A recent study published in Oryx proposed that the extinct Javan tiger Panthera tigris sondaica may still survive on the Island of Java, Indonesia, based on mitochondrial DNA analysis of a single hair sample collected from a location where a tiger was reportedly encountered. However, upon reanalysing the genetic data presented in that study, we conclude that there is little support for this claim. The sequences of the putative tiger hair and Javan tiger museum specimens generated are not from tiger cytoplasmic mitochondrial DNA but more likely the nuclear pseudogene copies of mitochondrial DNA. In addition, the number of mismatches between the two Javan tiger sequences is unusually high for homologous sequences that are both from tigers, suggesting potential issues with data reliability. The paper provides insufficient details on quality control measures, making it impossible to rule out the possibility that errors were introduced during the analysis. Consequently, it is inappropriate to use the sequences presented in that study to infer the existence of the Javan tiger.

Understanding the solutal convection is a crucial step towards accurate prediction of CO$_2$ sequestration in deep saline aquifers. In this study, pore-scale resolved direct numerical simulations (DNS) are performed to analyse the scaling laws of the solutal convection in porous media. The porous media studied are composed of uniformly distributed square or circular elements. The Rayleigh numbers in the range $426 \le Ra \le 80\,000$, the Darcy numbers in the range $1.7\times 10^{-8} \le Da \le 8.8\times 10^{-6}$ and the Schmidt numbers in the range $250 \le Sc \le 10^4$ are considered in the DNS. The main time, length and velocity scales affecting the solutal convection are classified as the diffusive scales ($t_I$, $l_I$ and $u_I$), the convective scales ($t_{II}$, $l_{II}$ and $u_{II}$) and the shut-down scales ($t_{III}$, $l_{III}$ and $u_{III}$). These scales determine the pore-scale Rayleigh number $Ra_K$ and the Rayleigh number $Ra$. Based on the DNS results, the scaling laws for the transient dissolution flux are proposed in the different regimes of convection. It is found that the onset time of convection ($t_{oc}$) and the period of the flux-growth regime ($\Delta t_{fg}$) vary linearly with the convective time scale $t_{II}$. The merging of the original plumes and the re-initiation of the new plumes start in the same period, resulting in the merging re-initiation regime. Horizontal dispersion plays an important role in plume merging. The dissolution flux $F$ and the time since the onset of convection $t^{\ast }$ have an $F / u_{II} \sim (t^{\ast }/ t_{II})^{-0.2}$ scaling in the later stage of the merging re-initiation regime. This scaling is caused by the merging of the low-wavenumber plumes. It becomes more pronounced with decreasing porosity and leads to the nonlinear relationship between the Sherwood number $Sh$ and $Ra$ when the domain is not high enough for the plumes to fully develop. According to the DNS results, a regime is expected that is independent of both $Ra$ and $Ra_K$, while the dimensionless constant flux $F_{cf}/u_{II}$ in this regime decreases with decreasing porosity. When the mean solute concentration reaches approximately 30 %, convection enters the shut-down regime. For large $Ra$, the dimensionless flux in the shut-down regime follows the scaling law $F/u_{III}\sim (t/t_{III})^{-1.2}$ at large porosity ($\phi =0.56$) and $F/u_{III}\sim (t/t_{III})^{-1.5}$ at small porosity ($\phi =0.36$ or $0.32$). The study shows the significant pore-scale effect on the convection. The DNS cases in this study are mainly for simplified geometries and large $Ra_K$. This can lead to uncertainties of the obtained scaling coefficients. It is important to determine the scaling coefficients for real geological formations to predict a real CO$_2$ sequestration process.

