number of other immune and non-immune sera, and was found stable. Neutralization test results were consistent and the relative potency was sufficiently high. This paper not only reports on the collaborative assay, but also discusses errors in the testing method and problems connected with the distribution of mouse deaths during the observation period and with the preparation of dilutions. PMID:5294595

  18. The International Reference Ionosphere Today and in the Future

    NASA Technical Reports Server (NTRS)

    Bilitza, Dieter; McKinnell, Lee-Ane; Reinisch, Bodo; Fuller-Rowell,Tim

    2010-01-01

    The international reference ionosphere (IRI) is the internationally recognized and recommended standard for the specification of plasma parameters in Earth's ionosphere. It describes monthly averages of electron density, electron temperature, ion temperature, ion composition, and several additional parameters in the altitude range from 60 to 1,500 km. A joint working group of the Committee on Space Research (COSPAR) and the International Union of Radio Science (URSI) is in charge of developing and improving the IRI model. As requested by COSPAR and URSI, IRI is an empirical model being based on most of the available and reliable data sources for the ionospheric plasma. The paper describes the latest version of the model and reviews efforts towards future improvements, including the development of new global models for the F2 peak density and height, and a new approach to describe the electron density in the topside and plasmasphere. Our emphasis will be on the electron density because it is the IRI parameter most relevant to geodetic techniques and studies. Annual IRI meetings are the main venue for the discussion of IRI activities, future improvements, and additions to the model. A new special IRI task force activity is focusing on the development of a real-time IRI (RT-IRI) by combining data assimilation techniques with the IRI model. A first RT-IRI task force meeting was held in 2009 in Colorado Springs. We will review the outcome of this meeting and the plans for the future. The IRI homepage is at http://www.IRI.gsfc.nasa.gov

  19. Worldwide Geomagnetic Data Collection and Management

    NASA Astrophysics Data System (ADS)

    Mandea, Mioara; Papitashvili, Vladimir

    2009-11-01

    Geomagnetic data provided by different platforms piece together a global picture of Earth's magnetic field and its interaction with geospace. Furthermore, a great diversity of the geomagnetic field changes, from secular (over decades to centuries) to short time variations (down to minutes and seconds), can be detected only through continued observations. An international effort to watch and record geomagnetic changes first began in the 1830s with a network of scientific observers organized by Karl Friedrich Gauss in Germany, and this effort has continued since then. One of the most remarkable achievements in understanding the geomagnetic field morphology and time behavior was made possible by the International Geophysical Year (IGY), an exploration and research effort that lasted for 18 months, starting on 1 July 1957. The IGY encompassed 11 geoscience disciplines, including geomagnetism. The IGY has represented a giant step forward in the quality and quantity of worldwide geomagnetic measurements, as well as in the widespread interest in magnetic measurements. A half century of probing the geomagnetic field spatial and temporal variations has produced a number of outstanding results, and the interested reader can find recent reviews on various geomagnetic field topics (from measurements to modeling) in Encyclopedia of Geomagnetism and Paleomagnetism [Gubbins and Herrero-Bervera, 2007] or Treatise on Geophysics: Geomagnetism [Kono, 2007].

  20. 39 CFR 20.1 - International Mail Manual; incorporation by reference.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... incorporation by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. (b) The current Issue of the... reference. 20.1 Section 20.1 Postal Service UNITED STATES POSTAL SERVICE INTERNATIONAL MAIL INTERNATIONAL POSTAL SERVICE § 20.1 International Mail Manual; incorporation by reference. (a) Section 552(a) of...

  1. 39 CFR 20.1 - International Mail Manual; incorporation by reference.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... incorporation by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. (b) The current Issue of the... reference. 20.1 Section 20.1 Postal Service UNITED STATES POSTAL SERVICE INTERNATIONAL MAIL INTERNATIONAL POSTAL SERVICE § 20.1 International Mail Manual; incorporation by reference. (a) Section 552(a) of...

  2. Mathematical modelling of the geomagnetic field and secular variation, and its applications; Proceedings of the Symposium, Hamburg, West Germany, August 15-27, 1983

    NASA Astrophysics Data System (ADS)

    Barraclough, D. R.

    1985-01-01

    Some of the topics discussed include: the assessment of near-surface accuracy of the International Geomagnetic Reference Field (IGRF 80) model of the main geomagnetic field; application of the IGRF 80 to large sets of marine magnetometer data; and the sensitivity of cosmic ray trajectory calculations to geomagnetic field model representations. Consideration is also given to: a test of main IGRF 80 main field and secular variation in Europe; the perpendicular error effect in DGRF model proposals; a comparison of planetary reference fields over Italy; and the characteristics of secular variation of the geomagnetic field from 1964-1981 in Romania. Some additional topics include: the characteristics of the geomagnetic field and its secular variation in and near China in the past 20 years; the effects of the nonuniform distribution of magnetic observatory data on secular variation models; and earth magnetic field modeling and its relation to geological evolution and structure.

  3. Internal dosimetry estimates using voxelized reference phantoms for thyroid agents

    PubMed Central

    Hoseinian-Azghadi, E.; Rafat-Motavalli, L.; Miri-Hakimabad, H.

    2014-01-01

    This work presents internal dosimetry estimates for diagnostic procedures performed for thyroid disorders by relevant radiopharmaceuticals. The organ doses for 131Iodine, 123Iodine and 99mTc incorporated into the body were calculated for the International Commission on Radiological Protection (ICRP) reference voxel phantoms using the Monte Carlo transport method. A comparison between different thyroid uptakes of iodine in the range of 0–55% was made, and the effect of various techniques for administration of 99mTc on organ doses was studied. To investigate the necessity of calculating organ dose from all source regions, the major source organ and its contribution to total dose were specified for each target organ. Moreover, we compared effective dose in ICRP voxel phantoms with that in stylized phantoms. In our method, we directly calculated the organ dose without using the S values or SAFs, as is commonly done. Hence, a distribution of the absorbed dose to entire tissues was obtained. The chord length distributions (CLDs) were also computed for the selected source–target pairs to make comparison across the genders. The results showed that the S values for radionuclides in the thyroid are not sufficient for calculating the organ doses, especially for 123I and 99mTc. The thyroid and its neighboring organs receive a greater dose as thyroid uptake increases. Our comparisons also revealed an underestimation of organ doses reported for the stylized phantoms compared with the values based on the ICRP voxel phantoms in the uptake range of 5–55%, and an overestimation of absorbed dose by up to 2-fold for Iodine administration using blocking agent and for 99mTc incorporation. PMID:24222311

  4. Transportation of reagents, reference materials and samples: the international perspective.

    PubMed

    Pearson, J E; Edwards, S

    2006-01-01

    The International Regulations for the transport of infectious substances, which could include reagents, reference material and samples, are based on the 13th revision of the United Nations Model Regulations and are the standard for transport of infectious substances by all means of transportation. The 13th revision, effective January 2005 and further amended in March and July 2005, made major improvements in these shipping regulations. They specifically exempt certain substances, including those that have been neutralized or inactivated to destroy any pathogens and samples from "normal" animals. Infectious substances are divided into Category A, which includes primarily cultures of the more pathogenic agents and Category B, which includes all other substances that do not meet the Category A criteria. Tissue specimens, submitted for diagnosis, are included in Category B. Category A shipments must have a Dangerous Goods Certificate and meet other requirements; Category B shipments do not. The National requirements, such as import permits, and certain airline restrictions must also be met. PMID:17058481

  5. Rigorous compilation of the Northern International Reference Stars

    SciTech Connect

    Cole, C.S.

    1986-01-01

    The tabular method of determining the systematic differences between two star catalogues is discussed. It is noted that the tabular method is subjective in nature and that the estimation of the model parameters does not use all available model constraints. Furthermore, these estimates are not least squares estimates, nor are they unbiased. The simultaneous estimation of both target parameters and model parameters is applied to the compilation of a complete star catalogue. By simultaneously using all available constraints on all available data, more precise estimates for the target parameters are obtained. The input material of the Northern International Reference Stars (NIRS) is used and the resulting catalogue is compared to the NIRS catalogue compiled by Corbin in 1982 using standard techniques. It is shown that the new estimates of the star parameters have smaller formal errors than estimates derived from the same material but using conventional procedures. Both versions of the NIRS are used to predict the star positions of the later observed Perth 70: A Catalogue of Positions of 24,900 Stars and these predicted positions are compared to the actual observed positions.

  6. Comparisons of geomagnetic transmission measurements with modified Tsyganenko 1989 model calculations for the October 1989 Solar Energetic Particle events

    NASA Astrophysics Data System (ADS)

    Boberg, P. R.; Smart, D. F.; Shea, M. A.; Tylka, A. J.

    2016-01-01

    We have determined eight-second averaged geomagnetic transmissions of 36-80 MeV protons for the large Solar Energetic Particle (SEP) events and geomagnetic activity level variations of October 1989 using measurements from the NOAA-10 and GOES-7 satellites. We have compared the geomagnetic transmission measurements with model calculations employing trajectory tracings through the combined International Geomagnetic Reference Field (IGRF) and Kp/Dst modified 1989 Tsyganenko model. We present threshold geomagnetic transmission geographic latitudes and magnetic latitudes, as well as (a) differences between the measured and calculated threshold geographic latitudes and magnetic latitudes and (b) differences between measured and calculated polar pass durations. We find that for less disturbed geomagnetic activity levels, the measured threshold geomagnetic transmission geographic and magnetic latitudes are typically about 1-1.5° equatorward of the calculated geographic and magnetic latitudes, while for larger geomagnetic activity levels, the measured geographic and magnetic latitudes can be about 1.5° poleward of the calculated geographic and magnetic latitudes. For the eight Kp bins, we also compare the mean measured magnetic latitudes as a function of mean Dst with the mean calculated magnetic latitudes, interpolated to the mean measured Dst values. These comparisons of mean magnetic latitudes illustrate the improvement in the accuracy of the model calculations resulting from employing the actual mean measured Dst values.

  7. The quasi-biennial variation in the geomagnetic field: a global characteristics analysis

    NASA Astrophysics Data System (ADS)

    Ou, Jiaming; Du, Aimin

    2016-04-01

    The periodicity of 1.5-3 years, namely the quasi-biennial oscillation (QBO), has been identified in the solar, geophysical, and atmospheric variability. Sugiura (1976) investigated the observatory annual means over 1900-1970 and confirmed the QBO in the geomagnetic field. At present, studying the quasi-biennial oscillation becomes substantial for separating the internal/external parts in the geomagnetic observations. For the internal field, two typical periodicities, namely the 6-year oscillation in the geomagnetic secular acceleration (SA) and the geomagnetic jerk (occurs in 1-2 years), have close period to the QBO. Recently, a global quasi-biennial fluctuation was identified in the geomagnetic core field model (Silva et al., 2012). Silva et al. speculated this 2.5 years signal to either external source remaining in the core field model or consequence of the methods used to construct the model. As more high-quality data from global observatories are available, it is a good opportunity to characterize the geomagnetic QBO in the global range. In this paper, we investigate the QBO in the observatory monthly geomagnetic field X, Y, and Z components spanning 1985-2010. We employ the observatory hourly means database from the World Data Center for Geomagnetism (WDC) for the investigation. Wavelet analysis is used to detect and identify the QBO, while Fast Fourier Transform (FFT) analysis to obtain the statistics of the QBO. We apply the spherical harmonic analysis on QBO's amplitude, in order to quantify and separate internal and external sources. Three salient periods respectively at 2.9, 2.2, and 1.7 years, are identified in the amplitude spectrum over 1988-2008. The oscillation with the period of ~2.2 years is most prominent in all field components and further studied. In the X component the QBO is attenuated towards the polar regions, while in the Z component the amplitude of QBO increases with increasing of the geomagnetic latitude. At the high latitudes, the QBO

  8. The International Reference Ionosphere - Climatological Standard for the Ionosphere

    NASA Technical Reports Server (NTRS)

    Bilitza, Dieter

    2006-01-01

    The International Reference Ionosphere (IRI) a joint project of URSI and COSPAR is the defacto standard for a climatological specification of ionospheric parameters. IRI is based on a wide range of ground and space data and has been steadily improved since its inception in 1969 with the ever-increasing volume of ionospheric data and with better mathematical descriptions of the observed global and temporal variation patterns. The IRI model has been validated with a large amount of data including data from the most recent ionospheric satellites (KOMPSAT, ROCSAT and TIMED) and data from global network of ionosondes. Several IRI teams are working on specific aspects of the IRI modeling effort including an improved representation of the topside ionosphere with a seamless transition to the plasmasphere, a new effort to represent the global variation of F2 peak parameters using the Neural Network (NN) technique, and the inclusion of several additional parameters in IRI, e.g., spread-F probability and ionospheric variability. Annual IRI workshops are the forum for discussions of these efforts and for all science activities related to IRI as well as applications of the IRI model in engineering and education. In this paper I will present a status report about the IRI effort with special emphasis on the presentations and results from the most recent IRI Workshops (Paris, 2004; Tortosa, 2005) and on the most important ongoing IRI activities. I will discuss the latest version of the IRI model, IRI-2006, highlighting the most recent changes and additions. Finally, the talk will review some of the applications of the IRI model with special emphasis on the use for radiowave propagation studies and communication purposes.

  9. International longitudinal pediatric reference standards for bone mineral content.

    PubMed

    Baxter-Jones, Adam D G; Burrows, Melonie; Bachrach, Laura K; Lloyd, Tom; Petit, Moira; Macdonald, Heather; Mirwald, Robert L; Bailey, Don; McKay, Heather

    2010-01-01

    To render a diagnosis pediatricians rely upon reference standards for bone mineral density or bone mineral content, which are based on cross-sectional data from a relatively small sample of children. These standards are unable to adequately represent growth in a diverse pediatric population. Thus, the goal of this study was to develop sex and site-specific standards for BMC using longitudinal data collected from four international sites in Canada and the United States. Data from four studies were combined; Saskatchewan Paediatric Bone Mineral Accrual Study (n=251), UBC Healthy Bones Study (n=382); Penn State Young Women's Health Study (n=112) and Stanford's Bone Mineral Accretion study (n=423). Males and females (8 to 25 years) were measured for whole body (WB), total proximal femur (PF), femoral neck (FN) and lumbar spine (LS) BMC (g). Data were analyzed using random effects models. Bland-Altman was used to investigate agreement between predicted and actual data. Age, height, weight and ethnicity independently predicted BMC accrual across sites (P<0.05). Compared to White males, Asian males had 31.8 (6.8) g less WB BMC accrual; Hispanic 75.4 (28.2) g less BMC accrual; Blacks 82.8 (26.3) g more BMC accrual with confounders of age, height and weight controlled. We report similar findings for the PF and FN. Models for females for all sites were similar with age, height and weight as independent significant predictors of BMC accrual (P<0.05). We provide a tool to calculate a child's BMC Z-score, accounting for age, size, sex and ethnicity. In conclusion, when interpreting BMC in pediatrics we recommend standards that are sex, age, size and ethnic specific. PMID:19854308

  10. Non-singular spherical harmonic expressions of geomagnetic vector and gradient tensor fields in the local north-oriented reference frame

    NASA Astrophysics Data System (ADS)

    Du, J.; Chen, C.; Lesur, V.; Wang, L.

    2015-07-01

    General expressions of magnetic vector (MV) and magnetic gradient tensor (MGT) in terms of the first- and second-order derivatives of spherical harmonics at different degrees/orders are relatively complicated and singular at the poles. In this paper, we derived alternative non-singular expressions for the MV, the MGT and also the third-order partial derivatives of the magnetic potential field in the local north-oriented reference frame. Using our newly derived formulae, the magnetic potential, vector and gradient tensor fields and also the third-order partial derivatives of the magnetic potential field at an altitude of 300 km are calculated based on a global lithospheric magnetic field model GRIMM_L120 (GFZ Reference Internal Magnetic Model, version 0.0) with spherical harmonic degrees 16-90. The corresponding results at the poles are discussed and the validity of the derived formulas is verified using the Laplace equation of the magnetic potential field.

  11. Probing Geomagnetic Jerks combining Geomagnetic and Earth Rotation Observations (Invited)

    NASA Astrophysics Data System (ADS)

    Holme, R. T.; de Viron, O.

    2013-12-01

    Geomagnetic jerks, first observed in the late 1970s, are the most rapid variations in the observed geomagnetic field that are believed to be of internal origin. Their occurence has been correlated with a number of different geophysical phenomena. Here we consider simultaneous features in variations in Earth's length of day. Recently, we have provided a simple description of non-atmospheric variations in length of day (LOD), consisting of 3 components: a slowly varying decadal trend, a 5.9-year oscillation, and occasional sudden jumps. Both of the shorter period parts of this correlate with geomagnetic jerks, with peaks in the LOD oscillation being contemporaneous with well-known jerk occurances (for example in 1969, 1972, 1978 and 1982), and jumps in the LOD fitting a jerk observed in satellite data in 2003.5. The simultaneous observation of these two features constrains Earth structure, in particular limiting the electric conductivity of the deep mantle. However, the nature of the LOD changes also may change the paradigm for the study of jerk timings. it is customarily assumed that the jerks represent features in the geomagnetic field that are continuous in the secular variation, but discontinuous in its derivative, the secular acceleration. However, a jump in LOD suggested by the modelling of the data would correspond also to a jump in SV, thus invalidating standard methods for temporal location of a jerk (which will consider the intersection of best-fit straight lines to the secular variation before and after). Olsen and Mandea have localised a jerk in satellite virtual observatory data using flow modelling; this seems the most promising method to investigate whether jerks could have discontinuous secular variation. We apply similar methods to time series of virtual geomagnetic obseratories from satellite data to further explore geomagnetic jerks and their rotational links in the geomagnetic satellite era.

  12. Restoration project of geomagnetic survey in Latvia

    NASA Astrophysics Data System (ADS)

    Burlakovs, J.; Lembere, I.

    2003-04-01

    framework of international projects, e.g. IMAGE and INTERMAGNET; it will be important step towards the geomagnetic observation network development in Europe.

  13. The national geomagnetic initiative

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The Earth's magnetic field, through its variability over a spectrum of spatial and temporal scales, contains fundamental information on the solid Earth and geospace environment (the latter comprising the atmosphere, ionosphere, and magnetosphere). Integrated studies of the geomagnetic field have the potential to address a wide range of important processes in the deep mantle and core, asthenosphere, lithosphere, oceans, and the solar-terrestrial environment. These studies have direct applications to important societal problems, including resource assessment and exploration, natural hazard mitigation, safe navigation, and the maintenance and survivability of communications and power systems on the ground and in space. Studies of the Earth's magnetic field are supported by a variety of federal and state agencies as well as by private industry. Both basic and applied research is presently supported by several federal agencies, including the National Science Foundation (NSF), U.S. Geological Survey (USGS), U.S. Department of Energy (DOE), National Oceanic and Atmospheric Administration (NOAA), National Aeronautics and Space Administration (NASA), and U.S. Department of Defense (DOD) (through the Navy, Air Force, and Defense Mapping Agency). Although each agency has a unique, well-defined mission in geomagnetic studies, many areas of interest overlap. For example, NASA, the Navy, and USGS collaborate closely in the development of main field reference models. NASA, NSF, and the Air Force collaborate in space physics. These interagency linkages need to be strengthened. Over the past decade, new opportunities for fundamental advances in geomagnetic research have emerged as a result of three factors: well-posed, first-order scientific questions; increased interrelation of research activities dealing with geomagnetic phenomena; and recent developments in technology. These new opportunities can be exploited through a national geomagnetic initiative to define objectives and

  14. 39 CFR 20.1 - International Mail Manual; incorporation by reference.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... reference in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. (b) The current Issue of the IMM is... 39 Postal Service 1 2014-07-01 2014-07-01 false International Mail Manual; incorporation by reference. 20.1 Section 20.1 Postal Service UNITED STATES POSTAL SERVICE INTERNATIONAL MAIL...

  15. UFOs, NGOs, or IGOs: Using International Documents for General Reference.

    ERIC Educational Resources Information Center

    Shreve, Catherine

    1997-01-01

    Discusses accessing and using documents from international (intergovernmental) organizations. Profiles the United Nations, the European Union and other Intergovernmental Organizations (IGOs). Discusses the librarian as "Web detective," notes questions to focus on, and presents examples to demonstrate navigation of IGO sites. Lists basic tools for…

  16. Incorporation of geomagnetic data and services into EPOS infrastructure

    NASA Astrophysics Data System (ADS)

    Hejda, Pavel; Chambodut, Aude; Curto, Juan-Jose; Flower, Simon; Kozlovskaya, Elena; Kubašta, Petr; Matzka, Jürgen; Tanskanen, Eija; Thomson, Alan

    2016-04-01

    Monitoring of the geomagnetic field has a long history across Europe that dates back to 1830', and is currently experiencing an increased interest within Earth observation and space weather monitoring. Our goals within EPOS-IP are to consolidate the community, modernise data archival and distribution formats for existing services and create new services for magnetotelluric data and geomagnetic models. Specific objectives are: • Enhance existing services providing geomagnetic data (INTERMAGNET- INTErnational Real-time MAGnetic observatory NETwork; World Data Centre for Geomagnetism; IMAGE- International Monitor for Auroral Geomagnetic Effects) and existing services providing geomagnetic indices (ISGI - International Service of Geomagnetic Indices). • Develop and enhance the geomagnetic community's metadata systems by creating a metadata database, filling it and putting in place processes to ensure that it is kept up to date in the future. • Develop and build access to magnetotelluric (MT) data including transfer functions and time series data from temporary, portable MT-arrays in Europe, as well as to lithospheric conductivity models derived from TM-data. • Develop common web and database access points to global and regional geomagnetic field and conductivity models. • Establish links from the geomagnetic data services, products and models to the Integrated Core Services. The immediate task in the current period is to identify data models of existing services, modify them and integrate into a common model of Geomagnetic Thematic Core Services.

  17. Geomagnetic transmission disturbances and heavy-ion fluences observed in low Earth orbit during the solar energetic particle events of October 1989

    NASA Technical Reports Server (NTRS)

    Boberg, P. R.; Tylka, A. J.; Adams, J. H., Jr.; Beahm, L. P.; Fluckiger, E. O.; Kleis, T.; Kobel, E.

    1996-01-01

    The large solar energetic particle (SEP) events and simultaneous large geomagnetic disturbances observed during October 1989 posed a significant, rapidly evolving space radiation hazard. Using data from the GOES-7, NOAA-10, IMP-8 and LDEF satellites, we determined the geomagnetic transmission, heavy ion fluences, mean Fe ionic charge state, and effective radiation hazard observed in low Earth orbit (LEO) for these SEPs. We modeled the geomagneitc transmission by tracing particles through the combination to the internal International Geomagnetic Reference Field (IGRF) and the Tsyganenko (1989) magnetospheric field models, extending the modeling to large geomagnetic disturbances. We used our results to assess the radiation hazard such very large SEP events would pose in the anticipated 52 deg inclination space station orbit.

  18. High-temperature potentiometric oxygen sensor with internal reference

    DOEpatents

    Routbort, Jules L.; Singh, Dileep; Dutta, Prabir K.; Ramasamy, Ramamoorthy; Spirig, John V.; Akbar, Sheikh

    2011-11-15

    A compact oxygen sensor is provided, comprising a mixture of metal and metal oxide an enclosure containing said mixture, said enclosure capable of isolating said mixture from an environment external of said enclosure, and a first wire having a first end residing within the enclosure and having a second end exposed to the environment. Also provided is a method for the fabrication of an oxygen sensor, the method comprising confining a metal-metal oxide solid mixture to a container which consists of a single material permeable to oxygen ions, supplying an electrical conductor having a first end and a second end, whereby the first end resides inside the container as a reference (PO.sub.2).sup.ref, and the second end resides outside the container in the atmosphere where oxygen partial pressure (PO.sub.2).sup.ext is to be measured, and sealing the container with additional single material such that grain boundary sliding occurs between grains of the single material and grains of the additional single material.

  19. International Reference Ionosphere (IRI): Task Force Activity 2000

    NASA Technical Reports Server (NTRS)

    Bilitza, D.

    2000-01-01

    The annual IRI Task Force Activity was held at the Abdus Salam International Center for Theoretical Physics in Trieste, Italy from July 10 to July 14. The participants included J. Adeniyi (University of Ilorin, Nigeria), D. Bilitza (NSSDC/RITSS, USA), D. Buresova (Institute of Atmospheric Physics, Czech Republic), B. Forte (ICTP, Italy), R. Leitinger (University of Graz, Austria), B. Nava (ICTP, Italy), M. Mosert (University National Tucuman, Argentina), S. Pulinets (IZMIRAN, Russia), S. Radicella (ICTP, Italy), and B. Reinisch (University of Mass. Lowell, USA). The main topic of this Task Force Activity was the modeling of the topside ionosphere and the development of strategies for modeling of ionospheric variability. Each day during the workshop week the team debated a specific modeling problem in the morning during informal presentations and round table discussions of all participants. Ways of resolving the specific modeling problem were devised and tested in the afternoon in front of the computers of the ICTP Aeronomy and Radiopropagation Laboratory using ICTP s computer networks and internet access.

  20. FENDL: International reference nuclear data library for fusion applications

    NASA Astrophysics Data System (ADS)

    Pashchenko, A. B.; Wienke, H.; Ganesan, S.

    1996-10-01

    The IAEA Nuclear Data Section, in co-operation with several national nuclear data centres and research groups, has created the first version of an internationally available Fusion Evaluated Nuclear Data Library (FENDL-1). The FENDL library has been selected to serve as a comprehensive source of processed and tested nuclear data tailored to the requirements of the engineering design activity (EDA) of the ITER project and other fusion-related development projects. The present version of FENDL consists of the following sublibraries covering the necessary nuclear input for all physics and engineering aspects of the material development, design, operation and safety of the ITER project in its current EDA phase: FENDL/A-1.1: neutron activation cross-sections, selected from different available sources, for 636 nuclides, FENDL/D-1.0: nuclear decay data for 2900 nuclides in ENDF-6 format, FENDL/DS-1.0: neutron activation data for dosimetry by foil activation, FENDL/C-1.0: data for the fusion reactions D(d,n), D(d,p), T(d,n), T(t,2n), He-3(d,p) extracted from ENDF/B-6 and processed, FENDL/E-1.0:data for coupled neutron—photon transport calculations, including a data library for neutron interaction and photon production for 63 elements or isotopes, selected from ENDF/B-6, JENDL-3, or BROND-2, and a photon—atom interaction data library for 34 elements. The benchmark validation of FENDL-1 as required by the customer, i.e. the ITER team, is considered to be a task of high priority in the coming months. The well tested and validated nuclear data libraries in processed form of the FENDL-2 are expected to be ready by mid 1996 for use by the ITER team in the final phase of ITER EDA after extensive benchmarking and integral validation studies in the 1995-1996 period. The FENDL data files can be electronically transferred to users from the IAEA nuclear data section online system through INTERNET. A grand total of 54 (sub)directories with 845 files with total size of about 2

  1. Reference Work with International Students: Making the Most Use of the Neutral Question.

    ERIC Educational Resources Information Center

    de Souza, Yvonne

    1996-01-01

    Discusses reference service to international students, potential miscommunications, and problems with the three kinds of questions in the reference interview. Notes the attributes of the neutral question and describes how librarians can maximize its effectiveness by making a "statement of intent" that provides a comfortable framework for the…

  2. Reference States and Relative Values of Internal Energy, Enthalpy, and Entropy.

    ERIC Educational Resources Information Center

    Fredrickson, A. G.

    1983-01-01

    Discusses two reference states (pure chemical compounds and pure elements at specified condition of temperature and pressure) and the relation between these reference states for internal energy and enthalpy. Problem 5.11 from Modell and Reid's "Thermodynamics and its Applications" (p. 141) is used to apply the ideas discussed. (JN)

  3. 39 CFR 20.1 - International Mail Manual; incorporation by reference.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. (b) The current Issue of the IMM is incorporated by... 39 Postal Service 1 2012-07-01 2012-07-01 false International Mail Manual; incorporation by reference. 20.1 Section 20.1 Postal Service UNITED STATES POSTAL SERVICE INTERNATIONAL MAIL...

  4. Geomagnetic excursions date early hominid migration to China

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Atreyee

    2012-09-01

    Global-scale geomagnetic reversals, which are periods when the direction of Earth's magnetic field flips, leave imprints in magnetic minerals present in sediments. But so do smaller-scale, even local, changes in Earth's magnetic field direction. Paleomagnetists believe that the smaller-scale events represent “failed reversals” and refer to them as “geomagnetic excursions.” Scientists use geomagnetic excursions in sedimentary basins as markers to tie together events of Earth's history across the globe.

  5. F2 region response to geomagnetic disturbances across Indian latitudes: O(1S) dayglow emission

    NASA Astrophysics Data System (ADS)

    Upadhayaya, A. K.; Gupta, Sumedha; Brahmanandam, P. S.

    2016-03-01

    The morphology of ionospheric storms has been investigated across equatorial and low latitudes of Indian region. The deviation in F2 region characteristic parameters (foF2 and h'F) along with modeled green line dayglow emission intensities is examined at equatorial station Thiruvananthapuram (8.5°N, 76.8°E, 0.63°S geomagnetic latitude) and low-latitude station Delhi (28.6°N, 77.2°E,19.2°N geomagnetic latitude) during five geomagnetic storm events. Both positive and negative phases have been noticed in this study. The positive storm phase over equatorial station is found to be more frequent, while the drop in ionization in most of the cases was observed at low-latitude station. It is concluded that the reaction as seen at different ionospheric stations may be quite different during the same storm depending on both the geographic and geomagnetic coordinates of the station, storm intensity, and the storm onset time. Modulation in the F2 layer critical frequency at low and equatorial stations during geomagnetic disturbance of 20-23 November 2003 was caused by the storm-induced changes in O/N2. It is also found that International Reference Ionosphere 2012 model predicts the F2 layer characteristic (foF2 and h'F) parameters at both the low and equatorial stations during disturbed days quite reasonably. A simulative approach in GLOW model developed by Solomon is further used to estimate the changes in the volume emission rate of green line dayglow emission under quiet and strong geomagnetic conditions. It is found that the O(1S) dayglow thermospheric emission peak responds to varying geomagnetic conditions.

  6. 40 CFR Appendix 8 to Subpart A of... - Reference C16-C18 Internal Olefin Drilling Fluid Formulation

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 31 2013-07-01 2013-07-01 false Reference C16-C18 Internal Olefin Drilling Fluid Formulation 8 Appendix 8 to Subpart A of Part 435 Protection of Environment ENVIRONMENTAL...—Reference C16-C18 Internal Olefin Drilling Fluid Formulation The reference C16-C18 internal olefin...

  7. 40 CFR Appendix 8 to Subpart A of... - Reference C16-C18 Internal Olefin Drilling Fluid Formulation

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 31 2012-07-01 2012-07-01 false Reference C16-C18 Internal Olefin Drilling Fluid Formulation 8 Appendix 8 to Subpart A of Part 435 Protection of Environment ENVIRONMENTAL...—Reference C16-C18 Internal Olefin Drilling Fluid Formulation The reference C16-C18 internal olefin...

  8. 40 CFR Appendix 8 to Subpart A of... - Reference C16-C18 Internal Olefin Drilling Fluid Formulation

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 30 2014-07-01 2014-07-01 false Reference C16-C18 Internal Olefin Drilling Fluid Formulation 8 Appendix 8 to Subpart A of Part 435 Protection of Environment ENVIRONMENTAL...—Reference C16-C18 Internal Olefin Drilling Fluid Formulation The reference C16-C18 internal olefin...

  9. Bilingualism in International Baccalaureate Programmes, with Particular Reference to International Schools

    ERIC Educational Resources Information Center

    Carder, Maurice

    2006-01-01

    Students successfully completing an International Baccalaureate (IB) Diploma course of study may, under certain conditions, be awarded a Bilingual Diploma. Since many students in international schools may be expected to be bilingual, and bilingualism, properly nurtured, has been shown to have metalinguistic and cognitive advantages, it would be…

  10. Signatures of strong geomagnetic storms in the equatorial latitude

    NASA Astrophysics Data System (ADS)

    Olawepo, A. O.; Adeniyi, J. O.

    2014-04-01

    Ionosonde data from two equatorial stations in the African sector have been used to study the signatures of four strong geomagnetic storms on the height - electron density profiles of the equatorial ionosphere with the objective of investigating the effects and extent of the effects on the three layers of the equatorial ionosphere. The results showed that strong geomagnetic storms produced effects of varying degrees on the three layers of the ionosphere. Effect of strong geomagnetic storms on the lower layers of the equatorial ionosphere can be significant when compared with effect at the F2-layer. Fluctuations in the height of ionization within the E-layer were as much as 0% to +20.7% compared to -12.5% to +8.3% for the F2-layer. The 2007 version of the International Reference Ionosphere, IRI-07 storm-time model reproduced responses at the E-layer but overestimated the observed storm profiles for the F1- and F2-layers.

  11. Observations in the South Atlantic Geomagnetic Anomaly with Intercosmos-Bulgaria-1300 during a geomagnetic storm

    SciTech Connect

    Gogoshev, M.M.; Gogosheva, TS.N.; Kostadinov, I.N.; Markova, T.I.; Kisovski, S.

    1985-01-01

    The region of South Atlantic Geomagnetic Anomaly was investigated by the Intercosmos-Bulgaria-1300 satellite, launched on August 7, 1981. On the basis of data obtained from 15 orbits during increased geomagnetic activity in August 1981, a map of the Anomaly was elaborated. Two centers of activity were identified. By means of the EMO-5 electrophotometer on board the Intercosmos-Bulgaria-1300 satellite, the atmosphere glow in lines 5577 A, 6300 A and 4278 A was studied. 11 references.

  12. The Vector Matching Method in Geomagnetic Aiding Navigation

    PubMed Central

    Song, Zhongguo; Zhang, Jinsheng; Zhu, Wenqi; Xi, Xiaoli

    2016-01-01

    In this paper, a geomagnetic matching navigation method that utilizes the geomagnetic vector is developed, which can greatly improve the matching probability and positioning precision, even when the geomagnetic entropy information in the matching region is small or the geomagnetic contour line’s variety is obscure. The vector iterative closest contour point (VICCP) algorithm that is proposed here has better adaptability with the positioning error characteristics of the inertial navigation system (INS), where the rigid transformation in ordinary ICCP is replaced with affine transformation. In a subsequent step, a geomagnetic vector information fusion algorithm based on Bayesian statistical analysis is introduced into VICCP to improve matching performance further. Simulations based on the actual geomagnetic reference map have been performed for the validation of the proposed algorithm. PMID:27447645

  13. The Vector Matching Method in Geomagnetic Aiding Navigation.

    PubMed

    Song, Zhongguo; Zhang, Jinsheng; Zhu, Wenqi; Xi, Xiaoli

    2016-01-01

    In this paper, a geomagnetic matching navigation method that utilizes the geomagnetic vector is developed, which can greatly improve the matching probability and positioning precision, even when the geomagnetic entropy information in the matching region is small or the geomagnetic contour line's variety is obscure. The vector iterative closest contour point (VICCP) algorithm that is proposed here has better adaptability with the positioning error characteristics of the inertial navigation system (INS), where the rigid transformation in ordinary ICCP is replaced with affine transformation. In a subsequent step, a geomagnetic vector information fusion algorithm based on Bayesian statistical analysis is introduced into VICCP to improve matching performance further. Simulations based on the actual geomagnetic reference map have been performed for the validation of the proposed algorithm. PMID:27447645

  14. On the geomagnetic jerk of 1969

    NASA Astrophysics Data System (ADS)

    McLeod, M. G.

    1985-05-01

    Courtillot et al. (1978) have first reported a sudden change in the slope of the first time derivatives of the geomagnetic field components which occurred around 1970. It was found that the change took place in a large part of the northern hemisphere. Malin and Hodder (1982) reported on studies which were conducted to determine whether this 1970 step change in the second time derivative of the geomagnetic field components, which they termed a geomagnetic 'jerk', was of internal or external origin. It was concluded that internal sources can give rise to changes in secular variation on time scales as short as one or two years and that these were the major factor in the geomagnetic jerk which occurred around 1970. The present paper provides new supporting evidence for the existence of a worldwide geomagnetic jerk, its (average) time of occurrence, and its internal nature. New estimates are given of the spherical harmonic coefficients of the jerk and of the pre-1969 and post-1969 secular acceleration.

  15. On the geomagnetic jerk of 1969

    NASA Technical Reports Server (NTRS)

    Mcleod, M. G.

    1985-01-01

    Courtillot et al. (1978) have first reported a sudden change in the slope of the first time derivatives of the geomagnetic field components which occurred around 1970. It was found that the change took place in a large part of the northern hemisphere. Malin and Hodder (1982) reported on studies which were conducted to determine whether this 1970 step change in the second time derivative of the geomagnetic field components, which they termed a geomagnetic 'jerk', was of internal or external origin. It was concluded that internal sources can give rise to changes in secular variation on time scales as short as one or two years and that these were the major factor in the geomagnetic jerk which occurred around 1970. The present paper provides new supporting evidence for the existence of a worldwide geomagnetic jerk, its (average) time of occurrence, and its internal nature. New estimates are given of the spherical harmonic coefficients of the jerk and of the pre-1969 and post-1969 secular acceleration.

  16. The Second Realization of the International Celestial Reference Frame by Very Long Baseline Interferometry

    NASA Astrophysics Data System (ADS)

    Fey, A. L.; Gordon, D.; Jacobs, C. S.; Ma, C.; Gaume, R. A.; Arias, E. F.; Bianco, G.; Boboltz, D. A.; Böckmann, S.; Bolotin, S.; Charlot, P.; Collioud, A.; Engelhardt, G.; Gipson, J.; Gontier, A.-M.; Heinkelmann, R.; Kurdubov, S.; Lambert, S.; Lytvyn, S.; MacMillan, D. S.; Malkin, Z.; Nothnagel, A.; Ojha, R.; Skurikhina, E.; Sokolova, J.; Souchay, J.; Sovers, O. J.; Tesmer, V.; Titov, O.; Wang, G.; Zharov, V.

    2015-08-01

    We present the second realization of the International Celestial Reference Frame (ICRF2) at radio wavelengths using nearly 30 years of Very Long Baseline Interferometry observations. ICRF2 contains precise positions of 3414 compact radio astronomical objects and has a positional noise floor of ∼40 μas and a directional stability of the frame axes of ∼10 μas. A set of 295 new “defining” sources was selected on the basis of positional stability and the lack of extensive intrinsic source structure. The positional stability of these 295 defining sources and their more uniform sky distribution eliminates the two greatest weaknesses of the first realization of the International Celestial Reference Frame (ICRF1). Alignment of ICRF2 with the International Celestial Reference System was made using 138 positionally stable sources common to both ICRF2 and ICRF1. The resulting ICRF2 was adopted by the International Astronomical Union as the new fundamental celestial reference frame, replacing ICRF1 as of 2010 January 1.

  17. Assessment of international reference materials for isotope-ratio analysis (IUPAC Technical Report)

    USGS Publications Warehouse

    Brand, Willi A.; Coplen, Tyler B.; Vogl, Jochen; Rosner, Martin; Prohaska, Thomas

    2014-01-01

    Since the early 1950s, the number of international measurement standards for anchoring stable isotope delta scales has mushroomed from 3 to more than 30, expanding to more than 25 chemical elements. With the development of new instrumentation, along with new and improved measurement procedures for studying naturally occurring isotopic abundance variations in natural and technical samples, the number of internationally distributed, secondary isotopic reference materials with a specified delta value has blossomed in the last six decades to more than 150 materials. More than half of these isotopic reference materials were produced for isotope-delta measurements of seven elements: H, Li, B, C, N, O, and S. The number of isotopic reference materials for other, heavier elements has grown considerably over the last decade. Nevertheless, even primary international measurement standards for isotope-delta measurements are still needed for some elements, including Mg, Fe, Te, Sb, Mo, and Ge. It is recommended that authors publish the delta values of internationally distributed, secondary isotopic reference materials that were used for anchoring their measurement results to the respective primary stable isotope scale.

  18. The Reciprocal Internal/External Frame of Reference Model Using Grades and Test Scores

    ERIC Educational Resources Information Center

    Möller, Jens; Zimmermann, Friederike; Köller, Olaf

    2014-01-01

    Background: The reciprocal I/E model (RI/EM) combines the internal/external frame of reference model (I/EM) with the reciprocal effects model (REM). The RI/EM extends the I/EM longitudinally and the REM across domains. The model predicts that, within domains, mathematics and verbal achievement (VACH) and academic self-concept have positive effects…

  19. 40 CFR Appendix 8 to Subpart A of... - Reference C16-C18 Internal Olefin Drilling Fluid Formulation

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Reference C16-C18 Internal Olefin Drilling Fluid Formulation 8 Appendix 8 to Subpart A of Part 435 Protection of Environment ENVIRONMENTAL... Internal Olefin Drilling Fluid Formulation The reference C16-C18 internal olefin drilling fluid used...

  20. Non-singular spherical harmonic expressions of geomagnetic vector and gradient tensor fields in the local north-oriented reference frame

    NASA Astrophysics Data System (ADS)

    Du, J.; Chen, C.; Lesur, V.; Wang, L.

    2014-12-01

    General expressions of magnetic vector (MV) and magnetic gradient tensor (MGT) in terms of the first- and second-order derivatives of spherical harmonics at different degrees and orders, are relatively complicated and singular at the poles. In this paper, we derived alternative non-singular expressions for the MV, the MGT and also the higher-order partial derivatives of the magnetic field in local north-oriented reference frame. Using our newly derived formulae, the magnetic potential, vector and gradient tensor fields at an altitude of 300 km are calculated based on a global lithospheric magnetic field model GRIMM_L120 (version 0.0) and the main magnetic field model of IGRF11. The corresponding results at the poles are discussed and the validity of the derived formulas is verified using the Laplace equation of the potential field.

  1. Improving the efficiency of quantitative (1)H NMR: an innovative external standard-internal reference approach.

    PubMed

    Huang, Yande; Su, Bao-Ning; Ye, Qingmei; Palaniswamy, Venkatapuram A; Bolgar, Mark S; Raglione, Thomas V

    2014-01-01

    The classical internal standard quantitative NMR (qNMR) method determines the purity of an analyte by the determination of a solution containing the analyte and a standard. Therefore, the standard must meet the requirements of chemical compatibility and lack of resonance interference with the analyte as well as a known purity. The identification of such a standard can be time consuming and must be repeated for each analyte. In contrast, the external standard qNMR method utilizes a standard with a known purity to calibrate the NMR instrument. The external standard and the analyte are measured separately, thereby eliminating the matter of chemical compatibility and resonance interference between the standard and the analyte. However, the instrumental factors, including the quality of NMR tubes, must be kept the same. Any deviations will compromise the accuracy of the results. An innovative qNMR method reported herein utilizes an internal reference substance along with an external standard to assume the role of the standard used in the traditional internal standard qNMR method. In this new method, the internal reference substance must only be chemically compatible and be free of resonance-interference with the analyte or external standard whereas the external standard must only be of a known purity. The exact purity or concentration of the internal reference substance is not required as long as the same quantity is added to the external standard and the analyte. The new method reduces the burden of searching for an appropriate standard for each analyte significantly. Therefore the efficiency of the qNMR purity assay increases while the precision of the internal standard method is retained. PMID:24013124

  2. Morphology of the southern African geomagnetic field derived from observatory and repeat station survey observations: 2005-2014

    NASA Astrophysics Data System (ADS)

    Kotzé, P. B.; Korte, M.

    2016-02-01

    Geomagnetic field data from four observatories and annual field surveys between 2005 and 2015 provide a detailed description of Earth's magnetic field changes over South Africa, Namibia and Botswana on time scales of less than 1 year. The southern African area is characterized by rapid changes in the secular variation pattern and lies in close proximity to the South Atlantic Anomaly (SAA) where the geomagnetic field intensity is almost 30 % weaker than in other regions at similar latitudes around the globe. Several geomagnetic secular acceleration (SA) pulses (geomagnetic jerks) around 2007, 2010 and 2012 could be identified over the last decade in southern Africa. We present a new regional field model for declination and horizontal and vertical intensity over southern Africa (Southern African REGional (SAREG)) which is based on field survey and observatory data and covering the time interval from 2005 to 2014, i.e. including the period between 2010 and 2013 when no low Earth-orbiting vector field satellite data are available. A comparative evaluation between SAREG and global field models like CHAOS-5, the CHAMP, Orsted and SAC-C model of the Earth's magnetic field and International Geomagnetic Reference Field (IGRF-12) reveals that a simple regional field model based on a relatively dense ground network is able to provide a realistic representation of the geomagnetic field in this area. We particularly note that a global field model like CHAOS-5 does not always indicate similar short-period patterns in the field components as revealed by observatory data, while representing the general secular variation reasonably well during the time interval without near-Earth satellite vector field data. This investigation further shows the inhomogeneous occurrence and distribution of secular variation impulses in the different geomagnetic field components and at different locations in southern African.

  3. Global geomagnetic field mapping - from secular variation to geomagnetic excursions

    NASA Astrophysics Data System (ADS)

    Panovska, Sanja; Constable, Catherine

    2015-04-01

    The main source of the geomagnetic field is a self-sustaining dynamo produced by fluid motions in Earth's liquid outer core. We study the spatial and temporal changes in the internal magnetic field by mapping the time-varying geomagnetic field over the past 100 thousand years. This is accomplished using a new global data set of paleomagnetic records drawn from high accumulation rate sediments and from volcanic rocks spanning the past 100 thousand years (Late Pleistocene). Sediment data comprises 105 declination, 117 inclination and 150 relative paleointensity (RPI) records, mainly concentrated in northern mid-latitudes, although some are available in the southern hemisphere. Northern Atlantic and Western Pacific are regions with high concentrations of data. The number of available volcanic/archeomagnetic data is comparitively small on the global scale, especially in the Southern hemisphere. Temporal distributions show that the number of data increases toward more recent times with a good coverage for the past 50 ka. Laschamp excursion (41 ka BP) is well represented for both directional and intensity data. The significant increase in data compared to previous compilations results in an improvement over current geomagnetic field models covering these timescales. Robust aspects of individual sediment records are successfully captured by smoothing spline modeling allowing an estimate of random uncertainties present in the records. This reveals a wide range of fidelities across the sediment magnetic records. Median uncertainties are: 17° for declination (range, 1° to 113°), 6° for inclination (1° to 50°) and 0.4 for standardized relative paleointensity (0.02 to 1.4). The median temporal resolution of the records defined by the smoothing time is 400 years (range, 50 years to about 14 kyr). Using these data, a global, time-varying, geomagnetic field model is constructed covering the past 100 thousand years. The modeling directly uses relative forms of sediment

  4. Demonstration of glass transition temperature shift in thin supported polystyrene films by internal reference method

    NASA Astrophysics Data System (ADS)

    Efremov, Mikhail Yu.; Thode, Christopher; Nealey, Paul F.

    2013-02-01

    An internal reference method is used for the first time to clearly demonstrate the glass transition temperature (Tg) depression effect in 5 nm thick polystyrene films spin-cast on silicon wafers. Initially flat films exhibit depressed Tg at approximately 85 °C. Temperature-induced dewetting on hexamethyldisilazane-treated silicon substrates leads to formation of discontinuous films with average effective thickness of 15-30 nm. Dewetted films demonstrate Tg close to the bulk value (≈ 100 °C) and are used as internal references. Data both for continuous and discontinuous films are obtained in the same experimental run for the same sample, which allows direct comparison between datasets. Phase-modulated ellipsometry in vacuum is used to monitor glass transition. Both traditional linear temperature scan method and a novel temperature modulated technique have been employed in the measurements.

  5. Data Assimilation as a Tool for Developing a Mars International Reference Atmosphere

    NASA Technical Reports Server (NTRS)

    Houben, Howard

    2005-01-01

    A new paradigm for a Mars International Reference Atmosphere is proposed. In general, as is certainly now the case for Mars, there are sufficient observational data to specify what the full atmospheric state was under a variety of circumstances (season, dustiness, etc.). There are also general circulation models capable of deter- mining the evolution of these states. If these capabilities are combined-using data assimilation techniques-the resulting analyzed states can be probed to answer a wide variety of questions, whether posed by scientists, mission planners, or others. This system would fulfill all the purposes of an international reference atmosphere and would make the scientific results of exploration missions readily available to the community. Preliminary work on a website that would incorporate this functionality has begun.

  6. Forward mapping of solar energetic proton distributions through the geomagnetic field

    NASA Astrophysics Data System (ADS)

    Kouznetsov, A.; Knudsen, D. J.

    2013-08-01

    During solar proton events, large ejections of energetic protons spread throughout the interplanetary medium, penetrate the geomagnetic field, and are deposited in the upper polar atmosphere where they play important roles in its physical and chemical processes. We develop a model of direct proton propagation through a static geomagnetic field based on a generalized leapfrog method and validate it through comparison with Störmer theory. We then apply the algorithm to two ideal cases representing the late and early phases of a solar particle event, for proton energies of 10, 100, and 1000 MeV. The late-phase case is represented by an isotropic infinite bath of protons surrounding the magnetosphere; in this case, most protons reaching the polar cap originate within ±20° of the magnetic equatorial plane, with pronounced peaks near ±20°. The early-phase case is represented by broad, monodirectional proton beams; these sources are highly focused by the geomagnetic field, with all particles mapping to small regions in the polar cap only a few hundred kilometers across, and with low-energy particles being focused more than higher-energy ones. Pure dipole and International Geomagnetic Reference Field-11 magnetic field models lead to very similar fluence patterns in the polar cap, though the latter are somewhat less focused.

  7. The reference ear modeling method for internally feedback controlled digital hearing aid chip.

    PubMed

    Kim, Sunyoung; Lee, Seung Jin; Cho, Namjun; Song, Seong-Jun; Yoo, Hoi-Jun

    2007-01-01

    A reference ear modeling method for the real-time feedback controlled digital hearing aid chip is proposed and implemented. In order to reduce the modeling complexity and enhance the programmability, new ear modeling method using the acoustic filter theory is adopted to the digital hearing aid. To achieve the fully internal gain fitting and verification system, the responses from the damaged ear and the reference ear model are compared and the new gain parameters are processed for the multi-channel DSP. The digital hearing aid chip with reference ear model is fabricated in 0.18 microm CMOS technology, has a core area of 3.1 mm x 1.2 mm and dissipates less than 120 muA. PMID:18003331

  8. Ratiometric electrochemical immunoassay based on internal reference value for reproducible and sensitive detection of tumor marker.

    PubMed

    Cai, Xiaohui; Weng, Shaohuang; Guo, Rubin; Lin, Liqing; Chen, Wei; Zheng, Zongfu; Huang, Zhengjun; Lin, Xinhua

    2016-07-15

    A ratiometric assay in an electrochemical immunosensor for tumor marker, herein carcinoembryonic antigen (CEA) was chosen as a model analyte, was developed to improve simplicity and accuracy. The immunosensor was fabricated via the simple expedient way of using Polythionine-gold (PTh-Au) as electrode modified material to be an internal reference signal and K3[Fe(CN)6] in electrolyte as an indicator signal. When the CEA was fixed on the modified electrode via immunoreaction, only the indicator signal sensitively altered; by contrast, the internal reference signal of PTh-Au remained constant at a suitable pH of the electrolyte. The ratio between the alterations of the indicator signal of K3[Fe(CN)6] and the constant internal reference signal can be used to monitor the concentration of CEA reliably, reproducibly, and sensitively. The prepared ratiometric electrochemical immunosensor could detect CEA with good specificity within a wide linear range from 0.005ng/ml to 40ng/ml with a detection limit of 2.2pg/ml. Additionally, experimental results confirm that our proposed method is practical. Thus, this method can expand to recognize and test other protein markers. PMID:26945184

  9. Reference Intervals in Healthy Adult Ugandan Blood Donors and Their Impact on Conducting International Vaccine Trials

    PubMed Central

    Eller, Leigh Anne; Eller, Michael A.; Ouma, Benson; Kataaha, Peter; Kyabaggu, Denis; Tumusiime, Richard; Wandege, Joseph; Sanya, Ronald; Sateren, Warren B.; Wabwire-Mangen, Fred; Kibuuka, Hannah; Robb, Merlin L.; Michael, Nelson L.; de Souza, Mark S.

    2008-01-01

    Background Clinical trials are increasingly being conducted internationally. In order to ensure enrollment of healthy participants and proper safety evaluation of vaccine candidates, established reference intervals for clinical tests are required in the target population. Methodology/Principal Findings We report a reference range study conducted in Ugandan adult blood bank donors establishing reference intervals for hematology and clinical chemistry parameters. Several differences were observed when compared to previously established values from the United States, most notably in neutrophils and eosinophils. Conclusions/Significance In a recently conducted vaccine trial in Uganda, 31 percent (n = 69) of volunteers screened (n = 223) were excluded due to hematologic abnormalities. If local reference ranges had been employed, 83% of those screened out due to these abnormalities could have been included in the study, drastically reducing workload and cost associated with the screening process. In addition, toxicity tables used in vaccine and drug trial safety evaluations may need adjustment as some clinical reference ranges determined in this study overlap with grade 1 and grade 2 adverse events. PMID:19079547

  10. A coupling between geometry of the main geomagnetic field tectonic margins and seismicity

    NASA Astrophysics Data System (ADS)

    Khachikyan, Galina

    2013-04-01

    Integrated studies involving geomagnetism, geodynamics, and seismology are essential for advances in understanding the Earth dynamics. This work presents recent results based of the International Geomagnetic Reference Field (IGRF-10) model, Digital Tectonic Activity Map (DTAM-1), and the global seismological catalogue (173477 events for 1973-2010 with ?≥4.5). It will be shown that: 1. The geometry of the main geomagnetic field controls a spatial distribution of seismicity around the globe. This becomes apparent when geomagnetic field components are analyzed using the geocentric solar magnetospheric (GSM) coordinate system. Earthquakes prefer occur in the regions where geomagnetic Z_GSM component reaches large positive value, that takes place at low and middle latitudes. In the areas of strongest seismicity, that takes place at low and mid latitudes in the eastern hemisphere, the Z_GSM values are largest compared to all other regions of the planet. The possible maximal magnitude of earthquake (Mmax) has a linear dependence on the logarithm of absolute Z_GSM value in the epicenter in the moment of earthquake occurrence. 2. There is a geomagnetic conjugacy between certain tectonic structures. In particular, the middle ocean ridges located in the southern hemisphere along the boundary of the Antarctic tectonic plate are magnetically conjugate with the areas of junction of continental orogens and platforms in the northern hemisphere. Close magnetic conjugacy exists between southern boundary of the Nazca tectonic plate and northern boundaries of the Cocos and Caribbean plates. 3. Variations in the total strength of the main geomagnetic field could be associated, to some extent, with the earthquake occurrence. In particular, the IGRF-10 model shows that in the area of the major 2004 Sumatra earthquake (epicenter 3.3N; 95.98E), the strength of the main geomagnetic field steadily increased from ~ 41338 nT in 1980 to ~ 41855 nT in 2004 with a mean change per year of about

  11. Geomagnetic disturbances imprints in ground and satellite altitude observatories

    NASA Astrophysics Data System (ADS)

    Yahiat, Yasmina; Lamara, Souad; Zaourar, Naima; Hamoudi, Mohamed

    2016-04-01

    The temporal evolution of the geomagnetic field and its variations have been repeatedly studied from both ground observatories and near-earth orbiting platforms. With the advent of the space ageand the launches of geomagnetic low altitude orbits satellites, a global coverage has been achieved. Since Magsat mission, more satellites were put into orbit and some of them are still collecting data enhancing the spatial and temporal descriptions of the field. Our study uses new data gathered by the latest SWARM satellite mission launched on November, 22nd 2013. It consists of a constellation of three identical satellites carrying on board high resolution and accuracy scientific equipment. Data from this constellation will allow better understanding the multiscale behavior of the geomagnetic field. Our goal is to analyze and interpret the geomagnetic data collected by this Swarm mission, for a given period and try to separate the external disturbances from internal contributions. We consider in the study the variation of the horizontal component H, for different virtual geomagnetic observatories at the satellite altitude. The analysis of data by Swarm orbital segments shows clearly the external disturbances of the magnetic field like that occurring on 27th of August 2014. This perturbation is shown on geomagnetic indexes and is related to a coronal mass ejection (CME). These results from virtual observatories are confirmed, by the equivalent analysis using ground observatories data for the same geographic positions and same epochs. Key words: Geomagnetic field, external field, geomagnetic index, SWARM mission, virtual observatories.

  12. Simulation Of Fluctuating Geomagnetic Index

    NASA Technical Reports Server (NTRS)

    Vedder, John; Tabor, Jill

    1993-01-01

    Mathematical model produces synthetic geomagnetic-index (ap) data including short-term fluctuations like those of real ap data. Measures geomagnetic activity computed from measurements of fluctuations in geomagnetic field taken at 12 high-latitude stations every 3 hours. Used in studies of interactions between solar wind and Earth, especially in studies of effect of geomagnetic field upon heating of thermosphere by impacts of energetic charged solar-wind particles.

  13. VizieR Online Data Catalog: International Celestial Reference Frame 2, ICRF2 (Ma+, 2009)

    NASA Astrophysics Data System (ADS)

    Ma, C.; Arias, F. E.; Bianco, G.; Boboltz, D. A.; Bolotin, S. L.; Charlot, P.; Engelhardt, G.; Fey, A. L.; Gaume, R. A.; Gontier, A.-M.; Heinkelmann, R.; Jacobs, C. S.; Kurdubov, S.; Lambert, S. B.; Malkin, Z. M.; Nothnagel, A.; Petrov, L.; Skurikhina, E.; Sokolova, J. R.; Souchay, J.; Sovers, O. J.; Tesmer, V.; Titov, O. A.; Wang, G.; Zharov, V. E.; Barache, C.; Bockmann, S.; Collioud, A.; Gipson, J. M.; Gordon, D.; Lytvyn, S. O.; MacMillan, D. S.; Ojha, R.; Fey, A. L.; Gordon, D.; Jacobs, C. S.

    2013-06-01

    This Technical Note describes the generation by an international team of the second realization of the International Celestial Reference Frame (ICRF2) at radio wavelengths using nearly 30 years of Very Long Baseline Interferometry (VLBI) observations. ICRF2 contains precise positions of 3414 compact radio astronomical sources, more than five times the number as in the first ICRF, hereafter ICRF1. Further, the ICRF2 is found to have a noise floor of only 40μas, some 5-6 times better than ICRF1, and an axis stability of 10μas, nearly twice as stable as ICRF1. Alignment of ICRF2 with the International Celestial Reference System (ICRS) was made using 138 stable sources common to both ICRF2 and ICRF1-Ext2. Future maintenance of ICRF2 will be made using a set of 295 new "defining" sources selected on the basis of positional stability and the lack of extensive intrinsic source structure. The stability of these 295 defining sources, and their more uniform sky distribution eliminates the two largest weaknesses of ICRF1. (2 data files).

  14. Research Activities for the DORIS Contribution to the Next International Terrestrial Reference Frame

    NASA Technical Reports Server (NTRS)

    Soudarin, L.; Moreaux, G.; Lemoine, F.; Willis, P.; Stepanek, P.; Otten, M.; Govind, R.; Kuzin, S.; Ferrage, P.

    2012-01-01

    For the preparation of ITRF2008, the IDS processed data from 1993 to 2008, including data from TOPEX/Poseidon, the SPOT satellites and Envisat in the weekly solutions. Since the development of ITRF2008, the IDS has been engaged in a number of efforts to try and improve the reference frame solutions. These efforts include (i) assessing the contribution of the new DORIS satellites, Jason-2 and Cryosat2 (2008-2011), (ii) individually analyzing the DORIS satellite contributions to geocenter and scale, and (iii) improving orbit dynamics (atmospheric loading effects, satellite surface force modeling. . . ). We report on the preliminary results from these research activities, review the status of the IDS combination which is now routinely generated from the contributions of the IDS analysis centers, and discuss the prospects for continued improvement in the DORIS contribution to the next international reference frame.

  15. OPTICAL SPECTRA OF CANDIDATE SOUTHERN HEMISPHERE INTERNATIONAL CELESTIAL REFERENCE FRAME (ICRF) RADIO SOURCES

    SciTech Connect

    Titov, O.; Jauncey, D. L.; Johnston, H. M.; Hunstead, R. W.; Christensen, L.

    2011-11-15

    We present the results of spectroscopic observations of the optical counterparts of 47 southern radio sources from the candidate International Celestial Reference Catalogue as part of a very long baseline interferometry (VLBI) program to strengthen the celestial reference frame, especially in the south. We made the observations with the 3.58 m European Southern Observatory New Technology Telescope. We obtained redshifts for 30 quasars and one radio galaxy, with a further seven objects being probable BL Lac objects with featureless spectra. Of the remainder, four were clear misidentifications with Galactic stars and five had low signal-to-noise spectra and could not be classified. These results, in combination with new VLBI data of the radio sources with redshifts more than 2, add significantly to the existing data needed to refine the distribution of source proper motions over the celestial sphere.

  16. OPTICAL SPECTRA OF CANDIDATE INTERNATIONAL CELESTIAL REFERENCE FRAME (ICRF) FLAT-SPECTRUM RADIO SOURCES

    SciTech Connect

    Titov, O.; Stanford, Laura M.; Johnston, Helen M.; Hunstead, Richard W.; Pursimo, T.; Jauncey, David L.; Maslennikov, K.

    2013-07-01

    Continuing our program of spectroscopic observations of International Celestial Reference Frame (ICRF) sources, we present redshifts for 120 quasars and radio galaxies. Data were obtained with five telescopes: the 3.58 m European Southern Observatory New Technology Telescope, the two 8.2 m Gemini telescopes, the 2.5 m Nordic Optical Telescope (NOT), and the 6.0 m Big Azimuthal Telescope of the Special Astrophysical Observatory in Russia. The targets were selected from the International VLBI Service for Geodesy and Astrometry candidate International Celestial Reference Catalog which forms part of an observational very long baseline interferometry (VLBI) program to strengthen the celestial reference frame. We obtained spectra of the potential optical counterparts of more than 150 compact flat-spectrum radio sources, and measured redshifts of 120 emission-line objects, together with 19 BL Lac objects. These identifications add significantly to the precise radio-optical frame tie to be undertaken by Gaia, due to be launched in 2013, and to the existing data available for analyzing source proper motions over the celestial sphere. We show that the distribution of redshifts for ICRF sources is consistent with the much larger sample drawn from Faint Images of the Radio Sky at Twenty cm (FIRST) and Sloan Digital Sky Survey, implying that the ultra-compact VLBI sources are not distinguished from the overall radio-loud quasar population. In addition, we obtained NOT spectra for five radio sources from the FIRST and NRAO VLA Sky Survey catalogs, selected on the basis of their red colors, which yielded three quasars with z > 4.

  17. Representation of the Auroral and Polar Ionosphere in the International Reference Ionosphere (IRI)

    NASA Technical Reports Server (NTRS)

    Bilitza, Dieter; Reinisch, Bodo

    2013-01-01

    This issue of Advances in Space Research presents a selection of papers that document the progress in developing and improving the International Reference Ionosphere (IRI), a widely used standard for the parameters that describe the Earths ionosphere. The core set of papers was presented during the 2010 General Assembly of the Committee on Space Research in Bremen, Germany in a session that focused on the representation of the auroral and polar ionosphere in the IRI model. In addition, papers were solicited and submitted from the scientific community in a general call for appropriate papers.

