Potential and perils: paths to protecting lunar sites of extraordinary scientific importance (SESIs) for astronomy before it is too late.

The Moon presents unique opportunities for high-impact astronomy that could enhance our understanding of our solar system, the possibility of life beyond Earth, and the evolution of the universe. A handful of locations on the lunar surface are 'sites of extraordinary scientific importance' (SESIs) for such studies, presenting opportunities for astronomical research unmatched anywhere else. For instance, the farside of the Moon, the most radio-quiet location in the inner solar system, could allow for the emplacement of telescopes to study the cosmic Dark Ages in ways that are impossible elsewhere.

Concentrated lunar resources: imminent implications for governance and justice.

Numerous missions planned for the next decade are likely to target a handful of small sites of interest on the Moon's surface, creating risks of crowding and interference at these locations. The Moon presents finite and scarce areas with rare topography or concentrations of resources of special value. Locations of interest to science, notably for astronomy, include the Peaks of Eternal Light, the coldest of the cold traps and smooth areas on the far side.

GALAXY EVOLUTION. An over-massive black hole in a typical star-forming galaxy, 2 billion years after the Big Bang.

Supermassive black holes (SMBHs) and their host galaxies are generally thought to coevolve, so that the SMBH achieves up to about 0.2 to 0.5% of the host galaxy mass in the present day.

The novel anticoagulants: the surgeons' prospective.

Anticoagulants can complicate the approach to the management of patients undergoing operative interventions. We review new anticoagulants that have been introduced recently to the market or that are undergoing investigations for treatment of nonvalvular atrial fibrillation and venous thromboembolism prophylaxis: Dabigatran, rivaroxaban, apixiban, and edoxaban.

Missing baryons and the warm-hot intergalactic medium.

Stars and gas in galaxies, hot intracluster medium, and intergalactic photo-ionized gas make up at most half of the baryons that are expected to be present in the universe. The majority of baryons are still missing and are expected to be hidden in a web of warm-hot intergalactic medium. This matter was shock-heated during the collapse of density perturbations that led to the formation of the relaxed structures that we see today.

The mass of the missing baryons in the X-ray forest of the warm-hot intergalactic medium.

Recent cosmological measurements indicate that baryons comprise about four per cent of the total mass-energy density of the Universe, which is in accord with the predictions arising from studies of the production of the lightest elements. It is also in agreement with the actual number of baryons detected at early times (redshifts z > 2). Close to our own epoch (z < 2), however, the number of baryons detected add up to just over half (approximately 55 per cent) of the number seen at z > 2 (refs 6-11), meaning that about approximately 45 per cent are 'missing'.

The far-ultraviolet signature of the 'missing' baryons in the Local Group of galaxies.

The number of baryons detected in the low-redshift (z < 1) Universe is far smaller than the number detected in corresponding volumes at higher redshifts. Simulations of the formation of structure in the Universe show that up to two-thirds of the 'missing' baryons may have escaped detection because of their high temperature and low density. One of the few ways to detect this matter directly is to look for its signature in the form of ultraviolet absorption lines in the spectra of background sources such as quasars.