Risk Factors of Postoperative Cerebrospinal Fluid Leak After Craniovertebral Junction Anomalies Surgery: A Case-Control Study

Objective To identify potential risk factors for cerebrospinal fluid (CSF) leakage after craniovertebral junction (CVJ) anomaly surgery and to provide a reference for clinical practice. Methods Sixty-six patients who underwent elective CVJ anomaly surgery during a 6-year period (April 2013 to September 2019) were retrospectively included. Research data were collected from the patients’ medical records and imaging systems. Patients were divided into CSF leak and no CSF leak groups. Univariate tests were performed to identify potential risk factors. For statistically significant variables in the univariate tests, a logistic regression test was used to identify independent risk factors for CSF leakage. Results The overall prevalence of CSF leakage was 13.64%. Univariate tests showed that a basion-dental interval (BDI) > 10 mm and occipitalized atlas had significant intergroup differences (p 10 mm was an independent risk factor for CSF leakage, and patients with CVJ anomalies with a BDI > 10 mm were more likely to have postoperative CSF leaks (odds ratio, 14.67; 95% confidence interval, 1.48–30.88; p = 0.004). Conclusion It is necessary to maintain vigilance during CVJ anomaly surgery in patients with a preoperative BDI > 10 mm to avoid postoperative CSF leaks

Competition and cooperation models for dynamic pricing of perishable products in a two-echelon supply chain

This paper considers a two-level supply chain involving a supplier and a retailer. The retailer sells perishable products to consumers over a finite time horizon, and the demand is driven by a price-and-utility function. First, we study the noncooperative problem, which is formulated by a Stackelberg model. It is shown that the optimal pricing strategy of the retailer is to reduce a constant amount on the price at the beginning of each stage. Second, we examine the cooperative problem, in which the supplier and the retailer jointly price the product. Maximum selling cycle lengths of the two situations are obtained by analyzing the reasonability of the sales price. We demonstrate that the selling cycle length is extended by cooperation. Moreover, we show that they lower the sales price in the cooperative case so as to maximize the total profit. Meanwhile, an allocation method is provided based on the proportion

Tripartite game models in a dual-channel supply chain: competition and cooperation

This paper considers tripartite games in a dual-channel supply chain which involves a manufacturer, an offline retailer and an online retailer. Both competition and cooperation issues are analyzed. In the competition model, a Stackelberg game between the manufacturer and two retailers and a Bertrand game between two retailers occur simultaneously. It is shown that the channel which attracts more consumers’ purchase preference is charged a higher wholesale price and it meanwhile declares a higher sales price. In the presence of revenue sharing, cooperation issues between the three participants are studied and the change of the revenue of each participant is analyzed when partial cooperation exists. Further, the definition of the optimum two-player coalition is proposed. We demonstrate that the channel which attracts more preference of consumers is definitely in the optimum coalition. The structure of the two-player coalition is analyzed. Finally, under revenue sharing and cost apportionments, the change of each participant’s profit is examined

Production and Pricing Strategies of Energy-Saving Products in the Presence of Duopolistic Manufacturers

This paper considers optimal production and pricing strategies of energy-saving products in the presence of duopolistic manufacturers. First, we analyze the free competition case by a Bertrand game. A sufficient condition for guaranteeing the existence and the uniqueness of the equilibrium solution is proposed. The change rate of the benefit function of environment with regard to purchasing preference proportions is examined. Second, we investigate the case in the presence of energy-saving incentive. A two-layer decision model is constructed by considering the decision order of each participant. Optimal strategies between the two cases are compared. We provide theoretical foundations for the government to formulate policies of energy-saving incentive under a financial budget constraint. Finally, a numerical example is presented to verify the obtained conclusions and make some supplements

Study on Multi-Depot Collaborative Transportation Problem of Milk-Run Pattern

Analyze the relevance between Milk Run mode and collaborative transportation problem, put forward collaborative transportation problem of multiple-depot on Milk Run mode under the supply and demand separate nodes, consider the value of transport and transport costs, introduce the concept of node - arc flow, by comparing the size of traffic flow determine nodes collection, and then constructed multi-transport model of the problem. Considering one-way pickup and delivery closed, construct two-stage algorithm model, use dynamic programming recursive solution to determine the best route to pick up, and then solving delivery routing problem with different start and return point based on geometric method of Cosine. Finally use a numerical example illustrates the effectiveness of the algorithm and reasonable model

Study on Multi-Depot Collaborative Transportation Problem of Milk-Run Pattern

Analyze the relevance between Milk Run mode and collaborative transportation problem, put forward collaborative transportation problem of multiple-depot on Milk Run mode under the supply and demand separate nodes, consider the value of transport and transport costs, introduce the concept of node - arc flow, by comparing the size of traffic flow determine nodes collection, and then constructed multi-transport model of the problem. Considering one-way pickup and delivery closed, construct two-stage algorithm model, use dynamic programming recursive solution to determine the best route to pick up, and then solving delivery routing problem with different start and return point based on geometric method of Cosine. Finally use a numerical example illustrates the effectiveness of the algorithm and reasonable model

Pricing strategies for new product and remanufactured product considering emission sensitive demand.

With the rapidly increasing concern on environmental pollution and resource shortage, remanufactured products attract many attentions. In order to determine the optimal production and pricing strategy, we construct decision models for both single-product market and mixed-product market. Consumers' different preferences for new products and remanufactured products are considered. First, we construct pricing models for a single-product market, and achieve a judging condition to determine the optimal strategy. Second, we develop a pricing model for a multiple-product market and put forward a suppose to show that the multiple-product strategy is not always optimal. Finally, numerical illustrations are designed to examine the impacts of the two crucial factors and obtain the dominant regions for each strategy. By introducing an emission sensitive demand, we show the superiority of the remanufactured product when the extra demand attracted by the emission saving is large