We provide evidence of a drastic drop in stock run-ups of U.S. target firms preceding merger and acquisition (M&A) announcements over the past decades. The median target run-up declines from approximately 10% in the 1980s to 2% after 2010. The trend in target run-ups cannot be fully explained by deal or firm characteristics associated with deal anticipation. However, it disappears after controlling for changes in the strength of U.S. insider trading regulation over the research period. Further analyses corroborate our conclusion that more stringent insider trading regulation is the most likely explanation for the reduction in target run-ups.

BACKGROUND: In recent years social networking sites (SNSs) have grown rapidly in popularity. The popularity of these sites, along with their interactive functions, offer a novel environment in which to deliver health promotion messages. The aim of this paper is to examine the extent to which SNSs are currently being used for sexual health promotion and describe the breadth of these activities. METHODS: We conducted a systematic search of published scientific literature, electronic sources (general and scientific search engines, blogs) and SNSs (Facebook, MySpace) to identify existing sexual health promotion activities using SNSs. Health promotion activities were eligible for inclusion if they related to sexual health or behaviour, utilised one or more SNSs, and involved some element of health promotion. Information regarding the source and type of health promotion activity, target population and site activity were extracted. RESULTS: 178 sexual health promotion activities met the inclusion criteria and were included in the review; only one activity was identified through a traditional systematic search of the published scientific literature. Activities most commonly used one SNS, were conducted by not-for-profit organisations, targeted young people and involved information delivery. Facebook was the most commonly used SNS (used by 71% of all health promotion activities identified), followed by MySpace and Twitter. Seventy nine percent of activities on MySpace were considered inactive as there had been no online posts within the past month, compared to 22% of activities using Facebook and 14% of activities using Twitter. The number of end-users and posts in the last seven days varied greatly between health promotion activities. CONCLUSIONS: SNSs are being used for sexual health promotion, although the extent to which they are utilised varies greatly, and the vast majority of activities are unreported in the scientific literature. Future studies should examine the key factors for success among those activities attracting a large and active user base, and how success might be measured, in order to guide the development of future health promotion activities in this emerging setting.

In an uncertain environment, probabilities are key to predicting future events and making adaptive choices. However, little is known about how humans learn such probabilities and where and how they are encoded in the brain, especially when they concern more than two outcomes. During functional magnetic resonance imaging (fMRI), young adults learned the probabilities of uncertain stimuli through repetitive sampling. Stimuli represented payoffs and participants had to predict their occurrence to maximize their earnings. Choices indicated loss and risk aversion but unbiased estimation of probabilities. BOLD response in medial prefrontal cortex and angular gyri increased linearly with the probability of the currently observed stimulus, untainted by its value. Connectivity analyses during rest and task revealed that these regions belonged to the default mode network. The activation of past outcomes in memory is evoked as a possible mechanism to explain the engagement of the default mode network in probability learning. A BOLD response relating to value was detected only at decision time, mainly in striatum. It is concluded that activity in inferior parietal and medial prefrontal cortex reflects the amount of evidence accumulated in favor of competing and uncertain outcomes.

This article is motivated by uncertainty in experimental determinations of the gravitational constant, G, and numerous anomalies of up to 0.5 percent in Newtonian gravitational force on bodies within the solar system. The analysis sheds new light through six natural experiments within the solar system, which draw on published reports and astrophysical databases, and involve laboratory determinations of G, orbital dynamics of the planets and the moons of Earth and Mars, and non-gravitational acceleration (NGA) of ‘Oumuamua and comets. In each case, values are known for all variables in Newton’s Law F=G·M·mR2, except for the gravitational constant, G. Analyses determine the gravitational constant’s observed value, G^, which—across the six settings—varies with the mass of the smaller, moving body, m, so that G^=G×0.998+0.00016×lnm. While further work is required, this examination shows a scale-related Newtonian gravity effect at scales from benchtop to Solar System, which contributes to the understanding of symmetry in gravity and has possible implications for Newton’s Laws, dark matter, and formation of structure in the universe.

A bottom-up measure of aggregate investment plans, namely, aggregate expected investment growth (AEIG) can negatively predict market returns. At the one-year horizon, the adjusted in-sample R2 is 18.2% and the out-of-sample R2 is 14.4%. The return predictive power is robust after controlling for standard macroeconomic return predictors and proxies for investor sentiment. Further analyses suggest that the predictive ability of AEIG is at least partially driven by the time-varying risk premium. These findings lend support to neoclassical models with investment lags.

There have been claims that British capital was not well deployed in Victorian Britain. There was, allegedly, a lack of support for new and dynamic companies in comparison to the situation in Germany and the US. We find no evidence to support these claims. The London Stock Exchange welcomed young, old, domestic, and foreign firms. It provided funds to firms in old, existing industries as well as patenting firms in ‘new‐tech’ industries at similar costs of capital. If investors did show a preference for older and foreign firms, it was because those firms offered investors better long‐run performance. In addition, we show some evidence that investors who worked in the same industry and lived close to the firm going public were allotted more shares in high‐quality initial public offerings.

A variable purchase option (VPO) is a call option issued by a company on a stochastic rather than on a fixed number of its ordinary shares. This paper tests the arbitrage-free pricing model of Handley (2000) using a transactions dataset of actual market prices covering the five VPOs traded on the Australian Stock Exchange during the six-year period from May 1992 to May 1998. It is initially found that the model systematically overprices VPOs. A subsequent case-based explanatory analysis of the pricing errors, however, shows that this mispricing substantially disappears under different estimates of two key parameters. The results are consistent with investors using risk-adjusted discount rates rather than the risk-free rate in valuing the bond component of the VPO and, when material, using a narrow range of volatility estimates, rather than historic volatility estimates, in valuing the option component of the VPO.