This paper presents a novel method for analyzing the economic and collaborative interactions among nations in the context of climate change. Specifically, a two-stage game-theoretic model is ...proposed, where players’ initial resources (heterogeneous endowments) are determined by a public goods game (first-stage) and a collective risk dilemma is subsequently played (second-stage). We establish the Nash equilibria for the proposed game model and provide numerical analysis results accordingly. We then explore the dynamics of the game in an evolutionary process, dividing the population into groups of fixed size. Our findings indicate that the scenario with high collective risk and low required donation is most conducive to cooperation, while smaller groups and populations are more likely to exhibit cooperative behavior. Moreover, both numerical analysis and simulation results demonstrate that a higher first-stage profit rate enhances cooperation. Overall, our study sheds light on the factors that facilitate cooperation among multiple heterogeneously endowed participants facing collective risk. We hope that our proposed model and results can contribute to the development of solutions for addressing the challenges posed by global issues such as climate change.
•New game-theoretical method models interactions among nations facing global risks.•A two-stage game model considers endogenously generated heterogeneous endowments.•Nash equilibria and evolutionary dynamics of the game are studied.•Factors favoring cooperation are given with theoretical/numerical/simulation results.
MicroRNAs (miRNAs) are endogenous small noncoding RNAs that regulate gene expression with functional links to tumorigenesis. Hepatocellular carcinoma (HCC) is the most common type of liver cancer, ...and it is heterogeneous in clinical outcomes and biological activities. Recently, we have identified a subset of highly invasive epithelial cell adhesion molecule (EpCAM)+ HCC cells from alpha‐fetoprotein (AFP)+ tumors with cancer stem/progenitor cell features, that is, the abilities to self‐renew, differentiate, and initiate aggressive tumors in vivo. Here, using a global microarray‐based miRNA profiling approach followed by validation with quantitative reverse transcription polymerase chain reaction, we have demonstrated that conserved miR‐181 family members were up‐regulated in EpCAM+AFP+ HCCs and in EpCAM+ HCC cells isolated from AFP+ tumors. Moreover, miR‐181 family members were highly expressed in embryonic livers and in isolated hepatic stem cells. Importantly, inhibition of miR‐181 led to a reduction in EpCAM+ HCC cell quantity and tumor initiating ability, whereas exogenous miR‐181 expression in HCC cells resulted in an enrichment of EpCAM+ HCC cells. We have found that miR‐181 could directly target hepatic transcriptional regulators of differentiation (for example, caudal type homeobox transcription factor 2 CDX2 and GATA binding protein 6 GATA6) and an inhibitor of Wnt/β‐catenin signaling (nemo‐like kinase NLK). Taken together, our results define a novel regulatory link between miR‐181s and human EpCAM+ liver cancer stem/progenitor cells and imply that molecular targeting of miR‐181 may eradicate HCC. (HEPATOLOGY 2009.)
Compared with the mandatory personal carbon trading, mechanisms that encourage individuals to voluntarily participate in carbon emission reduction are more easily accepted, such as the CGSP (Carbon ...Generalized System of Preferences) project in Guangdong Province, China. Carbon emission reduction, as a joint effort of multiple generations, involves interest conflicts between individuals and groups in one single generation, as well as multigenerational conflicts. By establishing the interaction between local environmental quality and individual returns, we build a public goods game with environmental feedback to simulate ecological and social coevolution. In this game with the CGSP mechanism, cooperators who reduce carbon emissions receive carbon credits, with which they can exchange for welfare funds to invest in environmental protection (denoted as AC) or for goods to improve their personal payoffs (BC). Individuals who do not contribute anything to improve the environment are called defectors (D). To study the impact of CGSP as an external incentive mechanism on cooperation, we explore the stationary states of three systems. In addition, we study the mechanisms behind some phases and phase transitions by monitoring the spatial distribution of strategies and the environmental quality of each region. The results show that a higher subsidy is not always better, whether cooperators exchange carbon credits for goods or welfare funds. Furthermore, ACs can effectively improve the spatial competitiveness of BC clusters, but BCs as ‘second-order free-riders’ can inhibit the spread of ACs. Indirect territorial competition between two types of cooperators can solve such a ‘second-order social dilemma’.
