Coupling of Oxygen Vacancies and Heterostructure on Fe3 O4 via an Anion Doping Strategy to Boost Catalytic Activity for Lithium-Sulfur Batteries.

The sluggish reaction kinetics and severe shutting behaviors of sulfur cathodes are the major roadblocks to realizing the practical application of lithium-sulfur (Li-S) batteries and need to be solved through designing/constructing rational sulfur hosts. Herein, an effective alternative material of Fe3 O4- x /FeP in-situ embedded in N-doped carbon-tube (Fe3 O4- x /FeP/NCT) is proposed. In this fabricated heterostructure, NCT skeleton works as a sulfur host provides physical barrier for lithium polysulfides (LiPSs), while Fe3 O4- x /FeP heterostructure with abundant oxygen vacancies provides double active centers to simultaneously accelerate e- /Li+ diffusion/transport kinetics and catalysis for LiPSs. Through the respective advantages, Fe3 O4- x /FeP/NCT exhibits synergy enhancement effect for restraining sulfur dissolution and enhancing its conversion kinetics. Furthermore, the promoted ion diffusion kinetics, enhanced electrical conductivity, and increased active sites of Fe3 O4- x /FeP/NCT are enabled by oxygen vacancies as well as the heterogeneous interfacial contact, which is clearly confirmed by experimental and first-principles calculations. By virtue of these superiorities, the constructed cathode shows excellent long-term cycling stability and a high-rate capability up to 10 C. Specially, a high areal capacity of 7.2 mAh cm-2 is also achieved, holding great promise for utilization in advanced Li-S batteries in the future.

Does Nepal Have the Agriculture to Feed Its Population with a Sustainable Diet? Evidence from the Perspective of Human-Land Relationship.

Nepal is one of the least developed countries in the world, with more than 80% of the population engaged in agricultural production and more than two-fifths of the population still living below the poverty line. Ensuring food security has always been a key national policy in Nepal. Using a nutrient conversion model and an improved resource carrying capacity model as well as statistical data and household questionnaires, an analysis framework for food supply balance is developed in this study, which quantitatively analyzes the balance of food supply and demand in Nepal from the perspectives of food and calories during the period 2000-2020. Nepal's agricultural production and consumption have increased significantly, and the diet has been relatively stable over the past two decades. The diet structure is stable and homogeneous, with plant products occupying the absolute position in overall dietary consumption. The supply of food and calories varies widely from region to region. Although the increasing supply level at the national scale can meet the needs of the current population, the food self-sufficiency level cannot meet the needs of the local population development at the county level due to the influence of population, geographical location, and land resources. We found that the agricultural environment in Nepal is fragile. The government can improve agricultural production capacity by adjusting the agricultural structure, improving the efficiency of agricultural resources, improving the cross-regional flow of agricultural products, and improving international food trade channels. The food supply and demand balance framework provided a reference for achieving balance between the supply and demand of food and calories in a resource-carrying land and provides a scientific basis for Nepal to achieve zero hunger under the framework of the Sustainable Development Goals. Furthermore, development of policies in order to increase agricultural productivity will be critical for improving food security in agricultural countries such as Nepal.

Diagnostic performance of deep learning-based vessel extraction and stenosis detection on coronary computed tomography angiography for coronary artery disease: a multi-reader multi-case study.

