- Behavior
Biting into Big Data in the Big Apple
- Gilbert Chin
Default choices drive taxi tipping
PHOTO: © AGF SRL/ALAMY
Default options are an effective means of influencing consumer choices: With opt-out choices as defaults, people donate more organs and set aside more money for retirement. But how do people respond when faced with short-term choices in everyday life? Haggag and Paci analyzed 13 million taxi rides taken in New York City in 2009. They find that most customers press one of the default option buttons (for example, a $3 tip for a ride under $15) that specify the amount to tip the driver—enough to raise the average amount tipped across the full sample. Alternatively, some riders opt instead to leave no tip at all.
Am. Econ. J. Appl. Econ. 10.1257/app.6.3.1 (2014).
- Catalysis
Simpler coating of silica surfaces
- Phil Szuromi
Organic coatings often are applied to silica surfaces found in optics, catalysts, and drug delivery systems in order to improve their functional properties. These coatings typically are formed by reacting surficial hydroxyl groups with organosilicon compounds. However, that approach requires either stringent reaction conditions or long reaction times. Moitra et al. show that silica can be coated in a few minutes with hydrosilanes, using a fluoro-organoborane catalyst. Hydrosilanes can bear a wide variety of functional groups, making this a versatile method.
J. Am. Chem. Soc. 136, 11570 (2014).
- Antibiotic Resistance
Clone wars: Let's pick out the superbugs
- Caroline Ash
Since the 1960s, group B streptococci (GBS) have lost genetic diversity, yet they cause more virulent neonatal infections and show high rates of tetracycline resistance. The puzzle is that tetracycline is not used to treat GBS. Nevertheless, since the 1950s, most GBS clones were wiped out by the collateral effects of the widespread use of tetracycline and other antibiotics, even though they were not the treatment target. Da Cunha et al. show that a few GBS clones survived by virtue of their persistence or virulence, and these clones also acquired mobile genetic elements carrying a mixture of antibiotic resistance genes, including those for tetracycline resistance.
Nat. Comm. 10.1038/ncomms5544 (2014).
- Signaling Bone
Signaling back and forth for cartilage
- Beverly A. Purnell
Skeletal bones provide body structure and protect inner tissues, but if they form in the wrong place, major problems result. Bone development begins with the aggregation of mesenchymal cells and their association with cartilage cells, which are then replaced by bone. Signaling molecules called Wnts limit expression of the SOX9 gene, which is needed for cartilage development. Too much SOX9 makes inappropriate cartilage. Kumar et al. show that Wnts limit cartilage development in the limb by chemically modifying the Sox9 gene and the histone protein that surrounds part of the gene. Another cell signal, called FGF, promotes cartilage development by blocking chemical modification.
Cell Rep. 10.1016/j.celrep.2014.07.038 (2014).
- Immunology
Gut bugs may boost flu shots' effects
- Kelly Servick
Why do some people get the flu after the flu shot? The answer may be in the gut. While studying gene expression and the strength of the immune response in people infected with influenza vaccine, Oh et al. found a surprise: The gene that codes for the protein toll-like receptor 5 (TLR5) which is linked to gut bacteria, was also linked to strong immune response. The team gave flu vaccine to mice, some engineered to lack gut microbes and some to lack the gene for TLR5. Seven days later, the mice had significantly reduced levels of vaccine-specific antibodies in their blood as compared with control mice, suggesting that bacterial signaling boosts the vaccine's effect.
Immunity 10.1016/j.immuni.2014.08.009 (2014).
- Animal Cognition
Getting by with a little help from eel friends
- Sacha Vignieri
Collaboration is an essential component of human behavior. Many other species are known to collaborate as well. For example, coral trout collaborate with moray eels, recruiting the eels to flush out prey hidden in crevices. Vail et al. show that the trout chose to recruit eels under the appropriate conditions (i.e., when prey were hidden). Further, after their first experience with particular eel collaborators, the trout more often chose those eels that were more willing to join in. These results suggest that the cognitive ability to assess appropriate collaborators and conditions is more widespread than previously believed, and likely due more to ecological need than shared ancestry.
Curr. Biol. 10.1016/j.cub.2014.07.033 (2014).
- Physics
Magnetism leads to superconductivity
- Jelena Stajic
Some materials become perfect conductors of electricity—superconductors—when they are cooled to low enough temperatures. In a superconducting material, electrons pair up with each other to form Cooper pairs, a counterintuitive phenomenon because we usually think of electrons as mutually repulsive. The electrons in these pairs must be “glued” together with a mediating interaction, but the nature of the glue is known reliably only for the simplest, conventional kind of superconductors. Van Dyke et al. provide strong evidence that magnetic interactions mediate the pairing in the unconventional superconductor CeCoIn5. They used a scanning tunneling microscope to measure the electronic structure of the material, and then used those measurements to extract the material's magnetic interactions and calculate its superconducting properties. The results agreed well with independent experiments.
Proc. Natl. Acad. Sci. USA 111, 11663 (2014).
- Volcanology
Reservoir assembly drives super-eruptions
- Brent Grocholski
Geyser remnant of the Heise volcanic super-eruption
PHOTO: © JEFF VANUGA/CORBIS
Volcanic super-eruptions are hundreds to thousands of times larger than nearly any volcanic eruption that has occurred in recorded human history. Woltzlaw et al. looked for clues about what triggers these unimaginable events in minerals that formed in volcanic rocks. They analyzed zircons from the last super-eruption of the now-extinct Heise volcanic field and found that erupted magma was stored underground for a surprisingly short time, only about 5000 years. Furthermore, magma production occurred in distinct batches, forming thin sheetlike structures called sills. When many sills located at different depths connect with each other, the magma quickly becomes more buoyant, which may trigger these massive eruptions.
Geology 10.1130/G35979.1 (2014).
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