  18. A study to establish international diagnostic reference levels for paediatric computed tomography.

    PubMed

    Vassileva, J; Rehani, M; Kostova-Lefterova, D; Al-Naemi, H M; Al Suwaidi, J S; Arandjic, D; Bashier, E H O; Kodlulovich Renha, S; El-Nachef, L; Aguilar, J G; Gershan, V; Gershkevitsh, E; Gruppetta, E; Hustuc, A; Jauhari, A; Kharita, Mohammad Hassan; Khelassi-Toutaoui, N; Khosravi, H R; Khoury, H; Kralik, I; Mahere, S; Mazuoliene, J; Mora, P; Muhogora, W; Muthuvelu, P; Nikodemova, D; Novak, L; Pallewatte, A; Pekarovič, D; Shaaban, M; Shelly, E; Stepanyan, K; Thelsy, N; Visrutaratna, P; Zaman, A

    2015-07-01

    The article reports results from the largest international dose survey in paediatric computed tomography (CT) in 32 countries and proposes international diagnostic reference levels (DRLs) in terms of computed tomography dose index (CTDI vol) and dose length product (DLP). It also assesses whether mean or median values of individual facilities should be used. A total of 6115 individual patient data were recorded among four age groups: <1 y, >1-5 y, >5-10 y and >10-15 y. CTDIw, CTDI vol and DLP from the CT console were recorded in dedicated forms together with patient data and technical parameters. Statistical analysis was performed, and international DRLs were established at rounded 75th percentile values of distribution of median values from all CT facilities. The study presents evidence in favour of using median rather than mean of patient dose indices as the representative of typical local dose in a facility, and for establishing DRLs as third quartile of median values. International DRLs were established for paediatric CT examinations for routine head, chest and abdomen in the four age groups. DRLs for CTDI vol are similar to the reference values from other published reports, with some differences for chest and abdomen CT. Higher variations were observed between DLP values, based on a survey of whole multi-phase exams. It may be noted that other studies in literature were based on single phase only. DRLs reported in this article can be used in countries without sufficient medical physics support to identify non-optimised practice. Recommendations to improve the accuracy and importance of future surveys are provided. PMID:25836685

  19. Middle Atmosphere Program. Handbook for MAP. Volume 31: Reference models of trace species for the COSPAR international reference atmosphere

    NASA Technical Reports Server (NTRS)

    Keating, G. M. (Editor)

    1989-01-01

    A set of preliminary reference atmosphere models of significant trace species which play important roles in controlling the chemistry, radiation budget, and circulation patterns of the atmosphere were produced. These models of trace species distributions are considered to be reference models rather than standard models; thus, it was not crucial that they be correct in an absolute sense. These reference models can serve as a means of comparison between individual observations, as a first guess in inversion algorithms, and as an approximate representation of observations for comparison to theoretical calculations.

  20. Modeling of geomagnetic field secular variations observed in the Balkan area for purposes of regional topographic mapping

    NASA Astrophysics Data System (ADS)

    Metodiev, Metodi; Trifonova, Petya; Buchvarov, Ivan

    2014-05-01

    The most significant of the Earth's magnetic field elements is the geomagnetic declination, which is widely used in geodesy, cartography and their associated navigational systems. The geomagnetic declination is incorporated in the naval navigation maps and is used in the navigation process. It is also a very important factor for aviation where declination data have major importance for every airport (civil or military). As the geomagnetic field changes with time but maps of the geomagnetic declination are not published annually and are reduced to an epoch in the past, it is necessary to define two additional parameters in the maps, needed to determine the value of the geomagnetic declination for a particular moment in the future: 1) estimated value of the annual declination variation and 2) a table with the average diurnal variation of the declination for a given month and hour. The goal of our research is to analyze the annual mean values of geomagnetic declination on the territory of the Balkan Peninsula for obtaining of a best fitting model of that parameter which can be used for prediction of the declination value for the next 10 years. The same study was performed in 1990 for the purposes of Bulgarian declination map's preparation. As a result, a linear model of the declination annual variation was obtained for the neighboring observatories and repeat stations data, and a map of the obtained values for the Bulgarian territory was drawn. We use the latest version of the GFZ Reference Internal Magnetic Model (GRIMM-3.0) to compare the magnetic field evolution predicted by that model between 2001 and 2010 to the data collected in five independent geomagnetic observatories in the Balkan region (PAG, SUA, PEG, IZN, GCK) over the same time interval. We conclude that the geomagnetic core field secular variation in this area is well described by the global model. The observed small-scale differences might indicate induced lithospheric anomalies but it is still an open

  1. The International Reference Ionosphere: A review of current activities and plans for the future

    NASA Astrophysics Data System (ADS)

    Bilitza, Dieter

    2014-05-01

    The International Reference Ionosphere (IRI) is at the core of many assimilative models of the global ionosphere that aspire to provide a more accurate representation of the 4-D ionosphere by combining a core ionosphere model with GNSS and other data sets. This presentation will review the status of the International Reference Ionosphere (IRI) project and model with special emphasis on activities during the last two years. We will discuss the most important IRI improvements and parameter additions that were accomplished during this time period. The scorecard includes significant improvements in the bottomside electron density and ion composition, the inclusion of solar activity variations for the topside electron temperature, and for the first time a model for auroral oval boundaries. In addition we will also review the status of several ongoing collaborative projects that promise significant future improvements for the IRI model including a better representation of the F2-peak height (hmF2), the coupling of IRI to plasmaspheric models, and the development of a real-time IRI (IRI-RT). Work also continues on the accurate IRI representation of ionosphere conditions during the recent highly unusually low and extended solar minimum. Time permitting, we will briefly discuss recent IRI-related meetings and workshops and their outcomes, and present some recent IRI usage statistics.

  2. Geomagnetism and climate V: general conclusions

    NASA Astrophysics Data System (ADS)

    Mörner, N.-A.; Nevanlinna, H.; Dergachev, V.; Shumilov, O.; Raspopov, O.; Abrahamsen, N.; Pilipenko, O.; Trubikhin, V.; Gooskova, E.

    2003-04-01

    The shielding capacity of the Earth’s geomagnetic field is a prime factor regulating the flux into the atmosphere of galactic cosmic ray (in its turn controlling the 14C and 10Be production). This shielding capacity is controlled both by the Earth’s own geomagnetic field variability and by the Solar Wind variations. The Solar Wind interaction with the magnetosphere also affects the Earth’s rate of rotation (as recorded in the correlation between LOD and Sunspot activity). This opens for three possible lines of Solar Terrestrial interaction. (1) Changes in the total irradiance (known to be very small, however, over a full sun spot cycle). (2) Changes in cosmic ray flux reaching into the Earth’s atmosphere where it has the potential of affecting airglow and cloudiness (especially the cloudiness at a height in the order of 15 km). (3) Changes in the Earth’s rate of rotation affecting the oceanic circulation redistributing ocean-stored heat and water masses. The Spörer, Maunder and Dalton sun spot minima seem all to have led to periods of rotational acceleration pulling Arctic water down the European coasts and displacing the warm Gulf Stream towards Gibraltar. The geomagnetic field as regulator of cosmic ray flux and rotational potential is likely to have played a significant role even over longer time periods. It should be noted, however, the geometry of the Earth’s geomagnetic field cannot have differed very much due to frozen plasma conditions even at excursions and reversals. If the recorded sunspot and geomagnetic cycles are extrapolated into the future they predict a new low (“Little Ice Age”) in the years 2050 2100 (i.e. a scenario very different from that presented by IPCC). Our study of the relation between geomagnetism and climate has shown that geomagnetic field changes have played an important role in modulation Earth’s climate. These changes may originate from internal planetary sources (i.e. the Earth’s own geomagnetic field) as well

  3. Introduction to Geomagnetic Fields

    NASA Astrophysics Data System (ADS)

    Hinze, William J.

    Coincidentally, as I sat down in late October 2003 to read and review the second edition of Wallace H. Campbell's text, Introduction to Geomagnetic Fields, we received warnings from the news media of a massive solar flare and its possible effect on power supply systems and satellite communications. News programs briefly explained the source of Sun-Earth interactions. If you are interested in learning more about the physics of the connection between sun spots and power supply systems and their impact on orbiting satellites, I urge you to become acquainted with Campbell's book. It presents an interesting and informative explanation of the geomagnetic field and its applications to a wide variety of topics, including oil exploration, climate change, and fraudulent claims of the utility of magnetic fields for alleviating human pain. Geomagnetism, the study of the nature and processes of the Earth's magnetic fields and its application to the investigation of the Earth, its processes, and history, is a mature science with a well-developed theoretical foundation and a vast array of observations. It is discussed in varied detail in Earth physics books and most entry-level geoscience texts. The latter treatments largely are driven by the need to discuss paleomagnetism as an essential tool in studying plate tectonics. A more thorough explanation of geomagnetism is needed by many interested scientists in related fields and by laypersons. This is the objective of Campbell's book. It is particularly germane in view of a broad range of geomagnetic topics that are at the forefront of today's science, including environmental magnetism, so-called ``jerks'' observed in the Earth's magnetic field, the perplexing magnetic field of Mars, improved satellite magnetic field observations, and the increasing availability of high-quality continental magnetic anomaly maps, to name only a few.

  4. New Observations Testing the Adopted HIPPARCOS Link to the International Celestial Reference Frame

    NASA Astrophysics Data System (ADS)

    Stone, Ronald C.

    1998-10-01

    This paper tests the Hipparcos link to the extragalactic reference frame by using new data obtained after the release of the catalog, thereby providing an external check on the accuracy of the established link process. The new data consist of 689 positions of Hipparcos stars determined in the International Celestial Reference Frame (ICRF) from CCD observations taken with the Flagstaff Astrometric Scanning Transit Telescope (FASTT). A comparison of the FASTT and Hipparcos catalog star positions observed in common finds that the axial rotations between the Hipparcos and ICRF reference frames are, respectively, (εx, εy, εz) = (-2.2+/-3.3, -2.2+/-3.3, 3.3+/-2.9) (s.e.) mas at epoch 1996.5. All of these rotations are small and insignificant with respect to their errors (εx and εy are less than 1 σ detections whereas εz is only a 1.1 σ detection). Hence, this paper finds that the Hipparcos link to the ICRF was well determined and is not seriously degrading with time.

  5. KALREF—A Kalman filter and time series approach to the International Terrestrial Reference Frame realization

    NASA Astrophysics Data System (ADS)

    Wu, Xiaoping; Abbondanza, Claudio; Altamimi, Zuheir; Chin, T. Mike; Collilieux, Xavier; Gross, Richard S.; Heflin, Michael B.; Jiang, Yan; Parker, Jay W.

    2015-05-01

    The current International Terrestrial Reference Frame is based on a piecewise linear site motion model and realized by reference epoch coordinates and velocities for a global set of stations. Although linear motions due to tectonic plates and glacial isostatic adjustment dominate geodetic signals, at today's millimeter precisions, nonlinear motions due to earthquakes, volcanic activities, ice mass losses, sea level rise, hydrological changes, and other processes become significant. Monitoring these (sometimes rapid) changes desires consistent and precise realization of the terrestrial reference frame (TRF) quasi-instantaneously. Here, we use a Kalman filter and smoother approach to combine time series from four space geodetic techniques to realize an experimental TRF through weekly time series of geocentric coordinates. In addition to secular, periodic, and stochastic components for station coordinates, the Kalman filter state variables also include daily Earth orientation parameters and transformation parameters from input data frames to the combined TRF. Local tie measurements among colocated stations are used at their known or nominal epochs of observation, with comotion constraints applied to almost all colocated stations. The filter/smoother approach unifies different geodetic time series in a single geocentric frame. Fragmented and multitechnique tracking records at colocation sites are bridged together to form longer and coherent motion time series. While the time series approach to TRF reflects the reality of a changing Earth more closely than the linear approximation model, the filter/smoother is computationally powerful and flexible to facilitate incorporation of other data types and more advanced characterization of stochastic behavior of geodetic time series.

  6. The International Terrestrial Reference Frame: current status and future challenges (Vening Meinesz Medal Lecture)

    NASA Astrophysics Data System (ADS)

    Altamimi, Zuheir

    2013-04-01

    The ability to assign accurate time-dependent coordinates to points on the Earth's surface is fundamental for many Earth observation applications. Also important is monitoring these coordinates over time in order to take into account all geophysical changes affecting the Earth's surface. Many areas of science, Earth observation, geo-referencing applications, and society at large, today depend on being able to determine positions to millimeter level precision. Point positions, to be meaningful and fully exploitable, have to be determined and expressed in a well-defined Terrestrial Reference Frame (TRF). All current global and regional reference frames rely on the availability of the International Terrestrial Reference Frame (ITRF), which is the most accurate realization of the International Terrestrial Reference System (ITRS). The positions of the thousands of geodetic stations distributed over the Earth's surface can now be determined with a precision at the level of a few millimeters and their variation over time at the level of, or better than, 1 mm/yr in a global geocentric frame. This performance is only possible as a result of the tremendous progress made in improving the hardware of the space geodetic techniques and in the high level algorithms, models, and scientific software packages developed by the analysis centers dealing with the geodetic observations accumulated over the last three decades. However, none of space geodetic techniques is able to provide all the parameters necessary to completely define a TRF (origin, scale and orientation). While satellite techniques are sensitive to the Earth center of mass (the point around which a satellite orbits; a natural TRF origin), VLBI is not (whose TRF origin is arbitrarily defined). The scale is dependent on the modeling of some physical parameters, and the absolute TRF orientation (unobservable by any technique) is arbitrary or conventionally defined through specific constraints. Therefore the value of the

  7. International Celestial Reference Frame (ICRF): mantenimiento y extensión

    NASA Astrophysics Data System (ADS)

    Ma, C.; Arias, E. F.; Eubanks, T.; Fey, A. L.; Gontier, A.-M.; Jacobs, C. S.; Sovers, O. J.; Archinal, B. A.; Charlot, P.

    A partir de enero de 1998 el sistema de referencia celeste convencional está representado por el International Celestial Reference System (ICRS) y materializado a través de las coordenadas VLBI del conjunto de radiofuentes extragalácticas que conforman el International Celestial Reference Frame (ICRF). La primera realización del ICRF, fue elaborada en 1995 por un grupo de expertos designado por la IAU, la que encomendó al International Earth Rotation Service el mantenimiento del ICRS, del ICRF y del vínculo con marcos de referencia en otras frecuencias. Una primera extensión del ICRF se realizó entre abril y junio de 1999, con el objetivo primario de proveer posiciones de radiofuentes extragalácticas observadas a partir de julio de 1995 y de mejorar las posiciones de las fuentes ``candidatas" con la inclusión de observaciones adicionales. Objetivos secundarios fueron monitorear a las radiofuentes para verificar que siguen siendo adecuadas para realizar al ICRF y mejorar las técnicas de análisis de datos. Como resultado del nuevo análisis se obtuvo una solución a partir de la cual se construyó la primera extensión del ICRF, denominada ICRF - Ext.1. Ella representa al ICRS, sus fuentes de definición se mantienen con las mismas posiciones y errores que en la primera realización del ICRF; las demás radiofuentes tienen coordenadas mejor determinadas que en ICRF; el marco de referencia se densificó con el agregado de 59 nuevas radiofuentes.

  8. Selected Bibliographies and State-of-the-Art Review for Environmental Health. Volume 2: Environmental Health References. International Health Planning Reference Series.

    ERIC Educational Resources Information Center

    Fraser, Renee White; Shani, Hadasa

    Intended as a companion piece to volume 2 in the Method Series, Environmental Health Planning (CE 024 230), this second of six volumes in the International Health Planning Reference Series is a combined literature review and annotated bibliography dealing with environmental factors in health planning for developing countries. The review identifies…

  9. A new global F2 peak electron density model for the International Reference Ionosphere (IRI)

    NASA Astrophysics Data System (ADS)

    Oyeyemi, E. O.; McKinnell, L. A.

    2008-08-01

    A new neural network (NN) based global empirical model for the F2 peak electron density (NmF2) has been developed using extended temporal and spatial geophysical relevant inputs. Measured ground based ionosonde data, from 84 global stations, spanning the period 1995 to 2005 and, for a few stations from 1976 to 1986, obtained from various resources of the World Data Centre (WDC) archives (Space Physics Interactive Data Resource SPIDR, the Digital Ionogram Database, DIDBase, and IPS Radio and Space Services) have been used for training a NN. The training data set includes all periods of quiet and disturbed magnetic activity. A comprehensive comparison for all conditions (e.g., magnetic storms, levels of solar activity, season, different regions of latitudes, etc.) between foF2 value predictions using the NN based model and International Reference Ionosphere (IRI) model (including both the International Union of Radio Science (URSI) and International Radio Consultative Committee (CCIR) coefficients) with observed values was investigated. The root-mean-square (RMS) error differences for a few selected stations are presented in this paper. The results of the foF2 NN model presented in this work successfully demonstrate that this new model can be used as a replacement option for the URSI and CCIR maps within the IRI model for the purpose of F2 peak electron density predictions.

  10. An experimental Kalman filter approach to the International Terrestrial Reference Frame realization

    NASA Astrophysics Data System (ADS)

    Wu, X.; Abbondanza, C.; Altamimi, Z.; Chin, T.; Gross, R.; Heflin, M.

    2012-04-01

    To monitor global geophysical changes with realistic uncertainties using millimeter-precision geodesy, it is essential to define, realize and maintain the International Terrestrial Reference Frame (ITRF) consistently and accurately. Precise determinations of geocentric site positions and motions, satellite orbits, geocenter motion, Earth orientation and its variations, mean sea level rise, and polar ice mass changes at various time scales all depend critically on the accuracy and stability of the ITRF. By definition, the ITRF is a secular frame based on a linear model and consisting of mean epoch positions and velocities for a global set of stations. It is needed to serve as a standard reference frame in which geophysical results can be formulated and compared. The neglected up-to centimeter-level non-linear station motion can bias the linear station velocities, which can be significantly compounded for stations with short time-span. Here, we conceptually define an experimental reference frame with its origin at the nearly instantaneous center-of-mass (CM) of the total Earth system, by specifying the frame and combining different technique data weekly (daily for Earth orientation parameters). For co-located sites, available local ties are applied only once; but site motions are usually constrained to be the same. A Kalman filter and smoother algorithm has been developed and coupled to the ITRF/CATREF software to solve for geocentric coordinate time series, as well as a model of secular, periodical and stochastic motion components. Preliminary results using linear and linear plus sinusoidal motion models without stochastic components compare very favorably with the ITRF2005 solution. With only a subset of the ITRF2005 input data time series from 1996 onward, we have obtained reference frame solutions that differ from ITRF2005 in origin by 0.6 mm and 0.3 mm/yr. Filtering strategies and time series results will also be presented.

  11. Heat balance of the ionosphere - Implications for the International Reference Ionosphere

    NASA Technical Reports Server (NTRS)

    Bilitza, D.

    1985-01-01

    Theoretical considerations can be helpful tools in modeling ionospheric parameters in regions and for times where not enough experimental data are available. This study asks whether results of heat balance calculations should be introduced to supplement the data base for the International Reference Ionosphere. The present status of the theoretical understanding is discussed and the influence of the following unresolved or neglected times are examined: (1) electron heating rate, (2) electron cooling by fine structure excitation of atomic oxygen, and (3) height-dependent Coulomb Logarithm. The ambiguity introduced by these terms leads to up to 30 percent uncertainty in the electron temperature of the lower ionosphere. The electron temperature in the upper ionosphere is largely determined by heat conduction from above and depends critically on the conditions assumed at the boundary between ionosphere and plasmasphere.

  12. Foundations of Geomagnetism

    NASA Astrophysics Data System (ADS)

    Jackson, Andy

    The study of the magnetic field of the Earth, or geomagnetism, is one of the oldest lines of scientific enquiry. Indeed, it has often been said that William Gilbert's De Magnete, published in 1600 and predating Isaac Newton's Principia by 87 years, can claim to be the first true scientific textbook; his study was essentially the first of academic rather than practical interest.What then, we may ask, has been accomplished in the nearly 400 intervening years up to the publication of Foundations of Geomagnetism? In short, a wealth of observational evidence, considerable physical understanding, and a great deal of mathematical apparatus have accrued, placing the subject on a much surer footing.The latter two categories are described in considerable detail, and with attendant rigor, in this book. The sphericity of the Earth means that a frequent theme in the book is the solution of the partial differential equations of electrodynamics in a spherical geometry.

  13. On regional geomagnetic charts

    USGS Publications Warehouse

    Alldredge, L.R.

    1987-01-01

    When regional geomagnetic charts for areas roughly the size of the US were compiled by hand, some large local anomalies were displayed in the isomagnetic lines. Since the late 1960s, when the compilation of charts using computers and mathematical models was started, most of the details available in the hand drawn regional charts have been lost. One exception to this is the Canadian magnetic declination chart for 1980. This chart was constructed using a 180 degrees spherical harmonic model. -from Author

  14. Geomagnetism. Volume I

    SciTech Connect

    Jacobs, J.A.

    1987-01-01

    The latest attempt to summarise the wealth of knowledge now available on geomagnetic phenomena has resulted in this multi-volume treatise, with contributions and reviews from many scientists. The first volume in the series contains a thorough review of all existing information on measuring the Earth's magnetic field, both on land and at sea, and includes a comparative analysis of the techniques available for this purpose.

  15. Using data of gradient magnetic surveys at altitudes of 20-40 km for the analysis of map errors and models of the geomagnetic field

    NASA Astrophysics Data System (ADS)

    Brekhov, Oleg; Tsvetkov, Yury

    2016-07-01

    Gradient geomagnetic survey at altitudes of 20-40 km from the board of stratospheric balloon have a high degree of accuracy. The data of the geomagnetic field (GMF), obtained with the help of high-precision proton magnetometer and GPS navigation receivers, are considered as a benchmark for the analysis of geomagnetic data. Gradient magnetic data is obtained by us on the balloon, allowed us to estimate the quality of the analytical models of International Geomagnetic Referent Field (IGRF) and to identify the causes of anomalous GMF map errors. Research data of magnetic anomalies map for the study area on the route length of 900 km showed that their spectrum has no harmonics with a wavelength more 130 km. This is a significant defect in a ground map. Defects of magnetic anomalies map are explained by the poor quality of the main GMF and low altitude aeromagnetic survey, as well as the presence of intense local magnetic anomalies, which does not allow reliable identifying the background of weak magnetic fields of deep sources. Using a balloon and satellite magnetic data allows creating an adequate model of the geomagnetic field up to 720.

  16. 40 CFR Appendix 8 to Subpart A of... - Reference C16-C18 Internal Olefin Drilling Fluid Formulation

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Drilling Fluid Formulation 8 Appendix 8 to Subpart A of Part 435 Protection of Environment ENVIRONMENTAL... Internal Olefin Drilling Fluid Formulation The reference C16-C18 internal olefin drilling fluid used to determine the drilling fluid sediment toxicity ratio and compliance with the BAT sediment toxicity...

  17. Spiking the Geomagnetic Field

    NASA Astrophysics Data System (ADS)

    Constable, C.; Davies, C. J.

    2015-12-01

    Geomagnetic field intensities corresponding to virtual axial dipole moments of up to 200 ZAm2, more than twice the modern value, have been inferred from archeomagnetic measurements on artifacts dated at or shortly after 1000 BC. Anomalously high values occur in the Levant and Georgia, but not in Bulgaria. The origin of this spike is believed to lie in Earth's core: however, its spatio-temporal characteristics and the geomagnetic processes responsible for such a feature remain a mystery. We show that a localized spike in the radial magnetic field at the core-mantle boundary (CMB) must necessarily contribute to the largest scale changes in Earth's surface field, namely the dipole. Even the limiting spike of a delta function at the CMB produces a minimum surface cap size of 60 degrees for a factor of two increase in paleointensity. Combined evidence from modern satellite and millennial scale field modeling suggests that the Levantine Spike is intimately associated with a strong increase in dipole moment prior to 1000 BC and likely the product of north-westward motion of concentrated near equatorial Asian flux patches like those seen in the modern field. New archeomagnetic studies are needed to confirm this interpretation. Minimum estimates of the power dissipated by the spike are comparable to independent estimates of the dissipation associated with the entire steady state geodynamo. This suggests that geomagnetic spikes are either associated with rapid changes in magnetic energy or strong Lorentz forces.

  18. On extreme geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Cid, Consuelo; Palacios, Judith; Saiz, Elena; Guerrero, Antonio; Cerrato, Yolanda

    2014-10-01

    Extreme geomagnetic storms are considered as one of the major natural hazards for technology-dependent society. Geomagnetic field disturbances can disrupt the operation of critical infrastructures relying on space-based assets, and can also result in terrestrial effects, such as the Quebec electrical disruption in 1989. Forecasting potential hazards is a matter of high priority, but considering large flares as the only criterion for early-warning systems has demonstrated to release a large amount of false alarms and misses. Moreover, the quantification of the severity of the geomagnetic disturbance at the terrestrial surface using indices as Dst cannot be considered as the best approach to give account of the damage in utilities. High temporal resolution local indices come out as a possible solution to this issue, as disturbances recorded at the terrestrial surface differ largely both in latitude and longitude. The recovery phase of extreme storms presents also some peculiar features which make it different from other less intense storms. This paper goes through all these issues related to extreme storms by analysing a few events, highlighting the March 1989 storm, related to the Quebec blackout, and the October 2003 event, when several transformers burnt out in South Africa.

  19. KALREF - A Kalman filter approach to the International Terrestrial Reference Frame realization

    NASA Astrophysics Data System (ADS)

    Wu, X.; Abbondanza, C.; Altamimi, Z.; Chin, T. M.; Collilieux, X.; Gross, R. S.; Heflin, M. B.; Hurst, K. J.; Parker, J. W.

    2012-12-01

    To monitor global geophysical changes with realistic uncertainties using millimeter-precision geodesy, it is essential to define, realize and maintain the International Terrestrial Reference Frame (ITRF) consistently and accurately. Precise determinations of geocentric site positions and motions, satellite orbits, geocenter motion, Earth orientation and its variations, mean sea level rise, and polar ice mass changes at various time scales all depend critically on the accuracy and stability of the ITRF. Currently, the ITRF is a secular frame based on a linear model and consisting of mean epoch positions and velocities for a global set of stations. With higher accuracy and density geodetic data increasingly used for near real time geophysical change determinations, a research version of Terrestrial Reference Frame (TRF) realized by station time series is needed, which combines strengths of different geodetic techniques and unifies the different technique time series in the single frame. Here, we conceptually define an experimental reference frame with its origin at the nearly instantaneous center-of-mass (CM) of the total Earth system, by specifying the frame and combining different technique data weekly (daily for Earth orientation parameters). For co-located sites, available local ties are applied only once; but site motions are usually constrained to be the same. A Kalman filter and smoother algorithm has been developed and coupled to the ITRF/CATREF software to solve for geocentric coordinate time series with a model of secular, periodical and stochastic motion components. Results using linear and linear plus sinusoidal motion models without stochastic components compare very favorably with the ITRF2005 solution. Filtering strategies and time series results using ITRF2005 and ITRF2008 input data will be presented.

  20. Complete internal audit of a mammography service in a reference institution for breast imaging*

    PubMed Central

    Badan, Gustavo Machado; Roveda Júnior, Décio; Ferreira, Carlos Alberto Pecci; de Noronha Junior, Ozeas Alves

    2014-01-01

    Objective Undertaking of a complete audit of the service of mammography, as recommended by BI-RADS®, in a private reference institution for breast cancer diagnosis in the city of São Paulo, SP, Brazil, and comparison of results with those recommended by the literature. Materials and Methods Retrospective, analytical and cross-sectional study including 8,000 patients submitted to mammography in the period between April 2010 and March 2011, whose results were subjected to an internal audit. The patients were followed-up until December 2012. Results The radiological classification of 7,249 screening mammograms, according to BI-RADS, was the following: category 0 (1.43%), 1 (7.82%), 2 (80.76%), 3 (8.35%), 4 (1.46%), 5 (0.15%) and 6 (0.03%). The breast cancer detection ratio was 4.8 cases per 1,000 mammograms. Ductal carcinoma in situ was found in 22.8% of cases. Positive predictive values for categories 3, 4 and 5 were 1.3%, 41.3% and 100%, respectively. In the present study, the sensitivity of the method was 97.1% and specificity, 97.4%. Conclusion The complete internal audit of a service of mammography is essential to evaluate the quality of such service, which reflects on an early breast cancer detection and reduction of mortality rates. PMID:25741052

  1. Exposure limits for nanoparticles: report of an international workshop on nano reference values.

    PubMed

    van Broekhuizen, Pieter; van Veelen, Wim; Streekstra, Willem-Henk; Schulte, Paul; Reijnders, Lucas

    2012-07-01

    This article summarizes the outcome of the discussions at the international workshop on nano reference values (NRVs), which was organized by the Dutch trade unions and employers' organizations and hosted by the Social Economic Council in The Hague in September 2011. It reflects the discussions of 80 international participants representing small- and medium-size enterprises (SMEs), large companies, trade unions, governmental authorities, research institutions, and non-governmental organizations (NGOs) from many European countries, USA, India, and Brazil. Issues that were discussed concerned the usefulness and acceptability of precaution-based NRVs as a substitute for health-based occupational exposure limits (OELs) and derived no-effect levels (DNELs) for manufactured nanoparticles (NPs). Topics concerned the metrics for measuring NPs, the combined exposure to manufactured nanomaterials (MNMs) and process-generated NPs, the use of the precautionary principle, the lack of information about the presence of nanomaterials, and the appropriateness of soft regulation for exposure control. The workshop concluded that the NRV, as an 8-h time-weighted average, is a comprehensible and useful instrument for risk management of professional use of MNMs with a dispersible character. The question remains whether NRVs, as advised for risk management by the Dutch employers' organization and trade unions, should be under soft regulation or that a more binding regulation is preferable. PMID:22752096

  2. Comprehensive Comparison of an Ionospheric Data Assimilation Model and the International Reference Ionosphere

    NASA Astrophysics Data System (ADS)

    Meehan, J.; Tobiska, W.; Schunk, R. W.; Scherliess, L.; Gardner, L. C.

    2012-12-01

    Ionospheric parameters from the Utah State University (USU) Global Assimilation of Ionospheric Measurement Gauss-Markov (GAIM-GM) model are compared to those obtained from International Reference Ionosphere (IRI). The GAIM-GM model is run to provide both specification and forecasts of the ionosphere; however, for this study historical runs will be used from GAIM-GM. Validation and testing versions of GAIM-GM are run in the Space Weather Center at USU. The IRI is an empirical model that is the international standard for the specification of ionospheric parameters based on a wide range of worldwide measurements from ground-based and satellite observations. The comparison of GAIM-GM and the IRI will primarily be via the peak electron density (NmF2) and the peak height (hmF2) over North America. Comparisons will be shown for high, medium and low solar activity, for the summer and winter solstices, and the fall and spring equinoxes. Comparisons will also be shown for different magnetic activity levels.

  3. Evolution of the Proposed International Tropical Reference Atmosphere up to 2000 km

    NASA Astrophysics Data System (ADS)

    Ananthasayanam, M.

    There is a compelling need in many aerospace, remote sensing, and other applications to propose a global reference atmosphere encompassing the whole of the tropics, due to the following reasons among others. The tropics cover a large area and the atmospheric conditions there are quite different from those in the midlatitudes represented by the International Standard Atmosphere. Though the dictionary definition of the tropics is between 230 28' N and 230 28' S, there can be no sharp dividing line between the tropics and extra tropics, and dynamical considerations suggest 30 0 N and 300 S as more appropriate approximate boundaries. (During summer tropical conditions prevail up to about 350 N). The early work of Ramanathan in 1929 pointed out that a break in the temperature distribution occurs around 16 km at low latitudes, whereas it occurs at much lower altitudes (around 11 km) in the temperate zone. He also showed that the coldest air over the earth (temperature about 1850 K) is in the form of a flat ring at a height of some 17 km over the equator; thus while mean temperatures are higher at sea level in the tropics, they are lower at altitudes around 15 km. Pisharoty suggested in 1959 two standard atmospheres one for the Asiatic tropics and another called Universal up to 20 km. The slight differences between these two turned out to be not valid from later measurements. Based on the presently available data showing weak longitudinal variations, it indeed turns out to be possible to provide an International Tropical Reference Atmosphere (ITRA) representative of the whole of the tropical region in both the northern and southern hemispheres (Ananthasayanam and Narasimha 1990). This proposal is also consistent with the mean monthly reference atmospheres for the northern hemisphere by Cole and Kantor (1978) and for the southern hemisphere by Koshelkov (1985) and also the Nimbus satellite data of Barnett and Corney (1985) from sea level up to 80 km. For ITRA, either the

  4. Geomagnetic polarity transitions

    NASA Astrophysics Data System (ADS)

    Merrill, Ronald T.; McFadden, Phillip L.

    1999-05-01

    The top of Earth's liquid outer core is nearly 2900 km beneath Earth's surface, so we will never be able to observe it directly. This hot, dense, molten iron-rich body is continuously in motion and is the source of Earth's magnetic field. One of the most dynamic manifestations at Earth's surface of this fluid body is, perhaps, a reversal of the geomagnetic field. Unfortunately, the most recent polarity transition occurred at about 780 ka, so we have never observed a transition directly. It seems that a polarity transition spans many human lifetimes, so no human will ever witness the phenomenon in its entirety. Thus we are left with the tantalizing prospect that paleomagnetic records of polarity transitions may betray some of the secrets of the deep Earth. Certainly, if there are systematics in the reversal process and they can be documented, then this will reveal substantial information about the nature of the lowermost mantle and of the outer core. Despite their slowness on a human timescale, polarity transitions occur almost instantaneously on a geological timescale. This rapidity, together with limitations in the paleomagnetic recording process, prohibits a comprehensive description of any reversal transition both now and into the foreseeable future, which limits the questions that may at this stage be sensibly asked. The natural model for the geomagnetic field is a set of spherical harmonic components, and we are not able to obtain a reliable model for even the first few harmonic terms during a transition. Nevertheless, it is possible, in principle, to make statements about the harmonic character of a geomagnetic polarity transition without having a rigorous spherical harmonic description of one. For example, harmonic descriptions of recent geomagnetic polarity transitions that are purely zonal can be ruled out (a zonal harmonic does not change along a line of latitude). Gleaning information about transitions has proven to be difficult, but it does seem

  5. Method of detecting abnormality in a reference crank angle position detection system of an internal combustion engine

    SciTech Connect

    Suzuki, Y.

    1987-05-12

    A method is described of detecting abnormality in a reference crank angle position detection system of a control system for controlling an internal combustion engine. The method comprises a crankshaft, the control system using at least reference pulses generated, respectively, at predetermined crank angles of the crankshaft and detected by the reference crank angle position detection system. Crank angle pulses are generated, respectively, at other predetermined angles of the crankshaft and with a pulse repetition period shorter than that of the reference pulses, for controlling the engine.

  6. Absolute Quantification of Lipophilic Shellfish Toxins by Quantitative Nuclear Magnetic Resonance Using Removable Internal Reference Substance with SI Traceability.

    PubMed

    Kato, Tsuyoshi; Saito, Maki; Nagae, Mika; Fujita, Kazuhiro; Watai, Masatoshi; Igarashi, Tomoji; Yasumoto, Takeshi; Inagaki, Minoru

    2016-01-01

    Okadaic acid (OA), a lipophilic shellfish toxin, was accurately quantified using quantitative nuclear magnetic resonance with internal standards for the development of an authentic reference standard. Pyridine and the residual proton in methanol-d4 were used as removable internal standards to limit any contamination. They were calibrated based on a maleic acid certified reference material. Thus, the concentration of OA was traceable to the SI units through accurate quantitative NMR with an internal reference substance. Signals from the protons on the oxygenated and unsaturated carbons of OA were used for quantification. A reasonable accuracy was obtained by integrating between the lower and upper (13)C satellite signal range when more than 4 mg of OA was used. The best-determined purity was 97.4% (0.16% RSD) when 20 mg of OA was used. Dinophysistoxin-1, a methylated analog of OA having an almost identical spectrum, was also quantified by using the same methodology. PMID:27396652

  7. In vitro drug susceptibility of 40 international reference rapidly growing mycobacteria to 20 antimicrobial agents

    PubMed Central

    Pang, Hui; Li, Guilian; Wan, Li; Jiang, Yi; Liu, Haican; Zhao, Xiuqin; Zhao, Zhongfu; Wan, Kanglin

    2015-01-01

    Rapidly growing mycobacteria (RGM) are human pathogens that are relatively easily identified by acid-fast staining but are proving difficult to treat in the clinic. In this study, we performed susceptibility testing of 40 international reference RGM species against 20 antimicrobial agents using the cation-adjusted Mueller-Hinton (CAMH) broth microdilution based on the minimum inhibitory concentration (MIC) assay recommended by the guidelines of the Clinical and Laboratory Standards Institute (CLSI). The results demonstrated that RGM organisms were resistant to the majority of first-line antituberculous agents but not to second-line fluoroquinolones or aminoglycosides. Three drugs (amikacin, tigecycline and linezolid) displayed potent antimycobacterial activity against all tested strains. Capreomycin, levofloxacin and moxifloxacin emerged as promising candidates for the treatment of RGM infections, and cefoxitin and meropenem were active against most strains. Mycobacterium chelonae (M. chelonae), M. abscessus, M. bolletii, M. fortuitum, M. boenickei, M. conceptionense, M. pseudoshottsii, M. septicum and M. setense were the most resistant RGM species. These results provide significant insight into the treatment of RGM species and will assist optimization of clinical criteria. PMID:26629031

  8. The ICRF-3: Proposed Roadmap to the Next Generation International Celestial Reference Frame

    NASA Astrophysics Data System (ADS)

    Jacobs, Christopher S.; Arias, F.; Boboltz, D.; Boehm, J.; Bolotin, S.; Bourda, G.; Charlot, P.; de Witt, A.; Fey, A.; Gaume, R.; Gordon, D.; Heinkelmann, R.; Lambert, S.; Ma, C.; Malkin, Z.; Nothnagel, A.; Seitz, M.; Skurikhina, E.; Souchay, J.; Titov, O.

    2013-09-01

    We propose a 3rd generation radio-based International Celestial Reference Frame (ICRF- 3) to improve upon the highly successful ICRF-2. Our goals are to improve the precision, spatial and frequency coverages relative to the ICRF-2 by 2018. This date is driven by the desire to create radio frames early enough to test the Gaia optical frame during its construction. Several specific actions are underway. A collaboration has been started to improve S/X-band precision of the 2000+ VLBA Calibrator Survey sources which are typically 5 times less precise than the rest of the ICRF-2. S/X-band southern precision improvements are planned from observations with southern antennas such as the AuScope and HartRAO, S. Africa. We seek to improve radio frequency coverage with X/Ka and K- band work. An X/Ka frame of 631 sources now has full sky coverage from the addition of a 2nd southern station in Argentina which should strengthen the southern hemisphere in general. A K-band collaboration has formed with similar coverage and southern precision goals. On the analysis front, special attention will be given to combination techniques both of VLBI catalogs and of multiple data types (e.g. VLBI+GPS). Finally, work is underway to identify and pinpoint sources bright enough in both radio and optical to allow for a robust frame tie between VLBI and Gaia optical frames.

  9. Preparation and validation of the first WHO international genetic reference panel for Fragile X syndrome

    PubMed Central

    Hawkins, Malcolm; Boyle, Jennifer; Wright, Kathleen E; Elles, Rob; Ramsden, Simon C; O'Grady, Anna; Sweeney, Michael; Barton, David E; Burgess, Trent; Moore, Melanie; Burns, Chris; Stacey, Glyn; Gray, Elaine; Metcalfe, Paul; Hawkins, J Ross

    2011-01-01

    Fragile X syndrome is the most common inherited form of mental retardation. It is caused by expansion of a trinucleotide (CGG)n repeat sequence in the 5′ untranslated region of the FMR1 gene, resulting in promoter hypermethylation and suppression of FMR1 transcription. Additionally, pre-mutation alleles in carrier males and females may result in Fragile X tremor ataxia syndrome and primary ovarian insufficiency, respectively. Fragile X is one of the most commonly requested molecular genetic tests worldwide. Quality assessment schemes have identified a wide disparity in allele sizing between laboratories. It is therefore important that clinical laboratories have access to characterized reference materials (RMs) to aid accurate allele sizing and diagnosis. With this in mind, a panel of genotyping RMs for Fragile X syndrome has been developed, which should be stable over many years and available to all diagnostic laboratories. Immortalized cell lines were produced by Epstein–Barr virus transformation of lymphocytes from consenting patients. Genomic DNA was extracted in bulk and RM aliquots were freeze-dried in glass ampoules. Twenty-one laboratories from seventeen countries participated in a collaborative study to assess their suitability. Participants evaluated the samples (blinded, in triplicate) in their routine methods alongside in-house and commercial controls. The panel of five genomic DNA samples was endorsed by the European Society of Human Genetics and approved as an International Standard by the Expert Committee on Biological Standardization at the World Health Organization. PMID:20736975

  10. CSNI Project for Fracture Analyses of Large-Scale International Reference Experiments (Project FALSIRE)

    SciTech Connect

    Bass, B.R.; Pugh, C.E.; Keeney-Walker, J.; Schulz, H.; Sievers, J.

    1993-06-01

    This report summarizes the recently completed Phase I of the Project for Fracture Analysis of Large-Scale International Reference Experiments (Project FALSIRE). Project FALSIRE was created by the Fracture Assessment Group (FAG) of Principal Working Group No. 3 (PWG/3) of the Organization for Economic Cooperation and Development (OECD)/Nuclear Energy Agency`s (NEA`s) Committee on the Safety of Nuclear Installations (CSNI). Motivation for the project was derived from recognition by the CSNI-PWG/3 that inconsistencies were being revealed in predictive capabilities of a variety of fracture assessment methods, especially in ductile fracture applications. As a consequence, the CSNI/FAG was formed to evaluate fracture prediction capabilities currently used in safety assessments of nuclear components. Members are from laboratories and research organizations in Western Europe, Japan, and the United States of America (USA). On behalf of the CSNI/FAG, the US Nuclear Regulatory Commission`s (NRC`s) Heavy-Section Steel Technology (HSST) Program at the Oak Ridge National Laboratory (ORNL) and the Gesellschaft fuer Anlagen--und Reaktorsicherheit (GRS), Koeln, Federal Republic of Germany (FRG) had responsibility for organization arrangements related to Project FALSIRE. The group is chaired by H. Schulz from GRS, Koeln, FRG.

  11. F region electron density profile inversion from backscatter ionogram based on international reference ionosphere

    NASA Astrophysics Data System (ADS)

    Zhu, Peng; Zhou, Chen; Zhang, Yuannong; Yang, Guobin; Jiang, Chunhua; Sun, Hengqing; Cui, Xiao

    2015-07-01

    Ionospheric backscatter sounding transmits HF (3-30 MHz) radio wave obliquely into ionosphere and receives echoes backscattered from remote ground. Due to the focusing effect, the echoes form leading edge on the swept frequency backscatter ionogram (BSI). This kind of backscatter ionogram contains plentiful ionospheric information, such as electron density, radio wave propagation modes and maximum usage frequency (MUF). By inversion algorithm, the backscatter ionogram can provide two-dimensional electron density profile (EDP) down range. In this paper, we propose an ionospheric F2 region EDP inversion algorithm. By utilizing the F2 bottomside electron density profile represented by the International Reference Ionosphere (IRI) model and ray tracing techniques, this approach inverts the leading edge of the backscatter ionogram to two dimensional F region EDP. Results of validation experiments demonstrate that the inverted ionospheric EDPs show good agreement with the results of vertical ionosonde and provide reliable information of ionosphere. Thus the proposed inversion algorithm provide an effective and accurate method for achieving large scale and remote ionospheric electron density structure.

  12. An Internal Reference Control Duplex Real-Time Polymerase Chain Reaction Assay for Detecting Bacterial Contamination in Blood Products.

    PubMed

    Zhang, Jin-Ju; Tian, Jing-Jing; Wei, Shuang-Shi; Duan, Sheng-Bao; Wang, Hong-Mei; Chen, Ye-Zhou; Ding, Shao-Hua; Zhang, Chun; Meng, Qing-Lin; Li, Yong

    2015-01-01

    Real-time polymerase chain reaction (RT-PCR) enables effective and sensitive screening for infectious risk in the field of blood safety. However, when using RT-PCR to detect bacterial contamination, several intractable points must be considered, one of which is the lack of appropriate quality control. In this study, we developed a simplified RT-PCR assay in which the same primer set and two distinct probes were used to detect both, an internal reference control and the target in a reaction. The copy number of the internal reference control represents the positive detection limit of the assay; therefore, when the threshold-cycle value of the target is less than or equal to that of the internal reference control, the result obtained for the target can be considered to be a true positive. When human gDNA was spiked with Escherichia coli gDNA and the detection limit for the internal reference control was set to five copies, the measured detection limit for E. coli gDNA was two copies. The internal reference control duplex RT-PCR assay showed high efficiency (0.91-1.02), high linearity (R2 > 0.99), and good reproducibility in intra- and inter-assay comparisons. Lastly, when human platelet-rich plasma samples were spiked with E. coli or other bacterial species, all species were detected efficiently, and the results of a two-sample pooled t test showed that the limit of detection for E. coli was 1 cfu/mL. Here, we present a synthetic internal reference control molecule and a new statistical method for improving the reliability of RT-PCR assays when screening for bacterial contamination in blood products. PMID:26230627

  13. Geomagnetic storms prediction from InterMagnetic Observatories data using the Multilayer Perceptron neural network

    NASA Astrophysics Data System (ADS)

    Ouadfeul, S.; Aliouane, L.; Tourtchine, V.

    2013-09-01

    In this paper, a tentative of geomagnetic storms prediction is implanted by analyzing the International Real-Time Magnetic Observatory Network data using the Artificial Neural Network (ANN). The implanted method is based on the prediction of future horizontal geomagnetic field component using a Multilayer Perceptron (MLP) neural network model. The input is the time and the output is the X and Y magnetic field components. Application to geomagnetic data of Mai 2002 shows that the implanted ANN model can greatly help the geomagnetic storms prediction.

  14. Expanding Spatial Coverage of Geomagnetic Field Models Using Submarine Basaltic Glass

    NASA Astrophysics Data System (ADS)

    Schoeller, L. M.; Bowles, J. A.; Dreyer, B.; Clague, D. A.

    2009-12-01

    In recent years, paleointensity of submarine basaltic glass (SBG) has been used to constrain the ages of young mid-ocean ridge flows, often in the absence of more precise age data. In the present study, samples taken from the Co-Axial segment of the Juan de Fuca Ridge allow for further testing of the paleointensity dating technique; they also provide an assessment of the feasibility of incorporating SBG data into geomagnetic field models when independent age constraints are available. The nine sampled sites include six for which 14C dating of overlying sediments provides minimum ages (950 - 6400 ybp) for the flows, and three sites from historical flows. Absolute paleointensity estimates were derived using a Thellier-type method. The paleointensities of the samples ranged from 51.8 µT to 71.1 µT (VADM 8.3 to 11.6 x 1022 Am2). We compare results from the young (historical) flows directly with the International Geomagnetic Reference Field (IGRF), and two out of three sites are consistent with IGRF. The third gives paleointensity values that are considerably higher than would be expected based on IGRF. The rest of the samples can be compared with geomagnetic field models based on archeomagnetic and paleomagnetic data. Paleointensity values from samples < 3ka are consistent with the CALS3K.3 model (Korte et al., Geochem. Geophys. Geosys., 10, Q06008, doi:10.1029/2008GC002297, 2009), given the approximate ages provided by the 14C dating of the overlying sediments. Data constraining current geomagnetic field models are spatially quite limited, with the vast majority restricted to northern hemispheric continental regions. We suggest that data from mid-ocean ridges are suitable for incorporation into such models, with the potential to greatly expand spatial coverage.

  15. The contribution of L'Aquila (Italy) Geomagnetic Observatory to MAGDAS project

    NASA Astrophysics Data System (ADS)

    Lepidi, S.; Meloni, A.; Palangio, P.; Yumoto, K.

    2011-12-01

    The geomagnetic Observatory of L'Aquila (Italy) was founded by Istituto Nazionale di Geofisica e Vulcanologia (INGV) in 1958, on the occasion of the International Geophysical Year. It is the main Italian geomagnetic observatory. Since 1999 L'Aquila Observatory belongs to the Intermagnet system, an International network grouping worldwide geomagnetic observatories able to provide Earth's magnetic field measurements according to precise quality standards. Geomagnetic field measurements in L'Aquila are used to study the variations of the Earth's geomagnetic field, both of internal and external origin. In November 2008 a new magnetometer was installed in L'Aquila within the MAGDAS project, coordinated by SERC. The location of this installation can be useful to complete the MAGDAS monitoring system to study solar-terrestrial events.

  16. Space-time structure of the 2003 geomagnetic jerk at Mid-Eastern Asia

    NASA Astrophysics Data System (ADS)

    Ou, Jiaming; Du, Aimin; Xu, Wenyao; Yang, Dongmei

    2015-04-01

    The 2003 jerk has an abrupt change in the geomagnetic secular variation (SV), and was recognized as a local phenomenon of internal origin from the satellite observations (Olsen and Mandea, 2007). Notable strength of the 2003 jerk is located at Mid-Eastern Asia. The temporal and spatial features at this area are important to resolve the Earth's core fluid flow dynamics at local scale (e.g. Wardinski et al., 2008). We investigate the temporal-spatial development of the 2003 jerk in more detail at Mid-Eastern Asia with the ground-based observations and CHAOS-3 core field model. We select the data in the international geomagnetic quiet days to calculate the monthly means. In order to reduce the influence of the external field, we adopt a function comprising the terms associated with the indices of the geomagnetic activity, and the terms of the periodic signals on the observatory monthly means data (Stewart and Whaler, 1992). We then use an empirical AR-2 model to represent the internal field signals in the observatory data. The extreme detection is applied to identify the jerk in the SV time series. The onset time and the strength of the 2003 jerk are obtained through the detection for geomagnetic field component, X, Y and Z. The maximum of the strength of the 2003 jerk is located under the Indian mainland. The onset time of this jerk propagates approximately southeastward. Two jerks in 2001 and 2003 for the Z component are further compared and they are confirmed as independent processes. We suggest the jerk in 2001 identical to the well known 1999 jerk in Europe (Mandea et al., 2000). Our results reveal the fine structures of the 2003 jerk that corroborate the conclusions in previous studies. The larger scale time-spatial structure given by the AR-2 model constructed from ground observatory data (monthly values) is consistent with the results from the CHAOS-3 model. This structure can be applied for further inversion of the local core surface fluid flow motions

  17. Domino model for geomagnetic field reversals.

    PubMed

    Mori, N; Schmitt, D; Wicht, J; Ferriz-Mas, A; Mouri, H; Nakamichi, A; Morikawa, M

    2013-01-01

    We solve the equations of motion of a one-dimensional planar Heisenberg (or Vaks-Larkin) model consisting of a system of interacting macrospins aligned along a ring. Each spin has unit length and is described by its angle with respect to the rotational axis. The orientation of the spins can vary in time due to spin-spin interaction and random forcing. We statistically describe the behavior of the sum of all spins for different parameters. The term "domino model" in the title refers to the interaction among the spins. We compare the model results with geomagnetic field reversals and dynamo simulations and find strikingly similar behavior. The aggregate of all spins keeps the same direction for a long time and, once in a while, begins flipping to change the orientation by almost 180 degrees (mimicking a geomagnetic reversal) or to move back to the original direction (mimicking an excursion). Most of the time the spins are aligned or antialigned and deviate only slightly with respect to the rotational axis (mimicking the secular variation of the geomagnetic pole with respect to the geographic pole). Reversals are fast compared to the times in between and they occur at random times, both in the model and in the case of the Earth's magnetic field. PMID:23410284

  18. Establishment of the first WHO Erythropoietin antibody reference panel: Report of an international collaborative study.

    PubMed

    Wadhwa, Meenu; Mytych, Daniel T; Bird, Chris; Barger, Troy; Dougall, Thomas; Han, Hong; Rigsby, Peter; Kromminga, Arno; Thorpe, Robin

    2016-08-01

    A panel of 9 fully human monoclonal antibodies against human erythropoietin (EPO) with defined characteristics (non-neutralizing, neutralizing, various isotypes, affinities) representative of those evident in antibody-mediated pure red cell aplasia (PRCA) and non-PRCA patients were formulated and lyophilized. The panel was evaluated in a multi-centre international collaborative study comprising eighteen different laboratories using different assay platforms including those in routine use. These included binding assays, some based on use of novel technologies and neutralization assays predominantly employing EPO responsive cell-lines. Results showed that detection and titre varied depending on antibody characteristics and the method used. Only selective assay platforms were capable of detecting the diverse repertoire of EPO antibodies in the panel indicating that some clinically relevant antibodies are likely to be missed in some assays. Importantly, the clinical samples from PRCA patients were distinguished as antibody-positive and the healthy donor serum as antibody negative across all different platforms tested. For neutralization, data was generally consistent across the assays for the different samples regardless of the cell-line and the assay conditions. The heterogeneity in data from the study clearly indicated the need for reference standards for consistency in detecting and measuring EPO antibodies across different assay platforms for monitoring the safety and efficacy of erythropoiesis stimulating agents. Therefore, the WHO ECBS at its meeting in October'15 established the EPO antibody panel, available from NIBSC, to facilitate decision-making on assay selection for testing antibodies against human EPO, for evaluating assay performance of antibody assays for clinical use, for assay validation and for standardization. PMID:27173074

  19. Internalizing Symptoms and Affective Reactivity in Relation to the Severity of Aggression in Clinically Referred, Behavior-Disordered Children

    ERIC Educational Resources Information Center

    Kolko, David J.; Baumann, Barbara L.; Bukstein, Oscar G.; Brown, Elissa J.

    2007-01-01

    We examined the affective correlates of aggression in children referred to a partial hospitalization program for the treatment of behavior disorders who did not have a mood or anxiety disorder. Parent and teacher ratings of the children's impulsivity, internalizing symptoms, affective reactivity, and aggression were examined for their…

  20. Selected Bibliographies for Pharmaceutical Supply Systems. Volume 5: Pharmaceutical Supply Systems Bibliographies. International Health Planning Reference Series.

    ERIC Educational Resources Information Center

    Schaumann, Leif

    Intended as a companion piece to volume 7 in the Method Series, Pharmaceutical Supply System Planning (CE 024 234), this fifth of six volumes in the International Health Planning Reference Series is a combined literature review and annotated bibliography dealing with alternative methodologies for planning and analyzing pharmaceutical supply…

  1. Verbal and Math Self-Concepts: An Extension of the Internal/External Frame of Reference Model.

    ERIC Educational Resources Information Center

    Marsh, Herbert W.; Byrne, Barbara M.

    The internal/external (I/E) frame of reference model describes relations among Verbal self-concept (VSC), Math self-concept (MSC), and corresponding achievement scores (VACH, MACH). In support of the model Marsh (1986) found that: (1) VSC and MSC were nearly uncorrelated; (2) the effect of VACH on VSC, and of MACH on MSC, were positive; but (3)…

  2. Cognitive Ability, Academic Achievement and Academic Self-Concept: Extending the Internal/External Frame of Reference Model

    ERIC Educational Resources Information Center

    Chen, Ssu-Kuang; Hwang, Fang-Ming; Yeh, Yu-Chen; Lin, Sunny S. J.

    2012-01-01

    Background: Marsh's internal/external (I/E) frame of reference model depicts the relationship between achievement and self-concept in specific academic domains. Few efforts have been made to examine concurrent relationships among cognitive ability, achievement, and academic self-concept (ASC) within an I/E model framework. Aim: To simultaneously…

  3. Bayesian inference in geomagnetism

    NASA Technical Reports Server (NTRS)

    Backus, George E.

    1988-01-01

    The inverse problem in empirical geomagnetic modeling is investigated, with critical examination of recently published studies. Particular attention is given to the use of Bayesian inference (BI) to select the damping parameter lambda in the uniqueness portion of the inverse problem. The mathematical bases of BI and stochastic inversion are explored, with consideration of bound-softening problems and resolution in linear Gaussian BI. The problem of estimating the radial magnetic field B(r) at the earth core-mantle boundary from surface and satellite measurements is then analyzed in detail, with specific attention to the selection of lambda in the studies of Gubbins (1983) and Gubbins and Bloxham (1985). It is argued that the selection method is inappropriate and leads to lambda values much larger than those that would result if a reasonable bound on the heat flow at the CMB were assumed.

  4. Proceedings of the 127th Colloquium of the International Astronomical Union Reference Systems

    NASA Astrophysics Data System (ADS)

    Hughes, James A.; Smith, Clayton A.; Kaplan, George H.

    Both invited oral and poster papers were presented on topics ranging from theoretical relativistic considerations to new observational programs and results. Partial contents include a report of the Subgroup on Time; preliminary report of the work of the Subgroup on Coordinate Frames and Origins; activity report of the IAU Working Group on reference system: subgroup on astronomical constants; relativistic hierarchy of reference systems and time scales; relativistic celestial mechanics and reference frames; current status of the astrometric capabilities of the Hubble Space Telescope fine guidance sensors; necessary procedures to reach an agreeable reference frame: counterproposal to the circular letter no. 4 of Kovalevsky; stability of the extragalactic reference frame realized by VLBI; The ZMOA-1990 nutation series; and long-period perturbations in terrestrial reference frames.

  5. Effects of magnetic fields produced by simulated and real geomagnetic storms on rats

    NASA Astrophysics Data System (ADS)

    Martínez-Bretón, J. L.; Mendoza, B.

    2016-03-01

    In this paper we report experiments of arterial pressure (AP) measurements of ten Wistar rats subjected to geomagnetic field changes and to artificially stimulated magnetic field variations. Environmental electromagnetic effects were screened using a semianechoic chamber, which allowed us to discern the effects associated with geomagnetic storms. We stimulated the subjects with a linear magnetic profile constructed from the average changes of sudden storm commencement (SSC) and principal phases of geomagnetic storms measured between 1996 and 2008 with Dst ⩽ -100 nT. Although we found no statistically significant AP variations, statistically significant AP changes were found when a geomagnetic storm occurred during the experimental period. Using the observed geomagnetic storm variations to construct a geomagnetic profile to stimulate the rats, we found that the geomagnetic field variations associated to the SSC day were capable of increasing the subjects AP between 7% and 9% from the reference value. Under this magnetic variation, the subjects presented a notably restless behavior not seen under other conditions. We conclude that even very small changes in the geomagnetic field associated with a geomagnetic storm can produce a measurable and reproducible physiological response.

  6. Geomagnetic Reversals during the Phanerozoic.

    PubMed

    McElhinny, M W

    1971-04-01

    An antalysis of worldwide paleomagnetic measurements suggests a periodicity of 350 x 10(6) years in the polarity of the geomagnetic field. During the Mesozoic it is predominantly normal, whereas during the Upper Paleozoic it is predominantly reversed. Although geomagnetic reversals occur at different rates throughout the Phanerozoic, there appeaars to be no clear correlation between biological evolutionary rates and reversal frequency. PMID:17735224

  7. Simulation of the geomagnetic field experienced by the International Space Station in its revolution around the Earth: Effects on psychophysiological responses to affective picture viewing

    NASA Astrophysics Data System (ADS)

    Del Seppia, C.; Mezzasalma, L.; Messerotti, M.; Cordelli, A.; Ghione, S.

    2006-02-01

    There is evidence suggesting that exposure to an abnormal magnetic environment may produce psychophysiological effects related to abnormalities in responses to stress. This may be of relevance for space medicine where astronauts are exposed to a magnetic field different from that exerted by the Earth. Aim of this study was to assess how the exposure of the head to a magnetic field simulating the one encountered by the International Space Station (ISS) during a single orbit (90 min) around the Earth affects the cardiovascular and psychophysiological parameters. Twenty-four human volunteers were studied double blindly in random order under sham and magnetic exposure. During exposure, the persons were shown a set of pictures of different emotional content while subjective self-rating, skin conductance (SC), blood pressure (BP), and heart rate (HR) were measured. In addition, BP, HR, and tooth pain threshold were assessed before and after exposure. While subjects were under magnetic exposure, skin conductance was strongly differentiated (F|2,36 = 22.927; p = 0.0001), being high during emotionally involving (positive and negative) pictures and low during neutral pictures. Conversely, when subjects were under sham exposure, no significant differences were observed. There was, however, a trend for higher heart rate during picture viewing under magnetic exposure as compared to sham exposure. No effects were found for the other variables. These results suggest that an abnormal magnetic field that simulates the one encountered by ISS orbiting around the Earth may enhance autonomic response to emotional stimuli.

  8. Simulation of the geomagnetic field experienced by the International Space Station in its revolution around the Earth: effects on psychophysiological responses to affective picture viewing.

    PubMed

    Del Seppia, Cristina; Mezzasalma, Lorena; Messerotti, Mauro; Cordelli, Alessandro; Ghione, Sergio

    2006-06-12

    There is evidence suggesting that exposure to an abnormal magnetic environment may produce psychophysiological effects related to abnormalities in responses to stress. This may be of relevance for space medicine where astronauts are exposed to a magnetic field different from that exerted by the Earth. Aim of this study was to assess how the exposure of the head to a magnetic field simulating the one encountered by the International Space Station (ISS) during a single orbit (90 min) around the Earth affects the cardiovascular and psychophysiological parameters. Twenty-four human volunteers were studied double blindly in random order under sham and magnetic exposure. During exposure, the persons were shown a set of pictures of different emotional content while subjective self-rating, skin conductance (SC), blood pressure (BP), and heart rate (HR) were measured. In addition, BP, HR, and tooth pain threshold were assessed before and after exposure. While subjects were under magnetic exposure, skin conductance was strongly differentiated (F(2,36)=22.927; p=0.0001), being high during emotionally involving (positive and negative) pictures and low during neutral pictures. Conversely, when subjects were under sham exposure, no significant differences were observed. There was, however, a trend for higher heart rate during picture viewing under magnetic exposure as compared to sham exposure. No effects were found for the other variables. These results suggest that an abnormal magnetic field that simulates the one encountered by ISS orbiting around the Earth may enhance autonomic response to emotional stimuli. PMID:16529860

  9. The International GPS Service (IGS) as a Continuous Reference System for Precise GPS Positioning

    NASA Technical Reports Server (NTRS)

    Neilan, Ruth; Heflin, Michael; Watkins, Michael; Zumberge, James

    1996-01-01

    The International GPS Service for Geodynamics (IGS) is an organization which operates under the auspices of the International Association of Geodesy (IAG) and has been operational since January 1994. The primary objective of the IGS is to provide precise GPS data and data products to support geodetic and geophysical research activities.

  10. An International Strategy for Human Exploration of the Moon: The International Space Exploration Coordination Group (ISECG) Reference Architecture for Human Lunar Exploration

    NASA Technical Reports Server (NTRS)

    Laurini, Kathleen C.; Hufenbach, Bernhard; Junichiro, Kawaguchi; Piedboeuf, Jean-Claude; Schade, Britta; Lorenzoni, Andrea; Curtis, Jeremy; Hae-Dong, Kim

    2010-01-01

    The International Space Exploration Coordination Group (ISECG) was established in response to The Global Exploration Strategy: The Framework for Coordination developed by fourteen space agencies and released in May 2007. Several ISECG participating space agencies have been studying concepts for human exploration of the moon that allow individual and collective goals and objectives to be met. This 18 month study activity culminated with the development of the ISECG Reference Architecture for Human Lunar Exploration. The reference architecture is a series of elements delivered over time in a flexible and evolvable campaign. This paper will describe the reference architecture and how it will inform near-term and long-term programmatic planning within interested agencies. The reference architecture is intended to serve as a global point of departure conceptual architecture that enables individual agency investments in technology development and demonstration, International Space Station research and technology demonstration, terrestrial analog studies, and robotic precursor missions to contribute towards the eventual implementation of a human lunar exploration scenario which reflects the concepts and priorities established to date. It also serves to create opportunities for partnerships that will support evolution of this concept and its eventual realization. The ISECG Reference Architecture for Human Lunar Exploration (commonly referred to as the lunar gPoD) reflects the agency commitments to finding an effective balance between conducting important scientific investigations of and from the moon, as well as demonstrating and mastering the technologies and capabilities to send humans farther into the Solar System. The lunar gPoD begins with a robust robotic precursor phase that demonstrates technologies and capabilities considered important for the success of the campaign. Robotic missions will inform the human missions and buy down risks. Human exploration will start

  11. a Millennium of Geomagnetism

    NASA Astrophysics Data System (ADS)

    Stern, David P.

