Heterogeneous indirect reciprocity promotes the evolution of cooperation in structured populations.

A fundamental aspect of all biological system is cooperation. Human society is based to a large extent on mechanisms that favor cooperation. Indirect reciprocity is a crucial factor for the emergence and maintenance of cooperation in evolutionary games. In this work, we introduce a mechanism of heterogeneous indirect reciprocity in the prisoner's dilemma game, where an altruistic attribute is considered. The so-called altruistic attribute refers to the trait that when an altruistic individual cooperates, its neighbors, regardless of their strategies, can gain additional benefits. Intuitively, altruistic cooperative agents seem to do only what is beneficial for others, but in fact, their neighbors tend to cooperate in order to maintain the cooperative strategies of altruistic individuals. In this way, the neighbors of cooperative altruistic individuals not only guarantee their own additional benefits, but also indirectly protect the income of altruistic individuals, which strengthens the links between cooperative individuals, thus promoting the evolution of cooperation. The robustness of the results is verified on homogeneous and heterogeneous networks. Moreover, the results of individual heterogeneity corroborate the existing evidence that heterogeneity, almost irrespective of its origin, promotes cooperative actions. Our conclusions might provide additional insights into understanding the roots of cooperation in social systems.

Pearson's goodness-of-fit tests for sparse distributions.

Pearson's chi-squared test is widely used to test the goodness of fit between categorical data and a given discrete distribution function. When the number of sets of the categorical data, say k, is a fixed integer, Pearson's chi-squared test statistic converges in distribution to a chi-squared distribution with k-1 degrees of freedom when the sample size n goes to infinity. In real applications, the number k often changes with n and may be even much larger than n. By using the martingale techniques, we prove that Pearson's chi-squared test statistic converges to the normal under quite general conditions. We also propose a new test statistic which is more powerful than chi-squared test statistic based on our simulation study. A real application to lottery data is provided to illustrate our methodology.

An antioxidant and antibacterial polydopamine-modified thermo-sensitive hydrogel dressing for Staphylococcus aureus-infected wound healing.

Bacteria-infected wound healing is a complex and chronic process that poses a great threat to human health. A thermo-sensitive hydrogel that undergoes a sol-gel transition at body temperature is an attractive wound dressing for healing acceleration and infection prevention. In this paper, we present a thermo-sensitive and reactive oxygen species (ROS)-scavenging hydrogel based on polydopamine modified poly(ε-caprolactone-co-glycolide)-b-poly(ethylene glycol)-b-poly(ε-caprolactone-co-glycolide) (PDA/P2) triblock copolymer. The PDA/P2 solution at a concentration of 30 wt% could form a gel at 34-38 °C. The ROS-scavenging ability of PDA/P2 was demonstrated by DPPH and ABTS assays and intracellular ROS downregulation in RAW264.7 cells. Furthermore, silver nanoparticles were encapsulated in the hydrogel (PDA/P2-4@Ag gel) to provide antibacterial activity against E. coli and S. aureus. An in vivo S. aureus-infected rat model demonstrated that the PDA/P2-4@Ag hydrogel dressing could promote wound healing via inhibiting bacterial growth, alleviating the inflammatory response, and inducing angiogenesis and collagen deposition. This study provides a new strategy to prepare temperature-sensitive hydrogel-based multifunctional wound dressings.

Temperature and pH Dual Responsive Nanogels of Modified Sodium Alginate and NIPAM for Berberine Loading and Release.

pH- and temperature-sensitive nanogels (NGs) were prepared from sodium alginate (SA) and N-isopropylacrylamide (NIPAM), as the sensitivity at pH 5.5 and 31 °C. SA was pH-modified with glutamic acid (Glu) and ethylenediamine (EDA). The products Glu-SA (Glu-modified SA) and EGSA (EDA- and Glu-modified SA) were characterized by ninhydrin color reaction, infrared spectroscopy, and zeta potential, and the best reactant ratio was selected. Moreover, temperature-sensitive, pH-sensitive EGSA-NGs possessing a semi-interpenetrating network structure were prepared by radical polymerization using N-isopropylacrylamide. The morphology of EGSA-NGs was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The cytotoxicity test shows the low cytotoxicity and high biocompatibility of the NGs. The newly prepared NGs were also subjected to pH-sensitive temperature-sensitive in vitro drug-loading and drug-release experiments. The pH-sensitive and temperature-sensitive experiments showed that the particle size of EGSA-NGs was reduced at pH 5.5 and above 31 °C. The drug-loading and drug-release experiments also confirmed this finding, indicating that the newly synthesized NGs could release the drug according to the environmental changes. Therefore, the material has potential application value in solid tumor targeted therapy.

