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Automatically adaptive grid resolution is a common way of improving simulation accuracy while keeping computational efficiency at a manageable level. In space physics, adaptive grid strategies are especially useful as simulation volumes are extreme, while the most accurate physical description is based on electron dynamics and hence requires very small grid cells and time steps. Therefore, many past global simulations encompassing, for example, near-Earth space have made tradeoffs in terms of the physical description and laws of magnetohydrodynamics (MHD) used that require less accurate grid resolutions. Recently, using supercomputers, it has become possible to model the near-Earth space domain with an ion-kinetic hybrid scheme going beyond MHD-based fluid dynamics. These simulations, however, must develop a new adaptive mesh strategy beyond what is used in MHD simulations. We developed an automatically adaptive grid refinement strategy for ion-kinetic hybrid-Vlasov schemes, and we implemented it within the Vlasiator global solar wind–magnetosphere–ionosphere simulation. This method automatically adapts the resolution of the Vlasiator grid using two indices: one formed as a maximum of dimensionless gradients measuring the rate of spatial change in selected variables and the other derived from the ratio of the current density to the magnetic field density perpendicular to the current. Both these indices can be tuned independently to reach a desired level of refinement and computational load. We test the indices independently and compare the results to a control run using static refinement. The results show that adaptive refinement highlights relevant regions of the simulation domain and keeps the computational effort at a manageable level. We find that the refinement shows some overhead in the rate of cells solved per second. This overhead can be large compared to the control run without adaptive refinement, possibly due to resource utilization, grid complexity, and issues in load balancing. These issues lay out a development roadmap for future optimizations.

Introduction Gestational diabetes mellitus (GDM) is one of the most common medical complications of pregnancy. Glycaemic control decreases the risk of adverse pregnancy outcomes for the affected pregnant individual and the infant exposed in utero. One in four individuals with GDM will require pharmacotherapy to achieve glycaemic control. Injectable insulin has been the mainstay of pharmacotherapy. Oral metformin is an alternative option increasingly used in clinical practice. Both insulin and metformin reduce the risk of adverse pregnancy outcomes, but comparative effectiveness data from a well-characterised, adequately powered study of a diverse US population remain lacking. Because metformin crosses the placenta, long-term safety data, in particular, the risk of childhood obesity, from exposed children are also needed. In addition, the patient-reported experiences of individuals with GDM requiring pharmacotherapy remain to be characterised, including barriers to and facilitators of metformin versus insulin use.Methods and analysis In a two-arm open-label, pragmatic comparative effectiveness randomised controlled trial, we will determine if metformin is not inferior to insulin in reducing adverse pregnancy outcomes, is comparably safe for exposed individuals and children, and if patient-reported factors, including facilitators of and barriers to use, differ between metformin and insulin. We plan to recruit 1572 pregnant individuals with GDM who need pharmacotherapy at 20 US sites using consistent diagnostic and treatment criteria for oral metformin versus injectable insulin and follow them and their children through delivery to 2 years post partum. More information is available at www.decidestudy.org.Ethics and dissemination The Institutional Review Board at The Ohio State University approved this study (IRB: 2024H0193; date: 7 December 2024). We plan to submit manuscripts describing the results of each study aim, including the pregnancy outcomes, the 2-year follow-up outcomes, and mixed-methods assessment of patient experiences for publication in peer-reviewed journals and presentations at international scientific meetings.Trial registration number NCT06445946.

Magnetic reconnection is a crucially important process for energy conversion in plasma physics, with the substorm cycle of Earth's magnetosphere and solar flares being prime examples. While 2D models have been widely applied to study reconnection, investigating reconnection in 3D is still, in many aspects, an open problem. Finding sites of magnetic reconnection in a 3D setting is not a trivial task, with several approaches, from topological skeletons to Lorentz transformations, having been proposed to tackle the issue. This work presents a complementary method for quasi-2D structures in 3D settings by noting that the magnetic field structures near reconnection lines exhibit 2D features that can be identified in a suitably chosen local coordinate system. We present applications of this method to a hybrid-Vlasov Vlasiator simulation of Earth's magnetosphere, showing the complex magnetic topologies created by reconnection for simulations dominated by quasi-2D reconnection. We also quantify the dimensionalities of magnetic field structures in the simulation to justify the use of such coordinate systems.

Scientific computing has become increasingly parallel and heterogeneous with the proliferation of graphics processing unit (GPU) use in data centers, allowing for thousands of simultaneous calculations accessing high-bandwidth memory. Adoption of these resources may require re-design of scientific software. Hashmaps are a widely used data structure linking unsorted unique keys with values for fast data retrieval and storage. Several parallel libraries exist for performing hashmap operations utilizing GPU hardware, but none have yet supported GPUs and CPUs interchangeably. We introduce Hashinator, a novel portable hashmap designed to operate efficiently on both CPUs and GPUs using CUDA or HIP/ROCm Unified Memory, offering host access methods, in-kernel access methods, and efficient GPU offloading capability on both NVIDIA and AMD hardware. Hashinator utilizes open addressing with Fibonacci hashing and power-of-two capacity. By comparing against existing implementations, we showcase the excellent performance and flexibility of Hashinator, making it easier to port scientific codes that rely heavily on the use of hashmaps to heterogeneous architectures.

