28 results on '"Califf S"'
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2. Assessment of the Weimer Geomagnetic Perturbation Model for High‐Latitude Positioning and Navigation.
- Author
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Califf, S., Nair, M., Weimer, D., Zachman, N., and Poedjono, B.
- Subjects
GEOMAGNETIC variations ,MAGNETIC storms ,ENVIRONMENTAL sciences ,MAGNETIC declination ,MAGNETIC fields ,SOLAR wind ,GEOMAGNETISM - Abstract
The Geomagnetism Group at the National Centers for Environmental Information (NCEI), in collaboration with the Cooperative Institute for Research in Environmental Sciences (CIRES), along with various government and industry partners, specializes in developing and providing access to Earth's internal magnetic field models. These models are crucial for applications such as compass navigation and wellbore positioning, offering reference values for the geomagnetic field (total field, dip or inclination, and declination) at any location across the Earth. This study assesses the Weimer geomagnetic perturbation model, proposed by Weimer in 2013, which is an empirical model of magnetic field variations at high latitudes driven by solar wind measurements, as a candidate for capturing geomagnetic field variations in high‐latitude areas. We compare the geomagnetic field variations predicted by the Weimer model against data from the INTERMAGNET and SuperMAG observatory networks. Our findings indicate that the Weimer model achieves a reduction in the standard deviations of high‐latitude magnetic field variations by approximately 20%–30% once quiet‐time baselines are removed from the data set. Furthermore, we compare the performance of the Weimer model against the Space Weather Modeling Framework's Geospace model during specific geomagnetic storms in 2017 and 2018, and we find that the Weimer model is more effective in predicting magnetic variations at high latitudes than the Geospace model during these storms. Additionally, comparisons to magnetometer data collected from high‐latitude directional‐drilling operations align with the trends observed in comparisons with INTERMAGNET and SuperMAG observatory data, confirming the Weimer model's reliability and effectiveness for such applications. Plain Language Summary: The Geomagnetism Group at the National Centers for Environmental Information (NCEI), in collaboration with the Cooperative Institute for Research in Environmental Sciences (CIRES), along with various government and industry partners, develops geomagnetic models that are used for navigation and oil drilling applications. At high latitudes, geomagnetic variations caused by the interaction between the solar wind and the Earth's magnetic field increases uncertainty in the models. This study assesses the Weimer geomagnetic perturbation model as a candidate to compensate for these geomagnetic variations. We compare the model to scientific ground observatories, and show that the model captures 20%–30% of the variation. We also demonstrate that the model is useful in applied setting by comparing the model to data collected from oil drilling operations. Key Points: The Weimer Geomagnetic Perturbation Model is evaluated for real‐time prediction of geomagnetic disturbances at high latitudesThe Weimer model reduces geomagnetic reference errors at high latitudes by 20%–30% based on comparisons to observatory dataMeasurement‐while‐drilling data show that the Weimer model can save valuable rig time by reducing geomagnetic reference model errors [ABSTRACT FROM AUTHOR]
- Published
- 2024
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3. Role of Subauroral Polarization Streams in Deep Injections of Energetic Electrons Into the Inner Magnetosphere
- Author
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Goyal, R., primary, Zhao, H., additional, Califf, S., additional, Goldstein, J., additional, and Sarris, T. E., additional
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- 2024
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4. International Geomagnetic Reference Field: the thirteenth generation
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Alken, P., Thébault, E., Beggan, C. D., Amit, H., Aubert, J., Baerenzung, J., Bondar, T. N., Brown, W. J., Califf, S., Chambodut, A., Chulliat, A., Cox, G. A., Finlay, C. C., Fournier, A., Gillet, N., Grayver, A., Hammer, M. D., Holschneider, M., Huder, L., Hulot, G., Jager, T., Kloss, C., Korte, M., Kuang, W., Kuvshinov, A., Langlais, B., Léger, J.-M., Lesur, V., Livermore, P. W., Lowes, F. J., Macmillan, S., Magnes, W., Mandea, M., Marsal, S., Matzka, J., Metman, M. C., Minami, T., Morschhauser, A., Mound, J. E., Nair, M., Nakano, S., Olsen, N., Pavón-Carrasco, F. J., Petrov, V. G., Ropp, G., Rother, M., Sabaka, T. J., Sanchez, S., Saturnino, D., Schnepf, N. R., Shen, X., Stolle, C., Tangborn, A., Tøffner-Clausen, L., Toh, H., Torta, J. M., Varner, J., Vervelidou, F., Vigneron, P., Wardinski, I., Wicht, J., Woods, A., Yang, Y., Zeren, Z., and Zhou, B.
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- 2021
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5. Evaluation of candidate models for the 13th generation International Geomagnetic Reference Field
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Alken, P., Thébault, E., Beggan, C. D., Aubert, J., Baerenzung, J., Brown, W. J., Califf, S., Chulliat, A., Cox, G. A., Finlay, C. C., Fournier, A., Gillet, N., Hammer, M. D., Holschneider, M., Hulot, G., Korte, M., Lesur, V., Livermore, P. W., Lowes, F. J., Macmillan, S., Nair, M., Olsen, N., Ropp, G., Rother, M., Schnepf, N. R., Stolle, C., Toh, H., Vervelidou, F., Vigneron, P., and Wardinski, I.
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- 2021
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6. The effects of particle injections on the ring current development during the 7-8 September 2017 geomagnetic storm
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Ferradas, C. P., primary, Fok, M.-C., additional, Maruyama, N., additional, Henderson, M. G., additional, Califf, S., additional, Thaller, S. A., additional, and Kress, B. T., additional
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- 2023
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7. Long‐Term Bias Stability of the GOES‐NOP Magnetometers
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Califf, S., primary, Rich, F. J., additional, Loto'aniu, T. M., additional, Singer, H. J., additional, and Redmon, R. J., additional
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- 2023
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8. The GOES-16 Spacecraft Science Magnetometer
- Author
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Loto’aniu, T. M., Redmon, R. J., Califf, S., Singer, H. J., Rowland, W., Macintyre, S., Chastain, C., Dence, R., Bailey, R., Shoemaker, E., Rich, F. J., Chu, D., Early, D., Kronenwetter, J., and Todirita, M.
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- 2019
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9. Statistical Analysis of the Differential Deep Penetration of Energetic Electrons and Protons into the Low L Region ( L < 4)
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Zhao, H., primary, Califf, S. T., additional, Goyal, R., additional, Li, X., additional, Gkioulidou, M., additional, Manweiler, J. W., additional, and Krantz, S., additional
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- 2023
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10. Evaluation of the Weimer Model for real-time high-latitude magnetic field modeling
- Author
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Califf, S., Nair, M., Chulliat, A., and Weimer, D.
