We report an experimental investigation of turbulent Rayleigh–Bénard convection in a quasi-two-dimensional rectangular cell of large aspect ratio ($\varGamma = 10$) over the Rayleigh number range $5.4\times 10^7 \leqslant Ra \leqslant 7.2\times 10^9$ and Prandtl number range $4.3 \leqslant \textit{Pr} \leqslant 67.3$. Planar particle image velocimetry measurements show that the flow self-organises into several horizontally aligned convection rolls, and repeated experiments under identical parameters (both $Ra$ and $\textit{Pr}$) reveal that the number of rolls varies within the range of 3–7 with 6 being the most probable, which demonstrates the presence of multiple flow states. When $\textit{Pr}$ is increased to 67.3, the number of roll-like structures increases significantly, indicating a structural transition from a roll-dominated to a plume-dominated flow. This transition is reflected in the global momentum transport, for $\textit{Pr} \leqslant 18.3$, the Reynolds number scales as $\textit{Re} \sim Ra^{0.58}\textit{Pr}^{-0.97}$, whereas the scaling is changed to $\textit{Re} \sim Ra^{0.72}$ when $\textit{Pr}$ reaches 67.3. Within individual rolls, we further examine the Reynolds numbers based on horizontal and vertical velocity components, $\textit{Re}_{u,\textit{roll}}$ and $\textit{Re}_{w,\textit{roll}}$, and find that the former increases while the latter decreases with roll size (quantified as the aspect ratio of the roll $\varGamma _{\textit{roll}}$) due to continuity constraints, with their ratio following $\textit{Re}_{w,\textit{roll}}/\textit{Re}_{u,\textit{roll}} \sim \varGamma _{\textit{roll}}^{-0.61}$. We impose different initial flow conditions (roll structures) with controlled perturbations and demonstrate that the initial condition can influence the final turbulent state. We show that the number of horizontally aligned rolls regulates the global transport: a larger number of rolls induces greater vertical momentum and heat transfer. Our study provides the first systematic experimental evidence of multiple flow states in large aspect ratio turbulent Rayleigh–Bénard convection and clarify how these states influence global transport.

Cinara cedri is an economically important pest infesting cedars. This study presents the first study of its cold tolerance, providing key parameters for assessing its climatic adaptability and potential invasion risks. The supercooling points (SCPs) of eggs, adults, and first-instar nymphs (hereafter nymphs) were determined, along with lethal low temperatures, and the effects of cold acclimation (ACC) and rapid cold hardening (RCH) on cold tolerance. Results showed that eggs exhibited the strongest supercooling capacity, with a mean SCP of −30.14°C, significantly lower than that of adults (−12.89°C) and nymphs (−14.21°C). Under constant laboratory conditions, active aphids suffered no significant mortality at −5°C, whereas exposure to −7°C and −10°C for 1 and 2 h resulted in substantially higher mortality in nymphs than in adults. The 1– and 2–h lethal temperatures for 50% mortality (LT50) were estimated as −10.28°C and −9.06°C for adults, and −8.00°C and −6.87°C for nymphs, respectively. Both ACC and RCH effectively enhanced cold tolerance; adults and nymphs exhibited markedly stronger cold hardiness in December relative to May, and exposure to 3°C for 2 h significantly reduced adult mortality. Collectively, these results establish an empirical foundation for forecasting population responses to short-term extreme low-temperature events and contribute to understanding the low-temperature biology of this aphid.