Solar wind charge exchange produces emissions in the soft X-ray energy range which can enable the study of near-Earth space regions such as the magnetopause, the magnetosheath and the polar cusps by remote sensing techniques. The Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) and Lunar Environment heliospheric X-ray Imager (LEXI) missions aim to obtain soft X-ray images of near-Earth space thanks to their Soft X-ray Imager (SXI) instruments. While earlier modeling works have already simulated soft X-ray images as might be obtained by SMILE SXI during its mission, the numerical models used so far are all based on the magnetohydrodynamics description of the space plasma. To investigate the possible signatures of ion-kinetic-scale processes in soft X-ray images, we use for the first time a global hybrid-Vlasov simulation of the geospace from the Vlasiator model. The simulation is driven by fast and tenuous solar wind conditions and purely southward interplanetary magnetic field. We first produce global X-ray images of the dayside near-Earth space by placing a virtual imaging satellite at two different locations, providing meridional and equatorial views. We then analyze regional features present in the images and show that they correspond to signatures in soft X-ray emissions of mirror-mode wave structures in the magnetosheath and flux transfer events (FTEs) at the magnetopause. Our results suggest that, although the time scales associated with the motion of those transient phenomena will likely be significantly smaller than the integration time of the SMILE and LEXI imagers, mirror-mode structures and FTEs can cumulatively produce detectable signatures in the soft X-ray images. For instance, a local increase by 30% in the proton density at the dayside magnetopause resulting from the transit of multiple FTEs leads to a 12% enhancement in the line-of-sight- and time-integrated soft X-ray emissivity originating from this region. Likewise, a proton density increase by 14% in the magnetosheath associated with mirror-mode structures can result in an enhancement in the soft X-ray signal by 4%. These are likely conservative estimates, given that the solar wind conditions used in the Vlasiator run can be expected to generate weaker soft X-ray emissions than the more common denser solar wind. These results will contribute to the preparatory work for the SMILE and LEXI missions by providing the community with quantitative estimates of the effects of small-scale, transient phenomena occurring on the dayside.

Magnetosheath jets are plasma structures that are characterised by enhanced dynamic pressure and/or plasma velocity. In this study, we investigate the formation of magnetosheath jets in four two-dimensional simulation runs of the global magnetospheric hybrid-Vlasov model Vlasiator. We focus on jets whose origins were not clearly determined in a previous study using the same simulations (Suni et al., 2021) to have been associated with foreshock structures of enhanced dynamic pressure and magnetic field. We find that these jets can be divided into two categories based on their direction of propagation, either predominantly antisunward or predominantly toward the flanks of the magnetosphere. As antisunward-propagating jets can potentially impact the magnetopause and have effects on the magnetosphere, understanding which foreshock and bow shock phenomena are associated with them is important. The antisunward-propagating jets have properties indistinguishable from those of the jets found in the previous study. This indicates that the antisunward jets investigated in this paper belong to the same continuum as the jets previously found to be caused by foreshock structures; however, due to the criteria used in the previous study, they did not appear in this category before. These jets together make up 86 % of all jets in this study. The flankward-propagating jets make up 14 % of all jets and are different, showing no clear association with foreshock structures and exhibiting temperature anisotropy unlike the other jets. We suggest that they could consist of quasi-perpendicular magnetosheath plasma, indicating that these jets could be associated with local turning of the shock geometry from quasi-parallel to quasi-perpendicular. This turning could be due to bow shock reformation at the oblique shock caused by foreshock ultralow-frequency (ULF) wave activity.

Abstract Flux transfer events (FTEs) are transient magnetic flux ropes at Earth's dayside magnetopause formed due to magnetic reconnection. As they move across the magnetopause surface, they can generate disturbances in the ultralow frequency (ULF) range, which then propagate into the magnetosphere. This study provides evidence of ULF waves in the Pc2 wave frequency range (>0.1 Hz) caused by FTEs during dayside reconnection using a global 3D hybrid‐Vlasov simulation (Vlasiator). These waves resulted from FTE formation and propagation at the magnetopause are particularly associated with large, rapidly moving FTEs. The wave power is stronger in the morning than afternoon, showing local time asymmetry. In the pre and postnoon equatorial regions, significant poloidal and toroidal components are present alongside the compressional component. The noon sector, with fewer FTEs, has lower wave power and limited magnetospheric propagation.

Introduction The prevalence of both obesity and gestational diabetes mellitus (GDM) has increased, and each is associated with adverse perinatal outcomes including fetal overgrowth, neonatal morbidity, hypertensive disorders of pregnancy and caesarean delivery. Women with GDM who are also overweight or obese have higher rates of pregnancy complications when compared with normal-weight women with GDM, which may occur in part due to suboptimal glycaemic control. The current recommendations for glycaemic targets in pregnant women with diabetes are based on limited evidence and exceed the mean fasting (70.9±7.8 mg/dL) and 1-hour postprandial (108.9±12.9 mg/dL) glucose values in pregnant individuals without diabetes. Our prior work demonstrated that the use of intensive (fasting

