Science at Atheist Universe
VIDEO THE WEEK: Zooming in from the constellation Aquarius, the Helix Nebula -- NGC 7293 -- comes into view. The final image (lacking the blue cloudiness of dust and gas) shows Helix in infrared light, as seen by the VISTA telescope at the Paranal Observatory in Chile.
See more great astronomy videos and photos in our group The Daily Cosmos
And more beautiful ASTRONOMY: Amazing new photos of the Milky Way, taken by NASA. This composite image of the Milky Way galaxy is a mosaic of infrared images from NASA's Wide-field Infrared Survey Explorer. The constellations Cassiopeia and Cepheus are both visible in this 1,000-square degree image, as are dozens of dense clouds, called nebulae, where new stars are forming.
EVOLUTION: Yeast provides a hint for the evolution toward multicellular life. All of us have evolved from single cell organisms. The first step to multicellularity is a mystery, but now the lowly brewer's yeast is giving us a hint of how it could have happened, by "evolving" into a "primitive body" in just two weeks. University of Minnesota microbiologists have designed one of the cleverest experiments ever: they let yeast grow in agitated tissue culture flasks and then stop the agitation and let the yeast cells settle; then they took settled from the bottom of the flask, re-seeded them in another flask, and repeated the experiment. Very quickly, cells evolved to settle quickly (the ones that did not settle quickly were never passed on to the new flask). But the fast-sinking cells were not single cells anymore: they held on together and formed a snowflake-like structure. The structure was formed by daughter cells not fully separating after cell division. What was even more amazing, is that after the clumps reached a certain size, some cells "committed suicide" (named apoptosis, or programmed cell death) so some daughter cell clumps could separate into their own clumps. This suggests that the cells are no longer acting as individuals since some of them "sacrificed" for the good of the new "organism". Given these lab results, it is no surprise that multicellularity has arisen more than once in the history of life on Earth. At some points, conditions must have favored multicellularity over single cells. The closest living unicellular relatives of multicellular organisms, the choanoflagelates, are known to ssometimes form clumps of cells that stay together, like this Sphaeroeca colony in the photo below.
ANIMAL BEHAVIOR: Impulse control and dog genetics. Is your dog a calm fellow or do you have a more challenging friend who has trouble with impulse control and is hard to calm down once aroused? I don't think I ever had a very calm dog in my life, although some were easier to train that others. My two dogs have impulse control issues, although the male, Nero, can be coaxed into calming down more easily that my female, Lola. Lola is like a tightly wound rope, once unwound, it's hard to get back to its original shape. If there is food around, she can't control herself, she will beg, whine, perform tricks all by herself, until she gets a piece of the treat. If there is a dig that barks at her, or a dog she dislikes, she will get all up in arms and it is very hard to get her to calm down. Dogs, like people, have their quirks and their personalities. And now science has brought us closer to understanding the basis for impulse control levels in doggies: there is a gene, called tyrosine hydroxylase (TH for short), involved in the production of neurotransmitters, which is associated with activity-impulsivity in German Shepherd dogs. The gene has two varieties, a short allele and a long allele. Dogs with at least one copy of the shorter version of the gene had more trouble controlling their impulses and were more hyperactive than dogs with two long alleles. My sister's German Shepherd, Vasco, must have had two long alleles, because he was a really calm dog, highly trainable, like the pup in the photo. The researchers will now confirm their finding in other breeds. The findings could also extrapolate to humans.
ANIMAL PHYSIOLOGY/PHYSICS: How do small animals manage to fly in the rain? A fascinating post by Doone, on research done by someone dear to his heart. Have you ever wonder how animals such as mosquitos can fly in the rain, when a raindrop is bigger than the mosquito? When hit by a drop, mosquitos manage to quickly recover their flight position, despite accelerations of 30-300 gravities over durations of 1 ms (milliseconds). To learn about the physics behind this remarkable phenomenon, read the discussion. It also includes other small flyers such as hummingbirds and how they shake off the rain.
NANOTECHNOLOGY: Scientists Create World's Tiniest Ear. Scientist have created the smallest ever artificial "ear", gold nanoparticles trapped in a laser beam, that can pick up sounds 1,000,000 times fainter than our human ear threshold. The invention relies on so-called "optical tweezers", laser beams that can grab tiny particles and move them around. Gold nanoparticles held by the laser beam vibrate in response to sound waves and the vibration can be recorded as a movement. The applications are still not clear, but they could include "listening" to cells or viruses and bacteria move.
SPECIAL FEATURE: Ten Historic Female Scientists You Should Know. None of this pioneer scientist is alive today, but their legacy is still very much alive. I salute all these women scientists, and I’m ashamed to say I knew only two of them really well, Barbara McClintock and Rosalind Franklin (in the photo).
