In this study we present AI Prediction of Equatorial Plasma Bubbles (APE), a machine learning model that can accurately predict the Ionospheric Bubble Index (IBI) on the Swarm spacecraft. IBI is a ...correlation (R2) between perturbations in plasma density and the magnetic field, whose source can be Equatorial Plasma Bubbles (EPBs). EPBs have been studied for a number of years, but their day‐to‐day variability has made predicting them a considerable challenge. We build an ensemble machine learning model to predict IBI. We use data from 2014 to 2022 at a resolution of 1s, and transform it from a time‐series into a 6‐dimensional space with a corresponding EPB R2 (0–1) acting as the label. APE performs well across all metrics, exhibiting a skill, association and root mean squared error score of 0.96, 0.98 and 0.08 respectively. The model performs best post‐sunset, in the American/Atlantic sector, around the equinoxes, and when solar activity is high. This is promising because EPBs are most likely to occur during these periods. Shapley values reveal that F10.7 is the most important feature in driving the predictions, whereas latitude is the least. The analysis also examines the relationship between the features, which reveals new insights into EPB climatology. Finally, the selection of the features means that APE could be expanded to forecasting EPBs following additional investigations into their onset.
Key Points
AI Prediction of EPBs (APE) can accurately predict the Swarm Ionospheric Bubble Index
APE is an XGBoost regressor that outperforms similarly trained linear and random forest models
Game theory techniques reveals the influence of solar and geomagnetic activity as well as geo‐location, time, and season
Aims/hypothesis Studies have shown a relationship between pre-eclampsia and later coronary artery disease. This study investigated whether there is a relationship between pre-eclampsia and the ...development of type 2 diabetes in mothers and their babies and how this is affected by infant birthweight. Subjects and methods This was an intergenerational cohort study. The study population comprised 7,187 mothers who gave birth and 8,648 babies who were born in Dundee, Scotland between 1952 and 1958. Their later diabetic status was defined from 1980 to 2003 by linkage to population-based datasets. Results There were 810 (11.3%) mothers with pre-eclampsia and 745 (10.4%) who subsequently developed type 2 diabetes. Logistic regression showed an increased risk of developing type 2 diabetes for mothers with pre-eclampsia, unadjusted odds ratio (OR) 1.37 (95% CI 1.10-1.71), p = 0.005. This relationship persisted after adjustment for infant birthweight, OR 1.40 (95% CI 1.12-1.75), p = 0.003. Of the babies born between 1952 and 1958, 221 (2.6%) had developed type 2 diabetes, 137 of them male (2.9% of male subjects in study population) and 84 female (2.2% of female subjects). The relationship between pre-eclampsia in the mother and the risk of type 2 diabetes in the offspring did not reach statistical significance, OR 1.38 (95% CI 0.90-2.10). Babies with birthweight in the lowest quintile (adjusted for sex, gestation and birth order) had an increased risk of developing type 2 diabetes, OR for lowest quintile vs highest quintile 1.84 (95% CI 1.24-2.72), p = 0.002. Conclusions/interpretation Pre-eclampsia is associated with increased risk of developing type 2 diabetes in the mother, but birthweight is a more important determinant of future risk for the offspring.
Visible to neutrons: Although thought to be involved in biological processes, hydronium ions had never been identified in biomacromolecular crystallographic structures. A hydronium ion has now been ...found by neutron and X‐ray crystallography to interchange with metal cofactors in the active site of an enzyme. Under more acidic conditions, the hydronium ion is dehydrated to a proton, and the binding site collapses (see picture).
Archetypal O-acetylation reactions of alcohols and carbohydrates proceed rapidly in high yield under mild conditions in a dicyanamide based ionic liquid, that is not only an effective solvent but ...also an active base catalyst.
This randomized clinical trial evaluated an HIV-risk
reduction (HIV-RR) intervention based on the
information-motivation-behavioral skills model. At
baseline, 102 women (
M
age = 29 years; 88% ...African
American) completed a survey regarding HIV-related knowledge, risk
perceptions, behavioral intentions, and risk behavior. Participants
were then assigned to either the HIV-RR intervention or a
health-promotion control group. Postintervention and follow-up data
indicated that women in the HIV-RR program enhanced their knowledge
and strengthened their risk reduction intentions relative to
controls. Moreover, HIV-RR women who expressed "imperfect"
intentions also increased their condom use, talked more with
partners about condom use and HIV testing, and were more likely to
have refused unprotected sex.
This research evaluated a motivation-based HIV risk reduction intervention for economically disadvantaged urban women. Participants completed a survey that assessed HIV-related knowledge, risk ...perceptions, behavioral intentions, sexual communication, substance use, and risk behavior. A total of 102 at-risk women (76% African American) were randomly assigned to either the risk reduction intervention or to a waiting list. Women were reassessed at 3 and 12 weeks. Results indicated that treated women increased their knowledge and risk awareness, strengthened their intentions to adopt safer sexual practices, communicated their intentions with partners, reduced substance use proximal to sexual activities, and engaged in fewer acts of unprotected vaginal intercourse. These effects were observed immediately, and most were maintained at follow-up.