Abstract Shocklets and short large‐amplitude magnetic structures (SLAMS) are steepened magnetic fluctuations commonly found in Earth's upstream foreshock. Here we present Venus Express observations from the 26th of February 2009 establishing their existence in the steady‐state foreshock of Venus, building on a past study which found SLAMS during a substantial disturbance of the induced magnetosphere. The Venusian structures were comparable to those reported near Earth. The 2 Shocklets had magnetic compression ratios of 1.23 and 1.34 with linear polarization in the spacecraft frame. The 3 SLAMS had ratios between 3.22 and 4.03, two of which with elliptical polarization in the spacecraft frame. Statistical analysis suggests SLAMS coincide with unusually high solar wind Alfvén mach‐number at Venus (12.5, this event). Thus, while we establish Shocklets and SLAMS can form in the stable Venusian foreshock, they may be rarer than at Earth. We estimate a lower limit of their occurrence rate of ≳14%.

All instances of the semidirect key exchange protocol, a generalisation of the famous Diffie-Hellman key exchange protocol, satisfy the so-called telescoping equality; in some cases, this equality has been used to construct an attack. In this report, we present computational evidence suggesting that an instance of the scheme called “MOBS (matrices over bitstrings)” is an example of a scheme where the telescoping equality has too many solutions to be a practically viable means to conduct an attack.

Numerical simulation models that are used to investigate the near-Earth space plasma environment require sophisticated methods and algorithms as well as high computational power. Vlasiator 5.0 is a hybrid-Vlasov plasma simulation code that is able to perform 6D (3D in ordinary space and 3D in velocity space) simulations using adaptive mesh refinement (AMR). In this work, we describe a side effect of using AMR in Vlasiator 5.0: the heterologous grid approach creates discontinuities due to the different grid resolution levels. These discontinuities cause spurious oscillations in the electromagnetic fields that alter the global results. We present and test a spatial filtering operator for alleviating this artifact without significantly increasing the computational overhead. We demonstrate the operator's use case in large 6D AMR simulations and evaluate its performance with different implementations.

Abstract Objective Obesity in pregnancy and gestational diabetes (GDM) increase cardiometabolic disease risk but are difficult to disentangle. This study aimed to test the hypothesis that 4–10 years after a pregnancy complicated by overweight/obesity and GDM (OB‐GDM), women and children would have greater adiposity and poorer cardiometabolic health than those with overweight/obesity (OB) or normal weight (NW) and no GDM during the index pregnancy. Methods In this cross‐sectional study, mother‐child dyads were stratified into three groups based on maternal health status during pregnancy (OB‐GDM = 67; OB = 76; NW = 76). Weight, height, waist and hip circumferences, and blood pressure were measured, along with fasting glucose, insulin, HbA1c, lipids, adipokines, and cytokines. Results Women in the OB and OB‐GDM groups had greater current adiposity and poorer cardiometabolic health outcomes than those in the NW group (p

The Kelvin–Helmholtz instability (KHI), characterized by vortices forming at a perturbed velocity shear layer, is a prominent candidate mechanism for mass, momentum, and energy transport across boundaries with velocity shear in various space plasma environments. It is of particular interest at the flanks of Earth’s magnetopause, which separates the plasma of the magnetosphere from the adjacent shocked solar wind flow in the magnetosheath. In the present study, we use local hybrid-Vlasov simulations to investigate the ion velocity distribution functions (VDFs) associated with KHI in a magnetopause-like, transverse velocity shear layer setting (magnetic field perpendicular to the shear plane). We look for signatures of ion finite Larmor radius (FLR) effects, which could be utilized in spacecraft measurements to recognize when such effects are active, influencing KHI evolution and driving plasma mixing. We show that when a density/temperature asymmetry exists across the shear layer, FLR effects produce a heat flux along the vortex edges. With a magnitude (≳0.1 mW m ^−2 ) that is a significant fraction of the total magnetosheath energy flux, the heat flux provides a distinct signature that could be measured with a single spacecraft. During the late nonlinear stage of KHI, mixed non-Maxwellian ion VDFs are additionally found within the vortices. Our results are also valid in the presence of a small magnetic shear across the magnetopause.

Abstract Aquatic invasive species, such as the signal crayfish (Pacifastacus leniusculus), present a major threat to freshwater ecosystems. However, these species can be challenging to detect in recently invaded habitats. Environmental DNA (eDNA)–based methods are highly sensitive and capable of detecting just a few copies of target DNA from non‐invasively collected samples. Therefore, they have considerable potential for broad‐scale use in mapping and monitoring the spread of invasive species. In this study, we aimed to increase our understanding of the current distribution of signal crayfish in a headwater stream system in the United Kingdom (tributaries of the River Wharfe, Addingham, Yorkshire). Environmental DNA sampling, assessment of water chemistry variables, and conventional crayfish hand‐searching were conducted across 19 study sites in five tributary streams. Using hand‐searching, we detected signal crayfish at 26% of the sites (5/19 study sites). However, using eDNA‐based methods, occupancy increased to 47% of study sites (9/19). Our sampling revealed previously unknown sites of crayfish occupancy, and using eDNA‐based methods, we were able to define the geographical extent of the invasion front in each headwater stream sampled. This study highlights that eDNA‐based methods are well‐suited for detecting newly established signal crayfish populations in recently invaded habitats, even when the invasive species is at low abundance and, therefore, might otherwise be under‐represented or undetected using conventional survey methods. Our study provides further evidence that headwater stream ecosystems are particularly vulnerable to signal crayfish invasion. However, their geomorphological features may make methods used to reduce or prevent invasive crayfish dispersal more effective than in other freshwater ecosystems.

