Modified ascent sequences, initially defined as the bijective images of ascent sequences under a certain hat map, have also been characterized as Cayley permutations where each entry is a leftmost copy if and only if it is an ascent top. These sequences play a significant role in the study of Fishburn structures. In this paper, we investigate (primitive) modified ascent sequences avoiding a pattern of length 4 by combining combinatorial and algebraic techniques, including the application of the kernel method. Our results confirm several conjectures posed by Cerbai.

The experimental investigation focuses on the effects of a short splitter plate on the flow physics of a circular cylinder in proximity to a wall by particle image velocimetry. The Reynolds number is Re = 3900, and the near-wall cylinder is immersed in turbulent boundary layer flow. Three gap ratios (i.e. $G/D$ = 0.25, 0.5 and 1) are considered, and the splitter plate length is $L/D=0$, 0.25, 0.5, 0.75 and 1. For $G/D$ = 0.5 and 1, as $L/D$ increases from 0 to 1, the splitter plate facilitates the cylinder shear layers to elongate downstream, and the vortex formation length is increased, which leads to the increase of the range of the recirculation region. For $G/D$ = 0.25, the wall suppression on the wake vortex formation is enhanced, and the variations of the vortex formation length and the range of the recirculation region with $L/D$ are small. The Strouhal number St presents a decrease with increasing $L/D$ for the three gap ratios. The effects of $L/D$ on the vortex evolution are revealed. For $G/D$ = 0.5 and 1, as $L/D$ increases, the induction of the lower wake vortex on the wall secondary vortex becomes weaker due to the reduction in strength of the wake vortex and the increase of the vortex formation length. Additionally, the wake fluctuation intensity is decreased with the increase of $L/D$ due to the splitter plate suppression. For $G/D$ = 0.25, theL/D influences on evolution of the wake vortices and wall secondary vortex are small, which result in weaker variation of the wake fluctuation intensity with $L/D$.

In complex work environments, improving efficiency and stability is an important issue in robot path planning. This article proposes a new path optimization algorithm based on pseudospectral methods. The algorithm includes an adaptive weighting factor in the objective function, which automatically adjusts the quality of the path while satisfying the performance indicators of the shortest time. It also considers kinematic, dynamic, boundary, and obstacle constraints, and applies the Separating Axis Theorem collision detection method to improve computational efficiency. To discretize the continuous path optimization problem into a nonlinear programming problem, the algorithm utilizes Chebyshev polynomials for the interpolation of state and control variables, along with the adoption of the Lagrange interpolation polynomial to approximate the curve. Finally, it solves the nonlinear programming problem numerically using CasADi, which supports automatic differentiation. The results of the simulation demonstrate that the path optimized by the adaptive-weight pseudospectral method can satisfy various constraints and optimization objectives simultaneously. Experimental verification confirms the efficiency and feasibility of the proposed algorithm.

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.

The perinatal period has gained increasing attention from developmental psychopathologists; however, experiences during birth have been minimally examined using this framework. The current study aimed to evaluate longitudinal associations between childhood maltreatment, negative birth experiences, and postpartum mental health across levels of self-reported emotion dysregulation and respiratory sinus arrhythmia (RSA). Expectant mothers (N = 223) participated in a longitudinal study from the third trimester of pregnancy to 7 months postpartum. Participants contributed prenatal resting RSA and completed questionnaires prenatally, 24 hours after birth, and 7 months postpartum. Results indicated that more childhood maltreatment was associated with higher birth fear and postpartum anxiety and depressive symptoms. Resting RSA moderated the association between childhood maltreatment and birth fear, such that more childhood maltreatment and higher resting RSA were associated with increased birth fear. Additionally, self-reported prenatal emotion dysregulation moderated the association between childhood maltreatment and postpartum depressive symptoms, such that more childhood maltreatment and higher emotion dysregulation were associated with increased depressive symptoms. Emotion dysregulation across multiple levels may amplify vulnerability to negative birth experiences and postpartum psychopathology among individuals with childhood maltreatment histories. Thus, emotion dysregulation in the context of trauma-informed care may be worthwhile intervention targets during the perinatal period.

Recent advancements in data science and artificial intelligence have significantly transformed plant sciences, particularly through the integration of image recognition and deep learning technologies. These innovations have profoundly impacted various aspects of plant research, including species identification, disease detection, cellular signaling analysis, and growth monitoring. This review summarizes the latest computational tools and methodologies used in these areas. We emphasize the importance of data acquisition and preprocessing, discussing techniques such as high-resolution imaging and unmanned aerial vehicle (UAV) photography, along with image enhancement methods like cropping and scaling. Additionally, we review feature extraction techniques like colour histograms and texture analysis, which are essential for plant identification and health assessment. Finally, we discuss emerging trends, challenges, and future directions, offering insights into the applications of these technologies in advancing plant science research and practical implementations.

