Optimal Bubble Riding: A Mean Field Game with Varying Entry Times

Recent financial bubbles such as the emergence of cryptocurrencies and "meme stocks" have gained increasing attention from both retail and institutional investors. In this paper, we propose a game-theoretic model on optimal liquidation in the presence of an asset bubble. Our setup allows the influx of players to fuel the price of the asset. Moreover, traders will enter the market at possibly different times and take advantage of the uptrend at the risk of an inevitable crash. In particular, we consider two types of crashes: an endogenous burst which results from excessive selling, and an exogenous burst which cannot be anticipated and is independent from the actions of the traders. The popularity of asset bubbles suggests a large-population setting, which naturally leads to a mean field game (MFG) formulation. We introduce a class of MFGs with varying entry times. In particular, an equilibrium will depend on the entry-weighted average of conditional optimal strategies. To incorporate the exogenous burst time, we adopt the method of progressive enlargement of filtrations. We prove existence of MFG equilibria using the weak formulation in a generalized setup, and we show that the equilibrium strategy can be decomposed into before-and-after-burst segments, each part containing only the market information. We also perform numerical simulations of the solution, which allow us to provide some intriguing results on the relationship between the bubble burst and equilibrium strategies.Comment: 54 pages, 3 figure

Optimal Bubble Riding with Price-dependent Entry: a Mean Field Game of Controls with Common Noise

In this paper we further extend the optimal bubble riding model proposed by Tangpi and Wang by allowing for price-dependent entry times. Agents are characterized by their individual entry threshold that represents their belief in the strength of the bubble. Conversely, the growth dynamics of the bubble is fueled by the influx of players. Price-dependent entry naturally leads to a mean field game of controls with common noise and random entry time, for which we provide an existence result. The equilibrium is obtained by first solving discretized versions of the game in the weak formulation and then examining the measurability property in the limit. In this paper, the common noise comes from two sources: the price of the asset which all agents trade, and also the exogenous bubble burst time, which we also discretize and incorporate into the model via progressive enlargement of filtration.Comment: 31 page

Long-Term Exposure to High Altitude Affects Voluntary Spatial Attention at Early and Late Processing Stages

The neurocognitive basis of the effect of long-term high altitude exposure on voluntary attention is unclear. Using event related potentials, the high altitude group (people born in low altitude but who had lived at high altitude for 3 years) and the low altitude group (living in low altitude only) were investigated using a voluntary spatial attention discrimination task under high and low perceptual load conditions. The high altitude group responded slower than the low altitude group, while bilateral N1 activity was found only in the high altitude group. The P3 amplitude was smaller in the high altitude compared to the low altitude group only under high perceptual load. These results suggest that long-term exposure to high altitudes causes hemispheric compensation during discrimination processes at early processing stages and reduces attentional resources at late processing stages. In addition, the effect of altitude during the late stage is affected by perceptual load

Testing and Micromechanical Modelling of Rockfill Materials Considering the Effect of Stress Path

We have extended the micromechanics-based analytical (M-A) model to make it capable of simulating Nuozhadu rockfill material (NRFM) under different stress paths. Two types of drained triaxial tests on NRFM were conducted, namely, the stress paths of constant stress ratio (CSR) and the complex stress paths with transitional features. The model was improved by considering the interparticle parameter variation with the unloading-reloading cycles and the effect of the stress transition path. The evolution of local dilatancy at interparticle planes due to an externally applied load is also discussed. Compared with Duncan-Chang’s E-u and E-B models, the improved model could not only better describe the deformation properties of NRFM under the stress path loading, but also present the volumetric strain changing from dilatancy to contractancy with increasing transitional confining pressures. All simulations have demonstrated that the proposed M-A model is capable of modelling the mechanical behaviour of NRFM in the dam

Government environmental information disclosure and corporate carbon performance

Environmental problem is the key to the healthy development of China’s eco-economy, and the environmental responsibility of micro-enterprises under the vision of “Dual Carbon” has attracted more attention. Under the effect of formal environmental regulation, firms will improve their environmental performance by improving technology and resource utilization. As an informal environmental system, can government environmental information disclosure (GEID) guide firms to actively carry out green innovation, ultimately improve the carbon emission problem of firms, have a positive impact on the carbon performance of enterprises, and provide strong support to protect ecological environment? To address this question, this study used the Pollution Information Transparency Index (PITI) to measure GEID, and empirically tested the impact of GEID on corporate carbon performance using a sample of listed companies involved in China’s mining and manufacturing industries from 2013 to 2018. The study found that the higher the degree of GEID, the better was the corporate carbon performance. However, the improved public participation weakened the effect of GEID on corporate carbon performance. GEID reduced the carbon emission intensity of firms and improved their carbon performance via green innovation. Further research indicated that the enhanced GEID in state-owned enterprises significantly improved carbon performance of firms. This study provides empirical evidence for GEID to improve corporate carbon performance, and also proposes a policy strategy for the government to guide firms to undertake green innovation and promote firms to improve efficient carbon use

NOTCH activation promotes glycosyltransferase expression in human myeloid leukemia cells

NOTCH signaling diversely regulates the growth of acute myeloid leukemia (AML) cells. It is known that glycosylation of NOTCH receptors modulates NOTCH activation. However, little is known about glycosylation of NOTCH in AML cells. We examined the effects of ligand-induced NOTCH activation on the expression of NOTCHmodifying glycosyltransferases in two AML cell lines, THP-1 and TMD7. The cells were stimulated with recombinant NOTCH ligands JAGGED1 and DELTA1, and subjected to immunoblot analysis to evaluate the expression levels of glycosyltransferases. Ligand stimulation promoted the expression of POFUT1, LFNG, MFNG, RFNG, GXYLT1, GXYLT2, and XXYLT1 in THP-1 cells, and that of RFNG and GXYLT1 in TMD7 cells. We found that NOTCH activation promoted the expression of several glycosyltransferases in AML cells. This suggests that NOTCH activation modulates its sensitivity to NOTCH ligands by increased glycosylation of NOTCH receptors in AML cells. Further investigation is needed to elucidate its biological significance

Optimal Analysis of Tunnel Construction Methods through Cross Passage from Subway Shaft

The conversion section of the cross passage and shaft is a priority concern in the stress transformation of a tunnel structure during subway underground excavation. In the construction of Subway Line 5 in Xi'an, China, the main line in the loess layer was constructed through the cross passage from the subway shaft of the Yue Deng Pavilion–San Dian Village Station tunnel section. Numerical simulation and field measurement were adopted to study the construction stability of the cross passage and shaft under two possible construction methods: the “shaft followed by cross passage construction” method and the “cross passage parallel shaft construction” method. The results showed that the surface deformation and plastic zone of the surrounding rock are similar under the two construction methods. However, of the two, the “cross passage parallel shaft construction” method was more advantageous in controlling the structural deformation of the original shaft and the stress distribution of the horsehead structure. The field monitoring data showed that the surface settlements and the deformation of the original shaft structures meet the requirement of control standards under the “cross passage parallel shaft construction” method