Rosalind Franklin (1920 – 1958)
James Watson and Francis Crick get credit for determining the structure of DNA, but their discovery relied on the work of Rosalind Franklin. As a teenager in the 1930s, Franklin attended one of the few girls’ schools in London that taught physics and chemistry, but when she told her father that she wanted to be a scientist, he rejected the idea. He eventually relented and she enrolled at Cambridge University, receiving a doctorate in physical chemistry. She learned techniques for X-ray crystallography while in Paris, returning to England in 1951 to work in the laboratory of John Randall at King’s College, London. There she made X-ray images of DNA. She had nearly figured out the molecule’s structure when Maurice Wilkins, another researcher in Randall’s lab who was also studying DNA, showed one of Franklin’s X-ray images to James Watson. Watson quickly figured out the structure was a double helix and, with Francis Crick, published the finding in the journal Nature. Watson, Crick and Wilkins won a Nobel Prize in 1962 for their discovery. Franklin, however, had died of ovarian cancer in 1958.
Science bits and news from other sites:
Astounding Photographs of Jellyfish by Alexander Semenov. Russian biologist Alexander Semenov graduated in 2007 from Moscow State University’s zoology department where he studied invertebrate animals. He is now chief of a diving team at the White Sea Biological Station, camera always in-hand, where he’s captured some of these extraordinary photographs of jellyfish and other wildlife. They are astonishingly beautiful. Go to the link to see them all.
The normally vegetarian orangutans have been seen hunting and eating other primates, specifically the slow loris (the scientific name is Nycticebus coucang, and it is a really, really cute animal, see video below). Orangutans only seem to do this when fruit is scarce, indicating that meat may represent a filler fallback food. In all occasions, the orangutans first stunned their prey, and swiftly killed it with a bite to the head, the reason being that the slow loris bite is toxic. Slow lorises are the only primates with poisonous saliva! The total number of cases observed has been only 9, so it is something that they do only extraordinarily. Orangutans eat their meat more than twice as slowly as chimpanzees, chewing it thoroughly. Using orangutan data as a model, researchers calculated that the time spent chewing per day would not have been excessive for our ancestors the australopithecines and later, hominids) as long as meat represented no more 25% of their diet.
Starfish have bilateral tendencies. As you all know, starfish have five-sided symmetry, and they can move in all directions, leading with any arms. But researchers have found that these echinoderms have hidden bilateral tendencies, which they manifest under stress. The fact that they can move in a bilateral way is not entirely surprising since starfish larvae, unlike adults, have bilateral symmetry. The scientists studied starfish in the lab, exposing them to various environmental challenges to see how they would react and to see which arm would lead, for example, when they were crawling away to hide after being dropped in an unfamiliar tank. They also flipped the over and recorded how they righted themselves. They also put drops of an irritating substance on their back to see how they moved away. In all these stressful situations, the starfish moved according to a bilateral symmetry pattern, leading mostly with the fifth arm. And if you’re wondering how the researchers know which arm is which, this is based on the madreporite, a hole in the central disc, which allows water to come into the animal, which is asymmetric, opposite to arm 1; from there, the convention is to count the arms clockwise. Acting as if they had bilateral symmetry allow the animal to have a preferred direction for moving, which could allow for a faster response to moving away from danger.
Sustainable biofuel from seaweed. Biofuels are currently extracted from crops, such as ethanol from corn. But now bioengineers have come up with a way to produce ethanol from seaweed, which one day could circumvent the need use food crops for biofuel, and could also be more sustainable. Seaweed is very abundant, and varieties such as the giant kelp, found off the coast of California, grow by up to 1 m (3 feet) per day. Scientists managed to extract ethanol from brown seaweed by engineering a common bacterium, E. coli, to digest the algae and produce ethanol as a result. Producing biofuels from seaweed has been tricky up to now, because most of the sugar in seaweed is alginate, a complex polysaccharide that is difficult for most bacteria to digest. The scientists first isolated the genes responsible for breaking down alginate in a marine bacterium, Vibrio splendidus, and then engineered these genes into a lab strain of E. coli. This modified E. coli can be easily grown. The biggest obstacle now remains how to cultivate and harvest the several thousand tons of seaweed a year that would be required to produce sufficient ethanol to be useful. The feasibility of this ethanol-production process will be tested at a pilot plant being built in Chile.
A piece of Mars found in Morocco. Last July, a meteorite fell on Moroccan, near the village of Tissint. About a dozen pieces of the meteorite were recovered last December. Since the pieces had been on Earth for only six months before being collected, the contamination by earthy materials is minimal. Geologists could determine that the meteorite, named Tissint, originated in Mars. The rocks, which are volcanic, were identified as Martian by their oxygen isotope ratios, which are different than those for rocks coming from our planet or from other sources in space. This is important because only a handful of meteorites have been confirmed as Martian in origin. This is first Mars meteorite in 40 years! Although the chance of finding organic matter is remote, scientists will keep looking because the meteorite is so “fresh”.