BACKGROUND: Post-processing and interpretation of coronary CT angiography (CCTA) imaging are time-consuming and dependent on the reader's experience. An automated deep learning (DL)-based imaging reconstruction and diagnosis system was developed to improve diagnostic accuracy and efficiency. METHODS: Our study including 374 cases from five sites, inviting 12 radiologists, assessed the DL-based system in diagnosing obstructive coronary disease with regard to diagnostic performance, imaging post-processing and reporting time of radiologists, with invasive coronary angiography as a standard reference. The diagnostic performance of DL system and DL-assisted human readers was compared with the traditional method of human readers without DL system. RESULTS: Comparing the diagnostic performance of human readers without DL system versus with DL system, the AUC was improved from 0.81 to 0.82 (p < 0.05) at patient level and from 0.79 to 0.81 (p < 0.05) at vessel level. An increase in AUC was observed in inexperienced radiologists (p < 0.05), but was absent in experienced radiologists. Regarding diagnostic efficiency, comparing the DL system versus human reader, the average post-processing and reporting time was decreased from 798.60 s to 189.12 s (p < 0.05). The sensitivity and specificity of using DL system alone were 93.55% and 59.57% at patient level and 83.23% and 79.97% at vessel level, respectively. CONCLUSIONS: With the DL system serving as a concurrent reader, the overall post-processing and reading time was substantially reduced. The diagnostic accuracy of human readers, especially for inexperienced readers, was improved. DL-assisted human reader had the potential of being the reading mode of choice in clinical routine.

Pattern changes of ecological product trade in countries along the Belt and Road.

The Belt and Road Initiative (BRI) was designed to promote economic and trade cooperation between countries along the Belt and Road (B&R), specifically by building an international trade network. Ecological resources are the basis for human survival. Countries along the B&R transform ecological resources into ecological products by production activities. These products can then be used for trade, thereby driving the countries' economic development. This study uses net primary productivity (NPP) as a unified measure of ecological products, and explores the pattern changes of ecological product trade in countries along the B&R, from 2013 to 2019 (from the BRI proposal to the outbreak of COVID-19). The purpose of the study is to reveal the impact of the BRI on the trade of ecological products. The results show that (1) the trade scale of ecological products in the B&R region has changed significantly. The total volume of traded ecological products increased from 2071.74 to 2631.00 TgC. This represented an increase of about 26.99%, or 7.41% higher than the global average. (2) The spatial distribution pattern of ecological product trade did not change significantly in countries along the B&R. However, the gravity centers of the total and net trade volume of ecological products moved 120.74 km to the northeast and 392.98 km to the southeast, respectively. (3) The trade structure of ecological products in the B&R region, six sub-regions, and most countries remained relatively stable. Only the proportion of the livestock products trade in Mongolia and the proportion of the forest products trade in Bhutan have increased significantly. This finding suggests that the strength and breadth of the construction of unimpeded trade in countries along the B&R still need to further strengthened, in order to accelerate the realization of the vision of the Green Silk Road.

Three-Dimensional Electrochromic Soft Photonic Crystals Based on MXene-Integrated Blue Phase Liquid Crystals for Bioinspired Visible and Infrared Camouflage.

Developing bioinspired camouflage materials that can adaptively change color in the visible and infrared (IR) regions is an intriguing but challenging task. Herein, we report an emerging strategy for fabricating dynamic visible and IR camouflage materials by the controlled in situ growth of novel photopolymerizable blue phase liquid crystals with cubic nanoarchitectures onto highly aligned MXene nanostructured thin films. The resulting MXene-integrated 3D soft photonic crystals exhibit vivid structural colors and reversible switching between a bright colored state and a dark black state under a low DC electric field. As an illustration, proof-of-concept pixelated devices that allow for pixel-controllable electrochromism are demonstrated. Furthermore, a free-standing electrochromic flexible film of such 3D soft photonic crystals is fabricated, where visible electrochromism and thermal camouflage are enabled by leveraging the superior electrothermal conversion and low mid-IR emissivity of MXene nanomaterials.

The U-box ubiquitin ligase TUD1 promotes brassinosteroid-induced GSK2 degradation in rice.

Brassinosteroids (BRs) are a class of steroid hormones with great potential for use in crop improvement. De-repression is usually one of the key events in hormone signaling. However, how the stability of GSK2, the central negative regulator of BR signaling in rice (Oryza sativa), is regulated by BRs remains elusive. Here, we identify the U-box ubiquitin ligase TUD1 as a GSK2-interacting protein by yeast two-hybrid screening. We show that TUD1 is able to directly interact with GSK2 and ubiquitinate the protein. Phenotypes of the tud1 mutant are highly similar to those of plants with constitutively activated GSK2. Consistent with this finding, GSK2 protein accumulates in the tud1 mutant compared with the wild type. In addition, inhibition of BR synthesis promotes GSK2 accumulation and suppresses TUD1 stability. By contrast, BRs can induce GSK2 degradation but promote TUD1 accumulation. Furthermore, the GSK2 degradation process is largely impaired in tud1 in response to BR. In conclusion, our study demonstrates the role of TUD1 in BR-induced GSK2 degradation, thereby advancing our understanding of a critical step in the BR signaling pathway of rice.

