Size Dependent Phase Transformation of Liquid Gallium.

As the most popular liquid metal (LM), gallium (Ga) and its alloys are emerging as functional materials due to their unique combination of fluidic and metallic properties near room temperature. As an important branch of utilizing LMs, micro- and submicron-particles of Ga-based LM are widely employed in wearable electronics, catalysis, energy, and biomedicine. Meanwhile, the phase transition is crucial not only for the applications based on this reversible transformation process, but also for the solidification temperature at which fluid properties are lost. While Ga has several solid phases and exhibits unusual size-dependent phase behavior. This complex process makes the phase transition and undercooling of Ga uncontrollable, which considerably affects the application performance. In this work, extensive (nano-)calorimetry experiments are performed to investigate the polymorph selection mechanism during liquid Ga crystallization. It is surprisingly found that the crystallization temperature and crystallization pathway to either α -Ga or ß -Ga can be effectively engineered by thermal treatment and droplet size. The polymorph selection process is suggested to be highly relevant to the capability of forming covalent bonds in the equilibrium supercooled liquid. The observation of two different crystallization pathways depending on the annealing temperature may indicate that there exist two different liquid phases in Ga.

Mitigation Measures Could Aggravate Unbalanced Nitrogen and Phosphorus Emissions from Land-Use Activities.

Socioeconomic factors and mitigation potentials are essential drivers of the dynamics of nutrient emissions, yet these drivers are rarely examined at broad spatiotemporal scales. Here, we combine material flow analysis and geospatial analysis to examine the past and future changes of nitrogen and phosphorus emissions in China. Results show that anthropogenic nitrogen and phosphorus emissions increased by 17% and 32% during 2000-2019, respectively. Meanwhile, many regions witnessed decreasing nitrogen emissions but rising phosphorus discharged to waterbody, leading to a 20% decrease in the nitrogen/phosphorus ratio. In addition to many prominent factors like fertilizer use, the increasing impervious land area around cities is a notable factor driving the emissions, indicating the urgency to limit building expansion, especially in North China Plain and other less-developed regions. Improving land-use efficiency and consuming behaviors could reduce nitrogen and phosphorus emissions by 65-77% in 2030, but the nitrogen/phosphorus ratio will increase unintendedly due to larger reduction potentials for phosphorus, which may deteriorate the aquatic ecosystem. We highlight that nitrogen and phosphorus emissions should be reduced with coordinated but differentiated measures by prioritizing nitrogen reduction through cropland and food-system management.

Association between burnout and post-traumatic stress disorder among frontline nurse during COVID-19 pandemic: A moderated mediation analysis.

AIMS AND OBJECTIVES: The aim of this study was to investigate the relationship between burnout and post-traumatic stress disorder (PTSD) among frontline nurses who went to assist the epidemic situation in Wuhan, China, during the outbreak in 2020. The study also explored the mediating role of depression and the moderating role of age in the main relationship. BACKGROUND: The relationship between burnout and PTSD in nurse has rarely been investigated in the context of the COVID-19 pandemic. Understand the relationship between these variables can provide empirical evidence for developing interventions and protocols that improve the health of nurses in future public health emergencies. DESIGN: An online cross-sectional survey of targeted local 327 nurses who went to assist the COVID-19 epidemic situation in Wuhan during the initial outbreak. METHODS: This study was conducted in August 2020, the burnout scale, the PTSD scale and the depression scale were used to survey participants. The moderated mediation model was used to test research hypotheses. RESULTS: Burnout could affect the PTSD symptoms in nursing staffs and depression could mediate this relationship. Age moderated the relationship between burnout/depression and PTSD, and the effects was strong and significant among younger participants in the relationship between burnout and PTSD. CONCLUSIONS: Burnout was identified as a core risk factor of PTSD in nurses. Depression and age played significant roles in the relationship between burnout and PTSD. RELEVANCE TO CLINICAL PRACTICE: PTSD, as a symptom that manifests after experiencing a stressful event, should be a key concern among frontline healthcare professionals. This study suggests that PTSD in nurses can be further reduced by reducing burnout. Attention should also be paid to the PTSD status of nurses of different age groups. PATIENT OR PUBLIC CONTRIBUTION: Patients and the public were not involved in the design and implementation of this study. Frontline nurses completed an online questionnaire for this study.

Production-Based and Consumption-Based Accounting of Global Cropland Soil Erosion.

