Freedom of choice adds value to public goods.

Public goods, ranging from judiciary to sanitation to parkland, permeate daily life. They have been a subject of intense interdisciplinary study, with a traditional focus being on participation levels in isolated public goods games (PGGs) as opposed to a more recent focus on participation in PGGs embedded into complex social networks. We merged the two perspectives by arranging voluntary participants into one of three network configurations, upon which volunteers played a number of iterated PGGs within their network neighborhood. The purpose was to test whether the topology of social networks or a freedom to express preferences for some local public goods over others affect participation. The results show that changes in social networks are of little consequence, yet volunteers significantly increase participation when they freely express preferences. Surprisingly, the increase in participation happens from the very beginning of the game experiment, before any information about how others play can be gathered. Such information does get used later in the game as volunteers seek to correlate contributions with higher returns, thus adding significant value to public goods overall. These results are ascribable to a small number of behavioral phenotypes, and suggest that societies may be better off with bottom-up schemes for public goods provision.

Tax thresholds yield multiple optimal cooperation levels in the spatial public goods game.

Income redistribution, which involves transferring income from certain individuals to others, plays a crucial role in human societies. Previous research has indicated that tax-based redistribution can promote cooperation by enhancing incentives for cooperators. In such a tax system, all individuals, irrespective of their income levels, contribute to the tax system, and the tax revenue is subsequently redistributed to everyone. In this study, we relax this assumption by introducing a tax threshold, signifying that only individuals with incomes exceeding the threshold will be subject to taxation. In particular, we employ the spatial public goods game to investigate the influence of tax rates-the percentage of income allocated to tax-and tax thresholds, which determine the income level at which individuals become taxable, on the evolution of cooperation. Our extensive numerical simulations disclose that tax thresholds produce complex outcomes for the evolution of cooperation, depending on tax rates. Notably, at low tax rates (i.e., below 0.41), as the tax threshold increases, discontinuous phase transitions in cooperation performance suggest the presence of multiple intervals of effective tax thresholds that promote peak cooperation levels. Nevertheless, irrespective of the chosen tax rate, once the tax threshold surpasses a critical threshold, the redistribution mechanism fails, causing the collapse of cooperation. Evolutionary snapshots show that self-organized redistribution forms an intermediary layer on the peripheries of cooperative clusters, effectively shielding cooperators from potential defectors. Quantitative analyses shed light on how self-organized redistribution narrows the income gap between cooperators and defectors through precise identification of tax-exempt entities, thereby amplifying the cooperative advantage. Collectively, these findings enhance our comprehension of how income redistribution influences cooperation, highlighting the pivotal role of tax thresholds.

FADS1-FADS2 and ELOVL2 gene polymorphisms in susceptibility to autism spectrum disorders in Chinese children.

BACKGROUD: Autism spectrum disorders (ASD) are a complex group of neurodevelopmental disorders with a genetic basis. The role of long-chain polyunsaturated fatty acids (LC-PUFAs) and the occurrence of autism has been the focus of many recent studies. The present study investigates whether genetic variants of the fatty acid desaturase (FADS) 1/2 and elongation of very long-chain fatty acids protein (ELOVL) 2 genes, which are involved in LC-PUFA metabolism, are associated with ASD risk. METHODS: A cohort of 243 ASD patients and 243 unrelated healthy controls were enrolled in this case control study. Sixteen tag single nucleotide polymorphisms from the FADS1-2 and ELOVL2 genes were genotyped using the Sequenom Mass Array. RESULTS: There were significant differences in allelic distribution of FADS2 rs526126 (OR = 0.55, 95% CI = 0.42-0.72, pFDR < 0.05) between autistic children and controls. FADS2 rs526126 and ELOVL2 rs10498676 were associated with decreased ASD risk in recessive model (OR = 0.07, 95% CI = 0.02-0.22, pFDR < 0.01; OR = 0.56, 95% CI = 0.35-0.89, pFDR = 0.042), while ELOVL2 rs17606561, rs3756963, and rs9468304 were associated with increased ASD risk in overdominant model (OR = 1.63, 95% CI = 1.12-2.36, pFDR = 0.036; OR = 1.64, 95% CI = 1.14-2.37, pFDR = 0.039; OR = 1.75, 95% CI = 1.22-2.50, pFDR = 0.017). The A/A genotype of rs10498676 was correlated with a decline in the Autism Diagnostic Interview-Revised communication (verbal and nonverbal) domain. CONCLUSIONS: These findings provide evidence of an association between FADS2 and ELOVL2 polymorphisms and ASD susceptibility in Chinese children.

Peer pressure induced punishment resolves social dilemma on interdependent networks.

