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Background: Giant cell tumor of bone (GCTB) is a locally aggressive bone tumour aggravated by stromal cell proliferation and metastasis. Objective: We investigated the mechanism of action of human chorionic gonadotropin (HCG) in mediating GCTB proliferation and invasion. Methods: The expression of HCG was quantified using quantitative real-time PCR. After the primary stromal cells were isolated and identified, the function of HCG in GCTB was estimated using the cell counting kit-8, flow cytometry, scratch experiment, transwell assay, Western blot, and immunofluorescence. Moreover, the mechanism of HCG was assessed through western blotting. Results: HCG expression was decreased in clinical tissue samples from patients with GCTB. We validated that HCG repressed stromal cell proliferation, migration, invasion, autophagy, and epithelial-mesenchymal transition (EMT) and promoted cell apoptosis in GCTB. We also verified that HCG repressed the autophagy and EMT of stromal cells through the Smad signaling axis in GCTB. HCG inhibited the transduction of the Smad signaling pathway by restraining the binding of the TGF-β II receptor to ligand Activin A. Conclusion: HCG restrained the Smad signaling pathway by antagonizing TGF-β signaling in GCTB. HCG may serve as a useful patent to treat GCTB.

Day-ahead prediction of electricity market price is a key for market participants to make a bidding strategy. While numerous methods for day-ahead market price (DMP) forecasting have been developed and applied, those lack interpretable models for DMP forecasting. This study provides a new hybrid model for DMP forecasting, centered on eXtreme Gradient Boosting (XGBoost). The suggested proposal uses neural networks (NNs) with entity embedding (EE) to preprocess categorical feature data and applying Shapley Additive exPlanations (SHAP) to select optimal features. In addition, the weights of NNs and SHAP are interpretability methods. The embedding weights from NNs can reveal the distribution of categorical features in the multi-dimensional space by t-distributed Stochastic Neighbor Embedding (t-SNE). SHAP can explain the impact of input features on the forecast result by assessing the importance of global and local features. The proposed model has been proven to be high accuracy, interpretability and outperforms other models on the test set accuracy, including support vector machine, artificial neural works, classification and regression trees, and random forest). Furthermore, the study found that those load/capacity ratios, the historical clearing prices, penetration of renewable energy, month, hour, weekdays, and weekends have a substantial impact on the prediction of the DMP.

Daily inflow forecasts provide important decision support for the operations and management of reservoirs. Accurate and reliable forecasting plays an important role in the optimal management of water resources. Numerous studies have shown that decomposition integration models have good prediction capacity. Considering the nonlinearity and unsteady state of daily incoming flow data, a hybrid model of adaptive variational mode decomposition (VMD) and bidirectional long- and short-term memory (Bi-LSTM) based on energy entropy was developed for daily inflow forecast. The model was analyzed using the mean absolute error (MAE), the root means square error (RMSE), Nash–Sutcliffe efficiency coefficient (NSE), and correlation coefficient (r). A historical daily inflow series of the Baozhusi Hydropower Station, China, is investigated by the proposed VMD-BiLSTM with hybrid models. For comparison, BP, GRNN, ELMAN, SVR, LSTM, Bi-LSTM, EMD-LSTM, and VMD-LSTM, were adopted and analyzed for evaluation and analyzed. We found that the proposed model, with MAE = 38.965, RMSE = 64.783, and NSE = 95.7%, was superior to the other models. Therefore, the hybrid model is robust and efficient for forecasting highly nonstationary and nonlinear streamflow. It can be used as the preferred data-driven tool to predict the daily inflow flow, which can ensure the safe operation of hydropower stations in reservoirs. As an interdisciplinary field spanning both machine learning and hydrology, daily inflow forecasting can become an important breakthrough in the application of deep learning to hydrology.

