To examine the epidemiology of rotaviruses in Buenos Aires, Argentina, we screened 1,212 stool samples from children with diarrhea in the southern district of Buenos Aires from 1999 to 2003. We identified 187 samples (15.4%) that were positive for group A rotavirus by use of antigen enzyme-linked immunosorbent assay. Among these specimens, 112 were available for typing: 93 (83.0%) were single-t...

We study the returns to investing in VIX futures and VIX Exchange Traded Notes (ETNs). We document a substantial negative return premium for both ETNs and the futures. For example, the a constant maturity portfolio of one-month VIX futures loses about 30% per year over our sample period (2006-2013). We propose an equilibrium model to explain these negative returns. In this model, increases in v...

A trivariate vector autoregression time series process, based on a present-value land price model, is used to decompose Iowa farmland prices into fundamental and non-fundamental components. A recent study, by Falk and Lee (1998), found that non-fundamental shocks are an important source of volatility in farmland prices and it was interpreted that these price movements were due to fads not specu...

We provide theory for calculating bounds on both the value of an individual’s human capital and the return on an individual’s human capital, given knowledge of the process governing earnings and financial asset returns. We calculate bounds using U.S. data on male earnings and financial asset returns. The large idiosyncratic component of earnings risk implies that bounds on values and returns ar...

In this paper, we develop an agency-theoretic extension of the Lucas asset pricing model and examine the resulting asset price dynamics. In the model, an agent of the firm can expand or contract the firm’s output and dividend payments in response to exogenous shocks, although expansions become increasingly costly for the agent to maintain. Analysis of numerical simulations shows that the time-s...

Recent asset-pricing models incorporate jump risk through Lévy processes in addition to diffusive risk. This paper studies how to detect stochastic arrivals of small and big Lévy jumps with new nonparametric tests. The tests allow for robust analysis of their separate characteristics and facilitate better estimation of return dynamics. Empirical evidence of both small and big jumps based on the...

We model sovereign debt in the absence of a bankruptcy code. Threat of trade sanctions and seizure of exports by the lenders are the drivers of enforcement of sovereign debt contracts.The borrower takes these potential actions into account when choosing optimal voluntary default and debt capacity. We obtain a closedform solution for the sovereign yield spreads that depend on the costs of sancti...

This paper revisits the time-series relation between the conditional risk premium and variance of the equity market portfolio. The main innovation is that we construct a measure of the ex ante equity market risk premium using corporate bond yield spread data. This measure is forward-looking and does not rely critically on either realized equity returns or instrumental variables. We find strong ...

We propose a local adaptive multiplicative error model (MEM) accommodating timevarying parameters. MEM parameters are adaptively estimated based on a sequential testing procedure. A data-driven optimal length of local windows is selected, yielding adaptive forecasts at each point in time. Analyzing one-minute cumulative trading volumes of five large NASDAQ stocks in 2008, we show that local win...

This paper provides an empirical analysis of the trading behavior and the impact of new investors on the bubble surrounding the Baosteel call warrant, the first derivative traded in China after a nine-year suspension. First, we find that the new investors initiated the bubble. Second, echoing common wisdom, we empirically show that the continuous entries of new investors sustained the bubble. T...