Dal hybrid beneficial but costly

THE HUMBLE tur or arhar dal, a traditional food crop in arid areas, is now being grown as a cash crop by farmers attracted by its high market value. Seed companies are thus showing a keen interest in a new hybrid of the dal, also known as pigeon pea (Cajanus cajan). But some scientists fear because of its high cost, the hybrid will more likely be picked up by rich farmers than subsistence farmers in the arid regions when it becomes available next year.

Insistence on dollar payments delays ocean power project

A SQUABBLE over foreign exchange is holding up India's first bid to commercially harness energy from the ocean. The government has agreed, in principle, to allow Sea Solar Power Corp -- a private US firm -- to set up a 100 mw plant off the Tamil Nadu coast using ocean thermal energy conversion (OTEC) technology. Sea Solar will put up $ 250 million for the project, but insists on being paid in dollars for the power generated. The Tamil Nadu Electricity Board, which will buy the power and supply it, is negotiating for payment in Indian rupees.

Greedy wasps damage flowers to steal nectar

CERTAIN wasps are inveterate nectar thieves. The wily insects sneak through the back door and loot nectar, damaging the flower and reducing chances of pollination and fruit formation (Current Science, Vol 26 No 10).

Car manufacturers spurring battery research

ELECTRIC cars run on batteries but work best without them. Batteries halve electric cars' speed and range and increase their cost because it is more difficult to get electricity into and out of a battery than it is to pump and burn petrol. With stricter emission controls slated for later this decade in the US, automobile manufacturers are looking for cheaper and better batteries that will run electric cars.

A close encounter with Jupiter's secrets

EN ROUTE to the sun, the spacecraft Ulysses dropped in on planet Jupiter in February this year. Launched on October 6, 1990, by the space shuttle Discovery, Ulysses -- a joint venture of the National Aeronautics and Space Administration and the European Space Agency -- has sent home valuable information on the largest planet in the solar system (Science, Vol 257 No 5076).

Quandary over eradicating useful lantana weed

SHOULD a weed that provides income to villagers be eradicated? This is the dilemma forest officials in Jhansi district of Uttar Pradesh face. The lantana bush spreads like a weed and threatens the growth of trees by competing for soil nutrients. But a poor villager can earn up to Rs 1,500 a month by weaving baskets out of lantana stems.

The smallest battery

Scientists at the University of California, Irvine, have made the world's smallest battery -- about the size of the common-cold virus (Science, Vol 257 No 5074). Chemist Reginald Penner and his co-workers stumbled on to it while trying to prove that silver and copper could be deposited as closely-spaced nanodots on a graphite surface to cause certain chemical reactions. They found the potential energy difference between electrons of the two metals behaved like a small battery.

Friendly parasites

Ever since the use of insecticides was reduced in favour of biological control, British gardeners are discovering that some pests are on the increase (Financial Times, Oct 31/Nov 1, 1992). Now, there are friendly insects to control white flies, greenhouse red spider mites and vine weevils.

Cleaner chimneys

A clean and green way to reduce acid rain has been developed by Chang Yul Cha of the University of Wyoming in Laramie. The process cuts sulphur dioxide and nitrogen oxides from coal-fired smokestacks using char and microwaves (Science, Vol 257 No 5076). The gases are absorbed as they pass through a bed of porous char. The char is microwaved to stimulate a reaction between the gases and carbon atoms in the char that results in the release of nitrogen and carbon dioxide.

Fibrous substitute

Plastics are a major environmental problem because they are not biodegradable. One exception is polyhydroxybutyrate-hydroxyvalerate (PHB-V), but manufacturing it is expensive and its use is restricted. A Swedish researcher has combined PHB-V with wood fibres to come up with an inexpensive alternative he calls "fibrewood," (Science, Vol 257 No 5076).