The flow-induced vibrations (FIVs) of two identical tandem square cylinders with mass ratio m* = 3.5 at Reynolds number Re = 150 are investigated through two-dimensional direct numerical simulation (DNS) and linear stability analysis over a parameter range of spacing ratio 1.5 ≤ L* ≤ 5 and reduced velocity 3 ≤ Ur ≤ 34. Three kinds of FIV responses, namely vortex-induced vibration (VIV), biased oscillation (BO) and galloping (GA), are identified. The FIVs are then further classified into the branches of initial VIV (IV), resonant VIV (RV and RV′), flutter-induced VIV (FV), desynchronized VIV (DV), VIV developing from GA (GV), transitional state between VIV and GA (TR), BO and GA based on the characteristics of the vibration responses. The transitions among different FIV branches are examined by combining the DNS with linear stability analysis, where the transition boundaries among the VIV, BO and GA branches over the concerned parameters are identified on the branch maps. The transition from IV to RV or RV′ is found to be related to the unstable wake mode, while the FV, transiting from RV or RV′, is induced by the unstable structural factor in the wake-structure mode. The structural instability is considered as the physical origin of GA, whereas the mode competition between unstable wake and structure leads to DV, GV and TR, and thus delays the appearance of GA. The transition from DV to BO with biased equilibrium position, accompanied by the even-order harmonic frequencies, is essentially induced by the symmetry breaking bifurcation.

This study presents a dual-channel vortex generator (VG) that leverages the snap-through behaviour of flexible sheets. The VG outperforms a similar-sized rigid VG in generating vortices within dual-channel flows while minimizing pressure loss. Numerical simulations using the immersed boundary-lattice Boltzmann method analyse the dynamics and vortex generation performance of the sheet under various system parameters. Two distinct modes are identified for the elastic sheet: a sustained snap-through mode (SSTM) and a dormant mode (DM). The sheet's mode is predominantly influenced by its length ratio (L*), bending stiffness $(K_b^\ast )$ and flow strength, with the mass ratio having a minimal impact. The sheet exhibiting regular SSTM can effectively generate vortices in both channels and the vortex generation performance can be conveniently tuned by altering the sheet's initial buckling (i.e. L*). An increase in $K_b^\ast $ results in a higher critical Reynolds number (Rec) required for mode transition. An increase in L*, however, initially raises Rec and then lowers it, suggesting an optimal length ratio (approximately 0.7 for our considered system) for minimizing the Rec necessary to trigger SSTM. Furthermore, a disparity in the flow strength between channels is found to suppress the snap-through of the sheet; a greater disparity, however, is permissible to induce the SSTM of more compliant sheets. These findings underscore the potential of snap-through behaviour for enhanced flow manipulation in dual-channel systems.

Stray light from the sun is one of the most significant factors affecting image quality for the optical system of a spacecraft. This paper proposes a method to design a deployable supporting mechanism for the sunshield based on origami. Firstly, a new type of space mechanism with single-closed loop was proposed according to thick-panel origami, and its mobility was analysed by using the screw theory. In order to design a deployable structure with high controllability, the tetrahedral constraint was introduced to reduce the degree of freedom (DOF), and a corresponding deployable unit named tetrahedral deployable unit (TDU) was obtained. Secondly, the process to constructing a large space deployable mechanism with infinite number of units was explained based on the characteristics of motion and planar mosaic array, and kinematics analysis and folding ratio of supporting mechanism were conducted. A physical prototype was constructed to demonstrate the mobility and deployment of the supporting mechanism. Finally, based on the Lagrange method, a dynamic model of supporting mechanism was established, and the influence of the torsion spring parameters on the deployment process was analysed.