Despite the fruitful evidence to support the emergence of cooperation, irrational decisions are still an essential part of promoting cooperation. Among the many factors that affect human rational decision-making, peer pressure is unique to social organisms and directly affects individual cooperative behaviors in the process of social interaction. This kind of pressure psychologically forces individuals to behave consistently with their partners, and partners with inconsistent behaviors may suffer psychological blows. As feedback, this psychological harm may in turn affect individual cooperative decisions. There is evidence that when peer pressure exists, partnerships can reduce free-riding in enterprise. Based on interdependent networks, this paper studies the impact of peer pressure on cooperation dynamics when the strategies of corresponding partners from different layers of the networks are inconsistent. We assume that when individuals are under peer pressure, their payoffs will be compromised. The simulation results show that the punishment effect will force the expulsion of partners with different strategies, which will further reduce the proportion of partners with inconsistent strategies in the system. However, in most cases, only moderate fines are most conductive to the evolution of cooperation, and the punishment mechanisms can effectively promote the interdependent network reciprocity. The results on the small world and random network prove the robustness of the result. In addition, under this mechanism, the greater the payoff dependence between partners, the better the effect of interdependent network reciprocity.

The effect of asymmetric reproductive ability on the evolution of cooperation on interdependent networks.

In this paper, we consider an asymmetric reproductive ability on interdependent networks and investigate how this setting affects the evolution of cooperation. In detail, players decide to update their strategies at each step on main network (network B), while for sub network (network A), players update their strategies with a fixed probability p. Obviously, the system restores the traditional case when p = 1, where cooperation can survive by interdependent network reciprocity. And our asymmetric set-up comes into play when p < 1. Numerical simulation results show that our asymmetric coupling will hinder the overall cooperation level for small p. In detail, the introduction of asymmetric reproductive ability urges the formation of symmetry breaking and further weakens the positive impact by location synchronous effect. And the root cause is entirely distinct situation of utility differences on two networks. These observations further demonstrate a class of phenomena on interdependent networks that it would have catastrophic consequences on one network even if a unrelated change only occurs seemingly on another network.

Association study between inwardly rectifying potassium channels 2.1 and 4.1 and autism spectrum disorders.

Autism spectrum disorders (ASD) are a group of neurodevelopmental disorders involving structural and functional impairment of the brain. Inwardly rectifying potassium (Kir) channels may contribute to the etiology of ASD by altering brain function. This study investigated the associations between genetic variants of KCNJ2 and KCNJ10 genes (encoding Kir2.1 and Kir4.1, respectively) and ASD risk in patients, and Kir channel expression in ASD model rats. This case-control study involved a cohort of 269 Chinese children with ASD and 243 unrelated healthy controls. Twelve tag single nucleotide polymorphisms (SNPs) from the KCNJ2 and KCNJ10 genes were genotyped by Sequenom Mass Array, while a valproic acid (VPA)-induced rat model of ASD was used to evaluate Kir channel expression in the hippocampus. Among the 12 examined SNPs, only KCNJ10 rs1186689 was significantly associated with disease susceptibility; the variant T allele conferred a lower risk of developing ASD [odds ratio (OR) = 0.61, 95% confidence interval (CI) = 0.47-0.80, p false discovery rate (FDR) = 0.012, and OR = 0.63, 95% CI = 0.48-0.84, pFDR = 0.014 at the allelic and genotypic levels, respectively]. Additionally, hippocampal Kir2.1 and Kir4.1 levels were decreased in VPA as compared to control rats. These results demonstrated that KCNJ10 (rs1186689) polymorphisms was correlated with ASD susceptibility in Chinese Han children, and the abnormal expression of Kir2.1 and Kir4.1 in ASD model rats suggested a mechanism by which Kir channels may play a role in ASD.

Factors influencing the severity of behavioral phenotype in autism spectrum disorders: Implications for research.

The phenotypic heterogeneity of Autism Spectrum Disorders (ASD) presents particular research challenges in the assessment of symptom severity, while the standardized Autism Diagnostic Observation Schedule (ADOS) scores present a severity metric, namely calibrated severity scores (CSS) that are relatively impervious to individual characteristics. To date, no studies have examined the convergent validity of CSS in Chinese sample populations. The present study investigated the validity of the ADOS-CSS using a sample of 321 children aged 2-18 years with ASD, and developed upon existing literature examining the influence of non-ASD-specific characteristics on other types of measures including Autism Diagnostic Interview-Revised (ADI-R), Social Responsiveness Scale (SRS), and Vineland Adaptive Behavior Scales (VABS). As expected, the findings revealed that the CSS were less influenced than ADOS-RAW scores by the demographic and developmental-level variables. Moreover, compared to the ADOS-CSS, the ADI-R, SRS and VABS were still strongly correlated with confounding factors, such as chronological age, intelligence quotients, and language-level. The results of this study corroborate the utilization of CSS as a more valid indicator of ASD severity than raw scores from ADOS and other instruments.