The high energy electron population in Earth's outer radiation belt is extremely variable, changing by multiple orders of magnitude on timescales that vary from under an hour to several weeks. These ...changes are typically linked to geomagnetic activity such as storms and substorms. In this study, we seek to understand how coherent changes in the radiation belt are across all radial distances, in order to provide a spatial insight into apparent global variations. We do this by calculating the correlation between fluxes on different L* measured by the PET instrument aboard the SAMPEX spacecraft for times associated with 15 large storms. Our results show that during these times, variations in the >0.63 MeV electron flux are coherent outside the minimum plasmapause location and also coherent inside the minimum plasmapause location, when flux is present. However, variations in the electron fluxes inside the plasmapause show little correlation with those outside the plasmapause. During storm recovery and possibly main phases, flux variations are coherent across all L* regardless of plasmapause location, due to a rapid decrease, followed by an increase in radiation belt fluxes across all L*.
Key Points
Near‐relativistic electron fluxes associated with storms are highly correlated (r2>0.8) cross‐L* outside the minimum plasmapause location
Electron fluxes inside the minimum location of the plasmapause are also well correlated but show little correlation with fluxes outside
During storm main and recovery phases, the electron fluxes are well correlated across all L* irrespective of the plasmapause location
Sodium-based batteries have emerged as promising alternatives to Li-based batteries for future safe, high energy-density energy storage. They are expected to be cheaper, due to the greater abundance ...of Na and likely reduction in raw material costs. In this study, we investigate the properties of superconcentrated sodium bis(fluorosulfonyl)amide (NaFSI) mixtures with the ionic liquid (IL) methylpropylpyrrolinium (C3mpyr) FSI in the presence of ethylene carbonate (EC) in the liquid and gel states. Ionic conductivity and thermal stability are evaluated through electrochemical impedance spectroscopy (EIS) and differential scanning calorimetry (DSC), respectively. NaFSI is soluble in the IL up to 55 mol% Na; adding EC (30wt.%) to the IL almost doubles the ionic conductivity at ambient temperature. The temperature dependence of conductivity is well described by the Vogel-Tamman-Fulcher equation. NMR spectroscopy and Pulse Field Gradient NMR diffusion were employed to investigate transport in these electrolyte systems, while the chemical interactions were also studied using ATR-FTIR. Stable plasticized gel electrolytes were observed, even at 30wt. % EC; the formation of the gel does not significantly affect the liquid-like ion dynamics in these materials, as shown by DSC and FTIR analysis. The Na+ transference number of Na0.55C3mpyr0.45FSI+30wt.% EC was up to 0.32, and deposition and dissolution of sodium metal were observed in cyclic voltammetry around 0V vs. Na/Na+. Moreover, the suitability of the prepared electrolyte is preliminarily verified in half-cells at room temperature using Na3V2(PO4)3 as a cathode. The cells delivered capacity of 52.4 mAhg−1 at C/20.
Finite element (FE) modelling has a role to play in simulating elastic wave propagation associated with structural vibrations, acoustic phenomena and ultrasound problems. In this work we have used ...the PAFEC software PAFEC finite element software PACSYS, Strelley Hall, Nottingham, NG8 6PE, UK.
With the advent of increased computer power and greater availability of software these simulations have become more readily available and will provide improved insight into wave propagation problems. Simulations have been undertaken of transient wave propagation in steel plates with an attached simple resonant transducer. This simulates acoustic emission (AE) propagation in plate like structures relevant to many industrial applications.
Simulations for short propagation distances suggest the resonant transducer voltage signal carries information on the plate-waves propagating in the structure, overlaid with the piezoelectric resonance and some information might be extracted from the transducer signal.
Looking at the wave propagation information alone, a great deal of variability is seen in the displacement profile for different source types, orientations and locations. Although users have expressed a need for calibration of the AE detection process, this idea remains problematic since the complete generation and detection system has the features of a chaotic system.
Using FE modelling a method of “point calibration” might be available, for some specific AE applications such as crack growth along known paths.
The electrochemical reduction of tetrabutylammonium salts of isostructural pairs of polyoxometalates Bu4N2M6O19, Bu4N4α-SiM12O40, and Bu4N4α-S2M18O62 (M = Mo or W) has been investigated at glassy ...carbon electrodes in dissolved and surface-confined states in ionic liquids and other media. In the ionic liquid 1-n-butyl-3-methylimidazolium hexafluorophosphate BMIMPF6, between two and six reversible one-electron-transfer processes were detected. Detailed studies on the process α-S2W18O624-/5- in a range of ionic liquids, water, and conventional organic solvents (containing 0.1 M electrolyte) suggest that the polarity of the medium plays a key role in the determination of the reversible potential. Reduction processes involving very highly charged α-S2W18O628-/9-/10- species are strongly influenced by the purity of the medium.
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