Sample records for tec vaatab toiduainetstuse

  1. Comparison with IRI-PLUS and IRI-2012-TEC values of GPS-TEC values

    NASA Astrophysics Data System (ADS)

    Atıcı, Ramazan; Saǧır, Selçuk

    2016-07-01

    This study presents a comparison with IRI-PLUS and IRI-2012 Total Electron Content (TEC) values of Total Electron Content (TEC) values obtained from Ankara station (39,7 N; 32,76 E) of Global Position System (GPS) of Turkey on equinox and solstice days of 2009 year. For all days, it is observed that GPS-TEC values are greater than IRI-2012-TEC values, while IRI-PLUS-TEC values are very close to GPS-TEC values. When GPS-TEC values for both equinoxes are compared, it is seen that TEC values on September equinox are greater than one on March equinox. However, it is observed that GPS-TEC values on June solstice are greater than one on December solstice. Also, the relationship between GPS-TEC values and geomagnetic indexes is investigated.

  2. Total electron content (TEC) variability at Los Alamos, New Mexico: A comparative study: FORTE-derived TEC analysis

    NASA Astrophysics Data System (ADS)

    Huang, Zhen; Roussel-Dupré, Robert

    2005-12-01

    Data collected from Fast On-Orbit Recording of Transient Events (FORTE) satellite-received Los Alamos Portable Pulser (LAPP) signals during 1997-2002 are used to derive the total electron content (TEC) at Los Alamos, New Mexico. The LAPP-derived TECs at Los Alamos are analyzed for diurnal, seasonal, interannual, and 27-day solar cycle variations. Several aspects in deriving TEC are analyzed, including slant to vertical TEC conversion, quartic effects on transionosperic signals, and geomagnetic storm effects on the TEC variance superimposed on the averaged TEC values.

  3. A single-station empirical model for TEC over the Antarctic Peninsula using GPS-TEC data

    NASA Astrophysics Data System (ADS)

    Feng, Jiandi; Wang, Zhengtao; Jiang, Weiping; Zhao, Zhenzhen; Zhang, Bingbing

    2017-02-01

    Compared with regional or global total electron content (TEC) empirical models, single-station TEC empirical models may exhibit higher accuracy in describing TEC spatial and temporal variations for a single station. In this paper, a new single-station empirical total electron content (TEC) model, called SSM-month, for the O'Higgins Station in the Antarctic Peninsula is proposed by using Global Positioning System (GPS)-TEC data from 01 January 2004 to 30 June 2015. The diurnal variation of TEC in the O'Higgins Station may have changing features in different months, sometimes even in opposite forms, because of ionospheric phenomena, such as the Mid-latitude Summer Nighttime Anomaly (MSNA). To avoid the influence of different diurnal variations, the concept of monthly modeling is proposed in this study. The SSM-month model, which is established by month (including 12 submodels that correspond to the 12 months), can effectively describe the diurnal variation of TEC in different months. Each submodel of the SSM-month model exhibits good agreement with GPS-TEC input data. Overall, the SSM-month model fits the input data with a bias of 0.03 TECU (total electron content unit, 1 TECU = 1016 el m-2) and a standard deviation of 2.78 TECU. This model, which benefits from the modeling method, can effectively describe the MSNA phenomenon without implementing any modeling correction. TEC data derived from Center for Orbit Determination in Europe global ionosphere maps (CODE GIMs), International Reference Ionosphere 2012 (IRI2012), and NeQuick are compared with the SSM-month model in the years of 2001 and 2015-2016. Result shows that the SSM-month model exhibits good consistency with CODE GIMs, which is better than that of IRI2012 and NeQuick, in the O'Higgins Station on the test days.

  4. GNSS Derived Ionospheric TEC Observed Through Different TEC Calibration Techniques in the Brazilian Sector

    NASA Astrophysics Data System (ADS)

    Becker-Guedes, F.; Carmo, C. S.; Camargo, P. O.; Monico, J. F. G.; Nicoli Candido, C. M.

    2017-12-01

    Global Navigation Satellite System (GNSS) is becoming a reliable tool for use in air navigation systems. Its use as the main technology for determination of airplanes positioning has various economic and logistic benefits but it depends strongly on the ionospheric layer influences. The Brazilian sector ionosphere, mainly over the equatorial ionization anomaly (EIA), presents remarkable errors in the GNSS signal as compared to North America and Europe. In order to study the total electron content latitudinal variation of the Brazilian ionosphere we used a pair of GNSS receivers on the ground, one located in the equatorial region (Sao Luis) and other in the southern crest of the EIA (Cachoeira Paulista), to collect the GNSS observables and calculate the vertical TEC using different methods that has proven to work well to describe the ionospheric behavior in the North America and in Europe. We compared this results with a modified Nagoya TEC calculation method used by the EMBRACE (Estudo e Monitoramento BRAsileiro do Clima Espacial - Brazilian Study and Monitoring of Space Weather) program. This work intends to follow the performance of different TEC tuning methods to evaluate the spurious effects of the ionospheric EIA gradients in the TEC determination under typical conditions of the low-latitudes ionosphere in the Brazilian sector. The calculated TEC under different solar cycle conditions, geomagnetic activity, and seasonal variations show deviations in the performance of each method and stress the importance of well adjust the GNSS observations to local conditions in order to optimize the TEC evaluation. This study contributes to a better understanding of local GNSS signal errors in the global intent of offering conditions to improve the accuracy, integrity, availability, and continuity requirements for the use of GNSS for air navigation in South America.

  5. The NASA thermionic-conversion (TEC-ART) program

    NASA Technical Reports Server (NTRS)

    Morris, J. F.

    1977-01-01

    The current emphasis is on out-of-core thermionic conversion (TEC). The additional degrees of freedom offer new potentialities, but high-temperature material effects determine the level and lifetime of TEC performance: New electrodes not only raise power outputs but also maintain them regardless of emitter-vapor deposition on collectors. In addition, effective electrodes serve compatibly with hot-shell alloys. Space TEC withstands external and internal high-temperature vaporization problems, and terrestrial TEC tolerates hot corrosive atmospheres outside and near-vacuum inside. Finally, reduction of losses between converter electrodes is essential even though rather demanding geometries appear to be required for some modes of enhanced operation.

  6. Comparison of GPS derived TEC with the TEC predicted by IRI 2012 model in the southern Equatorial Ionization Anomaly crest within the Eastern Africa region

    NASA Astrophysics Data System (ADS)

    Sulungu, Emmanuel D.; Uiso, Christian B. S.; Sibanda, Patrick

    2018-04-01

    We have compared the TEC obtained from the IRI-2012 model with the GPS derived TEC data recorded within southern crest of the EIA in the Eastern Africa region using the monthly means of the 5 international quiet days for equinoxes and solstices months for the period of 2012 - 2013. GPS-derived TEC data have been obtained from the Africa array and IGS network of ground based dual-frequency GPS receivers from four stations (Kigali (1.95°S, 30.09°E; Geom. Lat. 11.63°S), Malindi (2.99°S, 40.19°E; Geom. Lat. 12.42°S), Mbarara (0.60°S, 30.74°E; Geom. Lat. 10.22°S) and Nairobi (1.22°S, 36.89°E; Geom. Lat. 10.69°S)) located within the EIA crest in this region. All the three options for topside Ne of IRI-2012 model and ABT-2009 for bottomside thickness have been used to compute the IRI TEC. Also URSI coefficients were considered in this study. These results are compared with the TEC estimated from GPS measurements. Correlation Coefficients between the two sets of data, the Root-Mean Square Errors (RMSE) of the IRI-TEC from the GPS-TEC, and the percentage RMSE of the IRI-TEC from the GPS-TEC have been computed. Our general results show that IRI-2012 model with all three options overestimates the GPS-TEC for all seasons and at all stations, and IRI-2001 overestimates GPS-TEC more compared with other options. IRI-Neq and IRI-01-corr are closely matching in most of the time. The observation also shows that, GPS TEC are underestimated by TEC from IRI model during noon hours, especially during equinoctial months. Further, GPS-TEC values and IRI-TEC values using all the three topside Ne options show very good correlation (above 0.8). On the other hand, the TEC using IRI-Neq and IRI-01- corr had smaller deviations from the GPS-TEC compared to the IRI-2001.

  7. Space Weather Activities of IONOLAB Group: IONOLAB-TEC

    NASA Astrophysics Data System (ADS)

    Arikan, F.; Sezen, U.; Arikan, O.; Ugurlu, O.; Nayir, H.

    2009-04-01

    Space Weather (SW) is the concept of changing environmental conditions in outer space and affect Earth and its technological systems. SW is a consequence of the solar activities and the coupling of solar energy on Earth's atmosphere due to the Earth's magnetic field. The monitoring and prediction of SW has utmost importance for HF communication, Satellite communication, navigation and guidance systems, Low Earth Orbit (LEO) satellite systems, Space Craft exit and entry into the atmosphere. Ionosphere is the plasma layer of the atmosphere that is ionized by solar radiation and it is a key player of SW. Ionosphere is a temporally and spatially varying, dispersive, anisotropic and inhomogeneous medium that is characterized primarily by its electron density distribution. IONOLAB is a group of researchers of various disciplines, getting together to handle challenges of the Earth's ionosphere. The team has researchers from Hacettepe University and Bilkent University, Department of Electrical and Electronics Engineering and General Command of Mapping of Turkish Army. One of the most important contributions of IONOLAB group is the automated web-based computation service for Total Electron Content (TEC). TEC corresponds to the line integral of electron density distribution on a given path. TEC can also be expressed as the amount of free electrons within 1 m2 cross-sectional area of the cylinder on the ray path. Global Position System (GPS) provides a cost-effective medium for monitoring of ionosphere using the signals recorded by stationary GPS receivers in estimating TEC. IONOLAB group has developed IONOLAB-TEC for reliable and robust estimates for all latitudes and both calm and disturbed days by using RINEX, IONEX and satellite ephemeris data provided from the IGS centers. IONOLAB-TEC consists of a regularized signal estimation algorithm which combines signals from all GPS satellites for a given instant and a given receiver, for a desired time period or for 24 hours

  8. TEC Variations Over Korean Peninsula During Magnetic Storm

    NASA Astrophysics Data System (ADS)

    Ji, E.-Y.; Choi, B.-K.; Kim, K.-H.; Lee, D.-H.; Cho, J.-H.; Chung, J.-K.; Park, J.-U.

    2008-03-01

    By analyzing the observations from a number of ground- and space-based instruments, including ionosonde, magnetometers, and ACE interplanetary data, we examine the response of the ionospheric TEC over Korea during 2003 magnetic storms. We found that the variation of vertical TEC is correlated with the southward turning of the interplanetary magnetic field B_z. It is suggested that the electric fields produced by the dynamo process in the high-latitude region and the prompt penetration in the low-latitude region are responsible for TEC increases. During the June 16 event, dayside TEC values increase more than 15%. And the ionospheric F2-layer peak height (hmF2) was ˜300km higher and the vertical E×B drift (estimated from ground-based magnetometer equatorial electrojet delta H) showed downward drift, which may be due to the ionospheric disturbance dynamo electric field produced by the large amount of energy dissipation into high-latitude regions. In contr! ast, during November 20 event, the nightside TEC increases may be due to the prompt penetration westward electric field. The ionospheric F2-layer peak height was below 200km and the vertical E×B drift showed downward drift. Also, a strong correlation is observed between enhanced vertical TEC and enhanced interplanetary electric field. It is shown that, even though TEC increases are caused by the different processes, the electric field disturbances in the ionosphere play an important role in the variation of TEC over Korea.

  9. Thermionic Energy Conversion (TEC) topping thermoelectrics

    NASA Technical Reports Server (NTRS)

    Morris, J. F.

    1981-01-01

    Performance expectations for thermionic and thermoelectric energy conversion systems are reviewed. It is noted that internal radiation effects diminish thermoelectric figures of merit significantly at 1000 K and substantially at 2000 K; the effective thermal conductivity contribution of intrathermoelectric radiative dissipation increases with the third power of temperature. It is argued that a consideration of thermoelectric power generation with high temperature heat sources should include utilization of thermionic energy conversion (TEC) topping thermoelectrics. However TEC alone or TEC topping more efficient conversion systems like steam or gas turbines, combined cycles, or Stirling engines would be more desirable generally.

  10. Global empirical model of TEC response to geomagnetic activity

    NASA Astrophysics Data System (ADS)

    Mukhtarov, P.; Andonov, B.; Pancheva, D.

    2013-10-01

    global total electron content (TEC) model response to geomagnetic activity described by the Kp index is built by using the Center for Orbit Determination of Europe (CODE) TEC data for a full 13 years, January 1999 to December 2011. The model describes the most probable spatial distribution and temporal variability of the geomagnetically forced TEC anomalies assuming that these anomalies at a given modified dip latitude depend mainly on the Kp index, local time (LT), and longitude. The geomagnetic anomalies are expressed by the relative deviation of TEC from its 15 day median and are denoted as rTEC. The rTEC response to the geomagnetic activity is presented by a sum of two responses with different time delay constants and different signs of the cross-correlation function. It has been found that the mean dependence of rTEC on Kp index can be expressed by a cubic function. The LT dependence of rTEC is described by Fourier time series which includes the contribution of four diurnal components with periods 24, 12, 8, and 6 h. The rTEC dependence on longitude is presented by Fourier series which includes the contribution of zonal waves with zonal wave numbers up to 6. In order to demonstrate how the model is able to reproduce the rTEC response to geomagnetic activity, three geomagnetic storms at different seasons and solar activity conditions are presented. The model residuals clearly reveal two types of the model deviation from the data: some underestimation of the largest TEC response to the geomagnetic activity and randomly distributed errors which are the data noise or anomalies generated by other sources. The presented TEC model fits to the CODE TEC input data with small negative bias of -0.204, root mean squares error RMSE = 4.592, and standard deviation error STDE = 4.588. The model offers TEC maps which depend on geographic coordinates (5° × 5° in latitude and longitude) and universal time (UT) at given geomagnetic activity and day of the year. It could be

  11. The synthesis of ternary acetylides with tellurium: Li 2 TeC 2 and Na 2 TeC 2

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

    Németh, Károly; Unni, Aditya K.; Kalnmals, Christopher

    The synthesis of ternary acetylides Li 2TeC 2 and Na 2TeC 2 is presented as the first example of ternary acetylides with metalloid elements instead of transition metals. The synthesis was carried out by the direct reaction of the corresponding bialkali acetylides with tellurium powder in liquid ammonia. Alternatively, the synthesis of Na 2TeC 2 was also carried out by the direct reaction of tellurium powder and two equivalents of NaC 2H in liquid ammonia leading to Na 2TeC 2 and acetylene gas through an equilibrium containing the assumed NaTeC 2H molecules besides the reactants and the products. The resultingmore » disordered crystalline materials were characterized by X-ray diffraction and Raman spectroscopy. Implications of these new syntheses on the synthesis of other ternary acetylides with metalloid elements and transition metals are also discussed.« less

  12. V-TECS Guide for Medical Assistant.

    ERIC Educational Resources Information Center

    South Carolina State Dept. of Education, Columbia. Office of Vocational Education.

    This V-TECS (Vocational-Technical Consortium of States) Guide is an extension or continuation of the V-TECS catalog for the occupation of medical assistant. The guide is designed to help South Carolina teachers to promote the art of learning while teaching subject matter. The guide addresses the three domains of learning: psychomotor, cognitive,…

  13. Local TEC modelling and forecasting using neural networks

    NASA Astrophysics Data System (ADS)

    Tebabal, A.; Radicella, S. M.; Nigussie, M.; Damtie, B.; Nava, B.; Yizengaw, E.

    2018-07-01

    Modelling the Earth's ionospheric characteristics is the focal task for the ionospheric community to mitigate its effect on the radio communication, and satellite navigation. However, several aspects of modelling are still challenging, for example, the storm time characteristics. This paper presents modelling efforts of TEC taking into account solar and geomagnetic activity, time of the day and day of the year using neural networks (NNs) modelling technique. The NNs have been designed with GPS-TEC measured data from low and mid-latitude GPS stations. The training was conducted using the data obtained for the period from 2011 to 2014. The model prediction accuracy was evaluated using data of year 2015. The model results show that diurnal and seasonal trend of the GPS-TEC is well reproduced by the model for the two stations. The seasonal characteristics of GPS-TEC is compared with NN and NeQuick 2 models prediction when the latter one is driven by the monthly average value of solar flux. It is found that NN model performs better than the corresponding NeQuick 2 model for low latitude region. For the mid-latitude both NN and NeQuick 2 models reproduce the average characteristics of TEC variability quite successfully. An attempt of one day ahead forecast of TEC at the two locations has been made by introducing as drivers previous day solar flux and geomagnetic index values. The results show that a reasonable day ahead forecast of local TEC can be achieved.

  14. Local TEC Modelling and Forecasting using Neural Networks

    NASA Astrophysics Data System (ADS)

    Tebabal, A.; Radicella, S. M.; Nigussie, M.; Damtie, B.; Nava, B.; Yizengaw, E.

    2017-12-01

    Abstract Modelling the Earth's ionospheric characteristics is the focal task for the ionospheric community to mitigate its effect on the radio communication, satellite navigation and technologies. However, several aspects of modelling are still challenging, for example, the storm time characteristics. This paper presents modelling efforts of TEC taking into account solar and geomagnetic activity, time of the day and day of the year using neural networks (NNs) modelling technique. The NNs have been designed with GPS-TEC measured data from low and mid-latitude GPS stations. The training was conducted using the data obtained for the period from 2011 to 2014. The model prediction accuracy was evaluated using data of year 2015. The model results show that diurnal and seasonal trend of the GPS-TEC is well reproduced by the model for the two stations. The seasonal characteristics of GPS-TEC is compared with NN and NeQuick 2 models prediction when the latter one is driven by the monthly average value of solar flux. It is found that NN model performs better than the corresponding NeQuick 2 model for low latitude region. For the mid-latitude both NN and NeQuick 2 models reproduce the average characteristics of TEC variability quite successfully. An attempt of one day ahead forecast of TEC at the two locations has been made by introducing as driver previous day solar flux and geomagnetic index values. The results show that a reasonable day ahead forecast of local TEC can be achieved.

  15. Potentialities of TEC topping: A simplified view of parametric effects

    NASA Technical Reports Server (NTRS)

    Morris, J. F.

    1980-01-01

    An examination of the benefits of thermionic-energy-conversion (TEC)-topped power plants and methods of increasing conversion efficiency are discussed. Reductions in the cost of TEC modules yield direct decreases in the cost of electricity (COE) from TEC-topped central station power plants. Simplified COE, overall-efficiency charts presented illustrate this trend. Additional capital-cost diminution results from designing more compact furnaces with considerably increased heat transfer rates allowable and desirable for high temperature TEC and heat pipes. Such improvements can evolve of the protection from hot corrosion and slag as well as the thermal expansion compatibilities offered by silicon-carbide clads on TEC-heating surfaces. Greater efficiencies and far fewer modules are possible with high-temperature, high-power-density TEC: This decreases capital and fuel costs much more and substantially increases electric power outputs for fixed fuel inputs. In addition to more electricity, less pollution, and lower costs, TEC topping used directly in coal-combustion products contributes balance-of-payment gains.

  16. Preliminary study of TEC application in cooling system

    NASA Astrophysics Data System (ADS)

    Sulaiman, A. C.; Amin, N. A. M.; Saidon, M. S.; Majid, M. S. A.; Rahman, M. T. A.; Kazim, M. N. F. M.

    2017-10-01

    Integration of thermoelectric cooling (TEC) within a space cooling system in the lecturer room is studied. The studied area (air conditioned surrounding) is encapsulated with wall, floor, roof, and glass window. TEC module is placed on the glass window. The prototype of the studied compartment is designed using cabin container. The type and number of TEC module are studied and the effects on the cooling performance are analyzed as it is assumed to be tested within an air conditioned lecturer room. The experimental and mathematical modeling of the cooling system developed. It is expected that the mathematical modeling derived from this study will be used to estimate the use of the number of TEC module to be integrated with air conditioner unit where possible.

  17. Transformation of Chlorinated Benzenes and Toluenes by Ralstonia sp. Strain PS12 tecA (Tetrachlorobenzene Dioxygenase) and tecB (Chlorobenzene Dihydrodiol Dehydrogenase) Gene Products

    PubMed Central

    Pollmann, Katrin; Beil, Stefan; Pieper, Dietmar H.

    2001-01-01

    The tecB gene, located downstream of tecA and encoding tetrachlorobenzene dioxygenase, in Ralstonia sp. strain PS12 was cloned into Escherichia coli DH5α together with the tecA gene. The identity of the tecB gene product as a chlorobenzene dihydrodiol dehydrogenase was verified by transformation into the respective catechols of chlorobenzene, the three isomeric dichlorobenzenes, as well as 1,2,3- and 1,2,4-trichlorobenzenes, all of which are transformed by TecA into the respective dihydrodihydroxy derivatives. Di- and trichlorotoluenes were either subject to TecA-mediated dioxygenation (the major or sole reaction observed for the 1,2,4-substituted 2,4-, 2,5-, and 3,4-dichlorotoluenes), resulting in the formation of the dihydrodihydroxy derivatives, or to monooxygenation of the methyl substituent (the major or sole reaction observed for 2,3-, 2,6-, and 3,5-dichloro- and 2,4,5-trichlorotoluenes), resulting in formation of the respective benzyl alcohols. All of the chlorotoluenes subject to dioxygenation by TecA were transformed, without intermediate accumulation of dihydrodihydroxy derivatives, into the respective catechols by TecAB, indicating that dehydrogenation is no bottleneck for chlorobenzene or chlorotoluene degradation. However, only those chlorotoluenes subject to a predominant dioxygenation were growth substrates for PS12, confirming that monooxygenation is an unproductive pathway in PS12. PMID:11526005

  18. Latitudinal and Seasonal Investigations of Storm-Time TEC Variation

    NASA Astrophysics Data System (ADS)

    Adimula, I. A.; Oladipo, O. A.; Adebiyi, S. J.

    2016-07-01

    The ionosphere responds markedly and unpredictably to varying magnetospheric energy inputs caused by solar disturbances on the geospace. Knowledge of the impact of the space weather events on the ionosphere is important to assess the environmental effect on the operations of ground- and space-based technologies. Thus, global positioning system (GPS) measurements from the international GNSS service (IGS) database were used to investigate the ionospheric response to 56 geomagnetic storm events at six different latitudes comprising the northern and southern hemispheres in the Afro-European sector. Statistical distributions of total electron content (TEC) response show that during the main phase of the storms, enhancement of TEC is more pronounced in most of the seasons, regardless of the latitude and hemisphere. However, a strong seasonal dependence appears in the TEC response during the recovery phase. Depletion of TEC is majorly observed at the high latitude stations, and its appearance at lower latitudes is seasonally dependent. In summer hemisphere, the depletion of TEC is more pronounced in nearly all the latitudinal bands. In winter hemisphere, enhancement as well as depletion of TEC is observed over the high latitude, while enhancement is majorly observed over the mid and low latitudes. In equinoxes, the storm-time TEC distribution shows a fairly consistent characteristic with the summer distribution, particularly in the northern hemisphere.

  19. Observing Traveling Ionospheric Disturbances Caused by Tsunamis Using GPS TEC Measurements

    NASA Technical Reports Server (NTRS)

    Galvan, David A.; Komjathy, Attila; Hickey, Michael; Foster, James; Mannucci, Anthony J.

    2010-01-01

    Ground-based Global Positioning System (GPS) measurements of ionospheric Total Electron Content (TEC) show variations consistent with atmospheric internal gravity waves caused by ocean tsunamis following two recent seismic events: the American Samoa earthquake of September 29, 2009, and the Chile earthquake of February 27, 2010. Fluctuations in TEC correlated in time, space, and wave properties with these tsunamis were observed in TEC estimates processed using JPL's Global Ionospheric Mapping Software. These TEC estimates were band-pass filtered to remove ionospheric TEC variations with wavelengths and periods outside the typical range of internal gravity waves caused by tsunamis. Observable variations in TEC appear correlated with the tsunamis in certain locations, but not in others. Where variations are observed, the typical amplitude tends to be on the order of 1% of the background TEC value. Variations with amplitudes 0.1 - 0.2 TECU are observable with periods and timing affiliated with the tsunami. These observations are compared to estimates of expected tsunami-driven TEC variations produced by Embry Riddle Aeronautical University's Spectral Full Wave Model, an atmosphere-ionosphere coupling model, and found to be in good agreement in some locations, though there are cases when the model predicts an observable tsunami-driven signature and none is observed. These TEC variations are not always seen when a tsunami is present, but in these two events the regions where a strong ocean tsunami was observed did coincide with clear TEC observations, while a lack of clear TEC observations coincided with smaller tsunami amplitudes. There exists the potential to apply these detection techniques to real-time GPS TEC data, providing estimates of tsunami speed and amplitude that may be useful for early warning systems.

  20. Long-term trends in the total electron content (TEC)

    NASA Astrophysics Data System (ADS)

    Laštovička, Jan

    2017-04-01

    The long-term trends in the total electron content (TEC) have very little been studied. Lean et al. (2011; J. Geophys. Res., 116, A00H04, doi:10.1029/2010JA016378) studied trends in TEC globally based on JPL maps for 1995-2010. However, their trends appear to be too positive, which is not plausible taking into account the trends in other ionospheric parameters. Therefore they prefer the less positive trends calculated under the assumption of the same level of solar activity in solar cycle minima 22/23 and 23/24. However, as it is now clear, this is not a correct assumption. Lastovicka (2013; J. Geophys. Res. Space Phys., 118, 3831-3835, doi:10.1002/jgra.50261) selected a region around Florence, Italy, as a region with available historical TEC data based on Faraday rotation measurements and remarkably larger than average trends in TEC by Lean et al. (2011). Historical data from Florence provide no trend in TEC. However, foF2 from Juliusruh provide slight negative trends for 1976-1996 but no trends for 1995-2010. Thus the question of reality of trends by Lean et al. (2011) remained open. Here we use TEC from GIM and JPL data for two European regions with high Lean's trends, regions around Florence and around Prague, using 10-14 LT medians, 1998-2015, yearly average values. A classical approach is applied. First a model of solar activity dependence of TEC is constructed separately for each region from all data. Then model data are subtracted from experimental data and analysis is made with residuals. This analysis shows that early data (1998-2001) are by several TECU lower than they should be according to solar activity, the year 2002 is intermediate and in 2003-2015 the data fit well a weak or rather no trend of TEC. The change in TEC data does not seem to be jump-like, it lasted at least a year, if not longer. Thus the positive TEC trends reported by Lean et al. (2011) appear to be affected by data problem; real trends are evidently less positive if any.

  1. Assessment of Modeling Capability for Reproducing Storm Impacts on TEC

    NASA Astrophysics Data System (ADS)

    Shim, J. S.; Kuznetsova, M. M.; Rastaetter, L.; Bilitza, D.; Codrescu, M.; Coster, A. J.; Emery, B. A.; Foerster, M.; Foster, B.; Fuller-Rowell, T. J.; Huba, J. D.; Goncharenko, L. P.; Mannucci, A. J.; Namgaladze, A. A.; Pi, X.; Prokhorov, B. E.; Ridley, A. J.; Scherliess, L.; Schunk, R. W.; Sojka, J. J.; Zhu, L.

    2014-12-01

    During geomagnetic storm, the energy transfer from solar wind to magnetosphere-ionosphere system adversely affects the communication and navigation systems. Quantifying storm impacts on TEC (Total Electron Content) and assessment of modeling capability of reproducing storm impacts on TEC are of importance to specifying and forecasting space weather. In order to quantify storm impacts on TEC, we considered several parameters: TEC changes compared to quiet time (the day before storm), TEC difference between 24-hour intervals, and maximum increase/decrease during the storm. We investigated the spatial and temporal variations of the parameters during the 2006 AGU storm event (14-15 Dec. 2006) using ground-based GPS TEC measurements in the selected 5 degree eight longitude sectors. The latitudinal variations were also studied in two longitude sectors among the eight sectors where data coverage is relatively better. We obtained modeled TEC from various ionosphere/thermosphere (IT) models. The parameters from the models were compared with each other and with the observed values. We quantified performance of the models in reproducing the TEC variations during the storm using skill scores. This study has been supported by the Community Coordinated Modeling Center (CCMC) at the Goddard Space Flight Center. Model outputs and observational data used for the study will be permanently posted at the CCMC website (http://ccmc.gsfc.nasa.gov) for the space science communities to use.

  2. A dual-stage sodium thermal electrochemical converter (Na-TEC)

    NASA Astrophysics Data System (ADS)

    Limia, Alexander; Ha, Jong Min; Kottke, Peter; Gunawan, Andrey; Fedorov, Andrei G.; Lee, Seung Woo; Yee, Shannon K.

    2017-12-01

    The sodium thermal electrochemical converter (Na-TEC) is a heat engine that generates electricity through the isothermal expansion of sodium ions. The Na-TEC is a closed system that can theoretically achieve conversion efficiencies above 45% when operating between thermal reservoirs at 1150 K and 550 K. However, thermal designs have confined previous single-stage devices to thermal efficiencies below 20%. To mitigate some of these limitations, we consider dividing the isothermal expansion into two stages; one at the evaporator temperature (1150 K) and another at an intermediate temperature (650 K-1050 K). This dual-stage Na-TEC takes advantage of regeneration and reheating, and could be amenable to better thermal management. Herein, we demonstrate how the dual-stage device can improve the efficiency by up to 8% points over the best performing single-stage device. We also establish an application regime map for the single- and dual-stage Na-TEC in terms of the power density and the total thermal parasitic loss. Generally, a single-stage Na-TEC should be used for applications requiring high power densities, whereas a dual-stage Na-TEC should be used for applications requiring high efficiency.

  3. CFD Extraction Tool for TecPlot From DPLR Solutions

    NASA Technical Reports Server (NTRS)

    Norman, David

    2013-01-01

    This invention is a TecPlot macro of a computer program in the TecPlot programming language that processes data from DPLR solutions in TecPlot format. DPLR (Data-Parallel Line Relaxation) is a NASA computational fluid dynamics (CFD) code, and TecPlot is a commercial CFD post-processing tool. The Tec- Plot data is in SI units (same as DPLR output). The invention converts the SI units into British units. The macro modifies the TecPlot data with unit conversions, and adds some extra calculations. After unit conversions, the macro cuts a slice, and adds vectors on the current plot for output format. The macro can also process surface solutions. Existing solutions use manual conversion and superposition. The conversion is complicated because it must be applied to a range of inter-related scalars and vectors to describe a 2D or 3D flow field. It processes the CFD solution to create superposition/comparison of scalars and vectors. The existing manual solution is cumbersome, open to errors, slow, and cannot be inserted into an automated process. This invention is quick and easy to use, and can be inserted into an automated data-processing algorithm.

  4. TEC protein tyrosine kinase is involved in the Erk signaling pathway induced by HGF

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

    Li, Feifei; Jiang, Yinan; Zheng, Qiping

    Research highlights: {yields} TEC is rapidly tyrosine-phosphorylated and activated by HGF-stimulation in vivo or after partial hepatectomy in mice. {yields} TEC enhances the activity of Elk and serum response element (SRE) in HGF signaling pathway in hepatocyte. {yields} TEC promotes hepatocyte proliferation through the Erk-MAPK pathway. -- Abstract: Background/aims: TEC, a member of the TEC family of non-receptor type protein tyrosine kinases, has recently been suggested to play a role in hepatocyte proliferation and liver regeneration. This study aims to investigate the putative mechanisms of TEC kinase regulation of hepatocyte differentiation, i.e. to explore which signaling pathway TEC is involvedmore » in, and how TEC is activated in hepatocyte after hepatectomy and hepatocyte growth factor (HGF) stimulation. Methods: We performed immunoprecipitation (IP) and immunoblotting (IB) to examine TEC tyrosine phosphorylation after partial hepatectomy in mice and HGF stimulation in WB F-344 hepatic cells. The TEC kinase activity was determined by in vitro kinase assay. Reporter gene assay, antisense oligonucleotide and TEC dominant negative mutant (TEC{sup KM}) were used to examine the possible signaling pathways in which TEC is involved. The cell proliferation rate was evaluated by {sup 3}H-TdR incorporation. Results: TEC phosphorylation and kinase activity were increased in 1 h after hepatectomy or HGF treatment. TEC enhanced the activity of Elk and serum response element (SRE). Inhibition of MEK1 suppressed TEC phosphorylation. Blocking TEC activity dramatically decreased the activation of Erk. Reduced TEC kinase activity also suppressed the proliferation of WB F-344 cells. These results suggest TEC is involved in the Ras-MAPK pathway and acts between MEK1 and Erk. Conclusions: TEC promotes hepatocyte proliferation and regeneration and is involved in HGF-induced Erk signaling pathway.« less

  5. Operation and Maintenance Manual, TECS 18.

    DTIC Science & Technology

    1978-11-01

    width modulated variable output voltage and frequency using a three-phase transistor bridge circuit . Reduced power line electromagnetic interference...Description 3-1 Section II. Circuit Fundamentals 3-1 Section III. System Description 3-2 CHAPTER 4. Protection and Maintenance 4-1 Section I. Internal...Number I-la TECS 18 Electronic Module Location-Evaporator Side 1-3 1-lb TECS 18 Electronic Module Location-Condenser Side 1-4 1-2 Remote Control Panel 1-5

  6. CoLiTec software - detection of the near-zero apparent motion

    NASA Astrophysics Data System (ADS)

    Khlamov, Sergii V.; Savanevych, Vadym E.; Briukhovetskyi, Olexandr B.; Pohorelov, Artem V.

    2017-06-01

    In this article we described CoLiTec software for full automated frames processing. CoLiTec software allows processing the Big Data of observation results as well as processing of data that is continuously formed during observation. The scope of solving tasks includes frames brightness equalization, moving objects detection, astrometry, photometry, etc. Along with the high efficiency of Big Data processing CoLiTec software also ensures high accuracy of data measurements. A comparative analysis of the functional characteristics and positional accuracy was performed between CoLiTec and Astrometrica software. The benefits of CoLiTec used with wide field and low quality frames were observed. The efficiency of the CoLiTec software was proved by about 700.000 observations and over 1.500 preliminary discoveries.

  7. Space Weather Activities of IONOLAB Group: TEC Mapping

    NASA Astrophysics Data System (ADS)

    Arikan, F.; Yilmaz, A.; Arikan, O.; Sayin, I.; Gurun, M.; Akdogan, K. E.; Yildirim, S. A.

    2009-04-01

    Being a key player in Space Weather, ionospheric variability affects the performance of both communication and navigation systems. To improve the performance of these systems, ionosphere has to be monitored. Total Electron Content (TEC), line integral of the electron density along a ray path, is an important parameter to investigate the ionospheric variability. A cost-effective way of obtaining TEC is by using dual-frequency GPS receivers. Since these measurements are sparse in space, accurate and robust interpolation techniques are needed to interpolate (or map) the TEC distribution for a given region in space. However, the TEC data derived from GPS measurements contain measurement noise, model and computational errors. Thus, it is necessary to analyze the interpolation performance of the techniques on synthetic data sets that can represent various ionospheric states. By this way, interpolation performance of the techniques can be compared over many parameters that can be controlled to represent the desired ionospheric states. In this study, Multiquadrics, Inverse Distance Weighting (IDW), Cubic Splines, Ordinary and Universal Kriging, Random Field Priors (RFP), Multi-Layer Perceptron Neural Network (MLP-NN), and Radial Basis Function Neural Network (RBF-NN) are employed as the spatial interpolation algorithms. These mapping techniques are initially tried on synthetic TEC surfaces for parameter and coefficient optimization and determination of error bounds. Interpolation performance of these methods are compared on synthetic TEC surfaces over the parameters of sampling pattern, number of samples, the variability of the surface and the trend type in the TEC surfaces. By examining the performance of the interpolation methods, it is observed that both Kriging, RFP and NN have important advantages and possible disadvantages depending on the given constraints. It is also observed that the determining parameter in the error performance is the trend in the Ionosphere

  8. Short Term Single Station GNSS TEC Prediction Using Radial Basis Function Neural Network

    NASA Astrophysics Data System (ADS)

    Muslim, Buldan; Husin, Asnawi; Efendy, Joni

    2018-04-01

    TEC prediction models for 24 hours ahead have been developed from JOG2 GPS TEC data during 2016. Eleven month of TEC data were used as a training model of the radial basis function neural network (RBFNN) and 1 month of last data (December 2016) is used for the RBFNN model testing. The RBFNN inputs are the previous 24 hour TEC data and the minimum of Dst index during the previous 24 hours. Outputs of the model are 24 ahead TEC prediction. Comparison of model prediction show that the RBFNN model is able to predict the next 24 hours TEC is more accurate than the TEC GIM model.

  9. The Response of Mid-Latitude Ionospheric TEC to Geomagnetic Storms and Solar Flares

    NASA Astrophysics Data System (ADS)

    Huang, Z.; Roussel-Dupre, R.

    2004-12-01

    The effects of geomagnetic storms and solar flares on the ionosphere are manifested as large magnitude sudden fluctuations in the Total Electron Content (TEC). In this study, the broadband VHF signal (30-100MHz) data from the Los Alamos Portable Pulser (LAPP) received by the FORTE (Fast Onboard Recording of Transient Events) satellite during the period of 1997-2002 are used to investigate the mean TEC variation response to geomagnetic storm. A total of 14 geomagnetic storms are selected where FORTE-LAPP data are available to derive average TECs during extended storm-time and non-storm time for a given storm. The variations in the ionospheric TECs at Los Alamos, New Mexico are investigated for the 14 selected geomagnetic storms. In most cases (12 out of 14), we see overall enhancements in TEC as a result of geomagnetic storm impact at Los Alamos. The relative enhancements in TEC at Los Alamos due to a geomagnetic storm can reach as high as 3-fold of the normal TEC values. The overall absolute enhancements in TEC at Los Alamos are up to about 30 TECU. The magnitude of TEC enhancements is diversified over all storm categories without a clean-cut relationship between the storm intensity and the TEC enhancement. The mean TEC variation response to geomagnetic storm can be complicated when several consecutive storms occurred in a row and a net TEC reduction may be seen. Data of continuous GPS TEC measurements are collected at a 1-minute time resolution during July 2004 when 5 X-class solar flares occurred from two Allen Osborne Associates ICS-4000Z GPS receivers mounted at the Physics Building at Los Alamos National Laboratory. In detecting effects of solar flares on the ionospheric TEC, we apply appropriate filtering to remove the linear trend of TEC and a coherent processing of TEC variations simultaneously for all the visible GPS satellites in a given time interval. The responses of ionospheric TEC at minute time scale to these powerful impulsive solar flares are

  10. Quantitative Evaluation of Ionosphere Models for Reproducing Regional TEC During Geomagnetic Storms

    NASA Astrophysics Data System (ADS)

    Shim, J. S.; Kuznetsova, M.; Rastaetter, L.; Bilitza, D.; Codrescu, M.; Coster, A. J.; Emery, B.; Foster, B.; Fuller-Rowell, T. J.; Goncharenko, L. P.; Huba, J.; Mitchell, C. N.; Ridley, A. J.; Fedrizzi, M.; Scherliess, L.; Schunk, R. W.; Sojka, J. J.; Zhu, L.

    2015-12-01

    TEC (Total Electron Content) is one of the key parameters in description of the ionospheric variability that has influence on the accuracy of navigation and communication systems. To assess current TEC modeling capability of ionospheric models during geomagnetic storms and to establish a baseline against which future improvement can be compared, we quantified the ionospheric models' performance by comparing modeled vertical TEC values with ground-based GPS TEC measurements and Multi-Instrument Data Analysis System (MIDAS) TEC. The comparison focused on North America and Europe sectors during selected two storm events: 2006 AGU storm (14-15 Dec. 2006) and 2013 March storm (17-19 Mar. 2013). The ionospheric models used for this study range from empirical to physics-based, and physics-based data assimilation models. We investigated spatial and temporal variations of TEC during the storms. In addition, we considered several parameters to quantify storm impacts on TEC: TEC changes compared to quiet time, rate of TEC change, and maximum increase/decrease during the storms. In this presentation, we focus on preliminary results of the comparison of the models performance in reproducing the storm-time TEC variations using the parameters and skill scores. This study has been supported by the Community Coordinated Modeling Center (CCMC) at the Goddard Space Flight Center. Model outputs and observational data used for the study will be permanently posted at the CCMC website (http://ccmc.gsfc.nasa.gov) for the space science communities to use.

  11. 78 FR 64207 - Application To Export Electric Energy; TEC Energy Inc.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-28

    ... DEPARTMENT OF ENERGY [OE Docket No. EA-388] Application To Export Electric Energy; TEC Energy Inc. AGENCY: Office of Electricity Delivery and Energy Reliability, DOE. ACTION: Notice of Application. SUMMARY: TEC Energy Inc. (TEC) has applied for authority to transmit electric energy from the United...

  12. TEC variability near northern EIA crest and comparison with IRI model

    NASA Astrophysics Data System (ADS)

    Aggarwal, Malini

    2011-10-01

    Monthly median values of hourly total electron content (TEC) is obtained with GPS at a station near northern anomaly crest, Rajkot (geog. 22.29°N, 70.74°E; geomag. 14.21°N, 144.9°E) to study the variability of low latitude ionospheric behavior during low solar activity period (April 2005 to March 2006). The TEC exhibit characteristic features like day-to-day variability, semiannual anomaly and noon bite out. The observed TEC is compared with latest International Reference Ionosphere (IRI) - 2007 model using options of topside electron density, NeQuick, IRI01-corr and IRI-2001 by using both URSI and CCIR coefficients. A good agreement of observed and predicted TEC is found during the daytime with underestimation at other times. The predicted TEC by NeQuick and IRI01-corr is closer to the observed TEC during the daytime whereas during nighttime and morning hours, IRI-2001 shows lesser discrepancy in all seasons by both URSI and CCIR coefficients.

  13. StarTEC: A Technology Project in Education Reform.

    ERIC Educational Resources Information Center

    Hawley, Helen; Benavides, Otto; Duffy, Sharon; Georgi, David; Guay, Diane; Redmond, Pamela; Richmond, James

    StarTEC (Staff, Teacher, and Restructured Technology Education Consortium) was a 3-year technology catalyst program funded by the U.S. Department of Education, and continued for a third year to complete its activities. The goal of StarTEC was to ensure that all teachers prepared by partners in the Consortium would meet the new California standard…

  14. Comparison of Two IRI plasmasphere Extensions with GPS-TEC Observations

    NASA Technical Reports Server (NTRS)

    Gulyaeva, T. L.; Gallagher, Dennis L.

    2006-01-01

    Comparisons of two model results with Global Positioning System GPS-TEC measurements have been carried out for different latitudinal, solar activity, magnetic activity, diurnal and seasonal conditions. The models evaluated are the Global Core Plasma Model (GCPM-2000) and the IRI extension with Russian plasmasphere model (IRI*).Data of 23 observatories providing GPS-TEC and ionosonde data have been used. It is shown that IRI* plasmasphere electron density is greater than GCPM results by an order of magnitude at 6370 km altitude (one Earth's radius) with this excess growing to 2-3 orders of magnitude towards the GPS satellite altitude of 20000 km. Another source of model and GPS-TEC differences is a way of selection of the F2 layer peak parameters driving the models either with ITU-R (former CCIR) maps or ionosonde observations. Plasmasphere amendment to IRI improves accuracy of TEC model predictions because the plasmasphere contribution to the total TEC varies from 10% by daytime under quiet magnetic conditions to more than 50% by night under stormy conditions.

  15. Derivation of GPS TEC and receiver bias for Langkawi station in Malaysia

    NASA Astrophysics Data System (ADS)

    Teh, W. L.; Chen, W. S.; Abdullah, M.

    2017-05-01

    This paper presents the polynomial-type TEC model to derive total electron content (TEC) and receiver bias for Langkawi (LGKW) station in Malaysia at geographic latitude of 6.32° and longitude of 99.85°. The model uses a polynomial function of coordinates of the ionospheric piercing point to describe the TEC distribution in space. In the model, six polynomial coefficients and a receiver bias are unknown which can be solved by the least squares method. A reasonable agreement is achieved for the derivation of TEC and receiver bias for IENG station in Italy, as compared with that derived by the IGS analysis center, CODE. We process one year of LGKW data in 2010 and show the monthly receiver bias and the seasonal TEC variation. The monthly receiver bias varies between -48 and -24 TECu (1016 electrons/m2), with the mean value at -37 TECu. Large variations happen in the monthly receiver biases due to the low data coverage of high satellite elevation angle (60° < α ≤ 90°). Post-processing TEC approach is implemented which can resolve the wavy pattern of the monthly TEC baseline resulted from the large variation of the receiver bias. The seasonal TEC variation at LGKW exhibits a semi-annual variation, where the peak occurs during equinoctial months, and the trough during summer and winter months.

  16. Ionospheric earthquake effects detection based on Total Electron Content (TEC) GPS Correlation

    NASA Astrophysics Data System (ADS)

    Sunardi, Bambang; Muslim, Buldan; Eka Sakya, Andi; Rohadi, Supriyanto; Sulastri; Murjaya, Jaya

    2018-03-01

    Advances in science and technology showed that ground-based GPS receiver was able to detect ionospheric Total Electron Content (TEC) disturbances caused by various natural phenomena such as earthquakes. One study of Tohoku (Japan) earthquake, March 11, 2011, magnitude M 9.0 showed TEC fluctuations observed from GPS observation network spread around the disaster area. This paper discussed the ionospheric earthquake effects detection using TEC GPS data. The case studies taken were Kebumen earthquake, January 25, 2014, magnitude M 6.2, Sumba earthquake, February 12, 2016, M 6.2 and Halmahera earthquake, February 17, 2016, M 6.1. TEC-GIM (Global Ionosphere Map) correlation methods for 31 days were used to monitor TEC anomaly in ionosphere. To ensure the geomagnetic disturbances due to solar activity, we also compare with Dst index in the same time window. The results showed anomalous ratio of correlation coefficient deviation to its standard deviation upon occurrences of Kebumen and Sumba earthquake, but not detected a similar anomaly for the Halmahera earthquake. It was needed a continous monitoring of TEC GPS data to detect the earthquake effects in ionosphere. This study giving hope in strengthening the earthquake effect early warning system using TEC GPS data. The method development of continuous TEC GPS observation derived from GPS observation network that already exists in Indonesia is needed to support earthquake effects early warning systems.

  17. Long-Term Prediction of the Arctic Ionospheric TEC Based on Time-Varying Periodograms

    PubMed Central

    Liu, Jingbin; Chen, Ruizhi; Wang, Zemin; An, Jiachun; Hyyppä, Juha

    2014-01-01

    Knowledge of the polar ionospheric total electron content (TEC) and its future variations is of scientific and engineering relevance. In this study, a new method is developed to predict Arctic mean TEC on the scale of a solar cycle using previous data covering 14 years. The Arctic TEC is derived from global positioning system measurements using the spherical cap harmonic analysis mapping method. The study indicates that the variability of the Arctic TEC results in highly time-varying periodograms, which are utilized for prediction in the proposed method. The TEC time series is divided into two components of periodic oscillations and the average TEC. The newly developed method of TEC prediction is based on an extrapolation method that requires no input of physical observations of the time interval of prediction, and it is performed in both temporally backward and forward directions by summing the extrapolation of the two components. The backward prediction indicates that the Arctic TEC variability includes a 9 years period for the study duration, in addition to the well-established periods. The long-term prediction has an uncertainty of 4.8–5.6 TECU for different period sets. PMID:25369066

  18. Te/C nanocomposites for Li-Te Secondary Batteries

    NASA Astrophysics Data System (ADS)

    Seo, Jeong-Uk; Seong, Gun-Kyu; Park, Cheol-Min

    2015-01-01

    New battery systems having high energy density are actively being researched in order to satisfy the rapidly developing market for longer-lasting mobile electronics and hybrid electric vehicles. Here, we report a new Li-Te secondary battery system with a redox potential of ~1.7 V (vs. Li+/Li) adapted on a Li metal anode and an advanced Te/C nanocomposite cathode. Using a simple concept of transforming TeO2 into nanocrystalline Te by mechanical reduction, we designed an advanced, mechanically reduced Te/C nanocomposite electrode material with high energy density (initial discharge/charge: 1088/740 mA h cm-3), excellent cyclability (ca. 705 mA h cm-3 over 100 cycles), and fast rate capability (ca. 550 mA h cm-3 at 5C rate). The mechanically reduced Te/C nanocomposite electrodes were found to be suitable for use as either the cathode in Li-Te secondary batteries or a high-potential anode in rechargeable Li-ion batteries. We firmly believe that the mechanically reduced Te/C nanocomposite constitutes a breakthrough for the realization and mass production of excellent energy storage systems.

  19. Detection of Seismic Precursors Using Distance Metrics Between GPS-TEC and IRI-Plas

    NASA Astrophysics Data System (ADS)

    Necat Deviren, M.; Gulyaeva, Tamara; Sezen, Umut; Arikan, Feza; Arikan, Orhan

    Ionosphere is an important layer of atmosphere that varies under solar, geomagnetic, gravitational and seismic activities. Total Electron Content (TEC) is one of the main observables of ionosphere. International Reference Ionosphere Extended to Plasmasphere (IRI-Plas) is accepted by International Organization for Standardization (ISO) as the standard climatic model. IRI-Plas provides TEC up to GPS satellite height. TEC can be estimated using Global Positioning System (GPS) Networks. In this study, TEC is computed using both IRI-Plas and Turkish National Permanent GPS Network as IONOLAB-TEC. In order to detect seismic precursors, three different distance metrics, namely Symmetric Kullback-Liebler Distance (SKLD), Cross-Correlation Coefficient (CC), and L2-Norm (L2N), are implemented between IONOLAB-TEC and IRI-Plas-TEC values. SKLD is also computed between IONOLAB-TEC Maps and IRI-Plas-TEC Maps over Turkey. Between May 2009 and September 2012, it is observed that SKLD metric indicates a disturbance within the period prior to 10 days of earthquake day. The disturbance in SKLD increases for the range of stations in the neighborhood of the epicenter. For strong earthquakes all of the three distance metrics indicate a disturbance before the earthquake, yet SKLD behaves as a more sensitive precursor for earthquakes larger than magnitude 4. This study is supported by the joint grant of TUBITAK 112E568 and RFBR 13-02-91370-CT_a.

  20. Comparison of GPS-derived TEC with IRI-2012 and IRI-2007 TEC predictions at Surat, a location around the EIA crest in the Indian sector, during the ascending phase of solar cycle 24

    NASA Astrophysics Data System (ADS)

    Patel, N. C.; Karia, S. P.; Pathak, K. N.

    2017-07-01

    This paper presents a comparison of GPS-derived TEC with IRI-2012 and IRI-2007 TEC Predictions at Surat (21.16°N Geographic latitude, 72.78°E Geographic longitude, 12.90°N Geomagnetic latitude) a location around the Equatorial Ionisation Anomaly (EIA) crest in the Indian sector, during the Ascending Phase of Solar Cycle 24, for a period of three years (January 2010-December 2012). In this comparison, plasmaspheric electron content (PEC) contribution to the GPS-TEC has been removed. It is observed that percentage PEC contribution to the GPS-TEC varies from about ∼15% (at the noon local time) to about ∼30% (at the morning local time). From the monthly comparison of GPS-TEC with IRI-TEC, it is observed that, TEC predicted by both the models overestimates in June-2012 and underestimates TEC in November-2011, December-2011 and March-2011. For all other months IRI estimates the TEC well. From the seasonal comparison, it is observed that the peak time appears ∼1-h later than the actual peak time in Winter 2010, Summer 2011, and Equinox 2010 and 2012 (the result suggest that it may be due to discrepancies/disagreement of both the versions of the IRI model in estimating the peak density as well as the thickness and shape parameters of the electron density profiles). For the Summer season, the IRI-TEC estimates the TEC well for all the years. Further, the seasonal variation of the GPS-TEC for all the three years matches well with IRI-2012 model compared to IRI-2007 model. Also, the mean annual TEC is predicted well by both the versions of the IRI model.

  1. Distinct and Overlapping Functions of TEC Kinase and BTK in B Cell Receptor Signaling.

    PubMed

    de Bruijn, Marjolein J W; Rip, Jasper; van der Ploeg, Esmee K; van Greuningen, Lars W; Ta, Van T B; Kil, Laurens P; Langerak, Anton W; Rimmelzwaan, Guus F; Ellmeier, Wilfried; Hendriks, Rudi W; Corneth, Odilia B J

    2017-04-15

    The Tec tyrosine kinase is expressed in many cell types, including hematopoietic cells, and is a member of the Tec kinase family that also includes Btk. Although the role of Btk in B cells has been extensively studied, the role of Tec kinase in B cells remains largely unclear. It was previously shown that Tec kinase has the ability to partly compensate for loss of Btk activity in B cell differentiation, although the underlying mechanism is unknown. In this study, we confirm that Tec kinase is not essential for normal B cell development when Btk is present, but we also found that Tec-deficient mature B cells showed increased activation, proliferation, and survival upon BCR stimulation, even in the presence of Btk. Whereas Tec deficiency did not affect phosphorylation of phospholipase Cγ or Ca 2+ influx, it was associated with significantly increased activation of the intracellular Akt/S6 kinase signaling pathway upon BCR and CD40 stimulation. The increased S6 kinase phosphorylation in Tec-deficient B cells was dependent on Btk kinase activity, as ibrutinib treatment restored pS6 to wild-type levels, although Btk protein and phosphorylation levels were comparable to controls. In Tec-deficient mice in vivo, B cell responses to model Ags and humoral immunity upon influenza infection were enhanced. Moreover, aged mice lacking Tec kinase developed a mild autoimmune phenotype. Taken together, these data indicate that in mature B cells, Tec and Btk may compete for activation of the Akt signaling pathway, whereby the activating capacity of Btk is limited by the presence of Tec kinase. Copyright © 2017 by The American Association of Immunologists, Inc.

  2. High-resolution station-based diurnal ionospheric total electron content (TEC) from dual-frequency GPS observations

    NASA Astrophysics Data System (ADS)

    ćepni, Murat S.; Potts, Laramie V.; Miima, John B.

    2013-09-01

    electron content (TEC) estimates derived from Global Navigation Satellite System (GNSS) signal delays provide a rich source of information about the Earth's ionosphere. Networks of Global Positioning System (GPS) receivers data can be used to represent the ionosphere by a Global Ionospheric Map (GIM). Data input for GIMs is dual-frequency GNSS-only or a mixture of GNSS and altimetry observations. Parameterization of GNSS-only GIMs approaches the ionosphere as a single-layer model (SLM) to determine GPS TEC models over a region. Limitations in GNSS-only GIM TEC are due largely to the nonhomogenous global distribution of GPS tracking stations with large data gaps over the oceans. The utility of slant GPS ionospheric-induced path delays for high temporal resolution from a single-station data rate offers better representation of TEC over a small region. A station-based vertical TEC (TECV) approach modifies the traditional single-layer model (SLM) GPS TEC method by introducing a zenith angle weighting (ZAW) filter to capture signal delays from mostly near-zenith satellite passes. Comparison with GIMs shows the station-dependent TEC (SD-TEC) model exhibits robust performance under variable space weather conditions. The SD-TEC model was applied to investigate ionospheric TEC variability during the geomagnetic storm event of 9 March 2012 at midlatitude station NJJJ located in New Jersey, USA. The high temporal resolution TEC results suggest TEC production and loss rate differences before, during, and after the storm.

  3. GIM-TEC adaptive ionospheric weather assessment and forecast system

    NASA Astrophysics Data System (ADS)

    Gulyaeva, T. L.; Arikan, F.; Hernandez-Pajares, M.; Stanislawska, I.

    2013-09-01

    The Ionospheric Weather Assessment and Forecast (IWAF) system is a computer software package designed to assess and predict the world-wide representation of 3-D electron density profiles from the Global Ionospheric Maps of Total Electron Content (GIM-TEC). The unique system products include daily-hourly numerical global maps of the F2 layer critical frequency (foF2) and the peak height (hmF2) generated with the International Reference Ionosphere extended to the plasmasphere, IRI-Plas, upgraded by importing the daily-hourly GIM-TEC as a new model driving parameter. Since GIM-TEC maps are provided with 1- or 2-days latency, the global maps forecast for 1 day and 2 days ahead are derived using an harmonic analysis applied to the temporal changes of TEC, foF2 and hmF2 at 5112 grid points of a map encapsulated in IONEX format (-87.5°:2.5°:87.5°N in latitude, -180°:5°:180°E in longitude). The system provides online the ionospheric disturbance warnings in the global W-index map establishing categories of the ionospheric weather from the quiet state (W=±1) to intense storm (W=±4) according to the thresholds set for instant TEC perturbations regarding quiet reference median for the preceding 7 days. The accuracy of IWAF system predictions of TEC, foF2 and hmF2 maps is superior to the standard persistence model with prediction equal to the most recent ‘true’ map. The paper presents outcomes of the new service expressed by the global ionospheric foF2, hmF2 and W-index maps demonstrating the process of origin and propagation of positive and negative ionosphere disturbances in space and time and their forecast under different scenarios.

  4. Regional And Seasonal Aspects Of Within-The-Hour Tec Statistics

    NASA Astrophysics Data System (ADS)

    Koroglu, Ozan; Arikan, Feza; Koroglu, Meltem

    2015-04-01

    Ionosphere is one of the atmosphere layers which has a plasma structure. Several mechanisms originating from both space and earth itself governs this plasma layer such as solar radiation and geomagnetic effects. Ionosphere plays important role for HF and satellite communication, and space based positioning systems. Therefore, the determination of statistical behavior of ionosphere has utmost importance. The variability of the ionosphere has complex spatio-temporal characteristics, which depends on solar, geomagnetic, gravitational and seismic activities. Total Electron Content (TEC) is one of the major observables for investigating and determining this variability. In this study, spatio-temporal within-the-hour statistical behavior of TEC is determined for Turkey, which is located in mid-latitude, using the TEC estimates from Turkish National Permanent GPS Network (TNPGN)-Active between the years 2009 and 2012. TEC estimates are obtained as IONOLAB-TEC which is developed by IONOLAB group (www.ionolab.org) from Hacettepe University. IONOLAB-TEC for each station in TNPGN-Active is organized in a database and grouped with respect to years, ionospheric seasons, hours and regions 2 degree by 3 degree, in latitude and longitude, respectively. The data sets are used to calculate within-the-hour parametric Probability Density Functions (PDF). For every year, every region and every hour, a representative PDF is determined. It is observed that TEC values have a strong hourly, seasonal and positional dependence on east-west direction, and the growing trend shifts according to sunrise and sunset times. It is observed that the data are distributed predominantly as Lognormal and Weibull. The averages and standard deviations of the chosen distributions follow the trends in 24 hour diurnal and 11 year solar cycle periods. The regional and seasonal behavior of PDFs are investigated using a representative GPS station within each region. Within-the-hour PDF estimates are grouped into

  5. Joint Analysis of the Full AzTEC Sub-Millimeter Galaxy Data Set

    NASA Astrophysics Data System (ADS)

    Wilson, Grant; Ade, P.; Aretxaga, I.; Austermann, J.; Bock, J.; Hughes, D.; Kang, Y.; Kim, S.; Lowenthal, J.; Mauskopf, P.; Perera, T.; Scott, K.; Yun, M.

    2006-12-01

    Using the new AzTEC millimeter-wave camera on the James Clerk Maxwell Telescope (JCMT) in winter 2005/06, we conducted several surveys of the submm galaxy (SMG) population. The AzTEC 1.1 millimeter surveys include both blank-fields (no significant bias or foreground contamination) and regions of known over-densities, and are both large (100-1000 sq. arcmin.) and sensitive ( 1 mJy rms). The unique power of the AzTEC data set lies not only in the size and depth of the individual fields, but in the combined surveyed area that totals over 1 square degree. Hundreds of new sub-millimeter sources have been detected. A joint analysis of all AzTEC surveys will provide important new constraints on many characteristics of the SMG population, including number counts, clustering, and variance. In particular, the large area of the full AzTEC data set provides the first significant measurement of the brightest and most rare of the SMG population. Herein we present the initial combined results and explore the future potential of a complete joint analysis of the full AzTEC SMG data set.

  6. Short-Term TEC Perturbations Associated With Planetary Waves Occurrence in the Ionosphere

    NASA Astrophysics Data System (ADS)

    Shagimuratov, I. I.; Karpov, I.; Krankowski, A.

    2008-12-01

    Analysis of TEC response to storm showed short-term perturbations which were observed after initial phase of geomagnetic storms. The perturbations demonstrated very well expressed latitudinal structure and were recognized on diurnal variations as surges of TEC enhancement of TEC. Ordinary such storm-time positive effect was associated with TAD. Duration of the perturbations was about 2-4 hours and their amplitude increased toward low latitudes. Such TEC perturbations have the longitudinal dependence. It is important that time location of surges have week dependence on latitude. The observed structure appeared to arrive from high latitudes, but at middle latitudes it was represented as a standing wave. It is assumed that such TEC perturbations can be produced due to superposition of the eastward and westward propagating planetary Poincare waves. The periods of these waves are usually several hours. Poincare waves can be excited at the atmosphere in storm time. At middle latitudes their superposition is as standing wave that forms observing TEC perturbations. In the report, the possibilities of application Poincare waves to the ionosphere dynamics studies are discussed and an explanation of the observed ionospheric effects is given.

  7. Imperfect coupling between northern and southern ionospheres: asymmetry in TEC anomalies before earthquakes

    NASA Astrophysics Data System (ADS)

    Jhuang, Hau-Kun; Ho, Yi-Ying; Lee, Lou-Chuang

    2016-04-01

    The northern ionosphere is coupled to the conjugate southern ionosphere through the highly conducting geomagenetic field lines. The coupling is very strong or "perfect" if the geomagnetic field lines are equipotential (the parallel electric field E||=0) and hence the perpendicular electric field (E⊥) at the conjugate sites of both ionospheres are equal. The coupling is "imperfect" if some of the geomagnetic field lines are non-equipotential (E||≠0). The field-aligned electric field E|| can be associated with electron inertia, pressure gradient and collisions appearing in the form of double layer, kinetic Alfvén waves and finite field-aligned conductivity σ||. We use the Global Ionospheric Maps (GIM) data to examine the conjugate effect of total electron content (TEC) for six significant earthquakes. The anomalous (ΔTEC)source in the source ionosphere and (ΔTEC)conjugate in the conjugate ionosphere are obtained for 85 events before the six earthquakes. The ΔTEC ratio β = (ΔTEC)conjugate / (ΔTEC)source is calculated for each anomaly. For a "perfect" coupling, β=1. There are 85 anomalous events before the six significant earthquakes, with 62 events occurring in the daytime (07-18 LT) and 23 events in the nighttime (19-06 LT). The average value of daytime (07-18 LT) TEC variations in the source ionosphere is |ΔTEC|source =20.13 TECu, while the average value in the nighttime (19-06 LT) ionosphere is |ΔTEC|source=14.43 TECu. The value of ΔTEC ratio β ranges from 0.05 (very weak coupling) to 0.98 (nearly perfect coupling) with an average of 0.52. There are 14 strong coupling cases with β ≥0.8, which take place from 11 LT to 19 LT. The daytime (07-18 LT) β average value is 0.57 and the nighttime (19-06 LT) β average is 0.37. The south-north ionosphere coupling is stronger (weaker) in the daytime (nighttime).

  8. NMobTec-EnvEdu: M-Learning System for Environmental Education

    ERIC Educational Resources Information Center

    Cavus, Nadire

    2008-01-01

    This paper introduced the implementation of a New Mobile Technologies and Environmental Education System (NMobTec-EnvEdu) designed for m-learning environments. The NMobTec-EnvEdu system has been developed to provide environmental education in a collaborative framework to undergraduate students through the Internet using mobile phones. The study…

  9. Validation of measured poleward TEC gradient using multi-station GPS with Artificial Neural Network based TEC model in low latitude region for developing predictive capability of ionospheric scintillation

    NASA Astrophysics Data System (ADS)

    Sur, D.; Paul, A.

    2017-12-01

    The equatorial ionosphere shows sharp diurnal and latitudinal Total Electron Content (TEC) variations over a major part of the day. Equatorial ionosphere also exhibits intense post-sunset ionospheric irregularities. Accurate prediction of TEC in these low latitudes is not possible from standard ionospheric models. An Artificial Neural Network (ANN) based Vertical TEC (VTEC) model has been designed using TEC data in low latitude Indian longitude sector for accurate prediction of VTEC. GPS TEC data from the stations Calcutta (22.58°N, 88.38°E geographic, magnetic dip 32°), Baharampore (24.09°N, 88.25°E geographic, magnetic dip 35°) and Siliguri (26.72°N, 88.39°E geographic; magnetic dip 40°) are used as training dataset for the duration of January 2007-September 2011. Poleward VTEC gradients from northern EIA crest to region beyond EIA crest have been calculated from measured VTEC and compared with that obtained from ANN based VTEC model. TEC data from Calcutta and Siliguri are used to compute VTEC gradients during April 2013 and August-September 2013. It has been observed that poleward VTEC gradient computed from ANN based TEC model has shown good correlation with measured values during vernal and autumnal equinoxes of high solar activity periods of 2013. Possible correlation between measured poleward TEC gradients and post-sunset scintillations (S4 ≥ 0.4) from northern crest of EIA has been observed in this paper. From the observation, a suitable threshold poleward VTEC gradient has been proposed for possible occurrence of post-sunset scintillations at northern crest of EIA along 88°E longitude. Poleward VTEC gradients obtained from ANN based VTEC model are used to forecast possible ionospheric scintillation after post-sunset period using the threshold value. It has been observed that these predicted VTEC gradients obtained from ANN based VTEC model can forecast post-sunset L-band scintillation with an accuracy of 67% to 82% in this dynamic low latitude

  10. Linear time series modeling of GPS-derived TEC observations over the Indo-Thailand region

    NASA Astrophysics Data System (ADS)

    Suraj, Puram Sai; Kumar Dabbakuti, J. R. K.; Chowdhary, V. Rajesh; Tripathi, Nitin K.; Ratnam, D. Venkata

    2017-12-01

    This paper proposes a linear time series model to represent the climatology of the ionosphere and to investigate the characteristics of hourly averaged total electron content (TEC). The GPS-TEC observation data at the Bengaluru international global navigation satellite system (GNSS) service (IGS) station (geographic 13.02°N , 77.57°E ; geomagnetic latitude 4.4°N ) have been utilized for processing the TEC data during an extended period (2009-2016) in the 24{th} solar cycle. Solar flux F10.7p index, geomagnetic Ap index, and periodic oscillation factors have been considered to construct a linear TEC model. It is evident from the results that solar activity effect on TEC is high. It reaches the maximum value (˜ 40 TECU) during the high solar activity (HSA) year (2014) and minimum value (˜ 15 TECU) during the low solar activity (LSA) year (2009). The larger magnitudes of semiannual variations are observed during the HSA periods. The geomagnetic effect on TEC is relatively low, with the highest being ˜ 4 TECU (March 2015). The magnitude of periodic variations can be seen more significantly during HSA periods (2013-2015) and less during LSA periods (2009-2011). The correlation coefficient of 0.89 between the observations and model-based estimations has been found. The RMSE between the observed TEC and model TEC values is 4.0 TECU (linear model) and 4.21 TECU (IRI2016 Model). Further, the linear TEC model has been validated at different latitudes over the northern low-latitude region. The solar component (F10.7p index) value decreases with an increase in latitude. The magnitudes of the periodic component become less significant with the increase in latitude. The influence of geomagnetic component becomes less significant at Lucknow GNSS station (26.76°N, 80.88°E) when compared to other GNSS stations. The hourly averaged TEC values have been considered and ionospheric features are well recovered with linear TEC model.

  11. 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

  12. Anamolous ionospheric TEC variations prior to the Indonesian earthquake (M 7.1) of November 15, 2014

    NASA Astrophysics Data System (ADS)

    Alcay, Salih

    2017-05-01

    This paper investigates preearthquake ionospheric variations with the use of TEC of Global Ionospheric Maps (GIMs) and regional maps based on Precise Point Positioning (PPP) during the 7.1-M Indonesian earthquake that occurred on November 15, 2014. TEC maps corresponding to 10 days before to 4 days after the event were examined. In addition, a time series of TEC values according to the PPP maps were also evaluated. In addition to GIMs, it was possible to detect TEC variations with PPP maps. The results showed that ionospheric TEC decreased strikingly 4 days prior to the earthquake. This TEC variation was highly likely related to seismic activity.

  13. Empirical model of TEC response to geomagnetic and solar forcing over Balkan Peninsula

    NASA Astrophysics Data System (ADS)

    Mukhtarov, P.; Andonov, B.; Pancheva, D.

    2018-01-01

    An empirical total electron content (TEC) model response to external forcing over Balkan Peninsula (35°N-50°N; 15°E-30°E) is built by using the Center for Orbit Determination of Europe (CODE) TEC data for full 17 years, January 1999 - December 2015. The external forcing includes geomagnetic activity described by the Kp-index and solar activity described by the solar radio flux F10.7. The model describes the most probable spatial distribution and temporal variability of the externally forced TEC anomalies assuming that they depend mainly on latitude, Kp-index, F10.7 and LT. The anomalies are expressed by the relative deviation of the TEC from its 15-day mean, rTEC, as the mean value is calculated from the 15 preceding days. The approach for building this regional model is similar to that of the global TEC model reported by Mukhtarov et al. (2013a) however it includes two important improvements related to short-term variability of the solar activity and amended geomagnetic forcing by using a "modified" Kp index. The quality assessment of the new constructing model procedure in terms of modeling error calculated for the period of 1999-2015 indicates significant improvement in accordance with the global TEC model (Mukhtarov et al., 2013a). The short-term prediction capabilities of the model based on the error calculations for 2016 are improved as well. In order to demonstrate how the model is able to reproduce the rTEC response to external forcing three geomagnetic storms, accompanied also with short-term solar activity variations, which occur at different seasons and solar activity conditions are presented.

  14. Thermodynamic Analysis of TEG-TEC Device Including Influence of Thomson Effect

    NASA Astrophysics Data System (ADS)

    Feng, Yuanli; Chen, Lingen; Meng, Fankai; Sun, Fengrui

    2018-01-01

    A thermodynamic model of a thermoelectric cooler driven by thermoelectric generator (TEG-TEC) device is established considering Thomson effect. The performance is analyzed and optimized using numerical calculation based on non-equilibrium thermodynamic theory. The influence characteristics of Thomson effect on the optimal performance and variable selection are investigated by comparing the condition with and without Thomson effect. The results show that Thomson effect degrades the performance of TEG-TEC device, it decreases the cooling capacity by 27 %, decreases the coefficient of performance (COP) by 19 %, decreases the maximum cooling temperature difference by 11 % when the ratio of thermoelectric elements number is 0.6, the cold junction temperature of thermoelectric cooler (TEC) is 285 K and the hot junction temperature of thermoelectric generator (TEG) is 450 K. Thomson effect degrades the optimal performance of TEG-TEC device, it decreases the maximum cooling capacity by 28 % and decreases the maximum COP by 28 % under the same junction temperatures. Thomson effect narrows the optimal variable range and optimal working range. In the design of the devices, limited-number thermoelectric elements should be more allocated appropriately to TEG when consider Thomson effect. The results may provide some guidelines for the design of TEG-TEC devices.

  15. A Year-Long Comparison of GPS TEC and Global Ionosphere-Thermosphere Models

    NASA Astrophysics Data System (ADS)

    Perlongo, N. J.; Ridley, A. J.; Cnossen, I.; Wu, C.

    2018-02-01

    The prevalence of GPS total electron content (TEC) observations has provided an opportunity for extensive global ionosphere-thermosphere model validation efforts. This study presents a year-long data-model comparison using the Global Ionosphere-Thermosphere Model (GITM) and the Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM). For the entire year of 2010, each model was run and compared to GPS TEC observations. The results were binned according to season, latitude, local time, and magnetic local time. GITM was found to overestimate the TEC everywhere, except on the midlatitude nightside, due to high O/N2 ratios. TIE-GCM produced much less TEC and had lower O/N2 ratios and neutral wind speeds. Seasonal and regional biases in the models are discussed along with ideas for model improvements and further validation efforts.

  16. South Carolina TEC Student Code.

    ERIC Educational Resources Information Center

    Edwards, C. A., Ed.; Kiser, J. A., Ed.

    This student code has statewide application to South Carolina Technical Colleges and Technical Education Centers (TEC). Provisions are divided into eight articles: (1) General Provisions, including the purpose of a student code, the precept of internal solution of problems, and definitions; (2) Student Rights, including Bill of Rights protections;…

  17. Statistical Analysis of TEC Anomalies Prior to M6.0+ Earthquakes During 2003-2014

    NASA Astrophysics Data System (ADS)

    Zhu, Fuying; Su, Fanfan; Lin, Jian

    2018-04-01

    There are many studies on the anomalous variations of the ionospheric TEC prior to large earthquakes. However, whether or not the morphological characteristics of the TEC anomalies in the daytime and at night are different is rarely studied. In the present paper, based on the total electron content (TEC) data from the global ionosphere map (GIM), we carry out a statistical survey on the spatial-temporal distribution of TEC anomalies before 1339 global M6.0+ earthquakes during 2003-2014. After excluding the interference of geomagnetic disturbance, the temporal and spatial distributions of ionospheric TEC anomalies prior to the earthquakes in the daytime and at night are investigated and compared. Except that the nighttime occurrence rates of the pre-earthquake ionospheric anomalies (PEIAs) are higher than those in the daytime, our analysis has not found any statistically significant difference in the spatial-temporal distribution of PEIAs in the daytime and at night. Moreover, the occurrence rates of pre-earthquake ionospheric TEC both positive anomalies and negative anomalies at night tend to increase slightly with the earthquake magnitude. Thus, we suggest that monitoring the ionospheric TEC changes at night might be a clue to reveal the relation between ionospheric disturbances and seismic activities.

  18. Probability Distribution Extraction from TEC Estimates based on Kernel Density Estimation

    NASA Astrophysics Data System (ADS)

    Demir, Uygar; Toker, Cenk; Çenet, Duygu

    2016-07-01

    Statistical analysis of the ionosphere, specifically the Total Electron Content (TEC), may reveal important information about its temporal and spatial characteristics. One of the core metrics that express the statistical properties of a stochastic process is its Probability Density Function (pdf). Furthermore, statistical parameters such as mean, variance and kurtosis, which can be derived from the pdf, may provide information about the spatial uniformity or clustering of the electron content. For example, the variance differentiates between a quiet ionosphere and a disturbed one, whereas kurtosis differentiates between a geomagnetic storm and an earthquake. Therefore, valuable information about the state of the ionosphere (and the natural phenomena that cause the disturbance) can be obtained by looking at the statistical parameters. In the literature, there are publications which try to fit the histogram of TEC estimates to some well-known pdf.s such as Gaussian, Exponential, etc. However, constraining a histogram to fit to a function with a fixed shape will increase estimation error, and all the information extracted from such pdf will continue to contain this error. In such techniques, it is highly likely to observe some artificial characteristics in the estimated pdf which is not present in the original data. In the present study, we use the Kernel Density Estimation (KDE) technique to estimate the pdf of the TEC. KDE is a non-parametric approach which does not impose a specific form on the TEC. As a result, better pdf estimates that almost perfectly fit to the observed TEC values can be obtained as compared to the techniques mentioned above. KDE is particularly good at representing the tail probabilities, and outliers. We also calculate the mean, variance and kurtosis of the measured TEC values. The technique is applied to the ionosphere over Turkey where the TEC values are estimated from the GNSS measurement from the TNPGN-Active (Turkish National Permanent

  19. LISN: Measurement of TEC values, and TID characteristics over South and Central America (Invited)

    NASA Astrophysics Data System (ADS)

    Valladares, C. E.

    2013-12-01

    The Low-latitude Ionospheric Sensor Network (LISN) is a distributed observatory designed to provide the climatology and weather of the low latitude ionosphere over the South American continent. Presently, the LISN observatory consists of 47 GPS receivers able to transmit TEC and scintillation values to a central server in a real-time basis. Historical TEC values from these receivers and from about 300 other GPSs that operated in South and Central America between 2008 and 2012 were used to derive regional maps of TEC and TIDs. A prominent feature of the TEC maps is the intense day-to-day variability that is observed during all seasons and under quiet and active magnetic conditions. To assess the TEC dependencies a non-linear least-square fit was conducted to simultaneously extract the solar flux, magnetic and seasonal variability for each square cell of the TEC maps and for each 30-min local time sector. It was found that TEC values and the anomaly intensity increase as a function of the solar flux. The latitudinal separation increases with magnetic activity, and TEC values in Central America become the largest when Kp is equal to 5o or more. TIDs are seen quite frequently over the Caribbean region and in the northern part of South America. To calculate the TIDs travel velocities, their propagation direction, and the scale-size of the disturbances a multi-site multi-dimension cross-correlation method was applied to the TEC database. Phase velocities of order 150 m/s and scale sizes between 100 and 400 km were typically observed. This paper will present the morphology and statistics of TIDs as a function of latitude, longitude, local time and season. It is also introduced the results of an investigation to correlate the appearance, phase velocity and angle of propagation of TIDs and tropospheric phenomena observed with the TRMM satellite.

  20. Development of TEC fluctuations in northern and southern hemispheres on the base of GPS observations

    NASA Astrophysics Data System (ADS)

    Shagimuratov, Irk; Krankowski, Andrzej; Sieradzki, Rafal; Ephishov, I. I.

    GPS technique is widely used to study the global structure and dynamics of the ionosphere. In this paper GPS observations carried out at Arctic and Antarctic stations belonging to the IGS network were used to study TEC fluctuations in the high-latitude ionosphere during the ionospheric storms. Dual-frequency GPS phase measurements along individual satellite passes served as raw data. It was shown that ionospheric irregularities of a different scale were devel-oped in the auroral and polar ionosphere. It is a common phenomenon caused phase fluctuations of GPS signals. In November 2009, West Department of IZMIRAN in Kaliningrad (Russia) and University of Warmia and Mazury in Olsztyn (Poland) established computer server for automatic monitoring of these irregularities. The rate of TEC index (ROTI) expressed in TECU/min was used as a measure of TEC fluctuations. During its operation TEC variations related to ionospheric structures of a spatial scale more than 200-300 km were detected. Large-scale ionospheric structures cause an increase in horizontal gradients and difficulties with the carrier phase ambiguity resolution in GPS positioning. In turn, the phase fluctuations can cause cycle-slip effects. At the polar stations, ionospheric structures with TEC enhanced by a factor of 3-5 relative to the background were detected, whereas TEC increased to 5-8 TECU in about 10-15 min. These structures were observed during a storm, as well as during a moderate geomagnetic activity. It can be probably attributed to the polar cap patches. In this study are presented the extended and more detailed analyses of TEC fluctuations in both the northern and southern hemispheres and compare the winter and summer events (November and July 2004 storms). A special attention is given to the features related to TEC fluctuations occur-rence in both hemispheres for conjugated GPS stations. The temporal development of both storms was rather similar. During storms the intensity of irregularities

  1. Detection of Geomagnetic Pulsations of the Earth Using GPS-TEC Data

    NASA Astrophysics Data System (ADS)

    Koroglu, Ozan; Arikan, Feza; Köroǧlu, Meltem; Sabri Ozkazanc, Yakup

    2016-07-01

    The magnetosphere of the Earth is made up of both magnetic fields and plasma. In this layer, plasma waves propagate as Ultra Low Frequency (ULF) waves having mHz scale frequencies. ULF waves are produced due to complicated solar-geomagnetic interactions. In the literature, these ULF waves are defined as pulsations. The geomagnetic pulsations are classified into main two groups as continuous pulsations (Pc) and irregular pulsations (Pi). These pulsations can be determined by ionospheric parameters due to the complex lithosphere-ionosphere-magnetosphere coupling processes. Total Electron Content (TEC) is one of the most important parameters for investigating the variability of ionosphere. Global Positioning System (GPS) provides a cost-effective means for estimating TEC from GPS satellite orbital height of 20,000 km to the ground based receivers. Therefore, the time series of GPS-TEC inherently contains the above mentioned ULF waves. In this study, time series analysis of GPS-TEC is carried out by applying periodogram method to the mid-latitude annual TEC data. After the analysis of GPS-TEC data obtained for GPS stations located in Central Europe and Turkey for 2011, it is observed that some of the fundamental frequencies that are indicators of Pc waves, diurnal and semi-diurnal periodicity and earth-free oscillations can be identified. These results will be used in determination of low frequency trend structure of magnetosphere and ionosphere. Further investigation of remaining relatively low magnitude frequencies, all Pi and Pc can be identified by using time and frequency domain techniques such as wavelet analysis. This study is supported by the joint TUBITAK 115E915 and joint TUBITAK114E092 and AS CR 14/001 projects.

  2. V-TECS Career Cluster Frameworks.

    ERIC Educational Resources Information Center

    Vocational Technical Education Consortium of States, Decatur, GA.

    This document includes 16 vocational-technical crosswalk wheels relating the 14 Vocational Technical Education Consortium of States (V-TECS) Career Families to the 16 Career Clusters developed by the U.S. Department of Education. The career clusters are based on the common academic, workplace, and technical knowledge and skills that cut across all…

  3. Epizootic rabbit enteropathy inoculum (TEC4): antibiograms and antibiotic fractionation.

    PubMed

    Huybens, Nathalie; Houeix, Julien; Licois, Dominique; Mainil, Jacques; Marlier, Didier

    2011-01-01

    Epizootic rabbit enteropathy (ERE) emerged and spread in Europe within the last 13 years causing major economical loss. The aims of the study was to evaluate antibiograms of TEC4, an inoculum composed of an extract of intestinal content of affected rabbits, and to test the potential of different antibiotic-based TEC4 fractions to reproduce the disease. Twenty nine different antibiotic discs were incubated for determining bacteria resistance. In a complementary study, nine tubes of liquid medium were inoculated with TEC4, incubated and added individually with amoxicillin/clavulanic acid, bacitracin, ceftiofur, doxycycline, novobiocin, streptomycyin, tylosin, vancomycin and 0.9% saline solution as control. The content of each tube was washed by centrifugation and suspended in saline. The three most effective antibiotics are florfenicol, amoxycillin/clavulanic acid and tylosin. A high concentration of Clostridium sordelli and Bacillus firmus were isolated in all fractions. Species never cultured from TEC4 were identified as Fusobacterium necrogenes (in vancomycin fraction), Cellulomonas sp (in novobiocin fraction) and Bacteroides distasonis (in doxycycline fraction). The ERE was reproduced when bacitracin, doxycycline and 0.9% fractions were inoculated. Rabbits showed ERE clinical signs with the specific drop in daily weight gain.

  4. Investigation of TEC Variations over Mid-Latitude during Quit and Disturbed Days of March 2015

    NASA Astrophysics Data System (ADS)

    Atıcı, Ramazan; Saǧır, Selçuk; Güzel, Esat

    2016-07-01

    The variations during 09-14-March-2015 quit days and 15-20 March 2015 disturbed days of Total Electron Content (TEC) values (provided by IONOLAB group) obtained by analysis the data from Ankara Global Position System (GPS) station of Turkey located at mid-latitude, IRI -2012 model the and IRI-PLUS model are investigated. Also, the variations of the geomagnetic, interplanetary and solar wind parameters are examined. As a result of investigations, TEC values from all three models are not change too much at quit days. Unlike, at the disturbed days, although IRI-2012 and IRI-PLUS TEC values are not change too much, a noticeable change in GPS-TEC values is occurred. GPS-TEC values are rapidly increased on 17-March 2015 to be severe magnetic storm (Dst = -124 nT). Then, on following days it was observed to significantly decrease. Thus, it is said that GPS-TEC values are more sensitive than IRI-2012 and IRI-PLUS models to variations occurred on disturbed days.

  5. Near-Real Time Monitoring of TEC Over Japan at NICT (RWC Tokyo OF ISES)

    NASA Astrophysics Data System (ADS)

    Miyake, W.; Jin, H.

    2010-05-01

    The world wide use of global navigation satellite systems such as GPS offers unique opportunities for a permanent monitoring of the total electron content (TEC) of the ionosphere. We have developed a system of the rapid derivation of TEC from GEONET (a dense GPS receiver network in Japan). In addition to a previous plot of TEC temporal variation over Japan, we have recently developed a near-real-time two-dimensional TEC map and have used it for the daily operation of Space Weather Forecast Center at NICT (Regional Warning Center Tokyo of International Space Environment Service). The TEC map can be used to continuously monitor the ionospheric disturbances over Japan, including spatial and temporal development of ionospheric storms, large-amplitude traveling ionospheric disturbances, and plasma bubbles intruding over Japan, with high time resolution. The development of the real-time monitoring system of TEC enables us to monitor large ionospheric disturbances, ranging from global- to small-scale disturbances, expected in the next solar maximum. The plot and maps are open to the public and are available on http://wdc.nict.go.jp/IONO/index_E.html.

  6. Regional TEC model under quiet geomagnetic conditions and low-to-moderate solar activity based on CODE GIMs

    NASA Astrophysics Data System (ADS)

    Feng, Jiandi; Jiang, Weiping; Wang, Zhengtao; Zhao, Zhenzhen; Nie, Linjuan

    2017-08-01

    Global empirical total electron content (TEC) models based on TEC maps effectively describe the average behavior of the ionosphere. However, the accuracy of these global models for a certain region may not be ideal. Due to the number and distribution of the International GNSS Service (IGS) stations, the accuracy of TEC maps is geographically different. The modeling database derived from the global TEC maps with different accuracy is likely one of the main reasons that limits the accuracy of the new models. Moreover, many anomalies in the ionosphere are geographic or geomagnetic dependent, and as such the accuracy of global models can deteriorate if these anomalies are not fully incorporated into the modeling approach. For regional models built in small areas, these influences on modeling are immensely weakened. Thus, the regional TEC models may better reflect the temporal and spatial variations of TEC. In our previous work (Feng et al., 2016), a regional TEC model TECM-NEC is proposed for northeast China. However, this model is only directed against the typical region of Mid-latitude Summer Nighttime Anomaly (MSNA) occurrence, which is meaningless in other regions without MSNA. Following the technique of TECM-NEC model, this study proposes another regional empirical TEC model for other regions in mid-latitudes. Taking a small area BeiJing-TianJin-Tangshan (JJT) region (37.5°-42.5° N, 115°-120° E) in China as an example, a regional empirical TEC model (TECM-JJT) is proposed using the TEC grid data from January 1, 1999 to June 30, 2015 provided by the Center for Orbit Determination in Europe (CODE) under quiet geomagnetic conditions. The TECM-JJT model fits the input CODE TEC data with a bias of 0.11TECU and a root mean square error of 3.26TECU. Result shows that the regional model TECM-JJT is consistent with CODE TEC data and GPS-TEC data.

  7. Comparison of Plateletpheresis on the Fenwal Amicus and Fresenius Com.Tec Cell Separators.

    PubMed

    Altuntas, Fevzi; Sari, Ismail; Kocyigit, Ismail; Kaynar, Leylagul; Hacioglu, Sibel; Ozturk, Ahmet; Oztekin, Mehmet; Solmaz, Musa; Eser, Bulent; Cetin, Mustafa; Unal, Ali

    2008-01-01

    SUMMARY: BACKGROUND: A variety of apheresis devices are now available on the market for plateletapheresis. We compared two apheresis instruments (Fenwal Amicus and Fresenius COM.TEC) with regard to processing time, platelet (PLT) yield and efficiency, and white blood cell (WBC) content. MATERIAL AND METHODS: Donors undergoing plateletpheresis were randomly separated into two groups (either the Amicus or the COM.TEC cell separator). RESULTS: In the pre-apheresis setting, 32 plateletpheresis procedures performed with each instrument revealed no significant differences in donors' sex, age, weight, height and total blood volume between the two groups. However, the pre-apheresis PLT count was higher with the COM.TEC than with the Amicus (198 × 10(3)/μl vs. 223 × 10(3)/μl; p = 0.035). The blood volume processed to reach a target PLT yield of ≥3.3 × 10(11) was higher in the COM.TEC compared to the Amicus (3,481 vs. 2,850 ml; p < 0.001). The median separation time was also significantly longer in the COM.TEC than in the Amicus (61 vs. 44 min; p < 0.001). 91 and 88% of the PLT products collected with the Amicus and the COM.TEC, respectively, had a PLT count of >3.3 × 10(11) (p = 0.325). All products obtained with both instruments had WBC counts lower than 5 ↔ 10(6), as required. There was no statistical difference with regard to collection efficiency between the devices (55 ± 15 vs. 57 ± 15%; p = 0.477). However, the collection rate was significantly higher with the Amicus compared to the COM.TEC instrument (0.077 ± 0.012 × 10(11) vs. 0.057 ± 0.008 × 10(11) PLT/min; p < 0.001). CONCLUSION: Both instruments collected platelets efficiently. Additionally, consistent leukoreduction was obtained with both instruments; however, compared with the COM.TEC instrument, the Amicus reached the PLT target yield more quickly.

  8. Observations of the Weddell Sea Anomaly in the ground-based and space-borne TEC measurements

    NASA Astrophysics Data System (ADS)

    Zakharenkova, Irina; Cherniak, Iurii; Shagimuratov, Irk

    2017-08-01

    The Weddell Sea Anomaly (WSA) is a summer ionospheric anomaly, which is characterized by a greater nighttime ionospheric density than that in daytime in the region near the Weddell Sea. We investigate the WSA signatures in the ground-based TEC (vertical total electron content) by using GPS and GLONASS measurements of the dense regional GNSS networks in South America. We constructed the high-resolution regional TEC maps for December 2014-January 2015. The WSA effects of the TEC exceed the noontime values are registered starting from 17 LT, it reaches its maximum at 01-05 LT and starts to disappear after 09 LT. Maximal TEC enhancements were as large as a factor of 2.5-3.5 and were registered at 03-04 LT. This effect was mainly localized in the geographical region of 55°S-75°S latitude and 80°W-30°W longitude, close to the Antarctic Peninsula. Further, we examined the WSA occurrence in the topside ionosphere by using GPS measurements from a zenith-looking GPS antenna on board three Swarm satellites to determine topside TEC (above ∼500 km altitude) at the topside ionosphere-plasmasphere system. Global maps of the topside TEC indicated that the zone with significant WSA effect in the topside TEC (TEC increase ∼2-4 times the noontime level) had a large spatial extent over southern Pacific and Atlantic Ocean. It was observed around 150°W-20°W and between 40°S and 70°S during 23 LT - 06 LT. For the first time, the WSA signatures were shown in the topside TEC data derived from the GPS measurements onboard the Swarm constellation. Independently, two other instruments - FORMOSAT-3/COSMIC radio occultation electron density profiles and in situ measurements by the Langmuir Probe instrument onboard Swarm satellites - were able to confirm: (1) the same location of the WSA zone as revealed in Swarm TEC; (2) the most-pronounced WSA effect, as a maximal electron density exceed over the noontime values, corresponds to altitudes above 400-500 km.

  9. Application of Geostationary GNSS and SBAS Satellites for Studying Ionospheric TEC Disturbances of Geomagnetic and Meteorological Origin

    NASA Astrophysics Data System (ADS)

    Padokhin, A. M.; Kurbatov, G. A.; Yasyukevich, Y.; Yasyukevich, A.

    2017-12-01

    With the development of GNSS and SBAS constellations, the coherent multi-frequency L band transmissions are now available from a number of geostationary satellites. These signals can be used for ionospheric TEC estimations in the same way as widely used GPS/GLONASS signals. In this work, we compare noise patterns in TEC estimations based on different geostationary satellites data: augmentation systems (Indian GAGAN, European EGNOS and American WAAS), and Chinese COMPASS/Beidou navigation system. We show that noise level in geostationary COMPASS/Beidou TEC estimations is times smaller than noise in SBAS TEC estimation and corresponds to those of GPS/GLONASS at the same elevation angles. We discuss the capabilities of geostationary TEC data for studying ionospheric variability driven by space weather and meteorological sources at different time scales. Analyzing data from IGS/MGEX receivers we present geostationary TEC response on X-class Solar flares of current cycle, moderate and strong geomagnetic storms, including G4 St. Patrick's day Storm 2015 and recent G3 storm of the end of May 2017. We also discuss geostationary TEC disturbances in near equatorial ionosphere caused by two SSW events (minor and major final warming of 2015-2016 winter season) as well as geostationary TEC response on typhoons activity near Taiwan in autumn 2016. Our results show large potential of geostationary TEC estimations with GNSS and SBAS signals for continuous ionospheric monitoring.

  10. Receiver DCB estimation and GPS vTEC study at a low latitude station in the South Pacific

    NASA Astrophysics Data System (ADS)

    Prasad, Ramendra; Kumar, Sushil; Jayachandran, P. T.

    2016-11-01

    The statistical estimation of receiver differential code bias (DCB) of the GSV4004B receiver at a low latitude station, Suva (lat. 18.15°S, long. 178.45°E, Geomag. Lat. 21.07°S), Fiji, and the subsequent behaviour of vTEC, are presented. By means of least squares linear regression fitting technique, the receiver DCB was determined using the GPS vTEC data recorded during the year 2010, CODE TEC and IRI-2012 model for 2010. To substantiate the results, minimization of the standard deviation (SD) method was also used for GPS vTEC data. The overall monthly DCB was estimated to be in the range of 62.6 TECU. The vTEC after removing the resultant monthly DCB was consistent with other low latitude observations. The GPS vTEC 2010 data after eliminating the resultant DCB were lower in comparison to Faraday rotation vTEC measurements at Suva during 1984 primarily due to higher solar activity during 1984 as compared to 2010. Seasonally, vTEC was maximum during summer and minimum during winter. The winter showed least vTEC variability whereas equinox showed the largest daytime variability. The geomagnetic disturbances effect showed that both vTEC and its variability were higher on magnetically disturbed days as compared to quiet days with maximum variability in the daytime. Two geomagnetic storms of moderate strengths with main phases in the local daytime showed long duration (∼52 h) increase in vTEC by 33-67% which can be accounted by changes in E×B drifts due to prompt penetration of storm-time auroral electric field in the daytime and disturbance dynamo electric field in the nighttime to low latitudes.

  11. Regional ionospheric TEC data assimilation and now-casting service

    NASA Astrophysics Data System (ADS)

    Aa, E.; Liu, S.; Wengeng, H.