OBJECTIVE: To estimate the association between maternal metformin use for the treatment of early gestational or pre-existing type 2 diabetes and preterm preeclampsia. METHODS: This is a planned secondary analysis of the MOMPOD study (Medical Optimization of Management of Overt Type 2 Diabetes in Pregnancy), a randomized trial comparing the effect of adding metformin with insulin treatment on composite neonatal outcome in singleton pregnancies with early gestational or type 2 diabetes. Participants were randomized at 11-23 weeks of gestation to 1,000 mg metformin twice daily or placebo until delivery. A subset of participants had maternal blood collected at 24-30 weeks of gestation, and serum soluble endoglin, apolipoprotein B, vascular cell adhesion molecule-1, soluble fms-like tyrosine kinase 1, placental growth factor, high-sensitivity C-reactive protein, adiponectin, and vascular endothelial growth factor levels were measured. Our primary outcome was preterm preeclampsia, defined as preeclampsia requiring delivery before 37 weeks of gestation. Secondary outcomes included preterm preeclampsia requiring delivery before 34 weeks of gestation and differences in serum biomarkers. Multivariable regression analysis was used to estimate the associations between metformin use and primary or secondary study outcomes. RESULTS: Of 831 participants, 119 (14.3%) developed preeclampsia requiring delivery before 37 weeks of gestation: 57 of 416 (13.7%) in the placebo group and 62 of 415 (14.9%) in the metformin group. Thirty-seven (4.4%) developed preeclampsia requiring delivery before 34 weeks of gestation: 15 (3.6%) receiving placebo and 22 (5.3%) receiving metformin. Compared with placebo, metformin was not associated with a significant difference in the occurrence of preeclampsia before 37 weeks of gestation (adjusted odds ratio [aOR] 1.04, 95% CI, 0.70-1.56) or before 34 weeks (aOR 1.43, 95% CI, 0.73-2.81). Similarly, there was no association between maternal metformin use and serum biomarker levels. CONCLUSION: Among parturients with early gestational or pre-existing type 2 diabetes, the addition of metformin to insulin was not associated with lower odds of preterm preeclampsia or with serum biomarkers associated with cardiovascular disease risk. [ABSTRACT FROM AUTHOR]

Continuous glucose monitoring (CGM) has the potential to revolutionize diabetes management during pregnancy by providing detailed and real-time data to patients and clinicians, overcoming many of the limitations of selfmonitoring of blood glucose. Although there are limited data on the role of CGM to improve pregnancy outcomes in patients with type 2 diabetes or gestational diabetes, CGM has been shown to reduce pregnancy complications in patients with type 1 diabetes. Despite the limited data in some populations, given its ease of use and recent U.S. Food and Drug Administration approval with expanding insurance coverage, CGM has gained widespread popularity among pregnant patients with all types of diabetes. It is critical for obstetric clinicians to understand how CGM can be successfully integrated into clinical practice. We present a practical, step-wise approach to CGM data interpretation that can be incorporated into diabetes management during pregnancy and common CGM pitfalls and solutions. Although technology will continue to advance with newergeneration CGM devices and diabetes technology such as automated insulin delivery (not covered here), these key principles form a basic foundation for understanding CGM technology and its utility for pregnant people. [ABSTRACT FROM AUTHOR]

Objective Studies have suggested an association between prenatal care (PNC) and preterm birth (PTB). We evaluated trends in PTB and association of PNC and PTB. Study Design This was a retrospective cohort study of singleton, viable nonanomalous deliveries from 1991 to 2018. PNC utilization was defined by World Health Organization using number of visits: adequate (≥8), suboptimal (5–7), and inadequate (<5). Primary outcome was PTB. Tests of trend were used to assess changes in PTB over time. Baseline characteristics and outcomes were compared. Logistic regression estimated the association of PNC and PTB. We evaluated for effect modification by year of birth. Results Of 92,294 patients, 14,057 (15%) had PTB. Inadequate and suboptimal PNC were associated with higher odds of PTB compared to adequate PNC (adjusted odds ratios = [aOR 6.21], 95% confidence interval [CI]: 5.84–6.60; aOR = 3.57, 95% CI: 3.36–3.79). Inadequate PNC was associated with higher odds of PTB over time (effect modification p < 0.0001). Inadequate PNC was associated with 5.4 times higher odds of PTB in 1998, 7.0 times in 2008, and 9.1 times in 2018. Conclusion Despite an increase in adequate PNC, there was a rise in PTB associated with inadequate and suboptimal PNC. PNC utilization was a stronger risk factor in recent years with higher PTB in patients who attended more than five PNC visits. Key Points PNC utilization is associated with the risk of PTB. Despite an increase in PNC utilization, PTB rates have increased. There is an even stronger association between PNC utilization and PTB over time. [ABSTRACT FROM AUTHOR]

