Small scale magnetic structure in the induced Martian ionosphere and lower magnetic pile-up region

The data is in the form of an Excel file and contains data used for many of the figures in the 2022 J. Geophys. Res. paper at https://doi.org/10.1029/2021JA030139. The data included in this KU archive is meant to be supplemental.Small-scale magnetic structures have been observed in the induced Martian ionosphere by magnetometers onboard the Mars Global Surveyor (MGS) and the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. The origin and evolution of these structures remain poorly understood and the goal of the current paper is to better characterize them and their distribution in the dayside ionosphere using MAVEN data. MAVEN Langmuir probe data is used to find thermal pressures in the ionosphere. The structures studied range in size from about 20 km up to a couple of hundred km. We constrain our investigation to the northern hemisphere, dayside Martian ionosphere in order to minimize crustal magnetic field interference. Magnetic pressure spikes (and/or field component variations), along with thermal pressure behavior can also sometimes characterize small-scale structures. Minimum variance analyses (MVA) are carried out for each structure in order to help classify them (e.g., horizontal slabs, ionopause-like structures, flux tube and flux ropes). A “statistical” catalog of properties (pressure, field amplitude, ellipticity, width, etc.) is generated for about 1000 structures. One conclusion we reached from this survey is that slab-like features are more likely to be found than rope-like features for altitudes above 250 km. Paper published in J. Geophys. Res. ,2022NASA MAVE

Low Electron Temperatures Observed at Mars by MAVEN on Dayside Crustal Magnetic Field Lines

An edited version of this paper was published by AGU. Copyright 2019 American Geophysical Union.The ionospheric electron temperature is important for determining the neutral/photochemical escape rate from the Martian atmosphere via the dissociative recombination of O2+. The Langmuir Probe and Waves instrument onboard MAVEN (Mars Atmosphere and Volatile EvolutioN) measures electron temperatures in the ionosphere. The current paper studies electron temperatures in the dayside for two regions where (1) crustal magnetic fields are dominant and (2) draped magnetic fields are dominant. Overall, the electron temperature is lower in the crustal‐field regions, namely, the strong magnetic field region, which is due to a transport of cold electrons along magnetic field lines from the lower to upper atmosphere. The electron temperature is also greater for high solar extreme ultraviolet conditions, which is associated with the local extreme ultraviolet energy deposition. The current models underestimate the electron temperature above 250‐km altitude in the crustal‐field region. Electron heat conduction associated with a photoelectron transport in the crustal‐field regions is altered due to kinetic effects, such the magnetic mirror and/or ambipolar electric field because the electron mean free path exceeds the relevant length scale for electron temperature. The mirror force can affect the electron and heat transport between low altitudes, where the neutral density and related electron cooling rates are the greatest, and high altitudes, while the ambipolar electric field decelerates the electron's upward motion. These effects have not been included in current models of the electron energetics, and consideration of such effects on the electron temperature in the crustal‐field region should be considered for future numerical simulations

3-D extent of the main ionospheric trough - a case study

The EISCAT radar system has been used for the first time in a four-beam meridional mode. The FAST satellite and ALIS imaging system is used in conjunction to support the radar data, which was used to identify a main ionospheric trough. With this large latitude coverage the trough was passed in 21/2hours period. Its 3-dimensional structure is investigated and discussed. It is found that the shape is curved along the auroral oval, and that the trough is wider closer to the midnight sector. The position of the trough coincide rather well with various statistical models and this trough is found to be a typical one

Chemical composition, larvicidal and cytotoxic activity of Annona salzmannii (Annonaceae) seed oil

The seed oil of Annona salzmannii A. DC. was analyzed by GC-MS and 1 H qNMR, revealing a mixture of unsaturated (80.5%) and saturated (18.7%) fatty acids. Linoleic (45.3%) and oleic (33.5%) acid were the major unsaturated fatty acids identified, while palmitic acid (14.3%) was the major saturated fatty acid. The larvicidal effects of A. salzmannii seed oil were evaluated against third-instar larvae of Aedes aegypti (Linn.). The oil exhibited moderate larvicidal activity, with aLC50 of 569.77 ppm (95% CI = 408.11 to 825.88 ppm). However, when the cytotoxic effects of the oil were evaluated, no expressive antiproliferative effects were observed in tumor cell lines B16-F10 (mouse melanoma), HepG2 (human hepatocellular carcinoma), K562 (human chronic myelocytic leukemia), HL-60 (human promyelocytic leukemia), and non-tumor cell line PBMC (peripheral blood mononuclear cells), with IC50 values > 50 μg·mL-1. This is the first study to evaluate the chemical composition, larvicidal and cytotoxic activity of A. salzmannii seed oil

