In Nature this week

August 3, 2007

  1. Baboons in social situations, and what it tells about us:

    First, they lure the reader in with wonderful anecdotes, such as Ahla, the goat-herding baboon, who spontaneously recognized the relationships among her goats, and compulsively reunited any lost baby goats with their mothers. Or there’s the orphaned baboon who, when separated from his group, cleverly spent a few days under the protection of vigilant groups of impala, and later vervets, before a jubilant reunion with his fellow baboons.

    Next they provide experimental evidence to tease apart what baboons really know about social relationships and how they use this information to get ahead in the world.

  2. Controlling intrinsic magnetic properties of materials:

    The presence of non-magnetic atoms can create a random internal field in magnetic crystals. Tuning that field from outside allows the intrinsic magnetic properties of the material to be precisely controlled.

  3. Domain wall movement in magnetic nanowires:

    When two ‘bits’ of magnetic information race around a nanoscale wire, two factors determine whether or not they survive the course: the condition of the track, and how fast they respond to the starting signal.

In Nature this week

April 13, 2007

  1. Obituary to Knut Schmidt-Nielsen: McNeill Alexander recalls the man and his work; in the process he summarises the many important discoveries made by Schmidt-Nielsen:
    • Kangaroo rats minimise water loss by producing very concentrated urine, cooling the air that they exhale in the nasal cavity, which was cooled in the first place while inhaling, and living in burrows during day and venturing out only at night;
    • in contrast to kangaroo rats, dogs breathe in through the nose and breathe out through the mouth; thus, they let water vapour to evaporate helping them lose the extra heat generated by exercise;
    • camels avoid water loss by increasing their body temperature as the day progresses, and by drying the air that they exhale using the hygroscopic surfaces of their nasal cavities;
    • sea birds which drink sea water secrete droplets of concentrated salt solutions in their nostrils and shed them by the shake of their heads;
    • unlike mammalian lungs, in the lungs of birds the air-flow is one-way–it enters at one end and leaves another, and the counter current flow of blood and air helps in high rate of oxygen absorption in the blood to power their flight;
    • for a given body mass, swimming is cheaper than flight which is cheaper than running.
  2. Amazing indeed!

  3. Bending crystals by light: Michael McBride, in a news and views piece, writes about the recent experiments of Kobatake et al to use light induced chemical transformation to bend crystals–reversibly, so that they can be bent cyclically:

    The authors grew crystal needles (about 200 \mum long and 5 \mum in diameter) by sublimation so as to be attached at one end to a microscope slide. When illuminated from the side by an ultraviolet laser pulse, the needles bent within a millisecond, displacing the free end by 50 \mum. As a dramatic demonstration of this effect, the needles can launch a tiny gold sphere as if it were a tennis ball…The reversibility of this movement is particularly noteworthy — the needles can undergo 80 cycles of photochemical bending and straightening with no apparent damage to the crystal integrity, nor any diminution in displacement amplitude.

    You can see the movies of the crystal moving gold balls as well as other light induced mechanical movement at the supplementary information page. Wow! is all I can say.

  4. The quantum mechanical basis of photosynthesis: Roseanne Sension, in a News and Views piece, while commenting on the mapping of electronic states using two-dimensional Fourier transform spectroscopy in Fenna–Matthews–Olsen bacteriochlorophyll complex by Engel et al, indicates how energy transfer during photosynthesis is inherently quantum mechanical; she further feels that this discovery might be the key to designing artificial solar energy harvest systems. Considering the fact that

    In higher plants and certain bacterial systems, the initial steps of natural photosynthesis harness light energy with an efficiency of 95% or more,

    this certainly is a very important piece of information to have.

Have fun!

In Nature this week

March 16, 2007

The latest issue of Nature is a Linnaeus special issue:

Linnaeus himself sought a universal classification of all creation, animal, vegetable and mineral. His categorizations were not uniformly valuable, but his systematic spirit, his stress on the concept of species, and the formal but adaptable conventions of nomenclature he introduced have endured. Nature is glad to celebrate his legacy in this special issue.

John Whitfield writes about the need for geneticists and evolutionary biologists to work together in updating the tree of life; Emma Marris writes on the legacy of Linnaeus and conservation; Brendan Borrel asks if amateur naturalists are bad for science; Henry Nicholls writes about Linnaeus, the anatomist and pet keeper:

Not many people would respond to the death of a pet by dissecting it. But Carl Linnaeus was an exceptional man.

H C J Godfray Jr., asks about the relationship of taxonomy to the rest of biology; in the process, he has some interesting observation to make:

Linnaeus would have been a ‘techie’, exploiting the Internet and other modern means of coordinating data.

In a similar vein, Sandra Knapp et al argue for purely web based taxonomies; in a bit of interesting science history, Staffan Mueller-Wille lets us in on a secret known only to botanists:

Carl Linnaeus’s use of erotic language to describe plants ultimately helped him to recruit a global network of specimen collectors.

So, there is not much of materials science for me to write about this week; but, a biological break is nice too — Have fun!