The Basel III Accord requires countercyclical capital buffers to protect the banking system against potential losses associated with excessive credit growth and buildups of systemic risk. In this paper, I provide a rationale for time-varying capital requirements in a dynamic general equilibrium setting. An optimal policy trades off reduced inefficient lending with reduced liquidity provision. Quantitatively, I find that the optimal Ramsey policy requires a capital ratio that mostly varies between 4% and 6% and depends on economic growth, bank supply of credit, and asset prices. Specifically, a one standard deviation increase in the bank credit-to-GDP ratio (GDP) translates into a 0.1% (0.7%) increase in capital requirements, while each standard deviation increase in the liquidity premium leads to a 0.1% decrease. The welfare gain from implementing this dynamic policy is large when compared to the gain from having an optimal fixed capital requirement.
Using the market for initial coin offerings (ICOs) as a laboratory, we provide evidence that entrepreneurs use retention to alleviate information asymmetry. The underlying technology and the absence of regulation make the ICO market well suited to study this question empirically. Using a hand-collected data set, we show that ICO issuers that retain a larger fraction of their tokens are more successful in their funding efforts and are more likely to develop a working product. Moreover, we find that retention is a stronger signal when markets are crowded, and investors do not have as much time to conduct due diligence. This paper was accepted by Will Cong, Special Issue of Management Science: Blockchains and crypto economics. Supplemental Material: The data files are available at https://doi.org/10.1287/mnsc.2022.4631 .
Food and water are main sources of human exposure to arsenic. It is important to determine arsenic species in food because toxicities of arsenic vary greatly with its chemical speciation. Extensive research has focused on high concentrations of arsenic species in marine organisms. The concentrations of arsenic species in freshwater fish are much lower, and their determination presents analytical challenges. We summarize in this review the current state of knowledge on arsenic speciation in freshwater fish and discuss challenges and research needs. Fish samples are typically homogenized, and arsenic species extracted using water/methanol with the assistance of sonication and enzyme treatment. Arsenic species in the extracts are commonly separated using high performance liquid chromatography (HPLC) and detected using inductively coupled plasma mass spectrometry (ICPMS). Electrospray ionization tandem mass spectrometry (ESI MS/MS), used in combination with HPLC and ICPMS, provides complementary information for the identification and characterization of arsenic species. The methods and perspectives discussed in this review, covering sample preparation, chromatography separation, and mass spectrometry detection, are directed to arsenic speciation in freshwater fish and also applicable to studies of other food items. Despite progresses made in arsenic speciation analysis, a large fraction of total arsenic in freshwater fish remains unidentified. It is challenging to identify and quantify arsenic species present in complex sample matrices at very low concentrations. Further research is needed to improve the extraction efficiency, chromatographic resolution, detection sensitivity, and characterization capability.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.