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The crash risks of momentum tend to be higher than those of size and value. International diversification lowers the crash risks of size and value but not momentum. The authors examined the conditional correlations and return co-exceedances of style portfolios across countries and found that this difference in the effect of diversification is due to the left (right) tails of momentum (size and value) portfolios being more correlated than the right (left) tails across countries.S tyle investing has grown in popularity among investors. Even at the retail level, as of 2008, there were more than 2,000 mutual funds and exchange-traded funds in the United States with a market-capitalization or value/growth focus. 1 According to statistics reported by Eun, Lai, de Roon, and Zhang (2010), such products are also becoming widely available in other developed countries. With respect to momentum, Jegadeesh and Titman (1993, p. 66) observed that "a majority of the mutual funds examined by Grinblatt and Titman (1989, 1993) show a tendency to buy stocks that have increased in price over the previous quarter."Many studies that have examined extreme events in the international equity market have focused on developing countries (see, e.g., Forbes and Rigobon 2002;Bae, Karolyi, and Stulz 2003;Bekaert, Harvey, and Ng 2005), but the recent financial crisis reminds us that even developed stock markets are not immune to crashes and tail risks. Taleb (2007) and Reinhart and Rogoff (2009), together with many others in the financial press, have also advised investors to pay more attention to these "rare" events.Motivated by the growth in popularity of style investing and the concerns about extreme events among investors, we examined the tail risks of style investing in the G-7 countries (Canada, France, Germany, Italy, Japan, United Kingdom, and United States) over 1981-2010. We evaluated whether portfolios with different size, value, or momentum tilts-the SMB (small minus big), HML (high minus low), and UMD (up minus down, or past winners minus past losers) portfolios-experience different crash risks and whether these risks can be mitigated through international diversification.■ Discussion of findings. Using both expected shortfall and return skewness as measures, we found that the left-tail risks of UMD are significantly higher than those of SMB and HML. 2 For diversified "world" portfolios (equal-weighted portfolios of the G-7 countries), this difference in left-tail risks across styles is even greater. By calculating conditional correlations (i.e., correlations conditional on returns of different magnitudes) and co-exceedances (i.e., joint occurrences of extreme returns) across countries, we found that the extreme negative returns on UMD in different markets tend to occur together, whereas those on SMB and HML tend to be country specific. In fact, for SMB and HML, the right-tail events tend to be more global in nature. These results suggest that momentum crashes cannot be diversified away internationally and explain why internatio...

The abalone, a marine mollusk, inhabits fast-flowing rocky reefs. Its predation and crawling abilities strongly depend on the adhesion capacity of its abdominal foot. Here, the macroscopic and microscopic morphology of the abalone foot was observed. The foot is divided into four main regions, each having a large number of folds on the surface. The extensional ability of the folds is the source of the abalone’s locomotory power. A high-speed camera was used to photograph the movement of an abalone. It was found that two to three deep-yellow round fold areas appear and disappear periodically on the surface of the foot. The folds move forward with the movement of the abalone. This results in a crawling motion that ensures efficiency of movement and adaptability of the wide abdominal foot to adsorptive surfaces. According to underwater tensile testing of an abalone, the adhesion force of the foot is composed of suction force, capillary force, friction and an interlocking structure. Among them, suction force is the most important component of the adhesion force, and the other factors play an auxiliary and reinforcing role. The strong adhesivity and adhesion-based crawling motion of the abalone may inspire new design ideas and mechanisms for underwater suckers.

The growth of certain methicillin-resistant Staphylococcus aureus (MRSA) isolates could be inhibited by NaCl higher than 2.5%. The objective of this study was to develop an enrichment method to recover NaCl-susceptible MRSA isolates from meat samples. The growth of 12 MRSA and 10 non-MRSA strains was measured in Mueller-Hinton (MH) broth supplemented with 2.5%, 4%, 6.5%, and 7.5% NaCl. Selective agents, including aztreonam, polymyxin B, NaCl, nalidixic acid, and NaN3, were determined for their inhibitory effect to MRSA and non-MRSA strains in MH broth. Based on these data, a two-step enrichment method was developed to recover both NaCl-susceptible and -resistant MRSA isolates in meat products. Comparing to the enrichment method that only used MH broth supplemented with 6.5% NaCl, five additional NaCl-susceptible MRSA isolates were recovered from 92 retail ground pork samples by this newly developed two-step enrichment method. To the best of our knowledge, this is the first study that considers NaCl-susceptible MRSA recovery from ground pork samples. The application of this new enrichment method might expand the diversity of MRSA isolates recovered from various samples.

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