ABSTRACT: As the worldwide prevalence of overweight and obesity continues to rise, so too does the urgency to fully understand mediating mechanisms, to discover new targets for safe and effective therapeutic intervention, and to identify biomarkers to track obesity and the success of weight loss interventions. In 2016, the American Heart Association sought applications for a Strategically Focused Research Network (SFRN) on Obesity. In 2017, 4 centers were named, including Johns Hopkins University School of Medicine, New York University Grossman School of Medicine, University of Alabama at Birmingham, and Vanderbilt University Medical Center. These 4 centers were convened to study mechanisms and therapeutic targets in obesity, to train a talented cadre of American Heart Association SFRN‐designated fellows, and to initiate and sustain effective and enduring collaborations within the individual centers and throughout the SFRN networks. This review summarizes the central themes, major findings, successful training of highly motivated and productive fellows, and the innovative collaborations and studies forged through this SFRN on Obesity. Leveraging expertise in in vitro and cellular model assays, animal models, and humans, the work of these 4 centers has made a significant impact in the field of obesity, opening doors to important discoveries, and the identification of a future generation of obesity‐focused investigators and next‐step clinical trials. The creation of the SFRN on Obesity for these 4 centers is but the beginning of innovative science and, importantly, the birth of new collaborations and research partnerships to propel the field forward.

The foreshock located upstream of Earth's bow shock hosts a wide variety of phenomena related to the reflection of solar wind particles from the bow shock and the subsequent formation of ultra-low-frequency (ULF) waves. In this work, we investigate foreshock cavitons, which are transient structures resulting from the non-linear evolution of ULF waves, and spontaneous hot flow anomalies (SHFAs), which are thought to evolve from cavitons as they accumulate suprathermal ions while being carried to the bow shock by the solar wind. Using the global hybrid-Vlasov simulation model Vlasiator, we have conducted a statistical study in which we track the motion of individual cavitons and SHFAs in order to examine their properties and evolution. In our simulation run where the interplanetary magnetic field (IMF) is directed at a sunward–southward angle of 45∘, continuous formation of cavitons is found up to ∼11 Earth radii (RE) from the bow shock (along the IMF direction), and caviton-to-SHFA evolution takes place within ∼2 RE from the shock. A third of the cavitons in our run evolve into SHFAs, and we find a comparable amount of SHFAs forming independently near the bow shock. We compare the properties of cavitons and SHFAs to prior spacecraft observations and simulations, finding good agreement. We also investigate the variation of the properties as a function of position in the foreshock, showing that transients close to the bow shock are associated with larger depletions in the plasma density and magnetic field magnitude, along with larger increases in the plasma temperature and the level of bulk flow deflection. Our measurements of the propagation velocities of cavitons and SHFAs agree with earlier studies, showing that the transients propagate sunward in the solar wind rest frame. We show that SHFAs have a greater solar wind rest frame propagation speed than cavitons, which is related to an increase in the magnetosonic speed near the bow shock.

Ultra-low frequency (ULF) waves in the Pc3 range, with periods between 10–45 s, are routinely observed in Earth’s dayside magnetosphere. They are thought to originate in the foreshock, which extends upstream of the quasi-parallel bow shock and is populated with shock-reflected particles. The foreshock is permeated with ULF waves generated by ion beam instabilities, most notably the “30-s” waves whose periods match those of the Pc3 waves and which are carried earthward by the solar wind flow. However, the global picture of Pc3 wave activity from the foreshock to the magnetosphere and its response to changing solar wind conditions is still poorly understood. In this study, we investigate the global distribution and properties of Pc3 waves across near-Earth space using global simulations performed with the hybrid-Vlasov model Vlasiator. The simulations enable us to study the waves in their global context, and compare their properties in the foreshock, magnetosheath and dayside magnetosphere, for different sets of upstream solar wind conditions. We find that in all three regions the Pc3 wave power peaks at higher frequencies when the interplanetary magnetic field (IMF) strength is larger, consistent with previous studies. The Pc3 wave power is significantly enhanced in all three regions for higher solar wind Alfvén Mach number. As this parameter is known to affect the shock properties but has little impact inside the magnetosphere, this brings further support to the magnetospheric waves originating in the foreshock. Other parameters that are found to influence the foreshock wave power are the solar wind density and the IMF cone angle. Inside the magnetosphere, the wave power distribution depends strongly on the IMF orientation, which controls the foreshock position upstream of the bow shock. The wave power is largest when the angle between the IMF and the Sun-Earth line is smallest, suggesting that wave generation and transmission are most efficient in these conditions.

Ultra-low frequency (ULF) waves are routinely observed in Earth’s dayside magnetosphere. Here we investigate the influence of externally-driven density variations in the near-Earth space in the ULF regime using global 2D simulations performed with the hybrid-Vlasov model Vlasiator. With the new time-varying boundary setup, we introduce a monochromatic Pc5 range periodic density variation in the solar wind. A breathing motion of the magnetopause and changes in the bow shock standoff position are caused by the density variation, the time lag between which is found to be consistent with propagation at fast magnetohydrodynamic speed. The oscillations also create large-scale stripes of variations in the magnetosheath and modulate the mirror and electromagnetic ion cyclotron modes. We characterize the spatial-temporal properties of ULF waves at different phases of the variation. Less prominent EMIC and mirror mode wave activities near the center of magnetosheath are observed with decreasing upstream Mach number. The EMIC wave occurrence is strongly related to pressure anisotropy and β‖, both vary as a function of the upstream conditions, whereas the mirror mode occurrence is highly influenced by fast waves generated from upstream density variations.