Rice DWARF AND LOW-TILLERING and the homeodomain protein OSH15 interact to regulate internode elongation via orchestrating brassinosteroid signaling and metabolism.

Brassinosteroid (BR) phytohormones play crucial roles in regulating internode elongation in rice (Oryza sativa). However, the underlying mechanism remains largely unclear. The dwarf and low-tillering (dlt) mutant is a mild BR-signaling-defective mutant. Here, we identify two dlt enhancers that show more severe shortening of the lower internodes compared to the uppermost internode (IN1). Both mutants carry alleles of ORYZA SATIVA HOMEOBOX 15 (OSH15), the founding gene for dwarf6-type mutants, which have shortened lower internodes but not IN1. Consistent with the mutant phenotype, OSH15 expression is much stronger in lower internodes, particularly in IN2, than IN1. The osh15 single mutants have impaired BR sensitivity accompanied by enhanced BR synthesis in seedlings. DLT physically interacts with OSH15 to co-regulate many genes in seedlings and internodes. OSH15 targets and promotes the expression of the BR receptor gene BR INSENSITIVE1 (OsBRI1), and DLT facilitates this regulation in a dosage-dependent manner. In osh15, dlt, and osh15 dlt, BR levels are higher in seedlings and panicles, but unexpectedly lower in internodes compared with the wild-type. Taken together, our results suggest that DLT interacts with OSH15, which functions in the lower internodes, to modulate rice internode elongation via orchestrating BR signaling and metabolism.

The divergence of brassinosteroid sensitivity between rice subspecies involves natural variation conferring altered internal auto-binding of OsBSK2.

Japonica/geng and indica/xian are two major rice (Oryza sativa) subspecies with multiple divergent traits, but how these traits are related and interact within each subspecies remains elusive. Brassinosteroids (BRs) are a class of steroid phytohormones that modulate many important agronomic traits in rice. Here, using different physiological assays, we revealed that japonica rice exhibits an overall lower BR sensitivity than indica. Extensive screening of BR signaling genes led to the identification of a set of genes distributed throughout the primary BR signaling pathway with divergent polymorphisms. Among these, we demonstrate that the C38/T variant in BR Signaling Kinase2 (OsBSK2), causing the amino acid change P13L, plays a central role in mediating differential BR signaling in japonica and indica rice. OsBSK2L13 in indica plays a greater role in BR signaling than OsBSK2P13 in japonica by affecting the auto-binding and protein accumulation of OsBSK2. Finally, we determined that OsBSK2 is involved in a number of divergent traits in japonica relative to indica rice, including grain shape, tiller number, cold adaptation, and nitrogen-use efficiency. Our study suggests that the natural variation in OsBSK2 plays a key role in the divergence of BR signaling, which underlies multiple divergent traits between japonica and indica.

Cold Chain Food and COVID-19 Transmission Risk: From the Perspective of Consumption and Trade.

