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Marine science and technology talents are important resources and core elements for promoting the high-quality development of marine economy. This paper constructs a theoretical mechanism of marine science and technology talent agglomeration affecting the green total factor productivity of the marine economy, selects the data of 11 coastal provinces and cities in China from 2006 to 2019 for empirical testing, and further analyzes the mediating role of marine industrial structure upgrading and the moderating role of environmental regulation. The study finds that: there is a significant inverted U-shaped relationship between marine scientific and technological talent agglomeration and the green total factor productivity of the marine economy; there is regional heterogeneity in the impact of marine scientific and technological talent agglomeration on the green total factor productivity of the marine economy, with coastal areas south of the Yangtze River Basin showing a significant inverted U-shaped relationship, while the relationship is insignificant in coastal areas north of the Yangtze River Basin; the upgrading of marine industry structure plays a mediating role in the influence of marine scientific and technological talent agglomeration on the green total factor productivity of the marine economy, and the upgrading of marine industry structure can significantly promote the green total factor productivity of the marine economy; environmental regulation reinforces the inverted U-shaped impact of marine science and technology talent agglomeration on green total factor productivity in the marine economy. Based on this, policy recommendations are put forward to rationally guide the concentration of talents, focus on the matching of talents and industries, and optimize the environment for the development of talents.

In order to evaluate the autonomous combat effectiveness of ground-attack UAV efficiently, quickly and objectively, weighted mean of vectors algorithm (INFO) and K-fold cross-validation method are introduced to optimize the random forest algorithm (RF) to find the optimal parameter combination, and an autonomous combat effectiveness evaluation method based on optimized random forest is proposed. Firstly, based on the theory of weighted mean of vectors algorithm, the number and maximum depth of the random forest decision tree model are optimized. Secondly, combined with the ground-attack UAV combat tasks, the main operational factors of autonomous combat effectiveness evalua-tion are analyzed, the evaluation index system of autonomous combat effectiveness of ground-attack UAV is summarized, and the evaluation model of autonomous combat effectiveness of UAV based on INFO-RF is established. Finally, the evaluation model is verified by an example and compared with the traditional RF model, GA-RF model and SVM model. The results show that the output results of INFO-RF model have higher fitting degree and more accurate evaluation value. The results of the example effectively verify the rationality of the proposed method and the reliability of the optimization model.

Taking the application of artificial intelligence technology in the field of low altitude flight as an breakthrough point, this paper analyzes the challenges of unmanned platform, intelligent control and multi-task of low-altitude aircraft driven by artificial intelligence (AI) technology, which bring about multi-complex control objects, increasing control difficulty and expanding space-time depth. It puts forward the main decision-making methods and development approaches of improving the efficiency of flight examination and approval by pre-practice decision-making, real-time monitoring of flight status by autonomous decision-making, and accurate handling of violations by data-driven decision-making. This paper analyzes the main points, advantages and disadvantages of the application of artificial intelligence technology, soft killing technology and hard damage technology in the construction of management control and emergency treatment.

Green development and carbon neutrality in 2060 have become China's national development strategy. Land reclamation and ecological restoration in mining areas are the only way to green development of coal industry. It is found that in addition to restoring green and ecological functions, it also has a dual role in increasing carbon sinks, which not only prevents and suppresses carbon emissions due to land damage, but also increases carbon sinks due to vegetation and ecological restoration by analyzing the properties of land reclamation and ecological restoration in mining areas. Therefore, mining area ecological restoration is a green technology for increasing carbon sinks, which is in line with the national development strategy and will usher in new development opportunities. The incentive of the carbon neutral policy to the ecological restoration of the mining area is mainly embodied in seven aspects: guiding the scientific restoration, setting the leading standards, carrying out scientific and technological research, implementing the main responsibilities of enterprises, setting the project demonstration, strengthening financial support and establishing the market mechanism. Five major technical challenges will be faced by the ecological restoration of mining areas under the guidance of carbon neutrality: ① Carry out the research on the effect of reducing carbon and increasing sink of ecological restoration in mining areas from the four aspects of monitoring objectives, measurement parameters, parameter acquisition and calculation methods, and simultaneously carry out the assessment of reducing carbon and increasing sink of ecological restoration in mining areas; ② Leading role of the ecological restoration planning in the mining area in the increase of carbon sinks is played through the planning incorporating the concept of carbon neutrality, the planning measures and schemes for the increase of carbon sinks, and the optimization of restoration schemes based on carbon sink; ③ In addition to considering the function of water and soil conservation traditionally, increases the design and comparative analysis of increasing the carbon sink function in landform remodeling design; ④ Scientifically analyze and evaluate the sink increasing effect of different soil reconstructions, popularize sink increasing soil reconstruction technology, and simultaneously research the sink increasing reconstruction materials and soil profile; ⑤ Research and develop plant community selection and vegetation restoration technologies considering both ecological benefits and sink enhancement effects.

