We use direct numerical simulations to examine the onset of stratified turbulence triggered by the zigzag instability recently identified in columnar Taylor–Green vortices (Guo et al. 2024, J. Fluid Mech., vol. 997, A34) and its role in layer formation within the flow. The study focuses on Froude numbers $0.125 \leqslant \textit{Fr} \leqslant 2.0$ and Reynolds numbers ${\textit{Re}}$ ranging from 800 to 3200. The breakdown of the freely evolving vortex array is driven by local density overturns, combining shear and convective mechanisms initiated by the primary zigzag instability. Our results show a linear relationship between the peak buoyancy Reynolds number ${{\textit{Re}}}_b^{\star }$, driven by the zigzag instability, and ${\textit{Re}}\, {\textit{Fr}}^2$. When the flow does not exhibit local shear or convective instability, the value of ${{\textit{Re}}}_b^{\star }$ falls below unity. Both density and momentum layers arise from the zigzag instability: horizontal velocity layers are strong and persistent, while density layers are weaker and more transient. The vertical scale of the mean shear layers increases with ${\textit{Fr}}$ for ${\textit{Fr}} \leqslant 1$, shows weak dependence on ${\textit{Re}}$, and agrees well with the length scale associated with the fastest-growing linear mode of the zigzag instability. Further analysis in the sorted buoyancy coordinate highlights the role of density overturns caused by the zigzag instability in forming buoyancy layers during the transition to turbulence.

Automatic visual localization of electric vehicle (EV) charging ports presents significant challenges in uncertain environments, such as varying surface textures, reflections, lighting and observation distance. Existing methods require extensive real-world training data and well-focused images to achieve robust and accurate localization. However, both requirements are difficult to meet under variable and unpredictable conditions. This paper proposes a 2-stage vision-based localization approach. Firstly, the image synthesis technique is used to reduce the cost of real-world data collection. A task-oriented parameterization protocol (TOPP) is proposed to optimize the quality of the synthetic images. Secondly, an autofocus and servoing strategy is proposed. A hybrid detector is employed to enhance sharpness assessment performance, while a visual servoing method based on single exponential smoothing (SES) is developed to enhance stability and efficiency during the search process. Experiments were conducted to evaluate image synthesis efficiency, detection accuracy, and servoing performance. The proposed method achieved 99% detection accuracy on the real-world port images, and guided the robot to the optimal imaging position within 16 s, outperforming comparable approaches. These results highlight its potential for robust automated charging in real-world scenarios.

The incorporation of trace metals into land snail shells may record the ambient environmental conditions, yet this potential remains largely unexplored. In this study, we analyzed modern snail shells (Cathaica sp.) collected from 16 sites across the Chinese Loess Plateau to investigate their trace metal compositions. Our results show that both the Sr/Ca and Ba/Ca ratios exhibit minimal intra-shell variability and small inter-shell variability at individual sites. A significant positive correlation is observed between the shell Sr/Ca and Ba/Ca ratios across the plateau, with higher values being recorded in the northwestern sites where less monsoonal rainfall is received. We propose that shell Sr/Ca and Ba/Ca ratios, which record the composition of soil solution, may be controlled by the Rayleigh distillation in response to prior calcite precipitation. Higher rainfall amounts may lead to a lower degree of Rayleigh distillation and thus lower shell Sr/Ca and Ba/Ca ratios. This is supported by the distinct negative correlation between summer precipitation and shell Sr/Ca and Ba/Ca ratios, enabling us to reconstruct summer precipitation amounts using the Sr/Ca and Ba/Ca ratios of Cathaica sp. shells. The potential application of these novel proxies may also be promising for other terrestrial mollusks living in the loess deposits globally.

Background: While efgartigimod usage is expected to reduce immunoglobulin (IG) utilization, evidence in clinical practice is limited. Methods: In this retrospective cohort study, patients with gMG treated with efgartigimod for ≥1-year were identified from US medical/pharmacy claims data (April 2016-January 2024) and data from the My VYVGART Path patient support program (PSP). The number of IG courses during 1-year before and after efgartigimod initiation (index date) were evaluated. Patients with ≥6 annual IG courses were considered chronic IG users. Myasthenia Gravis Activities of Daily Living (MG-ADL) scores before and after index were obtained from the PSP where available. Descriptive statistics were used without adjustment for covariates. Results: 167 patients with ≥1 IG claim before index were included. Prior to efgartigimod initiation, the majority of patients (62%) received IG chronically. During the 1-year after index, the number of IG courses fell by 95% (pre: 1531, post: 75). 89% (n=149/167) of patients fully discontinued IG usage. Mean (SD) best-follow up MG-ADL scores were significantly reduced after index (8.0 [4.1] to 2.8 [2.1], P<0.05, n=73/167, 44%). Conclusions: Based on US claims, IG utilization was substantially reduced among patients who continued efgartigimod for ≥1-year, with patients demonstrating a favorable MG-ADL response.