We present results of noon–midnight meridional plane global hybrid-Vlasov simulations of the magnetotail ion dynamics under a steady southward interplanetary magnetic field using the Vlasiator model. The simulation results show magnetotail reconnection and formation of earthward and tailward fast plasma outflows. The hybrid-Vlasov approach allows us to study ion velocity distribution functions (VDFs) that are self-consistently formed during the magnetotail evolution. We examine the VDFs collected by virtual detectors placed along the equatorial magnetotail within earthward and tailward outflows and around the quasi-steady X line formed in the magnetotail at X≈-14RE. This allows us to follow the evolution of VDFs during earthward and tailward motion of reconnected flux tubes as well as study signatures of unmagnetized ion motion in the weak magnetic field near the X line. The VDFs indicate actions of Fermi-type and betatron acceleration mechanisms, ion acceleration by the reconnection electric field, and Speiser-type motion of ions near the X line. The simulated VDFs are compared and show good agreement with VDFs observed in the magnetotail by the Time History of Events and Macroscale Interactions during Substorms (THEMIS) and Acceleration, Reconnection, Turbulence and Electrodynamics of Moon's Interaction with the Sun (ARTEMIS) spacecraft. We find that the VDFs become more gyrotropic but retain transverse anisotropy and counterstreaming ion beams when being convected earthward. The presented global hybrid-Vlasov simulation results are valuable for understanding physical processes of ion acceleration during magnetotail reconnection, interpretation of in situ observations, and for future mission development by setting requirements on pitch angle and energy resolution of upcoming instruments.

Magnetosheath jets are regions of high dynamic pressure, which can traverse from the bow shock towards the magnetopause. Recent modelling efforts, limited to a single jet and a single set of upstream conditions, have provided the first estimations about how the jet parameters behave as a function of position within the magnetosheath. Here we expand the earlier results by doing the first statistical investigation of the jet dimensions and parameters as a function of their lifetime within the magnetosheath. To verify the simulation behaviour, we first identify jets from Magnetosphere Multiscale (MMS) spacecraft data (6142 in total) and confirm the Vlasiator jet general behaviour using statistics of 924 simulated individual jets. We find that the jets in the simulation are in quantitative agreement with the observations, confirming earlier findings related to jets using Vlasiator. The jet density, dynamic pressure, and magnetic field intensity show a sharp jump at the bow shock, which decreases towards the magnetopause. The jets appear compressive and cooler than the magnetosheath at the bow shock, while during their propagation towards the magnetopause they thermalise. Further, the shape of the jets flatten as they progress through the magnetosheath. They are able to maintain their flow velocity and direction within the magnetosheath flow, and they end up preferentially to the side of the magnetosheath behind the quasi-parallel shock. Finally, we find that Vlasiator jets during low solar wind Alfvén Mach number MA are shorter in duration, smaller in their extent, and weaker in terms of dynamic pressure and magnetic field intensity as compared to the jets during high MA.

Automatically adaptive grid resolution is a common way of improving simulation accuracy while keeping computational efficiency at a manageable level. In space physics, adaptive grid strategies are especially useful as simulation volumes are extreme, while the most accurate physical description is based on electron dynamics and hence requires very small grid cells and time steps. Therefore, many past global simulations encompassing, for example, near-Earth space have made tradeoffs in terms of the physical description and laws of magnetohydrodynamics (MHD) used that require less accurate grid resolutions. Recently, using supercomputers, it has become possible to model the near-Earth space domain with an ion-kinetic hybrid scheme going beyond MHD-based fluid dynamics. These simulations, however, must develop a new adaptive mesh strategy beyond what is used in MHD simulations. We developed an automatically adaptive grid refinement strategy for ion-kinetic hybrid-Vlasov schemes, and we implemented it within the Vlasiator global solar wind–magnetosphere–ionosphere simulation. This method automatically adapts the resolution of the Vlasiator grid using two indices: one formed as a maximum of dimensionless gradients measuring the rate of spatial change in selected variables and the other derived from the ratio of the current density to the magnetic field density perpendicular to the current. Both these indices can be tuned independently to reach a desired level of refinement and computational load. We test the indices independently and compare the results to a control run using static refinement. The results show that adaptive refinement highlights relevant regions of the simulation domain and keeps the computational effort at a manageable level. We find that the refinement shows some overhead in the rate of cells solved per second. This overhead can be large compared to the control run without adaptive refinement, possibly due to resource utilization, grid complexity, and issues in load balancing. These issues lay out a development roadmap for future optimizations. [ABSTRACT FROM AUTHOR]