Compared with a run-of-river power station, a reservoir power station (RPS), with the capacity of a seasonal regulation function and more, has the unique and irreplaceable attributes of its role in the power grid and society at large. However, under the current power system and market environment in China, these attributes cannot be effectively utilised, resulting in heavy losses to enterprises. It is inevitable for RPSs to participate in the market; therefore, how to improve the profitability of RPS enterprises has become an urgent problem requiring a solution. Based on the control effect on run-off of RPS in a river basin, a new cascade hydropower bidding method and the associated bidding process are proposed. The market entities of the new bidding method are composed of cascade hydropower joints with the RPS as the boundary. The bidding unit benefit-sharing mechanism is constructed, and the accounting method for the benefit-sharing price of the RPS is established, which finally achieves the goal of improving the profitability of the RPS enterprise. Highlights The concept of a virtual reservoir is proposed for the first time, and the bidding process is designed.; Combined with the benefit of the storage capacity of the RPS, a reservoir capacity method that takes into account the actual reservoir water level and the grid absorption rate is established to verify the contribution of the RPS to the bidding benefit.

Complementation with hydropower is an important solution to solve the problems of grid connection and consumption of photovoltaic generation. Considering the randomicity of photovoltaic output and runoff, hydropower station with good regulation capability is often used as a complementary power source of photovoltaic generation. However, there are only a small number of regulatory hydropower stations, which is difficult to meet complementary requirements of widely distributed photovoltaic power stations. The present study aimed to explore the feasibility of using a small cascade hydropower station group as the only complementary power source for photovoltaic generation. Based on electric energy production and output fluctuation, this study constructed a hydro-photovoltaic complementary operation model with dual-objectives of maximization of average capacity factor of the system and load rate of power generation. An algorithm coupling flower pollination algorithm with progressive optimality algorithm (coupling algorithm) was put forward to obtain solutions. The simulation results of the model showed that the fluctuation in joint operation mode is significantly lower than that in single operation mode, and the comprehensive target value on sunny day calculated by the coupling algorithm is 2.53% and 2.16% higher than the results of flower pollination algorithm and progressive optimality algorithm, respectively, verifying the reliability and rationality of the model and the algorithm.

Background The transforming growth factor β regulator 4 (TBRG4) has been proved to be involved in various types of tumor. However, its contribution in human osteosarcoma (OS) is still unclear. Patients and methods In the present study, immunohistochemistry and quantitative real-time PCR were performed to investigate the expression of TBRG4 in OS tissues obtained from patients and three types of cell lines. The effect of TBRG4 knockdown using lentivirus on tumorigenesis was detected by CCK8, high-content screening analysis, colony formation assay and flow cytometric analysis. Bioinformatics analysis was operated to investigate related signaling pathways following TBRG4 knockdown. Results The results showed that the expression of TBRG4 increased significantly in OS tissues and MG63 cell line. TBRG4 knockdown inhibited cell proliferation, colony and tumor formation, while activating cell apoptosis. Ingenuity Pathway Analysis and Western blot assay further indicated that TBRG4 knockdown may regulate the proliferation of human MG63 cells through PI3K/Akt signaling pathway. Conclusion Our results suggest that TBRG4 may become a promising therapeutic target for the treatment of human OS.

Hydropower is a clean, low-carbon renewable energy source with the merits of mature technology and flexible operation. Moreover, hydropower plants provide comprehensive utilization functions in many areas, including flood control, shipping, and emission reduction. In the current contradictive situation between power supply and demand, China's hydropower grid pricing mechanism does not reflect the positive externality of hydropower, which is not conducive to fair competition between hydropower and other power sources. This study proposed the concept of the positive external electricity price (PEEP) and a pricing mechanism that considered, for the first time, the values of hydropower positive externality factors by using the positive externality theory. A representative quasi-public welfare power plant of the Sichuan power grid was used to empirically evaluate the model. The pricing mechanism of reservoir power plants proposed in this paper considered the power grid benefits, flood control benefits, shipping benefits, and emission reduction benefits of hydropower, and allowed for the internalization of the positive externality. The hydropower grid prices based on our recommendations did not cause a dramatic impact on the local power grid; furthermore, the model helped promote the social responsibility of power companies through the pricing guidance for improving economic benefits by increasing positive externalities.