Since the outbreak of the coronavirus disease 2019 (COVID-19), political and academic circles have focused significant attention on stopping the chain of COVID-19 transmission. In particular outbreaks related to cold chain food (CCF) have been reported, and there remains a possibility that CCF can be a carrier. Based on CCF consumption and trade matrix data, here, the "source" of COVID-19 transmission through CCF was analyzed using a complex network analysis method, informing the construction of a risk assessment model reflecting internal and external transmission dynamics. The model included the COVID-19 risk index, CCF consumption level, urbanization level, CCF trade quantity, and others. The risk level of COVID-19 transmission by CCF and the dominant risk types were analyzed at national and global scales as well as at the community level. The results were as follows. (1) The global CCF trade network is typically dominated by six core countries in six main communities, such as Indonesia, Argentina, Ukraine, Netherlands, and the USA. These locations are one of the highest sources of risk for COVID-19 transmission. (2) The risk of COVID-19 transmission by CCF in specific trade communities is higher than the global average, with the Netherlands-Germany community being at the highest level. There are eight European countries (i.e., Netherlands, Germany, Belgium, France, Spain, Britain, Italy, and Poland) and three American countries (namely the USA, Mexico, and Brazil) facing a very high level of COVID-19 transmission risk by CCF. (3) Of the countries, 62% are dominated by internal diffusion and 23% by external input risk. The countries with high comprehensive transmission risk mainly experience risks from external inputs. This study provides methods for tracing the source of virus transmission and provides a policy reference for preventing the chain of COVID-19 transmission by CCF and maintaining the security of the global food supply chain.

Exploring adaptive approaches for social-ecological sustainability in the Belt and Road countries: From the perspective of ecological resource flow.

The countries along the Belt and Road (B&R) are characterized by fragile ecosystems and underdevelopment economy. International trade usually transferred the eco-environmental negative impacts to developing countries. How to avoid the conflict between economic development and eco-environmental protection is the primary concern of building the Green Silk Road. To discover the adaptive strategies for ensuring the sustainability of the social-ecosystem in countries along the B&R, this study analyzes the supply-consumption relationship of ecological resources by simulating the flow of net primary productivity between the ecosystem and the social system. The results show that: (1) The flow of ecological resources between agricultural and husbandry systems have effectively alleviated the local ecological pressure caused by animal husbandry in countries along the B&R. Animal husbandry in developed countries economize the local ecological resources by importing feed, while mitigating the grazing pressure by utilizing the local crop residues in underdeveloped agricultural countries. (2) International trade not only enables countries with insufficient ecological resources to meet their demands by importing ecological products and thus alleviate ecosystem pressure, but also promotes countries with sufficient ecological resources to transform their resource advantages into economic advantages by exporting without at the expense of ecological sustainability. (3) For underdeveloped countries, the dependence of economic development on ecological resources is at the expense of the living demands of residents, only if the economy could have leap-forward improvement the allocation of ecological resources within the social system would be inclined to living demands. These adaptive approaches not only provide the evidences of ecological-social sustainable development by promoting the reasonable flow and allocation of ecological resources, but also imply the necessary assistance for the underdeveloped countries to guarantee the basic human well-being in economic development.

Superamphiphilic Chitosan Cryogels for Continuous Flow Separation of Oil-In-Water Emulsions.

Chitosan is a typical hydrophilic biomass building block widely used in material science and engineering. However, its intrinsic amphiphilicity has been seldom noted so far. Herein, a series of glutaraldehyde-crosslinked chitosan cryogels with superamphiphilicity are fabricated at moderately frozen conditions through a freezing-thawing process. The micron-sized porous cryogel samples display a 0° contact angle toward both water and oil, 0° water contact angle under oil, and over 120° oil contact angle underwater. By comparing the wetting behavior of the tablet compressed by pure chitosan powders, the superamphiphilicity of the chitosan sample is proven to be independent on crosslinkers. This special wettability endows the chitosan cryogels with high separation efficiency for various surfactant-stabilized oil-in-water emulsions under continuous flow mode driven by gravity as well as a peristaltic pump.

Mechanochromic, Shape-Programmable and Self-Healable Cholesteric Liquid Crystal Elastomers Enabled by Dynamic Covalent Boronic Ester Bonds.

Endowing a cholesteric liquid crystal elastomer (CLCE) exhibiting a helicoidal nanostructure with dynamically tailorable functionalities is of paramount significance for its emerging applications in diverse fields such as adaptive optics and soft robotics. Here, a mechanochromic, shape-programmable and self-healable CLCE is judiciously designed and synthesized through integrating dynamic covalent boronic ester bonds into the main-chain CLCE polymer network. The circularly polarized reflection of CLCEs can be reversibly and dynamically tuned across the entire visible spectrum by mechanical stretching. Thanks to the introduction of dynamic boronic ester bonds, the CLCEs were found to show robust reprogrammable and self-healing capabilities. The research disclosed herein can provide new insights into the development of 4D (color and 3D shape) programmable photonic actuators towards bioinspired camouflage, adaptive optical systems, and next-generation intelligent machines.

