London, Dec 20 : In order to overcome problems of speed and range encountered with micro air vehicles, scientists have now developed a vertical-takeoff micro aircraft.

Micro air vehicles (MAVs) are uncrewed aircraft with a wingspan of 15 centimetres (5.9 inches) or less and are commonly used by the military or police forces for surveillance.

Most of the MAVs, just like a full-sized airplane, are controlled by conventional moving aerodynamic surfaces such as flaps.

London, Dec 20 : Engineers at the University of Nevada in the US have tested a new design for a flexible bridge that can bounce back after an earthquake.

According to a report in New Scientist, the engineers used three large shake tables to test a 33.5-metre-long, 181-tonne (200-ton) bridge sporting an exotic new design.

The bridge, a quarter-scale replica of its projected real-life size, was subjected to 10 seconds of shaking like that created by an earthquake of magnitude 8.0.

The concrete used in the bridge was reinforced with "smart" nickel titanium - Nitinol - a "shape-memory" alloy commonly used in bendable spectacle frames.

Washington, Dec 20 : A computer model has successfully reproduced the birth of two real tropical cyclones that formed in the Indian Ocean in December 2006 and January 2007.

The model, called the Nonhydrostatic ICosahedral Atmospheric Model (NICAM), was developed for the supercomputer Earth Simulator at JAMSTEC (Japan Agency for Marine-Earth Science and Technology).

Washington, Dec 19 : A new research, from the Niels Bohr Institute at the University of Copenhagen in Denmark, has indicated that the orientation of Stone Age graves at the Danish passage could have an astronomical explanation.

According to the research, the Danish passage graves are most likely oriented according to the path of the full moon, perhaps even according to the full moon immediately before a lunar eclipse.

There are many Stone Age graves in Denmark, where archaeologists estimate that around 40.000 large stone graves were built from around 3500 to 3000 BC.

Only about 500 of the large passage graves, called `giant tombs' are preserved today, but one of the great mysteries is their orientation in the landscape.

Washington, Dec 18 : Embryonic stem cells could be a viable and effective alternative for testing drugs for dangerous side effects, according to a leading British researcher.

Christine Mummery, Professor of Developmental Biology at Leiden University Medical Centre in The Netherlands, has predicted that what is currently a small and sparsely funded research area will boom in coming years under US President-elect Barack Obama, who is an ardent supporter of stem cell research.

Washington, Dec 18 : Scientists at the University of California, Berkeley, US, have described a method for using sugar-producing microalgae for making biofuel.

The researchers have explained a way to genetically modify the tiny organisms, so as to minimize the number of chlorophyll molecules needed to harvest light without compromising the photosynthesis process in the cells.

With this modification, instead of making more sugar molecules, the microalgae could be producing hydrogen or hydrocarbons.