A new round of reform of China's electricity market was launched in 2015 to encourage competition among power generation companies. For cascade hydropower stations under multi-partite ownership, an alliance has become a way to improve competitiveness, but the stability of such alliances is affected by multiple factors. Because of the fierce competition caused by incomplete marketisation and oversupply, some hydropower stations show bounded rationality. In this work, the replicator dynamic mechanism was used to analyse the alliance stability of cascade hydropower stations: this provided a two-dimensional (2D) continuous dynamic system and the specific steps for its solution. After detailed analysis of the existence and stability of the equilibrium solution in the 2D continuous dynamic system and the Jacobian matrix, the parameters for convergence process analysis were assessed. The numerical simulation showed that the alliance is positively related to the common additional income and the penalty factor, and has a negative correlation with a single party's initial investment. It was also found that there is an optimal proportion of common additional income distribution, which makes the alliance most likely to succeed.

How cascade hydropower stations (CHSs) play the electricity market game is regarded as an important issue. The majority of the work to date has focused on short-term horizons and several simplifications in the hydropower system. If future prices are expected to be higher than the current price, CHSs with large reservoirs allow the bidder to postpone energy production for a longer time scale, such as several months or more, which generally matches with the regulation period of the reservoir. Rejecting the assumption of simplifying the hydropower system (ASHS), the long-term bidding strategy of CHSs is discussed for a price-maker based on the supply function equilibrium (SFE). This study considers multiple price-makers, time-coupling, and the characteristics of the hydropower system, with significant challenges. The difference from the conventional model is that the long-term optimal scheduling model of CHSs is added. Moreover, a new methodology is proposed, the equilibrium curve of the uniform clearing price (UCP) is introduced, and the Nash equilibrium solutions are solved based on the nonlinear complementarity approach. In a simulated electricity market, the result can validate the feasibility of the model and adopted methodology and the rationality of the results by taking certain CHSs with multireservoir as an example. The negative influence of ASHS is analyzed, which shows that the characteristics of the hydropower system should be fully considered in the long-term bidding research. Future study aspects are also considered, which are presented as the key issues such as market assumptions and randomness.

Identification of critical source areas (CSAs) for non-point source (NPS) pollution is of great significance for environment governance and prevention. However, the CSAs are generally characterized as great spatial dispersion, and spatially heterogeneous precipitation has a great influence on the spatial distribution of nutrient yields. Therefore, we identify the CSAs for nutrient yields in an agricultural watershed of Northeast China at hydrological response units (HRUs) scale based on the Soil and Water Assessment Tool (SWAT), assess the impacts of spatially heterogeneity of precipitation on the identification of the CSAs, analyze the sensitivity of nutrient yields to precipitation by scenarios analysis method, and further identify priority management areas (PMAs) that have poor ability to retain nutrients. The results showed that the CSAs for nutrient yields identified by uniform precipitation showed greater fluctuation range and coverage area than actual precipitation; the major prevention areas of total nitrogen (TN) yield were mainly distributed in regions nearby main stem of lower reaches, while that of total phosphorus (TP) yield were mostly located in urban area nearby outlet of the watershed; the identification of the PMAs significantly decreased the CSAs for TN yield, whereas that for TP yield was no significant difference with the CSAs. This study could provide scientific guidance for the NPS pollution governance and prevention.

To investigate the monitoring history and long-term change trends in surface water quality in China since the reform and opening up, the history of surface water environment monitoring is summarized, including monitoring scope, monitoring methods, and technical requirements. Temporal and spatial patterns of surface water quality in China were analyzed based on the monitoring results. In the past 40 years, the monitoring targets for surface water quality have been continuously improved, the frequency of monitoring has become more science-based, and the monitoring indicators are now comprehensive. Overall, the temporal change trend in surface water quality has followed a “fluctuating changes stage—rapid deterioration stage—fluctuations stalemate stage—rapid improvement stage” pattern. However, the current regional surface water quality is still in a polluted status, and there is a gap between surface water quality status and the goal of building a well-off society. At present, China’s surface water pollution is prone to high numbers of incidents and the treatment of surface water pollution has entered a crucial stage. The potential for the continuous reduction of major pollutant discharges has become more challenging, and the marginal cost for pollution control has increased. It is very difficult to comprehensively solve the outstanding water environment problems. In addition to strengthening the existing work on surface water quality control, it is also necessary to strengthen the work of risk identification, early warning, and regulation implementation of the surface water environment. During the 14th year plan period (2021–2025), the overall planning on water resources, water ecology, and water quality will be implemented, and beautiful rivers and lakes will be created.

