Editors' Choice

Science  17 May 2019:
Vol. 364, Issue 6441, pp. 646
  1. Exoplanets

    Interferometry spots an exoplanet

    1. Keith T. Smith

    The GRAVITY Collaboration used the Very Large Telescope, located in the Atacama Desert of northern Chile, to observe the star HR 8799 and one of its planets.

    PHOTO: G. H√úDEPOHL (ATACAMAPHOTO.COM)/ESO/CC-BY

    Optical interferometry combines the light from multiple telescopes to reach very high angular resolution but is challenging to apply to high-contrast sources such as an exoplanet orbiting a star. The GRAVITY Collaboration observed the star HR 8799 and one of its planets, HR 8799 e, using an optical interferometer fed by four 8-meter telescopes. They detected the planet, measured its position more precisely than has been done using previous methods, and extracted a near-infrared spectrum that constrains the composition of its atmosphere. This is the first exoplanet to be detected with interferometry. Although HR 8799 e was already known, the interferometry technique could be used to refine the orbits and spectra of directly imaged exoplanets.

    Astron. Astrophys. 623, L11 (2019).

  2. Mutation

    DNA damage and parental age

    1. Laura M. Zahn

    Mutations in the sperm and eggs of humans have been attributed to errors in DNA replication. More than 75% of human germline mutations are paternal in origin. This is thought to be a result of male gametes undergoing more rounds of cell division than female gametes and thus having a greater probability of replication error. Gao et al. examined datasets of de novo mutations in the human germline and found that the mutation bias is not driven by spermatogenesis. They observed a surprising degree of C-to-G transversions and CpG transitions, indicative of DNA damage. The authors deduced that most mutations in early embryos are more likely to result from factors associated with maternal age at conception and accumulated damage in oocytes and embryos than from replication error.

    Proc. Natl. Acad. Sci. U.S.A. 116, 9491 (2019).

  3. Kidney Disease

    A pharmacological hat trick

    1. Paula A. Kiberstis

    The number of people with type 2 diabetes (T2D) may reach 510 million by the year 2030, a trend largely driven by the global rise in obesity rates. Because T2D often compromises kidney function, the number of people with kidney failure is also expected to rise dramatically. A new study suggests that a drug already in clinical use for T2D may provide multiple health benefits to such patients. Canagliflozin lowers blood glucose levels by blocking reabsorption of glucose in the kidney. In a large randomized trial of patients with T2D and chronic kidney disease, Perkovic et al. found that those receiving canagliflozin were 30% less likely to develop end-stage kidney disease and 20 to 30% less likely to develop cardiovascular disease than those receiving placebo.

    N. Engl. J. Med. 10.1056/NEJMoa1811744 (2019).

  4. Atomic Physics

    Superresolving atomic densities

    1. Jelena Stajic

    Quantum gas microscopes provide information about the occupancy of individual optical lattice sites. However, the resolution is limited by the wavelength of the imaging light. Two related superresolution schemes now enable researchers to glean even finer details of the atomic density distribution. McDonald et al. and Subhankar et al. studied one-dimensional arrays of ultracold atoms. A well-chosen perturbation provided a narrow window onto a specific position; when information from different positions was pieced together, the researchers were able to reconstruct the atomic density with a resolution of a fraction of the optical wavelength. The schemes were effective in capturing atomic dynamics and are expected to be applicable to a wide range of atomic and molecular species.

    Phys. Rev. X 9, 021001, 021002 (2019).

  5. Mutualism

    Size matters

    1. Sacha Vignieri

    Burying beetles, Nicrophorus vespilloides, commonly carry mites.

    PHOTO: LES GIBBON/ALAMY STOCK PHOTO

    A mutualistic relationship exists between species when they both benefit from the other's presence. Yet sometimes such relationships can become antagonistic. To understand how mutualisms are poised, Sun et al. investigated the interactions between a carrion beetle and its associated mite. The mites depend on the beetles to carry them to carcasses, where both species breed. The authors found that the beetles benefit from the mites' presence because the mites raise the body temperature of the beetles, which allows small individuals to behave more competitively. Large beetles, because of their sheer size, already have a competitive advantage and gain little from the mites. Instead, the bigger beetles experience reduced fitness because they have to share breeding resources with the mites. Thus, whether the relationship between the two species is antagonistic or mutualistic depends entirely on differences between the beetles' sizes.

    Evol. Lett. 3, 185 (2019).

  6. Neuroscience

    Training for cognitive skills

    1. Pamela J. Hines

    Play your notes and nothing extra. Wait during your measures of rest. Watch the conductor and synchronize with your neighbors. Such attention and sensorimotor skills are key to performing music as part of a group, whether orchestral or choral or a marching band. Not everyone, however, has the time and interest to become a professional musician. Fasano et al. tested the effect of a short orchestral training program, spanning 10 sessions over 3 months, on a group of psychologically normal schoolchildren in Italy. Children in this brief program improved on measures of inhibitory control and hyperactivity. The results suggest new, and fun, ways to help children manage their own hyperactive behaviors.

    Front. Psychol. 10, 750 (2019).

  7. Robotics

    UV light as your guide

    1. Marc S. Lavine

    Navigation by using global positioning satellites or magnetic fields or motion tracking by using inertial sensors or gyroscopes can be hindered in dense urban settings or suffer from poor resolution and drift. Dupeyroux et al. drew inspiration from desert ants, which use a combination of stride, visual cues of motion, and polarization of sunlight to track the positions of their nest and sources of food. They developed a robot equipped with a 2-pixel compass that was able to use ultraviolet (UV) light and path integration to maintain a straight heading under both clear and mixed sky conditions, with only a small deviation in overall angle, and was even able to determine its heading under a foliage canopy. The authors also developed a waterproof, single-pixel version of the sensor for use under water.

    Rob. Auton. Syst. 117, 40 (2019).