Top science, nature & history research from around the world
Dust particles and birth of new stars
A dying star produces a stream of gas and dust, which removes as much as half of its mass. It was thought this 'superwind' included minute dust particles, but models show these would have evaporated. Now, using the Very Large Telescope in Chile, astronomers have spotted that the dust grains grow larger than what had previously been thought and act like mirrors rather than absorb the heat. This means the dust grains can be pushed out by the starlight, eventually forming new stars.
A carnivorous dinosaur that was 9-m (30-ft) long would have sported a fuzzy down of feathers, palaeontologists have discovered. Weighing 1.5 tonnes, Yutyrannus huali, which means 'beautiful feathered tyrant', was 40 times larger than any previously known feathered dinosaur. The feathers were spotted in fossils found in northeastern China and were probably an adaptation to the cool climate at the time when Yutyrannus, an ancient relative of Tyrannosaurus rex, was alive in the early Cretaceous period.
A food scarcity causes a rise in the proportion of newborn babies being girls rather than boys or at least that's what happened during the Great Leap Forward famine in China in the 1950s and 1960s, a tragedy prompted by a Communist Party policy of shifting workers from the land into industry. The recent discovery supports the sex ratio adjustment hypothesis that suggests mothers in good condition are more likely to give birth to sons, whereas mothers in poorer health are more likely to give birth to daughters.
The gene responsible for the distinctive sunflowers immortalised in Vincent van Gogh's paintings — the flowers lack a large dark centre and feature a mass of golden petals — has been discovered. Sunflower heads are actually made up of many tiny flowers, or florets. Typically, there are golden ray florets at the rim, which resemble long petals, and disc florets at the centre. In Van Gogh's sunflowers a chunk of DNA would have been added to one gene so the central florets took on the appearance of golden rays.
A chemical analysis of the bones of 19th century British sailors who served under Admiral Nelson has shone fresh light on their diets. Archaeologists analysed the isotopes discovered in the remains of 80 sailors buried in southern England and found that sailors ate more heartily than many of their contemporaries did. But a comparison with a previous analysis of the bones of sailors aboard the 16th century ship the Mary Rose show the naval diet had changed little in the subsequent 200 years.
A modified version of an enzyme produced in our bodies could provide a new form of defence against chemical weapons such as sarin, used in Tokyo subway attack in 1995. Paraoxonase 1 was known to break down 'G-type' nerve agents like sarin, although it doesn't do so particularly effectively. Now, scientists in Israel have modified Paraoxonase 1 genes to produce new forms of the enzyme that are up to 3,400 times more efficient at breaking down the three most toxic G-type nerve agents.
Exactly how the humble pigeon can navigate hundreds of miles is a question that remains up in the air. Pigeons are able to detect the Earth's magnetic field — useful for navigation — and it had been thought that this ability was due to nerve cells in the bird's beak containing the iron-rich mineral magnetite. But advanced imaging techniques show that this iron is actually contained inside white blood cells called macrophages, which are involved in defending against infection rather than relaying information to the brain.
Content courtesy BBC Knowledge Magazine October Issue On Stands