    2017-12-01

    Ionospheric data assimilation is a now-casting technique to incorporate irregular ionospheric measurements into certain background model, which is an effective and efficient way to overcome the limitation of the unbalanced data distribution and to improve the accuracy of the model, so that the model and the data can be optimally combined with each other to produce a more reliable and reasonable system specification. In this study, a regional total electron content (TEC) now-casting system over China and adjacent areas (70E-140E and 15N-55N) is developed on the basis of data assimilation technique. The International Reference Ionosphere (IRI) is used here as background model, and the GNSS data are derived from both the Space Environment Monitoring Network of Chinese Academy of Sciences (SEMnet) and International GNSS Service (IGS) data. A Three-dimensional variation algorithm (3DVAR) combined with Gauss-Markov Kalman filter technique is used to implement the data assimilation. The regional gridded TEC maps and the position errors of single-frequency GPS receivers can be generated and publicized online (http://sepc.ac.cn/TEC_chn.php) in quasi-real time, which is updated for every 15 min. It is one of the ionospheric now-casting systems in China based on data assimilation algorithm, which can be used not only for real-time monitoring of ionosphere environment over China and adjacent areas, but also in providing accurate and effective specification of regional ionospheric TEC and error correction for satellite navigation, radar imaging, shortwave communication, and other relevant applications.

  12. Short-term estimation of GNSS TEC using a neural network model in Brazil

    NASA Astrophysics Data System (ADS)

    Ferreira, Arthur Amaral; Borges, Renato Alves; Paparini, Claudia; Ciraolo, Luigi; Radicella, Sandro M.

    2017-10-01

    This work presents a novel Neural Network (NN) model to estimate Total Electron Content (TEC) from Global Navigation Satellite Systems (GNSS) measurements in three distinct sectors in Brazil. The purpose of this work is to start the investigations on the development of a regional model that can be used to determine the vertical TEC over Brazil, aiming future applications on a near real-time frame estimations and short-term forecasting. The NN is used to estimate the GNSS TEC values at void locations, where no dual-frequency GNSS receiver that may be used as a source of data to GNSS TEC estimation is available. This approach is particularly useful for GNSS single-frequency users that rely on corrections of ionospheric range errors by TEC models. GNSS data from the first GLONASS network for research and development (GLONASS R&D network) installed in Latin America, and from the Brazilian Network for Continuous Monitoring of the GNSS (RMBC) were used on TEC calibration. The input parameters of the NN model are based on features known to influence TEC values, such as geographic location of the GNSS receiver, magnetic activity, seasonal and diurnal variations, and solar activity. Data from two ten-days periods (from DoY 154 to 163 and from 282 to 291) are used to train the network. Three distinct analyses have been carried out in order to assess time-varying and spatial performance of the model. At the spatial performance analysis, for each region, a set of stations is chosen to provide training data to the NN, and after the training procedure, the NN is used to estimate vTEC behavior for the test station which data were not presented to the NN in training process. An analysis is done by comparing, for each testing station, the estimated NN vTEC delivered by the NN and reference calibrated vTEC. Also, as a second analysis, the network ability to forecast one day after the time interval (DoY 292) based on information of the second period of investigation is also assessed

  13. CEDAR-GEM Challenge for Systematic Assessment of Ionosphere/Thermosphere Models in Predicting TEC During the 2006 December Storm Event

    NASA Astrophysics Data System (ADS)

    Shim, J. S.; Rastätter, L.; Kuznetsova, M.; Bilitza, D.; Codrescu, M.; Coster, A. J.; Emery, B. A.; Fedrizzi, M.; Förster, M.; Fuller-Rowell, T. J.; Gardner, L. C.; Goncharenko, L.; Huba, J.; McDonald, S. E.; Mannucci, A. J.; Namgaladze, A. A.; Pi, X.; Prokhorov, B. E.; Ridley, A. J.; Scherliess, L.; Schunk, R. W.; Sojka, J. J.; Zhu, L.

    2017-10-01

    In order to assess current modeling capability of reproducing storm impacts on total electron content (TEC), we considered quantities such as TEC, TEC changes compared to quiet time values, and the maximum value of the TEC and TEC changes during a storm. We compared the quantities obtained from ionospheric models against ground-based GPS TEC measurements during the 2006 AGU storm event (14-15 December 2006) in the selected eight longitude sectors. We used 15 simulations obtained from eight ionospheric models, including empirical, physics-based, coupled ionosphere-thermosphere, and data assimilation models. To quantitatively evaluate performance of the models in TEC prediction during the storm, we calculated skill scores such as RMS error, Normalized RMS error (NRMSE), ratio of the modeled to observed maximum increase (Yield), and the difference between the modeled peak time and observed peak time. Furthermore, to investigate latitudinal dependence of the performance of the models, the skill scores were calculated for five latitude regions. Our study shows that RMSE of TEC and TEC changes of the model simulations range from about 3 TECU (total electron content unit, 1 TECU = 1016 el m-2) (in high latitudes) to about 13 TECU (in low latitudes), which is larger than latitudinal average GPS TEC error of about 2 TECU. Most model simulations predict TEC better than TEC changes in terms of NRMSE and the difference in peak time, while the opposite holds true in terms of Yield. Model performance strongly depends on the quantities considered, the type of metrics used, and the latitude considered.

  14. Ionospheric TEC Weather Map Over South America

    NASA Astrophysics Data System (ADS)

    Takahashi, H.; Wrasse, C. M.; Denardini, C. M.; Pádua, M. B.; de Paula, E. R.; Costa, S. M. A.; Otsuka, Y.; Shiokawa, K.; Monico, J. F. Galera; Ivo, A.; Sant'Anna, N.

    2016-11-01

    Ionospheric weather maps using the total electron content (TEC) monitored by ground-based Global Navigation Satellite Systems (GNSS) receivers over South American continent, TECMAP, have been operationally produced by Instituto Nacional de Pesquisas Espaciais's Space Weather Study and Monitoring Program (Estudo e Monitoramento Brasileiro de Clima Especial) since 2013. In order to cover the whole continent, four GNSS receiver networks, (Rede Brasileiro de Monitoramento Contínuo) RBMC/Brazilian Institute for Geography and Statistics, Low-latitude Ionospheric Sensor Network, International GNSS Service, and Red Argentina de Monitoreo Satelital Continuo, in total 140 sites, have been used. TECMAPs with a time resolution of 10 min are produced in 12 h time delay. Spatial resolution of the map is rather low, varying between 50 and 500 km depending on the density of the observation points. Large day-to-day variabilities of the equatorial ionization anomaly have been observed. Spatial gradient of TEC from the anomaly trough (total electron content unit, 1 TECU = 1016 el m-2 (TECU) <10) to the crest region (TECU > 80) causes a large ionospheric range delay in the GNSS positioning system. Ionospheric plasma bubbles, their seeding and development, could be monitored. This plasma density (spatial and temporal) variability causes not only the GNSS-based positioning error but also radio wave scintillations. Monitoring of these phenomena by TEC mapping becomes an important issue for space weather concern for high-technology positioning system and telecommunication.

  15. Session Overview and AzTEC Instrument Performance

    NASA Astrophysics Data System (ADS)

    Wilson, Grant; Ade, P. A.; Aretxaga, I.; Austermann, J.; Bock, J. J.; Hughes, D.; Kang, Y.; Kim, S.; Lowenthal, J.; Mauskopf, P.; Scott, K.; Yun, M.

    2006-12-01

    AzTEC is a new 144 element bolometer receiver destined as a first-generation instrument for the Large Millimeter Telescope. >From November 2005 and through January 2006, AzTEC made science observations at the 15m James Clerk Maxwell Telescope (JCMT). Approximately 1/2 of the available time was spent mapping the submillimeter galaxy population in blank and biased fields. Overall, over 1 square degree of sky was mapped with uniform coverage in each of five primary fields making this the largest set of surveys of the submillimeter galaxy population ever performed. Hundreds of new submillimeter galaxies have been detected. Here we discuss the instrument, our mapping technique, and a brief summary of the data reduction process. We conclude with a brief summary of the overall impact of these surveys on our understanding of the submillimeter galaxy population.

  16. Comparison of GPS TEC variations with Holt-Winter method and IRI-2012 over Langkawi, Malaysia

    NASA Astrophysics Data System (ADS)

    Elmunim, N. A.; Abdullah, M.; Hasbi, A. M.; Bahari, S. A.

    2017-07-01

    The Total Electron Content (TEC) is the ionospheric parameter that has the main effect on radio wave propagation. Therefore, it is crucial to evaluate the performance of the TEC models for the further improvement of the ionospheric modelling in equatorial regions. This work presents an analysis of the TEC, derived from the GPS Ionospheric Scintillation and TEC Monitor (GISTM) receiver at the Langkawi station, Malaysia, located at the geographic coordinates of 6.19°N, 99.51°E and the geomagnetic coordinates of 3.39°S, 172.42°E. The diurnal, monthly and seasonal variations in 2014 of the observed GPS-TEC were compared with the statistical Holt-Winter method and a recent version of the International Reference Ionosphere model (IRI-2012), using three different topside options of an electron density, which are the IRI-2001, IRI01-corr and NeQuick. The maximum peaks of the GPS-TEC were observed in the post-noon time and the minimum was observed during the early morning time. In addition, in monthly variations the Holt-Winter and the IRI-2012 topside options showed an underestimation that was in agreement with the GPS-TEC, except for the IRI-2001 model which showed an overestimation in June, July and August. Regarding the seasonal variation of the GPS-TEC, the lowest values were observed during summer and it reached its maximum value during the equinox season. The IRI-2001 showed the highest value of percentage deviation compared to the IRI01-corr, NeQuick and Holt-Winter method. Therefore, the accuracy of the models was found to be approximately 95% in the Holt-Winter method, 75% in the IRI01-corr, 73% in the NeQuick and 66% in the IRI-2001 model. Hence, it can be inferred that the Holt-Winter method showed a higher performance and better estimates of the TEC compared to the IRI01-corr and NeQuick, while the IRI-2001 showed a poor predictive performance in the equatorial region over Malaysia.

  17. Imaging the topside ionosphere and plasmasphere with ionospheric tomography using COSMIC GPS TEC

    NASA Astrophysics Data System (ADS)

    Pinto Jayawardena, Talini S.; Chartier, Alex T.; Spencer, Paul; Mitchell, Cathryn N.

    2016-01-01

    GPS-based ionospheric tomography is a well-known technique for imaging the total electron content (TEC) between GPS satellites and receivers. However, as an integral measurement of electron concentration, TEC typically encompasses both the ionosphere and plasmasphere, masking signatures from the topside ionosphere-plasmasphere due to the dominant ionosphere. Imaging these regions requires a technique that isolates TEC in the topside ionosphere-plasmasphere. Multi-Instrument Data Analysis System (MIDAS) employs tomography to image the electron distribution in the ionosphere. Its implementation for regions beyond is yet to be seen due to the different dynamics present above the ionosphere. This paper discusses the extension of MIDAS to image these altitudes using GPS phase-based TEC measurements and follows the work by Spencer and Mitchell (2011). Plasma is constrained to dipole field lines described by Euler potentials, resulting in a distribution symmetrical about the geomagnetic equator. A simulation of an empirical plasmaspheric model by Gallagher et al. (1988) is used to verify the technique by comparing reconstructions of the simulation with the empirical model. The Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) is used as GPS receiver locations. The verification is followed by a validation of the modified MIDAS algorithm, where the regions' TEC is reconstructed from COSMIC GPS phase measurements and qualitatively compared with previous studies using Jason-1 and COSMIC data. Results show that MIDAS can successfully image features/trends of the topside ionosphere-plasmasphere observed in other studies, with deviations in absolute TEC attributed to differences in data set properties and the resolution of the images.

  18. The 1980 V-TECS Marketing Study.

    ERIC Educational Resources Information Center

    Hattwick, Richard E.; And Others

    The Vocational-Technical Education Consortium of States (V-TECS) conducted a marketing study that considered the implications of six options for the organization's future. The first option is continuation of the status quo, which is dangerous because existing members may leave the consortium. The second option is the status quo combined with an…

  19. An empirical model of ionospheric total electron content (TEC) near the crest of the equatorial ionization anomaly (EIA)

    NASA Astrophysics Data System (ADS)

    Hajra, Rajkumar; Chakraborty, Shyamal Kumar; Tsurutani, Bruce T.; DasGupta, Ashish; Echer, Ezequiel; Brum, Christiano G. M.; Gonzalez, Walter D.; Sobral, José Humberto Andrade

    2016-07-01

    We present a geomagnetic quiet time (Dst > -50 nT) empirical model of ionospheric total electron content (TEC) for the northern equatorial ionization anomaly (EIA) crest over Calcutta, India. The model is based on the 1980-1990 TEC measurements from the geostationary Engineering Test Satellite-2 (ETS-2) at the Haringhata (University of Calcutta, India: 22.58° N, 88.38° E geographic; 12.09° N, 160.46° E geomagnetic) ionospheric field station using the technique of Faraday rotation of plane polarized VHF (136.11 MHz) signals. The ground station is situated virtually underneath the northern EIA crest. The monthly mean TEC increases linearly with F10.7 solar ionizing flux, with a significantly high correlation coefficient (r = 0.89-0.99) between the two. For the same solar flux level, the TEC values are found to be significantly different between the descending and ascending phases of the solar cycle. This ionospheric hysteresis effect depends on the local time as well as on the solar flux level. On an annual scale, TEC exhibits semiannual variations with maximum TEC values occurring during the two equinoxes and minimum at summer solstice. The semiannual variation is strongest during local noon with a summer-to-equinox variability of ~50-100 TEC units. The diurnal pattern of TEC is characterized by a pre-sunrise (0400-0500 LT) minimum and near-noon (1300-1400 LT) maximum. Equatorial electrodynamics is dominated by the equatorial electrojet which in turn controls the daytime TEC variation and its maximum. We combine these long-term analyses to develop an empirical model of monthly mean TEC. The model is validated using both ETS-2 measurements and recent GNSS measurements. It is found that the present model efficiently estimates the TEC values within a 1-σ range from the observed mean values.

  20. Where does the plasmasphere begin? Revisit to topside ionospheric profiles in comparison with plasmaspheric TEC from Jason-1

    NASA Astrophysics Data System (ADS)

    Lee, Han-Byul; Kim, Yong Ha; Kim, Eunsol; Hong, Junseok; Kwak, Young-Sil

    2016-10-01

    Topside ionospheric profiles have been measured by Alouette 1 and ISIS 1/2 in the periods of 1962-1972 and 1972-1979, respectively. The profiles cover from the orbital altitude of 1000 km to the F2 peak and show large variations over local time, latitude, and seasons. We here analyze these variations in comparison with plasmaspheric total electron contents (pTECs) that were measured by Jason-1 satellite from the altitude of 1336 km to 20,200 km (GPS orbit). The scale heights of the profiles are generally smaller in the daytime than nighttime but show large day-to-day variations, implying that the ionospheric profiles at 1000 km are changing dynamically, rather than being in diffusive equilibrium. We also derived transition heights between O+ and H+, which show a clear minimum at dawn for low-latitude profiles due to decreasing O+ density at night. To compare with pTEC, we compute topside ionospheric total electron content (tiTEC) by integrating over 800-1336 km using the slope of the profiles. The tiTEC varies in a clear diurnal pattern from 0.3 to 1 and 3 total electron content unit (TECU, 1 TECU = 1016 el m-2) for low and high solar activity, respectively, whereas Jason-1 pTEC values are distributed over 2-6 TECU and 4-8 TECU for low and high solar activity, respectively, with no apparent diurnal modulation. Latitudinal variations of tiTEC show distinctive hemispheric asymmetry while that of Jason-1 pTEC is closely symmetric about the magnetic equator. The local time and latitudinal variations of tiTEC basically resemble those of the ionosphere but are characteristically different from those of Jason-1 pTEC. Based on the difference between tiTEC and pTEC variations, we propose that the region above 1300 km should be considered as the plasmasphere. Lower altitudes for the base of "plasmaspheric TEC," as used in some studies, would cause contamination of ionospheric influence.

  1. Simultaneous response of NmF2 and GPS-TEC to storm events at Ilorin

    NASA Astrophysics Data System (ADS)

    Joshua, B. W.; Adeniyi, J. O.; Oladipo, O. A.; Doherty, P. H.; Adimula, I. A.; Olawepo, A. O.; Adebiyi, S. J.

    2018-06-01

    A comparative study of both TEC and NmF2 variations during quiet and disturbed conditions has been investigated using simultaneous measurements from dual frequency Global Positioning System (GPS) receiver and a DPS-4 Digisonde co-located at Ilorin (Geog. Lat. 8.50°N, Long. 4.50°E, dip. - 7.9°). The results of the quiet time variations of the two parameters show some similarities as well as differences in their structures. The values of both parameters generally increase during the sunrise period attaining a peak around the noon and then decaying towards the night time. The onset time of the sunrise growth is observed to be earlier in TEC than in NmF2. The rate of decay of TEC was observed to be faster than that of the NmF2 in most cases. Also, the noon 'bite-outs', leading to the formation of pre-noon and post-noon peaks, are prominent in the NmF2 structure and was hardly noticed in TEC. Results of the variations of both TEC and NmF2 during the 5 April, 10 May and 3 August 2010 geomagnetic storm events showed a simultaneous deviations of both parameters from the quiet time behavior. The magnitude of the deviations is however most pronounced in NmF2 structure than in TEC. We also found that the enhancement observed in the two parameters during the storm events generally corresponds to decrease in hmF2.

  2. B/TEC Opens Doors for You.

    ERIC Educational Resources Information Center

    Business and Technician Education Council, London (England).

    This package contains a paper summarizing the aims and services provided by the Business and Technician Education Council (B/TEC). Established to advance the quality and availability of a wide range of employment-related education to persons in the United Kingdom who are studying at or beyond the equivalent of the American associate-degree level,…

  3. Industrial Maintenance Technology (IM-TEC). Student Manual.

    ERIC Educational Resources Information Center

    Fusch, Gene E.

    This student manual explains an innovative strategy through which Bellingham Technical College's (Washington) evening Industrial Electrician and Millwright Apprenticeships were aggregated with workforce upgrade course offerings to form the college's first evening degree program in Industrial Maintenance Technology (IM-TEC). Section 1 contains a…

  4. Early Experience with Technology-Based Eye Care Services (TECS): A Novel Ophthalmologic Telemedicine Initiative.

    PubMed

    Maa, April Y; Wojciechowski, Barbara; Hunt, Kelly J; Dismuke, Clara; Shyu, Jason; Janjua, Rabeea; Lu, Xiaoqin; Medert, Charles M; Lynch, Mary G

    2017-04-01

    The aging population is at risk of common eye diseases, and routine eye examinations are recommended to prevent visual impairment. Unfortunately, patients are less likely to seek care as they age, which may be the result of significant travel and time burdens associated with going to an eye clinic in person. A new method of eye-care delivery that mitigates distance barriers and improves access was developed to improve screening for potentially blinding conditions. We present the quality data from the early experience (first 13 months) of Technology-Based Eye Care Services (TECS), a novel ophthalmologic telemedicine program. With TECS, a trained ophthalmology technician is stationed in a primary care clinic away from the main hospital. The ophthalmology technician follows a detailed protocol that collects information about the patient's eyes. The information then is interpreted remotely. Patients with possible abnormal findings are scheduled for a face-to-face examination in the eye clinic. Any patient with no known ocular disease who desires a routine eye screening examination is eligible. Technology-Based Eye Care Services was established in 5 primary care clinics in Georgia surrounding the Atlanta Veterans Affairs hospital. Four program operation metrics (patient satisfaction, eyeglass remakes, disease detection, and visit length) and 2 access-to-care metrics (appointment wait time and no-show rate) were tracked. Care was rendered to 2690 patients over the first 13 months of TECS. The program has been met with high patient satisfaction (4.95 of 5). Eyeglass remake rate was 0.59%. Abnormal findings were noted in 36.8% of patients and there was >90% agreement between the TECS reading and the face-to-face findings of the physician. TECS saved both patient (25% less) and physician time (50% less), and access to care substantially improved with 99% of patients seen within 14 days of contacting the eye clinic, with a TECS no-show rate of 5.2%. The early experience with

  5. Equatorial late-afternoon periodic TEC fluctuations observed by multiple GPS receivers

    NASA Astrophysics Data System (ADS)

    Tsugawa, T.; Maruyama, T.; Saito, S.; Ishii, M.

    2009-12-01

    We report, for the first time, equatorial periodic total electron content (TEC) fluctuations observed in the late afternoon by multiple GPS receivers. As a part of Southeast Asia low-latitude ionospheric network (SEALION), GPS receivers at Chiang Mai and Chumphon, Thailand, have been operated since 2005. We found that periodic TEC fluctuations (PTF) with the periods of 15-30 minutes are often observed at these two sites in the spring (Apr-May) late afternoon. Further investigations using multiple GPS receivers in Southeast Asia revealed that the PTFs propagate at 150-200 m/s away from the equator and their amplitudes depend on the satellite azimuth angle. Statistical study of the PTF activity at different latitudes and longitudes clarified that the PTFs are not observed at mid-latitudes, and their seasonal variations are different at different longitudes and at geomagnetically conjugate regions. These observational results indicate that the PTFs are caused by the atmospheric gravity waves (AGW) which are generated in the equatorial lower atmosphere and propagate away from the equator. Simultaneous GPS-TEC and ionosonde observations at Chumphon revealed that the day-to-day variations of PTF activities are well correlated with those of the rate of TEC change index (ROTI) and the occurrence of equatorial spread F (ESF) after the sunset, indicating the PTFs may be related with the onset of the ESF and plasma bubbles.

  6. Comparison of plateletpheresis on the Fenwal Amicus, Fresenius COM.TEC, and Trima Accel Cell separators.

    PubMed

    Keklik, Muzaffer; Eser, Bulent; Kaynar, Leylagul; Sivgin, Serdar; Keklik, Ertugrul; Solmaz, Musa; Ozturk, Ahmet; Buyukoglan, Ruksan; Yay, Mehmet; Cetin, Mustafa; Unal, Ali

    2015-06-01

    Blood component donations by apheresis have become more common in modern blood transfusion practices. We compared three apheresis instruments (Fenwal Amicus, Fresenius COM.TEC, and Trima Accel) with regard to platelet (PLT) yield, collection efficiency (CE), and collection rate (CR). The single-needle or double-needle plateletpheresis procedures of the three instruments were compared in a retrospective, randomized study in 270 donors. The blood volume processed was higher in the COM.TEC compared with the Amicus and Trima. Also there was a significantly higher median volume of ACD used in collections on the COM.TEC compared with the Amicus and Trima. The PLT yield was significantly lower with the COM.TEC compared with the Amicus and Trima. Additionally, the CE was significantly lower with the COM.TEC compared with the Amicus and Trima. There was no significant difference in median separation time and CR between the three groups. When procedures were compared regarding CE by using Amicus device, it was significantly higher in single-needle than double-needle plateletpheresis. When double-needle Amicus system was compared with double-needle COM.TEC system, CE and PLT yield were significantly higher with Amicus system. When single-needle Amicus system was compared with single-needle Trima system, CE and PLT yield were significantly higher with Trima system. All instruments collected PLTs efficiently. However, the CE was lower with the COM.TEC compared with the Amicus and Trima. Also, we found Amicus single-needle system collected PLTs more efficiently compared with the double-needle system. CE and PLT yields were significantly higher with the single-needle Trima instrument compared with the single-needle Amicus device. © 2014 Wiley Periodicals, Inc.

  7. Investigation of the TEC Changes in the vicinity of the Earthquake Preparation Zone

    NASA Astrophysics Data System (ADS)

    Ulukavak, Mustafa; Yalcinkaya, Mualla

    2016-04-01

    Recently, investigation of the anomalies in the ionosphere before the earthquake has taken too much attention. The Total Electron Content (TEC) data has been used to monitor the changes in the ionosphere. Hence, researchers use the TEC changes before the strong earthquakes to monitor the anomalies in the ionosphere. In this study, the GPS-TEC variations, obtained from the GNSS stations in the vicinity of the earthquake preparation zone, was investigated. Nidra earthquake (M6.5), which was occurred on the north-west of Greece on November 17th, 2015 (38.755°N, 20.552°E), was selected for this study. First, the equation proposed by Dobrovolsky et al. (1979) was used to calculate the radius of the earthquake preparation zone. International GNSS Service (IGS) stations in the region were classified with respect to the radius of the earthquake preparation zone. The observation data of each station was obtained from the Crustal Dynamics Data and Information System (CDDIS) archive to estimate GPS-TEC variations between 16 October 2015 and 16 December 2015. Global Ionosphere Maps (GIM) products, obtained from the IGS, was used to check the robustness of the GPS-TEC variations. Possible anomalies were analyzed for each GNSS station by using the 15-day moving median method. In order to analyze these pre-earthquake ionospheric anomalies, we investigated three indices (Kp, F10.7 and Dst) related to the space weather conditions between 16 October 2015 and 16 December 2015. Solar and geomagnetic indices were obtained from The Oceanic and Atmospheric Administration (NOAA), The Canadian Space Weather Forecast Centre (CSWFC), and the Data Analysis Center for Geomagnetism and Space Magnetism Graduate School of Science, Kyoto University (WDC). This study aims at investigating the possible effects of the earthquake on the TEC variations.

  8. DKK1 mediated inhibition of Wnt signaling in postnatal mice leads to loss of TEC progenitors and thymic degeneration.

    PubMed

    Osada, Masako; Jardine, Logan; Misir, Ruth; Andl, Thomas; Millar, Sarah E; Pezzano, Mark

    2010-02-08

    Thymic epithelial cell (TEC) microenvironments are essential for the recruitment of T cell precursors from the bone marrow, as well as the subsequent expansion and selection of thymocytes resulting in a mature self-tolerant T cell repertoire. The molecular mechanisms, which control both the initial development and subsequent maintenance of these critical microenvironments, are poorly defined. Wnt signaling has been shown to be important to the development of several epithelial tissues and organs. Regulation of Wnt signaling has also been shown to impact both early thymocyte and thymic epithelial development. However, early blocks in thymic organogenesis or death of the mice have prevented analysis of a role of canonical Wnt signaling in the maintenance of TECs in the postnatal thymus. Here we demonstrate that tetracycline-regulated expression of the canonical Wnt inhibitor DKK1 in TECs localized in both the cortex and medulla of adult mice, results in rapid thymic degeneration characterized by a loss of DeltaNP63(+) Foxn1(+) and Aire(+) TECs, loss of K5K8DP TECs thought to represent or contain an immature TEC progenitor, decreased TEC proliferation and the development of cystic structures, similar to an aged thymus. Removal of DKK1 from DKK1-involuted mice results in full recovery, suggesting that canonical Wnt signaling is required for the differentiation or proliferation of TEC populations needed for maintenance of properly organized adult thymic epithelial microenvironments. Taken together, the results of this study demonstrate that canonical Wnt signaling within TECs is required for the maintenance of epithelial microenvironments in the postnatal thymus, possibly through effects on TEC progenitor/stem cell populations. Downstream targets of Wnt signaling, which are responsible for maintenance of these TEC progenitors may provide useful targets for therapies aimed at counteracting age associated thymic involution or the premature thymic degeneration associated

  9. Seismo-Ionospheric Precursor in the GIM TEC of the 24 August 2014 M6 Napa Earthquake

    NASA Astrophysics Data System (ADS)

    Wu, T. Y.; Liu, T. J. Y.; Liu, J. Y.

    2015-12-01

    This study examines seismo-ionospheric precursors (SIPs) in the global ionosphere map (GIM) of the total electron content (TEC) associated with the 24 August 2014 M6 South Napa earthquake and statistical evidence of SIPs of the GPS TEC in western USA during 2000-2014. The temporal SIP in the GIM TEC around the epicenter significantly decreasing (negative anomaly) on 22 August. To discriminate the global effect, such as solar flares, magnetic storms, etc., and the local effect, such as earthquakes, 5183 lattices on the GIM are employed to conduct a global search of the SIP distribution. Anomalies of both GIM TEC and associated gradients specifically and continuously appearing over the epicenter suggest that the SIP relate to the 2014 South Napa earthquake. A simulation is further carried out to produce the SIP in GIM TEC before the earthquake. Results indicate that the eastward electric field generated over the epicenter area during the earthquake preparation period to be essential.

  10. Curriculum Change. An Evaluation of TEC Programme Development in Colleges. The Main Findings.

    ERIC Educational Resources Information Center

    Parkin, Christopher; And Others

    An evaluation was made of the adoption of curriculum changes mandated by the Technician Education Council (TEC) by 78 colleges in England. The study concentrated on the processes of adaptation that occurred in the colleges in order to cope with the degree of change required by TEC. Data were collected via questionnaires, interviews, case studies,…

  11. Review of variations in Mw < 7 earthquake motions on position and TEC (Mw = 6.5 Aegean Sea earthquake sample)

    NASA Astrophysics Data System (ADS)

    Yildirim, Omer; Inyurt, Samed; Mekik, Cetin

    2016-02-01

    Turkey is a country located in the middle latitude zone, where tectonic activity is intensive. Recently, an earthquake of magnitude 6.5 Mw occurred offshore in the Aegean Sea on 24 May 2014 at 09:25 UTC, which lasted about 40 s. The earthquake was also felt in Greece, Romania, and Bulgaria in addition to Turkey. In recent years, ionospheric anomaly detection studies have been carried out because of seismicity with total electron content (TEC) computed from the global navigation satellite system's (GNSS) signal delays and several interesting findings have been published. In this study, both TEC and positional variations have been examined separately following a moderate size earthquake in the Aegean Sea. The correlation of the aforementioned ionospheric variation with the positional variation has also been investigated. For this purpose, a total of 15 stations was used, including four continuously operating reference stations in Turkey (CORS-TR) and stations in the seismic zone (AYVL, CANA, IPSA, and YENC), as well as international GNSS service (IGS) and European reference frame permanent network (EPN) stations. The ionospheric and positional variations of the AYVL, CANA, IPSA, and YENC stations were examined using Bernese v5.0 software. When the precise point positioning TEC (PPP-TEC) values were examined, it was observed that the TEC values were approximately 4 TECU (total electron content unit) above the upper-limit TEC value at four stations located in Turkey, 3 days before the earthquake at 08:00 and 10:00 UTC. At the same stations, on the day before the earthquake at 06:00, 08:00, and 10:00 UTC, the TEC values were approximately 5 TECU below the lower-limit TEC value. The global ionosphere model TEC (GIM-TEC) values published by the Centre for Orbit Determination in Europe (CODE) were also examined. Three days before the earthquake, at all stations, it was observed that the TEC values in the time period between 08:00 and 10:00 UTC were approximately 2 TECU

  12. C-TEC: Ohio's First All-Green School

    ERIC Educational Resources Information Center

    Krall, Angie

    2009-01-01

    In Ohio's Licking County, the Career and Technology Education Centers (C-TEC) is a leader in the green movement. This eco-friendly school incorporates environmental sustainability in all aspects of its programming and is the first Leadership in Energy and Environmental Design (LEED)-certified public building in the state. While eco-friendly…

  13. SynTec Final Technical Report: Synthetic biology for Tailored Enzyme cocktails

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

    Lin, Janine; Teter, Sarah

    Using a novel enzyme screening method inspired by synthetic biology, Novozymes developed new technology under SynTec which allows for more rapidly tailoring of enzyme cocktails. The methodology can be applied to specific feedstocks, and or coupled to address a specific hydrolytic conversion process context. Using combinatorial high throughput screening of libraries of enzyme domains, we can quickly assess which combination of catalytic modules delivers the best performance for a specific condition. To demonstrate the effectiveness of the screening process, we measured performance of the output catalytic cocktail compared to CTec3/HTec3. SynTec benchmark cocktail - blend of Cellic® CTec3 and HTec3.more » The test substrate was - ammonia fiber expansion pretreated corn stover (AFEX™ PCS).CTec3/HTec3 was assayed at the optimal pH and temperature, and also in the absence of any pH adjustment. The new enzyme cocktail discovered under SynTec was assayed in the absence of any pH adjustment and at the optimal temperature. Conversion is delivered by SynTec enzyme at significant dose reduction relative to CTec3/HTec3 at the controlled pH optimum, and without titrant required to maintain pH, which delivers additional cost savings relative to current state of the art process. In this 2.5 year $4M project, the team delivered an experimental cocktail that significantly outperformed CTec3/HTec3 for a specific substrate, and for specific hydrolysis conditions. As a means of comparing performance improvement delivered per research dollar spent, we note that SynTec delivered a similar performance improvement to the previous award, in a shorter time and with fewer resources than for the previously successful DOE project DECREASE, a 3.5 year, $25M project, though this project focused on a different substrate and used different hydrolysis conditions. The newly implemented technology for rapid sourcing of new cellulases and hemicellulases from nature is an example of Novozymes

  14. Long time series analysis of ionospheric TEC disturbance over seismically region in southwest China during low solar activity

    NASA Astrophysics Data System (ADS)

    Yan, Xiangxiang; Yu, Tao; Shan, Xinjian; Liu, Zhan; Wang, Zhenjie

    2016-04-01

    Recently, there are growing interests in studying the seismo-ionospheric disturbance prior to earthquakes, mainly including the anomalies in the electric field, magnetic field and plasma parameters. However, there are still some controversies over this topic, mainly because of strong day-to-day variability of the ionosphere itself. It is hard to determine whether the different forms of ionospheric disturbances are associated with earthquakes or not. Using data of Crustal Movement Observation Network of China (CMONC) and IGS (International GNSS Service), we attempt to give a statistical investigation about the total electron content (TEC) perturbation before 30 Mw6.0+ earthquakes during January 2000 to December 2010 in China. To determine the abnormal TEC signals, a quartile-based process is performed. At each time point we calculated the median M using the TEC values at the same local time for the preceding 15 days. In addition, we calculated the maps of differential TEC from global ionosphere maps (GIM) in the above period. It is shown that TEC anomalies were detected before 20 earthquakes, nearly 67%. The anomalies represent positive before most events and occurred mostly within 2-6 days before the shocks, significantly during the afternoon period, 1200-2000LT. Part of perturbations appeared more than one time. Moreover, the affected area of TEC is not coincide with the vertical projection of the epicenter but shifts equatorward and is controlled by equatorial ionization anomaly (EIA) crest. On the other hand, we analyzed variations of TEC over southwest China during a period of low solar and geomagnetic activity in April-October 2008, based on the data of CMONC. During that time, six large earthquakes with magnitude M≧6.0 occurred around the southwest region of China. The method to detect abnormal TEC signals is same with above statistical study. Known that the decisive role in the ionosphere state is performed by space weather effects, we compared the TEC

  15. Curriculum Change Part 2a. Programme Development in Colleges. Part 2a: The Work Activities of Teachers on TEC Certificate Programmes.

    ERIC Educational Resources Information Center

    Dodd, S.; And Others

    A study examined the day-to-day work activities of teachers of Technician Education Council (TEC) certificate programs in Great Britain. During the study, a detailed questionnaire dealing with the tasks performed by TEC teachers, the amount of time spent on TEC teachers on individual activities, and the impact of the TEC programs on teacher…

  16. The TolTEC Camera for the LMT Telescope

    NASA Astrophysics Data System (ADS)

    Bryan, Sean

    2018-01-01

    TolTEC is a new camera being built for the 50-meter Large Millimeter-wave Telescope (LMT) on Sierra Negra in Puebla, Mexico. The instrument will discover and characterize distant galaxies by detecting the thermal emission of dust heated by starlight. The polarimetric capabilities of the camera will measure magnetic fields in star-forming regions in the Milky Way. The optical design of the camera uses mirrors, lenses, and dichroics to simultaneously couple a 4 arcminute diameter field of view onto three single-band focal planes at 150, 220, and 280 GHz. The 7000 polarization-selective detectors are single-band horn-coupled LEKID detectors fabricated at NIST. A rotating half wave plate operates at ambient temperature to modulate the polarized signal. In addition to the galactic and extragalactic surveys already planned, TolTEC installed at the LMT will provide open observing time to the community.

  17. Reconstruction of missed critical frequency of F2-layer over Mexico using TEC

    NASA Astrophysics Data System (ADS)

    Sergeeva, M. A.; Maltseva, O. A.; Gonzalez-Esparza, A.; Romero Hernandez, E.; De la Luz, V.; Rodriguez-Martinez, M. R.

    2016-12-01

    The study of the Earth's ionosphere's state is one of the key issues within the Space Weather monitoring task. It is hard to overestimate the importance of diagnostics of its current state and forecasts of Space Weather conditions. There are different methods of short-time predictions for the ionosphere state change. The real-time monitoring of the ionospheric Total Electron Content (TEC) provides the opportunity to choose an appropriate technique for the particular observation point on the Earth. From September 2015 the continuous monitoring of TEC variations over the territory of Mexico is performed by the Mexican Space Weather Service (SCiESMEX). Regular patterns of the diurnal and seasonal TEC variations were revealed in base of past statistics and real-time observations which can be used to test the prediction method. Some specific features of the ionosphere behaviour are discussed. However, with all the merits of TEC as an ionospheric parameter, for the full picture of the processes in the ionosphere and for practical applications it is needed to identify the behaviour of other principal ionospheric parameters provided by ionosondes. Currently, SCiESMEX works on the project of the ionosonde installation in Mexico. This study was focused on the reconstruction of the critical frequency of F2-layer of the ionosphere (foF2) when this data is missing. For this purpose measurements of TEC and the median value of the equivalent slab thickness of the ionosphere were used. First, the foF2 values reconstruction was made for the case of the ionosonde data being absent during some hours or days. Second, the possibility of foF2 reconstruction was estimated for the Mexican region having no ionosonde using local TEC data and foF2 data obtained in the regions close to Mexico. Calculations were performed for quiet and disturbed periods. The results of reconstruction were compared to the foF2 obtained from the International Reference Model and to median foF2 values. Comparison

  18. Quantifications of Geomagnetic Storm Impact on TEC and NmF2 during 2013 Mar. event

    NASA Astrophysics Data System (ADS)

    Shim, J. S.; Tsagouri, I.; Goncharenko, L. P.; Mays, M. L.; Taktakishvili, A.; Rastaetter, L.; Kuznetsova, M. M.

    2016-12-01

    We investigate the ionospheric response to 2013 Mar. geomagnetic storm event using GPS TEC, ISR and ionosonde observations in North American sector. In order to quantify variations of TEC and NmF2 (or foF2) due to the storm, we remove the background quiet-time values (e.g., TEC of one day prior to the storm, NmF2 median and average of five quietest days for 30 days prior to the storm). In addition, in order to assess modeling capability of reproducing storm impacts on TEC and NmF2, we compare the observations with various model simulations, which are obtained from empirical, physics-based, and data assimilation models. Further, we investigate how uncertainty in the interplanetary magnetic field (IMF) impacts on TEC and NmF2 during the geomagnetic storm event. For this uncertainty study, we use a physics-based coupled ionosphere-thermosphere model, CTIPe, and solar wind parameters obtained from ensemble of WSA-ENLIL+Cone model simulations. This study has been supported by the Community Coordinated Modeling Center (CCMC) at the Goddard Space Flight Center. Model outputs and observational data used for the study will be permanently posted at the CCMC website (http://ccmc.gsfc.nasa.gov) for the space science communities to use.

  19. Support vector machines for TEC seismo-ionospheric anomalies detection

    NASA Astrophysics Data System (ADS)

    Akhoondzadeh, M.

    2013-02-01

    Using time series prediction methods, it is possible to pursue the behaviors of earthquake precursors in the future and to announce early warnings when the differences between the predicted value and the observed value exceed the predefined threshold value. Support Vector Machines (SVMs) are widely used due to their many advantages for classification and regression tasks. This study is concerned with investigating the Total Electron Content (TEC) time series by using a SVM to detect seismo-ionospheric anomalous variations induced by the three powerful earthquakes of Tohoku (11 March 2011), Haiti (12 January 2010) and Samoa (29 September 2009). The duration of TEC time series dataset is 49, 46 and 71 days, for Tohoku, Haiti and Samoa earthquakes, respectively, with each at time resolution of 2 h. In the case of Tohoku earthquake, the results show that the difference between the predicted value obtained from the SVM method and the observed value reaches the maximum value (i.e., 129.31 TECU) at earthquake time in a period of high geomagnetic activities. The SVM method detected a considerable number of anomalous occurrences 1 and 2 days prior to the Haiti earthquake and also 1 and 5 days before the Samoa earthquake in a period of low geomagnetic activities. In order to show that the method is acting sensibly with regard to the results extracted during nonevent and event TEC data, i.e., to perform some null-hypothesis tests in which the methods would also be calibrated, the same period of data from the previous year of the Samoa earthquake date has been taken into the account. Further to this, in this study, the detected TEC anomalies using the SVM method were compared to the previous results (Akhoondzadeh and Saradjian, 2011; Akhoondzadeh, 2012) obtained from the mean, median, wavelet and Kalman filter methods. The SVM detected anomalies are similar to those detected using the previous methods. It can be concluded that SVM can be a suitable learning method to detect

  20. Inverting Coseismic TEC Disturbances for Neutral Atmosphere Pressure Wave

    NASA Astrophysics Data System (ADS)

    Lee, R. F.; Mikesell, D.; Rolland, L.

    2017-12-01

    Research from the past 20 years has shown that we can detect coseismic disturbances in the total electron content (TEC) using global navigation space systems (GNSS). In the near field, TEC disturbances are created by the direct wave from rupture on the surface. This pressure wave travels through the neutral atmosphere to the ionosphere within about 10 minutes. This provides the opportunity to almost immediately characterize the source of the acoustic disturbance on the surface using methods from seismology. In populated areas, this could provide valuable information to first responders. To retrieve the surface motion amplitude information we must account for changes in the waveform caused by the geomagnetic field, motion of the satellites and the geometry of the satellites and receivers. One method is to use a transfer function to invert for the neutral atmosphere pressure wave. Gómez et al (2015) first employed an analytical model to invert for acoustic waves produced by Rayleigh waves propagating along the Earth's surface. Here, we examine the same model in the near field using the TEC disturbances from the direct wave produced by rupture at the surface. We compare results from the forward model against a numerical model that has been shown to be in good agreement with observations from the 2011 Van (Turkey) earthquake. We show the forward model predictions using both methods for the Van earthquake. We then analyze results for hypothetical events at different latitudes and discuss the reliability of the analytical model in each scenario. Gómez, D., R. Jr. Smalley, C. A. Langston, T. J. Wilson, M. Bevis, I. W. D. Dalziel, E. C. Kendrick, S. A. Konfal, M. J. Willis, D. A. Piñón, et al. (2015), Virtual array beamforming of GPS TEC observations of coseismic ionospheric disturbances near the Geomagnetic South Pole triggered by teleseismic megathrusts, J. Geophys. Res. Space Physics, 120, 9087-9101, doi:10.1002/2015JA021725.

  1. V-TECS Guide for Bookkeeping/Accounting/Payroll Clerk.

    ERIC Educational Resources Information Center

    Gregory, Margaret R.; Benson, Robert T.

    This guide, an extension of the Vocational-Technical Education Consortium of States (V-TECS) catalog, includes such considerations as background information, decision-making skills, attitudes, and learning methods surrounding the occupations of bookkeeper/accountant/payroll clerk. The guide provides job-relevant task, performance objectives,…

  2. Analysis of ionospheric TEC from GNSS observables over the Turkish region and predictability of IRI and SPIM models

    NASA Astrophysics Data System (ADS)

    Ansari, Kutubuddin; Corumluoglu, Ozsen; Panda, Sampad Kumar

    2017-04-01

    The present study investigates the ionospheric Total Electron Content (TEC) variations in the lower mid-latitude Turkish region from the Turkish Permanent GNSS Network (TPGN) and International GNSS Services (IGS) observations during the period from January 2015 to December 2015. The corresponding TEC predicted by the International Reference Ionosphere (IRI 2012) and Standard Plasmasphere-Ionosphere Model (SPIM), and interpolated from Global Ionosphere Maps (GIMs) are evaluated to realize their reliability over the region. We studied the diurnal and monthly behavior of TEC and the relative TEC deviations along with the upper and lower quartiles to represent its spatio-temporal variability. The diurnal variation of GNSS-derived TEC indicates its maximum peak value around 10.00 UT which decreases gradually to attain minimum value after midnight. The monthly maximum value of TEC is observed in March followed by May and August, and the lowest value is seen during September. Studies show that the monthly relative deviation of TEC variability lies in the range of -1 to 4 units for all stations with the maximum difference between positive and negative variability remaining around 5. The studies also cover seasonal variation, grand-mean of ionospheric TEC and TEC intensity from the TPGN. The seasonal ionospheric VTEC pattern over all stations depicts slight increment in VTEC distribution during March equinox compared to September equinox. The December solstice perceived relatively higher VTEC than June solstice. The overall of VTEC values enhanced at all stations towards end of the year 2015 compare to mid of year due the high solar activity. The maximum grand-mean of VTEC is registered in March equinox while the lowest value is seen in September irrespective of all stations. The measured grand-mean intensity variations of VTEC values are in ascending phase during March, May, August and November months, but in descending phase during February, April, June and September

  3. Comparison of double dose plateletpheresis on the Fenwal Amicus, Fresenius COM.TEC and Trima Accel cell separators.

    PubMed

    Keklik, Muzaffer; Eser, Bulent; Kaynar, Leylagul; Solmaz, Musa; Ozturk, Ahmet; Yay, Mehmet; Birekul, Ayse; Oztekin, Mehmet; Sivgin, Serdar; Cetin, Mustafa; Unal, Ali

    2014-10-01

    A variety of apheresis instruments are now available on the market for double dose plateletpheresis. We compared three apheresis devices (Fenwal Amicus, Fresenius COM.TEC and Trima Accel) with regard to processing time, platelet (PLT) yield, collection efficiency (CE) and collection rate (CR). The single-needle or double-needle double plateletpheresis procedures of the three instruments were compared in a retrospective, randomized study in 135 donors. In the pre-apheresis setting, 45 double plateletpheresis procedures performed with each instrument revealed no significant differences in donor's age, sex, weight, hemoglobin, white blood cell and PLT count between three groups. The blood volume processed to reach a target PLT yield of ≥ 6 × 10(11) was higher in the COM.TEC compared with the Amicus and Trima (4394 vs. 3780 and 3340 ml, respectively; p < 0.001). Also there was a significantly higher median volume of ACD used in collections on the COM.TEC compared with the Amicus and Trima (426 vs. 387 and 329 ml, respectively; p < 0.001). There was a significantly higher median time needed for the procedures on the COM.TEC compared with the Amicus and Trima (66 vs. 62 and 63 min, respectively; p = 0.024). The CE was significantly higher with the Trima compared with the Amicus and COM.TEC (83.57 ± 17.19 vs. 66.71 ± 3.47 and 58.79 ± 5.14%, respectively; p < 0.001). Also, there was a significantly higher product volume on the Trima compared with the Amicus and COM.TEC (395.56 vs. 363.11 and 386.4 ml, respectively; p = 0.008). Additionally, the CR was significantly lower with the COM.TEC compared with the Amicus and Trima (0.092 ± 0.011 vs. 0.099 ± 0.013 and 0.097 ± 0.013 plt × 10(11)/min, respectively; p = 0.039). There was no significant differences in PLT yield between the three groups (p = 0.636). Trima single-needle device collected double dose platelets more efficiently than Amicus and

  4. AzTEC/ASTE 1.1 mm Deep Surveys: Number Counts and Clustering of Millimeter-bright Galaxies

    NASA Astrophysics Data System (ADS)

    Hatsukade, B.

    2011-11-01

    We present results of a 1.1 mm deep survey of the AKARI Deep Field South (ADF-S) with AzTEC mounted on the Atacama Submillimetre Telescope Experiment (ASTE). We obtained a map of 0.25 deg2 area with an rms noise level of 0.32-0.71 mJy. This is one of the deepest and widest maps thus far at millimetre and submillimetre wavelengths. We uncovered 198 sources with a significance of 3.5-15.6σ, providing the largest catalog of 1.1 mm sources in a contiguous region. Most of the sources are not detected in the far-infrared bands of the AKARI satellite, suggesting that they are mostly at z ≥ 1.5 given the detection limits. We construct differential and cumulative number counts of the ADF-S, the Subaru/XMM Newton Deep Field (SXDF), and the SSA 22 field surveyed by AzTEC/ASTE, which provide currently the tightest constraints on the faint end. The integration of the differential number counts of the ADF-S find that the contribution of 1.1 mm sources with ≥1 mJy to the cosmic infrared background (CIB) at 1.1 mm is 12-16%, suggesting that the large fraction of the CIB originates from faint sources of which number counts are not yet constrained. We estimate the cosmic star-formation rate density contributed by 1.1 mm sources with ≥1 mJy using the differential number counts and find that it is lower by about a factor of 5-10 compared to those derived from UV/optically-selected galaxies at z ~ 2-3. Clustering analyses of AzTEC sources in the ADF-S and the SXDF find that bright (>3 mJy) AzTEC sources are more strongly clustered than faint (< 3 mJy) AzTEC sources and the average mass of dark halos hosting bright AzTEC sources was calculated to be 1013-1014M⊙. Comparison of correlation length of AzTEC sources with other populations and with a bias evolution model suggests that dark halos hosting bright AzTEC sources evolve into systems of clusters at present universe and the AzTEC sources residing the dark halos evolve into massive elliptical galaxies located in the center of

  5. Application of Modified Particle Swarm Optimization Method for Parameter Extraction of 2-D TEC Mapping

    NASA Astrophysics Data System (ADS)

    Toker, C.; Gokdag, Y. E.; Arikan, F.; Arikan, O.

    2012-04-01

    Ionosphere is a very important part of Space Weather. Modeling and monitoring of ionospheric variability is a major part of satellite communication, navigation and positioning systems. Total Electron Content (TEC), which is defined as the line integral of the electron density along a ray path, is one of the parameters to investigate the ionospheric variability. Dual-frequency GPS receivers, with their world wide availability and efficiency in TEC estimation, have become a major source of global and regional TEC modeling. When Global Ionospheric Maps (GIM) of International GPS Service (IGS) centers (http://iono.jpl.nasa.gov/gim.html) are investigated, it can be observed that regional ionosphere along the midlatitude regions can be modeled as a constant, linear or a quadratic surface. Globally, especially around the magnetic equator, the TEC surfaces resemble twisted and dispersed single centered or double centered Gaussian functions. Particle Swarm Optimization (PSO) proved itself as a fast converging and an effective optimization tool in various diverse fields. Yet, in order to apply this optimization technique into TEC modeling, the method has to be modified for higher efficiency and accuracy in extraction of geophysical parameters such as model parameters of TEC surfaces. In this study, a modified PSO (mPSO) method is applied to regional and global synthetic TEC surfaces. The synthetic surfaces that represent the trend and small scale variability of various ionospheric states are necessary to compare the performance of mPSO over number of iterations, accuracy in parameter estimation and overall surface reconstruction. The Cramer-Rao bounds for each surface type and model are also investigated and performance of mPSO are tested with respect to these bounds. For global models, the sample points that are used in optimization are obtained using IGS receiver network. For regional TEC models, regional networks such as Turkish National Permanent GPS Network (TNPGN

  6. Preliminary Investigation of Longitudinal Differences in TEC and Scintillation at Transition Latitudes

    DTIC Science & Technology

    1991-04-04

    AIR. j NO ABSOLUTE TEC. C: NEW SATELITE WINDOWS INSERTED. j - IAPEDRIVE PROBLEM. D: SOME DATA ON CHART NOT RECORDED ON TAPE. H = NPIB INTERFASE...PROBLEM. E: SOME DATA BROKEN UP. V 2 FLOPPY DISK/DRIVE PROBLEM. F: TAPE CHANGE. W - WRONG SATELITE WINDOWS. TOTAL HOURS OF ACTIVITY LEVEL 1:300 P - POWER...0 1 0 31 1 COMMENT’S: ADDITIONAL COMMENT’S. A: TAPE STOP * L1/L2 SCINTILLATION. B: GPS SYSTEM OFF THE AIR. O= N ABSOLUTE TEC. C: NEW SATELITE WINDOWS

  7. A regional ionospheric TEC mapping technique over China and adjacent areas on the basis of data assimilation

    NASA Astrophysics Data System (ADS)

    Aa, Ercha; Huang, Wengeng; Yu, Shimei; Liu, Siqing; Shi, Liqin; Gong, Jiancun; Chen, Yanhong; Shen, Hua

    2015-06-01

    In this paper, a regional total electron content (TEC) mapping technique over China and adjacent areas (70°E-140°E and 15°N-55°N) is developed on the basis of a Kalman filter data assimilation scheme driven by Global Navigation Satellite Systems (GNSS) data from the Crustal Movement Observation Network of China and International GNSS Service. The regional TEC maps can be generated accordingly with the spatial and temporal resolution being 1°×1° and 5 min, respectively. The accuracy and quality of the TEC mapping technique have been validated through the comparison with GNSS observations, the International Reference Ionosphere model values, the global ionosphere maps from Center for Orbit Determination of Europe, and the Massachusetts Institute of Technology Automated Processing of GPS TEC data from Madrigal database. The verification results indicate that great systematic improvements can be obtained when data are assimilated into the background model, which demonstrates the effectiveness of this technique in providing accurate regional specification of the ionospheric TEC over China and adjacent areas.

  8. Millimeter-Wave Polarimeters Using Kinetic Inductance Detectors for TolTEC and Beyond

    NASA Astrophysics Data System (ADS)

    Austermann, J. E.; Beall, J. A.; Bryan, S. A.; Dober, B.; Gao, J.; Hilton, G.; Hubmayr, J.; Mauskopf, P.; McKenney, C. M.; Simon, S. M.; Ullom, J. N.; Vissers, M. R.; Wilson, G. W.

    2018-05-01

    Microwave kinetic inductance detectors (MKIDs) provide a compelling path forward to the large-format polarimeter, imaging, and spectrometer arrays needed for next-generation experiments in millimeter-wave cosmology and astronomy. We describe the development of feedhorn-coupled MKID detectors for the TolTEC millimeter-wave imaging polarimeter being constructed for the 50-m Large Millimeter Telescope (LMT). Observations with TolTEC are planned to begin in early 2019. TolTEC will comprise ˜ 7000 polarization-sensitive MKIDs and will represent the first MKID arrays fabricated and deployed on monolithic 150 mm diameter silicon wafers—a critical step toward future large-scale experiments with over 10^5 detectors. TolTEC will operate in observational bands at 1.1, 1.4, and 2.0 mm and will use dichroic filters to define a physically independent focal plane for each passband, thus allowing the polarimeters to use simple, direct-absorption inductive structures that are impedance matched to incident radiation. This work is part of a larger program at NIST-Boulder to develop MKID-based detector technologies for use over a wide range of photon energies spanning millimeter-waves to X-rays. We present the detailed pixel layout and describe the methods, tools, and flexible design parameters that allow this solution to be optimized for use anywhere in the millimeter and sub-millimeter bands. We also present measurements of prototype devices operating in the 1.1 mm band and compare the observed optical performance to that predicted from models and simulations.

  9. SubTec-7 Gives New Technologies a Flight Test

    NASA Image and Video Library

    2017-12-08

    NASA successfully launched the SubTec-7 payload on a Black Brant IX suborbital sounding rocket at 5:45 a.m. EDT, May 16, from the NASA's Wallops Flight Facility. The payload flew to an altitude of about 154 miles before descending by parachute and landing in the Atlantic Ocean. SubTec-7 provided a flight test for more than 20 technologies to improve sounding rocket and spacecraft capabilities. Good data was received during the flight. The payload has been recovered. Credit: NASA/Wallops NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  10. Tec-kinase-mediated phosphorylation of fibroblast growth factor 2 is essential for unconventional secretion.

    PubMed

    Ebert, Antje D; Laussmann, Mareike; Wegehingel, Sabine; Kaderali, Lars; Erfle, Holger; Reichert, Jürgen; Lechner, Johannes; Beer, Hans-Dietmar; Pepperkok, Rainer; Nickel, Walter

    2010-06-01

    Fibroblast growth factor 2 (FGF2) is a potent mitogen that is exported from cells by an endoplasmic reticulum (ER)/Golgi-independent mechanism. Unconventional secretion of FGF2 occurs by direct translocation across plasma membranes, a process that depends on the phosphoinositide phosphatidylinositol 4,5-biphosphate (PI(4,5)P(2)) at the inner leaflet as well as heparan sulfate proteoglycans at the outer leaflet of plasma membranes; however, additional core and regulatory components of the FGF2 export machinery have remained elusive. Here, using a highly effective RNAi screening approach, we discovered Tec kinase as a novel factor involved in unconventional secretion of FGF2. Tec kinase does not affect FGF2 secretion by an indirect mechanism, but rather forms a heterodimeric complex with FGF2 resulting in phosphorylation of FGF2 at tyrosine 82, a post-translational modification shown to be essential for FGF2 membrane translocation to cell surfaces. Our findings suggest a crucial role for Tec kinase in regulating FGF2 secretion under various physiological conditions and, therefore, provide a new perspective for the development of a novel class of antiangiogenic drugs targeting the formation of the FGF2/Tec complex.

  11. Evaluation of long term solar activity effects on GPS derived TEC

    NASA Astrophysics Data System (ADS)

    Mansoori, Azad A.; Khan, Parvaiz A.; Ahmad, Rafi; Atulkar, Roshni; M, Aslam A.; Bhardwaj, Shivangi; Malvi, Bhupendra; Purohit, P. K.; Gwal, A. K.

    2016-10-01

    The solar activity hence the solar radiance follows a long term periodic variability with eleven years periodicity, known as solar cycle. This drives the long term variability of the ionosphere. In the present problem we investigate the long term behaviour of the ionosphere with the eleven year cyclic solar activity. Under the present study we characterize the ionospheric variability by Total Electron Content (TEC) using measurements made by Global Positioning System (GPS) and solar cycle variability by various solar activity indices. We make use of five solar activity indices viz. sunspot number (Rz), solar radio Flux (F10.7 cm), EUV Flux (26-34 nm), flare index and CME occurrences. The long term variability of these solar activity indices were then compared and correlated with the variability of ionospheric TEC, at a mid latitude station, Usuda (36.13N, 138.36E), of Japan, during the solar cycle 23 and ascending phase of cycle 24. From our study, we found that long term changes in the ionospheric TEC vary synchronously with corresponding changes in the solar activity indices. The correlation analysis shows that all the solar activity indices exhibit a very strong correlation with TEC (R =0.76 -0.99). Moreover the correlation between the two is stronger in the descending phase of the solar cycle. The correlation is found to be remarkably strongest during the deep minimum of the solar cycle 24 i.e. between 2007- 2009. Also we noticed a hysteresis effect exists with solar radio flux (F10.7 cm) and solar EUV flux (26-34 nm). This effect is absent with other parameters.

  12. Statistical analysis of ionospheric TEC anomalies before global M w ≥ 7.0 earthquakes using data of CODE GIM

    NASA Astrophysics Data System (ADS)

    Liu, Wenjing; Xu, Liang

    2017-07-01

    Based on Center of Orbit Determination in Europe (CODE) global ionospheric map (GIM) data, a statistical analysis of local total electron content (TEC) anomalies before 121 low-depth ( D ≤ 100 km) strong ( M w ≥ 7.0) earthquakes has been made using the sliding median differential calculation method combining with a new approach of image processing technique. The results show that significant local TEC anomalies could be observed 0-6 days before 80 earthquakes, about 66.1% out of the total. The positive anomalies occur more often than negative ones. For 26 cases, both positive and negative anomalies are observed before the shock. The pre-earthquake TEC anomalies show local time recurrence for 38 earthquakes, which occur around the same local time on different days. The local time distribution of the pre-earthquake TEC anomalies mainly concentrates between 19 and 06 LT, roughly from the sunset to sunrise. Most of the pre-earthquake TEC anomalies do not locate above the epicenter but shift to the south. The pre-earthquake TEC anomalies could be extracted near the magnetic conjugate point of the epicenter for 40 events, which is 50% out of the total 80 cases with significant local TEC anomalies. In general, the signs of the anomalies around epicenter and its conjugate point are the same, but the abnormal magnitude and lasting time are not.

  13. Anomalous variation in GPS based TEC measurements prior to the 30 September 2009 Sumatra Earthquake

    NASA Astrophysics Data System (ADS)

    Karia, Sheetal; Pathak, Kamlesh

    This paper investigates the features of pre-earthquake ionospheric anomalies in the total elec-tron content (TEC) data obtained on the basis of regular GPS observations from the GPS receiver at SVNIT Surat (21.16 N, 72.78 E Geog) located at the northern crest of equatorial anomaly region. The data has been analysed for 5 different earthquakes that occurred during 2009 in India and its neighbouring regions. Our observation shows that for the cases of the earthquake, in which the preparation area lies between the crests of the equatorial anomaly close to the geomagnetic equator the enhancement in TEC was followed by a depletion in TEC on the day of earthquake, which may be connected to the equatorial anomaly shape distortions. For the analysis of the ionospheric effects of one of such case-the 30 September 2009 Sumatra earthquake, Global Ionospheric Maps of TEC were used. The possible influence of the earth-quake preparation processes on the main low-latitude ionosphere peculiarity—the equatorial anomaly—is discussed.

  14. TEC Longitude Difference Using GIMS and the IRI Model

    NASA Astrophysics Data System (ADS)

    Natali, Maria Paula; Meza, Amalia Margarita; Mendoza, Gastón

    2016-07-01

    The main geomagnetic field declination has a global distribution with positive and negative values showing maximum east-west differences over North America and Oceania and minimum differences over America and Asia. Several authors study one or more of these regions using TEC data derived from GNSS observations to describe variations in TEC. They reported a pronounced longitudinal variation respect to zero magnetic declination. One of the important factors that cause the longitude difference at mid-latitude is a combined effect of the longitude variations of magnetic declination and the variations of the zonal thermospheric winds with local time. We propose to study this effect using Global Ionospheric Maps (GIMs) and the respective TEC values generated from the International Reference Ionospheric (IRI) model, during a solar cycle, applying Principal Component Analysis (PCA). Our works is focused over different local times and regions at mid-latitude. PCA involves a mathematical procedure that transforms a number of correlated variables into a number of uncorrelated variables using the data itself. The spatial structure of the ionosphere variability and its temporal evolution, together are called modes, and there are ordered according to their percentage of the variability of data from highest to lowest. In this analysis the first mode has more than the 90 % of the variability, representing the nominal behavior of the ionosphere, and the second and third modes are the more important for our analysis, because they show the strong longitudinal variation in the different regions using either GIMs or the IRI model.

  15. Anomalous Variation in GPS TEC, Land and Ocean Parameters Prior to 3 Earthquakes

    NASA Astrophysics Data System (ADS)

    Yadav, Kunvar; Karia, Sheetal P.; Pathak, Kamlesh N.

    2016-02-01

    The present study reports the analysis of GPS TEC prior to 3 earthquakes ( M > 6.0). The earthquakes are: (1) Loyalty Island (22°36'S, 170°54'E) on 19 January 2009 ( M = 6.6), (2) Samoa Island (15°29'S, 172°5'W) on 30 August 2009 ( M = 6.6), and (3) Tohoku (38°19'N, 142°22'E) on 11 March 2011 ( M = 9.0). In an effort to search for a precursory signature we analysed the land and ocean parameters prior to the earthquakes, namely SLHF (Land) and SST (Ocean). The GPS TEC data indicate an anomalous behaviour from 1-13 days prior to earthquakes. The main purpose of this study was to explore and demonstrate the possibility of any changes in TEC, SST, and SLHF before, during and after the earthquakes which occurred near or beneath an ocean. This study may lead to better understanding of response of land, ocean, and ionosphere parameters prior to seismic activities.

  16. Regional TEC dynamic modeling based on Slepian functions

    NASA Astrophysics Data System (ADS)

    Sharifi, Mohammad Ali; Farzaneh, Saeed

    2015-09-01

    In this work, the three-dimensional state of the ionosphere has been estimated by integrating the spherical Slepian harmonic function and Kalman filter. The spherical Slepian harmonic functions have been used to establish the observation equations because of their properties in local modeling. Spherical harmonics are poor choices to represent or analyze geophysical processes without perfect global coverage but the Slepian functions afford spatial and spectral selectivity. The Kalman filter has been utilized to perform the parameter estimation due to its suitable properties in processing the GPS measurements in the real-time mode. The proposed model has been applied to the real data obtained from the ground-based GPS observations across some portion of the IGS network in Europe. Results have been compared with the estimated TECs by the CODE, ESA, IGS centers and IRI-2012 model. The results indicated that the proposed model which takes advantage of the Slepian basis and Kalman filter is efficient and allows for the generation of the near-real-time regional TEC map.

  17. AzTEC millimetre survey of the COSMOS field - I. Data reduction and source catalogue

    NASA Astrophysics Data System (ADS)

    Scott, K. S.; Austermann, J. E.; Perera, T. A.; Wilson, G. W.; Aretxaga, I.; Bock, J. J.; Hughes, D. H.; Kang, Y.; Kim, S.; Mauskopf, P. D.; Sanders, D. B.; Scoville, N.; Yun, M. S.

    2008-04-01

    We present a 1.1 mm wavelength imaging survey covering 0.3 deg2 in the COSMOS field. These data, obtained with the AzTEC continuum camera on the James Clerk Maxwell Telescope, were centred on a prominent large-scale structure overdensity which includes a rich X-ray cluster at z ~ 0.73. A total of 50 mm-galaxy candidates, with a significance ranging from 3.5 to 8.5σ, are extracted from the central 0.15 deg2 area which has a uniform sensitivity of ~1.3 mJybeam-1. 16 sources are detected with S/N >= 4.5, where the expected false-detection rate is zero, of which a surprisingly large number (9) have intrinsic (deboosted) fluxes >=5 mJy at 1.1 mm. Assuming the emission is dominated by radiation from dust, heated by a massive population of young, optically obscured stars, then these bright AzTEC sources have far-infrared luminosities >6 × 1012Lsolar and star formation rates >1100Msolaryr-1. Two of these nine bright AzTEC sources are found towards the extreme peripheral region of the X-ray cluster, whilst the remainder are distributed across the larger scale overdensity. We describe the AzTEC data reduction pipeline, the source-extraction algorithm, and the characterization of the source catalogue, including the completeness, flux deboosting correction, false-detection rate and the source positional uncertainty, through an extensive set of Monte Carlo simulations. We conclude with a preliminary comparison, via a stacked analysis, of the overlapping MIPS 24-μm data and radio data with this AzTEC map of the COSMOS field.

  18. Review of variations in Mw < 7 earthquake motions on position and tec (Mw = 6.5 aegean sea earthquake sample)

    NASA Astrophysics Data System (ADS)

    Yildirim, O.; Inyurt, S.; Mekik, C.

    2015-10-01

    Turkey is a country located in Middle Latitude zone and in which tectonic activity is intensive. Lastly, an earthquake of magnitude 6.5Mw occurred at Aegean Sea offshore on date 24 May 2014 at 12:25 UTC and it lasted approximately 40 s. The said earthquake was felt also in Greece, Romania and Bulgaria in addition to Turkey. In recent years seismic origin ionospheric anomaly detection studies have been done with TEC (Total Electron Contents) generated from GNSS (Global Navigation Satellite System) signals and the findings obtained have been revealed. In this study, TEC and positional variations have been examined seperately regarding the earthquake which occurred in the Aegean Sea. Then The correlation of the said ionospheric variation with the positional variation has been investigated. For this purpose, total fifteen stations have been used among which the data of four numbers of CORS-TR stations in the seismic zone (AYVL, CANA, IPSA, YENC) and IGS and EUREF stations are used. The ionospheric and positional variations of AYVL, CANA, IPSA and YENC stations have been examined by Bernese 5.0v software. When the (PPP-TEC) values produced as result of the analysis are examined, it has been understood that in the four stations located in Turkey, three days before the earthquake at 08:00 and 10:00 UTC, the TEC values were approximately 4 TECU above the upper limit TEC value. Still in the same stations, one day before the earthquake at 06:00, 08:00 and 10:00 UTC, it is being shown that the TEC values were approximately 5 TECU below the lower limit TEC value. On the other hand, the GIM-TEC values published by the CODE center have been examined. Still in all stations, it has been observed that three days before the earthquake the TEC values in the time portions of 08:00 and 10:00 UTC were approximately 2 TECU above, one day before the earthquake at 06:00, 08:00 and 10:00 UTC, the TEC values were approximately 4 TECU below the lower limit TEC value. Again, by using the same

  19. An Analysis on the TEC Variability and Ionospheric Scintillation at Los Alamos, New Mexico Derived from FORTE-Received LAPP Signals

    NASA Astrophysics Data System (ADS)

    Huang, Z.; Roussel-Dupre, R.

    2003-12-01

    The total electron content (TEC) of ionosphere and its electron density irregularities (scintillation) have effects of degradation and disruption on radio signals passed between ground stations and orbiting man-made satellites. With the rapid increase in operational reliance on UHF/VHF satellite communication, it is desirable to obtain understandings of ionosphere TEC variability and scintillation characteristics to improve our ability of predicting satellite communication outages. In this work, data collected from FORTE satellite received LAPP (Los Alamos Portable Pulser) signals during 1998-2002 are used to derive TEC and ionospheric scintillation index at Los Alamos, New Mexico. To characterize in-situ TEC variability at Los Alamos, the FORTE-LAPP derived TECs are analyzed against diurnal, seasonal, solar activity, magnetic storm, and stratospheric warming. The results are also compared with the TEC estimates from the Los Alamos ionospheric transfer function (ITF) implemented with the global ionospheric models (IRI, PIM), and GPS -derived TEC maps. The FORTE-LAPP signals are also analyzed against two important measures of the effect of scintillation on broadband signals, the mean time delay and the time delay jitter. The results are used to examine coherence frequency bandwidth and compared with the predictions from a global scintillation model (WBMOD). The FORTE-LAPP analyzed and WBMOD predicted scintillation characteristics are used to investigate temporal and seasonal behavior of scintillation at Los Alamos.

  20. Observed TEC Anomalies by GNSS Sites Preceding the Aegean Sea Earthquake of 2014

    NASA Astrophysics Data System (ADS)

    Ulukavak, Mustafa; Yal&ccedul; ınkaya, Mualla

    2016-11-01

    In recent years, Total Electron Content (TEC) data, obtained from Global Navigation Satellites Systems (GNSS) receivers, has been widely used to detect seismo-ionospheric anomalies. In this study, Global Positioning System - Total Electron Content (GPS-TEC) data were used to investigate ionospheric abnormal behaviors prior to the 2014 Aegean Sea earthquake (40.305°N 25.453°E, 24 May 2014, 09:25:03 UT, Mw:6.9). The data obtained from three Continuously Operating Reference Stations in Turkey (CORS-TR) and two International GNSS Service (IGS) sites near the epicenter of the earthquake is used to detect ionospheric anomalies before the earthquake. Solar activity index (F10.7) and geomagnetic activity index (Dst), which are both related to space weather conditions, were used to analyze these pre-earthquake ionospheric anomalies. An examination of these indices indicated high solar activity between May 8 and 15, 2014. The first significant increase (positive anomalies) in Vertical Total Electron Content (VTEC) was detected on May 14, 2014 or 10 days before the earthquake. This positive anomaly can be attributed to the high solar activity. The indices do not imply high solar or geomagnetic activity after May 15, 2014. Abnormal ionospheric TEC changes (negative anomaly) were observed at all stations one day before the earthquake. These changes were lower than the lower bound by approximately 10-20 TEC unit (TECU), and may be considered as the ionospheric precursor of the 2014 Aegean Sea earthquake

  1. Performance evaluation of GNSS-TEC estimation techniques at the grid point in middle and low latitudes during different geomagnetic conditions

    NASA Astrophysics Data System (ADS)

    Abe, O. E.; Otero Villamide, X.; Paparini, C.; Radicella, S. M.; Nava, B.; Rodríguez-Bouza, M.

    2017-04-01

    Global Navigation Satellite Systems (GNSS) have become a powerful tool use in surveying and mapping, air and maritime navigation, ionospheric/space weather research and other applications. However, in some cases, its maximum efficiency could not be attained due to some uncorrelated errors associated with the system measurements, which is caused mainly by the dispersive nature of the ionosphere. Ionosphere has been represented using the total number of electrons along the signal path at a particular height known as Total Electron Content (TEC). However, there are many methods to estimate TEC but the outputs are not uniform, which could be due to the peculiarity in characterizing the biases inside the observables (measurements), and sometimes could be associated to the influence of mapping function. The errors in TEC estimation could lead to wrong conclusion and this could be more critical in case of safety-of-life application. This work investigated the performance of Ciraolo's and Gopi's GNSS-TEC calibration techniques, during 5 geomagnetic quiet and disturbed conditions in the month of October 2013, at the grid points located in low and middle latitudes. The data used are obtained from the GNSS ground-based receivers located at Borriana in Spain (40°N, 0°E; mid latitude) and Accra in Ghana (5.50°N, -0.20°E; low latitude). The results of the calibrated TEC are compared with the TEC obtained from European Geostationary Navigation Overlay System Processing Set (EGNOS PS) TEC algorithm, which is considered as a reference data. The TEC derived from Global Ionospheric Maps (GIM) through International GNSS service (IGS) was also examined at the same grid points. The results obtained in this work showed that Ciraolo's calibration technique (a calibration technique based on carrier-phase measurements only) estimates TEC better at middle latitude in comparison to Gopi's technique (a calibration technique based on code and carrier-phase measurements). At the same time

  2. Investigating the performance of neural network backpropagation algorithms for TEC estimations using South African GPS data

    NASA Astrophysics Data System (ADS)

    Habarulema, J. B.; McKinnell, L.-A.

    2012-05-01

    In this work, results obtained by investigating the application of different neural network backpropagation training algorithms are presented. This was done to assess the performance accuracy of each training algorithm in total electron content (TEC) estimations using identical datasets in models development and verification processes. Investigated training algorithms are standard backpropagation (SBP), backpropagation with weight delay (BPWD), backpropagation with momentum (BPM) term, backpropagation with chunkwise weight update (BPC) and backpropagation for batch (BPB) training. These five algorithms are inbuilt functions within the Stuttgart Neural Network Simulator (SNNS) and the main objective was to find out the training algorithm that generates the minimum error between the TEC derived from Global Positioning System (GPS) observations and the modelled TEC data. Another investigated algorithm is the MatLab based Levenberg-Marquardt backpropagation (L-MBP), which achieves convergence after the least number of iterations during training. In this paper, neural network (NN) models were developed using hourly TEC data (for 8 years: 2000-2007) derived from GPS observations over a receiver station located at Sutherland (SUTH) (32.38° S, 20.81° E), South Africa. Verification of the NN models for all algorithms considered was performed on both "seen" and "unseen" data. Hourly TEC values over SUTH for 2003 formed the "seen" dataset. The "unseen" dataset consisted of hourly TEC data for 2002 and 2008 over Cape Town (CPTN) (33.95° S, 18.47° E) and SUTH, respectively. The models' verification showed that all algorithms investigated provide comparable results statistically, but differ significantly in terms of time required to achieve convergence during input-output data training/learning. This paper therefore provides a guide to neural network users for choosing appropriate algorithms based on the availability of computation capabilities used for research.

  3. The National Network forTechnology Entrepreneurship and Commercialization (N2TEC): Bringing New Technologies to Market

    NASA Astrophysics Data System (ADS)

    Allen, Kathleen

    2003-03-01

    N2TEC, the National Network for Technology Entrepreneurship and Commercialization, is a National Science Foundation "Partnerships for Innovation" initiative designed to raise the level of innovation and technology commercialization in colleges, universities, and communities across the nation. N2TEC is creating a network of people and institutions, and a set of technology tools that will facilitate the pooling of resources and knowledge and enable faculty and students to share those resources and collaborate without regard to geographic boundaries. N2TEC will become the backbone by which educational institutions across the nation can move their technologies into new venture startups. The ultimate goal is to create new wealth and strengthen local, regional and national economies.

  4. High Temporal and Spatial Resolution Global GPS TEC Observations of the 2015 St. Patrick Day Storm

    NASA Astrophysics Data System (ADS)

    Vierinen, J.

    2015-12-01

    High spatiotemperal resolution global GPS TEC measurements of the 2015 St. Patrick's day storm are presented. The high resolution data is useful, as it clearly shows the high latitude convection patterns, the equatorward progression of the auroral region, the tongue of ionization, as well as the increased electron density in the equatorial anomaly region. The measurements are compared with high power large aperture radar and passive radar measurements of coherent and incoherent scatter at Millstone Hill. Regions of fast convection identified in the GPS TEC data are found to coincide with coherent scatter in both radar data. Convection velocities determined from GPS TEC are compared with those obtained from incoherent scatter radar measurements.

  5. Comparison of the Fenwal Amicus and Fresenius Com.Tec cell separators for autologous peripheral blood progenitor cell collection.

    PubMed

    Altuntas, Fevzi; Kocyigit, Ismail; Ozturk, Ahmet; Kaynar, Leylagul; Sari, Ismail; Oztekin, Mehmet; Solmaz, Musa; Eser, Bulent; Cetin, Mustafa; Unal, Ali

    2007-04-01

    Peripheral blood progenitor cells (PBPC) are commonly used as a stem cell source for autologous transplantation. This study was undertaken to evaluate blood cell separators with respect to separation results and content of the harvest. Forty autologous PBPC collections in patients with hematological malignancies were performed with either the Amicus or the COM.TEC cell separators. The median product volume was lower with the Amicus compared to the COM.TEC (125 mL vs. 300 mL; p < 0.001). There was no statistically significant difference in the median number of CD34+ cell/kg in product between the Amicus and the COM.TEC (3.0 x 10(6) vs. 4.1 x 10(6); p = 0.129). There was a statistically higher mean volume of ACD used in collections on the Amicus compared to the COM.TEC (1040 +/- 241 mL vs. 868 +/- 176 mL; p = 0.019). There was a statistical difference in platelet (PLT) contamination of the products between the Amicus and the COM.TEC (0.3 x 10(11) vs. 1.1 x 10(11); p < 0.001). The median % decrease in PB PLT count was statistically higher in the COM.TEC compared to the Amicus instruments (18.5% vs. 9.5%; p = 0.028). In conclusion, both instruments collected PBPCs efficiently. However, Amicus has the advantage of lower PLT contamination in the product, and less decrease in PB platelet count with lower product volume in autologous setting.

  6. Galaxy evolution at high-redshift: Millimeter-wavelength surveys with the AzTEC camera

    NASA Astrophysics Data System (ADS)

    Scott, Kimberly S.

    Galaxies detected by their thermal dust emission at submillimeter (submm) and millimeter (mm) wavelengths comprise a population of massive, intensely star-forming systems in the early Universe. These "submm/mm- galaxies", or SMGs, likely represent an important phase in the assembly and/or evolution of massive galaxies and are thought to be the progenitors of massive elliptical galaxies. While their projected number density as a function of source brightness provides key constraints on models of galaxy evolution, SMG surveys carried out over the past twelve years with the first generation of submm/mm-wavelength cameras have not imaged a large enough area to sufficient depths to provide the statistical power needed to discriminate between competing galaxy evolution scenarios. In this dissertation, we present the results from SMG surveys carried out over the past four years using the new sensitive mm-wavelength camera AzTEC. With the improved mapping speed of the AzTEC camera combined with dedicated telescope time devoted to deep, large-area extragalactic surveys, we have tripled both the area surveyed towards blank- fields (that is, regions with no known galaxy over-densities) at submm/mm wavelengths and the total number of detected SMGs. Here, we describe the properties and performance of the AzTEC instrument while operating on the James Clerk Maxwell Telescope (JCMT) and the Atacama Submillimeter Telescope Experiment (ASTE). We then present the results from two of the blank-field regions imaged with AzTEC: the JCMT/COSMOS field, which we discovered is over- dense in the number of very bright SMGs, and the ASTE survey of the Great Observatories Origins Deep-South field, which represents one of the deepest surveys ever carried out at submm/mm wavelengths. Finally, we combine the results from all of the blank-fields imaged with AzTEC while operating on the JCMT and the ASTE to calculate the most accurate measurements to date of the SMG number counts.

  7. Variation of GPS-TEC in a low latitude Indian region during the year 2012 and 2013

    NASA Astrophysics Data System (ADS)

    Patel, Nilesh C.; Karia, Sheetal P.; Pathak, Kamlesh N.

    2018-05-01

    The paper is based on the ionospheric variations in terms of vertical total electron content (VTEC) for the period from January 2012 to December 2013 based on the analysis of dual frequency signals from the Global Positioning System (GPS) satellites recorded at ground stations Surat (21.16°N, 72.78°E Geog.), situated under the northern crest of the equatorial ionization anomaly region (EIA) and other three International GNSS Service (IGS) stations Bangalore (13.02°N, 77.57°E Geog.), Hyderabad (17.25°N, 78.30°E Geog.), and Lucknow (26.91°N, 80.95°E Geog.) in India. We describe the diurnal and seasonal characteristics. It was observed that GPS-TEC reaches its maximum value between 12:00 and 16:00 IST. Further, Seasonal variations of GPS-TEC is categorized into four seasons, i.e., March equinox (February, March, and April), June solstice (May, June, and July), September equinox (August, September, and October) and December solstice (November, December and January). The forenoon rate of production in Lucknow (beyond EIA crest) is faster than Bangalore, Hyderabad and Surat station. It is found that September equinox shows GPS-TEC slightly higher than the March equinox, followed by June solstice and the lowest GPS-TEC are in winter solstice at four stations. The equinoctial asymmetry clearly observed in the current study. Also GPS-TEC shows a semiannual variation.

  8. The mapping of ionospheric TEC for central Russian and European regions on the base of GPS and GLONASS measurements

    NASA Astrophysics Data System (ADS)

    Shagimuratov, Irk; Cherniak, Iurii; Zakharenkova, Irina; Ephishov, Ivan; Krankowski, Andrzej; Radievsky, Alexander

    2014-05-01

    The total electron content (TEC) is a key parameter not only for space radio communication but also for addressing the fundamental problems of the ionosphere physics and near Earth space. Currently, the main sources of information on the TEC in the global scale are GNSS signals measurements. The spatial-temporal behavior of the ionosphere can be most effectively analyzed using TEC maps. To date, global IGS global ionospheric maps with a resolution of 2.5 degree in latitude and 5 in longitude and a time resolution of 2 h are most widely used. To study the detailed structure of the ionospheric gradients and rapid process as well as for precise positioning task it is necessary to use more precise regional TEC maps. The Regional TEC maps are currently constructed by different research groups for different regions: USA, Europe, Japan etc. The West Department of IZMIRAN research group is a one in Russia who works on the task of regional ionosphere mapping since 2000. It was developed the methodology for obtaining information on the spatial TEC distribution, TEC maps of the ionosphere on the basis of the algorithm for multi-station processing of GNSS observations. Using a set of algorithms and programs, regional TEC maps with a spatial resolution of 1° and a time resolution up to 15 min can be produced. Here is developed the approach to establish the regular online internet service for regional ionosphere mapping of the Western Russia and Eastern Europe. Nowadays the development of GLONASS navigation system is completely finished and it consists of a constellation of more than 24 satellites. It is good perspective for investigations of the ionosphere structure and dynamics on the base of the simultaneous observations of GPS and GLONASS systems. The GLONASS satellites have the inclination about 64 degrees as against GPS satellites with 56. So the GLONASS provides opportunity to study the high latitude ionosphere. The different scale electron density irregularities

  9. Medium Calcium Concentration Determines Keratin Intermediate Filament Density and Distribution in Immortalized Cultured Thymic Epithelial Cells (TECs)

    NASA Astrophysics Data System (ADS)

    Sands, Sandra S.; Meek, William D.; Hayashi, Jun; Ketchum, Robert J.

    2005-08-01

    Isolation and culture of thymic epithelial cells (TECs) using conventional primary tissue culture techniques under conditions employing supplemented low calcium medium yielded an immortalized cell line derived from the LDA rat (Lewis [Rt1l] cross DA [Rt1a]) that could be manipulated in vitro. Thymi were harvested from 4 5-day-old neonates, enzymically digested using collagenase (1 mg/ml, 37°C, 1 h) and cultured in low calcium WAJC404A medium containing cholera toxin (20 ng/ml), dexamethasone (10 nM), epidermal growth factor (10 ng/ml), insulin (10 [mu]g/ml), transferrin (10 [mu]g/ml), 2% calf serum, 2.5% Dulbecco's Modified Eagle's Medium (DMEM), and 1% antibiotic/antimycotic. TECs cultured in low calcium displayed round to spindle-shaped morphology, distinct intercellular spaces (even at confluence), and dense reticular-like keratin patterns. In high calcium (0.188 mM), TECs formed cobblestone-like confluent monolayers that were resistant to trypsinization (0.05%) and displayed keratin intermediate filaments concentrated at desmosomal junctions between contiguous cells. Changes in cultured TEC morphology were quantified by an analysis of desmosome/membrane relationships in high and low calcium media. Desmosomes were significantly increased in the high calcium medium. These studies may have value when considering the growth conditions of cultured primary cell lines like TECs.

  10. Validation of foF2 and TEC Modeling During Geomagnetic Disturbed Times: Preliminary Outcomes of International Forum for Space Weather Modeling Capabilities Assessment

    NASA Astrophysics Data System (ADS)

    Shim, J. S.; Tsagouri, I.; Goncharenko, L. P.; Kuznetsova, M. M.

    2017-12-01

    To address challenges of assessment of space weather modeling capabilities, the CCMC (Community Coordinated Modeling Center) is leading the newly established "International Forum for Space Weather Modeling Capabilities Assessment." This presentation will focus on preliminary outcomes of the International Forum on validation of modeled foF2 and TEC during geomagnetic storms. We investigate the ionospheric response to 2013 Mar. geomagnetic storm event using ionosonde and GPS TEC observations in North American and European sectors. To quantify storm impacts on foF2 and TEC, we first quantify quiet-time variations of foF2 and TEC (e.g., the median and the average of the five quietest days for the 30 days during quiet conditions). It appears that the quiet time variation of foF2 and TEC are about 10% and 20-30%, respectively. Therefore, to quantify storm impact, we focus on foF2 and TEC changes during the storm main phase larger than 20% and 50%, respectively, compared to 30-day median. We find that in European sector, both foF2 and TEC response to the storm are mainly positive phase with foF2 increase of up to 100% and TEC increase of 150%. In North America sector, however, foF2 shows negative effects (up to about 50% decrease), while TEC shows positive response (the largest increase is about 200%). To assess modeling capability of reproducing the changes of foF2 and TEC due to the storm, we use various model simulations, which are obtained from empirical, physics-based, and data assimilation models. The performance of each model depends on the selected metrics, therefore, only one metrics is not enough to evaluate the models' predictive capabilities in capturing the storm impact. The performance of the model also varies with latitude and longitude.

  11. AzTEC 1.1 mm OBSERVATIONS OF THE MBM12 MOLECULAR CLOUD

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

    Kim, M. J.; Kim, S.; Youn, S.

    2012-02-10

    We present 1.1 mm observations of the dust continuum emission from the MBM12 high-latitude molecular cloud observed with the Astronomical Thermal Emission Camera (AzTEC) mounted on the James Clerk Maxwell Telescope on Mauna Kea, Hawaii. We surveyed 6.34 deg{sup 2} centered on MBM12, making this the largest area that has ever been surveyed in this region with submillimeter and millimeter telescopes. Eight secure individual sources were detected with a signal-to-noise ratio of over 4.4. These eight AzTEC sources can be considered to be real astronomical objects compared to the other candidates based on calculations of the false detection rate. Themore » distribution of the detected 1.1 mm sources or compact 1.1 mm peaks is spatially anti-correlated with that of the 100 {mu}m emission and the {sup 12}CO emission. We detected the 1.1 mm dust continuum emitting sources associated with two classical T Tauri stars, LkH{alpha}262 and LkH{alpha}264. Observations of spectral energy distributions (SEDs) indicate that LkH{alpha}262 is likely to be Class II (pre-main-sequence star), but there are also indications that it could be a late Class I (protostar). A flared disk and a bipolar cavity in the models of Class I sources lead to more complicated SEDs. From the present AzTEC observations of the MBM12 region, it appears that other sources detected with AzTEC are likely to be extragalactic and located behind MBM12. Some of these have radio counterparts and their star formation rates are derived from a fit of the SEDs to the photometric evolution of galaxies in which the effects of a dusty interstellar medium have been included.« less

  12. The Role of ESA TEC-QTE in the ISS Safety Process

    NASA Astrophysics Data System (ADS)

    Orlandi, M.; Rohr, T.; Stienstra, M. H.; Semprimoschnig, C.

    2013-09-01

    On the 17th of July 2000, the Materials and Processes Reciprocal Agreement was signed between NASA and ESA to define the process for selection and certification of materials used in the Space Shuttle and the International Space Station. Consecutively, on the 20th of June 2003 this agreement was extended to the Automated Transport Vehicle (ATV). It is therefore the responsibility of ESA TEC-QTE, the Materials Space Evaluation and Radiation Effects section, part of the Product Assurance and Safety Department, to ensure that all materials, parts and processes of each of the ISS payloads not only function as required but also do not pose a risk to the safety of the crew members. In this context, TEC-QTE provides qualified expertise to support the ESA Flight Safety Review and assesses safety aspects related to manned projects (materials properties, fluid system compatibility, fungus resistance). This is supported by the Materials Space Evaluation and Radiation Effects section's Materials and Electrical Components laboratory having at its disposition a range of facilities designed to perform environmental effects testing of which off-gassing tests according to ECSS-Q-ST-70-29C (equivalent to NASA STD 6001 test 7) and outgassing tests according to ECSS-Q-ST-70-02C (equivalent to ASTM-E-595). The ESA facility to perform flammability tests according to ECSS-Q-ST-70-21A (equivalent to NASA STD 6001 test1) was moved to Astrium Bremen.TEC-QTE is in charge of reviewing and approving, via RFA or MUA , all materials that do not meet safety requirements as well as COTS or CAM (black boxes) equipment.The safety process ends with the issue of the Materials Certification of the reviewed payload hardware that shows compliance with the relevant materials and processes requirements and standards.In addition to the safety related activities for the ISS, specialised TEC-QTE personnel provide measurements of the air quality inside the ATV and assess whether the toxicity index is within

  13. Statistical seismo-ionospheric precursors of M7.0+ earthquakes in Circum-Pacific seismic belt by GPS TEC measurements

    NASA Astrophysics Data System (ADS)

    Li, Wang; Yue, Jianping; Guo, Jinyun; Yang, Yang; Zou, Bin; Shen, Yi; Zhang, Kefei

    2018-03-01

    The Circum-Pacific seismic belt is the region heavily affected by earthquakes in the world. The relationship between earthquake (e.g., the geographic location, occurrence time, magnitude, and focal depth) and ionospheric anomalies in the belt was investigated using 100 M7.0+ earthquakes during 2006-2015. The ground-based GPS measurements and global ionosphere map (GIM) data were used for the analyses of the ionospheric variations preceding the earthquakes. The results indicated that the occurrence rate of total electron content (TEC) anomalies was proportional to the magnitude and inversely proportional to the focal depth to a certain degree, and the occurrence frequency of anomalies had a rising trend with the days getting close to the main shock. The occurrence rate of TEC anomalies in the Southern hemisphere was larger than that in the Northern hemisphere. Besides, the spatial characteristics of TEC anomalies showed that the anomalies in low-middle latitudes did not coincide with the epicenter, sometimes the anomalies were also observed in the corresponding conjugated region. However, the TEC anomalies in the high latitude usually appeared around the epicenter and within the seismogenic zone while no TEC anomalies appeared in the conjugated area. These results may have potential applications to the earthquake prediction in the Circum-Pacific seismic belt.

  14. PCA and vTEC climatology at midnight over mid-latitude regions

    NASA Astrophysics Data System (ADS)

    Natali, M. P.; Meza, A.

    2017-12-01

    The effect of the thermospheric vertical neutral wind on vertical total electron content (vTEC) variations including longitudinal anomaly, remaining winter anomaly, mid-latitude summer night anomaly, and semiannual anomaly is studied at mid-latitude regions around zero magnetic declination at midnight during high solar activity. By using the principal component analysis (PCA) numerical technique, this work studies the spatial and temporal variations of the ionosphere at midnight over mid-latitude regions during 2000-2002. PCA is applied to a time series of global vTEC maps produced by the International Global Navigation Satellite System (GNSS) Service. Four regions were studied in particular, each located at mid-latitude and approximately centered at zero magnetic declination, with two in the northern hemisphere and two in southern hemisphere, and all are located near and far from geomagnetic poles in each case. This technique provides an effective method to analyze the main ionospheric variabilities at mid-latitudes. PCA is also applied to the vTEC computed using the International Reference Ionosphere (IRI) 2012 model, to analyze the capability of this model to represent ionospheric variabilities at mid-latitude. Also, the Horizontal Wind Model 2007 (HWM07) is used to improve our climatology interpretation, by analyzing the relationship between vTEC and thermospheric wind, both quantitatively and qualitatively. At midnight, the behavior of mean vTEC values strongly responds to vertical wind variation, experiencing a decrease of about 10-15% with the action of the positive vertical component of the field-aligned neutral wind lasting for 2 h in all regions except for Oceania. Notable results include: a significant increase toward higher latitudes during summer in the South America and Asia regions, associated with the mid-latitude summer night anomaly, and an increase toward higher latitudes in winter in the North America and Oceania regions, highlighting the

  15. An Ionospheric Response to the 2013 Moore EF5 Tornad, Detected By High-Resolution GPS-TEC Observations

    NASA Astrophysics Data System (ADS)

    Kubota, M.; Nishioka, M.; Tsugawa, T.; Ishii, M.

    2014-12-01

    We observed clear concentric waves and short-period oscillations in the ionosphere after the EF5 tornado hit Moore, Oklahoma, USA, on 20 May 2013 using a dense wide-coverage ionospheric total electron content (TEC) observation in North America. These concentric waves were non-dispersive waves with a horizontal wavelength of ~120 km and a period of ~13 minutes. They were observed for more than seven hours throughout North America. TEC oscillations with a period of ~4 minutes were also observed in the south of Moore for more than eight hours. Comparison between the TEC observation and the infrared cloud image from the GOES satellite indicates that the concentric waves were caused by supercells rather than the tornados themselves. Backward ray-tracing analysis suggests that the leaking of atmospheric waves in a thermal duct excited AGWs in the ionosphere. The short-period TEC oscillation could be explained by the acoustic resonance triggered by strong long-lasting supercells. This observational result provides the first clear evidence of a severe meteorological event causing atmospheric waves propagating upward in the upper atmosphere and reaching the ionosphere.