    2002-11-01

    The history of geomagnetism began around the year 1000 with the discovery in China of the magnetic compass. Methodical studies of the Earth's field started in 1600 with William Gilbert's De Magnete [Gilbert, 1600] and continued with the work of (among others) Edmond Halley, Charles Augustin de Coulomb, Carl Friedrich Gauss, and Edward Sabine. The discovery of electromagnetism by Hans Christian Oersted and André-Marie Ampére led Michael Faraday to the notion of fluid dynamos, and the observation of sunspot magnetism by George Ellery Hale led Sir Joseph Larmor in 1919 to the idea that such dynamos could sustain themselves naturally in convecting conducting fluids. From that came modern dynamo theory, of both the solar and terrestrial magnetic fields. Paleomagnetic studies revealed that the Earth's dipole had undergone reversals in the distant past, and these became the critical evidence in establishing plate tectonics. Finally, the recent availability of scientific spacecraft has demonstrated the intricacy of the Earth's distant magnetic field, as well as the existence of magnetic fields associated with other planets and with satellites in our solar system.

  12. 18O-Labeled Proteome Reference as Global Internal Standards for Targeted Quantification by Selected Reaction Monitoring-Mass Spectrometry

    SciTech Connect

    Kim, Jong Seo; Fillmore, Thomas L.; Liu, Tao; Robinson, Errol W.; Hossain, Mahmud; Champion, Boyd L.; Moore, Ronald J.; Camp, David G.; Smith, Richard D.; Qian, Weijun

    2011-10-11

    Selected reaction monitoring-mass spectrometry (SRM-MS) is an emerging technology for high throughput targeted protein quantification and verification in biological and biomarker discovery studies; however, the cost associated with the use of stable isotope labeled synthetic peptides as internal standards is prohibitive for quantitatively screening large numbers of candidate proteins as often required in the pre-verification phase of biomarker discovery. Herein we present the proof-of-concept experiments of using an 18O-labeled 'universal' reference as comprehensive internal standards for quantitative SRM-MS analysis. With an 18O-labeled whole proteome sample as reference, every peptide of interest will have its own corresponding heavy isotope labeled internal standard, thus providing an ideal approach for quantitative screening of a large number of candidates using SRM-MS. Our results showed that the 18O incorporation efficiency using a recently improved protocol was >99.5% for most peptides investigated, a level comparable to 13C/15N labeled synthetic peptides in terms of heavy isotope incorporation. The accuracy, reproducibility, and linear dynamic range of quantification were further assessed based on known ratios of standard proteins spiked into mouse plasma with an 18O-labeled mouse plasma reference. A dynamic range of four orders of magnitude in relative concentration was obtained with high reproducibility (i.e., coefficient of variance <10%) based on the 16O/18O peak area ratios. Absolute and relative quantification of C-reactive protein and prostate-specific antigen were demonstrated by coupling an 18O-labeled reference with standard additions of protein standards. Collectively, our results demonstrated that the use of 18O-labeled reference provides a convenient and effective strategy for quantitative SRM screening of large number of candidate proteins.

  13. Language and Automation. An International Reference Publication. Number 1, Spring 1970.

    ERIC Educational Resources Information Center

    Center for Applied Linguistics, Washington, DC. Language Information Network and Clearinghouse System.

    This publication is a sample issue of a new reference publication "designed to meet the growing demand for substantial, timely coverage of the literature dealing with the interfaces of linguistics, computation, information science, and related fields." Prepared by the Language Information Network and Clearinghouse System (LINCS) at the Center for…

  14. Precise determination of Cr and Co in certified reference material of silicon nitride by neutron activation analysis using internal standardization.

    PubMed

    Miura, Tsutomu; Matsue, Hideaki; Kuroiwa, Takayoshi; Chiba, Koichi

    2009-07-01

    Neutron activation analysis with an internal standard correction was applied to the determination of Cr and Co in a ceramics certified reference material (NMIJ CRM 8004-a silicon nitride powder). Cesium was used as an internal standard to compensate for any inhomogeneity of the neutron flux through an irradiation capsule and to improve the repeatability of gamma-ray measurements. It was found that the linearity of the calibration curves of Cr and Co was improved by using an internal standard. The analytical results of Cr and Co in NMIJ CRM 8004-a were in good agreement with those obtained by ICP-OES, ICP-sector field mass spectrometry (ICP-SFMS), and isotope dilution/ICP-SFMS for Cr. The relative expanded uncertainties (k = 2) were 1.9% for Cr and 1.5% for Co. The uncertainties were comparable to those of atomic spectrometric methods. PMID:19609027

  15. Microarray analysis of relative gene expression stability for selection of internal reference genes in the rhesus macaque brain

    PubMed Central

    2010-01-01

    Background Normalization of gene expression data refers to the comparison of expression values using reference standards that are consistent across all conditions of an experiment. In PCR studies, genes designated as "housekeeping genes" have been used as internal reference genes under the assumption that their expression is stable and independent of experimental conditions. However, verification of this assumption is rarely performed. Here we assess the use of gene microarray analysis to facilitate selection of internal reference sequences with higher expression stability across experimental conditions than can be expected using traditional selection methods. We recently demonstrated that relative gene expression from qRT-PCR data normalized using GAPDH, ALG9 and RPL13A expression values mirrored relative expression using quantile normalization in Robust Multichip Analysis (RMA) on the Affymetrix® GeneChip® rhesus Macaque Genome Array. Having shown that qRT-PCR and Affymetrix® GeneChip® data from the same hormone replacement therapy (HRT) study yielded concordant results, we used quantile-normalized gene microarray data to identify the most stably expressed among probe sets for prospective internal reference genes across three brain regions from the HRT study and an additional study of normally menstruating rhesus macaques (cycle study). Gene selection was limited to 575 previously published human "housekeeping" genes. Twelve animals were used per study, and three brain regions were analyzed from each animal. Gene expression stabilities were determined using geNorm, NormFinder and BestKeeper software packages. Results Sequences co-annotated for ribosomal protein S27a (RPS27A), and ubiquitin were among the most stably expressed under all conditions and selection criteria used for both studies. Higher annotation quality on the human GeneChip® facilitated more targeted analysis than could be accomplished using the rhesus GeneChip®. In the cycle study, multiple

  16. Total Geomagnetic Survey on Suruga Bay, on the Pacific cost, Shizuoka, Japan, the second series report.

    NASA Astrophysics Data System (ADS)

    Ichinose, S.; Baba, H.

    2015-12-01

    In 2009 to 2014, total geomagnetic and geological surveys by School of Marine Science & Technology, Tokai University, were conducted on Suruga Bay, located on the Pacific coast of Honshu in Shizuoka Prefecture, central Japan, where a large thrust earthquake, often referred to as the Tokai earthquake, has been supposed to occur soon (Ishibashi, 1981). Suruga Bay area, where the Philippine Sea plate subducts beneath Japan, had some local magnetic anomalies on the overriding plate side. The past investigation of ship-borne survey conducted in Suruga Bay area is geomagnetic anomaly data of the Hydrographic Department of the Maritime Safety Agency in 1997. Detailed geomagnetic surveys carried out in the Suruga Bay area, is 50 km x 35km in S-N and W-E, respectively. Total geomagnetic anomaly values range from +100nT to +600nT. In this report, we carried out newly geomagnetic survey lines which costal region on Suruga Bay. The following results were found. (1) The costal region of Izu Peninsula in Northern part of Izu-Ogasawara arc is indicated high geomagnetic anomaly. This cause is regarded as something to come near to some volcanos. (2) And costal region of the Fujigawa fault system in the Sourath Fossa Magna region is indicated high geomagnetic anomaly. We present features of total geomagnetic anomalies on and around Suruga Bay with the results of inversion.

  17. Differential School Contextual Effects for Math and English: Integrating the Big-Fish-Little-Pond Effect and the Internal/External Frame of Reference

    ERIC Educational Resources Information Center

    Parker, Philip D.; Marsh, Herbert W.; Ludtke, Oliver; Trautwein, Ulrich

    2013-01-01

    The internal/external frame of reference and the big-fish-little-pond effect are two major models of academic self-concept formation which have considerable theoretical and empirical support. Integrating the domain specific and compensatory processes of the internal/external frame of reference model with the big-fish-little-pond effect suggests a…

  18. The Reciprocal Internal/External Frame of Reference Model: An Integration of Models of Relations between Academic Achievement and Self-Concept

    ERIC Educational Resources Information Center

    Moller, Jens; Retelsdorf, Jan; Koller, Olaf; Marsh, Herb W.

    2011-01-01

    The reciprocal internal/external frame of reference model (RI/EM) combines the internal/external frame of reference model and the reciprocal effects model. The RI/EM predicts positive effects of mathematics and verbal achievement and academic self-concepts (ASC) on subsequent mathematics and verbal achievements and ASCs within domains and negative…

  19. Development and evaluation of a secondary reference panel for BCR-ABL1 quantification on the International Scale.

    PubMed

    Cross, N C P; White, H E; Ernst, T; Welden, L; Dietz, C; Saglio, G; Mahon, F-X; Wong, C C; Zheng, D; Wong, S; Wang, S-S; Akiki, S; Albano, F; Andrikovics, H; Anwar, J; Balatzenko, G; Bendit, I; Beveridge, J; Boeckx, N; Cerveira, N; Cheng, S-M; Colomer, D; Czurda, S; Daraio, F; Dulucq, S; Eggen, L; El Housni, H; Gerrard, G; Gniot, M; Izzo, B; Jacquin, D; Janssen, J J W M; Jeromin, S; Jurcek, T; Kim, D-W; Machova-Polakova, K; Martinez-Lopez, J; McBean, M; Mesanovic, S; Mitterbauer-Hohendanner, G; Mobtaker, H; Mozziconacci, M-J; Pajič, T; Pallisgaard, N; Panagiotidis, P; Press, R D; Qin, Y-Z; Radich, J; Sacha, T; Touloumenidou, T; Waits, P; Wilkinson, E; Zadro, R; Müller, M C; Hochhaus, A; Branford, S

    2016-09-01

    Molecular monitoring of chronic myeloid leukemia patients using robust BCR-ABL1 tests standardized to the International Scale (IS) is key to proper disease management, especially when treatment cessation is considered. Most laboratories currently use a time-consuming sample exchange process with reference laboratories for IS calibration. A World Health Organization (WHO) BCR-ABL1 reference panel was developed (MR(1)-MR(4)), but access to the material is limited. In this study, we describe the development of the first cell-based secondary reference panel that is traceable to and faithfully replicates the WHO panel, with an additional MR(4.5) level. The secondary panel was calibrated to IS using digital PCR with ABL1, BCR and GUSB as reference genes and evaluated by 44 laboratories worldwide. Interestingly, we found that >40% of BCR-ABL1 assays showed signs of inadequate optimization such as poor linearity and suboptimal PCR efficiency. Nonetheless, when optimized sample inputs were used, >60% demonstrated satisfactory IS accuracy, precision and/or MR(4.5) sensitivity, and 58% obtained IS conversion factors from the secondary reference concordant with their current values. Correlation analysis indicated no significant alterations in %BCR-ABL1 results caused by different assay configurations. More assays achieved good precision and/or sensitivity than IS accuracy, indicating the need for better IS calibration mechanisms. PMID:27109508

  20. Spatial power spectra of the crustal geomagnetic field and core geomagnetic field

    NASA Technical Reports Server (NTRS)

    Mcleod, M. G.; Coleman, P. J., Jr.

    1980-01-01

    Equations providing numerical values of the geomagnetic field spherical harmonic spatial power spectrum as defined by Lowes (1966, 1974) are obtained and this power spectrum is related to various other power spectra. Equations relating the spherical harmonic spatial power spectrum to average great circle power spectra for components of the vector magnetic field in the radial direction, along the great circle track and perpendicular to the first two directions are derived under the assumption that the sources of the field are internal. A statistical model for the crustal and core geomagnetic fields is proposed and used to derive equations for the expected main and crustal spherical harmonic power spectra. The model equations are then compared with observations to determine a scale factor which is then used to obtain an estimate for the core radius and a great circle power spectrum for the field component perpendicular to the great circle and radial directions which are in good agreement with observations. The predicted spherical harmonic power spectrum for the crustal field is found to be consistent with POGO satellite and aircraft data. Other possible models for the crustal and core geomagnetic fields are also briefly considered.

  1. Script Concordance Testing in Continuing Professional Development: Local or International Reference Panels?

    ERIC Educational Resources Information Center

    Pleguezuelos, E. M.; Hornos, E.; Dory, V.; Gagnon, R.; Malagrino, P.; Brailovsky, C. A.; Charlin, B.

    2013-01-01

    Context: The PRACTICUM Institute has developed large-scale international programs of on-line continuing professional development (CPD) based on self-testing and feedback using the Practicum Script Concordance Test© (PSCT). Aims: To examine the psychometric consequences of pooling the responses of panelists from different countries (composite…

  2. The International Federation of Library Associations. A Selected List of References.

    ERIC Educational Resources Information Center

    Cambio, Edward P., Comp.

    Prepared in anticipation of the 40th session of the General Council of the International Federation of Library Associations (IFLA), this bibliography cites materials issued by or under the auspices of the federation and its council, sections, and committees, as well as selected works about IFLA and its various subdivisions. The citations are…

  3. Satellite Vulnerability To Geomagnetic Storms

    NASA Astrophysics Data System (ADS)

    Horne, R. B.; Freemen, M. P.; Riley, D.; Daws, M.; Rutten, K.

    There are several examples where satellites on orbit have failed or partially failed during geomagnetic storms resulting in large insurance claims. Whether the storm is directly responsible for the failures is very controversial, commercially sensitive, and difficult to prove conclusively since there are so few examples. However, there are many non-fatal errors, or anomalies, that occur during the lifetime of spacecraft that enable a statistical analysis. Here we present an analysis of over 5000 satellite anomalies that shows for the first time a statistically significant link between satellite anomalies and geomagnetic storms. We find that the period of highest risk lasts for six days after the start of a magnetic storm. Approximately 40% of anomalies could be due to a random occurrence, but in addition there are between 0 and 35% of satellite anomalies that we attribute as being directly related to geomagnetic storms. We show that the risk depends on satellite prime contractor, orbit type, and age of satellite.

  4. Internal nasal floor configuration in Homo with special reference to the evolution of Neandertal facial form.

    PubMed

    Franciscus, Robert G

    2003-06-01

    The presence of a steeply sloping or depressed nasal floor within the nasal cavity of Neandertals is frequently mentioned as a likely specialization or autapomorphy. The depressed nasal floor has also been seen as contributing to a relatively more capacious nasal cavity in Neandertals, which is tied to cold-climate respiratory adaptation and energetics. These observations have been limited largely to a relatively few intact crania, and the character states associated with this trait have not been as precisely codified or analyzed as those published for Plio-Pleistocene hominins (McCollum et al., 1993, J. Hum. Evol. 24, 87; McCollum, 2000, Am. J. Phys. Anthrop. 112, 275). This study examines the internal nasal floor topography in complete crania and isolated maxillae in European, west Asian, and African fossil Homo (n=158) including 25 Neandertals, and a wide range of recent humans from Europe, the Near East, and Africa (n=522). The configuration of the internal nasal floor relative to the nasal cavity entrance is codified as: 1) level, forming a smooth continuous plane; 2) sloped or mildly stepped; or 3) bilevel with a pronounced vertical depression. The frequency of these nasal floor configurations, and their relationship to both nasal margin cresting patterning and a comprehensive set of nasofacial metrics is examined. Neandertals show a high frequency of the bilevel (depressed) configuration in both adults and subadults (80%), but this configuration is also present in lower frequencies in Middle Pleistocene African, Late Pleistocene non-Neandertal (Skhul, Qafzeh), and European Later Upper Paleolithic samples (15%-50%). The bilevel configuration is also present in lower frequencies (ca. 10%) in all recent human samples, but attains nearly 20% in some sub-Saharan African samples. Across extinct and extant Homo (excluding Neandertals), internal nasal floor configuration is not associated with piriform aperture nasal margin patterning, but the two are strongly

  5. Ready Reference.

    ERIC Educational Resources Information Center

    Koltay, Emery

    1999-01-01

    Includes the following ready reference information: "Publishers' Toll-Free Telephone Numbers"; "How to Obtain an ISBN (International Standard Book Number)"; "How to Obtain an ISSN (International Standard Serial Number)"; and "How to Obtain an SAN (Standard Address Number)". (AEF)

  6. Keith's early work in geomagnetism

    NASA Astrophysics Data System (ADS)

    Lowes, F. J.

    This paper describes how Runcorn was started on his geophysical career by a chance combination of circumstances, when in 1947 he was given the job of measuring the variation of the geomagnetic field with depth inside the Earth, down British coal mines. It then shows how his interest in the semi-conduction of the lower mantle led to attempts to detect DC earth currents, at first again in mines, but later using discarded trans-Pacific telegraph cables. It ends by briefly discussing the “fifth force” measurements he instigated, which, though not a geomagnetic problem, had many similarities with the original mine experiments.

  7. Survey Data for Geomagnetic Field Modelling

    NASA Technical Reports Server (NTRS)

    Barraclough, D. R.; Macmillan, S.

    1992-01-01

    The survey data discussed here are based on observations made relatively recently at points on land. A special subset of land survey data consists of those made at specially designated sites known as repeat stations. This class of data will be discussed in another part of this document (Barton, 1991b), so only the briefest of references will be made to repeat stations here. This discussion of 'ordinary' land survey data begins with a description of the spatial and temporal distributions of available survey data based on observations made since 1900. (The reason for this rather arbitrary choice of cut-off date is that this was the value used in the production of the computer file of magnetic survey data (land, sea, air, satellite, rocket) that is the primary source of data for geomagnetic main-field modeling). This is followed by a description of the various types of error to which these survey data are, or may be, subject and a discussion of the likely effects of such errors on field models produced from the data. Finally, there is a short section on the availability of geomagnetic survey data, which also describes how the data files are maintained.

  8. On Geomagnetism and Paleomagnetism

    NASA Technical Reports Server (NTRS)

    Voorhies, Coerte V.

    1998-01-01

    A statistical description of Earth's broad scale, core-source magnetic field has been developed and tested. The description features an expected, or mean, spatial magnetic power spectrum that is neither "flat" nor "while" at any depth, but is akin to spectra advanced by Stevenson and McLeod. This multipole spectrum describes the magnetic energy range; it is not steep enough for Gubbins' magnetic dissipation range. Natural variations of core multipole powers about their mean values are to be expected over geologic time and are described via trial probability distribution functions that neither require nor prohibit magnetic isotropy. The description is thus applicable to core-source dipole and low degree non-dipole fields despite axial dipole anisotropy. The description is combined with main field models of modem satellite and surface geomagnetic measurements to make testable predictions of: (1) the radius of Earth's core, (2) mean paleomagnetic field intensity, and (3) the mean rates and durations of both dipole power excursions and durable axial dipole reversals. The predicted core radius is 0.7% above the 3480 km seismologic value. The predicted root mean square paleointensity (35.6 mu T) and mean Virtual Axial Dipole Moment (about 6.2 lx 1022 Am(exp 2)) are within the range of various mean paleointensity estimates. The predicted mean rate of dipole power excursions, as defined by an absolute dipole moment <20% of the 1980 value, is 9.04/Myr and 14% less than obtained by analysis of a 4 Myr paleointensity record. The predicted mean rate of durable axial dipole reversals (2.26/Myr) is 2.3% more than established by the polarity time-scale for the past 84 Myr. The predicted mean duration of axial dipole reversals (5533 yr) is indistinguishable from an observational value. The accuracy of these predictions demonstrates the power and utility of the description, which is thought to merit further development and testing. It is suggested that strong stable stratification

  9. First results from the first Croatian geomagnetic observatory

    NASA Astrophysics Data System (ADS)

    Mandic, Igor; Herak, Davorka; Heilig, Balazs

    2013-04-01

    The first Croatian geomagnetic observatory was established in the area of the Nature Park Lonjsko Polje, after a century of sporadic efforts originating from the proposals of Andrija Mohorovicic. The location was chosen after exhaustive surveys of possible sites. It is located far enough from sources of civilization noise, and was found to be an area without magnetic anomalies and with a low field gradient. The construction of the observatory buildings was completed in the autumn of 2011. The furnishing and installation of instruments and test measurements were completed by the beginning of summer 2012, ever since we have continuous recordings of the geomagnetic elements. In the beginning of December 2012 the fluxgate magnetometer LEMI-035 (H,D,Z orientation) has been installed under the framework of the PLASMON project in cooperation with the Tihany Observatory (Hungary). Permanent data of high quality from our observatory will contribute to the monitoring of the Earth's magnetic field on the regional and global levels, thus enabling further development of geomagnetism in Croatia through collaboration with scientists from the other countries, participation in the international projects, eventual membership in the International Real-time Magnetic Observatory Network (INTERMAGNET), etc. The field elements for the epoch 2012,75 and the baselines are presented together with highlights of some recorded geomagnetic events so far. Furthermore, the comparison between the variation data recorded by the dIdD and the fluxgate LEMI-035 magnetometer is presented.

  10. Estimating the change in asymptotic direction due to secular changes in the geomagnetic field

    NASA Technical Reports Server (NTRS)

    Flueckiger, E. O.; Smart, D. F.; Shea, M. A.; Gentile, L. C.; Bathurat, A. A.

    1985-01-01

    The concept of geomagnetic optics, as described by the asymptotic directions of approach, is extremely useful in the analysis of cosmic radiation data. However, when changes in cutoff occur as a result of evolution in the geomagnetic field, there are corresponding changes in the asymptotic cones of acceptance. A method is introduced of estimating the change in the asymptotic direction of approach for vertically incident cosmic ray particles from a reference set of directions at a specific epoch by considering the change in the geomagnetic cutoff.

  11. Geomagnetic inverse problem and data assimilation: a progress report

    NASA Astrophysics Data System (ADS)

    Aubert, Julien; Fournier, Alexandre

    2013-04-01

    In this presentation I will present two studies recently undertaken by our group in an effort to bring the benefits of data assimilation to the study of Earth's magnetic field and the dynamics of its liquid iron core, where the geodynamo operates. In a first part I will focus on the geomagnetic inverse problem, which attempts to recover the fluid flow in the core from the temporal variation of the magnetic field (known as the secular variation). Geomagnetic data can be downward continued from the surface of the Earth down to the core-mantle boundary, but not further below, since the core is an electrical conductor. Historically, solutions to the geomagnetic inverse problem in such a sparsely observed system were thus found only for flow immediately below the core mantle boundary. We have recently shown that combining a numerical model of the geodynamo together with magnetic observations, through the use of Kalman filtering, now allows to present solutions for flow throughout the core. In a second part, I will present synthetic tests of sequential geomagnetic data assimilation aiming at evaluating the range at which the future of the geodynamo can be predicted, and our corresponding prospects to refine the current geomagnetic predictions. Fournier, Aubert, Thébault: Inference on core surface flow from observations and 3-D dynamo modelling, Geophys. J. Int. 186, 118-136, 2011, doi: 10.1111/j.1365-246X.2011.05037.x Aubert, Fournier: Inferring internal properties of Earth's core dynamics and their evolution from surface observations and a numerical geodynamo model, Nonlinear Proc. Geoph. 18, 657-674, 2011, doi:10.5194/npg-18-657-2011 Aubert: Flow throughout the Earth's core inverted from geomagnetic observations and numerical dynamo models, Geophys. J. Int., 2012, doi: 10.1093/gji/ggs051

  12. Use of Myometrium as an Internal Reference for Endometrial and Cervical Cancer on Multiphase Contrast-Enhanced MRI

    PubMed Central

    Lin, Chia-Ni; Liao, Yu-San; Chen, Wen-Chang; Wang, Yue-Sheng; Lee, Li-Wen

    2016-01-01

    Background Myometrial smooth muscle is normally within the field of view for the gynecological imaging. This study aimed to investigate the use of normal myometrium as an internal reference for endometrial and cervical cancer during multiphase contrast-enhanced magnetic resonance imaging (MCE-MRI) and to explore whether this information regarding tumor enhancement relative to the myometrium could be used to discriminate between endometrial and cervical cancer. Methods MRI images, before and after contrast enhancement, were analyzed in newly diagnosed cervical (n = 18) and endometrial cancer (n = 19) patients. Signal intensities (SIs) from tumor tissue and non-neoplastic myometrium were measured using imaging software. Results The relative signal for cervical cancer was approximately 30% higher than that of endometrial cancer after contrast administration. The area under receiver operating characteristic curve for SI, relative signal enhancement, and tumor to myometrium contrast ratio (as used to discriminate between cervical cancer and endometrial cancer) was 0.7807, 0.7456 and 0.7895, respectively. There was no difference in SI of the normal myometrium between endometrial and cervical cancer patients prior to and after contrast administration. Using non-tumorous myometrium as an internal reference, the tumor to myometrium contrast ratio was significantly higher in tumor tissue from cervical cancer compared with that from endometrial cancer at 25 s post contrast enhancement (p = 0.0016), with an optimal sensitivity of 72.22% and specificity of 84.21%. Conclusion With SI normalized to baseline or normal myometrium, tumor tissue from cervical cancer patients showed significant hyperintensity compared with that of tumor tissue from endometrial cancer patients after contrast enhancement, yielding acceptable performance. The use of the myometrium as an internal reference may provide an alternative method to analyze MCE-MRI data. PMID:27326456

  13. Mantle superplumes induce geomagnetic superchrons

    NASA Astrophysics Data System (ADS)

    Olson, Peter; Amit, Hagay

    2015-07-01

    We use polarity reversal systematics from numerical dynamos to quantify the hypothesis that the modulation of geomagnetic reversal frequency, including geomagnetic superchrons, results from changes in core heat flux related to growth and collapse of lower mantle superplumes. We parameterize the reversal frequency sensitivity from numerical dynamos in terms of average core heat flux normalized by the difference between the present-day core heat flux and the core heat flux at geomagnetic superchron onset. A low-order polynomial fit to the 0-300 Ma Geomagnetic Polarity Time Scale (GPTS) reveals that a decrease in core heat flux relative to present-day of approximately 30% can account for the Cretaceous Normal Polarity and Kiaman Reverse Polarity Superchrons, whereas the hyper-reversing periods in the Jurassic require a core heat flux equal to or higher than present-day. Possible links between GPTS transitions, large igneous provinces (LIPs), and the two lower mantle superplumes are explored. Lower mantle superplume growth and collapse induce GPTS transitions by increasing and decreasing core heat flux, respectively. Age clusters of major LIPs postdate transitions from hyper-reversing to superchron geodynamo states by 30-60 Myr, suggesting that superchron onset may be contemporaneous with LIP-forming instabilities produced during collapses of lower mantle superplumes.

  14. Climate determinism or Geomagnetic determinism?

    NASA Astrophysics Data System (ADS)

    Gallet, Y.; Genevey, A.; Le Goff, M.; Fluteau, F.; Courtillot, V.

    2006-12-01

    A number of episodes of sharp geomagnetic field variations (in both intensity and direction), lasting on the order of a century, have been identified in archeomagnetic records from Western Eurasia and have been called "archeomagnetic jerks". These seem to correlate well with multi-decadal cooling episodes detected in the North Atlantic Ocean and Western Europe, suggesting a causal link between both phenomena. A possible mechanism could be a geomagnetic modulation of the cosmic ray flux that would control the nucleation rate of clouds. We wish to underline the remarkable coincidence between archeomagnetic jerks, cooling events in Western Europe and drought periods in tropical and sub-tropical regions of the northern hemisphere. The latter two can be interpreted in terms of global teleconnections among regional climates. It has been suggested that these climatic variations had caused major changes in the history of ancient civilizations, such as in Mesopotamia, which were critically dependent on water supply and particularly vulnerable to lower rainfall amounts. This is one of the foundations of "climate determinism". Our studies, which suggest a geomagnetic origin for at least some of the inferred climatic events, lead us to propose the idea of a "geomagnetic determinism" in the history of humanity.

  15. Klimovskaya: A new geomagnetic observatory

    NASA Astrophysics Data System (ADS)

    Soloviev, A. A.; Sidorov, R. V.; Krasnoperov, R. I.; Grudnev, A. A.; Khokhlov, A. V.

    2016-05-01

    In 2011 Geophysical Center RAS (GC RAS) began to deploy the Klimovskaya geomagnetic observatory in the south of Arkhangelsk region on the territory of the Institute of Physiology of Natural Adaptations, Ural Branch, Russian Academy of Sciences (IPNA UB RAS). The construction works followed the complex of preparatory measures taken in order to confirm that the observatory can be constructed on this territory and to select the optimal configuration of observatory structures. The observatory equipping stages are described in detail, the technological and design solutions are described, and the first results of the registered data quality control are presented. It has been concluded that Klimovskaya observatory can be included in INTERMAGNET network. The observatory can be used to monitor and estimate geomagnetic activity, because it is located at high latitudes and provides data in a timely manner to the scientific community via the web-site of the Russian-Ukrainian Geomagnetic Data Center. The role of ground observatories such as Klimovskaya remains critical for long-term observations of secular variation and for complex monitoring of the geomagnetic field in combination with low-orbiting satellite data.

  16. CSNI Project for Fracture Analyses of Large-Scale International Reference Experiments (FALSIRE II)

    SciTech Connect

    Bass, B.R.; Pugh, C.E.; Keeney, J.; Schulz, H.; Sievers, J.

    1996-11-01

    A summary of Phase II of the Project for FALSIRE is presented. FALSIRE was created by the Fracture Assessment Group (FAG) of the OECD/NEA`s Committee on the Safety of Nuclear Installations (CNSI) Principal Working Group No. 3. FALSIRE I in 1988 assessed fracture methods through interpretive analyses of 6 large-scale fracture experiments in reactor pressure vessel (RPV) steels under pressurized- thermal-shock (PTS) loading. In FALSIRE II, experiments examined cleavage fracture in RPV steels for a wide range of materials, crack geometries, and constraint and loading conditions. The cracks were relatively shallow, in the transition temperature region. Included were cracks showing either unstable extension or two stages of extensions under transient thermal and mechanical loads. Crack initiation was also investigated in connection with clad surfaces and with biaxial load. Within FALSIRE II, comparative assessments were performed for 7 reference fracture experiments based on 45 analyses received from 22 organizations representing 12 countries. Temperature distributions in thermal shock loaded samples were approximated with high accuracy and small scatter bands. Structural response was predicted reasonably well; discrepancies could usually be traced to the assumed material models and approximated material properties. Almost all participants elected to use the finite element method.

  17. International collaborative study of the endogenous reference gene LAT52 used for qualitative and quantitative analyses of genetically modified tomato.

    PubMed

    Yang, Litao; Zhang, Haibo; Guo, Jinchao; Pan, Liangwen; Zhang, Dabing

    2008-05-28

    One tomato ( Lycopersicon esculentum) gene, LAT52, has been proved to be a suitable endogenous reference gene for genetically modified (GM) tomato detection in a previous study. Herein are reported the results of a collaborative ring trial for international validation of the LAT52 gene as endogenous reference gene and its analytical systems; 14 GMO detection laboratories from 8 countries were invited, and results were finally received from 13. These data confirmed the species specificity by testing 10 plant genomic DNAs, less allelic variation and stable single copy number of the LAT52 gene, among 12 different tomato cultivars. Furthermore, the limit of detection of LAT52 qualitative PCR was proved to be 0.1%, which corresponded to 11 copies of haploid tomato genomic DNA, and the limit of quantification for the quantitative PCR system was about 10 copies of haploid tomato genomic DNA with acceptable PCR efficiency and linearity. Additionally, the bias between the test and true values of 8 blind samples ranged from 1.94 to 10.64%. All of these validated results indicated that the LAT52 gene is suitable for use as an endogenous reference gene for the identification and quantification of GM tomato and its derivates. PMID:18442244

  18. A decrease in solar and geomagnetic activity from cycle 19 to cycle 24

    NASA Astrophysics Data System (ADS)

    Gvishiani, A. D.; Starostenko, V. I.; Sumaruk, Yu. P.; Soloviev, A. A.; Legostaeva, O. V.

    2015-05-01

    Variations in the solar and geomagnetic activity from cycle 19 to cycle 24 were considered based on data from the magnetic observatories of the Russian-Ukrainian INTERMAGNET segment and international centers of data on solar-terrestrial physics. It has been indicated that activity decreases over the course of time. This is especially evident during the cycle 24 growth phase. The possible causes and consequences of a decrease in geomagnetic activity were analyzed.

  19. The risk characteristics of solar and geomagnetic activity

    NASA Astrophysics Data System (ADS)

    Podolska, Katerina

    2016-04-01

    The main aim of this contribution is a deeper analysis of the influence of solar activity which is expected to have an impact on human health, and therefore on mortality, in particular civilization and degenerative diseases. We have constructed the characteristics that represent the risk of solar and geomagnetic activity on human health on the basis of our previous analysis of association between the daily numbers of death on diseases of the nervous system and diseases of the circulatory system and solar and geomagnetic activity in the Czech Republic during the years 1994 - 2013. We used long period daily time series of numbers of deaths by cause, long period time series of solar activity indices (namely R and F10.7), geomagnetic indicies (Kp planetary index, Dst) and ionospheric parameters (foF2 and TEC). The ionospheric parameters were related to the geographic location of the Czech Republic and adjusted for middle geographic latitudes. The risk characteristics were composed by cluster analysis in time series according to the phases of the solar cycle resp. the seasonal insolation at mid-latitudes or the daily period according to the impact of solar and geomagnetic activity on mortality by cause of death from medical cause groups of death VI. Diseases of the nervous system and IX. Diseases of the circulatory system mortality by 10th Revision of International Classification of Diseases WHO (ICD-10).

  20. Interplanetary field and plasma during initial phase of geomagnetic storms

    NASA Technical Reports Server (NTRS)

    Patel, V. L.; Wiskerchen, M. J.

    1975-01-01

    Twenty-three geomagnetic storm events during 1966 to 1970 were studied by using simultaneous interplanetary magnetic field and plasma parameters. Explorer 33 and 35 field and plasma data were analyzed on large-scale (hourly) and small-scale (3 min.) during the time interval coincident with the initial phase of the geomagnetic storms. The solar-ecliptic Bz component turns southward at the end of the initial phase, thus triggering the main phase decrease in Dst geomagnetic field. The By component also shows large fluctuations along with Bz. When there are no clear changes in the Bz component, the By shows abrupt changes at the main phase onset. On the small-scale, behavior of the magnetic field and electric field were studied in detail for the three events; it is found that the field fluctuations in By, Bz and Ey and Ez are present in the initial phase. In the large-scale, the behavior field remains quiet because the small-scale variations are averaged out. It appears that large as well as small time scale fluctuations in the interplanetary field and plasma help to alter the internal electromagnetic state of the magnetosphere so that a ring current could causing a geomagnetic storm decrease.

  1. Addressing Issues in the Development and Use of the Composite International Reference Values as Rorschach Norms for Adults.

    PubMed

    Meyer, Gregory J; Shaffer, Thomas W; Erdberg, Philip; Horn, Sandra L

    2015-01-01

    This article describes 3 studies evaluating normative reference data for the Rorschach Comprehensive System (CS; Exner, 2003, 2007), with a particular focus on the viability of the Composite International Reference Values (CIRVs) that were compiled from 21 adult studies by Meyer, Erdberg, and Shaffer (2007). Study 1 documented how the CIRV norms are virtually identical when organized into 3 groups differentiated by the quality of their data collection effort, including an optimal group of 4 samples that relied on multiple experienced examiners and provided ongoing quality control over administration and coding. Analyses also showed that relative to the group of more optimal samples, the group of less optimal samples did not produce more variability in summary scores within or across samples or lower interrater reliability for coding. Study 2 used the existing CS reference norms to generate T scores for the CIRV means and documented how the CS norms make other samples of healthy nonpatients look psychologically impaired in multiple domains. Study 3 documented with examples from 4 different countries how 2 sets of within-country local norms produced notably different results on some variables, which compromises the ability of local norms to be used instead of the CIRVs. Taken together, the 3 studies provide support for the use of CIRVs in clinical practice as norms that are generalizable across samples, settings, languages, and cultures and that account for the natural variability that is present when clinicians and researchers contend with the ambiguity contained in the standard CS reference materials concerning the proper ways to administer and code. We conclude by urging CS users to rely on the CIRVs when making clinical inferences and to adopt alternative methods of ensuring they are following cohesively standardized administration and coding guidelines. PMID:25297806

  2. Extreme Geomagnetic Storms - 1868 - 2010

    NASA Astrophysics Data System (ADS)

    Vennerstrom, S.; Lefevre, L.; Dumbović, M.; Crosby, N.; Malandraki, O.; Patsou, I.; Clette, F.; Veronig, A.; Vršnak, B.; Leer, K.; Moretto, T.

    2016-05-01

    We present the first large statistical study of extreme geomagnetic storms based on historical data from the time period 1868 - 2010. This article is the first of two companion papers. Here we describe how the storms were selected and focus on their near-Earth characteristics. The second article presents our investigation of the corresponding solar events and their characteristics. The storms were selected based on their intensity in the aa index, which constitutes the longest existing continuous series of geomagnetic activity. They are analyzed statistically in the context of more well-known geomagnetic indices, such as the Kp and Dcx/Dst index. This reveals that neither Kp nor Dcx/Dst provide a comprehensive geomagnetic measure of the extreme storms. We rank the storms by including long series of single magnetic observatory data. The top storms on the rank list are the New York Railroad storm occurring in May 1921 and the Quebec storm from March 1989. We identify key characteristics of the storms by combining several different available data sources, lists of storm sudden commencements (SSCs) signifying occurrence of interplanetary shocks, solar wind in-situ measurements, neutron monitor data, and associated identifications of Forbush decreases as well as satellite measurements of energetic proton fluxes in the near-Earth space environment. From this we find, among other results, that the extreme storms are very strongly correlated with the occurrence of interplanetary shocks (91 - 100 %), Forbush decreases (100 %), and energetic solar proton events (70 %). A quantitative comparison of these associations relative to less intense storms is also presented. Most notably, we find that most often the extreme storms are characterized by a complexity that is associated with multiple, often interacting, solar wind disturbances and that they frequently occur when the geomagnetic activity is already elevated. We also investigate the semiannual variation in storm occurrence

  3. Social Justice and Third World Education. Reference Books in International Education, Volume 37. Garland Reference Library of Social Science, Volume 1130.

    ERIC Educational Resources Information Center

    Scrase, Timothy J., Ed.

    The impact of international social change is having a marked effect on developing nations' internal policies, budgets, and development programs. This collection of articles addresses the importance of education in the creation of social policies and development policies; the effect of international changes on education; the investment of limited…

  4. Predicting geomagnetic reversals via data assimilation: a feasibility study

    NASA Astrophysics Data System (ADS)

    Morzfeld, Matthias; Fournier, Alexandre; Hulot, Gauthier

    2014-05-01

    The system of three ordinary differential equations (ODE) presented by Gissinger in [1] was shown to exhibit chaotic reversals whose statistics compared well with those from the paleomagnetic record. We explore the geophysical relevance of this low-dimensional model via data assimilation, i.e. we update the solution of the ODE with information from data of the dipole variable. The data set we use is 'SINT' (Valet et al. [2]), and it provides the signed virtual axial dipole moment over the past 2 millions years. We can obtain an accurate reconstruction of these dipole data using implicit sampling (a fully nonlinear Monte Carlo sampling strategy) and assimilating 5 kyr of data per sweep. We confirm our calibration of the model using the PADM2M dipole data set of Ziegler et al. [3]. The Monte Carlo sampling strategy provides us with quantitative information about the uncertainty of our estimates, and -in principal- we can use this information for making (robust) predictions under uncertainty. We perform synthetic data experiments to explore the predictive capability of the ODE model updated by data assimilation. For each experiment, we produce 2 Myr of synthetic data (with error levels similar to the ones found in the SINT data), calibrate the model to this record, and then check if this calibrated model can reliably predict a reversal within the next 5 kyr. By performing a large number of such experiments, we can estimate the statistics that describe how reliably our calibrated model can predict a reversal of the geomagnetic field. It is found that the 1 kyr-ahead predictions of reversals produced by the model appear to be accurate and reliable. These encouraging results prompted us to also test predictions of the five reversals of the SINT (and PADM2M) data set, using a similarly calibrated model. Results will be presented and discussed. References Gissinger, C., 2012, A new deterministic model for chaotic reversals, European Physical Journal B, 85:137 Valet, J

  5. Geomagnetic Field Reversals and Life on the Earth in Phanerozoic Time

    NASA Astrophysics Data System (ADS)

    Pechersky, D. M.

    2014-10-01

    Global paleomagnetic and biostratigraphic data are generalized. As a result it is found out that the direct connection between geomagnetic reversals, biozones and maxima of mass extinction of a biota is absent. At the same time it is noted close to a synchronous total picture of consistent changes of biozones and geomagnetic polarity. It is explained by the general source - the Earth's diurnal rotation. The reversal polarity of a geomagnetic field prevailed during the Phanerozoic that is agreed with the Earth's counterclockwise rotation. Change of polarity of a field, most likely, is connected with acceleration or deceleration of rotation speed of the internal core relative to the Earth's mantle. Lack of direct interrelation between changes in the biosphere and geomagnetic field indicate a lack of influence of a field on life evolution on Earth. It follows also from the fact that life on Earth developed from primitive unicellular forms to mammals and the man and diversity of biota was grew against a close condition of a geomagnetic field during ~2,5 billion years and irrespective of numerous geomagnetic reversals. Main conclusion: evolutionary development of life on Earth doesn't depend both on large changes of a geomagnetic field, and on the extreme catastrophic events conducting to mass extinction of a biota.

  6. Methods of approximation of reference fields of different classes

    NASA Astrophysics Data System (ADS)

    Kolesova, Valentina I.

    1993-11-01

    The summary geomagnetic field on the reference field for the regional anomalies is surface of the Earth consists of the follow- the sum of the main geomagnetic field and ing components: the intermediate anomalies. Since the components mentioned above have the F0 = Fm + Fim + Fr + F1 + F (1) different space-spectral characteristics, different methods are used for the analytiwhere cal descriptions. The main geomagnetic field, being the global reference field, is approximated by F0 - the observed geomagnetic field the optimal way as a spherical harmonic Fm - the main geomagnetic field series [1]: Fim - the field of the intermediate anoma- n lies Fr - the field of the regional anomalies X = (g cosm\\ + n=i m=O F1 - the field of the local anomalies, - the external geomagnetic field.

  7. Types and Characteristics of Data for Geomagnetic Field Modeling

    NASA Technical Reports Server (NTRS)

    Langel, R. A. (Editor); Baldwin, R. T. (Editor)

    1992-01-01

    Given here is material submitted at a symposium convened on Friday, August 23, 1991, at the General Assembly of the International Union of Geodesy and Geophysics (IUGG) held in Vienna, Austria. Models of the geomagnetic field are only as good as the data upon which they are based, and depend upon correct understanding of data characteristics such as accuracy, correlations, systematic errors, and general statistical properties. This symposium was intended to expose and illuminate these data characteristics.

  8. International Linear Collider Reference Design Report Volume 2: Physics at the ILC

    SciTech Connect

    Aarons, Gerald; Abe, Toshinori; Abernathy, Jason; Ablikim, Medina; Abramowicz, Halina; Adey, David; Adloff, Catherine; Adolphsen, Chris; Afanaciev, Konstantin; Agapov, Ilya; Ahn, Jung-Keun; Aihara, Hiroaki; Akemoto, Mitsuo; del Carmen Alabau, Maria; Albert, Justin; Albrecht, Hartwig; Albrecht, Michael; Alesini, David; Alexander, Gideon; Alexander, Jim; Allison, Wade; /SLAC /Tokyo U. /Victoria U. /Beijing, Inst. High Energy Phys. /Tel Aviv U. /Birmingham U. /Annecy, LAPP /Minsk, High Energy Phys. Ctr. /DESY /Royal Holloway, U. of London /CERN /Pusan Natl. U. /KEK, Tsukuba /Orsay, LAL /Notre Dame U. /Frascati /Cornell U., Phys. Dept. /Oxford U. /Hefei, CUST /Bangalore, Indian Inst. Sci. /Fermilab

    2011-11-14

    The triumph of 20th century particle physics was the development of the Standard Model and the confirmation of many of its aspects. Experiments determined the particle constituents of ordinary matter, and identified four forces that hold matter together and transform it from one form to another. Particle interactions were found to obey precise laws of relativity and quantum theory. Remarkable features of quantum physics were observed, including the real effects of 'virtual' particles on the visible world. Building on this success, particle physicists are now able to address questions that are even more fundamental, and explore some of the deepest mysteries in science. The scope of these questions is illustrated by this summary from the report Quantum Universe: (1) Are there undiscovered principles of nature; (2) How can we solve the mystery of dark energy; (3) Are there extra dimensions of space; (4) Do all the forces become one; (5) Why are there so many particles; (6) What is dark matter? How can we make it in the laboratory; (7) What are neutrinos telling us; (8) How did the universe begin; and (9) What happened to the antimatter? A worldwide program of particle physics investigations, using multiple approaches, is already underway to explore this compelling scientific landscape. As emphasized in many scientific studies, the International Linear Collider is expected to play a central role in what is likely to be an era of revolutionary advances. Discoveries from the ILC could have breakthrough impact on many of these fundamental questions. Many of the scientific opportunities for the ILC involve the Higgs particle and related new phenomena at Terascale energies. The Standard Model boldly hypothesizes a new form of Terascale energy, called the Higgs field, that permeates the entire universe. Elementary particles acquire mass by interacting with this field. The Higgs field also breaks a fundamental electroweak force into two forces, the electromagnetic and weak

  9. Teaching Geomagnetism in High School

    NASA Astrophysics Data System (ADS)

    Stern, D. P.

    2001-05-01

    Many high school curricula include a one-year course in Earth Sciences, often in the 9th grade (essentially pre-algebra). That is a good time to teach about geomagnetism. Not only are dipole reversals and sea-floor magnetization central to this subject, but this is a good opportunity to introduce students to magnetism and its connection to electric currents. The story of Oersted and Faraday give a fascinating insight into the uneven path of scientific discovery, the magnetic compass and William Gilbert provide a view of the beginnings of the scientific revolution, and even basic concepts of dynamo theory and its connection to solar physics can be included. A resource including all the suitable material now exists on the world-wide web at http://www-spof.gsfc.nasa.gov/earthmag/demagint.htm (home page). A 1-month unit on geomagnetism will be outlined.

  10. Ice ages and geomagnetic reversals

    NASA Technical Reports Server (NTRS)

    Wu, Patrick

    1992-01-01

    There have been speculations on the relationship between climatic cooling and polarity reversals of the earth's magnetic field during the Pleistocene. Two of the common criticisms on this relationship have been the reality of these short duration geomagnetic events and the accuracy of their dates. Champion et al. (1988) have reviewed recent progress in this area. They identified a total of 10 short-duration polarity events in the last 1 Ma and 6 of these events have been found in volcanic rocks, which also have K-Ar dates. Supposing that the speculated relationship between climatic cooling and geomagnetic reversals actually exist, two mechanisms that assume climatic cooling causes short period magnetic reversals will be investigated. These two methods are core-mantle boundary topography and transfer of the rotational energy to the core.

  11. Finnish geomagnetically induced currents project

    SciTech Connect

    Vilianen, A.; Pirjola, R. . Dept. of Geophysics)

    1995-01-01

    This article is a summary of Results of the Finnish Project on Geomagnetically Induced Currents,'' published in Surveys in Geophysics 15:383-408, Kluwer Academic Publishers, Netherlands, 1994. IVO and FMI carried out a 1-year GIC project from June 1991 to May 1992. The time of the project was a little after the sunspot maximum, and the geomagnetic activity was high; there were 34 major or severe magnetic storm days (A[sub k] index at least 50). The main aim was to derive reliable statistics of the occurrences of GICs at different sites of the Finnish 400 and 220 kV power systems. Besides the practical engineering purpose, the project is also geophysically relevant by providing a GIC data set usable for large-scale investigations of auroral ionospheric-magnetospheric processes and of the earth's structure.

  12. Geomagnetic excursions and climate change

    NASA Technical Reports Server (NTRS)

    Rampino, M. R.

    1983-01-01

    Rampino argues that although Kent (1982) demonstrated that the intensity of natural remanent magnetism (NRM) in deep-sea sediments is sensitive to changes in sediment type, and hence is not an accurate indicator of the true strength of the geomagnetic field, it does not offer an alternative explanation for the proposed connections between excursions, climate, and orbital parameters. Kent replies by illustrating some of the problems associated with geomagnetic excursions by considering the record of proposed excursions in a single critical core. The large departure from an axial dipole field direction seen in a part of the sample is probably due to a distorted record; the drawing and storage of the sample, which is described, could easily have led to disturbance and distortion of the record.

  13. Forecasts of geomagnetic secular variation

    NASA Astrophysics Data System (ADS)

    Wardinski, Ingo

    2014-05-01

    We attempt to forecast the geomagnetic secular variation based on stochastic models, non-parametric regression and singular spectrum analysis of the observed past field changes. Although this modelling approach is meant to be phenomenological, it may provide some insight into the mechanisms underlying typical time scales of geomagnetic field changes. We follow two strategies to forecast secular variation: Firstly, by applying time series models, and secondly, by using time-dependent kinematic models of the advected secular variation. These forecasts can span decades, to longer periods. This depends on the length of the past observations used as input, with different input models leading to different details in the forecasts. These forecasts become more uncertain over longer forecasting periods. One appealing reason is the disregard of magnetic diffusion in the kinematic modelling. But also the interactions of unobservable small scale core field with core flow at all scale unsettle the kinematic forecasting scheme. A further (obvious) reason is that geomagnetic secular variation can not be mimicked by linear time series models as the dynamo action itself is highly non-linear. Whether the dynamo action can be represented by a simple low-dimensional system requires further analysis.

  14. Future of geomagnetism and paleomagnetism

    NASA Astrophysics Data System (ADS)

    Banerjee, S. K.; Cain, J. C.; Van der Voo, R.

    After the heady days of the 1960s, when geomagnetism and paleomagnetism provided crucial quantitative evidence for plate tectonics by establishing the geomagnetic polarity timescale, the 1980s may appear to be somewhat tame in the eyes of an average geophysicist. To such a person, the intervening 1970s may well look like a period of “mopping up” after the big event has happened, and it may not be unfair for him or her to ask what significant discoveries in geomagnetism and paleomagnetism (GP) have been made since 1970. The practitioners in this field of research are individuals who carry out their work without a large degree of formal overlap, so it is not surprising that the same question about recent accomplishments has arisen also in the minds of AGU GP Section members. This question came to the forefront especially during the 1984 AGU Fall Meeting, when members spoke strongly (in private conversations) about a perceived decrease in National Science Foundation funding of GP-related research projects.

  15. Correlative comparison of geomagnetic storms and auroral substorms using geomagnetic indeces. Master's thesis

    SciTech Connect

    Cade, W.B.

    1993-06-01

    Partial contents include the following: (1) Geomagnetic storm and substorm processes; (2) Magnetospheric structure; (3) Substorm processes; (4) Data description; (5) Geomagnetic indices; and (6) Data period and data sets.

  16. The high latitudes in the International Reference Ionosphere; Meeting C4 of Commission C, COSPAR Scientific Assembly, 30th, Hamburg, Germany, July 11-21, 1994

    NASA Technical Reports Server (NTRS)

    Rawer, K.; Bilitza, D.; Singer, W.

    1995-01-01

    An international conference on high-latitude ionospheric modeling produced 27 papers in the areas of ionospheric mapping, electron density and distribution, ion density and distribution, ionospheric storems, ionospheric composition, and ionospheric sounding techniques. Upgrades to the International Reference Ionosphere (IRI) model were proposed in several papers.

  17. The Geomagnetic Field During a Reversal

    NASA Technical Reports Server (NTRS)

    Heirtzler, James R.

    2003-01-01

    By modifying the IGRF it is possible to learn what may happen to the geomagnetic field during a geomagnetic reversal. If the entire IGRF reverses then the declination and inclination only reverse when the field strength is zero. If only the dipole component of the IGRF reverses a large geomagnetic field remains when the dipole component is zero and he direction of the field at the end of the reversal is not exactly reversed from the directions at the beginning of the reversal.

  18. TOPLA: A New Empirical Representation of the F-Region Topside and Plasmasphere for the International Reference Ionosphere

    NASA Technical Reports Server (NTRS)

    Bilitza, D.; Reinisch, B.; Gallagher, D.; Huang, X.; Truhlik, V.; Nsumei, P.

    2007-01-01

    The goal of this LWS tools effort is the development of a new data-based F-region TOpside and PLAsmasphere (TOPLA) model for the electron density (Ne) and temperature (Te) for inclusion in the International Reference Ionosphere (IRI) model using newly available satellite data and models for these regions. The IRI model is the de facto international standard for specification of ionospheric parameters and is currently being considered as an ISO Technical Specification for the ionosphere. Our effort is directed towards improving the topside part of the model and extending it into the plasmasphere. Specifically we are planning to overcome the following shortcomings of the current IRI topside model: (I) overestimation of densities above 700 km by a factor of 2 and more, (3) unrealistically steep density profiles at high latitudes during very high solar activities, (4) no solar cycle variations and no semi-annual variations for the electron temperature, (5) discontinuities or unphysical gradients when merging with plasmaspheric models. We will report on first accomplishments and on the current status of the project.

  19. Possible relationship between the Earth's rotation variations and geomagnetic field reversals over the past 510 Myr

    NASA Astrophysics Data System (ADS)

    Pacca, Igor; Frigo, Everton; Hartmann, Gelvam

    2015-04-01

    The Earth’s rotation can change as a result of several internal and external processes, each of which is at a different timescale. Here, we present some possible connections between the Earth’s rotation variations and the geomagnetic reversal frequency rates over the past 120 Myr. In addition, we show the possible relationship between the geomagnetic field reversal frequency and the δ18O oscillations. Because the latter reflects the glacial and interglacial periods, we hypothesize that it can be used as a possible indicator to explain the length of day (LOD) variations and consequently the reversal field frequency over the past 510 Myr. Therefore, our analysis suggests that the relationships between the geomagnetic reversal frequency rates and the Earth’s rotation changes during the Phanerozoic. However, more reversal data are required for periods before the KRS to strengthen the perspective of using the geomagnetic reversal data as a marker for the LOD variations through geological times.

  20. ASSIST internals reference manual

    NASA Technical Reports Server (NTRS)

    Johnson, Sally C.; Boerschlein, David P.

    1994-01-01

    The Abstract Semi-Markov Specification Interface to the SURE Tool (ASSIST) program was developed at NASA LaRC in order to analyze the reliability of virtually any fault-tolerant system. A user manual was developed to detail its use. Certain technical specifics are of no concern to the end user, yet are of importance to those who must maintain and/or verify the correctness of the tool. This document takes a detailed look into these technical issues.

  1. The Causes of Geomagnetic Storms During Solar Maximum

    NASA Technical Reports Server (NTRS)

    Tsurutani, B. T.; Gonzalez, W. D.

    1998-01-01

    One of the oldest mysteries in geomagnetism is the linkage between solar and geomagnetic activity. The 11-year cycles of both the numbers of sunspots and Earth geomagnetic storms were first noted by Sabine (1852).

  2. Forecasting geomagnetic activity indices

    NASA Astrophysics Data System (ADS)

    Schofield, J.; Wing, S.; Johnson, J. R.

    2007-12-01

    Magnetically active times, e.g., Kp > 5, are notoriously difficult to predict, precisely the times when such predictions are crucial to the space weather users. Taking advantage of the routinely available solar wind measurements at Langrangian point (L1) and nowcast Kps, Kp and Dst forecast models based on neural networks were developed with the focus on improving the forecast for active times. To satisfy different needs and operational constraints, three models were developed: (1) a model that inputs nowcast Kp and solar wind parameters and predicts Kp 1 hr ahead; (2) a model with the same input as model 1 and predicts Kp 4 hr ahead; and (3) a model that inputs only solar wind parameters and predicts Kp 1 hr ahead (the exact prediction lead time depends on the solar wind speed and the location of the solar wind monitor.) Extensive evaluations of these models and other major operational Kp forecast models show that, while the new models can predict Kps more accurately for all activities, the most dramatic improvements occur for moderate and active times. Similar Dst models were developed. Information dynamics analysis of Kp, suggests that geospace is more dominated by internal dynamics near solar minimum than near solar maximum, when it is more directly driven by external inputs, namely solar wind and interplanetary magnetic field (IMF).

  3. Sparkling Geomagnetic Field: Involving Schools in Geomagnetic Research

    NASA Astrophysics Data System (ADS)

    Bailey, Rachel; Leonhardt, Roman; Leichter, Barbara

    2014-05-01

    Solar activity will be reaching a maximum in 2013/2014 as the sun reaches the end of its cycle, bringing with it an opportunity to study in greater detail the effect of solar wind or "space weather" on our planet's magnetic field. Heightened solar activity leads to a larger amount of clouds of energetic particles bombarding the Earth. Although the Earth's magnetic field shields us from most of these particles, the field becomes distorted and compacted by the solar wind, which leads to magnetic storms that we detect from the surface. These storms cause aurorae at higher latitudes and can lead to widespread disruption of communication and navigation equipment all over the Earth when sufficiently strong. This project, "Sparkling Geomagnetic Field," is a part of Austria's Sparkling Science programme, which aims to involve schools in active scientific research to encourage interest in science from a young age. Researchers from the Central Institute for Meteorology and Geodynamics (ZAMG) in Vienna have worked hand-in-hand with three schools across Austria to set up regional geomagnetic stations consisting of state-of-the-art scalar and vector magnetometers to monitor the effects of the solar wind on the geomagnetic field. The students have been an active part of the research team from the beginning, first searching for a suitable location to set up the stations as well as later overseeing the continued running of the equipment and analysing the data output. Through this project the students will gain experience in contemporary scientific methods: data processing and analysis, field work, as well as equipment setup and upkeep. A total of three stations have been established with schools in Innsbruck, Tamsweg and Graz at roughly equal distances across Austria to run alongside the already active station in the Conrad Observatory near Vienna. Data acquisition runs through a data logger and software developed to deliver data in near realtime. This network allows for

  4. Recent developments in the global geomagnetic observatory network

    NASA Astrophysics Data System (ADS)

    Chulliat, A.

    2011-12-01

    Magnetic observatories provide precise and continuous measurements of geomagnetic variations over time scales ranging from one second to more than a century. They have been an essential observational infrastructure for geomagnetic research for about 170 years. A large fraction of magnetic observatories belong to INTERMAGNET (International Real-time Magnetic Observatory Network), a global network founded in the late 1980s which now includes about 115 observatories in 45 countries. INTERMAGNET magnetic observatories comply with strict data quality and timeliness standards and distribute their data through an integrated data information system. Recent years have seen a rapid expansion of the global network: new observatories have been installed in remote locations, such as oceanic islands (St Helena, Easter Island, Tristan da Cunha) or Antarctica (Dome C); ancient observatories have been upgraded to international standards (for example in China and Siberia). This has been prompted by the need to have a more geographically homogeneous network. In parallel, new data products (one second data and quasi-definitive data) are being made available, addressing a wide variety of research needs, and real timeliness is being improved for operational purposes such as space weather monitoring and forecasting. This presentation will provide an overview of these recent developments, focusing on those most relevant to the geomagnetic modeling community, and discuss their expected scientific benefits.

  5. Geomagnetic Effect Caused by 1908 Tunguska Event

    NASA Astrophysics Data System (ADS)

    Losseva, T. V.; Kuzmicheva, M. Y.

    2010-12-01

    results of this current system shows that an unique azimuth of trajectory of the body exists, for which the variations of all three components of the geomagnetic field do not contradict to the observation data. This azimuth is equal to 306 degrees, while other estimates are in the range of 290-344 degrees. This idea of the atmospheric plume ejected along the trajectory and ionization in the upper atmosphere, caused by the following atmospheric oscillations, could explain the geomagnetic effect both in general and locally in Irkutsk observatory: the time delay and the variations of all magnetic field components. Binding of simulation results of observation data also allows us to select the unique trajectory azimuth for Tunguska body. References: [1] Ivanov K.G. The Geomagnetic phenomena, which were being observed on the Irkutsk magnetic observatory, following the explosion of the Tunguska meteorite //Meteoritika. 1961. Iss. XXI. P.46-49 (in Russian). [2] Losseva T., Merkin V., Nemtchinov I. Estimations of the Aeronomical and Electromagnetic Disturbances in the E-layer of the Ionosphere, caused by Tunguska Event // AGU Fall Meeting. 1999. SA32A-09.

  6. Selected Bibliographies and State-of the-Art Review for Socio-cultural Factors in Health. Volume 4: Socio-cultural Factors in Health References. International Health Planning Reference Series.

    ERIC Educational Resources Information Center

    Fraser, Renee White; Shani, Hadasa

    Intended as a companion picce to volume 4 in the Method Series, Sociocultural Factors in Health Planning (CE 024 232), this fourth of six volumes in the International Health Planning Reference Series is a combined literature review and annotated bibliography dealing with social, cultural, and behavioral aspects of delivering, planning, and…

  7. International recommendations for the assessment of autoantibodies to cellular antigens referred to as anti-nuclear antibodies.

    PubMed

    Agmon-Levin, Nancy; Damoiseaux, Jan; Kallenberg, Cees; Sack, Ulrich; Witte, Torsten; Herold, Manfred; Bossuyt, Xavier; Musset, Lucille; Cervera, Ricard; Plaza-Lopez, Aresio; Dias, Carlos; Sousa, Maria José; Radice, Antonella; Eriksson, Catharina; Hultgren, Olof; Viander, Markku; Khamashta, Munther; Regenass, Stephan; Andrade, Luis Eduardo Coelho; Wiik, Allan; Tincani, Angela; Rönnelid, Johan; Bloch, Donald B; Fritzler, Marvin J; Chan, Edward K L; Garcia-De La Torre, I; Konstantinov, Konstantin N; Lahita, Robert; Wilson, Merlin; Vainio, Olli; Fabien, Nicole; Sinico, Renato Alberto; Meroni, Pierluigi; Shoenfeld, Yehuda

    2014-01-01

    Anti-nuclear antibodies (ANA) are fundamental for the diagnosis of autoimmune diseases, and have been determined by indirect immunofluorescence assay (IIFA) for decades. As the demand for ANA testing increased, alternative techniques were developed challenging the classic IIFA. These alternative platforms differ in their antigen profiles, sensitivity and specificity, raising uncertainties regarding standardisation and interpretation of incongruent results. Therefore, an international group of experts has created recommendations for ANA testing by different methods. Two groups of experts participated in this initiative. The European autoimmunity standardization initiative representing 15 European countries and the International Union of Immunologic Societies/World Health Organization/Arthritis Foundation/Centers for Disease Control and Prevention autoantibody standardising committee. A three-step process followed by a Delphi exercise with closed voting was applied. Twenty-five recommendations for determining ANA (1-13), anti-double stranded DNA antibodies (14-18), specific antibodies (19-23) and validation of methods (24-25) were created. Significant differences between experts were observed regarding recommendations 24-25 (p<0.03). Here, we formulated recommendations for the assessment and interpretation of ANA and associated antibodies. Notably, the roles of IIFA as a reference method, and the importance of defining nuclear and cytoplasmic staining, were emphasised, while the need to incorporate alternative automated methods was acknowledged. Various approaches to overcome discrepancies between methods were suggested of which an improved bench-to-bedside communication is of the utmost importance. These recommendations are based on current knowledge and can enable harmonisation of local algorithms for testing and evaluation of ANA and related autoantibodies. Last but not least, new more appropriate terminologies have been suggested. PMID:24126457

  8. Education and Social Change in Korea. Garland Reference Library of Social Science, Volume 513; Reference Books in International Education, Volume 23.

