WeproposeanODEapproachtosolvingmultiplechoicepolynomialprogram- ming (MCPP) after assuming that the optimum point can be approximated by the ex- pected value of so-called thermal equilibrium as usually did in simulated annealing. The explicit form of the feasible region and the affine property of the objective function are both fully exploited in transforming an MCPP problem into an ODE system. We also show theoretically that a local optimum of the former can be obtained from an equilib- rium point of the latter. Numerical experiments on two typical combinatorial problems, MAX-k-CUT and the calculation of star discrepancy, demonstrate the validity of the ODE approach, and the resulting approximate solutions are of comparable quality to those obtained by the state-of-the-art heuristic algorithms but with much less cost. When compared with the numerical results obtained by using Gurobi to solve MCPP directly, our ODE approach is able to produce approximate solutions of better quality in most instances. This paper also serves as the first attempt to use a continuous algorithm for approximating the star discrepancy.
We investigate how exposure to the One-Child Policy (OCP) during early adulthood affects marriage and fertility in China. Exploring fertility penalties across provinces over time and the different implementations by ethnicity, we show that the OCP significantly increases the unmarried rate among the Han ethnicity but not among the minorities. The OCP increases Han-minority marriages in regions where Han-minority couples are allowed for an additional child, but the impact is smaller in other regions. Finally, the deadweight loss caused by lower fertility accounts for 10 percent of annual household incomes, and policy-induced fewer marriages contribute to 30 percent of the fertility decline.
Recent advances on time series forecasting mainly focus on improving the forecasting models themselves. However, when the time series data suffer from potential structural breaks or concept drifts, the forecasting performance might be significantly reduced. In this paper, we introduce a novel approach called Optimal Starting Point Time Series Forecast (OSP-TSP) for optimal forecasting, which can be combined with existing time series forecasting models. By adjusting the sequence length via leveraging the XGBoost and LightGBM models, the proposed approach can determine the optimal starting point (OSP) of the time series and then enhance the prediction performances of the base forecasting models. To illustrate the effectiveness of the proposed approach, comprehensive empirical analysis have been conducted on the M4 dataset and other real world datasets. Empirical results indicate that predictions based on the OSP-TSP approach consistently outperform those using the complete time series dataset. Moreover, comparison results reveals that combining our approach with existing forecasting models can achieve better prediction accuracy, which also reflect the advantages of the proposed approach.
The reactive substance consisting manganese oxides (MnOx) and solid carbon have been reported to be effective in polishing secondary wastewater; however, the treatment characteristics and mechanism remains limited. In this study, MnOx/carbon (Mn-C) composites were applied in biofilters to evaluate simultaneous removal of nitrate and sulfamethoxazole (SMX), with the single carbon composites as control. Results showed that the effluent concentrations of NO3 –N and SMX were below 2.87 mg L- 1 and 7.97 mu g L- 1 under hydraulic retention time (HRT) of 6 h. The intermittent aeration optimized Mn cycle with treatment performance improved under lower HRT and Mn(II) accumulation decreased. Mn-C composites could reduce the emission of N2O, CO2 and CH4. The dominant genera gradually evolved from fermentation to glycogen aggregation, and from heterotrophic/sulfur autotrophic to heterotrophic denitrifiers by intracellular substance and manganese autotrophic/heterotrophic bacteria. Microbial network analysis indicated higher antagonism, lower modularity and shorter average path among microbes in Mn-C biofilters, which highlighted microbial differentiation and faster electron transfer. Improved functions of denitrification and Mn respiration, and the increasing genes encoding electron transfer chain, including NADH dehydrogenase, Cytc and ubiquinone, further elucidated the superiority of Mn-C com- posites. These results improved our understanding of Mn-C composites application in low-carbon wastewater treatment.
This study examines how overconfidence shapes individuals' preference for redistribution. We contend that overconfidence inflates individuals' income expectations, which reduces the perceived benefits of redistribution for these individuals and thereby weakens their preference for such policies. Using data from the 2014 China Family Panel Studies, we find that overconfident individuals are more confident in their future life and exhibit less concerns for economic inequality, healthcare, and social security issues—key proxies for preference for redistribution. These results are more pronounced among less wealthy individuals. In addition, our results remain unchanged after controlling for individuals' trust in government and risk preference. These findings highlight the role of biased belief in shaping individuals’ attitude toward redistribution, offering new insights for discussions on redistributive policies.
Does increasing descriptive representation enhance substantive representation? While ethnic minorities are generally underrepresented in legislatures worldwide, they are overrepresented in China’s National People’s Congress. We show that overrepresentation of ethnic legislators does not result in greater substantive representation. Compared to their Han counterparts, ethnic minority legislators are less likely to sponsor bills, show no significant difference in submitting policy suggestions, and are reticent to propose legislation on ethnic issues. They face challenges in mobilizing sufficient signatures for bill sponsorship within delegations and in building cross-delegation policy coalitions. Ethnic fragmentation may hinder their ability to advance the policy agenda. Our findings suggest that institutional constraints and collective action problems may hinder ethnic legislators from achieving substantive representation.
Mineral crystallization is central to myriad natural processes from the formation of snowflakes to stalagmites, but the molecularscale mechanisms are often far more complex than models reflect. Feedbacks between the hydro-, bio-, and geo-spheres drive complex crystallization processes that challenge our ability to observe and quantify them, motivating an expansion of crystallization theories. In this article, we discuss how the driving forces and timescales of nucleation are influenced by factors ranging from simple geometric confinement to distinct interfacial solution structures involving solvent organization, electrical double layers, and surface charging effects. Taken together, these ubiquitous natural phenomena can preserve metastable intermediates, drive precipitation of undersaturated phases, and modulate crystallization in time and space.