  16. Early Science with the Large Millimeter Telescope: CO and [C II] Emission in the z = 4.3 AzTEC J095942.9+022938 (COSMOS AzTEC-1)

    NASA Astrophysics Data System (ADS)

    Yun, Min S.; Aretxaga, I.; Gurwell, M. A.; Hughes, D. H.; Montaña, A.; Narayanan, G.; Rosa-González, D.; Sánchez-Argüelles, D.; Schloerb, F. P.; Snell, R. L.; Vega, O.; Wilson, G. W.; Zeballos, M.; Chavez, M.; Cybulski, R.; Díaz-Santos, T.; De La Luz, V.; Erickson, N.; Ferrusca, D.; Gim, H. B.; Heyer, M. H.; Iono, D.; Pope, A.; Rogstad, S. M.; Scott, K. S.; Souccar, K.; Terlevich, E.; Terlevich, R.; Wilner, D.; Zavala, J. A.

    2015-12-01

    Measuring redshifted CO line emission is an unambiguous method for obtaining an accurate redshift and total cold gas content of optically faint, dusty starburst systems. Here, we report the first successful spectroscopic redshift determination of AzTEC J095942.9+022938 (`COSMOS AzTEC-1'), the brightest 1.1 mm continuum source found in the AzTEC/James Clerk Maxwell Telescope survey (Scott et al.), through a clear detection of the redshifted CO (4-3) and CO (5-4) lines using the Redshift Search Receiver on the Large Millimeter Telescope. The CO redshift of z = 4.3420 ± 0.0004 is confirmed by the detection of the redshifted 158 μm [C II] line using the Submillimeter Array. The new redshift and Herschel photometry yield LFIR = (1.1 ± 0.1) × 1013 L⊙ and SFR ≈ 1300 M⊙ yr-1. Its molecular gas mass derived using the ultraluminous infrared galaxy conversion factor is 1.4 ± 0.2 × 1011M⊙ while the total interstellar medium mass derived from the 1.1 mm dust continuum is 3.7 ± 0.7 × 1011M⊙ assuming Td = 35 K. Our dynamical mass analysis suggests that the compact gas disc (r ≈ 1.1 kpc, inferred from dust continuum and spectral energy distribution analysis) has to be nearly face-on, providing a natural explanation for the uncommonly bright, compact stellar light seen by the HST. The [C II] line luminosity L_[C II]= 7.8± 1.1 × 10^9 L_{⊙} is remarkably high, but it is only 0.04 per cent of the total IR luminosity. AzTEC COSMOS-1 and other high redshift sources with a spatially resolved size extend the tight trend seen between [C II]/FIR ratio and ΣFIR among IR-bright galaxies reported by Díaz-Santos et al. by more than an order of magnitude, supporting the explanation that the higher intensity of the IR radiation field is responsible for the `[C II] deficiency' seen among luminous starburst galaxies.

  17. Solar activity indices as a proxy for the variation of ionospheric Total Electron Content (TEC) over Bahir Dar, Ethiopia during the year 2010-2014

    NASA Astrophysics Data System (ADS)

    Kassa, Tsegaye; Tilahun, Samson; Damtie, Baylie

    2017-09-01

    This paper was aimed at investigating the solar variations of vTEC as a function of solar activity parameters, EUV and F10.7 radio flux. The daily values of ionospheric vertical Total Electron Content (vTEC) were observed using a dual frequency GPS receiver deployed at Bahir Dar (11.6°N and 37.36°E), Ethiopia. Measurements were taken during the period of 2010-2014 for successive five years and analysis was done on only quiet day observations. A quadratic fit was used as a model to describe the daily variation of vTEC in relation to solar parameters. Linear and non-linear coefficients of the vTEC variations were calculated in order to capture the trend of the variation. The variation of vTEC have showed good agreement with the trend of solar parameters in almost all of the days we consider during the period of our observations. We have explicitly observed days with insignificant TECU deviation (eg. modeling with respect to EUV, DOY = 49 in 2010 and modeling with respect to F10.7, DOY = 125 in 2012 and the like) and days with maximum deviation (about 50 TECU). A maximum deviation were observed, on average, during months of equinox whereas minimum during solstice months. This implies that there is a need to consider more parameters, including EUV and F10.7, that can affect the variation of vTEC during equinox seasons. Relatively, small deviations was observed in modeling vTEC as a function of EUV compared to that of the variation due to F10.7 cm flux. This may also tell us that EUV can be more suitable in modeling the solar variation of vTEC especially for longterm trends. Even though, the linear trend of solar variations of vTEC was frequently observed, significant saturation and amplification trends of the solar variations of vTEC were also observed to some extent across the months of the years we have analyzed. This mixed trend of the solar variation of vTEC implies the need for thorough investigation on the effect of solar parameters on TEC. However, based on

  18. Adjustments of the TaD electron density reconstruction model with GNSS-TEC parameters for operational application purposes

    NASA Astrophysics Data System (ADS)

    Kutiev, Ivan; Marinov, Pencho; Fidanova, Stefka; Belehaki, Anna; Tsagouri, Ioanna

    2012-12-01

    Validation results on the latest version of TaD model (TaDv2) show realistic reconstruction of the electron density profiles (EDPs) with an average error of 3 TECU, similar to the error obtained from GNSS-TEC calculated paremeters. The work presented here has the aim to further improve the accuracy of the TaD topside reconstruction, adjusting the TEC parameter calculated from TaD model with the TEC parameter calculated by GNSS transmitting RINEX files provided by receivers co-located with the Digisondes. The performance of the new version is tested during a storm period demonstrating further improvements in respect to the previous version. Statistical comparison of modeled and observed TEC confirms the validity of the proposed adjustment. A significant benefit of the proposed upgrade is that it facilitates the real-time implementation of TaD. The model needs a reliable measure of the scale height at the peak height, which is supposed to be provided by Digisondes. Oftenly, the automatic scaling software fails to correctly calculate the scale height at the peak, Hm, due to interferences in the receiving signal. Consequently the model estimated topside scale height is wrongly calculated leading to unrealistic results for the modeled EDP. The proposed TEC adjustment forces the model to correctly reproduce the topside scale height, despite the inaccurate values of Hm. This adjustment is very important for the application of TaD in an operational environment.

  19. Short term variations of total electron content (TEC) fitting to a regional GPS network over the Kingdom of Saudi Arabia (KSA)

    NASA Astrophysics Data System (ADS)

    Alothman, A. O.; Alsubaie, M. A.; Ayhan, M. E.

    2011-09-01

    The ionosphere is a dispersive medium for radio waves with the refractive index which is a function of frequency and total electron content (TEC). TEC has a strong diurnal variation in addition to monthly, seasonal and solar cycle variations and small and large scale irregularities. Dual frequency GPS observations can be utilized to obtain TEC and investigate its spatial and temporal variations. We here studied short term TEC variations over the Kingdom of Saudi Arabia (KSA). A regional GPS network is formed consisting of 16 sites in and around KSA. GPS observations, acquired between 1st and 11th February 2009, were processed on a daily basis by using the Bernese v5.0 software and IGS final products. The geometry-free zero difference smoothed code observables were used to obtain two hour interval snapshots of TEC and their RMS errors at 0.5 × 0.5 degree grid nodes and regional ionosphere models in a spherical harmonics expansion to degree and order six. The equatorial ionized anomaly (EIA) is recovered in the south of 20°N from 08:00 to 12:00 UT. We found that day-by-day TEC variation is more stable than the night time variation.

  20. US-TEC: A new data assimilation product from the Space Environment Center characterizing the ionospheric total electron content using real-time GPS data

    NASA Astrophysics Data System (ADS)

    Fuller-Rowell, Tim; Araujo-Pradere, Eduardo; Minter, Cliff; Codrescu, Mihail; Spencer, Paul; Robertson, Doug; Jacobson, Abram R.

    2006-12-01

    The potential of data assimilation for operational numerical weather forecasting has been appreciated for many years. For space weather it is a new path that we are just beginning to explore. With the emergence of satellite constellations and the networks of ground-based observations, sufficient data sources are now available to make the application of data assimilation techniques a viable option. The first space weather product at Space Environment Center (SEC) utilizing data assimilation techniques, US-TEC, was launched as a test operational product in November 2004. US-TEC characterizes the ionospheric total electron content (TEC) over the continental United States (CONUS) every 15 min with about a 15-min latency. US-TEC is based on a Kalman filter data assimilation scheme driven by a ground-based network of real-time GPS stations. The product includes a map of the vertical TEC, an estimate of the uncertainty in the map, and the departure of the TEC from a 10-day average at that particular universal time. In addition, data files are provided for vertical TEC and the line-of-sight electron content to all GPS satellites in view over the CONUS at that time. The information can be used to improve single-frequency GPS positioning by providing more accurate corrections for the ionospheric signal delay, or it can be used to initialize rapid integer ambiguity resolution schemes for dual-frequency GPS systems. Validation of US-TEC indicates an accuracy of the line-of-sight electron content of between 2 and 3 TEC units (1 TECU = 1016 el m-2), equivalent to less than 50 cm signal delay at L1 frequencies, which promises value for GPS users. This is the first step along a path that will likely lead to major improvement in space weather forecasting, paralleling the advances achieved in meteorological weather forecasting.

  1. Modeling of Heat and Mass Transfer in a TEC-Driven Lyophilizer

    NASA Technical Reports Server (NTRS)

    Yuan, Zeng-Guang; Hegde, Uday; Litwiller, Eric; Flynn, Michael; Fisher, John

    2006-01-01

    Dewatering of wet waste during space exploration missions is important for crew safety as it stabilizes the waste. It may also be used to recover water and serve as a preconditioning step for waste compaction. A thermoelectric cooler (TEC)-driven lyophilizer is under development at NASA Ames Research Center for this purpose. It has three major components: (i) an evaporator section where water vapor sublimes from the frozen waste, (ii) a condenser section where this water vapor deposits as ice, and (iii) a TEC section which serves as a heat pump to transfer heat from the condenser to the evaporator. This paper analyses the heat and mass transfer processes in the lyophilizer in an effort to understand the ice formation behavior in the condenser. The analysis is supported by experimental observations of ice formation patterns in two different condenser units.

  2. X-Ray Crystal Structure of Bone Marrow Kinase in the X Chromosome: A Tec Family Kinase

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

    Muckelbauer, Jodi; Sack, John S.; Ahmed, Nazia

    Bone marrow kinase in the X chromosome, a member of the Tec family of tyrosine kinases, plays a role in both monocyte/macrophage trafficking as well as cytokine secretion. Although the structures of Tec family kinases Bruton's tyrosine kinase and IL-2-inducible T-cell kinase are known, the crystal structures of other Tec family kinases have remained elusive. We report the X-ray crystal structures of bone marrow kinase in the X chromosome in complex with dasatinib at 2.4 {angstrom} resolution and PP2 at 1.9 {angstrom} resolution. The bone marrow kinase in the X chromosome structures reveal a typical kinase protein fold; with well-orderedmore » protein conformation that includes an open/extended activation loop and a stabilized DFG-motif rendering the kinase in an inactive conformation. Dasatinib and PP2 bind to bone marrow kinase in the X chromosome in the ATP binding pocket and display similar binding modes to that observed in other Tec and Src protein kinases. The bone marrow kinase in the X chromosome structures identify conformational elements of the DFG-motif that could potentially be utilized to design potent and/or selective bone marrow kinase in the X chromosome inhibitors.« less

  3. (Sub)millimetre interferometric imaging of a sample of COSMOS/AzTEC submillimetre galaxies. I. Multiwavelength identifications and redshift distribution

    NASA Astrophysics Data System (ADS)

    Miettinen, O.; Smolčić, V.; Novak, M.; Aravena, M.; Karim, A.; Masters, D.; Riechers, D. A.; Bussmann, R. S.; McCracken, H. J.; Ilbert, O.; Bertoldi, F.; Capak, P.; Feruglio, C.; Halliday, C.; Kartaltepe, J. S.; Navarrete, F.; Salvato, M.; Sanders, D.; Schinnerer, E.; Sheth, K.

    2015-05-01

    We used the Plateau de Bure Interferometer (PdBI) to map a sample of 15 submillimetre galaxies (SMGs) in the COSMOS field at the wavelength of 1.3 mm. The target SMGs were originally discovered in the James Clerk Maxwell Telescope (JCMT)/AzTEC 1.1 mm continuum survey at S/N1.1 mm = 4-4.5. This paper presents, for the first time, interferometric millimetre-wavelength observations of these sources. The angular resolution of our observations, 1''&dotbelow;8, allowed us to accurately determine the positions of the target SMGs. Using a detection threshold of S/N1.3 mm> 4.5 regardless of multiwavelength counterpart association, and 4 TEC19. Three of our detected SMGs (AzTEC21, 27, and 28; which corresponds to 20%) are marginally resolved at our angular resolution, and these sources are found to have elongated or clumpy morphologies and/or multiple components. Using optical to near-infrared photometric redshifts, available spectroscopic redshifts, and redshifts estimated from the radio-to-submm spectral index we infer a median redshift of tilde{z}= 3.20 ± 0.25 for our sample. To study the overall multiplicity and redshift distribution of flux-limited samples of SMGs we combined these sources with the 15 brightest JCMT/AzTEC SMGs detected at 1.1 mm, AzTEC1-15, and studied previously. This constitutes a complete, flux- and S/N-limited 1.1-mm selected sample. We find that the median redshift for the 15 brightest JCMT/AzTEC SMGs (tilde{z}= 3.05 ± 0.44) is consistent with that for AzTEC16-30. This conforms to recent observational findings that SMGs do not exhibit any significant trend between the redshift and (sub)mm flux density. For the combined AzTEC1-30 sample we derive a median redshift of tilde{z}= 3.17 ± 0.27, consistent with previous results based on mm

  4. GPS TEC near the crest of the EIA at 95°E during the ascending half of solar cycle 24 and comparison with IRI simulations

    NASA Astrophysics Data System (ADS)

    Bhuyan, Pradip Kumar; Hazarika, Rumajyoti

    2013-10-01

    Total electron content (TEC) data obtained from GPS dual frequency measurements during the ascending half of the solar cycle 24 from 2009 to 2012 over Dibrugarh (27.5°N, 94.9°E; 17.6°N MLAT) have been used to study the diurnal, seasonal, annual and solar cycle variation of TEC. The measurements reported here are for the first time from the location situated at the poleward edge of the northern equatorial ionization anomaly (EIA) and within the peak region of the longitudinal wave number 4 (WN4) structure in EIA crest TEC. TEC exhibits a minimum around 0600 LT and diurnal maximum around 1300-1600 LT. In the low and moderate solar activity years 2009-2010 and 2010-2011, average daytime (1000-1600 LT) TEC in summer was higher (25.4 and 36.6 TECU) compared to that in winter (21.5 and 26.1 TECU). However, at the peak of the solar cycle in 2011-2012, reversal in the level of ionization between winter and summer takes place and winter TEC becomes higher (50.6 TECU) than that in summer (45.0 TECU). Further, TEC in spring (34.1, 49.9 and 63.3 TECU respectively in 2009-10, 2010-11 and 2011-12) is higher than that in autumn (24.2, 32.3 and 51.9 TECU respectively) thus showing equinoctial asymmetry in all the years of observation. The winter anomaly in high solar activity years and equinoctial asymmetry all throughout may be largely attributed to changes in the thermospheric O/N2 density ratio. A winter to summer delay of ˜1 h in the time of occurrence of the diurnal maximum has also been observed. Daytime maximum TEC bears a nonlinear relationship with F10.7 cm solar flux. TEC increases linearly with F10.7 cm solar flux initially up to about 140 sfu (1 sfu = 10-22 W m-2 Hz-1) after which it tends to saturate. On the contrary, TEC increases linearly with solar EUV flux (photons cm-2 s-1, 0.5-50 nm) during the same period. TEC predicted by the IRI 2012 are lower than the measured TEC for nearly 90% of the time.

  5. Statistical characteristics of seismo-ionospheric GPS TEC disturbances prior to global Mw ≥ 5.0 earthquakes (1998-2014)

    NASA Astrophysics Data System (ADS)

    Shah, Munawar; Jin, Shuanggen

    2015-12-01

    Pre-earthquake ionospheric anomalies are still challenging and unclear to obtain and understand, particularly for different earthquake magnitudes and focal depths as well as types of fault. In this paper, the seismo-ionospheric disturbances (SID) related to global earthquakes with 1492 Mw ≥ 5.0 from 1998 to 2014 are investigated using the total electron content (TEC) of GPS global ionosphere maps (GIM). Statistical analysis of 10-day TEC data before global Mw ≥ 5.0 earthquakes shows significant enhancement 5 days before an earthquake of Mw ≥ 6.0 at a 95% confidence level. Earthquakes with a focal depth of less than 60 km and Mw ≥ 6.0 are presumably the root of deviation in the ionospheric TEC because earthquake breeding zones have gigantic quantities of energy at shallower focal depths. Increased anomalous TEC is recorded in cumulative percentages beyond Mw = 5.5. Sharpness in cumulative percentages is evident in seismo-ionospheric disturbance prior to Mw ≥ 6.0 earthquakes. Seismo-ionospheric disturbances related to strike slip and thrust earthquakes are noticeable for magnitude Mw6.0-7.0 earthquakes. The relative values reveal high ratios (up to 2) and low ratios (up to -0.5) within 5 days prior to global earthquakes for positive and negative anomalies. The anomalous patterns in TEC related to earthquakes are possibly due to the coupling of high amounts of energy from earthquake breeding zones of higher magnitude and shallower focal depth.

  6. Effect of geomagnetic storms of different solar origin on the ionospheric TEC

    NASA Astrophysics Data System (ADS)

    Mansoori, Azad A.; Khan, Parvaiz A.; Purohit, P. K.

    2018-05-01

    We have studied the behaviour of ionospheric Total Electron Content (TEC) at a mid latitude station Usuda (36.130N, 138.360E), Japan during intense geomagnetic storms which were observed during 23 solar cycle (1998-2006). For the present study we have selected 47 intense geomagnetic storms (Dst≤-100nT), for the given period, which were then categorised into four categories depending upon their solar and interplanetary sources like Magnetic Cloud (MC), Co-rotating Interaction Region (CIR), Sheath driven Interplanetary Coronal Mass Ejection (SH+ICME) and Sheath driven Magnetic cloud (SH+MC). From our study we found that the geomagnetic storms significantly affect the ionosphere having any of the solar origin. However the geomagnetic storms which are either caused by SH+MC or SH+ICME produced maximum effect in TEC.

  7. Global features of ionospheric slab thickness derived from JPL TEC and COSMIC observations

    NASA Astrophysics Data System (ADS)

    Huang, He; Liu, Libo

    2016-04-01

    The ionospheric equivalent slab thickness (EST) is the ratio of total electron content (TEC) to F2-layer peak electron density (NmF2), describing the thickness of the ionospheric profile. In this study, we retrieve EST from Jet Propulsion Laboratory (JPL) TEC data and NmF2 retrieved from Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) ionospheric radio occultation data. The diurnal, seasonal and solar activity variations of global EST are analyzed as the excellent spatial coverage of JPL TEC and COSMIC data. During solstices, daytime EST in the summer hemisphere is larger than that in the winter hemisphere, except in some high-latitude regions; and the reverse is true for the nighttime EST. The peaks of EST often appear at 0400 local time. The pre-sunrise enhancement in EST appears in all seasons, while the post-sunset enhancement in EST is not readily observed in equinox. The dependence of EST on solar activity is very complicated. Furthermore, an interesting phenomenon is found that EST is enhanced from 0° to 120° E in longitude and 30° to 75° S in latitude during nighttime, just to the east of Weddell Sea Anomaly, during equinox and southern hemisphere summer.

  8. V-TECS Criterion-Referenced Test Item Bank for Radiologic Technology Occupations.

    ERIC Educational Resources Information Center

    Reneau, Fred; And Others

    This Vocational-Technical Education Consortium of States (V-TECS) criterion-referenced test item bank provides 696 multiple-choice items and 33 matching items for radiologic technology occupations. These job titles are included: radiologic technologist, chief; radiologic technologist; nuclear medicine technologist; radiation therapy technologist;…

  9. Comparison of plateletpheresis on the Fresenius AS.TEC 204 and Haemonetics MCS 3p.

    PubMed

    Ranganathan, Sudha

    2007-02-01

    This is an attempt at comparing two cell separators for plateletpheresis, namely the Fresenius AS.TEC 204 and Haemonetics MCS 3p, at a tertiary care center in India. Donors who weighed between 55-75 kg, who had a hematocrit of 41-43%, and platelet counts of 250x10(3)-400x10(3)/microl were selected for the study. The comparability of the donors who donated on the two cell separators were analysed by t-test independent samples and no significant differences were found (P>0.05). The features compared were time taken for the procedure, volume processed on the separators, adverse reactions of the donors, quality control of the product, separation efficiency of the separators, platelet loss in the donors after the procedure, and the predictor versus the actual yield of platelets given by the cell separator. The volume processed to get a target yield of >3x10(11) was equal to 2.8-3.2 l and equal in both the cell separators. Symptoms of citrate toxicity were seen in 4 and 2.5% of donors who donated on the MCS 3p and the AS.TEC 204, respectively, and 3 and 1% of donors, respectively, had vasovagal reactions. All the platelet products collected had a platelet count of >3x10(11); 90% of the platelet products collected on the AS.TEC 204 attained the predicted yield that was set on the cell separator where as 75% of the platelet products collected on the MCS 3p attained the target yield. Quality control of the platelets collected on both the cell separators complied with the standards except that 3% of the platelets collected on the MCS 3p had a visible red cell contamination. The separation efficiency of the MCS 3p was higher, 50-52% as compared to the 40-45% on the AS.TEC 204. A provision of double venous access, less adverse reactions, negligible RBC contamination with a better predictor yield of platelets makes the AS.TEC 204 a safer and more reliable alternative than the widely used Haemonetics MCS 3p. Copyright (c) 2006 Wiley-Liss, Inc.

  10. SH2 dependent autophosphorylation within the Tec family kinase Itk

    PubMed Central

    Joseph, Raji E.; Severin, Andrew; Min, Lie; Fulton, D. Bruce; Andreotti, Amy H.

    2009-01-01

    The Tec family kinase, Itk, undergoes an in cis autophosphorylation on Y180 within its SH3 domain. Autophosphorylation of the Itk SH3 domain by the Itk kinase domain is strictly dependent on the presence of the intervening SH2 domain. A direct docking interaction between the Itk kinase and SH2 domains brings the Itk SH3 domain into the active site where Y180 is then phosphorylated. We now identify the residues on the surface of the Itk SH2 domain responsible for substrate docking and show that this SH2 surface mediates autophosphorylation in the full length Itk molecule. The canonical phospholigand binding site on the SH2 domain is not involved in substrate docking, instead the docking site consists of side chains from three loop regions (AB, EF and BG) and part of the βD strand. These results are extended into Btk, a Tec family kinase linked to the B cell deficiency X-linked agammaglobulinemia (XLA). Our results suggest that some XLA causing mutations might impair Btk phosphorylation. PMID:19523959

  11. Estimation of total electron content (TEC) using spaceborne GPS measurements

    NASA Astrophysics Data System (ADS)

    Choi, Key-Rok; Lightsey, E. Glenn

    2008-09-01

    TerraSAR-X (TSX), a high-resolution interferometric Synthetic Aperture Radar (SAR) mission from DLR (German Aerospace Center, Deutsches Zentrum für Luft-und Raumfahrt), was successfully launched into orbit on June 15, 2007. It includes a dual-frequency GPS receiver called IGOR (Integrated GPS Occultation Receiver), which is a heritage NASA/JPL BlackJack receiver. The software for the TSX IGOR receiver was specially-modified software developed at UT/CSR. This software was upgraded to provide enhanced occultation capabilities. This paper describes total electron content (TEC) estimation using simulation data and onboard GPS data of TerraSAR-X. The simulated GPS data were collected using the IGOR Engineering Model (EM) in the laboratory and the onboard GPS data were collected from the IGOR Flight Model (FM) on TSX. To estimate vertical total electron content (vTEC) for the simulation data, inter-frequency biases (IFB) were estimated using the "carrier to code leveling process." For the onboard GPS data, IFBs of GPS satellites were retrieved from the navigation message and applied to the measurements.

  12. Invesion of tsunami height using GPS TEC data. The case of the 2012 Haida Gwaii tsunami and Earthquake.

    NASA Astrophysics Data System (ADS)

    Rakoto, V.; Lognonne, P. H.; Rolland, L. M.

    2015-12-01

    Large earthquakes (i.eM>6) and tsunamis associated are responsible for ionospheric perturbations. These perturbations can be observed in the total electron content (TEC) measured from multi- frequency Global Navigation Satellite systems (GNSS) data (e.g GPS). We will focus on the studies of the Haïda Gwaii earthquake and tsunami case. It happened the 28 october 2012 along the Queen Charlotte fault of the Canada Western Coast. First, we compare GPS data of perturbation TEC to our model. We model the TEC perturbation in several steps. (1) First, we compute tsunami normal modes modes in atmosphere in using PREM model with 4.7km of oceanic layer. (2) We sum all the tsunami modes to obtain the neutral displacement. (3) We couple the ionosphere with the neutral atmosphere. (4) We integrate the perturbed electron density along each satellite station line of sight. At last, we present first results of TEC inversion in order to retrieve the waveform of the tsunami. This inversion has been done on synthetics data assuming Queen Charlotte Earthquake and Tsunami can be considered as a point source in far field.

  13. Wide extragalactic (sub-)millimeter surveys with SCUBA and AzTEC

    NASA Astrophysics Data System (ADS)

    Aretxaga, I.; Hughes, D. H.; SHADES Collaboration; AzTEC Collaboration

    2009-05-01

    We summarize the present status of our knowledge of the millimeter galaxy population derived from extensive (sub-) millimeter extragalactic surveys like the SCUBA HAlf Degree Survey (SHADES), and the current status of the next generation of surveys traced with the AzTEC camera, that has, so far, surveyed more than 2 degrees at 1.1wavelengths.

  14. Characteristics of equatorial plasma bubbles observed by TEC map based on ground-based GNSS receivers over South America

    NASA Astrophysics Data System (ADS)

    Barros, Diego; Takahashi, Hisao; Wrasse, Cristiano M.; Figueiredo, Cosme Alexandre O. B.

    2018-01-01

    A ground-based network of GNSS receivers has been used to monitor equatorial plasma bubbles (EPBs) by mapping the total electron content (TEC map). The large coverage of the TEC map allowed us to monitor several EPBs simultaneously and get characteristics of the dynamics, extension and longitudinal distributions of the EPBs from the onset time until their disappearance. These characteristics were obtained by using TEC map analysis and the keogram technique. TEC map databases analyzed were for the period between November 2012 and January 2016. The zonal drift velocities of the EPBs showed a clear latitudinal gradient varying from 123 m s-1 at the Equator to 65 m s-1 for 35° S latitude. Consequently, observed EPBs are inclined against the geomagnetic field lines. Both zonal drift velocity and the inclination of the EPBs were compared to the thermospheric neutral wind, which showed good agreement. Moreover, the large two-dimensional coverage of TEC maps allowed us to study periodic EPBs with a wide longitudinal distance. The averaged values observed for the inter-bubble distances also presented a clear latitudinal gradient varying from 920 km at the Equator to 640 km at 30° S. The latitudinal gradient in the inter-bubble distances seems to be related to the difference in the zonal drift velocity of the EPB from the Equator to middle latitudes and to the difference in the westward movement of the terminator. On several occasions, the distances reached more than 2000 km. Inter-bubble distances greater than 1000 km have not been reported in the literature.

  15. Seasonal and solar cycle effects on TEC at 95°E in the ascending half (2009-2014) of the subdued solar cycle 24: Consistent underestimation by IRI 2012

    NASA Astrophysics Data System (ADS)

    Kakoti, Geetashree; Bhuyan, Pradip Kumar; Hazarika, Rumajyoti

    2017-07-01

    TEC measured at Dibrugarh (27.5°N, 94.9°E, 17.5°N Geomag.) from 2009 to 2014 is used to study its temporal characteristics during the ascending half of solar cycle 24. The measurements provide an opportunity to assess the diurnal, seasonal and longterm predictability of the IRI 2012 (with IRI Nequick, IRI01-corr, IRI 2001topside options) during this solar cycle which is distinctively low in magnitude compared to the previous cycles. The low latitude station Dibrugarh is normally located at the poleward edge of the northern EIA. A semi-annual variation in GPS TEC is observed with the peaks occurring in the equinoxes. The peak in spring (March, April) is higher than that in autumn (September, October) irrespective of the year of observation. The spring autumn asymmetry is also observed in IRI TEC. In contrast, the winter (November, December, January, February) anomaly is evident only in high activity years. TEC bears a distinct nonlinear relationship with 10.7 cm solar flux (F10.7). TEC increases linearly with F10.7 up to about 125 sfu beyond which it tends to saturate. The correlation between TEC and solar flux is found to be a function of local time and peaks at 10:00 LT. TEC varies nonlinearly with solar EUV flux similar to its variation with F10.7. The nonlinearity is well captured by the IRI. The saturation of TEC at high solar activity is attributed to the inability of the ionosphere to accommodate more ionization after it reaches the level of saturation ion pressure. Annual mean TEC increased from the minimum in 2009 almost linearly till 2012, remains at the same level in 2013 and then increased again in 2014. IRI TEC shows a linear increase from 2009 to 2014. IRI01-corr and IRI-NeQuick TEC are nearly equal at all local times, season and year of observation while IRI-2001 simulated TEC are always higher than that simulated by the other two versions. The IRI 2012 underestimates the TEC at about all local times except for a few hours in the midday in all

  16. Study of TEC and foF2 with the Help of GPS and Ionosonde Data over Maitri, Antarctica

    NASA Astrophysics Data System (ADS)

    Khatarkar, Prakash; Gwal, Ashok Kumar

    Prakash Khatarkar, Purusottam Bhaware, Azad Ahmad Mansoori, Varsha Kachneria, Shweta Thakur, and A. K. Gwal Abstract The behavior of ionosphere can be diagnosed by a number of techniques. The common techniques used are the space based Global Positioning System and the ground based Ionosonde. We have compared the variability of ionospheric parameters by using two different techniques GPS and Ionosonde, during December 2009 to November 2010 at the Indian base station Maitri (11.45E, 70.45S). The comparison between the measurements of two techniques was realized through the Total Electron Content (TEC) parameters derived by using different methods. The comparison was made diurnally, seasonally, polar day and polar night variations and the annually. From our analysis we found that a strong correlation exists between the GPS derived TEC and Ionosonde derived foF2 during the day period while during the night time the correlation is insignificant. At the same time we found that a strong correlation exists between the Ionosonde and GPS derived TEC. The pattern of variation of ionospheric parameters derived from two techniques is strikingly similar indicating that the high degree of synchronization between them. This has a practical applicability by allowing calculating the error in one technique by comparing with other. Keywords: Ionosphere, Ionosonde, GPS, foF2, TEC.

  17. Structures of human Bruton's tyrosine kinase in active and inactive conformations suggest a mechanism of activation for TEC family kinases

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

    Marcotte, Douglas J.; Liu, Yu-Ting; Arduini, Robert M.

    Bruton's tyrosine kinase (BTK), a member of the TEC family of kinases, plays a crucial role in B-cell maturation and mast cell activation. Although the structures of the unphosphorylated mouse BTK kinase domain and the unphosphorylated and phosphorylated kinase domains of human ITK are known, understanding the kinase selectivity profiles of BTK inhibitors has been hampered by the lack of availability of a high resolution, ligand-bound BTK structure. Here, we report the crystal structures of the human BTK kinase domain bound to either Dasatinib (BMS-354825) at 1.9 {angstrom} resolution or to 4-amino-5-(4-phenoxyphenyl)-7H-pyrrolospyrimidin- 7-yl-cyclopentane at 1.6 {angstrom} resolution. This data providesmore » information relevant to the development of small molecule inhibitors targeting BTK and the TEC family of nonreceptor tyrosine kinases. Analysis of the structural differences between the TEC and Src families of kinases near the Trp-Glu-Ile motif in the N-terminal region of the kinase domain suggests a mechanism of regulation of the TEC family members.« less

  18. Radio Identification of Millimeter-Bright Galaxies Detected in the AzTEC/ASTE Blank Field Survey

    NASA Astrophysics Data System (ADS)

    Hatsukade, Bunyo; Kohno, Kotaro; White, Glenn; Matsuura, Shuji; Hanami, Hitoshi; Shirahata, Mai; Nakanishi, Kouichiro; Hughes, David; Tamura, Yoichi; Iono, Daisuke; Wilson, Grant; Yun, Min

    2008-10-01

    We propose a deep 1.4-GHz imaging of millimeter-bright sources in the AzTEC/ASTE 1.1-mm blank field survey of AKARI Deep Field-South. The AzTEC/ASTE uncovered 37 sources, which are possibly at z > 2. We have obtained multi-wavelength data in this field, but the large beam size of AzTEC/ASTE (30 arcsec) prevents us from identifying counterparts. The aim of this proposal is to identify radio counterparts with higher-angular resolution. This enables us (i) To identifying optical/IR counterparts. It enables optical spectroscopy to determine precise redshifts, allowing us to derive SFRs, luminosity functions, clustering properties, mass of dark matter halos, etc. (ii) To constrain luminosity evolutions of SMGs by comparing of 1.4-GHz number counts (and luminosity functions) with luminosity evolution models. (iii) To estimate photometric redshifts from 1.4-GHz and 1.1-mm data using the radio-FIR flux correlation. In case of non-detection, we can put deep lower limits (3 sigma limit of z > 3). These information lead to the study of evolutionary history of SMGs, their relationship with other galaxy populations, contribution to the cosmic star formation history and the infrared background.

  19. Comparison of GPS-TEC variation during quiet and disturbed period using the Holt-Winter method and IRI-2012 model over Malaysia

    NASA Astrophysics Data System (ADS)

    Ahmed Ismail, Nouf Abd Emunim; Abdullah, Mardina; Hasbi, Alina Marie

    2016-07-01

    Total Electron Content (TEC) is the main parameter in the ionosphere that has significant effects on radio wave; it changes the speed and direction of the signal propagation, causing the delay of the Global Positioning System (GPS) signals. Therefore, it is crucial to validate the performance of the ionospheric model to reveal the variety of ionospheric behaviour during quiet and disturbed period. This research presents the performance evaluation of the statistical Holt-Winter method and IRI-2012 model using three topside electron density options: IRI-2001, IRI01-corr and NeQuick with the observed GPS-TEC during quiet and disturbed period. The GPS-TEC data were derived from the dual frequency GPS receiver at JUPEM (Department of Survey and Mapping Malaysia), from the UUMK station (north Peninsular Malaysia) at geographic coordinates of 6.46°N-100.50°E and geomagnetic coordinates of 3.32°S-172.99°E and TGPG station (south Peninsular Malaysia) at geographic coordinates of 1.36°N-104.10°E and geomagnetic coordinates of 8.43°S -176.53°E, during March of 2013. The maximum value of the GPS-TEC was at the post noon time at 17:00 LT and the minimum was in the early morning from 6:00-7:00 LT. During the quiet period, the maximum GPS-TEC at the UUMK station was 52 TECU while at the TGPG station, it was 60 TECU. During the disturbed period, when intense geomagnetic storm occurred on 17 March 2013, the maximum GPS-TEC recorded was 58 TECU and 65 TECU in UUMK and TGPG station, respectively. The diurnal hourly variation during the quiet period indicated that IRI-2001, IRI01-corr, and NeQuick had overestimation agreement during the day hours except for the time between 11:00-19:00 LT when IRI01-corr and NeQuick showed underestimation, while during 13:00-20:00 LT, IRI-2001 showed slight underestimation whereas the Holt-Winter method showed good agreement with GPS-TEC. During the disturbed period, IRI-2001 showed overestimation agreement for all hours, while the IRI01-corr

  20. SH2-dependent autophosphorylation within the Tec family kinase Itk.

    PubMed

    Joseph, Raji E; Severin, Andrew; Min, Lie; Fulton, D Bruce; Andreotti, Amy H

    2009-08-07

    The Tec family kinase, Itk (interleukin-2 tyrosine kinase), undergoes an in cis autophosphorylation on Y180 within its Src homology 3 (SH3) domain. Autophosphorylation of the Itk SH3 domain by the Itk kinase domain is strictly dependent on the presence of the intervening Src homology 2 (SH2) domain. A direct docking interaction between the Itk kinase and SH2 domains brings the Itk SH3 domain into the active site where Y180 is then phosphorylated. We now identify the residues on the surface of the Itk SH2 domain responsible for substrate docking and show that this SH2 surface mediates autophosphorylation in the full-length Itk molecule. The canonical phospholigand binding site on the SH2 domain is not involved in substrate docking, instead the docking site consists of side chains from three loop regions (AB, EF and BG) and part of the betaD strand. These results are extended into Btk (Bruton's tyrosine kinase), a Tec family kinase linked to the B-cell deficiency X-linked agammaglobulinemia (XLA). Our results suggest that some XLA-causing mutations might impair Btk phosphorylation.

  1. THE REDSHIFT AND NATURE OF AzTEC/COSMOS 1: A STARBURST GALAXY AT z = 4.6

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

    Smolcic, V.; Capak, P.; Blain, A. W.

    2011-04-20

    Based on broadband/narrowband photometry and Keck DEIMOS spectroscopy, we report a redshift of z = 4.64{sup +0.06}{sub -0.08} for AzTEC/COSMOS 1, the brightest submillimeter galaxy (SMG) in the AzTEC/COSMOS field. In addition to the COSMOS-survey X-ray to radio data, we report observations of the source with Herschel/PACS (100, 160 {mu}m), CSO/SHARC II (350 {mu}m), and CARMA and PdBI (3 mm). We do not detect CO(5 {yields} 4) line emission in the covered redshift ranges, 4.56-4.76 (PdBI/CARMA) and 4.94-5.02 (CARMA). If the line is within this bandwidth, this sets 3{sigma} upper limits on the gas mass to {approx}<8 x 10{sup 9}more » M{sub sun} and {approx}<5 x 10{sup 10} M{sub sun}, respectively (assuming similar conditions as observed in z {approx} 2 SMGs). This could be explained by a low CO-excitation in the source. Our analysis of the UV-IR spectral energy distribution of AzTEC 1 shows that it is an extremely young ({approx}<50 Myr), massive (M{sub *} {approx} 10{sup 11} M{sub sun}), but compact ({approx}<2 kpc) galaxy, forming stars at a rate of {approx}1300 M{sub sun} yr{sup -1}. Our results imply that AzTEC 1 is forming stars in a 'gravitationally bound' regime in which gravity prohibits the formation of a superwind, leading to matter accumulation within the galaxy and further generations of star formation.« less

  2. Application of IRI-Plas in Ionospheric Tomography and HF Communication Studies with Assimilation of GPS-TEC

    NASA Astrophysics Data System (ADS)

    Arikan, Feza; Gulyaeva, Tamara; Sezen, Umut; Arikan, Orhan; Toker, Cenk; Hakan Tuna, MR.; Erdem, Esra

    2016-07-01

    International Reference Ionosphere is the most acknowledged climatic model of ionosphere that provides electron density profile and hourly, monthly median values of critical layer parameters of the ionosphere for a desired location, date and time between 60 to 2,000 km altitude. IRI is also accepted as the International Standard Ionosphere model. Recently, the IRI model is extended to the Global Positioning System (GPS) satellite orbital range of 20,000 km. The new version is called IRI-Plas and it can be obtained from http://ftp.izmiran.ru/pub/izmiran /SPIM/. A user-friendly online version is also provided at www.ionolab.org as a space weather service. Total Electron Content (TEC), which is defined as the line integral of electron density on a given ray path, is an observable parameter that can be estimated from earth based GPS receivers in a cost-effective manner as GPS-TEC. One of the most important advantages of IRI-Plas is the possible input of GPS-TEC to update the background deterministic ionospheric model to the current ionospheric state. This option is highly useful in regional and global tomography studies and HF link assessments. IONOLAB group currently implements IRI-Plas as a background model and updates the ionospheric state using GPS-TEC in IONOLAB-CIT and IONOLAB-RAY algorithms. The improved state of ionosphere allows the most reliable 4-D imaging of electron density profiles and HF and satellite communication link simulations.This study is supported by TUBITAK 115E915 and joint TUBITAK 114E092 and AS CR 14/001.

  3. Real time validation of GPS TEC precursor mask for Greece

    NASA Astrophysics Data System (ADS)

    Pulinets, Sergey; Davidenko, Dmitry

    2013-04-01

    It was established by earlier studies of pre-earthquake ionospheric variations that for every specific site these variations manifest definite stability in their temporal behavior within the time interval few days before the seismic shock. This self-similarity (characteristic to phenomena registered for processes observed close to critical point of the system) permits us to consider these variations as a good candidate to short-term precursor. Physical mechanism of GPS TEC variations before earthquakes is developed within the framework of Lithosphere-Atmosphere-Ionosphere Coupling (LAIC) model. Taking into account the different tectonic structure and different source mechanisms of earthquakes in different regions of the globe, every site has its individual behavior in pre-earthquake activity what creates individual "imprint" on the ionosphere behavior at every given point. Just this so called "mask" of the ionosphere variability before earthquake in the given point creates opportunity to detect anomalous behavior of electron concentration in ionosphere basing not only on statistical processing procedure but applying the pattern recognition technique what facilitates the automatic recognition of short-term ionospheric precursors of earthquakes. Such kind of precursor mask was created using the GPS TEC variation around the time of 9 earthquakes with magnitude from M6.0 till M6.9 which took place in Greece within the time interval 2006-2011. The major anomaly revealed in the relative deviation of the vertical TEC was the positive anomaly appearing at ~04PM UT one day before the seismic shock and lasting nearly 12 hours till ~04AM UT. To validate this approach it was decided to check the mask in real-time monitoring of earthquakes in Greece starting from the 1 of December 2012 for the earthquakes with magnitude more than 4.5. During this period (till 9 of January 2013) 4 cases of seismic shocks were registered, including the largest one M5.7 on 8 of January. For all of

  4. Performance evaluation of GIM-TEC assimilation of the IRI-Plas model at two equatorial stations in the American sector

    NASA Astrophysics Data System (ADS)

    Adebiyi, S. J.; Adebesin, B. O.; Ikubanni, S. O.; Joshua, B. W.

    2017-05-01

    Empirical models of the ionosphere, such as the International Reference Ionosphere (IRI) model, play a vital role in evaluating the environmental effect on the operation of space-based communication and navigation technologies. The IRI extended to Plasmasphere (IRI-Plas) model can be adjusted with external data to update its electron density profile while still maintaining the overall integrity of the model representations. In this paper, the performance of the total electron content (TEC) assimilation option of the IRI-Plas at two equatorial stations, Jicamarca, Peru (geographic: 12°S, 77°W, dip angle 0.8°) and Cachoeira Paulista, Brazil (Geographic: 22.7°S, 45°W, dip angle -26°), is examined during quiet and disturbed conditions. TEC, F2 layer critical frequency (foF2), and peak height (hmF2) predicted when the model is operated without external input were used as a baseline in our model evaluation. Results indicate that TEC predicted by the assimilation option generally produced smaller estimation errors compared to the "no extra input" option during quiet and disturbed conditions. Generally, the error is smaller at the equatorial trough than near the crest for both quiet and disturbed days. With assimilation option, there is a substantial improvement of storm time estimations when compared with quiet time predictions. The improvement is, however, independent on storm's severity. Furthermore, the modeled foF2 and hmF2 are generally poor with TEC assimilation, particularly the hmF2 prediction, at the two locations during both quiet and disturbed conditions. Consequently, IRI-Plas model assimilated with TEC value only may not be sufficient where more realistic instantaneous values of peak parameters are required.

  5. TEC variations over North-western Balkan Peninsula before and during the seismic activity of 24th May 2009

    NASA Astrophysics Data System (ADS)

    Contadakis, M. E.; Arabelos, D. N.; Vergos, G.

    2012-04-01

    In this paper the Total Electron Content (TEC) data of 8 Global Positioning System (GPS) stations of the EUREF network, 4 close and 4 remote to EQ epicentre stations, which are being provided by IONOLAB (Turkey), were analysed using wavelet analysis and Discrete Fourier Analysis in order to investigate the TEC variations over North-western Balkan Peninsula before and during the seismic activity of 24th of May, 2009. The main conclusions of this analysis are the following. (a) TEC oscillations in a broad range of frequencies occur randomly over a broad area of several hundred km from the earthquake and (b) high frequency oscillations (f ≥ 0.0003Hz, periods T ≤ 60m) seems to point to the location of the earthquake with a questionable accuracy but the fractal characteristics of the frequencies distribution, points to the locus of the earthquake with a rather higher accuracy. We conclude that the LAIC mechanism through acoustic or gravity wave could explain this phenomenology.

  6. Measuring Ionospheric Irregularities Globally by the Rate of TEC Index and GNSS Networks

    NASA Technical Reports Server (NTRS)

    Pi, Xiaoqing

    2012-01-01

    Outline of presentation: Why do we use the rate of TEC index (ROTI) instead of the standard s4 and sigma-phi indices? What are the differences between S4, sigma-phi and ROTI? Examples of ROTI measurements and Development status and plan.

  7. Comparison of outliers and novelty detection to identify ionospheric TEC irregularities during geomagnetic storm and substorm

    NASA Astrophysics Data System (ADS)

    Pattisahusiwa, Asis; Houw Liong, The; Purqon, Acep

    2016-08-01

    In this study, we compare two learning mechanisms: outliers and novelty detection in order to detect ionospheric TEC disturbance by November 2004 geomagnetic storm and January 2005 substorm. The mechanisms are applied by using v-SVR learning algorithm which is a regression version of SVM. Our results show that both mechanisms are quiet accurate in learning TEC data. However, novelty detection is more accurate than outliers detection in extracting anomalies related to geomagnetic events. The detected anomalies by outliers detection are mostly related to trend of data, while novelty detection are associated to geomagnetic events. Novelty detection also shows evidence of LSTID during geomagnetic events.

  8. Comparative analysis of GPS-derived TEC estimates and foF2 observations during storm conditions towards the expansion of ionospheric forecasting capabilities over Europe

    NASA Astrophysics Data System (ADS)

    Tsagouri, Ioanna; Belehaki, Anna; Elias, Panagiotis

    2017-04-01

    This paper builts the discussion on the comparative analysis of the variations in the peak electron density at F2 layer and the TEC parameter during a significant number of geomagnetic storm events that occurred in the present solar cycle 24. The ionospheric disturbances are determined through the comparison of actual observations of the foF2 critical frequency and GPS-TEC estimates obtained over European locations with the corresponding median estimates, and they are analysed in conjunction to the solar wind conditions at L1 point that are monitored by the ACE spacecraft. The quantification of the storm impact on the TEC parameter in terms of possible limitations introduced by different TEC derivation methods is carefully addressed.The results reveal similarities and differences in the response of the two parameters with respect to the solar wind drivers of the storms, as well as the local time and the latitude of the observation point. The aforementioned dependences drive the storm-time forecasts of the SWIF model (Solar Wind driven autorgressive model for Ionospheric short-term Forecast), which is operationally implemented in the DIAS system (http://dias.space.noa.gr) and extensively tested in performance at several occassions. In its present version, the model provides alerts and warnings for upcoming ionospheric disturbances, as well as single site and regional forecasts of the foF2 characteristic over Europe up to 24 hours ahead based on the assesment of the solar wind conditions at ACE location. In that respect, the results obtained above support the upgrade of the SWIF's modeling technique in forecasting the storm-time TEC variation within an operational environment several hours in advance. Preliminary results on the evaluation of the model's efficiency in TEC prediction are also discussed, giving special attention in the assesment of the capabilities through the TEC-derivation uncertanties for future discussions.

  9. Response of data-driven artificial neural network-based TEC models to neutral wind for different locations, seasons, and solar activity levels from the Indian longitude sector

    NASA Astrophysics Data System (ADS)

    Sur, D.; Haldar, S.; Ray, S.; Paul, A.

    2017-07-01

    The perturbations imposed on transionospheric signals by the ionosphere are a major concern for navigation. The dynamic nature of the ionosphere in the low-latitude equatorial region and the Indian longitude sector has some specific characteristics such as sharp temporal and latitudinal variation of total electron content (TEC). TEC in the Indian longitude sector also undergoes seasonal variations. The large magnitude and sharp variation of TEC cause large and variable range errors for satellite-based navigation system such as Global Positioning System (GPS) throughout the day. For accurate navigation using satellite-based augmentation systems, proper prediction of TEC under certain geophysical conditions is necessary in the equatorial region. It has been reported in the literature that prediction accuracy of TEC has been improved using measured data-driven artificial neural network (ANN)-based vertical TEC (VTEC) models, compared to standard ionospheric models. A set of observations carried out in the Indian longitude sector have been reported in this paper in order to find the amount of improvement in performance accuracy of an ANN-based VTEC model after incorporation of neutral wind as model input. The variations of this improvement in prediction accuracy with respect to latitude, longitude, season, and solar activity have also been reported in this paper.

  10. Study of Ionospheric TEC from GPS observations and comparisons with IRI and SPIM model predictions in the low latitude anomaly Indian subcontinental region

    NASA Astrophysics Data System (ADS)

    Panda, S. K.; Gedam, S. S.; Rajaram, G.

    2015-04-01

    The present study investigates variation of the ionospheric total electron content (TEC) in the low latitude Indian sub-continental region from the GPS observations and its comparison with the global ionosphere maps (GIMs), standard international reference ionosphere (IRI 2012), and the standard plasmasphere-ionosphere model (SPIM) for the period from November 2011 to October 2012 that corresponds to the progressive phase towards the midst of the solar cycle-24. Observations during quiet period show diurnal maximum of TEC occurring around 14:00-16:00 IST, with relatively broader and longer duration of local maximum at Bangalore and behave reversely towards Delhi. The secondary maximum of TEC was markedly noticeable at Bangalore during the months of March and September, and only in the month of September at Hyderabad and Mumbai. However, the relatively higher TEC during December month than the June is ascribed to the winter anomaly which is more prevalent during the high solar activity periods. The prevailing instability in latitudes of anomaly crest during January 2012 is possibly due to the seasonal variation of lunar tidal effects, modulating the EEJ strength at the equator. The studies covered the period of a strong geomagnetic storm during 6-11 March 2012 (SYM-H: -149 nT) which resulted in positive deviation of GPS-TEC at Bangalore (↑ 20%), Hyderabad (↑ 22%), and Lucknow (↑ 94%) compared to the mean quiet days level. The relatively large deviation of TEC at Lucknow could be attributed to the poleward shifting of the anomaly crest, manifested by enhanced fountain effect at the equator. Studies confirm excellent agreement (80-85%) of GPS-TEC with IGS-GIM at Bangalore and Hyderabad with the exception of the night-time hours (Deviations >50%). However relatively larger deviation of GPS-TEC from GIM-TEC at Delhi could be due to the unavailability of IGS stations in the proximity of the position. Predictions of the SPIM model (extension of IRI up to GPS

  11. 3D tomography of midlatitude sporadic-E in Japan from GNSS-TEC data

    NASA Astrophysics Data System (ADS)

    Muafiry, Ihsan Naufal; Heki, Kosuke; Maeda, Jun

    2018-03-01

    We studied ionospheric irregularities caused by midlatitude sporadic-E ( Es) in Japan using ionospheric total electron content (TEC) data from a dense GNSS array, GEONET, with a 3D (three-dimensional) tomography technique. Es is a thin layer of unusually high ionization that appears at altitudes of 100 km. Here, we studied five cases of Es irregularities in 2010 and 2012, also reported in previous studies, over the Kanto and Kyushu Districts. We used slant TEC residuals as the input and estimated the number of electron density anomalies of more than 2000 small blocks with dimensions of 20-30 km covering a horizontal region of 300 × 500 km. We applied a continuity constraint to stabilize the solution and performed several different resolution tests with synthetic data to assess the accuracy of the results. The tomography results showed that positive electron density anomalies occurred at the E region height, and the morphology and dynamics were consistent with those reported by earlier studies.

  12. Improving Science Teacher Preparation through the APS PhysTEC and NSF Noyce Programs

    NASA Astrophysics Data System (ADS)

    Williams, Tasha; Tyler, Micheal; van Duzor, Andrea; Sabella, Mel

    2013-03-01

    Central to the recruitment of students into science teaching at a school like CSU, is a focus on the professional nature of teaching. The purpose of this focus is twofold: it serves to change student perceptions about teaching and it prepares students to become teachers who value continued professional development and value the science education research literature. The Noyce and PhysTEC programs at CSU place the professional nature of teaching front and center by involving students in education research projects, paid internships, attendance at conferences, and participation in a new Teacher Immersion Institute and a Science Education Journal Reading Class. This poster will focus on specific components of our teacher preparation program that were developed through these two programs. In addition we will describe how these new components provide students with diverse experiences in the teaching of science to students in the urban school district. Supported by the NSF Noyce Program (0833251) and the APS PhysTEC Program.

  13. Modeling magnetic field and TEC signatures of large-amplitude acoustic and gravity waves generated by natural hazard events

    NASA Astrophysics Data System (ADS)

    Zettergren, M. D.; Snively, J. B.; Inchin, P.; Komjathy, A.; Verkhoglyadova, O. P.

    2017-12-01

    Ocean and solid earth responses during earthquakes are a significant source of large amplitude acoustic and gravity waves (AGWs) that perturb the overlying ionosphere-thermosphere (IT) system. IT disturbances are routinely detected following large earthquakes (M > 7.0) via GPS total electron content (TEC) observations, which often show acoustic wave ( 3-4 min periods) and gravity wave ( 10-15 min) signatures with amplitudes of 0.05-2 TECU. In cases of very large earthquakes (M > 8.0) the persisting acoustic waves are estimated to have 100-200 m/s compressional velocities in the conducting ionospheric E and F-regions and should generate significant dynamo currents and magnetic field signatures. Indeed, some recent reports (e.g. Hao et al, 2013, JGR, 118, 6) show evidence for magnetic fluctuations, which appear to be related to AGWs, following recent large earthquakes. However, very little quantitative information is available on: (1) the detailed spatial and temporal dependence of these magnetic fluctuations, which are usually observed at a small number of irregularly arranged stations, and (2) the relation of these signatures to TEC perturbations in terms of relative amplitudes, frequency, and timing for different events. This work investigates space- and time-dependent behavior of both TEC and magnetic fluctuations following recent large earthquakes, with the aim to improve physical understanding of these perturbations via detailed, high-resolution, two- and three-dimensional modeling case studies with a coupled neutral atmospheric and ionospheric model, MAGIC-GEMINI (Zettergren and Snively, 2015, JGR, 120, 9). We focus on cases inspired by the large Chilean earthquakes from the past decade (viz., the M > 8.0 earthquakes from 2010 and 2015) to constrain the sources for the model, i.e. size, frequency, amplitude, and timing, based on available information from ocean buoy and seismometer data. TEC data are used to validate source amplitudes and to constrain

  14. TEC variations over Mediteranean before and during the strong earthquake (M=6.2) of 12th October 2013 in Crete, Greece

    NASA Astrophysics Data System (ADS)

    Contadakis, Michael; Arabelos, Dimitrios; Vergos, Georgios; Spatalas, Spyridon

    2014-05-01

    In this paper the Total Electron Content (TEC) data of 9 Global Positioning System (GPS) stations of the EUREF network, which are being provided by IONOLAB (Turkey), were analysed using Discrete Fourier Analysis in order to investigate the TEC variations over Mediteranean before and during the strong earthquake of 12th of October 2013, Which occur in western of Crete, Greece. In accordance to the results of similar analysis on the occasion of earthquakes in the area (Contadakis et al 2008, 2012a,2012b) the main conclusions of this analysis are the following. (a) TEC oscillations in a broad range of frequencies occur randomly over a broad area of several hundred km from the earthquake and (b) high frequency oscillations (f ≥ 0.0003Hz, periods T ≤ 60m) seems to point to the location of the earthquake with a questionable accuracy but the fractal characteristics of the frequencies distribution, points to the locus of the earthquake with a rather higher accuracy. We conclude that the LAIC mechanism through acoustic or gravity wave could explain this phenomenology. Key words: GPS network, ionospheric total electron content, wavelet analysis References Contadakis, M.E., Arabelos, D.N. G. Asteriadis, S.D. Spatalas and Ch. Pikridas, 2008. TEC variations over the Mediterranean during the seismic activity period of the last quarter of 2005 in the area of Greece, Nat. Hazards Earth Syst. Sci., 8, 1267-1276 M.E. Contadakis, D.N. Arabelos, Ch. Pikridas and S.D. Spatalas, 2012a,TEC variations over Southern Europe before and during the M6.3 Abruzzo earthquake of 6th April 2009, Annals of Geophysics, Vol.55,1, p.83-93 M.E.Contadakis, D.N.Arabelos, and G.Vergos, 2012b, TEC variations over North-western Balkan peninsula before and during the seismic activity of 24th May 2009, EGU GA, Geoph. Res. Abs., Vol. 14, EGU2012-2319-2

  15. Comparative Analysis of Various Aspects of Plateletpheresis on the Fenwal Amicus and Fresenius COM.TEC Cell Separator Instruments.

    PubMed

    Philip, Joseph; Biswas, Amit Kumar; Chatterjee, Tathagata; Mallhi, Rajiv Singh

    2014-01-01

    To compare the Fenwal Amicus and the Fresenius COM.TEC apheresis instruments regarding donor peripheral blood parameters, operational variables of the instruments, and quality control parameters of the product obtained. We performed 100 platelet collections from 100 voluntary donors using the 2 studied devices. We measured platelet count using an automated analyzer and analyzed the activation statuses using a flow cytometer. The median time needed to perform the procedures was significantly longer with the COM.TEC. However, the product we obtained using the Amicus instrument showed higher degrees of platelet-activation. All products we obtained with both instruments had white blood cell counts of less than 5 × 10(6) per bag. We observed no statistical difference regarding collection efficiency and collection rates between the devices. Both instruments collected platelets efficiently, with minimal donor discomfort. Compared with the COM.TEC instrument, the Amicus reached the platelet target yield more quickly; however, it displayed an increase in platelet activation. Copyright© by the American Society for Clinical Pathology (ASCP).

  16. Submillimeter Galaxy Surveys with AzTEC

    NASA Astrophysics Data System (ADS)

    Wilson, Grant W.; Ade, P. A.; Aretxaga, I.; Austermann, J.; Battersby, C.; Bock, J. J.; Glenn, J.; Golwala, S. R.; Haig, D.; Hughes, D. H.; Kang, Y.; Kim, S.; Lowenthal, J.; Mauskopf, P. D.; Perera, T.; Scott, K.; Roberts, C.; Yoon, I.; Yun, M. S.

    2006-06-01

    We describe a recent large scale survey of the Submillimeter Galaxy (SMG) population by AzTEC, a 144 element bolometer camera, on the 15m diameter James Clerk Maxwell Telescope. From November 2005 to February 2006, over 400 hours of telescope time were spent imaging over 1 square degree of sky with an area weighted target sensitivity of 0.7 mJy rms. Several fields with large multi-wavelength data sets were mapped including the Subaru/XMM-Newton Deep Survey field, the Lockmann Hole, GOODS-N, and a subset of the COSMOS field. In addition we mapped fields spanning a wide range of environments including several regions with known mass over-density. Together this represents the largest/deepest survey of the SMG population. Herein we report on the technical details of the surveys, describe the reduction pipeline, and show preliminary results from a subsection of the survey fields.

  17. A method for separating seismo-ionospheric TEC outliers from heliogeomagnetic disturbances by using nu-SVR

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

    Pattisahusiwa, Asis; Liong, The Houw; Purqon, Acep

    Seismo-Ionospheric is a study of ionosphere disturbances associated with seismic activities. In many previous researches, heliogeomagnetic or strong earthquake activities can caused the disturbances in the ionosphere. However, it is difficult to separate these disturbances based on related sources. In this research, we proposed a method to separate these disturbances/outliers by using nu-SVR with the world-wide GPS data. TEC data related to the 26th December 2004 Sumatra and the 11th March 2011 Honshu earthquakes had been analyzed. After analyzed TEC data in several location around the earthquake epicenter and compared with geomagnetic data, the method shows a good result inmore » the average to detect the source of these outliers. This method is promising to use in the future research.« less

  18. VizieR Online Data Catalog: AzTEC/ASTE source catalogue (Aretxaga+, 2011)

    NASA Astrophysics Data System (ADS)

    Aretxaga, I.; Wilson, G. W.; Aguilar, E.; Alberts, S.; Scott, K. S.; Scoville, N.; Yun, M. S.; Austermann, J.; Downes, T. P.; Ezawa, H.; Hatsukade, B.; Hughes, D. H.; Kawabe, R.; Kohno, K.; Oshima, T.; Perera, T. A.; Tamura, Y.; Zeballos, M.

    2013-02-01

    We imaged a 2800 arcmin2 field centred at right ascension RA(J2000.0)=10:00:30.00 and declination DE(J2000.0)=2:14.00 with AzTEC mounted on the 10-m ASTE, located at 4800m in the Atacama Desert of Chile. The survey was carried out from 2008 October 20 to November 30. (1 data file).

  19. Fresenius AS.TEC204 blood cell separator.

    PubMed

    Sugai, Mikiya

    2003-02-01

    Fresenius AS.TEC204 is a third-generation blood cell separator that incorporates the continuous centrifugal separation method and automatic control of the cell separation process. Continuous centrifugation separates cell components according to their specific gravity, and different cell components are either harvested or eliminated as needed. The interface between the red blood cell and plasma is optically detected, and the Interface Control (IFC) cooperates with different pumps, monitors and detectors to harvest required components automatically. The system is composed of three major sections; the Front Panel Unit; the Pump Unit, and the Centrifuge Unit. This unit can be used for a wide variety of clinical applications including collection of platelets, peripheral blood stem cells, bone marrow stem cells, granulocytes, mononuclear cells, and exchange of plasma or red cells, and for plasma treatment.

  20. GNSS derived TEC data ingestion into IRI 2012

    NASA Astrophysics Data System (ADS)

    Migoya-Orué, Yenca; Nava, Bruno; Radicella, Sandro; Alazo-Cuartas, Katy

    2015-04-01

    Experimental vertical total electron content (VTEC) data given by Global Ionospheric Maps (GIM) has been ingested into the IRI version 2012, aiming to obtain grids of effective input parameter values that allow to minimize the difference between the experimental and modeled vertical TEC. Making use of the experience gained with the technique of model adaptation applied to NeQuick (Nava et al., 2005), it has been found possible to compute IRI world grids of effective ionosphere index parameters (IG). The IG grids thus obtained can be interpolated in space and time to calculate with IRI the 3D electron density at any location and also the TEC along any ground-to-satellite ray-path for a given epoch. In this study, the ingestion technique is presented and a posteriori validation, along with an assessment of the capability of the 'ingested' IRI to reproduce the ionosphere day-to-day foF2 variability during disturbed and quiet periods. The foF2 values retrieved are compared with data from about 20 worldwide ionosondes for selected periods of high (year 2000) and moderate to low solar activity (year 2006). It was found that the use of the ingestion scheme enhances the performance of the model when compared with its standard use based on solar activity drivers (R12 and F10.7), especially for high solar activity. As an example, the mean and standard deviation of the differences between experimental and reconstructed F2-peak values for April of year 2000 is 0.09 and 1.28 MHz for ingested IRI, compared to -0.81 and 1.27 MHz (IRI with R12 input) and -0.02 and 1.46 MHz (IRI with F10.7 input).

  1. GPS-TEC of the Ionospheric Disturbances as a Tool for Early Tsunami Warning

    NASA Astrophysics Data System (ADS)

    Kunitsyn, Viacheslav E.; Nesterov, Ivan A.; Shalimov, Sergey L.; Krysanov, Boris Yu.; Padokhin, Artem M.; Rekenthaler, Douglas

    2013-04-01

    Recently, the GPS measurements were used for retrieving the information on the various types of ionospheric responses to seismic events (earthquakes, seismic Rayleigh waves, and tsunami) which generate atmospheric waves propagating up to the ionospheric altitudes where the collisions between the neutrals and charge particles give rise to the motion of the ionospheric plasma. These experimental results can well be used in architecture of the future tsunami warning system. The point is an earlier (in comparison with seismological methods) detection of the ionospheric signal that can indicate the moment of tsunami generation. As an example we consider the two-dimensional distributions of the vertical total electron content (TEC) variations in the ionosphere both close to and far from the epicenter of the Japan undersea earthquake of March 11, 2011 using radio tomographic (RT) reconstruction of high-temporal-resolution (2-minute) data from the Japan and the US GPS networks. Near-zone TEC variations shows a diverging ionospheric perturbation with multi-component spectral composition emerging after the main shock. The initial phase of the disturbance can be used as an indicator of the tsunami generation and subsequently for the tsunami early warning. Far-zone TEC variations reveals distinct wave train associated with gravity waves generated by tsunami. According to observations tsunami arrives at Hawaii and further at the coast of Southern California with delay relative to the gravity waves. Therefore the gravity wave pattern can be used in the early tsunami warning. We support this scenario by the results of modeling with the parameters of the ocean surface perturbation corresponding to the considered earthquake. In addition it was observed in the modeling that at long distance from the source the gravity wave can pass ahead of the tsunami. The work was supported by the Russian Foundation for Basic Research (grants 11-05-01157 and 12-05-33065).

  2. Candida detection system (CAND-TEC) to differentiate between Candida albicans colonization and disease.

    PubMed Central

    Fung, J C; Donta, S T; Tilton, R C

    1986-01-01

    Eighty-three serum specimens from 24 patients infected with Candida albicans were examined for circulating Candida protein antigens with the Candida Detection System (CAND-TEC; Ramco Laboratories, Inc., Houston, Tex.). The medical records of each patient were reviewed for clinical evidence of Candida colonization or disease, predisposing factors for infection, underlying illness, the presence of a contaminated indwelling venous catheter, intravenous amphotericin B therapy, and outcome. Forty-nine serum specimens with antigen titers of 1:2 or less were obtained either from colonized patients or at a time when disseminated disease was not yet clinically suspected. Except for five specimens from two colonized patients, one with a contaminated arterial line, the other specimens with titers of 1:8 or greater (n = 14) were obtained from patients who had been clinically diagnosed and treated for disseminated candidiasis. Serum specimens with titers of 1:4 were often from patients with deep-seated candidal infection but were not uniformly diagnostic; in this situation additional specimens should be tested for Candida antigen titers. Only 1 of 24 serum specimens from patients with no evidence of C. albicans infection had a Candida protein antigen titer of 1:8. With a 1:8 or greater titer as a criterion for dissemination, the sensitivity of the CAND-TEC system was 71%, with a specificity of 98%. If the 1:8 titer for the colonized patient with a contaminated arterial line is not considered a false-positive result, the CAND-TEC sensitivity was 83%. The latex agglutination assay appears to be a useful, rapid, and noninvasive means of laboratory diagnosis of systemic candidiasis. The recovery of C. albicans from at least three body sites may also be a useful predictor of disseminated disease. PMID:3533975

  3. Equatorial ionization anomaly development as studied by GPS TEC and foF2 over Brazil: A comparison of observations with model results from SUPIM and IRI-2012

    NASA Astrophysics Data System (ADS)

    Nogueira, P. A. B.; Abdu, M. A.; Souza, J. R.; Batista, I. S.; Bailey, G. J.; Santos, A. M.; Takahashi, H.

    2013-11-01

    The equatorial ionization anomaly (EIA) development is studied using the total electron content (TEC) observed by the Global Positioning System (GPS) satellites, the F2-layer critical frequency (foF2) as measured by digisondes operated in the Brazilian sector, and by model simulation using the SUPIM (Sheffield University Plasmasphere Ionosphere Model). We have used two indices based on foF2 and TEC to represent the strength of the EIA Southern Anomaly Crest (SAC), which are denoted, respectively, by SAC(foF2) and SAC(TEC). Significant differences in the local time variations of the EIA intensity, as represented by these two indices, are investigated. The observed SAC indices are compared with their values modeled by the SUPIM and also by the International Reference Ionosphere (IRI)-2012. The SUPIM simulations that use the standard E×B plasma drift and neutral air wind models are found to provide acceptable representations of the observed foF2 and TEC, and hence the indices SAC(foF2) and SAC(TEC) during daytime, whereas the IRI-2012 model is not, except during the post-midnight/sunrise hours. It is found that the differences in the local time variations between the SAC(foF2) and SAC(TEC) can be reduced by limiting the TEC integrations in height up to an altitude of 630 km in the SUPIM calculations. It is also found that when the EIA intensity is calculated for an intermediate dip latitude (12°S) the difference between the local time variation patterns of the two corresponding indices in the experimental data and in the SUPIM results is reduced. For the IRI-2012 values, the subequatorial station modification does not appear to have any effect.

  4. Real-time reconstruction of topside ionosphere scale height from coordinated GPS-TEC and ionosonde observations

    NASA Astrophysics Data System (ADS)

    Gulyaeva, Tamara; Poustovalova, Ljubov

    The International Reference Ionosphere model extended to the plasmasphere, IRI-Plas, has been recently updated for assimilation of total electron content, TEC, derived from observations with Global Navigation Satellite System, GNSS. The ionosonde products of the F2 layer peak density (NmF2) and height (hmF2) ensure true electron density maximum at the F2 peak. The daily solar and magnetic indices used by IRI-Plas code are compiled in data files including the 3-hour ap and kp magnetic index from 1958 onward, 12-monthly smoothed sunspot number R12 and Global Electron Content GEC12, daily solar radio flux F10.7 and daily sunspot number Ri. The 3-h ap-index is available in Real Time, RT, mode from GFZ, Potsdam, Germany, daily update of F10.7 is provided by Space Weather Canada service, and daily estimated international sunspot number Ri is provided by Solar Influences Data Analysis Center, SIDC, Belgium. For IRI-Plas-RT operation in regime of the daily update and prediction of the F2 layer peak parameters, the proxy kp and ap forecast for 3 to 24 hours ahead based on data for preceding 12 hours is applied online at http://www.izmiran.ru/services/iweather/. The topside electron density profile of IRI-Plas code is expressed with complementary half-peak density anchor height above hmF2 which corresponds to transition O+/H+ height. The present investigation is focused on reconstruction of topside ionosphere scale height using vertical total electron content (TEC) data derived from the Global Positioning System GPS observations and the ionosonde derived F2 layer peak parameters from 25 observatories ingested into IRI-Plas model. GPS-TEC and ionosonde measurements at solar maximum (September, 2002, and October, 2003) for quiet, positively disturbed, and negatively disturbed days of the month are used to obtain the topside scale height, Htop, representing the range of altitudes from hmF2 to the height where NmF2 decay by e times occurs. Mapping of the F2 layer peak parameters

  5. The dynamics and spectral characteristics of the GPS TEC wave packets excited by the solar terminator

    NASA Astrophysics Data System (ADS)

    Afraimovich, E. L.; Edemsky, I. K.; Voeykov, S. V.; Yasukevich, Y. V.; Zhivetiev, I. V.

    2009-04-01

    The great variety of solar terminator (ST) -linked phenomena in the atmosphere gave rise to a num¬ber of studies on the analysis of ionosphere parameter variations obtained by different ionosphere sounding methods. Main part of experimental data was obtained using methods for analyzing the spectrum of ionosphere parameter variations in separate local points. To identify ST-generated wave disturbances it is necessary to measure the dynamic and spectral characteristics of the wave disturbances and to compare it with spatial-temporal characteristics of ST. Using TEC measurements from the dense network of GPS sites GEONET (Japan), we have obtained the first GPS-TEC image of the space structure of medium-scale traveling wave packets (MS TWP) excited by the solar terminator. We use two known forms of the 2D GPS-TEC image for our presentation of the space structure of ST-generated MS TWP: 1) - the diagram "distance-time"; 2) - the 2D-space distribution of the values of filtered TEC series dI (λ, φ, t) on the latitude φ and longitude λ for each 30-sec TEC counts. We found that the time period and wave-length of ST-generated wave packets are about 10-20 min and 200-300 km, respectively. Dynamic images analysis of dI (λ, φ, t) gives precise estimation of velocity and azimuth of TWP wave front propagation. We use the method of determining velocity of traveling ionosphere disturbances (SADM-GPS), which take into account the relative moving of subionosphere points. We found that the velocity of the TWP phase front, traveling along GEONET sites, varies in accordance with the velocity of the ST line displacement. The space image of MS TWP manifests itself in pronounced anisotropy and high coherence over a long distance of about 2000 km. The TWP wave front extends along the ST line with the angular shift of about 20°. The hypothesis on the connection between the TWP generation and the solar terminator can be tested in the terminator local time (TLT) system: d

  6. Simultaneous ground-satellite observations of daytime traveling ionospheric disturbances over Japan using the GPS-TEC network and the CHAMP satellite

    NASA Astrophysics Data System (ADS)

    Moral, A. C.; Shiokawa, K.; Otsuka, Y.; Liu, H.; Nishioka, M.; Tsugawa, T.

    2017-12-01

    We report results of simultaneous ground-satellite measurements of daytime travelling ionospheric disturbances (TIDs) over Japan by using the GEONET GPS receiver network and the CHAMP satellite. For the two years of 2002 and 2008, we examined GPS measurements of TEC (Total Electron Content) and neutral and electron densities measured by CHAMP satellite. Total of fifteen TID events with clear southward moving structures in the GPS-TEC measurements are found by simultaneous ground-satellite measurements. On 2002, simultaneous events are only observed in January (1 event) and February (4 events). On 2008, ten events are observed around winter months (January (3 events), February (5), March (1), and October (1)). Neutral and electron densities measured by CHAMP show quasi-periodic fluctuations throughout the passages for all events. The CHAMP satellite crossed at least one clear TID phase front for all the events. We fitted a sinusoidal function to both ground and satellite data to obtain the frequencies and phase of the observed variations. We calculated the corresponding phase relationships between TEC variations and neutral and electron densities measured by CHAMP to categorize the events. In the presentations we report correspondence of these TID structures seen in the simultaneous ground-satellite observations by GPS-TEC and CHAMP, and discuss their phase relationship to identify the source of the daytime TIDs and specify how much of the observed variations are showing clear frequencies/or not in the nature at middle latitudes.

  7. Ionospheric disturbances detected by high-resolution GPS-TEC observations after an earthquake and a tornado

    NASA Astrophysics Data System (ADS)

    Tsugawa, Takuya; Otsuka, Yuichi; Saito, Akinori; Ishii, Mamoru; Nishioka, Michi

    Ionospheric disturbances following the 2011 Tohoku earthquake and the 2013 Moore tornado were observed by high-resolution GPS total electron content (TEC) observations using dense GPS receiver networks. After the 2011 Tohoku earthquake, concentric waves with short propagation distance propagated in the radial direction in the propagation velocity of 3,457, 783, 423 m/s for the first, second, third peak, respectively. Following these waves, concentric waves with long propagation distance appeared to propagate at the velocity of 138-288 m/s. In the vicinity of the epicenter, sudden TEC depletions and short-period oscillations with a period of approximately 4 minutes were also observed. The center of these ionospheric variations, termed the "ionospheric epicenter", corresponded to the tsunami source. Comparing to the results of a numerical simulation using non-hydrostatic compressible atmosphere-ionosphere model, the first peak of circular wave would be caused by the acoustic waves generated from the propagating Rayleigh wave. The second and third waves would be caused by atmospheric gravity waves excited in the lower ionosphere due to the acoustic wave propagations from the tsunami source. The fourth and following waves are considered to be caused by the atmospheric gravity waves induced by the wavefronts of traveling tsunami. After the EF5 tornado hit Moore, Oklahoma, USA, on 20 May 2013, clear concentric waves and short-period oscillations were observed. These concentric waves were non-dispersive waves with a horizontal wavelength of approximately 120 km and a period of approximately 13 minutes. They were observed for more than seven hours throughout North America. TEC oscillations with a period of approximately 4 minutes were also observed in the south of Moore for more than eight hours. Comparison between the GPS-TEC observations and the infrared cloud images from the GOES satellite indicates that the concentric waves and the short-period oscillations would be

  8. Evaluation of Hi-Tec Implant Restoration in Mandibular First Molar Region- A Prospective Clinical Study.

    PubMed

    Sreeram, Roopa Rani S; Prasad, L Krishna; Chakravarthi, P Srinivas; Devi, Naga Neelima; Kattimani, Vivekanand S; Sreeram, Sanjay Krishna

    2015-08-01

    Missing teeth lead to loss of structural balance, inefficient function, poor aesthetics and psychological effects on human beings, which needs restoration for normal contour, function and aesthetics. Several natural or synthetic substitutes are being used for replacement of missing tooth since centuries. Implants are the latest modality of replacement. So, the study was aimed to assess clinical success rate of Hi-Tec implant; which is economical and new in market. Results of the study will help clinician for appropriate implant selection. The study included 10 patients from 19 to 31 years and needed restoration of missing mandibular first molar. Restoration had done using Hi Tec Single-tooth implants with metal-ceramic single crown prosthesis after three months of osseointegration. The implants were evaluated clinically (bleeding on probing, probing depth, implant mobility- periotest) and radiographically (marginal bone loss and peri-implant radiolucency) for six years. The observers were blinded for the duration of the study to prevent bias. All the patients had uneventful post-surgical healing. No bleeding on probing, Implant mobility, peri-implant radiolucency with minimal marginal bone loss and constant probing depths were observed well within the normal range during follow-up periods. Two stage single-tooth Hi Tec implant restoration can be used as a successful treatment modality for replacing mandibular first molar in an economic way. However, these results were obtained after 6 years of follow up with a smaller sample size, so long term multi center studies with a larger sample size is recommended for the predictability of success rate conclusively.

  9. Comparison of GPS-TEC measurements with NeQuick2 and IRI model predictions in the low latitude East African region during varying solar activity period (1998 and 2008-2015)

    NASA Astrophysics Data System (ADS)

    Mengistu, E.; Damtie, B.; Moldwin, M. B.; Nigussie, M.

    2018-03-01

    This paper examines the performances of NeQuick2, the latest available IRI-2016, IRI-2012 and IRI-2007 models in describing the monthly and seasonal mean total electron content (TEC) over the East African region. This is to gain insight into the success of the various model types and versions at characterizing the ionosphere within the equatorial ionization anomaly. TEC derived from five Global Positioning System (GPS) receivers installed at Addis Ababa (ADD, 5.33°N, 111.99°E Geog.), Asab (ASAB, 8.67°N, 116.44°E Geog.), Ambo (ABOO, 5.43°N, 111.05°E Geog.), Nairobi (RCMN, -4.48°N, 108.46°E Geog.) and Nazret (NAZR, 4.78°N, 112.43°E Geog.), are compared with the corresponding values computed using those models during varying solar activity period (1998 and 2008-2015). We found that different models describe the equatorial and anomaly region ionosphere best depending on solar cycle, season and geomagnetic activity levels. Our results show that IRI-2016 is the best model (compared to others in terms of discrepancy range) in estimating the monthly mean GPS-TEC at NAZR, ADD and RCMN stations except at ADD during 2008 and 2012. It is also found that IRI-2012 is the best model in estimating the monthly mean TEC at ABOO station in 2014. IRI show better agreement with observations during June solstice for all the years studied at ADD except in 2012 where NeQuick2 better performs. At NAZR, NeQuick2 better performs in estimating seasonal mean GPS-TEC during 2011, while IRI models are best during 2008-2009. Both NeQuick2 and IRI models underestimate measured TEC for all the seasons at ADD in 2010 but overestimate at NAZR in 2009 and RCMN in 2008. The periodic variations of experimental and modeled TEC have been compared with solar and geomagnetic indices at ABOO and ASAB in 2014 and results indicate that the F10.7 and sunspot number as indices of solar activity seriously affects the TEC variations with periods of 16-32 days followed by the geomagnetic activity on

  10. 76 FR 73683 - Whirlpool Corporation, Including On-Site Leased Workers From Career Solutions TEC Staffing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-29

    ..., Inc., Fort Smith, AR; Amended Certification Regarding Eligibility To Apply for Worker Adjustment... Career Solutions TEC Staffing, Fort Smith, Arkansas. The workers are engaged in the production of...., Prodriver, and Arkansas Warehouse, Inc. were employed on-site at the Fort Smith, Arkansas location of...

  11. 76 FR 72978 - Whirlpool Corporation Including On-Site Leased Workers From Career Solutions TEC Staffing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-28

    ..., TEK Systems, Penske Logistics, Eurest, and Canteen, Fort Smith, AR; Amended Certification Regarding... Corporation, including on-site leased workers from Career Solutions TEC Staffing, Fort Smith, Arkansas. The... Corporation, TEK Systems, Penske Logistics, Eurest, and Canteen were employed on-site at the Fort Smith...

  12. Study of ionospheric precursors using GPS and GIM-TEC data related to earthquakes occurred on 16 April and 24 September, 2013 in Pakistan region

    NASA Astrophysics Data System (ADS)

    Pundhir, Devbrat; Singh, Birbal; Singh, O. P.; Gupta, Saral Kumar; Karia, S. P.; Pathak, K. N.

    2017-11-01

    In this paper, we have examined the diurnal variations of GPS-TEC observed at two Indian stations of Agra (27.2°N, 78°E) and Surat (21.16°N, 72.78°E) and global ionospheric maps data (GIM-TEC) for the months of April and September 2013 in search of ionospheric precursors of three major earthquakes (M > 6.5) that occurred in these months. The well-established quartile based statistical technique is adopted for the analysis of TEC data. The results show two kinds of anomalies, one in which simultaneous enhancements in TEC occurred in the three sets of data, 1-9 days and 3 days before the main shock in the two months respectively, and another in which anomalies occurred 15 days before in April, and 21 days before in September at Surat respectively. The depletions have also been found in three data sets but they are not significant. These anomalies are unlikely be influenced by geomagnetic parameters due to quiet magnetic conditions. The effect of also solar activity have also been considered and examined very precisely. The results are interpreted in terms of Lithosphere-Atmosphere-Ionosphere coupling (LAIC) mechanisms available in the literature.

  13. New LMT High Resolution Imaging and CO Spectroscopic Studies of the Brightest AzTEC 1.1mm Sources

    NASA Astrophysics Data System (ADS)

    Yun, Min S.; Aretxaga, Itziar; Hughes, David; Montana, A.; Pope, A.; Bruzual, Gustavo; Ferrusca, D.; Rosa Gonzalez, D.; Sanchez-Arguelles, D.; Narayanan, G.; Wilson, Grant; Gim, Hansung; Ibarra, H.; Mo, H.; Lowenthal, James; Zavala, J.; Carrasco, L.; Chavez, M.; Valazquez, M.; Zeballos, M.; Vega, O.; Schloerb, P.; Cybulsky, J. R.; Casey, Caitlin M.; Tang, Y.

    2015-08-01

    A substantial population of quiescent galaxies with stellar masses exceeding 10 billion solar masses have been found to z~4, suggesting a rapid formation and quenching of massive galaxies at z~6 or earlier. The submillimeter bright galaxies (SMGs) with SFR > 100-1000 solar masses per year represent natural candidates for the progenitor systems undergoing an epoch of rapid formation and cessation of stellar mass build up. Many of the most luminous SMGs are also extremely red and faint in the optical, suggesting a high redshift and are beyond the reach of the current optical spectroscopic redshift surveys. There is also a growing concern that these most luminous SMGs may be blends of several unrelated sources as a result of a poor angular resolution of the existing surveys (18" & 28" for the AzTEC 1.1mm surveys on JCMT and ASTE, respectively). We have obtained new 8" resolution AzTEC images of 40 brightest AzTEC sources previously found in the GOODS and COSMOS fields using the Large Millimeter Telescope (LMT) to examine the multiplicity question and for the identification of multi-wavelength counterparts. We have also conducted a CO redshift survey using the Redshift Search Receiver on the LMT. We will report the results of these analysis and several new CO redshifts.

  14. Evaluation of an Internally Controlled Multiplex Tth Endonuclease Cleavage Loop-Mediated Isothermal Amplification (TEC-LAMP) Assay for the Detection of Bacterial Meningitis Pathogens.

    PubMed

    Higgins, Owen; Clancy, Eoin; Cormican, Martin; Boo, Teck Wee; Cunney, Robert; Smith, Terry J

    2018-02-09

    Bacterial meningitis infection is a leading global health concern for which rapid and accurate diagnosis is essential to reduce associated morbidity and mortality. Loop-mediated isothermal amplification (LAMP) offers an effective low-cost diagnostic approach; however, multiplex LAMP is difficult to achieve, limiting its application. We have developed novel real-time multiplex LAMP technology, TEC-LAMP, using Tth endonuclease IV and a unique LAMP primer/probe. This study evaluates the analytical specificity, limit of detection (LOD) and clinical application of an internally controlled multiplex TEC-LAMP assay for detection of leading bacterial meningitis pathogens: Streptococcus pneumoniae , Neisseria meningitidis and Haemophilus influenzae . Analytical specificities were established by testing 168 bacterial strains, and LODs were determined using Probit analysis. The TEC-LAMP assay was 100% specific, with LODs for S. pneumoniae , N. meningitidis and H. influenzae of 39.5, 17.3 and 25.9 genome copies per reaction, respectively. Clinical performance was evaluated by testing 65 archived PCR-positive samples. Compared to singleplex real-time PCR, the multiplex TEC-LAMP assay demonstrated diagnostic sensitivity and specificity of 92.3% and 100%, respectively. This is the first report of a single-tube internally controlled multiplex LAMP assay for bacterial meningitis pathogen detection, and the first report of Tth endonuclease IV incorporation into nucleic acid amplification diagnostic technology.

  15. TEC variations over the Mediterranean before and during the strong earthquake (M = 6.5) of 12th October 2013 in Crete, Greece

    NASA Astrophysics Data System (ADS)

    Contadakis, M. E.; Arabelos, D. N.; Vergos, G.; Spatalas, S. D.; Skordilis, M.

    In this paper, the total electron content (TEC) data from eight global positioning system (GPS) stations of the EUREF network, provided by IONOLAB (Turkey), were analyzed using discrete Fourier analysis to investigate the TEC variations over the Mediterranean before and during the strong earthquake of 12th October 2013, which occurred west of Crete, Greece. In accordance with the results of similar analyses in the area, the main conclusions of this study are the following: (a) TEC oscillations in a broad range of frequencies occur randomly over an area of several hundred km from the earthquake and (b) high frequency oscillations (f ⩾ 0.0003 Hz, periods T ⩽ 60 m) may point to the location of the earthquake with questionable accuracy. The fractal characteristics of the frequency distribution may point to the locus of the earthquake with higher accuracy. We conclude that the lithosphere-atmosphere-ionosphere coupling (LAIC) mechanism through acoustic or gravity waves could explain this phenomenology.

  16. A statistical investigation of z test and ROC curve on seismo-ionospheric anomalies in TEC associated earthquakes in Taiwan during 1999-2014

    NASA Astrophysics Data System (ADS)

    Shih, A. L.; Liu, J. Y. G.

    2015-12-01

    A median-based method and a z test are employed to find characteristics of seismo-ionospheric precursor (SIP) of the total electron content (TEC) in global ionosphere map (GIM) associated with 129 M≥5.5 earthquakes in Taiwan during 1999-2014. Results show that both negative and positive anomalies in the GIM TEC with the statistical significance of the z test appear few days before the earthquakes. The receiver operating characteristic (ROC) curve is further applied to see whether the SIPs exist in Taiwan.

  17. A global picture of ionospheric slab thickness derived from GIM TEC and COSMIC radio occultation observations

    NASA Astrophysics Data System (ADS)

    Huang, He; Liu, Libo; Chen, Yiding; Le, Huijun; Wan, Weixing

    2016-01-01

    The ionospheric equivalent slab thickness (EST), defined as the ratio of total electron content (TEC) to F2 layer peak electron density (NmF2), describes the thickness of the ionospheric profile. In this study, we retrieve EST from TEC data obtained from Global Ionospheric Map (GIM) and NmF2 retrieved from Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) ionospheric radio occultation data. The diurnal, seasonal, and solar activity variations of global EST are analyzed as the excellent spatial coverage of GIM and COSMIC data. During solstices, daytime EST in the summer hemisphere is larger than that in the winter hemisphere, except in some high-latitude regions, and the reverse is true for the nighttime EST. The peaks of EST often appear at 0400 local time. The presunrise enhancement in EST appears in all seasons, while the postsunset enhancement in EST is not readily observed in equinox. Both enhancements are attributed to the more remarkable electron density decay of NmF2 compared to that of TEC. The dependence of EST on solar activity is related to the inconsistent solar activity dependences of electron density at different altitudes. Furthermore, it is interesting that EST is enhanced from 0° to 120°E in longitude and 30° to 75°S in latitude during nighttime, just to the east of Weddell Sea Anomaly, during equinox and the Southern Hemisphere summer. This phenomenon is supposed to be related to the effects of geomagnetic declination-related plasma vertical drifts.

  18. Evaluation of an Internally Controlled Multiplex Tth Endonuclease Cleavage Loop-Mediated Isothermal Amplification (TEC-LAMP) Assay for the Detection of Bacterial Meningitis Pathogens

    PubMed Central

    Clancy, Eoin; Cormican, Martin; Boo, Teck Wee; Cunney, Robert

    2018-01-01

    Bacterial meningitis infection is a leading global health concern for which rapid and accurate diagnosis is essential to reduce associated morbidity and mortality. Loop-mediated isothermal amplification (LAMP) offers an effective low-cost diagnostic approach; however, multiplex LAMP is difficult to achieve, limiting its application. We have developed novel real-time multiplex LAMP technology, TEC-LAMP, using Tth endonuclease IV and a unique LAMP primer/probe. This study evaluates the analytical specificity, limit of detection (LOD) and clinical application of an internally controlled multiplex TEC-LAMP assay for detection of leading bacterial meningitis pathogens: Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae. Analytical specificities were established by testing 168 bacterial strains, and LODs were determined using Probit analysis. The TEC-LAMP assay was 100% specific, with LODs for S. pneumoniae, N. meningitidis and H. influenzae of 39.5, 17.3 and 25.9 genome copies per reaction, respectively. Clinical performance was evaluated by testing 65 archived PCR-positive samples. Compared to singleplex real-time PCR, the multiplex TEC-LAMP assay demonstrated diagnostic sensitivity and specificity of 92.3% and 100%, respectively. This is the first report of a single-tube internally controlled multiplex LAMP assay for bacterial meningitis pathogen detection, and the first report of Tth endonuclease IV incorporation into nucleic acid amplification diagnostic technology. PMID:29425124

  19. A 1.1mm AzTEC Survey Tracing Accelerated Galaxy Formation Towards a Protocluster at z 3.8

    NASA Astrophysics Data System (ADS)

    Hughes, David H.; Montana, A.; Aretxaga, I.; Plionis, M.; Porras, A.; Wagg, J.; Gaztanaga, E.; Huang, J.; Fazio, G.; Wilson, G.; Yun, M.; Lowenthal, J.; Perera, T.; Austermann, J.; Scott, K.; Dunlop, J.; Ivison, R.; Stevens, J.; Smail, I.; Appleton, P.

    2006-12-01

    Aztec has recently conducted a sensitive, wide-area (300 sq. Armin's) continuum survey at 1.1mm using the 15-m James Clerk Maxwell Telescope towards 4C41.17, a powerful high-redshift (z 3.8) radio galaxy. These Aztec data, which cover an area >40 times larger than our previous SCUBA survey, reveal a significant over-density of luminous, massive dust-enshrouded galaxies, compared to the results from lower-redshift blank-field sub-mm surveys. One natural interpretation of these new AzTEC data is that the over-density is tracing a large (5 x 5 Mpc) "proto-cluster" structure at z 3.8 associated with the environment of 4C41.17, within which the formation of ultra-luminous starburst galaxies (with rest-frame FIR luminosities >5 x 1012 Lsun or SFRs > 500 Msun/yr) is taking place at an accelerated rate. Proving the physical association of these massive optically-faint starbursts with the environment of this high-z AGN, and not with the blank-field sub-mm population, for which 50% of the population lies at 1.9 < z < 2.9, remains an outstanding problem. In this presentation we will describe the AzTEC survey, the empirical evidence for this protocluster structure in the early universe, and the planned multi-wavelength follow-up observations of the brightest AzTEC sources towards 4C41.17 that may demonstrate that we are witnessing accelerated galaxy formation, via an increased rate of merging gas-rich galaxies within a rapidly-developing gravitational potential. AzTEC is one of the suite of instruments destined for the 50-m Large Millimeter Telescope (LMT). We will conclude this presentation with a summary of future LMT observations that will trace the evolution of obscured starformation in the dynamic environments towards a significant sample of intermediate and high-z powerful AGN with greater sensitivity and spatial resolution.

  20. Firefly Algorithm in detection of TEC seismo-ionospheric anomalies

    NASA Astrophysics Data System (ADS)

    Akhoondzadeh, Mehdi

    2015-07-01

    Anomaly detection in time series of different earthquake precursors is an essential introduction to create an early warning system with an allowable uncertainty. Since these time series are more often non linear, complex and massive, therefore the applied predictor method should be able to detect the discord patterns from a large data in a short time. This study acknowledges Firefly Algorithm (FA) as a simple and robust predictor to detect the TEC (Total Electron Content) seismo-ionospheric anomalies around the time of the some powerful earthquakes including Chile (27 February 2010), Varzeghan (11 August 2012) and Saravan (16 April 2013). Outstanding anomalies were observed 7 and 5 days before the Chile and Varzeghan earthquakes, respectively and also 3 and 8 days prior to the Saravan earthquake.

  1. Comparison of COSMIC RO Data with European Digisondes and GPS TEC measurements

    NASA Astrophysics Data System (ADS)

    Zakharenkova, Irina; Krypiak-Gregorczyk, Anna; Shagimuratov, Irk; Krankowski, Andrzej; Lagovsky, Anatoly

    variation of NmF2 for the considered seasons depending on day-time and night-time conditions. Also it was analyzed the total elec-tron content values calculated for the nearest ground-based GPS stations located in European region. To compare GPS TEC with RO and ionosondes' data these profiles were integrated. In general bottom parts of COSMIC and ionosondes' data are in a rather good agreement while the topside can be varied greatly that is the evidence of difference in the topside parts of these profiles. GPS TEC values are greater than COSMIC and ionosondes' data as TEC contains IEC and PEC. This procedure can be useful to estimate the impact of PEC into TEC. Results of the given comparisons can be important to validate the reliability of the COSMIC iono-spheric observations using the RO technique. We acknowledge the Taiwan's National Space Organization (NSPO) and the University Corporation for Atmospheric Research (UCAR) for providing the COSMIC Data. We are grateful to European Digital Upper Atmosphere Server (DIAS) for providing the ionosondes' products and to International GNSS Service (IGS) for GPS Data.

