Pulsar timing arrays and the challenge of massive black hole binary astrophysics

Pulsar timing arrays (PTAs) are designed to detect gravitational waves (GWs) at nHz frequencies. The expected dominant signal is given by the superposition of all waves emitted by the cosmological population of supermassive black hole (SMBH) binaries. Such superposition creates an incoherent stochastic background, on top of which particularly bright or nearby sources might be individually resolved. In this contribution I describe the properties of the expected GW signal, highlighting its dependence on the overall binary population, the relation between SMBHs and their hosts, and their coupling with the stellar and gaseous environment. I describe the status of current PTA efforts, and prospect of future detection and SMBH binary astrophysics.Comment: 18 pages, 4 figures. To appear in the Proceedings of the 2014 Sant Cugat Forum on Astrophysics. Astrophysics and Space Science Proceedings, ed. C.Sopuerta (Berlin: Springer-Verlag

Bending the Curve in Cardiovascular Disease Mortality: Bethesda + 40 and beyond

More than 40 years after the 1978 Bethesda Conference on the Declining Mortality from Coronary Heart Disease provided the scientific community with a blueprint for systematic analysis to understand declining rates of coronary heart disease, there are indications the decline has ended or even reversed despite advances in our knowledge about the condition and treatment. Recent data show a more complex situation, with mortality rates for overall cardiovascular disease, including coronary heart disease and stroke, decelerating, whereas those for heart failure are increasing. To mark the 40th anniversary of the Bethesda Conference, the National Heart, Lung, and Blood Institute and the American Heart Association cosponsored the "Bending the Curve in Cardiovascular Disease Mortality: Bethesda + 40" symposium. The objective was to examine the immediate and long-term outcomes of the 1978 conference and understand the current environment. Symposium themes included trends and future projections in cardiovascular disease (in the United States and internationally), the evolving obesity and diabetes epidemics, and harnessing emerging and innovative opportunities to preserve and promote cardiovascular health and prevent cardiovascular disease. In addition, participant-led discussion explored the challenges and barriers in promoting cardiovascular health across the lifespan and established a potential framework for observational research and interventions that would begin in early childhood (or ideally in utero). This report summarizes the relevant research, policy, and practice opportunities discussed at the symposium

Clinical role of coronary magnetic resonance angiography in the diagnosis of anomalous coronary arteries.

Though rare, anomalous coronary artery disease is a well-known cause of myocardial ischemia and sudden death among children and young adults. The projectional nature of conventional x-ray angiography often leads to difficulty in the definition of anomalous vessels. Studies have now documented the high accuracy of coronary magnetic resonance angiography (MRA) for the noninvasive detection and definition of anomalous coronary arteries among patients with suspected anomalous coronary arteries of congenital conditions associated with anomalous coronary arteries. With increasing clinical experience, coronary MRA will likely emerge as the gold standard for the diagnosis of this condition