In the field of parafoil airdrop path planning, the inherent complexity and time-sensitive nature of mission requirements necessitate rapid path generation through low-order mathematical models that approximate the system’s true dynamics. This study presents a novel sparse identification framework for constructing a parafoil path planning approximate model. Leveraging high-fidelity 9-degree-of-freedom (9 DOF) dynamic simulation data as training inputs, our method identifies simple nonlinear relationships between 3D positional coordinates (for spatial targeting) and yaw angle (for directional control), which are critical path planning parameters. Compared to conventional 4 DOF models, experimental validation using field airdrop data reveals that the proposed sparse model achieves enhanced predictive accuracy while maintaining computational efficiency. Quantitative analysis demonstrates reductions in root mean square error (RMSE) by approximately 12.96% (horizontal position), 54.44% (height) and 37.96% (yaw angle). The efficacy is further confirmed through successful fixed-point homing across diverse initial deployment scenarios, underscoring its potential for parafoil path planning.

The atomic bombings of Hiroshima and Nagasaki reshaped international politics and the field of International Relations. But one question—“How should the atomic bomb be used?”—has been largely overlooked in political science. This article recovers American deliberations on alternative nuclear use options before August 1945, including the “noncombat demonstration,” targeting military installations, giving advance warning, and striking more symbolically valuable cities. We develop theoretical insights on the value of staging violent spectacles and the emotive power of visible destruction. We then use a wide range of sources to show that U.S. leaders selected an ostentatiously lethal means of atomic debut due to concerns about conventional military inferiority vis-à-vis the Soviet Union, the desire to instill a widespread view of the bomb’s revolutionary character, and the imperative of shaping the postwar international order. This study advances our understanding of the post-1945 international order and the performative dimensions of political violence.

Twin children are more likely to die than singletons. This is an additional burden in sub-Saharan African (SSA) countries, as child mortality levels are already higher than anywhere else. This article provides estimates of under-5 mortality rates (U5MRs) for twins and singletons in SSA from 1986 to 2016. It describes the geographical variations and changes over time. It also describes the variation of twins’ excess mortality according to age from 0 to 5 years. Additionally, it analyzes the factors associated with twins’ excess mortality. We used data from 156 national surveys from 42 countries. We estimated U5MRs for twins and single children and built a Cox model to analyze factors associated with excess mortality among twins. Although child mortality has declined on the continent, twins’ excess mortality remains very high. U5MRs are, on average, 3 times higher among twins than singletons. The Cox model shows that all other things being equal, the adjusted hazard ratio of under-5 mortality (U5M) is 3.2 (2.9−3.3; p < .001) times higher among twins than singletons. The main factors associated with excess mortality risks among twins are biomedical and nutritional features, such as low birth weight, non-use of cesarean section delivery, and lack of breastfeeding. Health policy makers in SSA should be aware of the vulnerability of twins, and interventions to prevent their early deaths should be considered.

Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae) is a significant pest of wheat, Triticum aestivum Linnaeus (Poaceae), in Canada. Monitoring currently relies on labour-intensive counts of ovipositing females. Although traps baited with S. mosellana pheromone are used as decision support tools in the United Kingdom, in Canada, they are considered reliable only to indicate adult activity. Recent findings show that variability in pheromone release from commercial lures affects the number of midges captured and limits the reliability of pheromone monitoring. Here, two lure types and two trap types were compared for their ability to attract and retain S. mosellana males. We then compared the number of males captured in pheromone traps with the information provided by other monitoring tools, including emergence traps, soil cores, and ovipositing female counts. Jackson traps with Trécé rubber septa lures captured the most midges. The number of males captured in pheromone-baited traps was not related to overwintering, ovipositing, or emerging populations, suggesting that pheromone traps may not accurately reflect S. mosellana populations under field conditions. Variability in extracted pheromone amount between lures, regional climate, and Canada’s vast wheat-growing area may limit the development of an effective pheromone-based decision support tool for this region. Nevertheless, refinement of lure formulation, standardisation of trapping protocols, and integration of complementary monitoring approaches may enhance trap reliability and support a stronger monitoring system.

