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The Discrete Element Method is widely employed for simulating granular flows, but conventional integration techniques may produce unphysical results for simulations with static friction when particle size ratios exceed R ≈ 3. These inaccuracies arise under certain circumstances because some variables in the velocity-Verlet algorithm are calculated at the half-timestep, while others are computed at the full timestep. To correct this, we develop an improved velocity-Verlet integration algorithm to ensure physically accurate outcomes up to the largest size ratios examined (R = 100). The implementation of this improved synchronized_verlet integration method within the LAMMPS framework is detailed, and its effectiveness is validated through a simple three-particle test case and a more general example of granular flow in mixtures with large size-ratios, for which we provide general guidelines for selecting simulation parameters and accurately modeling inelasticity in large particle size-ratio simulations. 

Lift and drag forces on moving intruders in flowing granular materials are of fundamental interest but have not yet been fully characterized. Drag on an intruder in granular shear flow has been studied almost exclusively for the intruder moving across flow streamlines, and the few studies of the lift explore a relatively limited range of parameters. Here, we use discrete element method simulations to measure the lift force,$$F_{{L}}$$, and the drag force on a spherical intruder in a uniformly sheared bed of smaller spheres for a range of streamwise intruder slip velocities,$$u_{{s}}$$. The streamwise drag matches the previously characterized Stokes-like cross-flow drag. However,$$F_{{L}}$$in granular shear flow acts in the opposite direction to the Saffman lift in a sheared fluid at low$$u_{{s}}$$, reaches a maximum value and then decreases with increasing$$u_{{s}}$$, eventually reversing direction. This non-monotonic response holds over a range of flow conditions, and the$$F_{{L}}$$versus$$u_{{s}}$$data collapse when both quantities are scaled using the particle size, shear rate and overburden pressure. Analogous fluid simulations demonstrate that the flow around the intruder particle is similar in the granular and fluid cases. However, the shear stress on the granular intruder is notably less than that in a fluid shear flow. This difference, combined with a void behind the intruder in granular flow in which the stresses are zero, significantly changes the lift-force-inducing stresses acting on the intruder between the granular and fluid cases. 

This dataset includes measurements of the dissolved isotope radium-226 in the South Pacific and Southern Ocean. Samples were collected on the US GEOTRACES GP17-OCE cruise (Papeete, Tahiti to Punta Arenas, Chile) on R/V Roger Revelle from December 2022 to January 2023. Radium-223, radium-224, and radium-228 data will be made available in the future. 

Introduction: Coronavirus disease 2019 (COVID-19) has had a profound impact globally, causing the death of millions of people and deeply affecting socio-psychological, human health, and economic systems, with some nations bearing a disproportionate burden. Despite obesity having been established as one of the major risk factors of COVID-19 severity and other degenerative diseases, the effects that dietary pattern intake plays in COVID-19 outcomes remain poorly understood. The goal of this study is to look into the connection between eating habits, the number of non-obese and obese people, and COVID-19 outcomes in countries with populations exhibiting normal Body Mass Index (BMI), which is an indicator of obesity. Methods: The analysis includes data from 170 countries. From the 170 countries, we focused on 53 nations where the average, BMI falls within the normal range (18.5 to 24.9). A subset of 20 nations was selected for a more detailed examination, comprising 10 nations with the lowest BMI values within the normal range (18.5-19.8) and 10 nations with the highest BMI values within the normal range (23.5-24.9). We used Artificial Intelligence (AI) and Machine Learning (ML) applications to evaluate key metrics, including dietary patterns (sugar and vegetable intake), obesity prevalence, incidence rate, mortality rate, and Case Fatality Rate (CFR). Results: The results demonstrate a significant correlation between higher obesity prevalence and increased COVID-19 severity, evidenced by elevated incidence, mortality, and CFRs in countries like North Macedonia and Italy. In contrast, nations such as Iceland and New Zealand with well-established healthcare systems revealed low mortality rate and case fatality rate despite variations in dietary habits. The study also revealed that vegetable consumption appears to provide a slight to significant protective effects, suggesting that dietary patters alone do not consistently predict COVID-19 Outcomes. Conclusion: Data generated from this study showed the crucial role of healthcare infrastructure along with the testing capacity and data reporting in influencing the success of pandemic responses. It also highlights the need of integrating public health strategies, which focus on obesity management and improvement of healthcare preparedness. In addition, AI-driven predictive modeling offers valuable insights that may guide pandemic response efforts in the future, thereby enhancing global health crisis management and mitigating the impact of future health emergencies. Keywords: COVID-19; Dietary patterns; Obesity; Artificial intelligence; Machine learning; Public health; Health care systems 

