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The groundwater resource is crucial to the urbanization and industrialization in the Guangdong coastal area; the rapid development of Daya Bay has presented a challenge for the management of the groundwater quantity and quality. Therefore, a novel approach to hydrochemical analysis, which, combined with the health risk model and the water quality index (WQI), was used to explain the hydrochemistry characteristics and risks to human health of groundwater in the Guangdong coastal areas in addition to investigating the factors controlling groundwater quality. The results showed that the average concentration of total dissolved solids (TDS) in groundwater was 1935.26 mg/L and the quality of water was weakly alkaline. The dominant hydrochemical types of groundwater were identified to be Mg-HCO3 and Na-Cl·HCO3. The main factor influencing the hydrochemical composition was rock weathering, while the result of principal component analysis (PCA) shows seawater intrusion and anthropogenic inputs also have an effect on the water quality. The conclusions of the water quality assessment indicated that most of the groundwater samples were acceptable for drinking. However, both WQI and the non-carcinogenic hazard quotient (HQ) values indicated unacceptable risks in any area of Maoming, Zhanjiang and Shantou, and, according to the hazard index (HI) value, children in the study area are at more danger to health risks than adults. It is suggested that both groundwater salinization and nitrate pollution should be paid attention to when improving groundwater quality and exploring the sustainable utilization of groundwater resources. [ABSTRACT FROM AUTHOR]

The classification of urban functional areas plays an important role in urban planning and resource management. Although previous studies have confirmed that different urban functional areas have different morphological structures and Land Surface Temperature (LST) characteristics, these two types of characteristics have rarely been fully integrated and used for functional area classification. In this paper, a new framework for classifying urban functional areas is proposed by combining urban morphological features and LST features. First, metrics are constructed from three levels, namely, building, road and region, which are used to portray urban morphology; LST is retrieved using thermal infrared remote sensing to reflect LST features with four metrics: the average temperature, maximum temperature, temperature difference and standard deviation of temperature. Then, the functional areas are classified into four categories: service/public land, commercial land, residential land and industrial land. A random forest algorithm is used to effectively fuse the features of these two categories and classify the functional areas. The effectiveness of the proposed framework is tested in the study area of Shenzhen City, Guangdong Province. The results show that the combined classification accuracy of the proposed classification method is 0.85, which is 0.26 higher than that of the classification model based on urban morphology and 0.1 higher than that of the classification model based on LST features. The proposed framework verifies that the integration of LST features into urban functional area classification is reliable and effectively combines urban morphology and LST features for functional area classification. [ABSTRACT FROM AUTHOR]

The current-limiting performance of the dc resistive-type superconducting fault current limiter (dc R-SFCL) is vital to the reliability in the high voltage dc current (HVDC) transmission system. It is expensive and difficult to utilize the discharging process of the precharged dc capacitor to evaluate the current-limiting performance. In this paper, a R-Q curve based evaluation method for current-limiting performance of dc R-SFCLs in dc system is proposed, which replaces the dc impulse experiment with ac impulse experiment. A ± 160kV dc SFCL prototype is designed by Guangdong Power Grid Co., Ltd., and tested to acquire the experimental heat accumulation Q and the experimental R-Q curve. Accordingly, the mathematical model consistent with the prototype is built in PSCAD. Finally, a fault condition is simulated in dc system to verify the feasibility of the R-Q curve based evaluation method. It is shown that the proposed method has superior properties in simplifying the testing platform, reducing the test requirements and costs, and providing reference for precise modeling of SFCLs. [ABSTRACT FROM AUTHOR]

While urban redevelopment has been a global phenomenon for many decades, the redevelopment of urban villages (villages-in-the-city or c hengzhongcun) in China has attracted increasing scholarly attention in recent years. However, few studies focus on urban planning forces and their impacts on the redevelopment of urban villages, especially the transformation of open spaces. This paper therefore examines how urban planning transforms the space of urban villages through a case study of Yangji Village in Guangzhou City, Guangdong Province. The large increase in public spaces related to the transformation of Yangji results from collaborative governance driven by trends in urbanization and the work of urban planners. The latter are empowered by their strategic use of state support, professional knowledge and public interest incentives. However, in the Yangji redevelopment, as a state-hegemonic project, such planner-led collaborative governance remains limited in scope amid the exclusion of migrant tenants from decision-making. Although rarely regarded in the literature as playing a key role in redeveloping urban villages, this paper highlights urban planners as a salient force in the morphology of urban villages. Without challenging the hegemonic substance of urban village redevelopment, planners can coordinate with and occasionally manipulate other stakeholders to legitimate and facilitate negotiation during physical planning. Hence, redeveloped urban forms, rather than stakeholders' economic profits in short-term redevelopment, may influence urban lives in the long term due to planners' efforts. • Multiple stakeholders form collaborative governance in the physical planning of Yangji Village redevelopment to increase much open space. • The collaborative dynamics in the physical planning are built upon stakeholders' trust, fostered through informal meetings, led by planners, and fundamentally driven by urbanization. • Such collaborative governance is limited, largely due to the exclusion of migrant tenants. • Planners define the field of urban form beyond economic profit to improve redevelopment without challenging neoliberal and authoritarian hegemony. • State support, professional knowledge, and public interest ensure planners' leading role in collaboration. [ABSTRACT FROM AUTHOR]