In the present study, acid-modified attapulgite was used, as an adsorbent, to remove as much Cd2+ as possible from aqueous solution. Static adsorption experiments using powdered acid-modified attapulgite, and dynamic adsorption using granular acid-modifed attapulgite, were conducted to explore the practical application of modified attapulgite in the adsorption of Cd2+. The modified attapulgite had a larger specific surface area and thinner fibrous crystals than the unmodified version. No obvious differences were noted, in terms of the crystal structure, between the natural attapulgite and the modified version. The effects of initial concentration, pH, contact time, and ionic strength on the adsorption of Cd2+ were investigated, and the results showed that the adsorption capacity of the modified attapulgite was increased with increasing pH and the initial Cd2+ concentration. The adsorption properties were analyzed by means of dynamic adsorption tests with respect to various Cd2+ concentrations and flow rates. The maximum adsorption capacity of 8.83 mg/g occurred at a flow rate of 1 mL/min and at an initial concentration of 75 mg/L. Because there was better accord between the data and a pseudo-second order model than a pseudo-first-order model, external mass transfer is suggested to be the rate-controlling process. The experimental data were also fitted for the intraparticle diffusion model, implying that the intraparticle diffusion of Cd2+ onto the modified attapulgite was also important for controlling the adsorption process. The Bohart-Adams model was more suitable than the Thomas model for describing the dynamic behavior with respect to the flow rate and the initial Cd2+ concentration. This research provided the theoretical basis for the dynamic adsorption of Cd2+ on the modified attapulgite. Compared to the powdered modified attapulgite, the dynamic adsorption by granular modified attapulgite appeared more favorable in terms of practical application.

A rhamnolipid-layered double hydroxide (RL-LDH) nanocomposite, derived from the rhamnolipid (RL) biosurfactant, was synthesized through a delamination/reassembling process. The adsorption characteristics of Cu(II) on RL-LDH were investigated in detail and the results indicated the potential of using RL-LDH as an environmentally friendly adsorbent to remove Cu(II). The fabricated RL-LDH nanocomposite was characterized using powder X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, elemental chemical composition, and specific surface area analyses. Batch adsorption experiments were conducted to study the influence of various factors, such as contact time, initial Cu(II) concentration, temperature, initial solution pH, and electrolyte concentration on Cu(II) adsorption by the RL-LDH nanocomposite. The RL-LDH nanocomposite had a low surface area of 11.71 m2 g−1, which suggests that surface adsorption would not be important in Cu(II) adsorption. The Cu(II) adsorption data fitted the Freundlich model well at pH 5.5, whereas the adsorption kinetics were accurately described by a pseudo-second-order kinetics model. Chemical binding, that is, the formation of a RL-Cu(II) complex in the LDH interlayer, was assumed to be the rate-limiting step in the adsorption process. Thermodynamic parameters that included Gibbs free energy, enthalpy, and entropy changes were also calculated. The adsorption was found to be a spontaneous and exothermic chemisorption process. Furthermore, the adsorption properties of RL-LDH for Cu(II) were compared to Cu(II) adsorption using other adsorbents.

Supersonic gas jets generated via a conical nozzle are widely applied in the laser wakefield acceleration of electrons. The stability of the gas jet is critical to the electron injection and the reproducibility of the wakefield acceleration. Here we discussed the role of the stilling chamber in a modified converging–diverging nozzle to dissipate the turbulence and to stabilize the gas jets. By the fluid dynamics simulations and the Mach–Zehnder interferometer measurements, the instability originating from the nonlinear turbulence is studied and the mechanism to suppress the instability is proposed. Both the numerical and experimental results prove that the carefully designed nozzle with a stilling chamber is able to reduce the perturbation by more than 10% compared with a simple-conical nozzle.

Before the Omicron variant ran amok inside China in November 2022, the Chinese central government’s dynamic zero-COVID policy effectively contained the spread of the coronavirus and its variants during multiple waves of outbreaks. However, it was not without cost. This study examines the impacts of stringent lockdown interventions on urban residents’ mental health during the initial outbreak of the Omicron variant in the spring of 2022. Using survey data from 522 respondents within the same neighbourhood and a spatial quasi-experimental design, the results show that strict lockdown interventions are significantly related to higher levels of psychological distress after controlling for observed confounders and that lockdown interventions have further spillover effects on mental health for residents in adjacent residential compounds who are otherwise free. Moreover, the results show that the lack of material supplies and medical care plays a more salient role in explaining lockdown effects on psychological distress than residents’ social interaction and trust levels of COVID-19 policy. Policy and intervention implications are also discussed.