  2. 75 FR 77665 - Whirlpool Corporation, Including On-Site Leased Workers From Career Solutions TEC Staffing and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-13

    ..., Including On-Site Leased Workers From Career Solutions TEC Staffing and Andrews International, Fort Smith... Staffing, Fort Smith, Arkansas. The notice was published in the Federal Register on October 25, 2010 (75 FR... reports that workers leased from Andrews International were employed on-site at the Fort Smith, Arkansas...

  3. A comparison of TEC fluctuations and scintillations at Ascension Island

    NASA Astrophysics Data System (ADS)

    Basu, S.; Groves, K. M.; Quinn, J. M.; Doherty, P.

    1999-11-01

    With increasing reliance on space-based platforms for global navigation and communication, concerns about the impact of ionospheric scintillation on these systems have become a high priority. Recently, the Air Force Research Laboratory (AFRL) performed amplitude scintillation measurements of L1 (1.575 MHz) signals from GPS satellites at Ascension Island (14.45° W, 7.95° S; magnetic latitude 16° S) during February-April, 1998, to compare amplitude scintillations with fluctuations of the total electron content (TEC). Ascension Island is located in the South Atlantic under the southern crest of the equatorial anomaly of F2 ionization where scintillations will be much enhanced during the upcoming solar maximum period. Ascension Island is included in the global network of the International GPS Service (IGS) and the GPS receivers in this network report the carrier to noise (C/N) ratio, the dual frequency carrier phase and pseudorange data at 30-s intervals. Such data with a sampling interval of 30 s were analyzed to determine TEC, the rate of change of TEC (ROT) and also ROTI, defined as the standard deviation of ROT. The spatial scale of ROTI, sampled at 30 s interval, will correspond to 6 km when the vector sum of the ionospheric projection of the satellite velocity and the irregularity drift orthogonal to the propagation path is of the order of 100 m/s. On the other hand, the scale-length of the amplitude scintillation index corresponds to the Fresnel dimension which is about 400 m for the GPS L1 frequency and an ionospheric height of 400 km. It is shown that, in view of the co-existence of large and small scale irregularities in equatorial irregularity structures, during the early evening hours, and small magnitude of irregularity drifts, ROTI measurements can be used to predict the presence of scintillation causing irregularities. The quantitative relationship between ROTI and S4, however, varies considerably due to variations of the ionospheric projection of the

  4. Inversion of the perturbation GPS-TEC data induced by tsunamis in order to estimate the sea level anomaly.

    NASA Astrophysics Data System (ADS)

    Rakoto, Virgile; Lognonné, Philippe; Rolland, Lucie; Coïsson, Pierdavide; Drilleau, Mélanie

    2017-04-01

    Large underwater earthquakes (Mw > 7) can transmit part of their energy to the surrounding ocean through large sea-floor motions, generating tsunamis that propagate over long distances. The forcing effect of tsunami waves on the atmosphere generate internal gravity waves which produce detectable ionospheric perturbations when they reach the upper atmosphere. Theses perturbations are frequently observed in the total electron content (TEC) measured by the multi-frequency Global navigation Satellite systems (GNSS) data (e.g., GPS,GLONASS). In this paper, we performed for the first time an inversion of the sea level anomaly using the GPS TEC data using a least square inversion (LSQ) through a normal modes summation modeling technique. Using the tsunami of the 2012 Haida Gwaii in far field as a test case, we showed that the amplitude peak to peak of the sea level anomaly inverted using this method is below 10 % error. Nevertheless, we cannot invert the second wave arriving 20 minutes later. This second wave is generaly explain by the coastal reflection which the normal modeling does not take into account. Our technique is then applied to two other tsunamis : the 2006 Kuril Islands tsunami in far field, and the 2011 Tohoku tsunami in closer field. This demonstrates that the inversion using a normal mode approach is able to estimate fairly well the amplitude of the first arrivals of the tsunami. In the future, we plan to invert in real the TEC data in order to retrieve the tsunami height.

  5. Temporal evolution of the EIA along 95°E as obtained from GNSS TEC measurements and SAMI3 model

    NASA Astrophysics Data System (ADS)

    Kakoti, Geetashree; Kalita, Bitap Raj; Hazarika, Rumajyoti; Bhuyan, Pradip Kumar; Sharma, Sanjay; Tiwari, Ramesh Chandra

    2018-06-01

    The total electron content (TEC) derived from GNSS measurements at a trans-hemispheric meridional chain of ground stations around 95°E longitude are used to study the quiet time inter-hemispheric structure and dynamics of the equatorial ionization anomaly (EIA) during the period March 2015 to February 2016. The stations are Dibrugarh (27.5°N, 95°E, 43° dip), Kohima (25.6°N, 94.1°E, 39° dip), Aizawl (23.7°N, 92.8°E, 36° dip), Port Blair (11.63°N, 92.71°E, 9° dip) and Cocos Islands (12.2°S, 96.8°E, 43° dip). The observation shows that the northern crest of the EIA lies in the south of 23°N (Aizawl) in all seasons but recedes further south towards the equator during December solstice. The largest poleward expansion of the northern (southern) EIA is observed in the March equinox (December solstice). The equinoctial and hemispherical asymmetry of TEC is noted. The winter anomaly is observed in the northern hemisphere but not in the southern hemisphere. The highest midday TEC over any station is observed in the March equinox. The TEC in southern summer (December solstice) is significantly higher than that in the northern summer (June solstice). The observed northern EIA contracts equatorward in the postsunset period of solstice but the southern EIA persists late into the midnight in the December solstice. The asymmetry may be attributed to the different geographic location of the magnetically conjugate stations. The SAMI3 simulations broadly capture the EIA structure and the inter-hemispheric asymmetry during solstices. The difference between observations and the SAMI3 is higher in March equinox and December solstice. The higher E × B vertical drift in the 90-100°E sector and the large geographic-geomagnetic offset in observing stations may have contributed to the observed differences.

  6. Thermal and TEC anomalies detection using an intelligent hybrid system around the time of the Saravan, Iran, (Mw = 7.7) earthquake of 16 April 2013

    NASA Astrophysics Data System (ADS)

    Akhoondzadeh, M.

    2014-02-01

    A powerful earthquake of Mw = 7.7 struck the Saravan region (28.107° N, 62.053° E) in Iran on 16 April 2013. Up to now nomination of an automated anomaly detection method in a non linear time series of earthquake precursor has been an attractive and challenging task. Artificial Neural Network (ANN) and Particle Swarm Optimization (PSO) have revealed strong potentials in accurate time series prediction. This paper presents the first study of an integration of ANN and PSO method in the research of earthquake precursors to detect the unusual variations of the thermal and total electron content (TEC) seismo-ionospheric anomalies induced by the strong earthquake of Saravan. In this study, to overcome the stagnation in local minimum during the ANN training, PSO as an optimization method is used instead of traditional algorithms for training the ANN method. The proposed hybrid method detected a considerable number of anomalies 4 and 8 days preceding the earthquake. Since, in this case study, ionospheric TEC anomalies induced by seismic activity is confused with background fluctuations due to solar activity, a multi-resolution time series processing technique based on wavelet transform has been applied on TEC signal variations. In view of the fact that the accordance in the final results deduced from some robust methods is a convincing indication for the efficiency of the method, therefore the detected thermal and TEC anomalies using the ANN + PSO method were compared to the results with regard to the observed anomalies by implementing the mean, median, Wavelet, Kalman filter, Auto-Regressive Integrated Moving Average (ARIMA), Support Vector Machine (SVM) and Genetic Algorithm (GA) methods. The results indicate that the ANN + PSO method is quite promising and deserves serious attention as a new tool for thermal and TEC seismo anomalies detection.

  7. Using Paraffin PCM, Cryogel and TEC to Maintain Comet Surface Sample Cold from Earth Approach Through Retrieval

    NASA Technical Reports Server (NTRS)

    Choi, Michael K.

    2017-01-01

    An innovative thermal design concept to maintain comet surface samples cold (for example, 263 degrees Kelvin, 243 degrees Kelvin or 223 degrees Kelvin) from Earth approach through retrieval is presented. It uses paraffin phase change material (PCM), Cryogel insulation and thermoelectric cooler (TEC), which are commercially available.

  8. Comparison of spot esculin hydrolysis with the PathoTec strip test for rapid differentiation of anaerobic bacteria.

    PubMed Central

    Qadri, S M; Johnson, S; Smith, J C; Zubairi, S; Gillum, R L

    1981-01-01

    The ability of several anaerobic bacteria to hydrolyze esculin to esculetin is used by clinical microbiologists and taxonomists in the differentiation and identification of both gram-positive and gram-negative microorganisms. Conventional methods used for determining esculin hydrolysis by anaerobic bacteria require 24 to 48 h for completion. In this paper we evaluate two procedures which yield rapid results. A total of 738 anaerobic bacteria were used in this study. A total of 99% of the esculin-hydrolyzing anaerobic bacteria gave positive results with the spot test in 1 h, whereas the other test method, the PathoTec strip test (General Diagnostics, Morris Plains, N.J.), required 4 h for 96% of the strains tested to yield positive reactions. Both tests showed a 100% specificity when compared with the standard broth test and are easy to perform, accurate, and economical. The spot test is superior to the PathoTec strip test in yielding results more rapidly. PMID:7016896

  9. A Comparative Study of the Ionospheric TEC Measurements Using Global Ionospheric Maps of GPS, TOPEX Radar and the Bent Model

    NASA Technical Reports Server (NTRS)

    Ho, C.; Wilson, B.; Mannucci, A.; Lindqwister, U.; Yuan, D.

    1997-01-01

    Global ionospheric mapping (GIM) is a new, emerging technique for determining global ionospheric TEC (total electron content) based on measurements from a worldwide network of Global Positioning System (GPS) receivers.

  10. Ionospheric response to the 17-18 March 2015 geomagnetic storm as seen from multiple TEC and NmF2 measurements along 100°E

    NASA Astrophysics Data System (ADS)

    Bhuyan, Pradip; Yokoyama, Tatsuhiro; Kalita, Bitap Raj; Seemala, G. K.; Hazarika, Rumajyoti; Komolmis, Tharadol; Yatini, Clara; Chakrabarty, Dibyendu; Supnithi, Pornchai

    2016-07-01

    The response of the ionosphere along 100°E to the strong geomagnetic storm of 17-18 March 2015 has been investigated combining TEC and NmF2 data from multiple stations spanning low latitudes in the northern and southern hemispheres to the equator. The GPS TEC data measured over Dibrugarh (27.4°N, 95°E), Kohima (25.6°N, 94.1°E) and Ahmedabad (23.0°N, 72.5°E) and NmF2 measured along a chain of ionosonde stations Dibrugarh (27.5°N, 95°E), Chiang Mai (18.76ºN, 98.93ºE), Chumphon (10.72ºN,99.37ºE), Kototabang (0.2ºS,100.32ºE) and Cocos Island (12.2ºS,96.8ºE ) were used to examine the signature of the storm around the low-mid latitude ionosphere in this sector. Nearly similar TEC variation has been observed over Dibrugarh and Kohima located at the northern edge of the EIA. The maximum TEC on 18 March over Dibrugarh and Kohima was reduced by more than ~80 TECU compared to that on the geomagnetically quiet day of 16 March 2015. In contrast to the substantial reduction in TEC over ~100°E TEC from the ~75°E longitude station Ahmedabad showed insignificant variations on the same day. Strong reduction in NmF2 at the crest of the anomaly in both northern and southern hemisphere (Dibrugarh, Ching Mai and Cocos Island) and enhancement near the equator (Cumphon and Kototbang) has been observed. The O/N2 ratio as obtained from the TIMED/GUVI reduced substantially along 100°E on 18 March compared to other longitude sectors. Equatorward meridional winds depleted the ionization at the crest region and enhanced the same near the equator. No L band scintillation was observed in the evening of 17 March at Dibrugarh and Kohima indicating absence of F region irregularity along this longitude while strong scintillations were observed at 75°E. The reversal of the IMF Bz from southward to northward direction in the dusk to evening sector inhibited the growth of the irregularity due to reversal of the PPEF at 100°E while the PPEF favoured generation and growth of Spread F

  11. Detection of Natural Hazards Generated TEC Perturbations and Related New Applications

    NASA Astrophysics Data System (ADS)

    Komjathy, A.; Yang, Y.; Langley, R. B.

    2013-12-01

    Natural hazards, including earthquakes, volcanic eruptions, and tsunamis, have been significant threats to humans throughout recorded history. The Global Positioning System satellites have become primary sensors to measure signatures associated with such natural hazards. These signatures typically include GPS-derived seismic deformation measurements, co-seismic vertical displacements, and real-time GPS-derived ocean buoy positioning estimates. Another way to use GPS observables is to compute the ionospheric total electron content (TEC) to measure and monitor post-seismic ionospheric disturbances caused by earthquakes, volcanic eruptions, and tsunamis. Research at the University of New Brunswick (UNB) laid the foundations to model the three-dimensional ionosphere at NASA's Jet Propulsion Laboratory by ingesting ground- and space-based GPS measurements into the state-of-the-art Global Assimilative Ionosphere Modeling (GAIM) software. As an outcome of the UNB and NASA research, new and innovative GPS applications have been invented including the use of ionospheric measurements to detect tiny fluctuations in the GPS signals between the spacecraft and GPS receivers caused by natural hazards occurring on or near the Earth's surface. This continuing research is expected to provide early warning for tsunamis, earthquakes, volcanic eruptions, and meteor impacts, for example, using GPS and other global navigation satellite systems. We will demonstrate new and upcoming applications including recent natural hazards and artificial explosions that generated TEC perturbations to perform state-of-the-art imaging and modeling of earthquakes, tsunamis and meteor impacts. By studying the propagation properties of ionospheric perturbations generated by natural hazards along with applying sophisticated first-principles physics-based modeling, we are on track to develop new technologies that can potentially save human lives and minimize property damage.

  12. Characteristics of Total Electron Content (TEC) observed from a chain of stations near the northern crest of the Equatorial Ionization Anomaly (EIA) along 88.5°E meridian in India

    NASA Astrophysics Data System (ADS)

    Paul, K. S.; Das, A.; Ray, S.; Paul, A.

    2016-01-01

    The equatorial ionosphere presents some of the highest TEC values in the world coupled with observations of periodic structures. Total Electron Content (TEC) and scintillation data were analyzed from a chain of stations Calcutta (22.58°N, 88.38°E geographic; 32°N magnetic dip), Baharampore (24.09°N, 88.25°E geographic; 35°N magnetic dip) and Farakka (24.79°N, 87.89°E geographic; 36.04°N magnetic dip) situated almost same meridian (88.5°E) during September 2011 and March-April 2012 for elevation greater than 20° so that the ionosphere can be tracked from the 15.50°N south of Calcutta to 31.80°N north of Farakka. Periodic variation of TEC was noticed before TEC bite out, predominantly within a particular latitudinal swath (19°N ‒26°N) along 88.5°E meridian. No periodic structures were observed over the magnetic equator during the observation period on ionosonde records from the magnetic equator station Trivandrum and COSMIC, GRACE and C/NOFS electron density measurements. The present paper reports, perhaps for the first time from the Indian longitude sector, confinement of such periodic structures in TEC primarily within a latitude swath of 19.00-26.00 °N almost along the same longitude of 88.5 °E.

  13. Genetic algorithm for TEC seismo-ionospheric anomalies detection around the time of the Solomon (Mw = 8.0) earthquake of 06 February 2013

    NASA Astrophysics Data System (ADS)

    Akhoondzadeh, M.

    2013-08-01

    On 6 February 2013, at 12:12:27 local time (01:12:27 UTC) a seismic event registering Mw 8.0 struck the Solomon Islands, located at the boundaries of the Australian and Pacific tectonic plates. Time series prediction is an important and widely interesting topic in the research of earthquake precursors. This paper describes a new computational intelligence approach to detect the unusual variations of the total electron content (TEC) seismo-ionospheric anomalies induced by the powerful Solomon earthquake using genetic algorithm (GA). The GA detected a considerable number of anomalous occurrences on earthquake day and also 7 and 8 days prior to the earthquake in a period of high geomagnetic activities. In this study, also the detected TEC anomalies using the proposed method are compared to the results dealing with the observed TEC anomalies by applying the mean, median, wavelet, Kalman filter, ARIMA, neural network and support vector machine methods. The accordance in the final results of all eight methods is a convincing indication for the efficiency of the GA method. It indicates that GA can be an appropriate non-parametric tool for anomaly detection in a non linear time series showing the seismo-ionospheric precursors variations.

  14. An AzTEC 1.1mm survey of the GOODS-N field - II. Multiwavelength identifications and redshift distribution

    NASA Astrophysics Data System (ADS)

    Chapin, Edward L.; Pope, Alexandra; Scott, Douglas; Aretxaga, Itziar; Austermann, Jason E.; Chary, Ranga-Ram; Coppin, Kristen; Halpern, Mark; Hughes, David H.; Lowenthal, James D.; Morrison, Glenn E.; Perera, Thushara A.; Scott, Kimberly S.; Wilson, Grant W.; Yun, Min S.

    2009-10-01

    We present results from a multiwavelength study of 29 sources (false detection probabilities <5 per cent) from a survey of the Great Observatories Origins Deep Survey-North (GOODS-N) field at 1.1mm using the Astronomical Thermal Emission Camera (AzTEC). Comparing with existing 850μm Submillimetre Common-User Bolometer Array (SCUBA) studies in the field, we examine differences in the source populations selected at the two wavelengths. The AzTEC observations uniformly cover the entire survey field to a 1σ depth of ~1mJy. Searching deep 1.4GHz Very Large Array (VLA) and Spitzer 3-24μm catalogues, we identify robust counterparts for 21 1.1mm sources, and tentative associations for the remaining objects. The redshift distribution of AzTEC sources is inferred from available spectroscopic and photometric redshifts. We find a median redshift of z = 2.7, somewhat higher than z = 2.0 for 850μm selected sources in the same field, and our lowest redshift identification lies at a spectroscopic redshift z = 1.1460. We measure the 850μm to 1.1mm colour of our sources and do not find evidence for `850μm dropouts', which can be explained by the low signal-to-noise ratio of the observations. We also combine these observed colours with spectroscopic redshifts to derive the range of dust temperatures T, and dust emissivity indices β for the sample, concluding that existing estimates T ~ 30K and β ~ 1.75 are consistent with these new data.

  15. Inactivation of genes TEC1 and EFG1 in Candida albicans influences extracellular matrix composition and biofilm morphology.

    PubMed

    Panariello, Beatriz Helena Dias; Klein, Marlise I; Pavarina, Ana Claudia; Duarte, Simone

    2017-01-01

    Background : Infections caused by Candida spp. have been associated with formation of a biofilm, i.e. a complex microstructure of cells adhering to a surface and embedded within an extracellular matrix (ECM). Methods : The ECMs of a wild-type (WT, SN425) and two Candida albicans mutant strains, Δ/Δ tec1 (CJN2330) and Δ/Δ efg1 (CJN2302), were evaluated. Colony-forming units (cfu), total biomass (mg), water-soluble polysaccharides (WSPs), alkali-soluble polysaccharides (ASPs), proteins (insoluble part of biofilms and matrix proteins), and extracellular DNA (eDNA) were quantified. Variable-pressure scanning electron microscopy and confocal scanning laser microscopy were performed. The biovolume (μm 3 /μm 2 ) and maximum thickness (μm) of the biofilms were quantified using COMSTAT2. Results : ASP content was highest in WT (mean ± SD: 74.5 ± 22.0 µg), followed by Δ/Δ tec1 (44.0 ± 24.1 µg) and Δ/Δ efg1 (14.7 ± 5.0 µg). The protein correlated with ASPs ( r  = 0.666) and with matrix proteins ( r  = 0.670) in the WT strain. The population in Δ/Δ efg1 correlated with the protein ( r  = 0.734) and its biofilms exhibited the lowest biomass and biovolume, and maximum thickness. In Δ/Δ tec1, ASP correlated with eDNA ( r  = 0.678). Conclusion : ASP production may be linked to C. albicans cell filamentous morphology.

  16. Spatial analyses on seismo-ionospheric precursors observed by GIM TEC and DEMETER during the 2008 M8.0 Wenchuan earthquake

    NASA Astrophysics Data System (ADS)

    Liu, Jann-Yenq; Chen, Yuh-Ing; Huang, Ching-Chi; Parrot, Michel; Pulinets, Sergey; Ouzounov, Dimitar

    2015-04-01

    This paper examines seismo-ionospheric precursors (SIPs) in the total electron content (TEC) of the global ionosphere map (GIM) and observations in the French satellite DEMETER (Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions) during the 12 May 2008 M8.0 Wenchuan earthquake. The temporal and spatial analyses on the GIM TEC are used to search SIPs of the Wenchuan earthquake. Meanwhile, both daytime and nighttime electron density (Ne), electron temperature (Te), ion density (Ni) and ion temperature (Ti) probed by DEMETER are investigated. A statistical analysis of the box-and-whisker method is utilized to see if the four DEMETER data sets 1-6 days before and after the earthquake are significantly different. The analysis is employed to investigate the epicenter and three reference areas along the same magnetic latitude discriminating the SIPs from global effects. Results show that the nighttime Ne and Ni (daytime Ti) over the epicenter significantly decrease (increase) 1-6 days before the earthquake. The intersections of the global distribution of the significant differences (or anomalous changes) in the nighttime Ne, the nighttime Ni, and the daytime Ti 1-6 days before and after the earthquake specifically appear over the epicenter. The spatial analyses confirm that SIPs of GIM TEC and DEMETER observations appearing 2-6 days before are related to the 2008 M8.0 Wenchuan earthquake.

  17. Local time, seasonal, and solar cycle dependency of longitudinal variations of TEC along the crest of EIA over India

    NASA Astrophysics Data System (ADS)

    Sunda, Surendra; Vyas, B. M.

    2013-10-01

    global wave number 4 structure in the Indian longitudinal region spanning from ~70 to 95°E forming the upward slope of the peak in the total electron content (TEC) are reported along the crest of equatorial ionization anomaly (EIA). The continuous and simultaneous measurements from five GPS stations of GPS Aided Geo Augmented Navigation (GAGAN) network are used in this study. The long-term database (2004-2012) is utilized for examining the local time, seasonal, and solar cycle dependency on the longitudinal variations of TEC. Our results confirm the existence of longitudinal variations of TEC in accordance with wave number 4 longitudinal structure including its strength. The results suggest that these variations, in general, start to develop at ~09 LT, achieve maximum strength at 12-15 LT, and decay thereafter, the decay rate depending on the season. They are more pronounced in equinoctial season followed by summer and winter. The longitudinal variations persist beyond midnight in equinox seasons, whereas in winter, they are conspicuously absent. Interestingly, they also exhibit significant solar cycle dependence in the solstices, whereas in the equinoxes, they are independent of solar activity. The comparison of crest-to-trough ratio (CTR) in the eastern (92°E) and western (72°E) extreme longitudes reveals higher CTR on the eastern side than over the western extreme, suggesting the role of nonmigrating tides in modulating the ExB vertical drift and the consequential EIA crest formation.

  18. TEC data ingestion into IRI and NeQuick over the antarctic region

    NASA Astrophysics Data System (ADS)

    Nava, Bruno; Pezzopane, Michael; Radicella, Sandro M.; Scotto, Carlo; Pietrella, Marco; Migoya Orue, Yenca; Alazo Cuartas, Katy; Kashcheyev, Anton

    2016-07-01

    In the present work a comparative analysis to evaluate the IRI and NeQuick 2 models capabilities in reproducing the ionospheric behaviour over the Antarctic Region has been performed. A technique to adapt the two models to GNSS-derived vertical Total Electron Content (TEC) has been therefore implemented to retrieve the 3-D ionosphere electron density at specific locations where ionosonde data were available. In particular, the electron density profiles used in this study have been provided in the framework of the AUSPICIO (AUtomatic Scaling of Polar Ionograms and Cooperative Ionospheric Observations) project applying the Adaptive Ionospheric Profiler (AIP) to ionograms recorded at eight selected mid, high-latitude and polar ionosondes. The relevant GNSS-derived vertical TEC values have been obtained from the Global Ionosphere Maps (GIM) produced by the Center for Orbit Determination in Europe (CODE). The effectiveness of the IRI and NeQuick 2 in reconstructing the ionosphere electron density at the given locations and epochs has been primarily assessed in terms of statistical comparison between experimental and model-retrieved peak parameters values (foF2 and hmF2). The analysis results indicate that in general the models are equivalent in their ability to reproduce the critical frequency of the F2 layer and they also tend to overestimate the height of the peak electron density, especially during high solar activity periods. Nevertheless this tendency is more noticeable in NeQuick 2 than in IRI. For completeness, the statistics indicating the models bottomside reconstruction capabilities, computed as height integrated electron density profile mismodeling, will also be discussed.

  19. Antibody responses induced by Leish-Tec®, an A2-based vaccine for visceral leishmaniasis, in a heterogeneous canine population.

    PubMed

    Testasicca, Miriam C de Souza; dos Santos, Mariana Silva; Machado, Leopoldo Marques; Serufo, Angela Vieira; Doro, Daniel; Avelar, Daniel; Tibúrcio, Ana Maria Leonardi; Abrantes, Christiane de Freitas; Machado-Coelho, George Luiz Lins; Grimaldi, Gabriel; Gazzinelli, Ricardo Tostes; Fernandes, Ana Paula

    2014-08-29

    Zoonotic visceral leishmaniasis (VL) is a widespread disease, and dogs are the main reservoirs for human parasite transmission. Hence, development of an effective vaccine that prevents disease and reduces the transmission of VL is required. As euthanasia of seropositive dogs is recommended in Brazil for VL epidemiological control, to include anti-VL canine vaccines as a mass control measure it is necessary to characterize the humoral responses induced by vaccination and if they interfere with the reactivity of vaccinated dogs in serological diagnostic tests. Leish-Tec(®) is an amastigote-specific A2 recombinant protein vaccine against canine visceral leishmaniasis (CVL) that is commercially available in Brazil. Here, we tested the immunogenicity of Leish-Tec(®) in a heterogeneous dog population by measuring A2-specific antibody responses. Healthy dogs (n=140) of various breeds were allocated to two groups: one group received Leish-Tec(®) (n=70), and the other group received a placebo (n=70). Anti-A2 or anti-Leishmania promastigote antigen (LPA) antibody levels were measured by ELISA in serum samples collected before and after vaccination. An immunochromatographic test (DPP) based on the recombinant K28 antigen was also used for serodiagnosis of CVL. Vaccinated animals, except one, remained seronegative for anti-LPA total IgG and anti-K28 antibodies. Conversely, seropositivity for anti-A2 total IgG antibodies was found in 98% of animals after vaccination. This value decreased to 81.13% at 6 months before rising again (98%), after the vaccination boost. Anti-A2 IgG2 and IgG1 titers were also increased in vaccinated animals relative to control animals. These data indicate that Leish-Tec(®) is immunogenic for dogs of different genetic backgrounds and that humoral responses induced by vaccination can be detected by A2-ELISA, but do not interfere with the LPA-ELISA and DPP diagnostic tests for CVL. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. 75 FR 11939 - Arkansas Lamp Manufacturing, Including On-Site Leased Workers From TEC, Van Buren, AR; Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-12

    ... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-71,714] Arkansas Lamp Manufacturing, Including On-Site Leased Workers From TEC, Van Buren, AR; Notice of Termination of Investigation... a petition filed on July 17, 2009, by a company official on behalf of workers of Arkansas Lamp...

  1. A new ionospheric storm scale based on TEC and foF2 statistics

    NASA Astrophysics Data System (ADS)

    Nishioka, Michi; Tsugawa, Takuya; Jin, Hidekatsu; Ishii, Mamoru

    2017-01-01

    In this paper, we propose the I-scale, a new ionospheric storm scale for general users in various regions in the world. With the I-scale, ionospheric storms can be classified at any season, local time, and location. Since the ionospheric condition largely depends on many factors such as solar irradiance, energy input from the magnetosphere, and lower atmospheric activity, it had been difficult to scale ionospheric storms, which are mainly caused by solar and geomagnetic activities. In this study, statistical analysis was carried out for total electron content (TEC) and F2 layer critical frequency (foF2) in Japan for 18 years from 1997 to 2014. Seasonal, local time, and latitudinal dependences of TEC and foF2 variabilities are excluded by normalizing each percentage variation using their statistical standard deviations. The I-scale is defined by setting thresholds to the normalized numbers to seven categories: I0, IP1, IP2, IP3, IN1, IN2, and IN3. I0 represents a quiet state, and IP1 (IN1), IP2 (IN2), and IP3 (IN3) represent moderate, strong, and severe positive (negative) storms, respectively. The proposed I-scale can be used for other locations, such as polar and equatorial regions. It is considered that the proposed I-scale can be a standardized scale to help the users to assess the impact of space weather on their systems.

  2. Detection of the mid-latitude Sporadic-E signal using GNSS/TEC and ALOS2 InSAR data

    NASA Astrophysics Data System (ADS)

    Suzuki, T.; Maeda, J.; Furuya, M.; Heki, K.

    2016-12-01

    Sporadic E (Es) is known to generate unusual propagation of VHF waves over long distances, which is caused by a layer of ionization that irregularly appears within the E region of the ionosphere. However, the generation mechanism of Es remains unclear, because the conventional ionosonde observation of Es has limited spatial resolution. Maeda et al. (2016) succeeded in capturing mid-latitude Es signal over Japan two-dimensionally as an image, using InSAR, and demonstrated the detailed spatial structure of Es. As InSAR is clearly useful for capturing Es, we aim to detect mid-latitude Es over Japan by InSAR, following Maeda et al. (2016). First, we chose the dates whose critical frequencies of Es (foEs) were more than 15MHz at ionosonde in Kokubunji, Wakkanai and Yamagawa in the morning and noon in 2016 from May to June; Es is known to be frequent in the local daytime of summer season. Secondly, we chose the ALOS-2/PALSAR-2 data sets whose observation area, dates and time matches the data above as closely as possible. Thirdly, we generated Global Navigation Satellite System - Total Electron Content (GNSS-TEC) map whose areas, dates and time become the same as the above and if Es appeared in GNSS-TEC map, we generate interferogram. We could detect interesting phase changes in the pair of February 17, 2016 (Master) and May 25, 2016 (Slave) along a track from Tottori to Okayama. The location of the phase shift is close to the Es on the GNSS-TEC image. Therefore, we can consider the phase shift as the edge of Es. This is the second successful detection of Es signals, using InSAR. Also, we are going to separate the Es signal from other non-dispersive signals, using split-band InSAR technique.

  3. Seismo-ionospheric anomalies in ionospheric TEC and plasma density before the 17 July 2006 M7.7 south of Java earthquake

    NASA Astrophysics Data System (ADS)

    Tao, Dan; Cao, Jinbin; Battiston, Roberto; Li, Liuyuan; Ma, Yuduan; Liu, Wenlong; Zhima, Zeren; Wang, Lanwei; Wray Dunlop, Malcolm

    2017-04-01

    In this paper, we report significant evidence for preseismic ionospheric anomalies in total electron content (TEC) of the global ionosphere map (GIM) and plasma density appearing on day 2 before the 17 July 2006 M7.7 south of Java earthquake. After distinguishing other anomalies related to the geomagnetic activities, we found a temporal precursor around the epicenter on day 2 before the earthquake (15 July 2006), which agrees well with the spatial variations in latitude-longitude-time (LLT) maps. Meanwhile, the sequences of latitude-time-TEC (LTT) plots reveal that the TECs on epicenter side anomalously decrease and lead to an anomalous asymmetric structure with respect to the magnetic equator in the daytime from day 2 before the earthquake. This anomalous asymmetric structure disappears after the earthquake. To further confirm these anomalies, we studied the plasma data from DEMETER satellite in the earthquake preparation zone (2046.4 km in radius) during the period from day 45 before to day 10 after the earthquake, and also found that the densities of both electron and total ion in the daytime significantly increase on day 2 before the earthquake. Very interestingly, O+ density increases significantly and H+ density decreases, while He+ remains relatively stable. These results indicate that there exists a distinct preseismic signal (preseismic ionospheric anomaly) over the epicenter.

  4. Receiver Operating Characteristic curves of the seismo-ionospheric precursors in GIM TEC associated with magnitude greater than 6.0 earthquakes in China during 1998-2013.

    NASA Astrophysics Data System (ADS)

    Huang, C. H.; Chen, Y. I.; Liu, J. Y. G.; Huang, Y. H.

    2014-12-01

    Statistical evidence of the Seismo-Ionospheric Precursors (SIPs) is reported by statistically investigating the relationship between the Total Electron Content (TEC) in Global Ionosphere Map (GIM) and 56 M≥6.0 earthquakes during 1998-2013 in China. A median-based method and a z test are employed to detect the overall earthquake signatures. It is found that a reduction of positive signatures and an enhancement of negative signatures appear simultaneously on 3-5 days prior to the earthquakes in China. Finally, receiver operating characteristic (ROC) curves are used to measure the power of TEC for predicting M≥6.0 earthquakes in China.

  5. Comparison between IRI-2012 and GPS-TEC observations over the western Black Sea

    NASA Astrophysics Data System (ADS)

    Inyurt, Samed; Yildirim, Omer; Mekik, Cetin

    2017-07-01

    The ionosphere is a dynamic layer which generally changes according to radiation emitted by the sun, the movement of the earth around the sun, and sunspot activity. Variations can generally be categorized as regular or irregular variations. Both types of variation have a huge effect on radio wave propagation. In this study, we have focused on the seasonal variation effect, which is one of the regular forms of variation in terms of the ionosphere. We examined the seasonal variation over the ZONG station in Turkey for the year 2014. Our analysis results and IRI-2012 present different ideas about ionospheric activity. According to our analysed results, the standard deviation reached a maximum value in April 2014. However, the maximum standard deviation obtained from IRI-2012 was seen in February 2014. Furthermore, it is clear that IRI-2012 underestimated the VTEC values when compared to our results for all the months analysed. The main source of difference between the two models is the IRI-2012 topside ionospheric representation. IRI-2012 VTEC has been produced as a result of the integration of an electron density profile within altitudinal limits of 60-2000 km. In other words, the main problem with regard to the IRI-2012 VTEC representation is not being situated in the plasmaspheric part of the ionosphere. Therefore we propose that the plasmaspheric part should be taken into account to calculate the correct TEC values in mid-latitude regions, and we note that IRI-2012 does not supply precise TEC values for use in ionospheric studies.

  6. Observation of TEC perturbation associated with medium-scale traveling ionospheric disturbance and possible seeding mechanism of atmospheric gravity wave at a Brazilian sector

    NASA Astrophysics Data System (ADS)

    Jonah, O. F.; Kherani, E. A.; De Paula, E. R.

    2016-03-01

    In the present study, we document daytime total electron content (TEC) disturbances associated with medium-scale traveling ionospheric disturbances (MSTIDs), on few chosen geomagnetically quiet days over Southern Hemisphere of Brazilian longitude sector. These disturbances are derived from TEC data obtained using Global Navigation Satellite System (GNSS) receiver networks. From the keograms and cross-correlation maps, the TEC disturbances are identified as the MSTIDs that are propagating equatorward-eastward, having most of their average wavelengths longer in latitude than in longitude direction. These are the important outcomes of the present study which suggest that the daytime MSTIDs over Southern Hemisphere are similar to their counterparts in the Northern Hemisphere. Another important outcome is that the occurrence characteristics of these MSTIDs and that of atmospheric gravity wave (AGW) activities in the thermosphere are found to be similar on day-to-day basis. This suggests a possible connection between them, confirming the widely accepted AGW forcing mechanism for the generation of these daytime MSTIDs. The source of this AGW is investigated using the Geostationary Operational Environmental Satellite system (GOES) and Constellation Observing System for Meteorology, Ionosphere, and Climate satellite data. Finally, we provided evidences that AGWs are generated by convection activities from the tropospheric region.

  7. Master Teachers in Residence: Bringing a Classroom Perspective to Course Reform for NSF's Oklahoma Teacher Education Collaborative (O-TEC).

    ERIC Educational Resources Information Center

    Ramsey, Sarah; Neathery, Faye; Fholer, Gwen; Weger, Elayne; Voth, Bonnie; Townsend, Joyce; Campbell, DeAnn; Boedecker, Martha

    Master teachers can be influential in course revision. The Oklahoma Teacher Education Collaborative (O-TEC) teacher reform effort is a consortium of nine higher education institutions working with the National Science Foundation's (NSF's) reform effort to produce teachers better equipped for teaching science and mathematics. The reform emphasizes…

  8. Extraction of the geomagnetic activity effect from TEC data: A comparison between the spectral whitening method and 28 day running median

    NASA Astrophysics Data System (ADS)

    Chen, Zhou; Wang, Jing-Song; Deng, Yue; Huang, Chun-Ming

    2017-03-01

    The spectral whitening method (SWM) has been previously proved to be very effective at identifying ionospheric disturbances on foF2 (the critical frequency of ionospheric F2 layer). To continuously investigate the strength of the new method, in this paper SWM has been used to extract the effect of geomagnetic activity on total electron content (TEC) and has been compared with the traditional 28 day running median centered (RMC) method. First, ionospheric variations during quiet and disturbed conditions are analyzed by both SWM and RMC. The results from RMC, compared with those from SWM, overestimate the disturbance occurrence by about 5-20% during the geomagnetic storms and up to 35% during the quiet time. The possible reason is that the results can be contaminated by the residuals of periodic components in the RMC identified disturbances. Meanwhile, the power spectral analysis of the disturbance field shows that the annual and diurnal variations are still significant in RMC results but very weak in SWM results, which indicates that SWM has some advantage to clean up the background variation. Finally, the analysis of the spatial correlation of the disturbance field with F10.7 and Ap illustrates that the effects of solar and geomagnetic activities from SWM are significantly reduced and enhanced, respectively. It suggests that the SWM is more effective in extracting the effect of geomagnetic activity from TEC than RMC. The relative deviation of TEC derived by SWM is more sensitive to geomagnetic activity than solar activity.

  9. Multicomponent LBSap vaccine displays immunological and parasitological profiles similar to those of Leish-Tec® and Leishmune® vaccines against visceral leishmaniasis.

    PubMed

    de Mendonça, Ludmila Zanandreis; Resende, Lucilene Aparecida; Lanna, Mariana Ferreira; Aguiar-Soares, Rodrigo Dian de Oliveira; Roatt, Bruno Mendes; Castro, Renata Alves de Oliveira E; Batista, Maurício Azevedo; Silveira-Lemos, Denise; Gomes, Juliana de Assis Silva; Fujiwara, Ricardo Toshio; Rezende, Simone Aparecida; Martins-Filho, Olindo Assis; Corrêa-Oliveira, Rodrigo; Dutra, Walderez Ornelas; Reis, Alexandre Barbosa; Giunchetti, Rodolfo Cordeiro

    2016-08-30

    In past years, many researchers have sought canine visceral leishmaniasis (CVL) prevention through the characterization of Leishmania antigens as vaccine candidates. Despite these efforts, there is still no efficient vaccine for CVL control. In the present study, we performed a pre-clinical vaccine trial using BALB/c mice to compare the effects of the multicomponent LBSap vaccine with those of Leish-Tec® and Leishmune®. Blood was collected to determine the frequency of peripheral blood cells and to evaluate hematologic and immunophenotypic parameters. Liver and spleen samples were collected for parasitological quantification, and spleen samples were used to access the cytokine profile. When measuring total IgG and IgG1 anti-Leishmania levels after the third vaccination and L. infantum challenge, it was evident that all vaccines were able to induce humoral immune response. Regarding the innate immune response, increased levels of NK CD3(-)CD49(+) cells were the hallmark of all vaccinated groups, whereas only the Leish-Tec® group displayed a high frequency of CD14(+) monocytes after L. infantum challenge. Moreover, CD3(+)CD4(+) T cells were the main circulating lymphocytes induced after L. infantum challenge with all evaluated vaccines. Importantly, after L. infantum challenge, splenocytes from the Leishmune® vaccine produced high levels of IL-2, whereas a prominent type 1 immune response was the hallmark of the LBSap vaccine, which presented high levels of IL-2, IL-6, TNF-α, and IFN-γ. The efficacy analysis using real-time polymerase chain reaction demonstrated a reduction in the parasitism in the spleen (Leishmune®: 64 %; LBSap: 42 %; and Leish-Tec®: 36 %) and liver (Leishmune®: 71 %; LBSap: 62 %; and Leish-Tec®: 48 %). The dataset led to the conclusion that the LBSap vaccination was able to induce immune and efficacy profiles comparable with those of commercial vaccines, thus demonstrating its potential as a promising vaccine candidate for visceral

  10. Activation Loop Dynamics Determine the Different Catalytic Efficiencies of B Cell- and T Cell-Specific Tec Kinases

    PubMed Central

    Joseph, Raji E.; Kleino, Iivari; Wales, Thomas E.; Xie, Qian; Fulton, D. Bruce; Engen, John R.; Berg, Leslie J.; Andreotti, Amy H.

    2014-01-01

    Itk and Btk are nonreceptor tyrosine kinases of the Tec family that signal downstream of the T cell receptor (TCR) and B cell receptor (BCR), respectively. Despite their high sequence similarity and related signaling roles, Btk is a substantially more active kinase than Itk. We showed that substitution of six of the 619 amino acid residues of Itk with those of Btk was sufficient to completely switch the activities of Itk and Btk. The substitutions responsible for the swap in activity are all localized to the activation segment of the kinase domain. Nuclear magnetic resonance and hydrogen-deuterium exchange mass spectrometry analyses revealed that Itk and Btk had distinct protein dynamics in this region, which could explain the observed differences in catalytic efficiency between these kinases. Introducing Itk with enhanced activity into T cells led to enhanced and prolonged TCR signaling compared to that in cells with wild-type Itk. These findings imply that evolutionary pressures have led to Tec kinases having distinct enzymatic properties depending on the cellular context. We suggest that the weaker catalytic activities observed for T cell–specific kinases is one mechanism to regulate cellular activation and prevent aberrant immune responses. PMID:23982207

  11. Effect of Thermoelectric Cooling (TEC) module and the water flow heatsink on Photovoltaic (PV) panel performance

    NASA Astrophysics Data System (ADS)

    Amelia, A. R.; Jusoh, MA; Shamira Idris, Ida

    2017-11-01

    Photovoltaic (PV) panel suffers in low conversion efficiency of the output performance affected by the elevated operating temperature of the PV panel. It is important to keep the PV panel to operate at low temperature. To address this issue, this paper proposes the cooling system using thermoelectric cooling (TEC) and water block heatsink for enhancing the PV panel output performance. These both types cooling system were designed located on the back side of the PV panel to cool down the operating temperature of the PV panel. To evaluate the function for the existing cooling systems, the experiment was subsequently performed for PV panel without and with different design of the cooling system in outdoor weather conditions. By comparing the experimental results, it is concluded that by the hybrid cooling system which combining TEC module and the water block heatsink could improve the output performance of the PV panel. By the reduction temperature of the PV panel by 16.04 %, the average output power of the PV panel has been boosted up from 8.59 W to 9.03 W. In short, the output power of the PV panel was enhanced by the reduction of the operating temperature of the PV panel.

  12. Variations of TEC near the Indian Equatorial Ionospheric anomaly (EIA) stations by GPS measurements during descending phase of solar activity (2005 -2009)

    NASA Astrophysics Data System (ADS)

    Kumar, Sanjay; Singh, Abhay Kumar

    The dual frequency Global Positioning System (GPS) data recorded at Varanasi (geographic latitude 250, 16 N longitude 820, 59 E) and Kanpur (geographic latitude 260, 30 N longitude 800, 12 E) stations, near the equatorial ionosphere anomaly (EIA) in India, have been analyzed to retrieve total electron content (TEC). The daily peak value of vertical total electron content (VTEC) has been utilized to study the variability of EIA. Present paper studied monthly, seasonal and annual variations as well as solar and geomagnetic effects on EIA. It has been found that EIA yield their maximum values during the equinox months and minimum during summer and winter. The correlations of EIA with solar as well as geomagnetic indices have been also discussed. Key words: Total electron contents (TECs), EIA, GPS.

  13. Growth of L-band scintillation at anomaly crest station in association with strong TEC gradient: A study covering wide solar activity period

    NASA Astrophysics Data System (ADS)

    Pathak, K.; Devi, M.; Barbara, A. K.; Zahan, Y.

    2018-01-01

    The paper aims at to study the sources associated with growth of L band scintillation over Guwahati, an Appleton anomaly region. Starting with the analysis of diurnal and seasonal characteristic features of scintillation from a minimum sunspot number (Rz) of 10 to a maximum of 140, the paper shows that scintillations are more likely to develop during high solar activity period. It also highlights the explosive increase in occurrence of scintillation from post sunset to pre midnight hours in vernal equinoctial months when the background TEC is 50% more than on a normal day, accompanied by enhanced TEC decay rate. The role of equatorial anomaly effects through EXB drift processes are brought into discussion as possible sources on the growth of small scale irregularities leading to such scintillations.

  14. Growth of L-band scintillation at anomaly crest station in association with strong TEC gradient: A study covering wide solar activity period

    NASA Astrophysics Data System (ADS)

    Pathak, K.; Devi, M.; Barbara, A. K.; Zahan, Y.

    2018-07-01

    The paper aims at to study the sources associated with growth of L band scintillation over Guwahati, an Appleton anomaly region. Starting with the analysis of diurnal and seasonal characteristic features of scintillation from a minimum sunspot number (Rz) of 10 to a maximum of 140, the paper shows that scintillations are more likely to develop during high solar activity period. It also highlights the explosive increase in occurrence of scintillation from post sunset to pre midnight hours in vernal equinoctial months when the background TEC is 50% more than on a normal day, accompanied by enhanced TEC decay rate. The role of equatorial anomaly effects through EXB drift processes are brought into discussion as possible sources on the growth of small scale irregularities leading to such scintillations.

  15. Comparison of (1->3)-β-D-glucan, mannan/anti-mannan antibodies, and Cand-Tec Candida antigen as serum biomarkers for candidemia.

    PubMed

    Held, Jürgen; Kohlberger, Isabelle; Rappold, Elfriede; Busse Grawitz, Andrea; Häcker, Georg

    2013-04-01

    We conducted a case-control study using the Fungitell assay, the novel Platelia Candida Antigen (Ag) Plus and Candida Antibody (Ab) Plus assays, and the Cand-Tec latex agglutination test to evaluate the usefulness of (1→3)-β-D-glucan (BDG), mannan antigen with/without anti-mannan antibody, and Cand-Tec Candida antigen measurement for the diagnosis of candidemia. A total of 56 patients fulfilled the inclusion criteria and were enrolled. One hundred patients with bacteremia and 100 patients with sterile blood cultures served as negative controls. In the candidemia group, median (1→3)-β-D-glucan, mannan antigen, and anti-mannan antibody levels were 427 pg/ml, 190 pg/ml, and 18.6 antibody units (AU)/ml, respectively. All three parameters were significantly elevated in patients with candidemia. The sensitivity and specificity were, respectively, 87.5% and 85.5% for (1→3)-β-D-glucan, 58.9% and 97.5% for mannan antigen, 62.5% and 65.0% for anti-mannan antibody, 89.3% and 63.0% for mannan antigen plus anti-mannan antibody, 89.3% and 85.0% for BDG plus mannan antigen, and 13.0% and 93.9% for Cand-Tec Candida antigen. The low mannan antigen sensitivity was in part caused by Candida parapsilosis and Candida guilliermondii fungemias, which were not detected by the Platelia Candida Ag Plus assay. When the cutoff was lowered from 125 pg/ml to 50 pg/ml, mannan antigen sensitivity increased to 69.6% without severely affecting the specificity (93.5%). Contrary to recently published data, superficial candidiasis was not associated with elevated mannan antigen levels, not even after the cutoff was lowered. Combining procalcitonin (PCT) with (1→3)-β-D-glucan to increase specificity provided a limited advantage because the benefit of the combination did not outweigh the loss of sensitivity. Our results demonstrate that the Cand-Tec Candida antigen and the mannan antigen plus anti-mannan antibody measurements have unacceptably low sensitivity or specificity. Of the four

  16. Removal of Inorganic, Microbial, and Particulate Contaminants from a Fresh Surface Water: Village Marine Tec. Expeditionary Unit Water Purifier, Generation 1

    EPA Science Inventory

    The Village Marine Tec. Generation 1 Expeditionary Unit Water Purifier (EUWP) is a mobile skid-mounted system employing ultrafiltration (UF) and reverse osmosis (RO) to produce drinking water from a variety of different water quality sources. The UF components were evaluated to t...

  17. Ionospheric TEC from the Turkish Permanent GNSS Network (TPGN) and comparison with ARMA and IRI models

    NASA Astrophysics Data System (ADS)

    Ansari, Kutubuddin; Panda, Sampad Kumar; Althuwaynee, Omar F.; Corumluoglu, Ozsen

    2017-09-01

    The present study investigates the ionospheric Total Electron Content (TEC) variations in the lower mid-latitude Turkish region from the Turkish Permanent GNSS Network (TPGN) and International GNSS Services (IGS) observations during the year 2016. The corresponding vertical TEC (VTEC) predicted by Auto Regressive Moving Average (ARMA) and International Reference Ionosphere 2016 (IRI-2016) models are evaluated to realize their effectiveness over the region. The spatial, diurnal and seasonal behavior of VTEC and the relative VTEC variations are modeled with Ordinary Least Square Estimator (OLSE). The spatial behavior of modeled result during March equinox and June solstice indicates an inverse relationship of VTEC with the longitude across the region. On the other hand, the VTEC variation during September equinox and December solstice including March equinox and June solstice are decreasing with increase in latitude. The GNSS observed and modeled diurnal variation of the VTEC show that the VTEC slowly increases with dawn, attains a broader duration of peak around 09.00 to 12.00 UT, and thereafter decreases gradually reaching minimum around 21.00 UT. The seasonal variation of VTEC shows an annual mode, maxima in equinox and minima in solstice. The average value of VTEC during the June solstice is with slightly higher value than the March equinox though variations during the latter season is more. Moreover, the study shows minimum average value during December solstice compared to June solstice at all stations. The comparative analysis demonstrates the prediction errors by OLSE, ARMA and IRI remaining between 0.23 to 1.17%, 2.40 to 4.03% and 24.82 to 25.79% respectively. Also, the observed VTEC seasonal variation has good agreement with OLSE and ARMA models whereas IRI-VTEC often underestimated the observed value at each location. Hence, the deviations of IRI estimated VTEC compared to ARMA and OLSE models claim further improvements in IRI model over the Turkish region

  18. Field randomized trial to evaluate the efficacy of the Leish-Tec® vaccine against canine visceral leishmaniasis in an endemic area of Brazil.

    PubMed

    Regina-Silva, Shara; Feres, Ana Maria Leonardi Tibúrcio; França-Silva, João Carlos; Dias, Edelberto Santos; Michalsky, Érika Monteiro; de Andrade, Hélida Monteiro; Coelho, Eduardo Antonio Ferraz; Ribeiro, Gustavo Meirelles; Fernandes, Ana Paula; Machado-Coelho, George Luiz Lins

    2016-04-27

    A canine vaccine remains a promising approach for effective control of visceral leishmaniasis (VL), given its complex epidemiology in areas where zoonotic VL is prevalent. Leish-Tec(®) is a recombinant vaccine, based on the Leishmania A2 antigen, against canine VL (CVL). It is, since 2014, the single commercial vaccine licensed in Brazil. Here, Leish-Tec(®) efficacy was estimated through a randomized field trial (RFT), in a highly VL endemic area. The RFT was conducted from 2008 to 2010 in an endemic area of southeastern Brazil, presenting a CVL seroprevalence of 41.9%. Eight hundred forty-seven seronegative dogs were randomly selected to receive Leish-Tec(®) (n=429) or placebo (n=418). Animals were followed up by clinical, serological, and parasitological exams for 18 months. The CVL incidence in both groups was compared through proportion analysis. A significant reduction in the number of cases of CVL was observed in the vaccine group, as compared with the placebo group, whether efficacy was estimated according to parasitological results (71.4%; 95% CI: 34.9-87.3%; p=0.001; risk ratio=0.287), by adding results of xenodiagnosis and parasitological exams (58.1%; 95% CI: 26.0-76.3%; p=0.002; risk ratio=0.419). Among the animals that converted to a positive anti-A2 serology, efficacy reached 80.8% (95% CI: 37.6-94.1%, p=0.001; risk ratio=0.192). Xenodiagnosis has detected a reduction of 46.6% (p=0.05) in transmission to sand flies from vaccinated animals presenting anti-A2 positive serology. The Leish-Tec(®) vaccine proved significantly effective for prophylaxis of CVL, after natural challenge assured by transmission of Leishmania parasites, in a highly endemic area. Noteworthy, this report has unveiled the complexity of performing a RFT for anti-CVL vaccines in Brazil, which may be helpful for designing of future studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. First results from the ionospheric tomography experiment using beacon TEC data obtained by means of a network along a longitude of 136°E over Japan

    NASA Astrophysics Data System (ADS)

    Thampi, Smitha V.; Yamamoto, Mamoru

    2010-03-01

    A chain of newly designed GNU (GNU is not UNIX) Radio Beacon Receivers (GRBR) has recently been established over Japan, primarily for tomographic imaging of the ionosphere over this region. Receivers installed at Shionomisaki (33.45°N, 135.8°E), Shigaraki (34.8°N, 136.1°E), and Fukui (36°N, 136°E) continuously track low earth orbiting satellites (LEOS), mainly OSCAR, Cosmos, and FORMOSAT-3/COSMIC, to obtain simultaneous total electron content (TEC) data from these three locations, which are then used for the tomographic reconstruction of ionospheric electron densities. This is the first GRBR network established for TEC observations, and the first beacon-based tomographic imaging in Japanese longitudes. The first tomographic images revealed the temporal evolution with all of the major features in the ionospheric electron density distribution over Japan. A comparison of the tomographically reconstructed electron densities with the ƒ o F 2 data from Kokubunji (35°N, 139°E) revealed that there was good agreement between the datasets. These first results show the potential of GRBR and its network for making continuous, unattended ionospheric TEC measurements and for tomographic imaging of the ionosphere.

  20. (Sub)millimetre interferometric imaging of a sample of COSMOS/AzTEC submillimetre galaxies. IV. Physical properties derived from spectral energy distributions

    NASA Astrophysics Data System (ADS)

    Miettinen, O.; Delvecchio, I.; Smolčić, V.; Novak, M.; Aravena, M.; Karim, A.; Murphy, E. J.; Schinnerer, E.; Capak, P.; Ilbert, O.; Intema, H. T.; Laigle, C.; McCracken, H. J.

    2017-01-01

    Context. Submillimetre galaxies (SMGs) in the early Universe are potential antecedents of the most massive galaxies we see in the present-day Universe. An important step towards quantifying this galactic evolutionary connection is to investigate the fundamental physical properties of SMGs, such as their stellar mass content (M⋆) and star formation rate (SFR). Aims: We attempt to characterise the physical nature of a 1.1 mm selected, flux-limited, and interferometrically followed up sample of SMGs in the COSMOS field. Methods: We used the latest release of the MAGPHYS code to fit the multiwavelength (UV to radio) spectral energy distributions (SEDs) of 16 of the target SMGs, which lie at redshifts z ≃ 1.6-5.3. We also constructed the pure radio SEDs of our SMGs using three different radio bands (325 MHz, 1.4 GHz, and 3 GHz). Moreover, since two SMGs in our sample, AzTEC 1 and AzTEC 3, benefit from previous 12C16O line observations, we studied their properties in more detail. Results: The median and 16th-84th percentile ranges of M⋆, infrared (8-1000 μm) luminosity (LIR), SFR, dust temperature (Tdust), and dust mass (Mdust) were derived to be log (M⋆/M⊙) = 10.96+ 0.34-0.19, log (LIR/L⊙) = 12.93+ 0.09-0.19, SFR = 856+ 191-310M⊙ yr-1, Tdust = 40.6+ 7.5-8.1 K, and log (Mdust/M⊙) = 9.17+ 0.03-0.33, respectively. We found that 63% of our target SMGs lie above the galaxy main sequence by more than a factor of 3 and, hence, are starbursts. The 3 GHz radio sizes we have previously measured for the target SMGs were compared with the present M⋆ estimates, and we found that the z> 3 SMGs are fairly consistent with the mass-size relationship of z 2 compact, quiescent galaxies (cQGs). The median radio spectral index is found to be α = -0.77+ 0.28-0.42. The median IR-radio correlation parameter is found to be q = 2.27+ 0.27-0.13, which is lower than was measured locally (median q = 2.64). The gas-to-dust mass ratio for AzTEC 1 is derived to be δgdr = 90+ 23

  1. Ionospheric perturbations due to earthquakes as determined from VLF and GPS-TEC data analysis at Agra, India

    NASA Astrophysics Data System (ADS)

    Singh, Dhananjali; Singh, Birbal; Pundhir, Devbrat

    2018-04-01

    Employing SoftPAL receiver, amplitude variations of VLF transmitter signals NWC (19.8 kHz) and NPM (21.4 kHz) are analyzed at Agra station in India (Geograph. lat. 27.2°N, long. 78°E) ±15 days from five major earthquakes of magnitude M = 6.9-8.5 occurred in Indian subcontinent during the years 2011-2013. We apply nighttime fluctuation (NF) method and show that in almost all cases the trend decreases and dispersion and NF increase on the same days corresponding to each earthquake about 11-15 days prior to the main shock. Assuming that the ionospheric perturbations are caused by atmospheric gravity waves (AGW), we also calculate AGW modulation index for each case and find its values increased on the days amplitude fluctuations take place. Its value is decreased in one case only where the perturbations may be attributed to penetration of seismogenic electric field. In order to support the above results we also present GPS-TEC data analyzed by us corresponding to three of the above earthquakes. We study the TEC anomalies (unusual enhancements) and find that in one case the precursory period is almost the same as that found in NF method.

  2. Ionospheric turbulence from TEC variations and VLF/LF transmitter signal observations before and during the destructive seismic activity of August and October 2016 in Central Italy

    NASA Astrophysics Data System (ADS)

    Contadakis, Michael E.; Arabelos, Demetrios N.; Vergos, George; Spatala, Spyrous; Skeberis, Christos; Xenos, Tomas D.; Biagi, Pierfrancesco; Scordilis, Emmanuel M.

    2017-04-01

    In this paper we investigate the ionospheric turbulence from TEC variations and VLF/LF transmitter signal observations before and during the disastrous seismic activity of August and October 2016 in Central Italy . The Total Electron Content (TEC) data of 8 Global Positioning System (GPS) stations of the EUREF network, which are being provided by IONOLAB (Turkey), were analysed using Discrete Fourier Analysis in order to investigate the TEC variations (Contadakis et al. 2009, Contadakis et al. 2012, Contadakis et al. 2015). The data acquired for VLF/LF signal observations are from the receiver of Thessaloniki(40.59N, 22,78E), Greece (Skeberis et al. 2015) which monitor the VLF/LF transmitters of the International Network for Frontier Research on Earthquake Precursors (INFREP). A method of normalization according to the distance between the receiver and the transmitter is applied on the above data and then they are processed by the Hilbert Huang Transform (HHT) to produce the corresponding spectra for visual analysis. The results of this investigation indicate that the High- Frequency limit fo, of the ionospheric turbulence content, increases as the site and the moment of the earthquake occurrence is approaching, pointing to the earthquake locus. In accordence ,the analyzed data from the receiver of INFREP network in Thessaloniki, Greece show that the signals from the two VLF European transmitters, Tavolara ( Italy) and Le Blanc (France), for wich the transmission path crosses the epicentral zones, indicate enhanced high frequency variations, the last ten days before the moment of the earthquake occurrence. We conclude that the LAIC mechanism through acoustic or gravity wave could explain this phenomenology. Reference Contadakis, M.E., Arabelos, D.N., Asteriadis, G., Spatalas, S.D., Pikridas, C. TEC variations over the Mediterranean during the seismic activity period of the last quarter of 2005 in the area of Greece, Nat. Hazards and Earth Syst. Sci., 8, 1267

  3. Digital beacon receiver for ionospheric TEC measurement developed with GNU Radio

    NASA Astrophysics Data System (ADS)

    Yamamoto, M.

    2008-11-01

    A simple digital receiver named GNU Radio Beacon Receiver (GRBR) was developed for the satellite-ground beacon experiment to measure the ionospheric total electron content (TEC). The open-source software toolkit for the software defined radio, GNU Radio, is utilized to realize the basic function of the receiver and perform fast signal processing. The software is written in Python for a LINUX PC. The open-source hardware called Universal Software Radio Peripheral (USRP), which best matches the GNU Radio, is used as a front-end to acquire the satellite beacon signals of 150 and 400 MHz. The first experiment was successful as results from GRBR showed very good agreement to those from the co-located analog beacon receiver. Detailed design information and software codes are open at the URL http://www.rish.kyoto-u.ac.jp/digitalbeacon/.

  4. Comparison of (1→3)-β-d-Glucan, Mannan/Anti-Mannan Antibodies, and Cand-Tec Candida Antigen as Serum Biomarkers for Candidemia

    PubMed Central

    Kohlberger, Isabelle; Rappold, Elfriede; Busse Grawitz, Andrea; Häcker, Georg

    2013-01-01

    We conducted a case-control study using the Fungitell assay, the novel Platelia Candida Antigen (Ag) Plus and Candida Antibody (Ab) Plus assays, and the Cand-Tec latex agglutination test to evaluate the usefulness of (1→3)-β-d-glucan (BDG), mannan antigen with/without anti-mannan antibody, and Cand-Tec Candida antigen measurement for the diagnosis of candidemia. A total of 56 patients fulfilled the inclusion criteria and were enrolled. One hundred patients with bacteremia and 100 patients with sterile blood cultures served as negative controls. In the candidemia group, median (1→3)-β-d-glucan, mannan antigen, and anti-mannan antibody levels were 427 pg/ml, 190 pg/ml, and 18.6 antibody units (AU)/ml, respectively. All three parameters were significantly elevated in patients with candidemia. The sensitivity and specificity were, respectively, 87.5% and 85.5% for (1→3)-β-d-glucan, 58.9% and 97.5% for mannan antigen, 62.5% and 65.0% for anti-mannan antibody, 89.3% and 63.0% for mannan antigen plus anti-mannan antibody, 89.3% and 85.0% for BDG plus mannan antigen, and 13.0% and 93.9% for Cand-Tec Candida antigen. The low mannan antigen sensitivity was in part caused by Candida parapsilosis and Candida guilliermondii fungemias, which were not detected by the Platelia Candida Ag Plus assay. When the cutoff was lowered from 125 pg/ml to 50 pg/ml, mannan antigen sensitivity increased to 69.6% without severely affecting the specificity (93.5%). Contrary to recently published data, superficial candidiasis was not associated with elevated mannan antigen levels, not even after the cutoff was lowered. Combining procalcitonin (PCT) with (1→3)-β-d-glucan to increase specificity provided a limited advantage because the benefit of the combination did not outweigh the loss of sensitivity. Our results demonstrate that the Cand-Tec Candida antigen and the mannan antigen plus anti-mannan antibody measurements have unacceptably low sensitivity or specificity. Of the four

  5. Recent Progress in Understanding Natural-Hazards-Generated TEC Perturbations: Measurements and Modeling Results

    NASA Astrophysics Data System (ADS)

    Komjathy, A.; Yang, Y. M.; Meng, X.; Verkhoglyadova, O. P.; Mannucci, A. J.; Langley, R. B.

    2015-12-01

    Natural hazards, including earthquakes, volcanic eruptions, and tsunamis, have been significant threats to humans throughout recorded history. The Global Positioning System satellites have become primary sensors to measure signatures associated with such natural hazards. These signatures typically include GPS-derived seismic deformation measurements, co-seismic vertical displacements, and real-time GPS-derived ocean buoy positioning estimates. Another way to use GPS observables is to compute the ionospheric total electron content (TEC) to measure and monitor post-seismic ionospheric disturbances caused by earthquakes, volcanic eruptions, and tsunamis. Research at the University of New Brunswick (UNB) laid the foundations to model the three-dimensional ionosphere at NASA's Jet Propulsion Laboratory by ingesting ground- and space-based GPS measurements into the state-of-the-art Global Assimilative Ionosphere Modeling (GAIM) software. As an outcome of the UNB and NASA research, new and innovative GPS applications have been invented including the use of ionospheric measurements to detect tiny fluctuations in the GPS signals between the spacecraft and GPS receivers caused by natural hazards occurring on or near the Earth's surface.We will show examples for early detection of natural hazards generated ionospheric signatures using ground-based and space-borne GPS receivers. We will also discuss recent results from the U.S. Real-time Earthquake Analysis for Disaster Mitigation Network (READI) exercises utilizing our algorithms. By studying the propagation properties of ionospheric perturbations generated by natural hazards along with applying sophisticated first-principles physics-based modeling, we are on track to develop new technologies that can potentially save human lives and minimize property damage. It is also expected that ionospheric monitoring of TEC perturbations might become an integral part of existing natural hazards warning systems.

  6. An AzTEC 1.1-mm survey for ULIRGs in the field of the Galaxy Cluster MS0451.6-0305

    NASA Astrophysics Data System (ADS)

    Wardlow, J. L.; Smail, Ian; Wilson, G. W.; Yun, M. S.; Coppin, K. E. K.; Cybulski, R.; Geach, J. E.; Ivison, R. J.; Aretxaga, I.; Austermann, J. E.; Edge, A. C.; Fazio, G. G.; Huang, J.; Hughes, D. H.; Kodama, T.; Kang, Y.; Kim, S.; Mauskopf, P. D.; Perera, T. A.; Scott, K. S.

    2010-02-01

    We have undertaken a deep (σ ~ 1.1 mJy) 1.1-mm survey of the z = 0.54 cluster MS0451.6-0305 using the AzTEC camera on the James Clerk Maxwell Telescope. We detect 36 sources with signal-to-noise ratio (S/N) >= 3.5 in the central 0.10 deg2 and present the AzTEC map, catalogue and number counts. We identify counterparts to 18 sources (50 per cent) using radio, mid-infrared, Spitzer InfraRed Array Camera (IRAC) and Submillimetre Array data. Optical, near- and mid-infrared spectral energy distributions are compiled for the 14 of these galaxies with detectable counterparts, which are expected to contain all likely cluster members. We then use photometric redshifts and colour selection to separate background galaxies from potential cluster members and test the reliability of this technique using archival observations of submillimetre galaxies. We find two potential MS0451-03 members, which, if they are both cluster galaxies, have a total star formation rate (SFR) of ~100Msolaryr-1 - a significant fraction of the combined SFR of all the other galaxies in MS0451-03. We also examine the stacked rest-frame mid-infrared, millimetre and radio emission of cluster members below our AzTEC detection limit, and find that the SFRs of mid-IR-selected galaxies in the cluster and redshift-matched field populations are comparable. In contrast, the average SFR of the morphologically classified late-type cluster population is nearly three times less than the corresponding redshift-matched field galaxies. This suggests that these galaxies may be in the process of being transformed on the red sequence by the cluster environment. Our survey demonstrates that although the environment of MS0451-03 appears to suppress star formation in late-type galaxies, it can support active, dust-obscured mid-IR galaxies and potentially millimetre-detected LIRGs.

  7. AzTEC half square degree survey of the SHADES fields - I. Maps, catalogues and source counts

    NASA Astrophysics Data System (ADS)

    Austermann, J. E.; Dunlop, J. S.; Perera, T. A.; Scott, K. S.; Wilson, G. W.; Aretxaga, I.; Hughes, D. H.; Almaini, O.; Chapin, E. L.; Chapman, S. C.; Cirasuolo, M.; Clements, D. L.; Coppin, K. E. K.; Dunne, L.; Dye, S.; Eales, S. A.; Egami, E.; Farrah, D.; Ferrusca, D.; Flynn, S.; Haig, D.; Halpern, M.; Ibar, E.; Ivison, R. J.; van Kampen, E.; Kang, Y.; Kim, S.; Lacey, C.; Lowenthal, J. D.; Mauskopf, P. D.; McLure, R. J.; Mortier, A. M. J.; Negrello, M.; Oliver, S.; Peacock, J. A.; Pope, A.; Rawlings, S.; Rieke, G.; Roseboom, I.; Rowan-Robinson, M.; Scott, D.; Serjeant, S.; Smail, I.; Swinbank, A. M.; Stevens, J. A.; Velazquez, M.; Wagg, J.; Yun, M. S.

    2010-01-01

    We present the first results from the largest deep extragalactic mm-wavelength survey undertaken to date. These results are derived from maps covering over 0.7deg2, made at λ = 1.1mm, using the AzTEC continuum camera mounted on the James Clerk Maxwell Telescope. The maps were made in the two fields originally targeted at λ = 850μm with the Submillimetre Common-User Bolometer Array (SCUBA) in the SCUBA Half-Degree Extragalactic Survey (SHADES) project, namely the Lockman Hole East (mapped to a depth of 0.9-1.3 mJy rms) and the Subaru/XMM-Newton Deep Field (mapped to a depth of 1.0-1.7 mJy rms). The wealth of existing and forthcoming deep multifrequency data in these two fields will allow the bright mm source population revealed by these new wide-area 1.1mm images to be explored in detail in subsequent papers. Here, we present the maps themselves, a catalogue of 114 high-significance submillimetre galaxy detections, and a thorough statistical analysis leading to the most robust determination to date of the 1.1mm source number counts. These new maps, covering an area nearly three times greater than the SCUBA SHADES maps, currently provide the largest sample of cosmological volumes of the high-redshift Universe in the mm or sub-mm. Through careful comparison, we find that both the Cosmic Evolution Survey (COSMOS) and the Great Observatories Origins Deep Survey (GOODS) North fields, also imaged with AzTEC, contain an excess of mm sources over the new 1.1mm source-count baseline established here. In particular, our new AzTEC/SHADES results indicate that very luminous high-redshift dust enshrouded starbursts (S1.1mm > 3mJy) are 25-50 per cent less common than would have been inferred from these smaller surveys, thus highlighting the potential roles of cosmic variance and clustering in such measurements. We compare number count predictions from recent models of the evolving mm/sub-mm source population to these sub-mm bright galaxy surveys, which provide important

  8. Deep 1.1 mm-wavelength imaging of the GOODS-S field by AzTEC/ASTE - II. Redshift distribution and nature of the submillimetre galaxy population

    NASA Astrophysics Data System (ADS)

    Yun, Min S.; Scott, K. S.; Guo, Yicheng; Aretxaga, I.; Giavalisco, M.; Austermann, J. E.; Capak, P.; Chen, Yuxi; Ezawa, H.; Hatsukade, B.; Hughes, D. H.; Iono, D.; Johnson, S.; Kawabe, R.; Kohno, K.; Lowenthal, J.; Miller, N.; Morrison, G.; Oshima, T.; Perera, T. A.; Salvato, M.; Silverman, J.; Tamura, Y.; Williams, C. C.; Wilson, G. W.

    2012-02-01

    We report the results of the counterpart identification and a detailed analysis of the physical properties of the 48 sources discovered in our deep 1.1-mm wavelength imaging survey of the Great Observatories Origins Deep Survey-South (GOODS-S) field using the AzTEC instrument on the Atacama Submillimeter Telescope Experiment. One or more robust or tentative counterpart candidate is found for 27 and 14 AzTEC sources, respectively, by employing deep radio continuum, Spitzer/Multiband Imaging Photometer for Spitzer and Infrared Array Camera, and Large APEX Bolometer Camera 870 μm data. Five of the sources (10 per cent) have two robust counterparts each, supporting the idea that these galaxies are strongly clustered and/or heavily confused. Photometric redshifts and star formation rates (SFRs) are derived by analysing ultraviolet(UV)-to-optical and infrared(IR)-to-radio spectral energy distributions (SEDs). The median redshift of zmed˜ 2.6 is similar to other earlier estimates, but we show that 80 per cent of the AzTEC-GOODS sources are at z≥ 2, with a significant high-redshift tail (20 per cent at z≥ 3.3). Rest-frame UV and optical properties of AzTEC sources are extremely diverse, spanning 10 mag in the i- and K-band photometry (a factor of 104 in flux density) with median values of i= 25.3 and K= 22.6 and a broad range of red colour (i-K= 0-6) with an average value of i-K≈ 3. These AzTEC sources are some of the most luminous galaxies in the rest-frame optical bands at z≥ 2, with inferred stellar masses M*= (1-30) × 1010 M⊙ and UV-derived SFRs of SFRUV≳ 101-3 M⊙ yr-1. The IR-derived SFR, 200-2000 M⊙ yr-1, is independent of z or M*. The resulting specific star formation rates, SSFR ≈ 1-100 Gyr-1, are 10-100 times higher than similar mass galaxies at z= 0, and they extend the previously observed rapid rise in the SSFR with redshift to z= 2-5. These galaxies have a SFR high enough to have built up their entire stellar mass within their Hubble time

  9. Variabilities of Low-Latitude Migrating and Nonmigrating Tides in GPS-TEC and TIMED-SABER Temperature During the Sudden Stratospheric Warming Event of 2013

    NASA Astrophysics Data System (ADS)

    Sridharan, S.

    2017-10-01

    The Global Positioning System deduced total electron content (TEC) data at 15°N (geomagnetic), which is the crest region of equatorial ionization anomaly, are used to study tidal variabilities during the 2013 sudden stratospheric warming (SSW) event. The results from space-time spectral analysis reveal that the amplitudes of migrating diurnal (DW1) and semidiurnal (SW2) tides are larger than those of nonmigrating tides. After the SSW onset, the amplitudes of DW1, SW2, SW1, and DS0 increase. Moreover, they show 16 day variations similar to the periodicity of the high-latitude stratospheric planetary wave (PW), suggesting that the nonmigrating tides (SW1 and DS0) are possibly generated due to nonlinear interaction of migrating tides with PW. Similar spectral analysis on temperature at 10°N obtained from the Sounding of Atmosphere by Broadband Emission Radiometry (SABER) shows that the SW2 enhances at stratospheric heights and the SW2 is more dominant at 80-90 km, but its amplitude decreases around 100 km. The amplitudes of nonmigrating tides become comparable to those of SW2 around 100 km, and their contribution becomes increasingly important at higher heights. This suggests that the nonlinear interaction between migrating tides and PW occurs at low-latitude upper mesospheric heights, as SW2 exhibits 16 day periodicity in SABER temperature at 100 km as observed in TEC. Besides, it is observed that the eastward propagating tides are less dominant than westward propagating tides in both TEC and SABER temperatures.

  10. Seismo-electromagnetic anomalies observed by Fomosat-1 and GIM TEC during January 27 1999 to July 2004

    NASA Astrophysics Data System (ADS)

    Yu, C. Y.; Liu, J. Y. G.

    2014-12-01

    In this study, we examine the pre-earthquake ionospheric anomalies (PEIAs) by the electron density (Ne) and ion temperature (Ti) observed by FORMOSAT-1 (ROCSAT-1) satellite during magnitude greater than 7.0 worldwide earthquakes during 1999-2004. Meanwhile, PEIAs is also currently investigated to have a better understanding of the spatial distribution of the ROCSAT-1 SIPs. Total electron density (TEC) of the global ionosphere map (GIM) confirm that the anomalous feature appear near the epicenters before the earthquakes.

  11. SHPTS: towards a new method for generating precise global ionospheric TEC map based on spherical harmonic and generalized trigonometric series functions

    NASA Astrophysics Data System (ADS)

    Li, Zishen; Yuan, Yunbin; Wang, Ningbo; Hernandez-Pajares, Manuel; Huo, Xingliang

    2015-04-01

    To take maximum advantage of the increasing Global Navigation Satellite Systems (GNSS) data to improve the accuracy and resolution of global ionospheric TEC map (GIM), an approach, named Spherical Harmonic plus generalized Trigonometric Series functions (SHPTS), is proposed by integrating the spherical harmonic and the generalized trigonometric series functions on global and local scales, respectively. The SHPTS-based GIM from January 1st, 2001 to December 31st, 2011 (about one solar cycle) is validated by the ionospheric TEC from raw global GPS data, the GIM released by the current Ionospheric Associate Analysis Center (IAAC), the TOPEX/Poseidon satellite and the DORIS. The present results show that the SHPTS-based GIM over the area where no real data are available has the same accuracy level (approximately 2-6 TECu) to that released by the current IAAC. However, the ionospheric TEC in the SHPTS-based GIM over the area covered by real data is more accurate (approximately 1.5 TECu) than that of the GIM (approximately 3.0 TECu) released by the current IAAC. The external accuracy of the SHPTS-based GIM validated by the TOPEX/Poseidon and DORIS is approximately 2.5-5.5 and 1.5-4.5 TECu, respectively. In particular, the SHPTS-based GIM is the best or almost the best ranked, along with those of JPL and UPC, when they are compared with TOPEX/Poseidon measurements, and the best (in addition to UPC) when they are validated with DORIS data. With the increase in the number of GNSS satellites and contributing stations, the performance of the SHPTS-based GIM can be further improved. The SHPTS-based GIM routinely calculated using global GPS, GLONASS and BDS data will be found at the website http://www.gipp.org.cn.

  12. Prediction of post-sunset ESF based on the strength and asymmetry of EIA from ground based TEC measurements

    NASA Astrophysics Data System (ADS)

    Thampi, S. V.; Ravindran, S.; Devasia, C. V.; Pant, T. K.; Sreelatha, P.; Sridharan, R.

    The Coherent Radio Beacon Experiment (CRABEX) is aimed at investigating the equatorial ionospheric processes like the Equatorial Ionization Anomaly (EIA) and Equatorial Spread F (ESF) and their inter relationships. As a part of CRABEX program, a network of six stations covering the region from Trivandrum (8.5°N) to Nainital (29.3°N) is set up along the 77-78° E meridian. These ground receivers basically measure the slant Total Electron Content (TEC) along the line of sight from the Low Earth Orbiting satellites (NIMS). These simultaneous TEC measurements are inverted to obtain the tomographic image of the latitudinal distribution of electron densities in the meridional plane. In this paper, the tomographic images of the equatorial ionosphere along the 77-78°E meridian are presented. The crest intensities in the southern and northern hemispheres also show significant differences with seasons, showing the variability in the EIA asymmetry. The evening images give an indication of the prevailing electrodynamical conditions on different days, preceding the occurrence/non-occurrence of ESF. Apart from this, the single station TEC measurements from the Trivandrum station itself is used to estimate the EIA strength and asymmetry. Since this station is situated at the trough of the EIA, right over the dip equator, the latitudinal gradients on both northern (N) and southern (S) sides can be used to compute the EIA strength and asymmetry. These two parameters, obtained well ahead of the onset time of ESF, are shown to have a definite role on the subsequent ESF activity. Hence, both these factors are combined to define a new `forecast parameter' for the generation of ESF. It has been shown that this parameter can uniquely define the state of the `background ionosphere' conducive for the generation of ESF irregularities as early as 1600 IST. A critical value for the `forecast parameter' has been identified such that when the estimated value for `forecast parameter' exceeds

  13. An AzTEC 1.1mm Survey of a Highly-biased Extragalactic Field Tracing Accelerated Galaxy Formation at z 3.8 towards 4C41.17

    NASA Astrophysics Data System (ADS)

    Hughes, David; Ade, P. A.; Aretxaga, I.; Austermann, J.; Bock, J. J.; Dunlop, J.; Gaztanagal, E.; Ivison, R.; Kang, Y.; Kim, S.; Lowenthal, J.; Mauskopf, P.; Montana, A.; Plionis, M.; Scott, K.; Smail, I.; Stevens, J.; Wagg, J.; Wilson, G.; Yun, M.

    2006-12-01

    Aztec has recently conducted a sensitive, wide-area (300 sq. arcmin's) continuum survey at 1.1mm using the 15-m James Clerk Maxwell Telescope towards 4C41.17, a powerful high-redshift (z 3.8) radio galaxy. These Aztec data, which cover an area >40 times larger than our previous SCUBA survey, reveal a significant over-density of luminous, massive dust-enshrouded galaxies, compared to the results from lower-redshift blank-field sub-mm surveys. One natural interpretation of these new AzTEC data is that the over-density is tracing a large (5 x 5 Mpc) "proto-cluster" structure at z 3.8 associated with the environment of 4C41.17, within which the formation of ultra-luminous starburst galaxies (with rest-frame FIR luminosities >5 x 10^12 Lsun or SFRs > 500 Msun/yr) is taking place at an accelerated rate. Proving the physical association of these massive optically-faint starbursts with the environment of this high-z AGN, and not with the blank-field sub-mm population, for which 50% of the population lies at 1.9 < z < 2.9, remains an outstanding problem. In this presentation we will describe the AzTEC survey, the empirical evidence for this protocluster structure in the early universe, and the planned multi-wavelength follow-up observations of the brightest AzTEC sources towards 4C41.17 that may demonstrate that we are witnessing accelerated galaxy formation, via an increased rate of merging gas-rich galaxies within a rapidly-developing gravitational potential. AzTEC is one of the suite of instruments destined for the 50-m Large Millimeter Telescope (LMT). We will conclude this presentation with a summary of future LMT observations that will trace the evolution of obscured starformation in the dynamic environments towards a significant sample of intermediate and high-z powerful AGN with greater sensitivity and spatial resolution.

  14. An Adaptive Network-based Fuzzy Inference System for the detection of thermal and TEC anomalies around the time of the Varzeghan, Iran, (Mw = 6.4) earthquake of 11 August 2012

    NASA Astrophysics Data System (ADS)

    Akhoondzadeh, M.

    2013-09-01

    Anomaly detection is extremely important for forecasting the date, location and magnitude of an impending earthquake. In this paper, an Adaptive Network-based Fuzzy Inference System (ANFIS) has been proposed to detect the thermal and Total Electron Content (TEC) anomalies around the time of the Varzeghan, Iran, (Mw = 6.4) earthquake jolted in 11 August 2012 NW Iran. ANFIS is the famous hybrid neuro-fuzzy network for modeling the non-linear complex systems. In this study, also the detected thermal and TEC anomalies using the proposed method are compared to the results dealing with the observed anomalies by applying the classical and intelligent methods including Interquartile, Auto-Regressive Integrated Moving Average (ARIMA), Artificial Neural Network (ANN) and Support Vector Machine (SVM) methods. The duration of the dataset which is comprised from Aqua-MODIS Land Surface Temperature (LST) night-time snapshot images and also Global Ionospheric Maps (GIM), is 62 days. It can be shown that, if the difference between the predicted value using the ANFIS method and the observed value, exceeds the pre-defined threshold value, then the observed precursor value in the absence of non seismic effective parameters could be regarded as precursory anomaly. For two precursors of LST and TEC, the ANFIS method shows very good agreement with the other implemented classical and intelligent methods and this indicates that ANFIS is capable of detecting earthquake anomalies. The applied methods detected anomalous occurrences 1 and 2 days before the earthquake. This paper indicates that the detection of the thermal and TEC anomalies derive their credibility from the overall efficiencies and potentialities of the five integrated methods.

  15. (Sub)millimetre interferometric imaging of a sample of COSMOS/AzTEC submillimetre galaxies. III. Environments

    NASA Astrophysics Data System (ADS)

    Smolčić, V.; Miettinen, O.; Tomičić, N.; Zamorani, G.; Finoguenov, A.; Lemaux, B. C.; Aravena, M.; Capak, P.; Chiang, Y.-K.; Civano, F.; Delvecchio, I.; Ilbert, O.; Jurlin, N.; Karim, A.; Laigle, C.; Le Fèvre, O.; Marchesi, S.; McCracken, H. J.; Riechers, D. A.; Salvato, M.; Schinnerer, E.; Tasca, L.; Toft, S.

    2017-01-01

    We investigate the environment of 23 submillimetre galaxies (SMGs) drawn from a signal-to-noise (S/N)-limited sample of SMGs originally discovered in the James Clerk Maxwell Telescope (JCMT)/AzTEC 1.1 mm continuum survey of a Cosmic Evolution Survey (COSMOS) subfield and then followed up with the Submillimetre Array and Plateau de Bure Interferometer at 890 μm and 1.3 mm, respectively. These SMGs already have well-defined multiwavelength counterparts and redshifts. We also analyse the environments of four COSMOS SMGs spectroscopically confirmed to lie at redshifts zspec > 4.5, and one at zspec = 2.49 resulting in a total SMG sample size of 28. We search for overdensities using the COSMOS photometric redshifts based on over 30 UV-NIR photometric measurements including the new UltraVISTA data release 2 and Spitzer/SPLASH data, and reaching an accuracy of σΔz/ (1 + z) = 0.0067 (0.0155) at z < 3.5 (>3.5). To identify overdensities we apply the Voronoi tessellation analysis, and estimate the redshift-space overdensity estimator δg as a function of distance from the SMG and/or overdensity centre. We test and validate our approach via simulations, X-ray detected groups or clusters, and spectroscopic verifications using VUDS and zCOSMOS catalogues which show that even with photometric redshifts in the COSMOS field we can efficiently retrieve overdensities out to z ≈ 5. Our results yield that 11 out of 23 (48%) JCMT/AzTEC 1.1 mm SMGs occupy overdense environments. Considering the entire JCMT/AzTEC 1.1 mm S/N ≥ 4 sample and taking the expected fraction of spurious detections into account, this means that 35-61% of the SMGs in the S/N-limited sample occupy overdense environments. We perform an X-ray stacking analysis in the 0.5-2 keV band using a 32″ aperture and our SMG positions, and find statistically significant detections. For our z < 2 subsample we find an average flux of (4.0 ± 0.8) × 10-16 erg s-1 cm-2 and a corresponding total mass of M200 = 2.8 × 1013M

  16. Low and Mid-Latitude Ionospheric Irregularities Studies Using TEC and Radio Scintillation Data from the CITRIS Radio Beacon Receiver in Low-Earth-Orbit

    NASA Astrophysics Data System (ADS)

    Siefring, C. L.; Bernhardt, P. A.; Huba, J.; Krall, J.; Roddy, P. A.

    2009-12-01

    Unique data on ionospheric plasma irregularities from the Naval Research Laboratory (NRL) CITRIS (Scintillation and TEC Receiver in Space) instrument will be presented. CITRIS is a multi-band receiver that recorded TEC (Total Electron Content) and radio scintillations from Low-Earth Orbit (LEO) on STPSat1. The 555+/5 km altitude 35° inclination orbit covers low and mid-latitudes. The measurements require propagation from a transmitter to a receiver through the F-region plasma. CITRIS used both 1) satellite beacons in LEO, such as the NRL CERTO (Coherent Electromagnetic Radio TOmography) beacons and 2) the global network of ground-based DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellite) beacons. The TEC measurements allow for tracking of ionospheric disturbances and irregularities while the measurements of scintillations can simultaneously characterize their effects. CITRIS was operated in a complementary fashion with the C/NOFS (Communication/Navigations Outages Forecasting System) satellite during most of its first year of operations. C/NOFS carries a three-frequency 150/400/1067 MHz CERTO beacon and is dedicated to the study of Spread-F. In the case of Spread-F, ionospheric irregularities start with large scale size density gradients (100s of km) and cascade through complex processes to short scale sizes (10s of meters). It is typically the 100m-1km scale features that harm communication and navigation systems through scintillations. A multi-sensor approach is needed to completely understand this complex system, such as, the combination of CITRIS remote radio sensing and C/NOFS in-situ data. Several types of irregularities have been studied including Spread-F and the newly discovered dawn-side depletions. Comparisons with the physics based SAMI3 model are being performed to help our understanding of the morphology of the irregularities.

  17. A new life for a 10-year old MueTec2010 CD measurement system: the ultimate precision upgrade with additional film thickness measurement capability

    NASA Astrophysics Data System (ADS)

    Cassol, Gian Luca; Bianucci, Giovanni; Murai, Shiaki; Falk, Günther; Scheuring, Gerd; Döbereiner, Stefan; Brück, Hans-Jürgen

    2006-06-01

    A 10-year old MueTec2010, white light CD measurement system, installed at DNP Photomask Europe and previously owned by STMicroelectronics, has been upgraded to fulfill the high-end optical CD measurement requirements, and to add the film thickness measurement capability. That is the ultimate upgrade, consisting of two new computers with WINDOWS 2000 operating system, a new 150X measurement objective, a new 16-bit CCD digital camera, a new tube lens for the old Leica Ergoplan microscope, and the NanoStar software with the pattern recognition option. The upgrade yielded an average 45% repeatability improvement for isolated and dense lines and spaces, with 1.2nm average repeatability in a 0.3-10μm CD nominal range. Contact holes report an average 50% repeatability improvement, with 2.5nm average repeatability. The improved precision allows a +/-2-nm CD calibration and correlation down to 0.4μm CD nominal. Overall, the upgraded MueTec2010 shows same or better performance than the already installed Leica LWM250UV CD measurement system, despite the longer illumination wavelength of the former. The improved short and long term repeatability reduced the Gauge RandR figure from 24% to 11% at +/-20nm tolerance, which qualifies the system for high-end binary mask down to 0.5μm CD nominal. The feasibility to calibrate the system for 248nm Molybdenum Silicide Phase Shifting Masks is currently being investigated. In addition to that, the new measurement algorithms, the capability to take multiple measurements within the FOV, and the pattern recognition capability included in the NanoStar software gave a 75% throughput boost to the fully automated macros for the weekly calibration tests of the laser writing tools, compared to the LWM250UV run time. With little additional hardware and software, the system has also been upgraded to include the film thickness measurement capability for the PSM resist coating process (2nd exposure), without the need for a dedicated, more expensive

  18. Homogeneous real-time detection of single-nucleotide polymorphisms by strand displacement amplification on the BD ProbeTec ET system.

    PubMed

    Wang, Sha-Sha; Thornton, Keith; Kuhn, Andrew M; Nadeau, James G; Hellyer, Tobin J

    2003-10-01

    The BD ProbeTec ET System is based on isothermal strand displacement amplification (SDA) of target nucleic acid coupled with homogeneous real-time detection using fluorescent probes. We have developed a novel, rapid method using this platform that incorporates a universal detection format for identification of single-nucleotide polymorphisms (SNPs) and other genotypic variations. The system uses a common pair of fluorescent Detector Probes in conjunction with unlabeled allele-specific Adapter Primers and a universal buffer chemistry to permit analysis of multiple SNP loci under generic assay conditions. We used Detector Probes labeled with different dyes to facilitate differentiation of two alternative alleles in a single reaction with no postamplification manipulation. We analyzed six SNPs within the human beta(2)-adrenergic receptor (beta(2)AR) gene, using whole blood, buccal swabs, and urine samples, and compared results with those obtained by DNA sequencing. Unprocessed whole blood was successfully genotyped with as little as 0.1-1 micro L of sample per reaction. All six beta(2)AR assays were able to accommodate >/==" BORDER="0">20 micro L of unprocessed whole blood. For the 14 individuals tested, genotypes determined with the six beta(2)AR assays agreed with DNA sequencing results. SDA-based allelic differentiation on the BD ProbeTec ET System can detect SNPs rapidly, using whole blood, buccal swabs, or urine.

  19. Supporting Heart Failure Patient Transitions From Acute to Community Care With Home Telemonitoring Technology: A Protocol for a Provincial Randomized Controlled Trial (TEC4Home).

    PubMed

    2016-12-18

    Seniors with chronic diseases such as heart failure have complex care needs. They are vulnerable to their condition deteriorating and, without timely intervention, may require multiple emergency department visits and/or repeated hospitalizations. Upon discharge, the transition from the emergency department to home can be a vulnerable time for recovering patients with disruptions in the continuity of care. Remote monitoring of heart failure patients using home telemonitoring, coupled with clear communication protocols between health care professionals, can be effective in increasing the safety and quality of care for seniors with heart failure discharged from the emergency department. The aim of the Telehealth for Emergency-Community Continuity of Care Connectivity via Home Telemonitoring (TEC4Home) study is to generate evidence through a programmatic evaluation and a clinical trial to determine how home telemonitoring may improve care and increase patient safety during the transition of care and determine how it is best implemented to support patients with heart failure within this context. This 4-year project consists of 3 studies to comprehensively evaluate the outcomes and effectiveness of TEC4Home. Study 1 is a feasibility study with 90 patients recruited from 2 emergency department sites to test implementation and evaluation procedures. Findings from the feasibility study will be used to refine protocols for the larger trial. Study 2 is a cluster randomized controlled trial that will include 30 emergency department sites and 900 patients across British Columbia. The primary outcome of the randomized controlled trial will be emergency department revisits and hospital readmission rates. Secondary outcomes include health care resource utilization/costs, communication between members of the care team, and patient quality of life. Study 3 will run concurrently to study 2 and test the effectiveness of predictive analytic software to detect patient deterioration

  20. Wide-field Imaging Survey of Dust Continuum Emissions at lambda = 1.1 mm toward the Chamaeleon and Lupus Regions with AzTEC on ASTE

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

    Momose, Munetake; Hiramatsu, Masaaki; Tsukagoshi, Takashi

    2009-08-05

    We carried out an imaging survey of dust continuum emissions toward the Chamaeleon and Lupus regions. Observations were made with the 144-element bolometer array camera AzTEC mounted on the 10-meter sub-millimeter telescope ASTE during 2007-2008. The preliminary results of disk search and the cloud structure of Lupus III are presented.

  1. Study protocol: The Technology-Enhanced Coaching (TEC) program to improve diabetes outcomes – A randomized controlled trial

    PubMed Central

    Heisler, Michele; Mase, Rebecca; Brown, Brianne; Wilson, Shayla; Reeves, Pamela J.

