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  • 1
    Publication Date: 2011-12-07
    Description: The Cascades-2 sounding rocket was launched on 20 March 2009 at 11:04:00 UT from the Poker Flat Research Range in Alaska, and flew across a series of poleward boundary intensifications (PBIs). The rocket initially crosses a diffuse arc, then crosses the equatorward extent of one PBI (a streamer), and finally crosses the initiation of a separate PBI before entering the polar cap. Each of the crossings have fundamentally different in situ electron energy and pitch angle structure, and different ground optics images of visible aurora. It is found that the diffuse arc has a quasi-static acceleration mechanism, and the intensification at the poleward boundary has an Alfvénic acceleration mechanism. The streamer shows characteristics of both types of acceleration. PFISR data provide ionospheric context for the rocket observations. Three THEMIS satellites in close conjunction with the rocket foot point show earthward flows and slight dipolarizations in the magnetotail associated with the in situ observations of PBI activity. An important goal of the Cascades-2 study is to bring together the different observational communities (rocket, ground cameras, ground radar, satellite) with the same case study. The Cascades-2 experiment is the first sounding rocket observation of a PBI sequence, enabling a detailed investigation of the electron signatures and optical aurora associated with various stages of a PBI sequence as it evolves from an Alfvénic to a more quasi-static structure.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 2
    Publication Date: 2015-10-06
    Description: A detailed, in-situ study of field-aligned current (FAC) structure in a transient, substorm expansion phase auroral arc is conducted using electric field, magnetometer, and electron density measurements from the MICA sounding rocket, launched from Poker Flat, AK. These data are supplemented with larger-scale, contextual measurements from a heterogeneous collection of ground-based instruments including the Poker Flat incoherent scatter radar and nearby scanning doppler imagers and filtered allsky cameras. An electrostatic ionospheric modeling case study of this event is also constructed by using available data (neutral winds, electron precipitation, and electric fields) to constrain model initial and boundary conditions. MICA magnetometer data are converted into FAC measurements using a sheet-current approximation, and show an up-down current pair, with small-scale current density and Poynting flux structures in the downward current channel. Model results are able to roughly recreate only the large-scale features of the field-aligned currents, suggesting that observed small-scale structures may be due to ionospheric feedback processes not encapsulated by the electrostatic model. The model is also used to assess the contributions of various processes to total FAC, and suggests that both conductance gradients and neutral dynamos may contribute significantly to FACs in a narrow region where the current transitions from upward to downward. Comparison of PFISR versus in situ electric field estimates illustrates the high sensitivity of FAC estimates to measurement resolution.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 3
    Publication Date: 2014-03-13
    Description: Auroral ionospheric F-region density depletions observed by PFISR (Poker Flat Incoherent Scatter Radar) during the MICA (Magnetosphere-Ionosphere Coupling in the Alfvén Resonator) sounding rocket campaign are critically examined alongside complementary numerical simulations. Particular processes of interest include cavity formation due to intense frictional heating and Pedersen drifts, evolution in the presence of structured precipitation, and refilling due to impact ionization and downflows. Our analysis uses an ionospheric fluid model which solves conservation of mass, momentum, and energy equations for all major ionospheric species. These fluid equations are coupled to an electrostatic current continuity equation to self-consistently describe auroral electric fields. Energetic electron precipitation inputs for the model are specified by inverting optical data, and electric field boundary conditions are obtained from direct PFISR measurements. Thus, the model is driven in as realistic a manner as possible. Both ISR data and simulations indicate that the conversion of the F-region plasma to molecular ions and subsequent recombination is the dominant process contributing to the formation of the observed cavities, all of which occur in conjuction with electric fields exceeding ∼ 90 mV/m. Furthermore, the cavities often persist several minutes past the point when the frictional heating stops. Impact ionization and field-aligned plasma flows modulate the cavity depth in a significant way, but are of secondary importance to the molecular generation process. Informal comparisons of the ISR density and temperature fits to the model verify that the simulations reproduce most of the observed cavity features to a reasonable level of detail.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
