Genetic ancestry in Puerto Rican afro-descendants illustrates diverse histories of African diasporic populations.

Objectives: Genetic studies of contemporary Puerto Ricans reflect a demographic history characterized by admixture between Indigenous American, African, and European peoples. While previous studies provide genetic perspectives on the general Puerto Rican population, less is known about the island's sub-populations, specifically Afro-Puerto Ricans.

Materials And Methods: In this study, the genetic ancestry of Afro-Puerto Ricans is characterized and compared to other Caribbean populations.

Promise of Future Searches for Cosmic Topology.

The shortest distance around the Universe through us is unlikely to be much larger than the horizon diameter if microwave background anomalies are due to cosmic topology. We show that observational constraints from the lack of matched temperature circles in the microwave background leave many possibilities for such topologies. We evaluate the detectability of microwave background multipole correlations for sample cases.

Gravitational Glint: Detectable Gravitational Wave Tails from Stars and Compact Objects.

Observations of a merging neutron star binary in both gravitational waves, by the Laser Interferometer Gravitational-Wave Observatory (LIGO), and across the spectrum of electromagnetic radiation, by myriad telescopes, have been used to show that gravitational waves travel in vacuum at a speed that is indistinguishable from that of light to within one part in a quadrillion. However, it has long been expected mathematically that, when electromagnetic or gravitational waves travel through vacuum in a curved spacetime, the waves develop tails that travel more slowly. The associated signal has been thought to be undetectably weak.

Helical magnetic fields from sphaleron decay and baryogenesis.

Many models of baryogenesis rely on anomalous particle physics processes to give baryon number violation. By numerically evolving the electroweak equations on a lattice, we show that baryogenesis in these models creates helical cosmic magnetic fields, though the helicity created is smaller than earlier analytical estimates. After a transitory period, electroweak dynamics is found to conserve the Chern-Simons number and the total electromagnetic helicity.

Is the low-l microwave background cosmic?

The large-angle (low-l) correlations of the cosmic microwave background exhibit several statistically significant anomalies compared to the standard inflationary cosmology. We show that the quadrupole plane and the three octopole planes are far more aligned than previously thought (99.9% C.