Editors' Choice

Science  10 Oct 2014:
Vol. 346, Issue 6206, pp. 205
  1. Astronomy

    Do young star clusters follow the law?

    1. Margaret M. Moerchen
    PHOTO: NASA/JPL-CALTECH/STSCI

    One of the enduring puzzles of astrophysics is how mass is distributed among a population of stars at their birth. Astronomers currently use modified power-law functions in an attempt to describe the initial mass function (IMF), effectively a histogram of stellar masses. Sami Dib employed Bayesian statistics to find the probability distributions of IMF parameters for eight young star clusters with similar environments and ages, in order to discover if a universally descriptive IMF exists. Surprisingly, the resulting parameters did not overlap (within 1 sigma), suggesting that there is no universal description for young clusters. These findings demonstrate the power and necessity of Bayesian statistics in IMF studies as next-generation telescopes that can resolve stellar populations in many more clusters come online.

    Mon. Not. R. Astron. Soc. 10.1093/mnras/stu1521 (2014).

  2. Tropical Forests

    Tree diversity benefits light capture

    1. Andrew M. Sugden

    Higher plant diversity in ecosystems often benefits ecological processes such as nutrient cycling and rates of growth. To better understand how such improvements might work in tropical forests, Sapijajankas et al. set up experimental plantations in Panama using seedlings of native tree species and varied the number of species in the plots. Eight years later, they measured light penetrating through the tree canopy and found that plots with six species captured more light and grew taller than those with three species or only one. The researchers linked these effects to changes in tree structure at the different levels of diversity and to differences in seasonal growth patterns of the trees.

    Ecology 95, 2479 (2014).

  3. Education

    Mind the (gender) gap...it's still here

    1. Melissa McCartney

    Unlike in mathematics, engineering, and other areas of science, the number of undergraduate female biology majors exceeds that of male biology majors. To determine whether gender disparities still exist, however, Eddy et al. looked at whole-class discussion participation and academic achievement in 23 introductory undergraduate biology classes at a large university. Despite being the numerical majority at 60%, females responded to instructorposed questions less than 40% of the time. Moreover, females scored lower on exams than their male counterparts with a similar grade point average. These results show that closing the gender gap in science education may require more than just recruitment alone.

    CBE Life Sci. Educ. 13, 478 (2014).

  4. Metabolic Control

    Membrane protein signals to mitochondria

    1. L. Bryan Ray

    Cell adhesion proteins called Fat cadherins control cell growth and tissue organization. Sing et al. now report a new function for Fat cadherins: They launch a signal that helps cells generate energy in the mitochondria. During fly development, an enzyme cuts off the cytoplasmic portion of the large Fat cadherin that spans the cell membrane. Freed from the membrane, this peptide then moves to the mitochondria, where it drives oxidative phosphorylation. These results may provide insight into the role of Fat cadherins in tumors (Fat cadherin 4 is mutated in several human cancers), which require careful metabolic regulation in order to grow.

    Cell 10.1016/j.cell.2014.07.036 (2014).

  5. Low-Cost Diagnostics

    A blood test for those who need it most

    1. Paula A. Kiberstis

    People with sickle cell disease have abnormally shaped red blood cells, which can cause anemia and disrupt blood flow, leading to organ damage. Sickle cell disease can be managed effectively when diagnosed early. But in places such as sub-Saharan Africa, which lacks the infrastructure needed for advanced diagnostic procedures, many children die of the disease. To overcome this, Kumar et al. developed a diagnostic test that is rapid, inexpensive, and could be implemented in low-resource areas. Starting with blood from a fingerstick, they used aqueous solutions of polymers to separate cells by their density. Because sickle cells have a higher density than normal cells, the scientists could easily detect them by visually inspecting the samples.

    CREDIT: DAVID MACK/SCIENCE SOURCE

    Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1414739111 (2014).

  6. Fluorocarbons

    An elusive ion caught sticking around

    1. Jake Yeston

    Trifluoromethyl groups are found in a wide variety of compounds, including such well-known drugs as Prozac and Celebrex. Chemists often incorporate them into molecules through methods that might seem to involve the intermediacy of the negatively charged CF3 anion. However, this intermediate has stayed out of sight in solution, leaving its stability in doubt. Prakash et al. now have succeeded in catching it on camera, so to speak (actually in nuclear magnetic resonance spectra). To make it, they treated CF3H and several silyl-substituted analogs with potassium t-butoxide base, and then bound the potassium counterion in a crown ether. The anion persisted for days in tetrahydrofuran solvent at minus 78°C.

    Angew. Chem. Int. Ed. 53, 10.1002/anie.201406505 (2014).

  7. Planetary Science

    Moon's ancient magma plumbing system

    1. Eric Hand

    Several kilometers below a lunar dark spot called Oceanus Procellarum lies a giant rectangle: the remnants of a geological plumbing system that spilled lava across the Moon 3.5 billion years ago, scientists say. Andrews-Hanna et al. studied density variations on the Moon's surface, mapped by NASA's GRAIL (Gravity Recovery and Interior Laboratory) spacecraft, which spotted the mysterious rectangle. Procellarum is rich in radioactive elements that produce heat; as the rock cooled, the team theorized, it would have cracked, forming rift valleys that later became channels for upwelling magma. Spilled lava created the dark spot, and the weight of that dense material formed a topographic low. The rectangular shape also casts doubt on the decades-old theory that the circular Procellarum region is a crater created by the impact of a large asteroid.

    Nature 10.1038/nature13697 (2014).

  8. Evolutionary Biology

    Whales put their pelvic bones to good use

    1. Sacha Vignieri
    CREDIT: © STEPHEN FRINK COLLECTION/ALAMY

    As organisms adapt to their environment, they lose traits that are no longer beneficial or keep them in much reduced form. Such “vestigial” traits may be on their way out, but sometimes they can also acquire new functions. Dines et al. show that the reduced pelvic bones of cetaceans (marine mammals such as whales, porpoises and dolphins) may fall into the latter category. They found that these bones anchor the muscles that control the highly dextrous penis found in many cetacean species. Moreover, species in which male competition for females is high have both large pelvic bones and penises relative to their body size.

    Evolution 10.1111/evo.12516 (2014).

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