A method for estimating the power of moments.

Let X be an observable random variable with unknown distribution function [Formula: see text], [Formula: see text], and let [Formula: see text] We call θ the power of moments of the random variable X. Let [Formula: see text] be a random sample of size n drawn from [Formula: see text]. In this paper we propose the following simple point estimator of θ and investigate its asymptotic properties: [Formula: see text] where [Formula: see text], [Formula: see text]. In particular, we show that [Formula: see text] This means that, under very reasonable conditions on [Formula: see text], [Formula: see text] is actually a consistent estimator of θ.

Prediction of daily PM2.5 concentration in China using partial differential equations.

Accurate reporting and forecasting of PM2.5 concentration are important for improving public health. In this paper, we propose a partial differential equation (PDE) model, specially, a linear diffusive equation, to describe the spatial-temporal characteristics of PM2.5 in order to make short-term prediction. We analyze the temporal and spatial patterns of a real dataset from China's National Environmental Monitoring and validate the PDE-based model in terms of predicting the PM2.5 concentration of the next day by the former days' history data. Our experiment results show that the PDE model is able to characterize and predict the process of PM2.5 transport. For example, for 300 continuous days of 2016, the average prediction accuracy of the PDE model over all city-regions is 93% or 83% based on different accuracy definitions. To our knowledge, this is the first attempt to use PDE-based model to study PM2.5 prediction in both temporal and spatial dimensions.

Investment preference promotes cooperation in spatial public goods game.

It is usually assumed that each cooperator contributes equally to different public pools in spatial public goods game. However, it is more reasonable to invest differently according to individual investment preference. In this paper, an extended public goods game, in which cooperators contribute to the groups according to the investment preference, is developed. The investment preference of a cooperator is characterized by the fraction of the cooperator from his/her own memory about a group and the intensity of investment preference is represented by a tunable parameter α. The well-mixed population and the structured population are analyzed under this mechanism. It is shown that the investment preference can give rise to coordination. Moreover, the extensive numerical simulation results show that with the increasing of investment preference density or memory length, the proportion of cooperation can increase monotonously. This is because the investment preference could help cooperators resist the invasion from defectors. Compared with the basic version, the new mechanism is able to promote cooperation effectively. Our research may provide a valuable insight for further exploring the nature of cooperation in the real world.

Higher-order Network Analysis of Fine Particulate Matter (PM 2.5) Transport in China at City Level.

Specification of PM 2.5 transmission characteristics is important for pollution control and policymaking. We apply higher-order organization of complex networks to identify major potential PM 2.5 contributors and PM 2.5 transport pathways of a network of 189 cities in China. The network we create in this paper consists of major cities in China and contains information on meteorological conditions of wind speed and wind direction, data on geographic distance, mountains, and PM 2.5 concentrations. We aim to reveal PM 2.5 mobility between cities in China. Two major conclusions are revealed through motif analysis of complex networks. First, major potential PM 2.5 pollution contributors are identified for each cluster by one motif, which reflects movements from source to target. Second, transport pathways of PM 2.5 are revealed by another motif, which reflects transmission routes. To our knowledge, this is the first work to apply higher-order network analysis to study PM 2.5 transport.

Impact of Social Reward on the Evolution of the Cooperation Behavior in Complex Networks.

Social reward, as a significant mechanism explaining the evolution of cooperation, has attracted great attention both theoretically and experimentally. In this paper, we study the evolution of cooperation by proposing a reward model in network population, where a third strategy, reward, as an independent yet particular type of cooperation is introduced in 2-person evolutionary games. Specifically, a new kind of role corresponding to reward strategy, reward agents, is defined, which is aimed at increasing the income of cooperators by applying to them a social reward. Results from numerical simulations show that consideration of social reward greatly promotes the evolution of cooperation, which is confirmed for different network topologies and two evolutionary games. Moreover, we explore the microscopic mechanisms for the promotion of cooperation in the three-strategy model. As expected, the reward agents play a vital role in the formation of cooperative clusters, thus resisting the aggression of defectors. Our research might provide valuable insights into further exploring the nature of cooperation in the real world.

