Description: Author(s): Srujan Meesala, Young-Ik Sohn, Benjamin Pingault, Linbo Shao, Haig A. Atikian, Jeffrey Holzgrafe, Mustafa Gündoğan, Camille Stavrakas, Alp Sipahigil, Cleaven Chia, Ruffin Evans, Michael J. Burek, Mian Zhang, Lue Wu, Jose L. Pacheco, John Abraham, Edward Bielejec, Mikhail D. Lukin, Mete Atatüre, and Marko Lončar Here, the authors tune the color of light emitted by single-atom imperfections (silicon vacancy color centers) inside a diamond. Such tunable imperfections can be networked together to build a quantum internet, where information can be securely exchanged using the laws of quantum physics. One problem is that all the centers need to emit at precisely the same color or wavelength. The authors overcome this challenge by placing color centers inside a diamond nanostring. By adjusting the tension in the string, atoms are stretched inside the crystal and tune the center to emit photons of a desired wavelength. The tuning method involves bending the string with a force controlled handily with an electrical voltage. A symphony of such tunable diamond strings could serve as the backbone of a future quantum internet. [Phys. Rev. B 97, 205444] Published Tue May 29, 2018

Description: Background: Herbivore coexistence on the Late Cretaceous island continent of Laramidia has been a topic of great interest, stemming from the paradoxically high diversity and biomass of these animals in relation to the relatively small landmass available to them. Various hypotheses have been advanced to account for these facts, of which niche partitioning is among the most frequently invoked. However, despite its wide acceptance, this hypothesis has not been rigorously tested. This study uses the fossil assemblage from the Dinosaur Park Formation of Alberta as a model to investigate whether niche partitioning facilitated herbivorous dinosaur coexistence on Laramidia. Specifically, the question of feeding height stratification is examined in light of the role it plays in facilitating modern ungulate coexistence. Results: Most herbivorous dinosaur species from the Dinosaur Park Formation were restricted to feeding no higher than approximately 1 m above the ground. There is minimal evidence for feeding height partitioning at this level, with ceratopsids capable of feeding slightly higher than ankylosaurs, but the ecological significance of this is ambiguous. Hadrosaurids were uniquely capable of feeding up to 2 m quadrupedally, or up to 5 m bipedally. There is no evidence for either feeding height stratification within any of these clades, or for change in these ecological relationships through the approximately 1.5 Ma record of the Dinosaur Park Formation. Conclusions: Although we cannot reject the possibility, we find no good evidence that feeding height stratification, as revealed by reconstructed maximum feeding heights, played an important role in facilitating niche partitioning among the herbivorous dinosaurs of Laramdia. Most browsing pressure was concentrated in the herb layer, although hadrosaurids were capable of reaching shrubs and low-growing trees that were out of reach from ceratopsids, ankylosaurs, and other small herbivores, effectively dividing the herbivores in terms of relative abundance. Sympatric hadrosaurids may have avoided competing with one another by feeding differentially using bipedal and quadrupedal postures. These ecological relationships evidently proved to be evolutionarily stable because they characterize the herbivore assemblage of the Dinosaur Park Formation through time. If niche partitioning served to facilitate the rich diversity of these animals, it may have been achieved by other means in addition to feeding height stratification. Consideration of other feeding height proxies, including dental microwear and skull morphology, may help to alleviate problems of underdetermination identified here.

Description: Background: Very preterm birth (