The effective control of cropland soil erosion is urgent for all countries because of its threat to global food security. Cropland soil erosion is caused by agricultural production and driven indirectly by consumption. Analyzing the causes and preventive strategies from the consumption side is essential for soil erosion control. However, there is not yet sufficient research or practice. In this study, we estimated global cropland soil erosion with the revised universal soil loss equation, allocated it to specific types of crops, and quantified the cropland soil erosion footprint of the economies with a multiregional input-output analysis model. Our results showed that developed economies, usually importing cropland soil erosion from developing or agriculturally developed economies, are the beneficiaries in the current crop trading system. The European Union is the largest net importer, while Brazil is the largest exporter. The indirect and induced sectors are the main contributors, consuming approximately 70.48% of the total cropland soil erosion. Our results revealed the region- and product-specific contributors that could inform the reduction of global cropland soil erosion for sustainable food production and consumption.

Psychological capital of petrochemical corporate employees during COVID-19 social isolation: a longitudinal analysis.

The COVID-19 pandemic is a major public health emergency and a significant stressor to most people. The objective of this study was to examine the mental health status and social support level of participants from 2019 to 2020. The study aimed to investigate the changes in people's psychological capital state due to the COVID-19 pandemic. A longitudinal study was performed to study the psychosocial predictors of mental health among a sample of 2,999 Chinese employees in 2019, and the follow-up survey was conducted one year later. Regression coefficients were visualized in a heatmap. Path analysis was performed base on the structural equation model (SEM) to measure the associations between study variables. The status of mental health, resilience, and optimism changed significantly during the pandemic (P < 0.05). The level of employee's social support in 2019 could significantly and positively predicted the level of employee's psychological capital in 2020, and the level of employee mental health in 2019 significantly and negatively predicted the level of employee psychological capital in 2020. The mental health of employees played an intermediary role between social support and psychological capital. These results highlight that the COVID-19 pandemic has a strong impact on the psychological capital of company employees. While demanding performance, corporations should ensure timely intervention in the mental health of their employees.

Exploring the environment-nutrition-obesity effects associated with food consumption in different groups in China.

Unsustainable diet is one of the main reasons for the nutrition-health-environment trilemma. However, information on environment-nutrition-obesity effects associated with food consumption is still limited. This study analyzes these diet-related impacts of different groups classified by various socio-economic attributes: location, gender, age, income, education, and occupation. We applied the samples in China Health and Nutrition Survey and divided them into advantaged group and dis-advantaged group according to the probability of access to more nutritious food. Results show that the advantaged groups had higher and more rapidly increasing dietary and nutrition quality than their counterpart during 1997-2011. On the contrary, the non-advantaged group' body mass index increased faster. Meanwhile, the high-income group as well as government and professional & technological workers have passed the criterion for overweight. The environmental footprints, i.e., nitrogen, phosphorus, carbon, and water footprints, of high-income group were higher 89%, 70%, 98%, and 41% than low-income group, respectively. Notably, food consumption sustainability of each group has declined, and the non-advantaged groups' is much more sustainable. We concluded that inequality existed and tends to expand in food consumption and its related impacts of different socio-economic groups. A reformed responsibility allocation system is needed during dietary transition for better environmental management. Strategies to improve dietary quality for advantaged group focus on improving the types of high-quality protein foods, such as milk and seafood, while the non-advantaged group can choose to increase the types of high-quality but relatively cheap foods like vegetables and fruits considering the availability and living cost.

Is the Water System Healthy in Urban Agglomerations? A Perspective from the Water Metabolism Network.

Urban agglomerations are a primary spatial focus of socioeconomic activity and inherently include large volumes of embodied water. We have applied the concept of water metabolism health to comprehensively evaluate the overall operation of water systems in urban agglomerations and propose an innovative assessment framework. In particular, we constructed a water metabolism network (WMN) model to simulate a water system in which different cities and sectors are integrated, combining a newly compiled multiregional input-output (MRIO) table of water flow with ecological network analysis (ENA). A case study considering the Pearl River Delta (PRD) urban agglomeration in 2015 demonstrates that its network is well synergic but highly dependent, with considerable negative effects. Highly developed cities in southeastern of the PRD exhibit higher embodied water productivity and robustness but impose considerable negative effects on the water system. We found the agricultural sector to be a dominant controller of the network; the construction and service sectors represent the primary beneficiaries with strong competition. We suggest measures at various scales to improve water utilization efficiency and promote positive interactions between components, thus improving water metabolism system health for urban agglomerations.

Configuration correlation governs slow dynamics of supercooled metallic liquids.

