Shanghai Jiao Tong University

About: Shanghai Jiao Tong University is a education organization based out in Shanghai, Shanghai, China. It is known for research contribution in the topics: Population & Cancer. The organization has 157524 authors who have published 184620 publications receiving 3451038 citations. The organization is also known as: Shanghai Communications University & Shanghai Jiaotong University.

Arbitrage asymmetry and the idiosyncratic volatility puzzle

Abstract: Short selling, as compared to purchasing, faces greater risks and other potential impediments. This arbitrage asymmetry explains the negative relation between idiosyncratic volatility (IVOL) and average return. The IVOL effect is negative among overpriced stocks but positive among underpriced stocks, with mispricing determined by combining 11 return anomalies. The negative effect is stronger, consistent with asymmetry in risks and other impediments inhibiting arbitrageurs in exploiting mispricing. Aggregating across all stocks therefore yields a negative relation, explaining the IVOL puzzle. Further supporting our explanation is a negative relation over time between the IVOL effect and investor sentiment, especially among overpriced stocks.

Trading performance, disposition effect, overconfidence, representativeness bias, and experience of emerging market investors

Abstract: Using brokerage account data from China, we study investment decision making in an emerging market. We find that Chinese investors make poor trading decisions: the stocks they purchase underperform those they sell. We also find that Chinese investors suffer from three behavioral biases: (i) they tend to sell stocks that have appreciated in price, but not those that have depreciated in price, consistent with a disposition effect, acknowledging gains but not losses; (ii) they seem overconfident; and (iii) they appear to believe that past returns are indicative of future returns (a representativeness bias). In comparisons to prior findings, Chinese investors seem more overconfident than U.S. investors (i.e., the Chinese hold fewer stocks, yet trade very often) and their disposition effect appears stronger. Finally, we categorize Chinese investors based on proxy measures of experience and find that “experienced” investors are not always less prone to behavioral biases than are “inexperienced” ones. Copyright © 2007 John Wiley & Sons, Ltd.

Multi-Task Feature Learning for Knowledge Graph Enhanced Recommendation

Abstract: Collaborative filtering often suffers from sparsity and cold start problems in real recommendation scenarios, therefore, researchers and engineers usually use side information to address the issues and improve the performance of recommender systems. In this paper, we consider knowledge graphs as the source of side information. We propose MKR, a Multi-task feature learning approach for Knowledge graph enhanced Recommendation. MKR is a deep end-to-end framework that utilizes knowledge graph embedding task to assist recommendation task. The two tasks are associated by crosscompress units, which automatically share latent features and learn high-order interactions between items in recommender systems and entities in the knowledge graph. We prove that crosscompress units have sufficient capability of polynomial approximation, and show that MKR is a generalized framework over several representative methods of recommender systems and multi-task learning. Through extensive experiments on real-world datasets, we demonstrate that MKR achieves substantial gains in movie, book, music, and news recommendation, over state-of-the-art baselines. MKR is also shown to be able to maintain satisfactory performance even if user-item interactions are sparse.

Mesenchymal stem cells: a double-edged sword in regulating immune responses

Abstract: Mesenchymal stem cells (MSCs) have been employed successfully to treat various immune disorders in animal models and clinical settings. Our previous studies have shown that MSCs can become highly immunosuppressive upon stimulation by inflammatory cytokines, an effect exerted through the concerted action of chemokines and nitric oxide (NO). Here, we show that MSCs can also enhance immune responses. This immune-promoting effect occurred when proinflammatory cytokines were inadequate to elicit sufficient NO production. When inducible nitric oxide synthase (iNOS) production was inhibited or genetically ablated, MSCs strongly enhance T-cell proliferation in vitro and the delayed-type hypersensitivity response in vivo. Furthermore, iNOS−/− MSCs significantly inhibited melanoma growth. It is likely that in the absence of NO, chemokines act to promote immune responses. Indeed, in CCR5−/−CXCR3−/− mice, the immune-promoting effect of iNOS−/− MSCs is greatly diminished. Thus, NO acts as a switch in MSC-mediated immunomodulation. More importantly, the dual effect on immune reactions was also observed in human MSCs, in which indoleamine 2,3-dioxygenase (IDO) acts as a switch. This study provides novel information about the pathophysiological roles of MSCs.