Search

Efficient extraction of oxygen from ambient waters played a critical role in the development of early arthropods. Maximizing gill surface area enhanced oxygen uptake ability but, with gills necessarily exposed to the external environment, also presented the issue of gill contamination. Here we document setae inserted on the dorsal surface of walking legs of the benthic-dwelling middle Cambrian Olenoides serratus and on the gill shaft of the Late Ordovician Triarthrus eatoni. Based on their physical positions relative to gill filaments, we interpret these setae to have been used to groom the gills, removing particles trapped among the filaments. The coordination between setae and gill filaments is comparable to that seen among modern crustaceans, which use a diverse set of setae-bearing appendages to penetrate between gill filaments when grooming. Grooming is known relatively early in trilobite evolutionary history and would have enhanced gill efficiency by maximizing the surface area for oxygen uptake.

When combustion instability occurs, the pressure oscillation will result in periodic change, not only in the injector flow rate but also in the atomization characteristics of the injector. In this work, atomization characteristics of swirl injectors under a standing-wave acoustic field were studied experimentally; the effects of acoustic pressure and injector position were analyzed on atomization and injectors characteristics in the critical state. It was found that under the same acoustic pressure, the effect of the acoustic field at the velocity antinode was stronger than the effect at the acoustic intensity antinode; and there was little effect at the acoustic pressure antinode. The hysteresis phenomenon of the spray field was also found in low flow rate cases in the acoustic field. The effects of the flow rate and liquid viscosity on atomization characteristics were analyzed, and the behavior of the Faraday wave was observed and studied during the experiment.

Our results demonstrate that caffeine stimulates the EGFR-ERK1/2 pathway to increase the LDLR expression and ameliorate nonalcoholic fatty liver disease (NAFLD) in HFD-fed ApoE KO mice.

A palladium-catalyzed dearomatizing [2+2+1] spiroannulation of indoles with two molecular internal alkynes is developed in the presence of Cu(OAc)

Background: Intracerebral translocator protein 18 kDa (TSPO) mediates the transport of cholesterol from cytoplasm to mitochondria and activation of microglia. The change of TSPO and the dysfunction of microglia are closely related to the pathogenesis of Alzheimer’s disease (AD). Aims: This study aimed to investigate the effects of microglial TSPO and its selective ligand YL-IPA08 on the cognitive function of transgenic mice in 5 × familial Alzheimer’s disease (FAD) mouse model of AD. Methods: The TSPO knockout 5 × FAD transgenic mice were bred, and tested by Morris water maze. The effects of YL-IPA08 on cognitive abilities and expression of Aβ in 5 × FAD mice were also explored into. Results: The latency of escape by TSPO knockout 5 × FAD mice was significantly prolonged compared with the 5 × FAD group, indicating that the cognitive impairment of mice aggravated. With the attenuated phagocytic ability of microglia, the deposition of Aβ in prefrontal cortex of TSPO knockout 5 × FAD mice increased, and the expression of proinflammatory factors (IL-1β, TNF-α, IL-6) were upregulated. In addition, YL-IPA08 significantly reduced the latency of escape by 5 × FAD mice, increased the number of times of crossing over the platform by mice, and inhibited the deposition of Aβ in the prefrontal cortex of 5 × FAD mice without affecting the cleavage of APP. Conclusion: Our findings suggested that TSPO knockout in 5 × FAD mice inhibited microglial phagocytosis, promoted Aβ deposition and neuroinflammation, and aggravated cognitive dysfunction in AD mice. YL-IPA08 had a significant cognition-enhancing effect in 5 × FAD transgenic mice, which might provide a new basis for potential drug candidates in AD treatment.

I have put together 10 topics and labeled them as hypotheses, which outline my preferred practices. The topics relate to questionable nerve compression, double crush syndrome of nerves, motion therapy after surgery, delayed primary tendon repair, proximal pole fracture of the scaphoid, short splint, and indications for postoperative hand elevation. I found no proof whether my preferred methods are better than or inferior to alternative methods that others use. The 10 hypotheses are presented to stimulate thinking, clinical observation, or investigations and highlight several areas of research. Investigation into these hypotheses may avoid unnecessary treatment or improve postsurgical comfort for patients and long-term outcomes of treatment.