The external dependence of ecological products: Spatial-temporal features and future predictions.

The instability of international trade can threaten the resource security of resource-importing countries, while international trade helps address spatial mismatches between regional populations, economies, and resources. Ecological products are the basis for human survival and development, in which agri-livestock products are especially sensitive to trade fluctuation and closely related to human well-being. The external dependence is an important indicator to reveal the external supply risk of regional resources. Scientific understanding the external dependence of ecological products can reveal the potential risks of trade fluctuations to human well-being and ecological sustainability. In this study, the global status and trend of countries' external dependence of agri-livestock ecological products are investigated. The results showed that nearly 80% (141) of countries relied on imports to meet ecological product demands in 2018, in which Asian-African-Latin countries accounted for about 78%, which indicated that the instability of international trade would threaten the ecological resource security in 80% of the world's countries, especially for underdeveloped countries. Even worse, 68% of countries are increasing their external dependence of ecological products. Even if the intensity of ecological resource exploitation reaches the maximum sustainable utilization level, 60% (113) of countries are expected to need imports for meeting their ecological product demands in 2050. Moreover, even considering the agricultural technological upgrade and the consumption transformation, more than 50% (94) of countries are still net importers of ecological products. Therefore, trade liberalization is still one of the important means to reduce resource security risks caused by trade instability. More notably, half of the countries in the world may sacrifice ecological sustainability to meet basic human well-being in the future under deglobalization.

Sub-national climate change risk assessment: A case analysis for Tibet and its prefecture-level cities.

Avoiding climate change from exceeding its critical threshold is a serious challenge facing humanity at present and in the future. As the mode of global cooperative action is stranded, multi-center and multi-level efforts are needed to deal with global warming in the future. In order to provide information for the formulation of low-carbon development policies, it is essential to assess the maintain or cross of climate change threshold on different scales. In this study, the carbon footprint calculated based on the process coefficient approach is systematically integrated with the climate change indicator of the planetary boundaries framework improved with the goals of the Paris Agreement to identify the climate change risks of Tibet and its prefecture-level cities from 2000 to 2017. Moreover, the main driving factors behind carbon footprint were analyzed. The findings showed that: (1) Since 2000, Tibet's CO2 emissions have demonstrated steady and rapid increase. The sector composition is dominated by cement production-related and transportation sector-related emissions. The type composition is dominated by diesel-related, process-related, and coal-related emissions. There are significant differences in CO2 emissions among all prefecture-level cities, with Lhasa having the largest contribution. (2) Except for Lhasa and Shannan's CO2 emissions that have crossed their critical threshold of climate change and are in an unsafe state, Tibet and other prefecture-level cities have not yet crossed their critical threshold. (3) Except for Ngari, per capita GDP, energy intensity, population size, and carbon intensity positively affect the increase of CO2 emissions in Tibet and its prefecture-level cities. Our study helps actors at less aggregated scales to determine appropriate policy strengths based on globally agreed goals and ambitions in the process of responding to global warming in a bottom-up manner.

Bioinspired Color-Changing Photonic Polymer Coatings Based on Three-Dimensional Blue Phase Liquid Crystal Networks.