    2017-01-01

    Background Racial and ethnic minority adults with diabetes living in under-resourced communities face multiple barriers to sustaining self-management behaviors necessary to improve diabetes outcomes. Peer support and decision support tools each have been associated with improved diabetes outcomes. Methods 289 primarily African American adults with poor glycemic control will be recruited from the Detroit Veteran’s Administration Hospital and randomized to Technology-Enhanced Coaching (TEC) or Peer Coaching alone. Participants in both arms will be assigned a peer coach trained in autonomy-supportive approaches. Coaches are diabetes patients with prior poor glycemic control who now have good control. All participants meet face-to-face initially with their coach to review diabetes education materials and develop an action plan. Educational materials in the TEC arm are delivered via a web-based, educational tool tailored with each participant’s personalized health data (iDecide). Over the next six months, Coaches call their assigned participants once a week to provide support for weekly action steps. Data are also collected on an Observational Control group with no contact with study staff. Changes in A1c, blood pressure, other patient-centered outcomes and mediators and moderators of intervention effects will be assessed. Discussion Tailored e-Health tools with educational content may enhance the effectiveness of peer coaching programs to better prepare patients to set self-management goals, identify action plans, and discuss treatment options with their health care providers. The study will provide insights for scalable self-management support programs for diabetes and chronic illnesses that require high levels of sustained patient self-management. PMID:28132876

  2. A Real-Time Earthquake Precursor Detection Technique Using TEC from a GPS Network

    NASA Astrophysics Data System (ADS)

    Alp Akyol, Ali; Arikan, Feza; Arikan, Orhan

    2016-07-01

    Anomalies have been observed in the ionospheric electron density distribution prior to strong earthquakes. However, most of the reported results are obtained by earthquake analysis. Therefore, their implementation in practice is highly problematic. Recently, a novel earthquake precursor detection technique based on spatio-temporal analysis of Total Electron Content (TEC) data obtained from Turkish National Permanent GPS Network (TNPGN) is developed by IONOLAB group (www.ionolab.org). In the present study, the developed detection technique is implemented in a causal setup over the available data set in test phase that enables the real time implementation. The performance of the developed earthquake prediction technique is evaluated by using 10 fold cross validation over the data obtained in 2011. Among the 23 earthquakes that have magnitudes higher than 5, the developed technique can detect precursors of 14 earthquakes while producing 8 false alarms. This study is supported by TUBITAK 115E915 and Joint TUBITAK 114E092 and AS CR 14/001 projects.

  3. A MASSIVE MOLECULAR GAS RESERVOIR IN THE z = 5.3 SUBMILLIMETER GALAXY AzTEC-3

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

    Riechers, Dominik A.; Scoville, Nicholas Z.; Capak, Peter L.

    2010-09-10

    We report the detection of CO J = 2{yields}1, 5{yields}4, and 6{yields}5 emission in the highest-redshift submillimeter galaxy (SMG) AzTEC-3 at z = 5.298, using the Expanded Very Large Array and the Plateau de Bure Interferometer. These observations ultimately confirm the redshift, making AzTEC-3 the most submillimeter-luminous galaxy in a massive z {approx_equal} 5.3 protocluster structure in the COSMOS field. The strength of the CO line emission reveals a large molecular gas reservoir with a mass of 5.3 x 10{sup 10}({alpha}{sub CO}/0.8) M {sub sun}, which can maintain the intense 1800 M {sub sun} yr{sup -1} starburst in this systemmore » for at least 30 Myr, increasing the stellar mass by up to a factor of six in the process. This gas mass is comparable to 'typical' z {approx} 2 SMGs and constitutes {approx_gt}80% of the baryonic mass (gas+stars) and 30%-80% of the total (dynamical) mass in this galaxy. The molecular gas reservoir has a radius of <4 kpc and likely consists of a 'diffuse', low-excitation component, containing (at least) 1/3 of the gas mass (depending on the relative conversion factor {alpha}{sub CO}), and a 'dense', high-excitation component, containing {approx}2/3 of the mass. The likely presence of a substantial diffuse component besides highly excited gas suggests different properties between the star-forming environments in z > 4 SMGs and z > 4 quasar host galaxies, which perhaps trace different evolutionary stages. The discovery of a massive, metal-enriched gas reservoir in an SMG at the heart of a large z = 5.3 protocluster considerably enhances our understanding of early massive galaxy formation, pushing back to a cosmic epoch where the universe was less than 1/12 of its present age.« less

  4. Study on ABO and RhD blood grouping: Comparison between conventional tile method and a new solid phase method (InTec Blood Grouping Test Kit).

    PubMed

    Yousuf, R; Abdul Ghani, S A; Abdul Khalid, N; Leong, C F

    2018-04-01

    'InTec Blood Grouping Test kit' using solid-phase technology is a new method which may be used at outdoor blood donation site or at bed side as an alternative to the conventional tile method in view of its stability at room temperature and fulfilled the criteria as point of care test. This study aimed to compare the efficiency of this solid phase method (InTec Blood Grouping Test Kit) with the conventional tile method in determining the ABO and RhD blood group of healthy donors. A total of 760 voluntary donors who attended the Blood Bank, Penang Hospital or offsite blood donation campaigns from April to May 2014 were recruited. The ABO and RhD blood groups were determined by the conventional tile method and the solid phase method, in which the tube method was used as the gold standard. For ABO blood grouping, the tile method has shown 100% concordance results with the gold standard tube method, whereas the solid-phase method only showed concordance result for 754/760 samples (99.2%). Therefore, for ABO grouping, tile method has 100% sensitivity and specificity while the solid phase method has slightly lower sensitivity of 97.7% but both with good specificity of 100%. For RhD grouping, both the tile and solid phase methods have grouped one RhD positive specimen as negative each, thus giving the sensitivity and specificity of 99.9% and 100% for both methods respectively. The 'InTec Blood Grouping Test Kit' is suitable for offsite usage because of its simplicity and user friendliness. However, further improvement in adding the internal quality control may increase the test sensitivity and validity of the test results.

  5. GPS TEC Fluctuations in the Low and High Latitudes During the 2015 St. Patrick`s Day Storm

    NASA Astrophysics Data System (ADS)

    Chung, Jong-Kyun; Hong, Junseok; Yoo, Sung-Moon; Kim, Jeong-Han; Jee, Geonhwa; Hegai, Valery V.

    2017-12-01

    As a part of collaborative efforts to understand ionospheric irregularities, the Korea ionospheric scintillation sites (KISS) network has been built based on global positioning system (GPS) receivers with sampling rates higher than 1 Hz. We produce the rate of TEC index (ROTI) to represent GPS TEC fluctuations related to ionospheric irregularities. In the KISS network, two ground-based GPS sites at Kiruna (marker: KIRN; geographic: 67.9° N, 21.4° E; geomagnetic: 65.2° N) and Chuuk (marker: CHUK; geographic: 7.5° N, 151.9° E; geomagnetic: 0.4° N) were selected to evaluate the ROTI value for ionospheric irregularities during the occurrence of the 2015 St. Patrick’s Day storm. The KIRN ROTI values in the aurora region appear to be generally much higher than the CHUK ROTI values in the EIA region. The CHUK ROTI values increased to 0.5 TECU/min around UT=13:00 (LT=23:00) on March 16 in the quiet geomagnetic condition. On March 17, 2015, CHUK ROTI values more than 1.0 TECU/min were measured between UT=9:00 and 12:00 (LT=19:00 and 22:00) during the first main phase of the St. Patrick’s Day storm. This may be due to ionospheric irregularities by increased pre-reversal enhancement (PRE) after sunset during the geomagnetic storm. Post-midnight, the CHUK ROTI showed two peaks of 0.5 TECU/min and 0.3 TECU/min near UT=15:00 (LT=01:00) and UT=18:00 (LT=04:00) at the second main phase. The KIRN site showed significant peaks of ROTI around geomagnetic latitude=63.3° N and MLT=15:40 on the same day. These can be explained by enhanced ionospheric irregularities in the auroral oval at the maximum of AE index

  6. The ultraviolet detection component based on Te-Cs image intensifier

    NASA Astrophysics Data System (ADS)

    Qian, Yunsheng; Zhou, Xiaoyu; Wu, Yujing; Wang, Yan; Xu, Hua

    2017-05-01

    Ultraviolet detection technology has been widely focused and adopted in the fields of ultraviolet warning and corona detection for its significant value and practical meaning. The component structure of ultraviolet ICMOS, imaging driving and the photon counting algorithm are studied in this paper. Firstly, the one-inch and wide dynamic range CMOS chip with the coupling optical fiber panel is coupled to the ultraviolet image intensifier. The photocathode material in ultraviolet image intensifier is Te-Cs, which contributes to the solar blind characteristic, and the dual micro-channel plates (MCP) structure ensures the sufficient gain to achieve the single photon counting. Then, in consideration of the ultraviolet detection demand, the drive circuit of the CMOS chip is designed and the corresponding program based on Verilog language is written. According to the characteristics of ultraviolet imaging, the histogram equalization method is applied to enhance the ultraviolet image and the connected components labeling way is utilized for the ultraviolet single photon counting. Moreover, one visible light video channel is reserved in the ultraviolet ICOMS camera, which can be used for the fusion of ultraviolet and visible images. Based upon the module, the ultraviolet optical lens and the deep cut-off solar blind filter are adopted to construct the ultraviolet detector. At last, the detection experiment of the single photon signal is carried out, and the test results are given and analyzed.

  7. The AzTEC millimeter-wave camera: Design, integration, performance, and the characterization of the (sub-)millimeter galaxy population

    NASA Astrophysics Data System (ADS)

    Austermann, Jason Edward

    One of the primary drivers in the development of large format millimeter detector arrays is the study of sub-millimeter galaxies (SMGs) - a population of very luminous high-redshift dust-obscured starbursts that are widely believed to be the dominant contributor to the Far-Infrared Background (FIB). The characterization of such a population requires the ability to map large patches of the (sub-)millimeter sky to high sensitivity within a feasible amount of time. I present this dissertation on the design, integration, and characterization of the 144-pixel AzTEC millimeter-wave camera and its application to the study of the sub-millimeter galaxy population. In particular, I present an unprecedented characterization of the "blank-field" (fields with no known mass bias) SMG number counts by mapping over 0.5 deg^2 to 1.1mm depths of ~1mJy - a previously unattained depth on these scales. This survey provides the tightest SMG number counts available, particularly for the brightest and rarest SMGs that require large survey areas for a significant number of detections. These counts are compared to the predictions of various models of the evolving mm/sub-mm source population, providing important constraints for the ongoing refinement of semi-analytic and hydrodynamical models of galaxy formation. I also present the results of an AzTEC 0.15 deg^2 survey of the COSMOS field, which uncovers a significant over-density of bright SMGs that are spatially correlated to foreground mass structures, presumably as a result of gravitational lensing. Finally, I compare the results of the available SMG surveys completed to date and explore the effects of cosmic variance on the interpretation of individual surveys.

  8. Variation of TEC and related parameters over the Indian EIA region from ground and space based GPS observations during the low solar activity period of May 2007-April 2008

    NASA Astrophysics Data System (ADS)

    Chakravarty, S. C.; Nagaraja, Kamsali; Jakowski, N.

    2017-03-01

    The annual variations of ionospheric Total Electron Content (TEC), F-region peak ionisation (NmF2) and the ionospheric slab thickness (τ) over the Indian region during the low solar activity period of May 2007-April 2008 have been studied. For this purpose the ground based TEC data obtained from GAGAN measurements and the space based data from GPS radio occultation technique using CHAMP have been utilised. The results of these independent measurements are combined to derive additional parameters such as the equivalent slab thickness of the total and the bottom-side ionospheric regions (τT and τB). The one year hourly average values of all these parameters over the ionospheric anomaly latitude region (10-26°N) are presented here along with the statistical error estimates. It is expected that these results are potentially suited to be used as base level values during geomagnetically quiet and undisturbed solar conditions.

  9. Star and Dust Formation Activities in AzTEC-3, a Starburst Galaxy at z = 5.3

    NASA Astrophysics Data System (ADS)

    Dwek, Eli; Staguhn, Johannes G.; Arendt, Richard G.; Capak, Peter L.; Kovacs, Attila; Benford, Dominic J.; Fixsen, Dale; Karim, Alexander; Leclercq, Samuel; Maher, Stephen F.; Moseley, Samuel H.; Schinnerer, Eva; Sharp, Elmer H.

    2011-09-01

    Analyses of high-redshift ultraluminous infrared (IR) galaxies traditionally use the observed optical to submillimeter spectral energy distribution (SED) and estimates of the dynamical mass as observational constraints to derive the star formation rate (SFR), the stellar mass, and age of these objects. An important observational constraint neglected in the analysis is the mass of dust giving rise to the IR emission. In this paper we add this constraint to the analysis of AzTEC-3. Adopting an upper limit to the mass of stars and a bolometric luminosity for this object, we construct different stellar and chemical evolutionary scenarios, constrained to produce the inferred dust mass and observed luminosity before the associated stellar mass exceeds the observational limit. We use the PÉGASE population synthesis code and a chemical evolution model to follow the evolution of the galaxy's SED and its stellar and dust masses as a function of galactic age for seven different stellar initial mass functions (IMFs). We find that the model with a Top Heavy IMF provided the most plausible scenario consistent with the observational constraints. In this scenario the dust formed over a period of ~200 Myr, with an SFR of ~500 M sun yr-1. These values for the age and SFR in AzTEC-3 are significantly higher and lower, respectively, from those derived without the dust mass constraint. However, this scenario is not unique, and others cannot be completely ruled out because of the prevailing uncertainties in the age of the galaxy, its bolometric luminosity, and its stellar and dust masses. A robust result of our models is that all scenarios require most of the radiating dust mass to have been accreted in molecular clouds. Our new procedure highlights the importance of a multiwavelength approach, and of the use of dust evolution models in constraining the age and the star formation activity and history in galaxies.

  10. STAR AND DUST FORMATION ACTIVITIES IN AzTEC-3, A STARBURST GALAXY AT z = 5.3

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

    Dwek, Eli; Staguhn, Johannes G.; Arendt, Richard G.

    2011-09-01

    Analyses of high-redshift ultraluminous infrared (IR) galaxies traditionally use the observed optical to submillimeter spectral energy distribution (SED) and estimates of the dynamical mass as observational constraints to derive the star formation rate (SFR), the stellar mass, and age of these objects. An important observational constraint neglected in the analysis is the mass of dust giving rise to the IR emission. In this paper we add this constraint to the analysis of AzTEC-3. Adopting an upper limit to the mass of stars and a bolometric luminosity for this object, we construct different stellar and chemical evolutionary scenarios, constrained to producemore » the inferred dust mass and observed luminosity before the associated stellar mass exceeds the observational limit. We use the PEGASE population synthesis code and a chemical evolution model to follow the evolution of the galaxy's SED and its stellar and dust masses as a function of galactic age for seven different stellar initial mass functions (IMFs). We find that the model with a Top Heavy IMF provided the most plausible scenario consistent with the observational constraints. In this scenario the dust formed over a period of {approx}200 Myr, with an SFR of {approx}500 M{sub sun} yr{sup -1}. These values for the age and SFR in AzTEC-3 are significantly higher and lower, respectively, from those derived without the dust mass constraint. However, this scenario is not unique, and others cannot be completely ruled out because of the prevailing uncertainties in the age of the galaxy, its bolometric luminosity, and its stellar and dust masses. A robust result of our models is that all scenarios require most of the radiating dust mass to have been accreted in molecular clouds. Our new procedure highlights the importance of a multiwavelength approach, and of the use of dust evolution models in constraining the age and the star formation activity and history in galaxies.« less

  11. HiTEC: a connectionist model of the interaction between perception and action planning.

    PubMed

    Haazebroek, Pascal; Raffone, Antonino; Hommel, Bernhard

    2017-11-01

    Increasing evidence suggests that perception and action planning do not represent separable stages of a unidirectional processing sequence, but rather emerging properties of highly interactive processes. To capture these characteristics of the human cognitive system, we have developed a connectionist model of the interaction between perception and action planning: HiTEC, based on the Theory of Event Coding (Hommel et al. in Behav Brain Sci 24:849-937, 2001). The model is characterized by representations at multiple levels and by shared representations and processes. It complements available models of stimulus-response translation by providing a rationale for (1) how situation-specific meanings of motor actions emerge, (2) how and why some aspects of stimulus-response translation occur automatically and (3) how task demands modulate sensorimotor processing. The model is demonstrated to provide a unitary account and simulation of a number of key findings with multiple experimental paradigms on the interaction between perception and action such as the Simon effect, its inversion (Hommel in Psychol Res 55:270-279, 1993), and action-effect learning.

  12. The spatio-temporal characteristics of the wave structure excited by the solar terminator as deduced from TEC measurements at the global GPS network

    NASA Astrophysics Data System (ADS)

    Afraimovich, E.

    2009-04-01

    Recent investigations have shown that movement of the solar terminator (ST) causes generation of acoustic-gravity waves (AGW), turbulence and instabilities in the ionosphere plasma. Among all the sources of gravity waves, the moving ST has a special status, since it is a predictable phenomenon, whose characteristics are well known. Considering the ST as a stable and repetitive source of AGW, one can derive information about atmospheric conditions from the response of the medium to this input. The great variety of ST-linked phenomena in the atmosphere gave rise to a number of studies on the analysis of ionosphere parameter variations obtained by different ionosphere sounding methods. However, virtually all experimental data were obtained using indirect methods for analyzing the spectrum of ionosphere parameter variations, which can result from a number of factors. This causes difficulties in the reliable identification of ST-linked AGW, because in general case AGW can be generated by different sources either of natural or of anthropogenic origin. To identify ST-generated wave disturbances it is insufficient to register the time dependence of ionosphere parameters or their spectrum. It is necessary to measure the spatial structure of these disturbances and to compare it with spatial-temporal characteristics of ST. Another important requirement implies the continuous, global character of observations. Using long-term (1998-2007) total electron content (TEC) measurements from the IGS GPS global network and dense networks of GPS sites in USA (CORS) and Japan (GEONET), we have obtained the first evidence for the wave structure excited by the solar terminator (ST). We have found two main types of the observed TEC disturbances: large-scale (LS) 60-min variations with amplitude of about 0.5-1 TECU and medium-scale (MS) 15-min variations with amplitude of about 0.05-0.1 TECU. The first type of disturbances was predicted in theoretical investigations and registered earlier

  13. Supporting Heart Failure Patient Transitions From Acute to Community Care With Home Telemonitoring Technology: A Protocol for a Provincial Randomized Controlled Trial (TEC4Home)

    PubMed Central

    2016-01-01

    Background Seniors with chronic diseases such as heart failure have complex care needs. They are vulnerable to their condition deteriorating and, without timely intervention, may require multiple emergency department visits and/or repeated hospitalizations. Upon discharge, the transition from the emergency department to home can be a vulnerable time for recovering patients with disruptions in the continuity of care. Remote monitoring of heart failure patients using home telemonitoring, coupled with clear communication protocols between health care professionals, can be effective in increasing the safety and quality of care for seniors with heart failure discharged from the emergency department. Objective The aim of the Telehealth for Emergency-Community Continuity of Care Connectivity via Home Telemonitoring (TEC4Home) study is to generate evidence through a programmatic evaluation and a clinical trial to determine how home telemonitoring may improve care and increase patient safety during the transition of care and determine how it is best implemented to support patients with heart failure within this context. Methods This 4-year project consists of 3 studies to comprehensively evaluate the outcomes and effectiveness of TEC4Home. Study 1 is a feasibility study with 90 patients recruited from 2 emergency department sites to test implementation and evaluation procedures. Findings from the feasibility study will be used to refine protocols for the larger trial. Study 2 is a cluster randomized controlled trial that will include 30 emergency department sites and 900 patients across British Columbia. The primary outcome of the randomized controlled trial will be emergency department revisits and hospital readmission rates. Secondary outcomes include health care resource utilization/costs, communication between members of the care team, and patient quality of life. Study 3 will run concurrently to study 2 and test the effectiveness of predictive analytic software to

  14. Optical power of VCSELs stabilized to 35 ppm/°C without a TEC

    NASA Astrophysics Data System (ADS)

    Downing, John

    2015-03-01

    This paper reports a method and system comprising a light source, an electronic method, and a calibration procedure for stabilizing the optical power of vertical-cavity surface-emitting lasers (VCSELs) and laser diodes (LDs) without the use thermoelectric coolers (TECs). The system eliminates the needs for custom interference coatings, polarization adjustments, and the exact alignment required by the optical method reported in 2013 [1]. It can precisely compensate for the effects of temperature and wavelength drift on photodiode responsivity as well as changes in VCSEL beam quality and polarization angle over a 50°C temperature range. Data obtained from light sources built with single-mode polarization-locked VCSELs demonstrate that 30 ppm/°C stability can be readily obtained. The system has advantages over TECstabilized laser modules that include: 1) 90% lower relative RMS optical power and temperature sensitivity, 2) a five-fold enhancement of wall-plug efficiency, 3) less component testing and sorting, 4) lower manufacturing costs, and 5) automated calibration in batches at time of manufacture is practical. The system is ideally suited for battery-powered environmental and in-home medical monitoring applications.

  15. Field trial of efficacy of the Leish-tec® vaccine against canine leishmaniasis caused by Leishmania infantum in an endemic area with high transmission rates.

    PubMed

    Grimaldi, Gabriel; Teva, Antonio; Dos-Santos, Claudiney B; Santos, Fernanda Nunes; Pinto, Israel de-Souza; Fux, Blima; Leite, Gustavo Rocha; Falqueto, Aloísio

    2017-01-01

    Because domestic dogs are reservoir hosts for visceral leishmaniasis (VL) in Brazil, one of the approaches used to reduce human disease incidence is to cull infected dogs. However, the results of controlled intervention trials based on serological screening of dogs and killing of seropositive animals are equivocal. A prophylactic vaccine to protect dogs from being infectious to the sand fly vector could be an effective strategy to provide sustained control. Here, we investigated whether a currently licensed commercial subunit rA2 protein-saponin vaccine (Leish-tec®) had an additional effect to dog culling on reducing the canine infectious populations. This prospective study was conducted in an L. infantum highly endemic area of southeast Brazil. At the onset of the intervention, all of the eligible dogs received through subcutaneous route a three-dose vaccine course at 21-day intervals and a booster on month 12. For the purpose of comparison, newly recruited healthy dogs were included as the exposed control group. To ascertain vaccine-induced protection, dogs were screened on clinical and serological criteria every 6 months for a 2-year follow-up period. Antibody-based tests and histopathological examination of post-mortem tissue specimens from euthanized animals were used as a marker of infection. The standardized vaccine regime, apart from being safe, was immunogenic as immunized animals responded with a pronounced production of anti-A2-specific IgG antibodies. It should be noted the mean seroconversion time for infection obtained among immunized exposed dogs (~ 18 months), which was twice as high as that for unvaccinated ones (~ 9 months). After two transmission cycles completed, the cumulative incidence of infection did differ significantly (P = 0.016) between the vaccinated (27%) and unvaccinated (42%) dogs. However, the expected efficacy for the vaccine in inducing clinical protection was not evident since 43% of vaccine recipients developed disease over

  16. Plasma bubble monitoring by TEC map and 630 nm airglow image

    NASA Astrophysics Data System (ADS)

    Takahashi, H.; Wrasse, C. M.; Otsuka, Y.; Ivo, A.; Gomes, V.; Paulino, I.; Medeiros, A. F.; Denardini, C. M.; Sant'Anna, N.; Shiokawa, K.

    2015-08-01

    Equatorial ionosphere plasma bubbles over the South American continent were successfully observed by mapping the total electron content (TECMAP) using data provided by ground-based GNSS receiver networks. The TECMAP could cover almost all of the continent within ~4000 km distance in longitude and latitude, monitoring TEC variability continuously with a time resolution of 10 min. Simultaneous observations of OI 630 nm all-sky image at Cachoeira Paulista (22.7°S, 45.0°W) and Cariri (7.4°S, 36.5°W) were used to compare the bubble structures. The spatial resolution of the TECMAP varied from 50 km to 1000 km, depending on the density of the observation sites. On the other hand, optical imaging has a spatial resolution better than 15 km, depicting the fine structure of the bubbles but covering a limited area (~1600 km diameter). TECMAP has an advantage in its spatial coverage and the continuous monitoring (day and night) form. The initial phase of plasma depletion in the post-sunset equatorial ionization anomaly (PS-EIA) trough region, followed by development of plasma bubbles in the crest region, could be monitored in a progressive way over the magnetic equator. In December 2013 to January 2014, periodically spaced bubble structures were frequently observed. The longitudinal spacing between the bubbles was around 600-800 km depending on the day. The periodic form of plasma bubbles may suggest a seeding process related to the solar terminator passage in the ionosphere.

  17. The AzTEC/SMA Interferometric Imaging Survey of Submillimeter-selected High-redshift Galaxies

    NASA Astrophysics Data System (ADS)

    Younger, Joshua D.; Fazio, Giovanni G.; Huang, Jia-Sheng; Yun, Min S.; Wilson, Grant W.; Ashby, Matthew L. N.; Gurwell, Mark A.; Peck, Alison B.; Petitpas, Glen R.; Wilner, David J.; Hughes, David H.; Aretxaga, Itziar; Kim, Sungeun; Scott, Kimberly S.; Austermann, Jason; Perera, Thushara; Lowenthal, James D.

    2009-10-01

    We present results from a continuing interferometric survey of high-redshift submillimeter galaxies (SMGs) with the Submillimeter Array, including high-resolution (beam size ~2 arcsec) imaging of eight additional AzTEC 1.1 mm selected sources in the COSMOS field, for which we obtain six reliable (peak signal-to-noise ratio (S/N) >5 or peak S/N >4 with multiwavelength counterparts within the beam) and two moderate significance (peak S/N >4) detections. When combined with previous detections, this yields an unbiased sample of millimeter-selected SMGs with complete interferometric follow up. With this sample in hand, we (1) empirically confirm the radio-submillimeter association, (2) examine the submillimeter morphology—including the nature of SMGs with multiple radio counterparts and constraints on the physical scale of the far infrared—of the sample, and (3) find additional evidence for a population of extremely luminous, radio-dim SMGs that peaks at higher redshift than previous, radio-selected samples. In particular, the presence of such a population of high-redshift sources has important consequences for models of galaxy formation—which struggle to account for such objects even under liberal assumptions—and dust production models given the limited time since the big bang.

  18. THE AzTEC/SMA INTERFEROMETRIC IMAGING SURVEY OF SUBMILLIMETER-SELECTED HIGH-REDSHIFT GALAXIES

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

    Younger, Joshua D.; Fazio, Giovanni G.; Huang Jiasheng

    We present results from a continuing interferometric survey of high-redshift submillimeter galaxies (SMGs) with the Submillimeter Array, including high-resolution (beam size approx2 arcsec) imaging of eight additional AzTEC 1.1 mm selected sources in the COSMOS field, for which we obtain six reliable (peak signal-to-noise ratio (S/N) >5 or peak S/N >4 with multiwavelength counterparts within the beam) and two moderate significance (peak S/N >4) detections. When combined with previous detections, this yields an unbiased sample of millimeter-selected SMGs with complete interferometric follow up. With this sample in hand, we (1) empirically confirm the radio-submillimeter association, (2) examine the submillimeter morphology-includingmore » the nature of SMGs with multiple radio counterparts and constraints on the physical scale of the far infrared-of the sample, and (3) find additional evidence for a population of extremely luminous, radio-dim SMGs that peaks at higher redshift than previous, radio-selected samples. In particular, the presence of such a population of high-redshift sources has important consequences for models of galaxy formation-which struggle to account for such objects even under liberal assumptions-and dust production models given the limited time since the big bang.« less

  19. Ionospheric TEC, thermospheric cooling and Σ[O/N2] compositional changes during the 6-17 March 2012 magnetic storm interval (CAWSES II)

    NASA Astrophysics Data System (ADS)

    Verkhoglyadova, O. P.; Tsurutani, B. T.; Mannucci, A. J.; Mlynczak, M. G.; Hunt, L. A.; Paxton, L. J.

    2014-08-01

    A series of four geomagnetic storms (the minimum SYM-H~-148 nT) occurred during the March 6-17, 2012 in the ascending phase of the solar cycle 24. This interval was selected by CAWSES II for its campaign. The GPS total electron content (TEC) database and JPL's Global Ionospheric Maps (GIM) were used to study vertical TEC (VTEC) for different local times and latitude ranges. The largest response to geomagnetic activity is shown in increases of the low-latitude dayside VTEC. Several GPS sites feature post-afternoon VTEC “bite-outs”. During Sudden Impulse (SI+) event on March 8th a peak daytime VTEC restores to about quiet-time values. It is shown that the TIMED/SABER zonal flux of nitric oxide (NO) infrared cooling radiation correlates well with auroral heating. A factor of ~5 cooling increase is noted in some storms. The cooling radiation intensifies in the auroral zone and spreads towards the equator. Effects of the storm appear at lower latitudes ~18.6 h later. The column density ratio Σ[O/N2] is analyzed based on TIMED/GUVI measurements. Both increases (at low latitudes) and decreases (from auroral to middle latitudes) in the ratio occurs during the geomagnetic storms. We suggest that the column density ratio could be enhanced at low to middle latitudes on the dayside partially due to the superfountain effect (atomic oxygen uplift due to ion-neutral drag). It is suggested that decreases in the Σ[O/N2] ratio at high to middle-latitudes may be caused by high thermospheric temperatures. During SI+s, there is an increase in Σ[O/N2] ratio at auroral latitudes.

  20. Field trial of efficacy of the Leish-tec® vaccine against canine leishmaniasis caused by Leishmania infantum in an endemic area with high transmission rates

    PubMed Central

    Teva, Antonio; dos-Santos, Claudiney B.; Santos, Fernanda Nunes; Pinto, Israel de-Souza; Fux, Blima; Leite, Gustavo Rocha; Falqueto, Aloísio

    2017-01-01

    Background Because domestic dogs are reservoir hosts for visceral leishmaniasis (VL) in Brazil, one of the approaches used to reduce human disease incidence is to cull infected dogs. However, the results of controlled intervention trials based on serological screening of dogs and killing of seropositive animals are equivocal. A prophylactic vaccine to protect dogs from being infectious to the sand fly vector could be an effective strategy to provide sustained control. Here, we investigated whether a currently licensed commercial subunit rA2 protein–saponin vaccine (Leish-tec®) had an additional effect to dog culling on reducing the canine infectious populations. Methodology/Principal findings This prospective study was conducted in an L. infantum highly endemic area of southeast Brazil. At the onset of the intervention, all of the eligible dogs received through subcutaneous route a three-dose vaccine course at 21-day intervals and a booster on month 12. For the purpose of comparison, newly recruited healthy dogs were included as the exposed control group. To ascertain vaccine-induced protection, dogs were screened on clinical and serological criteria every 6 months for a 2-year follow-up period. Antibody-based tests and histopathological examination of post-mortem tissue specimens from euthanized animals were used as a marker of infection. The standardized vaccine regime, apart from being safe, was immunogenic as immunized animals responded with a pronounced production of anti-A2-specific IgG antibodies. It should be noted the mean seroconversion time for infection obtained among immunized exposed dogs (~ 18 months), which was twice as high as that for unvaccinated ones (~ 9 months). After two transmission cycles completed, the cumulative incidence of infection did differ significantly (P = 0.016) between the vaccinated (27%) and unvaccinated (42%) dogs. However, the expected efficacy for the vaccine in inducing clinical protection was not evident since 43% of

  1. Mathematical modelling of ionospheric TEC from Turkish permanent GNSS Network (TPGN) observables during 2009-2017 and predictability of NeQuick and Kriging models

    NASA Astrophysics Data System (ADS)

    Ansari, Kutubuddin; Panda, Sampad Kumar; Corumluoglu, Ozsen

    2018-03-01

    The present study examines the ionospheric Total Electron Content (TEC) variations in the lower mid-latitude Turkish region from the Turkish permanent GNSS network (TPGN) and International GNSS Services (IGS) observations during the years 2009 to 2017. The corresponding vertical TEC (VTEC) predicted by Kriging and NeQuick-2 models are evaluated to realize their efficacy over the country. We studied the diurnal, seasonal and spatial pattern of VTEC variation and tried to estimate by a new mathematical model using the long term of 9 years VTEC data. The diurnal variation of VTEC demonstrates a normal trend with its gradual enhancement from dawn to attain a peak around 09:00-14.00 UT and reaching the minimum level after 22.00 UT. The seasonal behavior of VTEC indicates a strong semi-annual variation of VTEC with maxima in September equinox followed by March equinox and minima in June solstice followed by December solstice. Also, the spatial variation in VTEC depicts a meaningful longitudinal/latitudinal pattern altering with seasons. It decreases longitudinally from the west to the east during March equinox and June solstice increases with latitude. The comparative analysis among the GNSS-VTEC, Kriging, NeQuick and the proposed mathematical model are evaluated with the help one way ANOVA test. The analysis shows that the null hypothesis of the models during storm and quiet days are accepted and suggesting that all models are statistically significantly equivalent from each other. We believe the outcomes from this study would complement towards a relatively better understanding of the lower mid-latitude VTEC variation over the Turkish region and analogous latitudes over the globe.

  2. Efficient Usage of Dense GNSS Networks in Central Europe for the Visualization and Investigation of Ionospheric TEC Variations.

    PubMed

    Nykiel, Grzegorz; Zanimonskiy, Yevgen M; Yampolski, Yuri M; Figurski, Mariusz

    2017-10-10

    The technique of the orthogonal projection of ionosphere electronic content variations for mapping total electron content (TEC) allows us to visualize ionospheric irregularities. For the reconstruction of global ionospheric characteristics, numerous global navigation satellite system (GNSS) receivers located in different regions of the Earth are used as sensors. We used dense GNSS networks in central Europe to detect and investigate a special type of plasma inhomogeneities, called travelling ionospheric disturbances (TID). Such use of GNSS sensors allows us to reconstruct the main TID parameters, such as spatial dimensions, velocities, and directions of their movement. The paper gives examples of the restoration of dynamic characteristics of ionospheric irregularities for quiet and disturbed geophysical conditions. Special attention is paid to the dynamics of ionospheric disturbances stimulated by the magnetic storms of two St. Patrick's Days (17 March 2013 and 2015). Additional opportunities for the remote sensing of the ionosphere with the use of dense regional networks of GNSS receiving sensors have been noted too.

  3. Efficient Usage of Dense GNSS Networks in Central Europe for the Visualization and Investigation of Ionospheric TEC Variations

    PubMed Central

    Zanimonskiy, Yevgen M.; Yampolski, Yuri M.; Figurski, Mariusz

    2017-01-01

    The technique of the orthogonal projection of ionosphere electronic content variations for mapping total electron content (TEC) allows us to visualize ionospheric irregularities. For the reconstruction of global ionospheric characteristics, numerous global navigation satellite system (GNSS) receivers located in different regions of the Earth are used as sensors. We used dense GNSS networks in central Europe to detect and investigate a special type of plasma inhomogeneities, called travelling ionospheric disturbances (TID). Such use of GNSS sensors allows us to reconstruct the main TID parameters, such as spatial dimensions, velocities, and directions of their movement. The paper gives examples of the restoration of dynamic characteristics of ionospheric irregularities for quiet and disturbed geophysical conditions. Special attention is paid to the dynamics of ionospheric disturbances stimulated by the magnetic storms of two St. Patrick’s Days (17 March 2013 and 2015). Additional opportunities for the remote sensing of the ionosphere with the use of dense regional networks of GNSS receiving sensors have been noted too. PMID:28994718

  4. Deterministic prediction of post-sunset ESF based on the strength and asymmetry of EIA from ground based TEC measurements: Preliminary results

    NASA Astrophysics Data System (ADS)

    Thampi, Smitha V.; Ravindran, Sudha; Pant, Tarun Kumar; Devasia, C. V.; Sreelatha, P.; Sridharan, R.

    2006-07-01

    This paper provides the first observations of EIA asymmetry by receiving beacon transmissions onboard low earth orbiting satellites from a single station ground-based receiver. The EIA strength and asymmetry are derived from the latitudinal profiles of TEC obtained from a radio beacon receiver at Trivandrum (8.5°N, 77°E, diplat ~0.5°N). These two parameters, obtained well ahead of the onset time of ESF, are shown to have a definite role on the subsequent ESF activity. In the present paper, both these factors are combined to define a new `threshold parameter' for the generation of ESF. It has been shown that this parameter can define the state of the `background ionosphere' conducive for the generation of ESF irregularities much prior to its onset.

  5. Low latitude ionospheric TEC responses to dynamical complexity quantifiers during transient events over Nigeria

    NASA Astrophysics Data System (ADS)

    Ogunsua, Babalola

    2018-04-01

    In this study, the values of chaoticity and dynamical complexity parameters for some selected storm periods in the year 2011 and 2012 have been computed. This was done using detrended TEC data sets measured from Birnin-Kebbi, Torro and Enugu global positioning system (GPS) receiver stations in Nigeria. It was observed that the significance of difference (SD) values were mostly greater than 1.96 but surprisingly lower than 1.96 in September 29, 2011. The values of the computed SD were also found to be reduced in most cases just after the geomagnetic storm with immediate recovery a day after the main phase of the storm while the values of Lyapunov exponent and Tsallis entropy remains reduced due to the influence of geomagnetic storms. It was also observed that the value of Lyapunov exponent and Tsallis entropy reveals similar variation pattern during storm period in most cases. Also recorded surprisingly were lower values of these dynamical quantifiers during the solar flare event of August 8th and 9th of the year 2011. The possible mechanisms responsible for these observations were further discussed in this work. However, our observations show that the ionospheric effects of some other possible transient events other than geomagnetic storms can also be revealed by the variation of chaoticity and dynamical complexity.

  6. Variability of ionospheric TEC during solar and geomagnetic minima (2008 and 2009): external high speed stream drivers

    NASA Astrophysics Data System (ADS)

    Verkhoglyadova, O. P.; Tsurutani, B. T.; Mannucci, A. J.; Mlynczak, M. G.; Hunt, L. A.; Runge, T.

    2013-02-01

    We study solar wind-ionosphere coupling through the late declining phase/solar minimum and geomagnetic minimum phases during the last solar cycle (SC23) - 2008 and 2009. This interval was characterized by sequences of high-speed solar wind streams (HSSs). The concomitant geomagnetic response was moderate geomagnetic storms and high-intensity, long-duration continuous auroral activity (HILDCAA) events. The JPL Global Ionospheric Map (GIM) software and the GPS total electron content (TEC) database were used to calculate the vertical TEC (VTEC) and estimate daily averaged values in separate latitude and local time ranges. Our results show distinct low- and mid-latitude VTEC responses to HSSs during this interval, with the low-latitude daytime daily averaged values increasing by up to 33 TECU (annual average of ~20 TECU) near local noon (12:00 to 14:00 LT) in 2008. In 2009 during the minimum geomagnetic activity (MGA) interval, the response to HSSs was a maximum of ~30 TECU increases with a slightly lower average value than in 2008. There was a weak nighttime ionospheric response to the HSSs. A well-studied solar cycle declining phase interval, 10-22 October 2003, was analyzed for comparative purposes, with daytime low-latitude VTEC peak values of up to ~58 TECU (event average of ~55 TECU). The ionospheric VTEC changes during 2008-2009 were similar but ~60% less intense on average. There is an evidence of correlations of filtered daily averaged VTEC data with Ap index and solar wind speed. We use the infrared NO and CO2 emission data obtained with SABER on TIMED as a proxy for the radiation balance of the thermosphere. It is shown that infrared emissions increase during HSS events possibly due to increased energy input into the auroral region associated with HILDCAAs. The 2008-2009 HSS intervals were ~85% less intense than the 2003 early declining phase event, with annual averages of daily infrared NO emission power of ~ 3.3 × 1010 W and 2.7 × 1010 W in 2008 and 2009

  7. Using GPS TEC measurements to probe ionospheric spatial spectra at mid-latitudes

    NASA Astrophysics Data System (ADS)

    Lay, E. H.; Parker, P. A.; Light, M. E.; Carrano, C. S.; Debchoudhury, S.; Haaser, R. A.

    2017-12-01

    The physics of how random ionospheric structure causes signal degradation is well understood as weak forward scattering through an effective diffraction grating created by plasma irregularities in the ionosphere. However, the spatial scale spectrum of those irregularities required for input into scintillation models and models of traveling ionospheric disturbances is poorly characterized, particularly at the kilometer to tens of kilometer scale lengths important for very-high-frequency (VHF) scintillation prediction. Furthermore, the majority of characterization studies have been performed in low-latitude or high-latitude regions where geomagnetic activity dominates the physical processes. At mid-latitudes, tropospheric and geomagnetic phenomena compete in disturbing the ionosphere, and it is not well understood how these multiple sources affect the drivers that influence the spatial spectrum. In this study, we are interested in mid-latitude electron density irregularities on the order of 10s of kilometers that would affect VHF signals. Data from the GPS networks Japan GEONET and the Plate Boundary Observatory (PBO, UNAVCO) in the western United States were analyzed for this study. Japan GEONET is a dense network of GPS receivers (station spacing of tens of km), with fairly evenly spaced positions over all of Japan. The PBO, on the other hand, has several pockets of extremely dense coverage (station spacing within a few km), but is less dense on average. We analyze a day with a large solar storm (2015/03/17, St. Patrick's Day Storm) to allow high scintillation potential at mid-latitudes, a day with low geomagnetic activity and low thunderstorm activity (2016/01/31), and a day with low geomagnetic activity and high thunderstorm activity (2015/08/02). We then perform two-dimensional spatial analyses on the TEC data from these two networks on scale lengths of 20 to 200 km to infer the spatial scale spectra.

  8. The impact of the 17 March 2015- St. Patrick's Day storm on the evolutionary pattern of Equatorial Ionization Anomaly over the Indian longitudes using high resolution spatio-temporal TEC maps - New insights

    NASA Astrophysics Data System (ADS)

    Yadav, S.; Sunda, S.; Sridharan, R.

    2016-12-01

    The impact of the St. Patrick's Day storm (17 March 2015) on the major equatorial electro-dynamical process viz., the Equatorial Ionization Anomaly (EIA) has been assessed using 2D (lat. x long.) total electron content (TEC) maps generated from the ground based SBAS (Satellite Based Augmentation System) enabled receiver data. The various aspects of EIA viz., i) evolution/devolution, ii) longitudinal structure, and iii) its variability during different phases of a geomagnetic storm have been brought out. These 2D TEC maps, which have a large latitudinal (5̊ S-45° N) and longitudinal (55-110° E) coverage, show the complete reversal in the longitudinal structure of EIA during the recovery phase of the storm as compared to the quiet day. These results have been explained in the light of the combined effects of the storm associated processes viz., i) the penetration electric fields of magnetosphere origin, ii) storm induced thermospheric winds, and iii) activation of the consequent disturbance dynamo, effectively distorting the longitudinal wave number 4 (WN4) structure of the EIA. It has been shown unambiguously that even a separation of few degrees in longitude ( 30̊) could experience significantly different forcings. The relevance and the far reaching consequences of the study in the light of the current trends and requirements for reliable satellite based navigation are highlighted.

  9. Observing the Birth and evolution of Galaxies - the ATCA-AKARI-ASTE/AzTEC deep South Ecliptic Pole Field

    NASA Astrophysics Data System (ADS)

    White, Glenn; Kohno, Kotaro; Matsuhara, Hideo; Matsuura, Shuji; Hanami, Hitoshi; Lee, Hyung Mok; Pearson, Chris; Takagi, Toshi; Serjeant, Stephen; Jeong, Woongseob; Oyabu, Shinki; Shirahata, Mai; Nakanishi, Kouichiro; Figueredo, Elysandra; Etxaluze, Mireya

    2007-04-01

    We propose deep 20 cm observations supporting the AKARI (3-160 micron)/ASTE/AzTEC (1.1 mm) SEP ultra deep ('Oyabu Field') survey of an extremely low cirrus region at the South Ecliptic Pole. Our combined IR/mm/Radio survey addresses the questions: How do protogalaxies and protospheroids form and evolve? How do AGN link with ULIRGs in their birth and evolution? What is the nature of the mm/submm extragalactic source population? We will address these by sampling the star formation history in the early universe to at least z~2. Compared to other Deep Surveys, a) AKARI multi-band IR measurements allow precision photo-z estimates of optically obscured objects, b) our multi-waveband contiguous area will mitigate effects of cosmic variance, c) the low cirrus noise at the SEP (< 0.08 MJy/sr) rivals that of the Lockman Hole "Astronomy's other ultra-deep 'cosmological window'", and d) our coverage of four FIR bands will characterise the far-IR dust emission hump of our starburst galaxies better than SPITZER's two MIPS bands allow. The ATCA data are crucial to galaxy identification, and determining the star formation rates and intrinsic luminosities through this unique Southern cosmological window.

  10. AzTEC Survey of the Central Molecular Zone: Modeling Dust SEDs and N-PDF with Hierarchical Bayesian Analysis

    NASA Astrophysics Data System (ADS)

    Tang, Yuping; Wang, Daniel; Wilson, Grant; Gutermuth, Robert; Heyer, Mark

    2018-01-01

    We present the AzTEC/LMT survey of dust continuum at 1.1mm on the central ˜ 200pc (CMZ) of our Galaxy. A joint SED analysis of all existing dust continuum surveys on the CMZ is performed, from 160µm to 1.1mm. Our analysis follows a MCMC sampling strategy incorporating the knowledge of PSFs in different maps, which provides unprecedented spacial resolution on distributions of dust temperature, column density and emissivity index. The dense clumps in the CMZ typically show low dust temperature ( 20K), with no significant sign of buried star formation, and a weak evolution of higher emissivity index toward dense peak. A new model is proposed, allowing for varying dust temperature inside a cloud and self-shielding of dust emission, which leads to similar conclusions on dust temperature and grain properties. We further apply a hierarchical Bayesian analysis to infer the column density probability distribution function (N-PDF), while simultaneously removing the Galactic foreground and background emission. The N-PDF shows a steep power-law profile with α > 3, indicating that formation of dense structures are suppressed.

  11. Deep 1.1mm-wavelength imaging of the GOODS-S field by AzTEC/ASTE - I. Source catalogue and number counts

    NASA Astrophysics Data System (ADS)

    Scott, K. S.; Yun, M. S.; Wilson, G. W.; Austermann, J. E.; Aguilar, E.; Aretxaga, I.; Ezawa, H.; Ferrusca, D.; Hatsukade, B.; Hughes, D. H.; Iono, D.; Giavalisco, M.; Kawabe, R.; Kohno, K.; Mauskopf, P. D.; Oshima, T.; Perera, T. A.; Rand, J.; Tamura, Y.; Tosaki, T.; Velazquez, M.; Williams, C. C.; Zeballos, M.

    2010-07-01

    We present the first results from a confusion-limited map of the Great Observatories Origins Deep Survey-South (GOODS-S) taken with the AzTEC camera on the Atacama Submillimeter Telescope Experiment. We imaged a field to a 1σ depth of 0.48-0.73 mJybeam-1, making this one of the deepest blank-field surveys at mm-wavelengths ever achieved. Although by traditional standards our GOODS-S map is extremely confused due to a sea of faint underlying sources, we demonstrate through simulations that our source identification and number counts analyses are robust, and the techniques discussed in this paper are relevant for other deeply confused surveys. We find a total of 41 dusty starburst galaxies with signal-to-noise ratios S/N >= 3. 5 within this uniformly covered region, where only two are expected to be false detections, and an additional seven robust source candidates located in the noisier (1σ ~ 1 mJybeam-1) outer region of the map. We derive the 1.1 mm number counts from this field using two different methods: a fluctuation or ``P(d)'' analysis and a semi-Bayesian technique and find that both methods give consistent results. Our data are well fit by a Schechter function model with . Given the depth of this survey, we put the first tight constraints on the 1.1 mm number counts at S1.1mm = 0.5 mJy, and we find evidence that the faint end of the number counts at from various SCUBA surveys towards lensing clusters are biased high. In contrast to the 870μm survey of this field with the LABOCA camera, we find no apparent underdensity of sources compared to previous surveys at 1.1mm the estimates of the number counts of SMGs at flux densities >1mJy determined here are consistent with those measured from the AzTEC/SHADES survey. Additionally, we find a significant number of SMGs not identified in the LABOCA catalogue. We find that in contrast to observations at λ <= 500μm, MIPS 24μm sources do not resolve the total energy density in the cosmic infrared background at 1

  12. Seismo-Ionospheric Coupling as Intensified EIA Observed by Satellite Electron Density and GPS-TEC Data

    NASA Astrophysics Data System (ADS)

    Ryu, K.; Jangsoo, C.; Kim, S. G.; Jeong, K. S.; Parrot, M.; Pulinets, S. A.; Oyama, K. I.

    2014-12-01

    Examples of intensified EIA features temporally and spatially related to large earthquakes observed by satellites and GPS-TEC are introduced. The precursory, concurrent, and ex-post enhancements of EIA represented by the equatorial electron density, which are thought to be related to the M8.7 Northern Sumatra earthquake of March 2005, the M8.0 Pisco earthquake of August 2007, and the M7.9 Wenchuan Earthquake of 12 May 2008, are shown with space weather condition. Based on the case studies, statistical analysis on the ionospheric electron density data measured by the Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions satellite (DEMETER) over a period of 2005-2010 was executed in order to investigate the correlation between seismic activity and equatorial plasma density variations. To simplify the analysis, three equatorial regions with frequent earthquakes were selected and then one-dimensional time series analysis between the daily seismic activity indices and the EIA intensity indices were performed for each region with excluding the possible effects from the geomagnetic and solar activity. The statistically significant values of the lagged cross-correlation function, particularly in the region with minimal effects of longitudinal asymmetry, indicate that some of the very large earthquakes with M > 7.0 in the low latitude region can accompany observable seismo-ionospheric coupling phenomena in the form of EIA enhancements, even though the seismic activity is not the most significant driver of the equatorial ionospheric evolution. The physical mechanisms of the seismo-ionospheric coupling to explain the observation and the possibility of earthquake prediction using the EIA intensity variation are discussed.

  13. Research on global plasmaspheric electron content by using LEO occultation and GPS data

    NASA Astrophysics Data System (ADS)

    Chen, Peng; Yao, Yibin

    2015-05-01

    This paper investigates the characteristics of global plasmaspheric electron content (pTEC) using COSMIC (Constellation Observing System for Meteorology, Ionosphere and Climate) occultation and GPS (Global Positioning System) data. The ionospheric electron content (iTEC) within 100-1000 km was obtained by fitting the COSMIC occultation electron density profiles, and the pTEC was obtained by subtracting the iTEC from CODE (Center for Orbit Determination in Europe) GIM (global ionosphere maps) TEC provided by University of Bern. This paper also investigates the characteristics of pTEC variations with local time, latitude and season. The results show that in 2011, the worldwide average of pTEC was 4.02 TECu, which is consistent with the findings of other studies. The pTEC shows significant diurnal variation characteristics, that is, pTEC is higher during daytime than during nighttime, but the percentage contribution of pTEC to GPS TEC is higher during nighttime than during daytime. The pTEC varies with the seasons, pTEC hemispheres symmetrically during spring and autumn, while pTEC in the summer hemisphere is higher than that in the winter hemisphere. Moreover, the percentage contribution of pTEC to GPS TEC (total electron content) is higher in winter hemisphere than in summer hemisphere.

  14. AzTEC Millimetre Survey of the COSMOS field - II. Source count overdensity and correlations with large-scale structure

    NASA Astrophysics Data System (ADS)

    Austermann, J. E.; Aretxaga, I.; Hughes, D. H.; Kang, Y.; Kim, S.; Lowenthal, J. D.; Perera, T. A.; Sanders, D. B.; Scott, K. S.; Scoville, N.; Wilson, G. W.; Yun, M. S.

    2009-03-01

    We report an overdensity of bright submillimetre galaxies (SMGs) in the 0.15 deg2 AzTEC/COSMOS survey and a spatial correlation between the SMGs and the optical-IR galaxy density at z <~ 1.1. This portion of the COSMOS field shows a ~3σ overdensity of robust SMG detections when compared to a background, or `blank-field', population model that is consistent with SMG surveys of fields with no extragalactic bias. The SMG overdensity is most significant in the number of very bright detections (14 sources with measured fluxes S1.1mm > 6 mJy), which is entirely incompatible with sample variance within our adopted blank-field number densities and infers an overdensity significance of >> 4σ. We find that the overdensity and spatial correlation to optical-IR galaxy density are most consistent with lensing of a background SMG population by foreground mass structures along the line of sight, rather than physical association of the SMGs with the z <~ 1.1 galaxies/clusters. The SMG positions are only weakly correlated with weak-lensing maps, suggesting that the dominant sources of correlation are individual galaxies and the more tenuous structures in the survey region, and not the massive and compact clusters. These results highlight the important roles cosmic variance and large-scale structure can play in the study of SMGs.

  15. Solar and lunar tidal variabilities in GPS-TEC and geomagnetic field variations: Seasonal as well as during the sudden stratospheric warming of 2010

    NASA Astrophysics Data System (ADS)

    Sridharan, S.