Background: Generalized myasthenia gravis (gMG) is a potentially life threatening chronic autoimmune disease that can impair patients’ ability to work effectively and increase reliance on public support benefits. A public economic framework was used to explore how treatment influences patients’ and caregivers’ economic activity, including tax revenues and public support in Canada. Methods: Natural history of gMG was simulated using a multi-state Markov cohort model. Health states were based on MG Activities of Daily Living (MG-ADL) total score in patients with AChR-Ab+ refractory gMG. Treatment, costs, and economic outcomes of patients taking efgartigimod were compared with alternative therapeutic options. Canadian public support benefits were based on official government sources. Results: Improved MG-ADL states predict higher workforce participation, lower rates of disability and less caregiving needs, resulting in higher tax revenues and less public support costs. Compared to alternative therapeutic options, efgartigimod is estimated to yield lifetime fiscal gains of $458,755 that exceed the incremental cost of $291,073, suggesting the Canadian government receives $1.6 for every $1.0 spent on efgartigimod for the treatment of gMG. Conclusions: Compared with alternative options, efgartigimod generated a positive fiscal return for the Canadian governments with additional savings from disease management, public benefits, and averted tax revenue losses.

The whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) is economically one of the most threatening pests in tomato cultivation, which not only causes direct damage but also transmits many viruses. Breeding whitefly-resistant tomato varieties is a promising and environmentally friendly method to control whitefly populations in the field. Accumulating evidence from tomato and other model systems demonstrates that flavonoids contribute to plant resistance to herbivorous insects. Previously, we found that high flavonoid-producing tomato line deterred whitefly oviposition and settling behaviours, and was more resistant to whiteflies compared to the near-isogenic low flavonoid-producing tomato line. The objective of the current work is to describe in detail different aspects of the interaction between the whitefly and two tomato lines, including biochemical processes involved. Electrical penetration graph recordings showed that high flavonoid-producing tomato reduced whitefly probing and phloem-feeding efficiency. We also studied constitutive and induced plant defence responses and found that whitefly induced stronger reactive oxygen species accumulation through NADPH oxidase in high flavonoid-producing tomato than in low flavonoid-producing tomato. Moreover, whitefly feeding induced the expression of callose synthase genes and resulted in callose deposition in the sieve elements in high flavonoid-producing tomato but not in low flavonoid-producing tomato. As a consequence, whitefly feeding on high flavonoid-producing tomato significantly decreased uptake of phloem and reduced its performance when compared to low flavonoid-producing tomato. These results indicate that high flavonoid-producing tomato provides phloem-based resistance against whitefly infestation and that the breeding of such resistance in new varieties could enhance whitefly management.

This study explores an emerging yet under-researched group within the Chinese bureaucratic system: grassroots female civil servants. Although there is a growing focus in academia on female officials in China, existing research mainly concentrates on the gender representation and career pathways of high-ranking female officials. This research delves into the work and life choices faced by female civil servants in local governments. Despite official discourse advocating for gender equality, interviews with 21 female public servants from a poverty-stricken county in northern China reveal that the demands of local government work and gender norms impose a double burden on them. Although the civil service is known for its stability, these women often have to put in extra effort into demanding and exhausting jobs, frequently sacrificing promotion opportunities to balance family and caregiving responsibilities. However, they seldom express dissatisfaction with this situation, reflecting the entrenched nature of gender role perceptions. This study provides a new explanation for the underrepresentation of female officials at higher levels from a grassroots perspective and reveals the impact of overloaded bureaucratic work on career mobility.

Determining the factors that impact the risk for infection with SARS-CoV-2 is a priority as the virus continues to infect people worldwide. The objective was to determine the effectiveness of vaccines and other factors associated with infection among Canadian healthcare workers (HCWs) followed from 15 June 2020 to 1 December 2023. We also investigate the association between antibodies to SARS-CoV-2 and subsequent infections with SARS-CoV-2. Of the 2474 eligible participants, 2133 (86%) were female, 33% were nurses, the median age was 41 years, and 99.3% had received at least two doses of COVID-19 vaccine by 31 December 2021. The incidence of SARS-CoV-2 was 0.91 per 1000 person-days. Prior to the circulation of the Omicron variants, vaccine effectiveness (VE) was estimated at 85% (95% CI 1, 98) for participants who received the primary series of vaccine. During the Omicron period, relative adjusted VE was 43% (95% CI 29, 54), 56% (95% CI 42, 67), and 46% (95% CI 24, 62) for 3, 4, and ≥ 5 doses compared with those who received primary series after adjusting for previous infection and other covariates. Exposure to infected household members, coworkers, or friends in the previous 14 days were risk factor for infection, while contact with an infected patient was not statistically significant. Participants with higher levels of immunoglobulin G (IgG) anti-receptor binding domain (RBD) antibodies had lower rates of infection than those with the lowest levels. COVID-19 vaccines remained effective throughout the follow-up of this cohort of highly vaccinated HCWs. IgG anti-RBD antibody levels may be useful as correlates of protection for issues such as vaccine development and testing. There remains a need to increase the awareness among HCWs about the risk of contracting SARS-CoV-2 from contacts at a variety of venues.

