Editors' Choice

Science  07 Oct 2016:
Vol. 354, Issue 6308, pp. 78
  1. Invasive Species

    The problem with our predators

    1. Sacha Vignieri

    Mammalian predators can make great pets, but as invasive species, they have big negative impacts on natives.


    In our modern world, in which people move themselves and their goods across the entire globe, species invasions have become commonplace. Such invasions have varying degrees of impacts, with some species actually performing important functional replacements and others driving native species to extinction. Doherty et al. look at one of the most damaging groups, invasive mammalian predators. Just as predators in their own habitats have strong structuring effects, invading predators have large impacts on native species. Such effects are strongest and most damaging in island environments. Finding that islands should be the highest priority for action provides some hope for the potential to decrease predator impacts through removal, an option often frowned upon in continental areas, where invasive predators may be our own companions.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1602480113 (2016).

  2. Psychology

    Learning physics through vectors

    1. Gilbert Chin

    Long before they first learn about Newtonian mechanics, children develop an understanding of how objects interact. They learn that taller objects can hide shorter objects (visual occlusion) and that two objects cannot occupy the same space at the same time (collision). Wang et al. examined children's understanding of a third property (support) by investigating whether 7.5- and 8.5-month-old infants were surprised by the stable arrangement of a wide block resting on top of a small cube. When the center of the bottom of the wide block overhung the cube edge, only the older infants were surprised that it did not fall, which may signal the start of learning about the center of mass and gravity.

    Cognition 157, 100 (2016).

  3. Neuroimmunology

    Autoimmunity in narcolepsy

    1. Lisa D. Chong

    Narcolepsy is a neurological disorder characterized by sleep that can strike at any time, lasting from seconds to minutes. Most narcoleptics experience loss of muscle tone (cataplexy) and have low levels of orexin (hypocretin), a neurotransmitter that promotes wakefulness. Destruction of orexin-producing neurons in the brain is thought to cause narcolepsy. Bernard-Valnet et al. report that cytotoxic T cells infiltrate the brain, interact with orexin-producing neurons, and destroy them. The authors engineered a mouse model to express a specific self-antigen in hypothalamic neurons that produce orexin. Cytotoxic T cells that recognize this antigen infiltrated the brain and destroyed these neurons. Consequently, the animals had sleep attacks and cataplectic episodes. This potential autoimmune mechanism may provide targets for narcolepsy therapies.

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1603325113 (2016).

  4. Neurodevelopment

    Modular brain construction

    1. Pamela J. Hines

    The mammalian cerebellum looks complex on the surface, with a stereotypical pattern of lobules and fissures. Although its subregions all seem to use similar types of cells, tracts coming from elsewhere in the brain target distinct portions of the cerebellum, suggesting that surface formations reflect functional zones. Legué et al., studying developing mouse brains, showed how the proliferation and differentiation of granule cells determines the size of a fully developed lobule. Each lobule gets a different proportion of granule cell progenitors; anchoring centers at the base of developing fissures prohibit sharing. The cerebellum thus develops as a modular construction, which may enable acquisition of new functions during evolution.

    Neural Dev. 10.1186/s13064-016-0072-z (2016).

    Compartmentalized granule cells feed cerebellar development.

  5. Diversity

    Instructor gender versus student ratings

    1. Melissa McCartney

    Despite evidence suggesting that student evaluations of teaching are unreliable, they are often included in promotion and tenure criteria. How unreliable are student evaluations with respect to gender bias? Wagner et al. analyzed student evaluations of mixed-gender teaching teams at a multicultural European university. Covariates such as course leadership, teacher experience, and research quality were included in the analysis. Results showed a striking disadvantage for women, with women being 11 percentage points less likely to reach a promotion-level teaching score than men teaching the same course. Several policy implications are suggested by the authors, including the call for teacher evaluations to be adjusted for gender bias.

    Econ. Edu. Rev. 10.1016/j.econedurev.2016.06.004 (2016).

  6. Ocean Climate

    Clouds and Atlantic Ocean temperatures

    1. H. Jesse Smith

    The Atlantic Multidecadal Oscillation (AMO), which is characterized by quasi-periodic variations in sea surface temperature (SST) in the North Atlantic, has important effects on the weather and climate of the surrounding continents. Attention has been focused more on the details of the AMO in high and mid-latitudes and less on its tropical branch. Bellomo et al. present an analysis of long-term observational records for most of the past 70 years, finding evidence for a positive feedback between total cloud amount, SST, and atmospheric circulation that can strengthen the persistence and amplitude of the AMO at low latitudes. They estimate that cloud feedbacks can account for as much as nearly one-third of the observed AMO-related SST anomalies over the Atlantic tropics.

    Geophys. Res. Lett. 10.1002/2016GL069961 (2016).

  7. Superconductivity

    Combining transport and photoemission

    1. Jelena Stajic

    Angle-resolved photoemission spectroscopy (ARPES) is routinely used to map the electronic structure of complex materials. Most commonly when studying a phase transition, the spectra are recorded and analyzed as a function of temperature. Kaminski et al. expanded the use of ARPES in cuprate superconductors by taking measurements in a sample that was experiencing current flow. After taking into account the potentially confounding effects of Joule heating, the researchers found that the current destroyed single-particle coherence in an underdoped sample of Bi2Sr2CaCu2O8+δ before the normal state was reached. The technique may be useful in the study of other materials with complex phase diagrams.

    Phys. Rev. X 6, 031040 (2016).

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