    2017-04-01

    The Global Positioning System (GPS) deduced total electron content (TEC) data at 15°N (geomagnetic), which is the northern crest region of equatorial ionization anomaly, are used to study solar and lunar tidal variabilities during the years 2008 and 2009 and also during the 2009-2010 winter, when a major sudden stratospheric warming (SSW) event has occurred. The diurnal and semidiurnal tidal amplitudes show semiannual variation with maximum amplitudes during February-March and September-November, whereas terdiurnal tide is larger during April-September. They show significant longitudinal variability with larger (smaller) amplitudes over 250°E-150°E (200°E-250°E). Lunar semidiurnal tidal amplitudes show sporadic enhancements during northern winter months and negligible amplitudes during northern summer months. They also show notable longitudinal variabilities. The solar migrating tides DW1 and SW2 show semiannual variation with larger amplitudes during spring equinox months, whereas TW3 maximizes during northern summer. DW2 shows larger amplitudes during summer months. During the SSW, except TW3, the migrating tides DW1 and SW2 show considerable enhancements. Among solar nonmigrating tides, SW1, TW2, and DS0 show larger enhancements. Solar tides in TEC and equatorial electrojet strength over Tirunelveli vary with the time scale of 60 days during October 2009-March 2010 similar to ozone mass mixing ratio at 10 hPa, and this confirms the vital role of ozone in tidal variabilities in ionospheric parameters. Lunar tidal amplitudes in changes in horizontal component of geomagnetic field (ΔH) are larger over Tirunelveli, a station near dip equator. Solar semidiurnal tides in ΔH have larger amplitudes than lunar tides over polar stations, Mawson and Godhavn.Plain Language SummaryIn this paper, the variations of solar and lunar tides in a few ionospheric parameters during the years 2008 and 2009 and during a disturbed</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4986530','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4986530"><span>Identification of embryonic precursor cells that differentiate into thymic epithelial cells expressing autoimmune regulator</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Takizawa, Nobukazu; Miyauchi, Maki; Yanai, Hiromi; Tateishi, Ryosuke; Shinzawa, Miho; Yoshinaga, Riko; Kurihara, Masaaki; Yasuda, Hisataka; Sakamoto, Reiko; Yoshida, Nobuaki</p> <p>2016-01-01</p> <p>Medullary thymic epithelial cells (m<span class="hlt">TECs</span>) expressing autoimmune regulator (Aire) are critical for preventing the onset of autoimmunity. However, the differentiation program of Aire-expressing m<span class="hlt">TECs</span> (Aire+ m<span class="hlt">TECs</span>) is unclear. Here, we describe novel embryonic precursors of Aire+ m<span class="hlt">TECs</span>. We found the candidate precursors of Aire+ m<span class="hlt">TECs</span> (pMECs) by monitoring the expression of receptor activator of nuclear factor-κB (RANK), which is required for Aire+ m<span class="hlt">TEC</span> differentiation. pMECs unexpectedly expressed cortical <span class="hlt">TEC</span> molecules in addition to the m<span class="hlt">TEC</span> markers UEA-1 ligand and RANK and differentiated into m<span class="hlt">TECs</span> in reaggregation thymic organ culture. Introduction of pMECs in the embryonic thymus permitted long-term maintenance of Aire+ m<span class="hlt">TECs</span> and efficiently suppressed the onset of autoimmunity induced by Aire+ m<span class="hlt">TEC</span> deficiency. Mechanistically, pMECs differentiated into Aire+ m<span class="hlt">TECs</span> by tumor necrosis factor receptor-associated factor 6-dependent RANK signaling. Moreover, nonclassical nuclear factor-κB activation triggered by RANK and lymphotoxin-β receptor signaling promoted pMEC induction from progenitors exhibiting lower RANK expression and higher CD24 expression. Thus, our findings identified two novel stages in the differentiation program of Aire+ m<span class="hlt">TECs</span>. PMID:27401343</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AIPC.1279..324H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AIPC.1279..324H"><span>Az<span class="hlt">TEC</span>/ASTE 1.1 mm Deep Surveys: Number Counts and Clustering of Millimeter-bright Galaxies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hatsukade, B.; Kohno, K.; Aretxaga, I.; Austermann, J. E.; Ezawa, H.; Hughes, D. H.; Ikarashi, S.; Iono, D.; Kawabe, R.; Matsuo, H.; Matsuura, S.; Nakanishi, K.; Oshima, T.; Perera, T.; Scott, K. S.; Shirahata, M.; Takeuchi, T. T.; Tamura, Y.; Tanaka, K.; Tosaki, T.; Wilson, G. W.; Yun, M. S.</p> <p>2010-10-01</p> <p>We present number counts and clustering properties of millimeter-bright galaxies uncovered by the Az<span class="hlt">TEC</span> camera mounted on the Atacama Submillimeter Telescope Experiment (ASTE). We surveyed the AKARI Deep Field South (ADF-S), the Subaru/XMM Newton Deep Field (SXDF), and the SSA22 fields with an area of ~0.25 deg2 each with an rms noise level of ~0.4-1.0 mJy. We constructed differential and cumulative number counts, which provide currently the tightest constraints on the faint end. The integration of the best-fit number counts in the ADF-S find that the contribution of 1.1 mm sources with fluxes >=1 mJy to the cosmic infrared background (CIB) at 1.1 mm is 12-16%, suggesting that the large fraction of the CIB originates from faint sources of which the number counts are not yet constrained. We estimate the cosmic star-formation rate density contributed by 1.1 mm sources with >=1 mJy using the best-fit number counts in the ADF-S and find that it is lower by about a factor of 5-10 compared to those derived from UV/optically-selected galaxies at z~2-3. The average mass of dark halos hosting bright 1.1 mm sources was calculated to be 1013-1014 Msolar. Comparison of correlation lengths of 1.1 mm sources with other populations and with a bias evolution model suggests that dark halos hosting bright 1.1 mm sources evolve into systems of clusters at present universe and the 1.1 mm sources residing the dark halos evolve into massive elliptical galaxies located in the center of clusters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19..650M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19..650M"><span>Validation of the technique for absolute total electron content and differential code biases estimation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mylnikova, Anna; Yasyukevich, Yury; Yasyukevich, Anna</p> <p>2017-04-01</p> <p>We have developed a technique for vertical total electron content (<span class="hlt">TEC</span>) and differential code biases (DCBs) estimation using data from a single GPS/GLONASS station. The algorithm is based on <span class="hlt">TEC</span> expansion into Taylor series in space and time (TayAbs<span class="hlt">TEC</span>). We perform the validation of the technique using Global Ionospheric Maps (GIM) computed by Center for Orbit Determination in Europe (CODE) and Jet Propulsion Laboratory (JPL). We compared differences between absolute vertical <span class="hlt">TEC</span> (VTEC) from GIM and VTEC evaluated by TayAbs<span class="hlt">TEC</span> for 2009 year (solar activity minimum - sunspot number about 0), and for 2014 year (solar activity maximum - sunspot number 110). Since there is difference between VTEC from CODE and VTEC from JPL, we compare TayAbs<span class="hlt">TEC</span> VTEC with both of them. We found that TayAbs<span class="hlt">TEC</span> VTEC is closer to CODE VTEC than to JPL VTEC. The difference between TayAbs<span class="hlt">TEC</span> VTEC and GIM VTEC is more noticeable for solar activity maximum (2014) than for solar activity minimum (2009) for both CODE and JPL. The distribution of VTEC differences is close to Gaussian distribution, so we conclude that results of TayAbs<span class="hlt">TEC</span> are in the agreement with GIM VTEC. We also compared DCBs evaluated by TayAbs<span class="hlt">TEC</span> and DCBs from GIM, computed by CODE. The TayAbs<span class="hlt">TEC</span> DCBs are in good agreement with CODE DCBs for GPS satellites, but differ noticeable for GLONASS. We used DCBs to correct slant <span class="hlt">TEC</span> to find out which DCBs give better results. Slant <span class="hlt">TEC</span> correction with CODE DCBs produces negative and nonphysical <span class="hlt">TEC</span> values. Slant <span class="hlt">TEC</span> correction with TayAbs<span class="hlt">TEC</span> DCBs doesn't produce such artifacts. The technique we developed is used for VTEC and DCBs calculation given only local GPS/GLONASS networks data. The evaluated VTEC data are in GIM framework which is handy when various data analyses are made.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17908960','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17908960"><span>The proangiogenic phenotype of tumor-derived endothelial cells is reverted by the overexpression of platelet-activating factor acetylhydrolase.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Doublier, Sophie; Ceretto, Monica; Lupia, Enrico; Bravo, Stefania; Bussolati, Benedetta; Camussi, Giovanni</p> <p>2007-10-01</p> <p>We previously reported that human tumor-derived endothelial cells (<span class="hlt">TEC</span>) have an angiogenic phenotype related to the autocrine production of several angiogenic factors. The purpose of the present study was to evaluate whether an enhanced synthesis of platelet-activating factor (PAF) might contribute to the proangiogenic characteristics of <span class="hlt">TEC</span> and whether its inactivation might inhibit angiogenesis. To address the potential role of PAF in the proangiogenic characteristics of <span class="hlt">TEC</span>, we engineered <span class="hlt">TEC</span> to stably overexpress human plasma PAF-acetylhydrolase (PAF-AH), the major PAF-inactivating enzyme, and we evaluated in vitro and in vivo angiogenesis. <span class="hlt">TECs</span> were able to synthesize a significantly enhanced amount of PAF compared with normal human microvascular endothelial cells when stimulated with thrombin, vascular endothelial growth factor, or soluble CD154. Transfection of <span class="hlt">TEC</span> with PAF-AH (<span class="hlt">TEC</span>-PAF-AH) significantly inhibited apoptosis resistance and spontaneous motility of <span class="hlt">TEC</span>. In addition, PAF and vascular endothelial growth factor stimulation enhanced the motility and adhesion of <span class="hlt">TEC</span> but not of <span class="hlt">TEC</span>-PAF-AH. In vitro, <span class="hlt">TEC</span>-PAF-AH lost the characteristic ability of <span class="hlt">TEC</span> to form vessel-like structures when plated on Matrigel. Finally, when cells were injected s.c. within Matrigel in severe combined immunodeficiency mice or coimplanted with a renal carcinoma cell line, the overexpression of PAF-AH induced a significant reduction of functional vessel formation. These results suggest that inactivation of PAF, produced by <span class="hlt">TEC</span>, by the overexpression of plasma PAF-AH affects survival, migration, and the angiogenic response of <span class="hlt">TEC</span> both in vitro and in vivo.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5825253','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5825253"><span>Targeted deletion of c-Met in thymic epithelial cells leads to an autoimmune phenotype</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Su, Min; Hu, Rong; Song, Yinhong; Liu, Yalan; Lai, Laijun</p> <p>2017-01-01</p> <p>Hepatocyte growth factor (HGF) and its receptor c-Met signaling have been implicated in regulating various types of cells including epithelial cells. We have previously reported that c-Met is expressed by thymic epithelial cells (<span class="hlt">TECs</span>), and that in vivo administration of hybrid cytokines containing IL-7 and the beta- or alpha-chain of HGF significantly increase the number of <span class="hlt">TECs</span>. In order to study the role of c-Met signaling in <span class="hlt">TECs</span>, we generated conditional knockout (cKO) mice in which c-Met was specifically deleted in <span class="hlt">TECs</span> using a Foxn1-Cre transgene. We show here that c-Met deficiency in <span class="hlt">TECs</span> results in age-progressive reduction in <span class="hlt">TEC</span> number and reduced number of regulatory T cells. Consequently, c-Met <span class="hlt">TEC</span> cKO mice displayed an autoimmune phenotype. Thus, c-Met signaling in <span class="hlt">TECs</span> is important for the maintenance of <span class="hlt">TECs</span> and immune self-tolerance. PMID:29363160</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..122.4755F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..122.4755F"><span>Large-scale traveling ionospheric disturbances observed by GPS d<span class="hlt">TEC</span> maps over North and South America on Saint Patrick's Day storm in 2015</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Figueiredo, C. A. O. B.; Wrasse, C. M.; Takahashi, H.; Otsuka, Y.; Shiokawa, K.; Barros, D.</p> <p>2017-04-01</p> <p>Large-scale traveling ionospheric disturbances (LSTIDs) were detected in both Northern and Southern Hemispheres over American sector during the geomagnetic storm on 17-18 March 2015, also known as the Saint Patrick's Day storm. Detrended total electronic content (d<span class="hlt">TEC</span>) maps were made using dense GNSS network receiver data. The retrieved LSTIDs showed wavelengths of 1000 to 2000 km, phase velocity of 300-1000 m/s, and period of 30-50 min. Among them, three couples of LSTIDs were observed propagating from the polar regions to low latitudes. Two wave events observed in daytime showed the propagation direction of southwest in the Northern Hemisphere and northeast in the Southern Hemisphere, which means an asymmetric propagation against the geographic equator. The other wave event observed during the evening hour showed symmetric propagation direction, i.e., southwest in the Northern Hemisphere and northwest in the Southern Hemisphere, whereas their wavelength and phase velocity are significantly different between NH and SH. These observations indicate that the two groups of LSTID have different propagation conditions from polar to low-latitude regions. The observed asymmetric/symmetric propagation forms suggest asymmetric/symmetric auroral current activity between the northern and southern polar regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013yCat..74261845M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013yCat..74261845M"><span>VizieR Online Data Catalog: Az<span class="hlt">TEC</span> survey of the SHADES fields. II. (Michalowski+, 2012)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Michalowski, M. J.; Dunlop, J. S.; Ivison, R. J.; Cirasuolo, M.; Caputi, K. I.; Aretxaga, I.; Arumugam, V.; Austermann, J. E.; Chapin, E. L.; Chapman, S. C.; Coppin, K. E. K.; Egami, E.; Hughes, D. H.; Ibar, E.; Mortier, A. M. J.; Schael, A. M.; Scott, K. S.; Smail, I.; Targett, T. A.; Wagg, J.; Wilson, G. W.; Xu, L.; Yun, M.</p> <p>2013-04-01</p> <p>We utilized the JCMT/Az<span class="hlt">TEC</span> 1.1mm maps and catalogues from Austermann et al. (2010, Cat. J/MNRAS/401/160). These data cover 0.7deg2 to an rms depth of 0.9-1.7mJy/beam. We selected all 148 sources presented by Austermann et al. (2010, Cat. J/MNRAS/401/160) with signal-to-noise ratios (S/Ns) > 3.5, and adopted the statistically deboosted 1.1mm flux densities. The VLA 1.4GHz and GMRT 0.61GHz radio data were taken from Ivison et al. (2005MNRAS.364.1025I, 2007, Cat. J/MNRAS/380/199) and Ibar et al. (2009, Cat. J/MNRAS/397/281, 2010MNRAS.401L..53I), respectively. The mid-IR Spitzer data in the Lockman Hole East field are from programmes PID 81 (PI: G. Rieke) and PID 50249 (PI: E. Egami), described in Egami et al. (2004ApJS..154..130E) and Dye et al. (2008MNRAS.386.1107D), whereas in the UDS field the mid-IR data are from the Spitzer Public Legacy Survey of the UKIDSS UDS (PI: J. Dunlop, http://ssc.spitzer.caltech.edu/spitzermission/observingprograms/ legacy/spuds/) described in Caputi et al. (2011MNRAS.413..162C). The optical data in both fields were obtained with Subaru/SuprimeCam, as described in Dye et al. (2006MNRAS.372.1227D) and Furusawa et al. (2008, Cat. J/ApJS/176/1). The near-IR data in both fields are provided by the UKIRT Infrared Deep Sky Survey (UKIDSS; Lawrence et al. 2007, Cat. II/314) with the SXDF/UDS field benefitting from the ultradeep J, H, K coverage provided by the UDS (e.g. Cirasuolo et al. 2010MNRAS.401.1166C), while the Lockman Hole East field is part of the somewhat shallower UKIDSS DXS (Warren et al., 2007MNRAS.375..213W). (5 data files).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1175972','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/servlets/purl/1175972"><span>Radiation detector system having heat pipe based cooling</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Iwanczyk, Jan S.; Saveliev, Valeri D.; Barkan, Shaul</p> <p>2006-10-31</p> <p>A radiation detector system having a heat pipe based cooling. The radiation detector system includes a radiation detector thermally coupled to a thermo electric cooler (<span class="hlt">TEC</span>). The <span class="hlt">TEC</span> cools down the radiation detector, whereby heat is generated by the <span class="hlt">TEC</span>. A heat removal device dissipates the heat generated by the <span class="hlt">TEC</span> to surrounding environment. A heat pipe has a first end thermally coupled to the <span class="hlt">TEC</span> to receive the heat generated by the <span class="hlt">TEC</span>, and a second end thermally coupled to the heat removal device. The heat pipe transfers the heat generated by the <span class="hlt">TEC</span> from the first end to the second end to be removed by the heat removal device.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AdSpR..60.1777D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AdSpR..60.1777D"><span>Performance evaluation of linear time-series ionospheric Total Electron Content model over low latitude Indian GPS stations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dabbakuti, J. R. K. Kumar; Venkata Ratnam, D.</p> <p>2017-10-01</p> <p>Precise modeling of the ionospheric Total Electron Content (<span class="hlt">TEC</span>) is a critical aspect of Positioning, Navigation, and Timing (PNT) services intended for the Global Navigation Satellite Systems (GNSS) applications as well as Earth Observation System (EOS), satellite communication, and space weather forecasting applications. In this paper, linear time series modeling has been carried out on ionospheric <span class="hlt">TEC</span> at two different locations at Koneru Lakshmaiah University (KLU), Guntur (geographic 16.44° N, 80.62° E; geomagnetic 7.55° N) and Bangalore (geographic 12.97° N, 77.59° E; geomagnetic 4.53° N) at the northern low-latitude region, for the year 2013 in the 24th solar cycle. The impact of the solar and geomagnetic activity on periodic oscillations of <span class="hlt">TEC</span> has been investigated. Results confirm that the correlation coefficient of the estimated <span class="hlt">TEC</span> from the linear model <span class="hlt">TEC</span> and the observed GPS-<span class="hlt">TEC</span> is around 93%. Solar activity is the key component that influences ionospheric daily averaged <span class="hlt">TEC</span> while periodic component reveals the seasonal dependency of <span class="hlt">TEC</span>. Furthermore, it is observed that the influence of geomagnetic activity component on <span class="hlt">TEC</span> is different at both the latitudes. The accuracy of the model has been assessed by comparing the International Reference Ionosphere (IRI) 2012 model <span class="hlt">TEC</span> and <span class="hlt">TEC</span> measurements. Moreover, the absence of winter anomaly is remarkable, as determined by the Root Mean Square Error (RMSE) between the linear model <span class="hlt">TEC</span> and GPS-<span class="hlt">TEC</span>. On the contrary, the IRI2012 model <span class="hlt">TEC</span> evidently failed to predict the absence of winter anomaly in the Equatorial Ionization Anomaly (EIA) crest region. The outcome of this work will be useful for improving the ionospheric now-casting models under various geophysical conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JVGR..325...98L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JVGR..325...98L"><span>Total electron content anomalies associated with global VEI4 + volcanic eruptions during 2002-2015</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Wang; Guo, Jinyun; Yue, Jianping; Shen, Yi; Yang, Yang</p> <p>2016-10-01</p> <p>In previous studies, little attention has been paid to the total electron content (<span class="hlt">TEC</span>) anomalies preceding the volcanic eruption. We analyze the coupling relationship between volcanic eruption and <span class="hlt">TEC</span> anomalies, and discuss the spatial distribution of <span class="hlt">TEC</span> anomalies associated with volcanic geographical location. We utilize the global ionosphere map (GIM) data from the Center for Orbit Determination in Europe (CODE) to analyze <span class="hlt">TEC</span> variations before the global volcanic eruptions indicated by VEI (Volcanic Explosivity Index) 4 + from 2002 to 2015 with the sliding interquartile range method. The results indicate the occurrence rate of <span class="hlt">TEC</span> anomalies before great volcanic eruptions is related with the volcanic type and geographical position. The occurrence rate of <span class="hlt">TEC</span> anomalies before stratovolcano and caldera eruptions is higher than that before shield and pyroclastic shield eruptions, and the occurrence rate of <span class="hlt">TEC</span> anomalies has a descending trend from low latitudes to high latitudes. The <span class="hlt">TEC</span> anomalies before the volcanic eruptions in low-mid latitudes are within the volcanic affected areas, but do not coincide with the volcanic foci. The corresponding <span class="hlt">TEC</span> anomalies could be observed in the conjugated region, and all the <span class="hlt">TEC</span> anomalies in the volcanic affected areas are usually close to bounds of equatorial anomaly zones. However, the <span class="hlt">TEC</span> anomalies preceding these eruptions in high latitudes usually surround the volcano, and no <span class="hlt">TEC</span> anomalies appear in the conjugated region. These conclusions have potential applications to the prediction of great volcanic eruptions in the future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140016568','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140016568"><span>Method of Minimizing Size of Heat Rejection Systems for Thermoelectric Coolers to Cool Detectors in Space</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Choi, Michael K.</p> <p>2014-01-01</p> <p>A thermal design concept of attaching the thermoelectric cooler (<span class="hlt">TEC</span>) hot side directly to the radiator and maximizing the number of <span class="hlt">TECs</span> to cool multiple detectors in space is presented. It minimizes the temperature drop between the <span class="hlt">TECs</span> and radiator. An ethane constant conductance heat pipe transfers heat from the detectors to a <span class="hlt">TEC</span> cold plate which the cold side of the <span class="hlt">TECs</span> is attached to. This thermal design concept minimizes the size of <span class="hlt">TEC</span> heat rejection systems. Hence it reduces the problem of accommodating the radiator within a required envelope. It also reduces the mass of the <span class="hlt">TEC</span> heat rejection system. Thermal testing of a demonstration unit in vacuum verified the thermal performance of the thermal design concept.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4508092','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4508092"><span>Temporal-Spatial Variation of Global GPS-Derived Total Electron Content, 1999–2013</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Guo, Jinyun; Li, Wang; Liu, Xin; Kong, Qiaoli; Zhao, Chunmei; Guo, Bin</p> <p>2015-01-01</p> <p>To investigate the temporal-spatial distribution and evolutions of global Total Electron Content (<span class="hlt">TEC</span>), we estimate the global <span class="hlt">TEC</span> data from 1999 to 2013 by processing the GPS data collected by the International Global Navigation Satellite System (GNSS) Service (IGS) stations, and robustly constructed the <span class="hlt">TEC</span> time series at each of the global 5°×2.5° grids. We found that the spatial distribution of the global <span class="hlt">TEC</span> has a pattern where the number of <span class="hlt">TECs</span> diminishes gradually from a low-latitude region to high-latitude region, and anomalies appear in the equatorial crest and Greenland. Temporal variations show that the peak <span class="hlt">TEC</span> appears in equinoctial months, and this corresponds to the semiannual variation of <span class="hlt">TEC</span>. Furthermore, the winter anomaly is also observed in the equatorial area of the northern hemisphere and high latitudes of the southern hemisphere. Morlet wavelet analysis is used to determine periods of <span class="hlt">TEC</span> variations and results indicate that the 1-day, 26.5-day, semi-annual and annual cycles are the major significant periods. The fitting results of a quadratic polynomial show that the effect of solar activity on <span class="hlt">TEC</span> is stronger in low latitudes than in mid-high latitudes, and stronger in the southern hemisphere than in the northern hemisphere. But the effect in low latitudes in the northern hemisphere is stronger than that in low latitudes in the southern hemisphere. The effect of solar activity on <span class="hlt">TECs</span> was analyzed with the cross wavelet analysis and the wavelet coherence transformation, and we found that there appears to be a strong coherence in the period of about 27 days. So the sunspot as one index of solar activity seriously affects the <span class="hlt">TEC</span> variations with the sun’s rotation. We fit the <span class="hlt">TEC</span> data with the least squares spectral analysis to study the periodic variations of <span class="hlt">TEC</span>. The changing trend of <span class="hlt">TEC</span> is generally -0.08 TECu per year from 1999 to 2013. So <span class="hlt">TECs</span> decrease over most areas year by year, but <span class="hlt">TECs</span> over the Arctic around Greenland</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006cosp...36...93A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006cosp...36...93A"><span>Dynamics of total electron content distribution during strong geomagnetic storms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Astafyeva, E. I.; Afraimovich, E. L.; Kosogorov, E. A.</p> <p></p> <p>We worked out a new method of mapping of total electron content <span class="hlt">TEC</span> equal lines displacement velocity The method is based on the technique of global absolute vertical <span class="hlt">TEC</span> value mapping Global Ionospheric Maps technique GIM GIM with 2-hours time resolution are available from Internet underline ftp cddisa gsfc nasa gov in standard IONEX-files format We determine the displacement velocity absolute value as well as its wave vector orientation from increments of <span class="hlt">TEC</span> x y derivatives and <span class="hlt">TEC</span> time derivative for each standard GIM cell 5 in longitude to 2 5 in latitude Thus we observe global traveling of <span class="hlt">TEC</span> equal lines but we also can estimate the velocity of these line traveling Using the new method we observed anomalous rapid accumulation of the ionosphere plasma at some confined area due to the depletion of the ionization at the other spacious territories During the main phase of the geomagnetic storm on 29-30 October 2003 very large <span class="hlt">TEC</span> enhancements appeared in the southwest of North America <span class="hlt">TEC</span> value in that area reached up to 200 TECU 1 TECU 10 16 m -2 It was found that maximal velocity of <span class="hlt">TEC</span> equal lines motion exceeded 1500 m s and the mean value of the velocity was about 400 m s Azimuth of wave vectors of <span class="hlt">TEC</span> equal lines were orientated toward the center of region with anomaly high values of <span class="hlt">TEC</span> the southwest of North America It should be noted that maximal <span class="hlt">TEC</span> values during geomagnetically quiet conditions is about 60-80 TECU the value of <span class="hlt">TEC</span> equal lines</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29734020','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29734020"><span>Ultrastructural and mechanical changes in tubular epithelial cells by angiotensin II and aldosterone as observed with atomic force microscopy.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Quan, Fu-Shi; Jeong, Kyung Hwan; Lee, Gi-Ja</p> <p>2018-07-01</p> <p>Tubular epithelial cells (<span class="hlt">TECs</span>) play an important pathophysiological role in the promotion of renal fibrosis. Quantitative analysis of the mechanical changes in <span class="hlt">TECs</span> may be helpful in evaluating novel pharmacological strategies. Atomic force microscopy (AFM) is a common nanotechnology tool used for imaging and measuring interaction forces in biological systems. In this study, we used AFM to study ultrastructural and mechanical changes in <span class="hlt">TECs</span> mediated by the renin-angiotensin-aldosterone system. We quantitatively analyzed changes in the mechanical properties of <span class="hlt">TECs</span> using three extrinsic factors, namely, chemical fixation, angiotensin II (AT II), and aldosterone (AD). Fixed <span class="hlt">TECs</span> were 11 times stiffer at the cell body and 3 times stiffer at the cell-cell junction compared to live <span class="hlt">TECs</span>. After stimulation with AT II, live <span class="hlt">TECs</span> were four times stiffer at the junctional area than at the cell body, while fixed <span class="hlt">TECs</span> after AT II stimulation were approximately two times stiffer at the both cell body and cell-cell junction compared to fixed unstimulated <span class="hlt">TECs</span>. Fixed <span class="hlt">TECs</span> also reflected changes in the mechanical properties of <span class="hlt">TECs</span> at the cell body region after AD stimulation. Together, our results suggest that cell stiffness at the cell body region may serve as an effective index for evaluating drugs and stimulation, regardless of whether the cells are live or fixed at the time of analysis. In addition, studying the changes to the intrinsic mechanical property of <span class="hlt">TECs</span> after application of external stimuli may be useful for investigating pathophysiologic mechanisms and effective therapeutic strategies for renal injury. Copyright © 2018 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AIPC.1941b0002A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AIPC.1941b0002A"><span>Method for thermoelectric cooler utilization using manufacturer's technical information</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ajiwiguna, Tri Ayodha; Nugroho, Rio; Ismardi, Abrar</p> <p>2018-03-01</p> <p>Thermoelectric cooler (<span class="hlt">TEC</span>) module has been widely used for many applications. In this study, a procedure to use <span class="hlt">TEC</span> module for specific requirement is developed based on manufacturer's technical data. For study case, the cooling system using <span class="hlt">TEC</span> module is designed and tested to maintain 6.6 liter of water at 24 °C while surrounding temperature is 26 °C. First, cooling load estimation is performed empirically by observing the temperature change when cold water is inside the container. Second, the working temperature on hot side and cold side of <span class="hlt">TEC</span> are determined. Third, the parameters of Seebeck coefficient, thermal resistance and electrical resistance are predicted by using information from the manufacturer. Fourth, the operating current is determined by the assumption the voltage across the <span class="hlt">TEC</span> is 12V. Fifth, cooling capacity of <span class="hlt">TEC</span> module is calculated by using energy balance equation of <span class="hlt">TEC</span>. Sixth, the cooling load and cooling capacity are compared to determine the number of <span class="hlt">TEC</span> module needed. The result of these calculations showed that one <span class="hlt">TEC</span> module is enough for cooling system since the cooling load is 17.5 W while the cooling capacity is 18.87 W. From the experimental result, the set point temperature was achieved using one <span class="hlt">TEC</span> module as predicted in calculations steps.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19820015802','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19820015802"><span>Parametric performance analysis of steam-injected gas turbine with a thermionic-energy-converter-lined combustor</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Choo, Y. K.; Burns, R. K.</p> <p>1982-01-01</p> <p>The performance of steam-injected gas turbines having combustors lined with thermionic energy converters (STIG/<span class="hlt">TEC</span> systems) was analyzed and compared with that of two baseline systems; a steam-injected gas turbine (without a <span class="hlt">TEC</span>-lined combustor) and a conventional combined gas turbine/steam turbine cycle. Common gas turbine parameters were assumed for all of the systems. Two configurations of the STIG/<span class="hlt">TEC</span> system were investigated. In both cases, steam produced in an exhaust-heat-recovery boiler cools the <span class="hlt">TEC</span> collectors. It is then injected into the gas combustion stream and expanded through the gas turbine. The STIG/<span class="hlt">TEC</span> system combines the advantage of gas turbine steam injection with the conversion of high-temperature combustion heat by <span class="hlt">TEC</span>'s. The addition of <span class="hlt">TEC</span>'s to the baseline steam-injected gas turbine improves both its efficiency and specific power. Depending on system configuration and design parameters, the STIG/<span class="hlt">TEC</span> system can also achieve higher efficiency and specific power than the baseline combined cycle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E.761G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E.761G"><span>Clouds and troughs of total electron content detected with the ionospheric weather index</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gulyaeva, Tamara</p> <p>2016-07-01</p> <p>The ionospheric weather W index has been developed with the different thresholds of change in the F2 layer peak electron density NmF2 (proportional to foF2 critical frequency) or total electron content <span class="hlt">TEC</span> relative their quiet reference for quantifying the ionosphere variability. The thresholds of DTEC=log(<span class="hlt">TEC</span>/TECq) are selected for the positive and negative logarithm of <span class="hlt">TEC</span> ratio to the quiet reference median, TECq, at any given location on the Earth. The global W-index maps are produced from Global Ionospheric Maps of Total Electron Content, GIM-<span class="hlt">TEC</span>, and provided online at http://www.izmiran.ru/services/iweather/ and http://www.iololab.org/. Based on W-index maps, Catalogues of the ionospheric storms and sub-storms are produced available for the users. The second generation of the ionospheric weather indices, designated V index, is recently introduced and applied for the retrospective study of GIM-<span class="hlt">TEC</span> variability during 1999-2015. Using sliding-window statistical analysis, moving daily-hourly <span class="hlt">TEC</span> median TECq for 15 preceding days with estimated variance bounds are obtained at cells of GIM-<span class="hlt">TEC</span>. The ionosphere variability index, V, is expressed in terms of Δ<span class="hlt">TEC</span> deviation from the median normalized by the standard deviation STD. V index segmentation is introduced from Vn=-4 in step of 1 to Vp=4 specifying <span class="hlt">TEC</span> storm if an instant <span class="hlt">TEC</span> is outside of TECq+-1STD. The global maps of V index allow distinguish the clouds of enhanced <span class="hlt">TEC</span> (positive storm signatures) and troughs of <span class="hlt">TEC</span> depletion (negative storm signatures) as compared to the background quiet reference TECq map. It is found that the large-scale <span class="hlt">TEC</span> clouds and troughs are observed in space all over the world constituting up to 20-50 percent of cells of GIM-<span class="hlt">TEC</span>. The time variation of these plasma patches is partly following to geomagnetic SSC storm onset. As concerns the interplanetary and the solar wind, SW, sources of the ionospheric storms the <span class="hlt">TEC</span> storms are observed both with IMF and SW precursors and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AdSpR..60.1827B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AdSpR..60.1827B"><span>Salient features of the dayside low latitude ionospheric response to the main phase step-I of the 17 March 2015 geomagnetic storm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bagiya, Mala S.; Sunil, A. S.; Chakrabarty, D.; Sunda, Surendra</p> <p>2017-10-01</p> <p>Based on <span class="hlt">TEC</span> observations by India's GPS Aided GEO Augmented Navigation (GAGAN) GPS network, we report the dayside low latitude ionospheric variations over the Indian region during the moderate main phase step-I of the 17 March 2015 geomagnetic storm. In addition, we assess the efficacy of GPS inferred <span class="hlt">TEC</span> maps by International GNSS service (IGS) in capturing large scale diurnal features of equatorial ionization anomaly (EIA) over the Indian region during this period. Following the prompt penetration electric field (PPE) at ∼0605 UT, equatorial electrojet (EEJ) enhances by ∼55 nT over 75 ± 3oE longitudes where main phase step-I is coincided with local noon. Initial moderate EIA gradually strengthens with the storm commencement. Although GAGAN <span class="hlt">TEC</span> exhibits more intense EIA evolution compare to IGS <span class="hlt">TEC</span> maps, latitudinal extent of EIA are comparable in both. The enhanced EEJ reverses by ∼0918 UT under the effect of overshielding electric field, the later is accompanied by northward turning of interplanetary magnetic field (IMF) Bz. The weakening of well evolved EIA reflects in IGS <span class="hlt">TEC</span> maps after ∼45 min of the overshielding occurrence. In contrary, GAGAN <span class="hlt">TEC</span> shows the corresponding feature after ∼0115 h. Resurgence of EIA, following the PPE ∼1115 UT, shows up in GAGAN <span class="hlt">TEC</span> but IGS <span class="hlt">TEC</span> maps fails in capturing this feature. The observed low latitude <span class="hlt">TEC</span> variations and EIA modulations are explained in terms of the varying storm time disturbance electric fields. The anomalies between the GAGAN <span class="hlt">TEC</span> and IGS <span class="hlt">TEC</span> maps are discussed in terms of the possible limitations of the IGS <span class="hlt">TEC</span> maps in capturing storm time EIA variability over the Indian region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AdSpR..59.1984M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AdSpR..59.1984M"><span>GPS receiver CODE bias estimation: A comparison of two methods</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McCaffrey, Anthony M.; Jayachandran, P. T.; Themens, D. R.; Langley, R. B.</p> <p>2017-04-01</p> <p>The Global Positioning System (GPS) is a valuable tool in the measurement and monitoring of ionospheric total electron content (<span class="hlt">TEC</span>). To obtain accurate GPS-derived <span class="hlt">TEC</span>, satellite and receiver hardware biases, known as differential code biases (DCBs), must be estimated and removed. The Center for Orbit Determination in Europe (CODE) provides monthly averages of receiver DCBs for a significant number of stations in the International Global Navigation Satellite Systems Service (IGS) network. A comparison of the monthly receiver DCBs provided by CODE with DCBs estimated using the minimization of standard deviations (MSD) method on both daily and monthly time intervals, is presented. Calibrated <span class="hlt">TEC</span> obtained using CODE-derived DCBs, is accurate to within 0.74 <span class="hlt">TEC</span> units (TECU) in differenced slant <span class="hlt">TEC</span> (s<span class="hlt">TEC</span>), while calibrated s<span class="hlt">TEC</span> using MSD-derived DCBs results in an accuracy of 1.48 TECU.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002JGRA..107.1127K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002JGRA..107.1127K"><span>Simultaneous total electron content and all-sky camera measurements of an auroral arc</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kintner, P. M.; Kil, H.; Deehr, C.; Schuck, P.</p> <p>2002-07-01</p> <p>We present an example of Global Positioning System (GPS) derived total electron content (<span class="hlt">TEC</span>) and all-sky camera (ASC) images that show increases of <span class="hlt">TEC</span> by ~10 × 1016 electrons m-2 (10 <span class="hlt">TEC</span> units) occurring simultaneously with auroral light in ASC images. The <span class="hlt">TEC</span> example appears to be an E region density enhancement produced by two discrete auroral arcs occurring in the late morning auroral oval at 1000 LT. This suggests that GPS signal <span class="hlt">TEC</span> measurements can be used to detect individual auroral arcs and that individual discrete auroral arcs are responsible for some high-latitude phase scintillations. The specific auroral feature detected was a poleward moving auroral form believed to occur in the polar cap where the ionosphere is convecting antisunward. The magnitude of the rate of change of <span class="hlt">TEC</span> (d<span class="hlt">TEC</span>/dt) is comparable to that previously reported. However, the timescales associated with the event, the order of 1 min, suggest that the data sampling technique commonly used by chain GPS <span class="hlt">TEC</span> receivers (averaging and time decimation) will undersample E region <span class="hlt">TEC</span> perturbations produced by active auroral displays. The localized nature of this example implies that L1 ranging errors of at least 1.6 m will be introduced by auroral arcs into systems relying on differential GPS for navigation or augmentation. Although the <span class="hlt">TEC</span> and auroral arcs presented herein occurred in the late morning auroral oval, we expect that the effects of discrete auroral arcs on GPS <span class="hlt">TEC</span> and subsequent ranging errors should occur at all local times. Furthermore, GPS receivers can be used to detect individual discrete arcs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17878064','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17878064"><span>Performance assessment of the Capilia TB assay and the BD Probe<span class="hlt">Tec</span> ET system for rapid culture confirmation of Mycobacterium tuberculosis.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Jann-Yuan; Lee, Li-Na; Lai, Hsin-Chih; Hsu, Hsiao-Leng; Jan, I-Shiow; Yu, Chong-Jen; Hsueh, Po-Ren; Yang, Pan-Chyr</p> <p>2007-12-01</p> <p>Because of the increasing numbers of nontuberculous mycobacterial isolates from clinical specimens, rapid and accurate methods for culture confirmation of Mycobacterium tuberculosis are urgently needed. The study evaluated the performance of the Capilia TB immunochromatographic assay (TAUNS, Numazu, Japan) for culture confirmation of M. tuberculosis using 242 culture-positive liquid media in 2 mycobacterial laboratories from November 2005 to February 2006. Among the 242 samples, 183 were also tested with the BD Probe<span class="hlt">Tec</span> ET (CTB) assay (Becton Dickinson, Sparks, MD). The results of both assays were compared to the culture results and to each other. The overall sensitivity and specificity of the Capilia TB assay were 98.6% and 97.9%, respectively, and for the CTB assay were 97.3% and 97.1%, respectively. The positive and negative predictive values for the Capilia TB assay were 98.6% and 97.9%, respectively, and for the CTB assay were 98.2% and 95.8%, respectively. Among the 183 samples tested with both assays, 8 had discrepant results, including Capilia-TB-false-positive in 2, CTB-false-positive in another 2, CTB-false-negative in 2, Capilia TB-false-negative in 1, and both assays with false-negative results in the remaining one. This study demonstrated that the Capilia TB assay has a similar diagnostic value with the CTB assay. In addition, with the immunochromatographic method, it is less time-consuming and does not require other laboratory equipment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AnGeo..35..599M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AnGeo..35..599M"><span>Determinations of ionosphere and plasmasphere electron content for an African chain of GPS stations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mazzella, Andrew J., Jr.; Bosco Habarulema, John; Yizengaw, Endawoke</p> <p>2017-05-01</p> <p>The confluence of recent instrumentation deployments in Africa with developments for the determination of plasmasphere electron content using Global Positioning System (GPS) receivers has provided new opportunities for investigations in that region. This investigation, using a selected chain of GPS stations, extends the method (SCORPION) previously applied to a chain of GPS stations in North America in order to separate the ionosphere and plasmasphere contributions to the total electron content (<span class="hlt">TEC</span>) during a day (24 July) in 2011. The results span latitudes from the southern tip of Africa, across the Equator, to the southern Arabian Peninsula, providing a continuous latitudinal profile for both the ionosphere and plasmasphere during this day.The peak diurnal vertical ionosphere electron content (IEC) increases from about 14 <span class="hlt">TEC</span> units (1 <span class="hlt">TEC</span> unit = 1016 electrons m-2) at the southernmost station to about 32 <span class="hlt">TEC</span> units near the geographic equator, then decreases to about 28 <span class="hlt">TEC</span> units at the Arabian Peninsula. The peak diurnal slant plasmasphere electron content (PEC) varies between about 4 and 7 <span class="hlt">TEC</span> units among the stations, with a local latitudinal profile that is significantly influenced by the viewing geometry at the station location, relative to the magnetic field configuration. In contrast, the peak vertical PEC varies between about 1 and 6 <span class="hlt">TEC</span> units among the stations, with a more uniform latitudinal variation.Comparisons to other GPS data analyses are also presented for <span class="hlt">TEC</span>, indicating the influence of the PEC on the determination of latitudinal <span class="hlt">TEC</span> variations and also on the absolute <span class="hlt">TEC</span> levels, by inducing an overestimate of the receiver bias. The derived <span class="hlt">TEC</span> latitudinal profiles, in comparison to global map profiles, tend to differ from the map results only about as much as the map results differ among themselves. A combination of ionosonde IEC and alternative GPS <span class="hlt">TEC</span> measurements, which in principle permits a PEC determination through their difference, was</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19780009913','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19780009913"><span>Optimize out-of-core thermionic energy conversion for nuclear electric propulsion</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Morris, J. F.</p> <p>1977-01-01</p> <p>Current designs for out of core thermionic energy conversion (<span class="hlt">TEC</span>) to power nuclear electric propulsion (NEP) were evaluated. Approaches to improve out of core <span class="hlt">TEC</span> are emphasized and probabilities for success are indicated. <span class="hlt">TEC</span> gains are available with higher emitter temperatures and greater power densities. Good potentialities for accommodating external high temperature, high power density <span class="hlt">TEC</span> with heat pipe cooled reactors exist.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017Cryo...88...81C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017Cryo...88...81C"><span>Evaluation and analysis on the coupling performance of a high-speed turboexpander compressor</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Shuangtao; Fan, Yufeng; Yang, Shanju; Chen, Xingya; Hou, Yu</p> <p>2017-12-01</p> <p>A high-speed turboexpander compressor (<span class="hlt">TEC</span>) for small reverse Brayton air refrigerator is tested and analyzed in the present work. A <span class="hlt">TEC</span> consists of an expander and a compressor, which are coupled together and interact with each other directly. Meanwhile, the expander and compressor have different effects on the refrigerator. The <span class="hlt">TEC</span> overall efficiency, which contains effects of the expander's expansion, the compressor's pre-compression, and the pressure drop between them, was proved. It unifies influences of both compression and expansion processes on the COP of refrigerator and could be used to evaluate the <span class="hlt">TEC</span> overall performance. Then, the coupling parameters were analyzed, which shows that for a <span class="hlt">TEC</span>, the expander efficiency should be fully utilized first, followed by the compressor pressure ratio. Experiments were carried out to test the <span class="hlt">TEC</span> coupling performances. The results indicated that, the <span class="hlt">TEC</span> overall efficiency could reach 67.2%, and meanwhile 22.3% of the energy output was recycled.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20150006003&hterms=foster&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D40%26Ntt%3Dfoster','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20150006003&hterms=foster&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D40%26Ntt%3Dfoster"><span>Observing Tsunamis in the Ionosphere Using Ground Based GPS Measurements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Galvan, D. A.; Komjathy, A.; Song, Y. Tony; Stephens, P.; Hickey, M. P.; Foster, J.</p> <p>2011-01-01</p> <p>Ground-based Global Positioning System (GPS) measurements of ionospheric Total Electron Content (<span class="hlt">TEC</span>) show variations consistent with atmospheric internal gravity waves caused by ocean tsunamis following recent seismic events, including the Tohoku tsunami of March 11, 2011. We observe fluctuations correlated in time, space, and wave properties with this tsunami in <span class="hlt">TEC</span> estimates processed using JPL's Global Ionospheric Mapping Software. These <span class="hlt">TEC</span> estimates were band-pass filtered to remove ionospheric <span class="hlt">TEC</span> variations with periods outside the typical range of internal gravity waves caused by tsunamis. Observable variations in <span class="hlt">TEC</span> appear correlated with the Tohoku tsunami near the epicenter, at Hawaii, and near the west coast of North America. Disturbance magnitudes are 1-10% of the background <span class="hlt">TEC</span> value. Observations near the epicenter are compared to estimates of expected tsunami-driven <span class="hlt">TEC</span> variations produced by Embry Riddle Aeronautical University's Spectral Full Wave Model, an atmosphere-ionosphere coupling model, and found to be in good agreement. The potential exists to apply these detection techniques to real-time GPS <span class="hlt">TEC</span> data, providing estimates of tsunami speed and amplitude that may be useful for future early warning systems.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018RaSc...53..525S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018RaSc...53..525S"><span>Total Electron Content Retrieved From L-Band Radiometers and Potential Improvements to the IGS Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Soldo, Yan; Hong, Liang; El-Nimri, Salem; Le Vine, David M.</p> <p>2018-04-01</p> <p>In recent years, several L-band microwave instruments have been launched into Earth's orbit to measure soil moisture and ocean salinity (e.g., Soil Moisture and Ocean Salinity [SMOS], Aquarius, and Soil Moisture Active/Passive [SMAP]). As the microwave signal travels through the ionosphere, the polarization vector rotates (Faraday rotation) and it is possible to estimate the total electron content (<span class="hlt">TEC</span>) along the path by measuring this change. A comparison is presented of the <span class="hlt">TEC</span> retrieved from Aquarius and SMAP over the ocean with the values provided by the IGS (International Global Navigation Satellite System Service (GNSS)). The <span class="hlt">TEC</span> retrieved from Aquarius and SMAP measurements show good agreement with each other and, on a global scale, are in agreement with the <span class="hlt">TEC</span> provided by the IGS. However, there are cases in which the <span class="hlt">TEC</span> from the two satellite sensors are in good agreement with each other but differ significantly from the IGS <span class="hlt">TEC</span>. The comparison suggests that the L-band instruments are a reliable source of <span class="hlt">TEC</span> over the ocean and could be a valuable supplementary source of <span class="hlt">TEC</span> values that could be assimilated in the IGS models, especially over the ocean, where GNSS ground stations are sparse.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SZF.....1d..47P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SZF.....1d..47P"><span>Ionospheric reaction on sudden stratospheric warming events in Russiás Asia region</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Polyakova, Anna; Perevalova, Natalya; Chernigovskaya, Marina</p> <p>2015-12-01</p> <p>The response of the ionosphere to sudden stratospheric warmings (SSWs) in the Asian region of Russia is studied. Two SSW events observed in 2008-2009 and 2012-2013 winter periods of extreme solar minimum and moderate solar maximum are considered. To detect the ionospheric effects caused by SSWs, we carried out a joint analysis of global ionospheric maps (GIM) of the total electron content (<span class="hlt">TEC</span>), MLS (Microwave Limb Sounder, EOS Aura) measurements of temperature vertical profiles, as well as NCEP/NCAR and UKMO Reanalysis data. For the first time, it was found that during strong SSWs, in the mid-latitude ionosphere the amplitude of diurnal <span class="hlt">TEC</span> variation decreases nearly half compared to quiet days. At the same time, the intensity of <span class="hlt">TEC</span> deviations from the background level increases. It was also found that at SSW peak the midday <span class="hlt">TEC</span> maximum decreases, and night/morning <span class="hlt">TEC</span> values increase compared to quiet days. It was shown that during SSWs, <span class="hlt">TEC</span> dynamics was identical for different geophysical conditions.The response of the ionosphere to sudden stratospheric warmings (SSWs) in the Asian region of Russia is studied. Two SSW events observed in 2008-2009 and 2012-2013 winter periods of extreme solar minimum and moderate solar maximum are considered. To detect the ionospheric effects caused by SSWs, we carried out a joint analysis of global ionospheric maps (GIM) of the total electron content (<span class="hlt">TEC</span>), MLS (Microwave Limb Sounder, EOS Aura) measurements of temperature vertical profiles, as well as NCEP/NCAR and UKMO Reanalysis data. For the first time, it was found that during strong SSWs, in the mid-latitude ionosphere the amplitude of diurnal <span class="hlt">TEC</span> variation decreases nearly half compared to quiet days. At the same time, the intensity of <span class="hlt">TEC</span> deviations from the background level increases. It was also found that at SSW peak the midday <span class="hlt">TEC</span> maximum decreases, and night/morning <span class="hlt">TEC</span> values increase compared to quiet days. It was shown that during SSWs, <span class="hlt">TEC</span> dynamics was</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19880028213&hterms=thermoelectric+coolers&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dthermoelectric%2Bcoolers','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19880028213&hterms=thermoelectric+coolers&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dthermoelectric%2Bcoolers"><span>Generalized approach to cooling charge-coupled devices using thermoelectric coolers</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Petrick, S. Walter</p> <p>1987-01-01</p> <p>This paper is concerned with the use of thermoelectric coolers (<span class="hlt">TECs</span>) to cool charge-coupled devices (CCDs). Heat inputs to the CCD from the warmer environment are identified, and generalized graphs are used to approximate the major heat inputs. A method of choosing and estimating the power consumption of the <span class="hlt">TEC</span> is discussed. This method includes the use of <span class="hlt">TEC</span> performance information supplied by the manufacturer and equations derived from this information. Parameters of the equations are tabulated to enable the reader to use the <span class="hlt">TEC</span> performance equations for choosing and estimating the power needed for specific <span class="hlt">TEC</span> applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSA43A4095I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSA43A4095I"><span>Determination of Ionospheric Total Electron Content Derived from Gnss Measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Inyurt, S.; Mekik, C.; Yildirim, O.</p> <p>2014-12-01</p> <p>Global Navigation Satellite System (GNSS) has been used in numerous fields especially related to satellite- based radio navigation system for a long time. Ionosphere, one of the upper atmosphere layers ranges from 60 km to 1500 km, is a dispersive medium and it includes a number of free electrons and ions. The ionization is mainly subject to the sun and its activity. Ionospheric activity depends also on seasonal, diurnal variations and geographical location. Total Electron Content (<span class="hlt">TEC</span>), which is also called Slant Total Electron Content (STEC), is a parameter that changes according to ionospheric conditions and has highly variable structure. Furthermore, Vertical <span class="hlt">TEC</span> (VTEC) can be explained as <span class="hlt">TEC</span> value in the direction of zenith. Thanks to VTEC, <span class="hlt">TEC</span> values can be modelled. <span class="hlt">TEC</span> is measured in units of TECU and 1TECU= 1016 electrons/m2. Ionospheric modelling has a great importance for improving the accuracies of positioning and understanding the ionosphere. Thus, various models have been developed to detect <span class="hlt">TEC</span> value in the last years. Single Layer Model (SLM) which provides determining <span class="hlt">TEC</span> value and GPS positioning in the ionosphere accurately is one of the most commonly used models. SLM assumes that all free electrons are concentrated in a shell of infinitesimal thickness. In this paper SLM model was used to derive <span class="hlt">TEC</span> values by means of Bernese 5.0 program developed by the University of Bern, Sweden. In this study, we have used regional ionosphere model to derive <span class="hlt">TEC</span> value. First of all, GPS data have been collected from 10 stations in Turkey and 13 IGS stations for 7 days from 06.03.2010 to 12.03.2010. Then, Regional Ionosphere Model (RIM) is created with the reference of the GPS data. At the end of the process, the result files are stored as IONEX format. <span class="hlt">TEC</span> results for those days are obtained with two hours interval. <span class="hlt">TEC</span> variation related to the research area ranges from nearly 6 TECU to approximately 20 TECU. The obtained results show that <span class="hlt">TEC</span> values start</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E.762G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E.762G"><span>Comparison of plasmaspheric electron content over sea and land using Jason-2 observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gulyaeva, Tamara; Cherniak, Iurii; Zakharenkova, Irina</p> <p>2016-07-01</p> <p>The Global Ionospheric Maps of Total Electron Content, GIM-<span class="hlt">TEC</span>, may suffer from model assumptions, in particular, over the oceans where relatively few measurements are available due to a scarcity of ground-based GPS receivers network only on seashores and islands which involve more assumptions or interpolations imposed on GIM mapping techniques. The GPS-derived <span class="hlt">TEC</span> represents the total electron content integrated through the ionosphere, i<span class="hlt">TEC</span>, and the plasmasphere, p<span class="hlt">TEC</span>. The sea/land differences in the F2 layer peak electron density, NmF2, and the peak height, hmF2, gathered with topside sounding data exhibit tilted ionosphere along the seashores with denser electron population at greater peak heights over the sea. Derivation of a sea/land proportion of total electron content from the new source of the satellite-based measurements would allow improve the mapping GIM-<span class="hlt">TEC</span> products and their assimilation by the ionosphere-plasmasphere IRI-Plas model. In this context the data of Jason-2 mission provided through the NOAA CLASS Website (http://www.nsof.class.noaa.gov/saa/products/catSearch) present a unique database of p<span class="hlt">TEC</span> measured through the plasmasphere over the Jason-2 orbit (1335 km) to GPS orbit (20,200 km) which become possible from GPS receivers placed onboard of Jason-2 with a zenith looking antenna that can be used not only for precise orbit determination (POD), but can also provide new data on the plasma density distribution in the plasmasphere. Special interest represents possibility of the potential increase of the data volume in two times due to the successful launch of the Jason-3 mission on 17 January 2016. The present study is focused on a comparison of plasmasphere electron content, p<span class="hlt">TEC</span>, over the sea and land with a unique data base of the plasmasphere electron content, p<span class="hlt">TEC</span>, using measurements onboard Jason-2 satellite during the solar minimum (2009) and solar maximum (2014). Slant <span class="hlt">TEC</span> values were scaled to estimate vertical p<span class="hlt">TEC</span> using a geometric</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM53D2243C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM53D2243C"><span>Real-time Scintillation Monitoring in Alaska from a Longitudinal Chain of ASTRA's SM-211 GPS <span class="hlt">TEC</span> and Scintillation Receivers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crowley, G.; Azeem, S. I.; Reynolds, A.; Santana, J.; Hampton, D. L.</p> <p>2013-12-01</p> <p>Amplitude and phase scintillation can cause serious difficulties for GPS receivers. Intense scintillation can cause loss of lock. High latitude studies generally show that phase scintillation can be severe, but the amplitude scintillation tends to be small. The reason for this is not yet understood. Furthermore, the actual causes of the ionospheric irregularities that produce high latitude scintillation are not well understood. While the gradient drift instability is thought to be important in the F-region, there may be other structures present in either the E- or F-regions. The role of particle precipitation is also not well understood. Four of ASTRA's CASES GPS receivers were deployed in Alaska to demonstrate our ability to map scintillation in realtime, to provide space weather services to GPS users, and to initiate a detailed investigation of these effects. These dual-frequency GPS receivers measure total electron content (<span class="hlt">TEC</span>) and scintillation. The scintillation monitors were deployed in a longitudinal chain at sites in Kaktovic, Fort Yukon, Poker Flat, and Gakona. Scintillation statistics show phase scintillations to be largest at Kaktovic and smallest at Gakona. We present GPS phase scintillation and auroral emission results from the Alaska chain to characterize the correspondence between scintillation and auroral features, and to investigate the role of high latitude auroral features in driving the phase scintillations. We will also present data showing how phase scintillation can cause other GPS receivers to lose lock. The data and results are particularly valuable because they illustrate some of the challenges of using GPS systems for positioning and navigation in an auroral region like Alaska. These challenges for snowplough drivers were recently highlighted, along with the CASES SM-211 space weather monitor, in a special video in which ASTRA and three other small businesses were presented with an entrepreneurial award from William Shatner (http://youtu.be/bIVKEQH_YPk).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AdSpR..55..231C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AdSpR..55..231C"><span>Variations of total electron content in the equatorial anomaly region in Thailand</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chowdhary, V. Rajesh; Tripathi, N. K.; Arunpold, Sanit; Raju, Durairaju Kumaran</p> <p>2015-01-01</p> <p>This paper presents the first results of total electron content (<span class="hlt">TEC</span>), derived by analyzing dual frequency Novatel GSV4004 GPS receiver's data which were installed by the SCINDA project, located at the Asian Institute of Technology, Bangkok (AITB, 14.079N, 100.612E) and Chiang Mai University, Chiang Mai (CHGM, 18.480N, 98.570E) with magnetic latitude of 4.13°N and 8.61°N respectively in Thailand, for the year 2011. These two stations are separated by 657 km in the equatorial anomaly region. The highest <span class="hlt">TEC</span> values occurred from 1500 to 1900 LT throughout the study period. The diurnal, monthly and seasonal GPS-<span class="hlt">TEC</span> have been plotted and analyzed. The diurnal peaks in GPS-<span class="hlt">TEC</span> is observed to be maximum during equinoctial months (March, April, September and October) and minimum in solstice months (January, February, June, July and December). These high <span class="hlt">TEC</span> values have been attributed to the solar extreme ultra-violet ionization coupled with the upward vertical E × B drift. A comparison of both station's <span class="hlt">TEC</span> has been carried out and found that CHGM station experiences higher values of <span class="hlt">TEC</span> than AITB station, due to formation of ionization crest over the CHGM station. Also, <span class="hlt">TEC</span> values have shown increasing trend due to approaching solar maximum. These results from both stations were also compared with the <span class="hlt">TEC</span> derived from the International Reference Ionosphere's (IRI) recently released, IRI-2012 model. Results have shown positive correlation with IRI-2012 model. Although, IRI-model does not show any response to geomagnetic activity, the IRI model normally remains smooth and underestimates <span class="hlt">TEC</span> during a storm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22202477-isolated-tumor-endothelial-cells-maintain-specific-character-during-long-term-culture','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22202477-isolated-tumor-endothelial-cells-maintain-specific-character-during-long-term-culture"><span>Isolated tumor endothelial cells maintain specific character during long-term culture</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Matsuda, Kohei; Oral Pathology and Biology, Hokkaido University Graduate School of Dental Medicine, N13 W7, Kita-ku, Sapporo 060-8586; Oral and Maxillofacial Surgery, Hokkaido University Graduate School of Dental Medicine, N13 W7, Kita-ku, Sapporo 060-8586</p> <p></p> <p>Tumor angiogenesis is necessary for solid tumor progression and metastasis. Increasing evidence indicates that tumor endothelial cells (<span class="hlt">TECs</span>) are more relevant to the study of tumor angiogenesis than normal endothelial cells (NECs) because their morphologies and gene expression are different from NECs. However, it is challenging to isolate and culture large numbers of pure ECs from tumor tissue since the percentage of ECs is only about 1-2% and tumor cells and fibroblasts easily overgrow them. In addition, there has been concern that isolated <span class="hlt">TECs</span> may lose their special phenotype once they are dissociated from tumor cells. In this study, wemore » have successfully purified murine <span class="hlt">TECs</span> from four different human tumor xenografts and NECs from murine dermal tissue. Isolated ECs expressed endothelial markers, such as CD31, VE-cadherin (CD144), and endoglin (CD105), for more than 3 months after isolation. <span class="hlt">TECs</span> maintained tumor endothelial-specific markers, such as tumor endothelial marker 8 (TEM8) and aminopeptidase N (APN), as in tumor blood vessels in vivo. In addition, <span class="hlt">TECs</span> were more proliferative and motile than NECs. <span class="hlt">TECs</span> showed a higher response to VEGF and higher expression of VEGF receptors-1 and -2 than NECs did. Stem cell antigen-1 was up-regulated in all four <span class="hlt">TECs</span>, suggesting that they have a kind of stemness. Cultured <span class="hlt">TECs</span> maintain distinct biological differences from NECs as in vivo. In conclusion, it was suggested that <span class="hlt">TECs</span> are relevant material for tumor angiogenesis research.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5399489','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5399489"><span>Real-Time Detection of Tsunami Ionospheric Disturbances with a Stand-Alone GNSS Receiver: A Preliminary Feasibility Demonstration</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Savastano, Giorgio; Komjathy, Attila; Verkhoglyadova, Olga; Mazzoni, Augusto; Crespi, Mattia; Wei, Yong; Mannucci, Anthony J.</p> <p>2017-01-01</p> <p>It is well known that tsunamis can produce gravity waves that propagate up to the ionosphere generating disturbed electron densities in the E and F regions. These ionospheric disturbances can be studied in detail using ionospheric total electron content (<span class="hlt">TEC</span>) measurements collected by continuously operating ground-based receivers from the Global Navigation Satellite Systems (GNSS). Here, we present results using a new approach, named VARION (Variometric Approach for Real-Time Ionosphere Observation), and estimate slant <span class="hlt">TEC</span> (s<span class="hlt">TEC</span>) variations in a real-time scenario. Using the VARION algorithm we compute <span class="hlt">TEC</span> variations at 56 GPS receivers in Hawaii as induced by the 2012 Haida Gwaii tsunami event. We observe <span class="hlt">TEC</span> perturbations with amplitudes of up to 0.25 <span class="hlt">TEC</span> units and traveling ionospheric perturbations (TIDs) moving away from the earthquake epicenter at an approximate speed of 316 m/s. We perform a wavelet analysis to analyze localized variations of power in the <span class="hlt">TEC</span> time series and we find perturbation periods consistent with a tsunami typical deep ocean period. Finally, we present comparisons with the real-time tsunami MOST (Method of Splitting Tsunami) model produced by the NOAA Center for Tsunami Research and we observe variations in <span class="hlt">TEC</span> that correlate in time and space with the tsunami waves. PMID:28429754</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017NatSR...746607S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017NatSR...746607S"><span>Real-Time Detection of Tsunami Ionospheric Disturbances with a Stand-Alone GNSS Receiver: A Preliminary Feasibility Demonstration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Savastano, Giorgio; Komjathy, Attila; Verkhoglyadova, Olga; Mazzoni, Augusto; Crespi, Mattia; Wei, Yong; Mannucci, Anthony J.</p> <p>2017-04-01</p> <p>It is well known that tsunamis can produce gravity waves that propagate up to the ionosphere generating disturbed electron densities in the E and F regions. These ionospheric disturbances can be studied in detail using ionospheric total electron content (<span class="hlt">TEC</span>) measurements collected by continuously operating ground-based receivers from the Global Navigation Satellite Systems (GNSS). Here, we present results using a new approach, named VARION (Variometric Approach for Real-Time Ionosphere Observation), and estimate slant <span class="hlt">TEC</span> (s<span class="hlt">TEC</span>) variations in a real-time scenario. Using the VARION algorithm we compute <span class="hlt">TEC</span> variations at 56 GPS receivers in Hawaii as induced by the 2012 Haida Gwaii tsunami event. We observe <span class="hlt">TEC</span> perturbations with amplitudes of up to 0.25 <span class="hlt">TEC</span> units and traveling ionospheric perturbations (TIDs) moving away from the earthquake epicenter at an approximate speed of 316 m/s. We perform a wavelet analysis to analyze localized variations of power in the <span class="hlt">TEC</span> time series and we find perturbation periods consistent with a tsunami typical deep ocean period. Finally, we present comparisons with the real-time tsunami MOST (Method of Splitting Tsunami) model produced by the NOAA Center for Tsunami Research and we observe variations in <span class="hlt">TEC</span> that correlate in time and space with the tsunami waves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28429754','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28429754"><span>Real-Time Detection of Tsunami Ionospheric Disturbances with a Stand-Alone GNSS Receiver: A Preliminary Feasibility Demonstration.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Savastano, Giorgio; Komjathy, Attila; Verkhoglyadova, Olga; Mazzoni, Augusto; Crespi, Mattia; Wei, Yong; Mannucci, Anthony J</p> <p>2017-04-21</p> <p>It is well known that tsunamis can produce gravity waves that propagate up to the ionosphere generating disturbed electron densities in the E and F regions. These ionospheric disturbances can be studied in detail using ionospheric total electron content (<span class="hlt">TEC</span>) measurements collected by continuously operating ground-based receivers from the Global Navigation Satellite Systems (GNSS). Here, we present results using a new approach, named VARION (Variometric Approach for Real-Time Ionosphere Observation), and estimate slant <span class="hlt">TEC</span> (s<span class="hlt">TEC</span>) variations in a real-time scenario. Using the VARION algorithm we compute <span class="hlt">TEC</span> variations at 56 GPS receivers in Hawaii as induced by the 2012 Haida Gwaii tsunami event. We observe <span class="hlt">TEC</span> perturbations with amplitudes of up to 0.25 <span class="hlt">TEC</span> units and traveling ionospheric perturbations (TIDs) moving away from the earthquake epicenter at an approximate speed of 316 m/s. We perform a wavelet analysis to analyze localized variations of power in the <span class="hlt">TEC</span> time series and we find perturbation periods consistent with a tsunami typical deep ocean period. Finally, we present comparisons with the real-time tsunami MOST (Method of Splitting Tsunami) model produced by the NOAA Center for Tsunami Research and we observe variations in <span class="hlt">TEC</span> that correlate in time and space with the tsunami waves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E..72A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E..72A"><span>Comparing GNSS Total Electron Content of Sonmiani, Pakistan with NeQuick-2 & IRI-2012 during July 2014 - June 2015</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ayyaz Ameen, Muhammad; Ghafoor, Memoona; Weimin, Zhen</p> <p>2016-07-01</p> <p>Total Electron Content (<span class="hlt">TEC</span>) data acquired by an in-house fabricated GNSS receiver (by China Research Institute of Radiowave Propagation, CRIRP) working with NovaTel antenna installed at Sonmiani (geograph. 24.95°N, 67.14°E) is being reported for the first time. The period under study is one year (July 2014 to June 2015) which is based upon the hourly instantaneous <span class="hlt">TEC</span> values of 120 days (10 international quietest days, IQD per month). The data confirms the annual variation of <span class="hlt">TEC</span> at the station which lies at the northern crest of equatorial ionization anomaly (EIA) region. GNSS <span class="hlt">TEC</span> values in general are then compared with NeQuick-2 and IRI-2012. Model comparison shows that NeQuick-2 predicts the <span class="hlt">TEC</span> with greater confidence whereas IRI-2012 shows larger discrepancies with respect to the data. Seasonal variation shows the highest <span class="hlt">TEC</span> values during equinox months. December solstice values of <span class="hlt">TEC</span> are higher than the June solstice values, this confirms that the seasonal anomaly is dominating in the region during the course of study.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JGRA..123.3217L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JGRA..123.3217L"><span>Was Magnetic Storm the Only Driver of the Long-Duration Enhancements of Daytime Total Electron Content in the Asian-Australian Sector Between 7 and 12 September 2017?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lei, Jiuhou; Huang, Fuqing; Chen, Xuetao; Zhong, Jiahao; Ren, Dexin; Wang, Wenbin; Yue, Xinan; Luan, Xiaoli; Jia, Mingjiao; Dou, Xiankang; Hu, Lianhuan; Ning, Baiqi; Owolabi, Charles; Chen, Jinsong; Li, Guozhu; Xue, Xianghui</p> <p>2018-04-01</p> <p>In this study, multiple data sets from Beidou geostationary orbit satellites total electron contents (<span class="hlt">TECs</span>), ionosonde, meteor radar, magnetometer, and model simulations have been used to investigate the ionospheric responses in the Asian-Australian sector during the September 2017 geomagnetic storm. It was found that long-duration daytime <span class="hlt">TEC</span> enhancements that lasted from 7 to 12 September 2017 were observed by the Beidou geostationary orbit satellite constellation. This is a unique event as the prominent <span class="hlt">TEC</span> enhancements persisted during the storm recovery phase when geomagnetic activity became quiet. The Thermosphere-Ionosphere Electrodynamics Global Circulation Model predicted that the <span class="hlt">TEC</span> enhancements on 7-9 September were associated with the geomagnetic activity, but it showed significant electron density depletions on 10 and 11 September in contrast to the observed <span class="hlt">TEC</span> enhancements. Our results suggested that the observed long-duration <span class="hlt">TEC</span> enhancements from 7 to 12 September are mainly associated with the interplay of ionospheric dynamics and electrodynamics. Nevertheless, the root causes for the observed <span class="hlt">TEC</span> enhancements seen in the storm recovery phase are unknown and require further observations and model studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeoRL..4412041C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeoRL..4412041C"><span>GNSS Observations of Ionospheric Variations During the 21 August 2017 Solar Eclipse</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Coster, Anthea J.; Goncharenko, Larisa; Zhang, Shun-Rong; Erickson, Philip J.; Rideout, William; Vierinen, Juha</p> <p>2017-12-01</p> <p>On 21 August 2017, during daytime hours, a total solar eclipse with a narrow ˜160 km wide umbral shadow occurred across the continental United States. Totality was observed from the Oregon coast at ˜9:15 local standard time (LST) (17:20 UT) to the South Carolina coast at ˜13:27 LST (18:47 UT). A dense network of Global Navigation Satellite Systems (GNSS) receivers was utilized to produce total electron content (<span class="hlt">TEC</span>) and differential <span class="hlt">TEC</span>. These data were analyzed for the latitudinal and longitudinal response of the <span class="hlt">TEC</span> and for the presence of traveling ionospheric disturbances (TIDs) during eclipse passage. A significant <span class="hlt">TEC</span> depletion, in some cases greater than 60%, was observed associated with the eclipse shadow, exceeding initial model predictions of 35%. Evidence of enhanced large-scale TID activity was detected over the United States prior to and following the large <span class="hlt">TEC</span> depletion observed near the time of totality. Signatures of enhanced <span class="hlt">TEC</span> structures were observed over the Rocky Mountain chain during the main period of <span class="hlt">TEC</span> depletion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26441966','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26441966"><span>Positive and Negative Regulatory Mechanisms for Fine-Tuning Cellularity and Functions of Medullary Thymic Epithelial Cells.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Akiyama, Taishin; Tateishi, Ryosuke; Akiyama, Nobuko; Yoshinaga, Riko; Kobayashi, Tetsuya J</p> <p>2015-01-01</p> <p>Self-tolerant T cells and regulatory T cells develop in the thymus. A wide variety of cell-cell interactions in the thymus is required for the differentiation, proliferation, and repertoire selection of T cells. Various secreted and cell surface molecules expressed in thymic epithelial cells (<span class="hlt">TECs</span>) mediate these processes. Moreover, cytokines expressed by cells of hematopoietic origin regulate the cellularity of <span class="hlt">TECs</span>. Tumor necrosis factor (TNF) family RANK ligand, lymphotoxin, and CD40 ligand, expressed in T cells and innate lymphoid cells (ILCs), promote the differentiation and proliferation of medullary <span class="hlt">TECs</span> (m<span class="hlt">TECs</span>) that play critical roles in the induction of immune tolerance. A recent study suggests that interleukin-22 (IL-22) produced by ILCs promotes regeneration of <span class="hlt">TECs</span> after irradiation. Intriguingly, tumor growth factor-β and osteoprotegerin limit cellularity of m<span class="hlt">TECs</span>, thereby attenuating regulatory T cell generation. We will review recent insights into the molecular basis for cell-cell interactions regulating differentiation and proliferation of m<span class="hlt">TECs</span> and also discuss about a perspective on use of mathematical models for understanding this complicated system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018GeoRL..45...31H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018GeoRL..45...31H"><span>Nighttime Medium-Scale Traveling Ionospheric Disturbances From Airglow Imager and Global Navigation Satellite Systems Observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huang, Fuqing; Lei, Jiuhou; Dou, Xiankang; Luan, Xiaoli; Zhong, Jiahao</p> <p>2018-01-01</p> <p>In this study, coordinated airglow imager, GPS total electron content (<span class="hlt">TEC</span>), and Beidou geostationary orbit (GEO) <span class="hlt">TEC</span> observations for the first time are used to investigate the characteristics of nighttime medium-scale traveling ionospheric disturbances (MSTIDs) over central China. The results indicated that the features of nighttime MSTIDs from three types of observations are generally consistent, whereas the nighttime MSTID features from the Beidou GEO <span class="hlt">TEC</span> are in better agreement with those from airglow images as compared with the GPS <span class="hlt">TEC</span>, given that the nighttime MSTID characteristics from GPS <span class="hlt">TEC</span> are significantly affected by Doppler effect due to satellite movement. It is also found that there are three peaks in the seasonal variations of the occurrence rate of nighttime MSTIDs in 2016. Our study revealed that the Beidou GEO satellites provided fidelity <span class="hlt">TEC</span> observations to study the ionospheric variability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AdSpR..60..419V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AdSpR..60..419V"><span>Analysis of ionosphere variability over low-latitude GNSS stations during 24th solar maximum period</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Venkata Ratnam, D.; Sivavaraprasad, G.; Latha Devi, N. S. M. P.</p> <p>2017-07-01</p> <p>Global Positioning System (GPS) is a remote sensing tool of space weather and ionospheric variations. However, the interplanetary space-dependent drifts in the ionospheric irregularities cause predominant ranging errors in the GPS signals. The dynamic variability of the low-latitude ionosphere is an imperative threat to the satellite-based radio communication and navigation ranging systems. The study of temporal and spatial variations in the ionosphere has triggered new investigations in modelling, nowcasting and forecasting the ionospheric variations. Hence, in this paper, the dynamism in the day-to-day, month-to-month and seasonal variability of the ionospheric Total Electron Content (<span class="hlt">TEC</span>) has been explored during the solar maximum period, January-December 2013, of the 24th solar cycle. The spatial and temporal variations of the ionosphere are analysed using the <span class="hlt">TEC</span> values derived from three Indian low-latitude GPS stations, namely, Bengaluru, Guntur and Hyderabad, separated by 13-18° in latitude and 77-81° in longitude. The observed regional GPS-<span class="hlt">TEC</span> variations are compared with the predicted <span class="hlt">TEC</span> values of the International Reference Ionosphere (IRI-2012 and 2007) models. Ionospheric parameters such as Vertical <span class="hlt">TEC</span> (VTEC), relative <span class="hlt">TEC</span> deviation index and monthly variations in the grand-mean of ionosphere <span class="hlt">TEC</span> and <span class="hlt">TEC</span> intensity, along with the upper and lower quartiles, are adopted to investigate the ionosphere <span class="hlt">TEC</span> variability during quiet and disturbed days. The maximum ionospheric <span class="hlt">TEC</span> variability is found during March and September equinoxes, followed by December solstice while the minimum variability is observed during June solstice. IRI models are in reasonable agreement with GPS <span class="hlt">TEC</span> but are overestimating during dawn hours (01:00-06:00 LT) as compared to the dusk hours. Higher percentage deviations are observed during equinoctial months than summer over EIA stations, Guntur and Hyderabad. GPS <span class="hlt">TEC</span> variations are overestimated during dawn hours for all the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.3175B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.3175B"><span>Ionospheric storms—A challenge for empirical forecast of the total electron content</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Borries, C.; Berdermann, J.; Jakowski, N.; Wilken, V.</p> <p>2015-04-01</p> <p>Since the last decades, the functioning of society depends more and more on well-functioning communication and navigation systems. As the availability and reliability of most of these satellite-based systems can be severely impacted by ionospheric storms, the accurate forecast of these events becomes a required task for mitigating social and economic risks. Here we aim to make initial steps toward an empirical model for ionospheric perturbations related to space weather events that are observable in the total electron content (<span class="hlt">TEC</span>). The perturbation <span class="hlt">TEC</span> forecast model will be a fast and robust approach, improving <span class="hlt">TEC</span> forecasts based on climatological models during storm conditions. The derivation of such a model is a challenging task, because although a general dependence of the storm features (enhancement or depletion of electron density) on the storm onset time, local time, season and geomagnetic latitude is well known, there is a large deviation from the mean behavior. For a better understanding of storm conditions, this paper presents analyses of ionospheric storms observed in the <span class="hlt">TEC</span>, broken down into diverse classes of storms. It provides a detailed characterization of the typical ionospheric storm behavior over Europe from high to midlatitudes, beyond case studies. Generally, the typical clear strong <span class="hlt">TEC</span> enhancement starting in high latitudes and propagating equatorward is found to be strongest for storms starting in the morning hours independent of the season. In midlatitudes, it is strongest during noon. In addition, a clear difference between summer and winter storms is reported. While only winter storms develop high-latitude <span class="hlt">TEC</span> enhancements, only summer storms typically exhibit <span class="hlt">TEC</span> depletions during the storm recovery phase. During winter storms <span class="hlt">TEC</span> enhancements can also occur the day following the storm onset, in contrast to summer storms. Strong correlation of <span class="hlt">TEC</span> perturbation amplitudes to the Bz component of the interplanetary magnetic field and to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27905487','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27905487"><span>A possible space-based tsunami early warning system using observations of the tsunami ionospheric hole.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kamogawa, Masashi; Orihara, Yoshiaki; Tsurudome, Chiaki; Tomida, Yuto; Kanaya, Tatsuya; Ikeda, Daiki; Gusman, Aditya Riadi; Kakinami, Yoshihiro; Liu, Jann-Yenq; Toyoda, Atsushi</p> <p>2016-12-01</p> <p>Ionospheric plasma disturbances after a large tsunami can be detected by measurement of the total electron content (<span class="hlt">TEC</span>) between a Global Positioning System (GPS) satellite and its ground-based receivers. <span class="hlt">TEC</span> depression lasting for a few minutes to tens of minutes termed as tsunami ionospheric hole (TIH) is formed above the tsunami source area. Here we describe the quantitative relationship between initial tsunami height and the <span class="hlt">TEC</span> depression rate caused by a TIH from seven tsunamigenic earthquakes in Japan and Chile. We found that the percentage of <span class="hlt">TEC</span> depression and initial tsunami height are correlated and the largest <span class="hlt">TEC</span> depressions appear 10 to 20 minutes after the main shocks. Our findings imply that Ionospheric <span class="hlt">TEC</span> measurement using the existing ground receiver networks could be used in an early warning system for near-field tsunamis that take more than 20 minutes to arrive in coastal areas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5131353','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5131353"><span>A possible space-based tsunami early warning system using observations of the tsunami ionospheric hole</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kamogawa, Masashi; Orihara, Yoshiaki; Tsurudome, Chiaki; Tomida, Yuto; Kanaya, Tatsuya; Ikeda, Daiki; Gusman, Aditya Riadi; Kakinami, Yoshihiro; Liu, Jann-Yenq; Toyoda, Atsushi</p> <p>2016-01-01</p> <p>Ionospheric plasma disturbances after a large tsunami can be detected by measurement of the total electron content (<span class="hlt">TEC</span>) between a Global Positioning System (GPS) satellite and its ground-based receivers. <span class="hlt">TEC</span> depression lasting for a few minutes to tens of minutes termed as tsunami ionospheric hole (TIH) is formed above the tsunami source area. Here we describe the quantitative relationship between initial tsunami height and the <span class="hlt">TEC</span> depression rate caused by a TIH from seven tsunamigenic earthquakes in Japan and Chile. We found that the percentage of <span class="hlt">TEC</span> depression and initial tsunami height are correlated and the largest <span class="hlt">TEC</span> depressions appear 10 to 20 minutes after the main shocks. Our findings imply that Ionospheric <span class="hlt">TEC</span> measurement using the existing ground receiver networks could be used in an early warning system for near-field tsunamis that take more than 20 minutes to arrive in coastal areas. PMID:27905487</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSH51A2436T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSH51A2436T"><span>Characterizing Interplanetary Structures of Long-Lasting Ionospheric Storm Events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tandoi, C.; Dong, Y.; Ngwira, C. M.; Damas, M. C.</p> <p>2015-12-01</p> <p>Geomagnetic storms can result in periods of heightened <span class="hlt">TEC</span> (Total Electron Content) in Earth's ionosphere. These periods of change in <span class="hlt">TEC</span> (d<span class="hlt">TEC</span>) can have adverse impacts on a technological society, such as scintillation of radio signals used by communication and navigation satellites. However, it is unknown which exact properties of a given storm cause d<span class="hlt">TEC</span>. We are comparing different solar wind properties that result in a significant long-lasting d<span class="hlt">TEC</span> to see if there are any patterns that remain constant in these storms. These properties, among others, include the interplanetary magnetic field By and Bz components, the proton density, and the flow speed. As a preliminary investigation, we have studied 15 solar storms. Preliminary results will be presented. In the future, we hope to increase our sample size and analyze over 80 different solar storms, which result in significant d<span class="hlt">TEC</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22910002','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22910002"><span>Purified enzymes improve isolation and characterization of the adult thymic epithelium.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Seach, Natalie; Wong, Kahlia; Hammett, Maree; Boyd, Richard L; Chidgey, Ann P</p> <p>2012-11-30</p> <p>The reproducible isolation and accurate characterization of thymic epithelial cell (<span class="hlt">TEC</span>) subsets is of critical importance to the ongoing study of thymopoiesis and its functional decline with age. The study of adult <span class="hlt">TEC</span>, however, is significantly hampered due to the severely low stromal to hematopoietic cell ratio. Non-biased digestion and enrichment protocols are thus essential to ensure optimal cell yield and accurate representation of stromal subsets, as close as possible to their in vivo representation. Current digestion protocols predominantly involve diverse, relatively impure enzymatic variants of crude collagenase and collagenase/dispase (col/disp) preparations, which have variable efficacy and are often suboptimal in their ability to mediate complete digestion of thymus tissue. To address these issues we compared traditional col/disp preparations with the latest panel of Liberase products that contain a blend of highly purified collagenase and neutral protease enzymes. Liberase enzymes revealed a more rapid, complete dissociation of thymus tissue; minimizing loss of viability and increasing recovery of thymic stromal cell (TSC) elements. In particular, the recovery and viability of <span class="hlt">TEC</span>, notably the rare cortical subsets, were significantly enhanced with Liberase products containing medium to high levels of thermolysin. The improved stromal dissociation led to numerically increased <span class="hlt">TEC</span> yield and total <span class="hlt">TEC</span> RNA isolated from pooled digests of adult thymus. Furthermore, the increased recovery of <span class="hlt">TEC</span> enhanced resolution and quantification of <span class="hlt">TEC</span> subsets in both adult and aged mice, facilitating flow cytometric analysis on a per thymus basis. We further refined the adult <span class="hlt">TEC</span> phenotype by correlating surface expression of known <span class="hlt">TEC</span> markers, with expression of intracellular epithelial lineage markers, Keratin 5 and Keratin 8. The data reveal more extensive expression of K8 than previously recognized and indicates considerable heterogeneity still exists within</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23018418','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23018418"><span>Detection of abnormalities in the superficial zone of cartilage repaired using a tissue engineered construct derived from synovial stem cells.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ando, Wataru; Fujie, Hiromichi; Moriguchi, Yu; Nansai, Ryosuke; Shimomura, Kazunori; Hart, David A; Yoshikawa, Hideki; Nakamura, Norimasa</p> <p>2012-09-28</p> <p>The present study investigated the surface structure and mechanical properties of repair cartilage generated from a tissue engineered construct (<span class="hlt">TEC</span>) derived from synovial mesenchymal stem cells at six months post-implantation compared to those of uninjured cartilage. <span class="hlt">TEC</span>-mediated repair tissue was cartilaginous with Safranin O staining, and had comparable macro-scale compressive properties with uninjured cartilage. However, morphological assessments revealed that the superficial zone of <span class="hlt">TEC</span>-mediated tissue was more fibrocartilage-like, in contrast to the middle or deep zones that were more hyaline cartilage-like with Safranin O staining. Histological scoring of the <span class="hlt">TEC</span>-mediated tissue was significantly lower in the superficial zone than in the middle and deep zones. Scanning electron microscopy showed a thick tangential bundle of collagen fibres at the most superficial layer of uninjured cartilage, while no corresponding structure was detected at the surface of <span class="hlt">TEC</span>-mediated tissue. Immunohistochemical analysis revealed that PRG4 was localised in the superficial area of uninjured cartilage, as well as the <span class="hlt">TEC</span>-mediated tissue. Friction testing showed that the lubrication properties of the two tissues was similar, however, micro-indentation analysis revealed that the surface stiffness of the <span class="hlt">TEC</span>-repair tissue was significantly lower than that of uninjured cartilage. Permeability testing indicated that the <span class="hlt">TEC</span>-mediated tissue exhibited lower water retaining capacity than did uninjured cartilage, specifically at the superficial zone. Thus, <span class="hlt">TEC</span>-mediated tissue exhibited compromised mechanical properties at the superficial zone, properties which need improvement in the future for maintenance of long term repair cartilage integrity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24996059','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24996059"><span>A pilot study comparing the use of Thiel- and formalin-embalmed cadavers in the teaching of human anatomy.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Balta, Joy Y; Lamb, Clare; Soames, Roger W</p> <p>2015-01-01</p> <p>Formalin had traditionally been used to preserve human material to teach gross anatomy. In 2008 the Centre for Anatomy and Human Identification (CAHID) at the University of Dundee embarked on the use of the Thiel method of embalming. The aim of this pilot study was to assess the difference between formalin-embalmed cadavers (FEC) and Thiel-embalmed cadavers (<span class="hlt">TEC</span>) used for teaching and surgical training. Three different questionnaires were prepared for data collection from undergraduate and postgraduate students and clinical staff. All undergraduate and postgraduate students as well as clinical staff commented on the appearance of the <span class="hlt">TEC</span>. There was no overall consensus concerning the use of <span class="hlt">TEC</span>, some respondents preferred <span class="hlt">TEC</span> for the entire dissection, some only for certain areas such as the musculoskeletal system. On a technical level <span class="hlt">TEC</span> were considered less hazardous then FEC by one-third of participants with fewer than 10% regarding <span class="hlt">TEC</span> as more irritating than FEC. Psychologically, 32.7% of undergraduate students expressed the view that <span class="hlt">TEC</span> made them feel more uncomfortable compared with FEC because of their life-like appearance. However, 57.1% of undergraduate students encountered the same uncomfortable feelings when viewing both <span class="hlt">TEC</span> and FEC. The use of Thiel-embalmed cadavers to teach anatomy has an added value, though further research is required over longer periods of time to identify its best usage. © 2014 American Association of Anatomists.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28158249','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28158249"><span>RB inactivation in keratin 18 positive thymic epithelial cells promotes non-cell autonomous T cell hyperproliferation in genetically engineered mice.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Song, Yurong; Sullivan, Teresa; Klarmann, Kimberly; Gilbert, Debra; O'Sullivan, T Norene; Lu, Lucy; Wang, Sophie; Haines, Diana C; Van Dyke, Terry; Keller, Jonathan R</p> <p>2017-01-01</p> <p>Thymic epithelial cells (<span class="hlt">TEC</span>), as part of thymic stroma, provide essential growth factors/cytokines and self-antigens to support T cell development and selection. Deletion of Rb family proteins in adult thymic stroma leads to T cell hyperplasia in vivo. To determine whether deletion of Rb specifically in keratin (K) 18 positive <span class="hlt">TEC</span> was sufficient for thymocyte hyperplasia, we conditionally inactivated Rb and its family members p107 and p130 in K18+ <span class="hlt">TEC</span> in genetically engineered mice (TgK18GT121; K18 mice). We found that thymocyte hyperproliferation was induced in mice with Rb inactivation in K18+ <span class="hlt">TEC</span>, while normal T cell development was maintained; suggesting that inactivation of Rb specifically in K18+ <span class="hlt">TEC</span> was sufficient and responsible for the phenotype. Transplantation of wild type bone marrow cells into mice with Rb inactivation in K18+ <span class="hlt">TEC</span> resulted in donor T lymphocyte hyperplasia confirming the non-cell autonomous requirement for Rb proteins in K18+ <span class="hlt">TEC</span> in regulating T cell proliferation. Our data suggests that thymic epithelial cells play an important role in regulating lymphoid proliferation and thymus size.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5497495','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5497495"><span>Molecular checkpoint decisions made by subverted vascular niche transform indolent tumor cells into chemoresistant cancer stem cells</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Cao, Zhongwei; Scandura, Joseph M; Inghirami, Giorgio G.; Shido, Koji; Ding, Bi-Sen; Rafii, Shahin</p> <p>2017-01-01</p> <p>Summary Tumor-associated endothelial cells (<span class="hlt">TECs</span>) regulate tumor cell aggressiveness. However, the “core” mechanism by which <span class="hlt">TECs</span> confer stem cell-like activity to indolent tumors is unknown. Here, we used in vivo murine and human tumor models to identify tumor-suppressive checkpoint role of <span class="hlt">TEC</span>-expressed insulin growth factor (IGF) binding protein-7 (IGFBP7/angiomodulin). During tumorigenesis, IGFBP7 blocks IGF1 and inhibits expansion and engraftment of tumor stem-like cells (TSCs) expressing IGF1-receptor (IGF1R). However, chemotherapy triggers <span class="hlt">TECs</span> to suppress IGFBP7, and this stimulates IGF1R+ TSCs to express FGF4, inducing a feed-forward FGFR1-ETS2 angiocrine cascade that obviates <span class="hlt">TEC</span> IGFBP7. Thus, loss of IGFBP7 and upregulation of IGF1 activates the FGF4-FGFR1-ETS2 pathway in <span class="hlt">TECs</span> and converts naive tumor cells to chemoresistant TSCs, thereby facilitating their engraftment and progression. PMID:27989801</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27989801','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27989801"><span>Molecular Checkpoint Decisions Made by Subverted Vascular Niche Transform Indolent Tumor Cells into Chemoresistant Cancer Stem Cells.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cao, Zhongwei; Scandura, Joseph M; Inghirami, Giorgio G; Shido, Koji; Ding, Bi-Sen; Rafii, Shahin</p> <p>2017-01-09</p> <p>Tumor-associated endothelial cells (<span class="hlt">TECs</span>) regulate tumor cell aggressiveness. However, the core mechanism by which <span class="hlt">TECs</span> confer stem cell-like activity to indolent tumors is unknown. Here, we used in vivo murine and human tumor models to identify the tumor-suppressive checkpoint role of <span class="hlt">TEC</span>-expressed insulin growth factor (IGF) binding protein-7 (IGFBP7/angiomodulin). During tumorigenesis, IGFBP7 blocks IGF1 and inhibits expansion and aggresiveness of tumor stem-like cells (TSCs) expressing IGF1 receptor (IGF1R). However, chemotherapy triggers <span class="hlt">TECs</span> to suppress IGFBP7, and this stimulates IGF1R + TSCs to express FGF4, inducing a feedforward FGFR1-ETS2 angiocrine cascade that obviates <span class="hlt">TEC</span> IGFBP7. Thus, loss of IGFBP7 and upregulation of IGF1 activates the FGF4-FGFR1-ETS2 pathway in <span class="hlt">TECs</span> and converts naive tumor cells to chemoresistant TSCs, thereby facilitating their invasiveness and progression. Copyright © 2017 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..122.2151T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..122.2151T"><span>A statistical study of global ionospheric map total electron content changes prior to occurrences of M ≥ 6.0 earthquakes during 2000-2014</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thomas, J. N.; Huard, J.; Masci, F.</p> <p>2017-02-01</p> <p>There are many reports on the occurrence of anomalous changes in the ionosphere prior to large earthquakes. However, whether or not these changes are reliable precursors that could be useful for earthquake prediction is controversial within the scientific community. To test a possible statistical relationship between ionospheric disturbances and earthquakes, we compare changes in the total electron content (<span class="hlt">TEC</span>) of the ionosphere with occurrences of M ≥ 6.0 earthquakes globally for 2000-2014. We use <span class="hlt">TEC</span> data from the global ionosphere map (GIM) and an earthquake list declustered for aftershocks. For each earthquake, we look for anomalous changes in GIM-<span class="hlt">TEC</span> within 2.5° latitude and 5.0° longitude of the earthquake location (the spatial resolution of GIM-<span class="hlt">TEC</span>). Our analysis has not found any statistically significant changes in GIM-<span class="hlt">TEC</span> prior to earthquakes. Thus, we have found no evidence that would suggest that monitoring changes in GIM-<span class="hlt">TEC</span> might be useful for predicting earthquakes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JASTP.120...15P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JASTP.120...15P"><span>Ionospheric effects of sudden stratospheric warmings in eastern Siberia region</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Polyakova, A. S.; Chernigovskaya, M. A.; Perevalova, N. P.</p> <p>2014-12-01</p> <p>Ionospheric effects observed in Russia's Asia region during sudden stratospheric warmings (SSWs) in the winters 2008/2009 and 2012/2013 corresponding to both extreme solar minimum and moderate solar maximum conditions have been examined. To detect the ionospheric effects which must have been induced by the SSWs, we have carried out a joint analysis of total electron content (<span class="hlt">TEC</span>) global ionospheric maps (GIM), MLS (Microwave Limb Sounder, EOS Aura) measurements of vertical temperature profiles, as well as NCEP/NCAR and UKMO Reanalysis data. It has been revealed for the first time that during strong SSWs the amplitude of diurnal variation of <span class="hlt">TEC</span> decreases nearly by half in the mid-latitude ionosphere. Besides, the intensity of <span class="hlt">TEC</span> deviations from the background level increases during SSWs. It has also revealed that during SSW peak the midday <span class="hlt">TEC</span> maximum considerably decreases, and the night/morning <span class="hlt">TEC</span> increases compared to quiet days. The pattern of <span class="hlt">TEC</span> response to SSW is shown to be identical for both quiet and disturbed geophysical conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..122.6892M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..122.6892M"><span>Observation of subsecond variations in auroral region total electron content using 100 Hz sampling of GPS observables</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McCaffrey, A. M.; Jayachandran, P. T.</p> <p>2017-06-01</p> <p>First ever auroral region total electron content (<span class="hlt">TEC</span>) measurements at 100 Hz using a Septentrio PolaRxS Pro receiver are analyzed to discover ionospheric signatures which would otherwise be unobtainable with the frequently used lower sampling rates. Two types of variations are observed: small-magnitude (amplitude) variations, which are present consistently throughout the data set, and larger-magnitude (amplitude) variations, which are less frequent. Small-amplitude <span class="hlt">TEC</span> fluctuations are accounted for by the receiver phase jitter. However, estimated secondary ionospheric effects in the calculation of <span class="hlt">TEC</span> and the receiver phase jitter were unable to account for the larger-amplitude <span class="hlt">TEC</span> fluctuations. These variations are also accompanied by fluctuations in the magnetic field, which seems to indicate that these fluctuations are real and of geophysical significance. This paper presents a technique and the capability of high-rate <span class="hlt">TEC</span> measurements in the study of auroral dynamics. Further detailed study is needed to identify the cause of these subsecond <span class="hlt">TEC</span> fluctuations and associated magnetic field fluctuations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AdSpR..58..598A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AdSpR..58..598A"><span>The study of variability of <span class="hlt">TEC</span> over mid-latitude American regions during the ascending phase of solar cycle 24 (2009-2011)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Asmare Tariku, Yekoye</p> <p>2016-08-01</p> <p>This paper deals with the pattern of the variability of the Global Positioning System vertical total electron content (GPS VTEC) and the modeled vertical total electron content (IRI 2012 <span class="hlt">TEC</span>) over American mid-latitude regions during the rising phase of solar cycle 24 (2009-2011). This has been conducted employing ground-based dual frequency GPS receiver installed at Mississippi County Airport (geographic lat. 36.85°N and long. 270.64°E). In this work, the monthly and seasonal variations in the measured VTEC have been analyzed and compared with the VTEC inferred from IRI-2012 model. It has been shown that the monthly and seasonal mean VTEC values get decreased mostly between 05:00 and 10:00 UT and reach their minimal nearly at around 10:00 UT for both the experimental and the model. The VTEC values then get increased and reach the peak values at around 20:00 UT and decrease again. Moreover, it is depicted that the model better estimates both the monthly and seasonal mean hourly VTEC values mostly between 15:00 and 20:00 UT. The modeled monthly and seasonal VTEC values are smaller than the corresponding measured values as the solar activity decreases when all options for the topside electron density are used. However, as the Sun goes from a very low to a high solar activity, the overestimation performance of the VTEC values derived from the model increases. The overall results show that it is generally better to use the model with IRI-2000 option for the topside electron density in estimating the monthly and seasonal VTEC variations, especially when the activity of the Sun decreases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.7249D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.7249D"><span>Investigation of Ionospheric Precursors of 23 October 2011, Mw=7.2 Earthquake in Van, Turkey</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Deviren, M. N.; Arikan, F.; Sezen, U.; Arikan, O.</p> <p>2012-04-01</p> <p>In recent years, a strong coupling between ionospheric disturbances and seismic activity has been observed through the increase of ion temperatures, critical frequencies of ionospheric layers and Total Electron Content (<span class="hlt">TEC</span>) before high magnitude earthquakes. <span class="hlt">TEC</span> is defined as total number of electrons over a ray path through the ionosphere. <span class="hlt">TEC</span> can be estimated in a cost-effective way with dual-frequency Global Positioning Satellite (GPS) System receivers. The unit of <span class="hlt">TEC</span> is given by TECU where 1 TECU = 1016 el/m2. In this study, the disturbances in daily <span class="hlt">TEC</span> values before 23 October 2011, Mw=7.2 Earthquake in Van, Turkey are investigated using Turkish National Permanent GPS Network (TNPGN-Active). Earthquake Day Period (EDP) is chosen between October 1 and 31, 2011. Daily <span class="hlt">TEC</span> values, for each station and each day, are estimated as IONOLAB-<span class="hlt">TEC</span> (www.ionolab.org ) with 30 s time resolution. EDP-<span class="hlt">TEC</span> values are compared with an Average Quiet Day <span class="hlt">TEC</span> (AQDT) which is obtained by averaging the <span class="hlt">TEC</span> values between 25 and 28 March, 2011. Statistical comparison is accomplished using Symmetric Kullback-Leibler Divergence (SKLD), which is also a method for measuring entropy of a system. It has been previously observed that SKLD is a better method for measuring the amount of disturbances compared to L2 norm and cross-correlation coefficient. AQDT is also compared with magnetically Quiet Day Period (QDP) from 25 to 28 April, 2011, during which Kp and Dst indices indicate a very quiet ionospheric and magnetospheric period. Also, in order to measure the variability between the consecutive days, <span class="hlt">TEC</span> values for each day during EDP and QDP are compared with the <span class="hlt">TEC</span> values of the following day. A third measure of W-index is also applied to identify the local disturbances in the ionosphere, where <span class="hlt">TEC</span> of a given day is compared to the median of seven days prior to the day of investigation logarithmically. Since W-index is obtained for each epoch, the within-the-day variability can also</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.3941S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.3941S"><span>Real-Time Detection of Tsunami Ionospheric Disturbances with a Stand-Alone GNSS Receiver: An Integration of GPS and Galileo Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Savastano, Giorgio; Komjathy, Attila; Verkhoglyadova, Olga; Wei, Yong; Mazzoni, Augusto; Crespi, Mattia</p> <p>2017-04-01</p> <p>Tsunamis can produce gravity waves that propagate up to the ionosphere generating disturbed electron densities in the E and F regions. These ionospheric disturbances are studied in detail using ionospheric total electron content (<span class="hlt">TEC</span>) measurements collected by continuously operating ground-based receivers from the Global Navigation Satellite Systems (GNSS). Here, we present results using a new approach, named VARION (Variometric Approach for Real-Time Ionosphere Observation), and for the first time, we estimate slant <span class="hlt">TEC</span> (s<span class="hlt">TEC</span>) variations in a real-time scenario from GPS and Galileo constellations. Specifically, we study the 2016 New Zealand tsunami event using GNSS receivers with multi-constellation tracking capabilities located in the Pacific region. We compare s<span class="hlt">TEC</span> estimates obtained using GPS and Galileo constellations. The efficiency of the real-time s<span class="hlt">TEC</span> estimation using the VARION algorithm has been demonstrated for the 2012 Haida Gwaii tsunami event. <span class="hlt">TEC</span> variations induced by the tsunami event are computed using 56 GPS receivers in Hawai'i. We observe <span class="hlt">TEC</span> perturbations with amplitudes up to 0.25 <span class="hlt">TEC</span> units and traveling ionospheric disturbances moving away from the epicenter at a speed of about 316 m/s. We present comparisons with the real-time tsunami model MOST (Method of Splitting Tsunami) provided by the NOAA Center for Tsunami Research. We observe variations in <span class="hlt">TEC</span> that correlate well in time and space with the propagating tsunami waves. We conclude that the integration of different satellite constellations is a crucial step forward to increasing the reliability of real-time tsunami detection systems using ground-based GNSS receivers as an augmentation to existing tsunami early warning systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999JGR...10422553B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999JGR...10422553B"><span>Simultaneous Global Positioning System observations of equatorial scintillations and total electron content fluctuations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beach, Theodore L.; Kintner, Paul M.</p> <p>1999-10-01</p> <p>One aspect of the Global Positioning System (GPS) is the potential to conduct geophysical research, and worldwide networks of GPS receivers have been established to exploit this potential. Several research groups have begun using this global GPS data to study ionospheric total electron content (<span class="hlt">TEC</span>) variations, also referred to as GPS phase fluctuations, as surrogates for ionospheric scintillations. This paper investigates the relationship between GPS amplitude scintillations and <span class="hlt">TEC</span> variations for the same line of sight using observations from Ancón, Peru. These observations were taken under equatorial spread F conditions for three nights in April 1997. As expected, only when the spectrum of <span class="hlt">TEC</span> fluctuations includes significant power at the Fresnel scale do scintillations appear. We also find that when the <span class="hlt">TEC</span> fluctuation spectrum includes the Fresnel scale, the S4 scintillation index is roughly proportional to measures of <span class="hlt">TEC</span> fluctuation for the weak scintillations observed. The proportionality constant varies from night to night, however, casting doubt on the ability to predict GPS S4 successfully from <span class="hlt">TEC</span> fluctuation data alone. We also present a simple theoretical phase screen model and show that if a relationship between <span class="hlt">TEC</span> fluctuation measures and S4 exists, that relationship depends on the power spectrum of phase variations at the screen. Unfortunately, the available <span class="hlt">TEC</span> data, at 30 s per sample (with some aliasing apparently permitted), offer limited spectral information. A preliminary comparison of 1 s/sample data with the same data decimated to a 30 s/sample interval suggests, however, that the level of successful S4 prediction, based on <span class="hlt">TEC</span> fluctuation measures alone, is comparable at either sample rate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8481E..04S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8481E..04S"><span>Preparing technicians for photonics industries and organizations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Souders, John; Hull, Dan</p> <p>2012-10-01</p> <p>U.S. photonics organizations need about 800 new photonics technicians each year. Thirty-one community and technical colleges have approximately 700 students enrolled in photonics related programs; about 275 of them complete their coursework and enter the workforce each year. A disparity exists between the demand and supply of qualified photonics technicians in the U.S. OP-<span class="hlt">TEC</span>, the National Center for Optics and Photonics Education is a consortium of seven colleges, under the leadership of the University of Central Florida, and sponsored by NSF. OP-<span class="hlt">TEC</span>'s mission is to increase the quantity and quality of photonics technicians prepared at two-year colleges. OP-<span class="hlt">TEC</span> maintains the National Photonics Skill Standards for Technicians, provides curriculum models, teaching materials, faculty training/professional development and planning services to strengthen existing college photonics programs and to attract and support new ones. OP-<span class="hlt">TEC</span> is converting its text materials to E-Books to support students in technical programs. Through OP-<span class="hlt">TEC</span>'s recruitment efforts 84 additional colleges are interested in initiating new photonics programs. The OP-<span class="hlt">TEC</span> Photonics College Network (OPCN) consists of 28 colleges that are currently providing photonics education. This fall OPCN will lead an additional national effort to further educate employed photonics technicians through on-line courses, complemented by lab experiences at nearby colleges. OP-<span class="hlt">TEC</span> is expanding its outreach to photonics employers and colleges by regionalizing its approach to offering its services. OP-<span class="hlt">TEC</span> is also planning to develop new curricula and instructional materials for AAS programs to prepare Precision Optics Technicians. This paper will detail OP-<span class="hlt">TEC</span>'s work with particular emphases on its materials and services.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMNH21C1845T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMNH21C1845T"><span>A Statistical Study of Total Electron Content Changes in the Ionosphere Prior to Earthquake Occurrences</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thomas, J. N.; Huard, J.; Masci, F.</p> <p>2015-12-01</p> <p>There are many published reports of anomalous changes in the ionosphere prior to large earthquakes. However, whether or not these ionospheric changes are reliable precursors that could be useful for earthquake prediction is controversial within the scientific community. To test a possible statistical relationship between the ionosphere and earthquakes, we compare changes in the total electron content (<span class="hlt">TEC</span>) of the ionosphere with occurrences of M≥6.0 earthquakes globally for a multiyear period. We use <span class="hlt">TEC</span> data from a global ionosphere map (GIM) and an earthquake list declustered for aftershocks. For each earthquake, we look for anomalous changes in <span class="hlt">TEC</span> within ±30 days of the earthquake time and within 2.5° latitude and 5.0° longitude of the earthquake location (the spatial resolution of GIM). Our preliminary analysis, using global <span class="hlt">TEC</span> and earthquake data for 2002-2010, has not found any statistically significant changes in <span class="hlt">TEC</span> prior to earthquakes. Thus, we have found no evidence that would suggest that <span class="hlt">TEC</span> changes are useful for earthquake prediction. Our results are discussed in the context of prior statistical and case studies. Namely, our results agree with Dautermann et al. (2007) who found no relationship between <span class="hlt">TEC</span> changes and earthquakes in the San Andreas fault region. Whereas, our results disagree with Le et al. (2011) who found an increased rate in <span class="hlt">TEC</span> anomalies within a few days before global earthquakes M≥6.0.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSA31D2369Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSA31D2369Z"><span>Long Duration Enhancement And Depletion Observed In The Topside Ionospheric Electron Content During The March 2015 Strong Storm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhong, J.; Wang, W.; Yue, X.; Burns, A. G.; Dou, X.; Lei, J.</p> <p>2015-12-01</p> <p>Up-looking total electron content (<span class="hlt">TEC</span>) measurements from multiple low Earth orbit (LEO) satellites have been utilized to study the topside ionospheric response to the 17 March 2015 great storm. The combined up-looking <span class="hlt">TEC</span> observations from these LEO satellites are valuable in addressing the local time and altitudinal dependences of the topside ionospheric response to geomagnetic storms from a global perspective, especially over the southern hemisphere and oceans. In the evening sector, the up-looking <span class="hlt">TEC</span> showed an obvious long-duration of positive storm effect during the main phase and a long duration of negative storm effect during the recovery phase of this storm. The increases of the topside <span class="hlt">TEC</span> during the main phase were symmetric with respect to the magnetic equator, which was probably associated with penetration electric fields. Additionally, the up-looking <span class="hlt">TEC</span> from different orbital altitudes suggested that the negative storm effect at higher altitudes was stronger in the evening sector. In the morning sector, the up-looking <span class="hlt">TEC</span> also showed increases at low and middle latitudes during the storm main phase. Obvious <span class="hlt">TEC</span> enhancement can be also seen over the Pacific Ocean in the topside ionosphere during the storm recovery phase. These results imply that the topside ionospheric responses significantly depend on local time. Thus, the LEO-based up-looking <span class="hlt">TEC</span> provides an important database to study the possible physical mechanisms of the topside ionospheric response to storms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AnGeo..35.1309M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AnGeo..35.1309M"><span>Total electron content responses to HILDCAAs and geomagnetic storms over South America</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mara de Siqueira Negreti, Patricia; Rodrigues de Paula, Eurico; Nicoli Candido, Claudia Maria</p> <p>2017-12-01</p> <p>Total electron content (<span class="hlt">TEC</span>) is extensively used to monitor the ionospheric behavior under geomagnetically quiet and disturbed conditions. This subject is of greatest importance for space weather applications. Under disturbed conditions the two main sources of electric fields, which are responsible for changes in the plasma drifts and for current perturbations, are the short-lived prompt penetration electric fields (PPEFs) and the longer-lasting ionospheric disturbance dynamo (DD) electric fields. Both mechanisms modulate the <span class="hlt">TEC</span> around the globe and the equatorial ionization anomaly (EIA) at low latitudes. In this work we computed vertical absolute <span class="hlt">TEC</span> over the low latitude of South America. The analysis was performed considering HILDCAA (high-intensity, long-duration, continuous auroral electrojet (AE) activity) events and geomagnetic storms. The characteristics of storm-time <span class="hlt">TEC</span> and HILDCAA-associated <span class="hlt">TEC</span> will be presented and discussed. For both case studies presented in this work (March and August 2013) the HILDCAA event follows a geomagnetic storm, and then a global scenario of geomagnetic disturbances will be discussed. Solar wind parameters, geomagnetic indices, O / N2 ratios retrieved by GUVI instrument onboard the TIMED satellite and <span class="hlt">TEC</span> observations will be analyzed and discussed. Data from the RBMC/IBGE (Brazil) and IGS GNSS networks were used to calculate <span class="hlt">TEC</span> over South America. We show that a HILDCAA event may generate larger <span class="hlt">TEC</span> differences compared to the <span class="hlt">TEC</span> observed during the main phase of the precedent geomagnetic storm; thus, a HILDCAA event may be more effective for ionospheric response in comparison to moderate geomagnetic storms, considering the seasonal conditions. During the August HILDCAA event, <span class="hlt">TEC</span> enhancements from ˜ 25 to 80 % (compared to quiet time) were observed. These enhancements are much higher than the quiet-time variability observed in the ionosphere. We show that ionosphere is quite sensitive to solar wind forcing and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4060646','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4060646"><span>Coliphage HK022 Nun protein inhibits RNA polymerase translocation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Vitiello, Christal L.; Kireeva, Maria L.; Lubkowska, Lucyna; Kashlev, Mikhail; Gottesman, Max</p> <p>2014-01-01</p> <p>The Nun protein of coliphage HK022 arrests RNA polymerase (RNAP) in vivo and in vitro at pause sites distal to phage λ N-Utilization (nut) site RNA sequences. We tested the activity of Nun on ternary elongation complexes (<span class="hlt">TECs</span>) assembled with templates lacking the λ nut sequence. We report that Nun stabilizes both translocation states of RNAP by restricting lateral movement of <span class="hlt">TEC</span> along the DNA register. When Nun stabilized <span class="hlt">TEC</span> in a pretranslocated register, immediately after NMP incorporation, it prevented binding of the next NTP and stimulated pyrophosphorolysis of the nascent transcript. In contrast, stabilization of <span class="hlt">TEC</span> by Nun in a posttranslocated register allowed NTP binding and nucleotidyl transfer but inhibited pyrophosphorolysis and the next round of forward translocation. Nun binding to and action on the <span class="hlt">TEC</span> requires a 9-bp RNA–DNA hybrid. We observed a Nun-dependent toe print upstream to the <span class="hlt">TEC</span>. In addition, mutations in the RNAP β′ subunit near the upstream end of the transcription bubble suppress Nun binding and arrest. These results suggest that Nun interacts with RNAP near the 5′ edge of the RNA–DNA hybrid. By stabilizing translocation states through restriction of <span class="hlt">TEC</span> lateral mobility, Nun represents a novel class of transcription arrest factors. PMID:24853501</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSA11A1916W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSA11A1916W"><span>Dual-band beacon experiment over Southeast Asia for ionospheric irregularity analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Watthanasangmechai, K.; Yamamoto, M.; Saito, A.; Saito, S.; Maruyama, T.; Tsugawa, T.; Nishioka, M.