    ERIC Educational Resources Information Center

    Adams, Don; Gottlieb, Esther E.

    This book provides students and scholars with an introduction to Korean education and the dynamics of interchange between the educational system and the rapidly changing Korean society. Attention is given only to the Republic of Korea (South Korea) and includes only English language works of reference. The book contains six chapters: (1)…

  9. Electric utility industry experience with geomagnetic disturbances

    SciTech Connect

    Barnes, P.R.; Rizy, D.T.; McConnell, B.W.; Taylor, E.R. Jr.; Tesche, F.M.

    1991-09-01

    A geomagnetic disturbance (GMD) by its nature occurs globally and almost simultaneously. Severe geomagnetic storms cause problems for electric power systems. The vulnerability of electric power systems to such events has apparently increased during the last 10 to 20 years because power system transmission lines have become more interconnected and have increased in length and because power systems are now operated closer to their limits than in the past. In this report, the experience of electric utilities during geomagnetic storms is examined and analyzed. Measured data, effects on power system components, and power system impacts are considered. It has been found that electric power systems are susceptible to geomagnetically induced earth-surface potential gradients as small as few (2 to 3) volts per kilometer, corresponding to a storm of K-6 intensity over an area of high earth resistivity. The causes and effects are reasonably well understood, but additional research is needed to develop a better understanding of solar-induced geomagnetic storms and the responses of power systems to these types of storms. A better understanding of geomagnetic storms and the power systems` responses to GMDs is needed so that mitigation measures can be implemented that will make power systems less susceptible to severe geomagnetic disturbances. A GMD caused by a large high-altitude nuclear detonation is similar in many ways to that of solar-induced geomagnetic storms except that a nuclear-caused disturbance would be much more intense with a far shorter duration. 49 refs.

  10. Electric Utility Industry Experience with Geomagnetic Disturbances

    SciTech Connect

    Barnes, P.R.

    1991-01-01

    A geomagnetic disturbance (GMD) by its nature occurs globally and almost simultaneously. Severe geomagnetic storms cause problems for electric power systems. The vulnerability of electric power systems to such events has apparently increased during the last 10 to 20 years because power system transmission lines have become more interconnected and have increased in length and because power systems are now operated closer to their limits than in the past. In this report, the experience of electric utilities during geomagnetic storms is examined and analyzed. Measured data, effects on power system components, and power system impacts are considered. It has been found that electric power systems are susceptible to geomagnetically induced earth-surface potential gradients as small as a few (2 to 3) volts per kilometer, corresponding to a storm of K-6 intensity over an area of high earth resistivity. The causes and effects are reasonably well understood, but additional research is needed to develop a better understanding of solar-induced geomagnetic storms and the responses of power systems to these types of storms. A better understanding of geomagnetic storms and the power systems' responses to GMDs is needed so that mitigation measures can be implemented that will make power systems less susceptible to severe geomagnetic disturbances. A GMD caused by a large high-altitude nuclear detonation is similar in many ways to that of solar-induced geomagnetic storms except that a nuclear-caused disturbance would be much more intense with a far shorter duration.

  11. Electric utility industry experience with geomagnetic disturbances

    SciTech Connect

    Barnes, P.R.; Rizy, D.T.; McConnell, B.W. ); Taylor, E.R. Jr. ); Tesche, F.M.

    1991-09-01

    A geomagnetic disturbance (GMD) by its nature occurs globally and almost simultaneously. Severe geomagnetic storms cause problems for electric power systems. The vulnerability of electric power systems to such events has apparently increased during the last 10 to 20 years because power system transmission lines have become more interconnected and have increased in length and because power systems are now operated closer to their limits than in the past. In this report, the experience of electric utilities during geomagnetic storms is examined and analyzed. Measured data, effects on power system components, and power system impacts are considered. It has been found that electric power systems are susceptible to geomagnetically induced earth-surface potential gradients as small as few (2 to 3) volts per kilometer, corresponding to a storm of K-6 intensity over an area of high earth resistivity. The causes and effects are reasonably well understood, but additional research is needed to develop a better understanding of solar-induced geomagnetic storms and the responses of power systems to these types of storms. A better understanding of geomagnetic storms and the power systems' responses to GMDs is needed so that mitigation measures can be implemented that will make power systems less susceptible to severe geomagnetic disturbances. A GMD caused by a large high-altitude nuclear detonation is similar in many ways to that of solar-induced geomagnetic storms except that a nuclear-caused disturbance would be much more intense with a far shorter duration. 49 refs.

  12. A new regard about Surlari National Geomagnetic Observatory

    NASA Astrophysics Data System (ADS)

    Asimopolos, Laurentiu; Asimopolos, Natalia-Silvia; Pestina, Agata-Monica

    2010-05-01

    Geomagnetic field study in Romanian stations has started with irregular measurements in late XIXth century. In 1943, the foundation of Surlari National Geomagnetic Observatory (SNGO) marks the beginning of a new era in the systematic study of geomagnetic field by a continuous registration of its variations and by carrying out standard absolute measurements in a fundamental station. The location of the observatory meets the highest exigencies, being situated in physical-geological conditions of a uniform local field, at a reasonably long distance from human activities. Its laboratories observe strict conditions of non-magnetism, ensuring the possibility of absolute standard measurements (national magnetic standards) for all the units in the country, civil or military, which are endowed with equipment based on geomagnetic metrology. These basic conditions have allowed the observatory to become by developing its initial preoccupations a centre of complex geomagnetic research, constantly involved in national and international issues, promoting new themes in our country and bringing significant contributions. During the last two decades, infrastructure and equipment used in monitoring geomagnetic field at European and planetary level have experienced a remarkable development. New registering techniques have allowed a complete to automate of data acquisition, and sampling step and their precision increased by two classes of size. Systems of transmitting these data in real time to world collecting centres have resulted in the possibility of approaching globalize studies, suitable for following some phenomena at planetary scale. At the same time, a significant development in the procedures of processing primary data has been registered, based on standardized programmes. The new stage of this fundamental research, largely applicable in various fields, is also marked by the simultaneous observation of space-time distribution of terrestrial electromagnetic field by means of

  13. Geophysical excitation of nutation and geomagnetic jerks

    NASA Astrophysics Data System (ADS)

    Vondrák, Jan; Ron, Cyril

    2014-05-01

    Recently Zinovy Malkin (2013) proposed that the observed changes of Free Core Nutation parameters (phase, amplitude) might be related to geomagnetic jerks (rapid changes of the secular variations of geomagnetic field). We tested this hypothesis and found that if the numerical integration of Brzezinski broad-band Liouville equations of atmospheric/oceanic excitations is re-initialized at the epochs of geomagnetic jerks, the agreement between the integrated and observed celestial pole offsets is improved significantly. This approach however tacitly assumes that the influence of geomagnetic jerks has a stepwise character, which is physically not acceptable. The present study continues in this effort by introducing a simple continuous excitation function (hypothetically due to geomagnetic jerks). The results of numerical integration of atmospheric/oceanic excitations plus this newly introduced excitation are then compared with the observed celestial pole offsets.

  14. Causal relationships between solar and geomagnetic cycles

    NASA Astrophysics Data System (ADS)

    Ponyavin, D. I.

    2006-12-01

    Sunspots are sui generis "hot spots" that display the most responsive regions to solar cycle changes. Rudolf Wolf in 1848 derived a simple measure of solar cyclicity by counting a number of sunspots and sunspot groups at the solar disk. Edward Sabine in 1852 announced that geomagnetic cycle was "absolutely identical" to solar cycle. However geomagnetic and sunspot indices due to their different nature do not exhibit similar variations and often manifest out of phase behavior. Long-term sunspot and geomagnetic time-series were studied using wavelet transforms and recurrence plot techniques. We have analyzed similarities and relationships between sunspot and geomagnetic cycles in order to find recurrence, synchronization and phase differences on interannual scale. Predictive schemes of the current and future solar cycles using geomagnetic proxies were analyzed and discussed.

  15. Trial-by-trial updating of an internal reference in discrimination tasks: evidence from effects of stimulus order and trial sequence.

    PubMed

    Dyjas, Oliver; Bausenhart, Karin M; Ulrich, Rolf

    2012-11-01

    In psychophysics, participants are often asked to discriminate between a constant standard and a variable comparison. Previous studies have shown that discrimination performance is better when the comparison follows, rather than precedes, the standard. Prominent difference models of psychophysics and decision making cannot easily explain this order effect. However, a simple extension of this model class involving dynamical updating of an internal reference accounts for this order effect. In addition, this Internal Reference Model (IRM) predicts sequential response effects. We examined the predictions of IRM in two duration discrimination experiments. The obtained results are in agreement with the predictions of IRM, suggesting that participants update their internal reference on every trial. Additional simulations show that IRM also accounts for the negative sequential effects observed in single-stimulus paradigms. PMID:23055085

  16. Blood-brain barrier transport of butanol and water relative to N-isopropyl-p-iodoamphetamine as the internal reference

    SciTech Connect

    Pardridge, W.M.; Fierer, G.

    1985-06-01

    The literature regarding the blood--brain barrier (BBB) transport of butanol is conflicting as studies report both incomplete and complete extraction of butanol by the brain. In this work the BBB transport of both (/sup 14/C)butanol and (/sup 3/H)water was studied using the carotid injection technique in conscious and in ketamine- or pentobarbital-anesthetized rats employing N-isopropyl-p-(/sup 125/I)iodoamphetamine ((/sup 125/I)IMP) as the internal reference and as a fluid microsphere. The three isotopes (/sup 3/H, /sup 125/I, /sup 14/C) were conveniently counted simultaneously in a liquid scintillation spectrometer. IMP is essentially completely sequestered by the brain for at least 1 min in conscious rats and for 2 min in anesthetized animals. Butanol extraction by rat forebrain is not flow limited but ranges between 77 +/- 1 and 87 +/- 1% for the three conditions. The permeability-surface area product/cerebral blood flow ratio of butanol and water in rat forebrain remains relatively constant, despite a twofold increase in cerebral blood flow in conscious relative to pentobarbital-anesthetized rats. The absence of an inverse relationship between flow and butanol or water extraction is consistent with capillary recruitment being the principal mechanism underlying changes in cerebral blood flow in anesthesia. The diffusion restriction of BBB transport of butanol in some regions, but not in others, necessitates a careful regional analysis of BBB permeability to butanol prior to usage of this compound as a cerebral blood flow marker.

  17. Problems in functioning from the patient perspective using the International Classification of Functioning, Disability and Health (ICF) as a reference.

    PubMed

    Gradinger, Felix; Köhler, Barbara; Khatami, Ramin; Mathis, Johannes; Cieza, Alarcos; Bassetti, Claudio

    2011-03-01

    We conducted a qualitative, multicenter study using a focus group design to explore the lived experiences of persons with any kind of primary sleep disorder with regard to functioning and contextual factors using six open-ended questions related to the International Classification of Functioning, Disability and Health (ICF) components. We classified the results using the ICF as a frame of reference. We identified the meaningful concepts within the transcribed data and then linked them to ICF categories according to established linking rules. The six focus groups with 27 participants yielded a total of 6986 relevant concepts, which were linked to a total of 168 different second-level ICF categories. From the patient perspective, the ICF components: (1) Body Functions; (2) Activities & Participation; and (3) Environmental Factors were equally represented; while (4) Body Structures appeared poignantly less frequently. Out of the total number of concepts, 1843 concepts (26%) were assigned to the ICF component Personal Factors, which is not yet classified but could indicate important aspects of resource management and strategy development of those who have a sleep disorder. Therefore, treatment of patients with sleep disorders must not be limited to anatomical and (patho-)physiological changes, but should also consider a more comprehensive view that includes patient's demands, strategies and resources in daily life and the contextual circumstances surrounding the individual. PMID:20642749

  18. Global energy and water cycle experiment (GEWEX) continental-scale international project (GCIP); reference data sets CD-ROM

    USGS Publications Warehouse

    Rea, Alan; Cederstrand, Joel R.

    1994-01-01

    The data sets on this compact disc are a compilation of several geographic reference data sets of interest to the global-change research community. The data sets were chosen with input from the Global Energy and Water Cycle Experiment (GEWEX) Continental-Scale International Project (GCIP) Data Committee and the GCIP Hydrometeorology and Atmospheric Subpanels. The data sets include: locations and periods of record for stream gages, reservoir gages, and meteorological stations; a 500-meter-resolution digital elevation model; grid-node locations for the Eta numerical weather-prediction model; and digital map data sets of geology, land use, streams, large reservoirs, average annual runoff, average annual precipitation, average annual temperature, average annual heating and cooling degree days, hydrologic units, and state and county boundaries. Also included are digital index maps for LANDSAT scenes, and for the U.S. Geological Survey 1:250,000, 1:100,000, and 1:24,000-scale map series. Most of the data sets cover the conterminous United States; the digital elevation model also includes part of southern Canada. The stream and reservoir gage and meteorological station files cover all states having area within the Mississippi River Basin plus that part of the Mississippi River Basin lying within Canada. Several data-base retrievals were processed by state, therefore many sites outside the Mississippi River Basin are included.

  19. [Determination of Sb and Bi in 24 international geological reference materials by using pressurized acid digestion-ICP-MS].

    PubMed

    Hu, Zhao-chu; Gao, Shan; Liu, Xiao-ming; Yuan, Hong-lin; Liu, Ye; Diwu, Chun-rong

    2007-12-01

    The authors studied in detail the memory effect of Bi, Sb, As and Te in ICP-MS. The produced memory effects of these element were in the order of Bi>Sb>Te>As. Bi was seriously adsorbed by the polypropylene sample storing bottle and the sample introduction system in the low nitric acid medium (0.01%-1% HNO3). The washout effect of 0.1% HF was found to be better than those of 6% HNO3 and 0.1% HClO4. Under the given experiment conditions, the instrumental limit of detection was 0.001 and 0.0001 ng x mL(-1) for Sb and Bi, respectively. The authors report the determination of Sb and Bi in 24 international geological reference materials by using pressurized acid digestion-ICP-MS (including AGV-2, BHVO-2, BCR-2, etc.). Most of the results were found to be in reasonable agreement with the reported values in the literature. The authors' determined values of Sb for GSR-1 (granite; 0.30 microg x g(-1)) and JP-1 (peridotite; 0.045 microg x g(-1)) are obviously higher than those reported values. This is attributed to the efficient pressurized acid digestion, which is generally much more efficient than conventional wet digestions for insoluble minerals. PMID:18330312

  20. Proceedings of the XIIIth IAGA Workshop on Geomagnetic Observatory Instruments, Data Acquisition, and Processing

    USGS Publications Warehouse

    Love, Jeffrey J.

    2009-01-01

    The thirteenth biennial International Association of Geomagnetism and Aeronomy (IAGA) Workshop on Geomagnetic Observatory Instruments, Data Acquisition and Processing was held in the United States for the first time on June 9-18, 2008. Hosted by the U.S. Geological Survey's (USGS) Geomagnetism Program, the workshop's measurement session was held at the Boulder Observatory and the scientific session was held on the campus of the Colorado School of Mines in Golden, Colorado. More than 100 participants came from 36 countries and 6 continents. Preparation for the workshop began when the USGS Geomagnetism Program agreed, at the close of the twelfth workshop in Belsk Poland in 2006, to host the next workshop. Working under the leadership of Alan Berarducci, who served as the chairman of the local organizing committee, and Tim White, who served as co-chairman, preparations began in 2007. The Boulder Observatory was extensively renovated and additional observation piers were installed. Meeting space on the Colorado School of Mines campus was arranged, and considerable planning was devoted to managing the many large and small issues that accompany an international meeting. Without the devoted efforts of both Alan and Tim, other Geomagnetism Program staff, and our partners at the Colorado School of Mines, the workshop simply would not have occurred. We express our thanks to Jill McCarthy, the USGS Central Region Geologic Hazards Team Chief Scientist; Carol A. Finn, the Group Leader of the USGS Geomagnetism Program; the USGS International Office; and Melody Francisco of the Office of Special Programs and Continuing Education of the Colorado School of Mines. We also thank the student employees that the Geomagnetism Program has had over the years and leading up to the time of the workshop. For preparation of the proceedings, thanks go to Eddie and Tim. And, finally, we thank our sponsors, the USGS, IAGA, and the Colorado School of Mines.

  1. Ready Reference.

    ERIC Educational Resources Information Center

    Koltay, Emery

    2001-01-01

    Includes four articles that relate to ready reference, including a list of publishers' toll-free telephone numbers and Web sites; how to obtain an ISBN (International Standard Book Number) and an ISSN (International Standard Serial Number); and how to obtain an SAN (Standard Address Number), for organizations that are involved in the book…

  2. Three Decades of Peace Education around the World: An Anthology. Garland Reference Library of Social Science, Volume 600. Reference Books in International Education, Volume 24.

    ERIC Educational Resources Information Center

    Burns, Robin J., Ed.; Aspeslagh, Robert, Ed.

    The Peace Education Commission (PEC) of the International Peace Research Association (IPRA) has been the forum for peace educators to come together, to exchange and to share ideas, materials and experiences over three decades. This book draws from key papers from different areas and times of peace education work to show the richness of ideas and…

  3. History of the geomagnetic field

    USGS Publications Warehouse

    Doell, Richard R.

    1969-01-01

    Direct measurements of the direction and strength of the earth's magnetic field have provided a knowledge of the field's form and behavior during the last few hundreds of years. For older times, however, it has been necessary to measure the magnetism of certain rocks to learn what the geomagnetic field was like. For example, when a lava flow solidifies (at temperatures near 1000??C) and cools through the Curie point of the magnetic minerals contained in it (around 500??C) it acquires a remanent magnetism that is (1) very weak, (2) very stablel, (3) paralle to the direction of the ambient geomagnetic field, and (4) proportional in intensity to the ambient field. Separating, by various analytical means, this magnetization from other 'unwanted' magnetizations has allowed paleomagnetists to study the historical and prehistorical behavior of the earth's field. It has been learned, for example, that the strength of the field was almost twice its present value 2000 years ago and that it has often completely reversed its polarity. Paleo-magnetists have also confirmed that most oceans are, geologically speaking, relatively new features, and that the continents have markedly changed their positions over the surface of the earth. ?? 1969 The American Institute of Physics.

  4. Geomagnetic Data from the US Magnetic Observatory Network

    NASA Technical Reports Server (NTRS)

    Herzog, Donald C.

    1992-01-01

    The United States operates a network of, at present, 13 ground-based magnetic observatories. Continuous, one-minute digital vector and scalar geomagnetic field values have been recorded for the last decade, and extend about five years further back for several stations. Periodic, 3-component absolute measurements of the magnetic field are made to provide baseline reference data with which to determine calibrated field view values at all intervals. These data are now being made available on CD-ROM. The quality of the data depends upon a number of factors, including the types of instrumentation used to monitor and measure the field, the procedures and equipment used to collect and process the data, and the quality controls employed to check the data for erroneous values. These various factors are described here for the U.S. digital geomagnetic observatory data. The observatories have been undergoing an evolution over the last 15 years that will continue to significantly improve the accuracy, precision, and availability of geomagnetic data.

  5. Study of Geomagnetic Anomalies Related to Earthquakes at Pisco Peru 2007 (M=8.0) and at Taiwan 2009 (M= 6.4) (Invited)

    NASA Astrophysics Data System (ADS)

    Yumoto, K.; Takla, E.; Ishitsuka, J.; Rosales, D.; Dutra, S. L.; Liu, J. G.; Kakinami, Y.; Uozumi, T.; Abe, S.

    2010-12-01

    The Space Environment Research Center (SERC), Kyushu University deployed the MAGnetic Data Acqusition System (MAGDAS) at 53 stations along the 210- and 96-degree magnetic meridians (MM) and the magnetic Dip equator, and three FM-CW radars along the 210-degree MM during the International Heliophysical Year (IHY) period of 2005-2009 (see http://magdas.serc.kyushu-u.ac.jp/ and http://magdas2.serc.kyushu-u.ac.jp/). By analyzing these new MAGDAS data, we can perform a real-time monitoring for understanding the plasma and electromagnetic environment changes in geospace and lithosphere. In the present paper, we will introduce geomagnetic anomalies associated with larger earthquakes (EQs), observed at the MAGDAS stations. The first event is the Pisco earthquake (M=8.0) on August 15, 2007, which was the largest shallow earthquake and affected the coastal area south of Lima for 250 years. This occurred at the boundary between the Nazca and South American tectonic plates. Geomagnetic data from the MAGDAS Ancon (ANC; about 180 km from the epicenter), the INTERMAGNET Huancayo (HUA;about 190 km from the epicenter) and the MAGDAS Eusebio (EUS; about 39°east from ANC) stations were analyzed to clarify if there is a relation between the geomagnetic variations and the tectonic activities at Peru during 2007. Our results indicate both long- (several months) and short-term (daily) anomalous geomagnetic variations (H and Z components) in relation with these seismic activities. In addition, there were anomalous signals of Pc 3 polarization (Z/H) a few months before the onset of seismic activities. The second event is the Taiwan earthquake of M=6.4 on the Richter scale, which occurred at depth ≈ 45 km, on 19th of December 2009. The epicenter was located about 20 Km away from our MAGDAS Hualien (HLN) station. The MAGDAS Amami-ohshima (AMA) station in Japan was used as a remote reference station. The geomagnetic components (H, D and Z) at the HLN station showed baseline fluctuations

  6. Improved geomagnetic referencing in the Arctic environment

    USGS Publications Warehouse

    Poedjono, B.; Beck, N.; Buchanan, A. C.; Borri, L.; Maus, S.; Finn, Carol; Worthington, Bill; White, Tim

    2016-01-01

    Geomagnetic referencing uses the Earth’s magnetic field to determine accurate wellbore positioning essential for success in today's complex drilling programs, either as an alternative or a complement to north-seeking gyroscopic referencing. However, fluctuations in the geomagnetic field, especially at high latitudes, make the application of geomagnetic referencing in those areas more challenging. Precise crustal mapping and the monitoring of real-time variations by nearby magnetic observatories is crucial to achieving the required geomagnetic referencing accuracy. The Deadhorse Magnetic Observatory (DED), located at Prudhoe Bay, Alaska, has already played a vital role in the success of several commercial ventures in the area, providing essential, accurate, real-time data to the oilfield drilling industry. Geomagnetic referencing is enhanced with real-time data from DED and other observatories, and has been successfully used for accurate wellbore positioning. The availability of real-time geomagnetic measurements leads to significant cost and time savings in wellbore surveying, improving accuracy and alleviating the need for more expensive surveying techniques. The correct implementation of geomagnetic referencing is particularly critical as we approach the increased activity associated with the upcoming maximum of the 11-year solar cycle. The DED observatory further provides an important service to scientific communities engaged in studies of ionospheric, magnetospheric and space weather phenomena.

  7. Space Weather Monitoring for ISS Geomagnetic Storm Studies

    NASA Technical Reports Server (NTRS)

    Minow, Joseph I.; Parker, Linda Neergaard

    2013-01-01

    The International Space Station (ISS) space environments community utilizes near real time space weather data to support a variety of ISS engineering and science activities. The team has operated the Floating Potential Measurement Unit (FPMU) suite of plasma instruments (two Langmuir probes, a floating potential probe, and a plasma impedance probe) on ISS since 2006 to obtain in-situ measurements of plasma density and temperature along the ISS orbit and variations in ISS frame potential due to electrostatic current collection from the plasma environment (spacecraft charging) and inductive (vxB) effects from the vehicle motion across the Earth s magnetic field. An ongoing effort is to use FPMU for measuring the ionospheric response to geomagnetic storms at ISS altitudes and investigate auroral charging of the vehicle as it passes through regions of precipitating auroral electrons. This work is challenged by restrictions on FPMU operations that limit observation time to less than about a third of a year. As a result, FPMU campaigns ranging in length from a few days to a few weeks are typically scheduled weeks in advance for ISS engineering and payload science activities. In order to capture geomagnetic storm data under these terms, we monitor near real time space weather data from NASA, NOAA, and ESA sources to determine solar wind disturbance arrival times at Earth likely to be geoeffective (including coronal mass ejections and high speed streams associated with coronal holes) and activate the FPMU ahead of the storm onset. Using this technique we have successfully captured FPMU data during a number of geomagnetic storm periods including periods with ISS auroral charging. This presentation will describe the strategies and challenges in capturing FPMU data during geomagnetic storms, the near real time space weather resources utilized for monitoring the space weather environment, and provide examples of auroral charging data obtained during storm operations.

  8. Geomagnetic Observatory Data for Real-Time Applications

    NASA Astrophysics Data System (ADS)

    Love, J. J.; Finn, C. A.; Rigler, E. J.; Kelbert, A.; Bedrosian, P.

    2015-12-01

    The global network of magnetic observatories represents a unique collective asset for the scientific community. Historically, magnetic observatories have supported global magnetic-field mapping projects and fundamental research of the Earth's interior and surrounding space environment. More recently, real-time data streams from magnetic observatories have become an important contributor to multi-sensor, operational monitoring of evolving space weather conditions, especially during magnetic storms. In this context, the U.S. Geological Survey (1) provides real-time observatory data to allied space weather monitoring projects, including those of NOAA, the U.S. Air Force, NASA, several international agencies, and private industry, (2) collaborates with Schlumberger to provide real-time geomagnetic data needed for directional drilling for oil and gas in Alaska, (3) develops products for real-time evaluation of hazards for the electric-power grid industry that are associated with the storm-time induction of geoelectric fields in the Earth's conducting lithosphere. In order to implement strategic priorities established by the USGS Natural Hazards Mission Area and the National Science and Technology Council, and with a focus on developing new real-time products, the USGS is (1) leveraging data management protocols already developed by the USGS Earthquake Program, (2) developing algorithms for mapping geomagnetic activity, a collaboration with NASA and NOAA, (3) supporting magnetotelluric surveys and developing Earth conductivity models, a collaboration with Oregon State University and the NSF's EarthScope Program, (4) studying the use of geomagnetic activity maps and Earth conductivity models for real-time estimation of geoelectric fields, (5) initiating geoelectric monitoring at several observatories, (6) validating real-time estimation algorithms against historical geomagnetic and geoelectric data. The success of these long-term projects is subject to funding constraints

  9. IMGT, the international ImMunoGeneTics information system, http://imgt.cines.fr: the reference in immunoinformatics.

    PubMed

    Lefranc, Marie-Paule; Giudicelli, Véronique; Ginestoux, Chantal; Chaume, Denys

    2003-01-01

    IMGT, the international ImMunoGeneTics information system (http://imgt.cines.fr), is a high quality integrated information system specializing in immunoglobulins (IG), T cell receptors (TR), major histocompatibility complex (MHC) and related proteins of the immune system of human and other vertebrates, created in 1989, by the Laboratoire d'ImmunoGénétique Moléculaire (LIGM), at the Université Montpellier II, CNRS, Montpellier, France. IMGT is the global reference in immunogenetics and immunoinformatics and provides a common access to standardized data which include nucleotide and protein sequences, oligonucleotide primers, gene maps, genetic polymorphisms, specificities, 2D and 3D structures. IMGT includes three sequence databases (IMGT/LIGM-DB, IMGT/MHC-DB hosted at EBI, IMGT/PRIMER-DB), one genome database (IMGT/GENE-DB), one 3D structure database (IMGT/3Dstructure-DB), Web resources comprising 8000 HTML pages ("IMGT Marie-Paule page") and interactive tools for sequence (IMGT/V-QUEST, IMGT/JunctionAnalysis, IMGT/Allele-Align, IMGT/PhyloGene) and genome (IMGT/GeneSearch, IMGT/GeneView, IMGT/LocusView) analysis. IMGT data are expertly annotated according to the rules of the IMGT Scientific chart, based on the IMGT-ONTOLOGY concepts. IMGT tools are particularly useful for the analysis of the IG and TR repertoires in physiological normal and pathological situations. IMGT has important applications in medical research (repertoire analysis in autoimmune diseases, AIDS, leukemias, lymphomas, myelomas), biotechnology related to antibody engineering (phage displays, combinatorial libraries) and therapeutic approaches (graft, immunotherapy). IMGT is freely available at http://imgt.cines.fr. PMID:14663966

  10. Frequency of Proterozoic geomagnetic superchrons

    NASA Astrophysics Data System (ADS)

    Driscoll, Peter E.; Evans, David A. D.

    2016-03-01

    Long-term geodynamo evolution is expected to respond to inner core growth and changing patterns of mantle convection. Three geomagnetic superchrons, during which Earth's magnetic field maintained a near-constant polarity state through tens of Myr, are known from the bio/magnetostratigraphic record of Phanerozoic time, perhaps timed according to supercontinental episodicity. Some geodynamo simulations incorporating a much smaller inner core, as would have characterized Proterozoic time, produce field reversals at a much lower rate. Here we compile polarity ratios of site means within a quality-filtered global Proterozoic paleomagnetic database, according to recent plate kinematic models. Various smoothing parameters, optimized to successfully identify the known Phanerozoic superchrons, indicate 3-10 possible Proterozoic superchrons during the 1300 Myr interval studied. Proterozoic geodynamo evolution thus appears to indicate a relatively narrow range of reversal behavior through the last two billion years, implying either remarkable stability of core dynamics over this time or insensitivity of reversal rate to core evolution.

  11. Intense geomagnetic storms: A study

    NASA Astrophysics Data System (ADS)

    Silbergleit, Virginia

    In the pipes and the lines of the transmission of the electrical energy, the route of the currents through them, causes a diminution of the life utility of the same one. The intense storms are studied, because these are induced quickly to the ionospheric systems that they change, obtaining great induced telluric currents (or GICs). Also the Akasofús parameter based on the time for periods of strong and moderate magnetic storms during the last 10 years is calculated. The method also standardizes the parameters of the storm: electron flow between 30-300 KeV, z component of the magnetic field (Bz), the solar Wind velocity (v), indices AE and AL. Also, the decay time of the ring current (which is different during the main and the recovery phase from of the geomagnetic disturbances) are calculated.

  12. The Internal/External Frame of Reference Model of Self-Concept and Achievement Relations: Age-Cohort and Cross-Cultural Differences

    ERIC Educational Resources Information Center

    Marsh, Herbert W.; Abduljabbar, Adel Salah; Parker, Philip D.; Morin, Alexandre J. S.; Abdelfattah, Faisal; Nagengast, Benjamin; Möller, Jens; Abu-Hilal, Maher M.

    2015-01-01

    The internal/external frame of reference (I/E) model and dimensional comparison theory posit paradoxical relations between achievement (ACH) and self-concept (SC) in mathematics (M) and verbal (V) domains; ACH in each domain positively affects SC in the matching domain (e.g., MACH to MSC) but negatively in the nonmatching domain (e.g., MACH to…

  13. Extension of the Internal/External Frame of Reference Model of Self-Concept Formation: Importance of Native and Nonnative Languages for Chinese Students.

    ERIC Educational Resources Information Center

    Hau, Kit-Tai; Kong, Chit-Kwong; Marsh, Herbert W.; Cheng, Zi-Juan

    The internal/external frame of reference (I/E) model of self-concept formation was extended by relating Chinese, English, and mathematics achievement to Chinese, English, and mathematics self-concepts in a 5-year longitudinal study based on a large (N=9,482) representative sample of Hong Kong high school students. Tests of the I/E model are…

  14. Is the geomagnetic map imprinted in pre-emergent egg?

    PubMed

    Liboff, A R

    2016-01-01

    Although it is well-accepted that the geomagnetic field (GMF) plays an important role in animal navigation and migration, key problems remain unanswered. To explain the puzzling ability of hatchlings to embark on unexplored migrational journeys we hypothesize that mothers who have previously navigated the trip enable their offspring by direct transfer of route information to their eggs prior to hatching. The freshly hatched animal registers the local GMF as a reference point before embarking on the journey the mother has prepared for it. This process represents a novel type of biological cycle that finesses the need to treat questions such as natal homing and route parameters separately. PMID:26192067

  15. Range indices of geomagnetic activity

    USGS Publications Warehouse

    Stuart, W.F.; Green, A.W., Jr.

    1988-01-01

    The simplest index of geomagnetic activity is the range in nT from maximum to minimum value of the field in a given time interval. The hourly range R was recommended by IAGA for use at observatories at latitudes greater than 65??, but was superceded by AE. The most used geomagnetic index K is based on the range of activity in a 3 h interval corrected for the regular daily variation. In order to take advantage of real time data processing, now available at many observatories, it is proposed to introduce a 1 h range index and also a 3 h range index. Both will be computed hourly, i.e. each will have a series of 24 per day, the 3 h values overlapping. The new data will be available as the range (R) of activity in nT and also as a logarithmic index (I) of the range. The exponent relating index to range in nT is based closely on the scale used for computing K values. The new ranges and range indices are available, from June 1987, to users in real time and can be accessed by telephone connection or computer network. Their first year of production is regarded as a trial period during which their value to the scientific and commercial communities will be assessed, together with their potential as indicators of regional and global disturbances' and in which trials will be conducted into ways of eliminating excessive bias at quiet times due to the rate of change of the daily variation field. ?? 1988.

  16. Deciphering records of geomagnetic reversals

    NASA Astrophysics Data System (ADS)

    Valet, Jean-Pierre; Fournier, Alexandre

    2016-06-01

    Polarity reversals of the geomagnetic field are a major feature of the Earth's dynamo. Questions remain regarding the dynamical processes that give rise to reversals and the properties of the geomagnetic field during a polarity transition. A large number of paleomagnetic reversal records have been acquired during the past 50 years in order to better constrain the structure and geometry of the transitional field. In addition, over the past two decades, numerical dynamo simulations have also provided insights into the reversal mechanism. Yet despite the large paleomagnetic database, controversial interpretations of records of the transitional field persist; they result from two characteristics inherent to all reversals, both of which are detrimental to an ambiguous analysis. On the one hand, the reversal process is rapid and requires adequate temporal resolution. On the other hand, weak field intensities during a reversal can affect the fidelity of magnetic recording in sedimentary records. This paper is aimed at reviewing critically the main reversal features derived from paleomagnetic records and at analyzing some of these features in light of numerical simulations. We discuss in detail the fidelity of the signal extracted from paleomagnetic records and pay special attention to their resolution with respect to the timing and mechanisms involved in the magnetization process. Records from marine sediments dominate the database. They give rise to transitional field models that often lead to overinterpret the data. Consequently, we attempt to separate robust results (and their subsequent interpretations) from those that do not stand on a strong observational footing. Finally, we discuss new avenues that should favor progress to better characterize and understand transitional field behavior.

  17. Comparison of Ionospheric TEC Derived from GPS and IRI 2012 Model during Geomagnetic Storms at Indonesia

    NASA Astrophysics Data System (ADS)

    Marlia, Dessi; Wu, Falin

    2016-07-01

    This paper investigates the variations of vertical Total Electron Content (VTEC) at Manado, Indonesia (geographic coordinates : lat 1.34 ° S and long 124.82 ° E) for period 2013. The GPS measured TEC is compared with the TEC derived from the IRI (International Reference Ionosphere) 2012 model. Vertical TEC measurements obtained from dual frequency GPS receiver that is GISTM (GPS Ionospheric Scintillations and TEC monitor). Variation of TEC validate to IRI 2012 model at Manado station has been compared with the model for three different topside of electron density namely NeQuick, IRI-01-Corr and IRI2001.There is a need to investigation on diurnal, seasonal variations, solar activity dependence of TEC and including effects of space weather related events to TEC and modeling of TEC. In this paper, diurnal and seasonal variations of VTEC and the effect of VTEC due to space weather events like Geomagnetic storms are analyzed. The result show that the TEC prediction using IRI-2001 model overestimated the GPS TEC measurements, while IRI-NeQuick and IRI-01-corr show a tendency to underestimates the observed TEC during the day time particularly in low latitude region in the maximum solar activity period (2013). The variations of VTEC during 17th March, 2013, 29th June, 2013 storms are analyzed. During 17th March,2013 storm enhancement in VTEC with Kp value 6 and Disturbance storm index (DST) -132 nT. During 29th June, 2013 storm VTEC depletion with value 7 and DST -98 nT. Significant deviations in VTEC during the main phase of the storms are observed. It is found that the response of ionospheric TEC consist of effects of both enhancement and depletions in ionospheric structures (positive and negative storm). Keywords: TEC ionosphere, GPS, GISTM, IRI 2012 model, solar activity, geomagnetic storm

  18. Solar wind and geomagnetism: toward a standard classification of geomagnetic activity from 1868 to 2009

    NASA Astrophysics Data System (ADS)

    Zerbo, J. L.; Amory Mazaudier, C.; Ouattara, F.; Richardson, J. D.

    2012-02-01

    We examined solar activity with a large series of geomagnetic data from 1868 to 2009. We have revisited the geomagnetic activity classification scheme of Legrand and Simon (1989) and improve their scheme by lowering the minimum Aa index value for shock and recurrent activity from 40 to 20 nT. This improved scheme allows us to clearly classify about 80% of the geomagnetic activity in this time period instead of only 60% for the previous Legrand and Simon classification.

  19. Geomagnetic main field modeling using magnetohydrodynamic constraints

    NASA Technical Reports Server (NTRS)

    Estes, R. H.

    1985-01-01

    The influence of physical constraints are investigated which may be approximately satisfied by the Earth's liquid core on models of the geomagnetic main field and its secular variation. A previous report describes the methodology used to incorporate nonlinear equations of constraint into the main field model. The application of that methodology to the GSFC 12/83 field model to test the frozen-flux hypothesis and the usefulness of incorporating magnetohydrodynamic constraints for obtaining improved geomagnetic field models is described.

  20. How the geomagnetic field vector reverses polarity

    USGS Publications Warehouse

    Prevot, M.; Mankinen, E.A.; Gromme, C.S.; Coe, R.S.

    1985-01-01

    A highly detailed record of both the direction and intensity of the Earth's magnetic field as it reverses has been obtained from a Miocene volcanic sequence. The transitional field is low in intensity and is typically non-axisymmetric. Geomagnetic impulses corresponding to astonishingly high rates of change of the field sometimes occur, suggesting that liquid velocity within the Earth's core increases during geomagnetic reversals. ?? 1985 Nature Publishing Group.

  1. Geomagnetic Storm Main Phase effect on the Equatorial Ionosphere as measured from GPS observations at Ile-Ife

    NASA Astrophysics Data System (ADS)

    Olabode, Ayomide; Ariyibi, Emmanuel

    2016-07-01

    The effect of the main phase of two intense geomagnetic storm events which occurred on August 5-6 and September 26-27, 2011 on the equatorial ionosphere have been investigated using Global Positioning System (GPS) data obtained from an Ile-Ife station (geomagnetic lat. 9.84°N, long. 77.25°E). The WinTEC-P and GPS-TEC analysis software programs were used to process the GPS data to obtain Total Electron Content (TEC) and Scintillation Index (S4). TEC profiles during the main phase of the two geomagnetically disturbed days were compared with quiet time average profiles to examine the response of the equatorial ionosphere. International Reference Ionosphere (IRI) 2012 TEC model was also obtained from Virtual Ionosphere, Thermosphere, Mesosphere Observatory (VITMO) and the extents of deviation from measured GPS-derived TEC were examined for the main phase of the storm events. The results showed that the intensity of both storm events during the main phase which occurred at night-time correlated well with a strong southward direction of the z-component of the Interplanetary Magnetic Field (IMF-Bz) and Solar Wind Speed (Vsw), with the Disturbance storm time (Dst) profile showing multiple step development. TEC depletion was observed during the main phase of the August 5-6, 2011 storm event with TEC recording a maximum value of 9.31 TECU. A maximum TEC value of 55.8 TECU was recorded during the main phase of the September 26-27, 2011 storm event depicting TEC enhancement. Significant scintillation index value of 0.57 was observed when the main phase started on August 5-6, 2011 followed by a prolonged suppression while there was less significant scintillation impact on September 26-27, 2011 with a maximum value of 0.33. The study concluded that the intensification of the ring current during the main phase of geomagnetic storm events was responsible for the intensity of the storm events causing large variations in TEC and significant scintillation phenomenon.

  2. Geomagnetic field effects of the Chelyabinsk meteoroid

    NASA Astrophysics Data System (ADS)

    Chernogor, L. F.

    2014-09-01

    An analysis was conducted of time variations in geomagnetic field components on the day of the Chelyabinsk meteorite event (February 15, 2013) and on control days (February 12 and 16, 2013). The analysis uses the data collected by magnetic observatories in Novosibirsk, Almaty, Kyiv, and Lviv. The distance R from the explosion site to the observatories varies in the range 1200-2700 km. The flyby and explosion of the Chelyabinsk cosmic body is found to have been accompanied by variations mainly in the horizontal component of the geomagnetic field. The variations are quasi-periodic with a period of 30-40 min, an amplitude of 0.5-2 nT for R ≈ 2700-1200 km, respectively, and a duration of 2-3 h. The horizontal velocity of the geomagnetic field disturbances is close to 260-370 m/s. A theoretical model of wave disturbances is proposed. According to the model, wave disturbances in the geomagnetic field are caused (a) by the motion of the gravity wave generated in the atmosphere by the falling space body and (b) by traveling ionospheric disturbances, which modulate the ionospheric current at dynamo altitudes. The calculated amplitudes of the wave disturbances are 0.6-1.8 nT for R ≈ 2700-1200 km, respectively. The estimates are in good agreement with the observational data. Disturbances in the geomagnetic field level (geomagnetic pulsations) in the period range 1-1000 s are negligible (less than 1 nT).

  3. Geomagnetic disturbance effects on power systems

    SciTech Connect

    Albertson, V.D.; Bozoki, B.; Feero, W.E.; Kappenman, J.G.; Larsen, E.V.; Nordell, D.E.; Ponder, J.; Prabhakara, F.S.; Thompson, K.; Walling, R.

    1993-07-01

    In the northern hemisphere, the aurora borealis is visual evidence of simultaneous fluctuations in the earth's magnetic field (geomagnetic field). These geomagnetic disturbances (GMD's), or geomagnetic storms, can affect a number of man-made systems, including electric power systems. The GMD's are caused by the electromagnetic interaction of the solar wind plasma of protons and electrons with the geomagnetic field. These dynamic impulses in the solar wind are due to solar flares, coronal holes, and disappearing filaments, and reach the earth from one to six days after being emitted by a solar event. Instances of geomagnetic storms affecting telegraph systems were noted in England in 1846, and power system disturbances linked to GMD's were first reported in the United States in 1940. This Working Group report is a summary of the state of knowledge and research activity to the present time, and covers the GMD/Geomagnetically-induced currents (GIC) phenomena, transformer effects, the impact on generators, protective relay effects, and communication system effects. It also summarizes modeling and predicting GIC, measuring and monitoring GIC, mitigation methods, system operating guidelines during GMD's, and alerting and forecasting procedures and needs for the power industry.

  4. Ergodicity of the recent geomagnetic field

    NASA Astrophysics Data System (ADS)

    De Santis, A.; Qamili, E.; Cianchini, G.

    2011-06-01

    The geomagnetic field is a fundamental property of our planet: its study would allow us to understand those processes of Earth's interior, which act in its outer core and produce the main field. Knowledge of whether the field is ergodic, i.e. whether time averages correspond to phase space averages, is an important question since, if this were true, it would point out a strong spatio-temporal coupling amongst the components of the dynamical system behind the present geomagnetic field generation. Another consequence would be that many computations, usually undertaken with many difficulties in the phase space, can be made in the conventional time domain. We analyse the temporal behaviour of the deviation between predictive and definitive geomagnetic global models for successive intervals from 1965 to 2010, finding a similar exponential growth with time. Also going back in time (at around 1600 and 1900 by using the GUFM1 model) confirms the same findings. This result corroborates previous chaotic analyses made in a reconstructed phase space from geomagnetic observatory time series, confirming the chaotic character of the recent geomagnetic field with no reliable prediction after around 6 years from definitive values, and disclosing the potentiality of estimating important entropic quantities of the field by time averages. Although more tests will be necessary, some of our analyses confirm the efforts to improve the representation of the geomagnetic field with more detailed secular variation and acceleration.

  5. Proterozoic low orbital obliquity and axial-dipolar geomagnetic field from evaporite palaeolatitudes.

    PubMed

    Evans, David A D

    2006-11-01

    Palaeomagnetism of climatically sensitive sedimentary rock types, such as glacial deposits and evaporites, can test the uniformitarianism of ancient geomagnetic fields and palaeoclimate zones. Proterozoic glacial deposits laid down in near-equatorial palaeomagnetic latitudes can be explained by 'snowball Earth' episodes, high orbital obliquity or markedly non-uniformitarian geomagnetic fields. Here I present a global palaeomagnetic compilation of the Earth's entire basin-scale evaporite record. Magnetic inclinations are consistent with low orbital obliquity and a geocentric-axial-dipole magnetic field for most of the past two billion years, and the snowball Earth hypothesis accordingly remains the most viable model for low-latitude Proterozoic ice ages. Efforts to reconstruct Proterozoic supercontinents are strengthened by this demonstration of a consistently axial and dipolar geomagnetic reference frame, which itself implies stability of geodynamo processes on billion-year timescales. PMID:17080082

  6. Proterozoic low orbital obliquity and axial-dipolar geomagnetic field from evaporite palaeolatitudes

    NASA Astrophysics Data System (ADS)

    Evans, David A. D.

    2006-11-01

    Palaeomagnetism of climatically sensitive sedimentary rock types, such as glacial deposits and evaporites, can test the uniformitarianism of ancient geomagnetic fields and palaeoclimate zones. Proterozoic glacial deposits laid down in near-equatorial palaeomagnetic latitudes can be explained by `snowball Earth' episodes, high orbital obliquity or markedly non-uniformitarian geomagnetic fields. Here I present a global palaeomagnetic compilation of the Earth's entire basin-scale evaporite record. Magnetic inclinations are consistent with low orbital obliquity and a geocentric-axial-dipole magnetic field for most of the past two billion years, and the snowball Earth hypothesis accordingly remains the most viable model for low-latitude Proterozoic ice ages. Efforts to reconstruct Proterozoic supercontinents are strengthened by this demonstration of a consistently axial and dipolar geomagnetic reference frame, which itself implies stability of geodynamo processes on billion-year timescales.

  7. Total Geomagnetic Survey on Suruga Bay, on the Pacific cost, Shizuoka, Japan

    NASA Astrophysics Data System (ADS)

    Baba, H.; Ishida, M.; Sakamoto, I.; Onishi, N.

    2012-12-01

    In 2009 to 2012, total geomagnetic and geological surveys by School of Marine Science & Technology, Tokai University, were conducted on Suruga Bay, located on the Pacific coast of Honshu in Shizuoka Prefecture, central Japan, where a large thrust earthquake, often referred to as the Tokai earthquake, has been supposed to occur soon (Ishibashi, 1981). Suruga Bay area, where the Philippine Sea plate subducts beneath Japan, had some local magnetic anomalies on the overriding plate side. The past investigation of ship-borne survey conducted in Suruga Bay area is geomagnetic anomaly data of the Hydrographic Department of the Maritime Safety Agency in 1997. Detailed geomagnetic surveys carried out in the Suruga Bay area, is 50 km x 35km in S-N and W-E, respectively. Total geomagnetic anomaly values range from +100nT to +600nT. We carried out 2.5d inversion analyses for some positive high anomalies to reveal the dimensions of anomalous body, assuming uniformly magnetization. We present features of total geomagnetic anomalies on and around Suruga Bay with the results of inversion.

  8. Total electron content variations observed at a low latitude GPS station in association to geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Mendes da Costa, A.; Fonseca Junior, E.; Vilas Boas, J.

    Total electron content (TEC) has been continuously monitored since January 1997, using a GPS dual frequency receiver located at Presidente Prudente (22o 07'S, 51o 22' W). In this paper the enhancements observed in the ionspheric TEC are associated with geomagnetic field variations for six geomagnetic storms that occurred from 1997 to 2000. The events were selected according to the integrity and availability of data. The purpose of this study is to provide a better knowledge of the low-latitude behavior of TEC in association to geomagnetic storms. Quiet-time TEC values were obtained by the average of the five magnetically less disturbed days of the month. These values were subtracted from the TEC hourly averages measured during the period of the magnetic storms. Magnetic field intensity measured on the ground was used for the identification of the storm time variations and the Dst indices were also included as a reference for the latitudes considered. The results showed that moderate geomagnetic storms produce small effects in TEC, intense and super intense (Dst < ~150 nT) geomagnetic storms produce well defined and long lasting TEC enhancements. The super intense storms cause the GPS signals to loose their track and the corresponding TEC values cannot be derived.

  9. On Geomagnetism and Paleomagnetism I

    NASA Technical Reports Server (NTRS)

    Voorhies, Coerte V.

    2000-01-01

    A partial description of Earth's broad scale, core-source magnetic field has been developed and tested three ways. The description features an expected, or mean, spatial magnetic power spectrum that is approximately inversely proportional to horizontal wavenumber atop Earth's core. This multipole spectrum describes a magnetic energy range; it is not steep enough for Gubbins' magnetic dissipation range. Temporal variations of core multipole powers about mean values are to be expected and are described statistically, via trial probability distribution functions, instead of deterministically, via trial solution of closed transport equations. The distributions considered here are closed and neither require nor prohibit magnetic isotropy. The description is therefore applicable to, and tested against, both dipole and low degree non-dipole fields. In Part 1, a physical basis for an expectation spectrum is developed and checked. The description is then combined with main field models of twentieth century satellite and surface geomagnetic field measurements to make testable predictions of the radius of Earth's core. The predicted core radius is 0.7% above the 3480 km seismological value. Partial descriptions of other planetary dipole fields are noted.

  10. Geomagnetic Field Modeling with DMSP

    NASA Astrophysics Data System (ADS)

    Alken, P.; Redmon, R. J.; Rich, F. J.; Maus, S.; Luhr, H.

    2013-12-01

    The Defense Meteorological Satellite Program (DMSP) launches and maintains a network of satellites to monitor the meteorological, oceanographic, and solar-terrestrial physics environments. In the past decade, geomagnetic field modelers have focused much attention on magnetic measurements from missions such as CHAMP, Oersted and SAC-C. With the completion of the CHAMP mission in 2010, there have been limited satellite-based vector and scalar magnetic field measurements available for main field modeling. In this study, we investigate the feasibility of using the Special Sensor Magnetometer (SSM) instrument onboard DMSP for main field modeling. These vector field measurements are calibrated to compute instrument timing shifts, scale factors, offsets, and non-orthogonalities in the fluxgate magnetometer cores. Euler angles are then computed to determine the orientation of the vector magnetometer with respect to a local coordinate system. We fit a degree 12 main field model to the dataset and compare with similar models such as the World Magnetic Model (WMM) and IGRF. Initial results indicate that the DMSP dataset will be a valuable source for main field modeling for the years between CHAMP and the upcoming Swarm mission.

  11. Advantage of wavelet technique to highlight the observed geomagnetic perturbations linked to the Chilean tsunami (2010)

    NASA Astrophysics Data System (ADS)

    Klausner, V.; Mendes, Odim; Domingues, Margarete O.; Papa, Andres R. R.; Tyler, Robert H.; Frick, Peter; Kherani, Esfhan A.

    2014-04-01

    The vertical component (Z) of the geomagnetic field observed by ground-based observatories of the International Real-Time Magnetic Observatory Network has been used to analyze the induced magnetic fields produced by the movement of a tsunami, electrically conducting sea water through the geomagnetic field. We focus on the survey of minutely sampled geomagnetic variations induced by the tsunami of 27 February 2010 at Easter Island (IPM) and Papeete (PPT) observatories. In order to detect the tsunami disturbances in the geomagnetic data, we used wavelet techniques. We have observed an 85% correlation between the Z component variation and the tide gauge measurements in period range of 10 to 30 min which may be due to two physical mechanisms: gravity waves and the electric currents in the sea. As an auxiliary tool to verify the disturbed magnetic fields, we used the maximum variance analysis (MVA). At PPT, the analyses show local magnetic variations associated with the tsunami arriving in advance of sea surface fluctuations by about 2 h. The first interpretation of the results suggests that wavelet techniques and MVA can be effectively used to characterize the tsunami contributions to the geomagnetic field and further used to calibrate tsunami models and implemented to real-time analysis for forecast tsunami scenarios.

  12. 12 CFR 204.125 - Foreign, international, and supranational entities referred to in §§ 204.2(c)(1)(iv)(E) and 204.8...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 2 2013-01-01 2013-01-01 false Foreign, international, and supranational entities referred to in §§ 204.2(c)(1)(iv)(E) and 204.8(a)(2)(i)(B)(5). 204.125 Section 204.125 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM RESERVE REQUIREMENTS OF DEPOSITORY INSTITUTIONS (REGULATION...

  13. Bats Use Geomagnetic Field: Behavior and Mechanism

    NASA Astrophysics Data System (ADS)

    Pan, Y.; Tian, L.; Zhang, B.; Zhu, R.

    2015-12-01

    It has been known that numerous animals can use the Earth's magnetic field for spatial orientation and long-distance navigation, nevertheless, how animals can respond to the magnetic field remain mostly ambiguous. The intensities of the global geomagnetic field varies between 23 and 66 μT, and the geomagnetic field intensity could drop to 10% during geomagnetic polarity reversals or geomagnetic excursions. Such dramatic changes of the geomagnetic field may pose a significant challenge for the evolution of magnetic compass in animals. For examples, it is vital whether the magnetic compass can still work in such very weak magnetic fields. Our previous experiment has demonstrated that a migratory bat (Nyctalus plancyi) uses a polarity compass for orientation during roosting when exposed to an artificial magnetic field (100 μT). Recently, we experimentally tested whether the N. plancyi can sense very weak magnetic fields that were even lower than those of the present-day geomagnetic field. Results showed: 1) the bats can sense the magnetic north in a field strength of present-day local geomagnetic field (51μT); 2) As the field intensity decreased to only 1/5th of the natural intensity (10 μT), the bats still responded by positioning themselves at the magnetic north. Notably, as the field polarity was artificially reversed, the bats still preferred the new magnetic north, even at the lowest field strength tested (10 μT). Hence, N. plancyi is able to detect the direction of a magnetic field with intensity range from twice to 1/5th of the present-day field strength. This allows them to orient themselves across the entire range of present-day global geomagnetic field strengths and sense very weak magnetic fields. We propose that this high sensitivity might have evolved in bats as the geomagnetic field strength varied and the polarity reversed tens of times over the past fifty million years since the origin of bats. The physiological mechanisms underlying

  14. Geomagnetic storm forecasts several hours ahead

    NASA Astrophysics Data System (ADS)

    Podladchikova, Tatiana; Petrukovich, Anatoli

    In this study we present a service implemented at Space Research Institute, Russia, providing an advance warning about the future geomagnetic storm magnitude (the negative peak Dst) using first geomagnetic storm indications. We demonstrate a clear relation between the solar wind parameters in the beginning of the storm development with the ultimate storm strength. For suddenly developing major storms that have essential influence on susceptible technological systems such as satellites, pipelines, power systems, and radio communications we predict lower and upper limits of the negative peak Dst. The high predictive potential of the proposed technique was confirmed by testing it on geomagnetic storms during the period 1995-2013. The advance warning time about the future geomagnetic storm strength on average achieves 5-6 hours and varies from 1 to 22 hours. The error of the peak Dst prediction does not exceed 25% with probability of 0.96. The false prediction probability does not exceed 0.03. Real-time predictions of the geomagnetic storm magnitude are updated every hour and published at http://spaceweather.ru

  15. The causes of recurrent geomagnetic storms

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Lepping, R. P.

    1976-01-01

    The causes of recurrent geomagnetic activity were studied by analyzing interplanetary magnetic field and plasma data from earth-orbiting spacecraft in the interval from November 1973 to February 1974. This interval included the start of two long sequences of geomagnetic activity and two corresponding corotating interplanetary streams. In general, the geomagnetic activity was related to an electric field which was due to two factors: (1) the ordered, mesoscale pattern of the stream itself, and (2) random, smaller-scale fluctuations in the southward component of the interplanetary magnetic field Bz. The geomagnetic activity in each recurrent sequence consisted of two successive stages. The first stage was usually the most intense, and it occurred during the passage of the interaction region at the front of a stream. These large amplitudes of Bz were primarily produced in the interplanetary medium by compression of ambient fluctuations as the stream steepened in transit to 1 A.U. The second stage of geomagnetic activity immediately following the first was associated with the highest speeds in the stream.

  16. Ionospheric redistribution during geomagnetic storms

    PubMed Central

    Immel, T J; Mannucci, A J

    2013-01-01

    [1]The abundance of plasma in the daytime ionosphere is often seen to grow greatly during geomagnetic storms. Recent reports suggest that the magnitude of the plasma density enhancement depends on the UT of storm onset. This possibility is investigated over a 7year period using global maps of ionospheric total electron content (TEC) produced at the Jet Propulsion Laboratory. The analysis confirms that the American sector exhibits, on average, larger storm time enhancement in ionospheric plasma content, up to 50% in the afternoon middle-latitude region and 30% in the vicinity of the high-latitude auroral cusp, with largest effect in the Southern Hemisphere. We investigate whether this effect is related to the magnitude of the causative magnetic storms. Using the same advanced Dst index employed to sort the TEC maps into quiet and active (Dst<−100 nT) sets, we find variation in storm strength that corresponds closely to the TEC variation but follows it by 3–6h. For this and other reasons detailed in this report, we conclude that the UT-dependent peak in storm time TEC is likely not related to the magnitude of external storm time forcing but more likely attributable to phenomena such as the low magnetic field in the South American region. The large Dst variation suggests a possible system-level effect of the observed variation in ionospheric storm response on the measured strength of the terrestrial ring current, possibly connected through UT-dependent modulation of ion outflow. PMID:26167429

  17. An introduction to quiet daily geomagnetic fields

    USGS Publications Warehouse

    Campbell, W.H.

    1989-01-01

    On days that are quiet with respect to solar-terrestrial activity phenomena, the geomagnetic field has variations, tens of gamma in size, with major spectral components at about 24, 12, 8, and 6 hr in period. These quiet daily field variations are primarily due to the dynamo currents flowing in the E region of the earth's ionosphere, are driven by the global thermotidal wind systems, and are dependent upon the local tensor conductivity and main geomagnetic field vector. The highlights of the behavior and interpretation of these quiet field changes, from their discovery in 1634 until the present, are discussed as an introduction to the special journal issue on Quiet Daily Geomagnetic Fields. ?? 1989 Birkha??user Verlag.

  18. Solar flares, flare particles and geomagnetic disturbances

    NASA Astrophysics Data System (ADS)

    Ogawa, T.

    1986-03-01

    Geomagnetic disturbances related to solar-terrestrial events during the period June-September 1982 are described. The cause of these activities is investigated using solar phenomena and solar flare particles observed by the geostationary satellite GMS-2/SEM (Space Environment Monitor). It is noted that the geomagnetic disturbances in June were weak, two big geomagnetic storms occurred in September, and the largest storm, caused by a large flare, occurred on July 13-14. The July 13-14, 1972 storm is compared to the February 11-12, 1958 storm observed by Hakura and Nagai (1964, 1965) and the August 4-5, 1972 storm data of Hakura (1976). The July storm was characterized by a deep depression of the H-component caused by an abnormal expansion of the substorm-associated current system in the auroral zone toward the Far East and was short-lived.

  19. Geomagnetic anomaly detected at hydromagnetic wave frequencies

    NASA Astrophysics Data System (ADS)

    Meloni, A.; Medford, L. V.; Lanzerotti, L. J.

    1985-04-01

    We report the discovery, in northwestern Illinois, of a geomagnetic anomaly, using hydromagnetic wave frequencies as the source spectrum. Three portable magnetometer stations with computer-compatible digital data acquisition systems were operated in a longitude array at Piano and Ashton, Illinois, and Cascade, Iowa (total separation ˜200 km), in 1981-1982. Analysis of the natural geomagnetic field fluctuations in the hydromagnetic wave regime reveals that the vertical components of the detected fluctuations are essentially 180° out of phase between Plano/Ashton and Cascade for variations with periods ˜30-120 s. The observations can be modeled in terms of a shallow (˜10-20 km) north-south oriented geomagnetic anomaly of enhanced conductivity located between Ashton and Cascade, approximately parallel to the Mississippi River valley.

  20. Scaling laws from geomagnetic time series

    USGS Publications Warehouse

    Voros, Z.; Kovacs, P.; Juhasz, A.; Kormendi, A.; Green, A.W.

    1998-01-01

    The notion of extended self-similarity (ESS) is applied here for the X - component time series of geomagnetic field fluctuations. Plotting nth order structure functions against the fourth order structure function we show that low-frequency geomagnetic fluctuations up to the order n = 10 follow the same scaling laws as MHD fluctuations in solar wind, however, for higher frequencies (f > l/5[h]) a clear departure from the expected universality is observed for n > 6. ESS does not allow to make an unambiguous statement about the non triviality of scaling laws in "geomagnetic" turbulence. However, we suggest to use higher order moments as promising diagnostic tools for mapping the contributions of various remote magnetospheric sources to local observatory data. Copyright 1998 by the American Geophysical Union.

  1. Geomagnetic storm forecasts and the power industry

    NASA Astrophysics Data System (ADS)

    Kappenman, John G.; Zanetti, Lawrence J.; Radasky, William A.

    There is a well-recognized link between solar activity, geomagnetic disturbances, and disruptions to man-made systems such as power grids, satellites, communications, and defense systems. As technology evolves, these systems become more susceptible to magnetic disturbances than their counterparts of previous solar cycles. Analysis suggests that these vulnerabilities will continue and perhaps even increase as these systems continue to evolve.Geomagnetic disturbances can cause geomagnetically induced currents (GIC) to flow through the power system, entering and exiting the many grounding points on a transmission network. This is generally of most concern at the latitudes of the northern United States, Canada, and Scandinavia, for example, but regions much farther south are also affected during intense magnetic storms.

  2. An Annotated Reference Guide on International Telecommunications and Transborder Data Flow for Library and Information Science Professionals.

    ERIC Educational Resources Information Center

    Borod, Elizabeth A.

    The purpose of this guide is to provide library and information professionals with a brief history of telecommunications and transborder data flow (TDF) as well as an annotated listing of available resources and organizations concerned with these topics. The bibliography is organized into 14 themes: (1) communication--international; (2)…

  3. Geomagnetic field changes in association with the 2011 Tohoku-Oki Earthquake and Tsunami

    NASA Astrophysics Data System (ADS)

    Utada, H.; Shimizu, H.; Ogawa, T.; Maeda, T.; Furumura, T.; Yamamoto, T.; Yamazaki, N.; Yoshitake, Y.; Nagamachi, S.

