Ionospheric electron number densities from CUTLASS dual-frequency velocity measurements using artificial backscatter over EISCAT

Using quasi-simultaneous line-of-sight velocity measurements at multiple frequencies from the Hankasalmi Cooperative UK Twin Auroral Sounding System (CUTLASS) on the Super Dual Auroral Radar Network (SuperDARN), we calculate electron number densities using a derivation outlined in Gillies et al. (2010, 2012). Backscatter targets were generated using the European Incoherent Scatter (EISCAT) ionospheric modification facility at Tromsø, Norway. We use two methods on two case studies. The first approach is to use the dual-frequency capability on CUTLASS and compare line-of-sight velocities between frequencies with a MHz or greater difference. The other method used the kHz frequency shifts automatically made by the SuperDARN radar during routine operations. Using ray tracing to obtain the approximate altitude of the backscatter, we demonstrate that for both methods, SuperDARN significantly overestimates Ne compared to those obtained from the EISCAT incoherent scatter radar over the same time period. The discrepancy between the Ne measurements of both radars may be largely due to SuperDARN sensitivity to backscatter produced by localized density irregularities which obscure the background levels

Postmidnight depletion of the high‐energy tail of the quiet plasmasphere

The Van Allen Probes Helium Oxygen Proton Electron (HOPE) instrument measures the high‐energy tail of the thermal plasmasphere allowing study of topside ionosphere and inner magnetosphere coupling. We statistically analyze a 22 month period of HOPE data, looking at quiet times with a Kp index of less than 3. We investigate the high‐energy range of the plasmasphere, which consists of ions at energies between 1 and 10 eV and contains approximately 5% of total plasmaspheric density. Both the fluxes and partial plasma densities over this energy range show H+ is depleted the most in the postmidnight sector (1–4 magnetic local time), followed by O+ and then He+. The relative depletion of each species across the postmidnight sector is not ordered by mass, which reveals ionospheric influence. We compare our results with keV energy electron data from HOPE and the Van Allen Probes Electric Fields and Waves instrument spacecraft potential to rule out spacecraft charging. Our conclusion is that the postmidnight ion disappearance is due to diurnal ionospheric temperature variation and charge exchange processes.Key PointsOne to ten eV ion depletion in quiet time postmidnight sectorDepletion varies by ion species not ordered by massStrong diurnal variation in high‐energy tail of plasmaspherePeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111226/1/jgra51633.pd

Ionospheric electron number densities from CUTLASS dual-frequency velocity measurements using artificial backscatter over EISCAT

Using quasi‐simultaneous line‐of‐sight velocity measurements at multiple frequencies from the Hankasalmi Cooperative UK Twin Auroral Sounding System (CUTLASS) on the Super Dual Auroral Radar Network (SuperDARN), we calculate electron number densities using a derivation outlined in Gillies et al. (2010, 2012). Backscatter targets were generated using the European Incoherent Scatter (EISCAT) ionospheric modification facility at Tromsø, Norway. We use two methods on two case studies. The first approach is to use the dual‐frequency capability on CUTLASS and compare line‐of‐sight velocities between frequencies with a MHz or greater difference. The other method used the kHz frequency shifts automatically made by the SuperDARN radar during routine operations. Using ray tracing to obtain the approximate altitude of the backscatter, we demonstrate that for both methods, SuperDARN significantly overestimates Ne compared to those obtained from the EISCAT incoherent scatter radar over the same time period. The discrepancy between the Ne measurements of both radars may be largely due to SuperDARN sensitivity to backscatter produced by localized density irregularities which obscure the background levels

Local time variations of highâ energy plasmaspheric ion pitch angle distributions

