A lockup period for investment in a hedge fund is a time period after making the investment during which the investor cannot freely redeem his investment. It is routine to have a one-year lockup period, but recently the requested lockup periods have grown longer. Assuming that the investor will rebalance his portfolio of hedge funds on a yearly basis, if permitted, we define the annual lockup p...

In the traditional portfolio model, investors calculate the expected return of assets and the covariance matrix for optimal asset allocation. This paper divides market sentiment period into three states and selectes the securities in the Chinese stock market to construct portfolios. We implement both the Fama-French five-factor model and the robust median covariance matrix approach for predicti...

Smart beta exchange-traded funds (SB ETFs) have caught the attention of investors due to their supposed ability offer a better risk–return trade-off than traditionally structured passive indices. Yet, research covering performance SB ETFs benchmarked traditional cap-weighted market indices remains relatively scarce. There is lack empirical evidence enforcing this phenomenon. Extending work Glus...

Recently, the notion of return words has appeared in various branches of mathematics, for instance in Symbolic Dynamical Systems and Number Theory. This mathematical tool has been introduced by Durand [2] in order to obtain a nice characterization of primitive substitutive sequences. Roughly speaking, for a given factor w of the infinite word u, a return word of w is a segment between two succe...

Serious brachial plexus injury after median sternotomy is uncommon. However, affected patients experience considerable morbidity and their return to regular employment is often delayed. The pathogenesis of the injury is multifactorial. Wide sternal retraction is the major etiologic factor. Management is primarily conservative and should be guided by a team experienced in upper limb and hand sur...