    2011-12-01

    Does the geomagnetic field change in association with or prior to Earthquakes? This question was first raised more than 100 years ago, and since that time, theoretical and observational research has been conducted in order to obtain an answer to this question. Large earthquakes provide an opportunity to examine this problem, because large signals are generally expected in association with large earthquakes. We herein present a preliminary report of simultaneous measurements of the geomagnetic field in association with the 2011 Tohoku Earthquake (M9.0) and Tsunami by magnetometers operating in Japan. Geomagnetic data sampled at every minute from 14 geomagnetic stations were collected, and the total intensity (from all stations) and three components (from stations available) from January 1 to March 22, 2011 were analyzed. Since the earthquake occurred during a geomagnetic storm, we used time series after correcting the effect of external disturbance and its induced fields by taking two horizontal components of KNY as a reference. A coseismic change of the geomagnetic total intensity was observed at several stations located relatively close to the epicenter. We did not estimate coseismic changes in the three component data, because of the presence of apparent offsets caused by strong quakes. The magnitude of this coseismic change in the total intensity was on the order of 1 nT or less, which is consistent with predictions based on piezomagnetic theory. More distinct and rapid changes were observed which started immediately after the main shock and continued for a few hours. Although the rapid change was observed in every component, the amplitude of declination change is the largest which started about 10 minutes after the main shock. Before this declination change, changes of a few nT in the vertical component and the total intensity were observed at stations close to the epicenter. The former change is supposed to be caused by the ionospheric disturbance, and the

  4. First geomagnetic measurements in the Antarctic region

    NASA Astrophysics Data System (ADS)

    Raspopov, O. M.; Demina, I. M.; Meshcheryakov, V. V.

    2014-05-01

    Based on data from literature and archival sources, we have further processed and analyzed the results of geomagnetic measurements made during the 1772-1775 Second World Expedition by James Cook and the 1819-1821 overseas Antarctic Expedition by Russian mariners Bellingshausen and Lazarev. Comparison with the GUFM historical model showed that there are systematic differences in the spatial structure of both the declination and its secular variation. The results obtained can serve as a basis for the construction of regional models of the geomagnetic field for the Antarctic region.

  5. Large Geomagnetic Storms: Introduction to Special Section

    NASA Technical Reports Server (NTRS)

    Gopalswamy, N.

    2010-01-01

    Solar cycle 23 witnessed the accumulation of rich data sets that reveal various aspects of geomagnetic storms in unprecedented detail both at the Sun where the storm causing disturbances originate and in geospace where the effects of the storms are directly felt. During two recent coordinated data analysis workshops (CDAWs) the large geomagnetic storms (Dst < or = -100 nT) of solar cycle 23 were studied in order to understand their solar, interplanetary, and geospace connections. This special section grew out of these CDAWs with additional contributions relevant to these storms. Here I provide a brief summary of the results presented in the special section.

  6. Satellite Data for Geomagnetic Field Modeling

    NASA Technical Reports Server (NTRS)

    Langel, R. A.; Baldwin, R. T.

    1992-01-01

    Satellite measurements of the geomagnetic fields began with the launch of Sputnik 3 in May of 1958 and have continued sporadically. Spacecraft making significant contributions to main field geomagnetism will be reviewed and the characteristics of their data discussed, including coverage, accuracy, resolution and data availability. Of particular interest are Vanguard 3; Cosmos 49, Ogo's -2, -4, and -6; Magsat; DE-2; and POGS. Spacecraft make measurements on a moving platfrom above the ionosphere as opposed to measurements from fixed observatories and surveys, both below the ionosphere. Possible future missions, such as Aristoteles and GOS are reviewed.

  7. Anencephalus, drinking water, geomagnetism and cosmic radiation.

    PubMed

    Archer, V E

    1979-01-01

    The mortality rates from anencephalus from 1950-1969 in Canadian cities are shown to be strongly correlated with city growth rate and with horizontal geomagnetic flux, which is directly related to the intensity of cosmic radiation. They are also shown to have some association with the magnesium content of drinking water. Prior work with these data which showed associations with magnesium in drinking water, mean income, latitude and longitude was found to be inadequate because it dismissed the observed geographic associations as having little biological meaning, and because the important variables of geomagnetism and city growth rate were overlooked. PMID:433919

  8. Tsunami related to solar and geomagnetic activity

    NASA Astrophysics Data System (ADS)

    Cataldi, Gabriele; Cataldi, Daniele; Straser, Valentino

    2016-04-01

    The authors of this study wanted to verify the existence of a correlation between earthquakes of high intensity capable of generating tsunami and variations of solar and Earth's geomagnetic activity. To confirming or not the presence of this kind of correlation, the authors analyzed the conditions of Spaceweather "near Earth" and the characteristics of the Earth's geomagnetic field in the hours that preceded the four earthquakes of high intensity that have generated tsunamis: 1) Japan M9 earthquake occurred on March 11, 2011 at 05:46 UTC; 2) Japan M7.1 earthquake occurred on October 25, 2013 at 17:10 UTC; 3) Chile M8.2 earthquake occurred on April 1, 2014 at 23:46 UTC; 4) Chile M8.3 earthquake occurred on September 16, 2015 at 22:54 UTC. The data relating to the four earthquakes were provided by the United States Geological Survey (USGS). The data on ion density used to realize the correlation study are represented by: solar wind ion density variation detected by ACE (Advanced Composition Explorer) Satellite, in orbit near the L1 Lagrange point, at 1.5 million of km from Earth, in direction of the Sun. The instrument used to perform the measurement of the solar wind ion density is the Electron, Proton, and Alpha Monitor (EPAM) instrument, equipped on the ACE Satellite. To conduct the study, the authors have taken in consideration the variation of the solar wind protons density of three different energy fractions: differential proton flux 1060-1900 keV (p/cm^2-sec-ster-MeV); differential proton flux 761-1220 keV (p/cm^2-sec-ster-MeV); differential proton flux 310-580 keV (p/cm^2-sec-ster-MeV). Geomagnetic activity data were provided by Tromsø Geomagnetic Observatory (TGO), Norway; by Scoresbysund Geomagnetic Observatory (SCO), Greenland, Denmark and by Space Weather Prediction Center of Pushkov Institute of terrestrial magnetism, ionosphere and radio wave propagation (IZMIRAN), Troitsk, Moscow Region. The results of the study, in agreement with what already

  9. Geomagnetic storm fields near a synchronous satellite.

    NASA Technical Reports Server (NTRS)

    Kawasaki, K.; Akasofu, S. I.

    1971-01-01

    An apparent early recovery of the main phase of geomagnetic storms at the distance of the synchronous satellite is examined in terms of changing electric current distributions in the magnetosphere during magnetic storms. It is suggested that a rapid recession of the edge of the plasma sheet (after the advance toward the earth during an early epoch of the main phase) is partly responsible for the early recovery. Relevant plasma sheet variations during geomagnetic storms are found to be in agreement with the inferred variations.

  10. A simple statistical model for geomagnetic reversals

    NASA Technical Reports Server (NTRS)

    Constable, Catherine

    1990-01-01

    The diversity of paleomagnetic records of geomagnetic reversals now available indicate that the field configuration during transitions cannot be adequately described by simple zonal or standing field models. A new model described here is based on statistical properties inferred from the present field and is capable of simulating field transitions like those observed. Some insight is obtained into what one can hope to learn from paleomagnetic records. In particular, it is crucial that the effects of smoothing in the remanence acquisition process be separated from true geomagnetic field behavior. This might enable us to determine the time constants associated with the dominant field configuration during a reversal.

  11. Internal Consistency and Associated Characteristics of Informant Discrepancies in Clinic Referred Youths Age 11 to 17 Years

    PubMed Central

    De Los Reyes, Andres; Youngstrom, Eric A.; Pabón, Shairy C.; Youngstrom, Jennifer K.; Feeny, Norah C.; Findling, Robert L.

    2011-01-01

    In this study, we examined the internal consistency of informant discrepancies in reports of youth behavior and emotional problems and their unique relations with youth, caregiver, and family characteristics. In a heterogeneous multisite clinic sample of 420 youths (ages 11 to 17 years), high internal consistency estimates were observed across measures of informant discrepancies. Further, latent profile analyses identified systematic patterns of discrepancies, characterized by their magnitude and direction (i.e., which informant reported greater youth problems). Additionally, informant discrepancies systematically and uniquely related to informants' own perspectives of youth mood problems, and these relations remained significant after taking into account multiple informants' reports of informant characteristics widely known to relate to informant discrepancies. These findings call into the question the prevailing view of informant discrepancies as indicative of unreliability and/or bias on the part of informants' reports of youths' behavior. PMID:21229442

  12. Variability of equatorial ionospheric anomaly at two stations during geomagnetic storms: observations and IRI 2012 predictions

    NASA Astrophysics Data System (ADS)

    Oyeyemi, Elijah; Bolaji, Olusegun; Olajide, Adewale; Akala, Andrew; Olugbon, Busola; Amaechi, Paul

    2016-07-01

    This paper discusses the variations of electron density of ionospheric F2-layer (NmF2) during geomagnetic storm periods using ionosonde observations from two ionospheric stations (Tahiti [geographic coordinates, 17.7oS, 210.1oE, magnetic coordinates, 15.2oS, 284.4oE] and Maui [geographic coordinates, 20.8oN, 203.5oE, magnetic coordinates, 21.2oN, 269.6oE]), in the region of equatorial ionization anomaly. We have used data, based on availability, corresponding to different seasonal and high solar activity periods (1979, 1980, 1989 and 1990) from each station to carry out our investigations. The results obtained from statistical analysis were used to evaluate the accuracy of the International Reference Ionosphere (IRI-2012) model predictions in this region. The results show that, generally, the IRI model predictions have agreement with the observed values in terms of the pattern of variations but there are number of cases where IRI model overestimates and underestimates the observed values. Results from this study will be of help to improving prediction ability of the IRI models. Details of the analysis of the accuracy of the IRI model predictions are presented.

  13. Determination of Geomagnetically Quiet Time Disturbances of the Ionosphere over Uganda during the Beginning of Solar Cycle

    NASA Astrophysics Data System (ADS)

    Habyarimana, Valence

    2016-07-01

    The ionosphere is prone to significant disturbances during geomagnetically active and quiet conditions. This study focused on the occurrence of ionospheric disturbances during geomagnetically quiet conditions. Ionospheric data comprised of Global Positioning System (GPS)-derived Total Electron Content (TEC), obtained over Mt. Baker, Entebbe, and Mbarara International Global Navigation Satellite System (GNSS) Service (IGS) stations. The Disturbance storm time (Dst) index was obtained from Kyoto University website. The number of geomagnetically quiet days in the period under study were first identified. Their monthly percentages were compared for the two years. The monthly percentage of geomagnetically quiet days for all the months in 2009 numerically exceeded those in 2008. December had the highest percentage of geomagnetically quiet days for both years (94 % in 2008 and 100 % in 2009). Geomagnetically quiet days did not show seasonal dependence. The variation in percentage of geomagnetically quiet days during solstice months (May, June, July, November, December, and January) and equinoctial months (February, March, April, August, September, and October) was not uniform. Geomagnetically quiet time disturbances were found to be more significant from 09:00 UT to 13:00 UT. However, there were some other disturbances of small scale amplitude that occurred between 14:00 UT and 22:00 UT. Further analysis was done to identify the satellites that observed the irregularities that were responsible for TEC perturbations. Satellites are identified by Pseudo Random Numbers (PRNs). The ray path between individual PRNs and the corresponding receivers were analysed. Satellites with PRNs: 3, 7, 8, 19 and 21 registered most of the perturbations. It was found that Q disturbances led to fluctuations in density gradients. Significant TEC perturbations were observed on satellite with PRN 21 with receivers at Entebbe and Mbarara on June 28, 2009 between 18:00 UT and 21:00 UT.

  14. Docking Offset Between the Space Shuttle and the International Space Station and Resulting Impacts to the Transfer of Attitude Reference and Control

    NASA Technical Reports Server (NTRS)

    Helms, W. Jason; Pohlkamp, Kara M.

    2011-01-01

    The Space Shuttle does not dock at an exact 90 degrees to the International Space Station (ISS) x-body axis. This offset from 90 degrees, along with error sources within their respective attitude knowledge, causes the two vehicles to never completely agree on their attitude, even though they operate as a single, mated stack while docked. The docking offset can be measured in flight when both vehicles have good attitude reference and is a critical component in calculations to transfer attitude reference from one vehicle to another. This paper will describe how the docking offset and attitude reference errors between both vehicles are measured and how this information would be used to recover Shuttle attitude reference from ISS in the event of multiple failures. During STS-117, ISS on-board Guidance, Navigation and Control (GNC) computers began having problems and after several continuous restarts, the systems failed. The failure took the ability for ISS to maintain attitude knowledge. This paper will also demonstrate how with knowledge of the docking offset, the contingency procedure to recover Shuttle attitude reference from ISS was reversed in order to provide ISS an attitude reference from Shuttle. Finally, this paper will show how knowledge of the docking offset can be used to speed up attitude control handovers from Shuttle to ISS momentum management. By taking into account the docking offset, Shuttle can be commanded to hold a more precise attitude which better agrees with the ISS commanded attitude such that start up transients with the ISS momentum management controllers are reduced. By reducing start-up transients, attitude control can be transferred from Shuttle to ISS without the use of ISS thrusters saving precious on-board propellant, crew time and minimizing loads placed upon the mated stack.

  15. Generation and Characterization of Six Recombinant Botulinum Neurotoxins as Reference Material to Serve in an International Proficiency Test.

    PubMed

    Weisemann, Jasmin; Krez, Nadja; Fiebig, Uwe; Worbs, Sylvia; Skiba, Martin; Endermann, Tanja; Dorner, Martin B; Bergström, Tomas; Muñoz, Amalia; Zegers, Ingrid; Müller, Christian; Jenkinson, Stephen P; Avondet, Marc-Andre; Delbrassinne, Laurence; Denayer, Sarah; Zeleny, Reinhard; Schimmel, Heinz; Åstot, Crister; Dorner, Brigitte G; Rummel, Andreas

    2015-12-01

    The detection and identification of botulinum neurotoxins (BoNT) is complex due to the existence of seven serotypes, derived mosaic toxins and more than 40 subtypes. Expert laboratories currently use different technical approaches to detect, identify and quantify BoNT, but due to the lack of (certified) reference materials, analytical results can hardly be compared. In this study, the six BoNT/A1-F1 prototypes were successfully produced by recombinant techniques, facilitating handling, as well as improving purity, yield, reproducibility and biosafety. All six BoNTs were quantitatively nicked into active di-chain toxins linked by a disulfide bridge. The materials were thoroughly characterized with respect to purity, identity, protein concentration, catalytic and biological activities. For BoNT/A₁, B₁ and E₁, serotypes pathogenic to humans, the catalytic activity and the precise protein concentration were determined by Endopep-mass spectrometry and validated amino acid analysis, respectively. In addition, BoNT/A₁, B₁, E₁ and F₁ were successfully detected by immunological assays, unambiguously identified by mass spectrometric-based methods, and their specific activities were assigned by the mouse LD50 bioassay. The potencies of all six BoNT/A1-F1 were quantified by the ex vivo mouse phrenic nerve hemidiaphragm assay, allowing a direct comparison. In conclusion, highly pure recombinant BoNT reference materials were produced, thoroughly characterized and employed as spiking material in a worldwide BoNT proficiency test organized by the EQuATox consortium. PMID:26703728

  16. Nonlinear Behavior of the Geomagnetic Fluctuations Recorded in Different Geomagnetic Latitudes

    NASA Astrophysics Data System (ADS)

    Kovacs, P.; Heilig, B.; Koppan, A.; Vadasz, G.; Echim, M.

    2014-12-01

    The paper concerns with the nonlinear properties of geomagnetic variations recorded in different geomagnetic latitudes, in the years of solar maximum and minimum. For the study, we use the geomagnetic time-series recorded by some of the stations of the EMMA quasi-meridional magnetometer network, established for pulsation study, in September 2001. The stations are located approx. along the magnetic meridian of 100 degree, and the sampling frequency of the series is 1 Hz. It is argued that the geomagnetic field exhibits nonlinear intermittent fluctuations in certain temporal scale range. For quantitatively investigating the scaling ranges and the variation of intermittent properties with latitude and time, we analyse the higher order moments of the time records (probability density function or structure function analyses). The multifractal or self-similar scaling of the fluctuations is investigated via the fitting of the P model to structure function scaling exponents. We also study the power-law behaviour of the power-spectral density functions of the series in order to evaluate the possible inertial frequency (and temporal) range of the geomagnetic field and compare them with the scaling ranges of structure functions. The range where intermittent geomagnetic variation is found falls typically between 100 and 20.000 s, i.e. covers the temporal range of the main phases of geomagnetic storms. It is shown that the intensity of intermittent fluctuations increases from solar minimum to solar maximum. The expected increase in the level of intermittency with the geomagnetic latitude can be evidenced only in the years of solar minimum. The research leading to these results has received funding from the European Community's Seventh Framework Programme ([FP7/2007-2013]) under grant agreement n° 313038/STORM.

  17. Indian Institute of Geomagnetism: Progress in research

    NASA Astrophysics Data System (ADS)

    Progress and aspects is the study of the geomagnetic variations in the Indian region on quiet and disturbed days, equatorial electrojet field, electromagnetic induction in the earth, magnetic pulsations, aeronomy, radio scintillations, magnetosphere and solar wind, and solar-terrestrial relationships were reported.

  18. Geomagnetic referencing in the arctic environment

    USGS Publications Warehouse

    Podjono, Benny; Beck, Nathan; Buchanan, Andrew; Brink, Jason; Longo, Joseph; Finn, Carol A.; Worthington, E. William

    2011-01-01

    Geomagnetic referencing is becoming an increasingly attractive alternative to north-seeking gyroscopic surveys to achieve the precise wellbore positioning essential for success in today's complex drilling programs. However, the greater magnitude of variations in the geomagnetic environment at higher latitudes makes the application of geomagnetic referencing in those areas more challenging. Precise, real-time data on those variations from relatively nearby magnetic observatories can be crucial to achieving the required accuracy, but constructing and operating an observatory in these often harsh environments poses a number of significant challenges. Operational since March 2010, the Deadhorse Magnetic Observatory (DED), located in Deadhorse, Alaska, was created through collaboration between the United States Geological Survey (USGS) and a leading oilfield services supply company. DED was designed to produce real-time geomagnetic data at the required level of accuracy, and to do so reliably under the extreme temperatures and harsh weather conditions often experienced in the area. The observatory will serve a number of key scientific communities as well as the oilfield drilling industry, and has already played a vital role in the success of several commercial ventures in the area, providing essential, accurate data while offering significant cost and time savings, compared with traditional surveying techniques.

  19. Geomagnetic referencing in the arctic environment

    USGS Publications Warehouse

    Poedjono, B.; Beck, N.; Buchanan, A. C.; Brink, J.; Longo, J.; Finn, C.A.; Worthington, E.W.

    2011-01-01

    Geomagnetic referencing is becoming an increasingly attractive alternative to north-seeking gyroscopic surveys to achieve the precise wellbore positioning essential for success in today's complex drilling programs. However, the greater magnitude of variations in the geomagnetic environment at higher latitudes makes the application of geomagnetic referencing in those areas more challenging. Precise, real-time data on those variations from relatively nearby magnetic observatories can be crucial to achieving the required accuracy, but constructing and operating an observatory in these often harsh environments poses a number of significant challenges. Operational since March 2010, the Deadhorse Magnetic Observatory (DED), located in Deadhorse, Alaska, was created through collaboration between the United States Geological Survey (USGS) and a leading oilfield services supply company. DED was designed to produce real-time geomagnetic data at the required level of accuracy, and to do so reliably under the extreme temperatures and harsh weather conditions often experienced in the area. The observatory will serve a number of key scientific communities as well as the oilfield drilling industry, and has already played a vital role in the success of several commercial ventures in the area, providing essential, accurate data while offering significant cost and time savings, compared with traditional surveying techniques. Copyright 2011, Society of Petroleum Engineers.

  20. Geomagnetic storms: historical perspective to modern view

    NASA Astrophysics Data System (ADS)

    Lakhina, Gurbax S.; Tsurutani, Bruce T.

    2016-12-01

    The history of geomagnetism is more than 400 years old. Geomagnetic storms as we know them were discovered about 210 years ago. There has been keen interest in understanding Sun-Earth connection events, such as solar flares, CMEs, and concomitant magnetic storms in recent times. Magnetic storms are the most important component of space weather effects on Earth. We give an overview of the historical aspects of geomagnetic storms and the progress made during the past two centuries. Super magnetic storms can cause life-threatening power outages and satellite damage, communication failures and navigational problems. The data for such super magnetic storms that occurred in the last 50 years during the space era is sparce. Research on historical geomagnetic storms can help to create a database for intense and super magnetic storms. New knowledge of interplanetary and solar causes of magnetic storms gained from spaceage observations will be used to review the super magnetic storm of September 1-2, 1859. We discuss the occurrence probability of such super magnetic storms, and the maximum possible intensity for the effects of a perfect ICME: extreme super magnetic storm, extreme magnetospheric compression, and extreme magnetospheric electric fields.

  1. Helio-geomagnetic influence in cardiological cases

    NASA Astrophysics Data System (ADS)

    Katsavrias, Ch.; Preka-Papadema, P.; Moussas, X.; Apostolou, Th.; Theodoropoulou, A.; Papadima, Th.

    2013-01-01

    The effects of the energetic phenomena of the Sun, flares and coronal mass ejections (CMEs) on the Earth's ionosphere-magnetosphere, through the solar wind, are the sources of the geomagnetic disturbances and storms collectively known as Space Weather. The research on the influence of Space Weather on biological and physiological systems is open. In this work we study the Space Weather impact on Acute Coronary Syndromes (ACS) distinguishing between ST-segment elevation acute coronary syndromes (STE-ACS) and non-ST-segment elevation acute coronary syndromes (NSTE-ACS) cases. We compare detailed patient records from the 2nd Cardiologic Department of the General Hospital of Nicaea (Piraeus, Greece) with characteristics of geomagnetic storms (DST), solar wind speed and statistics of flares and CMEs which cover the entire solar cycle 23 (1997-2007). Our results indicate a relationship of ACS to helio-geomagnetic activity as the maximum of the ACS cases follows closely the maximum of the solar cycle. Furthermore, within very active periods, the ratio NSTE-ACS to STE-ACS, which is almost constant during periods of low to medium activity, changes favouring the NSTE-ACS. Most of the ACS cases exhibit a high degree of association with the recovery phase of the geomagnetic storms; a smaller, yet significant, part was found associated with periods of fast solar wind without a storm.

  2. Earthquake waves and the geomagnetic dynamo.

    PubMed

    Mullan, D J

    1973-08-10

    It is proposed that earthquake waves energize the geomagnetic dynamo. Fluid motions generated by earthquakes may have enough energy to be in equipartition with fields as large as 100 gauss. Seismic waves from meteoritic impacts with energies sufficient to reverse the field occur every 170,000 years. PMID:17777805

  3. Enhancing model based forecasting of geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Webb, Alla G.

    Modern society is increasingly dependent on the smooth operation of large scale technology supporting Earth based activities such as communication, electricity distribution, and navigation. This technology is potentially threatened by global geomagnetic storms, which are caused by the impact of plasma ejected from the Sun upon the protective magnetic field that surrounds the Earth. Forecasting the timing and magnitude of these geomagnetic storms is part of the emerging discipline of space weather. The most severe geomagnetic storms are caused by magnetic clouds, whose properties and characteristics are important variables in space weather forecasting systems. The methodology presented here is the development of a new statistical approach to characterize the physical properties (variables) of the magnetic clouds and to examine the extent to which theoretical models can be used in describing both of these physical properties, as well as their evolution in space and time. Since space weather forecasting is a complex system, a systems engineering approach is used to perform analysis, validation, and verification of the magnetic cloud models (subsystem of the forecasting system) using a model-based methodology. This research demonstrates that in order to validate magnetic cloud models, it is important to categorize the data by physical parameters such as velocity and distance travelled. This understanding will improve the modeling accuracy of magnetic clouds in space weather forecasting systems and hence increase forecasting accuracy of geomagnetic storms and their impact on earth systems.

  4. Generation and Characterization of Six Recombinant Botulinum Neurotoxins as Reference Material to Serve in an International Proficiency Test

    PubMed Central

    Weisemann, Jasmin; Krez, Nadja; Fiebig, Uwe; Worbs, Sylvia; Skiba, Martin; Endermann, Tanja; Dorner, Martin B.; Bergström, Tomas; Muñoz, Amalia; Zegers, Ingrid; Müller, Christian; Jenkinson, Stephen P.; Avondet, Marc-Andre; Delbrassinne, Laurence; Denayer, Sarah; Zeleny, Reinhard; Schimmel, Heinz; Åstot, Crister; Dorner, Brigitte G.; Rummel, Andreas

    2015-01-01

    The detection and identification of botulinum neurotoxins (BoNT) is complex due to the existence of seven serotypes, derived mosaic toxins and more than 40 subtypes. Expert laboratories currently use different technical approaches to detect, identify and quantify BoNT, but due to the lack of (certified) reference materials, analytical results can hardly be compared. In this study, the six BoNT/A1–F1 prototypes were successfully produced by recombinant techniques, facilitating handling, as well as improving purity, yield, reproducibility and biosafety. All six BoNTs were quantitatively nicked into active di-chain toxins linked by a disulfide bridge. The materials were thoroughly characterized with respect to purity, identity, protein concentration, catalytic and biological activities. For BoNT/A1, B1 and E1, serotypes pathogenic to humans, the catalytic activity and the precise protein concentration were determined by Endopep-mass spectrometry and validated amino acid analysis, respectively. In addition, BoNT/A1, B1, E1 and F1 were successfully detected by immunological assays, unambiguously identified by mass spectrometric-based methods, and their specific activities were assigned by the mouse LD50 bioassay. The potencies of all six BoNT/A1–F1 were quantified by the ex vivo mouse phrenic nerve hemidiaphragm assay, allowing a direct comparison. In conclusion, highly pure recombinant BoNT reference materials were produced, thoroughly characterized and employed as spiking material in a worldwide BoNT proficiency test organized by the EQuATox consortium. PMID:26703728

  5. Experimental investigation of possible geomagnetic feedback from energetic (0.1 to 16 keV) terrestrial O(+) ions in the magnetotail current sheet

    NASA Technical Reports Server (NTRS)

    Lennartsson, O. W.; Klumpar, D. M.; Shelley, E. G.; Quinn, J. M.

    1993-01-01

    Data from energetic ion mass spectrometers on the International Sun Earth Explorer 1 (ISEE 1) and AMPTE/CCE spacecraft are combined with geomagnetic and solar indices to investigate, in a statistical fashion, whether energized O(+) ions of terrestrial origin constitute a source of feedback which triggers or amplifies geomagnetic magnetotail current sheet. The ISSE 1 data (0.1-16 keV/e) provide in situ observations of the O(+) solar cycle 21, as well as inner magnetosphere data from same period. The CCE data (0.1-17 keV/e), taken during the subsequent solar minimum, all within 9 R(sub E), provide a reference for long-term variations in the magnetosphere O(+) content. Statistical correlations between the ion data and the indices, and between different indices, all point in the same direction: there is probably no feedback specific to the O(+) ions, in spite of the fact that they often contribute most of the ion mass density in the tail current sheet.

  6. Product definition for healthcare contracting: an overview of approaches to measuring hospital output with reference to the UK internal market.

    PubMed Central

    Söderlund, N

    1994-01-01

    OBJECTIVE--In many industrialised countries, health care third party payers are moving towards contracted provision arrangements with suppliers of hospital care. Essential to such a process is a standard approach to quantifying the care provided. This paper aims to outline the possible approaches to hospital product definition for the UK National Health Service, and recommends appropriate further research. METHODS--All published and unpublished studies on hospital output measurement in the NHS since 1980 were sought for the purposes of the review. This included both discursive and empirical work, and no exclusion criteria were applied. Most empirical reports on this topic, however, come from the United States. Consequently, the published reports since 1980 from the USA, accessed from the Medline and Healthplan CD-ROM databases, have also been included in the overview. CONCLUSIONS--Where data are sufficient, the true casemix approach offers advantages over other methods of output measurement. In the UK NHS, two systems--diagnosis-related groups (DRGs) and healthcare resource groups (HRGs)--are the only casemix measures that have achieved any significant degree of attention. DRGs have been extensively evaluated internationally, and explain variations in resource use in the UK slightly better than do HRGs. As a local product, HRGs can be more easily adapted to the specific needs of the NHS internal market, however, and will thus probably emerge as a better measure for the UK in the long term. In both cases, locally derived cost weights are unavailable, and their development constitutes a major requirement for use in contracting. Adaptations for long stay and outpatient hospital episodes would enhance the usefulness of hospital casemix systems in the NHS. Existing approaches, such as specialty based classifications, are neither standardised nor predictive of resource use, and would be better replaced by casemix systems. Other countries facing similar choices between

  7. The geomagnetic storms of 2015: Statistical analysis and forecasting results

    NASA Astrophysics Data System (ADS)

    Paouris, Evangelos; Gerontidou, Maria; Mavromichalaki, Helen

    2016-04-01

    The year 2015 was characterized by long geomagnetic quiet periods with a lot of geomagnetically active breaks although it is on the declining phase of the current solar cycle. As a result a number of geomagnetic storms in the G1 up to G4 scale were noticed. In this work the characteristics of these geomagnetic storms like the scale level, the origin of the storm (CME or CIR) and the duration have been studied. Furthermore, a statistical analysis of these events and a comparative study of the forecasting and the actual geomagnetic conditions are performed using data from the NOAA space weather forecasting center and from the Athens Space Weather Forecasting Center as well. These forecasting centers estimate and provide every day the geomagnetic conditions for the upcoming days giving the values of the geomagnetic index Ap. The forecasting values of Ap index for the year 2015 from these two centers and their comparison in terms of the actual values are discussed.

  8. Aurora Boundaries Quantified by Geomagnetic Index

    NASA Astrophysics Data System (ADS)

    Carbary, J. F.

    2004-12-01

    Various operational systems require information on the location and intensity of the aurora. A statistical model of the aurora is given using global images from the Ultraviolet Imager (UVI) on the Polar satellite. The equatorward (EQ), poleward (PO) and peak (PK) boundaries of the auroral oval are determined. using UVI images averaged into 1° x1° spatial bins according to common geomagnetic indices such as Kp, AE, AL, and PCI. From these bin-averaged images, latitude intensity profiles at 1 hour MLT intervals are constructed by interpolation. A background is subtracted for each profile, and the EQ, PO, and PK boundary latitudes are found from the corrected profile. (The PK boundary is the maximum, and the EQ and PO boundaries are threshold locations of fixed irradiances such as 1, 2, or 4 photons/cm2s.) Several months of images during the winter and summer of 1997 were used to statistically quantify the boundaries at various levels of geomagnetic activity given by the several indices. As expected, the higher the level of activity, the wider and more expanded the oval. More importantly, the boundaries are functionally related to the indices at any local time. These functional relations can then be used to determine the auroral location at any level of geomagnetic activity given by the indices. Thus, given a level of geomagnetic activity, one can find the boundaries of the oval as defined on the basis of intensity. By monitoring the relevant geomagnetic index, an operational system can then easily compute the expected oval location and judge its impact on performance. The optimum indices that best define the oval will be discussed.

  9. What causes geomagnetic activity during sunspot minimum?

    NASA Astrophysics Data System (ADS)

    Kirov, B.; Asenovski, S.; Georgieva, K.; Obridko, V. N.

    2015-12-01

    It is well known that the main drivers of geomagnetic disturbances are coronal mass ejections whose number and intensity are maximum in sunspot maximum, and high speed solar wind streams from low latitude solar coronal holes which maximize during sunspot declining phase. But even during sunspot minimum periods when there are no coronal mass ejections and no low latitude solar coronal holes, there is some "floor" below which geomagnetic activity never falls. Moreover, this floor changes from cycle to cycle. Here we analyze the factors determining geomagnetic activity during sunspot minimum. It is generally accepted that the main factor is the thickness of the heliospheric current sheet on which the portion of time depends which the Earth spends in the slow and dense heliospheric current sheet compared to the portion of time it spends in the fast solar wind from superradially expanding polar coronal holes. We find, however, that though the time with fast solar wind has been increasing in the last four sunspot minima, the geomagnetic activity in minima has been decreasing. The reason is that the parameters of the fast solar wind from solar coronal holes change from minimum to minimum, and the most important parameter for the fast solar wind's geoeffectivity—its dynamic pressure—has been decreasing since cycle 21. Additionally, we find that the parameters of the slow solar wind from the heliospheric current sheet which is an important driver of geomagnetic activity in sunspot minimum also change from cycle to cycle, and its magnetic field, velocity and dynamic pressure have been decreasing during the last four minima.

  10. Carcinogenicity of trace elements with reference to evaluations made by the International Agency for Research on Cancer.

    PubMed

    Boffetta, P

    1993-01-01

    The monograph program of the International Agency for Research of on Cancer has evaluated many trace elements for their carcinogenicity to humans. Five groups of compounds were considered human carcinogens: arsenic and arsenic compounds, beryllium and beryllium compounds, cadmium and cadmium compounds, hexavalent chromium compounds, and nickel compounds. Antimony trioxide, cobalt and cobalt compounds, lead and inorganic lead compounds, methylmercury compounds, and metallic nickel were considered possibly carcinogenic to humans. Antimony trisulfide, trivalent chromium compounds, metallic chromium, ferric oxide, organolead compounds, metallic mercury, inorganic mercury compounds, selenium and selenium compounds, and titanium dioxide were not classifiable. Trace elements studied to a limited extent include copper, manganese, tin, vanadium, and zinc. Among the problems are the lack of relevant data, the definition of active species, the extrapolation of the results of experimental studies to humans, the methodological problems of epidemiologic studies, and the possible anticarcinogenic activity of some trace elements. PMID:8159977

  11. Reference dosimetry measurements for the international intercomparison of criticality accident dosimetry SILENE 9-21 June 2002.

    PubMed

    Asselineau, B; Trompier, F; Texier, C; Itié, C; Médioni, R; Tikunov, D; Muller, H; Pelcot, G

    2004-01-01

    An international intercomparison of criticality accident dosimetry systems took place in the SILENE reactor, in June 2002. Participants from 60 laboratories irradiated their dosemeters (physical and biological) using two different configurations of the reactor. In preparation for this intercomparison, the leakage radiation fields were characterised by spectrometry and dosimetry measurements using the ROSPEC spectrometer associated with a NE-213 scintillator, ionisation chambers, GM counters, diodes and thermoluminescence dosemeters (TLDs). For this intercomparison, a large area was required to irradiate the dosemeters both in free air and on phantoms. Therefore, measurements of the uniformity of the field were performed with activation detectors and TLDs for neutron and gammas, respectively. This paper describes the procedures used and the results obtained. PMID:15353691

  12. Ionospheric E-Region Response to Solar-Geomagnetic Storms Observed by TIMED/SABER and Application to IRI Storm-Model Development

    NASA Technical Reports Server (NTRS)

    Mertens, Christopher J.; Mast, Jeffrey C.; Winick, Jeremy R.; Russell, James M., III; Mlynczak, Martin G.; Evans, David S.

    2007-01-01

    The large thermospheric infrared radiance enhancements observed from the TIMED/SABER experiment during recent solar storms provide an exciting opportunity to study the influence of solar-geomagnetic disturbances on the upper atmosphere and ionosphere. In particular, nighttime enhancements of 4.3 um emission, due to vibrational excitation and radiative emission by NO+, provide an excellent proxy to study and analyze the response of the ionospheric E-region to auroral electron dosing and storm-time enhancements to the E-region electron density. In this paper we give a status report of on-going work on model and data analysis methodologies of deriving NO+ 4.3 um volume emission rates, a proxy for the storm-time E-region response, and the approach for deriving an empirical storm-time correction to International Reference Ionosphere (IRI) E-region NO+ and electron densities.

  13. Influence of precipitating energetic ions caused by EMIC waves on the subauroral ionospheric E region during a geomagnetic storm

    NASA Astrophysics Data System (ADS)

    Yuan, Zhigang; Xiong, Ying; Li, Haimeng; Huang, Shiyong; Qiao, Zheng; Wang, Zhenzhen; Zhou, Meng; Wang, Dedong; Deng, Xiaohua; Raita, Tero; Wang, Jingfang

    2014-10-01

    In this paper, we have presented the influence of precipitating energetic ions caused by electromagnetic ion cyclotron (EMIC) waves on the subauroral ionospheric E region during a geomagnetic storm on 8 March 2008 with observations of the Meteorological Operational (METOP-02) of the Polar Orbiting Environmental Satellites (POES), a GPS receiver in Vaasa of Finland and Finnish network of search coil magnetometers. Conjugate observations of the POES METOP-02 satellite and Finnish network of search coil magnetometers have demonstrated that enhancements of the precipitating energetic ion flux within the proton anisotropic zone are attributed to the interaction between ring current (RC) ions and EMIC waves. With enhancements of the intensity of Pc1 waves observed by search coil magnetometers, the total electron content observed by the GPS receiver accordingly increased, meaning that the enhancement of the ionospheric electron density is attributed to the precipitation of RC ions caused by EMIC waves. The electron density profiles derived by the International Reference Ionosphere (IRI-2007) model and with precipitating energetic protons observed by the POES METOP-02 satellite show that the energetic proton precipitation can cause the E layer peak electron density to increase from 1.62 × 109 m-3 to 5.05 × 1011 m-3 by 2.49 orders of magnitude. In comparison with the height-integrated conductivities derived by the IRI-2007 model, the height-integrated Pedersen and Hall conductivities derived with precipitating energetic protons increase by 2.4 and 2.34 orders of magnitude, respectively. Our result suggests that precipitating energetic ions caused by EMIC waves can lead to an obvious enhancement of the electron density and conductivities in the subauroral ionospheric E region during geomagnetic storms.

  14. Global matrix of thermospheric density values for selected solar/geomagnetic conditions and spacecraft orbital attitudes

    NASA Technical Reports Server (NTRS)

    Johnson, D. L.

    1984-01-01

    Presented are selected thermospheric/exospheric global mean and extreme density values computed between 130 and 1100 km altitude. These values were generated from the MSFC/J70 reference orbital atmospheric model using different input conditions of solar flux and geomagnetic index, ranging from low to peak. Typical magnitudes of day-night density changes are presented, as an example, for use in space vehicle orbital analyses.

  15. A Study on local geomagnetic activity trend and singularity with geomagnetic data at Cheongyang Magnetic Observatory, Korea

    NASA Astrophysics Data System (ADS)

    Lee, Y.; Jeon, Y.; Ryoo, S.

    2011-12-01

    The KMA(Korea Meteorological Administration) has installed and operated the geomagnetic observatory at Cheongyang-gun, Chungcheongnam-do, Korea which started in April, 2009. As Cheongyang geomagnetic observatory, it has been automatically observing total-, X-, Y- and Z-component data at 1-sec interval and storing in real-time. The National Institute of Meteorological Research, which belongs to KMA, proceeded with their work on the production of K-index that is used for geomagnetic activity observation. In addition, we detect the starting and ending of geomagnetic storm as typical thing of global geomagnetic field change and utilize it for showing current status of geomagnetic storm occurrence. It has been reported that geomagnetic storm occurred seven times during from April, 2010 to July, 2011. It was 5 of the maximum K-index value during geomagnetic storm occurrence period and thought mostly to have been caused by coronal hole and CME(Coronal Mass Ejection). Yet the geomagnetic storm has not been had much of an impact locally. At Cheongyang Observatory, a significantly disturbed geomagnetic data was seen as related to the Tohoku, Japan Earthquake, Mw 9.0, on March 11, 2011. Compared to seismic wave data at Seosan seismic observatory 60km away from Cheongyang geomagnetic observatory, we identified the signal involved to the Tohoku, Japan Earthquake. The power spectral density of the disturbed signal has the dominant frequency band of about 0.05 to 0.1 Hz. We should proceed additional study about this in detail.

  16. International organization for standardization (ISO) 9000 and chemical agent standard analytical reference material (SASARM) quality system development and implementation. Phase 1. Final report, April 1993-June 1994

    SciTech Connect

    Turley, S.D.

    1994-09-01

    U.S. Army Dugway Proving Ground (DPG) is in the process of developing an International Organization for Standardization (ISO) 9000 quality assurance (QA) system and a Chemical Agent Standard Analytical Reference Material (CASARM) QA program. Phase I of this process consisted of analyzing the current DPG QA system, defining the structure of the new QA system, determine how the ISO 9000 and the CASARM systems will interact, develop the new QA system and implementation plan, and develop the CASARM program and begin implementation. The initial phases of the system design and synthesis met the objectives established for Phase I of this methodology project. Phase II will complete the functional analysis, system design, and prototype implementation. The prototype will be analyzed for weaknesses in operation, personnel and equipment requirements, software, and cost effectiveness. The system will be modified, if needed, and implemented across the Materiel Test Directorate. The final stage of this methodology will be to achieve ISO 9000 registration. International Organization for Standardization(ISO) 9000, Chemical Agent Standard Analytical Reference Material(CASARM), Standardized Quality Assurance(QA), QA/Quality Control(QC).

  17. Mental Health and Its Associated Variables Among International Students at a Japanese University: With Special Reference to Their Financial Status.

    PubMed

    Kono, Kumi; Eskandarieh, Sharareh; Obayashi, Yoshihide; Arai, Asuna; Tamashiro, Hiko

    2015-12-01

    We attempted to identify the risk factors that may affect mental health status of the international students and we conducted the survey using a self-administered questionnaire. Depressive symptoms were measured using the Center for Epidemiologic Studies Depression Scale. The students were divided into two groups; (1) those who received scholarships and (2) those who didn't since we thought the division represented practical patterns of their financial status. The associations of socio-demographic characteristics with depressive symptoms were examined. Of the 726 students, 480 (66.1%) responded and 207 (43.1%) had depressive symptoms. The logistic regression analysis indicated that quality of sleep, amount of exercise, and housing conditions--but not financial status--were statistically associated with the risk of developing depressive symptoms. Although the inversion of the cause and effect is yet to be ascertained, the students who are unsatisfied with their housing conditions, quality of sleep and less exercise need more attention. PMID:25225076

  18. Characteristics of Older Adults Admitted to Hospital versus Those Discharged Home, in Emergency Department Patients Referred to Internal Medicine

    PubMed Central

    Hominick, Kathryn; McLeod, Victoria; Rockwood, Kenneth

    2016-01-01

    Background Frail older adults present to the Emergency Department (ED) with complex medical, functional, and social needs. When these needs can be addressed promptly, discharge is possible, and when they cannot, hospital admission is required. We evaluated the care needs of frail older adults in the ED who were consulted to internal medicine and seen by a geriatrician to determine, under current practices, which factors were associated with hospitalization and which allowed discharge. Methods We preformed a chart-based, exploratory study. Data were abstracted from consultation records and ED charts. All cases had a standard Comprehensive Geriatric Assessment (CGA which records a Clinical Frailty Scale (CFA) and allows calculation of a Frailty Index (FI). Results Of 100 consecutive patients, 2 died in the ED, 75 were admitted, and 23 were discharged, including one urgent placement. Compared with discharged patients (0.39 ± SD 0.16), those admitted had a higher mean FI-CGA (0.48 ± 0.13; p < .01). Greater mobility dependence (2% in discharged vs. 32% in admitted; p < .05) was notable. Conclusions Discharge decisions require assessment of medical, functional, and social problems. Ill, frail patients often can be discharged home when social and nursing support can be provided. The degree of frailty, impaired mobility, and likely delirium must be taken into account when planning for their care. PMID:27076860

  19. McGraw Hill encyclopedia of science and technology. An international reference work in fifteen volumes including an index

    SciTech Connect

    Not Available

    1982-01-01

    This extensively revised and updated 5th Edition features contributions by 3000 distinguished experts - including 16 Nobel Prize winners - working with an international advisory board and 60 consulting editors. Thorough coverage is devoted to 75 separate disciplines in science and technology, from acoustics and biochemistry through fluid mechanics and geophysics to thermodynamics and vertebrate zoology. Detailed entries examine not only the physical and natural sciences, but also all engineering disciplines, discussing both the basic and the most recent theories, concepts, terminology, discoveries, materials, methods, and techniques. All of the new developments and technical advances that have occurred during the last five years - in each of the 75 disciplines - have been added to the encyclopedia and are explored in depth. Completely new material deals with such timely and newsworthy subjects as genetic engineering, artificial intelligence, nuclear medicine, desertification, psycholinguistics, industrial robots, and immunoassay. Also covered in extensive entries are such current topics as video disk recording, metallic glasses, acoustic levitation, magnetic bubble memory, gluons, and computerized tomography. The encyclopedia includes more than 15,000 photographs, drawings, maps, charts, and diagrams, shown in full-color, two-color, or black-and-white reproductions.

  20. International collaborative study of the endogenous reference gene, sucrose phosphate synthase (SPS), used for qualitative and quantitative analysis of genetically modified rice.

    PubMed

    Jiang, Lingxi; Yang, Litao; Zhang, Haibo; Guo, Jinchao; Mazzara, Marco; Van den Eede, Guy; Zhang, Dabing

    2009-05-13

    One rice ( Oryza sativa ) gene, sucrose phosphate synthase (SPS), has been proven to be a suitable endogenous reference gene for genetically modified (GM) rice detection in a previous study. Herein are the reported results of an international collaborative ring trial for validation of the SPS gene as an endogenous reference gene and its optimized qualitative and quantitative polymerase chain reaction (PCR) systems. A total of 12 genetically modified organism (GMO) detection laboratories from seven countries participated in the ring trial and returned their results. The validated results confirmed the species specificity of the method through testing 10 plant genomic DNAs, low heterogeneity, and a stable single-copy number of the rice SPS gene among 7 indica varieties and 5 japonica varieties. The SPS qualitative PCR assay was validated with a limit of detection (LOD) of 0.1%, which corresponded to about 230 copies of haploid rice genomic DNA, while the limit of quantification (LOQ) for the quantitative PCR system was about 23 copies of haploid rice genomic DNA, with acceptable PCR efficiency and linearity. Furthermore, the bias between the test and true values of eight blind samples ranged from 5.22 to 26.53%. Thus, we believe that the SPS gene is suitable for use as an endogenous reference gene for the identification and quantification of GM rice and its derivates. PMID:19326953

  1. Possible Geomagnetic and Environmental Symptoms in the Area of Athens During the Solar Cycle No 22

    NASA Astrophysics Data System (ADS)

    Nastos, P. T.; Paliatsos, A. G.; Korbakis, G. K.; Tritakis, V. P.; Bergiannaki, A.; Psarros, K.; Paparrigopoulos, P.; Stafanis, K.

    The goal of this research is to confirm possible influences of environmental and geomagnetic variability in psychiatric hygiene of sensitive and heavily psychological patients. Three yearly samples of psychological patients consisted by four thousand cases (4000) each have been studied. The patients have been filed by the psychiatric clinic of the Eginition hospital in Athens where the three samples have been compiled during three very characteristic years of the No 22 11-year cycle, the maximum (1989), the minimum (1996) and one intermediate year of the descending branch (1994). A file with five to eight psychological symptoms like depression, sleep disturbance anxiety, aggressiveness etc. is attached to every patient. Each of these symptoms is correlated to the local geomagnetic index (k-index), the international geomagnetic index (Dst) and the environmental index (DI, Discomfort Index) in both daily and monthly basis. A clear seasonal variation in almost all symptoms and samples is present with maximum at the end of summer (August/September) and minimum at the end of winter (February-March). In addition very significant correlations among DI, Dst and some psychological symptoms appear. The main conclusion is that meteorological and geomagnetic factors play a significant role in the formation of sensitive psychological patients, behavior

  2. Natural variability of atmospheric temperatures and geomagnetic intensity over a wide range of time scales

    PubMed Central

    Pelletier, Jon D.

    2002-01-01

    The majority of numerical models in climatology and geomagnetism rely on deterministic finite-difference techniques and attempt to include as many empirical constraints on the many processes and boundary conditions applicable to their very complex systems. Despite their sophistication, many of these models are unable to reproduce basic aspects of climatic or geomagnetic dynamics. We show that a simple stochastic model, which treats the flux of heat energy in the atmosphere by convective instabilities with random advection and diffusive mixing, does a remarkable job at matching the observed power spectrum of historical and proxy records for atmospheric temperatures from time scales of one day to one million years (Myr). With this approach distinct changes in the power-spectral form can be associated with characteristic time scales of ocean mixing and radiative damping. Similarly, a simple model of the diffusion of magnetic intensity in Earth's core coupled with amplification and destruction of the local intensity can reproduce the observed 1/f noise behavior of Earth's geomagnetic intensity from time scales of 1 (Myr) to 100 yr. In addition, the statistics of the fluctuations in the polarity reversal rate from time scales of 1 Myr to 100 Myr are consistent with the hypothesis that reversals are the result of variations in 1/f noise geomagnetic intensity above a certain threshold, suggesting that reversals may be associated with internal fluctuations rather than changes in mantle thermal or magnetic boundary conditions. PMID:11875208

  3. Time-correlated patterns from spherical harmonic expansions: Application to geomagnetism

    NASA Astrophysics Data System (ADS)

    Pais, M. A.; Alberto, P.; Pinheiro, F. J. G.

    2015-12-01

    We use empirical orthogonal function analysis (EOFA) directly on sets of Schmidt spherical harmonic (SH) coefficients modeling the internal geomagnetic field or its time derivatives at different epochs. We show how to properly use the method such that the application of EOFA to either spatial or spectral domains leads to the same results, bypassing the need to work on snapshots of field charts synthesized from SHs. In case a spatial grid is required, we point out which is the best grid to use. We apply the method to the CM4 geomagnetic field model to illustrate the differences in EOFA modes obtained with and without corrections. Once the corrected main modes of secular acceleration (SA) have been singled out, we retrieve previous results showing that the 1969, 1978, and 1991 geomagnetic field acceleration jumps have the same spatial pattern. A new finding in this study is that the same spatial pattern is present in principal modes of secular variation which, once inverted, may provide the flow responsible for the jerk sequence. Another finding is the unveiling of a different spatial structure common to a second group of jerks with SA pulses around 1985 and 1996, displaying a localization very similar to SA pulses identified in 2006 and 2009 using recent satellite data. Finally, if properly handled, the EOFA can be directly applied to a grid of data values of the geomagnetic field in order to produce SH models of decorrelated modes which may help to separate different sources of the field.

  4. Natural variability of atmospheric temperatures and geomagnetic intensity over a wide range of time scales.

    PubMed

    Pelletier, Jon D

    2002-02-19

    The majority of numerical models in climatology and geomagnetism rely on deterministic finite-difference techniques and attempt to include as many empirical constraints on the many processes and boundary conditions applicable to their very complex systems. Despite their sophistication, many of these models are unable to reproduce basic aspects of climatic or geomagnetic dynamics. We show that a simple stochastic model, which treats the flux of heat energy in the atmosphere by convective instabilities with random advection and diffusive mixing, does a remarkable job at matching the observed power spectrum of historical and proxy records for atmospheric temperatures from time scales of one day to one million years (Myr). With this approach distinct changes in the power-spectral form can be associated with characteristic time scales of ocean mixing and radiative damping. Similarly, a simple model of the diffusion of magnetic intensity in Earth's core coupled with amplification and destruction of the local intensity can reproduce the observed 1/f noise behavior of Earth's geomagnetic intensity from time scales of 1 (Myr) to 100 yr. In addition, the statistics of the fluctuations in the polarity reversal rate from time scales of 1 Myr to 100 Myr are consistent with the hypothesis that reversals are the result of variations in 1/f noise geomagnetic intensity above a certain threshold, suggesting that reversals may be associated with internal fluctuations rather than changes in mantle thermal or magnetic boundary conditions. PMID:11875208

  5. The signature of the 2011 Tohoku mega earthquake on the geomagnetic field measurements in Japan

    NASA Astrophysics Data System (ADS)

    Takla, E. M.; Yumoto, K.; Okano, S.; Uozumi, T.; Abe, S.

    2013-12-01

    On 11 March 2011 at 05:46:23 UTC, a mega earthquake (EQ) with magnitude (Mw) 9.0 [The 2011 Tohoku Earthquake] occurred at a depth of about 24 km near the East coast of Honshu Island, Japan as a result of a thrust faulting on or near the subduction plate boundary between the Pacific and North American plates. Geomagnetic data from MAGDAS and Geospatial Information Authority of Japan (GSI) networks have been analyzed to examine the signature of the 2011 Tohoku earthquake on the geomagnetic field measurements in Japan. Results of data analysis indicate about 5 nT increase in the total geomagnetic field intensity in the vicinity of the epicenter of 2011Tohoku EQ compared with other reference stations. Moreover, the annual range of the Z-component daily variations tends to decrease near the epicenter before the occurrence of the Tohoku EQ. Concerning the ULF emissions; the Pc 3 amplitude ratio (ZPc3/HPc3) near the epicenter at the Onagawa [ONW] station showed a good correlation with other remote reference stations before the Tohoku EQ but it started to decrease with no correlation to other stations a few weeks before the 2011 Tohoku EQ. On the other hand, the Pc 3 amplitude ratio at ONW station showed a clear anti-correlation compared with reference stations after the 2011 Tohoku EQ.

  6. Study of Ring Current Dynamics During Geomagnetic Storms

    NASA Technical Reports Server (NTRS)

    Jordanova, Vania K.

    2000-01-01

    This research program considered modeling the dynamical evolution of the ring current during several geomagnetic storms. The first year (6/01/1997-5/31/1998) of this successful collaborative research between the University of New Hampshire (UNH) and the University of California Los Angeles (UCLA) was supported by NASA grant NAG5-4680. The second and third years (6/01/1998-5/31/2000) were funded at UNH under NASA grant NAG5-7368. Research work at UNH concentrated on further development of a kinetic model to treat all of the important physical processes that affect the ring current ion population during storm conditions. This model was applied to simulate ring current development during several International Solar-Terrestrial Physics (ISTP) events, and the results were directly compared to satellite observations. A brief description of our major accomplishments and a list of the publications and presentations resulting from this effort are given.

  7. On the local operational geomagnetic index K calculation

    NASA Astrophysics Data System (ADS)

    Stankov, Stan; Stegen, Koen; Wautelet, Gilles; Warnant, Rene

    2010-05-01

    There is an ongoing demand for services that can provide real-time assessment of the (global and local) geomagnetic activity and identified as being of importance to the exploration geophysics, radio communications and precise position/navigation practices, space weather research and modelling, etc. Such services depend largely on the reduction of solar, geomagnetic and ionospheric observations to generate activity indices, one of the most widely used being the K index. The K index is a quasi-logarithmic index characterising the 3-hourly range in transient magnetic activity relative to the regular "quiet-day" activity for a single site location. A derivative "planetary" index (Kp), the mean standardized K index from several globally distributed stations, provides a convenient measure of the global geomagnetic activity. Computer-based derivation of K/Kp indices was a major step towards higher efficiency and lower costs. Nowadays, automated data acquisition, processing and generating the index in real time is mandatory for any reliable service. However, Kp may not be accurate enough when monitoring disturbances of smaller scale, so the local K index (derived from the nearest magnetic station/s) might be considered as the better choice. Moreover, the 3-hour time scale is much larger than the shorter characteristic time of localised ionospheric phenomena that are of particular interest to us. Our experience in developing a novel nowcast system for local operational geomagnetic index K calculation (K-LOGIC) will be presented. The system is based on a fully automated computer procedure for real-time digital magnetogram data acquisition, screening the dataset and removing the outliers, establishing the solar regular (Sr) variation of the geomagnetic field, calculating the K index, and issuing an alert if storm-level activity is indicated. This is a time-controlled (rather than event-driven) system delivering as regular output (time resolution set to 1 hour) the K value

  8. Understanding and Predicting Geomagnetic Dipole Reversals Via Low Dimensional Models and Data Assimilation

    NASA Astrophysics Data System (ADS)

    Morzfeld, M.; Fournier, A.; Hulot, G.

    2014-12-01

    We investigate the geophysical relevance of low-dimensional models of the geomagnetic dipole fieldby comparing these models to the signed relative paleomagnetic intensity over the past 2 Myr.The comparison is done via Bayesian statistics, implemented numerically by Monte Carlo (MC) sampling.We consider several MC schemes, as well as two data sets to show the robustness of our approach with respect to its numerical implementation and to the details of how the data are collected.The data we consider are the Sint-2000 [1] and PADM2M [2] data sets.We consider three stochastic differential equation (SDE) models and one deterministic model. Experiments with synthetic data show that it is feasible that a low dimensional modelcan learn the geophysical state from data of only the dipole field,and reveal the limitations of the low-dimensional models.For example, the G12 model [3] (a deterministic model that generates dipole reversals by crisis induced intermittency)can only match either one of the two important time scales we find in the data. The MC sampling approach also allows usto use the models to make predictions of the dipole field.We assess how reliably dipole reversals can be predictedwith our approach by hind-casting five reversals documented over the past 2 Myr. We find that, besides its limitations, G12 can be used to predict reversals reliably,however only with short lead times and over short horizons. The scalar SDE models on the other hand are not useful for prediction of dipole reversals.References Valet, J.P., Maynadier,L and Guyodo, Y., 2005, Geomagnetic field strength and reversal rate over the past 2 Million years, Nature, 435, 802-805. Ziegler, L.B., Constable, C.G., Johnson, C.L. and Tauxe, L., 2011, PADM2M: a penalized maximum likelihood model of the 0-2 Ma paleomagnetic axial dipole moment, Geophysical Journal International, 184, 1069-1089. Gissinger, C., 2012, A new deterministic model for chaotic reversals, European Physical Journal B, 85:137.

  9. Asbestos and Asbestos-related Diseases in Vietnam: In reference to the International Labor Organization/World Health Organization National Asbestos Profile

    PubMed Central

    Pham, Van Hai; Lan Tran, Thi Ngoc; Le, Giang Vinh; Movahed, Mehrnoosh; Jiang, Ying; Pham, Nguyen Ha; Ogawa, Hisashi; Takahashi, Ken

    2013-01-01

    This paper describes progress on formulating a national asbestos profile for the country of Vietnam. The Center of Asbestos Resource, Vietnam, formulated a National Profile on Asbestos-related Occupational Health, with due reference to the International Labor Organization/World Health Organization National Asbestos Profile. The Center of Asbestos Resource was established by the Vietnamese Health Environment Management Agency and the National Institute of Labor Protection, with the support of the Australian Agency for International Development, as a coordinating point for asbestos-related issues in Vietnam. Under the National Profile on Asbestos-related Occupational Health framework, the Center of Asbestos Resource succeeded in compiling relevant information for 15 of the 18 designated items outlined in the International Labor Organization/World Health Organization National Asbestos Profile, some overlaps of the information items notwithstanding. Today, Vietnam continues to import and use an average of more than 60,000 metric tons of raw asbestos per year. Information on asbestos-related diseases is limited, but the country has begun to diagnose mesothelioma cases, with the technical cooperation of Japan. As it stands, the National Profile on Asbestos-related Occupational Health needs further work and updating. However, we envisage that the National Profile on Asbestos-related Occupational Health will ultimately facilitate the smooth transition to an asbestos-free Vietnam. PMID:23961336

  10. Artificial reproduction of magnetic fields produced by a natural geomagnetic storm increases systolic blood pressure in rats

    NASA Astrophysics Data System (ADS)

    Martínez-Bretón, J. L.; Mendoza, B.; Miranda-Anaya, M.; Durán, P.; Flores-Chávez, P. L.

    2016-04-01

    The incidence of geomagnetic storms may be associated with changes in circulatory physiology. The way in which the natural variations of the geomagnetic field due to solar activity affects the blood pressure are poorly understood and require further study in controlled experimental designs in animal models. In the present study, we tested whether the systolic arterial pressure (AP) in adult rats is affected by simulated magnetic fields resembling the natural changes of a geomagnetic storm. We exposed adult rats to a linear magnetic profile that simulates the average changes associated to some well-known geomagnetic storm phases: the sudden commencement and principal phase. Magnetic stimulus was provided by a coil inductor and regulated by a microcontroller. The experiments were conducted in the electromagnetically isolated environment of a semi-anechoic chamber. After exposure, AP was determined with a non-invasive method through the pulse on the rat's tail. Animals were used as their own control. Our results indicate that there was no statistically significant effect in AP when the artificial profile was applied, neither in the sudden commencement nor in the principal phases. However, during the experimental period, a natural geomagnetic storm occurred, and we did observe statistically significant AP increase during the sudden commencement phase. Furthermore, when this storm phase was artificially replicated with a non-linear profile, we noticed a 7 to 9 % increase of the rats' AP in relation to a reference value. We suggested that the changes in the geomagnetic field associated with a geomagnetic storm in its first day could produce a measurable and reproducible physiological response in AP.

  11. Steady induction effects in geomagnetism. Part 1A: Steady motional induction of geomagnetic chaos

    NASA Technical Reports Server (NTRS)

    Voorhies, Coerte V.

    1992-01-01

    Geomagnetic effects of magnetic induction by hypothetically steady fluid motion and steady magnetic flux diffusion near the top of Earth's core are investigated using electromagnetic theory, simple magnetic earth models, and numerical experiments with geomagnetic field models. The problem of estimating a steady fluid velocity field near the top of Earth's core which induces the secular variation indicated by broad-scale models of the observed geomagnetic field is examined and solved. In Part 1, the steady surficial core flow estimation problem is solved in the context of the source-free mantle/frozen-flux core model. In the first paper (IA), the theory underlying such estimates is reviewed and some consequences of various kinematic and dynamic flow hypotheses are derived. For a frozen-flux core, fluid downwelling is required to change the mean square normal magnetic flux density averaged over the core-mantle boundary. For surficially geostrophic flow, downwelling implies poleward flow. The solution of the forward steady motional induction problem at the surface of a frozen-flux core is derived and found to be a fine, easily visualized example of deterministic chaos. Geomagnetic effects of statistically steady core surface flow may well dominate secular variation over several decades. Indeed, effects of persistent, if not steady, surficially geostrophic core flow are described which may help explain certain features of the present broad-scale geomagnetic field and perhaps paleomagnetic secular variation.

  12. Geomagnetic variations and solar activity relationship in the South Atlantic Geomagnetic Anomaly -SAMA

    NASA Astrophysics Data System (ADS)

    Claudir da Silva, Andirlei; Schuch, Nelson Jorge; Babulal Trivedi, Nalin; Frigo, Everton; Rigon Silva, Willian; Souza Savian, Fernando; Ronan Coelho Stekel, Tardelli; Espindola Antunes, Cassio; de Siqueira, Josemar

    Comparative studies between the ACE satellite's solar wind parameters (speed and density of the solar plasma ) and the geomagnetic variations recorded in the Southern Space Observatory -SSO/CRS/INPE -MCT, São Martinho da Serra, (29,43° S, 53,82° W, 488m a.s.l.), RS, Brazil, a were performed. The three orthogonal geomagnetic field components data were acquired with a fluxgate magnetometer with 0.5Hz acquisition rate. Comparisons between the temporal evolution of the geomagnetic field intensity and the solar wind parameters for different phases of the solar cycle were analyzed. It was possible to identify fast changes in the geomagnetic field which may be correlated with stronger or wicker solar activity with important effects around midday in the local Ionosphere. This fact confirm the existence of relationships between the local geomagnetic variations and the solar activity. The periods of higher solar activity are related to a significant increasing in the flow of electrically charged particles in the atmosphere. As consequence of the physical and chemical phenomena, associated to these particles flow increases, are damages in satellites that orbit this region, as well as the induced electric currents in the Earth surface that causes damages in the electric power systems.

  13. Geomagnetic Indices Variations And Human Physiology

    NASA Astrophysics Data System (ADS)

    Dimitrova, S.

    2007-12-01

    A group of 86 volunteers was examined on each working day in autumn 2001 and in spring 2002. Systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were registered. Pulse pressure (PP) was calculated. Data about subjective psycho-physiological complaints (SPPC) were also gathered. Altogether 2799 recordings were obtained. ANOVA was employed to check the significance of influence of daily amplitude of H-component of local geomagnetic field, daily planetary Ap-index and hourly planetary Dst-index on the physiological parameters examined. Post hoc analysis was performed to elicit the significance of differences in the factors levels. Average values of SBP, DBP, PP and SPPC of the group were found to increase statistically significantly and biologically considerably with the increase of geomagnetic indices.