Recent observations from the Van Allen Probes Helium Oxygen Proton Electron (HOPE) instrument revealed a persistent depletion in the 1â 10 eV ion population in the postmidnight sector during quiet times in the 2 < L < 3 region. This study explores the source of this ion depletion by developing an algorithm to classify 26 months of pitch angle distributions measured by the HOPE instrument. We correct the HOPE low energy fluxes for spacecraft potential using measurements from the Electric Field and Waves (EFW) instrument. A high percentage of low count pitch angle distributions is found in the postmidnight sector coupled with a low percentage of ion distributions peaked perpendicular to the field line. A peak in loss cone distributions in the dusk sector is also observed. These results characterize the nature of the dearth of the near 90° pitch angle 1â 10 eV ion population in the nearâ Earth postmidnight sector. This study also shows, for the first time, lowâ energy HOPE differential number fluxes corrected for spacecraft potential and 1â 10 eV H+ fluxes at different levels of geomagnetic activity.Key PointsDeveloped new pitch angle sorting algorithm for Van Allen ProbesFound 90 degree pitch angle population depletion in nearâ Earth postmidnight sectorCorrected low energy HOPE ion fluxes for spacecraft potentialPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134226/1/jgra52723_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134226/2/jgra52723.pd

Hiss or equatorial noise? Ambiguities in analyzing suprathermal ion plasma wave resonance

Previous studies have shown that lowâ energy ion heating occurs in the magnetosphere due to strong equatorial noise emission. Observations from the Van Allen Probes Helium Oxygen Proton Electron (HOPE) instrument recently determined that there was a depletion in the 1â 10 eV ion population in the postmidnight sector of Earth during quiet times at L < 3. The diurnal variation of equatorially mirroring 1â 10 eV H+ ions at 2 < L < 3 is connected with similar diurnal variation in the electric field component of plasma waves ranging between 150 and 600 Hz. Measurements from the Van Allen Probes Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) data set are used to analyze waves of this frequency in nearâ Earth space. However, when we examine the polarization of the waves in the 150 to 600 Hz range in the equatorial plane, the majority are rightâ hand polarized plasmaspheric hiss waves. The 1â 10 eV H+ equatorially mirroring population does not interact with rightâ hand waves, despite a strong statistical relationship suggesting that the two are linked. We present evidence supporting the relationship, both in our own work and the literature, but we ultimately conclude that the 1â 10 eV H+ heating is not related to the strong enhancement of 150 to 600 Hz waves.Key PointsA 1â 10 eV ion loss from plasma wave interactionHighâ amplitude plasma waves seem like probable candidatePolarization analysis reveals that the waves are hissPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134763/1/jgra52995.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134763/2/jgra52995_am.pd