Due to waning immunity and protection against infection with SARS-CoV-2, a third dose of a homologous or heterologous COVID-19 vaccine has been proposed by health agencies for individuals who were previously primed with two doses of an inactivated COVID-19 vaccine.We did a randomised, open-label, controlled trial to evaluate the safety and immunogenicity of heterologous boost immunisation with an orally administered aerosolised adenovirus type-5 vector-based COVID-19 vaccine (Ad5-nCoV) in Chinese adults (≥18 years old) who had previously received two doses of an inactivated SARS-CoV-2 vaccine-Sinovac CoronaVac. Eligible participants were randomly assigned (1:1:1) to receive a heterologous booster vaccination with a low dose (1·0 × 10Between Sept 14 and 16, 2021, 420 participants were enrolled: 140 (33%) participants per group. Adverse reactions were reported by 26 (19%) participants in the low dose group and 33 (24%) in the high dose group within 14 days after the booster vaccination, significantly less than the 54 (39%) participants in the CoronaVac group (p0·0001). The low dose group had a serum NAb GMT of 744·4 (95% CI 520·1-1065·6) and the high dose group had a GMT of 714·1 (479·4-1063·7) 14 days after booster dose, significantly higher than the GMT in the CoronaVac group (78·5 [60·5-101·7]; p0·0001).We found that a heterologous booster vaccine with an orally administered aerosolised Ad5-nCoV is safe and highly immunogenic in adults who have previously received two doses of CoronaVac as the primary series vaccination.National Natural Science Foundation of China and Jiangsu Provincial Key Research and Development Program.

This article discusses ulnar, median, and radial nerve compression in the proximal forearm and elbow and some possible common misconceptions. In particular, the ligament of Struthers extremely rarely causes ulnar neuropathy. Lacertus syndrome and flexor superficialis-pronator syndrome can be diagnosed separately. Surgical release can be through a small incision. Acronyms for compression to radial nerve in proximal forearm can be simplified to radial tunnel syndrome, which includes a mild type (classical radial tunnel syndrome) and a severe type (posterior interosseous nerve (PIN) compression).

To date, there has been little research considering both autism spectrum disorder (ASD) symptom severity and motor impairment simultaneously when investigating their associations with obesity. This study was designed to identify the moderating role of symptom severity in the relationship between motor competence and overweight/obesity for children with ASD. Seventy-eight children with a clinical diagnosis were recruited from a large autism rehabilitation center in Wuhan, China. Chi-square, partial correlation, and moderation regression analyses revealed that the prevalence of overweight and obesity was similar regardless of symptom severity. Balance was the only motor skill that correlated with body mass index. Furthermore, symptom severity significantly moderated the correlation. Children with low autism severity might be more likely to demonstrate the relationship between balance and body mass index than those with high autism severity. Combating obesity by enhancing motor competence should cautiously consider personal and environment factors such as individual severity of ASD.

Atherosclerosis (AS) is a chronic progressive disease caused by various factors, and causes various cerebrovascular and cardiovascular diseases (CVDs). Reducing the plasma levels of low-density lipoprotein-cholesterol (LDL-C) is the primary goal in preventing and treating AS. Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) plays a crucial role in regulating LDL-C metabolism. Panax notoginseng has potent lipid-reducing effects and protects against CVDs, and its saponins induce vascular dilatation, inhibit thrombus formation, and are used in treating CVDs. However, the anti-AS effect of the secondary metabolite, 20(S) -protopanaxatriol (20(S)-PPT), remains unclear. In this study, the anti-AS effect and molecular mechanism of 20(S)-PPT were investigated in vivo and in vitro by western blotting, real time-polymerase chain reaction (RT-PCR), Enzyme-linked Immunosorbent Assay (ELISA), immunofluorescence staining, and other assays. The in vitro experiments revealed that 20(S)-PPT reduced the levels of PCSK9 in the supernatant of HepG2 cells, upregulated low density lipoprotein receptor (LDLR) protein levels, promoted LDL uptake by HepG2 cells, and reduced PCSK9 mRNA transcription by upregulating the levels of FoxO3 protein and mRNA and decreasing the levels of HNF1α protein and mRNA. The in vivo experiments revealed that 20(S)-PPT upregulated aortic αSMA expression, increased the stability of atherosclerotic plaques, and reduced aortic plaque formation induced by a high-cholesterol fed in ApoE-/- mice (HCF group). Additionally, 20(S)-PPT reduced the aortic expression of CD68, reduced inflammation in the aortic root, and alleviated the hepatic lesions in the HCF group. The study revealed that 20(S)-PPT inhibited LDLR degradation via PCSK9 to alleviate AS.