The origin of dramatic slowing down of dynamics in metallic glass-forming liquids toward their glass transition temperatures is a fundamental but unresolved issue. Through extensive molecular dynamics simulations, here we show that, contrary to the previous beliefs, it is not local geometrical orderings extracted from instantaneous configurations but the intrinsic correlation between configurations that captures the structural origin governing slow dynamics. More significantly, it is demonstrated by scaling analyses that it is the correlation length extracted from configuration correlation rather than dynamic correlation lengths that is the key to determine the drastic slowdown of supercooled metallic liquids. The key role of the configuration correlation established here sheds important light on the structural origin of the mysterious glass transition and provides an essential piece of the puzzle for the development of a universal theoretical understanding of glass transition in glasses.

Transboundary Environmental Footprints of the Urban Food Supply Chain and Mitigation Strategies.

Food supply has been the central issue of human development for millennia and has become increasingly critical in an urbanizing world. However, the environmental footprints and associated mitigation strategies of food consumption have rarely been comprehensively characterized at urban or regional scales. Here, we analyze the water, carbon, reactive nitrogen, and phosphorus footprints of food consumption in Chinese urban regions and demonstrate how such information can help to formulate tailored mitigation strategies. The results show that in three of the largest urban regions of China, 44-93% of the four footprints are embodied in transboundary food supply. The size of the footprints and the effectiveness of mitigation measures in food supply chain vary across the environmental footprints and urban regions. However, targeting agriculture and food processing sectors in Hebei, Shandong, and Henan provinces can reduce these footprints by up to 47%. Our findings show that the analysis of the environmental footprints along the transboundary food supply chains could inform individualized and effective mitigation targets and strategies.

Review on City-Level Carbon Accounting.

Carbon accounting results for the same city can differ due to differences in protocols, methods, and data sources. A critical review of these differences and the connection among them can help to bridge our knowledge between university-based researchers and protocol practitioners in accounting and taking further mitigation actions. The purpose of this study is to provide a review of published research and protocols related to city carbon accounting, paying attention to both their science and practical actions. To begin with, the most cited articles in this field are identified and analyzed by employing a citation network analysis to illustrate the development of city-level carbon accounting from three perspectives. We also reveal the relationship between research methods and accounting protocols. Furthermore, a timeline of relevant organizations, protocols, and projects is provided to demonstrate the applications of city carbon accounting in practice. The citation networks indicate that the field is dominated by pure-geographic production-based and community infrastructure-based accounting; however, emerging models that combine economic system analysis from a consumption-based perspective are leading to new trends in the field. The emissions accounted for by various research methods consist essentially of the scope 1-3, as defined in accounting protocols. The latest accounting protocols include consumption-based accounting, but most cities still limit their accounting and reporting from pure-geographic production-based and community infrastructure-based perspectives. In conclusion, we argue that protocol practitioners require support in conducting carbon accounting, so as to explore the potential in mitigation and adaptation from a number of perspectives. This should also be a priority for future studies.

Pressure effects on structure and dynamics of metallic glass-forming liquid.

Although the structure and dynamics of metallic glass-forming liquids have been extensively investigated, studies of the pressure effects are rare. In the present study, the structural and dynamical properties of a ternary metallic liquid are systematically studied via extensive molecular dynamics simulations. Our results clearly show that, like isobaric cooling, isothermal compression could also slow down the dynamics of metallic liquid, leading to glass formation. However, the temperature- and pressure-induced glass transitions differ in the formation of local coordination structures and the variation of fragility. The increase of the kinetic fragility with increasing pressure is also accompanied by a monotonic structural fragility change. These findings may suggest a link between dynamics and structure. In addition, with increasing pressure, the dynamics becomes more heterogeneous, as revealed by the non-Gaussian parameter and dynamic correlation length. Here the length scales of both slow and fast domains are examined and discussed by analyzing the four-point dynamic structure factor associated with spatial correlations of atomic mobility. These correlation lengths coexist in the metallic liquids and grow comparatively in the considered temperature and pressure ranges. Finally, the scaling relation between the relaxation times and correlation lengths is discussed, which is found to be consistent with the spirit of Adam-Gibbs and random first-order transition theories.

Measuring Urban Carbon Footprint from Carbon Flows in the Global Supply Chain.