- Abstract
The geomagnetism group of NCEI/CIRES, in partnership with their government and industry partners, develops and distributes magnetic field models of the Earth’s internal field for applications such as navigation and directional drilling - providing magnetic field values (total field, dip, and declination) at or near the Earth’s surface. A cloud-based real-time model improves the internal field models by modeling the magnetic fields originating in the Earth’s magnetosphere and ionosphere and their induced secondary fields in real-time for low and mid-latitude regions. We evaluate the Weimer magnetic field model (Weimer, 2013), which is an empirical representation of high-latitude magnetic field variations driven by solar wind measurements at Sun-Earth L1, as a potential candidate for modeling the magnetic field variations in the high-latitude regions. We use observatory data from the INTERMAGNET and SuperMAG networks to compare the predicted Weimer magnetic variations to the observed variations on the ground. We find that the Weimer model reduces the high-latitude standard deviations by ~30% when daily baselines are subtracted from the data. We also compare the Weimer performance to the University of Michigan’s Geospace model during selected geomagnetic storms., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)
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- 2023
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11. Prompt Acceleration of Magnetospheric Electrons to Ultrarelativistic Energies by the 17 March 2015 Interplanetary Shock
- Author
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Kanekal, S. G, Baker, D. N, Fennell, J. F, Jones, A, Schiller, Q, Richardson, I.G, Li, X, Turner, D. L, Califf, S, Claudepierre, S. G, and Wilson, L. B. III
- Subjects
Geophysics ,Space Radiation - Abstract
Trapped electrons in Earth's outer Van Allen radiation belt are influenced profoundly by solar phenomena such as high-speed solar wind streams, coronal mass ejections (CME), and interplanetary (IP) shocks. In particular, strong IP shocks compress the magnetosphere suddenly and result in rapid energization of electrons within minutes. It is believed that the electric fields induced by the rapid change in the geomagnetic field are responsible for the energization. During the latter part of March 2015, a CME impact led to the most powerful geomagnetic storm (minimum Dst = −223 nT at 17 March, 23 UT) observed not only during the Van Allen Probe era but also the entire preceding decade. Magnetospheric response in the outer radiation belt eventually resulted in elevated levels of energized electrons. The CME itself was preceded by a strong IP shock whose immediate effects vis-a-vis electron energization were observed by sensors on board the Van Allen Probes. The comprehensive and high-quality data from the Van Allen Probes enable the determination of the location of the electron injection, timescales, and spectral aspects of the energized electrons. The observations clearly show that ultrarelativistic electrons with energies E greater than 6 MeV were injected deep into the magnetosphere at L approximately equals 3 within about 2 min of the shock impact. However, electrons in the energy range of approximately equals 250 keV to approximately equals 900 keV showed no immediate response to the IP shock. Electric and magnetic fields resulting from the shock-driven compression complete the comprehensive set of observations that provide a full description of the near-instantaneous electron energization.
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- 2016
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12. Multi‐Event Study on the Connection Between Subauroral Polarization Streams and Deep Energetic Particle Injections in the Inner Magnetosphere
- Author
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Califf, S., primary, Zhao, H., additional, Gkioulidou, M., additional, Manweiler, J. W., additional, Mitchell, D. G., additional, and Tian, S., additional
- Published
- 2022
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13. International Geomagnetic Reference Field: the thirteenth generation
- Author
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Alken, P, Thébault, E, Beggan, C.D., Amit, H, Aubert, J, Baerenzung, J, Bondar, T N, Brown, W.J., Califf, S, Chambodut, A, Chulliat, A, Cox, G.A., Finlay, C C, Fournier, A, Gillet, N, Grayver, A, Hammer, M D, Holschneider, M, Huder, L, Hulot, G, Jager, T, Kloss, C, Korte, M, Kuang, W, Kuvshinov, A, Langlais, B, Léger, J-M, Lesur, V, Livermore, P W, Lowes, F J, Macmillan, S., Magnes, W, Mandea, M, Marsal, S, Matzka, W, Metman, M, Minami, T, Morschhauser, A, Mound, J E, Nair, M, Nakano, S, Olsen, N, Pavón-Carrasco, F J, Petrov, V G, Ropp, G, Rother, M, Sabaka, T J, Sanchez, S, Saturnino, D, Schnepf, N R, Shen, X, Stolle, C, Tangborn, A, Tøffner-Clausen, L, Toh, H, Torta, J M, Varner, J, Vervelidou, F, Vigneron, P, Wardinski, I, Wicht, J, Woods, A, Yang, Y, Zeren, Z, Zhou, B, Alken, P, Thébault, E, Beggan, C.D., Amit, H, Aubert, J, Baerenzung, J, Bondar, T N, Brown, W.J., Califf, S, Chambodut, A, Chulliat, A, Cox, G.A., Finlay, C C, Fournier, A, Gillet, N, Grayver, A, Hammer, M D, Holschneider, M, Huder, L, Hulot, G, Jager, T, Kloss, C, Korte, M, Kuang, W, Kuvshinov, A, Langlais, B, Léger, J-M, Lesur, V, Livermore, P W, Lowes, F J, Macmillan, S., Magnes, W, Mandea, M, Marsal, S, Matzka, W, Metman, M, Minami, T, Morschhauser, A, Mound, J E, Nair, M, Nakano, S, Olsen, N, Pavón-Carrasco, F J, Petrov, V G, Ropp, G, Rother, M, Sabaka, T J, Sanchez, S, Saturnino, D, Schnepf, N R, Shen, X, Stolle, C, Tangborn, A, Tøffner-Clausen, L, Toh, H, Torta, J M, Varner, J, Vervelidou, F, Vigneron, P, Wardinski, I, Wicht, J, Woods, A, Yang, Y, Zeren, Z, and Zhou, B
- Abstract
In December 2019, the International Association of Geomagnetism and Aeronomy (IAGA) Division V Working Group (V-MOD) adopted the thirteenth generation of the International Geomagnetic Reference Field (IGRF). This IGRF updates the previous generation with a definitive main field model for epoch 2015.0, a main field model for epoch 2020.0, and a predictive linear secular variation for 2020.0 to 2025.0. This letter provides the equations defining the IGRF, the spherical harmonic coefficients for this thirteenth generation model, maps of magnetic declination, inclination and total field intensity for the epoch 2020.0, and maps of their predicted rate of change for the 2020.0 to 2025.0 time period.