Grounded in institutional theory, this study delves into the heterogeneous responses of politically connected top executives (PCTEs) to uniform institutional requirements for corporate environmental responsibility (CER). Specifically, we scrutinized the moderating role of organizational visibility in shaping the association between PCTEs and both environmentally responsible and irresponsible practices. Analyzing data from listed Chinese firms in heavily polluting industries spanning from 2010 to 2018, the findings indicate that PCTEs contribute to an increase in firms’ environmentally responsible activities and a decrease in their environmentally irresponsible activities. Notably, the impact on environmentally responsible activities is significant only for privately controlled PCTEs. Furthermore, the moderating influence of organizational visibility is validated. The implications of these findings for the broader research on political connections and CER are thoroughly discussed.

The Richtmyer–Meshkov instability at gas interfaces with controllable initial perturbation spectra under reshock conditions is investigated both experimentally and theoretically. A soap-film method is adopted to generate well-defined single-, dual- and triple-mode air/SF$_6$ interfaces. By inserting an acrylic block into the test section, a reflected shock with controllable reshock timing is created. The results reveal a complex relationship between the post-reshock perturbation growth rate and the pre-reshock interface morphology. For single-mode interfaces, the post-reshock growth rate exhibits a strong dependence on pre-reshock conditions. In contrast, for multi-mode interfaces, this dependence weakens significantly due to mode-coupling effects. It is found that, following reshock, each fundamental mode develops independently and later is significantly influenced by mode-coupling effects. Based on this finding, we propose an empirical model that matches the initial linear growth rate and the asymptotic growth rate, accurately predicting the evolution of fundamental modes from early to late stages across all three configurations. Furthermore, a theoretical formula is derived, linking the empirical coefficient in the model of Charakhch’An (2020 J. Appl. Mech. Tech. Phys. vol. 41, no. 1, pp. 23–31) to the initial perturbation. This provides a unified framework to explain the varying dependence of post-reshock growth rates on pre-reshock morphology observed in previous experiments.

Yiyang Dahegu rice (YyDHG) is an important agricultural specialty of Yiyang County, Jiangxi Province, and it is also a significant component of the local cultural and economic development. In this experiment, 89 samples of Dahegu rice (DHG) were collected from Jiangxi Province, including 52 samples of YyDHG and 37 samples of DHG from other regions within Jiangxi Province (oDHG). Comprehensive analysis was conducted using polyacrylamide gel electrophoresis, field phenotypic observation, population structure analysis and quality analysis. The results of variety identification indicated that the 89 samples actually comprised 52 distinct varieties, including 19 varieties of YyDHG. Population analysis has revealed rich genetic diversity among DHG varieties within Jiangxi Province, yet no significant subpopulation differentiation was observed between YyDHG and oDHG. Quality experiments demonstrated that YyDHG exhibits significant differences in appearance quality from oDHG, but no notable differences in milling quality or cooked taste and flavour. This suggests that the competitiveness of YyDHG in the market may not entirely depend on its unique quality characteristics, but rather more on its cultural value and brand effect. This experiment conducted a comprehensive analysis of the variety characteristics, genetic diversity and quality traits of YyDHG. Not only does it provide a scientific basis for the breeding and germplasm resource conservation of YyDHG, but it also holds positive implications for promoting the development of its industry.

A systematic study is conducted both experimentally and theoretically on the wake-induced vibration of an inelastic or zero structural stiffness cylinder placed behind a perfectly elastic or rigid cylinder. The mass ratio m* of the inelastic cylinder is 11.1. The spacing ratio L/D is 2.0–6.0, where L is the distance between centers of the two cylinders, and D is the cylinder diameter. The range of Reynolds number Re is 1.97 × 103–1.18 × 104. It has been found that the inelastic cylinder becomes aerodynamically elastic because the cylinder and the fluctuating wake interact, inducing an effective stiffness and thus giving rise to an aeroelastic natural frequency. This frequency depends on the added mass, fluid damping and flow-induced stiffness and is always smaller than the vortex shedding frequency, irrespective of Re and L/D. The wake-induced vibration of the inelastic cylinder may be divided into a desynchronisation branch and a galloping branch. The vibration amplitude jumps greatly at the transition from desynchronisation to galloping for L/D = 2.0–4.5 but not so for L/D = 5.0–6.0. The flow-induced stiffness is linearly correlated with Re, generally higher in the reattachment regime than in the coshedding regime and smaller in galloping than in desynchronisation. Other aspects of the inelastic cylinder are also investigated in detail, including the dependence on Re of the Strouhal numbers, hydrodynamic forces, phase lag between lift and displacement and flow characteristics.