• An incentive mechanism is introduced to improve the responsive load model. • A real-time price mechanism is proposed based on the balance of supply and demand in flexible islanded microgrid (FIMG). • The definitions of FIMG flexibility and flexibility insufficiency rate (FIR) are given, and the importance of FIR in the hybrid energy storage system (HESS) capacity optimization is verified by a case study. • The NSGA-II and the improved TOPSIS are used to obtain the optimal solution. The islanded microgrid (IMG) is universally accepted as an important method to solve the island power supply problem. The optimal capacity of the hybrid energy storage system (HESS) is necessary to improve safety, reliability, and economic efficiency in an IMG. To improve the IMG ability to deal with uncertainty, this paper proposed a flexible islanded microgrid (FIMG) model with real-time price (RTP)-based demand response (DR). Through RTP to guide users' electricity consumption behaviors more in line with renewable energy sources (RES) output law, the capacity allocation of the HESS was optimized and the system had sufficient flexibility in each scheduling period. In this paper, two decision variables of the HESS, the number of lead-acid batteries and supercapacitors, were determined based on the objective of comprehensive operating cost (COC) and flexibility insufficiency rate (FIR) minimization. Firstly, the non-dominated sorting genetic algorithm II (NSGA-II) was devoted to obtaining the Pareto set that satisfies the FIMG day-ahead scheduling. Then, both the loss of produced power probability (LPPP) and the loss of power supply probability (LPSP) corresponding to each Pareto solution were gotten based on the real-time dispatch strategy. Finally, taking COC, FIR, LPPP, and LPSP as evaluation indicators, the improved Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) was applied to select the optimal solution from the Pareto set. In the case study, a FIMG on an island in Guangdong province was analyzed and discussed. By studying typical days in winter and summer of the FIMG, the superiority of the proposed model and methods was verified. [ABSTRACT FROM AUTHOR]

Objective: The present study aimed to evaluate the long-term outcomes and prognostic factors of elderly patients with hepatocellular carcinoma (HCC) undergoing hepatectomy.Material and Methods: From January 1983 to December 2006, 2,283 patients with HCC received hepatectomy in Sun Yat-sen University Cancer Center. The clinicopathological data and treatment outcomes of 67 elderly HCC patients (elderly group, > or =70 years of age) and 268 patients (control group, <70 years of age) who were selected randomly from the 2216 younger patients were compared retrospectively.Results: The elderly HCC patients had lower hepatitis B surface antigen-positive rate (P < 0.001), lower rate of marked alpha-fetoprotein elevation (P = 0.004), higher infection rate of hepatitis C virus (P = 0.010), more preoperative comorbidities (P < 0.001), higher rate of tumor encapsulation (P = 0.040), and better overall survival rate (P = 0.017); whereas there were no significant differences between these two groups in other factors, including gender ratio, liver function, accompanying cirrhosis, pathological tumor-node-metastasis (pTNM) staging, satellite nodules, vascular invasion, tumor rupture, resection margin, intraoperative blood loss, incidence of postoperative complications, hospital mortality, and disease-free survival rate. Multivariate analysis showed that pTNM staging was an independent prognostic factor of long-term survival in elderly patients with HCC.Conclusion: HCC in the elderly was less HBV-associated, less advanced, and less aggressive. Hepatectomy for selected elderly patients with HCC possibly have a better curative effect compared with younger patients. For the elderly patients without preoperative comorbidities or with controlled comorbidities, hepatectomy is a safe and effective treatment. pTNM staging is the only independent predictor of postoperative overall survival in elderly HCC patients. [ABSTRACT FROM AUTHOR]

Background: COVID-19 has spread all around the world. Italy is one of the worst affected countries in Europe. Although there is a trend of relief, the epidemic situation hasn't stabilized yet. This study aims to investigate the dynamics of the disease spread in Italy and provide some suggestions on containing the epidemic. Methods: We compared Italy's status at the outbreak stage and control measures with Guangdong Province in China by data observation and analysis. A modified autonomous SEIR model was used to study the COVID-19 epidemic and transmission potential during the early stage of the outbreak in Italy. We also utilized a time-dependent dynamic model to study the future disease dynamics in Italy. The impact of various non-pharmaceutical control measures on epidemic was investigated through uncertainty and sensitivity analyses. Results: The comparison of specific measures implemented in the two places and the time when the measures were initiated shows that the initial prevention and control actions in Italy were not sufficiently timely and effective. We estimated parameter values based on available cumulative data and calculated the basic reproduction number to be 4.32 before the national lockdown in Italy. Based on the estimated parameter values, we performed numerical simulations to predict the epidemic trend and evaluate the impact of contact limitation, detection and diagnosis, and individual behavior change due to media coverage on the epidemic. Conclusions: Italy was in a severe epidemic status and the control measures were not sufficiently timely and effective in the beginning. Non-pharmaceutical interventions, including contact restrictions and improvement of case recognition, play an important role in containing the COVID-19 epidemic. The effect of individual behavior changes due to media update of the outbreak cannot be ignored. For policy-makers, early and strict blockade measures, fast detection and improving media publicity are key to containing the epidemic. [ABSTRACT FROM AUTHOR]