BackgroundDuchenne muscular dystrophy (DMD) patients exhibit a late left ventricular systolic dysfunction preceded by an occult phase, during which myocardial fibrosis progresses and some early functional impairments can be detected. These latter include electrocardiographic (ECG) and heart rate variability (HRV) abnormalities.MethodsA longitudinal study aiming at describing the sequence of ECG and HRV abnormalities, relative to cardiac function degradation, using Holter ECG, was performed in the GRMD (Golden retriever muscular dystrophy) dog model, known to develop a DMD-like disease, including cardiomyopathy.ResultsMost of the known ECG and HRV abnormalities described in DMD patients were also found in GRMD dogs, and several of them could be detected months before the decrease of fractional shortening. One of the earliest evidenced abnormalities was a decrease in the very low frequency (VLF) component of the power spectrum, and this decrease was correlated with the further reduction of fractional shortening. Such decreased VLF probably reflects impaired autonomic function and abnormal vasomotor tone.ConclusionThis study provides new insights into the knowledge of the GRMD dog model and DMD cardiomyopathy and emphasizes the interest to monitor the VLF power in DMD patients, still unexplored in this disease, whilst it is highly predictive of deleterious clinical events in many other pathological conditions.AbbreviationscTpnICardiac Troponin IDMDDuchenne Muscular DystrophyECGElectrocardiogramGRMDGolden Retriever Muscular DystrophyHFHigh FrequencyHRHeart RateHRVHeart Rate VariabilityLFLow FrequencyLGELate Gadolinium EnhancementLTVLong-Term VariabilityLVEFLeft Ventricular Ejection FractionNT-proBNPN-Terminal part of the pro-Brain Natriuretic PeptidepNN50percentage of interval differences of successive RR intervals of more than 50 mspNN10 %(meanRR)percentage of interval differences of successive RR intervals of more than 10% of the mean RRQTccorrected QT intervalRMSSDsquare root of the mean squared differences of successive RR intervalsSDNNStandard Deviation of the RR intervalsLVFSLeft Ventricular Fractional ShorteningSTVShort-Term VariabilityVLFVery Low FrequencyPVBPremature Ventricular BeatVTVentricular Tachycardia.

ObjectiveThis study aimed to prospectively observe the efficacy and safety of CalliSpheres drug-eluting beads bronchial arterial chemoembolization (DEB-BACE) for refractory non-small-cell lung cancer (NSCLC).MethodsThe interventional therapy plan was as follows: 300–500 μm CalliSpheres drug-loaded microspheres were loaded with epirubicin, and then slow embolization of tumor supplying artery was performed after microcatheter superselection. Chest enhanced computed tomography and related hematological examination were reviewed after 2 months of DEB-BACE, and the tumor response after the first interventional therapy was evaluated using modified response evaluation criteria in solid tumors. The overall survival (OS) of patients was determined, and the quality of life and the incidence rate of adverse reactions were observed.ResultsFrom January 2019 to January 2021, 43 patients with refractory NSCLC were enrolled. The patients were followed up until June 2022. All 43 patients underwent DEB-BACE 1.79 ± 0.69 times on average. The 3-, 6-, 12-, and 24-month survival rates were 100%, 86.0%, 41.9%, and 11.8%, respectively. The median OS was 11.5 months. After the first interventional treatment, cough and wheezing significantly improved in 31 patients, hemoptysis was effectively controlled in 12 patients, and superior vena cava compression disappeared in 2 patients after 2 times of treatment. The general health status of the patients after treatment significantly improved compared with that before treatment, including the improvement in physical and emotional functions. Fatigue, nausea and vomiting, dyspnea, and insomnia improved significantly after treatment. No serious adverse events, such as spinal cord injury and cerebral embolism, were observed during the perioperative period. The main adverse reaction after DEB-BACE was chest pain (13/43, grade 1) followed by fever (10/43, grade 1–2), which was significantly relieved within 3–5 days after symptomatic treatment. Other adverse reactions included irritating cough, nausea and vomiting, and bone marrow suppression, and the incidence was less than 20%.ConclusionsDEB-BACE was effective and safe in treating refractory NSCLC, which could significantly improve patients’ quality of life and was worthy of clinical promotion and application.

