Discreet investors exert greater influence on cooperation in the public goods game

This paper studies the evolutionary process of cooperative behavior in a public goods game model with heterogeneous investment strategies in square lattices.In the proposed model,players are divided into defectors,cooperators and discreet investors.Among these,defectors do not participate in investing,discreet investors make heterogeneous investments based on the investment behavior and cooperation value of their neighbors,and cooperators invest equally in each neighbor.In real life,heterogeneous investment is often accompanied by time or economic costs.The discreet investors in this paper pay a certain price to obtain their neighbors'investment behavior and cooperation value,which quantifies the time and economic costs of the heterogeneous investment process.The results of Monte Carlo simulation experiments in this study show that discreet investors can effectively resist the invasion of the defectors,form a stable cooperative group and expand the cooperative advantage in evolution.However,when discreet investors pay too high a price,they lose their strategic advantage.The results in this paper help us understand the role of heterogeneous investment in promoting and maintaining human social cooperation.

Influence of dissolved oxygen content on oxidative stability of linked polymer solution

The influence of dissolved oxygen content on the oxidative stability of a linked polymer solution (LPS) was studied by micro-filtration, dynamic light scattering and viscosity measurements. The results showed that at the same temperature, the degree of the oxidative degradation of the LPS increased and the rapidity of the oxidative degradation was accelerated with the increase of the dissolved oxygen content. Consequently, the size of linked polymer coils (LPCs) of the LPS became small, and the plugging capability of the LPS decreased. At a fixed content of dissolved oxygen, with increasing degradation temperature, almost the same results were observed, namely, an increased degree of oxidative degradation, accelerated rapidity of the oxidative degradation and decreased plugging capacity, with decreased oxidative stability of LPS. At 90 °C, in the presence of oxygen, LPS lost its plugging capability after having been degraded for a period of time. But at 40 °C, LPS with low dissolved oxygen content could be stable for a long time. The decreased plugging ability of LPS after oxidative degradation is mainly caused by the decreased size and number of the LPCs due to the breaking of hydrolyzed polyacrylamide (HPAM) molecule segments and the structural changing of HPAM molecules.

Nonlinear vibration of iced cable under wind excitation using three-degree-of-freedom model

High-voltage transmission line possesses a typical suspended cable structure that produces ice in harsh weather.Moreover,transversely galloping will be excited due to the irregular structure resulting from the alternation of lift force and drag force.In this paper,the nonlinear dynamics and internal resonance of an iced cable under wind excitation are investigated.Considering the excitation caused by pulsed wind and the movement of the support,the nonlinear governing equations of motion of the iced cable are established using a three-degree-of-freedom model based on Hamilton's principle.By the Galerkin method,the partial differential equations are then discretized into ordinary differential equations.The method of multiple scales is then used to obtain the averaged equations of the iced cable,and the principal parametric resonance-1/2 subharmonic resonance and the 2:1 internal resonance are considered.The numerical simulations are performed to investigate the dynamic response of the iced cable.It is found that there exist periodic,multi-periodic,and chaotic motions of the iced cable subjected to wind excitation.

Anti-microbial Effects In Vitro and In Vivo of Alstonia scholaris

Alstonia scholaris could be used as a traditional medicinal plant in China for the treatment of acute respiratory,which might be caused by respiratory tract infections.The investigation tested the anti-infective effects of total alkaloids extract(TA)from leaves of A.scholaris,and as a result,TA inhibited herpes simplex virus type 1(HSV-1),respiratory syncytial virus(RSV)and influenza A virus(H1N1)in vitro respectively.In addition,the survival days of mice were prolonged,and the lung weights and mortality of mice were decreased significantly,after oral administrated TA in H1N1 and beta-hemolytic streptococcus infectious models in vivo respectively.The finding supported partly the traditional usage of A.scholaris in the treatment of respiratory infections.

Changes of serum TNF-alpha, IL-2 and IL-13 in patients with rheumatoid arthritis

Objective:To explore the changes of serum TNF-alpha, IL-2 and IL-13 in patients with rheumatoid arthritis (RA).Methods: A total of 60 patients with rheumatoid arthritis admitted to our hospital from December 2016 to December 2017 were selected as the observation group, and another 60 healthy people in the same period were selected as the control group. Enzyme-linked immunosorbent assay (ELISA) double antibody sandwich method was used to detect the changes of serum TNF-α, IL-2 and IL-13 in the observation group before and after treatment, and was correlated with rheumatoid arthritis disease activity index, plasma ESR, CRP level and DAS28 score.Results:before treatment, serum TNF-α, IL-2 alpha and IL-13 were significantly higher than those in the control group, the observation group of serum TNF-α, IL-2 and IL-13 levels were significantly lower than those before treatment, and compared with the control group, the difference was not statistically significant. Before treatment, the changes of serum TNF-α alpha, IL-2 and IL-13 during the onset of rheumatoid arthritis were positively correlated with the level of plasma ESR, CRP and DAS28.Conclusions:the serum levels of TNF-α, IL-2 and IL-13 in rheumatoid arthritis patients are significantly increased, and are closely related to the activity of rheumatoid arthritis. Patients can be effectively improved after treatment, which is worthy of clinical reference.

Fracture mechanism of a laminated aluminum alloy plate during ballistic impact

The multilayered 7XXX series aluminum alloy was impacted by 7.62 mm ogival projectiles at velocities ranging from 787 to 851m·s^（-1）. The deformed microstructure under various impacting velocities and fracture surfaces of different sections were investigated at different physical scales to determine the process of failure.Optical microscopy（OM）,electron back-scattered diffraction（EBSD） and scanning electron microscopy（SEM） were used in the investigation. The results show that crater is constrained in the 7B52 front layer and two types of adiabatic shear bands which are transformed bands and deformed bands and different types of cracks are observed.Spall fracture is the significant failure mode of 7B52 front layer, and the resulting delamination leads to the presence of bending tensile fracture instead of the shear plugging.The ductile 7A01 layer blunts and deflects the spall crack tips, preventing the targets from full spall, and induces a constraint of 7A52 rear layer. The level of the constraint determines different fracture modes of 7A52 layer,accounting for the asymmetry of damage.

Mechanical Assembly Packing Problem Using Joint Constraints

The three-dimensional packing problem is generally on how to pack a set of models into a given bounding box using the smallest packaging volume. It is known as an NP-hard problem. When discussing the packing problem in mechanical field, the space utilization of a mechanism is low due to the constraint of mechanical joints between different mechanical parts. Although such a situation can be improved by breaking the mechanism into components at every joint, it burdens the user when reassembling the mechanism and may also reduce the service life of mechanical parts. In this paper, we propose a novel mechanism packing algorithm that deliberately considers the DOFs （degrees of freedom） of mechanical joints. With this algorithm, we construct the solution space according to each joint. While building the search tree of the splitting scheme, we do not break the joint, but move the joint. Therefore, the algorithm proposed in this paper just requires the minimal number of splits to meet the goal of space utilization. Numerical examples show that the proposed method is convenient and efficient to pack three-dimensional models into a given bounding box with high space utilization.