The lift-off operation of the offshore wind turbine jacket foundation from a barge is investigated in this study. Firstly, the hydrodynamic analysis of the two ships is carried out via AQWA, considering the series configuration and L-shaped configuration. The damping lid method is introduced to address viscous correction and validated by a frequency-time-domain validation. The damping lid factor for the two configurations are set to be 0.02 and 0.04. The time-domain simulation of multi-body lifting system, including lifting wires, slings, and deck fenders, are then carried out. In the nonstationary time-domain simulation, the sensitivity of wave direction, vessel configuration and deck fender stiffness are investigated, indicating that the most critical stage during the lift-off operation corresponds to when about 70% weight of the jacket is lifted by the heavy-lift vessel. The series configuration under head sea in 70% load transfer stage is chosen for subsequent steady-state simulations. Extreme value analysis is carried out based on the Gumbel distribution. The allowable sea states are then evaluated. The operability is obtained by using the 20-year hindcast wave data of three certain sites off Guangdong, Fujian and Zhejiang coast, which are 60%, 55% and 65%, respectively. • Hydrodynamics of different configurations of two-ship for the lift-off operation of OWT jacket foundation are compared. • The damping lid method embedded in AQWA is applied to effectively reduce the errors induced by hydrodynamic interactions. • Nonstationary dynamic analysis is performed to identify the critical stage during the lift-off operation. • The influence of two-ship configuration, incident wave angle and deck fenders are investigated. • Extreme response and operability analysis are evaluated to provide operational probabilities for specific sites. [ABSTRACT FROM AUTHOR]

Background: Upper gastrointestinal cancers (including oesophageal cancer and gastric cancer) are the most common cancers worldwide. Artificial intelligence platforms using deep learning algorithms have made remarkable progress in medical imaging but their application in upper gastrointestinal cancers has been limited. We aimed to develop and validate the Gastrointestinal Artificial Intelligence Diagnostic System (GRAIDS) for the diagnosis of upper gastrointestinal cancers through analysis of imaging data from clinical endoscopies.Methods: This multicentre, case-control, diagnostic study was done in six hospitals of different tiers (ie, municipal, provincial, and national) in China. The images of consecutive participants, aged 18 years or older, who had not had a previous endoscopy were retrieved from all participating hospitals. All patients with upper gastrointestinal cancer lesions (including oesophageal cancer and gastric cancer) that were histologically proven malignancies were eligible for this study. Only images with standard white light were deemed eligible. The images from Sun Yat-sen University Cancer Center were randomly assigned (8:1:1) to the training and intrinsic verification datasets for developing GRAIDS, and the internal validation dataset for evaluating the performance of GRAIDS. Its diagnostic performance was evaluated using an internal and prospective validation set from Sun Yat-sen University Cancer Center (a national hospital) and additional external validation sets from five primary care hospitals. The performance of GRAIDS was also compared with endoscopists with three degrees of expertise: expert, competent, and trainee. The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of GRAIDS and endoscopists for the identification of cancerous lesions were evaluated by calculating the 95% CIs using the Clopper-Pearson method.Findings: 1 036 496 endoscopy images from 84 424 individuals were used to develop and test GRAIDS. The diagnostic accuracy in identifying upper gastrointestinal cancers was 0·955 (95% CI 0·952-0·957) in the internal validation set, 0·927 (0·925-0·929) in the prospective set, and ranged from 0·915 (0·913-0·917) to 0·977 (0·977-0·978) in the five external validation sets. GRAIDS achieved diagnostic sensitivity similar to that of the expert endoscopist (0·942 [95% CI 0·924-0·957] vs 0·945 [0·927-0·959]; p=0·692) and superior sensitivity compared with competent (0·858 [0·832-0·880], p<0·0001) and trainee (0·722 [0·691-0·752], p<0·0001) endoscopists. The positive predictive value was 0·814 (95% CI 0·788-0·838) for GRAIDS, 0·932 (0·913-0·948) for the expert endoscopist, 0·974 (0·960-0·984) for the competent endoscopist, and 0·824 (0·795-0·850) for the trainee endoscopist. The negative predictive value was 0·978 (95% CI 0·971-0·984) for GRAIDS, 0·980 (0·974-0·985) for the expert endoscopist, 0·951 (0·942-0·959) for the competent endoscopist, and 0·904 (0·893-0·916) for the trainee endoscopist.Interpretation: GRAIDS achieved high diagnostic accuracy in detecting upper gastrointestinal cancers, with sensitivity similar to that of expert endoscopists and was superior to that of non-expert endoscopists. This system could assist community-based hospitals in improving their effectiveness in upper gastrointestinal cancer diagnoses.Funding: The National Key R&D Program of China, the Natural Science Foundation of Guangdong Province, the Science and Technology Program of Guangdong, the Science and Technology Program of Guangzhou, and the Fundamental Research Funds for the Central Universities. [ABSTRACT FROM AUTHOR]