Introduction: Many studies have compared unicompartmental knee arthroplasty (UKA) with total knee arthroplasty (TKA) for knee osteoarthritis suggesting that both procedures had good clinical outcomes. However, there have been fewer studies comparing the mobile-bearing UKA (MB-UKA) and posterior cruciate ligament retaining TKA (CR-TKA) for patients with unicompartmental knee osteoarthritis. Thus, we explored the differences in outcomes and complications between the two cohorts.Methods: In this retrospective study, 41 patients who underwent MB-UKA and 40 who underwent CR-TKA in our institution were included. All patients were suffered from unicompartmental knee osteoarthritis. Patient demographics, preoperative and latest postoperative range of movement (ROM), Knee Society (KS) scores, and Forgotten Joint Score (FJS) were compared between the two cohorts. Additionally, complications, revisions, and 5-years survivorship were also analyzed.Results: The results showed MB-UKA patients had similar preoperative ROM and Knee Society pain (KSP), functional (KSF), and clinical (KSC) scores with CR-TKA patients (p = 0.104, p = 0.755, p = 0.32, p = 0.928, respectively). The mean follow-up for MB-UKA and CR-TKA groups was 3.4 and 3.7 years, respectively. Two MB-UKA and one CR-TKA patient required revision surgery. The latest postoperative KSF scores, ROM, FJS, and change in KSC scores and ROM were higher (p < 0.05) after MB-UKA, but the latest postoperative KSP, KSC, and change in KSF scores were equivalent between the two cohorts. There were no differences in complication, revision rates, and 5-year survivorship estimates.Conclusions: MB-UKA patients showed better functional outcomes and FJS, and higher ROM with similar survivorship compared with CR-TKA patients. MB-UKA should be considered as a primary treatment option for patients with unicompartmental knee osteoarthritis.Trial registration: researchregistry5032. Registered 23 July 2019, retrospectively registered

This study summarized the history of ambient air quality monitoring and air pollution prevention and control, and it analyzed the spatiotemporal patterns of ambient air pollutants during 1981–2017 in China. The results showed that monitoring of ambient air quality has changed dramatically in terms of determinants, sampling methods, monitoring extent, and evaluation basis during the previous four decades. Annual average concentrations of total suspended particulates, PM10 and SO2 have shown obvious decreasing trends during the studied period. These improvements have been closely related to the considerable efforts and various approaches undertaken to prevent and control air pollution. However, although policy implementation has been decisive and, at least in part, it has been enforced effectively, significant challenges remain. Air pollution control cannot be accomplished without a long-term strategy designed to achieve clean air in all parts of China.

Background The transforming growth factor β regulator 4 (TBRG4) has been proved to be involved in various types of tumor. However, its contribution in human osteosarcoma (OS) is still unclear. Patients and Methods In the present study, immunohistochemistry and quantitative real-time PCR were performed to investigate the expression of TBRG4 in OS tissues obtained from patients and three types of cell lines. The effect of TBRG4 knockdown using lentivirus on tumorigenesis was detected by CCK8, high-content screening analysis, colony formation assay and flow cytometric analysis. Bioinformatics analysis was operated to investigate related signaling pathways following TBRG4 knockdown. Results The results showed that the expression of TBRG4 increased significantly in OS tissues and MG63 cell line. TBRG4 knockdown inhibited cell proliferation, colony and tumor formation, while activating cell apoptosis. Ingenuity Pathway Analysis and Western blot assay further indicated that TBRG4 knockdown may regulate the proliferation of human MG63 cells through PI3K/Akt signaling pathway. Conclusion Our results suggest that TBRG4 may become a promising therapeutic target for the treatment of human OS.

