Random Samples

Science  09 May 2008:
Vol. 320, Issue 5877, pp. 725

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    Bats can help reforest the tropics, researchers in Germany say. Artificial bat roosts attract fruit-eating bats, whose droppings help spread seeds beyond the forest edge.

    Detlev Kelm of the Leibniz Institute for Zoo and Wildlife Research in Berlin and his colleagues installed simple towers made of sawdust and concrete near a Costa Rica nature reserve ravaged by agriculture and logging. The researchers wanted to lure bats out of their normal forest habitat and into the disturbed regions, which no longer had large, hollow tree trunks in which bats like to hang out during the day.

    Bats of 10 different species readily flocked to the roosts, the scientists reported online 25 April in Conservation Biology, significantly increasing the number and types of seeds in the neighborhood. “We kick-start the forest succession,” says Kelm, who adds that most of the seeds are of “pioneer” species such as nightshade, which grows well in open areas. Although artificial roosts are used for bat conservation, says Thomas Kunz, director of Boston University's Center for Ecology and Conservation Biology, the Costa Rican project is “a very novel idea” that should spur others to harness bats' ability to help restore lost habitat.


    Even field crops have caught the text-message craze. A new wireless monitoring system sends leaf temperature data to a computer, which posts the numbers to the Internet and can even text a farmer's cell phone to say it's time to water the crops.

    Growers currently under- or overwater many crops, according to plant physiologist James Mahan of the U.S. Department of Agriculture Agricultural Research Service in Lubbock, Texas. Based on 20 years of studying plant temperature stress, Mahan says he's come up with a simple and accurate way to ask a crop whether it's thirsty. Mahan found that, like animals, different plants have different ideal temperatures, around 25°C, depending on the species. In drought, cells warm up and go into heat stress. His new SmartCrop, developed with AccentEngineering company in Lubbock, uses infrared sensors staked among the plants to measure leaf temperature and records other data such as humidity.

    Northern Texas farmer Glenn Schur has used a pilot version of SmartCrop in cotton fields for 6 years and says it's saved him about 500 cubic meters of water per hectare, or more than 10% of his annual usage. The basic system was put on the market this spring for $1200; for $500 more, a modem will send the data to a computer that will crunch the numbers and send phone messages.


    Last week, the Indian space agency shot a record 10 satellites into orbit with one rocket from its space port at Sriharikota, Andhra Pradesh.

    Hoisted into orbit by India's Polar Satellite Launch Vehicle were two Indian satellites: the 700-kilogram Cartosat 2A Earth-mapping satellite and a 76-kg remote-sensing satellite that will share images with universities in poor countries. The payload also included eight “nanosatellites” from other countries, weighing between 3 and 16 kilograms each and designed to test money-saving off-the-shelf components.

    The feat is a tricky one, says G. Madhavan Nair, chair of the Indian Space Research Organisation in Bangalore. The satellites were released at 20-second intervals by small explosive devices as the rocket coasted at 7.5 kilometers per second 636 kilometers above Earth. If the timing is off the satellites can collide, and if an explosion is too strong it can damage the electronics.


    The previous record for a multiple-satellite launch was set by the Russians, who sent up eight in April 2007, 9 months after losing a cargo of 15 satellites when the rocket engine shut down prematurely.


    Linguists on a half-dozen anthropology and linguistic Web sites are singing the praises of the new World Atlas of Language Structures (WALS) online. WALS, an “awesome resource” as one fan calls it, was launched in April by the Max Planck Digital Library and the Max Planck Institute for Evolutionary Anthropology to give both scientists and nonlinguists free access to the data, maps, and analytical texts from the 2005 book and CD-ROM, The World Atlas of Language Structures. The book broke new ground by showing scientists the geographical distribution of important patterns of sounds, word structure, and sentence structure in 400 languages. The database expands the number to 2500 and makes the atlas interactive, including 141 maps linked to 6500 references.


    A tour of WALS shows the geographic origin of each language as well as the distribution of a vast range of structural properties, including phonological, grammatical, and lexical features. See, for example, the map (above) showing the distribution of “para-linguistic uses of clicks.” Or look under “English” and learn that it has a complex syllable structure but no politeness distribution in pronouns.