Coastal eutrophication and hypoxia remain a persistent environmental crisis despite the great efforts to reduce nutrient loading and mitigate associated environmental damages. Symptoms of this crisis have appeared to spread rapidly, reaching developing countries in Asia with emergences in Southern America and Africa. The pace of changes and the underlying drivers remain not so clear. To address the gap, we review the up-to-date status and mechanisms of eutrophication and hypoxia in global coastal oceans, upon which we examine the trajectories of changes over the 40 years or longer in six model coastal systems with varying socio-economic development statuses and different levels and histories of eutrophication. Although these coastal systems share common features of eutrophication, site-specific characteristics are also substantial, depending on the regional environmental setting and level of social-economic development along with policy implementation and management. Nevertheless, ecosystem recovery generally needs greater reduction in pressures compared to that initiated degradation and becomes less feasible to achieve past norms with a longer time anthropogenic pressures on the ecosystems. While the qualitative causality between drivers and consequences is well established, quantitative attribution of these drivers to eutrophication and hypoxia remains difficult especially when we consider the social economic drivers because the changes in coastal ecosystems are subject to multiple influences and the cause–effect relationship is often non-linear. Such relationships are further complicated by climate changes that have been accelerating over the past few decades. The knowledge gaps that limit our quantitative and mechanistic understanding of the human-coastal ocean nexus are identified, which is essential for science-based policy making. Recognizing lessons from past management practices, we advocate for a better, more efficient indexing system of coastal eutrophication and an advanced regional earth system modeling framework with optimal modules of human dimensions to facilitate the development and evaluation of effective policy and restoration actions.

Visitors to zoos are a source of potential stress to certain captive-housed animals. Much research has focused on Europe and America, whereas the effect of human audiences on the behaviour of captive animals in Chinese parks has so far not been investigated. Sika deer (Cervus nippon) housed in Zhu-Yu-Wan Park, Yangzhou City, Jiangsu Province, China, were studied to determine the effect of different visitor density levels on the animals’ activity. From June 21 to December 10, 2006, and again from February 21 to July 10, 2007, 21 subjects were observed for 10 h per week for a total of 44 weeks. Continuous focal animal sampling was used to quantify behaviours, and visitor density was recorded every minute. Friedman's tests were used to examine the effects of visitor density on the behaviour of sika deer. Results showed that high visitor density was significantly related to foraging, resting, watching and ‘non-visible’ behaviours. The findings demonstrate that high numbers of visitors have an effect on the welfare of sika deer.

We report VLBI monitoring observations of the 22 GHz H2O masers toward the Mira variable BX Cam. Data from 37 epochs spanning ∼3 stellar pulsation periods were obtained between May 2018 and June 2021 with a time interval of 3–4 weeks. In particular, the VERA dual-beam system was used to measure the kinematics and parallaxes of the H2O maser features. The obtained parallax, 1.79±0.08 mas, is consistent with Gaia EDR3 and previous VLBI measurements. The position of the central star was estimated relied on Gaia EDR3 data and the center position of the 43 GHz SiO maser ring imaged with KVN. Analysis of the 3D maser kinematics revealed an expanding circumstellar envelope with a velocity of 13±4 km s−1 and significant spatial and velocity asymmetries. The H2O maser animation achieved by our dense monitoring program manifests the propagation of shock waves in the circumstellar envelope of BX Cam.