</p> <p>2013-12-01</p> <p>An experiment of dual-band beacon over Southeast Asia was started in March 2012 in order to capture and analyze ionospheric irregularities in equatorial region. Five GNU Radio Beacon Receivers (GRBRs) were aligned along 100 degree geographic longitude. The distances between the stations reach more than 500 km. The field of view of this observational network covers +/- 20 degree geomagnetic latitude including the geomagnetic equator. To capture ionospheric irregularities, the absolute <span class="hlt">TEC</span> estimation technique was developed. The two-station method (Leitinger et al., 1975) is generally accepted as a suitable method to estimate <span class="hlt">TEC</span> offsets of dual-band beacon experiment. However, the distances between the stations directly affect on the robustness of the technique. In Southeast Asia, the observational network is too sparse to attain a benefit of the classic two-station method. Moreover, the least-squares approch used in the two-station method tries too much to adjust the small scales of the <span class="hlt">TEC</span> distribution which are the local minima. We thus propose a new technique to estimate the <span class="hlt">TEC</span> offsets with the supporting data from absolute GPS-<span class="hlt">TEC</span> from local GPS receivers and the ionospheric height from local ionosondes. The key of the proposed technique is to utilize the brute-force technique with weighting function to find the <span class="hlt">TEC</span> offset set that yields a global minimum of RMSE in whole parameter space. The weight is not necessary when the <span class="hlt">TEC</span> distribution is smooth, while it significantly improves the <span class="hlt">TEC</span> estimation during the ESF events. As a result, the latitudinal <span class="hlt">TEC</span> shows double-hump distribution because of the Equatorial Ionization Anomaly (EIA). In additions, the 100km-scale fluctuations from an Equatorial Spread F (ESF) are captured at night time in equinox seasons. The plausible linkage of the meridional wind with triggering of ESF is under invatigating and will be presented. The proposed method is successful to estimate the latitudinal <span class="hlt">TEC</span> distribution from dual</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100019564','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100019564"><span>Thermoelectric Converter for Loop Heat Pipe Temperature Control: Experience and Lessons Learned</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ku, Jentung; Ottenstein, Laura</p> <p>2010-01-01</p> <p>This paper describes the theoretical background and implementation methodology of using a thermoelectric converter (<span class="hlt">TEC</span>) for operating temperature control of a loop heat pipe (LHP). In particular, experimental results from ambient and thermal vacuum tests of an LHP are presented for illustrations. The most commonly used state-of-the-art method to control the LHP operating temperature is to cold bias its compensation chamber (CC) and use an electrical heater to maintain the CC at the desired set point temperature. Although effective, this approach has its shortcomings in that the electrical heater can only provide heating to the CC, and the required power can be large under certain conditions. An alternative method is to use a <span class="hlt">TEC</span>, which is capable of providing both heating and cooling to the CC. In this method, one side of the <span class="hlt">TEC</span> is attached to the CC, and the other side is connected to the evaporator via a thermal strap. Using a bipolar power supply and a control algorithm, a <span class="hlt">TEC</span> can function as a heater or a cooler, depending on the direction of the current flow. Extensive ground tests of several LHPs have demonstrated that a <span class="hlt">TEC</span> can provide very tight temperature control for the CC. It also offers several additional advantages: (1) The LHP can operate at temperatures below its natural operating temperature at low heat loads; (2) The required heater power for a <span class="hlt">TEC</span> is much less than that for an electrical heater; and (3) It enhances the LHP start-up success. Although the concept of using a <span class="hlt">TEC</span> for LHP temperature control is simple, there are many factors to be considered in its implementation for space applications because the <span class="hlt">TEC</span> is susceptible to the shear stress and yet has to sustain the dynamic load under the spacecraft launch environment. The added features that help the <span class="hlt">TEC</span> to withstand the dynamic load will inevitably affect the <span class="hlt">TEC</span> thermal performance. Some experiences and lessons learned are addressed in this paper.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19790029086&hterms=nuclear+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dnuclear%2Benergy','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19790029086&hterms=nuclear+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dnuclear%2Benergy"><span>Optimize out-of-core thermionic energy conversion for nuclear electric propulsion</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Morris, J. F.</p> <p>1978-01-01</p> <p>Thermionic energy conversion (<span class="hlt">TEC</span>) potentialities for nuclear electric propulsion (NEP) are examined. Considering current designs, their limitations, and risks raises critical questions about the use of <span class="hlt">TEC</span> for NEP. Apparently a reactor cooled by hotter-than-1675 K heat pipes has good potentialities. <span class="hlt">TEC</span> with higher temperatures and greater power densities than the currently proposed 1650 K, 5-to-6 W/sq cm version offers substantial gains. Other approaches to high-temperature electric isolation appear also promising. A high-power-density, high-temperature <span class="hlt">TEC</span> for NEP appears, therefore, attainable. It is recommended to optimize out-of-core thermionic energy conversion for nuclear electric propulsion. Although current <span class="hlt">TEC</span> designs for NEP seem unnecessary compared with Brayton versions, large gains are apparently possible with increased temperatures and greater power densities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070030119','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070030119"><span>Loop Heat Pipe Operation with Thermoelectric Converters and Coupling Blocks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ku, Jentung; Nagano, Hosei</p> <p>2007-01-01</p> <p>This paper presents theoretical and experimental studies on using thermoelectric converters (<span class="hlt">TECs</span>) and coupling blocks to control the operating temperature of a miniature loop heat pipes (MLHP). The MLHP has two parallel evaporators and two parallel condensers, and each evaporator has its own integral compensation chamber (CC). A <span class="hlt">TEC</span> is attached to each CC, and connected to the evaporator via a copper thermal strap. The <span class="hlt">TEC</span> can provide both heating and cooling to the CC, therefore extending the LHP operating temperature over a larger range of the evaporator heat load. A bi-polar power supply is used for the <span class="hlt">TEC</span> operation. The bipolar power supply automatically changes the direction of the current to the <span class="hlt">TEC</span>, depending on whether the CC requires heating or cooling, to maintain the CC temperature at the desired set point. The <span class="hlt">TEC</span> can also enhance the startup success by maintaining a constant CC temperature during the start-up transient. Several aluminum coupling blocks are installed between the vapor line and liquid line. The coupling blocks serve as a heat exchanger which preheats the cold returning liquid so as to reduce the amount of liquid subcooling, and hence the power required to maintain the CC at the desired set point temperature. This paper focuses on the savings of the CC control heater power afforded by the <span class="hlt">TECs</span> when compared to traditional electric heaters. Tests were conducted by varying the evaporator power, the condenser sink temperature, the CC set point temperature, the number of coupling blocks, and the thermal conductance of the thermal strap. Test results show that the <span class="hlt">TECs</span> are able to control the CC temperature within k0.5K under all test conditions, and the required <span class="hlt">TEC</span> heater power is only a fraction of the required electric heater power.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15597347','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15597347"><span>In vitro evaluation of COM.<span class="hlt">TEC</span> apheresis platelet concentrates using a preparation set and pathogen inactivation over a storage period of five days.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Moog, R; Fröhlich, A; Mayaudon, V; Lin, L</p> <p>2004-01-01</p> <p>The aim of the present study was to evaluate in vitro data on platelets collected by apheresis, processed on a preparation set followed by photochemical treatment (PCT). Fifteen single-donor platelet concentrates (PCs) were collected by apheresis (COM.<span class="hlt">TEC</span> blood cell separator, Fresenius, Bad Homburg, Germany). The platelets were transferred to the preparation set and plasma was removed after centrifugation to resuspend the platelets in approximately 37% plasma and 63% platelet additive solution InterSol. PCT was done by exposing the platelets to amotosalen HCl followed by illumination with ultraviolet light. Blood cell counts and in vitro PLT function were measured up to 5 days. An average of 3.44 +/- 0.28 x 10(11) platelets were collected in a product volume of 351 +/- 21 mL. Plasma removal resulted in a mean platelet loss of 7.8%. After PCT, a progressive decrease in platelet function was observed. LDH level rose through storage (171 +/- 81 U/L) to levels approximating LDH levels observed post-collection (180 +/- 103 U/L). There was a gradual decrease of the platelets to respond to hypotonic shock response from 90 +/- 9 % post-plasma reduction to 48 +/- 16% at day 5. All PLT units met the European requirements for leukoreduction and the pH limit of 6.8 up to day 5 post-collection. The new preparation set was capable of producing platelet units meeting the requirements for PCT. Despite differences observed in in vitro platelet function parameters, PLTs at storage day 5 fit the German and European guidelines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24135055','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24135055"><span>Culture promotes transfer of thyroid epithelial cell hyperplasia and proliferation by reducing regulatory T cell numbers.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kayes, Timothy D; Braley-Mullen, Helen</p> <p>2013-01-01</p> <p>IFN-γ(-/-) NOD.H-2h4 mice develop a spontaneous autoimmune thyroid disease, thyroid epithelial cell hyperplasia and proliferation (<span class="hlt">TEC</span> H/P) when given NaI in their water for 7+ mo. <span class="hlt">TEC</span> H/P can be transferred to IFN-γ(-/-) SCID mice by splenocytes from mice with severe (4-5+) disease, and transfer of <span class="hlt">TEC</span> H/P is improved when splenocytes are cultured prior to transfer. Older (9+ mo) IFN-γ(-/-) NOD.H-2h4 mice have elevated numbers of FoxP3(+) T reg cells, up to 2-fold greater than younger (2 mo) mice. During culture, the number of T reg decreases and this allows the improved transfer of <span class="hlt">TEC</span> H/P. Co-culture with IL-2 prior to transfer prevents the decrease of T reg and improves their in vitro suppressive ability resulting in reduced <span class="hlt">TEC</span> H/P in recipient mice. Therefore, culturing splenocytes improves transfer of <span class="hlt">TEC</span> H/P by reducing the number of T reg and IL-2 inhibits transfer by preserving T reg number and function. Copyright © 2013 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19880065377&hterms=BEACON&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DBEACON','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19880065377&hterms=BEACON&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DBEACON"><span>A comparison of mapped and measured total ionospheric electron content using global positioning system and beacon satellite observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lanyi, Gabor E.; Roth, Titus</p> <p>1988-01-01</p> <p>Total ionospheric electron contents (<span class="hlt">TEC</span>) were measured by global positioning system (GPS) dual-frequency receivers developed by the Jet Propulsion Laboratory. The measurements included P-code (precise ranging code) and carrier phase data for six GPS satellites during multiple five-hour observing sessions. A set of these GPS <span class="hlt">TEC</span> measurements were mapped from the GPS lines of sight to the line of sight of a Faraday beacon satellite by statistically fitting the <span class="hlt">TEC</span> data to a simple model of the ionosphere. The mapped GPS <span class="hlt">TEC</span> values were compared with the Faraday rotation measurements. Because GPS transmitter offsets are different for each satellite and because some GPS receiver offsets were uncalibrated, the sums of the satellite and receiver offsets were estimated simultaneously with the <span class="hlt">TEC</span> in a least squares procedure. The accuracy of this estimation procedure is evaluated indicating that the error of the GPS-determined line of sight <span class="hlt">TEC</span> can be at or below 1 x 10 to the 16th el/sq cm. Consequently, the current level of accuracy is comparable to the Faraday rotation technique; however, GPS provides superior sky coverage.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970026888','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970026888"><span>Correction of Single Frequency Altimeter Measurements for Ionosphere Delay</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schreiner, William S.; Markin, Robert E.; Born, George H.</p> <p>1997-01-01</p> <p>This study is a preliminary analysis of the accuracy of various ionosphere models to correct single frequency altimeter height measurements for Ionospheric path delay. In particular, research focused on adjusting empirical and parameterized ionosphere models in the parameterized real-time ionospheric specification model (PRISM) 1.2 using total electron content (<span class="hlt">TEC</span>) data from the global positioning system (GPS). The types of GPS data used to adjust PRISM included GPS line-of-sight (LOS) <span class="hlt">TEC</span> data mapped to the vertical, and a grid of GPS derived <span class="hlt">TEC</span> data in a sun-fixed longitude frame. The adjusted PRISM <span class="hlt">TEC</span> values, as well as predictions by IRI-90, a climatotogical model, were compared to TOPEX/Poseidon (T/P) <span class="hlt">TEC</span> measurements from the dual-frequency altimeter for a number of T/P tracks. When adjusted with GPS LOS data, the PRISM empirical model predicted <span class="hlt">TEC</span> over 24 1 h data sets for a given local time to with in a global error of 8.60 TECU rms during a midnight centered ionosphere and 9.74 TECU rms during a noon centered ionosphere. Using GPS derived sun-fixed <span class="hlt">TEC</span> data, the PRISM parameterized model predicted <span class="hlt">TEC</span> within an error of 8.47 TECU rms centered at midnight and 12.83 TECU rms centered at noon. From these best results, it is clear that the proposed requirement of 3-4 TECU global rms for TOPEX/Poseidon Follow-On will be very difficult to meet, even with a substantial increase in the number of GPS ground stations, with any realizable combination of the aforementioned models or data assimilation schemes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3059023','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3059023"><span>Absence of <span class="hlt">Tec</span> Family Kinases Interleukin-2 Inducible T cell Kinase (Itk) and Bruton's Tyrosine Kinase (Btk) Severely Impairs FcϵRI-dependent Mast Cell Responses*</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Iyer, Archana S.; Morales, J. Luis; Huang, Weishan; Ojo, Folake; Ning, Gang; Wills, Elizabeth; Baines, Joel D.; August, Avery</p> <p>2011-01-01</p> <p>Mast cells are critical effector cells in the pathophysiology of allergic asthma and other IgE-mediated diseases. The <span class="hlt">Tec</span> family of tyrosine kinases Itk and Btk serve as critical signal amplifiers downstream of antigen receptors. Although both kinases are expressed and activated in mast cells following FcϵRI stimulation, their individual contributions are not clear. To determine whether these kinases play unique and/or complementary roles in FcϵRI signaling and mast cell function, we generated Itk and Btk double knock-out mice. Analyses of these mice show decreased mast cell granularity and impaired passive systemic anaphylaxis responses. This impaired response is accompanied by a significant elevation in serum IgE in Itk/Btk double knock-out mice. In vitro analyses of bone marrow-derived mast cells (BMMCs) indicated that Itk/Btk double knock-out BMMCs are defective in degranulation and cytokine secretion responses downstream to FcϵRI activation. These responses were accompanied by a significant reduction in PLCγ2 phosphorylation and severely impaired calcium responses in these cells. This defect also results in altered NFAT1 nuclear localization in double knock-out BMMCs. Network analysis suggests that although they may share substrates, Itk plays both positive and negative roles, while Btk primarily plays a positive role in mast cell FcϵRI-induced cytokine secretion. PMID:21212279</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19810022431','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19810022431"><span>A program-management plan with critical-path definition for Combustion Augmentation with Thermionic Energy Conversion (CATEC)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Morris, J. F.; Merrill, O. S.; Reddy, H. K.</p> <p>1981-01-01</p> <p>Thermionic energy conversion (<span class="hlt">TEC</span>) is discussed. In recent <span class="hlt">TEC</span>-topping analyses, overall plant efficiency (OPE) and cost of electricity (COE) improved slightly with current capabilities and substantially with fully matured technologies. Enhanced credibility derives from proven hot-corrosion protection for <span class="hlt">TEC</span> by silicon-carbide clads in fossil fuel combustion products. Combustion augmentation with <span class="hlt">TEC</span> (CATEC) affords minimal cost and plant perturbation, but with smaller OPE and COE improvements than more conventional topping applications. Risk minimization as well as comparative simplicity and convenience, favor CATEC for early market penetration. A program-management plan is proposed. Inputs, characteristics, outputs and capabilities are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.2520L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.2520L"><span>Dust Storm Signatures in Global Ionosphere Map of GPS Total Electron Content</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lin, Fang-Tse; Shih, Ai-Ling; Liu, Jann-Yenq; Kuo, Cheng-Ling; Lin, Tang-Huang; Lien, Wei-Hung</p> <p>2016-04-01</p> <p>In this paper both MODIS data and GIM (global ionosphere map) <span class="hlt">TEC</span> (total electron content) as well as numerical simulations are used to study ionospheric dust storm effects in May 2008. The aerosol optical depth (AOD) and the LTT (latitude-time-<span class="hlt">TEC</span>) along the Sahara longitude simultaneously reach their maximum values on 28 May 2008. The LLT (latitude-longitude-<span class="hlt">TEC</span>) map specifically and significantly increases over the Sahara region on 28 May 2008. The simulation suggests that the dust storm may change the atmospheric conductivity, which in turn modifies the GIM <span class="hlt">TEC</span> over the Sahara area.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1981plsc.confR..18M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1981plsc.confR..18M"><span>A program-management plan with critical-path definition for Combustion Augmentation with Thermionic Energy Conversion (CATEC)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Morris, J. F.; Merrill, O. S.; Reddy, H. K.</p> <p></p> <p>Thermionic energy conversion (<span class="hlt">TEC</span>) is discussed. In recent <span class="hlt">TEC</span>-topping analyses, overall plant efficiency (OPE) and cost of electricity (COE) improved slightly with current capabilities and substantially with fully matured technologies. Enhanced credibility derives from proven hot-corrosion protection for <span class="hlt">TEC</span> by silicon-carbide clads in fossil fuel combustion products. Combustion augmentation with <span class="hlt">TEC</span> (CATEC) affords minimal cost and plant perturbation, but with smaller OPE and COE improvements than more conventional topping applications. Risk minimization as well as comparative simplicity and convenience, favor CATEC for early market penetration. A program-management plan is proposed. Inputs, characteristics, outputs and capabilities are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMNH33B1648T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMNH33B1648T"><span>Seismo-ionospheric Precursors in the GPS Total Electron Content of the 16 October 1999 Mw7.1 Hector Mine Earthquake</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsai, H.; Su, Y.; Liu, J. G.; Chen, S.; Chen, M.</p> <p>2013-12-01</p> <p>In this paper, temporal and spatial analyses are employed to detect seismo-ionospheric precursors (SIPs) in the ionospheric total electron content (<span class="hlt">TEC</span>) during 16 October 1999 Mw7.1 Hector Mine earthquake. To discriminate anomalies caused by global effects, such as solar radiations, magnetic storms, etc., and local effects, such as earthquake, we cross-examine the GPS <span class="hlt">TECs</span> and their gradients in the eastward and northward directions at epicenter/centers of the Hector Mine area and the other two reference areas at similar magnetic latitudes in Europe and Japan. Temporal variations of the northward <span class="hlt">TEC</span> gradient suggest SIPs most likely appearing day 6-5 before the earthquake. A global search by using the <span class="hlt">TEC</span> of GIM (global ionosphere map) shows that the <span class="hlt">TEC</span> increase and decrease anomalies continuously and specifically appear around the epicenter day 5 before the earthquake.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013IAUS..288..322J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013IAUS..288..322J"><span>Secular variation and fluctuation of GPS Total Electron Content over Antarctica</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jin, Rui; Jin, Shuanggen</p> <p>2013-01-01</p> <p>The total electron content (<span class="hlt">TEC</span>) is an important parameters in the Earth's ionosphere, related to various space weather and solar activities. However, understanding of the complex ionospheric environments is still a challenge due to the lack of direct observations, particularly in the polar areas, e.g., Antarctica. Now the Global Positioning System (GPS) can be used to retrieve total electron content (<span class="hlt">TEC</span>) from dual-frequency observations. The continuous GPS observations in Antarctica provide a good opportunity to investigate ionospheric climatology. In this paper, the long-term variations and fluctuations of <span class="hlt">TEC</span> over Antarctica are investigated from CODE global ionospheric maps (GIM) with a resolution of 2.5°×5° every two hours since 1998. The analysis shows significant seasonal and secular variations in the GPS <span class="hlt">TEC</span>. Furthermore, the effects of <span class="hlt">TEC</span> fluctuations are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24362366','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24362366"><span>Risk-adapted, treosulfan-based therapy with auto- and allo-SCT for relapsed/refractory aggressive NHL: a prospective phase-II trial.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Koenigsmann, M; Casper, J; Kahl, C; Basara, N; Sayer, H G; Behre, G; Theurich, S; Christopeit, M; Mohren, M; Reichle, A; Metzner, B; Ganser, A; Stadler, M; Uharek, L; Balleisen, L; Hinke, A; Hinke, R; Niederwieser, D</p> <p>2014-03-01</p> <p>Since the outcome of relapsed/refractory aggressive non-Hodgkin's lymphoma (NHL) is highly variable, a risk-adapted treatment approach was evaluated. After two cycles of DHAP, patients received high-dose treosulfan/etoposide/carboplatinum (<span class="hlt">TEC</span>) and autologous stem cell rescue. After <span class="hlt">TEC</span>, low-risk patients with late relapse (>1 year after first CR who achieved CR after DHAP received no further treatment. Patients with late relapse who achieved CR or PR only after <span class="hlt">TEC</span> underwent a second cycle of <span class="hlt">TEC</span>. High-risk patients with early relapse/refractory disease received treosulfan/fludarabine followed by allogeneic transplantation. Rituximab was added in patients with B-cell lymphoma (86%). At entry, 36% of all 57 patients had refractory disease, 32% early and 32% late relapse. During DHAP treatment, progression occurred in 32% of patients. Of 33 patients who received <span class="hlt">TEC</span>, 5 received second <span class="hlt">TEC</span> and 15 allogeneic transplantation. Main toxicity after <span class="hlt">TEC</span> was oral mucositis (CTC grades 3 and 4 in 50% and 13%, respectively). In total, 42% patients achieved CR. Median OS was 21.4 months for all patients and 32.6 for those who underwent allogeneic transplantation. International prognostic index (IPI) at study entry was highly discriminative at predicting OS (P<0.0001). Risk-adapted, treosulfan-based therapy with auto- and allo-SCT is feasible. Long-term survival is possible with allogeneic transplantation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26947141','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26947141"><span>Thymus medulla under construction: Time and space oddities.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Alves, Nuno L; Ribeiro, Ana R</p> <p>2016-04-01</p> <p>The development of effective T-cell-based immunotherapies to treat infection, cancer, and autoimmunity should incorporate the ground rules that control differentiation of T cells in the thymus. Within the thymus, thymic epithelial cells (<span class="hlt">TECs</span>) provide microenvironments supportive of the generation and selection of T cells that are responsive to pathogen-derived antigens, and yet tolerant to self-determinants. Defects in <span class="hlt">TEC</span> differentiation cause syndromes that range from immunodeficiency to autoimmunity, which makes the study of <span class="hlt">TECs</span> of fundamental and clinical importance to comprehend how immunity and tolerance are balanced. Critical to tolerance induction are medullary thymic epithelial cells (m<span class="hlt">TECs</span>), which purge autoreactive T cells, or redirect them to a regulatory T-cell lineage. In this issue of the European Journal of Immunology, studies by Baik et al. and Mayer et al. [Eur. J. Immunol. 2016. 46: XXXX-XXXX and 46: XXXX-XXXX]) document novel spatial-temporal singularities in the lineage specification and maintenance of m<span class="hlt">TECs</span>. While Baik et al. define a developmental checkpoint during m<span class="hlt">TEC</span> specification in the embryo, Mayer et al. reveal that the generation and maintenance of the adult m<span class="hlt">TEC</span> compartment is temporally controlled in vivo. The two reports described new developmentally related, but temporally distinct principles that underlie the homeostasis of the thymic medulla across life. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AdSpR..50..211H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AdSpR..50..211H"><span>A nonlinear background removal method for seismo-ionospheric anomaly analysis under a complex solar activity scenario: A case study of the M9.0 Tohoku earthquake</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>He, Liming; Wu, Lixin; Pulinets, Sergey; Liu, Shanjun; Yang, Fan</p> <p>2012-07-01</p> <p>A precise determination of ionospheric total electron content (<span class="hlt">TEC</span>) anomaly variations that are likely associated with large earthquakes as observed by global positioning system (GPS) requires the elimination of the ionospheric effect from irregular solar electromagnetic radiation. In particular, revealing the seismo-ionospheric anomalies when earthquakes occurred during periods of high solar activity is of utmost importance. To overcome this constraint, a multiresolution time series processing technique based on wavelet transform applicable to global ionosphere map (GIM) <span class="hlt">TEC</span> data was used to remove the nonlinear effect from solar radiation for the earthquake that struck Tohoku, Japan, on 11 March, 2011. As a result, it was found that the extracted <span class="hlt">TEC</span> have a good correlation with the measured solar extreme ultraviolet flux in 26-34 nm (EUV26-34) and the 10.7 cm solar radio flux (F10.7). After removing the influence of solar radiation origin in GIM <span class="hlt">TEC</span>, the analysis results show that the <span class="hlt">TEC</span> around the forthcoming epicenter and its conjugate were significantly enhanced in the afternoon period of 8 March 2011, 3 days before the earthquake. The spatial distributions of the <span class="hlt">TEC</span> anomalous and extreme enhancements indicate that the earthquake preparation process had brought with a <span class="hlt">TEC</span> anomaly area of size approximately 1650 and 5700 km in the latitudinal and longitudinal directions, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4597222','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4597222"><span>FSP1+ fibroblast subpopulation is essential for the maintenance and regeneration of medullary thymic epithelial cells</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sun, Lina; Sun, Chenming; Liang, Zhanfeng; Li, Hongran; Chen, Lin; Luo, Haiying; Zhang, Hongmei; Ding, Pengbo; Sun, Xiaoning; Qin, Zhihai; Zhao, Yong</p> <p>2015-01-01</p> <p>Thymic epithelial cells (<span class="hlt">TECs</span>) form a 3-dimentional network supporting thymocyte development and maturation. Besides epithelium and thymocytes, heterogeneous fibroblasts are essential components in maintaining thymic microenvironments. However, thymic fibroblast characteristics, development and function remain to be determined. We herein found that thymic non-hematopoietic CD45-FSP1+ cells represent a unique Fibroblast specific protein 1 (FSP1)—fibroblast-derived cell subset. Deletion of these cells in FSP1-TK transgenic mice caused thymus atrophy due to the loss of <span class="hlt">TECs</span>, especially mature medullary <span class="hlt">TECs</span> (MHCIIhigh, CD80+ and Aire+). In a cyclophosphamide-induced thymus injury and regeneration model, lack of non-hematopoietic CD45-FSP1+ fibroblast subpopulation significantly delayed thymus regeneration. In fact, thymic FSP1+ fibroblasts released more IL-6, FGF7 and FSP1 in the culture medium than their FSP1- counterparts. Further experiments showed that the FSP1 protein could directly enhance the proliferation and maturation of <span class="hlt">TECs</span> in the in vitro culture systems. FSP1 knockout mice had significantly smaller thymus size and less <span class="hlt">TECs</span> than their control. Collectively, our studies reveal that thymic CD45-FSP1+ cells are a subpopulation of fibroblasts, which is crucial for the maintenance and regeneration of <span class="hlt">TECs</span> especially medullary <span class="hlt">TECs</span> through providing IL-6, FGF7 and FSP1. PMID:26445893</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5115952','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5115952"><span>Temperature-assisted solute focusing with sequential trap/release zones in isocratic and gradient capillary liquid chromatography: Simulation and experiment</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Groskreutz, Stephen R.; Weber, Stephen G.</p> <p>2016-01-01</p> <p>In this work we characterize the development of a method to enhance temperature-assisted on-column solute focusing (TASF) called two-stage TASF. A new instrument was built to implement two-stage TASF consisting of a linear array of three independent, electronically controlled Peltier devices (thermoelectric coolers, <span class="hlt">TECs</span>). Samples are loaded onto the chromatographic column with the first two <span class="hlt">TECs</span>, <span class="hlt">TEC</span> A and <span class="hlt">TEC</span> B, cold. In the two-stage TASF approach <span class="hlt">TECs</span> A and B are cooled during injection. <span class="hlt">TEC</span> A is heated following sample loading. At some time following <span class="hlt">TEC</span> A’s temperature rise, <span class="hlt">TEC</span> B’s temperature is increased from the focusing temperature to a temperature matching that of <span class="hlt">TEC</span> A. Injection bands are focused twice on-column, first on the initial <span class="hlt">TEC</span>, e.g. single-stage TASF, then refocused on the second, cold <span class="hlt">TEC</span>. Our goal is to understand the two-stage TASF approach in detail. We have developed a simple yet powerful digital simulation procedure to model the effect of changing temperature in the two focusing zones on retention, band shape and band spreading. The simulation can predict experimental chromatograms resulting from spatial and temporal temperature programs in combination with isocratic and solvent gradient elution. To assess the two-stage TASF method and the accuracy of the simulation well characterized solutes are needed. Thus, retention factors were measured at six temperatures (25–75 °C) at each of twelve mobile phases compositions (0.05–0.60 acetonitrile/water) for homologs of n-alkyl hydroxylbenzoate esters and n-alkyl p-hydroxyphenones. Simulations accurately reflect experimental results in showing that the two-stage approach improves separation quality. For example, two-stage TASF increased sensitivity for a low retention solute by a factor of 2.2 relative to single-stage TASF and 8.8 relative to isothermal conditions using isocratic elution. Gradient elution results for two-stage TASF were more encouraging. Application of two-stage TASF</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27836226','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27836226"><span>Temperature-assisted solute focusing with sequential trap/release zones in isocratic and gradient capillary liquid chromatography: Simulation and experiment.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Groskreutz, Stephen R; Weber, Stephen G</p> <p>2016-11-25</p> <p>In this work we characterize the development of a method to enhance temperature-assisted on-column solute focusing (TASF) called two-stage TASF. A new instrument was built to implement two-stage TASF consisting of a linear array of three independent, electronically controlled Peltier devices (thermoelectric coolers, <span class="hlt">TECs</span>). Samples are loaded onto the chromatographic column with the first two <span class="hlt">TECs</span>, <span class="hlt">TEC</span> A and <span class="hlt">TEC</span> B, cold. In the two-stage TASF approach <span class="hlt">TECs</span> A and B are cooled during injection. <span class="hlt">TEC</span> A is heated following sample loading. At some time following <span class="hlt">TEC</span> A's temperature rise, <span class="hlt">TEC</span> B's temperature is increased from the focusing temperature to a temperature matching that of <span class="hlt">TEC</span> A. Injection bands are focused twice on-column, first on the initial <span class="hlt">TEC</span>, e.g. single-stage TASF, then refocused on the second, cold <span class="hlt">TEC</span>. Our goal is to understand the two-stage TASF approach in detail. We have developed a simple yet powerful digital simulation procedure to model the effect of changing temperature in the two focusing zones on retention, band shape and band spreading. The simulation can predict experimental chromatograms resulting from spatial and temporal temperature programs in combination with isocratic and solvent gradient elution. To assess the two-stage TASF method and the accuracy of the simulation well characterized solutes are needed. Thus, retention factors were measured at six temperatures (25-75°C) at each of twelve mobile phases compositions (0.05-0.60 acetonitrile/water) for homologs of n-alkyl hydroxylbenzoate esters and n-alkyl p-hydroxyphenones. Simulations accurately reflect experimental results in showing that the two-stage approach improves separation quality. For example, two-stage TASF increased sensitivity for a low retention solute by a factor of 2.2 relative to single-stage TASF and 8.8 relative to isothermal conditions using isocratic elution. Gradient elution results for two-stage TASF were more encouraging. Application of two-stage TASF</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4649202','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4649202"><span>Comparison of Borate Bioactive Glass and Calcium Sulfate as Implants for the Local Delivery of Teicoplanin in the Treatment of Methicillin-Resistant Staphylococcus aureus-Induced Osteomyelitis in a Rabbit Model</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Jia, Wei-Tao; Fu, Qiang; Huang, Wen-Hai</p> <p>2015-01-01</p> <p>There is growing interest in biomaterials that can cure bone infection and also regenerate bone. In this study, two groups of implants composed of 10% (wt/wt) teicoplanin (<span class="hlt">TEC</span>)-loaded borate bioactive glass (designated TBG) or calcium sulfate (TCS) were created and evaluated for their ability to release <span class="hlt">TEC</span> in vitro and to cure methicillin-resistant Staphylococcus aureus (MRSA)-induced osteomyelitis in a rabbit model. When immersed in phosphate-buffered saline (PBS), both groups of implants provided a sustained release of <span class="hlt">TEC</span> at a therapeutic level for up to 3 to 4 weeks while they were gradually degraded and converted to hydroxyapatite. The TBG implants showed a longer duration of <span class="hlt">TEC</span> release and better retention of strength as a function of immersion time in PBS. Infected rabbit tibiae were treated by debridement, followed by implantation of TBG or TCS pellets or intravenous injection with <span class="hlt">TEC</span>, or were left untreated. Evaluation at 6 weeks postimplantation showed that the animals implanted with TBG or TCS pellets had significantly lower radiological and histological scores, lower rates of MRSA-positive cultures, and lower bacterial loads than those preoperatively and those of animals treated intravenously. The level of bone regeneration was also higher in the defects treated with the TBG pellets. The results showed that local <span class="hlt">TEC</span> delivery was more effective than intravenous administration for the treatment of MRSA-induced osteomyelitis. Borate glass has the advantages of better mechanical strength, more desirable kinetics of release of <span class="hlt">TEC</span>, and a higher osteogenic capacity and thus could be an effective alternative to calcium sulfate for local delivery of <span class="hlt">TEC</span>. PMID:26416858</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26416858','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26416858"><span>Comparison of Borate Bioactive Glass and Calcium Sulfate as Implants for the Local Delivery of Teicoplanin in the Treatment of Methicillin-Resistant Staphylococcus aureus-Induced Osteomyelitis in a Rabbit Model.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jia, Wei-Tao; Fu, Qiang; Huang, Wen-Hai; Zhang, Chang-Qing; Rahaman, Mohamed N</p> <p>2015-12-01</p> <p>There is growing interest in biomaterials that can cure bone infection and also regenerate bone. In this study, two groups of implants composed of 10% (wt/wt) teicoplanin (<span class="hlt">TEC</span>)-loaded borate bioactive glass (designated TBG) or calcium sulfate (TCS) were created and evaluated for their ability to release <span class="hlt">TEC</span> in vitro and to cure methicillin-resistant Staphylococcus aureus (MRSA)-induced osteomyelitis in a rabbit model. When immersed in phosphate-buffered saline (PBS), both groups of implants provided a sustained release of <span class="hlt">TEC</span> at a therapeutic level for up to 3 to 4 weeks while they were gradually degraded and converted to hydroxyapatite. The TBG implants showed a longer duration of <span class="hlt">TEC</span> release and better retention of strength as a function of immersion time in PBS. Infected rabbit tibiae were treated by debridement, followed by implantation of TBG or TCS pellets or intravenous injection with <span class="hlt">TEC</span>, or were left untreated. Evaluation at 6 weeks postimplantation showed that the animals implanted with TBG or TCS pellets had significantly lower radiological and histological scores, lower rates of MRSA-positive cultures, and lower bacterial loads than those preoperatively and those of animals treated intravenously. The level of bone regeneration was also higher in the defects treated with the TBG pellets. The results showed that local <span class="hlt">TEC</span> delivery was more effective than intravenous administration for the treatment of MRSA-induced osteomyelitis. Borate glass has the advantages of better mechanical strength, more desirable kinetics of release of <span class="hlt">TEC</span>, and a higher osteogenic capacity and thus could be an effective alternative to calcium sulfate for local delivery of <span class="hlt">TEC</span>. Copyright © 2015, American Society for Microbiology. All Rights Reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.P13D..08P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.P13D..08P"><span>Vertical and Lateral Electron Content in the Martian Ionosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Paetzold, M. P.; Peter, K.; Bird, M. K.; Häusler, B.; Tellmann, S.</p> <p>2016-12-01</p> <p>The radio-science experiment MaRS (Mars Express Radio Science) on the Mars Express spacecraft sounds the neutral atmosphere and ionosphere of Mars since 2004. Approximately 800 vertical profiles of the ionospheric electron density have been acquired until today. The vertical electron content (<span class="hlt">TEC</span>) is easily computed from the vertical electron density profile by integrating along the altitude. The <span class="hlt">TEC</span> is typically a fraction of a <span class="hlt">TEC</span> unit (1E16 m^-2) and depends on the solar zenith angle. The magnitude of the <span class="hlt">TEC</span> is however fully dominated by the electron density contained in the main layer M2. The contributions by the M1 layer below M2 or the topside is marginal. MaRS is using two radio frequencies for the sounding of the ionosphere. The directly observed differential Doppler from the two received frequencies is a measure of the lateral electron content that means along the ray path and perpendicular to the vertical electron density profile. Combining both the vertical electron density profile, the vertical <span class="hlt">TEC</span> and the directly observed lateral <span class="hlt">TEC</span> describes the lateral electron density distribution in the ionosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28389777','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28389777"><span>Contribution of tumor endothelial cells to drug resistance: anti-angiogenic tyrosine kinase inhibitors act as p-glycoprotein antagonists.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bani, MariaRosa; Decio, Alessandra; Giavazzi, Raffaella; Ghilardi, Carmen</p> <p>2017-05-01</p> <p>Tumor endothelial cells (<span class="hlt">TEC</span>) differ from the normal counterpart, in both gene expression and functionality. <span class="hlt">TEC</span> may acquire drug resistance, a characteristic that is maintained in vitro. There is evidence that <span class="hlt">TEC</span> are more resistant to chemotherapeutic drugs, substrates of ATP-binding cassette (ABC) transporters. <span class="hlt">TEC</span> express p-glycoprotein (encoded by ABCB1), while no difference in other ABC transporters was revealed compared to normal endothelia. A class of tyrosine kinase inhibitors (TKI), used as angiostatic compounds, interferes with the ATPase activity of p-glycoprotein, thus impairing its functionality. The exposure of ovarian adenocarcinoma <span class="hlt">TEC</span> to the TKIs sunitinib or sorafenib was found to abrogate resistance (proliferation and motility) to doxorubicin and paclitaxel in vitro, increasing intracellular drug accumulation. A similar effect has been reported by the p-glycoprotein inhibitor verapamil. No beneficial effect was observed in combination with cytotoxic drugs that are not p-glycoprotein substrates. The current paper reviews the mechanisms of <span class="hlt">TEC</span> chemoresistance and shows the role of p-glycoprotein in mediating such resistance. Inhibition of p-glycoprotein by anti-angiogenic TKI might contribute to the beneficial effect of these small molecules, when combined with chemotherapy, in counteracting acquired drug resistance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JPS...178...48H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JPS...178...48H"><span>A novel binary Pt 3Te x/C nanocatalyst for ethanol electro-oxidation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huang, Meihua; Wang, Fei; Li, Lirong; Guo, Yonglang</p> <p></p> <p>The Pt 3Te x/C nanocatalyst was prepared and its catalytic performance for ethanol oxidation was investigated for the first time. The Pt 3<span class="hlt">Te/C</span> nanoparticles were characterized by an X-ray diffractometer (XRD), transmission electron microscope (TEM) and energy dispersive X-ray spectroscopy equipped with TEM (TEM-EDX). The Pt 3<span class="hlt">Te/C</span> catalyst has a typical fcc structure of platinum alloys with the presence of Te. Its particle size is about 2.8 nm. Among the synthesized catalysts with different atomic ratios, the Pt 3<span class="hlt">Te/C</span> catalyst has the highest anodic peak current density. The cyclic voltammograms (CV) show that the anodic peak current density for the Pt 3<span class="hlt">Te/C</span>, commercial PtRu/C and Pt/C catalysts reaches 1002, 832 and 533 A g -1, respectively. On the current-time curve, the anodic current on the Pt 3<span class="hlt">Te/C</span> catalyst was higher than those for the catalysts reported. So, these findings show that the Pt 3<span class="hlt">Te/C</span> catalyst has uniform nanoparticles and the best activity among the synthesized catalysts, and it is better than commercial PtRu/C and Pt/C catalysts for ethanol oxidation at room temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1817522H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1817522H"><span>Assessment of Ionospheric Anomaly Prior to the Large Earthquake: 2D and 3D Analysis in Space and Time for the 2011 Tohoku Earthquake (Mw9.0)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hattori, Katsumi; Hirooka, Shinji; Han, Peng</p> <p>2016-04-01</p> <p>The ionospheric anomalies possibly associated with large earthquakes have been reported by many researchers. In this paper, Total Electron Content (<span class="hlt">TEC</span>) and tomography analyses have been applied to investigate the spatial and temporal distributions of ionospheric electron density prior to the 2011 Off the Pacific Coast of Tohoku earthquake (Mw9.0). Results show significant <span class="hlt">TEC</span> enhancements and an interesting three dimensional structure prior to the main shock. As for temporal <span class="hlt">TEC</span> changes, the <span class="hlt">TEC</span> value increases 3-4 days before the earthquake remarkably, when the geomagnetic condition was relatively quiet. In addition, the abnormal <span class="hlt">TEC</span> enhancement area in space was stalled above Japan during the period. Tomographic results show that three dimensional distribution of electron density decreases around 250 km altitude above the epicenter (peak is located just the east-region of the epicenter) and increases the mostly entire region between 300 and 400 km.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26973329','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26973329"><span>Synovial mesenchymal stem cells from osteo- or rheumatoid arthritis joints exhibit good potential for cartilage repair using a scaffold-free tissue engineering approach.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Koizumi, K; Ebina, K; Hart, D A; Hirao, M; Noguchi, T; Sugita, N; Yasui, Y; Chijimatsu, R; Yoshikawa, H; Nakamura, N</p> <p>2016-08-01</p> <p>To assess whether synovial mesenchymal stem cells (SMSCs) from patients with osteoarthritis (OA) or rheumatoid arthritis (RA) can be used as an alternative cell source for cartilage repair using allogenic tissue engineered construct (<span class="hlt">TEC</span>). Twenty-five patients (17 female, average age 61.8 years) were divided according to their pathology (control trauma group; N = 6, OA group; N = 6) and RA patients were subdivided into two groups to evaluate the impact of biologics in accordance with whether treated with biologics [Bio(+)RA; N = 7] or not [Bio(-)RA; N = 6]. We compared the following characteristics among these groups: (1) The cell proliferation capacity of SMSCs; (2) The influence of passage number on features of SMSCs; (3) The weight and volume of <span class="hlt">TEC</span> from the same number of SMSCs; (4) Inflammatory cytokine gene expressions levels of <span class="hlt">TEC</span>; (5) The chondrogenic potential of <span class="hlt">TEC</span>; and (6) Osteochondral repair using <span class="hlt">TEC</span> in athymic nude rats. SMSCs from the four groups exhibited equivalent features in the above evaluation items. In in vivo studies, the <span class="hlt">TEC</span>-treated repair tissues for all groups exhibited significantly better outcomes than those for the untreated group and no significant differences among the four <span class="hlt">TEC</span> groups. SMSCs from OA or RA patients are no less appropriate for repairing cartilage than those from trauma patients and thus, may be an effective source for allogenic cell-based cartilage repair. Copyright © 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012Ap%26SS.341..251L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012Ap%26SS.341..251L"><span>Ionospheric total electron content seismo-perturbation after Japan's March 11, 2011, M=9.0 Tohoku earthquake under a geomagnetic storm; a nonlinear principal component analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lin, Jyh-Woei</p> <p>2012-10-01</p> <p>Nonlinear principal component analysis (NLPCA) is implemented to analyze the spatial pattern of total electron content (<span class="hlt">TEC</span>) anomalies 3 hours after Japan's Tohoku earthquake that occurred at 05:46:23 on 11 March, 2011 (UTC) ( M w =9). A geomagnetic storm was in progress at the time of the earthquake. NLPCA and <span class="hlt">TEC</span> data processing were conducted on the global ionospheric map (GIM) for the time between 08:30 to 09:30 UTC, about 3 hours after this devastating earthquake and ensuing tsunami. Analysis results show stark earthquake-associated <span class="hlt">TEC</span> anomalies that are widespread, and appear to have been induced by two acoustic gravity waves due to strong shaking (vertical acoustic wave) and the generation of the tsunami (horizontal Rayleigh mode gravity wave). The <span class="hlt">TEC</span> anomalies roughly fit the initial mainshock and movement of the tsunami. Observation of the earthquake-associated <span class="hlt">TEC</span> anomalies does not appear to be affected by a contemporaneous geomagnetic storm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E.644G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E.644G"><span>Earthquake Related Variation of Total Electron Content in Ionosphere over Chinese Mainland Derived from Observations of a Nationwide GNSS Network</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gan, Weijun</p> <p>2016-07-01</p> <p>Crustal Movement Observation Network of China (CMONOC) is a key national scientific infrastructure project carried out during 1997-2012 with 2 phases. The network is composed of 260 continuously observed GNSS stations (CORS) and 2081 campaign mode GNSS stations, with the main purpose to monitor the crustal movement, perceptible water vapor (PWV), total electron content (<span class="hlt">TEC</span>), and many other tectonic and environmental elements around mainland China, by mainly using the Global Navigation Satellite System (GNSS) technology. Here, based on the GNSS data of 260 CORS of COMNOC for about 5 years, we investigated the characteristics of <span class="hlt">TEC</span> in ionosphere over Chinese Mainland and discussed if there was any abnormal change of <span class="hlt">TEC</span> before and after a big earthquake. our preliminary results show that it is hard to see any convincing precursor of <span class="hlt">TEC</span> before a big earthquake. However, the huge energy released by a big earthquake can obviously disturb the <span class="hlt">TEC</span> over meizoseismal area.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AdSpR..60.1958K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AdSpR..60.1958K"><span>Ionospheric responses during equinox and solstice periods over Turkey</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karatay, Secil; Cinar, Ali; Arikan, Feza</p> <p>2017-11-01</p> <p>Ionospheric electron density is the determining variable for investigation of the spatial and temporal variations in the ionosphere. Total Electron Content (<span class="hlt">TEC</span>) is the integral of the electron density along a ray path that indicates the total variability through the ionosphere. Global Positioning System (GPS) recordings can be utilized to estimate the <span class="hlt">TEC</span>, thus GPS proves itself as a useful tool in monitoring the total variability of electron distribution within the ionosphere. This study focuses on the analysis of the variations of ionosphere over Turkey that can be grouped into anomalies during equinox and solstice periods using <span class="hlt">TEC</span> estimates obtained by a regional GPS network. It is observed that noon time depletions in <span class="hlt">TEC</span> distributions predominantly occur in winter for minimum Sun Spots Numbers (SSN) in the central regions of Turkey which also exhibit high variability due to midlatitude winter anomaly. <span class="hlt">TEC</span> values and ionospheric variations at solstice periods demonstrate significant enhancements compared to those at equinox periods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..12211794C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..12211794C"><span>The First Use of Coordinated Ionospheric Radio and Optical Observations Over Italy: Convergence of High-and Low-Latitude Storm-Induced Effects</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cesaroni, C.; Alfonsi, L.; Pezzopane, M.; Martinis, C.; Baumgardner, J.; Wroten, J.; Mendillo, M.; Musicò, E.; Lazzarin, M.; Umbriaco, G.</p> <p>2017-11-01</p> <p>Ionospheric storm effects at midlatitudes were analyzed using different ground-based instruments distributed in Italy during the 13-15 November 2012 geomagnetic storm. These included an all-sky imager (ASI) in Asiago (45.8°N, 11.5°E), a network of dual-frequeny Global Navigation Satellite Systems receivers (Rete Integrata Nazionale GPS network), and ionosondes in Rome (41.8°N, 12.5°E) and San Vito (40.6°N, 17.8°E). GPS measurements showed an unusual enhancement of total electron content (<span class="hlt">TEC</span>) in southern Italy, during the nights of 14 and 15 November. The ASI observed colocated enhancements of 630 nm airglow at the same time, as did variations in NmF2 measured by the ionosondes. Moreover, wave-like perturbations were identified propagating from the north. The Ensemble Empirical Mode Decomposition, applied to <span class="hlt">TEC</span> values revealed the presence of traveling ionospheric disturbances (TIDs) propagating southward between 01:30 UT and 03:00 UT on 15 November. These TIDs were characterized by weak <span class="hlt">TEC</span> oscillations ( ±0.5 <span class="hlt">TEC</span> unit), period of 45 min, and velocity of 500 m/s typical of large-scale TIDs. Optical images showed enhanced airglow entering the field of view of the ASI from the N-NE at 02:00 UT and propagating to the S-SW, reaching the region covered by the GPS stations after 03:00 UT, when <span class="hlt">TEC</span> fluctuations are very small ( ±0.2 <span class="hlt">TEC</span> unit). The enhancement of <span class="hlt">TEC</span> and airglow observed in southern Italy could be a consequence of a poleward expansion of the northern crest of the equatorial ionization anomaly. The enhanced airglow propagating from the north and the <span class="hlt">TEC</span> waves resulted from energy injected at auroral latitudes as confirmed by magnetometer observations in Scandinavia.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SunGe...9...63L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SunGe...9...63L"><span>Case study of ISWI in Vietnam: A comparison of ionospheric parameters observed over Ho Chi Minh with IRI predictions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lan, Hoang Thai; Tam, Dao Ngoc Hanh</p> <p>2014-01-01</p> <p>For the contribution of Vietnam to ISWI activities, there are 3 GPS receivers, 3 Ionosondes, 1 AWESOME and 1 MAGDAS operating in Vietnam. With a special geographical position stretching from the north tropic to the magnetic equator, Vietnam is an interesting area to supplement the data for the Global Space Weather Model. The Ionosphere is an important indicator of Space Weather and the International Reference Ionosphere (IRI) model has become widely accepted. The first task of ionospheric science in a new location is often comparing the observed data with IRI. This paper presents the results of comparisons of the foF2 and <span class="hlt">TEC</span> observed over Ho Chi Minh City (10.51 N, 106.33 E) with the values calculated according to the IRI-2007 in order to evaluate the applicability of the model in forecasting for the equatorial region of Vietnam. We compare the critical frequency of layer F (foF2) and Total Electron Content (<span class="hlt">TEC</span>) values for two phases of solar activity. The results show very good diurnal correlations between the observed foF2 and <span class="hlt">TEC</span> with IRI values in the decreasing solar activity period 2003 ± 2006 (the deviation < 15%). In the increasing period 2009 ± 2012, good correlation was in the morning time before the foF2 peak at about 10 LT, with a deviation about 10% (except 2012). However, after 10 LT, the IRI-foF2 values rose up and the deviations were about 25% to 30%, especially during evening. In the years with low solar activity (SSN < 40), the IRI-foF2 are almost always higher than the observed foF2 data and vice versa for the years with SSN > 40. This is a note for correction IRI model applying for Vietnam. The comparison of the <span class="hlt">TEC</span> shows that the correlation between GPS-<span class="hlt">TEC</span> and IRI-<span class="hlt">TEC</span> generally was good with coefficients k > 0.8 and R > 0.9 for the period 2006 - 2010. The worst relationship were March, April, September, October, November and December 2011, corresponding to periods when the <span class="hlt">TEC</span> gradients are highest. The phenomenon of decline in the <span class="hlt">TEC</span> at</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JEMat..47.3282S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JEMat..47.3282S"><span>Optimal Integration of Cascade Thermoelectric Cooler into Electronic Housing: Experimental Approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Semeniuk, V.; Protsenko, D.</p> <p>2018-06-01</p> <p>The problem of the optimal integration of thermoelectrically cooled optoelectronic components into an electronic housing is studied with the emphasis on practical implementation. The lines of 2-stage and 3-stage thermoelectric coolers (<span class="hlt">TECs</span>) compatible with TO8 housing have been developed, and their parameters are measured in a wide range of heat sink temperatures. The <span class="hlt">TECs</span> are optimized to receive a temperature difference of 100-110 K under a heat load from 70 mW to 100 mW with minimal power consumption. To fit into a standard housing interior, all the <span class="hlt">TECs</span> have the same overall dimensions, regardless of the number of stages. Details of the <span class="hlt">TEC</span> configurations and their performance characteristics are presented and discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018IJT....39...40K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018IJT....39...40K"><span>Measurement of the Thermal Expansion Coefficient for Ultra-High Temperatures up to 3000 K</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kompan, T. A.; Kondratiev, S. V.; Korenev, A. S.; Puhov, N. F.; Inochkin, F. M.; Kruglov, S. K.; Bronshtein, I. G.</p> <p>2018-03-01</p> <p>The paper is devoted to a new high-temperature dilatometer, a part of the State Primary Standard of the thermal expansion coefficient (<span class="hlt">TEC</span>) unit. The dilatometer is designed for investigation and certification of materials for <span class="hlt">TEC</span> standards in the range of extremely high temperatures. The critical review of existing methods of <span class="hlt">TEC</span> measurements is given. Also, the design, principles of operation and metrological parameters of the new device are described. The main attention is paid to the system of machine vision that allows accurate measurement of elongation at high temperatures. The results of <span class="hlt">TEC</span> measurements for graphite GIP-4, single crystal Al2O3, and some other materials are also presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JEMat.tmp.2548S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JEMat.tmp.2548S"><span>Optimal Integration of Cascade Thermoelectric Cooler into Electronic Housing: Experimental Approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Semeniuk, V.; Protsenko, D.</p> <p>2018-03-01</p> <p>The problem of the optimal integration of thermoelectrically cooled optoelectronic components into an electronic housing is studied with the emphasis on practical implementation. The lines of 2-stage and 3-stage thermoelectric coolers (<span class="hlt">TECs</span>) compatible with TO8 housing have been developed, and their parameters are measured in a wide range of heat sink temperatures. The <span class="hlt">TECs</span> are optimized to receive a temperature difference of 100-110 K under a heat load from 70 mW to 100 mW with minimal power consumption. To fit into a standard housing interior, all the <span class="hlt">TECs</span> have the same overall dimensions, regardless of the number of stages. Details of the <span class="hlt">TEC</span> configurations and their performance characteristics are presented and discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.5437U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.5437U"><span>Investigation of the Effects of Solar and Geomagnetic Changes on the Total Electron Content: Mid-Latitude Region</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ulukavak, Mustafa; Yalcinkaya, Mualla</p> <p>2016-04-01</p> <p>The Global Positioning System (GPS) is used as an important tool for ionosphere monitoring and obtaining the Total Electron Content (<span class="hlt">TEC</span>). 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-<span class="hlt">TEC</span> 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-<span class="hlt">TEC</span> variations were determined for the quiet periods of the solar and geomagnetic activities. GPS-<span class="hlt">TEC</span> 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-<span class="hlt">TEC</span> variations. The investigations revealed that it is possible to use the GPS-<span class="hlt">TEC</span> data for monitoring the ionospheric disturbances.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930071162&hterms=ionospheric+tomography&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dionospheric%2Btomography','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930071162&hterms=ionospheric+tomography&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dionospheric%2Btomography"><span>Analysis of rocket beacon transmissions for computerized reconstruction of ionospheric densities</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bernhardt, P. A.; Huba, J. D.; Chaturvedi, P. K.; Fulford, J. A.; Forsyth, P. A.; Anderson, D. N.; Zalesak, S. T.</p> <p>1993-01-01</p> <p>Three methods are described to obtain ionospheric electron densities from transionospheric, rocket-beacon <span class="hlt">TEC</span> data. First, when the line-of-sight from a ground receiver to the rocket beacon is tangent to the flight trajectory, the electron concentration can be obtained by differentiating the <span class="hlt">TEC</span> with respect to the distance to the rocket. A similar method may be used to obtain the electron-density profile if the layer is horizontally stratified. Second, <span class="hlt">TEC</span> data obtained during chemical release experiments may be interpreted with the aid of physical models of the disturbed ionosphere to yield spatial maps of the modified regions. Third, computerized tomography (CT) can be used to analyze <span class="hlt">TEC</span> data obtained along a chain of ground-based receivers aligned along the plane of the rocket trajectory. CT analysis of <span class="hlt">TEC</span> data is used to reconstruct a 2D image of a simulated equatorial plume. <span class="hlt">TEC</span> data is computed for a linear chain of nine receivers with adjacent spacings of either 100 or 200 km. The simulation data are analyzed to provide an F region reconstruction on a grid with 15 x 15 km pixels. Ionospheric rocket tomography may also be applied to rocket-assisted measurements of amplitude and phase scintillations and airglow intensities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29605473','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29605473"><span>Real-Time Three-Dimensional Echocardiography of the Left Ventricle-Pediatric Percentiles and Head-to-Head Comparison of Different Contour-Finding Algorithms: A Multicenter Study.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Krell, Kristina; Laser, Kai Thorsten; Dalla-Pozza, Robert; Winkler, Christian; Hildebrandt, Ursula; Kececioglu, Deniz; Breuer, Johannes; Herberg, Ulrike</p> <p>2018-03-28</p> <p>Real-time three-dimensional echocardiography (RT3DE) is a promising method for accurate assessment of left ventricular (LV) volumes and function, however, pediatric reference values are scarce. The aim of the study was to establish pediatric percentiles in a large population and to compare the inherent influence of different evaluation software on the resulting measurements. In a multicenter prospective-design study, 497 healthy children (ages 1 day to 219 months) underwent RT3DE imaging of the LV (ie33, Philips, Andover, MA). Volume analysis was performed using QLab 9.0 (Philips) and Tom<span class="hlt">Tec</span> 4DLV2.7 (vendor-independent; testing high (Tom<span class="hlt">Tec</span> 75 ) and low (Tom<span class="hlt">Tec</span> 30 ) contour-finding activity). Reference percentiles were computed using Cole's LMS method. In 22 subjects, cardiovascular magnetic resonance imaging (CMR) was used as the reference. A total of 370/497 (74.4%) of the subjects provided adequate data sets. LV volumes had a significant association with age, body size, and gender; therefore, sex-specific percentiles were indexed to body surface area. Intra- and interobserver variability for both workstations was good (relative bias ± SD for end-diastolic volume [EDV] in %: intraobserver: QLab = -0.8 ± 2.4; Tom<span class="hlt">Tec</span> 30  = -0.7 ± 7.2; Tom<span class="hlt">Tec</span> 75  = -1.9 ± 6.7; interobserver: QLab = 2.4 ± 7.5; Tom<span class="hlt">Tec</span> 30  = 1.2 ± 5.1; Tom<span class="hlt">Tec</span> 75  = 1.3 ± 4.5). Intervendor agreement between QLab and Tom<span class="hlt">Tec</span> 30 showed larger bias and wider limits of agreement (bias: QLab vs Tom<span class="hlt">Tec</span> 30 : end-systolic volume [ESV] = 0.8% ± 23.6%; EDV = -2.2% ± 17.0%) with notable individual differences in small children. QLab and Tom<span class="hlt">Tec</span> underestimated CMR values, with the highest agreement between CMR and QLab. RT3DE allows reproducible noninvasive assessment of LV volumes and function. However, intertechnique variability is relevant. Therefore, our software-specific percentiles, based on a large pediatric population, serve as a reference for both commonly used</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=408067','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=408067"><span>Interphase ribosomal RNA cistron staining in thyroid epithelial cells in Grave's disease, Hashimoto's thyroiditis and benign and malignant tumours of the thyroid gland</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Mamaev, N N; Grynyeva, E N; Blagosklonnaya, Y V</p> <p>1996-01-01</p> <p>Aim—To evaluate the expression of ribosomal cistrons in human thyroid epithelial cells (<span class="hlt">TECs</span>) of patients with Grave's disease, Hashimoto's thyroiditis and benign and malignant tumours of the thyroid gland. Methods—<span class="hlt">TEC</span> nucleoli were investigated in fine needle biopsy specimens from 10 controls, 39 patients with Grave's disease, 15 with Hashimoto's thyroiditis, 56 with benign, and 15 with malignant tumours of the thyroid. A one step silver staining method was applied. In most cases serum concentrations of thyroxine and triiodothyronine as well as goitre size were determined. In every case 100 <span class="hlt">TECs</span> were evaluated for the mean numbers of nucleoli and for the average number of argyrophilic nucleolar organiser regions (AgNORs) per nucleus. Results—NORs were activated in all patients, but not in controls. The numbers of AgNORs in patients with Grave's disease were closely correlated with thyroxine or triiodothyronine, or both, concentrations and with the size of the thyroid. In patients with Hashimoto's thyroiditis about 30% of <span class="hlt">TECs</span> nucleoli did not contain AgNORs, whereas others were heavily impregnated with silver. Compared with controls and benign tumours, the nucleoli of carcinomatous <span class="hlt">TECs</span> were larger and irregular in shape. The mean number of AgNORs per nucleus in malignant cells was higher than that in their benign counterparts. Conclusions—The mechanism by which NORs are activated in <span class="hlt">TECs</span> varies depending on the type of lesion. The higher AgNOR score in <span class="hlt">TECs</span> from malignant tumours can be used to distinguish them from their benign counterparts. Images PMID:16696083</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017STP.....3d..83I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017STP.....3d..83I"><span>Complex analysis of the ionospheric response to operation of ``Progress'' cargo spacecraft according to the data of GNSS receivers in Baikal region</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ishin, Artem; Voeykov, Sergey; Perevalova, Natalia; Khakhinov, Vitaliy</p> <p>2017-12-01</p> <p>As a part of the Plasma-Progress and Radar-Progress space experiments conducted from 2006 to 2014, effects of the Progress spacecraft engines on the ionosphere have been studied using data from Global Navigation Satellite System (GNSS) receivers. 72 experiments have been carried out. All these experiments were based on data from the International GNSS Service (IGS) to record ionospheric plasma irregularities caused by engine operation. 35 experiments used data from the ISTP SB RAS network SibNet. The analysis of the spatio-temporal structure of total electron content (<span class="hlt">TEC</span>) variations has shown that the problem of identifying the <span class="hlt">TEC</span> response to engine operation is complicated by a number of factors: 1) the engine effect on ionospheric plasma is strongly localized in space and has a relatively low intensity; 2) a small number of satellite-receiver radio rays due to the limited number of GNSS stations, particularly before 2013; 3) a potential <span class="hlt">TEC</span> response is masked with background ionospheric disturbances of various intensities. However, <span class="hlt">TEC</span> responses are identified with certainty when a satellite-receiver radio ray crosses a disturbed region within minutes after the impact. <span class="hlt">TEC</span> responses have been registered in 7 experiments (10 % of cases). The amplitude of ionospheric response (0.3-0.16 TECU) exceeded the background <span class="hlt">TEC</span> variations (~0.25 TECU) several times. The <span class="hlt">TEC</span> data indicate that the ionospheric irregularity lifetime is from 4 to 10 minutes. According to the estimates we made, the transverse size of irregularities is from 12 to 30 km.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1916551H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1916551H"><span>Ionosphere monitoring and forecast activities within the IAG working group "Ionosphere Prediction"</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hoque, Mainul; Garcia-Rigo, Alberto; Erdogan, Eren; Cueto Santamaría, Marta; Jakowski, Norbert; Berdermann, Jens; Hernandez-Pajares, Manuel; Schmidt, Michael; Wilken, Volker</p> <p>2017-04-01</p> <p>Ionospheric disturbances can affect technologies in space and on Earth disrupting satellite and airline operations, communications networks, navigation systems. As the world becomes ever more dependent on these technologies, ionospheric disturbances as part of space weather pose an increasing risk to the economic vitality and national security. Therefore, having the knowledge of ionospheric state in advance during space weather events is becoming more and more important. To promote scientific cooperation we recently formed a Working Group (WG) called "Ionosphere Predictions" within the International Association of Geodesy (IAG) under Sub-Commission 4.3 "Atmosphere Remote Sensing" of the Commission 4 "Positioning and Applications". The general objective of the WG is to promote the development of ionosphere prediction algorithm/models based on the dependence of ionospheric characteristics on solar and magnetic conditions combining data from different sensors to improve the spatial and temporal resolution and sensitivity taking advantage of different sounding geometries and latency. Our presented work enables the possibility to compare total electron content (<span class="hlt">TEC</span>) prediction approaches/results from different centers contributing to this WG such as German Aerospace Center (DLR), Universitat Politècnica de Catalunya (UPC), Technische Universität München (TUM) and GMV. DLR developed a model-assisted <span class="hlt">TEC</span> forecast algorithm taking benefit from actual trends of the <span class="hlt">TEC</span> behavior at each grid point. Since during perturbations, characterized by large <span class="hlt">TEC</span> fluctuations or ionization fronts, this approach may fail, the trend information is merged with the current background model which provides a stable climatological <span class="hlt">TEC</span> behavior. The presented solution is a first step to regularly provide forecasted <span class="hlt">TEC</span> services via SWACI/IMPC by DLR. UPC forecast model is based on applying linear regression to a temporal window of <span class="hlt">TEC</span> maps in the Discrete Cosine Transform (DCT) domain</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011MNRAS.415.3831A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011MNRAS.415.3831A"><span>Az<span class="hlt">TEC</span> millimetre survey of the COSMOS field - III. Source catalogue over 0.72 deg2 and plausible boosting by large-scale structure</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aretxaga, I.; Wilson, G. W.; Aguilar, E.; Alberts, S.; Scott, K. S.; Scoville, N.; Yun, M. S.; Austermann, J.; Downes, T. P.; Ezawa, H.; Hatsukade, B.; Hughes, D. H.; Kawabe, R.; Kohno, K.; Oshima, T.; Perera, T. A.; Tamura, Y.; Zeballos, M.</p> <p>2011-08-01</p> <p>We present a 0.72 deg2 contiguous 1.1-mm survey in the central area of the Cosmological Evolution Survey field carried out to a 1σ≈ 1.26 mJy beam-1 depth with the Az<span class="hlt">TEC</span> camera mounted on the 10-m Atacama Submillimeter Telescope Experiment. We have uncovered 189 candidate sources at a signal-to-noise ratio (S/N) ≥ 3.5, out of which 129, with S/N ≥ 4, can be considered to have little chance of being spurious (≲2 per cent). We present the number counts derived with this survey, which show a significant excess of sources when compared to the number counts derived from the ˜0.5 deg2 area sampled at similar depths in the Submillimetre Common-User Bolometer Array (SCUBA) HAlf Degree Extragalactic Survey (SHADES). They are, however, consistent with those derived from fields that were considered too small to characterize the overall blank-field population. We identify differences to be more significant in the S1.1mm≳ 5 mJy regime, and demonstrate that these excesses in number counts are related to the areas where galaxies at redshifts z≲ 1.1 are more densely clustered. The positions of optical-infrared galaxies in the redshift interval 0.6 ≲z≲ 0.75 are the ones that show the strongest correlation with the positions of the 1.1-mm bright population (S1.1mm≳ 5 mJy), a result which does not depend exclusively on the presence of rich clusters within the survey sampled area. The most likely explanation for the observed excess in number counts at 1.1-mm is galaxy-galaxy and galaxy-group lensing at moderate amplification levels, which increases in amplitude as one samples larger and larger flux densities. This effect should also be detectable in other high-redshift populations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSA13B2354D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSA13B2354D"><span>A simplified traveling ionospheric disturbance (TID) specification model based on TID Detector Built In Texas (TIDDBIT) and GPS total electron content (<span class="hlt">TEC</span>) measurements.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Duly, T. M.; Crowley, G.; Azeem, I.</p> <p>2015-12-01</p> <p>There is currently a great deal of interest in Traveling Ionospheric Disturbances (TIDs) from both an observational and modeling perspective, especially as they apply to operational systems that rely on nowcasting the ionospheric state. ASTRA has developed a new observational system to measure TID characteristics called TIDDBIT (TID Detector Built in Texas). TIDDBIT is a fully digital HF Doppler sounder that uses CW signals across a spaced array. TIDDBIT systems have been deployed in Texas, Virginia, Florida, Hawaii, and Peru. TIDDBIT measures the entire wave packet, including the horizontal and vertical phase propagation speeds as a function of TID period from the acoustic (1-min) to the gravity wave (10-90 min) part of the spectrum. It is desirable to be able to use these data to specify the TID structure not only at the measurement height, but to extend it in 3D to greater and lower heights, and beyond the immediate vicinity of the TIDDBIT system. We present a simplified model to specify TIDs based on the ion continuity equation for plasma density (Hooke 1970). Linearity of the neutral wind perturbations is assumed, and the different spectral components of the measured TID perturbations are added linearly. We use TID observations from the TIDDBIT sounder in Virginia and Peru as input into the model, and develop a 4D regional specification (spanning ~500 x 500 km in the horizontal direction and 90-1000 km altitude range) of both the perturbed electron density and the perturbed neutral wind from the corresponding atmospheric gravity wave (AGW). The model is also applied to TID measurements derived by GPS <span class="hlt">TEC</span> measurements from the continental United States during the 11 March 2011 Tohoku Earthquake to study the theoretical launch angle of AGWs from the west coast of the United States.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E3249S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E3249S"><span>Regional ionospheric model for improvement of navigation position with EGNOS</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Swiatek, Anna; Tomasik, Lukasz; Jaworski, Leszek</p> <p></p> <p>The problem of insufficient accuracy of EGNOS correction for the territory of Poland, located at the edge of EGNOS range is well known. The EEI PECS project (EGNOS EUPOS Integration) assumed improving the EGNOS correction by using the GPS observations from Polish ASG-EUPOS stations. A ionospheric delay parameter is a part of EGNOS correction. The comparative analysis of <span class="hlt">TEC</span> values obtained from EGNOS and regional permanent GNSS stations showed the systematic shift. The <span class="hlt">TEC</span> from EGNOS correction is underestimated related to computed regional <span class="hlt">TEC</span> value. The new-‘improved’ corrections computed based on regional model were substituted for the EGNOS correction for suitable message. Dynamic measurements managed using the Mobile GPS Laboratory (MGL), showed the improvement of navigation position with <span class="hlt">TEC</span> regional model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22462229-regulation-tumorigenesis-metastasis-hepatocellular-carcinoma-tumor-endothelial-cells-microrna-underlying-mechanism','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22462229-regulation-tumorigenesis-metastasis-hepatocellular-carcinoma-tumor-endothelial-cells-microrna-underlying-mechanism"><span>Regulation of tumorigenesis and metastasis of hepatocellular carcinoma tumor endothelial cells by microRNA-3178 and underlying mechanism</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Li, Wei; Shen, Shiqiang, E-mail: shenshiqiang2014@hotmail.com; Wu, Shanmin</p> <p>2015-08-28</p> <p>This study explored the effects of microRNA-3178 (miR-3178) on hepatocellular carcinoma (HCC) tumor endothelial cells (<span class="hlt">TECs</span>) and on the target mRNA. Real-time polymerase chain reaction (PCR) was performed to detect the differential expression of miR-3178 in hepatic sinusoidal endothelial cells (HSECs) and HCC <span class="hlt">TECs</span>. Furthermore, HCC <span class="hlt">TECs</span> were transfected with miR-3178 mimic/inhibitor or their respective negative controls. The expression of miR-3178 before and after transfection was confirmed through RT-PCR. The effects of miR-3178 on the proliferation, apoptosis, cell cycle, invasion, migration, and angiogenesis of HCC <span class="hlt">TECs</span> were also investigated through methyl thiazol tetrazolium assay, flow cytometry, matrigel invasion assay, transwellmore » migration assay, and tube formation assay. Early growth responsive gene 3 (EGR3), as the putative target of miR-3178, was detected through RT-PCR and Western blot. Compared with HSECs, HCC <span class="hlt">TECs</span> had lower miR-3178 expression levels (P < 0.001). MiR-3178 mimic inhibited proliferation, arrested cell cycle in G1 phase, and increased apoptosis. The numbers of migrated and invaded cells and capillary-like structures were significantly less in the mimic group than in the other groups. MiR-3178 mimic significantly decreased the mRNA and protein expression levels of EGR3. By contrast, miR-3178 inhibitor induced opposite effects. We conclude that miR-3178 was lowly expressed in HCC <span class="hlt">TECs</span>, and miR-3178 mimic specifically inhibited the proliferation, migration, invasion, and angiogenesis and promoted the apoptosis and G1 phase arrest of HCC <span class="hlt">TECs</span> in vitro through the inhibition of EGR3 expression. Thus, miR-3178 might be a critical target in HCC therapy. - Highlights: • MiR-3178 is significantly low-expression in HCC <span class="hlt">TECs</span>. • MiR-3178 acts as a tumor suppressor to inhibit tumorigenesis and metastasis. • MiR-3178 inhibit angiogenesis of HCC <span class="hlt">TECs</span>. • EGR3 may be a target gene of miR-3178. • MiR-3178 may have therapeutic</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA612662','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA612662"><span>Safe Gene Therapy for Type 1 Diabetes</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2012-10-01</p> <p>by transplanting these cells, either alone or together with FoxP3+eGFP+ T-regulatory cells into prediabetic ID-<span class="hlt">TEC</span> pups. Diabetes incidence and...transplanting these cells, either alone or together with FoxP3+eGFP+ T-regulatory cells into prediabetic ID-<span class="hlt">TEC</span> pups. Diabetes incidence and progression will...progression of islet-autoimmunity in prediabetic ID-<span class="hlt">TEC</span> pups. 38 In the fourth quarterly scientific progress report (06/28/11 - 09/27/11) of year 02</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5542202','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5542202"><span>ROS enhance angiogenic properties via regulation of NRF2 in tumor endothelial cells</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Towfik, Alam Mohammad; Akiyama, Kosuke; Ohga, Noritaka; Shindoh, Masanobu; Hida, Yasuhiro; Minowa, Kazuyuki; Fujisawa, Toshiaki; Hida, Kyoko</p> <p>2017-01-01</p> <p>Reactive oxygen species (ROS) are unstable molecules that activate oxidative stress. Because of the insufficient blood flow in tumors, the tumor microenvironment is often exposed to hypoxic condition and nutrient deprivation, which induces ROS accumulation. We isolated tumor endothelial cells (<span class="hlt">TECs</span>) and found that they have various abnormalities, although the underlying mechanisms are not fully understood. Here we showed that ROS were accumulated in tumor blood vessels and ROS enhanced <span class="hlt">TEC</span> migration with upregulation of several angiogenesis related gene expressions. It was also demonstrated that these genes were upregulated by regulation of Nuclear factor erythroid 2-related factor 2 (NRF2). Among these genes, we focused on Biglycan, a small leucine-rich proteoglycan. Inhibition of Toll-like receptors 2 and 4, known BIGLYCAN (BGN) receptors, cancelled the <span class="hlt">TEC</span> motility stimulated by ROS. ROS inhibited NRF2 expression in <span class="hlt">TECs</span> but not in NECs, and NRF2 inhibited phosphorylation of SMAD2/3, which activates transcription of BGN. These results indicated that ROS-induced BGN caused the pro-angiogenic phenotype in <span class="hlt">TECs</span> via NRF2 dysregulation. PMID:28525375</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1714209C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1714209C"><span>Statistical evidence of seismo-ionospheric precursors of the GPS total electron content in China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Yuh-Ing; Huang, Chi-Shen; Liu, Jann-Yenq</p> <p>2015-04-01</p> <p>Evidence of the seismo-ionospheric precursor (SIP) is reported by statistically investigating the relationship between the total electron content (<span class="hlt">TEC</span>) in global ionosphere map (GIM) and 56 M≥6.0 earthquakes during 1998-2013 in China. A median-based method together with the z test is employed to examine the <span class="hlt">TEC</span> variations 30 days before and after the earthquake. It is found that the <span class="hlt">TEC</span> significantly decreases 0600-1000 LT 1-6 days before the earthquake, and anomalously increases in 3 time periods of 1300-1700 LT 12-15 days; 0000-0500 LT 15-17 days; and 0500-0900 LT 22-28 days before the earthquake. The receiver operating characteristic (ROC) curve is then used to evaluate the efficiency of <span class="hlt">TEC</span> for predicting M≥6.0 earthquakes in China during a specified time period. Statistical results suggest that the SIP is the significant <span class="hlt">TEC</span> reduction in the morning period of 0600-1000 LT. The SIP is further confirmed since the area under the ROC curve is positively associated with the earthquake magnitude.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JAESc.114..393C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JAESc.114..393C"><span>Statistical evidences of seismo-ionospheric precursors applying receiver operating characteristic (ROC) curve on the GPS total electron content in China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Yuh-Ing; Huang, Chi-Shen; Liu, Jann-Yenq</p> <p>2015-12-01</p> <p>Evidence of the seismo-ionospheric precursor (SIP) is reported by statistically investigating the relationship between the total electron content (<span class="hlt">TEC</span>) in global ionosphere map (GIM) and 56 M ⩾ 6.0 earthquakes during 1998-2013 in China. A median-based method together with the z test is employed to examine the <span class="hlt">TEC</span> variations 30 days before and after the earthquake. It is found that the <span class="hlt">TEC</span> significantly decreases 0600-1000 LT 1-6 days before the earthquake, and anomalously increases in 3 time periods of 1300-1700 LT 12-15 days; 0000-0500 LT 15-17 days; and 0500-0900 LT 22-28 days before the earthquake. The receiver operating characteristic (ROC) curve is then used to evaluate the efficiency of <span class="hlt">TEC</span> for predicting M ⩾ 6.0 earthquakes in China during a specified time period. Statistical results suggest that the SIP is the significant <span class="hlt">TEC</span> reduction in the morning period of 0600-1000 LT. The SIP is further confirmed since the area under the ROC curve is positively associated with the earthquake magnitude.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PApGe.175.1139M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PApGe.175.1139M"><span>Ionospheric Response to the Magnetic Storm of 22 June 2015</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mansilla, Gustavo A.</p> <p>2018-03-01</p> <p>A global study is made of the response of the total electron content of the ionosphere (<span class="hlt">TEC</span>) to the geomagnetic storm occurred on 22 June 2015 (one of the strongest geomagnetic storms of the current Solar Cycle 24). Using data from 44 sites, a hemispheric comparison is made by considering high latitudes (> 50°), middle latitudes (30°-50°) and low latitudes (30°N-30°S). The main features observed were: increases in <span class="hlt">TEC</span> at high latitudes prior to the storm main phase, a considerable asymmetry of <span class="hlt">TEC</span> response at middle and low latitudes of the Northern Hemisphere and the Southern Hemisphere and decreases at equatorial latitudes. The long duration enhancements in <span class="hlt">TEC</span> were well correlated with increases in the O/N2 ratio but decreases in <span class="hlt">TEC</span> had not associated decreases in the O/N2 ratio as occur with the decreases in the electron density. Besides, prompt penetration electric fields can play an important role in the equatorial and low-latitude ionosphere during main phase of the storm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70156901','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70156901"><span>On the reported ionospheric precursor of the 1999 Hector Mine, California earthquake</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Thomas, Jeremy N.; Love, Jeffrey J.; Komjathy, Attila; Verkhoglyadova, Olga P.; Butala, Mark; Rivera, Nicholas</p> <p>2012-01-01</p> <p>Using Global Positioning System (GPS) data from sites near the 16 Oct. 1999 Hector Mine, California earthquake, Pulinets et al. (2007) identified anomalous changes in the ionospheric total electron content (<span class="hlt">TEC</span>) starting one week prior to the earthquake. Pulinets (2007) suggested that precursory phenomena of this type could be useful for predicting earthquakes. On the other hand, and in a separate analysis, Afraimovich et al. (2004) concluded that <span class="hlt">TEC</span> variations near the epicenter were controlled by solar and geomagnetic activity that were unrelated to the earthquake. In an investigation of these very different results, we examine <span class="hlt">TEC</span> time series of long duration from GPS stations near and far from the epicenter of the Hector Mine earthquake, and long before and long after the earthquake. While we can reproduce the essential time series results of Pulinets et al., we find that the signal they identify as anomalous is not actually anomalous. Instead, it is just part of normal global-scale <span class="hlt">TEC</span> variation. We conclude that the <span class="hlt">TEC</span> anomaly reported by Pulinets et al. is unrelated to the Hector Mine earthquake.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70003813','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70003813"><span>On the reported ionospheric precursor of the Hector Mine, California earthquake</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Thomas, J.N.; Love, J.J.; Komjathy, A.; Verkhoglyadova, O.P.; Butala, M.; Rivera, N.</p> <p>2012-01-01</p> <p>Using Global Positioning System (GPS) data from sites near the 16 Oct. 1999 Hector Mine, California earthquake, Pulinets et al. (2007) identified anomalous changes in the ionospheric total electron content (<span class="hlt">TEC</span>) starting one week prior to the earthquake. Pulinets (2007) suggested that precursory phenomena of this type could be useful for predicting earthquakes. On the other hand, and in a separate analysis, Afraimovich et al. (2004) concluded that <span class="hlt">TEC</span> variations near the epicenter were controlled by solar and geomagnetic activity that were unrelated to the earthquake. In an investigation of these very different results, we examine <span class="hlt">TEC</span> time series of long duration from GPS stations near and far from the epicenter of the Hector Mine earthquake, and long before and long after the earthquake. While we can reproduce the essential time series results of Pulinets et al., we find that the signal they identified as being anomalous is not actually anomalous. Instead, it is just part of normal global-scale <span class="hlt">TEC</span> variation. We conclude that the <span class="hlt">TEC</span> anomaly reported by Pulinets et al. is unrelated to the Hector Mine earthquake.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2013-01-09/pdf/2013-00269.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2013-01-09/pdf/2013-00269.pdf"><span>78 FR 1835 - Hand Trucks and Certain Parts Thereof From the People's Republic of China: Preliminary Results of...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2013-01-09</p> <p>... Integration (Xiamen) Co., Ltd. (New-<span class="hlt">Tec</span>) were below normal value (NV). In addition, we are not rescinding this... November 30, 2011: Weighted- Manufacturer/exporter average margin (percent) New-<span class="hlt">Tec</span> Integration (Xiamen) Co...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA51A2370Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA51A2370Z"><span>Plasma density irregularities and Total Electron Content gradients over Europe</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zakharenkova, I.; Kotulak, K.; Cherniak, I.; Krankowski, A.; Froń, A.</p> <p>2017-12-01</p> <p>Perturbations of the ionospheric plasma density are crucial from the scientific and application points of view, as they can severe affect radio signals used in the Global Navigation Satellite Systems (GNSS) and low frequency radio astronomy. For several decades the ionospheric irregularities have been extensively studied by different techniques, including ground-based GNSS observations. Spatial distribution of ionospheric disturbances can be specified by horizontal gradients of the ionospheric density (total electron content, <span class="hlt">TEC</span>). Another, widely used tool in irregularities monitoring is the rate of <span class="hlt">TEC</span> index (ROTI). Recently, the Northern Hemisphere ROTI product has been implemented to the International GNSS Service (IGS) and available for community. In this study, we present climatology of the spatial <span class="hlt">TEC</span> gradients occurred over European region at high to middle latitudes. We developed the <span class="hlt">TEC</span> gradient maps based on the high-resolution (0.5 degree in latitude and longitude) regional <span class="hlt">TEC</span> maps covering Europe. The obtained climatological characteristics of the spatial <span class="hlt">TEC</span> gradients are superimposed and analyzed with the global and regional ROTI product in order to reveal development of highly intense plasma irregularities occurred at high and middle latitudes. During geomagnetic storm the complex of physical processes at auroal zone leads to development of intnse ionospheric irregularities and travelling ionospheric disturbances (TIDs). We presents results of the geomagnetic storm analysis including the 2013 and 2015 St. Patrick's Day geomagnetic storms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Natur.527..531Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Natur.527..531Z"><span>In situ structures of the segmented genome and RNA polymerase complex inside a dsRNA virus</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Xing; Ding, Ke; Yu, Xuekui; Chang, Winston; Sun, Jingchen; Hong Zhou, Z.</p> <p>2015-11-01</p> <p>Viruses in the Reoviridae, like the triple-shelled human rotavirus and the single-shelled insect cytoplasmic polyhedrosis virus (CPV), all package a genome of segmented double-stranded RNAs (dsRNAs) inside the viral capsid and carry out endogenous messenger RNA synthesis through a transcriptional enzyme complex (<span class="hlt">TEC</span>). By direct electron-counting cryoelectron microscopy and asymmetric reconstruction, we have determined the organization of the dsRNA genome inside quiescent CPV (q-CPV) and the in situ atomic structures of <span class="hlt">TEC</span> within CPV in both quiescent and transcribing (t-CPV) states. We show that the ten segmented dsRNAs in CPV are organized with ten <span class="hlt">TECs</span> in a specific, non-symmetric manner, with each dsRNA segment attached directly to a <span class="hlt">TEC</span>. The <span class="hlt">TEC</span> consists of two extensively interacting subunits: an RNA-dependent RNA polymerase (RdRP) and an NTPase VP4. We find that the bracelet domain of RdRP undergoes marked conformational change when q-CPV is converted to t-CPV, leading to formation of the RNA template entry channel and access to the polymerase active site. An amino-terminal helix from each of two subunits of the capsid shell protein (CSP) interacts with VP4 and RdRP. These findings establish the link between sensing of environmental cues by the external proteins and activation of endogenous RNA transcription by the <span class="hlt">TEC</span> inside the virus.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AdSpR..61.2881B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AdSpR..61.2881B"><span>Empirical forecast of quiet time ionospheric Total Electron Content maps over Europe</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Badeke, Ronny; Borries, Claudia; Hoque, Mainul M.; Minkwitz, David</p> <p>2018-06-01</p> <p>An accurate forecast of the atmospheric Total Electron Content (<span class="hlt">TEC</span>) is helpful to investigate space weather influences on the ionosphere and technical applications like satellite-receiver radio links. The purpose of this work is to compare four empirical methods for a 24-h forecast of vertical <span class="hlt">TEC</span> maps over Europe under geomagnetically quiet conditions. <span class="hlt">TEC</span> map data are obtained from the Space Weather Application Center Ionosphere (SWACI) and the Universitat Politècnica de Catalunya (UPC). The time-series methods Standard Persistence Model (SPM), a 27 day median model (MediMod) and a Fourier Series Expansion are compared to maps for the entire year of 2015. As a representative of the climatological coefficient models the forecast performance of the Global Neustrelitz <span class="hlt">TEC</span> model (NTCM-GL) is also investigated. Time periods of magnetic storms, which are identified with the Dst index, are excluded from the validation. By calculating the <span class="hlt">TEC</span> values with the most recent maps, the time-series methods perform slightly better than the coefficient model NTCM-GL. The benefit of NTCM-GL is its independence on observational <span class="hlt">TEC</span> data. Amongst the time-series methods mentioned, MediMod delivers the best overall performance regarding accuracy and data gap handling. Quiet-time SWACI maps can be forecasted accurately and in real-time by the MediMod time-series approach.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27906181','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27906181"><span>STAT6 deficiency ameliorates Graves' disease severity by suppressing thyroid epithelial cell hyperplasia.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jiang, Xuechao; Zha, Bingbing; Liu, Xiaoming; Liu, Ronghua; Liu, Jun; Huang, Enyu; Qian, Tingting; Liu, Jiajing; Wang, Zhiming; Zhang, Dan; Wang, Luman; Chu, Yiwei</p> <p>2016-12-01</p> <p>Signal transducer and activator of transcription 6 (STAT6) is involved in epithelial cell growth. However, little is known regarding the STAT6 phosphorylation status in Graves' disease (GD) and its role in thyroid epithelial cells (<span class="hlt">TECs</span>). In this study, we found that STAT6 phosphorylation (p-STAT6) was significantly increased in <span class="hlt">TECs</span> from both GD patients and experimental autoimmune Graves' disease mice and that STAT6 deficiency ameliorated GD symptoms. Autocrine IL-4 signalling in <span class="hlt">TECs</span> activated the phosphorylation of STAT6 via IL-4 R engagement, and the downstream targets of STAT6 were Bcl-xL and cyclin D1. Thus, the IL-4-STAT6-Bcl-xL/cyclin D1 pathway is crucial for <span class="hlt">TEC</span> hyperplasia, which aggravates GD. More importantly, in vitro and in vivo experiments demonstrated that STAT6 phosphorylation inhibited by AS1517499 decreased <span class="hlt">TEC</span> hyperplasia, thereby reducing serum T3 and T4 and ameliorating GD. Thus, our study reveals that in addition to the traditional pathogenesis of GD, in which autoantibody TRAb stimulates thyroid-stimulating hormone receptors and consequently produces T3, T4, TRAb could also trigger <span class="hlt">TECs</span> producing IL-4, and IL-4 then acts in an autocrine manner to activate p-STAT6 signalling and stimulate unrestricted cell growth, thus aggravating GD. These findings suggest that STAT6 inhibitors could be potent therapeutics for treating GD.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DPPJO6015S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DPPJO6015S"><span>Development of a methodology for deriving Plasmaspheric Total Electron Content from In-Situ electron density measurements in highly eccentric equatorial orbits</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sadhique, Aliyuthuman; Buckley, Andrew; Gough, Paul; Sussex Space Science Centre Team</p> <p>2017-10-01</p> <p>The contribution of the Upper Plasmasphere (defined as the altitudes above semi-synchronous orbit height to the Plasmapause height) to the <span class="hlt">TEC</span> has been and continues to be un-quantified. The PEACE instrument in the Chinese - ESA Double Star TC1 satellite, the mission's orbit's high eccentricity, low perigee, high apogee and the resulting smaller incident angle while in the above altitude range provide the ideal geometric opportunity to build a methodology and to utilize its empirical in-situ electron density measurements to determine the Upper Plasmaspheric <span class="hlt">TEC</span> component. Furthermore, the variation of the Inclination Angle of TC1 makes it a suitable equatorial mission confined to the Near-Equatorial region, ie 200 - 250 on either sides of the magnetic equator. As the most pronounced absolute <span class="hlt">TEC</span> values and variations are within this region, it offers an excellent opportunity to build a Upper Plasmaspheric <span class="hlt">TEC</span> database. This research generates such, first-ever database along its orbital path, using a methodology of approximation equating arcs of the orbits to straight-line <span class="hlt">TEC</span> Bars, utilizing complex mathematics, also enabling the determination of the whole Plasmaspheric <span class="hlt">TEC</span> from any eccentric orbital probe. Presented the paper in 15th International Workshop on Technical and Scientific Aspects of MST radar (MST15/iMST2)'' and ``18th EISCAT Symposium (EISCAT18)'' in Tokyo, Japan and The Royal Astronomical Society National Astronomy Meeting 2017.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16895839','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16895839"><span>Influence of plasticizer level on the drug release from sustained release film coated and hot-melt extruded dosage forms.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhu, Yucun; Mehta, Ketan A; McGinity, James W</p> <p>2006-01-01</p> <p>In the current study, the influence of plasticizer level on drug release was investigated for solid dosage forms prepared by hot-melt extrusion and film coating. The properties of two highly water-soluble compounds, diltiazem hydrochloride (DTZ) and chlorpheniramine maleate (CPM), and a poorly water-soluble drug, indomethacin (IDM), were investigated in the melt extrudates containing either Eudragit RSPO or Eudragit RD 100 and triethyl citrate (<span class="hlt">TEC</span>) as the plasticizer. In addition, pellets containing DTZ were film coated with Eudragit RS 30D and varying levels of <span class="hlt">TEC</span> using a fluidized bed coating unit. Differential scanning calorimetry (DSC) demonstrated that both CPM and IDM exhibited a plasticization effect on the acrylic polymers, whereas no plasticizing effect by DTZ on Eudragit RSPO was observed. Thermogravimetric analysis (TGA) was used to investigate the thermal stability of the DTZ, Eudragit RSPO and <span class="hlt">TEC</span> at 140 degrees C, the maximum temperature used in the hot-melt extrusion process. The chemical stability of DTZ and IDM in the extrudate following hot-melt processing was determined by high pressure liquid chromatography (HPLC). Drug release rates of both DTZ and CPM from hot-melt extrudates increased with an increase in the <span class="hlt">TEC</span> level in the formulations, while the release rate of DTZ from the Eudragit RS 30D-coated pellets decreased with an increase in <span class="hlt">TEC</span> in the coating dispersion. This phenomenon was due to the formation of a reservoir polymeric structure as a result of the thermal stress and shear stress involved in the hot-melt extrusion process regardless of the <span class="hlt">TEC</span> level. In contrast, coalescence of the polymer particles in the film coating process was enhanced with higher levels of <span class="hlt">TEC</span>, as demonstrated by scanning electron microscopy (SEM). The addition of <span class="hlt">TEC</span> (0% to 8%) in the IDM hot-melt extrudate formulation had no influence on the drug release rate as the drug release rate was controlled by drug diffusion through the inside of the polymeric</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012cosp...39.1167M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012cosp...39.1167M"><span>New comparisons of ISR and RO data with the model IRI-Plas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maltseva, Olga; Mozhaeva, Natalya; Zhbankov, Gennadii</p> <p>2012-07-01</p> <p>Space Weather events lead to strong changes in peak parameters of the ionosphere. These parameters, foF2 and hmF2, define the N(h)-profile, which is known to include bottom side and topside parts. Numerous studies have shown that adaptation of the IRI model to the experimental values of foF2 and hmF2 gave a good agreement between experimental and model N(h)-profiles of the bottom side ionosphere. This is not about the topside N(h)-profile. To improve the situation measurements of the total electron content <span class="hlt">TEC</span> are involved. This work is devoted to the use of peak parameters with the <span class="hlt">TEC</span> during Space Weather events for the evaluation of propagation conditions in both the bottom side and the topside ionosphere, based on the model IRI-Plas. To assess how well the model N(h)-profile matches the experimental one, the model IRI-Plas is tested according to the Incoherent Scatter Radars and the Radio Occultation measurements in various parts of the globe and at different levels of solar activity. The experimental N(h)-profiles are compared with profiles for the original model, the model adapted to the foF2 and hmF2, and for a model with full adaptation (including the <span class="hlt">TEC</span>). The best fit is obtained in the European region, so the SW variations of peak parameters and N(h)-profiles are studied on the example of the European area. The IRI-Plas model allows to estimate the relative contributions of each region (bottom side BOT, topside TOP and plasmaspheric PL parts) in the value of the <span class="hlt">TEC</span>. As the analysis of two W- and Wp-indexes (Gulyaeva, 2008; Gulyaeva and Stanislawska, 2008) is shown, <span class="hlt">TEC</span>-storms occur in 2 times more likely than foF2-storms. This testifies that the variations of parts BOT, TOP and PL in the <span class="hlt">TEC</span> are different. It determines different variations of N(h)-profiles. Results are given for several types of SW-events, in particular, for the strong positive and negative disturbances, when the variations of <span class="hlt">TEC</span> and foF2 are of the same sign and the corresponding</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24728352','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24728352"><span>A regulatory role for TGF-β signaling in the establishment and function of the thymic medulla.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hauri-Hohl, Mathias; Zuklys, Saulius; Holländer, Georg A; Ziegler, Steven F</p> <p>2014-06-01</p> <p>Medullary thymic epithelial cells (m<span class="hlt">TECs</span>) are critical in establishing and maintaining the appropriate microenvironment for negative selection and maturation of immunocompetent T cells with a self-tolerant T cell antigen receptor repertoire. Cues that direct proliferation and maturation of m<span class="hlt">TECs</span> are provided by members of the tumor necrosis factor (TNF) superfamily expressed on developing thymocytes. Here we demonstrate a negative role of the morphogen TGF-β in tempering these signals under physiological conditions, limiting both growth and function of the thymic medulla. Eliminating TGF-β signaling specifically in <span class="hlt">TECs</span> or by pharmacological means increased the size of the m<span class="hlt">TEC</span> compartment, enhanced negative selection and functional maturation of medullary thymocytes as well as the production of regulatory T cells, thus reducing the autoreactive potential of peripheral T cells.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15..344S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15..344S"><span>Ionospheric Anomalies on the day of the Devastating Earthquakes during 2000-2012</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Su, Fanfan; Zhou, Yiyan; Zhu, Fuying</p> <p>2013-04-01</p> <p>The study of the ionospheric abnormal changes during the large earthquakes has attracted much attention for many years. Many papers have reported the deviations of Total Electron Content (<span class="hlt">TEC</span>) around the epicenter. The statistical analysis concludes that the anomalous behavior of <span class="hlt">TEC</span> is related with the earthquakes with high probability[1]. But the special cases have different features[2][3]. In this study, we carry out a new statistical analysis to investigate the nature of the ionospheric anomalies during the devastating earthquakes. To demonstrate the abnormal changes of the ionospheric <span class="hlt">TEC</span>, we have examined the <span class="hlt">TEC</span> database from the Global Ionosphere Map (GIM). The GIM ( ftp://cddisa.gsfc.nasa.gov/pub/gps/products/ionex) includes about 200 of worldwide ground-based receivers of the GPS. The <span class="hlt">TEC</span> data with resolution of 5° longitude and 2.5° latitude are routinely published in a 2-h time interval. The information of earthquakes is obtained from the USGS ( http://earthquake.usgs.gov/earthquakes/eqarchives/epic/). To avoid the interference of the magnetic storm, the days with Dst≤-20 nT are excluded. Finally, a total of 13 M≥8.0 earthquakes in the global area during 2000-2012 are selected. The 27 days before the main shock are treated as the background days. Here, 27-day <span class="hlt">TEC</span> median (Me) and the standard deviation (σ) are used to detect the variation of <span class="hlt">TEC</span>. We set the upper bound BU = Me + 3*σ, and the lower bound BL = Me - 3*σ. Therefore the probability of a new <span class="hlt">TEC</span> in the interval (BL, BU) is approximately 99.7%. If <span class="hlt">TEC</span> varies between BU and BL, the deviation (DTEC) equals zero. Otherwise, the deviations between <span class="hlt">TEC</span> and bounds are calculated as DTEC = BU/BL - <span class="hlt">TEC</span>. From the deviations, the positive and negative abnormal changes of <span class="hlt">TEC</span> can be evaluated. We investigate temporal and spatial signatures of the ionospheric anomalies on the day of the devastating earthquakes(M≥8.0). The results show that the occurrence rates of positive anomaly and negative</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017OptLE..91..196C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017OptLE..91..196C"><span>Three-dimensional transient thermoelectric currents in deep penetration laser welding of austenite stainless steel</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Xin; Pang, Shengyong; Shao, Xinyu; Wang, Chunming; Xiao, Jianzhong; Jiang, Ping</p> <p>2017-04-01</p> <p>The existence of thermoelectric currents (<span class="hlt">TECs</span>) in workpieces during the laser welding of metals has been common knowledge for more than 15 years. However, the time-dependent evolutions of <span class="hlt">TECs</span> in laser welding remain unclear. The present study developed a novel three-dimensional theoretical model of thermoelectric phenomena in the fiber laser welding of austenite stainless steel and used it to observe the time-dependent evolutions of <span class="hlt">TECs</span> for the first time. Our model includes the complex physical effects of thermal, electromagnetic, fluid and phase transformation dynamics occurring at the millimeter laser ablated zone, which allowed us to simulate the <span class="hlt">TEC</span>, self-induced magnetic field, Lorentz force, keyhole and weld pool behaviors varying with the welding time for different parameters. We found that <span class="hlt">TECs</span> are truly three-dimensional, time-dependent, and uneven with a maximum current density of around 107 A/m2 located at the liquid-solid (L/S) interface near the front or bottom part of the keyhole at a laser power of 1.5 kW and a welding speed of 3 m/min. The <span class="hlt">TEC</span> formed three-dimensional circulations moving from the melting front to solidification front in the solid part of workpiece, after which the contrary direction was followed in the liquid part. High frequency oscillation characteristics (2.2-8.5 kHz) were demonstrated in the <span class="hlt">TEC</span>, which coincides with that of the keyhole instability (2.0-5.0 kHz). The magnitude of the self-induced magnetic field and Lorentz force can reach 0.1 mT and 1 kN/m3, respectively, which are both consistent with literature data. The predicted results of the weld dimensions by the proposed model agree well with the experimental results. Our findings could enhance the fundamental understanding of thermoelectric phenomena in laser welding.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29576725','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29576725"><span>Are There Gender Differences in Emotion Comprehension? Analysis of the Test of Emotion Comprehension.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fidalgo, Angel M; Tenenbaum, Harriet R; Aznar, Ana</p> <p>2018-01-01</p> <p>This article examines whether there are gender differences in understanding the emotions evaluated by the Test of Emotion Comprehension (<span class="hlt">TEC</span>). The <span class="hlt">TEC</span> provides a global index of emotion comprehension in children 3-11 years of age, which is the sum of the nine components that constitute emotion comprehension: (1) recognition of facial expressions, (2) understanding of external causes of emotions, (3) understanding of desire-based emotions, (4) understanding of belief-based emotions, (5) understanding of the influence of a reminder on present emotional states, (6) understanding of the possibility to regulate emotional states, (7) understanding of the possibility of hiding emotional states, (8) understanding of mixed emotions, and (9) understanding of moral emotions. We used the answers to the <span class="hlt">TEC</span> given by 172 English girls and 181 boys from 3 to 8 years of age. First, the nine components into which the <span class="hlt">TEC</span> is subdivided were analysed for differential item functioning (DIF), taking gender as the grouping variable. To evaluate DIF, the Mantel-Haenszel method and logistic regression analysis were used applying the Educational Testing Service DIF classification criteria. The results show that the <span class="hlt">TEC</span> did not display gender DIF. Second, when absence of DIF had been corroborated, it was analysed for differences between boys and girls in the total <span class="hlt">TEC</span> score and its components controlling for age. Our data are compatible with the hypothesis of independence between gender and level of comprehension in 8 of the 9 components of the <span class="hlt">TEC</span>. Several hypotheses are discussed that could explain the differences found between boys and girls in the belief component. Given that the Belief component is basically a false belief task, the differences found seem to support findings in the literature indicating that girls perform better on this task.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20080044828&hterms=GIM+TEC+Map&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DGIM%2BTEC%2BMap','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20080044828&hterms=GIM+TEC+Map&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DGIM%2BTEC%2BMap"><span>Estimation of the Total Electron Content of the Martian Ionosphere using Radar Sounder Surface Echoes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Safaeinili, Ali; Kofman, Wlodek; Mouginot, Jeremie; Gim, Yonggyu; Herique, Alain; Ivanov, Anton B.; Plaut, Jeffrey J.; Picardi, Giovanni</p> <p>2007-01-01</p> <p>The Martian ionosphere's local total electron content (<span class="hlt">TEC</span>) and the neutral atmosphere scale height can be derived from radar echoes reflected from the surface of the planet. We report the global distribution of the <span class="hlt">TEC</span> by analyzing more than 750,000 echoes of the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS). This is the first direct measurement of the <span class="hlt">TEC</span> of the Martian ionosphere. The technique used in this paper is a novel 'transmission-mode' sounding of the ionosphere of Mars in contrast to the Active Ionospheric Sounding experiment (AIS) on MARSIS, which generally operates in the reflection mode. This technique yields a global map of the <span class="hlt">TEC</span> for the Martian ionosphere. The radar transmits a wideband chirp signal that travels through the ionosphere before and after being reflected from the surface. The received waves are attenuated, delayed and dispersed, depending on the electron density in the column directly below the spacecraft. In the process of correcting the radar signal, we are able to estimate the <span class="hlt">TEC</span> and its global distribution with an unprecedented resolution of about 0.1 deg in latitude (5 km footprint). The mapping of the relative geographical variations in the estimated nightside <span class="hlt">TEC</span> data reveals an intricate web of high electron density regions that correspond to regions where crustal magnetic field lines are connected to the solar wind. Our data demonstrates that these regions are generally but not exclusively associated with areas that have magnetic field lines perpendicular to the surface of Mars. As a result, the global <span class="hlt">TEC</span> map provides a high-resolution view of where the Martian crustal magnetic field is connected to the solar wind. We also provide an estimate of the neutral atmospheric scale height near the ionospheric peak and observe temporal fluctuations in peak electron density related to solar activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA21B2515S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA21B2515S"><span>Ionospheric variation observed in Oregon Real-time GNSS network during the total eclipse of 21 August 2017</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shahbazi, A.; Park, J.; Kim, S.; Oberg, R.</p> <p>2017-12-01</p> <p>As the ionospheric behavior is highly related to the solar activity, the total eclipse passing across the North America on 21 August 2017 is expected to significantly affect the electron density in the ionosphere along the path. Taking advantage of GNSS capability for observing total electron content (<span class="hlt">TEC</span>), this study demonstrates the impact of the total eclipse not only on the <span class="hlt">TEC</span> variation during the period of the event but also on GNSS positioning. Oregon Department of Transportation (ODOT) runs a dense real time GNSS network, referred to as Oregon Real-time GNSS network (ORGN). From the dual frequency GPS and GLONASS observations in ORGN, the <span class="hlt">TEC</span> over the network area can be extracted. We observe the vertical <span class="hlt">TEC</span> (VTEC) from the ORGN for analyzing the ionospheric condition in the local area affected by the eclipse. To observe the temporal variation, we also observe the slant <span class="hlt">TEC</span> (STEC) in each ray path and analyze the short term variation in different geometry of each ray path. Although the STEC is dependent quantity upon the changing geometry of a satellite, this approach provides insight to the ionospheric behavior of the total eclipse because the STEC does not involve the projection error, which is generated by VTEC computation. During the period of eclipse, the abnormal variations on VTEC and STEC are expected. The experimental results will be presented in time series plots for selected stations as well as the regional <span class="hlt">TEC</span> map in Oregon. In addition to the <span class="hlt">TEC</span> monitoring, we also test the positioning result of ORGN stations through Precise Point Positioning (PPP) and relative positioning. The expected result is that the both positioning results are degraded during the solar eclipse due to the instable ionospheric condition over short time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5260978','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5260978"><span>STAT6 deficiency ameliorates Graves' disease severity by suppressing thyroid epithelial cell hyperplasia</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Jiang, Xuechao; Zha, Bingbing; Liu, Xiaoming; Liu, Ronghua; Liu, Jun; Huang, Enyu; Qian, Tingting; Liu, Jiajing; Wang, Zhiming; Zhang, Dan; Wang, Luman; Chu, Yiwei</p> <p>2016-01-01</p> <p>Signal transducer and activator of transcription 6 (STAT6) is involved in epithelial cell growth. However, little is known regarding the STAT6 phosphorylation status in Graves' disease (GD) and its role in thyroid epithelial cells (<span class="hlt">TECs</span>). In this study, we found that STAT6 phosphorylation (p-STAT6) was significantly increased in <span class="hlt">TECs</span> from both GD patients and experimental autoimmune Graves' disease mice and that STAT6 deficiency ameliorated GD symptoms. Autocrine IL-4 signalling in <span class="hlt">TECs</span> activated the phosphorylation of STAT6 via IL-4 R engagement, and the downstream targets of STAT6 were Bcl-xL and cyclin D1. Thus, the IL-4-STAT6-Bcl-xL/cyclin D1 pathway is crucial for <span class="hlt">TEC</span> hyperplasia, which aggravates GD. More importantly, in vitro and in vivo experiments demonstrated that STAT6 phosphorylation inhibited by AS1517499 decreased <span class="hlt">TEC</span> hyperplasia, thereby reducing serum T3 and T4 and ameliorating GD. Thus, our study reveals that in addition to the traditional pathogenesis of GD, in which autoantibody TRAb stimulates thyroid-stimulating hormone receptors and consequently produces T3, T4, TRAb could also trigger <span class="hlt">TECs</span> producing IL-4, and IL-4 then acts in an autocrine manner to activate p-STAT6 signalling and stimulate unrestricted cell growth, thus aggravating GD. These findings suggest that STAT6 inhibitors could be potent therapeutics for treating GD. PMID:27906181</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AdSpR..61.1850R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AdSpR..61.1850R"><span>Characteristics of nighttime E-region over Arecibo: Dependence on solar flux and geomagnetic variations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Raizada, Shikha; Brum, Christiano G. M.; Mathews, John D.; Gonzalez, Cristina; Franco, Efmi</p> <p>2018-04-01</p> <p>Electron concentration (Ne) inferred from Incoherent Scatter Radar (ISR) measurements has been used to determine the influence of solar flux and geomagnetic activity in the ionospheric E-region over Arecibo Observatory (AO). The approach is based on the determination of column integrated Ne, referred to as E-region total electron content (Er<span class="hlt">TEC</span>) between 80 and 150 km altitude regions. The results discussed in this work are for the AO nighttime period. The study reveals higher Er<span class="hlt">TEC</span> values during the low solar flux periods for all the seasons except for summer period. It is found that the E-region column abundance is higher in equinox periods than in the winter for low solar activity conditions. The column integrated Ne during the post-sunset/pre-sunrise periods always exceeds the midnight minima, independent of season or solar activity. This behavior has been attributed to the variations in the coupling processes from the F-region. The response of Er<span class="hlt">TEC</span> to the geomagnetic variability is also examined for different solar flux conditions and seasons. During high solar flux periods, changes in Kp cause an Er<span class="hlt">TEC</span> increase in summer and equinox, while producing a negative storm-like effect during the winter. Variations in Er<span class="hlt">TEC</span> due to geomagnetic activity during low solar flux periods produce maximum variability in the E-region during equinox periods, while resulting in an increase/decrease in Er<span class="hlt">TEC</span> before local midnight during the winter/summer periods, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SerAJ.193...11T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SerAJ.193...11T"><span>Behaviour of Electron Content in the Ionospheric D-Region During Solar X-Ray Flares</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Todorović Drakul, M.; Čadež, V. M.; Bajčetić, J.; Popović, L. Č.; Blagojević, D.; Nina, A.