Science Links for 8/15/2014

Article: Huge asteroid that 'could end human life' defying gravity as it moves towards Earth, scientists say

It "defies gravity" by rotating on its axis so fast that its surface at its equator actually experiences "negative gravity."

Asteroids are a collection of dust and rubble. Normally, they are held together held together by gravity, but this one is rotating so fast that it is held together by van der Waal's force. [A weak force that is due to attraction between molecules. It is related to hydrogen bonding.]

Article: Who's your mummy? Egyptian mummification older than was thought

Researchers on Wednesday said a form of mummification was being carried out there more than six thousand years ago, much earlier than previously thought. They said embalming substances contained in funerary textiles from the oldest-known Egyptian cemeteries showed mummy-making from as early as about 4300 BC.

There is evidence of mummification involving remains from around 2600 BC of Queen Hetepheres, mother of Khufu, the pharaoh who commissioned the Great Pyramid at Giza outside Cairo. There also is evidence of linen that contained resin being used to wrap bodies around 2800 BC.

The researchers were amazed to find that the plant, animal and mineral components used in preparing the mummies at the cemeteries in Mostagedda in central Egypt were essentially the same embalming "recipe" used thousands of years later at the pinnacle of the ancient Egyptian civilization.

Article: Little penguins forage together: 40% of studied penguins synchronized underwater movements while foraging

Olympic synchronized swimming for penguins!

Little penguins are the smallest penguin species and they live exclusively in southern Australia, New Zealand, and the Chatham Islands, but spend most of their lives at sea in search of food. Not much is known about group foraging behavior in seabirds due to the difficulty in observing their remote feeding grounds.

The authors GPS devices to track the little penguins.

The authors found that ~ 70% of little penguins' foraging tracks were in association with other penguins, ~ 50% of individuals dove while associating with other penguins, and ~ 40% exhibited synchronous diving. These behaviors suggest little penguins forage in groups, may synchronize their underwater movements, and potentially cooperate to concentrate their small-schooling prey.

Article: Ebola outbreak: the vaccine and 'secret serum' explained

Vaccines exist, but have not been tested on humans. They seem to give protection to monkeys. Because Ebola outbreaks are usually localized and limited. Vaccination will never be wide-spread (like polio or smallpox), and mostly given to health workers and the like.

This drug [the "secret serum'"] gives you antibodies directly, rather than waiting two to three weeks after vaccination for the antibodies to work. It could be used for treatment whereas a vaccine is more likely to be used for prevention.

Article: Competition for ecological niches limits evolution of new species

The article is worth skimming just for pictures of the birds.

Most new species are thought to arise in a three step process: First, a species expands its range. Then a barrier, such as a geographic event, separates the species into distinct populations. Last, development of the inability to interbreed -- reproductive isolation -- finalizes the speciation process. As this cycle repeats, it gives rise to a vast diversity of plant and animal species. 

In this study, Professor Price, Dr Mohan and their colleagues used several approaches to examine how geographic differences affect speciation by testing the niche-filling model: first, they asked whether the geography of the eastern Himalayas provided a greater number and diversity of niches that songbirds could occupy and adapt to. Second, they examined whether the rate of oscine speciation changed over time. Third, they investigated the diversity and abundance of resources available in different ecological niches.

These findings suggest that speciation and geography are intimately connected in the evolutionary history of the Himalayan songbird assemblage: initially, numerous morphological differences in feeding method and body size appear early in their evolutionary history, whereas only later did the fledgling species invade and adapt to available ecological niches at different elevations. Since available niches were filling up as new species moved in, younger and younger songbird species were usually competing for smaller and smaller niches. These findings are all consistent with the niche-filling model.