Key Points: Question: Among patients with increased risk of postpartum venous thromboembolism, does a more selective protocol for initiating postpartum enoxaparin, compared with a standard risk-stratified protocol, decrease wound complications without increasing patient risk of venous thromboembolism? Findings: In this retrospective observational study, a more selective protocol for chemoprophylaxis resulted in a decrease in heparin (enoxaparin) administration (16% vs 8%). The selective protocol for postpartum enoxaparin was associated with a decrease in wound hematoma (0.7% vs 0.3% in the selective protocol group; adjusted odds ratio, 0.38; 95% CI, 0.21-0.67) without evidence of increase in venous thromboembolism (0.1% vs 0.1% in the selective protocol group; adjusted odds ratio, 0.40; 95% CI, 0.12-1.36). Meaning: A more selective protocol for postpartum enoxaparin was associated with decreased rates of wound hematomas without evidence of increased rates of postpartum thromboembolic events. Importance: In 2016, our institution adopted a pregnancy-related venous thromboembolism (VTE) prophylaxis protocol based on American College of Obstetricians and Gynecologists guidelines that recommended postpartum heparin-based chemoprophylaxis (enoxaparin) based on a risk-stratified algorithm. In response to increased wound hematomas without significant reduction in VTE using this protocol, a more selective risk-stratified approach was adopted in 2021. Objective: To evaluate outcomes of the more selective risk-stratified approach to heparin-based obstetric thromboprophylaxis (enoxaparin) protocol. Design, Setting, and Participants: Retrospective observational study of 17 489 patients who delivered at a single tertiary care center in the southeast US between January 1, 2016, and December 31, 2018 (original protocol), and between December 1, 2021, and May 31, 2023 (more selective protocol). Patients receiving outpatient anticoagulation for active VTE or high VTE risk during pregnancy were excluded. Exposure: Standard risk-stratified and more selective postpartum VTE chemoprophylaxis protocols. Main Outcomes and Measures: The primary outcome was clinical diagnosis of wound hematoma up to 6 weeks pos tpartum. The secondary outcome was new diagnosis of VTE up to 6 weeks post partum. We compared baseline characteristics and outcomes between groups and estimated adjusted odds ratios with 95% CIs of primary and secondary outcomes using the original protocol group as reference. Results: Of 17 489 patients included in the analysis, 12 430 (71%) were in the original protocol group and 5029 (29%) were in the more selective group. Rates of chemoprophylaxis decreased from 16% (original protocol) to 8% (more selective protocol). Patients in the more selective group were more likely to be older, be married, and have obesity or other comorbidities (hypertension, diabetes, cardiac disease). Compared with the original protocol, the more selective protocol was associated with a decrease in any wound hematoma (0.7% vs 0.3%; adjusted odds ratio [aOR], 0.38; 95% CI, 0.21-0.67), specifically due to a lower rate of superficial wound hematomas (0.6% vs 0.3%; aOR, 0.43; 95% CI, 0.24-0.75). There was no significant increase in VTE or individual types of VTE (0.1% vs 0.1%; aOR, 0.40; 95% CI, 0.12-1.36). Conclusions and Relevance: A more selective risk-stratified approach to an enoxaparin thromboprophylaxis protocol for VTE was associated with decreased rates of wound hematomas without increased rates of postpartum VTE. This observational study assesses incidence of wound hematoma diagnoses up to 6 weeks post partum among obstetric patients who received thromboprophylaxis according to less selective vs more selective hospital chemoprophylaxis protocols. [ABSTRACT FROM AUTHOR]

Simulations of the coupled ionosphere-magnetosphere system are a key tool to understand geospace and its response to space weather. For the most part, they are based on fluid descriptions of plasma (magnetohydrodynamics, MHD) formalism, coupled an electrostatic ionosphere. Kinetic approaches to modeling the global magnetosphere with a coupled ionosphere system are still a rarity. We present an ionospheric boundary model for the global near-Earth plasma simulation system Vlasiator. It complements the magnetospheric hybrid-Vlasov simulations with an inner boundary condition that solves the ionospheric potential based on field-aligned current and plasma quantities from the magnetospheric domain. This new ionospheric module solves the ionospheric potential in a height-integrated approach on an unstructured grid and couples back to the hybrid-kinetic simulation by mapping the resulting electric field to the magnetosphere's inner boundary. The solver is benchmarked against a set of well-established analytic reference cases, and we discuss the benefits of a spherical Fibonacci mesh for use in ionospheric modeling. Preliminary results from coupled global magnetospheric-ionospheric simulations are presented, showing formation of both Region 1 and Region 2 current systems. [ABSTRACT FROM AUTHOR]

Objective Little is known about the hospital outcomes of moderately preterm (MPT; 29 0/7–33 6/7 weeks gestational age) infants born to insulin-dependent diabetic mothers (IDDMs). We evaluated characteristics and outcomes of MPT infants born to IDDMs compared with those without IDDM (non-IDDM). Study Design Cohort study of infants from 18 centers included in the MPT infant database from 2012 to 2013. We compared characteristics and outcomes of infants born to IDDMs and non-IDDMs. Results Of 7,036 infants, 527 (7.5%) were born to IDDMs. Infants of IDDMs were larger at birth, more often received continuous positive pressure ventilation in the delivery room, and had higher risk of patent ductus arteriosus (adjusted relative risk or aRR: 1.49, 95% confidence interval [CI]: 1.20–1.85) and continued hospitalization at 40 weeks postmenstrual age (aRR: 1.55, 95% CI: 1.18–2.05). Conclusion MPT infants of IDDM received more respiratory support and prolonged hospitalizations, providing further evidence of the important neonatal health consequences of maternal diabetes. Key Points Little data are available on moderate preterm infants of IDDMs. MPT infants of IDDMs need more respiratory support. Longer neonatal intensive care unit stays among MPT infants of IDDMs. [ABSTRACT FROM AUTHOR]

