High prevalence of antibodies to human herpesvirus 8 in relatives of patients with classic Kaposi's sarcoma from Sardinia

A survey for antibodies to a recombinant small viral capsid antigen (sVCA) of human herpesvirus type 8 (HHV‐8) was conducted in Sardinia, one of the world's highest incidence areas for classic Kaposi's sarcoma (KS). Prevalence of antibodies to HHV‐8 sVCA was greatest in patients with KS (95%), followed by family members (39%) and a Sardinian control population age‐ and sex‐matched to the relatives (11%). Within families, prevalence of antibodies was about equal among spouses, children, and siblings of KS patients, a finding that raises the possibilities of intrafamilial person‐to‐person or vertical transmission. Antibodies were detected 2–3 times more frequently in males than in females. The data show that prevalence of antibodies to HHV‐8 sVCA correlates with the distribution of classic KS in a high‐ incidence area. Clustering of seroprevalence within some families suggests the presence of familial risk factors for active HHV‐8 infection

Intraday Patterns in the Cross-section of Stock Returns

Motivated by the literature on investment flows and optimal trading, we examine intraday predictability in the cross-section of stock returns. We find a striking pattern of return continuation at half-hour intervals that are exact multiples of a trading day, and this effect lasts for at least 40 trading days. Volume, order imbalance, volatility, and bid-ask spreads exhibit similar patterns, but do not explain the return patterns. We also show that short-term return reversal is driven by temporary liquidity imbalances lasting less than an hour and bid-ask bounce. Timing trades can reduce execution costs by the equivalent of the effective spread

The Quality vs. the Quantity of Schooling: What Drives Economic Growth?

This paper challenges Hanushek and Woessmann’s [2008] contention that the quality and not the quantity of schooling determines a nation’s rate of economic growth. I first show that their statistical analysis is flawed. I then show that when a nation’s average test scores and average schooling attainment are included in a national income model, both measures explain income differences, but schooling attainment has greater statistical significance. The high correlation between a nation’s average schooling attainment, cumulative investment in schooling, and average tests scores indicates that average schooling attainment implicitly measures the quality as well as the quantity of schooling

Physical Capital Accumulation in Asia-12: Past Trends and Future Projections

The pace of capital accumulation in East Asia has simply been stunning. In this paper, we investigate sources of this fast accumulation and make projections for the future to see if the trend is likely to continue. East Asian economies under consideration are the People's Republic of China; Hong Kong, China; Indonesia; the Republic of Korea; Malaysia, the Philippines; Singapore; Taipei,China; Thailand; and Viet Nam, including India and Pakistan from South Asia. We estimate a "convergence" equation for physical capital per capita, which is derived from an open economy growth model, using a pooled cross-country, across-decade sample of the entire world. Based on the estimation results, we decompose past growth in physical capital per capita of the emerging Asian economies. We also conduct projections for the next two decades and study determinants of the investment rate for those economies

The Short-Time Behaviour of VIX Implied Volatilities in a Multifactor Stochastic Volatility Framework

We consider a modelling setup where the VIX index dynamics are explicitly computable as a smooth transformation of a purely diffusive, multidimensional Markov process. The framework is general enough to embed many popular stochastic volatility models. We develop closed-form expansions and sharp error bounds for VIX futures, options and implied volatilities. In particular, we derive exact asymptotic results for VIX implied volatilities, and their sensitivities, in the joint limit of short time-to-maturity and small log-moneyness. The obtained expansions are explicit, based on elementary functions and they neatly uncover how the VIX skew depends on the specific choice of the volatility and the vol-of-vol processes. Our results are based on perturbation techniques applied to the infinitesimal generator of the underlying process. This methodology has been previously adopted to derive approximations of equity (SPX) options. However, the generalizations needed to cover the case of VIX options are by no means straightforward as the dynamics of the underlying VIX futures are not explicitly known. To illustrate the accuracy of our technique, we provide numerical implementations for a selection of model specifications

A Subset of Replication Proteins Enhances Origin Recognition and Lytic Replication by the Epstein-Barr Virus ZEBRA Protein

ZEBRA is a site-specific DNA binding protein that functions as a transcriptional activator and as an origin binding protein. Both activities require that ZEBRA recognizes DNA motifs that are scattered along the viral genome. The mechanism by which ZEBRA discriminates between the origin of lytic replication and promoters of EBV early genes is not well understood. We explored the hypothesis that activation of replication requires stronger association between ZEBRA and DNA than does transcription. A ZEBRA mutant, Z(S173A), at a phosphorylation site and three point mutants in the DNA recognition domain of ZEBRA, namely Z(Y180E), Z(R187K) and Z(K188A), were similarly deficient at activating lytic DNA replication and expression of late gene expression but were competent to activate transcription of viral early lytic genes. These mutants all exhibited reduced capacity to interact with DNA as assessed by EMSA, ChIP and an in vivo biotinylated DNA pull-down assay. Over-expression of three virally encoded replication proteins, namely the primase (BSLF1), the single-stranded DNA-binding protein (BALF2) and the DNA polymerase processivity factor (BMRF1), partially rescued the replication defect in these mutants and enhanced ZEBRA's interaction with oriLyt. The findings demonstrate a functional role of replication proteins in stabilizing the association of ZEBRA with viral DNA. Enhanced binding of ZEBRA to oriLyt is crucial for lytic viral DNA replication

Model complexity and out-of-sample performance: evidence from S&P 500 index returns

We apply a range of out-of-sample specification tests to more than forty competing stochastic volatility models to address how model complexity affects out-of-sample performance. Using daily S&P 500 index returns, model confidence set estimations provide strong evidence that the most important model feature is the non-affinity of the variance process. Despite testing alternative specifications during the turbulent market regime of the global financial crisis of 2008, we find no evidence that either finite- or infinite-activity jump models or other previously proposed model extensions improve the out-of-sample performance further. Applications to Value-at-Risk demonstrate the economic significance of our results. Furthermore, the out-of-sample results suggest that standard jump diffusion models are misspecified

Impact of Population Aging on Asia’s Future Growth

The demographic dividend that contributed substantially to economic growth in developing Asia in the past is dissipating. Population aging affects growth through savings, capital accumulation, labor force participation, and total factor productivity. We examined the impact of aging on those four channels in 12 developing Asian economies that collectively make up the bulk of the region's population and output. We then made projections about the effects of demographic change on the economic growth of the 12 from 2011 to 2020 and from 2021 to 2030. Our results indicate that there will be a sizable adverse economic impact where population aging is more advanced

On the Valuation of Fader and Discrete Barrier Options in Heston's Stochastic Volatility Model

We focus on closed-form option pricing in Heston's stochastic volatility model, in which closed-form formulas exist only for few option types. Most of these closed-form solutions are constructed from characteristic functions. We follow this approach and derive multivariate characteristic functions depending on at least two spot values for different points in time. The derived characteristic functions are used as building blocks to set up (semi-) analytical pricing formulas for exotic options with payoffs depending on finitely many spot values such as fader options and discretely monitored barrier options. We compare our result with different numerical methods and examine accuracy and computational times