  14. Geomagnetic and Solar Indices Data at NGDC

    NASA Astrophysics Data System (ADS)

    Mabie, J. J.

    2012-12-01

    The National Geophysical Data Center, Solar and Terrestrial Physics Indices program is a central repository for global indices derived at numerous organizations around the world. These datasets are used by customers to drive models, evaluate the solar and geomagnetic environment, and to understand space climate. Our goal is to obtain and disseminate this data in a timely and accurate manner, and to provide the short term McNish-Lincoln sunspot number prediction. NGDC is in partnership with the NOAA Space Weather Prediction Center (SWPC), University Center for Atmospheric Sciences (UCAR), the Potsdam Helmholtz Center (GFZ), the Solar Indices Data Center (SIDC), the World Data Center for Geomagnetism Kyoto and many other organizations. The large number of available indices and the complexity in how they are derived makes understanding the data one of the biggest challenges for the users of indices. Our data services include expertise in our indices and related datasets to provide feedback and analysis for our global customer base.

  15. Geomagnetic modeling by optimal recursive filtering

    NASA Technical Reports Server (NTRS)

    Gibbs, B. P.; Estes, R. H.

    1981-01-01

    The results of a preliminary study to determine the feasibility of using Kalman filter techniques for geomagnetic field modeling are given. Specifically, five separate field models were computed using observatory annual means, satellite, survey and airborne data for the years 1950 to 1976. Each of the individual field models used approximately five years of data. These five models were combined using a recursive information filter (a Kalman filter written in terms of information matrices rather than covariance matrices.) The resulting estimate of the geomagnetic field and its secular variation was propogated four years past the data to the time of the MAGSAT data. The accuracy with which this field model matched the MAGSAT data was evaluated by comparisons with predictions from other pre-MAGSAT field models. The field estimate obtained by recursive estimation was found to be superior to all other models.

  16. Strength of the Archean geomagnetic field and effectiveness of magnetic shielding from the young active Sun

    NASA Astrophysics Data System (ADS)

    Tarduno, J. A.

    2008-05-01

    The strength of Earth's early magnetic field is important for understanding the evolution of the core, surface environment, atmosphere and life. Paleointensity analyses of single silicate crystals indicate that the strength of the geomagnetic field 3.2 billion years ago was within 50% of the modern value (Tarduno et al., 2007), but for even earlier times it is unknown. Two ideas have been offered: (1) the geomagnetic field started shortly after core formation, and the subsequent field strength has been within a factor of 2-3 of the modern value since its initiation; (2) the field was at null values ~3.9 billion years ago and commenced thereafter. The latter scenario relies on a hypothesis to explain the amount and isotopic composition of nitrogen found in soils of the Moon; this lunar nitrogen may have been derived from Earth's atmosphere via the solar wind (Ozima et al., 2005) in the absence of geomagnetic field that would otherwise shield atmospheric erosion. The possibility of a delayed dynamo onset (Labrosse et al., 2007) will be discussed, as will our efforts to address the presence/absence of the geomagnetic field between 3.2 and 3.9 billion years ago using the terrestrial rock record. The available constraints on ancient magnetic shielding will be reviewed in light of the radiation and particle flux associated with the active young Sun. (References: Labrosse et al., A crystallizing dense magma ocean at the base of the Earth's mantle, Nature, 450, 866-868, 2007; Ozima, M., et al., Terrestrial nitrogen and noble gases in lunar soils, Nature, 436, 655-659, 2005; Tarduno, J.A. et al., Geomagnetic field strength 3.2 billion years ago recorded by single silicate crystals, Nature, 446, 657-660, 2007.)

  17. MAGSAT for geomagnetic studies over Indian region

    NASA Technical Reports Server (NTRS)

    Rastogi, R. G.; Bhargava, B. N.; Singh, B. P.; Rao, D. R. K.; Rangarajan, G. K.; Rajaram, R.; Roy, M.; Arora, B. R.; Seth, A. (Principal Investigator)

    1981-01-01

    Progress in the preparation of software for converting data tapes produced on an IBM system to data readable on a DEC-10 system, in the creation of awareness of the utility of MAGSAT data among users in India, and in making computer programs supplied by NASA operational on the DEC-10 system is reported. Papers presented to Indian users, at the IAGA fourth scientific assembly, at a symposium on interdisciplinary approaches to geomagnetism, and a paper published in Science Today are included.

  18. NOAA Plans for Geomagnetic Storm Observations

    NASA Astrophysics Data System (ADS)

    Diedrich, B. L.; Biesecker, D. A.; Mulligan, P.; Simpson, M.

    2012-12-01

    For many years, NOAA has issued geomagnetic storm watches and warnings based on coronal mass ejection (CME) imagery and in-situ solar wind measurements from research satellites. The NOAA Satellite and Information Service (NESDIS) recognizes the importance of this service to protecting technological infrastructure including power grids, polar air travel, and satellite navigation, so is actively planning to replace these assets to ensure their continued availability. NOAA, NASA, and the US Air Force are working on launching the first operational solar wind mission in 2014, the Deep Space Climate Observatory (DSCOVR), to follow NASA's Advanced Composition Explorer (ACE) in making solar wind measurements at the sun-Earth L1 for 15-60 minute geomagnetic storm warning. For continuing operations after the DSCOVR mission, one technology NOAA is looking at is solar sails that could greatly improve the lead time of geomagnetic storm warnings by stationkeeping closer to the sun than L1. We are working with NASA and private industry on the Sunjammer solar sail demonstration mission to test making solar wind measurements from a solar sail in the sun-Earth L1 region. NOAA uses CME imagery from the NASA/ESA Solar and Heliospheric Observatory (SOHO) and the NASA Solar Terrestrial Relations Observatory (STEREO) satellites to issue 1-3 day geomagnetic storm watches. For the future, NOAA worked with the Naval Research Laboratory (NRL) to develop a Compact Coronagraph (CCOR) through Phase A, and is studying ways to complete instrument development and test fly it for use in the future.

  19. Geomagnetic activity and Hale sector boundaries

    NASA Technical Reports Server (NTRS)

    Lundstedt, H.; Scherrer, P. H.; Wilcox, J. M.

    1981-01-01

    The variation of the geomagnetic activity index Ap at the IMF sector boundaries (+ to - and - to +) has been studied for three solar cycles, separating data into vernal and autumnal equinoxes. It was found that a reported increase in Ap as an effect of a Hale boundary can be better attributed to the occurrence of a negative IMF Bz component in the geocentric solar magnetospheric coordinate system and to the occurrence of high speed solar wind streams.

  20. Solar generated quasi-biennial geomagnetic variation

    NASA Technical Reports Server (NTRS)

    Sugiura, M.; Poros, D. J.

    1977-01-01

    The existence of highly correlated quasi-biennial variations in the geomagnetic field and in solar activity is demonstrated. The analysis uses a numerical filter technique applied to monthly averages of the geomagnetic horizontal component and of the Zurich relative sunspot number. Striking correlations are found between the quasi-biennial geomagnetic variations determined from several magnetic observatories located at widely different longitudes, indicating a worldwide nature of the obtained variation. The correlation coefficient between the filtered Dst index and the filtered relative sunspot number is found to be -0.79 at confidence level greater than 99% with a time-lag of 4 months, with solar activity preceding the Dst variation. The correlation between the unfiltered data of Dst and of the sunspot number is also high with a similar time-lag. Such a timelag has not been discussed in the literature, and a further study is required to establish the mode of sun-earth relationship that gives this time delay.

  1. AI techniques in geomagnetic storm forecasting

    NASA Astrophysics Data System (ADS)

    Lundstedt, Henrik

    This review deals with how geomagnetic storms can be predicted with the use of Artificial Intelligence (AI) techniques. Today many different Al techniques have been developed, such as symbolic systems (expert and fuzzy systems) and connectionism systems (neural networks). Even integrations of AI techniques exist, so called Intelligent Hybrid Systems (IHS). These systems are capable of learning the mathematical functions underlying the operation of non-linear dynamic systems and also to explain the knowledge they have learned. Very few such powerful systems exist at present. Two such examples are the Magnetospheric Specification Forecast Model of Rice University and the Lund Space Weather Model of Lund University. Various attempts to predict geomagnetic storms on long to short-term are reviewed in this article. Predictions of a month to days ahead most often use solar data as input. The first SOHO data are now available. Due to the high temporal and spatial resolution new solar physics have been revealed. These SOHO data might lead to a breakthrough in these predictions. Predictions hours ahead and shorter rely on real-time solar wind data. WIND gives us real-time data for only part of the day. However, with the launch of the ACE spacecraft in 1997, real-time data during 24 hours will be available. That might lead to the second breakthrough for predictions of geomagnetic storms.

  2. Anomalous geomagnetic variations associated with the volcanic activity of the Mayon volcano, Philippines during 2009-2010

    NASA Astrophysics Data System (ADS)

    Takla, E. M.; Yoshikawa, A.; Kawano, H.; Uozumi, T.; Abe, S.

    2014-12-01

    Local anomalous geomagnetic variations preceding and accompanying the volcanic eruptions had been reported by several researchers. This paper uses continuous high-resolution geomagnetic data to examine the occurrence of any anomalous geomagnetic field variations that possibly linked with the volcanic eruption of the Mayon volcano, Philippines during 2009-2010. The nearest geomagnetic observing point from the Mayon volcano is the Legazpi (LGZ) station, Philippines; which is located about 13 km South of the Mayon volcano. The amplitude range of daily variations and the amplitude of Ultra Low Frequency emissions in the Pc3 range (Pc3; 10-45 s) were examined at the LGZ station and also were compared with those from the Davao (DAV) station, Philippines as a remote reference station. Both the LGZ and DAV stations belong to the MAGDAS Network. The result of data analysis reveals significant anomalous changes in the amplitude range of daily variations and the Pc3 amplitude at the LGZ station before and during the volcanic eruption of the Mayon volcano. From the obtained results, it appears that the observed anomalous variations are dependent on the change in the underground conductivity connected with variation in the physical properties of the Earth's crust due to the activity of the Mayon volcano. Therefore, these anomalous geomagnetic variations are considered to be of a local volcanic origin.

  3. Monitoring the ionospheric total electron content variations over the Korean Peninsula using a GPS network during geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Choi, Byung-Kyu; Lee, Sang-Jeong; Park, Jong-Uk

    2011-06-01

    We have established a regional ionospheric model (RIM) for investigating changes in the total electron content (TEC) over South Korea using 38 Korean GPS reference stations. The inverse distance weighted (IDW) interpolation method was applied to create a two-dimensional ionospheric map of vertical TEC units (TECU) based on a grid. To examine the diurnal patterns of ionospheric TEC over South Korea, we first processed the GPS data from a geomagnetically quiet period of 10 days. In a second step, we compared the estimated GPS-TEC variations with the changes in geomagnetic activity indices (the K p and D st indices) and the auroral electrojet index (AE) as a function of universal time (UT) on 4 and 20 November, 2003. The GPS-TEC responses for those storm events were proportional to the geomagnetic activity at this mid-latitude location. The sudden increases in ionospheric TEC (SITEC) caused by the geomagnetic storms were detected. The variations in GPS-TEC may help reveal the processes of ionospheric disturbances caused by geomagnetic storms.

  4. Application of the ICRP/ICRU reference computational phantoms to internal dosimetry: calculation of specific absorbed fractions of energy for photons and electrons.

    PubMed

    Hadid, L; Desbrée, A; Schlattl, H; Franck, D; Blanchardon, E; Zankl, M

    2010-07-01

    The emission of radiation from a contaminated body region is connected with the dose received by radiosensitive tissue through the specific absorbed fractions (SAFs) of emitted energy, which is therefore an essential quantity for internal dose assessment. A set of SAFs were calculated using the new adult reference computational phantoms, released by the International Commission on Radiological Protection (ICRP) together with the International Commission on Radiation Units and Measurements (ICRU). Part of these results has been recently published in ICRP Publication 110 (2009 Adult reference computational phantoms (Oxford: Elsevier)). In this paper, we mainly discuss the results and also present them in numeric form. The emission of monoenergetic photons and electrons with energies ranging from 10 keV to 10 MeV was simulated for three source organs: lungs, thyroid and liver. SAFs were calculated for four target regions in the body: lungs, colon wall, breasts and stomach wall. For quality assurance purposes, the simulations were performed simultaneously at the Helmholtz Zentrum München (HMGU, Germany) and at the Institute for Radiological Protection and Nuclear Safety (IRSN, France), using the Monte Carlo transport codes EGSnrc and MCNPX, respectively. The comparison of results shows overall agreement for photons and high-energy electrons with differences lower than 8%. Nevertheless, significant differences were found for electrons at lower energy for distant source/target organ pairs. Finally, the results for photons were compared to the SAF values derived using mathematical phantoms. Significant variations that can amount to 200% were found. The main reason for these differences is the change of geometry in the more realistic voxel body models. For electrons, no SAFs have been computed with the mathematical phantoms; instead, approximate formulae have been used by both the Medical Internal Radiation Dose committee (MIRD) and the ICRP due to the limitations imposed

  5. Application of the ICRP/ICRU reference computational phantoms to internal dosimetry: calculation of specific absorbed fractions of energy for photons and electrons

    NASA Astrophysics Data System (ADS)

    Hadid, L.; Desbrée, A.; Schlattl, H.; Franck, D.; Blanchardon, E.; Zankl, M.

    2010-07-01

    The emission of radiation from a contaminated body region is connected with the dose received by radiosensitive tissue through the specific absorbed fractions (SAFs) of emitted energy, which is therefore an essential quantity for internal dose assessment. A set of SAFs were calculated using the new adult reference computational phantoms, released by the International Commission on Radiological Protection (ICRP) together with the International Commission on Radiation Units and Measurements (ICRU). Part of these results has been recently published in ICRP Publication 110 (2009 Adult reference computational phantoms (Oxford: Elsevier)). In this paper, we mainly discuss the results and also present them in numeric form. The emission of monoenergetic photons and electrons with energies ranging from 10 keV to 10 MeV was simulated for three source organs: lungs, thyroid and liver. SAFs were calculated for four target regions in the body: lungs, colon wall, breasts and stomach wall. For quality assurance purposes, the simulations were performed simultaneously at the Helmholtz Zentrum München (HMGU, Germany) and at the Institute for Radiological Protection and Nuclear Safety (IRSN, France), using the Monte Carlo transport codes EGSnrc and MCNPX, respectively. The comparison of results shows overall agreement for photons and high-energy electrons with differences lower than 8%. Nevertheless, significant differences were found for electrons at lower energy for distant source/target organ pairs. Finally, the results for photons were compared to the SAF values derived using mathematical phantoms. Significant variations that can amount to 200% were found. The main reason for these differences is the change of geometry in the more realistic voxel body models. For electrons, no SAFs have been computed with the mathematical phantoms; instead, approximate formulae have been used by both the Medical Internal Radiation Dose committee (MIRD) and the ICRP due to the limitations imposed

  6. Isolated sleep paralysis, vivid dreams and geomagnetic influences: II.

    PubMed

    Conesa, J

    1997-10-01

    This report describes a test of the hypothesis that significant changes in the ambient geomagnetic field are associated with altered normal nighttime dream patterns. Specifically, it was predicted that there would be a greater incidence of isolated sleep, paralysis or vivid dreams with abrupt rises and falls of geomagnetic activity. The author's (JC) and a second subject's (KC) daily reports of dream-recall were analyzed in the context of daily fluctuations of geomagnetic activity (K indices). Two analyses of variance indicated (i) significantly higher geomagnetic activity three days before a recorded isolated sleep paralysis event and (ii) significantly lower geomagnetic activity three days before an unusually vivid dream took place. Conversely, geomagnetic activity did not fluctuate significantly for randomly selected days. Testing a large sample over time is required for confirmation and extension of this work. PMID:9347546

  7. Visualization of geomagnetic field for education and outreach

    NASA Astrophysics Data System (ADS)

    Hatakeyama, T.

    2010-12-01

    Since April 2007 in the project "MAGE" (Mapping Applications to Geomagnetic Environments) we publish tools for visualization of the geomagnetic field on the web. Now five kinds of the geomagnetic field flucuation (from observations and paleomagnetic results) and geodynamo models are freely downloadable from our website, http://mage-p.org/. Access the webpage, download the KML files and open them from Google Earth, then you can experience changing geomagnetic field lines and observations, inclinations, declination, field strength and others, on the Earth's surface. One of our actions in the project is preparation of the documentations of the geomagnetic field and its fluctuations for education and outreach. Especially in Japan, there are poor treatments in the education during elementary and high schools, and the expository writing of the geomagnetic field and concerned articles are also scarce. Moreover, we provide the movie files and stereoscopic visions for the user experiences of the 3D images.

  8. Precision improvement in dark-field microscopy imaging by using gold nanoparticles as an internal reference: a combined theoretical and experimental study.

    PubMed

    Ma, Jun; Liu, Yue; Gao, Peng Fei; Zou, Hong Yan; Huang, Cheng Zhi

    2016-04-28

    Low accuracy is a big obstacle in the dark-field microscopy imaging (iDFM) technique in practical applications. In order to reduce the deviations and fluctuations in the observed or snapped scattered light in the iDFM technique caused by unavoidable measurement errors, bare gold nanoparticles (AuNPs) were introduced as an internal reference (IR). The feasibility of using AuNPs as the IR in iDFM in theory was verified. The function of the IR in improving the precision of the acquired data through post data analysis was identified by three kinds of experiments: monitoring the oxidation process of silver nanoparticles (AgNPs) at room temperature, quantifying the level of glucose with AgNPs used as probes and quantifying the change in the light intensity of AuNPs after the plasmon resonance energy transfer (PRET) between AuNPs and tetramethylrhodamine (TAMRA). PMID:27065307

  9. Precision improvement in dark-field microscopy imaging by using gold nanoparticles as an internal reference: a combined theoretical and experimental study

    NASA Astrophysics Data System (ADS)

    Ma, Jun; Liu, Yue; Gao, Peng Fei; Zou, Hong Yan; Huang, Cheng Zhi

    2016-04-01

    Low accuracy is a big obstacle in the dark-field microscopy imaging (iDFM) technique in practical applications. In order to reduce the deviations and fluctuations in the observed or snapped scattered light in the iDFM technique caused by unavoidable measurement errors, bare gold nanoparticles (AuNPs) were introduced as an internal reference (IR). The feasibility of using AuNPs as the IR in iDFM in theory was verified. The function of the IR in improving the precision of the acquired data through post data analysis was identified by three kinds of experiments: monitoring the oxidation process of silver nanoparticles (AgNPs) at room temperature, quantifying the level of glucose with AgNPs used as probes and quantifying the change in the light intensity of AuNPs after the plasmon resonance energy transfer (PRET) between AuNPs and tetramethylrhodamine (TAMRA).Low accuracy is a big obstacle in the dark-field microscopy imaging (iDFM) technique in practical applications. In order to reduce the deviations and fluctuations in the observed or snapped scattered light in the iDFM technique caused by unavoidable measurement errors, bare gold nanoparticles (AuNPs) were introduced as an internal reference (IR). The feasibility of using AuNPs as the IR in iDFM in theory was verified. The function of the IR in improving the precision of the acquired data through post data analysis was identified by three kinds of experiments: monitoring the oxidation process of silver nanoparticles (AgNPs) at room temperature, quantifying the level of glucose with AgNPs used as probes and quantifying the change in the light intensity of AuNPs after the plasmon resonance energy transfer (PRET) between AuNPs and tetramethylrhodamine (TAMRA). Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08837b

  10. Interplanetary magnetic sector polarity inferred from polar geomagnetic field observations

    NASA Technical Reports Server (NTRS)

    Friis-Christensen, E.; Lassen, K.; Wilcox, J. M.; Gonzalez, W.; Colburn, D. S.

    1971-01-01

    In order to infer the interplanetary sector polarity from polar geomagnetic field diurnal variations, measurements were carried out at Godhavn and Thule (Denmark) Geomagnetic Observatories. The inferred interplanetary sector polarity was compared with the polarity observed at the same time by Explorer 33 and 35 magnetometers. It is shown that the polarity (toward or away from the sun) of the interplanetary magnetic field can be reliably inferred from observations of the polar cap geomagnetic fields.

  11. Disturbances in the US electric grid associated with geomagnetic activity

    NASA Astrophysics Data System (ADS)

    Schrijver, Carolus J.; Mitchell, Sarah D.

    2013-05-01

    Large solar explosions are responsible for space weather that can impact technological infrastructure on and around Earth. Here, we apply a retrospective cohort exposure analysis to quantify the impacts of geomagnetic activity on the US electric power grid for the period from 1992 through 2010. We find, with more than 3σ significance, that approximately 4% of the disturbances in the US power grid reported to the US Department of Energy are attributable to strong geomagnetic activity and its associated geomagnetically induced currents.

  12. Coseismic ionospheric and geomagnetic disturbances caused by great earthquakes

    NASA Astrophysics Data System (ADS)

    Hao, Yongqiang; Zhang, Donghe; Xiao, Zuo

    2016-04-01

    Despite primary energy disturbances from the Sun, oscillations of the Earth surface due to a large earthquake will couple with the atmosphere and therefore the ionosphere, then the so-called coseismic ionospheric disturbances (CIDs) can be detected in the ionosphere. Using a combination of techniques, total electron content, HF Doppler, and ground magnetometer, a new time-sequence of such effects propagation were developed on observational basis and ideas on explanation provided. In the cases of 2008 Wenchuan and 2011 Tohoku earthquakes, infrasonic waves accompanying the propagation of seismic Rayleigh waves were observed in the ionosphere by all the three kinds of techniques. This is the very first report to present CIDs recorded by different techniques at co-located sites and profiled with regard to changes of both ionospheric plasma and current (geomagnetic field) simultaneously. Comparison between the oceanic (2011 Tohoku) and inland (2008 Wenchuan) earthquakes revealed that the main directional lobe of latter case is more distinct which is perpendicular to the direction of the fault rupture. We argue that the different fault slip (inland or submarine) may affect the way of couplings of lithosphere with atmosphere. References Zhao, B., and Y. Hao (2015), Ionospheric and geomagnetic disturbances caused by the 2008 Wenchuan earthquake: A revisit, J. Geophys. Res. Space Physics, 120, doi:10.1002/2015JA021035. Hao, Y. Q., Z. Xiao, and D. H. Zhang (2013), Teleseismic magnetic effects (TMDs) of 2011 Tohoku earthquake, J. Geophys. Res. Space Physics, 118, 3914-3923, doi:10.1002/jgra.50326. Hao, Y. Q., Z. Xiao, and D. H. Zhang (2012), Multi-instrument observation on co-seismic ionospheric effects after great Tohoku earthquake, J. Geophys. Res., 117, A02305, doi:10.1029/2011JA017036.

  13. Investigation of the Effects of Solar and Geomagnetic Changes on the Total Electron Content: Mid-Latitude Region

    NASA Astrophysics Data System (ADS)

    Ulukavak, Mustafa; Yalcinkaya, Mualla

    2016-04-01

    The Global Positioning System (GPS) is used as an important tool for ionosphere monitoring and obtaining the Total Electron Content (TEC). GPS satellites, positioned in the Earth's orbit, are used as sensors to investigate the space weather conditions. In this study, solar and geomagnetic activity variations were investigated between the dates 1 March-30 June 2015 for the mid-latitude region. GPS-TEC variations were calculated for each selected International GNSS Service (IGS) station in Europe. GNSS data was obtained from Crustal Dynamics Data and Information System (CDDIS) archive. Solar and geomagnetic activity indices (Kp, F10.7 ve Dst) were obtained from the Oceanic and Atmospheric Administration (NOAA), the Canadian Space Weather Forecast Centre (CSWFC) and Data Analysis Center for geomagnetism and Space Magnetism Graduate School of Science, Kyoto University (WDC) archives. GPS-TEC variations were determined for the quiet periods of the solar and geomagnetic activities. GPS-TEC changes were then compared with respect to the quiet periods of the solar and geomagnetic activities. Global Ionosphere Maps (GIM) IONEX files, obtained from the IGS analysis center, was used to check the robustness of the GPS-TEC variations. The investigations revealed that it is possible to use the GPS-TEC data for monitoring the ionospheric disturbances.

  14. Geomagnetic field models incorporating physical constraints on the secular variation

    NASA Technical Reports Server (NTRS)

    Constable, Catherine; Parker, Robert L.

    1993-01-01

    This proposal has been concerned with methods for constructing geomagnetic field models that incorporate physical constraints on the secular variation. The principle goal that has been accomplished is the development of flexible algorithms designed to test whether the frozen flux approximation is adequate to describe the available geomagnetic data and their secular variation throughout this century. These have been applied to geomagnetic data from both the early and middle part of this century and convincingly demonstrate that there is no need to invoke violations of the frozen flux hypothesis in order to satisfy the available geomagnetic data.

  15. Creation and application of voxelised dosimetric models, and a comparison with the current methodology as used for the International Commission on Radiological Protection's Reference Animals and Plants.

    PubMed

    Higley, K; Ruedig, E; Gomez-Fernandez, M; Caffrey, E; Jia, J; Comolli, M; Hess, C

    2015-06-01

    Over the past decade, the International Commission on Radiological Protection (ICRP) has developed a comprehensive approach to environmental protection that includes the use of Reference Animals and Plants (RAPs) to assess radiological impacts on the environment. For the purposes of calculating radiation dose, the RAPs are approximated as simple shapes that contain homogeneous distributions of radionuclides. As uncertainties in environmental dose effects are larger than uncertainties in radiation dose calculation, some have argued against more realistic dose calculation methodologies. However, due to the complexity of organism morphology, internal structure, and density, dose rates calculated via a homogenous model may be too simplistic. The purpose of this study is to examine the benefits of a voxelised phantom compared with simple shapes for organism modelling. Both methods typically use Monte Carlo methods to calculate absorbed dose, but voxelised modelling uses an exact three-dimensional replica of an organism with accurate tissue composition and radionuclide source distribution. It is a multi-stage procedure that couples imaging modalities and processing software with Monte Carlo N-Particle. These features increase dosimetric accuracy, and may reduce uncertainty in non-human biota dose-effect studies by providing mechanistic answers regarding where and how population-level dose effects arise. PMID:25856572

  16. [A comprehensive analysis of incidence of myocardial infarction in Vladikavkaz depending on solar and geomagnetic activity].

    PubMed

    Botoeva, N K; Khetarugova, l G; Rapoport, S I

    2013-01-01

    The data on myocardial infarction morbidity in Vladikavkaz for 2007-2010 were analysed with reference to solar and geomagnetic activity. Time series of morbidity in men and women were constructed and their seasonal constituent was distinguished. It was found that the number of myocardial infarctions increases on day with enhanced geomagnetic activity especially among subjects aged 50-69 years. Regression analysis of the relationship between the number of sunspots and myocardial infarctions yielded the equation of piecewise linear regression showing that 42% of the cases were due to the changes in the number of sunspots. Medium strength negative correlation was found between the number of myocardial infarctions and the recurrence index of Bz-component of the interplanetary magnetic field. It suggests an important role of chaotic dynamics of external factors in the development of myocardial infarction. PMID:25696947

  17. Geomagnetically Induced Currents, a space weather hazard. Case study - Europe under intense geomagnetic storms of the solar cycle 23

    NASA Astrophysics Data System (ADS)

    Dobrica, V.; Demetrescu, Cr.; Stefan, C.; Greculeasa, R.

    2016-05-01

    The interaction of the solar wind and heliospheric magnetic field with the magnetosphere and ionosphere results in variations of the geomagnetic field that induce hazardous electric currents in grounded technological systems (electric power and hydrocarbon transportation networks), the so-called geomagnetically induced currents (GICs). In order to evaluate the hazard induced on the European continent, we present a study of the surface electric field induced by 16 intense (Dst < -150 nT) geomagnetic storms, based on the analysis of the geomagnetic records from the European network of observatories, study that tend to solve the geophysical part of the problem. The evolution during storm development and the sources of the disturbance field are explored in case of the largest geomagnetic storm in the cycle 23 (Dst = -422 nT, November 20-21, 2003), and the geographical distribution of the maximum induced surface geoelectric field over Europe by the 16 storms considered in the study is presented. As source proxies, the Dst geomagnetic index, showing the disturbed field produced by the magnetospheric ring current at the geomagnetic equator, the AL geomagnetic index, showing the disturbed field produced by the ionospheric electrojet at auroral latitude, and the PC geomagnetic index, showing the disturbed field produced by the polar cap current, were examined.

  18. An International Reference Consensus Genetic Map with 897 Marker Loci Based on 11 Mapping Populations for Tetraploid Groundnut (Arachis hypogaea L.)

    PubMed Central

    Pandey, Manish K.; Moretzsohn, Márcio C.; Sujay, Venkataswamy; Qin, Hongde; Hong, Yanbin; Faye, Issa; Chen, Xiaoping; BhanuPrakash, Amindala; Shah, Trushar M.; Gowda, Makanahally V. C.; Nigam, Shyam N.; Liang, Xuanqiang; Hoisington, Dave A.; Guo, Baozhu; Bertioli, David J.; Rami, Jean-Francois; Varshney, Rajeev K.

    2012-01-01

    Only a few genetic maps based on recombinant inbred line (RIL) and backcross (BC) populations have been developed for tetraploid groundnut. The marker density, however, is not very satisfactory especially in the context of large genome size (2800 Mb/1C) and 20 linkage groups (LGs). Therefore, using marker segregation data for 10 RILs and one BC population from the international groundnut community, with the help of common markers across different populations, a reference consensus genetic map has been developed. This map is comprised of 897 marker loci including 895 simple sequence repeat (SSR) and 2 cleaved amplified polymorphic sequence (CAPS) loci distributed on 20 LGs (a01–a10 and b01–b10) spanning a map distance of 3, 863.6 cM with an average map density of 4.4 cM. The highest numbers of markers (70) were integrated on a01 and the least number of markers (21) on b09. The marker density, however, was lowest (6.4 cM) on a08 and highest (2.5 cM) on a01. The reference consensus map has been divided into 20 cM long 203 BINs. These BINs carry 1 (a10_02, a10_08 and a10_09) to 20 (a10_04) loci with an average of 4 marker loci per BIN. Although the polymorphism information content (PIC) value was available for 526 markers in 190 BINs, 36 and 111 BINs have at least one marker with >0.70 and >0.50 PIC values, respectively. This information will be useful for selecting highly informative and uniformly distributed markers for developing new genetic maps, background selection and diversity analysis. Most importantly, this reference consensus map will serve as a reliable reference for aligning new genetic and physical maps, performing QTL analysis in a multi-populations design, evaluating the genetic background effect on QTL expression, and serving other genetic and molecular breeding activities in groundnut. PMID:22815973

  19. Comparison of K-index Calculations between Several Geomagnetic Stations during IQDs and IDDs

    NASA Astrophysics Data System (ADS)

    Hwang, Junga; Kim, Hang-Pyo; Park, Young-Deuk

    2013-09-01

    BOH magnetometer was installed at Mt. Bohyun in 2007 and has provided continuous dataset for 3-axis geomagnetic field over the South Korea. We have calculated real-time K-index based on BOH magnetic field data using well-known FMI method. Local K-index is calculated eight times a day, per every three hours. To calculate K-index, it is critical to get the Quiet Day Curve (QDC). For QDC calculation, we take the previous one month's average of H-component. In this paper, we compared four geomagnetic stations' magnetic field data over South Korea and Japan and K-indices of each stations; Bohyun, Gangneung, Jeju, and Kakioka for two years data, 2011-2012. To investigate the difference depending on the latitude, longitude and local time in more detail, we compare K-index on International Quiet Days (IQDs) and International Disturbed Days (IDDs). As a result, we report the correlation between local K-indices are higher than those between Kp and local K-indices, and the correlation is much better after sunset than after sunrise. As the geomagnetic activity becomes stronger, the correlation between the local K-indices and global Kp-index become higher.

  20. Lower thermosphere (80-100 km) dynamics response to solar and geomagnetic activity: Overview

    NASA Technical Reports Server (NTRS)

    Kazimirovsky, E. S.

    1989-01-01

    The variations of solar and geomagnetic activity may affect the thermosphere circulation via plasma heating and electric fields, especially at high latitudes. The possibility exists that the energy involved in auroral and magnetic storms can produce significant changes of mesosphere and lower thermosphere wind systems. A study of global radar measurements of winds at 80 to 100 km region revealed the short term effects (correlation between wind field and geomagnetic storms) and long term variations over a solar cycle. It seems likely that the correlation results from a modification of planetary waves and tides propagated from below, thus altering the dynamical regime of the thermosphere. Sometimes the long term behavior points rather to a climatic variation with the internal atmospheric cause than to a direct solar control.

  1. Extracting planetary waves from geomagnetic time series using Empirical Mode Decomposition

    NASA Astrophysics Data System (ADS)

    Frühauff, Dennis; Glassmeier, Karl-Heinz; Lockwood, Michael; Heyner, Daniel

    2015-07-01

    Empirical Mode Decomposition is presented as an alternative to traditional analysis methods to decompose geomagnetic time series into spectral components. Important comments on the algorithm and its variations will be given. Using this technique, planetary wave modes of 5-, 10-, and 16-day mean periods can be extracted from magnetic field components of three different stations in Germany. In a second step, the amplitude modulation functions of these wave modes can be shown to contain significant contribution from solar cycle variation through correlation with smoothed sunspot numbers. Additionally, the data indicate connections with geomagnetic jerk occurrences, supported by a second set of data providing reconstructed near-Earth magnetic field for 150 years. Usually attributed to internal dynamo processes within the Earth's outer core, the question of who is impacting whom will be briefly discussed here.

  2. Geomagnetic imprint of the Persani volcanism

    NASA Astrophysics Data System (ADS)

    Besutiu, Lucian; Seghedi, Ioan; Zlagnean, Luminita; Atanasiu, Ligia; Popa, Razvan-Gabriel; Pomeran, Mihai; Visan, Madalina

    2016-04-01

    The Persani small volume volcanism is located in the SE corner of the Transylvanian Depression, at the north-western edge of the intra-mountainous Brasov basin. It represents the south-easternmost segment of the Neogene-Quaternary volcanic chain of the East Carpathians. The alkaline basalt monogenetic volcanic field is partly coeval with the high-K calc-alkaline magmatism south of Harghita Mountains (1-1.6 Ma). Its eruptions post-dated the calc-alkaline volcanism in the Harghita Mountains (5.3-1.6 Ma), but pre-dated the high-K calc-alkaline emissions of Ciomadul volcano (1.0-0.03 Ma). The major volcanic forms have been mapped in previous geological surveys. Still, due to the small size of the volcanoes and large extent of tephra deposits and recent sediments, the location of some vents or other volcanic structures has been incompletely revealed. To overcome this problem, the area was subject to several near-surface geophysical investigations, including paleomagnetic research. However, due to their large-scale features, the previous geophysical surveys proved to be an inappropriate approach to the volcanological issues. Therefore, during the summers of 2014 and 2015, based on the high magnetic contrast between the volcanic rocks and the hosting sedimentary formations, a detailed ground geomagnetic survey has been designed and conducted, within central Persani volcanism area, in order to outline the presence of volcanic structures hidden beneath the overlying deposits. Additionally, information on the rock magnetic properties was also targeted by sampling and analysing several outcrops in the area. Based on the acquired data, a detailed total intensity scalar geomagnetic anomaly map was constructed by using the recent IGRF12 model. The revealed pattern of the geomagnetic field proved to be fully consistent with the direction of magnetisation previously determined on rock samples. In order to enhance the signal/noise ratio, the results were further processed by

  3. Halo Coronal Mass Ejections and Geomagnetic Storms

    NASA Technical Reports Server (NTRS)

    Gopalswamy, Nat

    2009-01-01

    In this letter, I show that the discrepancies in the geoeffectiveness of halo coronal mass ejections (CMEs) reported in the literature arise due to the varied definitions of halo CMEs used by different authors. In particular, I show that the low geoeffectiveness rate is a direct consequence of including partial halo CMEs. The geoeffectiveness of partial halo CMEs is lower because they are of low speed and likely to make a glancing impact on Earth. Key words: Coronal mass ejections, geomagnetic storms, geoeffectiveness, halo CMEs.

  4. Geomagnetically Induced Currents: Progress and Issues

    NASA Astrophysics Data System (ADS)

    Thomson, Alan

    2010-05-01

    Geomagnetically induced currents (GIC) are a hazard to conducting networks such as high-voltage power and pipeline grids. GIC have been known for decades to affect power systems at higher latitudes (e.g. Europe and North America), although more recently GIC have also been found to affect power networks at middle and lower latitudes. Mitigating the effects of GIC remains an issue for the power and pipeline industries and for governments concerned with the societal and economic implications. To understand, e.g. to model and predict, GIC in conducting grids needs expertise drawn from electrical engineering, geophysics and space weather science - a truly multi-disciplinary undertaking. In terms of geophysics and space physics, issues such as Earth structure (e.g. 3D versus 1D mantle and lithospheric conductivity structure), ocean/continent conductivity contrasts, ionospheric current systems and their variability and Sun-Earth magnetic interactions are all relevant. The start of solar cycle 24 provides an opportune time to consider the status of GIC research and to assess what new studies are required in geophysical modelling and in hazard analysis. What do we need to improve on to better specify/predict GIC flowing in power grids, from ‘up-stream' observations of coronal mass ejections through to geomagnetic field measurements made during magnetic storms? In this invited review we will consider aspects of a) Measurement: how do we measure GIC in grids; b) Analysis: how do measured GIC relate to geophysical and space physics data; c) Modelling: what methods exist for modelling GIC, again in relation to other data, and how accurate are models; and d) Prediction: how predictable are GIC and what are the implications for, e.g., the power industry and national governments. We will review the more recent developments in GIC and related geomagnetism and space weather science. We will outline what issues are widely believed to now be understood and what issues remain to be

  5. Geomagnetic field modeling by optimal recursive filtering

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Five individual 5 year mini-batch geomagnetic models were generated and two computer programs were developed to process the models. The first program computes statistics (mean sigma, weighted sigma) on the changes in the first derivatives (linear terms) of the spherical harmonic coefficients between mini-batches. The program ran successfully. The statistics are intended for use in computing the state noise matrix required in the information filter. The second program is the information filter. Most subroutines used in the filter were tested, but the coefficient statistics must be analyzed before the filter is run.

  6. Advanced Theory of Deep Geomagnetic Sounding

    NASA Astrophysics Data System (ADS)

    Chave, Alan D.

    Advanced Theory of Deep Geomagnetic Sounding is a specialized treatise that covers recent work, mostly from the Soviet Union, on the theory, analysis, and interpretation of natural source electromagnetic induction processes in complex geological structures, with an emphasis on subsurface conductive anomalies. The scope of the book is limited, as suggested by the title, and the authors stress the application of electromagnetic principles to the study of regional geology and deep earth structure rather than surface exploration. The book is clearly aimed at the practicing specialist rather than the graduate student attempting to learn about the broader field of electromagnetic geophysics.

  7. Evaluation of the Geomagnetic Field Models based on Magnetometer Measurements for Satellite's Attitude Determination System

    NASA Astrophysics Data System (ADS)

    Cilden, Demet; Kaymaz, Zerefsan; Hajiyev, Chingiz

    2016-07-01

    Magnetometers are common attitude determination sensors for small satellites at low Earth orbit; therefore, magnetic field model of the Earth is necessary to estimate the satellite's attitude angles. Difference in the components of the magnetic field vectors -mostly used as unit vector. Therefore the angle between them (model and measurement data) affects the estimation accuracy of the satellite's attitude. In this study, geomagnetic field models are compared with satellite magnetic field observations in order to evaluate the models using the magnetometer results with high accuracy. For attitude determination system, IGRF model is used in most of the cases but the difference between the sensor and model increases when the geomagnetic activity occurs. Hence, several models including the empirical ones using the external variations in the Earth's geomagnetic field resulting from the solar wind and interplanetary magnetic field are of great importance in determination of the satellite's attitude correctly. IGRF model describes the internal-part of the geomagnetic field, on the other hand candidate models to IGRF, such as recently developed POMME-6 model based on Champ data, CHAOS-5 (CHAmp, Oersted, Swarm), T89 (Tsyganenko's model), include simple parameterizations of external fields of magnetospheric sources in addition to the internal field especially for low Earth orbiting satellites. Those models can be evaluated to see noticeable difference on extraterrestrial field effects on satellite's attitude determination system changing with its height. The comparisons are made between the models and observations and between the models under various magnetospheric activities. In this study, we will present our preliminary results from the comparisons and discuss their implications from the satellite attitude perspective.

  8. Geomagnetic field behaviour preceding a Superchron: new evidence for a weak Devonian geomagnetic field

    NASA Astrophysics Data System (ADS)

    Hawkins, L.; Anwar, T.; Scherbakova, V.; Biggin, A. J.; Kravchinsky, V. A.; Shatsillo, A.; Holt, J.; Pavlov, V.

    2015-12-01

    The ~50 million year transition from the peak in reversal frequency in the Middle Jurassic (~170Ma), associated with a weak geomagnetic field, to the stable and apparently strong field during the Cretaceous Normal Superchron (84-121Ma), represents a dramatic change in time-averaged geomagnetic field behaviour during the Mesozoic Era. New evidence from Siberian samples suggests there is a similar transition in geomagnetic field behaviour during the Palaeozoic, with a weak geomagnetic field in the Upper Devonian preceding the Permo-Carboniferous Superchron (262-318Ma). Both sites, the Viluy Traps and the Zharovsk complex of the Patom Margin, have seemingly reliable, published palaeomagnetic directions and new age constraints, 364.4 ± 1.7Ma (40Ar/39A) 371-377Ma (U-Pb) respectively. The samples were measured using the Thermal Thellier-Coe protocol with partial thermo-remanent magnetisation (pTRM) and tail checks and the Microwave Thellier-IZZI protocol with pTRM checks. Accepted Arai plots show positive pTRM checks, a clear relation between distinct primary directional and palaeointensity components and little to no zig-zagging. Three distinct magneto-mineralogical types were identified from SEM and rock magnetic techniques; low Ti- and intermediate Ti- titanomagnetite and possible maghemite, with mineral type affecting the success rate of samples but resulting in no significant variation in palaeointensity results. The Arai plots also commonly have a distinct two-slope concave-up shape, although non-heating, pseudo-Thellier experiments have supported this resulting from a strong overprint component rather than alteration or multi-domain effects. Results from these experiments give low site mean values between 2.3-29.9μT (Virtual Dipole Moments 4-50.6 ZAm2). The apparently periodic (~180 million years) transitions in geomagnetic field behaviour may indicate the influence of mantle convection changing heat flow across the Core Mantle Boundary.

  9. Major geomagnetic storm due to solar activity (2006-2013).

    NASA Astrophysics Data System (ADS)

    Tiwari, Bhupendra Kumar

    Major geomagnetic storm due to solar activity (2006-2013). Bhupendra Kumar Tiwari Department of Physics, A.P.S.University, Rewa(M.P.) Email: - btiwtari70@yahoo.com mobile 09424981974 Abstract- The geospace environment is dominated by disturbances created by the sun, it is observed that coronal mass ejection (CME) and solar flare events are the causal link to solar activity that produces geomagnetic storm (GMS).CMEs are large scale magneto-plasma structures that erupt from the sun and propagate through the interplanetary medium with speeds ranging from only a few km/s to as large as 4000 km/s. When the interplanetary magnetic field associated with CMEs impinges upon the earth’s magnetosphere and reconnect occur geomagnetic storm. Based on the observation from SOHO/LASCO spacecraft for solar activity and WDC for geomagnetism Kyoto for geomagnetic storm events are characterized by the disturbance storm time (Dst) index during the period 2006-2013. We consider here only intense geomagnetic storm Dst <-100nT, are 12 during 2006-2013.Geomagnetic storm with maximum Dst< -155nT occurred on Dec15, 2006 associated with halo CME with Kp-index 8+ and also verify that halo CME is the main cause to produce large geomagnetic storms.

  10. Search for correlation between geomagnetic disturbances and mortality

    NASA Technical Reports Server (NTRS)

    Lipa, B. J.; Barnes, C. W.; Sturrock, P. A.; Feinleib, M.; Rogot, E.

    1975-01-01

    Statistical evaluation of death rates in the U.S.A. from heart diseases or stroke did not show any correlation with measured geomagnetic pulsations and thus do not support a claimed relationship between geomagnetic activity and mortality rates to low frequency fluctuations of the earth's magnetic field.

  11. Empirical Storm-Time Correction to the International Reference Ionosphere Model E-Region Electron and Ion Density Parameterizations Using Observations from TIMED/SABER

    NASA Technical Reports Server (NTRS)

    Mertens, Christoper J.; Winick, Jeremy R.; Russell, James M., III; Mlynczak, Martin G.; Evans, David S.; Bilitza, Dieter; Xu, Xiaojing

    2007-01-01

    The response of the ionospheric E-region to solar-geomagnetic storms can be characterized using observations of infrared 4.3 micrometers emission. In particular, we utilize nighttime TIMED/SABER measurements of broadband 4.3 micrometers limb emission and derive a new data product, the NO+(v) volume emission rate, which is our primary observation-based quantity for developing an empirical storm-time correction the IRI E-region electron density. In this paper we describe our E-region proxy and outline our strategy for developing the empirical storm model. In our initial studies, we analyzed a six day storm period during the Halloween 2003 event. The results of this analysis are promising and suggest that the ap-index is a viable candidate to use as a magnetic driver for our model.

  12. Relationship between Dst and solar wind conditions during geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Olusesan, Bakare; Chukwuma, Victor

    2012-07-01

    A study of 224 geomagnetic storms of which 83 intense and 141 moderate storms during 1996-2006 has been carried out to investigate the relationship between Dst and solar wind plasma parameters during geomagnetic storms. The geomagnetic storms are primarily associated with two classes of drivers: the magnetic cloud and complex ejecta. Out of 83 intense geomagnetic storms studied, it was found that magnetic cloud were drivers in 43 geomagnetic storm (~ 51.8%) while complex ejecta were responsible for 40 geomagnetic storms (~ 48.2%). The correlation between Dst and B; and between Dst and Bs was 0.76 and 0.90, respectively for geomagnetic storms resulting from magnetic clouds. The correlation between Dst and B; and between Dst and Bs was 0.71 and 0.64, respectively for geomagnetic storms resulting from complex ejecta. Furthermore, it was shown that the correlation between the Dst and V for magnetic cloud and complex ejecta was 0.58 and 0.57, respectively. It was observed that the correlation between Dst and VBs for magnetic cloud and complex ejecta were 0.77 and 0.71, respectively. Further study of 141 moderate geomagnetic storms shows that the magnetic cloud comprised nearly (33.3%) of the storms while the complex ejecta comprised of about 66.7%. The result shows that the number of magnetic cloud occurrence is nearly double that of complex ejecta. The correlation between Dst and B; and between Dst and Bs was 0.38 and 0.64, respectively for geomagnetic storms resulting from magnetic clouds. The correlation between Dst and B; and between Dst and Bs was 0.43 and 0.53, respectively for geomagnetic storms resulting from complex ejecta. In addition, it was shown that the relationship between the Dst and V for magnetic cloud and complex ejecta was 0.15 and 0.11, respectively. It was observed that the relationship between Dst and VBs for magnetic cloud and complex ejecta were 0.64 and 0.59 respectively. Finally, the present results suggest that though both classes of drivers

  13. Study on the Geomagnetic Short Period Variations of the Northwestern Yunnan

    NASA Astrophysics Data System (ADS)

    Yuan, Y.; Li, Q.; Cai, J.

    2015-12-01

    The Northwestern Yunnan is located in the interaction area between the Eurasian plate and the India plate. This area has been the ideal place for the research of continental dynamics and the prediction for risk region of strong earthquake for its complex tectonic environment and frequent seismic activity. Therefore the study on the geomagnetic short period variations is of great significance in the exploration of deep electrical structure, analysis of the seismic origin and deep geodynamics in the Northwestern Yunnan of China . This paper is based on the geomagnetic data from the magnetometer array with 8 sites built in the northwestern Yunnan to explore the deep electrical structure by the method of geomagnetic depth sounding. Firstly, we selected a total of 183 geomagnetic short period events at the range of 6min to 120min period. And we found a north northwest dividing line, of which two sides has the opposite value in the vertical component variation amplitude, which indicates the obvious conductivity anomaly underground. Secondly, the contour maps of the ratio of vertical component and horizontal component variation amplitude ΔZ/ΔH in different periods reflects the changes of a high conductivity belt's direction and position. In addition, the induction arrows maps within the period of 2 - 256min also shows that on the two sides of the dividing line the induction vectors deviate from each other, and the amplitude and direction of vectors varies with periods regularly. In the light of this, we infer that a high conductivity belt probably exists, which stretches from the deep crust to uppermost mantle and changes with depth constantly with the reference of magnetotelluric sounding. In the end of this paper, the staggered grid finite difference method is used to model the simplified three-dimensional high conductivity anomaly, and the result shows magnetic field distributions are consistent with the observed geomagnetic short period variations characteristics in

  14. Effects of strong geomagnetic storms on Northern railways in Russia

    NASA Astrophysics Data System (ADS)

    Eroshenko, E. A.; Belov, A. V.; Boteler, D.; Gaidash, S. P.; Lobkov, S. L.; Pirjola, R.; Trichtchenko, L.

    2010-11-01

    Seventeen severe magnetic storms occurred in the period 2000 through 2005. In addition there was a major magnetic storm in March 1989. During each of these storms there was an anomaly in the operation of the system of Signalization, Centralization and Blockage (SCB) in some divisions of the high-latitude (˜58 to 64°N) Russian railways. This anomaly was revealed as false traffic light signals about the occupation of the railways. These signals on the Northern railways appeared exactly during the main phases of the strongest part of the geomagnetic storms characterized by high geomagnetic indices Dst and Kp (Ap). Moreover, the durations of these anomalies coincided with the period of the greatest geomagnetic disturbances in a given event. Geomagnetically induced currents (GICs) during significant strengthening of geomagnetic activity are concluded as the obvious reasons for such kind of anomalies.

  15. Development and applications of a unitary group adapted state specific multi-reference coupled cluster theory with internally contracted treatment of inactive double excitations

    NASA Astrophysics Data System (ADS)

    Sinha, Debalina; Maitra, Rahul; Mukherjee, Debashis

    2012-09-01

    Any multi-reference coupled cluster (MRCC) development based on the Jeziorski-Monkhorst (JM) multi-exponential ansatz for the wave-operator Ω suffers from spin-contamination problem for non-singlet states. We have very recently proposed a spin-free unitary group adapted (UGA) analogue of the JM ansatz, where the cluster operators are defined in terms of spin-free unitary generators and a normal ordered, rather than ordinary, exponential parametrization of Ω is used. A consequence of the latter choice is the emergence of the "direct term" of the MRCC equations that terminates at exactly the quartic power of the cluster amplitudes. Our UGA-MRCC ansatz has been utilized to generate both the spin-free state specific (SS) and the state universal MRCC formalisms. It is well-known that the SSMRCC theory requires suitable sufficiency conditions to resolve the redundancy of the cluster amplitudes. In this paper, we propose an alternative variant of the UGA-SSMRCC theory, where the sufficiency conditions are used for all cluster operators containing active orbitals and the single excitations with inactive orbitals, while the inactive double excitations are assumed to be independent of the model functions they act upon. The working equations for the inactive double excitations are thus derived in an internally contracted (IC) manner in the sense that the matrix elements entering the MRCC equations involve excitations from an entire combination of the model functions. We call this theory as UGA-ICID-MRCC, where ICID is the acronym for "Internally Contracted treatment of Inactive Double excitations." Since the number of such excitations are the most numerous, choosing them to be independent of the model functions will lead to very significant reduction in the number of cluster amplitudes for large active spaces, and is worth exploring. Moreover, unlike for the excitations involving active orbitals, where there is inadequate coupling between the model and the virtual functions

  16. Atmospheric helium and geomagnetic field reversals.

    NASA Technical Reports Server (NTRS)

    Sheldon, W. R.; Kern, J. W.

    1972-01-01

    The problem of the earth's helium budget is examined in the light of recent work on the interaction of the solar wind with nonmagnetic planets. It is proposed that the dominant mode of helium (He4) loss is ion pumping by the solar wind during geomagnetic field reversals, when the earth's magnetic field is very small. The interaction of the solar wind with the earth's upper atmosphere during such a period is found to involve the formation of a bow shock. The penetration altitude of the shock-heated solar plasma is calculated to be about 700 km, and ionization rates above this level are estimated for a cascade ionization (electron avalanche) process to average 10 to the 9th power ions/sq cm/sec. The calculated ionization rates and the capacity of the solar wind to remove ionized helium (He4) from the upper atmosphere during geomagnetic dipole reversals are sufficient to yield a secular equilibrium over geologic time scales. The upward transport of helium from the lower atmosphere under these conditions is found to be adequate to sustain the proposed loss rate.

  17. Solar Wind Charge Exchange During Geomagnetic Storms

    NASA Technical Reports Server (NTRS)

    Robertson, Ina P.; Cravens, Thomas E.; Sibeck, David G.; Collier, Michael R.; Kuntz, K. D.

    2012-01-01

    On March 31st. 2001, a coronal mass ejection pushed the subsolar magnetopause to the vicinity of geosynchronous orbit at 6.6 RE. The NASA/GSFC Community Coordinated Modeling Center (CCMe) employed a global magnetohydrodynamic (MHD) model to simulate the solar wind-magnetosphere interaction during the peak of this geomagnetic storm. Robertson et aL then modeled the expected 50ft X-ray emission due to solar wind charge exchange with geocoronal neutrals in the dayside cusp and magnetosheath. The locations of the bow shock, magnetopause and cusps were clearly evident in their simulations. Another geomagnetic storm took place on July 14, 2000 (Bastille Day). We again modeled X-ray emission due to solar wind charge exchange, but this time as observed from a moving spacecraft. This paper discusses the impact of spacecraft location on observed X-ray emission and the degree to which the locations of the bow shock and magnetopause can be detected in images.

  18. Forecasts of solar and geomagnetic activity

    NASA Technical Reports Server (NTRS)

    Joselyn, Joann

    1987-01-01

    Forecasts of solar and geomagnetic activity are critical since these quantities are such important inputs to the thermospheric density models. At this time in the history of solar science there is no way to make such a forecast from first principles. Physical theory applied to the Sun is developing rapidly, but is still primitive. Techniques used for forecasting depend upon the observations over about 130 years, which is only twelve solar cycles. It has been noted that even-numbered cycles systematically tend to be smaller than the odd-numbered ones by about 20 percent. Another observation is that for the last 12 cycle pairs, an even-numbered sunspot cycle looks rather like the next odd-numbered cycle, but with the top cut off. These observations are examples of approximate periodicities that forecasters try to use to achieve some insight into the nature of an upcoming cycle. Another new and useful forecasting aid is a correlation that has been noted between geomagnetic indices and the size of the next solar cycle. Some best estimates are given concerning both activities.

  19. The variations of ionosphere critical frequency of E layer over the equatorial geomagnetic region in Southeast Asia

    NASA Astrophysics Data System (ADS)

    Kenpankho, Prasert; Ishii, Mamoru; Supnithi, Pornchai

    2016-07-01

    We investigate the values of the critical frequency of the ionospheric E layer, foE, obtained at Chumphon ionospheric observatory station, Thailand. For a declining phase of the solar cycle 23 during the year 2005-2008 and an inclining phase of the solar cycle 24 during the year 2009-2013, the foE data have been used to investigate the foE variations over the equatorial geomagnetic region in Southeast Asia. A comparison between the observation data and International Reference Ionosphere (IRI) 2012 model has also been investigated and studied. The results show that the foE obtained from IRI 2012 model underestimates foE from Chumphon station especially during the period of 7-11 am and after 6 pm for each day and all seasons. As the results combining with the previous investigations, we suggest that the underestimation of ionospheric foE by IRI 2012 model is helpful for the correction and improvement of IRI model in an equatorial Asia region.

  20. Study about geomagnetic variations from data recorded at Surlari Geomagnetic Observatory

    NASA Astrophysics Data System (ADS)

    Asimopolos, Laurentiu; Asimopolos, Natalia-Silvia; Sandulescu, Agata Monica; Niculici, Eugen

    2013-04-01

    This paper presents statistical and spectral analysis of data from Surlari Geomagnetic Observatory that contributing to study of geomagnetic variations. Thus were highlighted, for long series of records over several solar cycles, periodicities of 22 years and 11 years. Following the same procedures for medium recording series (multi-annual) have highlighted annual, seasonal and monthly periodicities. For shorter data series, we highlighted diurnal, semidiurnal, 8 hours and even lower periodicities. For very short series with a high sample rate and for few magnetotellurics records, we highlight different types of pulsations (Pc2 - Pc5 and Pi 2). Geomagnetic signals are the convolution product of the atomic stationary signals mono-frequential of different amplitudes associated to phenomena with a very broad band of periodicities and nondeterministic signals associated with geomagnetic disturbances and non-periodic phenomena. Among analysis processes used for discrete series of geomagnetic data with different lengths and sampling rates, can conclude the following: Moving average works as a low pass filter in frequency or high pass in time. By eliminating high frequency components (depending on mobile window size used) can be studied preferential periodicities greater than a given value. Signal linearization (using least squares) provides information on linear trend of the entire series analyzed. Thus, for the very long data series (several decades) we extracted the secular variation slope for each geomagnetic component, separately. The numeric derivative of signal versus time proved to be a very reliable indicator for geomagnetic disturbed periods. Thus, the derivative value may be increased by several orders of magnitude during periods of agitation in comparisons to calm periods. The correlation factor shows significant increases when between two time series a causal relationship exists. Variation of the correlation factor, calculated for a mobile window containing k

  1. Tracking geomagnetic fluctuations to picotesla accuracy using two superconducting quantum interference device vector magnetometers

    SciTech Connect

    Henry, S.; Pozzo di Borgo, E.; Cavaillou, A.

    2013-02-15

    SQUIDs can be used to monitor the three vector components of the geomagnetic field to a high precision at very low frequencies, yet as they are susceptible to external interference, the accuracy to which they can track changes in the dc field over long periods has been unclear. We have carried out simultaneous measurements of the geomagnetic field recorded using two independent 3-axis SQUID magnetometers at the Laboratoire Souterrain a Bas Bruit (LSBB). We demonstrate a technique to take the difference between a linear transform of the three signals from one magnetometer, and a reference signal from the other, in order to account for any difference in alignment and calibration, and track local signals at a sub-nT level. We confirmed that both systems tracked the same signal with an RMS difference as low as 56pT over a period of 72 h. To our knowledge this is the first such demonstration of the long term accuracy of SQUID magnetometers for monitoring geomagnetic fields.

  2. Tracking geomagnetic fluctuations to picotesla accuracy using two superconducting quantum interference device vector magnetometers.

    PubMed

    Henry, S; Pozzo di Borgo, E; Cavaillou, A

    2013-02-01

    SQUIDs can be used to monitor the three vector components of the geomagnetic field to a high precision at very low frequencies, yet as they are susceptible to external interference, the accuracy to which they can track changes in the dc field over long periods has been unclear. We have carried out simultaneous measurements of the geomagnetic field recorded using two independent 3-axis SQUID magnetometers at the Laboratoire Souterrain à Bas Bruit (LSBB). We demonstrate a technique to take the difference between a linear transform of the three signals from one magnetometer, and a reference signal from the other, in order to account for any difference in alignment and calibration, and track local signals at a sub-nT level. We confirmed that both systems tracked the same signal with an RMS difference as low as 56pT over a period of 72 h. To our knowledge this is the first such demonstration of the long term accuracy of SQUID magnetometers for monitoring geomagnetic fields. PMID:23464230

  3. ULF geomagnetic changes possibly associated with the 2008 Iwate-Miyagi Nairiku earthquake

    NASA Astrophysics Data System (ADS)

    Hattori, K.; Hirano, T.

    2009-12-01

    There are many reports on earthquake-related electromagnetic phenomena. Anomalous ULF geomagnetic field changes associated with earthquake is one of the most convincing and promising phenomena due to deeper skin depth. Since ULF signals associated with large earthquakes are weak, effective signal discrimination methods should be required. Several methods for the signal discrimination have been developed so far: which are spectrum density ratio analysis, geomagnetic transfer function analysis, fractal analysis, principal component analysis, direction finding analysis, and so on. In this study, we investigate ULF geomagnetic changes possibly associated with the 2008 Iwate-Miyagi Nairiku earthquake based on spectral density ratio analysis. Geomagnetic data observed at Esashi, where the epicentral distance is about 47 km and Kakioka, the distance is about 317 km, and as a reference station have been analyzed. Wavelet transform have been performed for the spectral density analysis instead of the conventional FFT method. Before the earthquake, the variation of spectral density ratio, Sz/Sx and Sz/Sy, at the nearest station of Esashi exhibits an apparent increase from the trend. On the contrary, there are no corresponding significant changes at a remote station of Kakioka. After investigating the singularity of the increase using normalized spectrum density ratio, the enhancement is the most significant in intensity and duration for the all analyzed period. The level of peak is beyond the 3 sigma and its duration is 3 days. The lead time is about 3-4 weeks before the earthquake. At the periods from 3 to 105 sec, similar anomalous changes occurred. These facts suggest the anomalous change is a possible candidate of earthquake-related ULF magnetic change.

  4. TEC variations during geomagnetic storm/substorm with Pc5/PI2 pulsation signature

    NASA Astrophysics Data System (ADS)

    Hamada, A. M.; Mahrous, A. M.; Fathy, I.; Ghamry, E.; Groves, K.; Yumoto, K.

    2015-06-01

    The electron density integral along the paths between a GPS satellite and receiver is known as Total Electron Content (TEC), and this parameter is used in studying the ionosphere behaviors. TEC can be obtained by means of many methods. A space-based radio navigation system, such as Global Positioning System (GPS), offers good opportunities for studying the ionosphere. The TEC is calculated from the group path delay and phase advance in GPS satellite signals along the slant paths connecting GPS receivers and satellites at 22,000 km. Locally, a dual frequency GPS receiver was installed in Helwan, Egypt (29.86°N, 31.32°E) in November 2009. Here, GPS data were analyzed to establish a daily observation of Vertical TEC in a region located near to the northern crest of the ionospheric equatorial anomaly. During a moderate geomagnetic storm, observed on 02-05 May 2010, a number of ionospheric/magnetic phenomena were observed. Also, observations for Pc5/Pi2 pulsations were recorded during the geomagnetic storm phases. These geomagnetic observations are taken from MAGDAS-magnetometer station, located at Aswan (23.59°N, 32.51°E). More than 10 TECU increase in the ionospheric TEC values were recorded during the daytime of 02 May, followed by a large reduction during 03 May, reference to the pre-storm conditions. This confirms the enhancement in the geomagnetic H-component peak during the storm's initial phase and its reduction during the main phase.

