No abstract

We examine the relation between insiders' investment horizon and the information content of their trades with respect to future stock returns. We conjecture that an insider's investment horizon establishes a benchmark for expected patterns of continued trading behavior and thus helps identify unexpected insider trades, which should be more informative in efficient markets. Consistent with this conjecture, the trades of short-horizon insiders are both more unexpected and more informed, on average, than those of long-horizon insiders. Short-horizon insiders and their firms also tend to display characteristics that are associated with a greater focus on short-termism.

This study shows that the recent trajectory of a firm's profits predicts future profitability and stock returns. The predictive information contained in the trend of profitability is not subsumed by the level of profitability, earnings momentum, or other well-known determinants of stock returns. The profit trend also predicts the earnings surprise one quarter later, and analyst forecast errors over the following 12 months, suggesting that sophisticated investors underreact to the information in the profit trend. On the other hand, we find no evidence of investor overreaction, and our results cannot be explained by well-known risk factors. JEL Classifications: G12; G14.

Poly­(lactic acid) (PLA), one of the most promising biodegradable polymer products, has achieved wide applications for its relatively good mechanical properties and moderate degradability. Here we report an environment-friendly filler, the organic–inorganic composite Janus nanosheets (PLA/PBS JNs), which can jam at the interface of the PLA/PBS blend with a low threshold as the compatibilizer and can simultaneously toughen the composites and improve the gas barrier performance due to better interfacial interaction and tortuous path effect. With 0.3 wt % of PLA/PBS JNs added, the tensile strength and elongation at break of the PLA/PBS blend can be improved by 37% and 224%, respectively. After a further hot-pressing process, the barrier performance of the PLA/PBS composite membranes can be significantly enhanced since PLA, PLA/PBS JNs, and PBS are arranged in a nearly lamellar structure with oxygen permeability of 0.63 × 10–15 cm3 cm·cm–2 s–1 Pa–1 with only 0.5 wt % of PLA/PBS JNs.

This paper presents initial work with the application of basalt fiber (BF) in the field of reinforced cement composites. Effect of BF on mortar drying shrinkage, mechanical prosperities and bond performance were studied. The results showed that adding of BF reduced markedly dry shrinkage of mortar especially at early ages. BF mortar had a greater compressive and flexural strength at early hydration period，but had a little less strength at the age of 28-days than mortar without fiber. Four point bending tests shows that addition of BF increased effectively toughness of mortar specimen at 28-days at the same loading, but had not a remarkable effect on fracture strength. A good bond was observed between BF and mortar matrix interface zone by SEM in early ages and there was debonding phenomenon between BF and mortar matrix in the long-term ages.