High-molecular-weight glutenin subunits (HMW-GS) contribute to dough elasticity and bread baking quality in wheat. In this study, wheat varieties were classified based on their HMW-GS composition into three groups: 1Dx5 (5 + 10, Gaoyou 8901, Xinmai 28, Xinmai 19, Xinmai 26 and Jinbaoyin), 1Dx2 (2 + 12, Zhoumai 24, Xinmai 9 and Yumai) and 1Dx4 (4 + 12, Aikang 58). Sequence analysis showed that 1Dx-GY8901, 1Dx-XM28, 1Dx-XM19 and 1Dx-XM26 were similar to the 1Dx5 gene and clustered on the same branch, while 1Dx-AK58, 1Dx-ZM24, 1Dx-JBY, 1Dx-YM, 1Dx-XM9 and 1Dx-JBY were more similar to the 1Dx2 gene and clustered on the same branch with 1Dx.2.2. There was a mutation of Ser to Cys at position S2, for an extra Cys in the repeat regions of 1Dx-XM19, 1Dx-XM26, 1Dx-XM28 and 1Dx-GY8901. The wheat HMW-GS genes exhibited similar percentages of α-helix, extended strand, β-turn and random coil structure, with ranges of 13.33–13.59, 4.77–5.78, 7.08–9.18 and 72.3–73.94%, respectively. Sequence conservation and the composition of HMW-GS subunits were also analysed for a series of strong gluten wheat varieties, Xinmai 9 (1, 7 + 8, 2 + 12), Xinmai 19 (1, 7 + 9, 5 + 10), Xinmai 26 (1, 7 + 8, 5 + 10) and Xinmai 28 (1, 7 + 9, 5 + 10). The results of this work should facilitate future breeding efforts and provide the theoretical basis for wheat quality improvement.

Microtubule-severing proteins (MTSPs) play important roles in mitosis and interphase. However, to the best of our knowledge, no previous studies have evaluated the role of MTSPs in female meiosis in mammals. It was found that FIGNL1, a member of MTSPs, was predominantly expressed in mouse oocytes and distributed at the spindle poles during meiosis in the present study. FIGNL1 was co-localized and interacted with γ-tubulin, an important component of the microtubule tissue centre (MTOC). Fignl1 knockdown by specific small interfering RNA caused spindle defects characterized by an abnormal length:width ratio and decreased microtubule density, which consequently led to aberrant chromosome arrangement, oocyte maturation and fertilization obstacles. In conclusion, the present results suggested that FIGNL1 may be an essential factor in oocyte maturation by influencing the meiosis process via the formation of spindles.

Recently, Gross, Mansour and Tucker introduced the partial-dual polynomial of a ribbon graph as a generating function that enumerates all partial duals of the ribbon graph by Euler genus. It is analogous to the extensively studied polynomial in topological graph theory that enumerates by Euler genus all embeddings of a given graph. To investigate the partial-dual polynomial, one only needs to focus on bouquets: that is, ribbon graphs with exactly one vertex. In this paper, we shall further show that the partial-dual polynomial of a bouquet essentially depends on the signed intersection graph of the bouquet rather than on the bouquet itself. That is to say, two bouquets with the same signed intersection graph have the same partial-dual polynomial. We then give a characterisation of when a bouquet has a planar partial dual in terms of its signed intersection graph. Finally, we consider a conjecture posed by Gross, Mansour and Tucker that there is no orientable ribbon graph whose partial-dual polynomial has only one nonconstant term; this conjecture is false, and we give a characterisation of when all partial duals of a bouquet have the same Euler genus.

Access to vast datasets of visual and textual materials has become significantly easier. How to take advantage of the conveniently available data to support creative design activities remains a challenge. In the phase of idea generation, the visual analogy is considered an effective strategy to stimulate designers to create innovative ideas. Designers can read useful information off vague and incomplete conceptual visual representations, or stimuli, to reach potential visual analogies. In this paper, a computational framework is proposed to search and retrieve visual stimulation cues, which is expected to have the potential to help designers generate more creative ideas by avoiding visual fixation. The research problems include identifying and detecting visual similarities between visual representations from various categories and quantitatifying the visual similarity measures serving as a distance metric for visual stimuli search and retrieval. A deep neural network model is developed to learn a latent space that can discover visual relationships between multiple categories of sketches. In addition, a top cluster detection-based method is proposed to quantify visual similarity based on the overlapped magnitude in the latent space and then effectively rank categories. The QuickDraw sketch dataset is applied as a backend for evaluating the functionality of our proposed framework. Beyond visual stimuli retrieval, this research opens up new opportunities for utilizing extensively available visual data as creative materials to benefit design-by-analogy.