Clinical predictors of outcomes in patients undergoing emergency air medical transport from Kinmen to Taiwan.

Emergency air medical transport (EAMT) is indispensable for acutely or critically ill patients in remote areas. We determined patient-level and transport-specific factors associated with all-cause mortality after EAMT.We conducted a population-based, retrospective cohort study using a prospective registry consisting of clinical/medical records. Study inclusion criteria consisted of all adults undergoing EAMT from Kinmen hospital to the ED of Taipei Veterans General Hospital (TVGH) between January 1, 2006 and December 31, 2012. The primary outcome assessments were 7-day and 30-day mortality.A total of 370 patients transported to TVGH were enrolled in the study with a mean age of 54.5 ±â€Š21.5 (SD) years and with a male predominance (71.6%). The average in-transit time was 1.4 ±â€Š0.4 hours. The 7-day, 30-day, and in-hospital mortality rates were 10.3%, 14.1%, and 14.9%. Among them 33.5% (124/370) were categorized under neurological etiologies, whereas 24.9% (90/370) cardiovascular, followed by 16.2% (60/370) trauma patients. Independent predictors associated with 7-day all-cause mortality were age (odds ratio [OR] 1.043, 95% confidence interval [CI] 1.016-1.070), Glasgow Coma Scale (GCS) (OR 0.730, 95% CI 0.650-0.821), and hematocrit level (OR 0.930, 95% CI 0.878-0.985). Independent predictors associated with 30-day all-cause mortality were age (OR 1.028, 95% CI 1.007-1.049), GCS (OR 0.686, 95% CI 0.600-0.785), hematocrit (OR 0.940, 95% CI 0.895-0.988), hemodynamic instability (OR 5.088 95% CI 1.769-14.635), and endotracheal intubation (OR 0.131 95% CI 0.030-0.569). The 7-day and 30-day mortality were not significantly related to transport-specific factors, such as length of flight, type of paramedic crew on board, or day and season of transport. Clinical patient-level factors, as opposed to transport-level factors, were associated with 7- and 30-day all-cause mortality in patients undergoing interfacility EAMT from Kinmen to Taiwan.

Infectious pathogens in pediatric patients with primary immunodeficiencies.

BACKGROUND AND PURPOSE: Primary immunodeficiency diseases (PIDs) are rare disorders. Unusual infections often guide the initial investigation for immunodeficiency. METHODS: In order to ascertain the organisms that lead to a predisposition for PIDs, we reviewed the charts of 92 children diagnosed with PIDs at the National Taiwan University Hospital between March 1984 and March 2004. RESULTS: Pneumonia was diagnosed in 92%, 81%, and 76.5% of patients with antibody, combined, and cellular deficiencies, respectively. Other major illnesses were similar in the 3 groups and included bronchiolitis, acute gastroenteritis, otitis media, and bacteremia. Skin abscess, pneumonia, and lymphadenitis (54.5%, 45%, and 27% of cases, respectively) were the most common infections in patients with phagocyte defects. Organisms were speciated in only 44.8% of infection episodes. Most viral infections were diagnosed by traditional and time-consuming viral culture. Prophylactic antibiotics were prescribed to 9 out of the 92 patients with PIDs. CONCLUSIONS: Early recognition of PIDs requires that practitioners be aware of the infection characteristics, and subsequent reliable and rapid molecular diagnosis are needed in such immunocompromised patients.

Modelling and computation in the valuation of carbon derivatives with stochastic convenience yields.