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- 2021
14. Evaluation of candidate models for the 13th generation International Geomagnetic Reference Field
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Alken, Patrick, primary, Thebault, Erwan, additional, Beggan, Ciaran, additional, Aubert, Julien, additional, Baerenzung, Julien, additional, Brown, William J., additional, Califf, S., additional, Chulliat, Arnaud, additional, Cox, G.A., additional, Finlay, Christopher C., additional, Fournier, Alexandre, additional, Gillet, Nicolas, additional, Hammer, Magnus D., additional, Holschneider, Matthias, additional, Hulot, Gauthier, additional, Korte, Monika, additional, Lesur, Vincent, additional, Livermore, Philippe W., additional, Lowes, Frank J., additional, Macmillan, Susan, additional, Nair, Manoj, additional, Olsen, Nils, additional, Ropp, G., additional, Rother, Martin, additional, Schnepf, Neesha, additional, Stolle, Claudia, additional, Toh, Hiroaki, additional, Vervelidou, Fotini, additional, Vigneron, Pierre, additional, and Wardinski, Ingo, additional
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- 2020
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15. Generalized Substorm Current Wedge Model: Two Types of Dipolarizations in the Inner Magnetosphere
- Author
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Ohtani, S., primary, Motoba, T., additional, Takahashi, K., additional, and Califf, S., additional
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- 2020
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16. Effect of Sitagliptin on Cardiovascular Outcomes in Type 2 Diabetes
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Green JB, Bethel MA, Armstrong PW, Buse JB, Engel SS, Garg J, Josse R, Kaufman KD, Koglin J, Korn S, Lachin JM, McGuire DK, Pencina MJ, Standl E, Stein PP, Suryawanshi S, Van de Werf F, Peterson ED, Holman RR, Josse RG, Califf RM, Goldstein BJ, Shapiro DR, Silverman R, Bethel A, Green J, Hayden S, Hannan K, Quintero K, Rorick T, Berdan L, Leloudis D, Califf S, Wilson M, McFarron D, Trollinger K, Pesarchick J, Eskenazi L, Campbell C, Townes O, Tolsma D, Keenan J, Milton J, Athwal R, Darbyshire J, Doran Z, Kennedy I, Gregory V, Lokhnygina Y, Prather K, Wolfley A, Usman M, Tajjar A, Gray R, Pfeffer MA, Gerstein HC, Groop L, McMurray JJ, Pocock SJ, Clayton T, Sinay I, Brieger D, Stranks S, Scheen A, Lopes R, Tankova T, Hramiak I, Grado CR, Wenying Y, Ge J, Aschner P, Skrha J, Ambos A, Strandberg T, Travert F, Hanefeld M, Riefflin A, Chan JC, Ofner P, Reddy NK, Christopher J, Mathur A, Arambam P, Mittal S, Manchanda M, Wainstein J, Ambrosio G, Pirags V, Jakuboniene N, Mohamed M, Scott R, White H, Cornel J, Halvorsen S, Tykarski A, Veresiu IA, Dreval AV, Misinkova I, Tai E, Krahulec B, Distiller L, Park Y, Rovira A, Alversson M, Chuang LM, Delibasi T, Adler A, Rodbard HW, Marre M, Goff D, Chacra A, DeVore A, Beaven A, Shah B, Hirsch B, Batch B, Bushnell C, Patel C, Melloni C, Henshaw C, Kong D, Bernecki G, Tillman H, Kang HJ, Hawes J, Strickler J, Piccini J, Wilder J, Alexander K, Mahaffey K, Patel K, Hyland K, Newby K, Jackson L, Cooper L, Armaganijan L, Szczeh L, Koshizaka M, Roe M, Morse M, Guimaraes P, Hess P, Tricoci P, Mehta R, Mathews R, Kociol R, Harrison R, Mentz R, Pokorney S, Leblanc T, Lazzarini V, Eapen Z, Truffa A, Fosbol E, Brito F, Katz M, Bahit M, Santos M, Barros P, Bernardez S, Alvarisqueta AF, Arias P, Cagide AL, Calella PR, Cantero MC, Canella JP, Cipullo MA, de Loredo L, Gelersztein ES, Gorban de Lapertosa SB, Klyver MI, Maffei LE, Maldonado N, Oviedo AI, Piskorz DL, Ridruejo MC, Saavedra SS, Sessa HA, Sinay IR, Sposetti GD, Ulla MR, Vico ML, Waitman JN, Binnekamp M, Carroll P, Cheung W, Colman P, Davis T, De Looze F, dEmden M, Fulcher G, Gerstman M, Hamilton A, Lehman S, Moses R, Proietto J, Roberts A, Shaw J, Simpson R, Sinha A, Tan Y, Topliss D, Vora P, Waites J, Crenier L, Descamps O, Keymeulen B, Mathieu C, Nobels F, Van den Bruel A, Van Gaal L, Borges JL, Costa e Forti A, Eliaschewitz FG, Felício JS, Griz LH, Hissa MN, Leite S, Panarotto D, Pimentel Filho P, Rassi N, Saraiva JK, Sgarbi JA, Silva RP, Tambascia M, Weber Silva DM, Bobeva R, Bostandzhieva R, Cinlikov I, Georgieva M, Iliev D, Ilieva E, Kovacheva S, Liubenova L, Nikitov Z, SHeinikova G, Slavcheva A, Spasova V, Temelkova-Kurktschiev T, Velichka D, Yakov A, Carpentier A, Chiasson JL, Constance C, Dumas R, Filteau P, Garceau C, Huynh T, Kaiser S, Kornder J, Leiter L, Mereu L, Miller D, Pandey S, Punthakee Z, Rabasa-Lhoret R, Robitaille Y, Saunders K, Sigal R, Sigalas J, Vizel S, Weisnagel S, Woo V, Yale JF, Yared K, Zinman B, Bunster Balocchi LB, Escobar Cerda EE, Garces Flores EE, Lanas Zanetti FT, Larrazabal Miranda Adel P, Morales Alvarado JM, Olivares Cañon CM, Potthoff Cárdenas SH, Raffo Grado CA, Rodriguez Venegas ME, Saavedra Gajardo VA, Westerberg Maldonado BH, Chen LL, Dong J, Guo X, Li QM, Shi B, Tang XL, Yang T, Yang WY, Zheng SX, Aschner Montoya P, Botero Lopez R, Coronel Arroyo JA, Cure CA, Gómez Medina AM, Molina DI, Perez Amador GA, Reyes Rincon A, Urina Triana MA, Valenzuela Rincon A, Vélez Pelaez S, Yupanqui Lozno H, Brabec T, Brychta T, Hasalova Zapletalova J, Havelkova J, Hejnicova K, Hola O, Hornackova M, Hrdina T, Kafkova D, Kellnerova I, Krystl T, Kutejova V, Mikulkova I, Nevrla J, Pantlikova C, Petr M, Racicka E, Sarbochova R, Smolenakova K, Turcinek R, Urbancova K, Vejvodova J, Vondrakova M, Zachoval R, Alt I, Kaasik Ü, Kiiroja K, Lanno R, Märtsin K, Past M, Vides H, Viitas L, Kantola I, Nieminen S, Perhonen M, Strand J, Valle T, Clergeot A, Couffinhal T, Courreges JP, Gouet D, Moulin P, Ziegler O, Badenhoop K, Behnke T, Bender G, Braun M, Dshabrailov J, Hamann A, Himpel-Boenninghoff A, Kamke W, Kasperk C, Luedemann J, Mayr