Microplastic (MP) pollution in terrestrial ecosystems is attracting global attention. The transfer of MPs in terrestrial food chains remains poorly understood, particularly in poultry systems. This study investigates polystyrene (PS) MP transfer and surface weathering characteristics in an “earthworm-chicken” food chain by feeding chickens earthworms that had been previously exposed to PS MPs and by oral gavage. The results showed that MP concentrations decreased from soil (10.06 ± 0.03 mg/g) to earthworm casts (6.39 ± 1.05 mg/g) to chicken faeces (3.76 ± 0.39 mg/g), and the transfer process of MPs in the “earthworm-chicken” food chains is characterized by continuous fragmentation. MPs were distributed throughout different parts of the chickens’ digestive tract after 3 h oral gavage and were only detected in the faeces after 24 h. Scanning electron microscopy and Fourier transform infrared spectroscopy revealed that MPs underwent varying degrees of weathering in the earthworm casts, chicken faeces and gastrointestinal tract, exhibiting surface holes and cracks. Compared with pristine MPs, the significantly higher carbonyl index of MPs in the gizzard demonstrates the key role of the gizzard in MP fragmentation. This study contributes to understanding the trophic transfer and fragmentation processes of MPs in chickens, and provides a basis for future research on the environmental processes of MPs in terrestrial food chains.

We present the design, construction and initial experimental validation of the Northwestern Polytechnical University Taylor–Couette (NPU-TC) apparatus, specifically developed to explore turbulent Taylor–Couette flows under conditions relevant to ultra-high-speed rotating machinery. The apparatus features an inner cylinder capable of rotating at speed of up to 10 000 rpm, corresponding to a Taylor number $Ta = 6.4 \times 10^8$, with an exceptionally narrow annular gap of 2.8 mm, yielding a radius ratio ($\eta$) of 0.98. Axial-scanning particle image velocimetry is employed here for the first time in air-based TC flows at such extreme conditions, which enables detailed velocity measurements without intrusive disturbances. Our velocity measurements demonstrate the absence of large-scale coherent flow structures, indicating a transition into the ultimate turbulence regime characterised by very thin boundary layers and nearly uniform velocity distributions in the bulk region. The NPU–TC apparatus thus represents a significant advance in experimental capabilities, providing critical insights into turbulent flow behaviour in high-speed rotating machinery.

We perform numerical simulations of forced homogeneous isotropic turbulence over a range of bulk viscosities, Reynolds numbers and Mach numbers to investigate the scaling of key flow statistics. Using the Helmholtz decomposition, we analyse the scalings of Favre-averaged turbulent kinetic energy (TKE), root-mean-square (r.m.s.) pressure, pressure dilatation, dilatational dissipation and higher-order velocity-gradient moments. Additionally, new models are proposed for the pressure-dilatation term and the bulk-viscosity dependence of dilatational dissipation. Although the solenoidal and dilatational components of the Favre-averaged TKE are not strictly orthogonal, our numerical results demonstrate that their ratio is well approximated by the squared ratio of the corresponding r.m.s. velocities. The r.m.s. pressure approaches the pseudo-sound scaling as bulk viscosity increases. Within the Donzis r.m.s. pressure model (Donzis & John 2020 Phys. Rev. Fluids 5(8), 084609), we find that the solenoidal contribution becomes dominant for large bulk viscosity. Pressure dilatation is found to depart systematically from pseudo-sound predictions: without bulk viscosity it favours transfer from kinetic to internal energy, while finite bulk viscosity can reverse this transfer at high Mach numbers. The scaling exponent of dilatational dissipation is shown to vary with bulk viscosity, enabling a corrected model for its exponent and prefactor. Velocity-gradient skewness and flatness reveal that the onset of shocklet-induced divergence is delayed with increasing bulk viscosity and may be suppressed entirely. The results extend recent velocity-ratio-based scaling frameworks and provide modelling insights into compressible turbulence.