During the Cold War, various political forces sought to shape the mindset of the Chinese diaspora. One understudied cultural influence that played an important role in reaching overseas Chinese was Chinese Christian literature. Focusing on Dengta (Lighthouse, 1956–1967), the first Chinese Christian magazine aimed at non-Christian communities in the diaspora, this study examines how the magazine developed an evangelical discourse that engaged with the cultural and spiritual identities of the Chinese diaspora amid political and ideological conflicts. Published in Hong Kong, which emerged as a hub for Chinese Christian literature in the post-war period, the magazine reflects a pivotal shift in Chinese Christian publishing: the start of a global movement aimed at evangelizing overseas Chinese. To appeal to the diaspora, Dengta adopted an ethnic and cultural rhetoric of Chineseness and presented Christian ideals in a context that resonated with the experiences of the Chinese diaspora. I argue that the Chineseness promoted by Dengta helped construct a transregional and transnational sense of belonging for overseas Chinese by framing a blend of traditional Chinese culture and modern knowledge within a Christian cosmic worldview. This study foregrounds the evangelical efforts of Christian literary workers to shape the diasporic experience amid the political tensions of the Cold War.

During the 2016 and 2017 fieldwork seasons at the site of Qijiaping in Guanghe County, Gansu Province, China, the team of the Tao River Archaeology Project excavated a large intact kiln. The kiln is well preserved, and the first of its kind reported in an archaeological excavation in this region. Several lines of evidence demonstrate that this was a roof tile kiln used during the Song period (ad 960–1279), possibly associated with the construction and maintenance of defensive facilities during the time of Northern Song (ad 1079–1127) occupation of the region— an era of conflict with the Western Xia (ad 982–1227). Inside the flues of the kiln were many objects disposed of when the kiln was put out of commission. Among these objects is a stone phallus, an object that reflects a gendered aspect of technology and manufacturing associated with this kiln or its decommissioning and more broadly the gendered social landscape of the Tao River valley during the Northern Song occupation of the region.

There are multiple equilibrium points in the launching and unfolding process of the multi-body aircraft. Different equilibrium points exhibit different stability characteristics and change with parameters such as connection method. The changes in stability characteristics can also lead to the inability of multi-body aircraft to achieve stable deployment. To solve these problems, the dynamic stability of multi-body aircraft during falling is analysed based on bifurcation theory in this paper. In this paper, Lagrange multiplier method is used to establish the multi-body dynamics model of the multi-body aircraft, and the curly spring torque model is added. In order to consider the coupling effect between the wings and the influence of the relative motion between the flight units on the aerodynamic force, the reference angle-of-attack, the reference sideslip angle, the relative attitude angle and the relative attitude angular velocity between the flight units were introduced as new variables to establish the aerodynamic model of the multi-body aircraft. Based on the equilibrium equations, the equilibrium curve of the two-body aircraft is obtained by using the joint stiffness coefficient as the continuous variable parameter. The stability of the equilibrium point domain on each equilibrium curve was analysed by using linearised theory. The dynamic characteristics of the launching and unfolding process of the two-body aircraft were analysed using bifurcation theory, and the stable domain was obtained regarding the initial folding angle and connection stiffness coefficient. The influence of initial folding angle and connection stiffness coefficient on the dynamic characteristics of the launching and unfolding process and the meaning of the stability domain were analysed through numerical simulation calculations. Finally, the correctness of the analysis conclusion was verified through experiments on the two-body aircraft, accumulating the technical foundation for subsequent research on high-altitude deployment.

Coarctation of the aorta is characterised by narrowing of the descending aorta and is a rare cause of secondary hypertension in children and young adults. The aortic stenosis lesion is in a special location with severe consequences, and long-term survival is very low, with high rates of disability and mortality, and can be challenging to detect due to its few clinical manifestations. We report a case of a young patient with atrial fibrillation, renal infarction, and acute cerebral infarction, which are consequences of untreated hypertension due to coarctation of the aorta. The purpose of this report is to emphasize the importance of early diagnosis and management of coarctation of the aorta as a cause of secondary hypertension in children and young adults.