P, Merkel M, Oerter EM, Ohlow MA, Ott P, Overhoff U, Paschen B, Remppis R, Rose L, Schumm-Draeger PM, Segiet T, Strotmann HJ, Stuchlik G, Stürmer W, Thinesse-Mallwitz M, Tytko A, Wendisch U, Wurziger J, Ho AY, Kam G, Kong AP, Lam YY, Lau EY, Lee S, Siu SC, Tomlinson B, Tsang CC, Yeung VT, Dezső E, Dudás M, Földesi I, Fülöp T, Késmárki N, Koranyi L, Nagy K, Oroszlán T, Pécsvárady Z, Ples Z, Taller A, Agarwal P, Ambulkar S, Aravind S, Balaji V, Kalra S, Kesavadev J, Kudalkar H, Kumar A, Misra A, Mithal A, Mohan V, Pitale S, Ramu M, Reddy N, Shah S, Shamanna P, Sharda A, Sharma A, Shunmugavelu M, Srikanta S, Suryaprakash G, Abramov G, Adawi F, Bashkin A, Darawsha M, Fuchs S, Harman-Boehm I, Hayek T, Jaffe A, Knobler H, Minuchin O, Mosseri M, Shechter M, Shimon I, Stern N, Tsur A, Vishlitzky V, Alfonsi F, Cavalot F, Del Vecchio L, Frisinghelli A, Gambardella S, Lauro D, Lembo G, Leotta S, Mondillo S, Novo S, Pedrinelli R, Piatti P, Salvioni A, Tritto I, Zavaroni DZ, Ahn KJ, Choi KM, Chung C, Han SJ, Kim DM, Kim IJ, Kim MH, Lee IK, Nam M, Park IeB, Park KS, Park TS, Rhee EJ, Yoo SJ, Andersone I, Balode A, Eglite R, Gersamija A, Kakurina N, Jegere B, Leitane I, Pastare S, Stalte V, Teterovska D, Baltramonaitiene K, Barsiene L, Ceponis J, Lasiene J, Levinger A, Sirutaviciene A, Sulskiene M, Urbanaviciene L, Valius L, Varanauskiene E, Velickiene D, Mahendran KA, Abu Hassan MR, Aziz NA, Hussein Z, Ismail IS, Kamaruddin NA, Nordin Z, Nayar SK, Ramanathan GR, Sothiratnam R, Beijerbacht H, Breedveld R, Cornel JH, Den Hartog F, Hermans W, Kietselaer B, Kooy A, Lenderink T, Nierop P, Remmen J, Rojas Lingan G, Ronner E, Van der Heijden R, Van Hessen M, van Kempen W, Voors-Pette C, Westendorp I, Baker J, Benatar J, Cutfield R, Krebs J, Leikis R, Lunt H, Manning P, Williams M, Birkeland K, Claudi T, Istad H, Karlsson T, Ossum Gronert J, Arciszewska M, Artemiuk E, Blach E, Blicharski T, Cypryk K, Dabrowska M, Górny G, Górska M, Jakubowska I, Jazwinska-Tarnawska E, Karczmarczyk A, Kitowska-Koterla J, Koltowski L, Krzyzagorska E, Pasternak D, Pentela-Nowicka J, Piesiewicz W, Przekwas-Jaruchowska M, Rajzer M, Salamon-Ferenc A, Sawicki A, Skowron T, Śmiałowski A, Albota A, Alexandru C, Crisan C, Dumitrescu A, Ferariu IE, Lupusoru DA, Munteanu M, Negru D, Nicolau A, Pintiliei E, Popescu A, Serban G, Voitec M, Babenko A, Barbarash O, Bondar I, Chizhov P, Demin A, Dora S, Dreval A, Ershova O, Gratsiansky N, Ketova G, Kotelnikov M, Levashov S, Morugova T, Mustafina S, Pekarskiy S, Raskina T, Rechkova E, Samoylova Y, Sazonova O, Sherenkov A, Shilkina N, Stetsyuk O, Tretyakova T, Turova E, Valeeva F, Zadionchenko V, Dalan R, Tan RS, Tay L, Buganova I, Fabry J, Jan C, Toserova E, Zak R, Zimanova J, Badat A, Bester F, Burgess L, De Jong D, Ellis G, Fouche L, Govender P, Govind U, Naidoo V, Nieuwoudt G, Nortje H, Rheeder P, Robertson L, Siddique N, Stapelberg AM, Trinder Y, Van Der Merwe A, Van Zyl L, Viljoen M, Wilhase A, Botella M, Civeira Murillo F, de Teresa L, Del Cañizo FJ, Extremera BG, Gimeno EJ, Martin-Hidalgo A, Morales C, Nubiola A, Tinahones Madueño F, Tranche S, Trescolí Serrano C, Alvarsson M, Eizyk E, Gillblad A, Johansson P, Löndahl M, Ohlsson-Önerud Å, Rautio A, Sundström U, Torstensson I, Chen JF, Chou CW, Ho LT, Hsieh IC, Huang BH, Huang CL, Huang CN, Lai WT, Lo PH, Pei D, Sheu WH, Wang SY, Araz M, Bakiner O, Comlekci A, Guler S, Sahin I, Sarac F, Tarkun I, Ukinc K, Yilmaz M, Abdulhakim E, Abraham P, Adamson K, Blagden M, Bundy C, Daly M, Davies M, Deshpande M, Gillings S, Harvey P, Horvathova V, Hristova D, Jaap A, Johnson A, Jones H, Kerrane J, Kilvert A, Ko T, Kumar J, Lindsay R, Litchfield J, McCrimmon R, McKnight J, Millward B, Oyesile B, Purewal T, Ravikumar C, Robinson A, Sathyapalan T, Simpson H, Thomas H, Turner W, Weaver J, Wilding J, Wiles P, Adkins K, Akpunonu B, Albu J, Anagnostis G, Anastasi L, Argoud G, Aroda V, Azizad M, Banerji MA, Bartkowiak A Jr, Bays H, Behn P, Bergenstal R, Bhargava A, Bias D, Bolster E, Buchanan P, Busch R, Chadha C, Chang M, Cheng C, Cohen A, Cohen J, Cole B, Connery L, Cooperman M, Cushman W, DAgostino R, Dayamani P, De Lemos J, De Meireles M, Dean J, DeHart D, Detweiler R, Donovan D, Dugano-Daphnis P, Dulin M, Dunn F, Eaton C, Erickson B, Estevez R, Feinglos M, Fonseca V, Force R, Forker A, Fox D, Gabriel J, Garcia R, Garvey T, Gaudiani L, Getaneh A, Goldberg A, Goldman S, Hairston K, Harris R, Haught W, Hidalgo H Jr, Higgins A, Houchin V, Ison R, Jacobs G, Jaffrani N, Jafry B, Kapsner P, Kaye W, Labroo A, Levinson L, Lewis S, Lillestol M, Luttrell L, Madu I, McNeill R, Merrick B, Metzger F, Nadar V, Nagelberg S, Nash S, Oparil S, Osei K, Papademetriou V, Patel N, Pedley C, Prentiss A, Radbill M, Raisinghani A, Rassouli N, Reddy R, Rees P, Rendell M, Robbins D, Rodbard H, Rohlf J, Roseman H, Rudolph L, Sadler L, Schnall A, Schramm R, Schubart U, Seneviratne T, Shanik M, Snyder H, Sorli C, Stich M, Sweeney ME, Tsao J, Ukwade P, Viswanath D, Vo A, Vogel C, Voyce S, Weintraub H, White J, Wood M, Wu P, Wysham C, Zimmerman R, Pathology/molecular and cellular medicine, Diabetes Pathology & Therapy, and Green JB, Bethel MA, Armstrong PW, Buse JB, Engel SS, Garg J, Josse R, Kaufman KD, Koglin J, Korn S, Lachin JM, McGuire DK, Pencina MJ, Standl E, Stein PP, Suryawanshi S, Van de Werf F, Peterson ED, Holman RR, Holman RR, Peterson ED, Holman RR, Peterson ED, Armstrong PW, Buse JB, Josse RG, Kaufman KD, Koglin J, Korn S, Lachin JM, McGuire DK, Standl E, Stein PP, Suryawanshi S, Van de Werf F, Engel SS, Califf RM, Goldstein BJ, Shapiro DR, Silverman R, Bethel A, Green J, Hayden S, Hannan K, Quintero K, Rorick T, Berdan L, Leloudis D, Califf S, Wilson M, McFarron D, Trollinger K, Pesarchick J, Eskenazi L, Campbell C, Townes O, Tolsma D, Keenan J, Milton J, Athwal R, Darbyshire