Double aortic arch is an exceedingly rare congenital vascular anomaly, and its association with anomalous origins of the vertebral arteries is even more uncommon. Enhanced computed tomography revealed a double aortic arch with the left common carotid artery, left vertebral artery, and left subclavian artery originating from the left arch, and the right common carotid artery, right vertebral artery, and right subclavian artery arising from the right arch. To our knowledge, this is the first report of a double aortic arch with six distinct vessels originating from both arches. Enhanced CT should be considered in double aortic arch patients to identify such anomalous origins of branch arteries.

Previous studies have suggested that nature contact is a protective factor for problem behavior in children. However, there remains a significant gap in research exploring the reciprocal relationship between nature contact and children’s problem behavior, as well as the underlying mechanisms driving this relationship. This study employed a longitudinal three-wave design involving 516 children in China (268 girls, Mage = 10.88 ± 0.66 years old at Time 3). Cross-lagged analyses indicated that nature contact and problem behavior negatively predicted each other over time, and prosocial behavior bidirectionally mediated the relationship between nature contact and problem behavior. These results provided evidence for the relationships among nature interaction, social development, and behavioral development in children. These findings suggested that promoting prosocial behavior could reduce problem behavior and enhance nature engagement, potentially serving as a strategy to foster comprehensive development in children.

Removing liquid from a channel is an important process. In a horizontal slit in the presence of a downward gravity field, two distinct liquid states were commonly observed: gravity-driven liquid non-occlusion and liquid plug (Parry et al. 2012 Phys. Rev. Lett. 108, 246101). A wetting-driven non-occlusion at some contact angles was induced by insertion of a rod into a horizontal tube at an eccentric position (Tan et al. 2022 J. Fluid Mech. 946, A7). Insertion of a plate into a horizontal slit may enhance the capacity of removing liquid. This situation is theoretically investigated, and the theoretical results are mutually verified by a computational fluid dynamics (CFD) numerical method that is first employed to determine the critical non-occlusion conditions. Four types of liquid states are observed. The effects of contact angles, plate position and Bond number (measured by downward gravitational force relative to surface tension force) on different types of liquid states are analysed. This paper additionally provides a CFD numerical method for understanding the conditions for the stability and existence of the liquid plugs in complex situations (e.g. considering the effect of the sidewalls, or when a rod or plate is inserted into a circular, elliptical or polygonal tube) in the future.

Pre-pregnancy obesity (ppOB) is linked to pregnancy complications and abnormal fetal growth through placental mechanisms, and long non-coding RNAs (lncRNAs) may play an epigenetic role in these processes. We investigated overall and sex-specific associations of pre-pregnancy body mass index (ppBMI), ppOB, and birthweight with placental lncRNA transcripts in two birth cohorts. Study participants were mother-child dyads recruited to the CANDLE (Memphis, TN)(n = 725) and GAPPS (Seattle and Yakima, WA)(n = 159) cohorts. Maternal ppBMI was assessed at enrollment using interviewer-administered questionnaires. LncRNAs (1,077 and 1,033 for CANDLE and GAPPS, respectively) were sequenced from placental samples collected at birth. Placental lncRNA was regressed on ppBMI, ppOB (ppBMI ≥30kg/m2), or continuous birthweight in cohort-specific weighted linear models controlling for a priori-specified confounders and experimental variables. Potential effect modification by infant-sex was examined in sex-stratified analyses and models including BMI-infant-sex interaction terms. No lncRNA transcripts were significantly associated with ppBMI, ppOB, or birthweight in primary models. Among male infants in CANDLE, expression of three lncRNA transcripts (ERVH48-1, AC139099.1, CEBPA-DT) was associated with ppBMI and one transcript (AC104083.1) with birthweight. In GAPPS, ppBMI was associated with two lncRNA transcripts (AP000879.1 and AL365203.2) among males, and birthweight was associated with 17 lncRNA transcripts (including LINC02709, KANSL1-AS1, DANCR, EPB41L4A-AS1, and GABPB1-AS1) among females. No BMI-infant-sex interactions were observed. Though many of these potential associations are for uncharacterized transcripts, several identified lncRNAs (e.g., ERVH48-1 and CEBPA-DT) have been linked to pathways controlling cancer or placental growth, trophoblast differentiation, and gene expression. These associations warrant validation in future studies.