Phytoplasmas are phloem-limited bacteria that are primarily transmitted by hemipteran insects and are emerging threats to Camptotheca acuminata Decne plants due to their associations with a witches’ broom disease. Despite numerous studies, there has been no report on insect transmission of phytoplasma among C. acuminata. Here, transmission characteristics of the leafhopper, Empoasca paraparvipenis Zhang and Liu, 2008 and the phytoplasma in plant leaves through PCR quantification are described. The interaction between C. acuminata-phytoplasma and insect vectors was examined by analysing the impact on the life characteristics and progeny population in a temperature-dependent manner. Phytoplasma-infected C. acuminata plant exhibited symptoms including shorter internodes, weak and clustered branches, shrunken and yellowed leaves, and red leaf margins. The acquisition and transmission time of bacterial-infected third-instar nymphs of insect vectors were 10 (11.11%) and 30 min (33.33%), respectively. A single insect vector can infect a plant after 72 h of feeding, and the incidence rate of disease increases with the number of insects following 11–100% from single to 20 insects. The development time of the infected insect vectors (1–3 instars) was significantly shorter than that of the healthy insects, and the development duration of instar individuals was longer. In progeny populations, the higher the phytoplasma concentration (88–0% for 1–5 instars nymph, female and male adults), the shorter the development time and the longer the adult lifetime (both male and female). These findings provided research evidence of phytoplasma transmission by insect vectors; however, further investigation of the mechanisms for prevention and management of phytoplasma diseases is needed.

Aiming to identify the complexing mechanisms of heavy metal cations on edge surfaces of 2:1-type clay minerals, systemic first-principles molecular dynamics (FPMD) simulations were conducted and the microscopic structures and complex free energies were obtained. Taking Cd(II) as a model cation, the structures on both (010) and (110) edges of the complexes were derived for the three possible binding sites (≡SiO, ≡Al(OH)2/≡AlOH≡AlSiO, and vacant sites). The stable complexes adsorbed on the three binding sites on both terminations had similar structures. The free energies of the complexes on (010) edges were calculated by using the constrained FPMD method. The free energies of complexes on the ≡SiO and ≡Al(OH)2 sites were similar and they were both significantly lower than the free energy of the complex on the octahedral vacant site. In association with the concept of high energy site (HES) and low energy site (LES) in the 2 Site Protolysis Non Electrostatic Surface Complexation and Cation Exchange (2SPNE SC/CE) sorption model, the vacant site was assigned to HES and the other two sites to LES, respectively.

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.

Linear modal instabilities of flow over untapered wings with aspect ratios $AR=4$ and 8, based on the NACA 0015 profile, have been investigated numerically over a range of angles of attack, $\alpha$, and angles of sweep, $\varLambda$, at chord Reynolds numbers $100\le Re\le 400$. Laminar base flows have been generated using direct numerical simulation and selective frequency damping, as appropriate. Several families of unstable three-dimensional linear global (TriGlobal) eigenmodes have been identified and their dependence on geometric parameters has been examined in detail at $Re=400$. The leading global mode A is associated with the peak recirculation in the three-dimensional laminar separation bubble formed on the wing and becomes unstable when recirculation reaches $\textit {O}(10\,\%)$. On unswept wings, this mode peaks in the midspan region of the wake and moves towards the wing tip with increasing $\varLambda$, following the displacement of peak recirculation; its linear amplification leads to wake unsteadiness. Additional amplified modes exist at nearly the same and higher frequencies compared to mode A. The critical $Re$ has been identified and it is shown that amplification increases with increasing sweep, up to $\varLambda \approx 10^\circ$. At higher $\varLambda$, all global modes become less amplified and are ultimately stable at $\varLambda =30^\circ$. An increase in amplification of the leading mode with sweep was not observed over the $AR=4$ wing, where tip vortex effects were shown to dominate.

Direct numerical simulation is used to investigate effects of turbulent flow in the confined geometry of a face-centred cubic porous unit cell on the transport, clustering and deposition of fine particles at different Stokes numbers ($St = 0.01, 0.1, 0.5, 1, 2$) and at a pore Reynolds number of 500. Particles are advanced using one-way coupling and the collision of particles with pore walls is modelled as perfectly elastic with specular reflection. Tools for studying inertial particle dynamics and clustering developed for homogeneous flows are adapted to take into account the embedded, curved geometry of the pore walls. The pattern and dynamics of clustering are investigated using the volume change of Voronoi tesselation in time to analyse the divergence and convergence of the particles. Similar to the case of homogeneous, isotropic turbulence, the cluster formation is present at large volumes, while cluster destruction is prominent at small volumes and these effects are amplified with the Stokes number. However, unlike homogeneous, isotropic turbulence, the formation of a large number of very small volumes was observed at all Stokes numbers and attributed to the collision of particles with the pore wall. Multiscale wavelet analysis of the particle number density indicates that the peak of the energy density spectrum, representative of enhanced particle clustering, shifts towards larger scales with an increase in the Stokes number. Scale-dependent skewness and flatness quantify the intermittent void and cluster distribution, with cluster formation observed at small scales for all Stokes numbers, and void regions at large scales for large Stokes numbers.

The rise of “the rest,” especially China, has triggered an inevitable transformation of the so-called liberal international order. Rising powers have started to both challenge and push for the reform of existing multilateral institutions, such as the International Monetary Fund (IMF), and to create new ones, such as the Asian Infrastructure Investment Bank (AIIB). The United States under the Trump administration, on the other hand, has retreated from the international institutions that the country once led or helped to create, including the Trans-Pacific Partnership (TPP); the Paris Agreement; the Iran nuclear deal; the Intermediate-Range Nuclear Forces (INF) Treaty; the United Nations Educational, Scientific and Cultural Organization (UNESCO); and the United Nations Human Rights Council (UNHRC). The United States has also paralyzed the ability of the World Trade Organization (WTO) to settle trade disputes by blocking the appointment of judges to its appellate body. Moreover, in May 2020, President Trump announced his decision to quit the Open Skies Treaty, an arms control regime designed to promote transparency among its members regarding military activities. During the past decade or so, both Russia and the United States have been dismantling multilateral arms control treaties one by one while engaging in new nuclear buildups at home.

As part of the roundtable “International Institutions and Peaceful Change,” this essay focuses on the “Kindleberger trap,” a term coined by Joseph Nye Jr. referring to the situation in which no country takes the lead to maintain international institutions in the international system. President Trump's destructive policies toward many international institutions seem to push the current international order to the brink of the Kindleberger trap. Ironically, China has pledged, at least rhetorically, to support and even save these existing international institutions. Based on an institutional-balancing perspective, we suggest that the worry about the Kindleberger trap is unwarranted because the international institutional order will not easily collapse after the decline of U.S. hegemony. Institutional competition among great powers and institutional changes within the institutional order have become two remedies to maintain international institutions and to avoid the Kindleberger trap during the international order transition. What states, including the United States and China, should do is to reembrace and reinvigorate the role of multilateralism in world politics so that the dynamics of institutional balancing and consequential institutional changes in the context of U.S.-China competition do not deprive international society of the public goods and normative values of international institutions. The future international order should not be led by a single country, but by dynamic and balanced international institutions.