J, Doran Z, Kennedy I, Gregory V, Garg J, Lokhnygina Y, Prather K, Wolfley A, Usman M, Tajjar A, Gray R, Pfeffer MA, Gerstein HC, Groop L, McMurray JJ, Pocock SJ, Clayton T, Sinay I, Brieger D, Stranks S, Scheen A, Lopes R, Tankova T, Hramiak I, Grado CR, Wenying Y, Ge J, Aschner P, Skrha J, Ambos A, Strandberg T, Travert F, Hanefeld M, Riefflin A, Chan JC, Ofner P, Reddy NK, Christopher J, Mathur A, Arambam P, Mittal S, Manchanda M, Wainstein J, Ambrosio G, Pirags V, Jakuboniene N, Mohamed M, Scott R, White H, Cornel J, Halvorsen S, Tykarski A, Veresiu IA, Dreval AV, Misinkova I, Tai E, Krahulec B, Distiller L, Park Y, Rovira A, Alversson M, Chuang LM, Delibasi T, Adler A, Rodbard HW, Marre M, Goff D, Chacra A, DeVore A, Beaven A, Shah B, Hirsch B, Batch B, Bushnell C, Patel C, Melloni C, Henshaw C, Kong D, McFarron D, Bernecki G, Tillman H, Kang HJ, Green J, Hawes J, Strickler J, Piccini J, Wilder J, Alexander K, Mahaffey K, Patel K, Hyland K, Newby K, Jackson L, Cooper L, Armaganijan L, Szczeh L, Koshizaka M, Roe M, Morse M, Guimaraes P, Hess P, Tricoci P, Mehta R, Lopes R, Mathews R, Kociol R, Harrison R, Mentz R, Pokorney S, Leblanc T, Lazzarini V, Eapen Z, Truffa A, Fosbol E, Brito F, Katz M, Bahit M, Santos M, Barros P, Bernardez S, Alvarisqueta AF, Arias P, Cagide AL, Calella PR, Cantero MC, Canella JP, Cipullo MA, de Loredo L, Gelersztein ES, Gorban de Lapertosa SB, Klyver MI, Maffei LE, Maldonado N, Oviedo AI, Piskorz DL, Ridruejo MC, Saavedra SS, Sessa HA, Sinay IR, Sposetti GD, Ulla MR, Vico ML, Waitman JN, Binnekamp M, Carroll P, Cheung W, Colman P, Davis T, De Looze F, dEmden M, Fulcher G, Gerstman M, Hamilton A, Lehman S, Moses R, Proietto J, Roberts A, Shaw J, Simpson R, Sinha A, Stranks S, Tan Y, Topliss D, Vora P, Waites J, Crenier L, Descamps O, Keymeulen B, Mathieu C, Nobels F, Scheen A, Van den Bruel A, Van Gaal L, Borges JL, Costa e Forti A, Eliaschewitz FG, Felício JS, Griz LH, Hissa MN, Leite S, Panarotto D, Pimentel Filho P, Rassi N, Saraiva JK, Sgarbi JA, Silva RP, Tambascia M, Weber Silva DM, Bobeva R, Bostandzhieva R, Cinlikov I, Georgieva M, Iliev D, Ilieva E, Kovacheva S, Liubenova L, Nikitov Z, SHeinikova G, Slavcheva A, Spasova V, Tankova T, Temelkova-Kurktschiev T, Velichka D, Yakov A, Carpentier A, Chiasson JL, Constance C, Dumas R, Filteau P, Garceau C, Hramiak I, Huynh T, Kaiser S, Kornder J, Leiter L, Mereu L, Miller D, Pandey S, Punthakee Z, Rabasa-Lhoret R, Robitaille Y, Saunders K, Sigal R, Sigalas J, Vizel S, Weisnagel S, Woo V, Yale JF, Yared K, Zinman B, Bunster Balocchi LB, Escobar Cerda EE, Garces Flores EE, Lanas Zanetti FT, Larrazabal Miranda Adel P, Morales Alvarado JM, Olivares Cañon CM, Potthoff Cárdenas SH, Raffo Grado CA, Rodriguez Venegas ME, Saavedra Gajardo VA, Westerberg Maldonado BH, Chen LL, Dong J, Guo X, Li QM, Shi B, Tang XL, Yang T, Yang WY, Zheng SX, Aschner Montoya P, Botero Lopez R, Coronel Arroyo JA, Cure CA, Gómez Medina AM, Molina DI, Perez Amador GA, Reyes Rincon A, Urina Triana MA, Valenzuela Rincon A, Vélez Pelaez S, Yupanqui Lozno H, Brabec T, Brychta T, Hasalova Zapletalova J, Havelkova J, Hejnicova K, Hola O, Hornackova M, Hrdina T, Kafkova D, Kellnerova I, Krystl T, Kutejova V, Mikulkova I, Nevrla J, Pantlikova C, Petr M, Racicka E, Sarbochova R, Skrha J, Smolenakova K, Turcinek R, Urbancova K, Vejvodova J, Vondrakova M, Zachoval R, Alt I, Ambos A, Kaasik Ü, Kiiroja K, Lanno R, Märtsin K, Past M, Vides H, Viitas L, Kantola I, Nieminen S, Perhonen M, Strand J, Strandberg T, Valle T, Clergeot A, Couffinhal T, Courreges JP, Gouet D, Moulin P, Travert F, Ziegler O, Badenhoop K, Behnke T, Bender G, Braun M, Dshabrailov J, Hamann A, Hanefeld M, Himpel-Boenninghoff A, Kamke W, Kasperk C, Luedemann J, Mayr P, Merkel M, Oerter EM, Ohlow MA, Ott P, Overhoff U, Paschen B, Remppis R, Riefflin A, Rose L, Schumm-Draeger PM, Segiet T, Strotmann HJ, Stuchlik G, Stürmer W, Thinesse-Mallwitz M, Tytko A, Wendisch U, Wurziger J, Ho AY, Kam G, Kong AP, Lam YY, Lau EY, Lee S, Siu SC, Tomlinson B, Tsang CC, Yeung VT, Dezső E, Dudás M, Földesi I, Fülöp T, Késmárki N, Koranyi L, Nagy K, Ofner P, Oroszlán T, Pécsvárady Z, Ples Z, Taller A, Agarwal P, Ambulkar S, Aravind S, Balaji V, Christopher J, Kalra S, Kesavadev J, Kudalkar H, Kumar A, Misra A, Mithal A, Mohan V, Pitale S, Ramu M, Reddy N, Shah S, Shamanna P, Sharda A, Sharma A, Shunmugavelu M, Srikanta S, Suryaprakash G, Abramov G, Adawi F, Bashkin A, Darawsha M, Fuchs S, Harman-Boehm I, Hayek T, Jaffe A, Knobler H, Minuchin O, Mosseri M, Shechter M, Shimon I, Stern N, Tsur A, Vishlitzky V, Wainstein J, Alfonsi F, Cavalot F, Del Vecchio L, Frisinghelli A, Gambardella S, Lauro D, Lembo G, Leotta S, Mondillo S, Novo S, Pedrinelli R, Piatti P, Salvioni A, Tritto I, Zavaroni DZ, Ahn KJ, Choi KM, Chung C, Han SJ, Kim DM, Kim IJ, Kim MH, Lee IK, Nam M, Park IeB, Park KS, Park TS, Park Y, Rhee EJ, Yoo SJ, Andersone I, Balode A, Eglite R, Gersamija A, Kakurina N, Jegere B, Leitane I, Pastare S, Pirags V, Stalte V, Teterovska D, Baltramonaitiene K, Barsiene L, Ceponis J, Jakuboniene N, Lasiene J, Levinger A, Sirutaviciene A, Sulskiene M, Urbanaviciene L, Valius L, Varanauskiene E, Velickiene D, Mahendran KA, Abu Hassan MR, Aziz NA, Hussein Z, Ismail IS, Kamaruddin NA, Mohamed M, Nordin Z, Nayar SK, Ramanathan GR, Sothiratnam R, Beijerbacht H, Breedveld R, Cornel JH, Den Hartog F, Hermans W, Kietselaer B, Kooy A, Lenderink T, Nierop P, Remmen J, Rojas Lingan G, Ronner E, Van der Heijden R, Van Hessen M, van Kempen W, Voors-Pette C, Westendorp I, Baker J, Benatar J, Cutfield R, Krebs J, Leikis R, Lunt H, Manning P, Scott R, Williams M, Birkeland K, Claudi T, Halvorsen S, Istad H, Karlsson T, Ossum Gronert J, Arciszewska M, Artemiuk E, Blach E, Blicharski T, Cypryk K, Dabrowska M, Górny G, Górska