Risk of Zika microcephaly correlates with features of maternal antibodies

Submitted by Ana Maria Fiscina Sampaio ([email protected]) on 2019-10-10T12:26:15Z No. of bitstreams: 1 Robbiani F D ...Risk.pdf: 2296966 bytes, checksum: 5e47aca9208f3f35c969fd82960279f4 (MD5)Approved for entry into archive by Ana Maria Fiscina Sampaio ([email protected]) on 2019-10-10T13:32:42Z (GMT) No. of bitstreams: 1 Robbiani F D ...Risk.pdf: 2296966 bytes, checksum: 5e47aca9208f3f35c969fd82960279f4 (MD5)Made available in DSpace on 2019-10-10T13:32:42Z (GMT). No. of bitstreams: 1 Robbiani F D ...Risk.pdf: 2296966 bytes, checksum: 5e47aca9208f3f35c969fd82960279f4 (MD5) Previous issue date: 2019-01-07National Institutes of Health grants 5R01AI121207, R01TW009504, and R25TW009338 to A.I. Ko; National Institutes of Health pilot awards U19AI111825 and UL1TR001866 to D.F. Robbiani; National Institutes of Health grants R01AI037526, UM1AI100663, U19AI111825, UL1TR001866, and P01AI138938 to M.C. Nussenzweig; National Institutes of Health grants R01AI124690 and U19AI057229 (Cooperative Center for Human Immunology pilot project); The Rockefeller University Development Office and anonymous donors (to C.M. Rice); Fundação de Amparo `a Pesquisa do Estado da Bahia grant PET0021/2016 (to M.G. Reis); National Institutes of Health grant R21AI129479-Supplement (to K.K.A. Van Rompay) and the National Institutes of Health Office of Research Infrastructure Programs/OD (P51OD011107 to the CNPRC); the United States Food and Drug Administration contract HHSF223201610542P (to L.L. Coffey); National Institutes of Health grants R01AI100989 and R01AI133976 (to L. Rajagopal and K.M. Adams Waldorf); and National Institutes of Health grants AI083019 and AI104002 (to M. Gale Jr.) and grant P51OD010425 to the WaNPRC (to K.M. Adams Waldorf, J. Tisoncik-Go, and M. Gale Jr.). Studies at WNPRC were supported by DHHS/PHS/National Institutes of Health grant R01Al116382-01A1 (to D.H. O’Connor), in part by the National Institutes of Health Office of Research Infrastructure Programs/OD (grant P51OD011106) awarded toWNPRC, at a facility constructed in part with support from Research Facilities Improvement Programgrants RR15459-01 and RR020141-01; and National Institutes of Health core and pilot grant P51 OD011092 and grants R21-HD091032 and R01-HD08633 (to ONPRC). P.F.C. Vasconcelos was supported by Conselho Nacional de Desenvolvimento Cientifico e Tecnológico (projects 303999/2016-0, 439971/20016-0, and 440405/2016-5) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Zika fast-track).The Rockefeller University. Laboratory of Molecular Immunology. New York, NY, USA.The Rockefeller University. Laboratory of Molecular Immunology. New York, NY, USA / Universidade Federal do Rio de Janeiro. Faculdade de Farmácia. Rio de Janeiro, RJ, Brasil.Yale School of Public Health. Department of Epidemiology of Microbial Diseases. New Haven / Universidade Federal da Bahia. Faculdade de Medicina. Instituto da Saúde Coletiva. Salvador, BA, Brasil.Fudan University. School of Basic Medical Sciences. Shanghai Medical College. Key Laboratory of Medical Molecular Virology. Shanghai, China.The Rockefeller University. Laboratory of Molecular Immunology. New York, NY, USA.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil.Yale School of Public Health. Department of Epidemiology of Microbial Diseases. New Haven.Secretaria de Saúde do Estado da Bahia. Hospital Geral Roberto Santos. Salvador, BA, Brasil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil.Yale School of Public Health. Department of Epidemiology of Microbial Diseases. New Haven.Secretaria de Saúde do Estado da Bahia. Hospital Geral Roberto Santos. Salvador, BA, Brasil.Secretaria de Saúde do Estado da Bahia. Hospital Geral Roberto Santos. Salvador, BA, Brasil / Universidade Federal de São Paulo. São Paulo, SP, Brasil.Universidade Federal da Bahia. Faculdade de Medicina. Instituto da Saúde Coletiva. Salvador, BA, Brasil.Secretaria de Saúde do Estado da Bahia. Hospital Geral Roberto Santos. Salvador, BA, Brasil.Secretaria de Saúde do Estado da Bahia. Hospital Geral Roberto Santos. Salvador, BA, Brasil.Secretaria de Saúde do Estado da Bahia. Hospital Geral Roberto Santos. Salvador, BA, Brasil.Secretaria de Saúde do Estado da Bahia. Hospital Geral Roberto Santos. Salvador, BA, Brasil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil.Universidade Federal da Bahia. Faculdade de Medicina. Instituto da Saúde Coletiva. Salvador, BA, Brasil.Ministério da Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.The Rockefeller University. Laboratory of Molecular Immunology. New York, NY.Universidade Federal do Rio de Janeiro. Faculdade de Farmácia. Rio de Janeiro, RJ, Brasil.Universidade Federal do Rio de Janeiro. Faculdade de Farmácia. Rio de Janeiro, RJ, Brasil.The Rockefeller University. Laboratory of Molecular Immunology. New York, NY, USA.Universidade Federal de São Paulo. São Paulo, SP, Brasil.Hospital Santo Amaro. Salvador, BA, Brasil.Hospital Santo Amaro. Salvador, BA, Brasil.Hospital Santo