Tibet and the Sichuan-Yunnan Tibetan area have enormous potential for hydropower development. Therefore, accelerating hydropower development in these areas can contribute to water resource utilisation and help relieve the poverty, which has also become a necessary choice of national strategic importance to comply with energy-saving, emission reduction, and ‘power transmission from west to east’ policies. Under existing policies, research has shown that the basic costs of electricity from the typical plants in Tibet and the Sichuan-Yunnan Tibetan area are high and uncompetitive, so that investment enthusiasm for hydropower companies will wane and water resource utilisation will be affected. In this study, we suggest policies to improve the competitiveness and sustainability of the hydropower development in the Tibet and Sichuan-Yunnan Tibetan areas; eventually, the water resources therein can be more effectively utilised. Research has indicated that drafted preferential policies can effectively decrease the cost price. Additionally, the hydropower industry in these areas should be incorporated into the national primary energy balance, forming a government-dominated market mechanism. This would consist of a mandatory market share of the hydropower transmitted from Tibet and the Sichuan-Yunnan Tibetan area and hydropower–carbon trade mechanism – the aim being to promote the consumption of hydropower across the nation.

China may require a long time to transition its power system from a planned one to a completely competitive market. Priority power generation (PPG), as a special type of power in the transitional period, is of great importance to incentivise power generation entities to participate in the market and promote power system reforms. However, the allocation of PPG currently relies excessively on the subjective decisions and experience of staff and lacks scientific basis and reasonable methods. Considering the case of Sichuan Province in China, this study proposed a PPG allocation method for reservoir power stations (RPSs) based on the principles of fairness, justice, and openness. First, RPSs were divided into categories based on the clustering results of many variable indicators that reflect the contribution and cost in aspects such as power generation, flood control, water supply, irrigation, emission reduction, grid peak shaving. Second, the random forest method was adopted to select the key indicators affecting the classification results. Then, the key indicators were weighted to obtain the priority index, and the PPG allocation was performed based on the priority index. Finally, the proposed method was used to allocate the PPG of RPSs in Sichuan in 2019. The results indicated that the allocation method based on the priority index is more conducive to increasing the market participation of RPSs than the original plan. In addition, it can save approximately 73 million yuan in electricity purchase costs for the grid.

Owing to the influence of uncontrollable factors (e.g., climate), wind and photovoltaic (PV) energy are highly fluctuating and undispatchable, thereby hindering their integration to the grid. To address this issue, complementary systems using hydropower as a regulating energy are gradually emerging. With the development of wind and PV power industries and the electricity spot market, wind and PV power subsidies are being reduced, and the bidding subjects are diverse. It is likely that wind, PV, and hydropower will participate in the market with the same quality and price. Wind–photovoltaic–hydropower complementary systems (WPHCSs) normally aim at minimum wind and PV power curtailment, which do not consider hydropower production aspects. This study considers the effect of complementary operation on hydropower in the context of energy indifference bidding in the future electricity spot market, establishes a comprehensive benefit index system to optimize WPHCS, and proposes a particle swarm optimization algorithm that introduces the dominant solution with an adjustable parameter to solve the maximizing comprehensive benefits of a complementary system model. Control experiments with different loads, storage capacities, inflows, and models were conducted to verify the superiority of the proposed model and to summarize the optimal operation rule of the complementary system. The results show that turbine efficiency is the main factor affecting the results, and the total benefit of the system could be improved by up to 69% comparing with the priority consumption of wind and the PV power model. This paper describes the WPHCS benefits more comprehensively, and the results can be used to improve the benefits of complementary systems.