M, Jakubowska I, Jazwinska-Tarnawska E, Karczmarczyk A, Kitowska-Koterla J, Koltowski L, Krzyzagorska E, Pasternak D, Pentela-Nowicka J, Piesiewicz W, Przekwas-Jaruchowska M, Rajzer M, Salamon-Ferenc A, Sawicki A, Skowron T, Śmiałowski A, Tykarski A, Albota A, Alexandru C, Crisan C, Dumitrescu A, Ferariu IE, Lupusoru DA, Munteanu M, Negru D, Nicolau A, Pintiliei E, Popescu A, Serban G, Veresiu IA, Voitec M, Babenko A, Barbarash O, Bondar I, Chizhov P, Demin A, Dora S, Dreval A, Ershova O, Gratsiansky N, Ketova G, Kotelnikov M, Levashov S, Morugova T, Mustafina S, Pekarskiy S, Raskina T, Rechkova E, Samoylova Y, Sazonova O, Sherenkov A, Shilkina N, Stetsyuk O, Tretyakova T, Turova E, Valeeva F, Zadionchenko V, Dalan R, Tan RS, Tay L, Buganova I, Fabry J, Jan C, Krahulec B, Toserova E, Zak R, Zimanova J, Badat A, Bester F, Burgess L, De Jong D, Distiller L, Ellis G, Fouche L, Govender P, Govind U, Naidoo V, Nieuwoudt G, Nortje H, Rheeder P, Robertson L, Siddique N, Stapelberg AM, Trinder Y, Van Der Merwe A, Van Zyl L, Viljoen M, Wilhase A, Botella M, Civeira Murillo F, de Teresa L, Del Cañizo FJ, Extremera BG, Gimeno EJ, Martin-Hidalgo A, Morales C, Nubiola A, Rovira A, Tinahones Madueño F, Tranche S, Trescolí Serrano C, Alvarsson M, Eizyk E, Gillblad A, Johansson P, Löndahl M, Ohlsson-Önerud Å, Rautio A, Sundström U, Torstensson I, Chen JF, Chou CW, Chuang LM, Ho LT, Hsieh IC, Huang BH, Huang CL, Huang CN, Lai WT, Lo PH, Pei D, Sheu WH, Wang SY, Araz M, Bakiner O, Comlekci A, Delibasi T, Guler S, Sahin I, Sarac F, Tarkun I, Ukinc K, Yilmaz M, Abdulhakim E, Abraham P, Adamson K, Adler A, Blagden M, Bundy C, Daly M, Davies M, Deshpande M, Gillings S, Harvey P, Horvathova V, Horvathova V, Hristova D, Jaap A, Johnson A, Jones H, Kerrane J, Kilvert A, Ko T, Kumar J, Lindsay R, Litchfield J, McCrimmon R, McKnight J, Millward B, Oyesile B, Purewal T, Ravikumar C, Robinson A, Sathyapalan T, Simpson H, Thomas H, Turner W, Weaver J, Wilding J, Wiles P, Adkins K, Akpunonu B, Albu J, Anagnostis G, Anastasi L, Argoud G, Aroda V, Azizad M, Banerji MA, Bartkowiak A Jr, Bays H, Behn P, Bergenstal R, Bhargava A, Bias D, Bolster E, Buchanan P, Busch R, Chadha C, Chang M, Cheng C, Cohen A, Cohen J, Cole B, Connery L, Cooperman M, Cushman W, DAgostino R, Davies M, Dayamani P, De Lemos J, De Meireles M, Dean J, DeHart D, Detweiler R, Donovan D, Dugano-Daphnis P, Dulin M, Dunn F, Eaton C, Erickson B, Estevez R, Feinglos M, Fonseca V, Force R, Forker A, Fox D, Gabriel J, Garcia R, Garvey T, Gaudiani L, Getaneh A, Goff D, Goldberg A, Goldman S, Hairston K, Harris R, Haught W, Hidalgo H Jr, Higgins A, Houchin V, Ison R, Jacobs G, Jaffrani N, Jafry B, Kapsner P, Kaye W, Labroo A, Levinson L, Lewis S, Lillestol M, Luttrell L, Madu I, McNeill R, Merrick B, Metzger F, Nadar V, Nagelberg S, Nash S, Oparil S, Osei K, Papademetriou V, Patel N, Pedley C, Prentiss A, Radbill M, Raisinghani A, Rassouli N, Reddy R, Rees P, Rendell M, Robbins D, Rodbard H, Rohlf J, Roseman H, Rudolph L, Sadler L, Schnall A, Schramm R, Schubart U, Seneviratne T, Shanik M, Snyder H, Sorli C, Stich M, Sweeney ME, Tsao J, Ukwade P, Viswanath D, Vo A, Vogel C, Voyce S, Weintraub H, White J, Wood M, Wu P, Wysham C, Zimmerman R
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Oral ,medicine.medical_specialty ,Heart diseases ,Glycosylated ,Administration, Oral ,heart failure ,Type 2 diabetes ,Dipeptidyl peptidase-4 inhibitor ,Kaplan-Meier Estimate ,Placebo ,Sitagliptin Phosphate ,Sitagliptin, Cardiovascular Outcomes ,chemistry.chemical_compound ,Drug Therapy ,Double-Blind Method ,Internal medicine ,Diabetes Mellitus ,medicine ,Humans ,Hypoglycemic Agents ,Glycated Hemoglobin ,Hemoglobin A, Glycosylated ,Cardiovascular Diseases ,Diabetes Mellitus, Type 2 ,Drug Therapy, Combination ,Follow-Up Studies ,Heart Diseases ,Heart Failure ,Hospitalization ,Pyrazines ,Triazoles ,Medicine (all) ,business.industry ,Semaglutide ,Hemoglobin A ,General Medicine ,ta3121 ,medicine.disease ,Surgery ,Cardiovascular diseases ,chemistry ,Sitagliptin ,Administration ,Combination ,Glycated hemoglobin ,business ,Type 2 ,Alogliptin ,medicine.drug - Abstract
BACKGROUND: Data are lacking on the long-term effect on cardiovascular events of adding sitagliptin, a dipeptidyl peptidase 4 inhibitor, to usual care in patients with type 2 diabetes and cardiovascular disease. METHODS: In this randomized, double-blind study, we assigned 14,671 patients to add either sitagliptin or placebo to their existing therapy. Open-label use of antihyperglycemic therapy was encouraged as required, aimed at reaching individually appropriate glycemic targets in all patients. To determine whether sitagliptin was noninferior to placebo, we used a relative risk of 1.3 as the marginal upper boundary. The primary cardiovascular outcome was a composite of cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for unstable angina. RESULTS: During a median follow-up of 3.0 years, there was a small difference in glycated hemoglobin levels (least-squares mean difference for sitagliptin vs. placebo, -0.29 percentage points; 95% confidence interval [CI], -0.32 to-0.27). Overall, the primary outcome occurred in 839 patients in the sitagliptin group (11.4%; 4.06 per 100 person-years) and 851 patients in the placebo group (11.6%; 4.17 per 100 person-years). Sitagliptin was noninferior to placebo for the primary composite cardiovascular outcome (hazard ratio, 0.98; 95% CI, 0.88 to 1.09; P
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- 2015
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17. Arcjet Thruster Influence on Local Magnetic Field Measurements from a Geostationary Satellite
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Califf, S., primary, Loto’aniu, T. M., additional, Early, D., additional, and Grotenhuis, M., additional
