Choosing R&D or advertising for competing firms in uncertain market

Purpose: R&D and advertising have become important means to enhance the competitiveness of firms’ products. Design an appropriate model to help the firm to make the right choice is value in supply chain. Design/methodology/approach: In considering that whether the market is completely covered or not, we build the strategy selection model for R&D and advertising for two competing firms and solve the optimal strategy. Findings and Originality/value: The research results show that when a firm does not take any measures to enhance competitiveness, another firm will neither. However when one takes measures to improve the competitiveness, another will do so, also. When two firms must choose one measure to improve the competitiveness, either in full-covered market or not full-covered market, the two firms will not choose to do advertising in step, even if the firms do not have to pay additional cost in advertising. Originality/value: In the game model, the firm could compare the own profit in different strategies. According to the above model, the firm choose the right strategy to make the profit maximize in a vertically differentiated market. And when the firm make the choice, it must think about other primary elements such as market.Peer Reviewe

Behavior Coordination in E-commerce Supply Chains

This paper studies the behavior coordination of members in e-commerce supply chains with cooperative game theory. Under the environment of e-commerce, the retailers and the supplier can maximize their profits through the cooperation with the information provider. We study this cooperation by means of cooperative game theory and emphasize the importance of the information provider in the cooperation. We give a core allocation and a solution for these games

A Consumption Characteristics Model of the Customer in Incomplete Information Situation in E-commerce

Customers are the important strategic resources for the companies in E-commerce market, understanding customer’s consumption characteristics as soon as possible becomes more important for companies to win in a competitive online market. The paper tries to construct a model to represent the customer’s consumption characteristics based on a little information about this customer’s purchase behavior. In the model, the attributive combinations and their orderings of the products were found to reflect the customer’s purchase decision. An example arranged in the paper illustrates that the model can be a good tool for the companies to understand a customer or a group of similar customers’ consumption characteristics

An Impulsive Three-Species Model with Square Root Functional Response and Mutual Interference of Predator

An impulsive two-prey and one-predator model with square root functional responses, mutual interference, and integrated pest management is constructed. By using techniques of impulsive perturbations, comparison theorem, and Floquet theory, the existence and global asymptotic stability of prey-eradication periodic solution are investigated. We use some methods and sufficient conditions to prove the permanence of the system which involve multiple Lyapunov functions and differential comparison theorem. Numerical simulations are given to portray the complex behaviors of this system. Finally, we analyze the biological meanings of these results and give some suggestions for feasible control strategies

Analysis of an Impulsive One-Predator and Two-Prey System with Stage-Structure and Generalized Functional Response

An impulsive one-predator and two-prey system with stage-structure and generalized functional response is proposed and analyzed. By reasonable assumption and theoretical analysis, we obtain conditions for the existence and global attractivity of the predator-extinction periodic solution. Sufficient conditions for the permanence of this system are established via impulsive differential comparison theorem. Furthermore, abundant results of numerical simulations are given by choosing two different and concrete functional responses, which indicate that impulsive effects, stage-structure, and functional responses are vital to the dynamical properties of this system. Finally, the biological meanings of the main results and some control strategies are given

Association of Blood Pressure With Stroke Risk, Stratified by Age and Stroke Type, in a Low-Income Population in China: A 27-Year Prospective Cohort Study

Association of stroke risk with new blood pressure criterion 2017 is unknown in China. We assessed the association between blood pressure (BP) values and stroke risk in a low-income population in Tianjin, China. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) values were categorized into five strata and strokes were recorded as stroke, ischemic stroke, and hemorrhagic stroke. Stroke risk was analyzed according to blood pressure stratum using Cox regression analysis. Overall, 4,017 residents (age, ≥18 years) were included in this prospective cohort study. Over a 27-year follow-up period (total, 86,515.78 person-years), 638 participants experienced first-ever strokes. The stroke risk was higher among individuals with SBPs ≥140 mmHg or DBPs ≥90 mmHg than among those with SBPs < 130 mmHg or DBPs < 80 mmHg (reference group), after adjusting for covariates. However, hemorrhagic stroke risk increased only in participants with SBPs ≥160 mmHg. The stroke risk increased for individuals < 65-years-old having BP values ≥130/80 mmHg and for individuals ≥65-years-old with BP values ≥160/90 mmHg. To reduce the stroke burden in China, target BP goals must be established for adults, with different targets for the middle-aged and the elderly segments of the population. These results are very important for guiding clinical practice and may be generalized to other developing countries experiencing rapid economic development and where transitions in the spectrum of prevalent diseases have occurred