The anthropogenic greenhouse gas (GHG) emission has risen dramatically during the last few decades, which mainstream researchers believe to be the main cause of climate change, especially the global warming. The mechanism of market-based carbon emission trading is regarded as a policy instrument to deal with global climate change. Although several empirical researches about the carbon allowance and its derivatives price have been made, theoretical results seem to be sparse. In this paper, we theoretically develop a mathematical model to price the CO2 emission allowance derivatives with stochastic convenience yields by the principle of absence of arbitrage opportunities. In the case of American options, we formulate the pricing problem to a linear parabolic variational inequality (VI) in two spatial dimensions and develop a power penalty method to solve it. Then, a fitted finite volume method is designed to solve the nonlinear partial differential equation (PDE) resulting from the power penalty method and governing the futures, European and American option valuation. Moreover, some numerical results are performed to illustrate the efficiency and usefulness of this method. We find that the stochastic convenience yield does effect the valuation of carbon emission derivatives. In addition, some sensitivity analyses are also made to examine the effects of some parameters on the valuation results.

Modeling and Computation of Transboundary Industrial Pollution with Emission Permits Trading by Stochastic Differential Game.

Transboundary industrial pollution requires international actions to control its formation and effects. In this paper, we present a stochastic differential game to model the transboundary industrial pollution problems with emission permits trading. More generally, the process of emission permits price is assumed to be stochastic and to follow a geometric Brownian motion (GBM). We make use of stochastic optimal control theory to derive the system of Hamilton-Jacobi-Bellman (HJB) equations satisfied by the value functions for the cooperative and the noncooperative games, respectively, and then propose a so-called fitted finite volume method to solve it. The efficiency and the usefulness of this method are illustrated by the numerical experiments. The two regions' cooperative and noncooperative optimal emission paths, which maximize the regions' discounted streams of the net revenues, together with the value functions, are obtained. Additionally, we can also obtain the threshold conditions for the two regions to decide whether they cooperate or not in different cases. The effects of parameters in the established model on the results have been also examined. All the results demonstrate that the stochastic emission permits prices can motivate the players to make more flexible strategic decisions in the games.

Factors Associated With Hyperphagic Behavior in Patients With Dementia Living at Home.

OBJECTIVE: To investigate the prevalence and patterns of and factors associated with hyperphagic behavior in Taiwanese patients with dementia living at home. METHODS: A cross-sectional and correlational design was used. A total of 104 patients with dementia and their primary caregivers were recruited from the geriatric, neurology, and memory clinics of a regional hospital, a medical center and two day-care centers in central Taiwan. The data related to hyperphagic behavior, functional abilities, medical conditions, body weight, and demographic characteristics of patients as well as the demographic characteristics of their primary caregivers were collected between January and May 2013. RESULTS: Based on a strict criterion (a median score of 3 for the hyperphagic subscale), the prevalence of hyperphagia in patients with dementia was 53.8%. Specific hyperphagic patterns exhibited included increased food intake (49% of patients with dementia), hoarding (8.7%), oral exploration (6.8%), and pica (3.9%). Years of education of the patient, the use of antipsychotics in patients, and the age of primary caregivers explained 16.3% of the variance in hyperphagic behavior subscale scores (F = 6.47, p < .001). CONCLUSIONS: For the early identification and treatment of hyperphagic behavior in patients with dementia in home care or in clinic services provided by health professionals, specific attention should be paid to the usual eating behaviors of patients with lower levels of education or who are taking antipsychotic medication or those who have a female primary caregiver.

Congenital adrenal hyperplasia with 11 beta-hydroxylase deficiency.

A rare form of congenital adrenal hyperplasia (CAH), 11 beta-hydroxylase deficiency, may be misdiagnosed as 21-hydroxylase deficiency, the most common form of CAH, because of similar clinical presentations at times and elevated level of 17-hydroxyprogesterone in both conditions. We report a case of 11 beta-hydroxylase deficiency that was originally misdiagnosed as 21-hydroxylase deficiency. Hypertension and hypokalemia complicated with seizures and arrhythmia developed in this 9-year-old girl after abrupt withdrawal of oral dexamethasone but maintenance of fludrocortisone. Suspicion of 11 beta-hydroxylase deficiency led to DNA mutation analysis, which revealed a novel point mutation (CTG 461 CCG) in the CYP11B1 gene converting leucine to proline. Her condition stabilized rapidly after withdrawal of fludrocortisone and administration of hydrocortisone. Regular measurement of blood pressure should be performed in all patients with CAH and test of serum 11-deoxycortisol or deoxycorticosterone level should be performed in those patients with elevated blood pressure to avoid misdiagnosis of 11 beta-hydroxylase deficiency.