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- 2020
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18. Correcting the Arcjet Thruster Disturbance in GOES‐16 Magnetometer Data
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Califf, S., primary, Early, D., additional, Grotenhuis, M., additional, Loto'aniu, T. M., additional, and Kronenwetter, J., additional
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- 2020
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19. Van Allen Probes Measurements of Energetic Particle Deep Penetration Into the Low L Region (L < 4) During the Storm on 8 April 2016
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Zhao, H., primary, Baker, D. N., additional, Califf, S., additional, Li, X., additional, Jaynes, A. N., additional, Leonard, T., additional, Kanekal, S. G., additional, Blake, J. B., additional, Fennell, J. F., additional, Claudepierre, S. G., additional, Turner, D. L., additional, Reeves, G. D., additional, and Spence, H. E., additional
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- 2017
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20. The role of the convection electric field in filling the slot region between the inner and outer radiation belts
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Califf, S., primary, Li, X., additional, Zhao, H., additional, Kellerman, A., additional, Sarris, T. E., additional, Jaynes, A., additional, and Malaspina, D. M., additional
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- 2017
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21. Empirical estimates and theoretical predictions of the shorting factor for the THEMIS double-probe electric field instrument
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Califf, S., primary and Cully, C. M., additional
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- 2016
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22. Large‐amplitude electric fields in the inner magnetosphere: Van Allen Probes observations of subauroral polarization streams
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Califf, S., primary, Li, X., additional, Wolf, R. A., additional, Zhao, H., additional, Jaynes, A. N., additional, Wilder, F. D., additional, Malaspina, D. M., additional, and Redmon, R., additional
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- 2016
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23. Van Allen Probes Measurements of Energetic Particle Deep Penetration Into the Low L Region (<italic>L</italic> < 4) During the Storm on 8 April 2016.
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Zhao, H., Baker, D. N., Califf, S., Li, X., Jaynes, A. N., Leonard, T., Kanekal, S. G., Blake, J. B., Fennell, J. F., Claudepierre, S. G., Turner, D. L., Reeves, G. D., and Spence, H. E.
- Abstract
Abstract: Using measurements from the Van Allen Probes, a penetration event of tens to hundreds of keV electrons and tens of keV protons into the low L shells (L < 4) is studied. Timing and magnetic local time (MLT) differences of energetic particle deep penetration are unveiled and underlying physical processes are examined. During this event, both proton and electron penetrations are MLT asymmetric. The observed MLT difference of proton penetration is consistent with convection of plasma sheet protons, suggesting enhanced convection during geomagnetic active times to be the cause of energetic proton deep penetration during this event. The observed MLT difference of tens to hundreds of keV electron penetration is completely different from tens of keV protons and cannot be well explained by inward radial diffusion, convection of plasma sheet electrons, or transport of trapped electrons by enhanced convection electric field represented by the Volland‐Stern model or a uniform dawn‐dusk electric field model based on the electric field measurements. It suggests that the underlying physical mechanism responsible for energetic electron deep penetration, which is very important for fully understanding energetic electron dynamics in the low L shells, should be MLT localized. [ABSTRACT FROM AUTHOR]
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- 2017
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24. THEMIS measurements of quasi‐static electric fields in the inner magnetosphere
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Califf, S., primary, Li, X., additional, Blum, L., additional, Jaynes, A., additional, Schiller, Q., additional, Zhao, H., additional, Malaspina, D., additional, Hartinger, M., additional, Wolf, R. A., additional, Rowland, D. E., additional, Wygant, J. R., additional, and Bonnell, J. W., additional
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- 2014
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25. First results from CSSWE CubeSat: Characteristics of relativistic electrons in the near‐Earth environment during the October 2012 magnetic storms
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Li, X., primary, Schiller, Q., additional, Blum, L., additional, Califf, S., additional, Zhao, H., additional, Tu, W., additional, Turner, D. L., additional, Gerhardt, D., additional, Palo, S., additional, Kanekal, S., additional, Baker, D. N., additional, Fennell, J., additional, Blake, J. B., additional, Looper, M., additional, Reeves, G. D., additional, and Spence, H., additional
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- 2013
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26. Statistical Analysis of the Differential Deep Penetration of Energetic Electrons and Protons into the Low LRegion (L< 4)
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Zhao, H., Califf, S. T., Goyal, R., Li, X., Gkioulidou, M., Manweiler, J. W., and Krantz, S.