Ferrisia dasylirii (Cockerell) (Hemiptera: Coccomorpha: Pseudococcidae) is a polyphagous mealybug species and native to North America, but has spread to Asia and Africa. In this study, we report F. dasylirii for the first time from China using an integrated taxonomy approach combining morphological characters and molecular analyses of the mitochondrial cytochrome oxidase subunit 1 gene. It was found on 12 tropical fruit species in Hainan Province: Annonaceae: Annona squamosa L. and A. squamosa ‘Purple’; Myrtaceae: Eugenia brasiliensis Lam. and Psidium guajava L.; Malvaceae: Theobroma cacao Linn.; Lecythidaceae: Lecythis pisonis Cambess.; Sapotaceae: Pouteria campechiana (Kunth) Baehni and P. sapota (Jacq.) H.E.Moore & Stearn; Rubiaceae: Coffea liberica W. Bull ex Hiern; Cunoniaceae: Davidsonia pruriens F. Muell; Arecaceae: Areca catechu Linn.; Musaceae: Musa nana Lour.; Malpighiaceae: Malpighia emarginata Sesse & Noc.ex DC.; and Phyllanthaceae: Phyllanthus emblica Linn. This record increases the known geographic range of F. dasylirii and underscores the importance of combined morphological and molecular approaches for accurate mealybug identification.

The present study establishes a general theory for fluid-element rotation and intrinsic vorticity decompositions within the framework of vorticity kinematics. We propose two direction-dependent vorticity decompositions (DVDs) based on the analysis of rotation of directed material line and surface elements, with the rigid-rotation and spin modes of vorticity being explicitly defined. Intrinsic coupling relations are then derived for a pair of orthogonal line and surface elements, demonstrating their complementary roles in both kinematics and geometry. Notably, the surface-element-based spin mode is shown to coincide with the relative vorticity in the generalized Caswell formula, thereby providing a faithful representation of surface shear stress in Newtonian fluids. Correspondingly, another two DVDs are constructed based on the geometry of streamlines and streamsurfaces in the field description. Furthermore, within the characteristic algebraic description, in terms of the rotational invariants $(\psi ,\gamma )$ in the real Schur form of the velocity gradient tensor, two invariant vorticity decompositions (IVDs) are formulated. The first IVD with positive spin aligns with the Liutex-shear decomposition, which corresponds to the Klein–Kaden–Betz (KKB) mechanism by which wrapping shear layers form axial vortices. The second IVD is indispensable for understanding unidirectional swirling motion around a point on the rotation-axis-normal plane ${\mathcal{P}}$, corresponding to an anti-KKB mechanism/phenomenon characterized by the negative spin. Importantly, it is proved that the DVD vorticity modes are rigorously bounded by the IVD vorticity modes $(R_{N}^{\pm },s_{N}^{\pm })=(2\psi ^{\pm },\gamma ^{\pm })$ on ${\mathcal{P}}$. Finally, distinctive features and applicability of these kinematic tools are demonstrated with representative examples. The results indicate that a coupled IVD–DVD approach provides a powerful diagnostic tool for unravelling the subtle structures and fundamental physics inherent to complex flow fields.

Host plant adaptability drives the ecological plasticity and global expansion of Spodoptera frugiperda (J.E. Smith, 1797). However, the mechanisms underlying the long-term adaptation of its maize ecotype to alternative hosts remain unclear, hindering host-shift risk predictions. We evaluated the host-shift risk of the maize ecotype of S. frugiperda across four generations of continuous rearing on maize (Zea mays L.), wheat (Triticum aestivum L.), rice (Oryza sativa L.), and green bristlegrass (Setaria viridis (L.) P. Beauv.) by analyzing biological performance, feeding and oviposition behaviours feeding/oviposition preferences, and protective enzyme dynamics. Prolonged monophagous feeding significantly accelerated developmental cycles across generations. Wheat emerged as the most suitable host under laboratory conditions, shortening immature stages to 22.86 d (F3) and increasing pupal weight by 40.7%, whereas S. viridis resulted in the lowest fitness, with 32.31-d immature period and 59.33% survival rate (F4). Larval feeding and adult oviposition preferences consistently aligned with multigenerational feeding on the same host. Enzymatic profiling showed maize-fed larvae maintained the lowest catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD), whereas S. viridis-reared larvae exhibited peak enzyme activities. Notably, adaptation to wheat was associated with reduced enzymatic stress responses, with CAT and POD activities decreasing by 21.8% and 17.5%, respectively, from F1 to F3, indicating physiological acclimation. These findings suggest that multigenerational feeding can enhance population fitness and promote host preference through physiological and behavioural plasticity. This laboratory study indicates the potential for the maize ecotype to pose threat to wheat production, providing a basis for managing.