Of the many families of cryptographic schemes proposed to be post-quantum, a relatively unexplored set of examples comes from group-based cryptography. One of the more central schemes from this area is the so-called Semidirect Product Key Exchange (SDPKE), a generalization of Diffie–Hellman Key Exchange that is plausibly post-quantum. In this report we survey the state of the literature relating to SDPKE, providing a high-level discussion of security, as well as a comprehensive overview of the proposed platforms and the main cryptanalytic ideas relevant to each. [ABSTRACT FROM AUTHOR]

Modern investigations of dynamical space plasma systems such as magnetically complicated topologies within the Earth's magnetosphere make great use of supercomputer models as well as spacecraft observations. Space plasma simulations can be used to investigate energy transfer, acceleration, and plasma flows on both global and local scales. Simulation of global magnetospheric dynamics requires spatial and temporal scales currently achievable through magnetohydrodynamics or hybrid-kinetic simulations, which approximate electron dynamics as a charge-neutralizing fluid. We introduce a novel method for Vlasov-simulating electrons in the context of a hybrid-kinetic framework in order to examine the energization processes of magnetospheric electrons. Our extension of the Vlasiator hybrid-Vlasov code utilizes the global simulation dynamics of the hybrid method whilst modelling snapshots of electron dynamics on global spatial scales and temporal scales suitable for electron physics. Our eVlasiator model is shown to be stable both for single-cell and small-scale domains, and the solver successfully models Langmuir waves and Bernstein modes. We simulate a small test-case section of the near-Earth magnetotail plasma sheet region, reproducing a number of electron distribution function features found in spacecraft measurements.

Kinetically driven plasma waves are fundamental for a description of the thermodynamical properties of the Earth's magnetosheath. The most commonly observed ion-scale instabilities are generated by temperature anisotropy of the ions, such as the mirror and proton cyclotron instabilities. We investigate here the spatial resolution dependence of the mirror and proton cyclotron instabilities in a global hybrid-Vlasov simulation using the Vlasiator model; we do this in order to find optimal resolutions and help future global hybrid-Vlasov simulations to save resources when investigating those instabilities in the magnetosheath. We compare the proton velocity distribution functions, power spectra and growth rates of the instabilities in a set of simulations with three different spatial resolutions but otherwise identical set-up. We find that the proton cyclotron instability is absent at the lowest resolution and that only the mirror instability remains, which leads to an increased temperature anisotropy in the simulation. We conclude that the proton cyclotron instability, its saturation and the reduction of the anisotropy to marginal levels are resolved at the highest spatial resolution. A further increase in resolution does not lead to a better description of the instability to an extent that would justify this increase at the cost of numerical resources in future simulations. We also find that spatial resolutions between 1.32 and 2.64 times the inertial length in the solar wind present acceptable limits for the resolution within which the velocity distribution functions resulting from the proton cyclotron instability are still bi-Maxwellian and reach marginal stability levels. Our results allow us to determine a range of spatial resolutions suitable for the modelling of the proton cyclotron and mirror instabilities and should be taken into consideration regarding the optimal grid spacing for the modelling of these two instabilities, within available computational resources.

Radial diffusion coefficients quantify non-adiabatic transport of energetic particles by electromagnetic field fluctuations in planetary radiation belts. Theoretically, radial diffusion occurs for an ensemble of particles that experience irreversible violation of their third adiabatic invariant, which is equivalent to a change in their Roederer L* parameter. Thus, the Roederer L* coordinate is the fundamental quantity from which radial diffusion coefficients can be computed. In this study, we present a methodology to calculate the Lagrangian derivative of L* from global magnetospheric simulations, and test it with an application to Vlasiator, a hybrid-Vlasov model of near-Earth space. We use a Hamiltonian formalism for particles confined to closed drift shells with conserved first and second adiabatic invariants to compute changes in the guiding center drift paths due to electric and magnetic field fluctuations. We investigate the feasibility of this methodology by computing the time derivative of L* for an equatorial ultrarelativistic electron population travelling along four guiding center drift paths in the outer radiation belt during a 5 minute portion of a Vlasiator simulation. Radial diffusion in this simulation is primarily driven by ultralow frequency waves in the Pc3 range (10–45 s period range) that are generated in the foreshock and transmitted through the magnetopause to the outer radiation belt environment. Our results show that an alternative methodology to compute detailed radial diffusion transport is now available and could form the basis for comparison studies between numerical and observational measurements of radial transport in the Earth’s radiation belts.

The authors comment on how to manage premature births at gestational ages near the limit of viability. Topics discussed include increase in NICU admissions at 22 weeks' gestation since 2008, according to a study of hospitals in 29 U.S. states, what families know about between-hospital differences in treatments and outcomes, and whether all hospitals should provide intensive interventions for deliveries at 22 to 24 weeks.