Determinants of Developing Stroke Among Low-Income, Rural Residents: A 27-Year Population-Based, Prospective Cohort Study in Northern China

Although strokes are the leading cause of death and disability in many countries, China still lacks long-term monitoring data on stroke incidence and risk factors. This study explored stroke risk factors in a low-income, rural population in China. The study population was derived from the Tianjin Brain Study, a population-based stroke monitoring study that began in 1985. This study documented the demographic characteristics, past medical histories, and personal lifestyles of the study participants. In addition, physical examinations, including measurements of blood pressure (BP), height, and weight, were performed. Hazard ratios (HRs) were estimated for the risk factors for all subtypes of stroke using multivariate Cox regression analyses. During the study with mean following-up time of 23.16 years, 3906 individuals were recruited at baseline, and during 27 years of follow-up, 638 strokes were documented. The multivariate Cox regression analyses revealed a positive correlation between age and stroke incidence. Limited education was associated with a 1.9-fold increase in stroke risk (lowest vs. highest education level). Stroke risk was higher among former smokers than among current smokers (HR, 1.8 vs. 1.6; both, P < 0.05). Moreover, stroke risk was significantly associated with sex (HR, 1.8), former alcohol drinking (HR, 2.7), baseline hypertension (HR, 3.1), and overweight (HR, 1.3). In conclusion, this study identified uncontrollable (sex and age) and controllable (education, smoking, alcohol drinking, hypertension, and overweight) risk factors for stroke in a low-income, rural population in China. Therefore, it is critical to control BP and weight effectively, advocate cessation of smoking/alcohol drinking, and enhance the education level in this population to prevent increase in the burden of stroke in China

Sex Differences in the Prevalence, Awareness, Treatment, and Control of Diabetes Mellitus Among Adults Aged 45 Years and Older in Rural Areas of Northern China: A Cross-Sectional, Population-Based Study

Aims: Diabetes mellitus (DM) has reached epidemic proportions among adults worldwide, with China having the world's largest population of individuals with the disease. Although the consequences of low rates of awareness, treatment, and control of DM are understood, sex-related differences in these rates remain unknown. We assessed sex-related differences in the prevalence, awareness, treatment, and control of DM in a low-income, rural population in China.Materials and Methods: Individuals ≥45 years old without cardiovascular disease were recruited into this study. The prevalence, awareness, treatment, and control of DM in both men and women were assessed after accounting for age, educational level, body mass index, and blood pressure.Results: A total of 3,725 participants (women, 58.8%) were included. A male preponderance in the prevalence of DM was found among individuals aged 45–54 years, whereas there was a female preponderance among patients aged 65–74 years and among those who were illiterate. Among individuals with >6 years of formal education, overweight individuals, and normotensive individuals, there was greater DM awareness among women than among men. There was also a higher DM treatment rate among overweight women than among overweight men. However, better disease control was observed among men than among women for individuals aged 55–64-years, those with 1–6 years of education, and those with stage II hypertension.Conclusions: These results suggest that DM awareness should be improved among men and that regular DM screening should be implemented for men, especially young men. In addition, disease education and management should be strengthened for elderly women, especially those with low levels of education. Further studies are necessary to explore this situation among a representative population sample in China in order to establish a valid protocol against DM

Experimental study on the radiant heat flux of wall-attached fire plume generated by rectangular sources

Radiant heat flux of fire plume is an essential parameter indicating the hazards of a fire. In this work, fire experiments of a wall-attached fire with different aspect ratios were conducted. In addition, the effect of the sidewall on mean flame height and radiant heat flux of the rectangular fire was investigated. The sidewall causes a decrease in air entrainment; therefore, the mean flame height is observed to increase. The radiant heat flux increased owing to the increase in flame height and thermal radiation from the heated sidewall. Experimental results of the mean flame height are consistent with those predicted by an existing model. This validated the reliability of the experimental setup for a rectangular wall-attached fire. Furthermore, a model based on the increase in flame height and thermal radiation from the heated sidewall was developed to estimate the radiant heat flux from a rectangular wall-attached fire. The error in prediction was less than 15% for this model