Laser-driven plasma wakefield acceleration (LWFA) offers exceptionally high acceleration gradients and can produce high-brightness electron beams. However, the laser-to-electron energy conversion efficiency typically remains limited to a few percent. Theoretically, the self-mode transition from LWFA to beam-driven plasma wakefield acceleration (PWFA) provides a pathway for fully utilizing the laser energy. Here, we demonstrate the single-stage LPWFA (hybrid LWFA–PWFA) scheme, validated through comparative experiments using a 300 TW tightly focused laser interacting with sub-critical density nitrogen gas targets. The experiments produce an electron beam with charge of approximately 31 nC above 6 MeV and approximately 116 nC above 2 MeV. The laser-to-electron energy conversion efficiency is approximately 6.1% (>6 MeV) and 16.4% (>2 MeV), respectively. Particle-in-cell simulations confirm that the single-stage LPWFA mechanism depletes the laser energy and enables continual electron injection. This high-charge, multi-MeV electron beam has great value in the generation of high-brightness $\unicode{x3b3}$-rays and high-flux neutron sources.

The current study was designed to examine the association between a composite healthy lifestyle score (HLS) and thyroid function biomarkers among American adults. This cross-sectional study utilised data from 5693 adults aged ≥ 18 years in the National Health and Nutrition Examination Survey 2007–2012 cycles. A HLS (range 0–6) was constructed based on six modifiable factors: non-smoking, no heavy alcohol intake, normal BMI (18·5–24·9 kg/m2), high physical activity (upper tertile of metabolic equivalent-min/week), adequate sleep (7–9 h/night) and appropriate energy intake. Serum concentrations of thyroid-stimulating hormone, free and total thyroxine (FT4, TT4), free and total triiodothyronine (FT3, TT3), thyroglobulin (Tg) and thyroid antibodies (TPOAb, TgAb) were measured. Multivariable linear regression adjusted for sociodemographic factors was used to assess associations. In fully adjusted models, each one-point increase in HLS was associated with lower serum FT4 (β = –0·07 ng/dl; 95 % CI: –0·10, –0·03; P < 0·001) and TT4 (β = –0·11 µg/dl; 95 % CI: –0·15, –0·06; P < 0·001). Compared with participants with an HLS of 0–1, those with HLS 4–6 had lower FT4 (β = –0·20; 95 % CI: –0·30, –0·09; P < 0·001) and TT4 (β = –0·36; 95 % CI: –0·49, –0·22; P < 0·001). Associations for other thyroid markers were not statistically significant after correction for multiple comparisons (P > 0·05). A healthier lifestyle is inversely associated with serum FT4 and TT4 levels, highlighting potential links between modifiable behaviours and thyroid physiology.

The unanticipated spillover effects of economic policies on residents’ political trust have seldom been discussed in the literature. This paper examines the impact of the rapid increase in housing prices, triggered by the economic stimulus policies implemented by the Chinese government in response to the 2008 financial crisis, on residents’ political trust. Empirical research based on data from the China Family Panel Studies (CFPS) indicates that the rapid rise in housing prices had differentiated effects on political trust among different age groups: it weakened the political trust of the younger and middle-aged groups but enhanced the political trust felt by elderly groups. Mechanism analysis reveals that the sudden and rapid rise in housing prices exacerbated younger people’s housing difficulties, suppressed their wealth accumulation and undermined their sense of self-efficacy, thus eroding their political trust. The findings of this paper not only extend the research on the formation mechanism of political trust but also broaden the research perspective of housing politics and provide new empirical evidence for understanding the complex dynamic relationship between economic development and political stability.