A global multiregional input-output (MRIO) model was built for eight Chinese cities to track their carbon flows. For in-depth understanding of urban carbon footprint from the perspectives of production, consumption, and trade balance, four kinds of footprints and four redefined measurement indicators were calculated. From the global supply chain, urban carbon inflows from Mainland China were larger than outflows, while the carbon outflows to European, principal North American countries and East Asia were much larger than inflows. With the rapid urbanization of China, Construction was the largest consumer and Utilities was the largest producer. Cities with higher consumption (such as Dalian, Tianjin, Shanghai, and Beijing) should change their consumption patterns, while cities with lower production efficiency (such as Dalian, Shanghai, Ningbo, and Chongqing) should improve their technology. The cities of net carbon consumption tended to transfer carbon emissions out of them by trading in carbon-intensive products, while the cities of net carbon production tended to produce carbon-intensive products for nonlocal consumers. Our results indicated that urban carbon abatement requires not only rational consumption and industrial symbiosis at the city level, but also tighter collaboration along all stages of the global supply chain.

Thermodynamic scaling of glassy dynamics and dynamic heterogeneities in metallic glass-forming liquid.

A ternary metallic glass-forming liquid is found to be not strongly correlating thermodynamically, but its average dynamics, dynamic heterogeneities including the high order dynamic correlation length, and static structure are still well described by thermodynamic scaling with the same scaling exponent γ. This may indicate that the metallic liquid could be treated as a single-parameter liquid. As an intrinsic material constant stemming from the fundamental interatomic interactions, γ is theoretically predicted from the thermodynamic fluctuations of the potential energy and the virial. Although γ is conventionally understood merely from the repulsive part of the inter-particle potentials, the strong correlation between γ and the Grüneisen parameter up to the accuracy of the Dulong-Petit approximation demonstrates the important roles of anharmonicity and attractive force of the interatomic potential in governing glass transition of metallic glassformers. These findings may shed light on how to understand metallic glass formation from the fundamental interatomic interactions.

Future climate imposes pressure on vulnerable ecological regions in China.

Ecological regions of medium fragility account for 55 % of China's land. Large-scale afforestation and land reclamation have been carried out in these areas over the past few decades. However, how future climate change poses risks and challenges to them remains unclear. By establishing a multi-algorithm framework combining machine learning algorithms with multi-source dataset, our work predicts Normalized Difference Vegetation Index (NDVI, a proxy for vegetation greenness) and its variations in the 21st century under different climate scenarios. We find that vegetation greening (i.e., NDVI increase) in northern and southwestern China is unstable over four 20-year periods from 2020 to 2100. However, a strikingly prominent greening is expected to occur on the Qinghai-Tibet Plateau until the end of this century. Future warming can not only exacerbate the difficulties of vegetation conservation and restoration in vulnerable ecological regions, also threaten these new croplands, stymieing ambitions to increase crop production in China. Our results underscore the crucible that a warming climate presents to current restoration projects. We highlight the urgency of adapting to climate change to achieve ambitious goals of carbon sequestration and food security in China.

Revealing the role of liquid preordering in crystallisation of supercooled liquids.

The recent discovery of non-classical crystal nucleation pathways has revealed the role of fluctuations in the liquid structural order, not considered in classical nucleation theory. On the other hand, classical crystal growth theory states that crystal growth is independent of interfacial energy, but this is questionable. Here we elucidate the role of liquid structural ordering in crystal nucleation and growth using computer simulations of supercooled liquids. We find that suppressing the crystal-like structural order in the supercooled liquid through a new order-killing strategy can reduce the crystallisation rate by several orders of magnitude. This indicates that crystal-like liquid preordering and the associated interfacial energy reduction play an essential role in nucleation and growth processes, forcing critical modifications of the classical crystal growth theory. Furthermore, we evaluate the importance of this additional factor for different types of liquids. These findings shed new light on the fundamental understanding of crystal growth kinetics.

The Russia-Ukraine war disproportionately threatens the nutrition security of developing countries.

While the ongoing Russia-Ukraine war threatens global nutrition security, the magnitude and extent of its impact remain underexamined. Here we show that, with the lowest level of war duration, severity, sanction, and countries involved, the direct and indirect impacts of the war and sanctions could newly place 67.3 million people (roughly equals the total population of France) in undernourishment and 316.7 million people (roughly equals the total population of Bangladesh and Russia) suffering from extreme national food insecurity. Approximately 95% of the affected population are from developing countries, highlighting the vulnerability of food supply in these countries. Both the undernourished population and its inequality across countries will substantially grow, if war duration and severity increase. If the war is prolonged to early 2024, future agricultural growth cannot fully offset the negative impacts, and global hunger will still very likely exacerbate. We conclude that targeted measures should be placed in developing countries and their vulnerable populations to reconstruct a just, healthy, and environmentally sustainable food system. Supplementary Information: The online version contains supplementary material available at 10.1007/s43621-022-00112-8.