It is difficult to find an algorithm to distribute specific reservoir releases to the floodgates of a hydropower plant in the flood season. In this study, based on a classification of floodgate combinations and the outflow from a hydropower plant, a floodgate table has been established. In order to provide a reasonable scheme for the distribution of releases to the floodgates, this paper summarises the principle of the distribution. A multi-step progressive optimality algorithm (MSPOA) is adopted for optimal floodgate operation in cascade reservoirs and applied to calculate the outflow from each reservoir of cascade reservoirs. Subsequently, according to the summarised principle, the method of bisection is used to search floodgate combinations from the floodgate table for the distribution of releases to the floodgates. To verify its feasibility, the proposed method is applied to optimal floodgate operation in a cascade reservoir system that has four hydropower plants on the Yalong River. A comparison of the application results of the progressive optimality algorithm and MSPOA methods shows that the proposed method can provide reasonable results for flood control and can distribute specific reservoir releases to the floodgates for each reservoir in the cascade reservoir system accurately.

For the spot electricity market, the quotation combining the hydropower stations is more resistant to uncertainties of runoff and spot price in market bidding. Therefore, it is of great significance to set up a spot quotation system for these hydropower stations. The paper first studied the fundamental characteristics of hydropower stations at different tiers, based on which the establishment of a quotation system of hydropower stations at different tiers and the bidding procedures were proposed. In addition, the paper investigated the joint bid model suitable for hydropower stations at different tiers based on cooperation between bidding stations. Finally, the paper established a coordinated management model and conflict-solving model for the quotation system of hydropower stations at different tiers, providing theoretical support for the system to take part in the spot electricity market and improve its marketing capabilities.

The stochasticity of photovoltaic (PV) generation output makes it necessary to smooth the output using other flexible power sources to realize the scale development of PV power. Small cascade hydropower stations (SCHSs) are also widely distributed in space, like PV generation. Therefore, it is proposed to utilize the regulation capability of SCHSs to complement PV generation. Targeting the maximization of the utilization rate of outgoing lines (utilization rate for short) of the system, the minimization of the curtailment rate, and the maximization of the minimum output within a time frame, a model for exploring the capability of SCHSs for regulating PV generation was established and solved by a hierarchical optimization method. By taking two small hydropower stations (the Mupo and Yangjiawan stations) on the Fabian River with a total installed capacity of 105 MW and the surrounding PV power source in China's Sichuan Province as examples, it was found that SCHSs can regulate a certain level of PV generation through the combined operation of cascade reservoirs and reduce the fluctuations and stochasticity of the PV generation output. The results have far-reaching significance on the large-scale development of PV generation.

Cascade hydropower stations have good regulation and storage capacity and they can be used as a regulatory and compensatory “medium” to compensate for the instability of wind–photovoltaic power generation. This paper presents a short-term multi-objective coordinated dispatching model based on wind–photovoltaic–hydro heterogeneous energy hybrid power generation. The multi-objectives of the model included accepting new energy for power generation to the greatest possible extent, tracing the load curve of the grid with minimum differences, and minimizing the discarded water volume of the cascade reservoirs. To reduce the complexity of the problem, the model was decomposed into two-stage optimization model and solved by using the firefly algorithm. This model was applied to a national-level wind–photovoltaic–hydro complementary power generation base in China. The research results verified the validity of the model and showed that it was feasible to compensate for the wind–photovoltaic power output fluctuation by the cascade hydropower stations and to supply power to the grid by bundling these three power sources. During this process, the cascade hydropower stations certainly made some sacrifices and increased the amount of discarded water. The new operational strategy proposed in this paper can promote the low-carbon power dispatching and optimization of the energy structure.

Mountain torrents and debris flows are rapid transport processes for soil and water materials in small watersheds in mountainous areas. They have a strong destructive power and often result in devastating natural disasters. Natural ecosystems can regulate natural disasters, reduce the risk of damage, increase the stability of disaster-prone environments and reduce the vulnerability of downstream areas. The upper reaches of the Minjiang River (URM) in Sichuan Province, China is a typical area prone to flood and debris flow disasters. An established scientific model was used to analyze land cover change in the URM to discover the optimum land use pattern. Based on the analysis of the pattern of temporal and spatial changes of ecosystems in the URM, the results showed that the amount of ecosystem change in the URM was small, and the overall change rate of ecosystems was only 1.7%. There was an obvious trend of landscape fragmentation in the whole URM region, and the change of ecosystems had clear regional differences. Human economic activities were the main reason for the changes in the spatial pattern of ecosystems from 1985 to 2013.