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  • 4
    Publication Date: 2012-10-10
    Description: VHF coherent scatter radar observations of an auroral substorm over Alaska are analyzed in the context of multibeam incoherent scatter plasma density and drifts data and green-line all-sky optical imagery. Coherent scatter arises from Farley Buneman waves which are excited in the E region whenever the convection electric field is greater than about 20 mV/m. Aperture synthesis radar imaging and other aspects of the methodology facilitate the precise spatial registration of the coherent scatter with coincident optical and incoherent scatter radar measurements. Discrete auroral arcs were found to separate diffuse regions of coherent backscatter and, sometimes, to align with the boundaries of those regions. At other times, auroral arcs and torches lined up adjacent to discrete, structured regions or radar backscatter. Drastic variations in the Doppler shifts of the coherent scatter from one side of the auroral forms to the other suggest the presence of field-aligned currents. An empirical formula based on previous studies but adapted to account approximately for the effects of wave turning was used to estimate the convection electric field from the moments of the coherent scatter Doppler spectra. Line-of-sight F region plasma drift measurements from the Poker Flat Incoherent Scatter Radar (PFISR) were found to be in reasonable agreement with these convection field estimates. Reasons why the empirical formulas may be expected to hold are discussed.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 5
    Publication Date: 2012-11-03
    Description: The Cascades2 auroral sounding rocket provides a case study for comparing multipoint in situ ionospheric observations of a nightside auroral poleward boundary intensification with ground-based optical observations of the same event. Cascades2 was launched northward from Poker Flat Alaska on 20 March 2009 at 11:04 UT. The 13 min flight reached an apogee of 564 km over the northern coast of Alaska. The experiment included a five-payload array of in situ instrumentation, ground cameras at three different points under the trajectory, multiple ground magnetometers, the Poker Flat Incoherent Scatter Radar (PFISR) radar, and the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft in the magnetotail. The rays of the poleward boundary intensification (PBI) curtain have along-arc motions of 8.5 km/s and along-arc spacings of 16 km. Modulated maximum energy envelopes and energy fluxes of the associated electron precipitation correspond to this spatial structure of the visible rays. The electron precipitation is additionally modulated at a higher frequency, and velocity dispersion analysis of these 8 Hz signatures implies Alfvénic wave-particle acceleration of an ambient ionospheric electron source occurring a few hundred km above the observation point. These observations parameterize the curtain of Alfvénic activity above the PBI event, both in the dispersive ionosphere and in the magnetotail reconnection region. The along-arc variations in brightness correspond to variations in precipitating electron energy flux interpreted as an along-arc modulation of the maximum energy of the Alfvénic wave-particle acceleration process; this is a new interpretation of the formation of rayed structures in auroral curtains. We consider the various possible magnetospheric and ionospheric drivers for the control of the observed along-arc structuring and motions.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 6
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    Kottyan, L. C., Zoller, E. E., Bene, J., Lu, X., Kelly, J. A., Rupert, A. M., Lessard, C. J., Vaughn, S. E., Marion, M., Weirauch, M. T., Namjou, B., Adler, A., Rasmussen, A., Glenn, S., Montgomery, C. G., Hirschfield, G. M., Xie, G., Coltescu, C., Amos, C., Li, H., Ice, J. A., Nath, S. K., Mariette, X., Bowman, S., for UK Primary Sjogren's Syndrome Registry, Rischmueller, M., Lester, S., Brun, J. G., Goransson, L. G., Harboe, E., Omdal, R., Cunninghame-Graham, D. S., Vyse, T., Miceli-Richard, C., Brennan, M. T., Lessard, J. A., Wahren-Herlenius, M., Kvarnstrom, M., Illei, G. G., Witte, T., Jonsson, R., Eriksson, P., Nordmark, G., Ng, W.-F., for UK Primary Sjogren's Syndrome Registry, Anaya, J.-M., Rhodus, N. L., Segal, B. M., Merrill, J. T., James, J. A., Guthridge, J. M., Hal Scofield, R., Alarcon-Riquelme, M., Bae, S.-C., Boackle, S. A., Criswell, L. A., Gilkeson, G., Kamen, D. L., Jacob, C. O., Kimberly, R., Brown, E., Edberg, J., Alarcon, G. S., Reveille, J. D., Vila, L. M., Petri, M., Ramsey-Goldman, R., Freedman, B. I., Niewold, T., Stevens, A. M., Tsao, B. P., Ying, J., Mayes, M. D., Gorlova, O. Y., Wakeland, W., Radstake, T., Martin, E., Martin, J., Siminovitch, K., Moser Sivils, K. L., Gaffney, P. M., Langefeld, C. D., Harley, J. B., Kaufman, K. M.