Association between maternal depression and anxiety episodes and rates of childhood injuries: a cohort study from England

Background: Maternal depression is common and associated with several child health outcomes. The impact on childhood injuries is underexplored, with existing studies relying on maternal reporting of injury occurrences. Using population healthcare databases from England, we assessed the association between maternal depression and/or anxiety episodes and rates of child poisonings, fractures, burns and serious injuries. Methods: We conducted a prospective cohort study of 207,048 mother-child pairs with linked primary care and hospitalisation data from the Clinical Practice Research Datalink and Hospital Episode Statistics, 1998-2013. Episodes of maternal depression and/or anxiety were identified using diagnoses, prescriptions and hospitalisations, with the child’s follow-up time divided into exposed and unexposed periods. Adjusted incidence rate ratios (aIRR) for child injury during maternal mental health episodes were estimated using Poisson regression. Results: 54,702 children (26.4%) were exposed to maternal depression and/or anxiety when aged 0-4 years. During follow-up 2,614 poisonings, 6,088 fractures and 4,201 burns occurred. Child poisoning rates increased during episodes of maternal depression (aIRR 1.52, 95% confidence interval 1.31-1.76), depression with anxiety (2.30, 1.93-2.75) and anxiety alone (1.63, 1.09-2.43). Similarly, rates of burns (1.53, 1.29-1.81) and fractures (1.24, 1.06-1.44) were greatest during depression with anxiety episodes. There was no association between maternal depression and/or anxiety and serious child injuries. Conclusions: Maternal depression and/or anxiety episodes were associated with increased rates of child poisonings, fractures and burns. Whilst mechanisms are unclear, prompt identification and treatment of maternal depression and/or anxiety and provision of safety advice (e.g. safe medication storage) may reduce child injury risk

Observations and Modeling of the Mars Low‐Altitude Ionospheric Response to the 10 September 2017 X‐Class Solar Flare

Solar extreme ultraviolet and X‐ray photons are the main sources of ionization in the Martian ionosphere and can be enhanced significantly during a solar flare. On 10 September 2017, the Mars Atmosphere and Volatile EvolutioN orbiter observed an X8.2 solar flare, the largest it has encountered to date. Here we investigate the ionospheric response before, during, and after this event with the SuperThermal Electron Transport model. We find good agreement between modeled and measured photoelectron spectra. In addition, the high photoelectron fluxes during the flare provide adequate statistics to allow us to clearly and repeatedly identify the carbon Auger peak in the ionospheric photoelectron energy spectra at Mars for the first time. By applying photochemical equilibrium, O2+ and CO2+ densities are obtained and compared with Mars Atmosphere and Volatile EvolutioN observations. The variations in ion densities during this event due to the solar irradiance enhancement and the neutral atmosphere expansion are discussed.Plain Language SummarySolar extreme ultraviolet and X‐ray photons are the main source of ionization in the Martian ionosphere, photoionizing the neutral particles and producing photoelectrons and ions. These short‐wavelength photon fluxes can be enhanced by a factor of a few to orders of magnitudes during a solar flare (the result of the rapid conversion of magnetic energy to kinetic energy in the solar corona). On 10 September 2017, the Mars Atmosphere and Volatile EvolutioN mission encountered the largest solar flare (X8.2) to date. The comprehensive measurements from Mars Atmosphere and Volatile EvolutioN provide us with an opportunity to evaluate the ionospheric response to this flare event in detail with models. In particular, we investigate the photoelectron flux and ion density response to the flare with an electron transport model. The modeled and measured photoelectron fluxes are in a good agreement. Ion density enhancement at a fixed altitude is from tens of percent to 1500% due to a combination of intensified solar photon fluxes and the heated and then expanded neutral atmosphere during this flare event.Key PointsThe modeled and measured photoelectron spectra are in good agreement during an X8.2 solar flare eventThe carbon Auger peak is clearly and repeatedly identified in electron energy spectra of the Martian ionosphere for the first timeThe ion density enhancement due to the flare at a fixed altitude is from tens to 1,500%Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145576/1/grl57692.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145576/2/grl57692_am.pd