Background Antifibrinolytic agents such as tranexamic acid (TXA), epsilon aminocaproic acid (EACA), and aprotinin are widely used to reduce bleeding and the need for transfusion in cardiac, orthopaedic, and hepatic surgery. We aimed to assess the efficacy and safety of antifibrinolytic agents in total hip arthroplasty (THA). Methods A systematic literature search was performed using MEDLINE, PubMed, EMBASE, and Cochrane databases, as well as the reference lists of relevant articles. Only randomised controlled trials were eligible for this study. The weighted mean difference in blood loss, number of transfusions per patient, and the summary risk ratio of transfusion requirements and deep-vein thrombosis (DVT) were calculated in the antifibrinolytic agents-treated and control groups. Results A total of 28 randomised controlled trials involving 2,131 patients were included. Patients receiving antifibrinolytic agents had a reduced total blood loss by a mean of 389.14 ml (95% CI, −483.05 to −295.23), and the number of blood transfusions per patient by 0.65 units (95% CI, −1.19 to −0.12). Antifibrinolytic agents led to a significant reduction in transfusion requirements (RR 0.55; 95% CI, 0.43 to 0.70) and no increase in the risk of DVT (RR 0.85; 95% CI, 0.51 to 1.42). Conclusions Our meta-analysis demonstrated that antifibrinolytic agents significantly reduce blood loss and blood transfusion requirements while not increasing the risk of DVT in patients undergoing total hip arthroplasty.

An operational model that analyzes the relationship between annual energy output and year-end stored energy of a reservoir system was developed and used for determining the optimal year-end water level of a multi-year regulating storage reservoir. The model accounts for the capacity benefit of a multi-annual storage plant and was validated using the case of the Longyangxia reservoir in the upper reaches of the Yellow River, China. The critical elements for determining the optimal year-end water level for multi-year regulating storage reservoirs were revealed through analysis of the impacts of runoff and year-start water level on year-end water level. Simulated operational results from the model were compared with practical operational results for the Longyangxia reservoir system from 1990–2012. A comparison shows that the operating mode for Longyangxia reservoir (after 2006) achieved significant improvement versus before 2006, in making the reservoir run at a higher water level and increasing benefits. In addition, our study indicates that the model can be effectively used for multi-year regulating storage reservoir operation.

Based on the analysis of point source (PS) and non-point source (NPS) pollution emission characteristics of Dianchi Lake Basin, pollution load into the lake simulation models was constructed; the result should be useful for eutrophication researchers. The PS and NPS pollution load calculation results were added come exogenous pollution load into Dianchi Lake. Exogenous pollution load into Dianchi lake chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) were 32876.86, 6571.64 and 429.37 t in 1990, respectively; were 33780.66, 10326.64 and 654.59 t in 2005, respectively; were 37717.00, 8597.01 and 546.48 t in 2012, respectively. Exogenous pollution load of Dianchi Lake temporal evolution and spatial distribution changing characteristics were analyzed that TN and TP pollution load were increased from 1990 to 2005, and they were decreased from 2005 to 2012, COD pollution load were increased in both periods. July or August was the most pollution load into the lake among months in 1990, 2005 and 2012. PS pollution was mainly concentrated in the northern area and the inside of Wuhua District and Guandu District. NPS COD pollution output increased was mainly the south of the northern area in Dianchi Lake Basin and reduced were mainly the north of the northern area, eastern area, western area and southern area; TN output of NPS increased in most regions, and only the central northern area had reduced regional distribution; TP output of NPS decreased mainly in the north of northern area, and increased in most other regions of the Basin from 1990 to 2012. The result should be meaningful to zoning control and classifying control of exogenous pollutants into the Lake.