Formation of Diverse Supercrystals from Self-Assembly of a Variety ofPolyhedral Gold Nanocrystals

Ching-Wen Liao †, Yeh-Sheng Lin †, Kaushik Chanda †, Yen-Fang Song ‡, and Michael H. Huang *†
† Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
‡ National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan

Adaptive aerial righting during the escape dropping of wingless pea aphids

• Gal Ribak^1, #, ,  , Moshe Gish^2, #, Daniel Weihs¹ and Moshe Inbar²

  http://www.cell.com/current-biology/abstract/S0960-9822(12)01450-9

  Summary

• Pea aphids (Acyrthosiphon pisum) are small sap-sucking insects that live on plants in colonies containing mostly wingless individuals. They often escape predators, parasitoids and grazing mammalian herbivores by dropping off the plant [1,2], avoiding immediate danger but exposing themselves to ground predators, starvation and desiccation [3]. We show here that dropping pea aphids land on their legs, regardless of their initial orientation on the plant (like a defenestrated cat), by rotating their body during the fall. This righting ability is intriguing, as wingless aphids have no specialized structures for maneuvering in mid-air. Instead, they assume a stereotypic posture which is aerodynamically stable only when the aphids fall right-side up. Consequently, the body passively rotates to the stable upright orientation, improving the chance of clinging to leaves encountered on the way down and lowering the danger of reaching the ground.

Jet-stream shifts linked to ozone

Detecting Ozone- and Greenhouse Gas–Driven Wind Trends with Observational Data

1. Sukyoung Lee¹,*, 
2. Steven B. Feldstein¹

ABSTRACT

Modeling studies suggest that Antarctic ozone depletion and, to a lesser degree, greenhouse gas (GHG) increase have caused the observed poleward shift in the westerly jet during the austral summer. Similar studies have not been performed previously with observational data because of difficulties in separating the two contributions. By applying a cluster analysis to daily ERA-Interim data, we found two 7- to 11-day wind clusters, one resembling the models' responses to GHG forcing and the other resembling ozone depletion. The trends in the clusters' frequency of occurrence indicate that the ozone contributed about 50% more than GHG toward the jet shift, supporting the modeling results. Moreover, tropical convection apparently plays an important role for the GHG-driven trend.

Does brain size matter?

1. L. Bryan Ray

Brain size correlates roughly with intelligence. So, assuming that more intelligence gives a selective advantage, what limits the size of our heads? To see if bigger brains are better and what the tradeoffs might be, Kotrschal et al. experimentally addressed the effects of selection for brain size in guppies (Poecilia reticulata). After only two generations of selection, the authors obtained populations of fish whose brains were larger or smaller than normal and differed from one another by about 10%. The big-brained female fish (but not the males, for some unknown reason) were better than those with smaller brains at a task where the fish associated the number of symbols (two or four) with a food reward. The cost of the increased brain power was a decrease in the size of the gut and a decrease in reproductive function. The brain is very active metabolically, and thus its growth must be balanced against the cost of maintaining other processes in the organism. The offsetting effect on reproductive function is consistent with interspecies comparisons in which more intelligent mammals, such as humans, whales, and dolphins, have decreased fertility.

Curr. Biol. 23, 168 (2013).

Superhydrophobic and olephobic coating

This material is quite amazing given that it repels almost every liquid. Future application might lead to waterproof phones.

REVEALING INVISIBLE CHANGES IN THE WORLD

MIT