Simple summarySomatic and germline aberrations in homologous recombinant repair (HHR) genes are associated with increased incidence and poor prognosis for prostate cancer. Through next-generation sequencing of prostate cancer patients across all clinical states from north China, here the authors identified a somatic mutational rate of 3% and a germline mutational rate of 3.9% for HRR genes using 200 tumor tissues and 714 blood specimens. Thus, mutational rates in HRR genes were lower compared with previous studies.BackgroundHomologous recombination repair deficiency is associated with higher risk and poorer prognosis for prostate cancer. However, the landscapes of somatic and germline mutations in these genes remain poorly defined in Chinese patients, especially for those with localized disease and those from north part of China. In this study, we explore the genomic profiles of these patients.MethodsWe performed next-generation sequencing with 200 tumor tissues and 714 blood samples from prostate cancer patients at Peking University First Hospital, using a 32 gene panel including 19 homologous recombination repair genes.ResultsTP53, PTEN, KRAS were the most common somatic aberrations; BRCA2, NBN, ATM were the most common germline aberrations. In terms of HRR genes, 3% (6/200) patients harbored somatic aberrations, and 3.8% (28/714) patients harbored germline aberrations. 98.0% (196/200) somatic-tested and 72.7% (519/714) germline tested patients underwent prostatectomy, of which 28.6% and 42.0% had Gleason scores ≥8 respectively. Gleason scores at either biopsy or prostatectomy were predictive for somatic aberrations in general and in TP53; while age of onset ConclusionsOur results showed a distinct genomic profile in homologous recombination repair genes for patients with prostate cancer across all clinical states from north China. Clinicians may consider to expand the prostate cancer patients receiving genetic tests to include more individuals due to the weak guiding role by the clinical factors currently available.

Soil moisture is an important parameter in numerical weather forecasting and climate projection studies, and it is extremely important for arid and semiarid areas. Different from those in relatively wet areas, for arid and semiarid areas, mechanisms associated with the transportation, condensation, and evaporation of water vapor in soil interior cannot be neglected. In this paper, schemes associated with soil evaporation and coupled transport of soil moisture and heat were developed for the integrated urban land model (IUM) to improve the simulation of soil moisture in arid and semiarid areas. The whole layer soil evaporation (WSE) scheme was developed to improve the simulation of soil evaporation. The soil’s inner layer water vapor transport is considered a part of WSE. The transport of water and heat in the inner soil was linked to the phase change of water. The NASA Soil Moisture Active Passive (SMAP) mission Level-4 Soil Moisture product and 10-cm volumetric soil moisture observations in 358 autonomic soil moisture observation sites were used for validating the simulation results. The results indicate that after using the WSE scheme and considering the coupled transport of moisture and heat in the soil interior, the simulation of soil moisture was improved definitely. For June, July, and August, the biases of soil moisture simulation decreased by approximately 22.5, 34.4, and 27.5%, respectively, while the RMSEs decrease by approximately 7.0, 8.7, and 9.6%, respectively. The improvement of soil moisture simulation indicates that in arid and semiarid areas soil water vapor transport is important and cannot be neglected.

Microbial nitrogen (N) immobilization, which typically results in soil N retention but based on the balance of gross N immobilization over gross N production, affects the fate of the anthropogenic reactive N. However, global patterns and drivers of soil gross immobilization of ammonium (I

Attempts to determine why some patients respond to electroconvulsive therapy (ECT) are valuable in schizophrenia. Schizophrenia is associated with aberrant dynamic functional architecture, which might impact the efficacy of ECT. We aimed to explore the relationship between pre-treatment temporal variability and ECT acute efficacy. Forty-eight patients with schizophrenia and 30 healthy controls underwent functional magnetic resonance imaging to examine whether patterns of temporary variability of functional architecture differ between high responders (HR) and low responders (LR) at baseline. Compared with LR, HR exhibited significantly abnormal temporal variability in right inferior front gyrus (IFGtriang.R), left temporal pole (TPOsup.L) and right middle temporal gyrus (MTG.R). In the pooled patient group, ∆PANSS was correlated with the temporal variability of these regions. Patients with schizophrenia with a distinct dynamic functional architecture appear to reveal differential response to ECT. Our findings provide not only an understanding of the neural functional architecture patterns that are found in schizophrenia but also the possibility of using these measures as moderators for ECT selection.