Punishment has traditionally been considered a more effective mechanism to promote cooperation than reward, but this is not necessarily the case if they are driven by inequity aversion (IA). A ...complete sense of fairness includes first-order and second-order IAs which refer to protests against advantageous and disadvantageous inequity, respectively. In this paper, such protests refer to the punishment and reward in payoff. To study the effect of IAs on human cooperation, we model a four-strategy system in spatial public goods game (PGG) with cooperators (Cs), first-order and second-order inequity-averse individuals (FIAs and SIAs), as well as defectors (Ds). The phase diagrams of the system illustrate that the presence of IAs can improve the cooperation level of population, and the effectiveness of different types of IAs are affected by several factors. Through the exploration of some phases and phase transitions, we conclude that a higher r (synergy factor) improves the competitiveness of SIAs more than that of FIAs, while a higher α (the factor of punishment and reward costs) undermines the cooperation promoting effect of FIAs more than that of SIAs. Such results are mainly related to the different spread patterns of their clusters. Unexpectedly, the increase of β (the factor of punishment and reward intensity) sometimes has a positive effect on the spread of defectors, which is attributed to the emergence of the self-organizing cyclic state among Cs, SIAs and Ds. Furthermore, indirect territorial competition can be observed for a high r, where Cs, FIAs and SIAs compete separately with Ds, and SIAs are more competitive than FIAs as a result.
Although cooperative behavior is ubiquitous in biological and social systems, the causes and mechanisms of cooperation are a basic problem in evolutionary theory. The snowdrift game is considered as ...an effective evolutionary game model to describe cooperative behavior in a competitive situation. Thus, this paper studies the evolutionary dynamics of cooperative behavior in multi-player snowdrift games. This work establishes a stochastic two-strategy multi-player snowdrift game based on the Wright-Fisher (W-F) update process. Next, a specific analytical expression for fixation probabilities of cooperation and defection is considered, and the conditions under which cooperative strategies take root in a population and become an evolutionarily stable strategy are given. Finally, the relationships between the fixation probability of cooperation and each parameter involved in the game are obtained via simulation analysis. A simulation analysis reveals that the fixation probability of cooperation decreases with selection intensity, the number of players playing in multi-player snowdrift games, and population size but increases with the benefit-cost ratio. The present work promotes an understanding of the evolutionary dynamics of cooperative behavior and the theory of multi-player snowdrift games with the W-F update process.
•A two-strategy multi-player snowdrift game with a W-F process is established.•The concrete analytic expression of the fixation probability is solved.•The conditions under which a strategy takes root and becomes ESS are given.•The relationships between fixation probability and each parameter are obtained.
A simple yet effective method was developed for generating an electrocatalyst for oxygen reduction reaction by deposited MoS2 sheets on nitrogen-doped graphene (NG). Due to the synergistic effect of ...MoS2 and NG, enhancement of electrocatalytic oxygen-reduction was realized.
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•MoS2/Nitrogen-doped graphene (NG) composites were obtained by physically mixing method.•MoS2 sheets deposited NG could be used as effective electrocatalyst for ORR.•Enhanced electrocatalytic activity is due to the synergistic effect of MoS2 and NG.•The ORR is a four-electron process based on Koutecky-Levich equation.
A simple yet effective strategy was developed to generate a non-precious oxygen electrode electrocatalyst of MoS2/nitrogen-doped graphene (NG) by physical mixing MoS2 sheets with NG. The micrometer-sized MoS2 sheets were obtained through ultrasonication exfoliation of the bulk MoS2, only showing little oxygen reduction reaction (ORR) activity. MoS2/NG hybrid was obtained by loading MoS2 sheets onto NG through ultrasonication, and the resulting nanocomposites exhibited improved electrocatalytic activity for ORR with dominant 4 electron pathway in alkaline solutions. The exposed active edges as well as the synergistic effect and reduced resistance connection jointly make the MoS2/NG composite a highly competitive ORR catalyst.
•In this paper, 2 × 2 symmetric games in which the game payoff matrix is represented by fuzzy numbers were studied.•We introduce the fuzzy dilemma strength to classify fuzzy games.•The fuzzy fixation ...probability of the strategy is calculated when the game payoff matrix is represented by the normal fuzzy numbers.•The proposed fuzzy Moran model was applied to solve the problem of strategy selection in the interaction between pollution-producing enterprises.
