24 research outputs found

    Martian low‐altitude magnetic topology deduced from MAVEN/SWEA observations

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    The Mars Atmosphere and Volatile Evolution mission has obtained comprehensive particle and magnetic field measurements. The Solar Wind Electron Analyzer provides electron energy‐pitch angle distributions along the spacecraft trajectory that can be used to infer magnetic topology. This study presents pitch angle‐resolved electron energy shape parameters that can distinguish photoelectrons from solar wind electrons, which we use to deduce the Martian magnetic topology and connectivity to the dayside ionosphere. Magnetic topology in the Mars environment is mapped in three dimensions for the first time. At low altitudes (<400 km) in sunlight, the northern hemisphere is found to be dominated by closed field lines (both ends intersecting the collisional atmosphere), with more day‐night connections through cross‐terminator closed field lines than in the south. Although draped field lines with ~100 km amplitude vertical fluctuations that intersect the electron exobase (~160–220 km) in two locations could appear to be closed at the spacecraft, a more likely explanation is provided by crustal magnetic fields, which naturally have the required geometry. Around 30% of the time, we observe open field lines from 200 to 400 km, which implies three distinct topological layers over the northern hemisphere: closed field lines below 200 km, open field lines with foot points at lower latitudes that pass over the northern hemisphere from 200 to 400 km, and draped interplanetary magnetic field above 400 km. This study also identifies open field lines with one end attached to the dayside ionosphere and the other end connected with the solar wind, providing a path for ion outflow.Key PointsPitch angle‐resolved electron energy shape parameters are used to deduce magnetic topologyClosed magnetic field lines dominate low altitudes (<400 km) of the northern hemisphere on the daysideThe 3‐D view of the Martian magnetic topology is presented for the first timePeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136484/1/jgra53291.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136484/2/jgra53291_am.pd

    An Australian longitudinal pilot study examining health determinants of cardiac outcomes 12 months post percutaneous coronary intervention

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    Background Percutaneous coronary intervention (PCI) is a very common revascularisation procedure for coronary artery disease (CAD). The purpose of this study was to evaluate cardiac outcomes, health related quality of life (HRQoL), resilience and adherence behaviours in patients who have undergone a PCI at two time points (6 and 12 months) following their procedure. Methods A longitudinal pilot study was conducted to observe the cardiac outcomes across a cohort of patients who had undergone a percutaneous coronary intervention (PCI). Participants who had undergone PCI 6 months prior were invited. Those participants who met the inclusion criteria and provided consent then completed a telephone survey (time point 1). These participants were then contacted 6 months later (i.e. 12 months post-intervention, time point 2) and the measures were repeated. Results All patients (n = 51) were recorded as being alive at time point 1. The multiple model indicated that controlling for other factors, gender was significantly associated with a linear combination of outcome measures (p = 0.004). The effect was moderate in magnitude (partial-η2 = 0.303), where males performed significantly better than females 6 months after the PCI procedure physically and with mood. Follow-up univariate ANOVAs indicated that gender differences were grounded in the scale measuring depression (PHQ9) (p = 0.005) and the physical component score of the short form measuring HRQoL (SF12-PCS) (p = 0.003). Thirteen patients were lost to follow-up between time points 1 and 2. One patient was confirmed to have passed away. The pattern of correlations between outcome measures at time point 2 revealed statistically significant negative correlation between the PHQ instrument and the resilience scale (CD-RISC) (r = -0.611; p < 0.001); and the physical component score of the SF-12 instrument (r = -0.437; p = 0.054). Conclusions Men were performing better than women in the 6 months post-PCI, particularly in the areas of mood (depression) and physical health. This pilot results indicate gender-sensitive practices are recommended particularly up to 6 months post-PCI. Any gender differences observed at 6 month appear to disappear at 12 months post-PCI. Further research into the management of mood particularly for women post-PCI is warranted. A more detailed inquiry related to access/attendance to secondary prevention is also warranted