  5. The sensivity of geomagnetic reversal frequency to core-mantle boundary heat flux magnitude and heterogeneity.

    NASA Astrophysics Data System (ADS)

    Metman, Maurits; de Groot, Lennart; Thieulot, Cedric; Biggin, Andrew; Spakman, Wim

    2015-04-01

    For a number of decades the core-mantle boundary (CMB) heat flux has been thought to be a key parameter controlling the geomagnetic field. A CMB heat flow increase is assumed to destabilize the geodynamo, increasing and decreasing the reversal frequency and dipole moment, respectively. The opposite case where a CMB flux decrease induces a relatively high dipole moment, as well as a low reversal frequency, would correspond to the characteristics of a superchron (Biggin et al., 2012). So far, only the magnitude of the CMB heat flux has been subject of research. However, the temporal and spatial heat flux distribution across the CMB also appears to have an influence on the geomagnetic reversal frequency. For example, the amount of heat flux heterogeneity may also be associated with a destabilization of the dynamo, increasing the reversal frequency (Olson et al., 2010). In this work we set out to assess: - (1) How the geomagnetic field intensity and reversals are predominantly sensitive to CMB heat flux magnitude or heterogeneity; - (2) what combination of magnitude and heterogeneity best reproduces the geomagnetic record on the 10 Myr timescale. To this end we use the PARODY software and test for a number of CMB heat flow modes (spherical harmonics of increasing degree and order, with an amplitude of 10 mW/m^2) and magnitudes (ranging from 20 to 100 mW/m^2). We will show our modeling results of how CMB heat flow magnitude and heterogeneity control the paleomagnetic record in terms of reversal frequency and dipole moment. Also relevant snapshots in time of outer core convection and thermal/magnetic structure will be shown. References Biggin et al. (2012). Nature Geoscience, 5(8):526-533. Olson et al. (2010). PEPI, 180(1-2):66 - 79.

  6. Ionospheric, protonospheric and total electron content in quiet geomagnetic conditions and during geomagnetic storm

    NASA Astrophysics Data System (ADS)

    Nosikov, Igor; Klimenko, Maxim; Klimenko, Vladimir

    This report presents the results of studies the ionospheric, plasmaspheric and total electron content during recent minimum of solar activity in quiet geomagnetic condition and for geomagnetic storm on 26 September 2011. A comparison of the calculation results obtained using the GSM TIP model, with observational data of the mid- and high-latitude ionospheric sounding stations, as well as estimation of the plasmaspheric reservoir contribution into the total electron content obtained from GPS TEC measurements, COSMIC radio-occultation experiment and incoherent scatter radars were presented. The particular attention is given to the global distribution of the O+/H+ transition height in order to determine the top and low boundary for ionospheric and protonospheric electron content, respectively. This work was supported by Grant of Russian President №МК-4866.2014.5, №14-05-00578, and Program 22 RAS.

  7. Is motivation influenced by geomagnetic activity?

    PubMed

    Starbuck, S; Cornélissen, G; Halberg, F

    2002-01-01

    To eventually build a scientific bridge to religion by examining whether non-photic, non-thermic solar effects may influence (religious) motivation, invaluable yearly world wide data on activities from 1950 to 1999 by Jehovah's Witnesses on behalf of their church were analyzed chronobiologically. The time structure (chronome) of these archives, insofar as it is able to be evaluated in yearly means for up to half a century, was assessed. Least squares spectra in a frequency range from one cycle in 42 to one in 2.1 years of data on the average number of hours per month spent in work for the church, available from 103 different geographic locations, as well as grand totals also including other sites, revealed a large peak at one cycle in about 21 years. The non-linear least squares fit of a model consisting of a linear trend and a cosine curve with a trial period of 21.0 years, numerically approximating that of the Hale cycle, validated the about 21.0-year component in about 70% of the data series, with the non-overlap of zero by the 95% confidence interval of the amplitude estimate. Estimates of MESOR (midline-estimating statistic of rhythm, a rhythm (or chronome) adjusted mean), amplitude and period were further regressed with geomagnetic latitude. The period estimate did not depend on geomagnetic latitude. The about 21.0-year amplitude tends to be larger at low and middle than at higher latitudes and the resolution of the about 21.0-year cycle, gauged by the width of 95% confidence intervals for the period and amplitude, is higher (the 95% confidence intervals are statistically significantly smaller) at higher than at lower latitudes. Near-matches of periods in solar activity and human motivation hint that the former may influence the latter, while the dependence on latitude constitutes evidence that geomagnetic activity may affect certain brain areas involved in motivation, just as it was earlier found that it is associated with effects on the electrocardiogram

  8. Using the International Classification of Functioning, Disability and Health (ICF) to Describe Children Referred to Special Care or Paediatric Dental Services

    PubMed Central

    Faulks, Denise; Norderyd, Johanna; Molina, Gustavo; Macgiolla Phadraig, Caoimhin; Scagnet, Gabriela; Eschevins, Caroline; Hennequin, Martine

    2013-01-01

    Children in dentistry are traditionally described in terms of medical diagnosis and prevalence of oral disease. This approach gives little information regarding a child’s capacity to maintain oral health or regarding the social determinants of oral health. The biopsychosocial approach, embodied in the International Classification of Functioning, Disability and Health - Child and Youth version (ICF-CY) (WHO), provides a wider picture of a child’s real-life experience, but practical tools for the application of this model are lacking. This article describes the preliminary empirical study necessary for development of such a tool - an ICF-CY Core Set for Oral Health. An ICF-CY questionnaire was used to identify the medical, functional, social and environmental context of 218 children and adolescents referred to special care or paediatric dental services in France, Sweden, Argentina and Ireland (mean age 8 years ±3.6yrs). International Classification of Disease (ICD-10) diagnoses included disorders of the nervous system (26.1%), Down syndrome (22.0%), mental retardation (17.0%), autistic disorders (16.1%), and dental anxiety alone (11.0%). The most frequently impaired items in the ICF Body functions domain were ‘Intellectual functions’, ‘High-level cognitive functions’, and ‘Attention functions’. In the Activities and Participation domain, participation restriction was frequently reported for 25 items including ‘Handling stress’, ‘Caring for body parts’, ‘Looking after one’s health’ and ‘Speaking’. In the Environment domain, facilitating items included ‘Support of friends’, ‘Attitude of friends’ and ‘Support of immediate family’. One item was reported as an environmental barrier – ‘Societal attitudes’. The ICF-CY can be used to highlight common profiles of functioning, activities, participation and environment shared by children in relation to oral health, despite widely differing medical, social and geographical

  9. D'Entrecasteaux, 1792: Celebrating a bicentennial in geomagnetism

    NASA Astrophysics Data System (ADS)

    Lilley, F. E. M. (Ted); Day, Alan A.

    The first surveys of global magnetic intensity, and especially the demonstration of its variation with latitude, are commonly credited (for example, Chapman, [1967]) to Alexander Von Humboldt, who played a major role in developing geomagnetism in the late 18th and 19th centuries. Von Humboldt made intensity measurements in South America from 1798-1803 and later encouraged the establishment of a global magnetic observatory network (see, for example, Malin and Barraclough, [1991]).However, as pointed out by Sabine [1838] in a review of intensity measurements to that time, the earliest surviving survey of global magnetic intensity, showing it to strengthen away from the equator both north and south, was made by Elisabeth Paul Edouard De Rossel during the 1791-1794 expedition of Bruny D'Entrecasteaux. Even earlier measurements seem certain to have been made by the scientist Robert de Paul, chevalier de Lamanon (always referred to as Lamanon) of the La Pérouse expedition [Milet-Mureau, 1799], but any records are evidently lost. Lamanon died when the La Pérouse expedition was in Samoa in 1797, and both ships of that expedition were wrecked on the island of Vanikoro, presumably in 1788 [Marchant, 1967; Spate, 1988]. All such measurements were of relative magnetic intensity until a method for the determination of absolute intensity was invented by Gauss in 1832. For a recent discussion of this latter topic, see Jackson [1992].

  10. Studies on the Geomagnetic Induction Vectors of China

    NASA Astrophysics Data System (ADS)

    Wang, Qiao; Zhang, Huiqian; Huang, Qinghua

    2016-04-01

    In this study, the geomagnetic data of 16 stations, near 6 years for most, provided by the National Geomagnetic Center of China, were used to study on the geomagnetic induction vectors. The stations cover the whole North China and part of southwestern China, both of which has a complicate geological and tectonic background. This study will not only advance the understanding of regional tectonic variations, but also provide some suggestions on the construction for geomagnetic observation network of earthquake monitoring. The time series of geomagnetic induction vectors were obtained by the robust estimation method, which has been verified and compared with the ordinary least square and the weighted square method. A principle of selecting a specified period's results from the robust estimation method was defined. Then, the results with the period of 640s for all stations were selected by this principle. The long-term trends (more than six months at least) within the time series were extracted by the Fourier harmonic analysis. Consistent phase variations exist for most stations within a similar tectonic background. About one-month period variations in the most stations' results after removing the long-term trends were found. Spectrum analysis for the results and geomagnetic activity index showed that those phenomena may relate to the period of the global geomagnetic activity. A preference azimuth of the geomagnetic induction vectors was found in each station by statistical analysis on the time series. It pointed out the possible relatively high conductivity structures. Exactly, geomagnetic vectors of BJI, JIH, LYH and TAY station, which surround the basin of North China, suggested a relatively higher conductivity layer; that of stations around the Erdos block suggested a complicated structure. Three-dimension inversion by ModEM verifies our results.

  11. Validation of Internal Reference Genes for Real-Time Quantitative Polymerase Chain Reaction Studies in the Tick, Ixodes scapularis (Acari: Ixodidae)

    PubMed Central

    Koči, Juraj; Šimo, Ladislav; Park, Yoonseong

    2013-01-01

    Obtaining reliable gene expression data using real-time quantitative polymerase chain reaction(qPCR)is highly dependent on the choice of normalization method. We tested the expression stability of multiple candidate genes in the salivary glands (SG) and synganglia (SYN) of female Ixodes scapularis (Say) ticks in multiple blood-feeding phases. We found that the amount of total RNA in both the SG and SYN increases dramatically during tick feeding, with 34× and 5.8× increases from 62 and 7.1 ng of unfed tick, respectively. We tested candidate genes that were predicted from I. scapularis genome data to encode glyceraldehyde 3-phosphate dehydrogenase (gapdh), ribosomal protein L13A (l13a), TATA box-binding protein (tbp), ribosomal protein S4 (rps4), glucose 6-phosphate dehydrogenase (gpdh), and beta-glucuronidase (gusb). The geNorm and NormFinder algorithms were used to analyze data from different feeding phases (i.e., daily samples from unfed to fully engorged females over a 7-d period in three replicate experiments). We found that the rps4 and l13a genes showed highly stable expression patterns over the feeding duration in both the SG and SYN. Furthermore, the highly expressed rps4 gene makes it useful as a normalization factor when we perform studies using minute amounts of dissected tissue for qPCR. We conclude that rps4 and l13a, whether individually or as a pair, serve as suitable internal reference genes for qRT-PCR studies in the SG and SYN of I. scapularis. PMID:23427655

  12. Fundamental discrepancies in abortion estimates and abortion-related mortality: A reevaluation of recent studies in Mexico with special reference to the International Classification of Diseases

    PubMed Central

    Koch, Elard; Aracena, Paula; Gatica, Sebastián; Bravo, Miguel; Huerta-Zepeda, Alejandra; Calhoun, Byron C

    2012-01-01

    In countries where induced abortion is legally restricted, as in most of Latin America, evaluation of statistics related to induced abortions and abortion-related mortality is challenging. The present article reexamines recent reports estimating the number of induced abortions and abortion-related mortality in Mexico, with special reference to the International Classification of Diseases (ICD). We found significant overestimations of abortion figures in the Federal District of Mexico (up to 10-fold), where elective abortion has been legal since 2007. Significant overestimation of maternal and abortion-related mortality during the last 20 years in the entire Mexican country (up to 35%) was also found. Such overestimations are most likely due to the use of incomplete in-hospital records as well as subjective opinion surveys regarding induced abortion figures, and due to the consideration of causes of death that are unrelated to induced abortion, including flawed denominators of live births. Contrary to previous publications, we found important progress in maternal health, reflected by the decrease in overall maternal mortality (30.6%) from 1990 to 2010. The use of specific ICD codes revealed that the mortality ratio associated with induced abortion decreased 22.9% between 2002 and 2008 (from 1.48 to 1.14 deaths per 100,000 live births). Currently, approximately 98% of maternal deaths in Mexico are related to causes other than induced abortion, such as hemorrhage, hypertension and eclampsia, indirect causes, and other pathological conditions. Therefore, only marginal or null effects would be expected from changes in the legal status of abortion on overall maternal mortality rates. Rather, maternal health in Mexico would greatly benefit from increasing access to emergency and specialized obstetric care. Finally, more reliable methodologies to assess abortion-related deaths are clearly required. PMID:23271925

  13. Fundamental discrepancies in abortion estimates and abortion-related mortality: A reevaluation of recent studies in Mexico with special reference to the International Classification of Diseases.

    PubMed

    Koch, Elard; Aracena, Paula; Gatica, Sebastián; Bravo, Miguel; Huerta-Zepeda, Alejandra; Calhoun, Byron C

    2012-01-01

    In countries where induced abortion is legally restricted, as in most of Latin America, evaluation of statistics related to induced abortions and abortion-related mortality is challenging. The present article reexamines recent reports estimating the number of induced abortions and abortion-related mortality in Mexico, with special reference to the International Classification of Diseases (ICD). We found significant overestimations of abortion figures in the Federal District of Mexico (up to 10-fold), where elective abortion has been legal since 2007. Significant overestimation of maternal and abortion-related mortality during the last 20 years in the entire Mexican country (up to 35%) was also found. Such overestimations are most likely due to the use of incomplete in-hospital records as well as subjective opinion surveys regarding induced abortion figures, and due to the consideration of causes of death that are unrelated to induced abortion, including flawed denominators of live births. Contrary to previous publications, we found important progress in maternal health, reflected by the decrease in overall maternal mortality (30.6%) from 1990 to 2010. The use of specific ICD codes revealed that the mortality ratio associated with induced abortion decreased 22.9% between 2002 and 2008 (from 1.48 to 1.14 deaths per 100,000 live births). Currently, approximately 98% of maternal deaths in Mexico are related to causes other than induced abortion, such as hemorrhage, hypertension and eclampsia, indirect causes, and other pathological conditions. Therefore, only marginal or null effects would be expected from changes in the legal status of abortion on overall maternal mortality rates. Rather, maternal health in Mexico would greatly benefit from increasing access to emergency and specialized obstetric care. Finally, more reliable methodologies to assess abortion-related deaths are clearly required. PMID:23271925

  14. Stochastic resonance in geomagnetic polarity reversals.

    PubMed

    Consolini, Giuseppe; De Michelis, Paola

    2003-02-01

    Among noise-induced cooperative phenomena a peculiar relevance is played by stochastic resonance. In this paper we offer evidence that geomagnetic polarity reversals may be due to a stochastic resonance process. In detail, analyzing the distribution function P(tau) of polarity residence times (chrons), we found the evidence of a stochastic synchronization process, i.e., a series of peaks in the P(tau) at T(n) approximately (2n+1)T(Omega)/2 with n=0,1,...,j and T(omega) approximately 0.1 Myr. This result is discussed in connection with both the typical time scale of Earth's orbit eccentricity variation and the recent results on the typical time scale of climatic long-term variation. PMID:12633403

  15. Solar wind turbulence as a driver of geomagnetic activity

    NASA Astrophysics Data System (ADS)

    Ikechukwu Ugwu, Ernest Benjamin; Nneka Okeke, Francisca; Ugonabo, Obiageli Josephine

    2016-07-01

    We carried out simultaneous analyses of interplanetary and geomagnetic datasets for the period of (solar Maunder) least (2009) and maximum (2002) solar activity to determine the nature of solar wind turbulence on geomagnetic activity using AE, ASY-D, and ASY-H indices. We determined the role played by Alfvénic fluctuations in the solar wind so as to find out the nature of the turbulence. Our analyses showed that solar wind turbulence play a role in geomagnetic processes at high latitudes during periods of low and high solaractivity but does not have any effect at mid-low latitudes.

  16. Search for correlation between geomagnetic disturbances and mortality

    NASA Technical Reports Server (NTRS)

    Lipa, B. J.; Sturrock, P. A.; Rogot, F.

    1976-01-01

    A search is conducted for a possible correlation between solar activity and myocardial infarction and stroke in the United States. A statistical analysis is performed using data on geomagnetic activity and the daily U.S. mortality due to coronary heart disease and stroke for the years 1962 through 1966. None of the results are found to yield any evidence of a correlation. It is concluded that correlations claimed by Soviet workers between geomagnetic activity and the incidence of various human diseases are probably not statistically significant or probably are not due to a causal relation between geomagnetic activity and disease.

  17. Geomagnetic storms: Potential economic impacts on electric utilities

    SciTech Connect

    Barnes, P.R.; Van Dyke, J.W.

    1991-03-20

    Geomagnetic storms associated with sunspot and solar flare activity can disturb communications and disrupt electric power. A very severe geomagnetic storm could cause a major blackout with an economic impact of several billion dollars. The vulnerability of electric power systems in the northeast United States will likely increase during the 1990s because of the trend of transmitting large amounts of power over long distance to meet the electricity demands of this region. A comprehensive research program and a warning satellite to monitor the solar wind are needed to enhance the reliability of electric power systems under the influence of geomagnetic storms. 7 refs., 2 figs., 1 tab.

  18. Geomagnetic field fluctuations at synchronous orbit. II - Radial diffusion

    NASA Technical Reports Server (NTRS)

    Lanzerotti, L. J.; Webb, D. C.; Arthur, C. W.

    1978-01-01

    Power spectra of geomagnetic-field variations measured at synchronous equatorial altitude (geomagnetic shell parameter about 6.6) in the magnetosphere are used to calculate the time dependence of the radial diffusion coefficient for particles in the radiation belts. The diffusion coefficients calculated are mainly applicable for relativistic electrons. The magnitudes of the derived diffusion coefficients using data only from local day observations are consistent with those reported from analyses of most particle observations and thus are slightly larger than those derived from magnetic sudden commencements. They are consistent with the diffusion coefficients calculated from power spectra of ground-based geomagnetic data measured near L = 4.

  19. Historical records of the geomagnetic field

    NASA Astrophysics Data System (ADS)

    Arneitz, Patrick; Heilig, Balázs; Vadasz, Gergely; Valach, Fridrich; Dolinský, Peter; Hejda, Pavel; Fabian, Karl; Hammerl, Christa; Leonhardt, Roman

    2014-05-01

    Records of historical direct measurements of the geomagnetic field are invaluable sources to reconstruct temporal variations of the Earth's magnetic field. They provide information about the field evolution back to the late Middle Age. We have investigated such records with focus on Austria and some neighbouring countries. A variety of new sources and source types are examined. These include 19th century land survey and observatory records of the Imperial and Royal "Centralanstalt f. Meteorologie und Erdmagnetismus", which are not included in the existing compilations. Daily measurements at the Imperial and Royal Observatory in Prague have been digitized. The Imperial and Royal Navy carried out observations in the Adriatic Sea during several surveys. Declination values have been collected from famous mining areas in the former Austro-Hungarian Empire. In this connection, a time series for Banska Stiavnica has been compiled. In the meteorological yearbooks of the monastery Kremsmünster regular declination measurements for the first half of the 19th century were registered. Marsigli's observations during military mapping works in 1696 are also included in our collection. Moreover, compass roses on historical maps or declination values marked on compasses, sundials or globes also provide information about ancient field declination. An evaluation of church orientations in Lower Austria and Northern Germany did not support the hypothesis that church naves had been aligned along the East-West direction by means of magnetic compasses. Therefore, this potential source of information must be excluded from our collection. The gathered records are integrated into a database together with corresponding metadata, such as the used measurement instruments and methods. This information allows an assessment of quality and reliability of the historical observations. The combination of compilations of historical measurements with high quality archeo- and paleomagnetic data in a

  20. Two thousand years of geomagnetic field direction over central Europe revealed by indirect measurements

    NASA Astrophysics Data System (ADS)

    Márton, Péter

    2010-04-01

    Supplemented by 32 new directions, the Hungarian archaeomagnetic data set now consists of 217 archaeologically dated directions ranging in age from 300 BC to 1800 AD. From this data set, reference curves of secular variation of the geomagnetic field direction were computed using hierarchical modelling and curve estimation by moving average technique. Thanks to some of the new data, the gap in the earlier reference curves around 500 AD has now been filled up. For comparison's sake, directional records of comparable length from central Europe were also processed by the same curve building method. For this purpose, all dated directional data (declination and inclination with statistics) were drawn from the GEOMAGIA50 database for France, Germany, the Ukraine and Moldavia, Bulgaria and Italy and transferred via their virtual geomagnetic poles to a reference point of their respective countries. The resulting reference curves, including those for Hungary, show more or less similar temporal behaviour to the corresponding CALS7K.2 model curves (also available from the GEOMAGIA50 database), but significant deviations from the low-order CALS7K.2 predictions are also discernible owing to the likely presence of additional higher-order complications in the regional field. Therefore, the regional field and its secular variation are suggested to be approximated by the reference rather than the predicted curves. At any other location within the study area, the direction of the regional field can be obtained by spatial interpolation from the reference curves as illustrated by isogonic and isoclinic maps shown for selected times. Local time-series of interpolated directions for other central European countries lacking reference curves might serve as master curves for magnetic dating.

  1. Magnetic Flux Transport and Pressure Variations at Magnetotail Plasma Flow Bursts during Geomagnetically Quiet Times

    NASA Astrophysics Data System (ADS)

    Nowada, M.; Fu, S.-Y.; Parks, G. K.; Pu, Z.-Y.; Angelopoulos, V.; Carlson, C. W.; Auster, H.-U.

    2012-04-01

    of the magnetic flux was transported into the parallel and perpendicular directions to the local magnetic field line than the dawn-dusk direction at the flow bursts. However, in the Ey component, the contribution from the dawn-to-dusk electric field (VxBz) was much greater than that from the dusk-to-dawn component (VzBx). Furthermore, for two events, significant reduction of the plasma pressure, and enhancement of the north-south magnetic field component (Bz) were observed at/near the flow bursts. Simultaneous total pressure was well-balanced, indicating that the magnetotail during the plasma flow bursts was in the state of equilibrium. Based on these results, "bubble" might play a crucial role for generating the plasma flow bursts at geomagnetically quiet times. Reference: Nowada, M., S. -Y. Fu, G. K. Parks, Z. -Y. Pu, V. Angelopoulos, C. W. Carlson, H. -U. Auster (2012), Plasma flow bursts in the magnetotail during geomagnetically quiet times 2: Relation to the magnetic reconnection and substorm process, to be submitted to Journal of Geophysical Research -Space Physics-. Corresponding Author : Motoharu Nowada nowada@pku.edu.cn

  2. The Longitudinal Interplay of Students' Academic Self-Concepts and Achievements within and across Domains: Replicating and Extending the Reciprocal Internal/External Frame of Reference Model

    ERIC Educational Resources Information Center

    Niepel, Christoph; Brunner, Martin; Preckel, Franzis

    2014-01-01

    Students' cognitive and motivational profiles have a large impact on their academic careers. The development of such profiles can partly be explained by the reciprocal internal/external frame of reference model (RI/E model). The RI/E model predicts positive and negative longitudinal effects between academic self-concepts and achievements…

  3. Complete Genome Sequences of Dengue Virus Type 1 to 4 Strains Used for the Development of CBER/FDA RNA Reference Reagents and WHO International Standard Candidates for Nucleic Acid Testing

    PubMed Central

    Añez, Germán; Heisey, Daniel A.; Volkova, Evgeniya

    2016-01-01

    Dengue virus (DENV), a member of the Flaviviridae family, is the most common and clinically significant arbovirus in the world and is endemic in more than 100 countries. Here, we report the complete sequences of four DENV serotypes used in the development of the CBER/FDA RNA reference reagents and WHO International Standard candidates for nucleic acid testing. PMID:26868382

  4. Vertical total electron content and geomagnetic perturbations at mid- and sub-auroral southern latitudes during geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Meza, Amalia; Andrea van Zele, María; Claudio, Brunini; Rosalía Cabassi, Iris

    2005-03-01

    Several new space geodesy techniques allow us to analyze the behavior of the vertical total electron content (VTEC) with high spatial and temporal resolution. This study is based on the VTEC computed from global positioning system (GPS) satellite signals that are recorded from observatories located at mid- and sub-auroral southern latitudes. The geomagnetic disturbances are analyzed using the Dst and AL geomagnetic indices and geomagnetic field variations which are recorded from an observatory close to one of the GPS stations and from observatories located at equivalent geomagnetic latitudes but in the Northern Hemisphere. The study is focused on two consecutive geomagnetic storms, which happened on October 4 and 5, 2000, characterized by two flips of the interplanetary magnetic field. During this perturbed period, the substorms are evidenced by the AL index and by the field variations recorded by the geomagnetic observatories. We also analyze a substorm effect that occurred during a geomagnetic storm. Variations in f0F2 are currently considered to study the geomagnetic storm effects on the ionosphere. Our results show that at mid- and subauroral southern latitudes the behavior of the VTEC evidences the “dusk” effect (positive ionospheric storm after noon) in a similar way to f0F2 variations. Similar geomagnetic conditions can be inferred from the Dst index for both geomagnetic storms but a quick rise of the VTEC and the dusk effect is only observed on the first stormy day. The positive ionospheric storm is followed by a negative phase that lasts until October 6. The second geomagnetic storm starts when the negative phase of the first ionospheric storm is still deployed and the ionosphere/plasmasphere system conditions do not allow a new positive ionospheric storm. The AL index and the geomagnetic field variations allow us to recognize the expansion phase of the substorm due to the presence of the electromagnetic wedge that couples the magnetosphere and

  5. Interplanetary magnetic sector polarity inferred from polar geomagnetic field observations

    NASA Technical Reports Server (NTRS)

    Eriss-Christensen, E.; Lassen, K.; Wilcox, J. M.; Gonzalez, W.; Colburn, D. S.

    1971-01-01

    With the use of a prediction technique it is shown that the polarity (toward or away from the sun) of the interplanetary magnetic field can be reliably inferred from observations of the polar geomagnetic field.

  6. Estimation of interplanetary electric field conditions for historical geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Kumar, Sandeep; Veenadhari, B.; Tulasi Ram, S.; Selvakumaran, R.; Mukherjee, Shyamoli; Singh, Rajesh; Kadam, B. D.

    2015-09-01

    Ground magnetic measurements provide a unique database in understanding space weather. The continuous geomagnetic records from Colaba-Alibag observatories in India contain historically longest and continuous observations from 1847 to present date. Some of the super intense geomagnetic storms that occurred prior to 1900 have been revisited and investigated in order to understand the probable interplanetary conditions associated with intense storms. Following Burton et al. (1975), an empirical relationship is derived for estimation of interplanetary electric field (IEFy) from the variations of Dst index and ΔH at Colaba-Alibag observatories. The estimated IEFy values using Dst and ΔHABG variations agree well with the observed IEFy, calculated using Advanced Composition Explorer (ACE) satellite observations for intense geomagnetic storms in solar cycle 23. This study will provide the uniqueness of each event and provide important insights into possible interplanetary conditions for intense geomagnetic storms and probable frequency of their occurrence.

  7. Magnetospheric Energy Input during Intense Geomagnetic Storms in SC23

    NASA Astrophysics Data System (ADS)

    Besliu-Ionescu, Diana; Maris Muntean, Georgeta; Dobrica, Venera; Mierla, Marilena

    2015-04-01

    Geomagnetic storm connections to solar eruptive phenomena in solar cycle 23 (SC23) have been intensively studied and it is a subject of great importance because of their various effects in our day-to-day life. We analyse the energy transfer from the solar wind into the magnetosphere during intense geomagnetic storms defined by Dst ≤ -150 nT. There were 29 intense storms during SC23. We will use the Akasofu parameter (Akasofu, 1981) to compute the ɛ function and study its time profile. We compute the energy input efficiency during the main phase of the geomagnetic storm. We compute the magnetospheric energy input using the formula introduced by Wang et al. (2014) and compare these results with the ɛ function for the geomagnetic storms of October 29-30, 2003.

  8. Studying geomagnetic pulsation characteristics with the local approximation method

    NASA Astrophysics Data System (ADS)

    Getmanov, V. G.; Dabagyan, R. A.; Sidorov, R. V.

    2016-03-01

    A local approximation method based on piecewise sinusoidal models has been proposed in order to study the frequency and amplitude characteristics of geomagnetic pulsations registered at a network of magnetic observatories. It has been established that synchronous variations in the geomagnetic pulsation frequency in the specified frequency band can be studied with the use of calculations performed according to this method. The method was used to analyze the spectral-time structure of Pc3 geomagnetic pulsations registered at the network of equatorial observatories. Local approximation variants have been formed for single-channel and multichannel cases of estimating the geomagnetic pulsation frequency and amplitude, which made it possible to decrease estimation errors via filtering with moving weighted averaging.

  9. A comprehensive analysis of the geomagnetic storms occurred dur

    NASA Astrophysics Data System (ADS)

    Ghamry, Essam; Lethy, Ahmed; Arafa-Hamed, Tareq; Abd Elaal, Esmat

    2016-06-01

    The Geomagnetic storms are considered as one of the major natural hazards. Egyptian geomagnetic observatories observed multiple geomagnetic storms during 18 February to 2 March 2014. During this period, four interplanetary shocks successively hit the Earth's magnetosphere, leading to four geomagnetic storms. The storm onsets occurred on 18, 20, 23 and 27 February. A non-substorm Pi2 pulsation was observed on 26 February. This Pi2 pulsation was detected in Egyptian observatories (Misallat and Abu Simbel), Kakioka station in Japan and Carson City station in US with nearly identical waveforms. Van Allen Probe missions observed non-compressional Pc4 pulsations on the recovery phase of the third storm. This Pc4 event is may be likely attributed to the decay of the ring current in the recovery phase.

  10. Geomagnetic field variations in seismic waves traveling across a fault

    NASA Astrophysics Data System (ADS)

    Lukishov, B. G.; Spivak, A. A.; Ter-Semenov, A. A.

    2012-01-01

    The results of regular instrumental observations over geomagnetic field variations in the zones of influence of tectonic faults during movement of seismic waves of varied intensity are presented. It has been shown that seismic waves with an amplitude more than 5-10 μm/s, traveling across the fault zone, always produced geomagnetic field variations. At weaker seismic disturbances, geomagnetic field variations are of the "glimmer" character, and the relative frequency of appearance of the effect drops as the seismic wave amplitude decreases. The quantitative dependence between the maximal value of the full vector of variations in geomagnetic field induction in a fault zone and the amplitude of the seismic disturbance has been found for the first time.

  11. A prediction of geomagnetic activity for solar cycle 23

    NASA Astrophysics Data System (ADS)

    Cliver, E. W.; Ling, A. G.; Wise, J. E.; Lanzerotti, L. J.

    1999-04-01

    Using a database of 13 solar cycles of geomagnetic aa data, we obtained correlations between cycle averages of geomagnetic activity (and sunspot number) and the numbers of days with disturbance levels above certain aa thresholds. We then used a precursor-type relation to predict an average aa index of 23.1 nT for cycle 23 and inserted this average aa value into the above correlations to forecast the integral size distribution of geomagnetic activity for the new cycle. The predicted size distribution is similar to that observed for cycles 21 and 22 but most closely resembles that of solar cycle 18 (1944-1954), which was slightly smaller than cycles 21 and 22. Our prediction agrees reasonably well with the ``climatology-based'' forecast made by the intergovernmental panel tasked to predict geomagnetic activity for the coming solar cycle and is significantly different from their ``precursor-based'' prediction.

  12. Study of Fractal Features of Geomagnetic Activity Through an MHD Shell Model

    NASA Astrophysics Data System (ADS)

    Dominguez, M.; Nigro, G.; Munoz, V.; Carbone, V.

    2013-12-01

    Studies on complexity have been of great interest in plasma physics, because they provide new insights and reveal possible universalities on issues such as geomagnetic activity, turbulence in laboratory plasmas, physics of the solar wind, etc. [1, 2]. In particular, various studies have discussed the relationship between the fractal dimension, as a measure of complexity, and physical processes in magnetized plasmas such as the Sun's surface, the solar wind and the Earth's magnetosphere, including the possibility of forecasting geomagnetic activity [3, 4, 5]. Shell models are low dimensional dynamical models describing the main statistical properties of magnetohydrodynamic (MHD) turbulence [6]. These models allow us to describe extreme parameter conditions hence reaching very high Reynolds (Re) numbers. In this work a MHD shell model is used to describe the dissipative events which are taking place in the Earth's magnetosphere and causing geomagnetic storms. The box-counting fractal dimension (D) [7] is calculated for the time series of the magnetic energy dissipation rate obtained in this MHD shell model. We analyze the correlation between D and the energy dissipation rate in order to make a comparison with the same analysis made on the geomagnetic data. We show that, depending on the values of the viscosity and the diffusivity, the fractal dimension and the occurrence of bursts exhibit correlations similar as those observed in geomagnetic and solar data, [8] suggesting that the latter parameters could play a fundamental role in these processes. References [1] R. O. Dendy, S. C. Chapman, and M. Paczuski, Plasma Phys. Controlled Fusion 49, A95 (2007). [2] T. Chang and C. C. Wu, Phys. Rev. E 77, 045401 (2008). [3] R. T. J. McAteer, P. T. Gallagher, and J. Ireland, Astrophys. J. 631, 628 (2005). [4] V. M. Uritsky, A. J. Klimas, and D. Vassiliadis, Adv. Space Res. 37, 539 (2006). [5] S. C. Chapman, B. Hnat, and K. Kiyani, Nonlinear Proc. Geophys. 15, 445 (2008). [6] G

  13. The Geomagnetic Field and Radiation in Near-Earth Orbits

    NASA Technical Reports Server (NTRS)

    Heirtzler, J. R.

    1999-01-01

    This report shows, in detail, how the geomagnetic field interacts with the particle flux of the radiation belts to create a hazard to spacecraft and humans in near-Earth orbit. It illustrates the geometry of the geomagnetic field lines, especially around the area where the field strength is anomalously low in the South Atlantic Ocean. It discusses how the field will probably change in the future and the consequences that may have on hazards in near space.

  14. Geomagnetic disturbance and the orientation of nocturnally migrating birds.

    PubMed

    Moore, F R

    1977-05-01

    Free-flying passerine migrants respond to natural fluctuations in the earth's magnetic field. The variability in flight directions of nocturnal migrants is significantly correlated with increasing geomagnetic disturbance as measured by both the K index and various components of the earth's magnetic field. The results indicate that such disturbances influence the orientation of free-flying migrants, but the evidence is not sufficient to show that geomagnetism is a cue in their orientation system. PMID:854743

  15. Detection and characterization of geomagnetic pulsations using HF ionospheric heating

    SciTech Connect

    Lee, H.S.; Ferraro, A.J.; Olson, J.V. Alaska Univ., Fairbanks )

    1990-12-01

    This paper describes the geomagnetic pulsations observed in the high-latitude ionosphere during an experiment dealing with the ionospheric generation of ELF/VLF EM waves in June and October 1987. There was clear evidence of geomagnetic pulsations intermixed with the ELF/VLF signals in both the magnitude and phase data. A simple simulation model is introduced to facilitate the interpretation of the data, and a procedure for characterizing the pulsation is described. 5 refs.

  16. Dependence of geosynchronous relativistic electron enhancements on geomagnetic parameters

    NASA Astrophysics Data System (ADS)

    Dmitriev, A. V.; Chao, J. K.

    2003-11-01

    Relativistic electron fluxes observed in geosynchronous orbit by GOES-8 in 1997 to 2000 were considered as a complex function of geomagnetic indices PC, Kp, and Dst, as well as parameters of the magnetosphere size, subsolar Rs, and terminator Rf magnetopause distances. A geosynchronous relativistic electron enhancement (GREE) is determined as daily maximal electron flux exceeding the upper root mean square deviation (RMSD) threshold of about 1500 (cm2s sr)-1. Comparison analysis of the GREE dynamics and geomagnetic conditions on the rising phase of current solar cycle revealed suppression of the relativistic electron enhancements by substantially increased strong geomagnetic activity in the solar maximum. Statistical consideration of a relationship between the GREEs and the geomagnetic parameters showed that the most important parameters controlling the geosynchronous relativistic electron enhancements were 4-day averaged Kp index, PC index, and magnetopause termination distance Rf, delayed on 3 and 14 hours, respectively. Relatively high averaging time for Kp was explained by the cumulative effect of substorm energy release in a gradual mechanism accelerating the relativistic electrons in the magnetosphere. Very short time delay for PC index was interpreted as intensification of a fast acceleration mechanism producing the GREEs during severe geomagnetic storms. Substantial increase of the PC index (PC > 5) was found to be a sufficient condition for GREE occurrence. The fast response of the geosynchronous relativistic electron fluxes on the magnetosphere compression was explained by drift losses of the energetic electrons at the magnetopause, which approaches the Earth during geomagnetic storms.

  17. Automated detection of geomagnetic storms with heightened risk of GIC

    NASA Astrophysics Data System (ADS)

    Bailey, Rachel L.; Leonhardt, Roman

    2016-06-01

    Automated detection of geomagnetic storms is of growing importance to operators of technical infrastructure (e.g., power grids, satellites), which is susceptible to damage caused by the consequences of geomagnetic storms. In this study, we compare three methods for automated geomagnetic storm detection: a method analyzing the first derivative of the geomagnetic variations, another looking at the Akaike information criterion, and a third using multi-resolution analysis of the maximal overlap discrete wavelet transform of the variations. These detection methods are used in combination with an algorithm for the detection of coronal mass ejection shock fronts in ACE solar wind data prior to the storm arrival on Earth as an additional constraint for possible storm detection. The maximal overlap discrete wavelet transform is found to be the most accurate of the detection methods. The final storm detection software, implementing analysis of both satellite solar wind and geomagnetic ground data, detects 14 of 15 more powerful geomagnetic storms over a period of 2 years.

  18. [Relation between microcirculation parameters and Pc3 geomagnetic pulsations].

    PubMed

    Zenchehko, T A; Poskotinova, L V; Rekhtina, A G; Zaslavskaia, R M

    2010-01-01

    An individual analysis of long-term monitoring of microcirculation parameters of nine healthy volunteers showed that an increase in the geomagnetic activity led to an increase in tissue perfusion, variability of blood flow and growth of the amplitude of neurogenic and myogenic oscillations in four volunteers. It was found that the degree of microcirculation sensitivity to the level of geomagnetic activity values with time and is proportional to its average level in the period of measurement. A comparison of frequency ranges of oscillations of blood flow and variations of the geomagnetic activity shows that neurogenic and myogenic oscillations showing the highest sensitivity to the geomagnetic activity have the same frequency as geomagnetic Pc3 pulsations. The pulsations of this frequency range are excited mainly during geomagnetic disturbances, which may explain the correlation between the microcirculation parameters and the Kp index. The relation of the amplitude-frequency characteristics of Pc3-pulsations can explain the results obtained using the alternating magnetic fields. PMID:20968090

  19. Globally strong geomagnetic field intensity circa 3000 years ago

    NASA Astrophysics Data System (ADS)

    Hong, Hoabin; Yu, Yongjae; Lee, Chan Hee; Kim, Ran Hee; Park, Jingyu; Doh, Seong-Jae; Kim, Wonnyon; Sung, Hyongmi

    2013-12-01

    High-fidelity geomagnetic field intensity determination was carried out using 191 baked fragments collected from 20 kilns or hearths with ages ranging between ∼1200 BC and ∼AD 1725 in South Korea. Geomagnetic field intensity variation displayed three narrow minima at ∼800-700 BC, ∼AD 700, and ∼AD 1600 and two maxima at ∼1200-1100 BC and ∼AD 1000-1100. In most time intervals, virtual axial dipole moment (VADM) variation is confined within 20% of the present VADM. However, geomagnetic field intensity circa 3000 yr ago is nearly 40% larger than the present value. Such high VADMs circa 3000 yr ago are in phase with those in other longitudinal bands in northern hemisphere centered at 5E (France), 30E (the Middle East) and 200E (Hawaii). Although strong geomagnetic field intensity circa 3000 yr ago is globally synchronous, the highest VADM occurs at slightly different time intervals in different locations. Hence it is possible that the globally strong geomagnetic field intensity circa 3000 yr ago reflects the migration of persistent hemispheric flux in northern hemisphere or an episode of geomagnetic field hemispheric asymmetry.

  20. Geomagnetic storm environments and effects on electrical systems

    SciTech Connect

    Tesche, F.M. , Dallas, TX ); Barnes, P.R. )

    1992-01-01

    This paper briefly reviews the behavior of the earth's magnetic field during a geomagnetic storm. Temporal variations of the B-field on the earths surface can induce an electric field in the earth, and this E-field will induce currents to flow in long, grounded conductors. Previous experience with geomagnetic storms indicates that such geomagnetically-induced currents can cause damage to power system components, and at times, can cause power blackouts. This paper presents some recently measured geomagnetic field variations, and illustrates how the induced electric field can be calculated, assuming a simple model of the imperfectly conducting earth. This calculation may be performed either in the time or in the frequency domain. Approximations to the time dependence of the geomagnetic field permit an analytical evaluation of the corresponding E-field in the earth, and this results in a simple expression for the transient Enfield. A knowledge of this Enfield is important in understanding the effects of geomagnetic storms on the power system, and in devising protection methods.

  1. Are migrating raptors guided by a geomagnetic compass?

    USGS Publications Warehouse

    Thorup, Kasper; Fuller, Mark R.; Alerstam, T.; Hake, M.; Kjellen, N.; Standberg, R.

    2006-01-01

    We tested whether routes of raptors migrating over areas with homogeneous topography follow constant geomagnetic courses more or less closely than constant geographical courses. We analysed the routes taken over land of 45 individual raptors tracked by satellite-based radiotelemetry: 25 peregrine falcons, Falco peregrinus, on autumn migration between North and South America, and seven honey buzzards, Pernis apivorus, and 13 ospreys, Pandion haliaetus, on autumn migration between Europe and Africa. Overall, migration directions showed a better agreement with constant geographical than constant geomagnetic courses. Tracks deviated significantly from constant geomagnetic courses, but were not significantly different from geographical courses. After we removed movements directed far from the mean direction, which may not be migratory movements, migration directions still showed a better agreement with constant geographical than constant geomagnetic courses, but the directions of honey buzzards and ospreys were not significantly different from constant geomagnetic courses either. That migration routes of raptors followed by satellite telemetry are in closer accordance with constant geographical compass courses than with constant geomagnetic compass courses may indicate that geographical (e.g. based on celestial cues) rather than magnetic compass mechanisms are of dominating importance for the birds' long-distance orientation.

  2. Local geomagnetic indices and their role in space weather

    NASA Astrophysics Data System (ADS)

    Guerrero, Antonio; Cid, Consuelo; Saiz, Elena; Palacios, Judith; Cerrato, Yolanda

    2016-04-01

    The analysis of local geomagnetic disturbances (specific longitude and latitude) have recently proved to play an important role in space weather research. Localized strong (high intensity) and impulsive (fast developed and fast recovered) geomagnetic disturbances are typically recorded at high latitudes and commonly related to field-aligned currents. These type of disturbances are also recorded, less frequently, at mid and low latitudes, representing an important hazard for technology. In order to obtain geomagnetic disturbances (geomagnetic index) from the records at a certain observatory, a baseline has to be removed. The baseline is usually determined taking into account geomagnetic secular variation and solar quiet time. At mid-latitudes the shape of the daily solar quiet component presents a strong day-to-day variability difficult to predict. In this work we present a new technique capable to determine the baseline at mid-latitudes which allows us to obtain a high resolution local geomagnetic index with the highest accuracy ever obtained at mid-latitudes.

  3. Causes of the Sep. 12-13, 2014 geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Cho, Kyung-Suk; Kim, Rooksoon; Park, Sung-Hong; Kim, Sujin

    2015-08-01

    Solar cycle 24 is very modest compared to previous solar cycles. The solar maximum phase may have been reached in the middle of 2014 and the sunspot number has decreased since the beginning of 2015. During this period, it has been reported that only few events produced strong X-class flares, solar proton events, and geomagnetic storms. In this study we have investigated causes of the multiple geomagnetic storms occurred on September 12-13, 2014. The geomagnetic storm forecast model based on the CME observations was used for identification of the causes of the geomagnetic storms. Details of the solar source region were investigated to give an answer why the geomagnetic storms were not so strong even though they were related to fast coronal mass ejections with large earth-ward direction. As a result, we found that the first weak storm was driven by the CME related to M4.6 flare and the second minor storm was driven by one of the fast CMEs related to strong X1.6 flare. Our result shows that the reason why the second storm was not strong is that it was caused by the CME with northward magnetic field. Therefore we suggest that one of the essential ingredients for geomagnetic storm forecasting is to find out the magnetic field direction of earth-ward CMEs, which can be accomplished by investigating magnetic fields of their solar source regions a few days before their arrival to the earth.

  4. A Quaternary Geomagnetic Instability Time Scale

    NASA Astrophysics Data System (ADS)

    Singer, B. S.

    2013-12-01

    Reversals and excursions of Earth's geomagnetic field create marker horizons that are readily detected in sedimentary and volcanic rocks worldwide. An accurate and precise chronology of these geomagnetic field instabilities is fundamental to understanding several aspects of Quaternary climate, dynamo processes, and surface processes. For example, stratigraphic correlation between marine sediment and polar ice records of climate change across the cryospheres benefits from a highly resolved record of reversals and excursions. The temporal patterns of dynamo behavior may reflect physical interactions between the molten outer core and the solid inner core or lowermost mantle. These interactions may control reversal frequency and shape the weak magnetic fields that arise during successive dynamo instabilities. Moreover, weakening of the axial dipole during reversals and excursions enhances the production of cosmogenic isotopes that are used in sediment and ice core stratigraphy and surface exposure dating. The Geomagnetic Instability Time Scale (GITS) is based on the direct dating of transitional polarity states recorded by lava flows using the 40Ar/39Ar method, in parallel with astrochronologic age models of marine sediments in which O isotope and magnetic records have been obtained. A review of data from Quaternary lava flows and sediments yields a GITS comprising 10 polarity reversals and 27 excursions during the past 2.6 million years. Nine of the ten reversals bounding chrons and subchrons are associated with 40Ar/39Ar ages of transitionally-magnetized lava flows. The tenth, the Guass-Matuyama chron boundary, is tightly bracketed by 40Ar/39Ar dated ash deposits. Of the 27 well-documented excursions, 14 occurred during the Matuyama chron and 13 during the Brunhes chron; 19 have been dated directly using the 40Ar/39Ar method on transitionally-magnetized volcanic rocks and form the backbone of the GITS. Excursions are clearly not the rare phenomena once thought

  5. Comparison between the effect of two geomagnetic storms with the same seasonal and daily characteristics and different intensity on the European ionosphere.

    NASA Astrophysics Data System (ADS)

    Rodriguez-Bouza, Marta; Herraiz, Miguel; Rodríguez-Caderot, Gracía; Paparini, Claudia; Otero, Xurxo; Radicella, Sandro M.

    2016-04-01

    This work presents an analysis of the ionospheric disturbance caused by two geomagnetic storms occurred on the same day, 17th March, but one in 2013 and other in 2015. The greatest intensity of both storms occurs after sunset when geomagnetic indexes (Dst index, Kp and Ap) reached the peak values. Both geomagnetic storms can be classified as intense according to the Dst index criteria. The storm of March 17, 2015, ("St Patricḱs storm"), can be considered even "severe" because the Dst index dropped off -200nT. The solar origins of both geomagnetic storms were magnetic filament eruptions followed by Coronal Mass Ejections, CME. The ionospheric behavior has been studied through the total electron content, TEC. This parameter is obtained from RINEX files processed using the calibration technique developed by Prof. Luigi Ciraolo. RINEX files from selected GNSS stations on Europe belonging to International GPS Service, IGS, and EUREF Permanent Network, have been used. The calibration technique assumes the ionospheric thin shell model to obtain vertical total electron content (vTEC) from slant total electron content (sTEC) at the Ionospheric Pierce Point. The data were obtained in periods of the geomagnetic storms and during quite days surrounding the storms days, at 1 minute sampling. The behavior of the ionosphere during the two geomagnetic storms was similar. In both cases, a positive ionospheric storm, defined as an increase on the TEC, occurred during the main phase of the geomagnetic storms on 17th of March. These increases were followed by a negative ionospheric storm, a decreasing of TEC, in the recuperation phase. However, in the event of 2015, the positive ionospheric storm of the main phase had more intensity but the same duration than that of 2013 and for the negative ionospheric storm both, intensity and duration, were largest in 2015 than in 2013.

  6. Long-term prediction of solar and geomagnetic activity daily time series using singular spectrum analysis and fuzzy descriptor models

    NASA Astrophysics Data System (ADS)

    Mirmomeni, M.; Kamaliha, E.; Shafiee, M.; Lucas, C.

    2009-09-01

    Of the various conditions that affect space weather, Sun-driven phenomena are the most dominant. Cyclic solar activity has a significant effect on the Earth, its climate, satellites, and space missions. In recent years, space weather hazards have become a major area of investigation, especially due to the advent of satellite technology. As such, the design of reliable alerting and warning systems is of utmost importance, and international collaboration is needed to develop accurate short-term and long-term prediction methodologies. Several methods have been proposed and implemented for the prediction of solar and geomagnetic activity indices, but problems in predicting the exact time and magnitude of such catastrophic events still remain. There are, however, descriptor systems that describe a wider class of systems, including physical models and non-dynamic constraints. It is well known that the descriptor system is much tighter than the state-space expression for representing real independent parametric perturbations. In addition, the fuzzy descriptor models as a generalization of the locally linear neurofuzzy models are general forms that can be trained by constructive intuitive learning algorithms. Here, we propose a combined model based on fuzzy descriptor models and singular spectrum analysis (SSA) (FD/SSA) to forecast a number of geomagnetic activity indices in a manner that optimizes a fuzzy descriptor model for each of the principal components obtained from singular spectrum analysis and recombines the predicted values so as to transform the geomagnetic activity time series into natural chaotic phenomena. The method has been applied to predict two solar and geomagnetic activity indices: geomagnetic aa and solar wind speed (SWS) of the solar wind index. The results demonstrate the higher power of the proposed method-- compared to other methods -- for predicting solar activity.

  7. Geomagnetic variations possibly associated with the Pisco earthquake on 15 August 2007, Peru

    NASA Astrophysics Data System (ADS)

    Takla, E. M.; Yumoto, K.; Ishitsuka, J.; Rosales, D.; Dutra, S.; Uozumi, T.; Abe, S.

    2012-02-01

    On 15 August 2007, Pisco earthquake (magnitude 8.0) hit the central coast of Peru near the MAGDAS Ancon (ANC) station. Geomagnetic data from ANC and other reference stations have been analyzed to detect any signature related to this great earthquake. Results indicate the presence of annual geomagnetic variations in the vertical component at ANC and Huancayo (HUA) stations (in the vicinity of the epicenter of Pisco earthquake). These variations have a quasi-sinusoidal waveform with amplitudes of about 10 and 5 nT for ANC and HUA stations respectively. They appeared clearly during the period preceding the onset of the Pisco earthquake especially at ANC station. By using HUA, Eusebio (EUS) and Kourou (KOU) as reference stations in the vicinity and away from the epicenter of Pisco earthquake, a clear disappearance of the diurnal variation of the vertical component was observed at ANC station during the day of earthquake. Moreover, the Pisco earthquake and another earthquake (on 29 March 2008) near ANC station were found to occur concurrently with the depressions in the polarization ratio (Z/H) of Pc 3 (10-45 s) amplitude. Such anomalous variations appear to be a result of changes in the crustal stress field and the lithospheric conductivity in the studied region.

  8. Observed geomagnetic induction effect on Dst-related magnetic observations under different disturbance intensities of the magnetospheric ring current

    NASA Astrophysics Data System (ADS)

    Xu, Dan; Chen, Huaran; Gao, Mengtan

    2015-01-01

    Based on the spherical harmonic expansion of geomagnetic disturbance observed on the mid-latitude surface of the Earth, external and internal field separation is conducted in which the external component is magnetic disturbance caused by the magnetospheric ring current and the internal component is that raised by the correspondingly induced currents within the Earth. The objectives are to evaluate the influences of the induced internal field on the surface magnetic observations and to reveal the response performance of internal geomagnetic induction under different strengths of magnetospheric ring current fluctuations for better understanding of the disturbance storm time ( Dst) index variations. The results show that the ratio of the internal component to surface observation does not remain constant in storm time. During the main phase of the storm, the ratio variation follows the pattern of logarithmic growth with storm evolution up to the top value at the Dst-minimum; then, the ratio slowly decreases in the long recovery phase. Multiple small logarithmic growths are superimposed on the traces of internal ratios, corresponding to temporary ring current intensification during the storm main phase and amplifying the effect of this intensification on surface magnetic observations. With the intensification of magnetospheric storms from the level of (-200 nT, - 100 nT) to (-300 nT, - 200 nT) and (-500 nT, - 300 nT) classified with the Dst-minimum, the top value of the ratio averaged for each storm group in the superposed epoch analysis method increases from the value of 0.295 ± 0.014 to 0.300 ± 0.016 and 0.308 ± 0.015, respectively. It is demonstrated that the geomagnetic induction exceeds the linear relation with the intensification of the external field, which is physically reasonable and coincident with the Faraday's law of induction. Due to the effects of high induction of the oceans and lateral heterogeneity of electric conductivity distribution in the upper

  9. Intensity and Variability of Geomagnetic Time Derivatives

    NASA Astrophysics Data System (ADS)

    Jackel, B. J.; Connors, M. G.; Reiter, K.; Singleton, M.

    2015-12-01

    Time derivatives of the geomagnetic field are studied for more than a decade of observations at more than a dozen sites in northern Canada. In the auroral zone the derivative magnitude observed by 5-second fluxgate magnetometers often has a lognormal distribution. Parameter estimates corresponding to intensity (log-mean) and variability (log-variance) are nearly independent and have very different statistical properties. Variability is essentially a random variable, while intensity autocorrelation times are on the order of tens of minutes. Observed intensities are highly correlated with AE, and increase with solar wind speed and the magnitude of Bz<0. Both variability and intensity have local-time maxima before and after midnight, but with different patterns that combine to produce a larger post-midnight peak. Post-midnight variability is almost completely determined by latitude, with largest values at subauroral sites and smallest values in the polar cap. Intensity depends on latitude, but also has a site-specific element which may be due to local conductivity.

  10. The Livingston Island Geomagnetic and Ionospheric Observatory

    NASA Astrophysics Data System (ADS)

    Altadill, David; Marsal, Santiago; Blanch, Estefania; Miquel Torta, J.; Quintana-Seguí, Pere; Germán Solé, J.; Cid, Òscar; José Curto, Juan; Ibáñez, Miguel; Segarra, Antoni; Lluís Pijoan, Joan; Juan, Juan Miguel

    2014-05-01

    The Ebre Observatory Institute manages a geophysical observatory installed at the Spanish Antarctic Station (SAS) Juan Carlos I. It was set up in 1995 and it has been updated yearly by our team throughout several projects carried out since then. Nowadays, it hosts a magnetic station providing 1-second data of the 3 components (X, Y, Z) and the total force (F) during the entire year, and an ionospheric station providing vertical and oblique data during austral summer. This observatory has provided long data series of high scientific value from this remote region of the Earth. They have been used to improve the knowledge of the climate and weather behavior of the geomagnetic field and ionosphere in the area, and to model and expand the capacity of data transmission. This contribution aims to present a brief review of the instruments installed at SAS, the research results obtained from their data, and the developing activities under the current project. Finally, future perspectives are outlined with regard to adapting our geophysical observatory to the evolving needs of observatory practice.

  11. Geomagnetism during solar cycle 23: Characteristics.

    PubMed

    Zerbo, Jean-Louis; Amory-Mazaudier, Christine; Ouattara, Frédéric

    2013-05-01

    On the basis of more than 48 years of morphological analysis of yearly and monthly values of the sunspot number, the aa index, the solar wind speed and interplanetary magnetic field, we point out the particularities of geomagnetic activity during the period 1996-2009. We especially investigate the last cycle 23 and the long minimum which followed it. During this period, the lowest values of the yearly averaged IMF (3 nT) and yearly averaged solar wind speed (364 km/s) are recorded in 1996, and 2009 respectively. The year 2003 shows itself particular by recording the highest value of the averaged solar wind (568 km/s), associated to the highest value of the yearly averaged aa index (37 nT). We also find that observations during the year 2003 seem to be related to several coronal holes which are known to generate high-speed wind stream. From the long time (more than one century) study of solar variability, the present period is similar to the beginning of twentieth century. We especially present the morphological features of solar cycle 23 which is followed by a deep solar minimum. PMID:25685427

  12. Geomagnetism during solar cycle 23: Characteristics

    PubMed Central

    Zerbo, Jean-Louis; Amory-Mazaudier, Christine; Ouattara, Frédéric

    2012-01-01

    On the basis of more than 48 years of morphological analysis of yearly and monthly values of the sunspot number, the aa index, the solar wind speed and interplanetary magnetic field, we point out the particularities of geomagnetic activity during the period 1996–2009. We especially investigate the last cycle 23 and the long minimum which followed it. During this period, the lowest values of the yearly averaged IMF (3 nT) and yearly averaged solar wind speed (364 km/s) are recorded in 1996, and 2009 respectively. The year 2003 shows itself particular by recording the highest value of the averaged solar wind (568 km/s), associated to the highest value of the yearly averaged aa index (37 nT). We also find that observations during the year 2003 seem to be related to several coronal holes which are known to generate high-speed wind stream. From the long time (more than one century) study of solar variability, the present period is similar to the beginning of twentieth century. We especially present the morphological features of solar cycle 23 which is followed by a deep solar minimum. PMID:25685427

  13. Periodic substorm activity in the geomagnetic tail

    NASA Technical Reports Server (NTRS)

    Huang, C. Y.; Eastman, T. E.; Frank, L. A.; Williams, D. J.

    1983-01-01

    On 19 May 1978 an anusual series of events is observed with the Quadrispherical LEPEDEA on board the ISEE-1 satellite in the Earth's geomagnetic tail. For 13 hours periodic bursts of both ions and electrons are seen in all the particle detectors on the spacecraft. On this day periodic activity is also seen on the ground, where multiple intensifications of the electrojets are observed. At the same time the latitudinal component of the interplanetary magnetic field shows a number of strong southward deflections. It is concluded that an extended period of substorm activity is occurring, which causes repeated thinnings and recoveries of the plasma sheet. These are detected by ISEE, which is situated in the plasma sheet boundary layer, as periodic dropouts and reappearances of the plasma. Comparisons of the observations at ISEE with those at IMP-8, which for a time is engulfed by the plasma sheet, indicate that the activity is relatively localized in spatial extent. For this series of events it is clear that a global approach to magnetospheric dynamics, e.g., reconnection, is inappropriate.

  14. Equatorial airglow and the ionospheric geomagnetic anomaly.

    NASA Technical Reports Server (NTRS)

    Chandra, S.; Reed, E. I.; Troy, B. E., Jr.; Blamont, J. E.

    1973-01-01

    Ogo 4 observations of the O I (6300-A) emissions have revealed a global pattern hitherto undetected from the ground-based observations. It is seen that the postsunset emission of O I (6300 A) in October 1967 is very asymmetrical with respect to the geomagnetic equator in certain longitude regions and shows poor correlation with the electron density measured simultaneously from the same spacecraft. This asymmetry is less marked in the UV airglow, O I (1356 A), which appears to vary as the square of the maximum electron density in the F region. The horizon scan data of the 6300-A airglow reveal that the latitudinal asymmetry is associated with asymmetry in the height of the O I (6300-A) emission and hence with the altitude of the F2 peak. From the correlative studies of the airglow and the ionospheric measurements the mechanisms of the UV and the 6300 A emissions are discussed in terms of the processes involving radiative and dissociative recombination. Theoretical expressions are developed which relate the airglow data to the ionospheric parameters.

  15. Geomagnetic main field modeling with DMSP

    NASA Astrophysics Data System (ADS)

    Alken, P.; Maus, S.; Lühr, H.; Redmon, R. J.; Rich, F.; Bowman, B.; O'Malley, S. M.

    2014-05-01

    The Defense Meteorological Satellite Program (DMSP) launches and maintains a network of satellites to monitor the meteorological, oceanographic, and solar-terrestrial physics environments. In the past decade, geomagnetic field modelers have focused much attention on magnetic measurements from missions such as CHAMP, Ørsted, and SAC-C. With the completion of the CHAMP mission in 2010, there has been a multiyear gap in satellite-based vector magnetic field measurements available for main field modeling. In this study, we calibrate the special sensor magnetometer instrument on board DMSP to create a data set suitable for main field modeling. These vector field measurements are calibrated to compute instrument timing shifts, scale factors, offsets, and nonorthogonality angles of the fluxgate magnetometer cores. Euler angles are then computed to determine the orientation of the vector magnetometer with respect to a local coordinate system. We fit a degree 15 main field model to the data set and compare with the World Magnetic Model and Ørsted scalar measurements. We call this model DMSP-MAG-1, and its coefficients and software are available for download at http://geomag.org/models/dmsp.html. Our results indicate that the DMSP data set will be a valuable source for main field modeling for the years between CHAMP and the recently launched Swarm mission.

  16. INTERNATIONAL STUDY ON 'ARTEMIA'. XXVI. FOOD VALUE OF NAUPLII FROM REFERENCE 'ARTEMIA' CYSTS AND FOUR GEOGRAPHICAL COLLECTIONS OF 'ARTEMIA' FOR MUD CRAB LARVAE

    EPA Science Inventory

    Nauplii from 4 commercially available geographical collections of Artemia and nauplii hatched from the Reference Artemia Cysts were compared for their effects on survival and growth of Rhithropanopeus harrisii larvae. In addition, nauplii from these sources were analyzed for thei...

  17. History of the Munich-Maisach-Fürstenfeldbruck Geomagnetic Observatory

    NASA Astrophysics Data System (ADS)

    Soffel, H. C.

    2015-07-01

    The Munich-Maisach-Fürstenfeldbruck Geomagnetic Observatory is one of the observatories with the longest recordings of the geomagnetic field. It started with hourly measurements on 1 August 1840. The founder of the observatory in Munich was Johann von Lamont (1805-1879), the Director of the Royal Bavarian Astronomical Observatory. He had been stimulated to build his own observatory by the initiative of the Göttingen Magnetic Union founded in 1834 by Alexander von Humboldt (1769-1859) and Carl Friedrich Gauss (1777-1855). Before 1840 fewer than five observatories existed; the most prominent ones were those in London and Paris. At the beginning Lamont used equipment delivered by Gauss in Göttingen, but soon started to build instruments of his own design. Among them was a nonmagnetic theodolite which allowed precise geomagnetic measurements to be made also in the field. During the 1850s Lamont carried out geomagnetic surveys and produced geomagnetic maps for Germany and many other European countries. At the end of the nineteenth century accurate geomagnetic measurements in Munich became more and more disturbed by the magnetic stray fields from electric tramways and industry. During this period the quality of the data suffered and the measurements had to be interrupted several times. After a provisional solution in Maisach, a village 25 km west of Munich, a final solution could be found in the vicinity of the nearby city of Fürstenfeldbruck. Here the measurements started again on 1 January 1939. Since the 1980s the observatory has been part of INTERMAGNET, an organization providing almost real-time geomagnetic data of the highest quality.

  18. Trends of solar-geomagnetic activity, cosmic rays, atmosphere, and climate changes

    NASA Astrophysics Data System (ADS)

    Voronin, N.; Avakyan, S.