Purpose: With the belief that situational interest (SI) can be characterized as being triggered and maintained, the authors conducted this study to identify the underlying structure of SI and to develop a new measurement in physical education. Method: There were 558 students from two urban high schools in Shanghai, China, who served as participants. The authors developed the Situational Interest Inventory-Physical Education through three systematic stages. Both exploratory factor analysis and confirmatory factor analysis were conducted. Results: An exploratory factor analysis provided preliminary support, with a model comprising three components: triggered SI, maintained SI feeling, and maintained SI value. The three-component model was further corroborated through a confirmatory factor analysis. Its predictive validity was supported with significant correlations to in-class engagement. Conclusion: The findings lend initial evidence to the theoretical mechanism of interest development. Clarifying how SI is related to the mode of teachers’ instruction and learning content may help design effective motivational strategies and nurture long-term individual interest.

In an information age, people often need to face a lot of decision-making information when making decisions. Some indicators are on the high side and others are on the low side which is a common phenomenon in decision-making. So, it is difficult to make a correct and rational judgment. Long-term research has proved that information aggregation operator is an effective tool to solve this kind of problem. Bonferroni mean (BM) is an important information aggregation tool which has the main feature of capturing the interrelationships among aggregated arguments. Because the existing geometric Bonferroni mean (GBM) cannot reflect the two-layer average calculation and the weighted GBM do not feature reducibility, this paper develops the intuitionistic fuzzy normalized weighted optimized GBM (IFNWOGBM) and the generalized intuitionistic fuzzy normalized weighted optimized GBM (GIFNWOGBM) and also studies their desirable properties and special cases. In the end, based on the IFNWOGBM and GIFNWOGBM, a method to multiple attribute decision-making (MADM) problem is proposed. In order to verify the effectiveness of the method, it is used to select the location of the library.

Major water loss in the first stage of wood-derived carbon preparation had a direct impact on pore structure during the subsequent pyrolysis of biochar materials. To explore the changes in pore space at this stage, poplar was used as the subject of this study. The pore morphology before and after water evaporation was quantitatively characterized by scanning electron microscope, nitrogen adsorption method, and mercury injection method. Both the fractal dimensions of the multistage pores were obtained by the Frenkel-Halsey-Hill model and the thermodynamic relationship model. The results showed as follows: the adsorption isotherms were presented the mixed type of II and IV after supercritical drying, indicating the mesopores and macropores of wood. The adsorption isotherms after conventional drying were characterized a type II, which was inferred to the reduced mesopores compared to supercritical drying. The hysteresis loops of all wood samples were examined for the H3 type, which was deduced from the presence of slit-like pores. After treatment at 103±2 °C, the porosity and its connectivity properties are reduced by the mercury pressure data. For μm. Stability of the pore fractal dimension in the pore size >50 nm stage. This indicates that the conventional drying treatment made the micropore complexity increase, and leads to a reduced or invariable pore structure complexity for the >50 nm. The fractal analysis could assist in better analyzing the changes of pore structure and provide a new perspective for studying the pore structure in the carbonation stage.

The objectives of the study were to investigate changes in the mRNA expression levels of five genes during antral follicle development and to assess the efficacy of four timed-artificial insemination (TAI) protocols in female yaks (

Our results demonstrate that PPD directly binds to the extracellular domain of LDLR and inhibits the interaction between PCSK9 and LDLR, thereby increasing the levels of LDLR and alleviating atherosclerosis in HFD-fed ApoE KO mice.

All-scale scattering contributes to the reduction of lattice thermal conductivity of SiGe-based TE materials and leads to a maximum ZT value of 1.47 at 873 K, which is best one in the temperature range of 300–900 K ever reported.

The scarcity of two-dimensional (2D) magnetic nanostructures has hindered their applications in spintronics, which is attributed to that most magnetic materials exhibit non-van der Waals (nvdWs) structure and it is hard to reduce their thickness to 2D nanostructures. Thus it is eager to develop a promising strategy for free-standing 2D magnetic nvdWs nanostructures. We have achieved free-standing 2D nvdWs hexagonal FeSe with a thickness of 2.9 nm by the reaction between oleylamine-Se complex and Fe2+ with the assistance of Cl-, where the synergetic effects of Cl- and -NH2 lead to the anisotropic growth. Inspiringly, the 2D hexagonal FeSe exhibits intrinsic antiferromagnetic order rooted in Fe2+ and semiconductor nature. In addition, the temperature variation would result in the chemical environment changes of Fe2+, responsible for the temperature-dependent magnetic transitions. This work promotes the potential applications of 2D hexagonal FeSe and the preparation of other 2D nvdWs materials.

