Multimodal Imaging Brain Markers in Early Adolescence Are Linked with a Physically Active Lifestyle.

The World Health Organization promotes physical exercise and a healthy lifestyle as means to improve youth development. However, relationships between physical lifestyle and human brain development are not fully understood. Here, we asked whether a human brain-physical latent mode of covariation underpins the relationship between physical activity, fitness, and physical health measures with multimodal neuroimaging markers.

An unethical optimization principle.

If an artificial intelligence aims to maximize risk-adjusted return, then under mild conditions it is disproportionately likely to pick an unethical strategy unless the objective function allows sufficiently for this risk. Even if the proportion of available unethical strategies is small, the probability of picking an unethical strategy can become large; indeed, unless returns are fat-tailed tends to unity as the strategy space becomes large. We define an unethical odds ratio, (capital upsilon), that allows us to calculate from , and we derive a simple formula for the limit of as the strategy space becomes large.

Individual versus systemic risk and the Regulator's Dilemma.

The global financial crisis of 2007-2009 exposed critical weaknesses in the financial system. Many proposals for financial reform address the need for systemic regulation--that is, regulation focused on the soundness of the whole financial system and not just that of individual institutions. In this paper, we study one particular problem faced by a systemic regulator: the tension between the distribution of assets that individual banks would like to hold and the distribution across banks that best supports system stability if greater weight is given to avoiding multiple bank failures.