Amaro. Salvador, BA, Brasil.Hospital Aliança. Salvador, BA, Brasil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / Yale School of Public Health. Department of Epidemiology of Microbial Diseases. New Haven / Universidade Federal da Bahia. Faculdade de Medicina. Instituto da Saúde Coletiva. Salvador, BA, Brasil.University of California. California National Primate Research Center. Davis, Davis, CA, USA.University of California. School of Veterinary Medicine. Department of Pathology, Microbiology, and Immunology. Davis, Davis, CA, USA.Washington National Primate Research Center. Seattle, WA, USA / University of Washington. Center for Innate Immunity and Immune Disease. Seattle, WA, USA / University of Washington. Department of Immunology. Seattle, WA, USA.Washington National Primate Research Center. Seattle, WA / University of Washington. Center for Innate Immunity and Immune Disease. Seattle, WA, USA / University of Washington. Department of Immunology. Seattle, WA, USA / University of Washington. Department of Global Health. Seattle, WA, USA.University of Washington. Department of Global Health. Seattle, WA, USA / University of Washington. Department of Pediatrics. Seattle, WA, USA / Seattle Children’s Research Institute. Center for Global Infectious Disease Research. Seattle, WA, USA.Washington National Primate Research Center. Seattle, WA, USA / University of Washington. Center for Innate Immunity and Immune Disease. Seattle, WA, USA / University of Washington. Department of Global Health. Seattle, WA, USA / University of Washington. Department of Obstetrics and Gynecology. Seattle, WA, USA.University of Wisconsin-Madison. Department of Pathology and Laboratory Medicine. Madison, WI, USA.University of Wisconsin-Madison. Wisconsin National Primate Research Center. Madison, WI, USA.University of Wisconsin-Madison. Wisconsin National Primate Research Center. Madison, WI, USA.University of Wisconsin-Madison. Department of Pathology and Laboratory Medicine. Madison, WI, USA.Oregon National Primate Research Center. Division of Reproductive and Developmental Sciences. Beaverton, OR, USA.Oregon National Primate Research Center. Division of Pathobiology and Immunology. Beaverton, OR, USA / Oregon Health and Science University. Vaccine and Gene Therapy Institute. Portland, OR, USA.Oregon Health and Science University. Vaccine and Gene Therapy Institute. Portland, OR, USA.Oregon National Primate Research Center. Pathology Services Unit, Division of Comparative Medicine. Beaverton, OR, USA.Oregon National Primate Research Center. Division of Pathobiology and Immunology. Beaverton, OR, USA.Oregon National Primate Research Center. Division of Reproductive and Developmental Sciences. Beaverton, OR, USA.Oregon National Primate Research Center. Division of Reproductive and Developmental Sciences. Beaverton, OR, USA / Oregon Health and Science University. Department of Obstetrics and Gynecology. Portland, OR, USA.Oregon National Primate Research Center. Division of Reproductive and Developmental Sciences. Beaverton, OR, USA.Oregon National Primate Research Center. Division of Pathobiology and Immunology. Beaverton, OR, USA / Oregon Health and Science University. Vaccine and Gene Therapy Institute. Portland, OR, USA.Oregon National Primate Research Center. Division of Pathobiology and Immunology. Beaverton, OR, USA / Oregon Health and Science University. Vaccine and Gene Therapy Institute. Portland, OR, USA.Universidade Federal do Rio de Janeiro. Faculdade de Farmácia. Rio de Janeiro, RJ, Brasil.Universidade Federal do Rio de Janeiro. Faculdade de Farmácia. Rio de Janeiro, RJ, Brasil.Universidade Federal da Bahia. Faculdade de Medicina. Instituto da Saúde Coletiva. Salvador, BA, Brasil.University of California. California National Primate Research Center. Davis, Davis, CA, USA / University of California. School of Veterinary Medicine. Department of Pathology, Microbiology, and Immunology. Davis, Davis, CA, USA.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / Yale School of Public Health. Department of Epidemiology of Microbial Diseases. New Haven, USA.The Rockefeller University. Laboratory of Molecular Immunology. New York, NY, USA / The Rockefeller University. Howard Hughes Medical Institute. New York, NY, USA.Zika virus (ZIKV) infection during pregnancy causes congenital abnormalities, including microcephaly. However, rates vary widely, and the contributing risk factors remain unclear. We examined the serum antibody response to ZIKV and other flaviviruses in Brazilian women giving birth during the 2015-2016 outbreak. Infected pregnancies with intermediate or higher ZIKV antibody enhancement titers were at increased risk to give birth to microcephalic infants compared with those with lower titers (P < 0.0001). Similarly, analysis of ZIKV-infected pregnant macaques revealed that fetal brain damage was more frequent in mothers with higher enhancement titers. Thus, features of the maternal antibodies are associated with and may contribute to the genesis of ZIKV-associated microcephaly