</p> <p>2016-12-01</p> <p>One of the most important parameters in ionospheric plasma research, also having a wide practical application in wireless satellite telecommunications, is the total electron content (<span class="hlt">TEC</span>) representing the columnal electron number density. The F-region with high electron density provides the biggest contribution to <span class="hlt">TEC</span> while the relatively weakly ionized plasma of the D-region (60 km - 90 km above Earth's surface) is often considered as a negligible cause of satellite signal disturbances. However, sudden intensive ionization processes, like those induced by solar X-ray flares, can cause relative increases of electron density that are significantly larger in the D-region than in regions at higher altitudes. Therefore, one cannot exclude a priori the D-region from investigations of ionospheric influences on propagation of electromagnetic signals emitted by satellites. We discuss here this problem which has not been sufficiently treated in literature so far. The obtained results are based on data collected from the D-region monitoring by very low frequency radio waves and on vertical <span class="hlt">TEC</span> calculations from the Global Navigation Satellite System (GNSS) signal analyses, and they show noticeable variations in the D-region's electron content (<span class="hlt">TEC</span>_{D) during activity of a solar X-ray flare (it rises by a factor of 136 in the considered case) when <span class="hlt">TEC</span>_{D} contribution to <span class="hlt">TEC</span> can reach several percent and which cannot be neglected in practical applications like global positioning procedures by satellites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AcGeo..66...51C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AcGeo..66...51C"><span>Unbiased total electron content (UTEC), their fluctuations, and correlation with seismic activity over Japan</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cornely, Pierre-Richard; Hughes, John</p> <p>2018-02-01</p> <p>Earthquakes are among the most dangerous events that occur on earth and many scientists have been investigating the underlying processes that take place before earthquakes occur. These investigations are fueling efforts towards developing both single and multiple parameter earthquake forecasting methods based on earthquake precursors. One potential earthquake precursor parameter that has received significant attention within the last few years is the ionospheric total electron content (<span class="hlt">TEC</span>). Despite its growing popularity as an earthquake precursor, <span class="hlt">TEC</span> has been under great scrutiny because of the underlying biases associated with the process of acquiring and processing <span class="hlt">TEC</span> data. Future work in the field will need to demonstrate our ability to acquire <span class="hlt">TEC</span> data with the least amount of biases possible thereby preserving the integrity of the data. This paper describes a process for removing biases using raw <span class="hlt">TEC</span> data from the standard Rinex files obtained from any global positioning satellites system. The process is based on developing an unbiased <span class="hlt">TEC</span> (UTEC) data and model that can be more adaptable to serving as a precursor signal for earthquake forecasting. The model was used during the days and hours leading to the earthquake off the coast of Tohoku, Japan on March 11, 2011 with interesting results. The model takes advantage of the large amount of data available from the GPS Earth Observation Network of Japan to display near real-time UTEC data as the earthquake approaches and for a period of time after the earthquake occurred.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AnGeo..29.1063S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AnGeo..29.1063S"><span>Longitudinal study of the ionospheric response to the geomagnetic storm of 15 May 2005 and manifestation of TADs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sharma, S.; Galav, P.; Dashora, N.; Pandey, R.</p> <p>2011-06-01</p> <p>Response of low latitude ionosphere to the geomagnetic storm of 15 May 2005 has been studied using total electron content (<span class="hlt">TEC</span>) data, obtained from three GPS stations namely, Yibal, Udaipur and Kunming situated near the northern crest of equatorial ionization anomaly at different longitudes. Solar wind parameters, north-south component of the interplanetary magnetic field (IMF Bz) and AE index data have been used to infer the strength of the geomagnetic storm. A large value of eastward interplanetary electric field at 06:15 UT, during the time of maximum southward IMF Bz has been used to infer the transmission of an eastward prompt penetration electric field (PPEF) which resulted in a peak in <span class="hlt">TEC</span> at 07:45 UT due to the local uplift of plasma in the low latitudes near the anomaly crest over a wide range of longitudes. Wave-like modulations superposed over the second enhancement in <span class="hlt">TEC</span> between 09:15 UT to 10:30 UT have been observed at all the three stations. The second enhancement in <span class="hlt">TEC</span> along with the modulations of up to 5 TECU have been attributed to the combined effect of super plasma fountain and traveling atmospheric disturbances (TAD). Observed large enhancements in <span class="hlt">TEC</span> are a cause of concern for satellite based navigation and ground positioning. Increased [O/N2] ratio between 09:15 UT to 10:15 UT when modulations in <span class="hlt">TEC</span> have been also observed, confirms the presence of TADs over a wide range of longitudes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://rosap.ntl.bts.gov/view/dot/31419','DOTNTL'); return false;" href="https://rosap.ntl.bts.gov/view/dot/31419"><span>Home school student visit and introduction to rail transportation and engineering.</span></a></p> <p><a target="_blank" href="http://ntlsearch.bts.gov/tris/index.do">DOT National Transportation Integrated Search</a></p> <p></p> <p>2016-06-22</p> <p>This project consisted of hosting local Champaign-Urbana, Illinois home school students for a visit to : the Rail Transportation and Engineering Center (Rail<span class="hlt">TEC</span>) at the University of Illinois at Urbana- : Champaign (UIUC). Beyond visiting Rail<span class="hlt">TEC</span>, st...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27173733','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27173733"><span>Mechanisms and kinetics of proliferation and fibrosis development in a mouse model of thyrocyte hyperplasia.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ciornei, Radu Tudor; Hong, So-Hee; Fang, Yujiang; Zhu, Ziwen; Braley-Mullen, Helen</p> <p>2016-01-01</p> <p>IFN-γ(-/-) NOD.H-2h4 mice develop autoimmune disease with extensive hyperplasia and proliferation of thyroid epithelial cells (<span class="hlt">TEC</span> H/P) and fibrosis. Splenic T cells from donors with severe <span class="hlt">TEC</span> H/P transfer <span class="hlt">TEC</span> H/P to SCID recipients. The goal of this study was to determine what factors control <span class="hlt">TEC</span> H/P development/progression by examining T cells, markers of apoptosis, senescence and proliferation in thyroids of SCID recipients over time. At 28days, T cell infiltration was maximal, thyrocytes were proliferating, and fibrosis was moderate. At days 60 and 90, thyroids were larger with more fibrosis. T cells, cytokines and thyrocyte proliferation decreased, and cell cycle inhibitor proteins, and anti-apoptotic molecules increased. T cells and thyrocytes had foci of phosphorylated histone protein H2A.X, indicative of cellular senescence, when <span class="hlt">TEC</span> H/P progressed and thyrocyte proliferation declined. Some thyrocytes were regenerating at day 90, with irregularly shaped empty follicles and ciliated epithelium. Proliferating thyrocytes were thyroid transcription factor (TTF1)-positive, suggesting they derived from epithelial cells and not brachial cleft remnants. Copyright © 2016 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AcAau..81...92S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AcAau..81...92S"><span>Investigation of ionospheric scintillation at UKM station, Malaysia during low solar activity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Seif, Aramesh; Abdullah, Mardina; Marie Hasbi, Alina; Zou, Yuhua</p> <p>2012-12-01</p> <p>In this paper the investigation of the occurrence of ionospheric scintillation with S4≥0.2 was conducted by using a dual-frequency GISTM (GPS Ionospheric Scintillation and <span class="hlt">TEC</span> monitor) at Universiti Kebangsaan Malaysia station, Malaysia (2.55°N, 101.46°E; geomagnetic: 7.39°S, 173.63°E) between September 2009 and December 2010. The study shows that significant nighttime amplitude scintillation event with 0.4≤S4<0.6 mainly occurred in the months of March, September and October, while significant daytime amplitude scintillation activity took place in November and December with 0.3≤S4<0.5. Moreover, nighttime amplitude scintillation observed at UKM station always occurred with phase scintillations, total electron content (<span class="hlt">TEC</span>) depletions, rate of change of <span class="hlt">TEC</span> (ROT) fluctuations and the enhancement of rate of <span class="hlt">TEC</span> index (ROTI). Nevertheless, during daytime amplitude scintillation, <span class="hlt">TEC</span> depletions and ROT fluctuations were much weaker than those that occurred during nighttime and this may be caused by small scale irregularities in the E region, called sporadic-E (Es), while the occurrences of nighttime amplitude scintillation maybe caused by the ionospheric irregularities in the F region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19990110590','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990110590"><span>Temperature Control of Avalanche Photodiode Using Thermoelectric Cooler</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Refaat, Tamer F.; Luck, William S., Jr.; DeYoung, Russell J.</p> <p>1999-01-01</p> <p>Avalanche photodiodes (APDS) are quantum optical detectors that are used for visible and near infrared optical detection applications. Although APDs are compact, rugged, and have an internal gain mechanism that is suitable for low light intensity; their responsivity, and therefore their output, is strongly dependent on the device temperature. Thermoelectric coolers (<span class="hlt">TEC</span>) offers a suitable solution to this problem. A <span class="hlt">TEC</span> is a solid state cooling device, which can be controlled by changing its current. <span class="hlt">TECs</span> are compact and rugged, and they can precisely control the temperature to within 0.1 C with more than a 150 C temperature gradient between its surfaces. In this Memorandum, a proportional integral (PI) temperature controller for APDs using a <span class="hlt">TEC</span> is discussed. The controller is compact and can successfully cool the APD to almost 0 C in an ambient temperature environment of up to 27 C.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/9184646','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/9184646"><span>Identification of neurotensin-related peptides in human thymic epithelial cell membranes and relationship with major histocompatibility complex class I molecules.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vanneste, Y; Thome, A N; Vandersmissen, E; Charlet, C; Franchimont, D; Martens, H; Lhiaubet, A M; Schimpff, R M; Rostène, W; Geenen, V</p> <p>1997-06-01</p> <p>This study shows the expression at the cell surface of human thymic epithelial cells (<span class="hlt">TEC</span>) of a neurotensin (NT)-like immunoreactivity. NT radio-immunoassay (RIA) revealed that cultured human <span class="hlt">TEC</span> contain +/-5 ng immunoreactive (ir) NT/10(6) cells, of which 5% is associated with plasma cell membranes. HPLC analysis of NT-ir present in human <span class="hlt">TEC</span> showed a major peak of NT-ir corresponding to NT1-13. NT-ir was not detected in the supernatant of human <span class="hlt">TEC</span> cultures. Using an affinity column prepared with a anti-MHC class I monoclonal antibody, NT-ir-related peptides were retained on the column and eluted together with MHC class I-related proteins. According to the elution time on HPLC of these peptides, they correspond to intact NT1-13, as well as to smaller fragments of NT1-13.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ESASP.740E.279T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ESASP.740E.279T"><span>Classification of the Regional Ionospheric Disturbance Based on Machine Learning Techniques</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Terzi, Merve Begum; Arikan, Orhan; Karatay, Secil; Arikan, Feza; Gulyaeva, Tamara</p> <p>2016-08-01</p> <p>In this study, Total Electron Content (<span class="hlt">TEC</span>) estimated from GPS receivers is used to model the regional and local variability that differs from global activity along with solar and geomagnetic indices. For the automated classification of regional disturbances, a classification technique based on a robust machine learning technique that have found wide spread use, Support Vector Machine (SVM) is proposed. Performance of developed classification technique is demonstrated for midlatitude ionosphere over Anatolia using <span class="hlt">TEC</span> estimates generated from GPS data provided by Turkish National Permanent GPS Network (TNPGN-Active) for solar maximum year of 2011. As a result of implementing developed classification technique to Global Ionospheric Map (GIM) <span class="hlt">TEC</span> data, which is provided by the NASA Jet Propulsion Laboratory (JPL), it is shown that SVM can be a suitable learning method to detect anomalies in <span class="hlt">TEC</span> variations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA452514','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA452514"><span>Molecular Mechanisms of Hormone-Refractory Prostate Cancer</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2006-02-01</p> <p>FIN-00014 Helsinki, Finland Bmx/Etk, a member of the <span class="hlt">Tec</span>/ Btk family of nonrecep- tor kinases, has recently been shown to mediate cell motility in...Bmx, which is a member of the <span class="hlt">Tec</span>/ Btk family of tyrosine kinases (37). In addition to the SH2, SH3, and kinase domains, the <span class="hlt">Tec</span> family of tyrosine...divided and resuspended in 18 l of kinase buffer with or without 1 M Src inhibitor SU6656 in the presence of either 2 g of GST or 2 g of GST-CasSD</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5007711','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5007711"><span>The Journal Microarrays</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lin, Shu-Kun</p> <p>2011-01-01</p> <p>Our publishing company MDPI AG has its headquarters in Basel, Switzerland where there are thousands of scientists working in the laboratories of pharmaceutical companies and institutes including Novartis [1], F. Hoffmann-La Roche [2] and institutes affiliated with University of Basel [3]. In 1996, the first annual microplate conference Mip<span class="hlt">Tec</span> was held in Basel, and the Mip<span class="hlt">Tec</span> 2011 was held a few days ago in Basel [4]. I published a paper on microplate standardization presented at Mip<span class="hlt">Tec</span> 1996 in MDPI’s longest-running journal Molecules [5-7]. [....] PMID:27605331</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27605331','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27605331"><span>The Journal Microarrays.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lin, Shu-Kun</p> <p>2011-10-14</p> <p>Our publishing company MDPI AG has its headquarters in Basel, Switzerland where there are thousands of scientists working in the laboratories of pharmaceutical companies and institutes including Novartis [1], F. Hoffmann-La Roche [2] and institutes affiliated with University of Basel [3]. In 1996, the first annual microplate conference Mip<span class="hlt">Tec</span> was held in Basel, and the Mip<span class="hlt">Tec</span> 2011 was held a few days ago in Basel [4]. I published a paper on microplate standardization presented at Mip<span class="hlt">Tec</span> 1996 in MDPI's longest-running journal Molecules [5-7]. [....].</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2011-04-20/pdf/2011-9574.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2011-04-20/pdf/2011-9574.pdf"><span>76 FR 22078 - Lightweight Thermal Paper From Germany: Notice of Final Results of the First Antidumping Duty...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2011-04-20</p> <p>... DEPARTMENT OF COMMERCE International Trade Administration [A-428-840] Lightweight Thermal Paper... initiation of this antidumping duty administrative review naming Mitsubishi Hi<span class="hlt">Tec</span> Paper Flensburg GmbH, Mitsubishi Hi<span class="hlt">Tec</span> Paper Bielefeld GmbH and Mitsubishi International Corporation (``collectively, Mitsubishi...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003PhyA..321..124T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003PhyA..321..124T"><span>Ion pump as Brownian motor: theory of electroconformational coupling and proof of ratchet mechanism for Na,K-ATPase action</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsong, Tian Yow; Chang, Cheng-Hung</p> <p>2003-04-01</p> <p>This article reviews some concepts of the Brownian Ratchet which are relevant to our discussion of mechanisms of action of Na,K-ATPase, a universal ion pump and an elemental motor protein of the biological cell. Under wide ranges of ionic compositions it can hydrolyze an ATP and use the γ-phosphorous bond energy of ATP to pump 3 Na + out of, and 2 K + into the cell, both being uphill transport. During the ATP-dependent pump cycle, the enzyme oscillates between E1 and E2 states. Our experiment replaces ATP with externally applied electric field of various waveforms, amplitudes, and frequencies. The field enforced-oscillation, or fluctuation of E1 and E2 states enables the enzyme to harvest energy from the applied field and convert it to the chemical gradient energy of cations. A theory of electroconformational coupling (<span class="hlt">TEC</span>), which embodies all the essential features of the Brownian Ratchet, successfully simulates these experimental results. Our analysis based on a four-state <span class="hlt">TEC</span> model indicates that the equilibrium and the rate constants of the transport system define the frequency and the amplitude of the field for the optimal activation. Waveform, frequency, and amplitude are three elements of signal. Thus, electric signal of the ion pump is found by <span class="hlt">TEC</span> analysis of the experimental data. Electric noise (white) superimposed on an electric signal changes the pump efficiency and produces effects similar to the stochastic resonance reported in other biological systems. The <span class="hlt">TEC</span> concept is compared with the most commonly used Michaelis-Menten enzyme mechanism (MME) for similarities and differences. Both MME and <span class="hlt">TEC</span> are catalytic wheels, which recycle the catalyst in each turnover. However, a MME can only catalyze reaction of descending free energy while a <span class="hlt">TEC</span> enzyme can catalyze reaction of ascending free energy by harvesting needed energy from an off-equilibrium electric noise. The <span class="hlt">TEC</span> mechanism is shown to be applicable to other biological motors and engines, as</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17420479','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17420479"><span>SLP-76 mediates and maintains activation of the <span class="hlt">Tec</span> family kinase ITK via the T cell antigen receptor-induced association between SLP-76 and ITK.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bogin, Yaron; Ainey, Carmit; Beach, Dvora; Yablonski, Deborah</p> <p>2007-04-17</p> <p>ITK (IL-2-inducible T cell kinase), a <span class="hlt">Tec</span> family protein tyrosine kinase (PTK), is one of three PTKs required for T cell antigen receptor (TCR)-induced activation of phospholipase C-gamma1 (PLC-gamma1). Like Src and Abl family PTKs, ITK adopts an inactive, "closed" conformation, and its conversion to the active conformation is not well understood, nor have its direct substrates been identified. In a side-by-side comparison of ITK and ZAP-70 (zeta chain-associated protein kinase of 70 kDa), ITK efficiently phosphorylated Y(783) and Y(775) of PLC-gamma1, two phosphorylation sites that are critical for its activation, whereas ZAP-70 did not. SLP-76 (SH2-domain-containing leukocyte protein of 76 kDa), an adaptor required for TCR-induced activation of PLC-gamma1, was required for the phosphorylation of both PLC-gamma1 sites in intact cells. Furthermore, this event depended on the N-terminal tyrosines of SLP-76. Likewise, SLP-76, particularly its N-terminal tyrosines, was required for TCR-induced tyrosine phosphorylation and activation of ITK but was not required for the phosphorylation or activation of ZAP-70. Both ZAP-70 and ITK phosphorylated SLP-76 in vitro; thus, both PTKs are potential regulators of SLP-76, but only ITK is regulated by SLP-76. Upon TCR stimulation, a small fraction of ITK bound to SLP-76. This fraction, however, encompassed most of the catalytically active ITK. Catalytic activity was lost upon mild elution of ITK from the SLP-76-nucleated complex but was restored upon reconstitution of the complex. We propose that SLP-76 is required for ITK activation; furthermore, an ongoing physical interaction between SLP-76 and ITK is required to maintain ITK in an active conformation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..122.1221C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..122.1221C"><span>Modeling the plasmasphere based on LEO satellites onboard GPS measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Peng; Yao, Yibin; Li, Qinzheng; Yao, Wanqiang</p> <p>2017-01-01</p> <p>The plasmasphere, which is located above the ionosphere, is a significant component of Earth's atmosphere. A global plasmaspheric model was constructed using the total electron content (<span class="hlt">TEC</span>) along the signal propagation path calculated using onboard Global Positioning System observations from the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) and MetOp-A, provided by the COSMIC Data Analysis and Archive Center (CDAAC). First, the global plasmaspheric model was established using only COSMIC <span class="hlt">TEC</span>, and a set of MetOp-A <span class="hlt">TEC</span> provided by CDAAC served for external evaluation. Results indicated that the established model using only COSMIC data is highly accurate. Then, COSMIC and MetOp-A <span class="hlt">TEC</span> were combined to produce a new global plasmaspheric model. Finally, the variational characteristics of global plasmaspheric electron content with latitude, local time, and season were investigated using the global plasmaspheric model established in this paper.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=welding+AND+process&pg=3&id=ED328731','ERIC'); return false;" href="https://eric.ed.gov/?q=welding+AND+process&pg=3&id=ED328731"><span>Welding, V-<span class="hlt">TECS</span> Guide.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Moore, Charles G.; And Others</p> <p></p> <p>This guide provides job-related tasks, performance objectives, performance guides, resources, teaching activities, evaluation standards, and criterion-referenced measures in three units of a welding course. Through the curriculum content of the welding course, the guide helps teachers lead students through the learning process, including the…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AdSpR..42..737B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AdSpR..42..737B"><span>South American regional ionospheric maps computed by GESA: A pilot service in the framework of SIRGAS</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brunini, C.; Meza, A.; Gende, M.; Azpilicueta, F.</p> <p>2008-08-01</p> <p>SIRGAS (Geocentric Reference Frame for the Americas) is an international enterprise of the geodetic community that aims to realize the Terrestrial Reference Frame in the America's countries. In order to fulfill this commitment, SIRGAS manages a network of continuously operational GNSS receivers totalling around one hundred sites in the Caribbean, Central, and South American region. Although the network was not planed for ionospheric studies, its potential to be used for such a purpose was recently recognized and SIRGAS started a pilot experiment devoted to establish a regular service for computing and releasing regional vertical <span class="hlt">TEC</span> (v<span class="hlt">TEC</span>) maps based on GNSS data. Since July, 2005, the GESA (Geodesia Espacial y Aeronomía) laboratory belonging to the Facultad de Ciencias Astronómicas y Geofísicas of the Universidad Nacional de La Plata computes hourly maps of vertical Total Electron Content (v<span class="hlt">TEC</span>) in the framework of the SIRGAS pilot experiment. These maps exploit all the GNSS data available in the South American region and are computed with the LPIM (La Plata Ionospheric Model). LPIM implements a de-biasing procedure that improves data calibration in relation to other procedures commonly used for such purposes. After calibration, slant <span class="hlt">TEC</span> measurements are converted to vertical and mapped using local-time and modip latitude. The use of modip latitude smoothed the spatial variability of v<span class="hlt">TEC</span>, especially in the South American low latitude region and hence allows for a better v<span class="hlt">TEC</span> interpolation. This contribution summarizes the results obtained by GESA in the framework of the SIRGAS pilot experiment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JGRA..118.7864G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JGRA..118.7864G"><span>Evaluation of different approaches to modeling the second-order ionospheric delay on GPS measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Garcia-Fernandez, M.; Desai, S. D.; Butala, M. D.; Komjathy, A.</p> <p>2013-12-01</p> <p>This work evaluates various approaches to compute the second order ionospheric correction (SOIC) to Global Positioning System (GPS) measurements. When estimating the reference frame using GPS, applying this correction is known to primarily affect the realization of the origin of the Earth's reference frame along the spin axis (Z coordinate). Therefore, the Z translation relative to the International Terrestrial Reference Frame 2008 is used as the metric to evaluate various published approaches to determining the slant total electron content (<span class="hlt">TEC</span>) for the SOIC: getting the slant <span class="hlt">TEC</span> from GPS measurements, and using the vertical total electron content (<span class="hlt">TEC</span>) given by a Global Ionospheric Model (GIM) to transform it to slant <span class="hlt">TEC</span> via a mapping function. All of these approaches agree to 1 mm if the ionospheric shell height needed in GIM-based approaches is set to 600 km. The commonly used shell height of 450 km introduces an offset of 1 to 2 mm. When the SOIC is not applied, the Z axis translation can be reasonably modeled with a ratio of +0.23 mm/<span class="hlt">TEC</span> units of the daily median GIM vertical <span class="hlt">TEC</span>. Also, precise point positioning (PPP) solutions (positions and clocks) determined with and without SOIC differ by less than 1 mm only if they are based upon GPS orbit and clock solutions that have consistently applied or not applied the correction, respectively. Otherwise, deviations of few millimeters in the north component of the PPP solutions can arise due to inconsistencies with the satellite orbit and clock products, and those deviations exhibit a dependency on solar cycle conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..122.9032K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..122.9032K"><span>Thunderstorm-/lightning-induced ionospheric perturbation: An observation from equatorial and low-latitude stations around Hong Kong</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kumar, Sanjay; Chen, Wu; Chen, Mingli; Liu, Zhizhao; Singh, R. P.</p> <p>2017-08-01</p> <p>Total electron content (<span class="hlt">TEC</span>) computed from the network of Global Positioning System over Hong Kong area known as Hong Kong Sat-Ref-network has been used to study perturbation in the ionosphere from thunder storm activity. Data for geomagnetic quiet day (Kp < 4, on 1 April 2014) have been analyzed. The lightning activity was measured from Total Lightning sensor LS8000 over/around the Hong Kong region. Deviation in vertical <span class="hlt">TEC</span> (DTEC) and the rate of change of <span class="hlt">TEC</span> index (ROTI) have been derived and compared for lightning day of 1 April 2014 and nonlightning day of 7 April 2014. An analysis showed reduction in <span class="hlt">TEC</span> during evening hour (up to 1245 UT), whereas an enhancement during nighttime hour on the lightning day is observed. The variations in DTEC during nonlightning day are found to be insignificant in comparison to that during the lightning day. The ionospheric perturbation in <span class="hlt">TEC</span> has been noticed up to a distance around 500 km and more from the lightning center. ROTI is found to vary from 3 to 60 total electron content unit (TECU)/min (1 TECU = 1016 el m-2) on the day of thunderstorm activity, whereas ROTI is insignificant on nonlightning days. Signature of density bubbles in slant <span class="hlt">TEC</span> data and periodicities (10-100 min) in DTEC data are observed. For the same pseudorandom numbers (1, 10, 13, 23, and 28) strong amplitude scintillations are also observed at a close by station. Amplitude scintillations are proposed to be caused by plasma bubbles. The results are tentatively explained by thunderstorm-induced electric fields and gravity waves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMED11A0843A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMED11A0843A"><span>Calculating Total Electron Content under the presence of the Aurora Borealis in Fairbanks, Alaska, and Kiruna, Sweden.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ahmad, H.; Ehteshami, A.; Edgar, B.</p> <p>2015-12-01</p> <p>With the presence of the ionosphere and plasmasphere interacting with geomagnetic storms, scattering effects can be seen by the signals sent to and by GPS/GLONASS satellites. To quantify this dispersive effect, scientists look into what the culprit is that causes this signal bias on an atomic level. Results have shown that the concentration of oscillating electrons is directly proportional to the amount of bias the signal from a point on earth to a GPS satellite witnesses. This is called the Total Electron Content (<span class="hlt">TEC</span>) of a specified path, measured in electrons per meters squared (. In this project, the process of collecting and analyzing <span class="hlt">TEC</span> units was kept the same as the previous methods while keeping the cost below $3,000. Using a dual-frequency GNSS receiver from Javad, Triumph-2, the project team recorded a series of 24 hour interval data logs as the receiver stored incoming signals from any reachable satellite. Because of the dispersive media in the ionosphere, the signal witnesses a bend in its path causing a delay, called the Slant <span class="hlt">TEC</span> (s<span class="hlt">TEC</span>). Using libraries from GPStk and TEQC, we analyzed RINEX files to view the differential phase and differential pseudorange frequency to compute slant <span class="hlt">TEC</span> units (sTECU). Using the obtained data, we analyzed the difference between the s<span class="hlt">TEC</span> units collected in Houston, Texas to the ones collected in Fairbanks, Alaska. Afterwards, the project will continue on another balloon in Kiruna, Sweden at the Esrange Space Center. The receiver will be in flight this time on a 48 hour flight.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E1953T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E1953T"><span>An investigation of solar flares and associated solar radio bursts impact on ionospheric total electron content</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tuyizere, Sarathiel</p> <p>2016-07-01</p> <p>Solar transients events such as Coronal Mass Ejections (CMEs) and solar flares represent the cause of various aspects of space weather and can impact the modern man made technological system. Such solar transients are often associated with solar radio bursts (SRBs), particularly of type II and III that , at ground level can be detected by the CALLISTO (Compact Astronomical Low-frequency Low-cost Instrument for Spectroscopy and Transportable Observatories) solar spectrometer. The present study aims at investigating solar flares and associated SRBs impact on the ionospheric total electron content (<span class="hlt">TEC</span>). SRBs data used are dynamic spectra covering the 2014-2015 period and detected by the CALLISTO instrument that is installed at the university of Rwanda, Kigali. To investigate ionospheric impact, we use <span class="hlt">TEC</span> data from IGS stations located at almost the same universal time zone, and correlate the observed <span class="hlt">TEC</span> changes to the corresponding observed solar bursts events. Preliminary observations resulting from this study indicate a slight enhancement in <span class="hlt">TEC</span> during the burst event days. The observed <span class="hlt">TEC</span> enhancement on the burst day can be associated to increased UV and X-rays radiations and particle acceleration that are associated with SRBs events. This work is a contribution to more understanding of the geo-space impact of solar transients phenomena for modeling and prediction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E1968U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E1968U"><span>An investigation of solar flares and associated solar radio bursts on ionospheric total electron content</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Uwamahoro, Jean</p> <p>2016-07-01</p> <p>Solar transients events such as Coronal Mass Ejections (CMEs) and solar flares represent are the cause of various aspects of space weather and can impact the modern man made technological system. Such solar transients are often associated with solar radio bursts (SRBs), particularly of type II and III that , at ground level can be detected by the CALLISTO (Compact Astronomical Low-frequency Low-cost Instrument for Spectroscopy and Transportable Observatories) solar spectrometer. The present study aims at investigating solar flares and associated SRBs impact on the ionospheric total electron content (<span class="hlt">TEC</span>). SRBs data used are dynamic spectra covering the 2014-2015 period and detected by the CALLISTO instrument that is installed at the university of Rwanda, Kigali. To investigate ionospheric impact, we use <span class="hlt">TEC</span> data from IGS stations located at almost the same universal time zone, and correlate the observed <span class="hlt">TEC</span> changes to the corresponding observed solar bursts events. Preliminary observations resulting from this study indicate a slight enhancement in <span class="hlt">TEC</span> during the burst event days. The observed <span class="hlt">TEC</span> enhancement on the burst day can be associated to increased UV and X-rays radiations and particle acceleration that are associated with SRBs events. This work is a contribution to more understanding of the geo-space impact of solar transients phenomena for modeling and prediction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19800024713','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19800024713"><span>Optimal thermionic energy conversion with established electrodes for high-temperature topping and process heating. [coal combustion product environments</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Morris, J. F.</p> <p>1980-01-01</p> <p>Applied research-and-technology (ART) work reveals that optimal thermionic energy conversion (<span class="hlt">TEC</span>) with approximately 1000 K to approximately 1100 K collectors is possible using well established tungsten electrodes. Such <span class="hlt">TEC</span> with 1800 K emitters could approach 26.6% efficiency at 27.4 W/sq cm with approximately 1000 K collectors and 21.7% at 22.6 W/sq cm with approximately 1100 K collectors. These performances require 1.5 and 1.7 eV collector work functions (not the 1 eV ultimate) with nearly negligible interelectrode losses. Such collectors correspond to tungsten electrode systems in approximately 0.9 to approximately 6 torr cesium pressures with 1600 K to 1900 K emitters. Because higher heat-rejection temperatures for <span class="hlt">TEC</span> allow greater collector work functions, interelectrode loss reduction becomes an increasingly important target for applications aimed at elevated temperatures. Studies of intragap modifications and new electrodes that will allow better electron emission and collection with lower cesium pressures are among the <span class="hlt">TEC</span>-ART approaches to reduced interelectrode losses. These solutions will provide very effective <span class="hlt">TEC</span> to serve directly in coal-combustion products for high-temperature topping and process heating. In turn this will help to use coal and to use it well.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA41A2604M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA41A2604M"><span>Using Global Total Electron Content to Understand Interminimum Changes in Solar EUV Irradiance and Thermospheric Composition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McDonald, S. E.; Emmert, J. T.; Krall, J.; Mannucci, A. J.; Vergados, P.</p> <p>2017-12-01</p> <p>To understand how and why the distribution of geospace plasma in the ionosphere/plasmasphere is evolving over multi-decadal time scales in response to solar, heliospheric and atmospheric forcing, it is critically important to have long-term, stable datasets. In this study, we use a newly constructed dataset of GPS-based total electron content (<span class="hlt">TEC</span>) developed by JPL. The JPL Global Ionosphere Mapping (GIM) algorithm was used to generate a 35-station dataset spanning two solar minimum periods (1993-2014). We also use altimeter-derived <span class="hlt">TEC</span> measurements from TOPEX-Poseidon and Jason-1 to construct a continuous dataset for the 1995-2014 time period. Both longterm datasets are compared to each other to study interminimum changes in the global <span class="hlt">TEC</span> (during 1995-1995 and 2008-2009). We use the SAMI3 physics-based model of the ionosphere to compare the simulations of 1995-2014 with the JPL <span class="hlt">TEC</span> and TOPEX/Jason-1 datasets. To drive SAMI3, we use the Naval Research Laboratory Solar Spectral Irradiance (NRLSSI) model to specify the EUV irradiances, and NRLMSIS to specify the thermosphere. We adjust the EUV irradiances and thermospheric constituents to match the <span class="hlt">TEC</span> datasets and draw conclusions regarding sources of the differences between the two solar minimum periods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeoRL..42.9156S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeoRL..42.9156S"><span>Vertical structure of medium-scale traveling ionospheric disturbances</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ssessanga, Nicholas; Kim, Yong Ha; Kim, Eunsol</p> <p>2015-11-01</p> <p>We develop an algorithm of computerized ionospheric tomography (CIT) to infer information on the vertical and horizontal structuring of electron density during nighttime medium-scale traveling ionospheric disturbances (MSTIDs). To facilitate digital CIT we have adopted total electron contents (<span class="hlt">TEC</span>) from a dense Global Positioning System (GPS) receiver network, GEONET, which contains more than 1000 receivers. A multiplicative algebraic reconstruction technique was utilized with a calibrated IRI-2012 model as an initial solution. The reconstructed F2 peak layer varied in altitude with average peak-to-peak amplitude of ~52 km. In addition, the F2 peak layer anticorrelated with <span class="hlt">TEC</span> variations. This feature supports a theory in which nighttime MSTID is composed of oscillating electric fields due to conductivity variations. Moreover, reconstructed <span class="hlt">TEC</span> variations over two stations were reasonably close to variations directly derived from the measured <span class="hlt">TEC</span> data set. Our tomographic analysis may thus help understand three-dimensional structure of MSTIDs in a quantitative way.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19..670Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19..670Y"><span>Morphology of the winter anomaly in NmF2 and Total Electron Content</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yasyukevich, Yury; Ratovsky, Konstantin; Yasyukevich, Anna; Klimenko, Maksim; Klimenko, Vladimir; Chirik, Nikolay</p> <p>2017-04-01</p> <p>We analyzed the winter anomaly manifestation in the F2 peak electron density (NmF2) and Total Electron Content (<span class="hlt">TEC</span>) based on the observation data and model calculation results. For the analysis we used 1998-2015 <span class="hlt">TEC</span> Global Ionospheric Maps (GIM) and NmF2 ground-based ionosonde observation data from and COSMIC, CHAMP and GRACE radio occultation data. We used Global Self-consistent Model of the Thermosphere, Ionosphere, and Protonosphere (GSM TIP) and International Reference Ionosphere model (IRI-2012). Based on the observation data and model calculation results we constructed the maps of the winter anomaly intensity in <span class="hlt">TEC</span> and NmF2 for the different solar and geomagnetic activity levels. The winter anomaly intensity was found to be higher in NmF2 than in <span class="hlt">TEC</span> according to both observation and modeling. In this report we show the similarity and difference in winter anomaly as revealed in experimental data and model results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012CG.....46..189L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012CG.....46..189L"><span>Ionospheric total electron content anomalies due to Typhoon Nakri on 29 May 2008: A nonlinear principal component analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lin, Jyh-Woei</p> <p>2012-09-01</p> <p>This paper uses Nonlinear Principal Component Analysis (NLPCA) and Principal Component Analysis (PCA) to determine Total Electron Content (<span class="hlt">TEC</span>) anomalies in the ionosphere for the Nakri Typhoon on 29 May, 2008 (UTC). NLPCA, PCA and image processing are applied to the global ionospheric map (GIM) with transforms conducted for the time period 12:00-14:00 UT on 29 May 2008 when the wind was most intense. Results show that at a height of approximately 150-200 km the <span class="hlt">TEC</span> anomaly using NLPCA is more localized; however its intensity increases with height and becomes more widespread. The <span class="hlt">TEC</span> anomalies are not found by PCA. Potential causes of the results are discussed with emphasis given to vertical acoustic gravity waves. The approximate position of the typhoon's eye can be detected if the GIM is divided into fine enough maps with adequate spatial-resolution at GPS-<span class="hlt">TEC</span> receivers. This implies that the trace of the typhoon in the regional GIM is caught using NLPCA.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018GeoRL..45.3820M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018GeoRL..45.3820M"><span>Direct EUV/X-Ray Modulation of the Ionosphere During the August 2017 Total Solar Eclipse</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mrak, Sebastijan; Semeter, Joshua; Drob, Douglas; Huba, J. D.</p> <p>2018-05-01</p> <p>The great American total solar eclipse of 21 August 2017 offered a fortuitous opportunity to study the response of the atmosphere and ionosphere using a myriad of ground instruments. We have used the network of U.S. Global Positioning System receivers to examine perturbations in maps of ionospheric total electron content (<span class="hlt">TEC</span>). Coherent large-scale variations in <span class="hlt">TEC</span> have been interpreted by others as gravity wave-induced traveling ionospheric disturbances. However, the solar disk had two active regions at that time, one near the center of the disk and one at the edge, which resulted in an irregular illumination pattern in the extreme ultraviolet (EUV)/X-ray bands. Using detailed EUV occultation maps calculated from the National Aeronautics and Space Administration Solar Dynamics Observatory Atmospheric Imaging Assembly images, we show excellent agreement between <span class="hlt">TEC</span> perturbations and computed gradients in EUV illumination. The results strongly suggest that prominent large-scale <span class="hlt">TEC</span> disturbances were consequences of direct EUV modulation, rather than gravity wave-induced traveling ionospheric disturbances.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006cosp...36.3165N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006cosp...36.3165N"><span>Use of Total Electron Content data to analyze ionosphere electron density gradients</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nava, B.; Radicella, S. M.; Leitinger, R.; Coisson, P.</p> <p></p> <p>In presence of electron density gradients the thin shell approximation for the ionosphere used together with a simple mapping function to convert slant Total Electron Content <span class="hlt">TEC</span> to vertical <span class="hlt">TEC</span> could lead to <span class="hlt">TEC</span> conversion errors Therefore these mapping function errors can be used to identify the effects of the electron density gradients in the ionosphere In the present work high precision GPS derived slant <span class="hlt">TEC</span> data have been used to investigate the effects of the electron density gradients in the middle and low latitude ionosphere under geomagnetic quiet and disturbed conditions In particular the data corresponding to the geographic area of the American sector for the days 5-7 April 2000 have been used to perform a complete analysis of mapping function errors based on the coinciding pierce point technique The results clearly illustrate the electron density gradient effects according to the locations considered and to the actual levels of disturbance of the ionosphere</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.G31B1064C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.G31B1064C"><span>Near Real-time GNSS-based Ionospheric Model using Expanded Kriging in the East Asia Region</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Choi, P. H.; Bang, E.; Lee, J.</p> <p>2016-12-01</p> <p>Many applications which utilize radio waves (e.g. navigation, communications, and radio sciences) are influenced by the ionosphere. The technology to provide global ionospheric maps (GIM) which show ionospheric Total Electron Content (<span class="hlt">TEC</span>) has been progressed by processing GNSS data. However, the GIMs have limited spatial resolution (e.g. 2.5° in latitude and 5° in longitude), because they are generated using globally-distributed and thus relatively sparse GNSS reference station networks. This study presents a near real-time and high spatial resolution <span class="hlt">TEC</span> model over East Asia by using ionospheric observables from both International GNSS Service (IGS) and local GNSS networks and the expanded kriging method. New signals from multi-constellation (e.g,, GPS L5, Galileo E5) were also used to generate high-precision <span class="hlt">TEC</span> estimates. The newly proposed estimation method is based on the universal kriging interpolation technique, but integrates <span class="hlt">TEC</span> data from previous epochs to those from the current epoch to improve the <span class="hlt">TEC</span> estimation performance by increasing ionospheric observability. To propagate previous measurements to the current epoch, we implemented a Kalman filter whose dynamic model was derived by using the first-order Gauss-Markov process which characterizes temporal ionospheric changes under the nominal ionospheric conditions. Along with the <span class="hlt">TEC</span> estimates at grids, the method generates the confidence bounds on the estimates using resulting estimation covariance. We also suggest to classify the confidence bounds into several categories to allow users to recognize the quality levels of <span class="hlt">TEC</span> estimates according to the requirements for user's applications. This paper examines the performance of the proposed method by obtaining estimation results for both nominal and disturbed ionospheric conditions, and compares these results to those provided by GIM of the NASA Jet propulsion Laboratory. In addition, the estimation results based on the expanded kriging method are</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JGRA..123.1441S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JGRA..123.1441S"><span>Performance of Solar Proxy Options of IRI-Plas Model for Equinox Seasons</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sezen, Umut; Gulyaeva, Tamara L.; Arikan, Feza</p> <p>2018-02-01</p> <p>International Reference Ionosphere (IRI) is the most acclaimed climatic model of the ionosphere. Since 2009, the range of the IRI model has been extended to the Global Positioning System (GPS) orbital height of 20,000 km in the plasmasphere. The new model, which is called IRI extended to Plasmasphere (IRI-Plas), can input not only the ionosonde foF2 and hmF2 but also the GPS-total electron content (<span class="hlt">TEC</span>). IRI-Plas has been provided at www.ionolab.org, where online computation of ionospheric parameters is accomplished through a user-friendly interface. The solar proxies that are available in IRI-Plas can be listed as sunspot number (SSN1), SSN2, F10.7, global electron content (GEC), <span class="hlt">TEC</span>, IG, Mg II, Lyman-α, and GEC_RZ. In this study, ionosonde foF2 data are compared with IRI-Plas foF2 values with the Consultative Committee International Radio (CCIR) and International Union of Radio Science (URSI) model choices for each solar proxy, with or without the GPS-<span class="hlt">TEC</span> input for the equinox months of October 2011 and March 2015. It has been observed that the best fitting model choices in Root Mean Square (RMS) and Normalized RMS (NRMS) sense are the Jet Propulsion Laboratory global ionospheric maps-<span class="hlt">TEC</span> input with Lyman-α solar proxy option for both months. The input of <span class="hlt">TEC</span> definitely lowers the difference between the model and ionosonde foF2 values. The IG and Mg II solar proxies produce similar model foF2 values, and they usually are the second and third best fits to the ionosonde foF2 for the midlatitude ionosphere. In high-latitude regions, Jet Propulsion Laboratory global ionospheric map-<span class="hlt">TEC</span> inputs to IRI-Plas with Lyman-α, GEC_RZ, and <span class="hlt">TEC</span> solar proxies are the best choices. In equatorial region, the best fitting solar proxies are IG, Lyman-α, and Mg II.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JSWSC...6A..36H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JSWSC...6A..36H"><span>Ionospheric response over Europe during the solar eclipse of March 20, 2015</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hoque, Mohammed Mainul; Wenzel, Daniela; Jakowski, Norbert; Gerzen, Tatjana; Berdermann, Jens; Wilken, Volker; Kriegel, Martin; Sato, Hiroatsu; Borries, Claudia; Minkwitz, David</p> <p>2016-10-01</p> <p>The solar eclipse on March 20, 2015 was a fascinating event for people in Northern Europe. From a scientific point of view, the solar eclipse can be considered as an in situ experiment on the Earth's upper atmosphere with a well-defined switching off and on of solar irradiation. Due to the strong changes in solar radiation during the eclipse, dynamic processes were initiated in the atmosphere and ionosphere causing a measurable impact, for example, on temperature and ionization. We analyzed the behavior of total ionospheric ionization over Europe by reconstructing total electron content (<span class="hlt">TEC</span>) maps and differential <span class="hlt">TEC</span> maps. Investigating the large depletion zone around the shadow spot, we found a <span class="hlt">TEC</span> reduction of up to 6 <span class="hlt">TEC</span> units, i.e., the total plasma depletion reached up to about 50%. However, the March 20, 2015 eclipse occurred during the recovery phase of a strong geomagnetic storm and the ionosphere was still perturbed and depleted. Therefore, the unusual high depletion is due to the negative bias of up to 20% already observed over Northern Europe before the eclipse occurred. After removing the negative storm effect, the eclipse-induced depletion amounts to about 30%, which is in agreement with previous observations. During the solar eclipse, ionospheric plasma redistribution processes significantly affected the shape of the electron density profile, which is seen in the equivalent slab thickness derived by combining vertical incidence sounding (VS) and <span class="hlt">TEC</span> measurements. We found enhanced slab thickness values revealing, on the one hand, an increased width of the ionosphere around the maximum phase and, on the other, evidence for delayed depletion of the topside ionosphere. Additionally, we investigated very low frequency (VLF) signal strength measurements and found immediate amplitude changes due to ionization loss at the lower ionosphere during the eclipse time. We found that the magnitude of <span class="hlt">TEC</span> depletion is linearly dependent on the Sun's obscuration</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2012-01-10/pdf/2012-242.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2012-01-10/pdf/2012-242.pdf"><span>77 FR 1464 - Hand Trucks and Certain Parts Thereof From the People's Republic of China: Preliminary Results of...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2012-01-10</p> <p>... Surrogate Values Memorandum at Exhibit 8. Other inputs consisted of water, electricity, carbon dioxide, and.... See New-<span class="hlt">Tec</span> Surrogate Values Memorandum at Exhibit 4. We valued carbon dioxide and liquid petroleum... Integration (Xiamen) Co., Ltd. (New-<span class="hlt">Tec</span>), were below normal value (NV) at a de minimis level. We invite...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/5238894-interleukin-stimulates-zinc-uptake-human-thymic-epithelial-cells','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/5238894-interleukin-stimulates-zinc-uptake-human-thymic-epithelial-cells"><span>Interleukin-1 stimulates zinc uptake by human thymic epithelial cells</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Coto, J.A.; Hadden, J.W.</p> <p>1991-03-15</p> <p>Thymic epithelial cells (<span class="hlt">TEC</span>) are known to secrete peptides which influence the differentiation and maturation of T-lymphocytes. These peptides include the thymic hormones thymulin, thymosin-{alpha}1, and thymopoietin. The biological activity of thymulin is dependent on the presence of zinc in an equimolar ratio. The authors have shown that both interleukin-1{alpha}(IL-1{alpha}) and interleukin-1{beta}(IL-1{beta}), which stimulate proliferation of <span class="hlt">TEC</span>, stimulate the uptake of Zn-65 in-vitro independent of this proliferation. Mitomycin-C was used to inhibit the proliferation of <span class="hlt">TEC</span>. Two other stimulators of proliferation of <span class="hlt">TEC</span>, bovine pituitary extract (BPE) and epidermal growth factor (EGF), did not stimulate zinc uptake by the TECmore » independent of proliferation. They have also shown, utilizing in-situ hybridization, that IL-1 and zinc induce metallothionein(MT) mRNA expression in human thymic epithelial cells. The exact role of metallothionein is not clear, but it is thought to be involved in regulation of trace metal metabolism, especially in maintenance of zinc homeostasis. Their current hypothesis is that IL-1 stimulates uptake of zinc into the <span class="hlt">TEC</span>, followed by its complexing with metallothionein. Zinc is then thought to be transferred from metallothionein to thymulin. Immunostaining, utilizing an antithymulin antibody and a fluoresceinated goat anti-rabbit second antibody, confirms the presence of thymulin in <span class="hlt">TEC</span> and its dependence on zinc. Upon stimulation, thymulin is then secreted. Known stimulants for thymulin include progesterone, dexamethasone, estradiol, testosterone, and prolactin. None of these secretagogues increase zinc uptake, suggesting the priming of the zinc-thymulin complex is unrelated to the regulation of its secretion.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29238040','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29238040"><span>IL-3R-alpha blockade inhibits tumor endothelial cell-derived extracellular vesicle (EV)-mediated vessel formation by targeting the β-catenin pathway.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lombardo, Giusy; Gili, Maddalena; Grange, Cristina; Cavallari, Claudia; Dentelli, Patrizia; Togliatto, Gabriele; Taverna, Daniela; Camussi, Giovanni; Brizzi, Maria Felice</p> <p>2018-03-01</p> <p>The proangiogenic cytokine Interleukin-3 (IL-3) is released by inflammatory cells in breast and ovarian cancer tissue microenvironments and also acts as an autocrine factor for human breast and kidney tumor-derived endothelial cells (<span class="hlt">TECs</span>). We have previously shown that IL-3-treated endothelial cells (ECs) release extracellular vesicles (EVs), which serve as a paracrine mechanism for neighboring ECs, by transferring active molecules. The impact of an anti-IL-3R-alpha blocking antibody on the proangiogenic effect of EVs released from <span class="hlt">TECs</span> (anti-IL-3R-EVs) has therefore been investigated in this study. We have found that anti-IL-3R-EV treatment prevented neovessel formation and, more importantly, also induced the regression of in vivo <span class="hlt">TEC</span>-derived neovessels. Two miRs that target the canonical wingless (Wnt)/β-catenin pathway, at different levels, were found to be differentially regulated when comparing the miR-cargo of naive <span class="hlt">TEC</span>-derived EVs (EVs) and anti-IL-3R-EVs. miR-214-3p, which directly targets β-catenin, was found to be upregulated, whereas miR-24-3p, which targets adenomatous polyposis coli (APC) and glycogen synthase kinase-3β (GSK3β), was found to be downregulated. In fact, upon their transfer into the cell, low β-catenin content and high levels of the two members of the "β-catenin destruction complex" were detected. Moreover, c-myc downregulation was found in <span class="hlt">TECs</span> treated with anti-IL-3R-EVs, pre-miR-214-3p-EVs and antago-miR-24-3p-EVs, which is consistent with network analyses of miR-214-3p and miR-24-3p gene targeting. Finally, in vivo studies have demonstrated the impaired growth of vessels in pre-miR-214-3p-EV- and antago-miR-24-3p-EV-treated animals. These effects became much more evident when combo treatment was applied. The results of the present study identify the canonical Wnt/β-catenin pathway as a relevant mechanism of <span class="hlt">TEC</span>-derived EV proangiogenic action. Furthermore, we herein provide evidence that IL-3R blockade may yield some</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24406392','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24406392"><span>Comparison of two commercial vaccines against visceral leishmaniasis in dogs from endemic areas: IgG, and subclasses, parasitism, and parasite transmission by xenodiagnosis.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fernandes, Consuelo Barreto; Junior, Jairo Torres Magalhães; de Jesus, Clauceane; Souza, Bárbara Maria Paraná da Silva; Larangeira, Daniela Farias; Fraga, Deborah Bittencourt Mothé; Tavares Veras, Patricia Sampaio; Barrouin-Melo, Stella Maria</p> <p>2014-03-05</p> <p>The incidence of zoonotic canine visceral leishmaniasis (CVL) would decrease if dogs were effectively vaccinated; however, additional data on the efficacy of canine vaccines are required for their approved preventative use. To prospectively evaluate vaccination outcomes using two products commercially available in Brazil, with respect to adverse reactions (reactogenicity), humoral response, disease signs, parasitism, and parasite infectiousness in naturally exposed pet dogs in an endemic area of visceral leishmaniasis (VL). From 2010 to 2012, healthy dogs were vaccinated with Leishmune(®) (50 animals) or Leish-<span class="hlt">Tec</span>(®) (50 animals). Each dog was examined to identify clinical signs during peri- and post-vaccination procedures every 2 months for 11 months to identify the presence of parasites or parasite DNA in splenic samples using culturing or PCR, respectively. Levels of anti-Leishmania IgG, IgG1, and IgG2 were quantified in sera by ELISA and infectiousness was assessed by xenodiagnosis. Adverse effects occurred in 2.2% (1/45) and 13.0% (6/46) of the animals in the Leishmune(®) and Leish-<span class="hlt">Tec</span>(®) groups, respectively. IgG levels peaked on the 21st day following the first dose of Leishmune(®) and on the 21st day after the second dose of Leish-<span class="hlt">Tec</span>(®). The final seropositivity rate for IgG was 32.5% (13/40) and 30.9% (13/42) in the Leishmune(®) and Leish-<span class="hlt">Tec</span>(®) groups, respectively. The Leishmune(®) group presented higher levels of IgG1 and IgG2 compared to the Leish-<span class="hlt">Tec</span>(®) group (p<0.001), and ELISA reactivity in both vaccinated groups was significantly lower (p<0.001) than in infected positive control dogs. Parasitism was observed in 12.2% (5/41) of the Leishmune(®) group, and 7.9% (3/38) of the Leish-<span class="hlt">Tec</span>(®) group, with xenodiagnostic transmission rates of Leishmania to Lutzomyia longipalpis of 5.1% (2/39), and 5.4% (2/37), respectively. No significant differences were observed in dogs vaccinated with Leishmune(®) or Leish-<span class="hlt">Tec</span>(®), with respect to LVC</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.3196B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.3196B"><span>Study of the Total Electron Content in Mars ionosphere from MARSIS data set</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bergeot, Nicolas; Witasse, Olivier; Kofman, Wlodek; Grima, Cyril; Mouginot, Jeremie; Peter, Kerstin; Pätzold, Martin; Dehant, Véronique</p> <p>2016-04-01</p> <p>Centimeter level accuracy on the signal delay will be required on X-band radio link for future Mars landers such as InSIGHT, aiming at better determining the interior structure of Mars. One of the main error sources in the estimated signal delay is directly linked to the Total Electron Content (<span class="hlt">TEC</span>) values at Earth and Mars ionosphere level. While the Earth ionosphere is now well modeled and monitored at regional and global scales, this is not the case concerning the Mars' upper atmosphere. The present paper aims at establishing the basis to model the climatological behavior of the <span class="hlt">TEC</span> on a global scale in the Mars' ionosphere. For that we analyzed ˜8.5 years of data (mid-2005 to 2014) of the vertical Total Electron Content (v<span class="hlt">TEC</span>) expressed in <span class="hlt">TEC</span> units (1 TECu = 1016e-.m-2) from the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) radar. Our study takes advantage of the double data set of EUV solar index and Mars v<span class="hlt">TEC</span> data to develop an empirical Model of Mars Ionosphere (MoMo). The finality of this model is to predict the v<span class="hlt">TEC</span> at a given latitude, solar zenith angle and season taking only F10.7P solar index as input. To minimize the differences during the least-square adjustment between the modeled and observed v<span class="hlt">TEC</span>, we considered (1) a 4th-order polynomial function to describe the v<span class="hlt">TEC</span> diurnal behavior (2) a discretization with respect to Mars seasons (depending on Ls) and (3) two latitudinal sectors (North and South hemispheres). The mean of the differences between the model and the observations is 0.00±0.07 TECu with an error of the model around 0.1 TECu depending on the Solar Zenith Angle (SZA), season and hemisphere of interest (e.g. rms 0.12 TECu for SZA equal to 50°±5° in the Northern hemisphere during the spring season). Additionally, comparison with 250 Mars Express radio occultation data shows differences with MoMo predictions of 0.02±0.06 TECu for solar zenith angles below 50 degrees. Using the model we (1) highlighted</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=119312&keyword=VR&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=119312&keyword=VR&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT - ON-SITE SODIUM HYPOCHLORITE GENERATION AND INACTIVATION OF PSEUDOMONAS IN RAW DRINKING WATER, CLORTEC T-12 EXCELTEC INTERNATIONAL CORPORATION, A SUBSIDIARY OF SEVERN TRENT SERVICES, INC.</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Verification testing of Excel<span class="hlt">Tec</span>'s on-site hypochlorite generation system Clor<span class="hlt">Tec</span> T-12 system was conducted for 30 days between 3/6-5/4/2000. The system is capable of producing at least one pound of chlorine in the form of sodium hypochlorite solution containing 0.8% +/- 0.1%) ch...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3690271','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3690271"><span>Ionospheric Anomalies Related to the (M = 7.3), August 27, 2012, Puerto Earthquake, (M = 6.8), August 30, 2012 Jan Mayen Island Earthquake, and (M = 7.6), August 31, 2012, Philippines Earthquake: Two-Dimensional Principal Component Analysis</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lin, Jyh-Woei</p> <p>2013-01-01</p> <p>Two-dimensional principal component analysis (2DPCA) and principal component analysis (PCA) are used to examine the ionospheric total electron content (<span class="hlt">TEC</span>) data during the time period from 00:00 on August 21 to 12: 45 on August 31 (UT), which are 10 days before the M = 7.6 Philippines earthquake at 12:47:34 on August 31, 2012 (UT) with the depth at 34.9 km. From the results by using 2DPCA, a <span class="hlt">TEC</span> precursor of Philippines earthquake is found during the time period from 4:25 to 4:40 on August 28, 2012 (UT) with the duration time of at least 15 minutes. Another earthquake-related <span class="hlt">TEC</span> anomaly is detectable for the time period from 04:35 to 04:40 on August 27, 2012 (UT) with the duration time of at least 5 minutes during the Puerto earthquake at 04: 37:20 on August 27, 2012 (UT) (M w = 7.3) with the depth at 20.3 km. The precursor of the Puerto earthquake is not detectable. <span class="hlt">TEC</span> anomaly is not to be found related to the Jan Mayen Island earthquake (M w = 6.8) at 13:43:24 on August 30, 2012 (UT). These earthquake-related <span class="hlt">TEC</span> anomalies are detectable by using 2DPCA rather than PCA. They are localized nearby the epicenters of the Philippines and Puerto earthquakes. PMID:23844386</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5845020','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5845020"><span>The Electronic Health Literacy and Utilization of Technology for Health in a Remote Hawaiian Community: Lana‘i</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Humphry, Joseph</p> <p>2018-01-01</p> <p>The Lana‘i Community Health Center (LCHC) like other health care organizations, is striving to implement technology-enabled care (<span class="hlt">TEC</span>) in the clinical setting. <span class="hlt">TEC</span> includes such technological innovations as patient portals, mobile phone applications, wearable health sensors, and telehealth. This study examines the utilization of communication technology by members of the Lana‘i community and LCHC staff and board members in the home and in their daily lives and evaluates the community's electronic health literacy. Quantitative surveys and qualitative focus groups were utilized. These revealed that members of the Lana‘i community and LCHC staff and board members regularly utilize technology, in the form of smart cell phones, WiFi, and internet texting. This community has integrated technology into their daily lives, even though they live on an isolated island with 3,102 people; however, despite this integration, the electronic health literacy of this population appears insufficient for proper understanding and utilization of <span class="hlt">TEC</span>, limiting the potential of patient portals or remote monitoring of patient generated data for chronic disease prevention and management without additional education and mentoring. It is therefore in the best interest of the LCHC and other health organizations wishing to implement <span class="hlt">TEC</span> in a rural community such as Lana‘i to include a strong educational component with use of <span class="hlt">TEC</span>, and perhaps establish a mentor/partnership program for the highly-challenged patient. PMID:29541550</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/871135','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/servlets/purl/871135"><span>Fiber optic assembly and method of making same</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Kramer, Daniel P.; Beckman, Thomas M.</p> <p>1997-09-02</p> <p>There is provided an assembly having a light guiding medium sealed to a her. Preferably the holder is a metal shell and a light guiding medium is an optical fiber of glass or sapphire whisker. The assembly includes a sealing medium which sealingly engages the metal holder to the fiber. In the formation of the assembly, the seal is essentially hermetic having a capability of minimizing leakage having a helium leak rate of less than 1.times.10.sup.-8 cubic centimeters per second and high strength having a capability of withstanding pressures of 100,000 psi or greater. The features of the assembly are obtained by a specific preparation method and by selection of specific starting materials. The fiber is selected to have a sufficiently high coefficient of thermal expansion which minimizes strains in the component during fabrication, as a result of fabrication, and during use. The other components are selected to be of a material having compatible coefficients of thermal expansion (<span class="hlt">TEC</span>) where the <span class="hlt">TEC</span> of the holder is greater than or equal to the <span class="hlt">TEC</span> of the sealing material. The <span class="hlt">TEC</span> of the sealing material is in turn greater than or equal to the <span class="hlt">TEC</span> of the fiber. It is preferred that the materials be selected so that their respective coefficients of thermal expansion are as close as possible to one another and they may all be equal.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29541550','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29541550"><span>The Electronic Health Literacy and Utilization of Technology for Health in a Remote Hawaiian Community: Lana'i.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Witten, Nash Ak; Humphry, Joseph</p> <p>2018-03-01</p> <p>The Lana'i Community Health Center (LCHC) like other health care organizations, is striving to implement technology-enabled care (<span class="hlt">TEC</span>) in the clinical setting. <span class="hlt">TEC</span> includes such technological innovations as patient portals, mobile phone applications, wearable health sensors, and telehealth. This study examines the utilization of communication technology by members of the Lana'i community and LCHC staff and board members in the home and in their daily lives and evaluates the community's electronic health literacy. Quantitative surveys and qualitative focus groups were utilized. These revealed that members of the Lana'i community and LCHC staff and board members regularly utilize technology, in the form of smart cell phones, WiFi, and internet texting. This community has integrated technology into their daily lives, even though they live on an isolated island with 3,102 people; however, despite this integration, the electronic health literacy of this population appears insufficient for proper understanding and utilization of <span class="hlt">TEC</span>, limiting the potential of patient portals or remote monitoring of patient generated data for chronic disease prevention and management without additional education and mentoring. It is therefore in the best interest of the LCHC and other health organizations wishing to implement <span class="hlt">TEC</span> in a rural community such as Lana'i to include a strong educational component with use of <span class="hlt">TEC</span>, and perhaps establish a mentor/partnership program for the highly-challenged patient.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018Icar..299..396C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018Icar..299..396C"><span>Improved estimation of Mars ionosphere total electron content</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cartacci, M.; Sánchez-Cano, B.; Orosei, R.; Noschese, R.; Cicchetti, A.; Witasse, O.; Cantini, F.; Rossi, A. P.</p> <p>2018-01-01</p> <p>We describe an improved method to estimate the Total Electron Content (<span class="hlt">TEC</span>) of the Mars ionosphere from the echoes recorded by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) (Picardi et al., 2005; Orosei et al., 2015) onboard Mars Express in its subsurface sounding mode. In particular, we demonstrate that this method solves the issue of the former algorithm described at (Cartacci et al., 2013), which produced an overestimation of <span class="hlt">TEC</span> estimates on the day side. The MARSIS signal is affected by a phase distortion introduced by the Mars ionosphere that produces a variation of the signal shape and a delay in its travel time. The new <span class="hlt">TEC</span> estimation is achieved correlating the parameters obtained through the correction of the aforementioned effects. In detail, the knowledge of the quadratic term of the phase distortion estimated by the Contrast Method (Cartacci et al., 2013), together with the linear term (i.e. the extra time delay), estimated through a radar signal simulator, allows to develop a new algorithm particularly well suited to estimate the <span class="hlt">TEC</span> for solar zenith angles (SZA) lower than 95° The new algorithm for the dayside has been validated with independent data from MARSIS in its Active Ionospheric Sounding (AIS) operational mode, with comparisons with other previous algorithms based on MARSIS subsurface data, with modeling and with modeling ionospheric distortion <span class="hlt">TEC</span> reconstruction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA51B2399C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA51B2399C"><span>Analysis of Total Electron Content and Electron Density Profile during Different Geomagnetic Storms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chapagain, N. P.; Rana, B.; Adhikari, B.</p> <p>2017-12-01</p> <p>Total Electron content (<span class="hlt">TEC</span>) and electron density are the key parameters in the mitigation of ionospheric effects on radio communication system. Detail study of the <span class="hlt">TEC</span> and electron density variations has been carried out during geomagnetic storms, with longitude and latitude, for four different locations: (13˚N -17˚N, 88˚E -98˚E), (30˚N-50˚N, 120˚W -95˚W), (29˚S-26˚S, 167˚W-163˚W,) and (60˚S-45˚S, 120˚W-105˚W) using the Gravity Recovery and Climate Experiment (GRACE) satellite observations. In order to find the geomagnetic activity, the solar wind parameters such as north-south component of inter planetary magnetic field (Bz), plasma drift velocity (Vsw), flow pressure (nPa), AE, Dst and Kp indices were obtained from Operating Mission as Nodes on the Internet (OMNI) web system. The data for geomagnetic indices have been correlated with the <span class="hlt">TEC</span> and electron density for four different events of geomagnetic storms on 6 April 2008, 27 March 2008, 4 September 2008, and 11 October 2008. The result illustrates that the observed <span class="hlt">TEC</span> and electron density profile significantly vary with longitudes and latitudes. This study illustrates that the values of <span class="hlt">TEC</span> and the vertical electron density profile are influenced by the solar wind parameters associated with solar activities. The peak values of electron density and <span class="hlt">TEC</span> increase as the geomagnetic storms become stronger. Similarly, the electron density profile varies with altitudes, which peaks around the altitude range of about 250- 350 km, depending on the strength of geomagnetic storms. The results clearly show that the peak electron density shifted to higher altitude (from about 250 km to 350 km) as the geomagnetic disturbances becomes stronger.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSH11C2269B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSH11C2269B"><span>Empirical forecast of the quiet time Ionosphere over Europe: a comparative model investigation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Badeke, R.; Borries, C.; Hoque, M. M.; Minkwitz, D.</p> <p>2016-12-01</p> <p>The purpose of this work is to find the best empirical model for a reliable 24 hour forecast of the ionospheric Total Electron Content (<span class="hlt">TEC</span>) over Europe under geomagnetically quiet conditions. It will be used as an improved reference for the description of storm-induced perturbations in the ionosphere. The observational <span class="hlt">TEC</span>-data were obtained from the International GNSS Service (IGS). Four different forecast model approaches were validated with observational IGS <span class="hlt">TEC</span>-data: a 27 day median model (27d), a Fourier Analysis (FA) approach, the Neustrelitz <span class="hlt">TEC</span> global model (NTCM-GL) and NeQuick 2. Two years were investigated depending on the solar activity: 2015 (high activity) and 2008 (low avtivity) The time periods of magnetic storms, which were identified with the Dst index, were excluded from the validation. For both years the two models 27d and FA show better results than NTCM-GL and NeQuick 2. For example for the year 2015 and 15° E / 50° N the difference between the IGS data and the predicted 27d model shows a mean value of 0.413 <span class="hlt">TEC</span> units (TECU), a standard deviation of 3.307 TECU and a correlation coefficient of 0.921, while NTCM-GL and NeQuick 2 have mean differences of around 2-3 TECU, standard deviations of 4.5-5 TECU and correlation coefficients below 0.85. Since 27d and FA predictions strongly depend on observational data, the results confirm that data driven forecasts perform better than the climatological models NTCM-GL and NeQuick 2. However, the benefits of NTCM-GL and NeQuick 2 are actually the lower data dependency, i.e. they do not lack on precision when observational IGS <span class="hlt">TEC</span> data are unavailable. Hence a combination of the different models is recommended reacting accordingly to the different data availabilities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21439726','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21439726"><span>Cancer Health Empowerment for Living without Pain (Ca-HELP): effects of a tailored education and coaching intervention on pain and impairment.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kravitz, Richard L; Tancredi, Daniel J; Grennan, Tim; Kalauokalani, Donna; Street, Richard L; Slee, Christina K; Wun, Ted; Oliver, Jennifer Wright; Lorig, Kate; Franks, Peter</p> <p>2011-07-01</p> <p>We aimed to determine the effectiveness of a lay-administered tailored education and coaching (<span class="hlt">TEC</span>) intervention (aimed at reducing pain misconceptions and enhancing self-efficacy for communicating with physicians) on cancer pain severity, pain-related impairment, and quality of life. Cancer patients with baseline "worst pain" of ≥4 on a 0-10 scale or at least moderate functional impairment due to pain were randomly assigned to <span class="hlt">TEC</span> or enhanced usual care (EUC) during a telephone interview conducted in advance of a planned oncology office visit (265 patients randomized to <span class="hlt">TEC</span> or EUC; 258 completed at least one follow-up). Patients completed questionnaires before and after the visit and were interviewed by telephone at 2, 6, and 12 weeks. Mixed effects regressions were used to evaluate the intervention adjusting for patient, practice, and site characteristics. Compared to EUC, <span class="hlt">TEC</span> was associated with increased pain communication self-efficacy after the intervention (P<.001); both groups showed significant (P<.0001), similar, reductions in pain misconceptions. At 2 weeks, assignment to <span class="hlt">TEC</span> was associated with improvement in pain-related impairment (-0.25 points on a 5-point scale, 95% confidence interval -0.43 to -0.06, P=.01) but not in pain severity (-0.21 points on an 11-point scale, -0.60 to 0.17, P=.27). The improvement in pain-related impairment was not sustained at 6 and 12 weeks. There were no significant intervention by subgroup interactions (P>.10). We conclude that <span class="hlt">TEC</span>, compared with EUC, resulted in improved pain communication self-efficacy and temporary improvement in pain-related impairment, but no improvement in pain severity. Copyright © 2011 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17162372','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17162372"><span>The Wnt signaling antagonist Kremen1 is required for development of thymic architecture.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Osada, Masako; Ito, Emi; Fermin, Hector A; Vazquez-Cintron, Edwin; Venkatesh, Tadmiri; Friedel, Roland H; Pezzano, Mark</p> <p>2006-01-01</p> <p>Wnt signaling has been reported to regulate thymocyte proliferation and selection at several stages during T cell ontogeny, as well as the expression of FoxN1 in thymic epithelial cells (<span class="hlt">TECs</span>). Kremen1 (Krm1) is a negative regulator of the canonical Wnt signaling pathway, and functions together with the secreted Wnt inhibitor Dickkopf (Dkk) by competing for the lipoprotein receptor-related protein (LRP)-6 co-receptor for Wnts. Here krm1 knockout mice were used to examine krm1 expression in the thymus and its function in thymocyte and <span class="hlt">TEC</span> development. Krm1 expression was detected in both cortical and medullary <span class="hlt">TEC</span> subsets, as well as in immature thymocyte subsets, beginning at the CD25+CD44+ (DN2) stage and continuing until the CD4+CD8+(DP) stage. Neonatal mice show elevated expression of krm1 in all <span class="hlt">TEC</span> subsets. krm1(-/-) mice exhibit a severe defect in thymic cortical architecture, including large epithelial free regions. Much of the epithelial component remains at an immature Keratin 5+ (K5) Keratin 8(+)(K8) stage, with a loss of defined cortical and medullary regions. A TOPFlash assay revealed a 2-fold increase in canonical Wnt signaling in <span class="hlt">TEC</span> lines derived from krm1(-/-) mice, when compared with krm1(+/+) derived <span class="hlt">TEC</span> lines. Fluorescence activated cell sorting (FACS) analysis of dissociated thymus revealed a reduced frequency of both cortical (BP1(+)EpCAM(+)) and medullary (UEA-1(+) EpCAM(hi)) epithelial subsets, within the krm1(-/-) thymus. Surprisingly, no change in thymus size, total thymocyte number or the frequency of thymocyte subsets was detected in krm1(-/-) mice. However, our data suggest that a loss of Krm1 leads to a severe defect in thymic architecture. Taken together, this study revealed a new role for Krm1 in proper development of thymic epithelium.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28416305','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28416305"><span>Fracture Strength of Endodontically Treated Teeth with Different Access Cavity Designs.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Plotino, Gianluca; Grande, Nicola Maria; Isufi, Almira; Ioppolo, Pietro; Pedullà, Eugenio; Bedini, Rossella; Gambarini, Gianluca; Testarelli, Luca</p> <p>2017-06-01</p> <p>The purpose of this study was to compare in vitro the fracture strength of root-filled and restored teeth with traditional endodontic cavity (<span class="hlt">TEC</span>), conservative endodontic cavity (CEC), or ultraconservative "ninja" endodontic cavity (NEC) access. Extracted human intact maxillary and mandibular premolars and molars were selected and assigned to control (intact teeth), <span class="hlt">TEC</span>, CEC, or NEC groups (n = 10/group/type). Teeth in the <span class="hlt">TEC</span> group were prepared following the principles of traditional endodontic cavities. Minimal CECs and NECs were plotted on cone-beam computed tomographic images. Then, teeth were endodontically treated and restored. The 160 specimens were then loaded to fracture in a mechanical material testing machine (LR30 K; Lloyd Instruments Ltd, Fareham, UK). The maximum load at fracture and fracture pattern (restorable or unrestorable) were recorded. Fracture loads were compared statistically, and the data were examined with analysis of variance and the Student-Newman-Keuls test for multiple comparisons. The mean load at fracture for <span class="hlt">TEC</span> was significantly lower than the one for the CEC, NEC, and control groups for all types of teeth (P < .05), whereas no difference was observed among CEC, NEC, and intact teeth (P > .05). Unrestorable fractures were significantly more frequent in the <span class="hlt">TEC</span>, CEC, and NEC groups than in the control group in each tooth type (P < .05). Teeth with <span class="hlt">TEC</span> access showed lower fracture strength than the ones prepared with CEC or NEC. Ultraconservative "ninja" endodontic cavity access did not increase the fracture strength of teeth compared with the ones prepared with CEC. Intact teeth showed more restorable fractures than all the prepared ones. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23810989','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23810989"><span>Prostaglandin E(2) and insulin-like growth factor I interact to enhance proliferation of theca externa cells from chicken prehierarchical follicles.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jia, Yudong; Lin, Jinxing; Mi, Yuling; Zhang, Caiqiao</p> <p>2013-10-01</p> <p>The interactive effect of insulin-like growth factor I (IGF-I) and prostaglandin E2 (PGE2) on the proliferation of theca externa cells (<span class="hlt">TECs</span>) was investigated in the prehierarchical small yellow follicles of laying hens. IGF-I manifested a proliferating effect like PGE2 on <span class="hlt">TECs</span>, but this stimulating effect was restrained by AG1024 (IGF-IR inhibitor), KP372-1 (PKB/AKT inhibitor) or NS398 (COX-2 inhibitor). AG1024, KP372-1 or NS398 abolished IGF-I-stimulated COX-2 expression and PGE2 production. Meanwhile, KP372-1, NS398 or AG1024 depressed the PGE2-stimulated expression of COX-2 and IGF-IR mRNA. Therefore, the IGF-I receptor pathway up-regulates COX-2 expression and PGE2 synthesis via PKB signaling cascade, and then PGE2 stimulates IGF-IR mRNA expression to promote <span class="hlt">TEC</span> proliferation in an autocrine pattern. Overall, the reciprocal stimulation of intracellular PGE2 and IGF-I may enhance <span class="hlt">TEC</span> proliferation and facilitate the development of chicken prehierarchical follicles. Copyright © 2013 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29162898','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29162898"><span>Equivalent model optimization with cyclic correction approximation method considering parasitic effect for thermoelectric coolers.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Ning; Chen, Jiajun; Zhang, Kun; Chen, Mingming; Jia, Hongzhi</p> <p>2017-11-21</p> <p>As thermoelectric coolers (<span class="hlt">TECs</span>) have become highly integrated in high-heat-flux chips and high-power devices, the parasitic effect between component layers has become increasingly obvious. In this paper, a cyclic correction method for the <span class="hlt">TEC</span> model is proposed using the equivalent parameters of the proposed simplified model, which were refined from the intrinsic parameters and parasitic thermal conductance. The results show that the simplified model agrees well with the data of a commercial <span class="hlt">TEC</span> under different heat loads. Furthermore, the temperature difference of the simplified model is closer to the experimental data than the conventional model and the model containing parasitic thermal conductance at large heat loads. The average errors in the temperature difference between the proposed simplified model and the experimental data are no more than 1.6 K, and the error is only 0.13 K when the absorbed heat power Q c is equal to 80% of the maximum achievable absorbed heat power Q max . The proposed method and model provide a more accurate solution for integrated <span class="hlt">TECs</span> that are small in size.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AdSpR..52.1125T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AdSpR..52.1125T"><span>A real-time ionospheric model based on GNSS Precise Point Positioning</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tu, Rui; Zhang, Hongping; Ge, Maorong; Huang, Guanwen</p> <p>2013-09-01</p> <p>This paper proposes a method of real-time monitoring and modeling the ionospheric Total Electron Content (<span class="hlt">TEC</span>) by Precise Point Positioning (PPP). Firstly, the ionospheric <span class="hlt">TEC</span> and receiver’s Differential Code Biases (DCB) are estimated with the undifferenced raw observation in real-time, then the ionospheric <span class="hlt">TEC</span> model is established based on the Single Layer Model (SLM) assumption and the recovered ionospheric <span class="hlt">TEC</span>. In this study, phase observations with high precision are directly used instead of phase smoothed code observations. In addition, the DCB estimation is separated from the establishment of the ionospheric model which will limit the impacts of the SLM assumption impacts. The ionospheric model is established at every epoch for real time application. The method is validated with three different GNSS networks on a local, regional, and global basis. The results show that the method is feasible and effective, the real-time ionosphere and DCB results are very consistent with the IGS final products, with a bias of 1-2 TECU and 0.4 ns respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040074259','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040074259"><span>Testing of a Miniature Loop Heat Pipe Using a Thermal Electrical Cooler for Temperature Control</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ku, Jentung; Jeong, Soeng-II; Butler, Dan</p> <p>2004-01-01</p> <p>This paper describes the design and testing of a miniature LHP having a 7 mm O.D. evaporator with an integral CC. The vapor line and liquid line are made of 1.6mm stainless steel tubing. The evaporator and the CC are connected on the outer surface by a copper strap and a thermoelectric (<span class="hlt">TEC</span>) is installed on the strap. The <span class="hlt">TEC</span> is used to control the CC temperature by applying an electrical current for heating or cooling. Tests performed in ambient included start-up, power cycle, sink temperature cycle, and CC temperature control using <span class="hlt">TEC</span>. The LHP demonstrated very robust operation in all tests where the heat load varied between 0.5W and 1OOW, and the sink temperature varied between 243K and 293K. The heat leak from the evaporator to the CC was extremely small. The <span class="hlt">TEC</span> was able to control the CC temperature within +/-0.3K under all test conditions, and the required control heater power was less than 1W.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AdSpR..39.1292N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AdSpR..39.1292N"><span>Use of total electron content data to analyze ionosphere electron density gradients</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nava, B.; Radicella, S. M.; Leitinger, R.; Coïsson, P.</p> <p></p> <p>In the presence of electron density gradients the thin shell approximation for the ionosphere, used together with a simple mapping function to convert slant total electron content (<span class="hlt">TEC</span>) to vertical <span class="hlt">TEC</span>, could lead to <span class="hlt">TEC</span> conversion errors. These "mapping function errors" can therefore be used to detect the electron density gradients in the ionosphere. In the present work GPS derived slant <span class="hlt">TEC</span> data have been used to investigate the effects of the electron density gradients in the middle and low latitude ionosphere under geomagnetic quiet and disturbed conditions. In particular the data corresponding to the geographic area of the American Sector for the days 5-7 April 2000 have been used to perform a complete analysis of mapping function errors based on the "coinciding pierce point technique". The results clearly illustrate the electron density gradient effects according to the locations considered and to the actual levels of disturbance of the ionosphere. In addition, the possibility to assess an ionospheric shell height able to minimize the mapping function errors has been verified.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20060036540&hterms=GIM+TEC+Map&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DGIM%2BTEC%2BMap','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20060036540&hterms=GIM+TEC+Map&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DGIM%2BTEC%2BMap"><span>Global Ionosphere Perturbations Monitored by the Worldwide GPS Network</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ho, C. M.; Manucci, A. T.; Lindqwister, U. J.; Pi, X.</p> <p>1996-01-01</p> <p>For the first time, measurements from the Global Positioning System (GPS) worldwide network are employed to study the global ionospheric total electron content(<span class="hlt">TEC</span>) changes during a magnetic storm (November 26, 1994). These measurements are obtained from more than 60 world-wide GPS stations which continuously receive dual-frequency signals. Based on the delays of the signals, we have generated high resolution global ionospheric maps (GIM) of <span class="hlt">TEC</span> at 15 minute intervals. Using a differential method comparing storm time maps with quiet time maps, we find that significant <span class="hlt">TEC</span> increases (the positive effect ) are the major feature in the winter hemisphere during this storm (the maximum percent change relative to quiet times is about 150 percent).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20060051817&hterms=behavior+modification&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dbehavior%2Bmodification','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20060051817&hterms=behavior+modification&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dbehavior%2Bmodification"><span>Ionospheric Behavior During the First Few Hours of Intense Geomagnetic Storms</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mannucci, Anthony J.; Crowley, Geoff; Tsurutani, Bruce; Fuller-Rowell, Tim</p> <p>2006-01-01</p> <p>The behavior of the ionosphere during the first few hours of intense geomagnetic storms is presented. The topics include: 1) <span class="hlt">TEC</span> Modification; 2) JASON <span class="hlt">TEC</span> (1336 km altitude); 3) Multiple Storms; 4) CHAMP (greater than 400 km) November 20, 2003; 5) November 20, 1PM LT, Ground; 6) Role of Modeling; and 7) Composition-related increase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED430085.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED430085.pdf"><span>Generic Workplace Skills for Job Application, Employment Retention, and Career Promotion in Today's Economic Environment.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Broadbent, William A.</p> <p></p> <p>A study used the Vocational-Technical Education Consortium of States (V-<span class="hlt">TECS</span>) workplace skills inventory in a validation exercise for use of the inventory in Hawaii. A facilitator reduced the size of the V-<span class="hlt">TECS</span> instrument. The resulting document was tested using several colleagues of the principal investigator before it was used in the field. The…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008APS..NWS.F1003S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008APS..NWS.F1003S"><span>The role of physics departments in the recruitment, preparation and support of pre-college teachers of physics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Seeley, Lane</p> <p>2008-05-01</p> <p>The United States faces a critical shortage of qualified physics and physical science teachers. The number of high school students taking physics is increasing but the number of physics majors pursuing careers in pre-college teaching is not nearly sufficient to meet the demand. College and university physics departments have content expertise and ready access to potential future teachers of physics. In order to address the crisis in physics and physical science education, APS, AAPT, and AIP have developed the Phys<span class="hlt">TEC</span> project. Seattle Pacific University is one of six fully funded Phys<span class="hlt">TEC</span> sites. The Phys<span class="hlt">TEC</span> project also supports a coalition of more than one hundred institutions that are committed to improving K-12 physics and physical science education. This talk will describe the national Phys<span class="hlt">TEC</span> project along with our local Phys<span class="hlt">TEC</span> program. We will explore ways in which physics departments can more fully integrate the preparation of pre-college physics teachers within existing departmental priorities. We will discuss opportunities for regional partnerships between 2-year and 4-year colleges, school districts, and teacher preparation programs. We will also highlight ways in which our research on the learning and teaching of physics informs the development of tools that teachers and teacher educators can use to diagnose student ideas and to design subsequent instruction that capitalizes on these ideas. In collaboration with Stamatis Vokos, Seattle Pacific University and Pam Kraus, Facet Innovations LLC.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/527783','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/biblio/527783"><span>Fiber optic assembly and method of making same</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Kramer, D.P.; Beckman, T.M.</p> <p>1997-09-02</p> <p>There is provided an assembly having a light guiding medium sealed to a holder. Preferably the holder is a metal shell and a light guiding medium is an optical fiber of glass or sapphire whisker. The assembly includes a sealing medium which sealingly engages the metal holder to the fiber. In the formation of the assembly, the seal is essentially hermetic having a capability of minimizing leakage having a helium leak rate of less than 1{times}10{sup {minus}8} cubic centimeters per second and high strength having a capability of withstanding pressures of 100,000 psi or greater. The features of the assembly are obtained by a specific preparation method and by selection of specific starting materials. The fiber is selected to have a sufficiently high coefficient of thermal expansion which minimizes strains in the component during fabrication, as a result of fabrication, and during use. The other components are selected to be of a material having compatible coefficients of thermal expansion (<span class="hlt">TEC</span>) where the <span class="hlt">TEC</span> of the holder is greater than or equal to the <span class="hlt">TEC</span> of the sealing material. The <span class="hlt">TEC</span> of the sealing material is in turn greater than or equal to the <span class="hlt">TEC</span> of the fiber. It is preferred that the materials be selected so that their respective coefficients of thermal expansion are as close as possible to one another and they may all be equal. 4 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007JGRA..11212305L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007JGRA..11212305L"><span>Longitudinal structure of the equatorial ionosphere: Time evolution of the four-peaked EIA structure</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lin, C. H.; Hsiao, C. C.; Liu, J. Y.; Liu, C. H.</p> <p>2007-12-01</p> <p>Longitudinal structure of the equatorial ionosphere during the 24 h local time period is observed by the FORMOSAT-3/COSMIC (F3/C) satellite constellation. By binning the F3/C radio occultation observations during September and October 2006, global ionospheric total electron content (<span class="hlt">TEC</span>) maps at a constant local time map (local time <span class="hlt">TEC</span> map, referred as LT map) can be obtained to monitor the development and subsidence of the four-peaked longitudinal structure of the equatorial ionosphere. From LT maps, the four-peaked structure starts to develop at 0800-1000 LT and becomes most prominent at 1200-1600 LT. The longitudinal structure starts to subside after 2200-2400 LT and becomes indiscernible after 0400-0600 LT. In addition to <span class="hlt">TEC</span>, ionospheric peak altitude also shows a four-peaked longitudinal structure with variation very similar to <span class="hlt">TEC</span> during daytime. The four-peaked structure of the ionospheric peak altitude is indiscernible at night. With global local time maps of ionospheric <span class="hlt">TEC</span> and peak altitude, we compare temporal variations of the longitudinal structure with variations of E × B drift from the empirical model. Our results indicate that the observations are consistent with the hypothesis that the four-peaked longitudinal structure is caused by the equatorial plasma fountain modulated by the E3 nonmigrating tide. Additionally, the four maximum regions show a tendency of moving eastward with propagation velocity of several 10 s m/s.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1353107-back-gated-graphene-anode-more-efficient-thermionic-energy-converters','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1353107-back-gated-graphene-anode-more-efficient-thermionic-energy-converters"><span>Back-gated graphene anode for more efficient thermionic energy converters</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Yuan, Hongyuan; Riley, Daniel C.; Shen, Zhi-Xun; ...</p> <p>2016-12-15</p> <p>Thermionic energy converters (<span class="hlt">TECs</span>) are a direct heat-to-electricity conversion technology with great potential for high efficiency and scalability. However, space charge barrier in the inter-electrode gap and high anode work function are major obstacles toward realizing high efficiency. Here, we demonstrate for the first time a prototype <span class="hlt">TEC</span> using a back-gated graphene anode, a barium dispenser cathode, and a controllable inter-electrode gap as small as 17 µm, which simultaneously addresses these two obstacles. This leads to an electronic conversion efficiency of 9.8% at cathode temperature of 1000 °C, the highest reported by far. We first demonstrate that electrostatic gating ofmore » graphene by a 20 nm HfO 2 dielectric layer changes the graphene anode work function by 0.63 eV, as observed from the current-voltage characteristics of the <span class="hlt">TEC</span>. Next, we show that the efficiency increases by a factor of 30.6 by reducing the gap from 1 mm down to 17 µm, after a mono-layer of Ba is deposited on graphene by the dispenser cathode. Lastlu, we show that electrostatic gating of graphene further reduces the graphene work function from 1.85 to 1.69 eV, leading to an additional 67% enhancement in <span class="hlt">TEC</span> efficiency. Note that the overall efficiency using the back-gated graphene anode is 6.7 times higher compared with that of a <span class="hlt">TEC</span> with a tungsten anode and the same inter-electrode gap.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..121.5880S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..121.5880S"><span>Effects of ionizing energetic electrons and plasma transport in the ionosphere during the initial phase of the December 2006 magnetic storm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Suvorova, A. V.; Huang, C.-M.; Dmitriev, A. V.; Kunitsyn, V. E.; Andreeva, E. S.; Nesterov, I. A.; Klimenko, M. V.; Klimenko, V. V.; Tumanova, Yu. S.</p> <p>2016-06-01</p> <p>The initial phase of a major geomagnetic storm on 14 December 2006 was selected in order to investigate the ionizing effect of energetic electrons in the ionosphere. The global network of GPS receivers was used to analyze the total electron content (<span class="hlt">TEC</span>). A strong positive ionospheric storm of ~20 <span class="hlt">TEC</span> units (TECU) with ~6 h duration was observed on the dayside during the interval of northward interplanetary magnetic field. At the same time, the NOAA/POES satellites observed long-lasting intense fluxes of >30 keV electrons in the topside ionosphere at middle and low latitudes, including a near-equatorial forbidden zone outside of the South Atlantic Anomaly (SAA). We found that the <span class="hlt">TEC</span> increases overlapped well with the enhancements of energetic electrons. Modeling of the ionospheric response by using a Global Self-consistent Model of the Thermosphere, Ionosphere, and Protonosphere, based on the standard mechanisms of plasma transport, could only partially explain the ionospheric response and was unable to predict the long-duration increase of <span class="hlt">TEC</span>. For the energetic electrons, we estimated the ionizing effect of ~45 TECU and ~23 TECU in the topside ionosphere, respectively, inside and outside of SAA. The ionizing effect contributed from 50% to 100% of <span class="hlt">TEC</span> increases and provided the long duration and wide latitudinal extension of the positive ionospheric storm. This finding is a very important argument in supporting significant ionizing effect of energetic electrons in the storm time ionosphere both at middle and low latitudes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1353107','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1353107"><span>Back-gated graphene anode for more efficient thermionic energy converters</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Yuan, Hongyuan; Riley, Daniel C.; Shen, Zhi-Xun</p> <p></p> <p>Thermionic energy converters (<span class="hlt">TECs</span>) are a direct heat-to-electricity conversion technology with great potential for high efficiency and scalability. However, space charge barrier in the inter-electrode gap and high anode work function are major obstacles toward realizing high efficiency. Here, we demonstrate for the first time a prototype <span class="hlt">TEC</span> using a back-gated graphene anode, a barium dispenser cathode, and a controllable inter-electrode gap as small as 17 µm, which simultaneously addresses these two obstacles. This leads to an electronic conversion efficiency of 9.8% at cathode temperature of 1000 °C, the highest reported by far. We first demonstrate that electrostatic gating ofmore » graphene by a 20 nm HfO 2 dielectric layer changes the graphene anode work function by 0.63 eV, as observed from the current-voltage characteristics of the <span class="hlt">TEC</span>. Next, we show that the efficiency increases by a factor of 30.6 by reducing the gap from 1 mm down to 17 µm, after a mono-layer of Ba is deposited on graphene by the dispenser cathode. Lastlu, we show that electrostatic gating of graphene further reduces the graphene work function from 1.85 to 1.69 eV, leading to an additional 67% enhancement in <span class="hlt">TEC</span> efficiency. Note that the overall efficiency using the back-gated graphene anode is 6.7 times higher compared with that of a <span class="hlt">TEC</span> with a tungsten anode and the same inter-electrode gap.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26013993','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26013993"><span>Effect of a Novel Interdisciplinary Teaching Program in the Care-continuum on Medical Student Knowledge and Self-Efficacy.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lathia, Amanda; Rothberg, Michael; Heflin, Mitchell; Nottingham, Kelly; Messinger-Rapport, Barbara</p> <p>2015-10-01</p> <p>Medical students report that they receive inadequate training in different levels of care, including care transitions to and from post-acute (PA) and long-term care (LTC). The authors implemented the Medical Students as Teachers in Extended Care (Med<span class="hlt">TEC</span>) program as an educational innovation at the Cleveland Clinic to address training in the care-continuum, as well as the new medical student and physician competencies in PA/LTC. Med<span class="hlt">TEC</span> is a 7-hour interactive program that supplements standard geriatric didactics during the medical student primary care rotation. This study evaluated the performance of the program in improving medical student knowledge and attitudes on levels and transitions of care. The program occurs in a community facility that includes subacute/skilled nursing, assisted living, and nursing home care. Five to 8 students completing their primary care rotation at the Cleveland Clinic are required to participate in the Med<span class="hlt">TEC</span> program each month. The program includes up to 3 hours of interactive discussion and opportunities to meet facility staff, residents, and patients. The highlight of the program is a student-led in-service for facility staff. With institutional review board approval as an exempt educational research project, pre- and postactivity surveys assessed self-efficacy and knowledge regarding levels of care for students who participated in the program and a student comparison group. The post-program knowledge test also was administered to hospital medicine staff, and test performance was compared with medical students who participated in the Med<span class="hlt">TEC</span> program. Between October 2011 and December 2013, approximately 100 students participated in 20 sessions of Med<span class="hlt">TEC</span>. All students reported improved self-efficacy and attitudes regarding care of older adults and care transition management. Mean percentage correct on the knowledge test increased significantly from 59.8% to 71.2% (P = .004) for the Med<span class="hlt">TEC</span> participants but not for the comparison group</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2011/5097/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2011/5097/"><span>Assessment of selected contaminants in streambed- and suspended-sediment samples collected in Bexar County, Texas, 2007-09</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wilson, Jennifer T.</p> <p>2011-01-01</p> <p>Elevated concentrations of sediment-associated contaminants are typically associated with urban areas such as San Antonio, Texas, in Bexar County, the seventh most populous city in the United States. This report describes an assessment of selected sediment-associated contaminants in samples collected in Bexar County from sites on the following streams: Medio Creek, Medina River, Elm Creek, Martinez Creek, Chupaderas Creek, Leon Creek, Salado Creek, and San Antonio River. During 2007-09, the U.S. Geological Survey periodically collected surficial streambed-sediment samples during base flow and suspended-sediment (large-volume suspended-sediment) samples from selected streams during stormwater runoff. All sediment samples were analyzed for major and trace elements and for organic compounds including halogenated organic compounds and polycyclic aromatic hydrocarbons (PAHs). Selected contaminants in streambed and suspended sediments in watersheds of the eight major streams in Bexar County were assessed by using a variety of methods—observations of occurrence and distribution, comparison to sediment-quality guidelines and data from previous studies, statistical analyses, and source indicators. Trace elements concentrations were low compared to the consensus-based sediment-quality guidelines threshold effect concentration (<span class="hlt">TEC</span>) and probable effect concentration (PEC). Trace element concentrations were greater than the <span class="hlt">TEC</span> in 28 percent of the samples and greater than the PEC in 1.5 percent of the samples. Chromium concentrations exceeded sediment-quality guidelines more frequently than concentrations of any other constituents analyzed in this study (greater than the <span class="hlt">TEC</span> in 69 percent of samples and greater than the PEC in 8 percent of samples). Mean trace element concentrations generally are lower in Bexar County samples compared to concentrations in samples collected during previous studies in the Austin and Fort Worth, Texas, areas, but considering the relatively</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016OAP....29..136P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016OAP....29..136P"><span>Virtual Observatory and Colitec Software: Modules, Features, Methods</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pohorelov, A. V.; Khlamov, S. V.; Savanevych, V. E.; Briukhovetskyi, A. B.; Vlasenko, V. P.</p> <p></p> <p>In this article we described complex processing system created by the CoLi<span class="hlt">Tec</span> project. This system includes features, user-friendly tools for processing control, results reviewing, integration with online catalogs and a lot of different computational modules that are based on the developed methods. Some of them are described in the article.The main directions of the CoLi<span class="hlt">Tec</span> software development are the Virtual Observatory, software for automated asteroids and comets detection and software for brightness equalization.The CoLi<span class="hlt">Tec</span> software is widely used in a number of observatories in the CIS. It has been used in about 700 000 observations, during which 1560 asteroids, including 5 NEO, 21 Trojan asteroids of Jupiter, 1 Centaur and four comets were discovered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011RaSc...46.2005D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011RaSc...46.2005D"><span>Two-dimensional ionospheric tomography over the low-latitude Indian region: An intercomparison of ART and MART algorithms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Das, Sukanta Kumar; Shukla, Ashish Kumar</p> <p>2011-04-01</p> <p>Single-frequency users of a satellite-based augmentation system (SBAS) rely on ionospheric models to mitigate the delay due to the ionosphere. The ionosphere is the major source of range and range rate errors for users of the Global Positioning System (GPS) who require high-accuracy positioning. The purpose of the present study is to develop a tomography model to reconstruct the total electron content (<span class="hlt">TEC</span>) over the low-latitude Indian region which lies in the equatorial ionospheric anomaly belt. In the present study, the <span class="hlt">TEC</span> data collected from the six <span class="hlt">TEC</span> collection stations along a longitudinal belt of around 77 degrees are used. The main objective of the study is to find out optimum pixel size which supports a better reconstruction of the electron density and hence the <span class="hlt">TEC</span> over the low-latitude Indian region. Performance of two reconstruction algorithms Algebraic Reconstruction Technique (ART) and Multiplicative Algebraic Reconstruction Technique (MART) is analyzed for different pixel sizes varying from 1 to 6 degrees in latitude. It is found from the analysis that the optimum pixel size is 5° × 50 km over the Indian region using both ART and MART algorithms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28250264','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28250264"><span>Methicillin-Susceptible Teicoplanin-Resistant Staphylococcus haemolyticus Isolate from a Bloodstream Infection with Novel Mutations in the tcaRAB Teicoplanin Resistance Operon.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bakthavatchalam, Yamuna Devi; Sudarsanam, Thambu David; Babu, Priyanka; Munuswamy, Elakkiya; Muthuirulandi Sethuvel, Dhiviya Prabaa; Devanga Ragupathi, Naveen Kumar; Veeraraghavan, Balaji</p> <p>2017-07-24</p> <p>Staphylococcus haemolyticus is a coagulase-negative staphylococcus that is frequently isolated from blood cultures. Here, we report a case of methicillin-susceptible S. haemolyticus that is resistant to teicoplanin (<span class="hlt">TEC</span>) and heteroresistant to vancomycin (VAN). The isolate was susceptible to cefoxitin and resistant to <span class="hlt">TEC</span> by Etest. Population analysis profile-area under the curve analysis confirmed the presence of a VAN heteroresistant subpopulation. Next-generation sequencing analysis of the genome revealed the presence of blaZ and msr(A), which encode cross-resistance to macrolide, lincosamide, and streptogramin B, and the quinolone resistance-conferring gene norA. In addition, several amino acid substitutions were observed in the <span class="hlt">TEC</span> resistance operon tcaRAB, including I3N, I390N, and L450I in tcaA and L44V, G52V, and S87P in tcaR, as well as in the transpeptidase encoding gene walK (D336Y, R375L, and V404A) and L315 and P316 in graS. We hypothesized that this combination of mutations could confer <span class="hlt">TEC</span> resistance and reduced VAN susceptibility.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.G53B0714D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.G53B0714D"><span>Meteorology and GNSS? What is the benefit?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Drummond, P.; Grünig, S.</p> <p>2010-12-01</p> <p>Due to the strong correlation between water vapor in the atmosphere and GNSS tropospheric propagation delays, we can estimate the Integrated Precipitable Water Vapor (IPWV) in the atmosphere through GNSS measurements. This parameter is crucial for meteorologists as the water content in the atmosphere is a key parameter in the weather models. The Total Electron Content (<span class="hlt">TEC</span>) in the ionosphere has a huge impact on the ionospheric propagation delay in GNSS signals. By computing the ionospheric delay from GNSS measurements it is possible to predict the <span class="hlt">TEC</span> which is an excellent indicator for ionospheric activity. The benefit is that we can estimate the influence on the RTK performance from <span class="hlt">TEC</span> values. The atmospheric feature in the Trimble Atmosphere App (as well as in VRSNet software) allows computing both IPWV and <span class="hlt">TEC</span> values from a CORS network. IPWV is computed using surface meteorological data such as temperature and pressure as well as radiosonde data. The results are shown in a table like form as well as in numerous graphical forms such as contour and surface plots, station and condition charts. The computed values can be animated in a movie over the last 24 hours.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..MARF38006K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..MARF38006K"><span>High School Physics Teacher Outreach Programs at California State University Long Beach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kwon, Chuhee; Pickett, Galen; Henriques, Laura</p> <p>2013-03-01</p> <p>One of the goals of the CSULB Phys<span class="hlt">TEC</span> project has been to establish a physics teaching community that partners CSULB faculty, high school teachers, pre-service teachers, and physics students. In two years, we have created a solid sustainable Physics Teacher Network with local high school teachers. We will discuss the successful outreach programs for high school physics teachers at CSULB and the detailed logistics. Teacher-In-Residence (TIR), high school physics teachers working with the CSULB Phys<span class="hlt">TEC</span> team, has provided invaluable input for designing and implementing outreach events. The department organizes biannual open house for local high school teachers and their students. The open house event is attended by pre-service teachers, physics undergraduate and graduate students, and faculty. We also host the monthly demo-sharing day that physics teachers bring and share topical demos, which has about 30 - 50 attendees each month. The CSULB Phys<span class="hlt">TEC</span> project also distributes a monthly newsletter for local physics teachers with upcoming events and information about teaching, and this newsletter is organized and written by TIR. This work is supported by the Phys<span class="hlt">TEC</span> grant.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..12112104W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..12112104W"><span>Three-dimensional ionospheric tomography reconstruction using the model function approach in Tikhonov regularization</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Sicheng; Huang, Sixun; Xiang, Jie; Fang, Hanxian; Feng, Jian; Wang, Yu</p> <p>2016-12-01</p> <p>Ionospheric tomography is based on the observed slant total electron content (s<span class="hlt">TEC</span>) along different satellite-receiver rays to reconstruct the three-dimensional electron density distributions. Due to incomplete measurements provided by the satellite-receiver geometry, it is a typical ill-posed problem, and how to overcome the ill-posedness is still a crucial content of research. In this paper, Tikhonov regularization method is used and the model function approach is applied to determine the optimal regularization parameter. This algorithm not only balances the weights between s<span class="hlt">TEC</span> observations and background electron density field but also converges globally and rapidly. The background error covariance is given by multiplying background model variance and location-dependent spatial correlation, and the correlation model is developed by using sample statistics from an ensemble of the International Reference Ionosphere 2012 (IRI2012) model outputs. The Global Navigation Satellite System (GNSS) observations in China are used to present the reconstruction results, and measurements from two ionosondes are used to make independent validations. Both the test cases using artificial s<span class="hlt">TEC</span> observations and actual GNSS s<span class="hlt">TEC</span> measurements show that the regularization method can effectively improve the background model outputs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JAP...122b5109A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JAP...122b5109A"><span>Taguchi optimization of bismuth-telluride based thermoelectric cooler</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Anant Kishore, Ravi; Kumar, Prashant; Sanghadasa, Mohan; Priya, Shashank</p> <p>2017-07-01</p> <p>In the last few decades, considerable effort has been made to enhance the figure-of-merit (ZT) of thermoelectric (TE) materials. However, the performance of commercial TE devices still remains low due to the fact that the module figure-of-merit not only depends on the material ZT, but also on the operating conditions and configuration of TE modules. This study takes into account comprehensive set of parameters to conduct the numerical performance analysis of the thermoelectric cooler (<span class="hlt">TEC</span>) using a Taguchi optimization method. The Taguchi method is a statistical tool that predicts the optimal performance with a far less number of experimental runs than the conventional experimental techniques. Taguchi results are also compared with the optimized parameters obtained by a full factorial optimization method, which reveals that the Taguchi method provides optimum or near-optimum <span class="hlt">TEC</span> configuration using only 25 experiments against 3125 experiments needed by the conventional optimization method. This study also shows that the environmental factors such as ambient temperature and cooling coefficient do not significantly affect the optimum geometry and optimum operating temperature of <span class="hlt">TECs</span>. The optimum <span class="hlt">TEC</span> configuration for simultaneous optimization of cooling capacity and coefficient of performance is also provided.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/361917-consensus-sediment-quality-guidelines-polycyclic-aromatic-hydrocarbon-mixtures','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/361917-consensus-sediment-quality-guidelines-polycyclic-aromatic-hydrocarbon-mixtures"><span>Consensus sediment quality guidelines for polycyclic aromatic hydrocarbon mixtures</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Swartz, R.C.</p> <p>1999-04-01</p> <p>Sediment quality guidelines (SQGs) for polycyclic aromatic hydrocarbons (PAHs) have been derived from a variety of laboratory, field, and theoretical foundations. They include the screening level concentration, effects ranges-low and -median, equilibrium partitioning concentrations, apparent effects threshold, {Sigma}PAH model, and threshold and probable effects levels. The resolution of controversial differences among the PAH SQGs lies in an understanding of the effects of mixtures. Polycyclic aromatic hydrocarbons virtually always occur in field-collected sediment as a complex mixture of covarying compounds. When expressed as a mixture concentration, that is, total PAH (TPAH), the guidelines form three clusters that were intended in theirmore » original derivations to represent threshold (<span class="hlt">TEC</span> = 290 {micro}g/g organic carbon [OC]), median (MEC = 1,800 {micro}g/g OC), and extreme (EEC = 10,000 {micro}g/g OC) effects concentrations. The <span class="hlt">TEC</span>/MEC/EEC consensus guidelines provide a unifying synthesis of other SQGs, reflect causal rather than correlative effects, account for mixtures, and predict sediment toxicity and benthic community perturbations at sites of PAH contamination. The <span class="hlt">TEC</span> offers the most useful SQG because PAH mixtures are unlikely to cause adverse effects on benthic ecosystems below the <span class="hlt">TEC</span>.« less</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <div class="footer-extlink text-muted" style="margin-bottom:1rem; text-align:center;">Some links on this page may take you to non-federal websites. 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