Near-space hypersonic vehicles encounter significant rarefaction effects during the flight through the atmosphere, causing the classical Navier–Stokes–Fourier (NSF) equations to break down and posing challenges for the evaluation of surface drag and heat flux. In this paper, the nonlinear momentum and heat transfer in a hypersonic transitional boundary layer are analysed based on the generalized hydrodynamic equations (GHE), and the generality of the derived formulae is also discussed. The leading transport relations are obtained by estimating the relative orders of the various terms in GHE according to the hypersonic flow and boundary-layer requirements. Local non-equilibrium parameters characterising the shear non-equilibrium effect ($K_\sigma$) and thermal-gradient non-equilibrium effect ($K_q$) are introduced, and a set of correlation formulae for local surface pressure, shear stress and heat flux are proposed as corrections to continuum-based solutions. The correction function depends only on the non-equilibrium parameters $K_\sigma$ and $K_q$, and the continuous solutions can be either analytical formulae or NSF simulation results. This enables us to predict the surface aerothermodynamics with enhanced accuracy while still using the solutions of the NSF equations. The proposed formulae are carefully verified by comparing with direct simulation Monte Carlo (DSMC) results of different hypersonic rarefied flows, including flat-plate, sharp-wedge, cylinder and blunt-cone flows, and partial experimental data are also given. The results demonstrate that the proposed formulae can significantly enhance the accuracy of the continuum-based solutions, and show good agreement with DSMC simulations and experimental measurements in the near-continuum regime.

Despite Taiwan’s exclusion from many treaty regimes, Taiwan’s Constitutional Court (TCC) has at times cited international law, particularly international human rights norms. To analyse the authority and influence of these citations, this article proposes a typology along two dimensions: legal effect (whether the Court treats international norms as legally binding or merely advisory) and impact level (whether international norms are used to reaffirm or alter existing constitutional jurisprudence, or to guide future developments). Applying this framework reveals that the TCC’s traditional tendency to treat international norms as non-binding and reaffirming is evolving. In recent years, the TCC has increasingly invoked international law to articulate new rights protections and has begun to recognise its legal authority, suggesting a deeper engagement. Beyond the case study of Taiwan, this typology offers an analytical tool for distinguishing varying degrees of judicial engagement with international law and for underscoring the evolving nature of such engagement.

We numerically investigate the cellular detonation dynamics in ethylene/oxygen/ozone/nitrogen mixtures considering detailed chemical kinetics. The aim is to elucidate emergent detonation structures and reveal the transition mechanism from single- to double-cellular structures. Ozone is used to induce two-stage reactions within the mixture. Through systematic initiation strength analysis, we demonstrate two distinct propagation regimes: (i) under strong initiation, a stable double-cellular detonation is established; (ii) weak initiation triggers a multi-stage evolutionary process, beginning with a low-speed single-cellular detonation in the initiation zone. During the initial weak stage, the detonation propagates at a quasi-steady velocity with uniform cellular patterning. The subsequent transition phase features spontaneous acceleration accompanied by structural bifurcation into double cells, ultimately stabilising in a normal stage with sustained double-cellular structures. Further analysis reveals that the weak-stage dynamics is governed exclusively by first-stage chemical reactions, resulting in a single-cellular structure propagating at a velocity much lower than the Chapman–Jouguet speed. In contrast, the double-cellular structure observed at the normal stage results from the two-stage exothermic reactions. Thermodynamic perturbations arising from cellular instability and fluid dynamic instability are identified as critical drivers for the transition from single- to double-cellular detonation. Besides, conditions for the formation of double-cellular detonation are explored, and two qualitative requirements are summarised: the reactions of the two stages must proceed as independently as possible, and both heat releases from the two stages must be high enough to sustain the triple-shock configurations.