Objective To evaluate the clinical manifestations, pathological features, treatment methods and prognosis of aggressive fibromatosis of the head and neck. Methods One patient with aggressive fibromatosis of the neck was analyzed, and the relevant literature was reviewed. Results Head and neck lesions account for approximately 12 to 15% of aggressive fibromatosis, which is a rare type of borderline tumor that is commonly characterized by a hard texture, painlessness (but occasionally with pain), hidden growth and poor mobility. Such tumors can result in facial deformity and invasion of the skull base or main nerves, and blood vessels and can compress the airway. MRI is the preferred method for preoperatively determining the size and location of the lesion. The characteristic low T1 and T2 signals of collagen fiber are helpful for the diagnosis of the tumor. The disease has clear pathological features, with tumors consisting of long spindle fibroblasts and myofibroblasts arranged in parallel fascicles with various levels of collagen formation. The tumor cells exhibit the characteristics of infiltrative growth, ill ⁃ defined cell membranes and variable amounts of cytoplasm. Pathologic mitosis and atypia are not seen. Characteristic immunohistochemical features include expression of Vim(+), HHF⁃35(+), CD34(⁃), S⁃100(⁃) and Ki⁃67(+). The disease is locally invasive, and patients may relapse easily, but distant metastases are not observed. The primary treatment is surgical resection. Chemotherapy, hormone therapy and biological treatments have auxiliary functions in the treatment of these tumors. Conclusion Aggressive fibromatosis of the head and neck has no specific clinical features; the diagnosis depends primarily on pathological examination. The main treatment is radical surgical resection. Radiotherapy, chemotherapy and biological treatment can be used in combination with surgery in cases of incomplete resection or recurrence.

Although plenty of studies have been carried out, waterlogging in urban areas is common. The frequent happening of flood inundation in urban underground spaces has great threat to the sustainable development of city and the life and property security of citizens. Firstly, according to the flooding events in urban underground spaces around the world, the basic information and characteristics of flood disasters in urban underground spaces were introduced in this study. The characteristics of flood disasters in underground spaces were analyzed from four aspects, including inundation development, rescue condition, invasion pattern, and damage feature. Then, the major scientific problems of flood control in urban underground spaces were raised from three aspects, i. e. factors, carriers, and defenders, based on which the difficulties, vulnerabilities, and poor executions were summarized and discussed. The influences on flood preventing of designed rainfalls, physical property and non-structural measures were concluded. Next, with an overview of related studies, studies on flood control in urban underground spaces were divided into two types, one based on flood control in urban areas and the other focused on features of under-ground spaces, both of which were analyzed in detail. Finally, an outlook of academic study and technical improvement on prospective flood control in urban underground spaces was conducted, as a scientific perspective to the development of sustainable societies and resilient cities. [ABSTRACT FROM AUTHOR]

Ice wear is one of important factors affecting the damage of hydraulic concrete. In order to investigate the wear law of natural pumice concrete under ice friction, natural pumice in Inner Mongolia was used as coarse aggregate, and the effects of volume fraction of pumice aggregate, water-binder ratio and cementitious material hardness on the wear of natural pumice concrete were studied. The significance of different influencing factors on the wear amount of natural pumice concrete was analyzed. The apparent morphology of natural pumice concrete under ice wear was observed by super depth of field microscope. The results show that the wear amount of natural pumice concrete increases with the increase of pumice aggregate volume fraction and water-binder ratio, and decreases with the increase of cementitious material hardness. The volume fraction of pumice aggregate and water-binder ratio have significant effects on the wear amount of natural pumice concrete. The surface material of natural pumice concrete falls off under the action of cutting and fatigue wear mechanisms. The hole wall of the worn surface is damaged and the holes are enlarged. [ABSTRACT FROM AUTHOR]

As the only inland sea of China, Bohai Sea has been regarded as the integrated part of the national territorial space toward green and high-quality development in the new era. The comprehensive environmental treatment in Bohai Sea has achieved noticeable progress, but the problems remain. The trend of biological and ecological degradation of Bohai Sea has not been fundamentally curbed. Guided by President Xi Jinping thought on ecological civilization and on building a maritime community with a shared future, China should join into the Implementation Plan for the United Nations Decade of Marine Science for Sustainable Development (2021-2030), and manage to formulate Bohai Sea Decade Action Plan for Green and High-quality Development. The proposed action plan should aim at establishing "Clean Bohai Sea", "Ecological Bohai Sea", "Low-carbon Bohai Sea", and "High-quality Bohai Sea", and enhancing special projects in terms of science and technology, ecology, industry, and management. China would set up a typical module of regional sea sustainable development worldwide. [ABSTRACT FROM AUTHOR]

