Science

The best in science news, commentary, and research
  • [This Week in Science] Where will H5 flu viruses travel to next?
    [Feb 2015]

    Author: Julia Fahrenkamp-Uppenbrink
    Categories: Journal Articles
  • [Editors' Choice] California drought worst in the past millennium
    [Feb 2015]

    Author: Julia Fahrenkamp-Uppenbrink
    Categories: Journal Articles
  • [Editors' Choice] Wound healing requires senescence
    [Feb 2015]

    Author: Beverly A. Purnell
    Categories: Journal Articles
  • [Editors' Choice] African origin for New World monkeys
    [Feb 2015]

    Author: Carolyn Gramling
    Categories: Journal Articles
  • [Editors' Choice] Gauging gatekeeper performance
    [Feb 2015]

    Author: Barbara R. Jasny
    Categories: Journal Articles
  • [Editors' Choice] Pathogens promote forest diversity
    [Feb 2015]

    Author: Andrew M. Sugden
    Categories: Journal Articles
  • [Review] Undergraduate research experiences: Impacts and opportunities
    [Feb 2015]

    Most undergraduates give high ratings to research experiences. Studies report that these experiences improve participation and persistence, often by strengthening students’ views of themselves as scientists. Yet, the evidence for these claims is weak. More than half the 60 studies reviewed rely on self-report surveys or interviews. Rather than introducing new images of science, research experiences may reinforce flawed images especially of research practices and conceptual understanding. The most convincing studies show benefits for mentoring and for communicating the nature of science, but the ideas that students learn are often isolated or fragmented rather than integrated and coherent. Rigorous research is needed to identify ways to design research experiences so that they promote integrated understanding. These studies need powerful and generalizable assessments that can document student progress, help distinguish effective and ineffective aspects of the experiences, and illustrate how students interpret the research experiences they encounter. To create research experiences that meet the needs of interested students and make effective use of scarce resources, we encourage systematic, iterative studies with multiple indicators of success. Authors: Marcia C. Linn, Erin Palmer, Anne Baranger, Elizabeth Gerard, Elisa Stone
    Categories: Journal Articles
  • [Research Article] Combinatorial labeling of single cells for gene expression cytometry
    [Feb 2015]

    We present a technically simple approach for gene expression cytometry combining next-generation sequencing with stochastic barcoding of single cells. A combinatorial library of beads bearing cell- and molecular-barcoding capture probes is used to uniquely label transcripts and reconstruct the digital gene expression profile of thousands of individual cells in a single experiment without the need for robotics or automation. We applied the technology to dissect the human hematopoietic system and to characterize heterogeneous response to in vitro stimulation. High sensitivity is demonstrated by detection of low-abundance transcripts and rare cells. Under current implementation, the technique can analyze a few thousand cells simultaneously and can readily scale to 10,000s or 100,000s of cells. Authors: H. Christina Fan, Glenn K. Fu, Stephen P. A. Fodor
    Categories: Journal Articles
  • [Report] Nanoscale temperature mapping in operating microelectronic devices
    [Feb 2015]

    Modern microelectronic devices have nanoscale features that dissipate power nonuniformly, but fundamental physical limits frustrate efforts to detect the resulting temperature gradients. Contact thermometers disturb the temperature of a small system, while radiation thermometers struggle to beat the diffraction limit. Exploiting the same physics as Fahrenheit’s glass-bulb thermometer, we mapped the thermal expansion of Joule-heated, 80-nanometer-thick aluminum wires by precisely measuring changes in density. With a scanning transmission electron microscope and electron energy loss spectroscopy, we quantified the local density via the energy of aluminum’s bulk plasmon. Rescaling density to temperature yields maps with a statistical precision of 3 kelvin/hertz−1/2, an accuracy of 10%, and nanometer-scale resolution. Many common metals and semiconductors have sufficiently sharp plasmon resonances to serve as their own thermometers. Authors: Matthew Mecklenburg, William A. Hubbard, E. R. White, Rohan Dhall, Stephen B. Cronin, Shaul Aloni, B. C. Regan
    Categories: Journal Articles
  • [Report] Asynchronous rotation of Earth-mass planets in the habitable zone of lower-mass stars
    [Feb 2015]

    Planets in the habitable zone of lower-mass stars are often assumed to be in a state of tidally synchronized rotation, which would considerably affect their putative habitability. Although thermal tides cause Venus to rotate retrogradely, simple scaling arguments tend to attribute this peculiarity to the massive Venusian atmosphere. Using a global climate model, we show that even a relatively thin atmosphere can drive terrestrial planets’ rotation away from synchronicity. We derive a more realistic atmospheric tide model that predicts four asynchronous equilibrium spin states, two being stable, when the amplitude of the thermal tide exceeds a threshold that is met for habitable Earth-like planets with a 1-bar atmosphere around stars more massive than ~0.5 to 0.7 solar mass. Thus, many recently discovered terrestrial planets could exhibit asynchronous spin-orbit rotation, even with a thin atmosphere. Authors: Jérémy Leconte, Hanbo Wu, Kristen Menou, Norman Murray
    Categories: Journal Articles