Pelmatozoa is an informal grouping of filter-feeding echinoderms including crinoids, paracrinoids, rhombiferans, and eocrinoids that possess a theca, an erect stalk, and feeding appendages. Although crinoids were major constituents of marine communities with high diversity and abundance throughout the Paleozoic, most other pelmatozoans had relatively low species diversity and/or short temporal durations. It has been proposed that these different diversification trajectories could have resulted from crinoids outcompeting other filter-feeding pelmatozoans during the early Paleozoic, although this hypothesis involving niche overlap has never been formally tested. Here, we tested this hypothesis using the incredibly diverse pelmatozoan fauna of the Late Ordovician (Sandbian) Bromide Formation of Oklahoma, which preserves a rich, ecologically complex fauna that developed as a result of the Great Ordovician Biodiversification Event. We developed a framework to quantitatively characterize pelmatozoan feeding ecology using multivariate analysis of ecomorphological traits and explored niche space occupation and potential competition between crinoids, rhombiferans, paracrinoids, eocrinoids, and diploporans from the Bromide fauna. Results revealed key ecological factors controlling niche differentiation and showed that crinoids, paracrinoids, and rhombiferans occupy nonoverlapping regions of niche space, indicating competition between groups was unlikely. Although the competition hypothesis was not supported, narrow niche space occupation suggests that paracrinoids and rhombiferans were more ecologically limited than crinoids, which might have played a role in their differential diversification dynamics. These results elucidate both the nature of interactions between pelmatozoan taxa and the potential mechanisms driving their evolutionary trajectories, as well as the complexity of ecological communities that arose during the Ordovician radiation.

A seminal result of Komlós, Sárközy, and Szemerédi states that any $n$-vertex graph $G$ with minimum degree at least $(1/2+\alpha )n$ contains every $n$-vertex tree $T$ of bounded degree. Recently, Pham, Sah, Sawhney, and Simkin extended this result to show that such graphs $G$ in fact support an optimally spread distribution on copies of a given $T$, which implies, using the recent breakthroughs on the Kahn-Kalai conjecture, the robustness result that $T$ is a subgraph of sparse random subgraphs of $G$ as well. Pham, Sah, Sawhney, and Simkin construct their optimally spread distribution by following closely the original proof of the Komlós-Sárközy-Szemerédi theorem which uses the blow-up lemma and the Szemerédi regularity lemma. We give an alternative, regularity-free construction that instead uses the Komlós-Sárközy-Szemerédi theorem (which has a regularity-free proof due to Kathapurkar and Montgomery) as a black box. Our proof is based on the simple and general insight that, if $G$ has linear minimum degree, almost all constant-sized subgraphs of $G$ inherit the same minimum degree condition that $G$ has.

In a retrospective cohort of 6363 neonates admitted to three NICUs, there was no reduction in Staphylococcus aureus acquisition when comparing pre- and post-pandemic incidence rates. While additional infection prevention practices introduced during the pandemic helped prevent SARS-CoV-2 transmission, these practices may not have reduced S. aureus transmission to infants.

We analyze the extent to which the prospects for economic development may relate to the environmental damages associated with economic activities. We consider an economic growth framework in which production activities generate polluting emissions which in turn negatively affect production capabilities, and publicly-funded abatement is pursued to mitigate such effects. Since the time preference is endogenously related to capital, abatement affects the size of the discount factor through its implications on capital accumulation. We show that the elasticity of environmental damages affects the optimal tax rate and thus the abatement level, which in turn determines whether the economy will end up in a stagnation or growth regime. This suggests that the cross-country heterogeneity in environmental damages may explain the different development patterns experienced by industrialized and developing economies. Our results are robust to the presence of productive public spending and two alternative forms of capital (clean and dirty capital).