Abstract The striped emeralds (SomatochloraSelys) are a Holarctic group of medium‐sized metallic green dragonflies that mainly inhabit bogs and seepages, alpine streams, lakes, channels and lowland brooks. With 42 species they are the most diverse genus within Corduliidae (Odonata: Anisoptera). Systematic, taxonomic and biogeographic resolution withinSomatochloraremains unclear, with numerous hypotheses of relatedness based on wing veins, male claspers (epiproct and paraprocts) and nymphs. Furthermore,Somatochlora borisiwas recently described as a new genus (Corduliochlora) based on 17 morphological characters, but its position with respect toSomatochlorais unclear. We present a phylogenetic reconstruction ofSomatochlorausing Anchored Hybrid Enrichment (AHE) sequences of 40/42Somatochloraspecies (includingCorduliochlora borisi). Our data recover the monophyly ofSomatochlora, withC. borisirecovered as sister to the remainingSomatochlora. We also recover three highly supported clades and one of mixed support; this lack of resolution is most likely due to incomplete lineage sorting, third‐codon position saturation based on iterative analyses run on variations of our dataset and hybridization. Furthermore, we constructed a dataset for all species based on 20 morphological characters from the literature which were used to evaluate phylogenetic groups recovered with molecular data; the data support the validity ofCorduliochloraas a genus distinct fromSomatochlora. Finally, divergence time estimation and biogeographic analysis indicateSomatochloraoriginated in the Western North Hemisphere during the Miocene, with three dispersal events to the Eastern North Hemisphere (11, 7 and 5 Ma, respectively) across the Beringian Land Bridge. 

Abstract. Nitrous oxide (N2O) is a potent greenhouse gas emitted by oceanic and terrestrial sources, with its biogeochemical cycle influenced by both natural processes and anthropogenic activities. Current atmospheric N2O monitoring networks, including tall-tower and flask measurements, often overlook major marine hotspots, such as the eastern tropical Pacific Ocean. We present the first 15 months of high-frequency continuous measurements of N2O and carbon monoxide from the newly established Galapagos Emissions Monitoring Station (GEMS) in this region. Over this period, N2O mole fractions vary by approximately 5 ppb, influenced by seasonal trade winds, local anthropogenic emissions, and air masses transported from marine N2O hotspots. Notably, between February and April 2024, we observe high variability linked to the southward shift of the intertropical convergence zone and weakened trade winds over the Galapagos Islands. Increased variability during this period is driven by stagnant local winds, which accumulate emissions, and the mixing of air masses with different N2O content from the northern and southern hemispheres. The remaining variability is primarily due to differences in air mass transport and heterogeneity in surface fluxes from the eastern tropical Pacific. Air masses passing over the Peruvian and Chilean upwelling systems— key sources of oceanic N2O efflux — show markedly higher N2O mole fractions at the GEMS station. 

Abstract PremiseUnderstanding how population dynamics vary in space and time is critical for understanding the basic life history and conservation needs of a species, especially for narrow endemic species whose populations are often in similar environments and therefore at increased risk of extinction under climate change. Here, we investigated the spatial and temporal variation in population dynamics ofRanunculus austro‐oreganus, a perennial buttercup endemic to fragmented prairie habitat in one county in southern Oregon. MethodsWe performed demographic surveys of three populations ofR. austro‐oreganusover 4 years (2015–2018). We used size‐structured population models and life table response experiments to investigate vital rates driving spatiotemporal variation in population growth. ResultsOverall,R. austro‐oreganushad positive or stable stochastic population growth rates, though individual vital rates and overall population growth varied substantially among sites and years. All populations had their greatest growth in the same year, suggesting potential synchrony associated with climate conditions. Differences in survival contributed most to spatial variation in population growth, while differences in reproduction contributed most to temporal variation in population growth. ConclusionsPopulations of this extremely narrow endemic appear stable, with positive growth during our study window. These results suggest that populations ofR. austro‐oreganusare able to persist if their habitat is not eliminated by land‐use change. Nonetheless, its narrow distribution and synchronous population dynamics suggest the need for continued monitoring, particularly with ongoing habitat loss and climate change. 

Neurocordulia, commonly called shadowdragons, are crepuscular dragonflies, flying mainly at dusk. The genus comprises seven species, which occur across the eastern part of Canada and the United States. Here, we used targeted enrichment probes to sequence ~1000 loci for all specimens of each species, allowing for the first phylogenetic assessment of the genus. Additionally, we collected individuals of N. yamaskanensis from a population in Ontario, Canada, and used whole genome resequencing to estimate population structure. Beyond broadly reconstructing the phylogeny of Neurocordulia, we provided a comprehensive bibliography review of past research on the genus, a key to the species, and distribution models for each species. 

An inclusive and socially legitimate governance structure is absent to address concerns over new agricultural biotechnologies. Establishing an agricultural bioethics commission devoted to inclusive deliberation on ethics and governance in agricultural and food biotechnology is urgent. Highlighting the social and ethical dimensions of current agricultural bioengineering disputes in the food system, we discuss how a nationally recognized policy forum could improve decision-making and increase public understanding of the issues. We clarify ways the concepts that are used to categorize food and frame governance of food affect consumer choices, and how dissemination of information and the mode of dissemination can contribute to social inequities. We cite the record of medically-oriented bioethic commissions and the history of international bioethic commissions in support of our argument, and end by discussing what such a commission dedicated to agriculture and food issues could reasonably be expected to achieve.