    2009-04-01

    The results are presented of the analysis of trends in the solar-geomagnetic activity and intensity of galactic cosmic rays (GCR) for the several eleven-year solar cycles. The indication has been revealed of the change of signs in the long-term changes in geomagnetic activity (aa-index) and the GCR in recent years. These changes correspond to the changes of sings in long-term trends in some of atmospheric parameters (transparency, albedo, cloudness, the content of water vapour, methane, ozone, the erythemal radiation flux). These global changes in atmosphere is most important problem of the up-to-date science. The global warming observed during the several past decades presents a real danger for the mankind. Till present the predominant point of view has been that the main cause of the increase of mean surface air temperature is the increase of concentrations of the anthropogenic gases first of all carbon dioxide CO2 and methane CH_4. Indeed, from the beginning of nineteen century the concentration of CO2 in the atmosphere has been growing and now it exceeds the initial level by the factor of 1.4 and the speed of this increase being growing too. This was the reason of international efforts to accept the Kyoto Protocol which limited the ejections of greenhouse gases. However there are premises which show that the influence of solar variability on the climate should be taken into account in the first place. The obtained results are analyzed from the point of view of well known effects of GCR influence on weather and climate with taken into account also a novel trigger mechanism in solar-terrestrial relations what allows revaluation of the role of solar flares and geomagnetic storms. The mechanism explains how agents of solar and geomagnetic activities affect atmospheric processes. This first agent under consideration is variation of fluxes of solar EUV and X-ray radiation. The second agent is fluxes of electrons and protons which precipitate from radiation belts as a

  19. Ready Reference.

    ERIC Educational Resources Information Center

    Bowker Annual Library and Book Trade Almanac, 1994

    1994-01-01

    Three articles provide publishers' and distributors' telephone numbers; information on how to obtain an ISBN (International Standard Book Number); and information on how to obtain an ISSN (International Standard Serial Number). (LRW)

  20. Geomagnetism and climate I: the last 400 years

    NASA Astrophysics Data System (ADS)

    Nevanlinna, H.; Shumilov, O.; Mörner, N.-A.; Dergachev, V.

    2003-04-01

    During the last 400 years there seems to exist a close linkage between sunspot activity and paleoclimate. The combined Schwabe Gleisberg cycles provide a good approximation of past climate. Changes in the phase of the sunspot cycles exhibit a very close correlation with observed changes in climate for the last 150 years. The heliomagnetic aa-index provides a close correlation with climate over the last 150 years. The close correlation between sunspot activity and atmospheric changes in radiocarbon indicates that changes in heliomagnetic interaction with the Earth’s magnetosphere play a central role in this solar-terrestrial interaction; via its modulation of the cosmic ray flux or its modulation of Earth’s rate of rotation. Variations in cosmic ray flux have the capacity of affecting Earth’s climate via its modulation of airglow and cloudiness (especially at the level around 15 km). There is a good correlation between Solar Wind intensity and Earth’s rate of rotation (LOD), implying that variations in Solar Wind intensity (sunspot activity) act in retarding and speeding up in the spin rate of Planet Earth. During the Spörer, Maunder and Dalton Sunspot Minima, the Earth’s rate of rotation was significantly speeded-up, affecting the ocean surface circulation and the atmospheric circulation as to create significant changes in local climate; “Little Ice Ages” in western and northern Europe and “Little Interglacial” in southwest Europe and northwest Africa. In conclusion, Earth’s climate seems closely driven by changes in sunspot activity. This correlation may operate via the cosmic ray effects on airglow and/or cloudiness, or via the heliomagnetic (Solar Wind) effects on Earth’s rate of rotation, or a combination of these processes. Changes in the Earth’s own internal geomagnetic field seem to have played little or no role during this time period. Nor are there any reasons to advocate major changes in Solar irradiance.

  1. Characterization of the International Humic Substances Society standard and reference fulvic and humic acids by solution state carbon-13 (13C) and hydrogen-1 (1H) nuclear magnetic resonance spectrometry

    USGS Publications Warehouse

    Thorn, Kevin A.; Folan, Daniel W.; MacCarthy, Patrick

    1989-01-01

    Standard and reference samples of the International Humic Substances Society have been characterized by solution state carbon-13 and hydrogen-1 nuclear magnetic resonance (NMR) spectrometry. Samples included the Suwannee River, soil, and peat standard fulvic and humic acids, the Leonardite standard humic acid, the Nordic aquatic reference fulvic and humic acids, and the Summit Hill soil reference humic acid. Aqueous-solution carbon-13 NMR analyses included the measurement of spin-lattice relaxation times, measurement of nuclear Overhauser enhancement factors, measurement of quantitative carbon distributions, recording of attached proton test spectra, and recording of spectra under nonquantitative conditions. Distortionless enhancement by polarization transfer carbon-13 NMR spectra also were recorded on the Suwannee River fulvic acid in deuterated dimethyl sulfoxide. Hydrogen-1 NMR spectra were recorded on sodium salts of the samples in deuterium oxide. The carbon aromaticities of the samples ranged from 0.24 for the Suwannee River fulvic acid to 0.58 for the Leonardite humic acid.

  2. High latitude TEC fluctuations and irregularity oval during geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Shagimuratov, I. I.; Krankowski, A.; Ephishov, I.; Cherniak, Yu.; Wielgosz, P.; Zakharenkova, I.

    2012-06-01

    GPS measurements obtained by the global IGS network were used to study the occurrence of TEC fluctuations in the northern and southern high-latitude ionosphere during severe geomagnetic storms. In the northern hemisphere, GPS stations located higher than 55N Corrected Geomagnetic Latitude (CGL) at different longitudes were selected. In the southern hemisphere, Antarctic permanent GPS stations were used. Dual-frequency GPS measurements for individual satellite passes served as raw data. As a measure of fluctuation activity the rate of TEC (ROT) was used, and the fluctuation intensity was evaluated using the ROTI index. Using daily GPS measurements from all selected stations, images of the spatial and temporal behavior of TEC fluctuations were formed (in Corrected Geomagnetic Coordinates—CGC and geomagnetic local time—GLT). Similarly to the auroral oval, these images demonstrate an irregularity oval. The occurrence of the irregularity oval relates to the auroral oval, cusp and polar cap. During a storm, the intensity of TEC fluctuations essentially increased. The irregularity oval expands equatorward with an increase of magnetic activity. The study showed that the existing high-latitude GPS stations can provide a permanent monitoring tool for the irregularity oval in near real-time. In this paper, the features of the development of phase fluctuations at the geomagnetic conjugate points, and inter-hemispheric differences and similarities during winter and summer conditions, are discussed.

  3. Relativistic Electron Acceleration and Loss During Small Geomagnetic Storms

    NASA Astrophysics Data System (ADS)

    Anderson, B.; Millan, R. M.; Reeves, G. D.; Friedel, R. H. W.

    2014-12-01

    Relativistic electron precipitation events were detected by early BARREL (Balloon Array for Radiation-belt Relativistic Electron Losses) payloads during small geomagnetic storms (minimum DST greater than -50nT), coincident with significant enhancement of relativistic electron fluxes at geosynchronous as measured by GOES. Such small geomagnetic storms have not been studied as in depth as larger storms, even though they are capable of pumping-up or depleting the radiation belts equally as extremely as their larger counterparts, this study finds. Since much of the past few years has been quiet, it is necessary to extend previous studies to include smaller storms. We perform a statistical analysis of relativistic electron flux response at geosynchronous to small geomagnetic storms over an 11 year period (1989-2000) using LANL satellite data, similar to previous studies of larger geomagnetic storms. We investigate changes in relativistic electron flux response with various solar wind parameters, as well as extend the statistical analysis of small and large geomagnetic storms with data sets now available from the Van Allen Probes.

  4. Low Latitude Pulsations Associated with Different Phases of Geomagnetic Storms

    NASA Astrophysics Data System (ADS)

    Bulusu, J.; Vankayala, R. C.; Sinha, A. K.; Vichare, G.; Thomas, N.

    2014-12-01

    During geomagnetic storm lot of free energy is available in the magnetosphere and this energy can act as feeder to electromagnetic waves in different frequency bands. A classical geomagnetic storm consists mainly of four phases i.e. SSC (Sudden Storm commencement), initial Phase, main phase and recovery phase. In this paper, we investigate the characteristics of electromagnetic waves in ULF (ultra low frequency) band associated with different phases of geomagnetic storms. Electromagnetic waves in ULF band (Period~ 10-100s) in the Earth's magnetosphere are generally termed as geomagnetic pulsations. A detailed statistical analysis has been performed over ten years of geomagnetic data from low latitude ground stations in Indian and Japanese sectors. The study reveals that storms in general, are accompanied with continuous pulsations of different frequency bands during different phases. In particular, the main phase of 91 % of intense storms was accompanied with pulsations in Pc5 band (frequency~ 2-7 mHz). However, the occurrence of these pulsations was less frequent during main phase of weak to moderate storms. Further, the amplitude of these pulsations increased with the intensity of storm.

  5. Geomagnetic activity and polar surface air temperature variability

    NASA Astrophysics Data System (ADS)

    Seppälä, A.; Randall, C. E.; Clilverd, M. A.; Rozanov, E.; Rodger, C. J.

    2009-10-01

    Here we use the ERA-40 and ECMWF operational surface level air temperature data sets from 1957 to 2006 to examine polar temperature variations during years with different levels of geomagnetic activity, as defined by the A p index. Previous modeling work has suggested that NO x produced at high latitudes by energetic particle precipitation can eventually lead to detectable changes in surface air temperatures (SATs). We find that during winter months, polar SATs in years with high A p index are different than in years with low A p index; the differences are statistically significant at the 2-sigma level and range up to about ±4.5 K, depending on location. The temperature differences are larger when years with wintertime Sudden Stratospheric Warmings (SSWs) are excluded. We take into account solar irradiance variations, unlike previous analyses of geomagnetic effects in ERA-40 and operational data. Although we cannot conclusively show that the polar SAT patterns are physically linked by geomagnetic activity, we conclude that geomagnetic activity likely plays a role in modulating wintertime surface air temperatures. We tested our SAT results against variation in the Quasi Biennial Oscillation, the El Niño Southern Oscillation and the Southern Annular Mode. The results suggested that these were not driving the observed polar SAT variability. However, significant uncertainty is introduced by the Northern Annular Mode, and we cannot robustly exclude a chance linkage between sea surface temperature variability and geomagnetic activity.

  6. Improving geomagnetic observatory data in the South Atlantic Anomaly

    NASA Astrophysics Data System (ADS)

    Matzka, Jürgen; Morschhauser, Achim; Brando Soares, Gabriel; Pinheiro, Katia

    2016-04-01

    The Swarm mission clearly proofs the benefit of coordinated geomagnetic measurements from a well-tailored constellation in order to recover as good as possible the contributions of the various geomagnetic field sources. A similar truth applies to geomagnetic observatories. Their scientific value can be maximised by properly arranging the position of individual observatories with respect to the geometry of the external current systems in the ionosphere and magnetosphere, with respect to regions of particular interest for secular variation, and with respect to regions of anomalous electric conductivity in the ground. Here, we report on our plans and recent efforts to upgrade geomagnetic observatories and to recover unpublished data from geomagnetic observatories at low latitudes in the South Atlantic Anomaly. In particular, we target the magnetic equator with the equatorial electrojet and low latitudes to characterise the Sq- and ring current. The observatory network that we present allows also to study the longitudinal structure of these external current systems. The South Atlantic Anomaly region is very interesting due to its secular variation. We will show newly recovered data and comparisons with existing data sets. On the technical side, we introduce low-power data loggers. In addition, we use mobile phone data transfer, which is rapidly evolving in the region and allows timely data access and quality control at remote sites that previously were not connected to the internet.

  7. Airport geomagnetic surveys in the United States

    USGS Publications Warehouse

    Berarducci, A.

    2006-01-01

    The Federal Aviation Administration (FAA) and the United States military have requirements for design, location, and construction of compass calibration pads (compass roses), these having been developed through collaboration with US Geological Survey (USGS) personnel. These requirements are detailed in the FAA Advisory Circular AC 150/5300-13, Appendix 4, and in various military documents, such as Handbook 1021/1, but the major requirement is that the range of declination measured within 75 meters of the center of a compass rose be less than or equal to 30 minutes of arc. The USGS Geomagnetism Group has developed specific methods for conducting a magnetic survey so that existing compass roses can be judged in terms of the needed standards and also that new sites can be evaluated for their suitability as potentially new compass roses. First, a preliminary survey is performed with a total-field magnetometer, with differences over the site area of less than 75nT being sufficient to warrant additional, more detailed surveying. Next, a number of survey points are established over the compass rose area and nearby, where declination is to be measured with an instrument capable of measuring declination to within 1 minute of arc, such as a Gurley transit magnetometer, DI Flux theodolite magnetometer, or Wild T-0. The data are corrected for diurnal and irregular effects of the magnetic field and declination is determined for each survey point, as well as declination range and average of the entire compass rose site. Altogether, a typical survey takes about four days to complete. ?? 2006 Springer.

  8. Dynamical similarity of geomagnetic field reversals.

    PubMed

    Valet, Jean-Pierre; Fournier, Alexandre; Courtillot, Vincent; Herrero-Bervera, Emilio

    2012-10-01

    No consensus has been reached so far on the properties of the geomagnetic field during reversals or on the main features that might reveal its dynamics. A main characteristic of the reversing field is a large decrease in the axial dipole and the dominant role of non-dipole components. Other features strongly depend on whether they are derived from sedimentary or volcanic records. Only thermal remanent magnetization of lava flows can capture faithful records of a rapidly varying non-dipole field, but, because of episodic volcanic activity, sequences of overlying flows yield incomplete records. Here we show that the ten most detailed volcanic records of reversals can be matched in a very satisfactory way, under the assumption of a common duration, revealing common dynamical characteristics. We infer that the reversal process has remained unchanged, with the same time constants and durations, at least since 180 million years ago. We propose that the reversing field is characterized by three successive phases: a precursory event, a 180° polarity switch and a rebound. The first and third phases reflect the emergence of the non-dipole field with large-amplitude secular variation. They are rarely both recorded at the same site owing to the rapidly changing field geometry and last for less than 2,500 years. The actual transit between the two polarities does not last longer than 1,000 years and might therefore result from mechanisms other than those governing normal secular variation. Such changes are too brief to be accurately recorded by most sediments. PMID:23038471

  9. Membrane reference electrode

    DOEpatents

    Redey, L.; Bloom, I.D.

    1988-01-21

    A reference electrode utilizes a small thin, flat membrane of a highly conductive glass placed on a small diameter insulator tube having a reference material inside in contact with an internal voltage lead. When the sensor is placed in a non-aqueous ionic electrolytic solution, the concentration difference across the glass membrane generates a low voltage signal in precise relationship to the concentration of the species to be measured, with high spatial resolution. 2 figs.

  10. Ionospheric Response to Geomagnetic Activity during 2007-2009 Solar Minimum

    NASA Astrophysics Data System (ADS)

    Chen, Yiding; Liu, Libo; Huijun Le, lake709.; Wan, Weixing

    The significant effect of weaker geomagnetic activity on ionospheric day-to-day variability during 2007-2009 solar minimum was highlighted by investigating the response of global electron content (GEC) to geomagnetic activity index Ap. A case distinctly manifests the modulation of recurrent weaker geomagnetic disturbance on GEC during the solar minimum. Statistical analyses indicate that the effect of weaker geomagnetic activity on GEC day-to-day variability is significant during 2007-2009, even under relatively quiet geomagnetic activity condition, while geomagnetic activity effect on GEC is not prominent during 2003-2005 solar cycle descending phase except under strong geomagnetic disturbance condition. Nevertheless, statistically the most important effect on GEC day-to-day variability during 2007-2009 comes from the factors other than geomagnetic activity and solar EUV irradiance.

  11. Ionospheric Response to Geomagnetic Activity during 2007-2009 Solar Minimum

    NASA Astrophysics Data System (ADS)

    Chen, Yiding; Liu, Libo; Le, Huijun; Wan, Weixing

    2014-05-01

    The significant effect of weaker geomagnetic activity on ionospheric day-to-day variability during 2007-2009 solar minimum was highlighted by investigating the response of global electron content (GEC) to geomagnetic activity index Ap. A case distinctly manifests the modulation of recurrent weaker geomagnetic disturbance on GEC during the solar minimum. Statistical analyses indicate that the effect of weaker geomagnetic activity on GEC day-to-day variability is significant during 2007-2009, even under relatively quiet geomagnetic activity condition, while geomagnetic activity effect on GEC is not prominent during 2003-2005 solar cycle descending phase except under strong geomagnetic disturbance condition. Nevertheless, statistically the most important effect on GEC day-to-day variability during 2007-2009 comes from the factors other than geomagnetic activity and solar EUV irradiance.

  12. IFCC primary reference procedures for the measurement of catalytic activity concentrations of enzymes at 37 degrees C. International Federation of Clinical Chemistry and Laboratory Medicine. Part 7. Certification of four reference materials for the determination of enzymatic activity of gamma-glutamyltransferase, lactate dehydrogenase, alanine aminotransferase and creatine kinase accord.

    PubMed

    Siekmann, Lothar; Bonora, Roberto; Burtis, Carl A; Ceriotti, Ferruccio; Clerc-Renaud, Pascale; Férard, Georges; Ferrero, Carlo A; Forest, Jean-Claude; Franck, Paul F H; Gella, F-Javier; Hoelzel, Wieland; Jørgensen, Poul Jørgen; Kanno, Takashi; Kessner, Art; Klauke, Rainer; Kristiansen, Nina; Lessinger, Jean-Marc; Linsinger, Thomas P J; Misaki, Hideo; Mueller, Mathias M; Panteghini, Mauro; Pauwels, Jean; Schiele, Françoise; Schimmel, Heinz G; Vialle, Arlette; Weidemann, Gerhard; Schumann, Gerhard

    2002-07-01

    /l (186 U/l +/- 4 U/l), for alanine aminotransferase and 1.68 microkat/l +/- 0.07 microkat/l (101 U/l +/- 4 U/l), for creatine kinase. The materials are intended for internal quality control as well as for the evaluation of test systems as required by recent European Union legislation. Furthermore, the materials can be used to transfer accuracy from a reference method to a routine procedure provided the procedures exhibit the same analytical specificity and the certified materials are commutable. PMID:12241024

  13. foF2 correlation studies with solar and geomagnetic indices for two equatorial stations

    NASA Astrophysics Data System (ADS)

    Joshua, E. O.; Nzekwe, N. M.

    2012-05-01

    The analysis of the contributions of solar and geomagnetic indices on the critical frequency of the ionospheric F2 layer (foF2)-, for different seasons and two Nigerian equatorial stations- Ibadan (Lat. 7.4°N, Long. 3.9°N) and Ilorin (Lat. 8.5°N, Long. 4.55°E)- are presented. The data set was randomly sampled across three solar cycles of periods of low, moderate and high solar activities. Solar indices used in this work are Coviten solar flux (F10.7 cm), daily solar radio flux (dF10.7), International Sunspot Number (ISSN), Smoothen Sunspot Number (SmSSN), and Sun Spot Number (SSN). The geomagnetic indices used are planetary indices Am, Aa, Ap, C9, Cp, and Kp. foF2 showed a non-linear trend with an average coefficient (R) of 0.70 across the various seasons. Regression lines for polynomials of degree n=1 to n=6 was fitted, for each data set. Am, Ap, Aa, SSN, ISSN, F10.7 cm, and dF10.7 with R values of 0.71,0.74,0.61,0.59,0.72,0.80, and 0.86, for the various geomagnetic and solar indices, had the highest contributions. We therefore advocate for SSN, ISSN, F10.7 cm, dF10.7 and Am, Ap or Aa in modeling foF2 for the African equatorial ionosphere. The results of this work are in line with the results of other works carried out at different equatorial stations.

  14. The equatorial electrojet during geomagnetic storms and substorms

    NASA Astrophysics Data System (ADS)

    Yamazaki, Yosuke; Kosch, Michael J.

    2015-03-01

    The climatology of the equatorial electrojet during periods of enhanced geomagnetic activity is examined using long-term records of ground-based magnetometers in the Indian and Peruvian regions. Equatorial electrojet perturbations due to geomagnetic storms and substorms are evaluated using the disturbance storm time (Dst) index and auroral electrojet (AE) index, respectively. The response of the equatorial electrojet to rapid changes in the AE index indicates effects of both prompt penetration electric field and disturbance dynamo electric field, consistent with previous studies based on F region equatorial vertical plasma drift measurements at Jicamarca. The average response of the equatorial electrojet to geomagnetic storms (Dst<-50 nT) reveals persistent disturbances during the recovery phase, which can last for approximately 24 h after the Dst index reaches its minimum value. This "after-storm" effect is found to depend on the magnitude of the storm, solar EUV activity, season, and longitude.

  15. Applications of dispersion relations to the geomagnetic transfer function

    NASA Astrophysics Data System (ADS)

    Marcuello, A.; Queralt, P.; Ledo, J.

    2005-05-01

    The geomagnetic transfer function is nowadays used to constrain the magnetotelluric inversion procedure given that this function contains complementary information to the impedance tensor. For the models usually employed by inversions, the real and imaginary parts of the geomagnetic transfer function are related by dispersion relations. The computation of the dispersion relations involves the Hilbert transform, and here we discuss different expressions to compute them. This computation was verified using synthetically generated geomagnetic transfer function from 2D and 3D models. The dispersion relations were applied on two cases: (a) to study the consistency between the real and imaginary parts of field recorded data, and (b) to develop a procedure to complete or extend the amount of measured data.

  16. Using the moon to probe the geomagnetic tail lobe plasma

    NASA Technical Reports Server (NTRS)

    Schubert, G.; Sonett, C. P.; Smith, B. F.; Colburn, D. S.; Schwartz, K.

    1975-01-01

    We have detected the presence of plasma in the lobes of the geomagnetic tail from observations of magnetic induction in the moon forced by time variations of the earth's magnetotail lobe field. The magnitude of the moon's tangential electromagnetic transfer function when the moon is in the lobes of the geomagnetic tail is less than that when the moon is in the solar wind or geomagnetic tail plasma sheet. The tangential transfer function when the moon is in the magnetotail lobes decreases at frequencies above about 8 mHz due to finite wavelength effects. This shows that the waves in the magnetotail lobes which drive the lunar magnetic induction must have speeds far less than the speed of light and wavelengths comparable to the size of the moon.

  17. Magnetospheric mapping with a quantitative geomagnetic field model

    NASA Technical Reports Server (NTRS)

    Fairfield, D. H.; Mead, G. D.

    1975-01-01

    Mapping the magnetosphere on a dipole geomagnetic field model by projecting field and particle observations onto the model is described. High-latitude field lines are traced between the earth's surface and their intersection with either the equatorial plane or a cross section of the geomagnetic tail, and data from low-altitude orbiting satellites are projected along field lines to the outer magnetosphere. This procedure is analyzed, and the resultant mappings are illustrated. Extension of field lines into the geomagnetic tail and low-altitude determination of the polar cap and cusp are presented. It is noted that while there is good agreement among the various data, more particle measurements are necessary to clear up statistical uncertainties and to facilitate comparison of statistical models.

  18. Geomagnetic observations on tristan da cunha, south atlantic ocean

    USGS Publications Warehouse

    Matzka, J.; Olsen, N.; Maule, C.F.; Pedersen, L.W.; Berarducci, A.M.; Macmillan, S.

    2009-01-01

    Few geomagnetic ground observations exist of the Earth's strongest core field anomaly, the South Atlantic Anomaly (SAA). The geomagnetic repeat station on the island Tristan da Cunha, located half-way between South Africa and South America at 37?? 05' S, 12?? 18' W, is therefore of crucial importance. We have conducted several sets of repeat station measurements during magnetically quiet conditions (Kp 2o or less) in 2004. The procedures are described and the results are compared to those from earlier campaigns and to the predictions of various global field models. Features of the local crustal bias field and the solar quiet daily variation are discussed. We also evaluate the benefit of continuous magnetic field recordings from Tristan da Cunha, and argue that such a data set is a very valuable addition to geomagnetic satellite data. Recently, funds were set up to establish and operate a magnetometer station on Tristan da Cunha during the Swarm magnetic satellite mission (2011-2014).

  19. The geomagnetic elements in Denmark 1928-1980

    NASA Astrophysics Data System (ADS)

    Hansen, H. A.

    Geomagnetic surveys in Denmark from 1928 till 1980 are reported. The Danish Meteorological Institute initiated a new, geomagnetic survey of Denmark in 1928 by the establishment of 10 repeat statins for observation of the geomagnetic, secular variation. The stations were visited again in 1930 and since then every fifth year. The general survey was started in 1939 and continued during the years 1946 to 1957 with the mapping of Northern Jutland. In 1967 the survey taken with a coarser spacing of the measured points during the following years succeeded in completing the mapping of the country with primary consideration to the declination. The observations on the repeat stations during the time 1928-1980 allowed development of mathematical formulas for the secular change of the magnetic elements D, H and Z at any arbitrary point in the country.

  20. Report of geomagnetic pulsation indices for space weather applications

    USGS Publications Warehouse

    Xu, Z.; Gannon, Jennifer L.; Rigler, Erin J.

    2013-01-01

    The phenomenon of ultra-low frequency geomagnetic pulsations was first observed in the ground-based measurements of the 1859 Carrington Event and has been studied for over 100 years. Pulsation frequency is considered to be “ultra” low when it is lower than the natural frequencies of the plasma, such as the ion gyrofrequency. Ultra-low frequency pulsations are considered a source of noise in some geophysical analysis techniques, such as aeromagnetic surveys and transient electromagnetics, so it is critical to develop near real-time space weather products to monitor these geomagnetic pulsations. The proper spectral analysis of magnetometer data, such as using wavelet analysis techniques, can also be important to Geomagnetically Induced Current risk assessment.

  1. Long-period geomagnetic pulsations as solar flare precursors

    NASA Astrophysics Data System (ADS)

    Barkhatov, N. A.; Obridko, V. N.; Revunov, S. E.; Snegirev, S. D.; Shadrukov, D. V.; Sheiner, O. A.

    2016-03-01

    We compare long-period pulsations of the horizontal component of the geomagnetic field at intervals that precede extreme solar flares. To this end, we use the wavelet-skeleton technique to process the geomagnetic field disturbances recorded at magnetic stations over a wide geographical range. The synchronization times of wavelet-skeleton spectral distributions of long-period pulsations of geomagnetic oscillations over all magnetic stations are shown as normalized histograms. A few days before an intense solar flare, the histograms show extremes. This means that these extremes can be regarded as flare precursors. The same technique is used to analyze the parameters of near-Earth space. The histograms obtained in this case are free of the aforementioned extrema and, therefore, cannot point to an upcoming flare. The goal of this study is to construct a correlation-spectral method for the short-term prediction of solar flare activity.

  2. F layer positive response to a geomagnetic storm - June 1972

    NASA Technical Reports Server (NTRS)

    Miller, N. J.; Grebowsky, J. M.; Mayr, H. G.; Harris, I.; Tulunay, Y. K.

    1979-01-01

    A circulation model of neutral thermosphere-ionosphere coupling is used to interpret in situ spacecraft measurements taken during a topside midlatitude ionospheric storm. The data are measurements of electron density taken along the circular polar orbit of Ariel 4 at 550 km during the geomagnetically disturbed period June 17-18, 1972. It is inferred that collisional momentum transfer from the disturbed neutral thermosphere to the ionosphere was the dominant midday process generating the positive F-layer storm phase in the summer hemisphere. In the winter hemisphere the positive storm phase drifted poleward in the apparent response to magnetospheric E x B drifts. A summer F-layer positive phase developed at the sudden commencement and again during the geomagnetic main phase; a winter F-layer positive phase developed only during the geomagnetic main phase. The observed seasonal differences in both the onsets and the magnitudes of the positive phases are attributed to the interhemispheric asymmetry in thermospheric dynamics.

  3. Extreme geomagnetic disturbances due to shocks within CMEs

    NASA Astrophysics Data System (ADS)

    Lugaz, N.; Farrugia, C. J.; Huang, C.-L.; Spence, H. E.

    2015-06-01

    We report on features of solar wind-magnetosphere coupling elicited by shocks propagating through coronal mass ejections (CMEs) by analyzing the intense geomagnetic storm of 6 August 1998. During this event, the dynamic pressure enhancement at the shock combined with a simultaneous increase in the southward component of the magnetic field resulted in a large earthward retreat of Earth's magnetopause, which remained close to geosynchronous orbit for more than 4 h. This occurred despite the fact that both shock and CME were weak and relatively slow. Another similar example of a weak shock inside a slow CME resulting in an intense geomagnetic storm is the 30 September 2012 event, which strongly depleted the outer radiation belt. We discuss the potential of shocks inside CMEs to cause large geomagnetic effects at Earth, including magnetopause shadowing.

  4. Error enhancement in geomagnetic models derived from scalar data

    NASA Technical Reports Server (NTRS)

    Stern, D. P.; Bredekamp, J. H.

    1974-01-01

    Models of the main geomagnetic field are generally represented by a scalar potential gamma expanded in a finite number of spherical harmonics. Very accurate observations of F were used, but indications exist that the accuracy of models derived from them is considerably lower. One problem is that F does not always characterize gamma uniquely. It is not clear whether such ambiguity can be encountered in deriving gamma from F in geomagnetic surveys, but there exists a connection, due to the fact that the counterexamples of Backus are related to the dipole field, while the geomagnetic field is dominated by its dipole component. If the models are recovered with a finite error (i.e. they cannot completely fit the data and consequently have a small spurious component), this connection allows the error in certain sequences of harmonic terms in gamma to be enhanced without unduly large effects on the fit of F to the model.

  5. Semiannual variation of the geomagnetic activity and solar wind parameters

    NASA Astrophysics Data System (ADS)

    Orlando, M.; Moreno, G.; Parisi, M.; Storini, M.

    1993-10-01

    The semiannual variation of the geomagnetic activity is investigated in connection with a large set of solar wind and interplanetary magnetic field data (4494 daily averages from 1965 to 1987). Our analysis confirms that the geomagnetic activity (described by the aa index), is mainly modulated by the southward component of the magnetic field (BS), as suggested by Russell and McPherron. On the other hand, it is also found that the solar wind velocity (V) has a relevant role in this phenomenon. In fact, the amplitude of the aa modulation is best correlated with the function BSV2. We also explore the linkage between the annual trend of aa and the sunspot activity (1868-1989), showing that the modulation of the geomagnetic activity follows a more regular pattern during the descending phase of the solar cycle than during the rising and maximum parts.

  6. Reference Assessment

    ERIC Educational Resources Information Center

    Bivens-Tatum, Wayne

    2006-01-01

    This article presents interesting articles that explore several different areas of reference assessment, including practical case studies and theoretical articles that address a range of issues such as librarian behavior, patron satisfaction, virtual reference, or evaluation design. They include: (1) "Evaluating the Quality of a Chat Service"…

  7. Reference Services.

    ERIC Educational Resources Information Center

    Bunge, Charles A.

    1999-01-01

    Discusses library reference services. Topics include the historical development of reference services; instruction in library use, particularly in college and university libraries; guidance; information and referral services and how they differ from traditional question-answering service; and future concerns, including user fees and the planning…

  8. Geomagnetic, cosmogenic and climatic changes across the last geomagnetic reversal from Equatorial Indian Ocean sediments

    NASA Astrophysics Data System (ADS)

    Valet, Jean-Pierre; Bassinot, Franck; Bouilloux, Alexandra; Bourlès, Didier; Nomade, Sébastien; Guillou, Valéry; Lopes, Fernand; Thouveny, Nicolas; Dewilde, Fabien

    2014-07-01

    distribution of tektite abundance was used to deconvolve the 10Be/9Be signal. The results confirm that the beryllium changes are concentrated during the transitional period, thus likely in presence of a multipolar geomagnetic field (or in the vicinity of a geomagnetic pole) that favored the penetration of cosmic rays and consequently increased the 10Be production. The absence of 10Be during the precursor indicates that the present site and the Indonesian ones were far away from a geomagnetic pole and that interlatitudinal atmospheric mixing was limited. The geomagnetic pole positions above the Indonesian sites during the precursor would thus be incompatible with the corresponding inclined dipolar field during this period, and suggest the dominance of low-degree harmonics.

  9. Reference frames and reference networks

    NASA Astrophysics Data System (ADS)

    Bosy, Jaroslaw; Krynski, Jan

    2015-12-01

    The summary of research activities concerning reference frames and reference networks performed in Poland in a period of 2011-2014 is presented. It contains the results of research on implementation of IUGG2011 and IAU2012 resolutions on reference systems, implementation of the ETRS89 in Poland, operational work of permanent IGS/ EUREF stations in Poland, operational work of ILRS laser ranging station in Poland, active GNSS station networks in Poland, maintenance of vertical control in Poland, maintenance and modernization of gravity control, and maintenance of magnetic control in Poland. The bibliography of the related works is given in references.

  10. Alternating light-darkness-influenced human electrocardiographic magnetoreception in association with geomagnetic pulsations.

    PubMed

    Otsuka, K; Oinuma, S; Cornélissen, G; Weydahl, A; Ichimaru, Y; Kobayashi, M; Yano, S; Holmeslet, B; Hansen, T L; Mitsutake, G; Engebretson, M J; Schwartzkopff, O; Halberg, F

    2001-01-01

    Geomagnetic variations of partly interplanetary origin, with cyclic signatures in human affairs and pathology include the incidence of various diseases, regarding which this study of healthy subjects attempted to determine an underlying mechanism by worldwide archival and physiological monitoring, notably of heart rate variability (HRV). In the past half-century, the possible health and other hazards of natural, solar variability-driven temporal variations in the earth's magnetic field have become a controversial subject in view of the inconsistent results. Some well-documented claims of associations between geomagnetic storms and myocardial infarction or stroke have been rejected by a study based on more comprehensive data analyzed by rigorous methods - covering, however, only part of a solar cycle in only part of a hemisphere. It seems possible that inter-solar cycle and geographic variability, if not geographic differences, may account for discrepancies. Herein, we examine the start of a planetary study on any influence of geomagnetic disturbances that are most pronounced in the auroral oval, on human HRV. The magnetic field variations exhibit complex spectra and include the frequency band between 0.001-10 Hz, which is regarded as ultra-low frequency by physicists. Since the 'ultra-low-frequency' range, like other endpoints used in cardiology, refers to much higher frequencies than the about-yearly changes that are here shown to play a role in environmental-organismic interactions revealed by HRV, the current designations used in cardiology are all placed in quotation marks to indicate the need for possible revision. Whether or not this suggestion has an immediate response, we have pointed to a need for the development of instrumentation and software that renders the assessment of circadian, infradian and even infra-annual (truly low frequency) modulations routinely feasible. HRV was examined on the basis of nearly continuous 7-day records by ECG between

  11. Digital Dilemma: Intellectual Property [and] The ERCIM Technical Reference Digital Library [and] International Information Gateway Collaboration [and] The Standards Fora for Online Education.

    ERIC Educational Resources Information Center

    Gladney, Henry M.; Andreoni, Antonella; Baldacci, Maria Bruna; Biagioni, Stefania; Carlesi, Carlo; Castelli, Donatella; Pagano, Pasquale; Peters, Carol; Pisani, Serena; Dempsey, Lorcan; Gardner, Tracy; Day, Michael; van der Werf, Titia; Bacsich, Paul; Heath, Andy; Lefrere, Paul; Miller, Paul; Riley, Kevin

    1999-01-01

    Includes four articles that discuss the impact of the emerging digital information infrastructure on intellectual property; the implementation of a digital library for a European consortium of national research institutions; an international information gateway collaboration; and developing standards for the description and sharing of educational…

  12. 12 CFR 204.125 - Foreign, international, and supranational entities referred to in §§ 204.2(c)(1)(iv)(E) and 204.8...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ....2(c)(1)(iv)(E) and 204.8(a)(2)(i)(B)(5) are: Europe Bank for International Settlements. European Atomic Energy Community. European Central Bank. European Coal and Steel Community. The European Communities. European Development Fund. European Economic Community. European Free Trade Association....

  13. 12 CFR 204.125 - Foreign, international, and supranational entities referred to in §§ 204.2(c)(1)(iv)(E) and 204.8...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ....2(c)(1)(iv)(E) and 204.8(a)(2)(i)(B)(5) are: Europe Bank for International Settlements. European Atomic Energy Community. European Central Bank. European Coal and Steel Community. The European Communities. European Development Fund. European Economic Community. European Free Trade Association....

  14. Dimensions of the Community College: International, Intercultural, and Multicultural Perspectives. Garland Studies in Higher Education, Volume 6. Garland Reference Library of Social Science, Volume 1075.

    ERIC Educational Resources Information Center

    Raby, Rosalind Latiner, Ed.; Tarrow, Norma, Ed.

    This two-part monograph provides a theoretical and practical analyses of intercultural and multicultural education programs. The first part describes inter- and multicultural educational programs in the United States and Canada and includes the following eight chapters: "International, Intercultural, and Multicultural Dimensions of Community…

  15. GEOMAGNETIC REVERSALS DRIVEN BY ABRUPT SEA LEVEL CHANGES

    SciTech Connect

    Muller, R.A.; Morris, D.E.

    1986-10-01

    Changes in the moment of inertia of the earth, brought about by the redistribution of ocean water from the tropics to ice at high latitudes, couple energy from the spin of the earth into convection in the liquid core. This mechanism may help provide the driving energy for the earth's dynamo. Sufficiently rapid ocean level changes can disrupt the dynamo, resulting (in half of the cases) in a geomagnetic field reversal. The model can account for the previously mysterious correlation reported between geomagnetic reversals and mass extinctions.

  16. Effects of a geomagnetic storm on thermospheric circulation. Master's thesis

    SciTech Connect

    Brinkman, D.G.

    1987-01-01

    The motions of the thermosphere and its interactions with the ionosphere during a geomagnetic storm are of current interest to space scientists. A two-dimensional model was used to simulate the thermospheric response to the impulsive high-latitude heating associated with a geomagnetic storm. The storm-induced motions can be characterized by an initial period of transient waves followed by the development of a mean circulation. These motions generate an electrical-current system that is on the same order of magnitude as, and in the opposite sense to the normal s/sub q/ current system. Model-simulated winds and electrical currents were then compared to observations.

  17. The Lewis Research Center geomagnetic substorm simulation facility

    NASA Technical Reports Server (NTRS)

    Berkopec, F. D.; Stevens, N. J.; Sturman, J. C.

    1977-01-01

    A simulation facility was established to determine the response of typical spacecraft materials to the geomagnetic substorm environment and to evaluate instrumentation that will be used to monitor spacecraft system response to this environment. Space environment conditions simulated include the thermal-vacuum conditions of space, solar simulation, geomagnetic substorm electron fluxes and energies, and the low energy plasma environment. Measurements for spacecraft material tests include sample currents, sample surface potentials, and the cumulative number of discharges. Discharge transients are measured by means of current probes and oscilloscopes and are verified by a photomultiplier. Details of this facility and typical operating procedures are presented.

  18. 77 FR 22312 - Geomagnetic Disturbances to the Bulk-Power System; Notice of Technical Conference

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-13

    ... Energy Regulatory Commission Geomagnetic Disturbances to the Bulk-Power System; Notice of Technical... Conference on Geomagnetic Disturbances to the Bulk-Power System on Monday, April 30, 2012, from 11 a.m. to 4... issues related to reliability of the Bulk-Power System as affected by geomagnetic disturbances....

  19. Bayesian inference of local geomagnetic secular variation curves: application to archaeomagnetism

    NASA Astrophysics Data System (ADS)

    Lanos, Philippe

    2014-05-01

    The errors that occur at different stages of the archaeomagnetic calibration process are combined using a Bayesian hierarchical modelling. The archaeomagnetic data obtained from archaeological structures such as hearths, kilns or sets of bricks and tiles, exhibit considerable experimental errors and are generally more or less well dated by archaeological context, history or chronometric methods (14C, TL, dendrochronology, etc.). They can also be associated with stratigraphic observations which provide prior relative chronological information. The modelling we propose allows all these observations and errors to be linked together thanks to appropriate prior probability densities. The model also includes penalized cubic splines for estimating the univariate, spherical or three-dimensional curves for the secular variation of the geomagnetic field (inclination, declination, intensity) over time at a local place. The mean smooth curve we obtain, with its posterior Bayesian envelop provides an adaptation to the effects of variability in the density of reference points over time. Moreover, the hierarchical modelling also allows an efficient way to penalize outliers automatically. With this new posterior estimate of the curve, the Bayesian statistical framework then allows to estimate the calendar dates of undated archaeological features (such as kilns) based on one, two or three geomagnetic parameters (inclination, declination and/or intensity). Date estimates are presented in the same way as those that arise from radiocarbon dating. In order to illustrate the model and the inference method used, we will present results based on French, Bulgarian and Austrian datasets recently published.

  20. Sediments fail to record geomagnetic transitions

    NASA Astrophysics Data System (ADS)

    Valet, Jean-Pierre; Meynadier, Laure; Bassinot, Franck; Simon, Quentin; Thouveny, Nicolas

    2016-04-01

    consequence the VGPs follow a simple longitudinal trajectory like expected for a rotation of the dipole. This unrealistic scenario likely results from heavy post-depositional processes that integrated various amounts of pre- and post-transitional magnetic directions within each sample. These results confirm that sediments are mostly inappropriate to extract suitable information about geomagnetic reversals.

  1. Spatial and Temporal Variations in the Geomagnetic Field Determined From the Paleomagnetism of Sediment Cores From Scientific Ocean Drilling

    NASA Astrophysics Data System (ADS)

    Acton, G.

    2014-12-01

    Quantifying the spatial and temporal variations of the main geomagnetic field at Earth's surface is important for understanding underlying geodynamo processes and conditions near the core-mantle boundary. Much of the geomagnetic variability, known as secular variation, occurs on timescales of tens of years to many thousands of years, requiring the use of paleomagnetic observations to derive continuous records of the ancient field, referred to as paleosecular variation (PSV) records. Marine depositional systems where thick sedimentary sections accumulate at high sedimentation rates provide some of the best locations for obtaining long continuous PSV records that can reveal both the short- and long-term changes in the field. Scientific ocean drilling has been successful at recovering many such sections and the paleomagnetic records from these reveal how the amplitude of PSV differs between sites and through time. In this study, several such records cored during Ocean Drilling Program (ODP), Integrated Ocean Drilling Program (IODP), and other cruises from high, mid, and low latitudes will be used to quantify time intervals of low and high PSV, to examine time-average properties of the field, to map spatial variations in the angular dispersion of the virtual geomagnetic pole (VGP), and to assess whether the spatial variation in angular dispersion changes with time.

  2. Ready Reference.

    ERIC Educational Resources Information Center

    Koltay, Emery

    1998-01-01

    Provides publishers' toll-free telephone numbers from "Literary Market Place" and includes distributors and regional toll-free numbers. Also includes information on obtaining International Standard Book Numbers (ISBN), International Standard Serial Numbers (ISSN), and Standard Address Numbers (SAN). (PEN)

  3. Ground-water and surface-water elevations in the Fairbanks International Airport area, Alaska, 1990-96, and selected geohydrologic report references

    USGS Publications Warehouse

    Claar, David V.; Lilly, Michael R.

    1997-01-01

    Ground-water and surface-water elevation data were collected at 61 sites from 1990 to 1996 by the U.S. Geological Survey in cooperation with the Alaska Department of Transportation and Public Facilities, Fairbanks International Airport. Water-surface elevations were measured in 41 ground-water observation wells and at 20 surface-water sites to help characterize the geohydrology of the Fairbanks International Airport area. From 1990 to 1993, data were collected in the vicinity of the former fire-training area at the airport. From 1993 to 1996, the data-collection area was expanded to include the entire airport area. The total number of data-collection sites varied each year because of changing project objectives and increased understanding of the geohydrology in the area.

  4. Mid-Latitude Ionospheric Disturbances Due to Geomagnetic Storms at ISS Altitudes

    NASA Technical Reports Server (NTRS)

    Minow, Joseph I.; Willis, Emily M.; Parker, Linda Neergaard

    2014-01-01

    Spacecraft charging of the International Space Station (ISS) is dominated by the interaction of the high voltage US solar arrays with the F2-region ionospheric plasma environment. We are working to fully understand the charging behavior of the ISS solar arrays and determine how well future charging behavior can be predicted from in-situ measurements of plasma density and temperature. One aspect of this work is a need to characterize the magnitude of electron density and temperature variations that may be encountered at ISS orbital altitudes (approximately 400 km), the latitudes over which they occur, and the time periods for which the disturbances persist. We will present preliminary results from a study of ionospheric disturbances in the "mid-latitude" region defined as the approximately 30 - 60 degree extra-equatorial magnetic latitudes sampled by ISS. The study is focused on geomagnetic storm periods because they are well known drivers for disturbances in the high-latitude and mid-latitude ionospheric plasma. Changes in the F2 peak electron density obtained from ground based ionosonde records are compared to in-situ electron density and temperature measurements from the CHAMP and ISS spacecraft at altitudes near, or above, the F2 peak. Results from a number of geomagnetic storms will be presented and their potential impact on ISS charging will be discussed.

  5. Comparing the jerk with other global models of the geomagnetic field from 1960 to 1978

    NASA Technical Reports Server (NTRS)

    Backus, G. E.; Estes, R. H.; Chinn, D.; Langel, R. A.

    1987-01-01

    About 3300 satellite values of geomagnetic intensity and about 700 observatory values of annual mean magnetic vector components from 1960 to 1978 were fitted by three global models of the geomagnetic field B. Each model includes a spatially constant external field whose time dependence is a constant plus another constant times the Dst index, and each model accepts a time-independent station correction at each observatory. The time dependence of the internal Gauss coefficients is either cubic, quintic, or biquadratic (two independent quadratics, one before and one after January 1, 1970); and g1(0) also has an induced term proportional to the Dst index. The rms residual of the data fit is the same for the cubic and biquadratic models and insignificantly smaller for the quintic model. The quintic and biquadratic models have 1164 adjustable parameters, and the cubic has 1038. At a high level of significance the parameters of the best fitting biquadratic rule out a physical model for the magnetic impulse of 1969 in which the level surfaces of electrical conductivity in the lower mantle are approximately spherical, and the radial magnetic field at the core-mantle boundary goes from one quadratic time dependence to another in a year or less.

  6. Establishing the Geomagnetic Disturbance Benchmark Event for Evaluation of the Space Weather Hazard on Power Grids

    NASA Astrophysics Data System (ADS)

    Pulkkinen, A. A.; Bernabeu, E.; Eichner, J.

    2014-12-01

    The awareness about potential major impact geomagnetically induced currents (GIC) can have on the North American high-voltage power transmission system has prompted Federal Energy Regulatory Commission (FERC) to launch a geomagnetic disturbances (GMD) standards drafting process. The goals of the GMD standards are to quantify and mitigate the GMD hazard on the North American grid. North American Electric Reliability Corporation's (NERC) is coordinating the standards drafting process that is now entering Phase II involving quantification of the impact GIC can have on individual parts of the North American grid. As a part of the Phase II GMD standards drafting process, substantial effort has been made for generating benchmark GMD scenarios. These scenarios that quantify extreme geoelectric field magnitudes and temporal waveforms of the field fluctuations are the foundation for subsequent engineering and impacts analyses. The engineering analyses will include the transmission system voltage stability and transformer heating assessments. The work on the GMD scenarios has been a major collaboration between a number of international entities involved in GMD research and transmission system operations. We will discuss in this paper the key elements of the benchmark GMD generation process and show the latest results from our work on the topic.

  7. On cosmic rays flux variations in midlatitudes and their relations to geomagnetic and atmospheric conditions

    NASA Astrophysics Data System (ADS)

    Morozova, Anna; Blanco, Juan Jose; Mendes Ribeiro, Paulo Fernando

    The cosmic rays flux is globally modulated by the solar cycle and shows anti-correlation with the sunspot number. Near to the Earth it is modulated by the solar wind and the Earth's magnetic field. The analysis of the secondary cosmic rays produced when they interact in the low stratosphere allows extracting information about solar wind structures surrounding Earth's orbit, the magnetic field of the Earth and the temperature of the stratosphere. Recently, a new cosmic ray detector, the TRAGALDABAS, composed by RPC (Resistive Plate Chamber) planes, has been developed and installed to go deeper into the understanding of the cosmic rays arriving to the Earth surface. An international collaboration has been organized for keeping the detector operative and for analyzing the data. Here we present the analysis of the cosmic rays flux variations measured by two cosmic rays detectors of different types located in Spain (Castilla-La Mancha Neutron Monitor - CaLMa - in Guadalajara and TRAGALDABAS in Santiago de Compostela) and their comparison to changes both in the geomagnetic field components measured by the Coimbra Geomagnetic Observatory (Portugal) and in the atmospheric conditions (tropo- and stratosphere) measured by Spanish and Portuguese meteorological stations. The study is focused on a number of recent cosmic rays events and pays specific attention to the comparison of the CaLMa series and the preliminary TRAGALDABAS data.

  8. Heat treatment and the use of additives to improve the stability of paralytic shellfish poisoning toxins in shellfish tissue reference materials for internal quality control and proficiency testing.

    PubMed

    Burrell, Stephen; Clion, Valentin; Auroy, Virginie; Foley, Barry; Turner, Andrew D

    2015-06-01

    The need for homogenous reference materials stable for paralytic shellfish toxins is vital for the monitoring and quality assurance of these potent neurotoxins in shellfish. Two stabilisation techniques were investigated, heat treatment through autoclaving and the addition of preserving additives into the tissue matrix. Short and long-term stability experiments as well as homogeneity determination were conducted on materials prepared by both techniques in comparison with an untreated control using two LC-FLD methods. Both techniques improved the stability of the matrix and the PSP toxins present compared to the controls. A material was prepared using the combined techniques of heat treatment followed by spiking with additives and data is presented from this optimised reference material as used over a two year period in the Irish national monitoring program and in a development exercise as part of a proficiency testing scheme operated by QUASIMEME (Quality Assurance of Information for Marine Environmental Monitoring in Europe) since 2011. The results were indicative of the long-term stability of the material as evidenced through consistent assigned values in the case of the proficiency testing scheme and a low relative standard deviation of 10.5% for total toxicity data generated over 24 months. PMID:25816999

  9. Solar Activity, Different Geomagnetic Activity Levels and Acute Myocardial Infarction

    NASA Astrophysics Data System (ADS)

    Dimitrova, Svetla; Jordanova, Malina; Stoilova, Irina; Taseva, Tatiana; Maslarov, Dimitar

    Results on revealing a possible relationship between solar activity (SA) and geomagnetic activity (GMA) and acute myocardial infarction (AMI) morbidity are presented. Studies were based on medical data covering the period from 1.12.1995 to 31.12.2004 and concerned daily distribution of patients with AMI diagnose (in total 1192 cases) from Sofia region on the day of admission at the hospital. Analysis of variance (ANOVA) was applied to check the significance of GMA intensity effect and the type of geomagnetic storms, those caused by Magnetic Clouds (MC) and by High Speed Solar Wind Streams (HSSWS), on AMI morbidity. Relevant correlation coefficients were calculated. Results revealed statistically significant positive correlation between considered GMA indices and AMI. ANOVA revealed that AMI number was signifi- cantly increased from the day before (-1st) till the day after (+1st) geomagnetic storms with different intensities. Geomagnetic storms caused by MC were related to significant increase of AMI number in comparison with the storms caused by HSSWS. There was a trend for such different effects even on -1st and +1st day.

  10. Particle acceleration from reconnection in the geomagnetic tail

    SciTech Connect

    Birn, J.; Borovsky, J.E.; Thomsen, M.F.; McComas, D.J.; Reeves, G.D.; Belian, R.D.; Hesse, M.; Schindler, K.

    1997-08-01

    Acceleration of charged particles in the near geomagnetic tail, associated with a dynamic magnetic reconnection process, was investigated by a combined effort of data analysis, using Los Alamos data from geosynchronous orbit, MHD modeling of the dynamic evolution of the magnetotail, and test particle tracing in the electric and magnetic fields obtained from the MHD simulation.

  11. Permutation Entropy Analysis of Geomagnetic Indices Time Series

    NASA Astrophysics Data System (ADS)

    De Michelis, Paola; Consolini, Giuseppe

    2013-04-01

    The Earth's magnetospheric dynamics displays a very complex nature in response to solar wind changes as widely documented in the scientific literature. This complex dynamics manifests in various physical processes occurring in different regions of the Earth's magnetosphere as clearly revealed by previous analyses on geomagnetic indices (AE-indices, Dst, Sym-H, ....., etc.). One of the most interesting features of the geomagnetic indices as proxies of the Earth's magnetospheric dynamics is the multifractional nature of the time series of such indices. This aspect has been interpreted as the occurrence of intermittence and dynamical phase transition in the Earth's magnetosphere. Here, we investigate the Markovian nature of different geomagnetic indices (AE-indices, Sym-H, Asy-H) and their fluctuations by means of Permutation Entropy Analysis. The results clearly show the non-Markovian and different nature of the distinct sets of geomagnetic indices, pointing towards diverse underlying physical processes. A discussion in connection with the nature of the physical processes responsible of each set of indices and their multifractional character is attempted.

  12. Surface electric fields for North America during historical geomagnetic storms

    USGS Publications Warehouse

    Wei, Lisa H.; Homeier, Nichole; Gannon, Jennifer L.

    2013-01-01

    To better understand the impact of geomagnetic disturbances on the electric grid, we recreate surface electric fields from two historical geomagnetic storms—the 1989 “Quebec” storm and the 2003 “Halloween” storms. Using the Spherical Elementary Current Systems method, we interpolate sparsely distributed magnetometer data across North America. We find good agreement between the measured and interpolated data, with larger RMS deviations at higher latitudes corresponding to larger magnetic field variations. The interpolated magnetic field data are combined with surface impedances for 25 unique physiographic regions from the United States Geological Survey and literature to estimate the horizontal, orthogonal surface electric fields in 1 min time steps. The induced horizontal electric field strongly depends on the local surface impedance, resulting in surprisingly strong electric field amplitudes along the Atlantic and Gulf Coast. The relative peak electric field amplitude of each physiographic region, normalized to the value in the Interior Plains region, varies by a factor of 2 for different input magnetic field time series. The order of peak electric field amplitudes (largest to smallest), however, does not depend much on the input. These results suggest that regions at lower magnetic latitudes with high ground resistivities are also at risk from the effect of geomagnetically induced currents. The historical electric field time series are useful for estimating the flow of the induced currents through long transmission lines to study power flow and grid stability during geomagnetic disturbances.

  13. An empirical model of the quiet daily geomagnetic field variation

    USGS Publications Warehouse

    Yamazaki, Y.; Yumoto, K.; Cardinal, M.G.; Fraser, B.J.; Hattori, P.; Kakinami, Y.; Liu, J.Y.; Lynn, K.J.W.; Marshall, R.; McNamara, D.; Nagatsuma, T.; Nikiforov, V.M.; Otadoy, R.E.; Ruhimat, M.; Shevtsov, B.M.; Shiokawa, K.; Abe, S.; Uozumi, T.; Yoshikawa, A.

    2011-01-01

    An empirical model of the quiet daily geomagnetic field variation has been constructed based on geomagnetic data obtained from 21 stations along the 210 Magnetic Meridian of the Circum-pan Pacific Magnetometer Network (CPMN) from 1996 to 2007. Using the least squares fitting method for geomagnetically quiet days (Kp ??? 2+), the quiet daily geomagnetic field variation at each station was described as a function of solar activity SA, day of year DOY, lunar age LA, and local time LT. After interpolation in latitude, the model can describe solar-activity dependence and seasonal dependence of solar quiet daily variations (S) and lunar quiet daily variations (L). We performed a spherical harmonic analysis (SHA) on these S and L variations to examine average characteristics of the equivalent external current systems. We found three particularly noteworthy results. First, the total current intensity of the S current system is largely controlled by solar activity while its focus position is not significantly affected by solar activity. Second, we found that seasonal variations of the S current intensity exhibit north-south asymmetry; the current intensity of the northern vortex shows a prominent annual variation while the southern vortex shows a clear semi-annual variation as well as annual variation. Thirdly, we found that the total intensity of the L current system changes depending on solar activity and season; seasonal variations of the L current intensity show an enhancement during the December solstice, independent of the level of solar activity. Copyright 2011 by the American Geophysical Union.

  14. 78 FR 30747 - Reliability Standards for Geomagnetic Disturbances

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-23

    ... Reliability Corporation (NERC), the Commission-certified Electric Reliability Organization, to submit to the... Commission directs the North American Electric Reliability Corporation (NERC), the Commission-certified... Report: Effects of Geomagnetic Disturbances on the Bulk Power System at ii (February 2012) (NERC...

  15. An empirical model of the quiet daily geomagnetic field variation

    NASA Astrophysics Data System (ADS)

    Yamazaki, Y.; Yumoto, K.; Cardinal, M. G.; Fraser, B. J.; Hattori, P.; Kakinami, Y.; Liu, J. Y.; Lynn, K. J. W.; Marshall, R.; McNamara, D.; Nagatsuma, T.; Nikiforov, V. M.; Otadoy, R. E.; Ruhimat, M.; Shevtsov, B. M.; Shiokawa, K.; Abe, S.; Uozumi, T.; Yoshikawa, A.

    2011-10-01

    An empirical model of the quiet daily geomagnetic field variation has been constructed based on geomagnetic data obtained from 21 stations along the 210 Magnetic Meridian of the Circum-pan Pacific Magnetometer Network (CPMN) from 1996 to 2007. Using the least squares fitting method for geomagnetically quiet days (Kp ≤ 2+), the quiet daily geomagnetic field variation at each station was described as a function of solar activity SA, day of year DOY, lunar age LA, and local time LT. After interpolation in latitude, the model can describe solar-activity dependence and seasonal dependence of solar quiet daily variations (S) and lunar quiet daily variations (L). We performed a spherical harmonic analysis (SHA) on these S and L variations to examine average characteristics of the equivalent external current systems. We found three particularly noteworthy results. First, the total current intensity of the S current system is largely controlled by solar activity while its focus position is not significantly affected by solar activity. Second, we found that seasonal variations of the S current intensity exhibit north-south asymmetry; the current intensity of the northern vortex shows a prominent annual variation while the southern vortex shows a clear semi-annual variation as well as annual variation. Thirdly, we found that the total intensity of the L current system changes depending on solar activity and season; seasonal variations of the L current intensity show an enhancement during the December solstice, independent of the level of solar activity.

  16. New insights on geomagnetic storms from observations and modeling

    SciTech Connect

    Jordanova, Vania K

    2009-01-01

    Understanding the response at Earth of the Sun's varying energy output and forecasting geomagnetic activity is of central interest to space science, since intense geomagnetic storms may cause severe damages on technological systems and affect communications. Episodes of southward (Bzgeomagnetic conditions are associated either with coronal mass ejections (CMEs) and possess long and continuous negative IMF Bz excursions, or with high speed solar wind streams (HSS) whose geoeffectiveness is due to IMF Bz profiles fluctuating about zero with various amplitudes and duration. We show examples of ring current simulations during two geomagnetic storms representative of each interplanetary condition with our kinetic ring current atmosphere interactions model (RAM), and investigate the mechanisms responsible for trapping particles and for causing their loss. We find that periods of increased magnetospheric convection coinciding with enhancements of plasma sheet density are needed for strong ring current buildup. During the HSS-driven storm the convection potential is highly variable and causes small sporadic injections into the ring current. The long period of enhanced convection during the CME-driven storm causes a continuous ring current injection penetrating to lower L shells and stronger ring current buildup.

  17. Geomagnetic Variations and Their Possible Effects on System Earth

    NASA Astrophysics Data System (ADS)

    Glassmeier, K.

    2003-12-01

    The Earth magnetic field exhibits a variety of temporal variations with time scales ranging from a few seconds up to millions of years. The most pronounced variation is certainly a polarity transition during which the geomagnetic field strength decays down to about 10-20 % of its current value. A question of immediate interest is whether and in which way System Earth reacts on such a dramatic event. First the magnetosphere changes its size and shape. Due to the decreasing geomagnetic field the magnetopause is located much closer to the surface of the Earth. If the field exhibits strong quadrupole components magnetic reconnection can happen in the northern dayside magnetosphere with the southern hemisphere featuring a closed magnetosphere. Also the magnetotail structure changes drastically. Energetic particle entry occurs not only in dipolar cap regions but over much enlarged areas. As the ionospheric conductivity depends on the geomagnetic field strength first estimates furthermore indicate that externally driven geomagnetic variations are stronger during times of a polarity transition. The weaker field also makes the middle atmosphere much more sensitive to energetic particle events and large natural ozone holes are very likely during polarity transitions as first model calculations indicate.

  18. Possible helio-geomagnetic activity influence on cardiological cases

    NASA Astrophysics Data System (ADS)

    Katsavrias, Christos

    Eruptive solar events as flares and coronal mass ejections (CMEs) occur during solar activ-ity periods. Energetic particles, fast solar wind plasma and electromagnetic radiation pass through interplanetary space, arrive on Earth's ionosphere-magnetosphere and produce various disturbances. It is well known the negative influence of geomagnetic substorms on the human technological applications on geospace. During the last 25 years, many studies concerning the possible influence on the human health are published. Increase of the Acute Coronary Syn-dromes and disorders of the Cardiac Rhythm, increase of accidents as well as neurological and psychological disorders (e.g. increase of suicides) during or near to the geomagnetic storms time interval are reported. In this study, we research the problem in Greece, focusing on patients with Acute Myocardial Infraction, hospitalized in the 2nd Cardiological Department of the General Hospital of Nikaea (Piraeus City), for the time interval 1997-2007 (23rd solar cycle) and also to the arrival of emergency cardiological cases to Emergency Department of two greek hospitals, the General Hospital of Lamia City and the General Hospital of Veria City during the selected months, with or without helio-geomagnetic activity, of the 23rd solar cycle. Increase of cases is recorded during the periods with increase helio-geomagnetic activity. The necessity of continuing the research for a longer period and with a bigger sample is high; so as to exact more secure conclusions.

  19. Geomagnetic cutoffs: a review for space dosimetry applications.

    PubMed

    Smart, D F; Shea, M A

    1994-10-01

    The earth's magnetic field acts as a shield against charged particle radiation from interplanetary space, technically described as the geomagnetic cutoff. The cutoff rigidity problem (except for the dipole special case) has "no solution in closed form". The dipole case yields the Stormer equation which has been repeatedly applied to the earth in hopes of providing useful approximations of cutoff rigidities. Unfortunately the earth's magnetic field has significant deviations from dipole geometry, and the Stormer cutoffs are not adequate for most applications. By application of massive digital computer power it is possible to determine realistic geomagnetic cutoffs derived from high order simulation of the geomagnetic field. Using this technique, "world-grids" of directional cutoffs for the earth's surface and for a limited number of satellite altitudes have been derived. However, this approach is so expensive and time consuming it is impractical for most spacecraft orbits, and approximations must be used. The world grids of cutoff rigidities are extensively used as lookup tables, normalization points and interpolation aids to estimate the effective geomagnetic cutoff rigidity of a specific location in space. We review the various options for estimating the cutoff rigidity for earth-orbiting satellites. PMID:11540027

  20. ISS Plasma Contactor Units Operations During Strong Geomagnetic Activity

    NASA Astrophysics Data System (ADS)

    Alred, J.; Mikatarian, R.; Barsamian, H.; Minow, J.; Koontz, S.

    2003-12-01

    The large structure and high voltage arrays of the ISS represent a complex system that interacts with the Earth's ionosphere. To mitigate spacecraft charging problems on the ISS, two Plasma Contactor Units discharge ionized xenon gas to "clamp" the potential of the ISS with respect to the low Earth orbit plasma. The Plasma Interaction Model, a model of ISS plasma interaction developed from the basic physics of the interaction phenomena, includes magnetic induction effects, plasma temperature and density effects, interaction of the high voltage solar arrays with ionospheric plasma, and accounts for other conductive areas on the ISS. To augment this model, the PCU discharge current has been monitored for the ISS in a variety of flight attitudes as well as during the annual seasons. A review of the PCU discharge currents shows a correlation to the geomagnetic activity. The variation in the PCU discharge current during strong geomagnetic activity will be presented. Also, the PCU discharge currents during periods of low geomagnetic activity will be discussed. The presentation will conclude with a comparison of satellite plasma measurements during different stages of geomagnetic activity.