Most of the previous studies on the evolutionary dynamics of the Moran process assumed that the payoff obtained by the participant from the games is deterministic and expressed in precise numbers. However, because of the influence of various uncertain factors of the environment, the individual's payoff is not an accurate number but needs to be expressed by a fuzzy number. In this paper, 2 × 2 symmetric games in which the game payoff matrix is represented by fuzzy numbers were studied. Firstly, we introduce the fuzzy dilemma strength to classify fuzzy games. Then, the evolution dynamics of a fuzzy Moran process of a finite population are analyzed by using the operation of a fuzzy number. Under the condition of weak selection, the fuzzy fixation probability of the strategy is calculated when the game payoff matrix is represented by the normal fuzzy numbers. Furthermore, the conditions under which natural selection favors one strategy to be fixed in population and a strategy to become a fuzzy evolutionary stability strategy are analyzed. Lastly, the proposed fuzzy Moran model was applied to solve the problem of strategy selection in the interaction between pollution-producing enterprises. By numerical analysis, the effect of fuzzy dilemma strength on the fuzzy fixation probability was illustrated and then the feasibility and effectiveness of the method were verified. The extension of classical game dynamics to a fuzzy environment enriches the theory of evolutionary games and is more realistic.
In this paper, for balanced quaternary sequence pairs (BQSPs for short) of period
N
≡
1
(
mod
4
)
, the optimal cross-correlation is determined and a lower bound on the maximum autocorrelation ...magnitude is derived. Based on cyclotomic classes of order 4, we obtain two classes of nearly optimal BQSPs of period
N
, where
N
≡
5
(
mod
8
)
is a prime. Those pairs have optimal cross-correlation
{
1
,
-
1
}
and maximum out-of-phase autocorrelation magnitude no more than
N
-
4
+
4
, whose difference with a lower bound of maximum autocorrelation magnitude is less than 4.
Peanut is one of the most important oil crop species worldwide. NAC transcription factor (TF) genes play important roles in the salt and drought stress responses of plants by activating or repressing ...target gene expression. However, little is known about NAC genes in peanut.
We performed a genome-wide characterization of NAC genes from the diploid wild peanut species Arachis duranensis and Arachis ipaensis, which included analyses of chromosomal locations, gene structures, conserved motifs, expression patterns, and cis-acting elements within their promoter regions. In total, 81 and 79 NAC genes were identified from A. duranensis and A. ipaensis genomes. Phylogenetic analysis of peanut NACs along with their Arabidopsis and rice counterparts categorized these proteins into 18 distinct subgroups. Fifty-one orthologous gene pairs were identified, and 46 orthologues were found to be highly syntenic on the chromosomes of both A. duranensis and A. ipaensis. Comparative RNA sequencing (RNA-seq)-based analysis revealed that the expression of 43 NAC genes was up- or downregulated under salt stress and under drought stress. Among these genes, the expression of 17 genes in cultivated peanut (Arachis hypogaea) was up- or downregulated under both stresses. Moreover, quantitative reverse transcription PCR (RT-qPCR)-based analysis revealed that the expression of most of the randomly selected NAC genes tended to be consistent with the comparative RNA-seq results.
Our results facilitated the functional characterization of peanut NAC genes, and the genes involved in salt and drought stress responses identified in this study could be potential genes for peanut improvement.
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•Rare earth metal oxide/graphene electrocatalyst with ORR activity was reported.•Electrocatalyst was synthesized by thermal treatment of Ce3+-doped GO.•Crystallization of CeO2 can be ...controlled through thermal treatment temperature.•CeO2/rGO nanocomposites obtained at 750°C exhibits superior ORR activity.•Synergistic effect of CeO2 and rGO makes catalyst high performance.
In this paper, a facile and simple strategy was developed for in-situ growth cerium oxide nanoparticles on reduced graphene oxide (rGO) through thermal treatment of the Ce3+-doped graphene oxide(GO) under nitrogen atmosphere. Through regulation the thermal treatment temperature, the growth of cerium oxide nanocrystals can be easily controlled in accompany with the reduction of GO. The morphology and chemical composition of the as-synthesized CeO2/rGO at different temperature are characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. The nanocomposites show electrocatalytic activity toward the oxygen reduction reaction (ORR) in alkaline solution. Especially, the cerium oxide nanoparticles/rGO nanocomposites treated at 750°C possess excellent electrocatalytic ability with a dominating four-electron pathway, high tolerance of methanol and long-term operation stability due to the well exfoliation of graphene and perfect crystalline structure of cerium oxide. Compared to the commercial Pt/C catalyst, the synergistic effect of the fast electron transport of rGO and the high electrocatalytic activity of cerium oxide nanocrystals makes the nanocomposites as advanced, non-precious electrocatalysts for ORR.
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