Study on the enhancement method of online monitoring image of dense fog environment with power lines in smart city.

In this research, an image defogging algorithm is proposed for the electricity transmission line monitoring system in the smart city. The electricity transmission line image is typically situated in the top part of the image which is rather thin in size. Because the electricity transmission line is situated outside, there is frequently a sizable amount of sky in the backdrop. Firstly, an optimized quadtree segmentation method for calculating global atmospheric light is proposed, which gives higher weight to the upper part of the image with the sky region. This prevents interference from bright objects on the ground and guarantees that the global atmospheric light is computed in the top section of the image with the sky region. Secondly, a method of transmission calculation based on dark pixels is introduced. Finally, a detail sharpening post-processing based on visibility level and air light level is introduced to enhance the detail level of electricity transmission lines in the defogging image. Experimental results indicate that the algorithm performs well in enhancing the image details, preventing image distortion and avoiding image oversaturation.

Relationships Between Depressive Symptoms, Interpersonal Sensitivity and Social Support of Employees Before and During the COVID-19 Epidemic: A Cross-lag Study.

This study examined the correlation between depressive symptoms, interpersonal sensitivity, and social support before and during the COVID-19 pandemic and verified causal relationships among them. The study used Social Support Scale and Symptom Self-Rating Scale to investigate relevant variables. A total of 1,414 employees from company were recruited for this longitudinal study, which a follow up study was conducted on the same group of participants 1 year later. Paired sample t-test results showed that significant differences were only found in social support, not in depressive symptoms or interpersonal sensitivity. The results of correlation analysis showed that social support, depressive symptoms, and interpersonal sensitivity were significantly correlated between wave 1 and wave 2. The cross-lag autoregressive pathway showed that employees' social support level, depressive symptoms, and interpersonal sensitivity all showed moderate stability. Crossing paths showed that wave 1 social support could significantly predict wave 2 depressive symptoms (ß = -0.21, p < 0.001) and wave 2 interpersonal sensitivity (ß = -0.21, p < 0.001). Wave 1 depressive symptoms (ß = -0.10, p < 0.01) could significantly predict wave 2 social support, while wave 1 interpersonal sensitivity (ß = 0.07, p = 0.10) could not predict wave 2 social support. Social support can be considered as a protective factor against mental health problems.

Effect of family stress on life satisfaction among female workers during the COVID-19 epidemic in China: Exploring the roles of anxiety symptoms and age.

The study aimed to investigate the level of life satisfaction (LS) among Chinese female workers after resuming work during the COVID-19 epidemic, and to further explore the potential mediating and moderating roles in the association between family stress and LS. Self-reported questionnaires were completed by 10,175 participants. Results showed that the level of LS decreased. The family stress had a negative effect on LS, and the effect was mediated by anxiety symptoms. Additionally, age moderated the direct and indirect effects within this relationship. Interventions aiming to improve LS should consider these aspects and younger workers should be given special attention.

Recovery of structure and activity of disintegrated aerobic granular sludge after long-term storage: Effect of exogenous N-acyl-homoserine lactones.

Long-term storage of aerobic granular sludge (AGS) may lead to granule inactivation and disintegration. Granule recovery in both structure and activity is important for scale-up and stability of AGS, but information about the structure recovery of stored AGS is limited. In addition, whether short-term exogenous N-acyl-homoserine lactones (AHLs) regulations could accelerate the granule recovery and sustain positive effects on AGS is unknown. Herein, the recovery of 33-month stored AGS was performed in three reactors for 38 days (phase I) at different exogenous AHLs concentrations (0, 50 and 500 nM of AHL-mixtures in R0, R1 and R2, respectively) and for an extended 45 days without exogenous AHLs (phase II). Results demonstrated successful recovery of disintegrated AGS in all reactors, although it was relatively time-consuming in R0. The treatment performance was similar among the reactors and steady-state removal of COD (90%) and NH4+-N (94%) could be recovered within 7 and 21 days, respectively. However, exogenous AHLs regulation (especially in R1) obviously accelerated bioactivity recovery of heterotrophs and nitrifiers and improved granule characteristics, including biomass, density, hydrophobicity and extracellular polymeric substance (EPS). During phase II, sustainable positive effects remained in R1, but granule characteristics deteriorated in R2. The abundance of functional genera Thauera, Nitrosomonas and Candidatus_Nitrotoga, contributed to the rapid recovery and helped maintain the structure and activity of AGS. The predictive functional profiling of bacterial communities also demonstrated sustainably higher activities of metabolism, growth and signal sensing under exogenous AHLs regulation at an appropriate content.