Photonic polymer coatings that can adaptively respond to the constant changes of surrounding environments are of profound significance for diverse applications such as optical sensors, information encryption, and adaptive camouflage. Here, we report the fabrication of humidity-driven color-changing photonic polymer coatings on the basis of judiciously designed hydrogen-bonded three-dimensional (3D) blue phase liquid crystal networks. Thanks to the inherent self-assembled 3D photonic nanostructures and tough covalent bonding between the polymers and substrate surfaces, the resulting polymer coatings are found to exhibit vivid structural colors, and humidity-driven reversible color changes across the visible spectrum of light can be achieved upon breaking the hydrogen bonds and subsequent conversion into a hygroscopic polymer coating. As the proof-of-concept applications, we demonstrate the information encryption, inkjet-printable photonic patterns, bioinspired adaptive camouflage, and colorimetric humidity sensor with such promising humidity-driven color-changing photonic polymer coatings. The results disclosed herein are expected to provide new insights into the development of stimuli-responsive advanced functional materials with tailorable 3D photonic nanostructures toward technological applications ranging from sensing, display, anticounterfeiting, and biomimetic camouflage.

Risk of Global External Cereals Supply under the Background of the COVID-19 Pandemic: Based on the Perspective of Trade Network.

International food trade is an integral part of the food system, and the COVID-19 pandemic has exposed the fragility of external food supplies. Based on the perspective of cereals trade networks (CTN), the pandemic risk is combined with the trade intensity between countries, and an assessment model of cereals external supply risk is constructed that includes external dependence index (EDI), import concentration, and risk of COVID-19 from import countries index (RICI). The results show that: (1) the global main CTN have typical scale-free characteristics, and seven communities are detected under the influence of the core countries; (2) about 60%, 50%, and 70% of countries face risks of medium and above (high and very high) external dependence, concentration of imports, and COVID-19 in the country of origin, respectively. Under the influence of the pandemic, the risk of global external cereal supply index (RECSI) has increased by 65%, and the USA-CAN communities show the highest risk index; (3) the countries with a very high risk are mainly the Pacific island countries and the Latin American and African countries. In addition, Japan, Mexico, South Korea, and 80% of the net food-importing developing countries are at high or very high RECSI levels. Approximately 50% of countries belong to the compound risk type, and many export countries belong to the RICI risk type; (4) global external food supply is subjected to multiple potential threats such as trade interruption, "price crisis", and "payment dilemma". The geographical proximity of community members and the geographical proximity of the pandemic risk is superimposed, increasing the regional risk of external food supply; and (5) this study confirms that the food-exporting countries should avoid the adoption of food export restriction measures and can prevent potential external supply risks from the dimensions of maintaining global food liquidity and promoting diversification of import sources. We believe that our assessment model of cereals external supply risk comprises a useful method for investigations regarding the international CTN or global food crisis under the background of the pandemic.

Diversification of plant agronomic traits by genome editing of brassinosteroid signaling family genes in rice.

Brassinosteroids (BRs) regulate various agronomic traits such as plant height, leaf angle, and grain size in rice (Oryza sativa L.); thus, BR signaling components are promising targets for molecular rational design. However, genetic materials for BR-signaling genes or family members remain limited in rice. Here, by genome editing using clustered regularly interspaced short palindromic repeats (CRSPR)/Cas9 tools, we generated a panel of single, double, triple, or quadruple mutants within three BR signaling gene families, including GSK3/SHAGGY-LIKE KINASE1 (GSK1)-GSK4, BRASSINAZOLE-RESISTANT1 (OsBZR1)-OsBZR4, and protein phosphatases with kelch-like (PPKL)1-PPKL3, under the same background (Zhonghua11, japonica). The high-order mutants were produced by either simultaneously targeting multiple sites on different genes of one family (GSKs and PPKLs) or targeting the overlapping sequences of family members (OsBZRs). The mutants exhibited a diversity of plant height, leaf angle, and grain morphology. Comparison analysis of the phenotypes together with BR sensitivity tests suggested the existence of functional redundancy, differentiation, or dominancy among the members within each family. In addition, we generated a set of transgenic plants overexpressing GSK2, OsBZR1/2, and PPKL2, respectively, in wild-type or activated forms with fusion of different tags, and also verified the protein response to BR application. Collectively, these plants greatly enriched the diversity of important agronomic traits in rice. We propose that editing of BR-related family genes could be a feasible approach for screening of desired plants to meet different requirements. Release of these materials as well as the related information also provides valuable resources for further BR research and utilization.

Dynamic emulsion droplets enabled by interfacial assembly of azobenzene-functionalized nanoparticles under light and magnetic field.