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Deep penetration of energetic electrons (10s–100s of keV) to low L‐shells (L< 4), as an important source of inner belt electrons, is commonly observed during geomagnetically active times. However, such deep penetration is not observed as frequently for similar energy protons, for which underlying mechanisms are not fully understood. To study their differential deep penetration, we conducted a statistical analysis using phase space densities (PSDs) of µ= 10–50 MeV/G, K= 0.14 G1/2Re electrons and protons from multiyear Van Allen Probes observations. The results suggest systematic differences in electron and proton deep penetration: electron PSD enhancements at low L‐shells occur more frequently, deeply, and faster than protons. For µ= 10–50 MeV/G electrons, the occurrence rate of deep penetration events (defined as daily‐averaged PSD enhanced by at least a factor of 2 within a day at L< 4) is ∼2–3 events/month. For protons, only ∼1 event/month was observed for µ= 10 MeV/G, and much fewer events were identified for µ> 20 MeV/G. Leveraging dual‐Probe configurations, fast electron deep penetrations at L< 4 are revealed: ∼70% of electron deep penetration events occurred within ∼9 hr; ∼8%–13% occurred even within 3 hr, with lower‐µelectrons penetrating faster than higher‐µelectrons. These results suggest nondiffusive radial transport as the main mechanism of electron deep penetrations. In comparison, proton deep penetration happens at a slower pace. Statistics also show that the electron PSD radial gradient is much steeper than protons prior to deep penetration events, which can be responsible for these differential behaviors of electron and proton deep penetrations. Statistical analysis reveals that energetic electron deep penetration to L< 4 occurs more frequently, deeply, and faster than protonsMost electron deep penetrations occurred on a time scale of several hours, indicating nondiffusive radial transport as the main mechanismThe steeper phase space density radial gradient of electrons compared to protons contributes to the differential deep penetration of different species Statistical analysis reveals that energetic electron deep penetration to L< 4 occurs more frequently, deeply, and faster than protons Most electron deep penetrations occurred on a time scale of several hours, indicating nondiffusive radial transport as the main mechanism The steeper phase space density radial gradient of electrons compared to protons contributes to the differential deep penetration of different species
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- 2023
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27. The GOES-16 Spacecraft Science Magnetometer.
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Loto'aniu, T. M., Redmon, R. J., Califf, S., Singer, H. J., Rowland, W., Macintyre, S., Chastain, C., Dence, R., Bailey, R., Shoemaker, E., Rich, F. J., Chu, D., Early, D., Kronenwetter, J., and Todirita, M.
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MAGNETOMETERS ,SCIENTIFIC apparatus & instruments ,SPACE environment ,GEOMAGNETISM ,MAGNETIC fields ,ARTIFICIAL satellite launching ,ARTIFICIAL satellites - Abstract
Since their inception in the 1970s, the NOAA Geostationary Operational Environmental Satellite (GOES) system has monitored the sources of space weather on the sun and the effects of space weather at Earth. These observations are important for providing forecasts, warnings and alerts to many customers, including satellite operators, the power utilities, and NASA's human activities in space. The GOES magnetometer provides observations of the geomagnetic field, which can be the first indication that significant space weather has reached Earth. In addition, the magnetic field observations are used to identify and forecast the severity of the space weather activity. This paper reviews the capabilities of the GOES-16 magnetometer (MAG) and presents initial post-launch calibration/validation results including issues found in the data. The GOES-16 MAG requirements and capabilities are similar to those for previously flown instruments, measuring three components of the geomagnetic field but with an improved sampling rate of 10 samples/second. The MAG data are low-pass filtered with a 2.5 Hz cutoff compared to the 0.5 Hz cutoff of previous GOES magnetometers. The MAG is composed of two magnetometers, an inboard (closer to spacecraft bus) and outboard (on tip of boom) magnetometer. Presented are the science and instrument requirements, ground and initial on-orbit instrument calibration and data validation. The on-orbit analysis found magnetic contamination along with temperature dependency effects that resulted in unexpected instrument noise and decreased accuracy, with the issues generally more significant on the inboard magnetometer. The outboard sensor was used for initial analysis of MAG performance. Preliminary comparison, excluding arcjet firing periods, between the outboard magnetometer and the GOES-14 magnetometer found a statistical difference of 5 nT at 3 σ for the total field. This comparison does not consider inaccuracies in the GOES-14 magnetometer. Future studies will focus on optimizing the outboard sensor performance. [ABSTRACT FROM AUTHOR]
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- 2019
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28. Van Allen Probes Measurements of Energetic Particle Deep Penetration Into the Low L Region (L< 4) During the Storm on 8 April 2016
- Author
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Zhao, H., Baker, D. N., Califf, S., Li, X., Jaynes, A. N., Leonard, T., Kanekal, S. G., Blake, J. B., Fennell, J. F., Claudepierre, S. G., Turner, D. L., Reeves, G. D., and Spence, H. E.
- Abstract
Using measurements from the Van Allen Probes, a penetration event of tens to hundreds of keV electrons and tens of keV protons into the low L shells (L< 4) is studied. Timing and magnetic local time (MLT) differences of energetic particle deep penetration are unveiled and underlying physical processes are examined. During this event, both proton and electron penetrations are MLT asymmetric. The observed MLT difference of proton penetration is consistent with convection of plasma sheet protons, suggesting enhanced convection during geomagnetic active times to be the cause of energetic proton deep penetration during this event. The observed MLT difference of tens to hundreds of keV electron penetration is completely different from tens of keV protons and cannot be well explained by inward radial diffusion, convection of plasma sheet electrons, or transport of trapped electrons by enhanced convection electric field represented by the Volland‐Stern model or a uniform dawn‐dusk electric field model based on the electric field measurements. It suggests that the underlying physical mechanism responsible for energetic electron deep penetration, which is very important for fully understanding energetic electron dynamics in the low L shells, should be MLT localized. Timing and MLT differences of particle deep penetration are unveiled using conjunctive measurements from Van Allen Probes during one eventMLT difference of proton deep penetration during this event is consistent with the convection of near‐Earth plasma sheet protonsMLT difference of electron penetration during this event is different from protons and suggests the existence of MLT‐localized mechanism
- Published
- 2017
- Full Text
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