    Oxford University Press
    Publication Date: 2014-12-24
    Description: Exploiting genotyping, DNA sequencing, imputation and trans-ancestral mapping, we used Bayesian and frequentist approaches to model the IRF5 – TNPO3 locus association, now implicated in two immunotherapies and seven autoimmune diseases. Specifically, in systemic lupus erythematosus (SLE), we resolved separate associations in the IRF5 promoter (all ancestries) and with an extended European haplotype. We captured 3230 IRF5 – TNPO3 high-quality, common variants across 5 ethnicities in 8395 SLE cases and 7367 controls. The genetic effect from the IRF5 promoter can be explained by any one of four variants in 5.7 kb ( P -value meta = 6 x 10 –49 ; OR = 1.38–1.97). The second genetic effect spanned an 85.5-kb, 24-variant haplotype that included the genes IRF5 and TNPO3 ( P -values EU = 10 –27 –10 –32 , OR = 1.7–1.81). Many variants at the IRF5 locus with previously assigned biological function are not members of either final credible set of potential causal variants identified herein. In addition to the known biologically functional variants, we demonstrated that the risk allele of rs4728142, a variant in the promoter among the lowest frequentist probability and highest Bayesian posterior probability, was correlated with IRF5 expression and differentially binds the transcription factor ZBTB3. Our analytical strategy provides a novel framework for future studies aimed at dissecting etiological genetic effects. Finally, both SLE elements of the statistical model appear to operate in Sjögren's syndrome and systemic sclerosis whereas only the IRF5–TNPO3 gene-spanning haplotype is associated with primary biliary cirrhosis, demonstrating the nuance of similarity and difference in autoimmune disease risk mechanisms at IRF5 – TNPO3 .
    Print ISSN: 0964-6906
    Electronic ISSN: 1460-2083
    Topics: Biology , Medicine
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  • 7
    Publication Date: 2014-11-11
    Description: Lung diseases such as chronic obstructive pulmonary disease and pulmonary fibrosis involve the progressive and inexorable destruction of oxygen exchange surfaces and airways, and have emerged as a leading cause of death worldwide. Mitigating therapies, aside from impractical organ transplantation, remain limited and the possibility of regenerative medicine has lacked empirical support. However, it is clinically known that patients who survive sudden, massive loss of lung tissue from necrotizing pneumonia or acute respiratory distress syndrome often recover full pulmonary function within six months. Correspondingly, we recently demonstrated lung regeneration in mice following H1N1 influenza virus infection, and linked distal airway stem cells expressing Trp63 (p63) and keratin 5, called DASC(p63/Krt5), to this process. Here we show that pre-existing, intrinsically committed DASC(p63/Krt5) undergo a proliferative expansion in response to influenza-induced lung damage, and assemble into nascent alveoli at sites of interstitial lung inflammation. We also show that the selective ablation of DASC(p63/Krt5) in vivo prevents this regeneration, leading to pre-fibrotic lesions and deficient oxygen exchange. Finally, we demonstrate that single DASC(p63/Krt5)-derived pedigrees differentiate to type I and type II pneumocytes as well as bronchiolar secretory cells following transplantation to infected lung and also minimize the structural consequences of endogenous stem cell loss on this process. The ability to propagate these cells in culture while maintaining their intrinsic lineage commitment suggests their potential in stem cell-based therapies for acute and chronic lung diseases.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zuo, Wei -- Zhang, Ting -- Wu, Daniel Zheng'An -- Guan, Shou Ping -- Liew, Audrey-Ann -- Yamamoto, Yusuke -- Wang, Xia -- Lim, Siew Joo -- Vincent, Matthew -- Lessard, Mark -- Crum, Christopher P -- Xian, Wa -- McKeon, Frank -- England -- Nature. 2015 Jan 29;517(7536):616-20. doi: 10.1038/nature13903. Epub 2014 Nov 12.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Genome Institute of Singapore, A-STAR, 138672 Singapore. ; The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut 06032, USA. ; Advanced Cell Technologies, Marlborough, Massachusetts 01752, USA. ; The Jackson Laboratory, Bar Harbor, Maine 04609, USA. ; Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA. ; 1] Genome Institute of Singapore, A-STAR, 138672 Singapore [2] The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut 06032, USA [3] Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA [4] Department of Medicine, National University Health System, 119228 Singapore [5] Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, Connecticut 06030, USA. ; 1] Genome Institute of Singapore, A-STAR, 138672 Singapore [2] The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut 06032, USA [3] Department of Medicine, National University Health System, 119228 Singapore.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25383540" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Bronchioles/cytology/virology ; Cell Differentiation ; Cell Lineage ; Cell Proliferation ; Dogs ; Humans ; Influenza A Virus, H1N1 Subtype/pathogenicity ; Keratin-5/*metabolism ; Lung/*cytology/pathology/*physiology/virology ; Madin Darby Canine Kidney Cells ; Mice ; Orthomyxoviridae Infections/metabolism/pathology/virology ; Oxygen/metabolism ; Pedigree ; Phosphoproteins/*metabolism ; Pneumonia/metabolism/pathology/virology ; Pulmonary Alveoli/cytology/pathology/virology ; Re-Epithelialization ; *Regeneration ; Stem Cell Transplantation ; Stem Cells/*cytology/*metabolism ; Trans-Activators/*metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 8