    Effects of Thyroxine Exposure on Osteogenesis in Mouse Calvarial Pre-Osteoblasts

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    The incidence of craniosynostosis is one in every 1,800-2500 births. The gene-environment model proposes that if a genetic predisposition is coupled with environmental exposures, the effects can be multiplicative resulting in severely abnormal phenotypes. At present, very little is known about the role of gene-environment interactions in modulating craniosynostosis phenotypes, but prior evidence suggests a role for endocrine factors. Here we provide a report of the effects of thyroid hormone exposure on murine calvaria cells. Murine derived calvaria cells were exposed to critical doses of pharmaceutical thyroxine and analyzed after 3 and 7 days of treatment. Endpoint assays were designed to determine the effects of the hormone exposure on markers of osteogenesis and included, proliferation assay, quantitative ALP activity assay, targeted qPCR for mRNA expression of Runx2, Alp, Ocn, and Twist1, genechip array for 28,853 targets, and targeted osteogenic microarray with qPCR confirmations. Exposure to thyroxine stimulated the cells to express ALP in a dose dependent manner. There were no patterns of difference observed for proliferation. Targeted RNA expression data confirmed expression increases for Alp and Ocn at 7 days in culture. The genechip array suggests substantive expression differences for 46 gene targets and the targeted osteogenesis microarray indicated 23 targets with substantive differences. 11 gene targets were chosen for qPCR confirmation because of their known association with bone or craniosynostosis (Col2a1, Dmp1, Fgf1, 2, Igf1, Mmp9, Phex, Tnf, Htra1, Por, and Dcn). We confirmed substantive increases in mRNA for Phex, FGF1, 2, Tnf, Dmp1, Htra1, Por, Igf1 and Mmp9, and substantive decreases for Dcn. It appears thyroid hormone may exert its effects through increasing osteogenesis. Targets isolated suggest a possible interaction for those gene products associated with calvarial suture growth and homeostasis as well as craniosynostosis. © 2013 Cray et al

    JIRAM/Juno limb observations of H3+ in the mid- and low latitude Jovian atmosphere

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    NASA's Juno mission has been investigating Jupiter since August 2016, providing unprecedented insights into the giant planet's atmosphere. The Jupiter Infrared Auroral Mapper (JIRAM) experiment, on board Juno, performed spectroscopic observations of the H3+ emissions in both auroral regions (Dinelli et al., 2017; Adriani et al., 2017; Mura et al., 2017) and at mid-latitudes. In this work we analyse observations acquired over five orbits by the JIRAM spectrometer during the period from August 2016 to March 2017. In particular, during these observations, the spectrometer slit sampled Jupiter's limb over latitudes ranging from 60∘ equatorward, in both hemispheres. Limb spectra show typical H3+ emission features in the 3-4 μm spectral band, used to retrieve the H3+ densities and temperatures. Spatial resolution of the limb observations ranges between 50 and 130 km and is favourable for investigating the vertical distribution of H3+. Vertical profiles of H3+ limb intensities, in the 3-4 μm spectral band, are presented along with preliminary retrievals of the vertical profiles of H3+ volume mixing ratio (VMR). We compare our results with predictions from various atmospheric models. Acknowledgments The project JIRAM is funded by the Italian Space Agency

    土星の環から大気に雨が降っている

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    Magnetic reconnection signature in Jupiter's H3(+) auroral activity

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    Modelling the Io Plasma Torus and Application to the Variability of the Io Footprint Position observed by Juno-JIRAM

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    Jupiter hosts very intense auroral emissions, which originates from various magnetospheric processes. One of these emissions is associated with the orbital motion of the innermost Galilean satellite Io, which orbits at ~5.9 RJ (1 RJ = 71492km). At that distance, the magnetospheric plasma is forced to corotation by the strong planetary magnetic field. Therefore Io, which orbits at a slower speed than the corotating plasma, is continuously swept by both the plasma and the Jovian magnetic field. The relative velocity between Io and the plasma triggers a perturbation that propagates along the magnetic field lines and towards the ionosphere as Alfvén waves. Along their way, the Alfvén waves can accelerate electrons into the planetary atmosphere, where they ultimately generate an auroral emission called the Io footprint. The position of the Io footprint depends on the speed of the Alfvén waves, which in turn depends on the magnetic field geometry and magnitude as well as on the plasma mass distribution around Io, whose sulfur-dioxide-rich atmosphere constantly supply a dense cloud of plasma around Jupiter, called the Io Plasma. In 2016, Juno reached the Jupiter system and, since then, the Jovian InfraRed Auroral Mapper (JIRAM) has been observing the infrared emission associated with the Io footprint with a spatial resolution of ~ few tens of km/pixel. Thanks to the high resolutions of JIRAM, we report evidences of variability in the Io footprint position that are not related to the System III (i.e: the frame corotating with Jupiter) longitude of Io. Using a model for the plasma distribution of the Io Plasma Torus and the magnetic field, we quantitatively determine the state of the plasma distribution corresponding the JIRAM observations. This is the first attempt to retrieve quantitative information on the torus variability by using the Io footprint position. The best-fit plasma density and temperature are consistent with previous observations and analysis of the Io Plasma Torus from the Voyager 1& Voyager 2; Cassini, Galileo and Hisaki spacecraft. Besides, we found that both density and temperature can exhibit remarkable non-System III variability, which can be ascribed either to local time asymmetry of the plasma in the Io torus or to temporal variation in the torus mass loading
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