We report a copper-catalyzed ligand-controlled selective 1,2- and 1,4-hydrosilylation of 1,3-enynes, which furnishes enantiomerically enriched propargyl- and 1,2-allenylsilane products in high yields with excellent enantioselectivities (up to 99% ee). This reaction proceeds under mild conditions, shows broad substrate scope for both 1,3-enynes and trihydrosilanes, and displays excellent regioselectivities. Mechanistic studies based on deuterium-labeling reactions and density functional theory (DFT) calculations suggest that allenylcopper is the dominant reactive intermediate under both 1,2- and 1,4-hydrosilylation conditions, and it undergoes metathesis with silanes via selective four-membered or six-membered transition state, depending on the nature of the ligand. The weak interactions between the ligands and the reacting partners are found to be the key controlling factor for the observed regioselectivity switch.

The difficulty of appropriately assigning credit is particularly heightened in cooperative MARL with sparse reward, due to the concurrent time and structural scales involved. Automatic subgoal generation (ASG) has recently emerged as a viable MARL approach inspired by utilizing subgoals in intrinsically motivated reinforcement learning. However, end-to-end learning of complex task planning from sparse rewards without prior knowledge, undoubtedly requires massive training samples. Moreover, the diversity-promoting nature of existing ASG methods can lead to the "over-representation" of subgoals, generating numerous spurious subgoals of limited relevance to the actual task reward and thus decreasing the sample efficiency of the algorithm. To address this problem and inspired by the disentangled representation learning, we propose a novel "disentangled" decision-making method, Semantically Aligned task decomposition in MARL (SAMA), that prompts pretrained language models with chain-of-thought that can suggest potential goals, provide suitable goal decomposition and subgoal allocation as well as self-reflection-based replanning. Additionally, SAMA incorporates language-grounded RL to train each agent's subgoal-conditioned policy. SAMA demonstrates considerable advantages in sample efficiency compared to state-of-the-art ASG methods, as evidenced by its performance on two challenging sparse-reward tasks, Overcooked and MiniRTS., Comment: 39 pages, 10 figures

Long-term time-series forecasting (LTTF) has become a pressing demand in many applications, such as wind power supply planning. Transformer models have been adopted to deliver high prediction capacity because of the high computational self-attention mechanism. Though one could lower the complexity of Transformers by inducing the sparsity in point-wise self-attentions for LTTF, the limited information utilization prohibits the model from exploring the complex dependencies comprehensively. To this end, we propose an efficient Transformerbased model, named Conformer, which differentiates itself from existing methods for LTTF in three aspects: (i) an encoder-decoder architecture incorporating a linear complexity without sacrificing information utilization is proposed on top of sliding-window attention and Stationary and Instant Recurrent Network (SIRN); (ii) a module derived from the normalizing flow is devised to further improve the information utilization by inferring the outputs with the latent variables in SIRN directly; (iii) the inter-series correlation and temporal dynamics in time-series data are modeled explicitly to fuel the downstream self-attention mechanism. Extensive experiments on seven real-world datasets demonstrate that Conformer outperforms the state-of-the-art methods on LTTF and generates reliable prediction results with uncertainty quantification.

In multi-agent reinforcement learning, each agent acts to maximize its individual accumulated rewards. Nevertheless, individual accumulated rewards could not fully reflect how others perceive them, resulting in selfish behaviors that undermine global performance. The externality theory, defined as ``the activities of one economic actor affect the activities of another in ways that are not reflected in market transactions,'' is applicable to analyze the social dilemmas in MARL. One of its most profound non-market solutions, ``Pigovian Tax'', which internalizes externalities by taxing those who create negative externalities and subsidizing those who create positive externalities, could aid in developing a mechanism to resolve MARL's social dilemmas. The purpose of this paper is to apply externality theory to analyze social dilemmas in MARL. To internalize the externalities in MARL, the \textbf{L}earning \textbf{O}ptimal \textbf{P}igovian \textbf{T}ax method (LOPT), is proposed, where an additional agent is introduced to learn the tax/allowance allocation policy so as to approximate the optimal ``Pigovian Tax'' which accurately reflects the externalities for all agents. Furthermore, a reward shaping mechanism based on the approximated optimal ``Pigovian Tax'' is applied to reduce the social cost of each agent and tries to alleviate the social dilemmas. Compared with existing state-of-the-art methods, the proposed LOPT leads to higher collective social welfare in both the Escape Room and the Cleanup environments, which shows the superiority of our method in solving social dilemmas., Comment: 20 pages,13 figures

Additional file 3.