    Publication Date: 1997-11-21
    Description: The Janus family of tyrosine kinases (JAK) plays an essential role in development and in coupling cytokine receptors to downstream intracellular signaling events. A t(9;12)(p24;p13) chromosomal translocation in a T cell childhood acute lymphoblastic leukemia patient was characterized and shown to fuse the 3' portion of JAK2 to the 5' region of TEL, a gene encoding a member of the ETS transcription factor family. The TEL-JAK2 fusion protein includes the catalytic domain of JAK2 and the TEL-specific oligomerization domain. TEL-induced oligomerization of TEL-JAK2 resulted in the constitutive activation of its tyrosine kinase activity and conferred cytokine-independent proliferation to the interleukin-3-dependent Ba/F3 hematopoietic cell line.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lacronique, V -- Boureux, A -- Valle, V D -- Poirel, H -- Quang, C T -- Mauchauffe, M -- Berthou, C -- Lessard, M -- Berger, R -- Ghysdael, J -- Bernard, O A -- New York, N.Y. -- Science. 1997 Nov 14;278(5341):1309-12.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉U 301 de l'Institut National de la Sante et de la Recherche Medicale and SD 401 No. 301 CNRS, Institut de Genetique Moleculaire, 27 rue Juliette Dodu, 75010 Paris, France.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/9360930" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Base Sequence ; Biopolymers ; Cell Division ; Cell Line ; Child, Preschool ; DNA-Binding Proteins/chemistry/genetics/metabolism ; Enzyme Activation ; Humans ; Interleukin-3/physiology ; Janus Kinase 2 ; Leukemia-Lymphoma, Adult T-Cell/genetics/*metabolism ; Male ; Mice ; *Milk Proteins ; Molecular Sequence Data ; Oncogene Proteins, Fusion/chemistry/genetics/*metabolism ; Phosphorylation ; Protein-Tyrosine Kinases/chemistry/genetics/*metabolism ; *Proto-Oncogene Proteins ; Proto-Oncogene Proteins c-ets ; *Repressor Proteins ; STAT5 Transcription Factor ; Signal Transduction ; Trans-Activators/metabolism ; Transcription Factors/chemistry/genetics/metabolism ; Transfection ; Translocation, Genetic
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 9
    Publication Date: 2013-01-03
    Description: [1]  The Cascades2 auroral sounding rocket provides a case study for comparing multipoint in situ ionospheric observations of a nightside auroral poleward boundary intensification with ground-based optical observations of the same event. Cascades2 was launched northward from Poker Flat Alaska on 20 March 2009 at 11:04 UT. The 13 min flight reached an apogee of 564 km over the northern coast of Alaska. The experiment included a five-payload array of in situ instrumentation, ground cameras at three different points under the trajectory, multiple ground magnetometers, the Poker Flat Incoherent Scatter Radar (PFISR) radar, and the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft in the magnetotail. The rays of the poleward boundary intensification (PBI) curtain have along-arc motions of 8.5 km/s and along-arc spacings of 16 km. Modulated maximum energy envelopes and energy fluxes of the associated electron precipitation correspond to this spatial structure of the visible rays. The electron precipitation is additionally modulated at a higher frequency, and velocity dispersion analysis of these 8 Hz signatures implies Alfvénic wave-particle acceleration of an ambient ionospheric electron source occurring a few hundred km above the observation point. These observations parameterize the curtain of Alfvénic activity above the PBI event, both in the dispersive ionosphere and in the magnetotail reconnection region. The along-arc variations in brightness correspond to variations in precipitating electron energy flux interpreted as an along-arc modulation of the maximum energy of the Alfvénic wave-particle acceleration process; this is a new interpretation of the formation of rayed structures in auroral curtains. We consider the various possible magnetospheric and ionospheric drivers for the control of the observed along-arc structuring and motions.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 10
    Publication Date: 2019
    Description: Abstract This study examines cumulative effects of a series of poleward moving auroral forms on ion upflow and downflow. These effects are investigated using an ionospheric model with inputs derived from the Rocket Experiment for Neutral Upwelling 2 (RENU2) sounding rocket campaign. Auroral precipitation inputs are constrained by all‐sky imager brightness values resulting in significant latitudinal structuring in simulated ionospheric upflows due to transient forcing. For contrast, a case with steady forcing generates almost double the O+ upflow transport through 1,000 km when compared to poleward moving auroral form‐like structures. At high altitudes, model results show a spread in upflow response time dependent on ion mass, with molecular ions responding slower than atomic ions by several minutes. While the modeled auroral precipitation is not strong enough to accelerate ions to escape velocities, source populations available for higher‐altitude energization processes are greatly impacted by variable forcing exhibited by the RENU2 event.
    Print ISSN: 0094-8276
    Electronic ISSN: 1944-8007
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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