HYPOTHESIS: The ability to control the assembly of micro/nanosized particles at liquid-liquid interface with external inputs promises new opportunities in nanofabrication and biomedicines. This work aims to demonstrate a way to control of dynamic assembly of nanoparticles at liquid-liquid interface by light and magnetic field, which consequently enables the formation of dynamic emulsion droplets. EXPERIMENTS: Magnetic Fe3O4 nanoparticles functionalized with azobenzene moieties (Fe3O4@AZO) were synthesized and were dispersed in toluene/(N,N-dimethylformamide, DMF) binary solvent. After irradiation with UV or visible light, the assembly behavior of these Fe3O4 nanoparticles were evaluated by electron microscopy and fluorescent microscopy. FINDINGS: Under UV light, Fe3O4@AZO nanoparticles were self-assembled due to the increase of dipolar interaction from the photoisomerization of azobenzene and polar molecules, DMF, were harvested from a binary solvent of DMF/toluene. While under visible light, a relief of dipolar interactions between Fe3O4@AZO nanoparticles can induce the secondary assembly of these Fe3O4@AZO nanoparticles at DMF-toluene interface, resulting in DMF droplets covered by a layer of nanoparticle superlattices. More importantly, coupled with a magnetic field, these emulsion droplets can be shaped into one dimensional ones during the interfacial assembly process, thereby giving rise to dynamic emulsions controlled by light and magnetic field.

Dynamic assessment of ecological sustainability and the associated driving factors in Tibet and its cities.

With the general decline of the life support system on earth, it is of great value to carry out ecological sustainability research. This study used the improved ecological footprint (EF) model to calculate the EF of Tibet and its cities (prefecture-level administrative regions) from 2005 to 2017, quantified its ecological sustainability, and analyzed its driving factors using the logarithmic mean divisia index method. The study found that: (1) The EF of Tibet is steadily increasing, yet its distribution among cities is extremely uneven. The size of the internal sub-footprints is different and the distribution is extremely uneven in each city; (2) The ecology of Tibet and other cities is in a safe state, except for Lhasa that is in a completely unsafe state. The ecological footprint diversity index of Tibet, Lhasa, Qamdo, and Shannan showed a downward trend, while the other cities are the opposite. The coordination is deteriorating between the ecological and economic systems of Lhasa and Ngari, while the opposite is for Tibet and other cities; (3) The EF growth of Tibet and its cities is mainly driven by per unit of GDP, population size and footprint structure. The footprint intensity is a decisive factor in slowing down the growth of EF. This research is helpful for actors at all levels to identify the appropriate strength and type of policies to achieve ecologically sustainable development.

Regulation of Brassinosteroid Signaling and Salt Resistance by SERK2 and Potential Utilization for Crop Improvement in Rice.

The complex roles of the steroid hormone brassinosteroids (BRs) in many different yield- and stress-related traits make it difficult to utilize the hormones for crop improvement. Here, we show that SERK2 as a BR signaling component is a potentially useful candidate for BR manipulation in rice. We generated multiple mutant alleles of SERK2 by CRISPR/Cas9 editing and show that knockout of SERK2 results in a compact structure accompanied with increased grain size. SERK2 is localized on plasma membrane and can interact with OsBRI1, the BR receptor, suggesting its conserved role as co-receptor in BR signaling. Consistently, the mutant has impaired BR sensitivity compared to wild type. Notably, the mutant is highly sensitive to salt stress as evaluated by plant survival rate as well as transcriptome analysis, whereas has slightly increased sensitivity to ABA, the stress hormone. By contrast, overexpression of SERK2 significantly enhances grain size and salt stress resistance, importantly, without affecting plant architecture. Furthermore, while salt suppresses SERK2 transcription, the protein is greatly induced by salt stress. Taken together, we propose that the adverse condition induces SERK2 accumulation to enhance early BR signaling on plasma membrane in favor of the anti-stress response. Our results illustrate the great potentials of specific BR components such as SERK2 for crop improvement by utilizing flexible strategies.