Sagittal split ramus osteotomy (SSRO) is a versatile orthognathic procedure for correcting mandibular deformities. Various complications can possibly occur when performing SSRO, and it can even cause serious adverse consequences because of the complexity of anatomy and operative procedures. The types of complications and their accompanying clinical manifestations are closely related to the choice of diagnosis and treatment strategies and clinical outcomes. To discuss the causes, prevention, and treatment measures of various common complications of SSRO, domestic orthog-nathic surgery experts prepared this consensus to increase the awareness of SSRO complications, thereby ensuring safe surgical procedure and good results. [ABSTRACT FROM AUTHOR]

Sagittal split ramus osteotomy (SSRO) is a versatile orthognathic procedure for correcting mandibular deformities. Various complications can possibly occur when performing SSRO, and it can even cause serious adverse consequences because of the complexity of anatomy and operative procedures. The types of complications and their accompanying clinical manifestations are closely related to the choice of diagnosis and treatment strategies and clinical outcomes. To discuss the causes, prevention, and treatment measures of various common complications of SSRO, domestic orthognathic surgery experts prepared this consensus to increase the awareness of SSRO complications, thereby ensuring safe surgical procedure and good results.

Objective: To explore the application of digital positioning guide plate in extraction of impacted supernumerary teeth and evaluate its clinical efficacy., Methods: From March to August, 2019, 30 patients with labial impacted supernumerary teeth treated in the Department of Oral and Maxillofacial Surgery, Stomatological Hospital, Southern Medical University were enrolled in this study. Fifteen of the patients were treated with digital positioning guide plate to remove the impacted supernumerary teeth (test group). According to the CBCT data and the dentition model of the patients, the positioning guide plate was positioned by avoiding the important anatomical structure with the tooth-bone surface as the support to design the soft tissue incision line and bone tissue exposure range. The other 15 patients who were treated without the use of the guide plate for operation served as the control group. The design time, tooth searching time, operation time and complications were compared between the two groups., Results: The positioning guide plate was well attached during the operation and allowed quick location of the supernumerary teeth while helping to expose the supernumerary teeth and avoid the damage of the adjacent important anatomical structures. The pre-operative design time was 50 ± 5 min in the test group and 0 min in the control group. The average time of tooth finding in the test group was 5±2 min, as compared with 10±3 min in the control group ( t =15.40, P < 0.01); the average time of operation was significantly shorter in the test group than in the control group (25±4 min vs 45±6 min; t =35.50, P < 0.01). No intraoperative complications occurred in the test group, and slight deviation occurred in one case in the control group., Conclusions: The application of digital positioning guide plate in extraction of embedded supernumerary teeth can significantly shorten the time of tooth finding, reduce the difficulty of operation, and improve the quality of operation.

Objective: To study and evaluate the clinical effects of combined preoperative chemotherapy and their relations with multi drug resistance (MDR)., Methods: 102 cases with oral squamous cell carcinoma(OSCC) were included in the study (63 males and 39 females, aged 22 to 67 years). Among the subjects there were 57 cases with cancer of tongue and 45 cases with cancer of buccal mucosa. 27 cases in the group were classified as stage II, 55 as stage III and 20 cases as stage IV according to TNM standard. All cases accepted PYM + 5-Fu + DDP combined chemotherapy pre-operatively. The total given dose was PYM 48 mg, 5-Fu 7.5 g and DDP 300 mg. After the chemotherapy, radical surgery were performed within 2 weeks. The diagnosis of all cases were proved as OSCC by biopsy., Results: Total effective rate of the combined chemotherapy was 82.4%. All of the cases were followed up and their 3 years' survival rate was 67.6%., Conclusion: The combined chemotherapy of PYM + 5-Fu + DDP is effective in using as one of comprehensive treatment for OSCC.

Objective: The aim of this study was to analyze the clinical characters, diagnosis and treatment of primary neoplasms in the parapharyngeal regions., Methods: A total of 115 cases of primary neoplasms in the parapharyngeal regions were included in this study., Results: Disorders of swallowing, breath or speaking were the common symptoms of neoplasms in parapharyngeal regions. The majority of neoplasms parapharyngeal regions were benign. 46 cases were from the deep lobe of the parotid, and 42 cases were neurogenic. CT or MRI provides useful information such as their sizes, shapes and extents. The relationship between the tumor and vessel was shown using super-selective angiography. All the tumors were resected completely by extra-oral approach through the posteroinferior incision of the mandible. The follow-up was carried out from 1 to 10 years, and the data indicated that 2 patients died, 18 cases were lost, and others had no recurrence., Conclusion: CT and/or MRI are essentially useful for diagnosis and presurgical planning. Super-selective angiography can be used if the lesions involved carotid artery. Posteroinferior incision of the mandible is a simple, effective and safe approach for excision of neoplasms parapharyngeal regions.